Method for admitting new connections based on measured quantities in a multiple access system for communications networks
6 claims: 4 independent, 2 dependent
- 1【特許請求の範囲】 【請求項1】 無線通信ネットワークにおいて、測定された量に基づいて基地局に対して新しいコネクションを許可するための方法であって、前記ネットワークは基地局および複数のリモート・ホストを含み、それらの間にアップリンクおよびダウンリンクのパケットが流れ、 前記基地局において、アップリンクのフレーム・エラー・レート、アップリンクの平均ビット・レート、アップリンク・トラヒックのバースト性ファクタ、およびアップリンク・パケットの消失レートを、前記の各リモート・ホストに対して測定するステップと、 前記の各リモート・ホストにおいてダウンリンクのフレーム・エラー・レート、ダウンリンクの平均ビット・レート、前記基地局からのダウンリンク・トラヒックのバースト性ファクタ、およびダウンリンクのパケット消失レートを測定するステップと、 前記の各リモート・ホストからの前記ダウンリンクのフレーム・エラー・レートを前記基地局に対して送信するステップと、 前記リモート・ホストの平均およびピークのビット・レート、トラヒックの前記バースト性ファクタ、および各リモート・ホストの前記パケット消失レートに基づいて、各リモート・ホストに対する等価バンド幅を前記基地局において計算するステップと、 前記リモート・ホストのすべてに対する合計の等価バンド幅に基づいて、許容できるコネクションの等価な数を前記基地局において計算するステップと、 前記の新しいコネクションが許可されたとしたときに、既に許可されるすべてのコネクションのサービスの品質が維持され得るかどうかを前記基地局において判定するステップと、 前記の既に許可されているコネクションの前記サービスの品質が維持され得る場合、あるいは前記の既に許可されているコネクションのうちの少なくとも1つを切り離し、前記の新しいコネクションによって置き換えることが、前記の既に許可されているコネクションの他のすべてに対する前記のサービスの品質を損なうことなしに行われる得る場合にのみ、前記新しいコネクションを許可するステップを組み合わせて含む方法。
- 2【請求項2】 請求項1に記載の方法において、コネクションの等価な数を計算する前記ステップが、前記新しいコネクションによって要求されている平均のレートおよびパケット消失レートの効果を考慮に入れるステップを含む方法。
- 3【請求項3】 無線通信ネットワークにおいて、測定された量に基づいて基地局に対して新しいコネクションを許可するための方法であって、前記ネットワークは基地局および複数のリモート・ホストを含み、それらの間にアップリンクおよびダウンリンクのパケットが流れ、 前記基地局においてアップリンクのフレーム・エラー・レート、アップリンクの平均ビット・レートの測定値、アップリンク・トラヒックのバースト性ファクタ、およびアップリンク・パケットの消失レートを前記の各リモート・ホストに対して測定するステップと、 前記の各リモート・ホストにおいてダウンリンクのフレーム・エラー・レート、ダウンリンクの平均ビット・レートの測定値、前記基地局からのダウンリンク・トラヒックのバースト性ファクタ、およびダウンリンクのパケット消失レートを測定するステップと、 前記の各リモート・ホストから前記基地局に対して、前記ダウンリンクのフレーム・エラー・レート、前記ダウンリンクの平均ビット・レートの測定値、前記基地局からのダウンリンク・トラヒックの前記バースト性ファクタ、および前記ダウンリンクのパケット消失レートを送信するステップと、 前記基地局において、前記リモート・ホストの平均およびピークのビット・レート、前記バースト性ファクタ、および前記パケット消失レートに基づいて、各リモート・ホストに対する等価バンド幅を計算するステップと、 前記リモート・ホストのすべてに対する合計の等価バンド幅に基づいて、許容できるコネクションの等価な数を計算するステップと、 前記の新しいコネクションが許可されたとしたときでも、既に許可されるすべてのコネクションのサービスの品質が維持され得るかどうかを前記基地局において判定するステップと、 前記の既に許可されているコネクションの前記サービスの品質が維持され得る場合、あるいは前記の既に許可されているコネクションのうちの少なくとも1つを切り離し、前記の新しいコネクションによって置き換えることが、前記の既に許可されているコネクションの他のすべてに対する前記のサービスの品質を損なうことなしに行われる得る場合にのみ、前記新しいコネクションを許可するステップとを組み合わせて含む方法。
- 4【請求項4】 請求項3に記載の方法において、コネクションの等価な数を計算する前記ステップが、前記新しいコネクションによって要求される平均のレートおよびパケット消失レートの効果を考慮に入れるステップを含む方法。
- 5【請求項5】 無線通信ネットワークにおいて、測定された量に基づいて基地局への新しいコネクションを許可するための方法であって、前記ネットワークは1つの基地局および複数のリモート・ホストを含み、それらの間でアップリンクおよびダウンリンクのパケットが流れ、前記方法は、 前記基地局において、アップリンクビットレート、アップリンク・トラヒックのバースト性ファクタ、およびアップリンク・パケットの消失レートを、前記リモート・ホストの少なくとも1つに対して測定するステップと、 前記基地局において、前記リモート・ホストの平均およびピークビットレート、トラヒックの前記バースト性ファクタ、および前記リモート・ホストの前記パケットの消失レートに基づいて、前記リモート・ホストに対する等価バンド幅を計算するステップと、 すべての既に許可されたコネクションに対してすべての等価バンド幅に基づいて、許可できるコネクションの等価な数を計算するステップと、 前記新しいコネクションは許可されるときでも、前記すべての既に許可されたコネクションのサービスの品質を判定するステップと、 前記リモート・ホストの前記既に許可されたコネクションの前記サービスの品質が維持できる場合か、または前記既に許可されたコネクションの少なくとも1つが前記既に許可されたコネクションの前記サービスの品質を損なうことなく、切断でき、かつ前記既に許可されたコネクションの他のすべてへの前記新しいコネクションによって置き換えることができる場合にのみ前記新しいコネクションを許可するステップとを組み合わせて含む方法。
- 6【請求項6】 無線通信ネットワークにおいて、測定された量に基づいて基地局への新しいコネクションを許可するための方法であって、前記ネットワークは1つの基地局および複数のリモート・ホストを含み、それらの間でアップリンクおよびダウンリンクのパケットが流れ、前記方法は、 前記基地局において、アップリンクビットレート、アップリンク・トラヒックのバースト性ファクタ、およびアップリンク・パケットの消失レートを、前記リモート・ホストの少なくとも1つに対して測定するステップと、 前記基地局の前記リモート・ホストの少なくとも1つから、測定されたダウンリンクビットレート、前記基地局からのダウンリンクトラヒックの測定されたバースト性ファクタ、および測定されたダウンリンクパケットの消失レートを受信するステップと、 前記基地局において、前記リモート・ホストの平均およびピークビットレート、トラヒックの前記バースト性ファクタ、および前記リモート・ホストの前記パケットの消失レートに基づいて、前記リモート・ホストごとに等価バンド幅を計算するステップと、 すべての既に許可されたコネクションに対してすべての等価バンド幅に基づいて、許可できるコネクションの等価な数を計算するステップと、 前記新しいコネクションは許可されるときでも、前記すべての既に許可されたコネクションのサービスの品質を判定するステップと、 前記リモート・ホストの前記既に許可されたコネクションの前記サービスの品質が維持できる場合か、または前記既に許可されたコネクションの少なくとも1つが前記既に許可されたコネクションの前記サービスの品質を損なうことなく、切断でき、かつ前記既に許可されたコネクションの他のすべてへの前記新しいコネクションによって置き換えることができる場合にのみ前記新しいコネクションを許可するステップとを組み合わせて含む方法。
Independent claims6
429 paragraphs in 1 section, as filed
Description: TECHNICAL FIELD [Detailed description of the invention]
【0001】
[Technical field to which the invention belongs]
The present invention provides medium access control (MAC) known as "on-demand multiple access fair queuing" for applications in wireless communication network systems. Regarding the protocol. In particular, the present invention relates to methods for allowing new remote connections to base stations based on measured quantities in time-division and frequency-division half-duplex and full-duplex multiplex access wireless networks. ..
【0002】
[Problems to be Solved by Conventional Techniques and Inventions]
Wireless services such as cellular voice and data and wireless LAN are expected to grow rapidly in the future. Third-generation wireless networks designed to carry multimedia traffic are currently being actively researched, and their main goal is seamless communication, bandwidth, without restrictions on location or mobility. To provide high availability and guaranteed quality of service (QoS).
【0003】
Figure 1 shows a conventional wired network for data exchange. This figure shows three existing business entities, whose cooperating devices typically now provide remote Internet access through a modem to the user's computer. It is used for. The user's computer 2 and the user's modem 4 make up the end system. The first business entity shown in Figure 1 is a telephone company (telco) that owns and operates a dial-call simple old-fashioned telephone system (POTS) or an integrated services digital network (ISDN). .. telco provides a transmission medium in the form of a public switched telephone network (PSTN) 6 that allows bits or packets to flow between the user and two other business entities.
【0004】
The second business entity shown in Figure 1 is an Internet Service Provider (ISP). The ISP employs one or more Point of Presence (POP) 8 within its service area, manages it, and end users connect to it for network services. .. An ISP usually establishes a POP within each major calling area, hoping that there will be subscribers to that ISP. POP8 converts message traffic from PSTN6 into a digital format carried on the intranet backbone 10. Intranet Backbone 10 is owned by ISP or MCI It is either leased from an intranet backbone provider such as Inc. ISPs typically lease partial or full T1 or T3 lines from the telco for connections to the PSTN. The POP8 and ISP media data centers 14 are connected together on the backbone 10 of the intranet through router 12A. Data center 14 houses the ISP's web server, mail server, accounting, and registration server, allowing the ISP to provide web content, email, and web hosting services to end users. To. Future value-added services can be added by adopting additional types of servers within the data center 14. The ISP maintains router 12A to connect the public internet backbone 20. In existing models for remote access, end users typically have service relationships with both their respective telco and their respective ISPs, and are usually charged separately from each. End users access their ISP by dialing the nearest POP and by running a communication protocol known as the Internet Engineering Task Force (IETF) Point-to-Point Protocol (PPP). And access the public internet 20 through that ISP.
【0005】
The third business entity shown in Figure 1 is a private company that owns and runs its own private intranet 18 accessed through Router 12B. Enterprise employees make POTS / ISDN calls to the enterprise remote access server 16 and remotely to the enterprise network 18 by running the IETF PPP protocol (for example, from their own home or on the street). Can be accessed (while in). When accessing the enterprise, the end user only pays for the cost of connecting to the enterprise's remote access server 16. ISP is not involved. The private company maintains Router 12B to connect end users to either the company's intranet 18 or the public Internet 20.
【0006】
End users are now paying telco both the cost of making a call and the cost of a telephone line to their home. The end user must also pay the ISP to access the ISP's networks and services. Internet service providers now offer Internet access services, web connectivity services, email services, content hosting services, and roaming to end users. Due to the lack of feature and price-based market segmentation and low margins, ISPs are looking for value-added services to improve their margins. In the short term, device vendors will have faster access for ISPs, virtual private networking (the ability to securely use public networks as private networks and the ability to connect to intranets), roaming consortiums, push pushes. We want to be able to provide solutions to ISPs that enable us to provide the quality of technology and specific services. In the long run, it is desirable to provide voice over the Internet and mobility. At that time, ISPs will be able to use these value-added services to escape the tight constraints of low margins. Many of these added values fall into the category of network services and can only be provided through the infrastructure equipment of the network. Other value-added services fall into the category of application services that require support from the network infrastructure, while others still do not require support from the network infrastructure. In particular, services such as faster access, virtual private networks, roaming, mobility, voice, quality of service, and QoS-based accounting all require sophisticated network infrastructure.
【0007】
Wireless communication networks have the advantage of being able to extend the reach of wired networks. However, the bandwidth gained at the frequencies of wireless networks often lags behind what is available in wired networks. Wired broadband systems, such as Asynchronous Transfer Mode (ATM), have different QoS (for example, constant bit rate (CBR), variable bit rate (VBR), and available bits) for advanced support in multimedia applications. Rate (ABR)) services can be provided. It is hoped that the service will be extended to wireless networks. Therefore, research on merging ATMs with wireless networks is currently underway at many research institutes and laboratories. Many basic issues that affect everything from the access layer to the transport layer are being studied. In addition to using ATM as the mode of transmission in the air interface of wireless networks, ATM is also being considered for the wired infrastructure of cellular systems. Such wired infrastructure will be able to support multiple access air interface technologies (eg, CDMA, TDMA, etc.).
【0008】
In wireless networks that support multimedia traffic, efficient channel access protocols need to maximize the use of restricted radio spectra while still supporting the quality requirements of all traffic services. Several well-known channel access protocols, such as Slotted Aloha and PRMA, are currently used by wireless data systems. Slotted Aloha is a simple protocol, but its theoretical capacity is only 0.37 because it does not try to avoid or resolve conflicts between data users. Moreover, slotted aloha is not suitable for efficient transmission of variable length packets.
【0009】
Reservation-based protocols attempt to avoid and resolve conflicts by dynamically allocating channel bandwidth to users who need to send packets. Typically, in such a protocol, the channel is divided into slots grouped into frames of N slots. One slot can be further subdivided into k mini-slots. Usually N<sub>1</sub>One slot is used for reservation purposes and the remaining NN<sub>1</sub>The slots are data slots. For users who need to send packets, M = N<sub>1</sub>* Send a reserved send request packet in one of the k minislots. If the reservation request packet is successful, a number of data slots are allocated to the user until the user or base station releases the reservation. If the reservation request packet is unsuccessful, the user resends it using conflict resolution until the reservation request is successfully transmitted.
【0010】
A Broadband Multiple Access Protocol for STMs, Broadband Multiple Access Protocols for ATMs, and Variable Length Data Services in Hybrid Fiber-Coaxial Networks by Doshi et al. STM, ATM, and Variable Length Data Services on Hybrid Fiber-Coax networks), Bell Labs Technical Journal, Summer Proposed in 1996, pages 36-65. Although sharing many of the challenges associated with wireless environments, this protocol handles retransmitting over error-prone wireless links and establishing the transmission power level required to ensure correct packet delivery. It does not completely address the unique problems encountered in the design of wireless access schemes. This method proposes the idea of competing reserved slots, but it does not provide a flexible method that can dynamically change the number of competing slots based on queue size information.
【0011】
Karol et al. Have proposed a "Distributed-Queuing Request Update Multiple Access" protocol (DQRUMA) [Karol et al. "Efficient for Wireless Packet (ATM) Networks" An efficient demand-assignment multiple access protocol for wireless packet (ATM) networks, Wireless Networks 1, pp. 267-279, 1995]. This wireless access scheme takes advantage of the success rate of reserved slot competition in the previous round to allow new users to compete for bandwidth during the conflict resolution period, or to adjust the backoff time. Can't. Also, this method does not utilize fair queuing techniques and therefore does not use service tags to fairly allocate bandwidth among competing sources.
【0012】
One important subject in the design of channel access protocols is the selection of scheduling techniques used to set the order of transmission of uplink and uplink packets. Many schedulers, all variants of fair queuing, have been proposed for wired networks [for example, SJ Golestani's "Self-clocking fair queuing scheme for wideband applications" ( A Self-Clocked Fair Queuing Scheme For Broadband Applications), Proceedings of IEEE Infocom, 1994; Parekh and Gallagher's "Generalized Processor Sharing Method for Flow Control in Integrated Services Networks: Single Node (A Generalized Processor Sharing Approach To Flow Control In Integrated Services Networks: The Single Node Case), IEEE / ACM Transactions On Networking, 1 (3): pp. 344-357, June 1993; L. Chang's "Virtual Clock Algorithm", Proceedings of ACM Symposium, See pages 1224-1231, 1992]. All of these have the effect of providing access to bandwidth sharing as if each subclass owns its own server at its given rate.
