Method and apparatus for data packet transport in wireless communication system using internet protocol

[Priority claim under 35U.S.C120]

This patent application was filed on October 3, 2001, transferred to the transferee, and incorporated herein by reference, "Methods and Devices for Data Packet Transmission in Wireless Communication Systems Using the Internet Protocol. It is a partial continuation application of Patent Application No. 010556 entitled "and Appliance for Data Packet Transport in a Wireless Communication System Using an Internet Protocol", and claims priority over this application. The present invention relates generally to wireless communication systems, particularly to methods and devices for message compression in preparation for transmission in wireless communication systems.

The demand for packetized data services in wireless communication systems is increasing. Since traditional wireless communication systems are designed for voice communication, there are many difficulties in extending them to support data services. Bandwidth maintenance is an overwhelming concern for the majority of designers. In one-way transmission such as broadcast transmission, a single broadcast content is supplied to a large number of users. These users are identified by a unique identifier contained in the addressing information. In such a system, a large number of infrastructure elements may be required to copy the broadcast packet to identify each of the large number of intended recipients. Copying the transmitted signal uses a lot of valuable bandwidth to reduce the efficiency of the communication system and increase the processing requirements of the intermediate backbone element. Especially for broadcast services, the number of target recipients can be quite large, causing problems of resource allocation and loss of available bandwidth.

Therefore, there is a need for an efficient and highly accurate method of transmitting data to a large number of recipients in a wireless communication system. Further, there is also a need for a method of route selection of broadcast data to a large number of users, in which each user is uniquely identified as a target recipient.

[Overview]

The embodiments disclosed herein address the aforementioned need by providing a method for routing IP packets in a wireless communication system in which a broadcast service or other point-to-multipoint service is performed intermittently. It is a thing. The intermittent broadcast service is transmitted when the trigger to start the service is recognized, and is not transmitted when the trigger to end the service is recognized. Intermittent broadcast services thus maintain bandwidth and other transmission resources in the system. In one embodiment, transmission on a radio interface to a mobile station and / or other radio device may include a unicast or multicast transmission line. When the number of active users per group call at a given transmission node exceeds a certain threshold, the call is transmitted on a common channel, such as a broadcast channel. When the number of active users is within the threshold, the call is sent on a dedicated channel to each participant serviced by that transmission node. In one embodiment, the packet is routed to an access network that uses a multicast address.

In one aspect, in a radio communication system that has a broadcast source node and at least one broadcast transmission node and supports broadcast transmission, the method is to recognize the broadcast trigger at the broadcast transmission node and to broadcast from the broadcast source node. This includes establishing a broadcast transmission path to the transmission node, sending a broadcast message to the broadcast transmission node via the broadcast transmission path, and transmitting the broadcast message from the broadcast transmission node.

In another aspect, the wireless device is a processing unit and a storage device connected to the processing unit, (1) for recognizing a broadcast trigger at a broadcast transmission node and (2) from the broadcast source node. To establish a broadcast transmission path to a broadcast transmission node, (3) to send a broadcast message to the broadcast transmission node via the broadcast transmission path, and (4) to transmit the broadcast message from the broadcast transmission node. , A storage device adapted to store a plurality of instructions, and the like.

In yet another aspect, in a wireless communication system that has a source node and at least one transmission node and supports group call transmission, the method is to initiate a first group call and an active user with respect to the group call. To determine the first number of, to send the group call on the broadcast channel when the first number exceeds the threshold, and at least one if the first number does not exceed the threshold. The group call is transmitted on one dedicated channel, and the at least one dedicated channel enables point-to-point communication between the at least one transmission node and an active user.

[Detailed description]

The term "exemplary" is used herein to mean "useful as an example, case or illustration" in a limited way. Any embodiment described herein as "exemplary" should not necessarily be construed as more preferred or advantageous over other embodiments.