【0013】
The weighted fair queuing scheme of Parek and Garaga is difficult to implement, so a self-clocking fair queuing scheme (SCFQ) was proposed by Gorstani. For SCFQ, the service tag is calculated as follows:
[Number 1]
<img file="JPP3477086B2_D0001.tif" />Where ^ u (t) is the service tag of the packet being serviced at time t, F<sup>i</sup><sub>k</sub>Is F for all k<sup>o o</sup><sub>k</sub>Service tag for the i-th packet from class k with = 0, L<sup>i</sup><sub>k</sub>Is the length of the i-th packet of class k, r<sub>k</sub>Is the relative weight assigned to class k, and a<sup>i</sup><sub>k</sub>Is the arrival time of the i-th packet of class k. The packets are then serviced in the order of the values of these tags. Gorstani's algorithm is designed for wired networks, but it must be modified to work in a wireless environment. In particular, Gorstani's algorithm handles transmission scheduling when the server (base station) is in a remote location and does not have complete information about queue size, or it handles the retransmission of lost packets. Does not deal with.
【0014】
Lu et al. (University of Illinois) have proposed an "idealized weighted fair queuing" algorithm [Lu et al. "Fair Scheduling in Wireless Packet Networks" Sigcom '97]. It is designed to meet the special needs of wireless networks. This method requires complete knowledge of the state of the channel (ie, good or bad), which is not generally available in a real network. It also does not change the service tag of packets that do not send successfully, the process of retransmission is complex, and drops packets from lazy flows, not just when there is buffer overflow.
【0015】
In A Distributed Self-Clocked Fair Queuing Architecture For Wireless ATM Networks, 1997 International Symposium on Personal Indoor and Mobile Radio Communications, by R. Kautz Another wireless access scheme proposed in uses a polling system instead of the reservation and piggybacked (piggyback) reservation method. The performance of the polling method is generally inferior to that of the reserved access method in terms of delay and bandwidth utilization. In addition, the Kautz method changes the value of the service tag only for packets that are transmitted and result in an error, thus affecting QoS at all remotes. This is because the retransmission of the lost packet delays all remote packages.
【0016】
[Means for solving problems]
The present invention is a method of on-demand multiple access (ODMA) with fair queuing (FQ) service discipline (called ODMAFQ) to effectively utilize the limited bandwidth available in a wireless network. This is one aspect. In this method, bursty sources send channel access packets to reserve bandwidth for future transmissions whenever one packet arrives on an empty queue, while constant bits. -Rate sources are made to conflict only once when setting up a connection. Distributed self-clocking fair queuing service discipline is used to determine the transmission order of various uplink sources and can provide a variety of QoS.
【0017】
When a remote host requests a connection to a base station, the base station must decide whether to allow the new connection. The authorization control technique can be as simple as allowing any new connection request if the total number of allowed connections is less than the maximum, but such a simple authorization. Control techniques cannot guarantee the quality of service to all already authorized users and cannot result in the efficient use of bandwidth. Therefore, other permission control techniques may be better than simple methods, and it is also possible to utilize a combination of several methods.
【0018】
In the method of permission control of the present invention, the base station can determine whether the quality of service of an already permitted connection may not be satisfied by permitting the new connection. Measure and calculate performance measures. If the quality of service of all allowed connections is maintained even after allowing a new connection, the new connection is allowed, otherwise the new connection request is denied.
【0019】
In one preferred embodiment, each connection request specifies the required average bit rate and traffic burst factor. The base station collects information about the number of bytes sent by each connection in both directions over a period of time, and measures the burstability factor in both directions for the traffic of that connection. Based on this measured information, the base station can determine the average bit rate of the connections and the burstability factor of each connection. The base station then calculates the equivalent number of allowed connections. When a new connection request arrives, the base station calculates whether the new equivalent number of allowed connections after allowing the new connection exceeds the threshold. If the threshold is exceeded, the connection request is rejected, otherwise it is accepted. In one embodiment, the base station can optionally disconnect one or more of the connections already allowed with lower priority, in which case a new connection with higher priority will be created. It will be allowed without compromising the quality of service for the remaining already allowed connections.
【0020】
The quantity measured can be various measures related to jamming. In this embodiment, the base station measures the frame error rate (FER) based on the measured interference to know if the new connection should be allowed. The uplink frame error rate, average uplink bit rate, its uplink traffic burst factor, and packet loss rate are constantly measured at the base station for each remote host. .. The downlink frame error rate, the average downlink bit rate, its downlink traffic burst factor, and the packet loss rate are constantly measured at each remote host already allowed, and then The FER is sent from each remote host to the base station. Alternatively, the average downlink bit rate, downlink traffic burst factor, and packet loss rate can also be sent from each remote host to that base station. Equivalent bandwidth is calculated for each remote host at the base station based on the average and peak bit rates of the connection, the burstability factor of the traffic, and the packet loss rate of each connection. These calculations are then used by the base station to calculate the equivalent number of connections already allowed. When a new connection is requested, the base station considers the effects of the average rate and packet loss rate required by the requested connection and services all allowed connections based on the equivalent bandwidth. Calculates whether the quality of is maintained even if the new connection is allowed. If QoS can be maintained, the new connection is allowed, otherwise the new connection is denied permission.
【0021】
A general object of the present invention is to provide bandwidth to a remote host on demand in a wireless network. One specific object of the present invention is a new remote host while efficiently sharing the limited bandwidth available in a wireless network and maintaining the quality of service to an already authorized remote host. To provide a measured amount-based method in wireless communication to allow a device to communicate with a base station.
【0022】
BEST MODE FOR CARRYING OUT THE INVENTION
As explained earlier, one object of the invention is to provide a wireless packet-switched data network for end users who bypass the public switched telephone network, and to remote users of the wireless network. It is to provide a roaming function. These and other objectives are achieved in wireless data networks that include home mobile exchange centers, foreign mobile exchange centers, base stations (access points) and end users. The Home Mobile Exchange Center includes a home registration server and home interworking capabilities. The Foreign Mobile Exchange Center includes an in-service registration server and an in-service interworking function. The base station includes a proxy registration agent. The end user's modem contains a user registration agent. The user registration agent is bound to the proxy registration agent, the proxy registration agent is connected to the in-service registration server, and the in-service registration server is home registration. -Connected to the server.
【0023】
The proxy registration agent includes a module for sending a notice containing a care of address when it receives a request from a user registration agent. In addition to the module for sending this registration request to the proxy registration agent, the user registration agent also includes the user's identity and care of address in the registration request upon receipt of the announcement. Includes modules for embedding. The proxy registration agent further includes a module for forwarding any registration request received from any user to a serviced registration server.
【0024】
The in-service registration server encloses the foreign directory module for determining the home registration server's address, the registration request, the identity information of the in-service registration server, and the enclosed registration. A module for incorporating a registration request into an access request within a radius when the address of the home registration server is determined, and for sending an access request within that radius to the home registration server. Includes modules. The home registration server is the home directory module for authenticating the identity of the registration server in service, from access requests within the radius when the identity of the registration server in service is authenticated. Includes a module for making interworking function (IWF) requests and a module for sending the interworking request to the home interworking function.
【0025】
As seen in the network embodiments utilizing the present invention shown in FIG. 2, the end system (remote host) 232 (eg, a portable Windows 95 personal computer) has an external or internal modem. Connect to wireless network 230 via. These modems allow the end system 232 to send and receive medium access control (MAC) frames over airlink 234. When used, an external modem can be attached to the PC or other end system 232 via a wired or wireless link. External modems are generally fixed and can be co-located with roof-top mount directional antennas. The external modem can be connected to the user's PC using any suitable linking method, such as general purpose serial bus, parallel port, infrared, 802.3 or ISM wireless link. The internal modem is preferably a PCMCIA card that sends and receives MAC frames over the airlink and is plugged into the backplane of the laptop using a small omnidirectional antenna.
【0026】
Wide area radio coverage is provided by base station (access point) 236. The range of coverage provided by base station 236 depends on factors such as link budget and capacity. Base stations are typically installed inside cell sites by providers of personal communications services (PSC) wireless services. Base station 236 multiplexes end-system traffic from their respective coverage areas to the system's mobile exchange center (MCS) 240 and provides it over a wired or wireless microwave backhaul network 238.
【0027】
At the mobile exchange center 240, the packet data interworking function (IWF) 252 terminates the radio protocol for this network. IP router 242 connects MSC240 to public internet 244, private internet 246, or to internet service provider 247. The accounting and directory server 248 in the MSC240 stores accounting data and directory information. The element management server 250 manages the equipment. Its equipment includes base stations, IWF, and accounting / directory server 248. Accounting server 248 collects accounting data on behalf of the user and sends the data to the service provider's billing system. In one preferred embodiment, the interface supported by accounting server 248 is a TCP / IP (Transfer Control Protocol / Internet Protocol) transport to a billing system (not shown in Figure 2). Above the American Management Association (American) Submit the accounting information in the format of a Management Association (AMA) billing record.
【0028】
In a typical wireless network in which the present invention is utilized, each cell has one base station and several remote hosts (nodes), with or without additional wired hosts. The remote host / node can include any device capable of communicating with the base station over a wireless link. Fixed-length packets arrive at remote hosts (remote) at a constant rate (CBR traffic) or according to various bursty random processes. The packet is buffered at the remote until it is uplinked to the base station according to the channel's access scheme. The base station broadcasts downlink packets destined for one or more remotes inside the cell. Uplink and downlink communications are time-divisioned on a single frequency channel to allow dynamic sharing of uplink and downlink bandwidth. The scheme of the present invention can also be used for frequency division multiplexing (FDHD) and frequency division multiplexing (FDFD) systems. Base stations use a variant of Gorstani's self-clocking fair queuing algorithm to schedule the order of packet transmissions from both remote hosts (remote queues) and wired hosts (local queues).
【0029】
The on-demand multiplex access fair queuing (ODMAFQ) method of the present invention is a time slot type system in which an access request channel and a packet transmission channel are formed on a slot-by-slot basis. The length of the time slot is chosen based on the particular system implemented. As an example, this can be equal to the time required to send the payload of one ATM cell plus radio and MAC specific headers. Uplink and downlink traffic multiplex is based on Time Division Duplex (TDD) for TDD and FDHD systems. The remote host that has the packet to send sends an access request to the base station via the request channel. The exact way each remote makes such a request depends on whether the remote's traffic is bursty or has a constant bit rate.
【0030】
Transmission on the request channel is based on multiple access. Upon receiving a successful access request, the base station updates the corresponding entry in the request table. The request table contains one entry for each of all remote and wired hosts in that cell. Each entry contains a remote / wired host identification tag and related fields that contain a service tag, and if the tag value is -1, then that particular host has no other packets to send. It is used as a preference to indicate. Wired hosts are local to the base station, so they do not need to go through the process of request access.
【0031】
The base station schedules its uplink and downlink traffic transmissions, and in addition to the current bandwidth needs of all supported hosts, bandwidth is based on traffic characteristics and QoS requirements. Assign dynamically. To schedule the order in which packets are sent from a host by the remote queue information sent to that base station through the current queue information and reservation requests for all wired hosts that are always known to the base station. Service tags are used. The reservation request is either piggybacked over an already scheduled uplink transmission or sent to the base station via the request access channel in contention mode.
【0032】
One embodiment of the ODMAFQ scheme is shown in FIG. Remote host 2210 requests access to base station 2212 via request access channel 2220. A successful request is sent to the scheduler 2230, which informs both the remote 2210 and the wired host 2240 of 2232 when to send each. At that time, a particular remote 2210 sends 2234 packets over transmit channel 2250. If there are additional packets to be sent to that remote, it piggybacks over the transmission channel 2250 with a reservation request for the next packet on the current packet 2234 being sent as 2252. In this way, the need to send request 2212 for the next packet over request access channel 2220 in contention mode is avoided.
【0033】
As shown in the flowchart of FIG. 23, when a packet arrives at a remote with an empty buffer queue at 2310, the source is determined to be bursty at 2314, i.e. relatively continuous. When providing a high packet or other data flow, the remote makes an access request at 2320 and informs the base station (access point) of the arrival rate of its packet and the duration of the conflict. If an acknowledgment (ACK) is determined in 2324 and a transmit permission is determined in 2328 from the base station, the remote is in 2330 the first packet in the time slot specified in the transmit permission. To send. At 2328, the base station continues to provide transmission permissions remotely until the duration of the connection expires at 2332. You only need to make one access request for the entire duration of the connection.
【0034】
In contrast, when a packet arrives at a remote with an empty buffer queue at 2310 and it is determined in 2314 that the packet is from a bursty source, i.e. the packet from that source or other. If the rate of the data flow is very discontinuous, the remote makes an access request over the uplink request access (RA) channel in conflict mode on the 2350. The channel consists of multiple reserved minislots. A remote access request includes the identity assigned in the remote invocation setup or invocation handoff. When the base station successfully receives a remote send request, it updates the corresponding entry in the request table, indicating that the remote with that identity has a packet to send, and Then broadcast the identity on the downlink channel. The remote waits for ACK reception at 2354 and transmission permission at 2358. When sending a packet, the remote determines at 2362 if there are any additional packets left in the queue. If not left, the packet is sent normally at 2366. However, if there are other packets waiting to be sent at 2362, the remote will place a bandwidth reservation request for the next packet on top of the current packet (piggyback) so that it will be sent at 2370. This piggyback acts as a conflict-free reservation request, so only remote arriving packets with empty buffers trigger the remote to send an access request.
【0035】
3-9D are described herein according to the principles of the present invention, including extensions to frequency division multiplexing (FDHD) mode and frequency division multiplexing transmission (FDFD) mode. -A descriptive example of a frame format for a medium access control (MAC) scheme for a system. Thus, the on-demand multiplex access fair queuing (ODMAFQ) scheme described with respect to FIG. 23 can be used to provide network control in both frequency division half-duplex and full-duplex transmission modes. The frame formats shown here are only examples, and formats known to those with ordinary skill in the art of the present invention, and formats suitable for wireless transmission are invented. It is in the range of.
【0036】
In both FDHD and FDFD modes, the access point (AP) sends to the remote host at downlink frequency f1, while remote mode sends to the AP at uplink frequency f2. Figures 3 and 4 show the downlink and uplink frame structures for FDHD, respectively. Note that the length of downlink and uplink transmission times does not have to be the same. For example, if traffic characterization indicates that a ratio of downlink to uplink transmission time ratio of 4: 1 (downlink transmission is longer than uplink transmission) is optimal, then downlink. Optimal performance is obtained when 4 x ms is assigned to the frame size of and x ms is assigned to the frame size of the uplink.
【0037】
As shown in FIG. 3, the downlink frame for the FDHD scheme of the present invention may include physical layer overhead. They are, for example, guard and / or preamble bit 310 (which can be used as a synchronization bit), medium access control (MAC) header 312, various control messages 314, such as some beacon messages, Send permission 320, minislot information 350 for the next uplink frame, and send schedule 322, knowledge (ACK) for reserving the minislot in the previous uplink frame, in the previous uplink frame 330 There are headers for transmitted data, broadcast / multicast data message 360, unicast data message 380, and frame check sequence (FCS) 355 for each preceding data message. For example, a downlink frame can consist only of transmit permissions, knowledge for minislot reservations, and unicast messages.
【0038】
Some control messages are preferably part of broadcast message 360, which can include load measures, information about reserved minislots, flow control information, knowledge, and power management parameters. The load measure information can be as simple as the number of remote nodes registered for that AP. Alternatively, it may be more advanced, such as an equivalent number of active remote nodes. Load measures can be used for permit control and load balancing between APs. The minislot information describes the number of reserved minislots that exist and their locations, if any, in the next uplink frame. Flow control information includes connection cookies (identities) and Xon / Xoff instructions.
【0039】
The acknowledgement 340 for uplink unicast traffic may be as simple as the acknowledgement bit that is part of the broadcast message. Alternatively, it may be a more sophisticated one, for example another unicast message that specifies the identity of the connection and the sequence number of the message to be acknowledged. In the former case, if the uplink transmission uses a frame structure with N fixed basic slots, a maximum of N acknowledge bits are required. In the latter case, each message must have a separate frame check sequence (FCS). Note that due to the "hidden terminal problem", all transmitted frames need to be acknowledged.
【0040】
Data slot 380 contains transmissions from multiple remote nodes. Transmissions from each remote node include guard bits, preamble bits, frame control bits, knowledgement, and / or data messages. One of the frame control bits is the "more" bit, which indicates that the remote node still has more data to send. Instead of just using "more", you can specifically specify the number of bytes left to be sent, or the number of fixed-size packets.
【0041】
As shown in Figure 4, FDHD uplink frames typically consist of a conflict period 410 and a conflict-free period 415. The conflict period 410 includes one or more conflict slots, and each conflict slot can be either a conflict data slot 420 or a conflict reservation slot 422. The conflict-free period 415 consists of an acknowledgement 440 for the previous downlink slot and multiple data slots 480 and 486. If desired, these competing slots 420 and 422 can be made to be evenly distributed throughout the frame rather than being grouped together. Each competing reserved slot 422 can be further divided into k subslots 430, which are called reserved minislots. Each minislot 430 is long enough to contain the identity of one remote node, typically about 30 bytes. The conflict slot 420 can also be used as a data slot for transmitting small data packets. The conflict-free period 415 can include a pure ACK frame 440, a pure data frame 480, and / or a combination of frames 486 containing both parts of the data 488 and ACK 490.
【0042】
The number of minislots 430 is subject to change dynamically. For example, if there are k minislots in the conflict reserved slot 422 and there are a total of N conflicting slots, then N1 of them is the reserved slot 422, which contains a total of N1 * k minislots. , The remaining (N-N1) slots are currently competing data slots. If the system has a minimum and maximum number of reserved minislots, the number of reserved minislots available dynamically changes based on the percentage of idle minislots and the total uplink queue length. can do. Several methods for dynamically changing the number of minislots will be described later in connection with FIGS. 12A-12D.
【0043】
To assign different priorities to remote nodes that are trying to gain access to the system, M<sub>1</sub>= N1 * k minislots (where N1 is the number of competing reserved slots) can be divided into various groups. For example, a group of remote nodes with MAC addresses within a range is M<sub>2</sub>Up to 3 mini slots (here M<sub>2</sub><M<sub>1</sub>) Is only allowed to be randomly accessed, while the higher priority group of remote nodes whose MAC address is within another range is M<sub>1</sub>You can allow up to a number of mini-slots to be accessed randomly. Alternatively, the priority class can be assigned to a node based on the identity of the connection rather than the MAC address. The priority assignment function is especially useful. For example, it is particularly useful for institutions that require an urgent response, such as hospital or police personnel, and can be achieved by providing a wireless modem with a higher access priority than a regular wireless modem. This feature can also be sold as a class of service to customers who may charge higher for higher access priorities.
【0044】
As shown in FIG. 5, uplink frames 502 and 512 in frequency division multiplexing (FDFD) mode are synchronized with downlink frames 562 and 572. As can be seen in Figure 5, the uplink frame 502 is shown as seen from the wireless modem, the uplink frame 512 is shown as seen from the AP, and the downlink 562 is shown as seen from the AP. It is shown as seen from, and the downlink frame 572 is shown as seen from the wireless modem. In Figure 5, the AP previously sent a downlink frame n to the wireless modem, which has a propagation delay time T.<sub>p</sub>Is received after. In response, the end system processing time T<sub>cpe</sub>After that, the wireless modem sends an uplink frame n 504, which is propagated by the AP as 514 with a delay time T.<sub>p</sub>Received after 520. In the meantime, the AP has already started transmitting downlink frame n + 1 564.
【0045】
Uplink so that the modem at each remote node has enough time to work on the information in the transmit permission (for example, after receiving downlink frame n and immediately following the uplink frame). Link transmission time offset O<sub>u</sub>Is stipulated. Here the processing time of the end system in the wireless modem, T<sub>cpe</sub> 550 is O<sub>u</sub>It is assumed to be smaller. Therefore, uplink frame n + 1 506 from a radio node is O after the last bit of the (n + 1) th (n + 1) th of downlink frame 574 from the AP has been received at that node.<sub>u</sub>Starts after the transmission time of. Offset O<sub>u</sub>And the frame duration fd, for example, before the start of the next uplink frame, the modem receives and processes conflict slot feedback so that the send permission is received from the previous downlink frame. Need to be selected. Frame size fd is fd 2T<sub>p</sub>+ T<sub>AP</sub>+ T<sub>cpe</sub>+ T<sub>R</sub>Is selected to be. Here T<sub>p</sub> 520 is the delay time, T<sub>AP</sub> 540 is AP processing time, T<sub>cpe</sub> 550 is the end system processing time, T<sub>R</sub> 530 is the transmission time of the transmission permission, and O<sub>u</sub> T<sub>cpe</sub>Is.
【0046】
Therefore, in FIG. 5, when the wireless modem starts transmitting uplink frame n 504, the AP is already transmitting downlink frame n + 1 564. The wireless modem is already receiving 514 downlink frames n + 1 when it begins transmitting uplink frames n 504. The AP sends 544 uplink frame n before it starts transmitting downlink frame n + 2 566.<sub>R</sub> 530 + T<sub>AP</sub> Receive 544 uplink frames 540 hours ago. Downlink frame n + 1566 propagated delay time T by wireless modem<sub>p</sub> Received as 576 after 520. The wireless modem processes the uplink frame n + 1 506 in the end system with a processing time of T.<sub>cpe</sub> Sent after 550, and it propagates delay time T as 516 in AP<sub>p</sub> Received only after 520. Similar synchronization occurs for transmit 508 and receive 518 on uplink frame n + 2 and transmit 568 and receive 578 on downlink frame n + 3.
【0047】
The structure of the basic downlink MAC frame is a frame composed of several subframes. You can also define a superframe made up of an integer number of frames. The duration of the frame depends on the actual physical transmission rate. For example, it is fixed at 2ms and the number of subframes contained in one frame can change. In the absence of strict conditions, the length of the subframe can be varied. Otherwise, in order to meet the severe delay time conditions of that source, each frame is divided into a synchronous transfer area (STR) and an asynchronous transfer area (ATR), and sources with such delay time conditions. Should be able to receive a fixed bandwidth within the time of each frame. Each area can be further subdivided into basic slots.
【0048】
FIG. 6A shows a specific example of the frame format of the downlink broadcast subframe of the general MAC layer according to the present invention. The MAC frame of this example, 17 bytes of a MAC header 620, a frame body 622, and 2 or 4 bytes of frame check may click sequence (FCS) 624, overhead 601 (guard and the physical layer in addition to this There is a preamble bit). The MAC header 620 typically contains at least a frame control bit, source and destination MAC addresses, and frame duration. Specific examples of the MAC header in Figure 6A are 1-byte frame control (FC) field 602, 2-byte frame duration field 630, 6-byte source MAC address 632, 6-byte destination MAC address 634, and 2. It contains a byte sequence control field 636, which is subdivided into a 12-bit sequence number and a 4-bit fragment number. Obviously, any other MAC format can be used, depending on the type of handoff required. The frame format is preferably implemented in a way that makes the system most efficient.
【0049】
The 1-byte frame control field 602 of the example in Figure 6A is a 2-bit protocol version identifier 604, a 1-bit "more fragment" indicator 606, and a 1-bit "retransmission". Indicator 608, 1-bit Xon / Xoff signal 616, 1-bit encryption on / off flag (WEP) 614, 1-bit "more data" indicator 612, and power. Includes 1-bit flag for management, on / off 610. If all of these fields are not needed, any remaining bits can be reserved for future use. Other implementations are, of course, feasible and are considered by the inventor.
【0050】
The format of the broadcast or multicast downlink frame according to the present invention is shown in Figure 6B. In this particular example of FIG. 6B, frame body 622 has beacon message 640, knowledge for the previous uplink reserved minislot 626, transmit permission 650, transmit schedule 660, broadcast / multicast message 670, and previous. Includes knowledge for uplink data 628. The frame body 622 is followed by the frame sequence 624, which is preceded by the MAC header 620, which is the 1-byte frame control (FC) field 602, the 2-byte frame duration field 630, 6 bytes. It consists of the source MAC address 632, the 6-byte destination MAC address 634, and the 2-byte sequence control field 636.
【0051】
Figure 6C shows the format of Beacon Message 640 in Figure 6B (314 in Figure 3). Beacon message body 614 is generally the message length field, AP identity (referred to as ESS-ID and BSS-ID in the Institute of Electrical and Electronics Engineers (IEEE) standard 802.11), and transmission power level. Includes Beacon Interval, Timestamp, Load Measure, Optional FCS and Functional Information. Beacon message feature information includes FDFD / FDHD options, maximum number of users allowed, maximum payload size, and security options (whether encryption is used or any encryption format is supported). Can include information such as), maximum number of retransmissions, downlink / uplink transmission time ratio, uplink frame size, minislot size, quality of service (QoS) features, and so on. If there is load measure information, it generally includes the number of associated remote nodes. Beacon message body 641 is preceded by the type 642 "control" and subtype 644 "beacon" fields.
【0052】
FIG. 6D shows the transmission permission format 650 (320 in FIG. 3) of the specific example of FIG. 6B. The transmit permission body 651 is preceded by the Type 652 "Control" and subtype 654 "Transmit Permission" fields. In this embodiment, the send permission body 651 contains a message length indicator 655 and a send permission number 656. Each 3-byte transmit permission 656 contains the identity of the remote node or connection 657, the start time or slot 658, and the duration of transmission 659 (end slot) for which the remote node or connection is allowed. In the example shown, the message length 655 is 6 bytes, which means that two send permissions 656 follow. The first transmit permission 656 is for remote node 657 # 3, which can initiate transmission in start slot 658 # 1 and transmit to end slot 659 # 2. The second transmit permission 656 is for remote node 657 # 5, which initiates transmission in start slot 658 # 3 and end slot 659. You can send up to # 5. Different "type" and "subtype" labels can be used for the transmit permission of the other wireless modem to which the AP sends both downlink unicast data and transmit permission. Subframes that combine transmit permissions and schedules are preferably sent after a pure transmit permit and before any pure transmit schedule.
【0053】
FIG. 6E shows the format of the transmission schedule of the specific example of FIG. 6B. An optional transmit schedule 661 (322 in Figure 3) allows remote nodes or connections associated with that AP to power down if the data to be sent to them was not scheduled. .. The transmission schedule body 661 is preceded by the type 662 type "control" and subtype 664 "transmission schedule" fields. The transmission schedule 661 can take one of two formats. Its first form is simple, for example, 12 bitmap formats containing a "1" to indicate the existence of unicast data for that remote node or connection, for example "011000000010". Show that the frame contains unicast data for the second, third, and eleventh of the remote nodes in. The second possible form is more sophisticated, for example, the ID or start time of the remote node or connection, and the duration that the node is allowed to send (included in the send permission). Contains the same data as the one in.
【0054】
Figure 6F shows the broadcast or multicast payload format 670 (360 in Figure 3) of the example in Figure 6B. Body 671 of the payload can contain various data messages or control information, preceded by type field 672 and subtype field 674. These fields change according to the contents of body 671 of the payload. For example, if body 671 of the payload contains the number of competing minislots and their respective positions, its type 674 is "control" and subtype 672 is "competitive minislot information", while the payload If body 671 contains a broadcast message from a wireless hub, type 672 is "data" and subtype 672 is also "data".
【0055】
FIG. 7A shows a specific example of the frame format of the downlink unicast subframe 700 according to the present invention. Examples of unicast subframes are control messages, such as related response frames and flow control request frames with knowledge and / or "more data" information, and data messages. "More The "data" information can be as simple as a bit in a subfield of frame control 702 in the MAC header, or a more specific representation such as the number of bytes remaining to be sent. Can be. The example downlink unicast subframe 700 shown in Figure 7A has a 1-byte frame control subfield 702, a 2-byte frame duration field 704, a 6-byte source MAC address 706, and 6 bytes. Includes a destination MAC address of 708, and a MAC header 701 containing a 2-byte sequence control field 710. The rest of the downlink unicast subframe 700 consists of a unicast data body 720 and a frame check sequence (FCS) 712.
【0056】
FIG. 7B shows a specific example of the flow control frame format for the downlink unicast data subframe according to the present invention. In this particular example of Figure 7B, body 720 of unicast data includes type field 722 "control" and subtype field 724 "flow control", followed by competing identity (CC) field 726. Data field 730 follows, which contains the Xon / Xoff bits.
【0057】
FIG. 7C shows one specific example of a data frame format for downlink unicast data subframes according to the present invention. In the embodiment of Figure 7C, the unicast data body 720 contains the following fields: one or more of the following fields: data 744, ACK746, and "more data" 748. If present, field 748 of more data can simply be a 1-bit flag or indicate the number of bytes remaining. If there is an ACK field 746, it can take the form of a sequence number or bitmap. The body of data 720 starts with the type field 740 "data" and then the values "data", "data + ACK", "data + ACK + More", or "ACK", depending on the configuration of the field. Subtype field 742, which can be included, follows.
【0058】
If there is only one connection per wireless modem, the unicast subframe will be added after the broadcast subframe, without overhead of the source MAC address field, as shown in Figure 7D. Can be concatenated so that The frame in Figure 7D consists of a unicast subframe 700 concatenated with a broadcast subframe 750. The broadcast subframe 750 is a 6-byte source MAC address 752, a 6-byte destination address 754, a 1-byte frame control subfield 756, a 2-byte frame duration field 758, a 2-byte sequence control field 760, and a broadcast. -Consists of data field 762 and frame check sequence (FCS) 764. Unicast subframe 700 has a 6-byte destination MAC address 708, a 1-byte frame control subfield 702, a 2-byte frame duration field 704, a 2-byte sequence control field 710, a type field 722, and a subtype field. It consists of 724, connection identity 726, data field 730, and frame check sequence (FCS) 712. The frame control field 702 in the unicast subframe 700 is optional and is generally included when the bits in the frame control field are expected to change frequently. If the frame control field of a unicast subframe can be expected to be relatively static, it is often omitted except on special occasions where it is needed.
【0059】
For synchronization purposes, the AP can schedule downlink broadcast and unicast subframes so that the total transmission time of the broadcast and unicast subframes is inside the x ms frame structure. .. Where x is generally 2ms. However, in the case of uplink transmission, the uplink communication from the wireless modem is in burst mode, and there is a possibility of collision if two or more modems transmit within a given time window. Such collisions can only be detected in the AP. Also, each transmission burst must include some physical layer overhead.
【0060】
To take these factors into account, as shown in Figure 8A, for uplink transmission, which allows for better synchronization while providing the ability to achieve stringent delay conditions for synchronization traffic. The frame structure is defined. In the example shown, each uplink frame has a duration of x ms, of which 2 ms frames are used. Each x ms frame is subdivided into MAC header 808, synchronous transfer area (STR) 810, and asynchronous transfer area (ATR) 812. The synchronous transfer area 810 includes a data slot for carrying a CBR-like constant bit rate traffic. The length of each synchronous data slot in the STR810 of the concrete example of FIG. 8A is 27 bytes, of which 16 bytes are the payload field.
【0061】
As shown in Figure 8B, the asynchronous transfer area 812 is divided into N basic slots, each basic slot being a data slot for sending fixed size packets, for example, a cell in asynchronous transfer mode (ATM). Is equivalent to. Each base slot can be a competing reserved slot 820. In that case, it is further subdivided into k minislots 822. For example, the conflict reservation slot 820 can consist of 63 bytes, with each minislot 822 having 15 bytes. Further, the basic slot may be the data slot 824 or the reserved data slot 826.