Efficient use of available bandwidth has a significant impact on system performance and breadth. To that end, various techniques have been applied to reduce the size of overhead information transmitted with data or content information. For example, in some digital transmissions, data is transmitted in frame format. Typically, one frame of information contains header information, data payload information, and a terminating part. These frames can be part of a packet of data or part of a data message or contiguous frames within a stream of information such as audio and / or video streams. Each frame of data (and each packet or message) is accompanied by a header that contains processing information that makes the information contained in the frame understandable to the recipient. This header information is regarded as overhead, that is, processing information transmitted together with the information content. Information content is called the payload.

Data frames are transmitted throughout the communication system via various mission-critical facility elements. In traditional systems, sending information to a large number of users requires duplication of information at a central packet data control point, such as a Packet Data Service Node (PDSN). This replication increases the processing requirements of the PDSN and wastes valuable bandwidth. For example, a given system extension may require routers and trunks in close proximity to the PDSN to be large enough to handle double traffic. The PDSN sends a large number of copies to the base station, which transfers this information to each user. The conventional method is particularly disadvantageous in a one-way broadcast service in which a large number of users receive broadcast transmissions. The PDSN in this case must make a large number of copies, give each copy a unique address, and send these copies individually.

The PDSN is typically required to provide additional header information that identifies each target recipient. For broadcast services, the number of target recipients can be quite large, which causes problems (resource allocation and loss of available bandwidth.

An exemplary embodiment of a wireless communication system uses a method of data transmission that reduces the bandwidth used by mission-critical facility elements while satisfying system accuracy and transmission requirements. In this exemplary embodiment, replication is BS or Packet Control (PCF; Packet Control). Function) Releases the PDSN or central packet data router to send messages with multicast headers to each BS or PCF involved in broadcasting on the node. For example, a message travels through a Multi-Cast (MC) tree to the PCF, where the PCF copies the message for each BSC and then a separate Unicast (UC) connection. Send each message through a connection or secure tunnel created between the PCF and a particular BSC. Note that a UC connection can be a point-to-point connection. This exemplary embodiment supports a one-way broadcast service. This broadcast service provides video and / or audio streams to a large number of users. Subscribers to this broadcast service "tune the receiver" to the channel designated to access this broadcast transmission. Due to the high bandwidth requirements for high-speed transmission of video broadcasts, it is desirable to reduce the amount of replication on hops in the network and the amount of replication packets transmitted.

The discussion below develops this exemplary embodiment by first presenting a spectrally diffused wireless communication system in general. Next, the broadcasting service will be introduced. This service is referred to herein as the High Speed Broadcast Service (HSBS), and the discussion includes channel allocation in this exemplary embodiment. It then presents a subscription model that includes options for paid subscriptions, free subscriptions, and hybrid subscriptions that are similar to the subscription models currently available for television transmission. How to access the broadcast service is detailed and presents the usage of service options to define the details of a given transmission. The message flow in this broadcasting system is discussed regarding the topology of the system, that is, the topology of the core facility elements. Finally, the header compression used in this exemplary embodiment is discussed.

Note that this exemplary embodiment is given as a sample throughout this discussion. However, alternative embodiments can incorporate various aspects without departing from the scope of the invention. In particular, the present invention is applicable to data processing systems, wireless communication systems, one-way broadcasting systems, and other systems that require efficient transmission of information.

Radio Communication System This exemplary embodiment uses a spectral diffusion radio communication system that supports broadcasting services. Wireless communication systems are widely deployed to provide various types of communication such as voice, data and the like. These systems can be based on Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), or several other modulation techniques. CDMA systems offer several advantages over other types of systems, including increased system capacity.

The system is the "TIA / EIA / IS-95-B mobile station-base station compatibility standard for dual-mode wideband spectral diffusion cellular system" here called the IS-95 standard and the "third generation joint" here called 3GPP. Proposed by a joint venture named "Project", which includes document numbers 3GTS25.211 and 3GTS25.212 and 3GTS25.213 and 3GTS25.214 and 3GTS25.302, which are referred to here as W-CDMA standards. A standard embodied in a set of documents, a standard proposed by a joint venture named "Third Generation Partnership 2" here called 3GPP2, and formerly called IS-2000MC, here It may be designed to support one or more standards, such as TR-45.5, called the cdma2000 standard. These standards cited above are clearly incorporated herein by reference.