【0062】
Each uplink frame in this example contains at least C competing slots available for pure contention. Of these C competing slots, N<sub>1</sub>Pieces are converted into reserved minislots for bandwidth reservations. Remaining CN<sub>1</sub>The conflict slots are data race slots 824 used to send short bursty messages that do not require reservations. C and N<sub>1</sub>May change. The AP can convert an unused conflicting data slot 824 to an additional reserved minislot 822. As explained earlier, the number of reserved minislots 822 can be fixed or dynamically variable. Also, reserved mini-slots can be grouped together within a portion of the frame or scattered throughout the frame. The AP broadcasts the number of competing slots available, the number of reserved minislots, and their position within the next uplink frame into its preceding downlink frame.
【0063】
Reserved data slot 826 in Figure 8B means either a fixed protocol data unit (PDU), such as an ATM PDU, or for variable length PDUs. The transmit burst for an ATM PDU contains a 53-byte ATM cell, MAC header, and physical layer header. One reserved data slot 826 is allocated for sending PDUs at each ATM. A transmit burst for a variable length (VL) PDU includes a variable payload plus the same overhead required for an ATM PDU. For variable length PDUs, it is desirable to minimize segmentation so that each AP allocates as much contiguous reserved data slots 826 as possible for VL PDUs.
【0064】
Conflicts are useless, so ideally there should be one field in the reserved send burst to request additional reserved data slots without going through the conflicts. When a scheduling discipline that uses queue length information (for example, a self-clocking fair queuing discipline) is used, the size of the next packet, or the number of remaining packets of fixed size, is from its source. Specified to reserve bandwidth for future data transfer. When first come-first serve, or round robin queuing discipline is used, the "more" bit in the frame control field of the MAC header can be used for the same purpose.
【0065】
In the uplink frame, if there is a constant bit rate transmission, it is in the slot position of the fixed synchronous transfer area (STR) determined during the conflict setup. For the new asynchronous transfer, the wireless node's modem randomly selects one of its available competing minislots 822 and requests bandwidth for the ATM / VL burst to be sent in subsequent frames. .. Defined as the arrival of a new packet on a connection where the "new" asynchronous transfer queue is empty. The AP then identifies the collision and notifies the wireless modem of its collision / success status via the knowledge field of the reserved minislot in the next downlink frame. A typical uplink frame is shown in Figure 8C. It contains a reserved minislot 822, an ACK832 for data received in the previous downlink frame, and an uplink reserved data field 826. The AP schedules ATM / VL slots for the next uplink frame as described in the implemented service (queuing) discipline. This information is sent to the modem at that remote node via a downlink frame (not shown, see Figure 3) in the transmit permission and schedule.
【0066】
Figure 8D shows an example of the frame format for the uplink frame reserved minislot 822 in Figure 8C. The frame contains a small MAC header 840 that contains only the source MAC address and a 2-byte sequence control field, followed by a connection identity (CC) field 842 and a frame check sequence (FCS) 844. ..
【0067】
Figure 8E shows an example of a frame format for a pure knowledge uplink frame. In this format, the full MAC header 848 is followed by type field 850 "data" and subtype field 852 "ACK", connection identity (CC) field 854, sequence number ACK field 856, and FCS858. ..
【0068】
Figure 8F shows an example of the frame format for pure data uplink unicast frames. In this format, the full MAC header 860 is followed by type field 862 "data" and subtype field 864 "data", connection identity (CC) field 854, data field 866, and FCS858. .. Figure 8G shows an example of a frame format for a combination of acknowledgement and data uplink frames. In this format, the full MAC header 870 is followed by type field 872 "data" and subtype field 874 "data + ACK", connection identity (CC) field 854, data field 876, sequence number ACK field. Followed by 878, and FCS858. Figure 8H shows an example of a frame format for a combination of knowledge, data, and "more" uplink frames. In this format, the full MAC header 880 is followed by type field 822 "data" and subtype field 884 "data + ACK + more", connection identity (CC) field 854, data field 886, sequence number. This is followed by ACK field 888, more data field 890, and FCS858.
【0069】
The above example employs the IEEE 802.11 standard to implement access control and provide special messages for permitting remote nodes to the network. As a specific example, in a system with an uplink bandwidth of 2.56 Mbps, the ramp up time is 4 μs, the 32 symbol preamble (25.0 μs assuming QPSK), and the turnoff time is 4 μs. These parameters require a 20-bit guard time and a 64-bit preamble at each end of the physical layer PDU. In this system, a 2ms uplink frame corresponds to 640 bytes. Assuming that the frame consists of both STR and ATR, and the length of each base slot in the STR is 27 bytes, a frame with one STR slot may also have, for example, 10 reserved minislots. It can have (each base slot has been converted to 5 reserved minislots), 2 data conflict slots, and 5 reserved data slots for ATM PDUs or VL PDUs.
【0070】
A downlink broadcast / multicast message can be used as a paging request message, as shown in Figure 11. The paging request and its associated response message are provided to allow a PC on the wired network to call another PC on the wireless network. The paging request message is useful for letting the wireless modem know that the wired host or another wireless modem wants to communicate. A wireless modem whose ID is included in the received paging request message responds with a paging response message, in addition to the connection request when there is currently no connection between the wireless modem and the access point. The paging feature requires a local server. The local server can be co-located with the PPP server if desired. This method is commonly used when a PC accessed over a wireless network does not have an IP address that can be accessed more efficiently.
【0071】
As shown in FIG. 11, a paging reservation message is defined to allow the PC2 1102 to invoke a call to the PC1 1104 attached to the wireless modem 1106. The PC (PC2) 1102 that is about to boot sends Call_Initiate message 1110 to the location / PPP server 1112 that defines its home registration server 1116. The home registration server 1116 then identifies the correct WH / IWF and relays Call_Initiate message 1118 to AP1120. The AP 1120 then sends a paging request 1130 to the wireless modem 1106 with which the PC1 1104 is associated. Finally, the wireless modem 1106 relays Call_Initiate message 1132 to PC1 1104.
【0072】
To accept the call, PC1 1104 sends a Call_Accept message 1140 to the wireless modem 1106 and at the same time attaches a Connect_Request message to it. The wireless modem 1106 then sends a paging response 1142 to AP 1120, which relays the message 1144 to WH / IWF 1116. The wireless modem 1106 also relays its Connect_Request message to AP 1120, which in turn relays it to WH / IWF 1116. WH / IWF 1116 sends Connect_Reply message 1145 to PC1 1104 and then relays Call_Accept message 1146 back to location server 1112. Finally, location server 1112 relays Call_Accept message 1148 to PC2 1102.
【0073】
The ODMAFQ method can provide preferred access within the same message stream from each user. Preferred access generally provides important control messages that have a higher priority than data messages. Some important control messages that can be sent by the wireless modem in the reserved slot are (a) an association request to request an association between the wireless modem and the access point, and (b) a connection request. Connect requests to request setup (c), paging responses to respond to paging requests, and (d) bandwidth requests to request bandwidth allocation after being silent for a while, etc. is there. Also, various possible messages can be assigned different priorities correspondingly because of different quality of service. In general, association requests, connect requests, and paging response messages are expected to have higher priority than data messages. As an example, if the service provider does not allow the user any more, the bandwidth request message will be given a lower priority than the connect request and paging response message so that the connection can be set up faster. Should be. Of the data messages, for example, voice signals carried over RTP / UDP packets are generally given higher priority than tcp / ip data packets.
【0074】
Fragmentation / reassembly mechanisms have been defined to allow fragment retransmission. APs and wireless modems generally have a MAC layer service data unit (SDU) that exceeds the maximum payload size or the remaining space available in the downlink or uplink frames. Fragment the service data unit (SDU) of. Alternatively, you can define a fragmentation threshold and a fragmentation threshold at which the MAC / SDU is fragmented. Each fragment has a sequence control field. All fragments belonging to the same SDU carry the same 12-bit sequence number, but are given different fragment numbers. It then indicates that the "More Fragment" bit in the frame control field is set for all but the last fragment, followed by the fragment. The fragments are then transmitted in order from the lowest fragment number to the highest fragment number.
【0075】
To meet in-sequence delivery requests, APs and wireless modems ensure that all fragments of the same SDU are sent before a new SDU is sent. Only missing fragments will be retransmitted. To avoid endless transmission delays (with concurrent transmission delays), a particular source (wireless modem or AP) maintains the MAC's SDU transmission timer, which passes the MAC's SDU to the MAC layer. It starts in a moment. When the timer exceeds the preset SDU lifetime of the MAC, all remaining fragments are discarded by the source and no attempt is made to complete the transmission of the SDU of that MAC.
【0076】
To prevent endless waiting for a permanently lost fragment, the receiving station reconstructs the MAC's SDU by combining the fragments in the order of the fragment numbers in the sequence control field. If the destination station receives a fragment with the "more fragment" bit set, it knows that it has not yet received the full MAC SDU. As soon as the receiving station receives a fragment with the "more fragment" bit cleared, it reassembles the SDU for that MAC and passes it to the higher layers.
【0077】
The receiving station (such as a wireless modem or AP) maintains a timer for the MAC's SDU, which is activated when the first segment of the MAC's SDU is received. The receiving station preferably has at least three timers to receive the SDUs of the three MACs at the same time. The destination station then discards all received fragments of the MAC's SDU for which the receive timer is not maintained. When the MAC SDU receive timer exceeds the preset receive MAC SDU lifetime, all fragments are discarded. If an additional fragment is received after the SDU timer of the receiving MAC has expired, the fragment is acknowledged and then discarded. Also, the receiving station discards any duplicate received fragments, but sends an acknowledgement in response.
【0078】
Manipulating the MAC protocol in multiple access schemes involves the following steps: They establish the transmit power level of the uplink, initial conflict of the uplink, resolve the conflict of the uplink, allocate the bandwidth of the uplink, allocate the downlink bandwidth of the AP, via the downlink control field. Notification of the status of the conflict and scheduling of uplink transmission via transmission permission. Especially in the case of constant rate traffic, each modem informs the AP of the arrival rate of the packet when setting up the connection so that only one access request is required for the entire duration of the connection.
【0079】
ODMAFQ The entire operation of the MAC protocol is shown in the flowcharts in Figures 13A and B. In the case of Figure 13A as seen from the remote host, after setting the power level for uplink transmission in 1310, the remote host participates in the initial uplink conflict in 1315 and has packets to send in the meantime. Each remote that is present sends an access request to the AP. If some of these access requests are determined to be in conflict in the 1320, they will be submitted into the same minislot and the conflicting remote host will participate in the uplink conflict resolution in the 1325. If not, the AP proceeds to allocate uplink bandwidth in the remote requesting access at 1330, and then allocates bandwidth for its own downlink transmission at 1335. .. Each remote host waits until it receives a transmit permission at 1337 during subsequent downlink transmissions, and when it receives one, it sends a waiting packet from its queue. At that time, if it is determined in 1338 that the remote queue is not empty, the remote returns in 1337 to wait for further send permission, otherwise it waits in 1339 for a new packet to arrive.
【0080】
As shown in Figure 13B, the AP monitors the activity in the received conflict reservation slots in the 1360. When it determines in 1365 that a successful access request has been received, the AP sends an acknowledgment (ACK) of the reservation in 1370 and adds the newly added remote to the scheduled list 1375. Regardless of whether there was a new successful access request in 1365, the AP monitors the uplink data slot in 1380 and determines in 1385 that it has received a successfully transmitted packet, unless the scheduled list is empty. Then the AP responds with a data ACK at 1390. The AP then schedules its own downlink packet in 1340, schedules the uplink transmission of a successfully competing remote host in 1345, issues the associated transmit permission in 1350, and then , Sends a downlink data packet at 1355 and then returns to 1360 to monitor activity in competing reserved slots.
【0081】
It may be desirable to allow an optional channel retention feature, which allows the access point to leave each queue empty for a short period of time without releasing bandwidth reservations. is there. This ensures that the high priority user stays in the list of reserved bandwidths for that base station for a certain amount of time allotted, after which it is released and channel reserved. By avoiding all the setup signaling and messaging required for this, short-latency real-time packets (ie, with little or no delay for packets of time-sensitive data, such as voice communications). To subsidize. This feature is used to trigger a timer in the wireless modem when the queue is empty. The wireless modem does not need to make a new access request as long as a new packet arrives at the wireless modem before the timer expires. On the AP, if this feature was turned on, the AP would replace the uplink even if the last uplink data transmission from its wireless modem indicated that the queue was empty. For each frame, also assign transmission permissions for one data slot for this particular wireless modem. The AP also starts the timer. When the timer expires and the AP is not receiving new packets from the wireless modem, the AP removes the wireless modem from its reserved bandwidth list. This channel retention feature is especially useful if the bandwidth reservation process takes some time to complete. This allows the low potential of real-time packets not far enough to guarantee different bandwidth reservation requests due to competition for each data packet, rather than arriving one after another in quick succession. However, for bursty sources that do not require this channel retention feature, the modem will compete minislot when it finds that a packet arrives and the buffer is empty.
【0082】
As shown in Figure 17, the power level of the uplink for data transmission between the base station and some remote hosts in a wireless network that employs ODMAFQ is determined by that remote host. Can be established during the initial access request message. The method used is very similar to the method used for the international standard IS95 "Channel Power Control" for Code Division Multiple Access (CDMA). If it is determined in 1710 that the transmit power level of the uplink between a particular remote host and the AP was previously remembered, then that remembered level is used in 1715 to transmit the uplink data. Be struck. Otherwise, the remote host first sends a short connection request message at the initial power level set in relation to the rated open rate power level in 1720. If the remote host's first transmission was unsuccessful, and therefore no acknowledgment was received from the AP at 1370, its power level is a pre-determined power increment at 1740. Is incremented by the amount of. Then, the transmission and increment steps are repeated until the transmission is successful. The power level at the time of the final successful transmission is stored in 1735 and used in 1715 for further data transmission between its remote host and the base station.
【0083】
In this preferred embodiment, the initial contention of the uplink utilizes the following method. If M minislots are available for contention in the next uplink frame, the initial (first time) contention message is sent according to:
【0084】
Random numbers x in the range 1.1 ~ M are generated from a uniform distribution on the modem of the remote node, 2. The initial conflict message is sent in the xth minislot in the next uplink frame.
【0085】
Carrier sensing can also be used during the initial competition, if desired. The channel is sensed before transmission. If access priorities are implemented, instead of choosing a random number in the range 1-M, the wireless modem will have 1-I.<sub>i</sub>Select the range of. Here I<sub>i</sub>Is the threshold for class i users, the lower the value, the higher the priority. That is, I<sub>i + 1</sub><I<sub>i</sub>Is shown. However, if the conflicting message is a conflicting data slot message rather than a conflicting reserved minislot request message, the message is sent in the next conflicting data slot.
【0086】
Can provide 3 or more access priority classes. As explained earlier, the uplink frame is N<sub>1</sub>Includes mini slots. For example, if there is a class with an access priority of P, each class with an access priority of i (where the smaller the number, the higher the priority) is 1 to I.<sub>i</sub>Conflicts can be sent within a minislot in the range of. Here I<sub>1</sub>= N<sub>1</sub>, I<sub>i + 1</sub> I<sub>i</sub>Is. Implement strict usage priorities at the top of this access priority scheme, and when an AP receives a conflicting request with a high usage priority, send a detach request frame to the wireless modem that supports the conflict. Allows you to disconnect existing connections with low usage priority.
【0087】
Collisions occur in competing slots when two or more wireless modems transmit in the same minislot. Also, if interference causes alteration of the data in a competing slot, the status of that slot is declared to be "COLLISION". As explained earlier, there are two types of competing slots in the uplink frame. They are (1) reserved slots containing minislots for bandwidth request messages, and (2) data slots containing short uplink bursty messages within competing superslots. At that AP, the RF energy in one uplink competing time slot is evaluated. If no energy was present, the competing slot is declared "IDLE". The status of a conflicting slot is declared "SUCCESS" if all of the following conditions are met: 1) RF energy was detected in that slot. 2) The preamble is not disturbed in that slot. 3) The frame check sequence (FCS) in that slot shows no error. The status of a competing slot is declared "COLLISION" if RF energy is detected in that slot and at least one of the following conditions is met: 1) The preamble in the slot is disturbed, or 2) the frame check sequence (FCS) in the slot indicates an error.
【0088】
FIG. 18A shows an embodiment of a method for access control according to one aspect of the invention. N competing reserved minislots are configured within each uplink frame 1810. The N mini-slots are organized into multiple access priority classes, each with a different priority. In 1815, the AP is configured to allow N access priority classes. In 1820, each remote host of access priority class i randomly picks up one conflicting minislot and sends an access request. Competing mini slots picked up are 1 ~ N<sub>1</sub>Is within the range of. Here N<sub>(i + 1)</sub><N<sub>i</sub>And N<sub>1</sub>= N. At 1825, the base station receives the access request and sequentially examines the received competing minislots. If in 1830 it is determined that the minislot currently being examined contains a non-conflicting request, the AP will access the remote host corresponding to the non-conflicting access request in 1835. To give permission. If the minislot currently being examined is determined in 1830 to contain a conflicting request, the AP does not send an ACK, which causes the affected remote node to perform conflict resolution in 1840. Let me do it. After the conflict resolution period, the AP grants access to the "winning" remote host in 1845. In other words, if it is determined that there are still other minislots to be examined in 1850, the AP will continue to check for minislot collisions in 1830 and access the host successfully requesting in 1835. Either allow or wait for the outcome of the conflict resolution in 1840.
【0089】
FIG. 18B is a flowchart showing an alternative embodiment of the method for access control according to one aspect of the invention. It is organized into multiple access priority classes, each with a different priority. In 1810, N competing reserved minislots are configured in each uplink frame. The N mini-slots are organized into multiple access priority classes, each with a different priority. In 1815 the AP is configured to allow N access priority classes. Then, in 1860, each remote host with access priority class i and stack level equal to 0 has a probability P.<sub>i</sub>Send an access request with. Here P<sub>(i + 1)</sub><P<sub>i</sub>, And P<sub>1</sub>= 1. At 1825, the base station receives the access request and sequentially examines the received competing minislots. If the minislot currently being examined in 1830 is determined to contain a non-conflicting request, the AP grants access in 1835 to the remote host corresponding to the non-conflicting access request. To do. If the minislot currently being examined in 1830 is determined to contain a conflicting request, the AP does not send an ACK, which causes the affected remote node to resolve the conflict in 1840. Let me do it. After the conflict resolution period, the AP grants access to the "winning" remote host in 1845. In 1850, if there were still other minislots to be examined, the AP would return to 1830 to continue checking for minislot collisions and grant access to the host successfully requesting in 1835. Alternatively, wait for the result of collision resolution in 1840.
【0090】
IDLE, SUCCESS and COLLISION status information is transmitted back to the wireless modem. The AP puts the status information for that slot in the downlink reservation knowledge field. There are three suitable conflict resolution methods that can be used. The first method is proposed in IEEE Standard 802.11 and is described below along with two new methods. Simulation results show that the second method described provides better access delay.
【0091】
In the first conflict resolution method proposed in the IEEE standard 802.11, the radio node that wants to transmit picks up one of the reserved minislots at random. If a collision is indicated, the modem affected by the collision will retransmit based on a random binary exponential backoff method. This backoff method operates as follows.
【0092】
1. Modem is 0 ~ 2<sup>j</sup>Generates a random number I that is uniformly distributed in the range of -1. Where j is the number of collisions the modem has experienced with respect to the packet it is trying to send. If j is greater than 10, I is 0 ~ 2<sup>10</sup>Selected from a uniform distribution in the range of -1. 2. The modem skips the same type of I-1 conflict slot opportunity (either a minislot or a data conflict slot), and the previously collided packet at the next immediately following conflict slot opportunity. Resend.
【0093】
The operation of this method is shown in Figure 14A. At 1402, the radio node waiting to access the AP randomly picks up one reserved minislot that sends an access request. If in 1404 it is determined that the node is affected by a collision, the node will generate a random number I in 1408 and skip the opportunity for the next I-1 competing slot of the same type in 1410. The node then resends an access request for the conflicting packet at 1412 at the immediate next conflict slot opportunity. If it is determined in 1404 that the node is unaffected by the collision, and if the queue at that node is empty in 1405, then the node sends the packet in 1406 and returns to standby state 1402. If in 1405 it is determined that the queue for that node is not empty, after receiving permission to send from the AP, the node will piggyback the current packet in 1407 for sending the next packet in that queue. It sends with the reservation request, and after receiving the send permission, continues to send the packet with the reservation request that was piggybacked in 1407 until the queue is determined to be empty in 1405, and the queue becomes empty. The last packet is then sent at 1406, after which the node returns to standby 1402.
【0094】
In the second and third methods, the AP broadcasts the result of each conflict in the reserved minislot to all radio nodes via a downlink broadcast message. In the second method, the modem in each radio node is characterized by a stack level, and only radio nodes with a stack level equal to 0 are allowed to send access request packets. Modems with a stack level value greater than 0 are considered to be in arrears. For example, if there are M reserved minislots, each remote node with a stack level of 0 can randomly pick up one of the M minislots. At the end of one time slot, radio node i changes the stack level based on the result of transmissions in that time slot. This method allows a newly active radio node to join an existing radio node with a stack level of 0 during a particular conflict resolution period. Each radio node in the request state increments its stack level by 1 if it does not send an access request packet and receives the specified acknowledgement from the base station (AP) (for example, in a collision). To do. On the other hand, if the radio node receives a positive acknowledge from the base station indicating that it has successfully sent an access request, the radio node decrements its stack level. Each radio node participating in an access request transmission will randomly "like a lottery" to determine whether its stack level remains at level 0 or is incremented upon receipt of the specified recognition from the base station. Do things (flips a coin) ".
【0095】
The rules for the second method are as follows. 1. When a wireless node first wants to gain access to the network, or when it has access and wants to send new data, the node is put into a request state and assigned a stack level of 0. 2. When there are M reserved minislots, each radio node in the request state randomly assigns one of the M reserved minislots to its own assigned minislot to send access request packets. Pick up. 3. If the radio node is characterized by a stack level equal to 0, it sends an access request packet. However, when the remote node is characterized by a non-zero stack level, it does not send access request packets. 4. At the end of that time slot, each radio node is the result of an access request reported to its assigned minislot in the reserved acknowledgement field of the downlink message from the access point. Change your stack level based on (either collision, idle, or success).
【0096】
A. The radio node that sends the access request and receives the "success" result is removed from the request state. B. A radio node that sends an access request and receives the result of a "collision" will randomly draw to either increment their stack level by 1 or leave their stack level at 0. Execute based on the result of. C. A radio node that is in a request state and did not send an access request (ie, a node that has a delinquency at stack level> 0) reports in the reserved collision field for its assigned minislot. If the result is a "collision", increment your stack level by 1. D. Radio nodes in the request state that did not send an access request (ie, nodes in arrears at stack level> 0) report in the Reserved Acknowledgment field for their assigned minislot. If the result being "successful" is, decrement your stack level by 1.
【0097】
The operation of this method is shown in Figure 14B. A radio node waiting to access an AP or send new data sets its stack level to 0 at 1432 and enters a request state. If the node's stack level is determined to be 0 in 1434, the node randomly picks up one reserved minislot in 1436 to send an access request. If the result of the request is determined to be "successful" at 1438, and the queue at that node is determined to be empty at 1439, then the node sends the current packet at 1440 and exits the request state. And returns to 1432 from the standby state. If in 1439 it is determined that the node is not empty, after receiving permission to send from the AP, the node is piggybacked at 1441 for the current packet to send the next packet in its queue. When sending with a reservation request and receiving permission to send until the queue is determined to be empty in 1439, the piggybacked reservation request continues to be sent in 1441 and the queue is empty. It sends the remaining packets at 1440, exits the request state and returns to the wait state 1402.
【0098】
If the result of the booking request is determined to be unsuccessful in 1436, the node will participate in a random draw in 1444 and either increment its stack level in 1448 or reduce its stack level to 0 in 1446. Decide if you want to leave it. If the stack level remains 0 at 1446, the node again randomly picks up one reserved minislot for sending an access request at 1436 and sends that access request. If the stack level is incremented at 1448, the stack level will be non-zero at 1434. If the stack level of any remote node is determined to be non-zero in 1434, and if the result of a previous reservation request in 1450 was a "collision", then that node has only 1 stack level in 1452. Increment. If it is determined in 1450 that the result of the previous reservation request was not a "collision", the node decrements its stack level by 1 in 1454.
【0099】
The third conflict resolution method is a modified version of the second method. In the third collision resolution method, the modem at each radio node is again characterized by the stack level, and only the radio node with a stack level of 0 is allowed to send access request packets. Modems with a stack level greater than 0 are considered to have delinquency. The rules of the third method are as follows.
【0100】
1. When a wireless node first wants to gain access to the network, or when it has access and wants to send new data, the node is put into a request state and assigned a stack level of 0. 2. When there are M reserved minislots, each radio node in the request state randomly assigns one of the M reserved minislots to its own assigned minislot to send access request packets. Pick up. 3. If the radio node is characterized by a stack level equal to 0, it sends an access request packet. However, when the remote node is characterized by a non-zero stack level, it does not send access request packets. 4. At the end of that time slot, each radio node is the result of an access request reported to its assigned minislot in the reserved acknowledgement field of the downlink message from the access point. Change your stack level based on (either "Collision", "Idle", or "Success").
【0101】
A. The radio node that sends the access request and receives the "success" result is removed from the request state. B. A radio node that sends an access request and receives the result of a "collision" will randomly draw to either increment their stack level by 1 or leave their stack level at 0. Execute based on the result of. C. Radio nodes that are in the request state and did not send an access request (ie, nodes that have a delinquency at stack level> 0) are at least 80% (or some other pre-determined) of the Reserved Acknowledgment field. If the threshold) is reported to be either "successful" or "idle", decrement your stack level by 1. If not, the remote level increments its stack level by 1. D. When the stack level of a modem with delinquency is decremented to 0, the modem has M minislots (or I if wireless priority is practiced).<sub>i</sub>Randomly pick one of the minislots) and resend the request.
【0102】
The behavior of this method is shown in Figure 14C, which is similar to the figure in Figure 14B. At 1432, a radio node waiting to access the AP or send new data sets its stack level to 0 and enters a request state. If the stack level of the node is determined to be 0 in 1434, then in 1436 the node randomly picks up one reserved minislot to send the access request and sends the access request. If the result of the request is determined to be "successful" in 1438, and the queue at that node is determined to be empty in 1439, then the node sends the current packet in 1440, and from the request state. Escape and return to standby state 1432. If 1439 determines that the queue on that node is not empty, after receiving permission to send from the AP, the node will piggyback the current packet at 1441 for the next packet in that queue. After receiving the transmission permission, it continues to transmit the packet together with the reservation request that was piggybacked at 1441. It continues until the queue is determined to be empty in 1439, and when the queue is empty it sends the remaining packets in 1440, then exits the request state and returns to the wait state 1402.
【0103】
If the result of a reservation request in 1436 is determined not to be "successful" in 1438, the node will participate in a random draw in 1444 and either increment its stack level by 1 in 1484 or it will be itself in 1446. Know if you want to keep the stack level of 0. If the stack level remains 0 in 1446, the node randomly picks up one reserved minislot again in 1436 to send the access request and sends the access request. If the stack level is incremented in 1848, the stack level will be determined to be non-zero in 1434. If the stack level of any remote node is determined to be non-zero in 1434, then in 1460 the results of all reservation requests during the previous cycle are greater than a certain "threshold" percentage, or Or if it is determined in 1460 to be "colliding" because it is equal, the node increments its stack level by 1 in 1462. If the result of a previous reservation request is determined to be "non-conflicting" in 1460, the node decrements its stack level by 1 in 1464.
【0104】
Note that due to the hidden terminal problem, all transmitted frames need to be acknowledged. Acknowledgment messages must not be sent in conflict mode. Therefore, transmission schedules and transmission permissions are used as a mechanism for acknowledging downlink MAC unicast frames. When a wireless modem receives a downlink broadcast frame, it first interprets the transmit schedule and transmit permissions. If the wireless modem was not the turn to transmit data, and if the wireless modem was a receiver of unicast frames (ie, the wireless modem's ID was in its transmission schedule). The wireless modem schedules an acknowledgment message for the unicast frame in the uplink frame immediately following it. All knowledge messages are sent first, and then any data messages are allowed by the send permission. For wireless modems that receive both transmit permission and unicast messages in a downlink frame, allow these modems to piggyback their knowledge at the end of each uplink data transmission. , Different transmission permissions are issued. To acknowledge the uplink unicast frame, the AP either schedules the unicast knowledge message or piggybacks the knowledge message over the downlink data transmission.
【0105】
As mentioned earlier, the number of reserved minislots available can be changed dynamically. For example, if there are k mini-slots in a competing reserved slot, there are a total of N slots, and N1 of them is a reserved slot that contains a total of N1 * k mini-slots, then the remaining (N-N1) slots are data slots. If NUM_RA_MIN and NUM_RA_MAX are the minimum and maximum number of reserved minislots required for the system, respectively, the number of reserved minislots available is based on the percentage of the total queue length of idle minislots and uplinks. May change dynamically.
【0106】
Four methods have been developed to dynamically adjust the total number of reserved minislots available to remote nodes to make access requests. In each of these methods, the total uplink queue length at any time is "q", the percentage of minislots that are idle at any time is "idle", and one at any time. The number of mini-slots in a frame is "no_mini", and the number of non-conflicting data slots in a frame at any time is "no_slots". The base station (AP) adjusts how quickly the number of available minislots can be changed. With each iteration of the decision process, the base station broadcasts the number of reserved minislots available to the remote node. The base station's determination is based on the results of one of these methods. For each method, the remote node piggybacks uplink queue length information to the base station during the data transmission of each uplink.
【0107】
A software implementation of Method 1 for dynamically adjusting the number of reserved minislots is given below, and is shown graphically in the flowchart of Figure 12A. If ((q> HIGH_THRESH) && (idle> IDLE_THRESH) H1)) { If (State! = 1) { no_mini = no_mini-k; no_slots = no_slots + 1; State = 1 } } If ((q <LOW_THRESHOLD) && (idle <IDLE_THR) ESH2)) { If (State == 1) { no_mini = no_mini + k; no_slots = no_slots-1; State = 0 } } [0108]
As shown in Figure 12A, if the total length of the uplink queues at 1201 is greater than the higher threshold (HIGH), then at 1202 the percentage of idle minislots (IDLE) is first. If it is determined that it is not greater than the idle threshold (IDLE1) of, the number of minislots (N) remains unchanged. However, if 1202 determines that the percentage of idle minislots is greater than the first idle threshold, and 1203 determines that the state is "1" (the number of minislots is reduced). The number of minislots in the frame was decremented by a certain value k at 1204, the number of data slots in the frame (SLOTS) was increased by 1 and that state. Is set to "1". If it is determined in 1201 that the total uplink queue length is not greater than the higher threshold, and in 1205 the sum of the uplink queue lengths is greater than the lower threshold (LOW). If determined to be small, and if in 1206 the percentage of idle minislots is determined not to be less than the second idle threshold (IDLE2), the number of minislots remains unchanged. However, in 1206 the percentage of idle minislots was determined to be less than the second idle threshold, and in 1207 the state was "1" (meaning that the number of minislots had just been reduced). If determined, the number of minislots in the frame is incremented by k at 1204, the number of data slots is decremented by 1, and the state is set to "0". In all four methods, the threshold and the value of k can be pre-specified as needed.
【0109】
A software implementation of Method 2 for dynamically adjusting the number of reserved minislots is given below and is shown graphically in the flowchart of Figure 12B. In the methods of FIGS. 12B and 12D, HIGH2> HIGH1 and LOW2> LOW1. If ((q> HIGH2) && (idle> IDLE_THRSH1)) { If (State == 0) { no_mini = no_mini-2k; no_slots = no_slots + 2; State = 2 } else if (State == 1)} no_mini = no_mini-k; no_slots = no_slots + 1; State = 2 } } else if ((q> HIGH1) && (idle> IDLE_THRS) H1))} If (State == 0) { no_mini = no_mini-k; no_slots = no_slots + 1; State = 1 } } If ((q <LOW1) && (idle <IDLE_THRESH2)) { If (State> 0) { If (State = 1) { no_mini = no_mini + k; no_slots = no_slots + 1; State = 0; } else { no_mini = no_mini + 2k; no_slots = no_slots-2; State = 0; } } } else if ((q <LOW2) && (idle <IDLE_THRES) H2)) { If (State == 2) { no_mini = no_mini + k; no_slots = no_slots-1; State = 1 } } [0110]
As shown in Figure 12B, if the total uplink queue length is determined to be greater than the first higher threshold (HIGH2) at 1210, and the percentage of idle minislots is If it is determined in 1211 that it is not greater than the first idle threshold, the number of minislots remains unchanged. However, at 1211 the percentage of idle minislots is determined to be greater than the first idle threshold, and at 1212 the state is determined to be "0" (meaning that the number of minislots has just been increased). If so, at 1213 the number of minislots in the frame is reduced by 2k, the number of data slots in that slot is increased by 2, and the state is set to "2". If the state is determined to be "1" in 1214, the number of minislots in that frame is decremented by k in 1215, the number of data slots in that frame is incremented by 1, and the state is "2". Is set to.
【0111】
In the method of FIG. 12B, if the sum of uplink queue lengths is determined to be greater than the first higher threshold in 1210, then the sum of uplink queue lengths is second in 1210. If it is determined to be greater than the higher threshold (HIGH1) of, and if the percentage of idle minislots is determined to be no greater than the threshold of the first idle at 1217, then the number of minislots is It remains immutable. However, if at 1217 the percentage of idle minislots is determined to be greater than the first idle threshold, and at 1218 the state is determined to be "0", then the number of minislots in that frame is at 1219. It is decremented by k, the number of data slots in that frame is incremented by 1, and the state is set to "1".
【0112】
The sum of the uplink queue lengths was determined to be no greater than the first higher threshold at 1210 and no greater than the second higher threshold at 1220, but 1221 If it is determined in 1220 that it is not less than the first lower threshold "LOW1" and not less than the second lower threshold "LOW2", the number of minislots remains unchanged. .. However, the sum of the uplink queue lengths was determined to be no greater than the second higher threshold at 1220 and no lower than the first lower threshold at 1221. If it is determined in 1221 to be less than its lower threshold, the percentage of idle minislots is determined to be less than the second idle threshold in 1223, and the state is "2" in 1224 ( If it is determined (meaning that the number of minislots has just been reduced), the number of minislots in that frame is increased by k in 1225 and the number of data slots in that frame is only one. It is reduced and the state is set to "1".
【0113】
Idle if the sum of the uplink queue lengths is determined to be no greater than the second higher threshold at 1220 and less than the first lower threshold at 1221. If the percentage of minislots in 1226 is determined to be less than the second idle threshold, and the state is determined to be non- "0" in 1224, then the state is determined to be "1" in 1228. The number of minislots in a frame is increased by k in 1230, the number of data slots in that frame is decremented by 1, and the state is set to "0", but the state is "2". If so, the number of minislots in that frame is increased by 2k at 1229, the number of data slots in that frame is decremented by 2, and the state is set to "0".
【0114】
A software implementation of Method 3 for dynamically adjusting the number of reserved minislots is given below, and is also shown graphically in the flowchart of Figure 12C. If ((q> HIGH_THRESH) && (idle> IDLE_THRESH) H1)) { If (no_mini> NUM_MINI_MIN) { no_mini = no_mini-k; no_slots = no_slots + 1; } } If ((q <LOW_THRESHOLD) && (idle <IDLE_THR) ESH2)) { If (no_mini <NUM_MINI_MAX) { no_mini = no_mini + k; no_slots = no_slots-1; } } [0115]
As shown in Figure 12C, if the sum of uplink queue lengths is determined to be greater than the higher threshold at 1240, the percentage of idle minislots will be the first idle at 1241. If it is determined that it is not greater than the threshold, the number of minislots remains unchanged. However, if the percentage of idle minislots is determined to be greater than the first idle threshold in 1241, and if the number of minislots in 1242 is greater than the minimum number of allowed minislots (MIN). , The number of minislots in the frame is reduced by k at 1243, and the number of data slots in the frame is increased by 1. The sum of the uplink queue lengths is determined to be no greater than the higher threshold at 1240, the sum of the uplink queue lengths is determined to be less than the lower threshold at 1244, and If the percentage of idle minislots is determined to be no less than the second idle threshold at 1245, the number of minislots remains unchanged. However, the percentage of idle minislots was determined to be less than the second idle threshold at 1245, and the number of minislots was determined to be less than the maximum number of minislots allowed (MAX) in 1246. If so, the number of minislots in that frame is incremented by k at 1247, and the number of data slots in that frame is decremented by 1.
【0116】
A software implementation of Method 4 for dynamically adjusting the number of reserved minislots is given below, and is also shown graphically in the flowchart of Figure 12D. If ((q> HIGH2) && (idle> IDLE_THRESH1)) { If (no_mini> NUM_MINI_MIN) { no_mini = no_mini-2k; no_slots = no_slots + 2; } } else if ((q> HIGH1) && (idle> IDLE_THRE) SH1)) { If (no_mini> NUM_MINI_MIN) { no_mini = no_mini-k; no_slots = no_slots + 1; } } If ((q <LOW1) && (idle <IDLE_THRESH2)) { If (no_mini <NUM_MINI_MIN) { no_mini = no_mini + 2k; no_slots = no_slots-2; } } else if ((q <LOW2) && (idle <IDLE_THRES) H2)) { If (no_mini> NUM_MINI_MAX) { no_mini = no_mini + k; no_slots = no_slots-1; } } [0117]
As shown in Figure 12D, the sum of the uplink queue lengths is determined to be greater than the first higher threshold at 1250, and the idle minislot percentage is the first idle at 1251. If determined not to be greater than the threshold, the number of minislots remains unchanged. However, if the percentage of idle minislots is determined to be greater than the first idle threshold in 1251 and the number of minislots is determined to be greater than the minimum number of minislots allowed in 1252, then that The number of minislots in a frame is reduced by 2k at 1253, and the number of data slots in that frame is increased by 2. It is determined that the total uplink queue length is not greater than the first higher threshold at 1250, and the total uplink queue length is greater than the second higher threshold at 1254. If determined to be large, and the percentage of idle minislots is determined to be no greater than the first idle threshold at 1255, the number of minislots remains unchanged. However, if the percentage of idle minislots is determined to be greater than the first idle threshold at 1255 and the number of minislots is determined to be greater than the minimum number of minislots allowed at 1256, then that The number of minislots in a frame is decremented by k at 1257, and the number of data slots in that frame is incremented by 1.
【0118】
In the method of Figure 12D, the sum of the uplink queue lengths is determined to be no greater than the first higher threshold at 1250 and no greater than the second higher threshold at 1254. If determined, but not less than both the first lower threshold in 1258 and the second lower threshold in 1262, the number of minislots remains unchanged. However, the sum of the uplink queue lengths was determined not to be greater than the second higher threshold in 1254 and less than the first threshold in 1258, but was determined to be no less than the first threshold in 1262. Determined not less than the lower threshold of 2, the percentage of idle minislots is determined to be less than the second idle threshold in 1263, and the maximum number of minislots allowed in 1264. If it is determined to be less than the number of, the number of minislots in the frame is incremented by k in 1265 and the number of data slots in the frame is decremented by 1.
【0119】
Idle if the sum of uplink queue lengths is determined to be no greater than the second higher threshold in 1254 and less than the first lower threshold in 1258. If the percentage of minislots in 1259 is determined to be less than the threshold for the second idle, and the number of minislots is determined to be less than the maximum number allowed in 1260, then the minislots in that frame The number of is increased by 2k in 1261, and the number of data slots in that frame is decreased by 2.
【0120】
The role of APs in responding to uplink bandwidth requests from modems is high bandwidth efficiency of outstanding service, whether they arrive in pure reserved minislots or in the form of piggybacks. Controlling the transmission of uplinks to achieve a balance with quality of service (QoS) management. The conditions of QoS for constant bit rate CBR traffic are extremely important and strict, but they are relatively free for traditional data traffic. Therefore, one goal of bandwidth allocation schemes in APs is to take advantage of these diverse QoS requirements to achieve a high degree of statistical multiplexing. APs require a downlink scheduling system to determine how they should send downlink traffic from various connections. Similarly, in order to coordinate uplink transmissions from the associated wireless modem, the AP requires a system for scheduling uplink transmission opportunities for each wireless modem. The scheduling system may be as simple as a round robin, strict priority or first come first serve algorithm, or more complex as a fair queuing algorithm. You can also. As explained earlier, many schedulers have been proposed that are all variants of fair queuing.
【0121】
The uplink scheduling system does not necessarily have to be the same as the downlink scheduling system, but for simple embodiments, the same can be selected. Obviously, scheduling systems are desired to provide quality of service to end users. Different classes of service can be defined to meet the diverse QoS needs of different applications, as in the case of ATM networks. Possible classes of service are constant bit rate (CBR), real-time and non-real-time variable bit rate (RT VBR, NRT VBR), unspecified bit rate (UBR), and available bit rate (ABR). and so on. To meet the QoS requirements of different classes of service, there must be a method that does not require static prioritization for allocating bandwidth and buffer resources.
【0122】
Fully see all outbound queues (ie, outbound queues for both wired and wireless hosts) for the AP to perform downlink and uplink scheduling when the wireless modems are geographically dispersed A mechanism is needed for the wireless modem to pass relevant information to the base station, which is the only location where it can. There are at least two ways to calculate the service tag for all hosts associated with the access point. In these methods, the wired host with which the associated wireless modem is communicating is assumed to be permanently associated with that access point. In one method, the base station can broadcast the virtual time and class of service assigned share of the system to each wireless modem. Each wireless modem then calculates its own service tag and informs the base station about it via access request packets or piggybacking in data transmission. Instead, the wireless modem can simply inform the base station of the size of its queue (again via an access request packet or by piggybacking in data transmission), and the base station can do more than just to a wired host. The service tag for each base station can be calculated. The second method is more efficient in terms of downlink bandwidth utilization. This is because the base station does not need to send its assigned service share (which can change dynamically) to each wireless modem.
【0123】
An embodiment of the first method is shown in FIG. 15A. The base station broadcasts the system's virtual time to remote hosts at 1510. Each remote host calculates the value of the service tag for each of the newly arrived packets at 1515 and then sends the value of the first tag of them to the base station at 1520. Transmission permissions are assigned at the base station based on the value of the service tag received from that remote host in 1530 and the available data slots. The transmit permission is broadcast to the remote host at 1540, and then the packets are received remotely at 1540 in the order specified by the transmit permission. If the packet is lost or received in error on the 1545, the remote sending it either through notification by the AP or by failing to receive an ACK from the AP's response. , Be aware of this issue. The sending remote then recalculates the values of all the service tags in its queue at 1550, including packets that failed to send. This procedure continues until it is determined in 1555 that all scheduled packets have been inspected, after which the system broadcasts the current virtual time again in 1510.
【0124】
An embodiment of the second method is shown in FIG. 15B. A packet count is sent from each remote host to the base station at 1560, and each packet count is either a fixed-size packet number or the length of a variable-length packet that should be sent from the remote host to the base station. Represents. The base station calculates the value of the service tag for each remote host in 1565, and in 1530 the remote host also assigns transmit permissions based on the service tag and available data slots, and in 1535 the transmit permit is assigned. Broadcast to a remote. Packets are received remotely at 1540 in the order they were sent by their permission to send. If the 1545 determines that a packet has been lost or received in error, the AP recalculates the value of the service tag for that remote host on the 1570. This procedure continues until it is determined in 1555 that all scheduled packets have been examined, after which the remote host sends its respective packet count to the base station in 1560.
【0125】
Figure 15 In the methods A and B, if the transmitted packets were lost, the base station (access point) or wireless modem would put all the packets in the queue based on the virtual time of the current system. Recalculate the value of the new service tag for it. In an alternative embodiment, the AP or radio node maintains a packet queue and line head tag. In this method, if the packet is lost, only the tag on the head of the line needs to be changed. If the line head packet is sent successfully, the remaining queued packets will automatically receive the correct tag (recalculated line head tag + appropriate increment). This alternative embodiment has the advantage that the number of CPUs used is small. Retransmissions in polling systems are generally R. Kautz's "Distributed Self-Clocking Fair Queuing Architecture for Wireless ATM Networks" 1997 International Symposium on Personal Indoor and Mobile Radio It is explained in Communications (Symposium on Personal Indoor and Mobile Wireless Communications). However, Kautz does not describe the technique of the present invention for recalculating the value of a tag when a packet is lost.
【0126】
It is clear that the method for recalculating the service tag after packet loss is very important in wireless systems where such loss is common. For half-duplex schemes, are both uplink and downlink queues on the access point as if they share the same bandwidth, that is, if the system has only one virtual time? It is managed like. For full-duplex schemes, separate system virtual times can be used for uplink and downlink traffic. It is also desirable that the remote host be divided into one or more separate groups for downlink transmission, with each group receiving different priorities and different system virtual times. When the modem receives an acknowledgment for its initial access request, it waits until it receives permission to send from the AP. Each time the modem sends a packet, it indicates whether the packet remains in its buffer. This piggybacking serves as a contention-free bandwidth reservation for the modem.
【0127】
The service tag calculation is shown in Figure 16. First of all, the AP calculates the service tag increment in 1610 based on the service share assigned by each node. Each node packet is then assigned a service tag according to the fair queuing algorithm applicable in 1612. The packet is then served in 1614 according to the order of its assigned service tags. In 1516, if a packet arrives from a node that was previously emptied, the packet on that newly transmitting node starts with the tag of the packet currently in service at 1618 + the service tag increment for that node. And the service tag is assigned. If it is determined in 1620 that an error has occurred in sending a packet, the service tag for that packet is reassigned at 1622 to the current tag + the increment of the service tag for that node. The remaining packets for that node then receive a new service tag at 1622, which is the previous service tag plus the increment of that node's service tag. This can be done either by a direct recalculation of all service tags for that node, or by a recalculation of the line head tags if they exist. For a line head tag, if the line head packet is successfully transmitted, the remaining packets for that node in the queue will automatically receive the next correct tag. Note that the service tags of all other nodes remain unaffected by the retransmission of packets to this node. This means that the QoS experienced by other nodes is unaffected.
【0128】
In this preferred embodiment of one aspect of the invention, the order in which transmit permissions are sent to all wireless modems associated with an access point is based on the self-clocking fair queuing algorithm described above. .. The order in which access points serve various downlink connections is also based on a self-clocking fair queuing algorithm. For example, the system has a capacity of 16 units and 3 sessions, its session IDs are 1, 2, and 3, and its session sharing is r.<sub>1</sub>= 1, r<sub>2</sub>= 2, and r<sub>3</sub>Can be = 3 respectively. Assuming that the length of any session is always L = 8 for the sake of simplicity, each packet takes 0.5 time units to be sent. At that time, the service tag increment, that is, L / r<sub>i</sub>Are 8, 4, and 2 for sessions 1, 2, and 3, respectively. If session 1 contains 4 packets at time t, session 2 contains 8 packets, and session 3 is free of delinquency by t = 3, then the packet of session 1 is serviced according to equation (1). Receive tags 8, 16, 24, and 32. Similarly, session 2 packets receive service tags 4, 8, 12, 16, 20, 24, 28, and 32.
【0129】
Figure 9A shows the service tag of this example packet at time t = 0. Packets for session 1 with service tag 8 902, service tag 16 904, service tag 24 906, and service tag 32 908 are packets from session 2 912, 914, 916, 918, 920, 922, And 924 interleaved. Packet 910 from session 2 with service tag 4 is currently in service.
【0130】
Figure 9B shows the service tags of the remaining queued packets at time t = 3, just before the packets arrive from session 3. Packet 918 from session 2 with service tag 20 is currently in service. Figure 9C shows the service tags of the packets at time t = 3 immediately after the arrival of nine packets 930, 932, 934, 936, 938, 940, 942, 944 and 946 from session 3. Note that the service tag for the first packet 930 in session 3 starts at 22. This is because when the packet arrived, the packet that was being serviced at that time had a service tag of 20. Therefore, if the service tag increment is 2, the first packet 930 in session 3 will receive service tag 22. Therefore, the service tags from session 3 onwards are 24, 26, and 28.
【0131】
Figure 9D shows the service tags of the remaining queued packets at time t = 4.5. Sending packet 906 with service tag 24 from session 1 is in error. Therefore, the access point recalculates 32 new service tags for this packet 950 that needs to be sent. The access point also recalculates the service tags for the remaining packets from session 1. It affects only one other packet 952 (908 in Figure 9C) in this case, which receives 40 new service tags. Thus, the retransmission of one packet from a particular session does not affect the quality of service of the other sessions.
【0132】
When the remote host PC wants to receive data service, it sends a connection message to the wireless modem. Upon receiving this message, the wireless modem constantly monitors the broadcast frames being sent by the AP. Beacon messages are part of this broadcast frame and provide timing information, the network's ESS-ID, its AP's BSS-ID, information about competing slots, AP's load measure, and so on. Next, the wireless modem selects the AP it wants to associate with and sends a MAC layer association request frame. Conflicts can occur because association request frames are sent in conflict mode. If the wireless modem does not receive the association response frame from that AP, it must retransmit the association request frame. After the maximum number of attempts, the wireless modem sends a connection failure message to the remote host's PC, indicating that the wireless modem cannot be associated with the AP at this point.
【0133】
Upon receiving the association request frame from the wireless modem, the AP successfully authenticates the wireless modem and then sends an association response frame with a status code of "successful" to the modem. Authentication is done at the network layer. When the user requests a connection via the wireless modem, the connection request is forwarded by the access point to the wireless hub. The wireless hub then authenticates the user. If the user is successfully authenticated, a unique connection cookie is provided by the wireless hub to the access point. If it is desirable to provide different QoS for different connections from the same user, different connection cookies will be assigned to the same user. Similarly, if it is desirable to provide different QoS to different users (even if they can be from the same wireless modem), each user will be given a different connection identity.
【0134】
If the wireless modem is not successfully authenticated, an association response frame with the appropriate reason code is sent. Different reason codes can be defined to cover each possible different reason for the association failure. If you want to combine MAC layer registration with network layer registration, the request frame for that association is sufficient for the AP to be able to send network layer registration packets to the requesting wireless hub. Must include proper login information. In this case, the AP does not send its associated response frame until it receives further response from the wireless hub.
【0135】
If the MAC layer registration is not combined with the network layer registration, the AP can relay the MAC layer registration to the wireless hub before sending the associated response frame. Separation of MAC layer registration and network layer registration is useful when it is desirable that the network software be reusable for other physical implementations. Also, if different users are using the same wireless modem to make different connection requests, that wireless modem may be required to register for only one MAC layer, but multiple network layers. It may still be necessary to perform the registration of. If there is only one user per wireless modem, combining MAC layer registration with network layer registration can help reduce the number of airlink frames during the registration process.
【0136】
Upon receiving the reconnect message from the remote host's PC, the wireless modem reassociates with the access point via the following steps: 1. The wireless modem sends a frame of the reassociation request to the access point. 2. If the reassociation response frame is received with a "successful" status code, the wireless modem sends a successful reconnection message to the PC. 3. If the reassociation response frame is received with a status code other than "success", the wireless modem sends a reconnection failure message to the PC. The access point works as follows to support station reassociation.
【0137】
1. Whenever a reassociation request frame is received from one station and that station is authenticated, the access point sends a reassociation response with a status value that means "success". 2. If the status value is "success", the connection cookie assigned to that station is included in the response. 3. If the reassociation is successful, the access point updates its MAC filter table accordingly. The access point also informs the wireless hub about this reassociation. 4. If the reassociation request is unsuccessful, the access point sends a reassociation response to the wireless modem with the appropriate reason code.
【0138】
If for some reason either the PC or the access point wants to disconnect from the other party, a disconnect request frame is sent. The PC sends a disconnect message to the wireless modem and triggers the wireless modem to send a detach request frame to the access point. The access point responds with a detach response frame that indicates the success or failure of the detach operation initiated by the PC. The wireless modem relays this response back to the PC via a detached response message.
【0139】
Under some circumstances, such as when overloaded, or when a higher priority is given to another user, the access point associates with a particular wireless modem previously associated with that access point. It may need to be released. In that case, the access point sends a disassociation request message to the wireless modem. The wireless modem responds to the access point with a disassociation response frame and relays the disassociation message to all PCs attached to the wireless modem. The access point can also disconnect a particular connection via a disconnect request message that is relayed to the PC via a wireless modem. For wireless modems that support more than one PC, the disassociation request message is not used unless you want to disable the entire wireless modem.
【0140】
Based on the list of access points that the wireless modem can communicate with, the wireless modem determines which AP to associate with by selecting the AP that best meets the following criteria (the lower the number, the higher the priority): 1. The signal-to-noise ratio, RSSI and SNR are the best. 2. The least loaded (ie, the least number of equivalent associated users). 3. The power required to communicate is minimal.
【0141】
Uplink / downlink transmission time ratio can be adjusted dynamically. One way to implement this is to take advantage of the "more" bit or uplink queue size information that is piggybacked over the uplink data transmission. Upon receiving this information from all currently active remote nodes within that cell / sector, the access point will have complete information about the total uplink / downlink queue size, and this The information can be used to dynamically adjust the uplink / downlink ratio based on the total uplink / downlink queue size information. One simple way to do this is to use threshold-based techniques. When the total uplink / downlink queue size ratio drops below k1, the access point sets the uplink / downlink ratio to s1 and the uplink / downlink queue size ratio is k2 (k2). When increasing beyond> k1), the access point sets the uplink / downlink ratio to s2 (s2> s1). At this point, traffic characterization seems to indicate that a 4: 1 ratio is appropriate.
【0142】
As shown in FIG. 10, frame 1010 contains four reserved minislots 1012, two uplink slots 1020, three downlink slots 1030, and a beacon message 1040. Beacon message 1040 contains information that specifies the total number of slots and the number of downlink slots that will be present in the next frame 1050. Frame 1050 reflects this information and contains the same number of reserved minislots 1012 (4), but the number of uplink slots 1020 is 3 and the number of downlink slots 1030 is 2. Yes, it also includes a new beacon message 1060 that specifies the uplink / downlink transmission time ratio for the next frame, etc.
【0143】
For PC flow control, the wireless modem sets the higher and lower buffer occupancy thresholds for each direction (uplink / downlink) and monitors the buffer occupancy. To do. When the higher threshold of buffer occupancy for uplink traffic is reached, a flow control signal (Xoff) is sent from the wireless modem to the PC. When the buffer occupancy for uplink traffic falls below the lower threshold (after previously exceeding the higher threshold), the wireless modem sends a "Xon" signal to the PC. When the buffer occupies the higher threshold for downlink traffic is reached, the wireless modem turns on the Xon / Xoff bit in the frame control field when sending a message to the access point. Set to. If there are no uplink frames to send, a zero length message is sent. Such frames are considered high priority control frames.
【0144】
For frequency division multiplexing transmission versions, wireless modems and access points maintain memory for buffering both uplink and downlink messages. For the frequency division full-duplex transmission version, the AP maintains one buffer for both uplink and downlink messages. A typical buffer size is 100 kbytes for modems and APs for FDHD and 200 kbytes for APs for FDFD. Wireless modem buffers are typically k between downlink and uplink traffic.<sub>1</sub>It is partitioned into a ratio of 1.
【0145】
The access point buffer is also the ratio of downlink traffic to uplink traffic.<sub>2</sub>It is partitioned into 1. Again, the traffic characterization seems to suggest that 4: 1 (downlink capacity is four times larger than uplink capacity) is appropriate. When the downlink buffer occupancy threshold is reached, the access point sends an "Xoff" message to the wireless hub. When the downlink buffer occupancy reaches the lower threshold (after previously exceeding the higher threshold), it sends an "Xon" message to the wireless hub. When the uplink buffer occupancy reaches the higher threshold, the access point sends the next broadcast frame to all associated wireless modems with the "Xon" in its frame control field. Set the bit. When the uplink buffer occupancy reaches the lower threshold (after previously exceeding the higher threshold), the access point controls the frame when it sends the next broadcast frame. Clear the "Xoff" bit in the field. In addition, more advanced flow control schemes are used by the access point to track the buffer occupancy (in both directions) of each wireless modem, and the higher threshold of the uplink buffer. In the case of a violation, a Xon / Xoff MAC frame is sent to a specific wireless modem, or in the case of a higher threshold violation in the downlink buffer, the corresponding connection ID is notified to the wireless hub. To.
【0146】
One aspect of the invention is the ability to support permission control. When a PC user submits a connection request via a wireless modem, the connection request is translated into a network layer registration message, which is sent to the AP over the airlink. The AP needs to decide whether to allow this new connection request. The authorization control technique can be as simple as allowing any new connection request if the total number of allowed connections is less than the maximum. However, simple authorization control techniques cannot guarantee the quality of service for all authorized users, and as a result cannot increase bandwidth utilization.
【0147】
Therefore, other permit control techniques may be better than simple methods. Certain authorization control programs can even utilize a combination of several techniques. For example, if each connection request specifies a delay condition, a bandwidth condition, and a traffic descriptor, the AP will first allow the new connection to ensure the quality of service of the connection already allowed. Various performance measures (eg, total bandwidth consumed, average delay time) can be calculated to determine if unsatisfied. If you allow the new connection and the quality of service of all the connections already allowed is maintained, then the new connection is allowed. Otherwise, the new connection request will be rejected. KM Rege's Equivalent Bandwidth and Related Admission Criteria for ATM Systems International Journal of Communication Equivalent bandwidth-related authorization techniques described in Systems, Volume 2, pp. 181-197 (1994) can be used by making minor modifications to address this issue in wireless environments. For example, Rege assumes that there is only one bandwidth condition and only one set of QoS conditions. Here, Rege's method is extended to support multiple bandwidth requirements for uplink / downlink and different QoS conditions. Adjustments to bandwidth requirements are also supported based on the radio distance between the wireless modem and the AP and, therefore, the FER that may be experienced.
【0148】
In another example, each connection request specifies the required average bit rate and traffic burst factor. The AP collects information about the number of bytes transmitted by each connection in both directions over a period of time. The AP also measures the burst factor for connection traffic in both directions. Based on this measured information, the AP can determine the bit rate of potential average connections in both directions (uplink / downlink) and the burst factor of each connection. The AP then calculates the equivalent number of allowed connections. When a new connection request arrives, the AP calculates whether the new equivalent number of allowed connections exceeds the specified threshold. If the threshold is exceeded, the connection request will be rejected. If not, it is acceptable.
【0149】
The quantity measured may be various measures associated with interference. If this was a jamming limit system rather than a bandwidth limiting system, the AP would frame to each remote host based on the measured jamming to know if the new connection should be allowed. Measure the error rate (FER) measure. An embodiment of this method for allowing new connections based on the measured quantity in the wireless network is shown in FIG. Uplink frame error rate, uplink average bit rate, uplink traffic burst factor, and packet loss rate will be measured at the base station for each remote host in 2010. The downlink frame error rate, the average downlink bit rate, the downlink traffic burst factor, and the packet loss rate were measured at each allowed remote host in 2015, followed by the downlink. FER will be sent to the base station in 2020. This procedure continues in 2025, allowing all currently authorized remote hosts to send their FER measurements to the base station. The reporting process can be either regular or triggered. In one alternative embodiment, each remote also sends the average downlink bit rate, traffic burst factor, and packet loss rate to the base station.
【0150】
Equivalent bandwidth is calculated at the base station for each remote host in 2030 based on the average and peak bit rates of that connection, the burst burst factor of traffic, and the packet loss rate of each connection. These calculations are constantly communicated from new information received from the remote host and are used by the base station to calculate the equivalent number of connections already allowed in 2040. If a new connection is requested in 2045, the base station considers the effect of the average rate and packet loss rate required by the requested connection based on the equivalent bandwidth and everything allowed in 2050. Calculate in 2050 whether the quality of service of a connection can be maintained even if the new connection is allowed. If it is determined in 2055 that QoS can be maintained, the new connection will be granted in 2060, otherwise the new connection will be denied permission in 2065.
【0151】
Strict use priority authorization criteria can also be implemented. For example, if you have two user priority classes, namely class 1 and class 2, the system will maximize K for users with the lower priority class 2.<sub>1</sub>Only allow and the total number of users is M (M K)<sub>1</sub>). When the AP receives a connection request from one of the new class 1 users, the current number of associated users, k<sub>m</sub>Make a decision based on. k<sub>m</sub>If M, allow new class 1 users. If not, check if any of the Class 2 users can be detached. If it can be detached, the AP detaches one of the class 2 users and allows the new class 1 user.
【0152】
In this usage priority permission method, there are two methods for permitting the user with the lower priority. If the system performance condition is such that it is appropriate to disconnect after the lower priority user is allowed, the lower priority user has a total of M associated users. Only allowed if smaller. However, when a new class 1 user appears, the AP will send a detach message to one of the already allowed class 2 users to allow the new user in that class. In one embodiment, the "least recently used" technique is used to identify already allowed Class 2 users that the AP will disconnect.
【0153】
If the performance requirements of the system are such that it is inappropriate to disconnect after the lower priority user is allowed, the AP allows class 2 users in the following ways: k<sub>m</sub>If <M and the new user is a Class 2 user, then the AP is the number of Class 2 associated users, i.e. I.<sub>m</sub>But I<sub>m</sub><K<sub>2</sub>Is determined. I<sub>m</sub><k<sub>2</sub>If, then the new user of class 2 is allowed. Otherwise, the new user of class 2 will not be allowed. This method can be extended to multiple priority classes.
【0154】
FIG. 19 is a flowchart showing a specific example of controlling the authorization of the remote host according to one aspect of the present invention. The network of the embodiment of FIG. 19 supports at least two priority classes of remote hosts, and the maximum total number of remote hosts allowed, and the lower priority of the allowed number of remotes. It has both maximum values. When a base station receives a connection request from a remote host that is not yet authorized in 1910, the base station determines in 1915 whether the host belongs to the higher priority class. If so, if the number of allowed remote hosts is determined in 1920 to be less than the maximum total number of remote hosts, then the higher priority host that has not yet been allowed is Permitted in 1925. If it is determined in 1920 that the total number of remote hosts allowed is not less than the maximum total number of remote hosts, then the lower priority class is already allowed.If it is determined in 1930 that no remote host is available, the requesting host is denied permission in 1935. If one of the hosts already allowed in 1930 was a host of the lower priority class, and if it was determined in 1940 that it indicated that it was detachable at the time it was allowed, then that lower. The remote host of the higher priority class is detached in 1945, allowing the requesting remote host from that higher priority class to be allowed in 1925. In one embodiment, it is preferred that the least recently used remote host of the lower priority classes be disconnected. If the connection request received at the base station in 1910 is determined in 1915 to be from a remote host that belongs to the lower priority class and is not yet authorized, then the authorized remote host Indicates that if the total number of is determined in 1950 to be less than the maximum number allowed, and the requesting lower priority remote host can be disconnected in an under-processed state. If determined in 1955, the lower priority host is allowed in 1925. If the total number of allowed remote hosts is determined in 1950 to be less than the maximum, and the lower priority remote host that has not yet been allowed is improperly detached in the middle of processing. If determined in 1955 to indicate, the lower priority remote host is determined in 1960 that the number of lower priority hosts already allowed is less than a certain threshold. Only allowed in 1925 if done. Otherwise, the requesting lower priority host is denied permission in 1935. This is as if the total number of allowed users was determined in 1950 to be no less than the maximum allowed.
【0155】
In an alternative embodiment of this authorization control technique, users in the lower priority class (eg, users in class 2) have a second threshold of the total number of users in all currently associated classes. Allowed if less than the value. The second threshold is usually not based in part (as the second threshold) on the number of currently associated users of the lower priority class, but the higher one. Less than the threshold for priority users. In this embodiment, the total number of currently associated users is Q<sub>i</sub>If it was smaller (Q<sub>i + 1</sub><Q<sub>i</sub>And Q<sub>i</sub>= M), new users from priority class i are allowed.
【0156】
In one embodiment, the AP collects the following information for each connection: (i) Average usage rate, (ii) Time when the connection last used the network, (iii) Frame error rate, (iv) Packet loss rate. The overload control method then allows the AP to isolate the lower priority user when it is crowded. Instead of detaching the lower priority users, they can be redirected to other nearby APs with less load.
【0157】
If the downlink / uplink buffer occupancy exceeds the higher threshold, the access point determines, in a preferred embodiment, whether this was caused by a particular connection or group of connections. To do. If it is caused by a particular connection, the access point sends a flow control signal to that connection, preventing it from sending further data. In addition, the access point can reduce the sharing of the allocated bandwidth to any user who indicated during connection setup that the allocated bandwidth can be variable.
【0158】
If the downlink frame error rate readings for many connections are found to be increasing, the AP may have increased levels of interference from other access points. All authorized users can generally be divided into two categories. They allow and do not allow interruptions in service. Allows access points to allocate more bandwidth to the remaining users with a class of authorized users that allows service interruptions when crowded due to increased levels of disruption. You can choose to disconnect to make it (more bandwidth available can increase opportunities for retransmissions).
【0159】
If only one particular connection is getting higher in its downlink frame error rate, then that access point is getting worse if its performance is getting worse and the connection has the higher priority. You can choose to disconnect other connections. For example, when a particular higher priority connection has a higher frame error rate on its uplink, the access point gives more bandwidth to that higher priority connection. Therefore, other users can be separated. If most of all associated connections have a high error rate for their uplink frame, the AP will instead send a crowded signal to the wireless hub, which will be the other access point. You can adjust the action of. It can be done, for example, by sending a signal to these access points to prevent them from accepting new users and dropping lower priority users.
【0160】
There can also be opportunities for sudden increases in short burst messages. If short packets on either the uplink or downlink queue at that access point are queued for a long time and exceed the lifetime value assigned to them, they are discarded and the result is As the packet loss rate increases to handle the bottleneck at that access point. In such overloaded conditions, the access point may choose to temporarily disconnect some low-priority users. Other combinations of possible actions described may also be appropriate. The exact combination determined by the base station depends on the particular complexity observed in the network.
【0161】
Specific embodiments of the method for overload control are shown in the flowchart of FIG. As can be seen in Figure 21, the uplink frame error rate is 2110 for each remote node based on the average uplink bit rate, uplink traffic burst factor, and packet loss rate. It is constantly measured. Similarly, the downlink frame error rate is measured at 2115 based on the downlink average bit rate, downlink traffic burst factor, and packet loss rate at each remote host, and then each FER is sent to the base station at 2110. This procedure continues at 2125 and all currently authorized remote hosts can send their respective FERs to the base station. In the presence of an overload condition, a flow control message is sent on the 2130 to control the data flow between at least one remote host and the base station. If a packet in the base station is determined to exceed the lifetime threshold in 2135, the packet is dropped in 2140 and the frame error rate threshold is set to the frame for the specified time. Connections determined in 2145 that the error rate is exceeded, and connections determined in 2150 that indicate that those connections may be interrupted, are disconnected in 2155.
【0162】
To obtain a particular quality of service, each connection request contains the following information: They are traffic descriptors consisting of bandwidth requirements, delay time conditions, "loss allowed / prohibited" tags, "service interruption allowed" flags, acceptable packet loss rates, and peak data rates, average data. Rate and potential burstability factor for each direction, ie, uplink and downlink directions. For example, a connection with a delay condition of 20 ms and with "Leave Tolerance" specified has the message it sends, or the message it expects to receive, in the queue at its wireless modem or access point. If the packet has been in for more than 20ms, the packet will be discarded. If the user specifies a delay condition, but classifies it as "no loss", then packets destined for that user are not discarded until a buffer overflow occurs. Bandwidth requirements, delay conditions, packet loss rates, and traffic descriptors are all used in authorization control techniques.
【0163】
Data security features can be implemented using any method known in the art of this field. One example is to adopt a method equivalent to the Institute of Electrical and Electronics Engineers (IEEE) standard 802.11 Wired Local Area Network (LAN). Its Wired Equivalent Privacy (WEP) feature is defined in the 802.11 standard to protect authorized users from inadvertent eavesdropping on wireless LANs. Payload encryption is not turned on unless the WEP option is turned on. Each service provider assigns a key that is shared to all users, in addition to a user-specific key. The key is changed on a regular basis, and the length of the selected key and the frequency with which the key is changed make the security function effective.
【0164】
Preferable embodiments of the new access control and permission control and conflict resolution schemes are described above, but these embodiments are intended and are not limited thereto. .. In light of the above, it is possible that minor modifications and variants may be made by someone who is proficient in the art of this field. Therefore, it should be understood that such modifications made with respect to certain embodiments of the invention disclosed are within the scope and spirit of the invention as defined by the claims. Although the present invention has been described with the details and specificity required by patent law, the claims and claims to be protected by Letters Patent are described in the appended claims. ing.
[Simple explanation of drawings]
[Figure 1]
It is a schematic diagram of the network of the prior art.
[Figure 2]
It is the schematic of the network by one aspect of this invention.
[Fig. 3]
It is a frame diagram which shows the example of the frame structure of the downlink and the uplink for the embodiment of the frequency division multiplexing system of this invention.
[Fig. 4]
It is a frame diagram which shows the example of the frame structure of the downlink and the uplink for the embodiment of the frequency division multiplexing system of this invention.
[Fig. 5]
FIG. 5 is a frame diagram of a synchronized downlink and uplink frame structure for an embodiment of the frequency division multiplexing system of the present invention.
[Fig. 6A]
A frame containing a broadcast subframe of a common MAC layer downlink according to one embodiment of the present invention is shown.
[Fig. 6B]
Indicates the format of broadcast or multicast downlink frames.
[Fig. 6C]
The format of the beacon message for the embodiment of FIG. 6B is shown.
[Fig. 6D]
The transmission permission format for the embodiment of FIG. 6B is shown.
[Fig. 6E]
The format of the transmission schedule for the embodiment of FIG. 6B is shown.
[Fig. 6F]
The format of the broadcast or multicast payload for the embodiment of Figure 6B is shown.
[Fig. 7A]
Shown is one frame having a downlink unicast subframe according to one embodiment of the present invention.
[Fig. 7B]
The format of the flow control frame for the downlink unicast data subframe according to one embodiment of the present invention is shown.
[Fig. 7C]
The format of the data frame for the downlink unicast data subframe according to one embodiment of the present invention is shown.
[Fig. 7D]
Indicates a unicast subframe that is concatenated after the broadcast subframe.
[Fig. 8A]
A frame format for an uplink transmission frame according to one embodiment of the present invention is shown.
[Fig. 8B]
Figure 8A shows the asynchronous transfer area of the frame.
[Fig. 8C]
An uplink frame having a reserved minislot according to one embodiment of the present invention is shown.
[Fig. 8D]
A frame format for a reserved minislot according to one embodiment of the invention is shown.
[Fig. 8E]
Demonstrates a frame format for a pure acknowledgement uplink frame according to one embodiment of the invention.
[Fig. 8F]
A frame format for a pure data uplink unicast frame according to one embodiment of the invention is shown.
[Fig. 8G]
A frame format for a combination of acknowledgement and data uplink frames according to one embodiment of the present invention is shown.
[Fig. 8H]
A frame format for a combination of acknowledgement, data, and "more" uplink frames according to one embodiment of the invention is shown.
[Fig. 9A]
In one embodiment of the invention, a timeline showing a packet tag at time t = 0 is shown.
[Fig. 9B]
The time line showing the tag of the packet at the time t = 3 immediately before the arrival of session 3 in the example of FIG. 9A is shown.
[Fig. 9C]
In the example of FIG. 9A, a timeline showing the packet tags at time t = 3 immediately after the 9 packets from the arrival of session 3 is shown.
[Fig. 9D]
In the example of FIG. 9A, a time line showing the tag of the packet at time t = 4.5 is shown.
[Fig. 10]
It is a figure which shows the dynamic adjustment of the uplink / downlink ratio by one Embodiment of this invention.
[Fig. 11]
It is the schematic which shows the operation of the paging function of one Embodiment of this invention.
[Fig. 12A]
FIG. 5 is a flow chart illustrating different methods that can be used to dynamically change the number of reserved minislots according to one embodiment of the invention.
[Fig. 12B]
FIG. 5 is a flow chart illustrating different methods that can be used to dynamically change the number of reserved minislots according to one embodiment of the invention.
[Fig. 12C]
FIG. 5 is a flow chart illustrating different methods that can be used to dynamically change the number of reserved minislots according to one embodiment of the invention.
[Fig. 12D]
FIG. 5 is a flow chart illustrating different methods that can be used to dynamically change the number of reserved minislots according to one embodiment of the invention.
[Fig. 13A]
It is a flowchart which shows the operation of the comprehensive MAC protocol when viewed from the remote host by one Embodiment of this invention.
[Fig. 13B]
It is a flowchart which shows the operation of the comprehensive MAC protocol when viewed from the base station by one Embodiment of this invention.
[Fig. 14A]
It is a flowchart which shows three conflict-solving methods by embodiment of this invention.
[Fig. 14B]
It is a flowchart which shows three conflict-solving methods by embodiment of this invention.
[Fig. 14C]
It is a flowchart which shows three conflict-solving methods by embodiment of this invention.
[Fig. 15A]
It is a flowchart which shows one Embodiment of the method for sharing the bandwidth of this invention.
[Fig. 15B]
It is a flowchart which shows the alternative embodiment of the method for sharing the bandwidth of this invention.
[Fig. 16]
It is a flowchart which shows the allocation of the packet service tag by one Embodiment of this invention.
[Fig. 17]
It is a flowchart which shows establishment of the power level for transmission of uplink data according to one aspect of the method of this invention.
[Fig. 18A]
It is a flowchart which shows one Embodiment of the method for access control by this invention.
[Fig. 18B]
It is a flowchart which shows the alternative embodiment of the method for access control by this invention.
[Fig. 19]
It is a flowchart which shows one Embodiment of the method for controlling the authorization of a remote host by this invention.
[Fig. 20]
It is a flowchart which shows one embodiment of the method of allowing a new connection based on the measured quantity according to one aspect of the present invention.
[Fig. 21]
It is a flowchart which shows one embodiment of the method for overload control in a network according to one aspect of this invention.
[Fig. 22]
It is a block diagram of the on-demand multiplex access system by fair queuing of this invention.
[Fig. 23]
It is a flowchart which shows the operation of the multiple access system of this invention.
50 sheets
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Every citation, both ways
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| JP8279816A | Cites | Japan |
101 members in 8 offices
Priority claims6
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|---|---|---|---|
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| 60077741 | United States of America | – | |
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| 09083762 | United States of America | – | |
| 8376298 | United States of America | A |
Members101
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| CA2249819A1 | Canada | A1 | |
| CA2249840A1 | Canada | A1 | |
| CA2249864A1 | Canada | A1 | |
| CA2249865A1 | Canada | A1 | |
| CA2249866A1 | Canada | A1 | |
| CA2249868A1 | Canada | A1 | |
| EP0910176A2 | European Patent Office (EPO) | A2 | |
| EP0912015A2 | European Patent Office (EPO) | A2 | |
| EP0912016A2 | European Patent Office (EPO) | A2 | |
| EP0912015A3 | European Patent Office (EPO) | A3 | |
| EP0913968A1 | European Patent Office (EPO) | A1 | |
| EP0915592A1 | European Patent Office (EPO) | A1 | |
| EP0917316A2 | European Patent Office (EPO) | A2 | |
| EP0917317A1 | European Patent Office (EPO) | A1 | |
| IL126520A0 | Israel | A0 | |
| IL126521A0 | Israel | A0 | |
| IL126522A0 | Israel | A0 | |
| IL126523A0 | Israel | A0 | |
| IL126524A0 | Israel | A0 | |
| IL126525A0 | Israel | A0 | |
| IL126526A0 | Israel | A0 | |
| JPH11261623A | Japan | A | |
| JPH11289339A | Japan | A | |
| JPH11289340A | Japan | A | |
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| JPH11298532A | Japan | A | |
| JPH11298533A | Japan | A | |
| EP0912016A3 | European Patent Office (EPO) | A3 | |
| EP0917316A3 | European Patent Office (EPO) | A3 | |
| CA2281453A1 | Canada | A1 | |
| CA2281454A1 | Canada | A1 | |
| CA2281456A1 | Canada | A1 | |
| EP0994603A2 | European Patent Office (EPO) | A2 | |
| EP0994604A2 | European Patent Office (EPO) | A2 | |
| EP0994634A2 | European Patent Office (EPO) | A2 | |
| KR20000029041A | Republic of Korea | A | |
| KR20000034991A | Republic of Korea | A | |
| KR20000034996A | Republic of Korea | A | |
| JP2000188784A | Japan | A | |
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| AR013543A1 | Argentina | A1 | |
| AR013685A1 | Argentina | A1 | |
| AR013977A1 | Argentina | A1 | |
| EP0994634A3 | European Patent Office (EPO) | A3 | |
| AR015181A1 | Argentina | A1 | |
| US6226277B1 | United States of America | B1 | |
| AR016958A1 | Argentina | A1 | |
| EP0910176A3 | European Patent Office (EPO) | A3 | |
| US6285665B1 | United States of America | B1 | |
| AR017328A1 | Argentina | A1 | |
| AR017329A1 | Argentina | A1 | |
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| CA2281456C | Canada | C | |
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| EP0994603B1 | European Patent Office (EPO) | B1 | |
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| EP0917316B1 | European Patent Office (EPO) | B1 | |
| DE69838775D1 | Germany | D1 | |
| DE69838775T2 | Germany | T2 | |
| EP0915592B1 | European Patent Office (EPO) | B1 |
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Numbers
- Publication
- 3477086
- Publication, DOCDB
- 3477086
- Publication, EPODOC
- JP3477086B
- Application
- 29124898
- Application, DOCDB
- 29124898
- Application, EPODOC
- JP19980291248
Titles2
- Japanese
- 【発明の名称】通信ネットワークのための多重アクセス・システムにおいて、測定された量に基づいて新しいコネクションを許可するための方法
- English
- INDUSTRIAL APPLICABILITY A method for allowing a new connection based on a measured quantity in a multiple access system for a communication network.
Classification
- CPC, 28
- H04L47/805
- H04L43/00
- H04L43/0829
- H04L43/0847
- H04L43/0888
- H04L43/16
- H04L47/15
- H04L47/286
- H04L47/30
- H04L47/32
- H04L47/788
- H04L47/822
- H04L47/824
- H04W28/22
- H04W28/24
- H04W52/10
- H04W52/50
- H04W88/08
- H04W92/02
- H04L47/70
- H04W76/30
- H04W28/02
- H04W72/543
- H04W72/542
- H04W72/56
- H04L47/26
- H04L47/10
- H04W8/04
- IPC, 21
- H04J1 00
- H04B7 005
- H04B7 24
- H04J3 00
- H04J3 16
- H04L12 28
- H04L12 56
- H04L69 14
- H04M3 00
- H04W24 00
- H04W28 04
- H04W28 08
- H04W28 22
- H04W28 24
- H04W52 10
- H04W52 50
- H04W72 00
- H04W72 10
- H04W76 06
- H04W88 08
- H04W92 02