Each standard defines in detail the processing of data for transmission from a base station to a mobile station and vice versa. As an exemplary embodiment, the discussion below considers a spectral diffusion communication system that is consistent with the cdma2000 standard protocol. Alternative embodiments may incorporate other standards. Yet another embodiment can apply the compression schemes disclosed herein to other types of data processing systems.

FIG. 1 is an example of a communication system 100 that can support a large number of users and realize at least some aspects and embodiments of the present invention. Any of a variety of algorithms and methods can be used to schedule transmissions in system 100. System 100 provides communication for a large number of cells 102A-102G, each serviced by the corresponding base stations 104A-104G. In this exemplary embodiment, some base stations 104 have a large number of receiving antennas and other base stations have only one receiving antenna. Similarly, some base stations 104 have a large number of transmitting antennas, while others have a single transmitting antenna. There are no restrictions on the combination of the transmitting antenna and the receiving antenna. Therefore, a base station 104 has a large number of transmitting antennas and one receiving antenna, or has a large number of receiving antennas and one transmitting antenna, or has one transmitting antenna and one receiving antenna. Alternatively, it is possible to have a large number of transmitting antennas and receiving antennas.

The terminal 106 in the coverage area may be fixed (ie stationary) or movable. As shown in FIG. 1, various terminals 106 are dispersed in this system. Each terminal 106 depends, for example, on whether soft handoff is used or whether the terminal is designed and operated to receive a large number of transmissions (simultaneously or sequentially) from a large number of base stations. Communicate with at least one, perhaps two or more, base stations on the downlink and uplink at any given moment. Soft handoffs in CDMA communication systems are well known to those skilled in the art and have been transferred to the transferees of the present invention, "Method and System for providing a Soft. It is detailed in US Pat. No. 5,101,501 entitled "Handoff in a CDMA Cellular Telephone System)".

Downlink refers to transmission from the base station to the terminal, and uplink refers to transmission from the terminal to the base station. In this exemplary embodiment, some terminals 106 have a large number of receiving antennas and other terminals have only one receiving antenna. In FIG. 1, base station 104A transmits data to terminals 106A and 106J by downlink, base station 104B transmits data to terminals 106B and 106J, and base station 104C transmits data to terminal 106C. The same is true.

The increasing demand for wireless data transmission and the expansion of services available through wireless communication technologies have led to the development of unique data services. One such service is called High Data Rate (HDR). An exemplary HDR service is proposed in the "EIA / TIA-IS856 cdma2000 High Rate Packet Data Air Interface Specification" called the "HDR Specification". HDR services are generally an overlay on voice communication systems that provide an efficient way to transmit packets of data in wireless communication systems. As the amount of data transmitted and the number of transmissions increase, the limited bandwidth available for wireless transmission becomes a critical resource. Therefore, there is a need for an efficient and standards-based method of scheduling transmissions in communication systems that optimize the use of available bandwidth. In this exemplary embodiment, the system 100 shown in FIG. 1 is consistent with a CDMA type system having HDR services.

High Speed Broadcast System (HSBS) Figure 2 shows the wireless communication system 200, where video and audio information is supplied to the Packet Data Service Node (PDSN) 202. This video and audio information can be from television program broadcasts or from wireless transmission. Information is supplied as packetized data such as IP packets. PDSN202 processes IP packets for distribution within an access network (AN). As shown, AN is defined as part of a system that includes BS204, which communicates with a number of MS206s. PDSN202 is connected to BS204. For the HSBS service, the BS204 receives a stream of information from the PDSN202 and supplies this information to the subscribers in the system 200 on the designated channel.

In a given sector, there are several ways in which HSBS broadcasting services can be deployed. Factors involved in designing the system include, but are not limited to, the number of HSBS sessions supported, the number of frequency assignments, and the number of physical channels of broadcasting supported.

HSBS is an information stream supplied by the wireless interface of a wireless communication system. HSBS channel refers to a single logical HSBS broadcast session as defined by the broadcast content. Keep in mind that the content of a given HSBS channel can change over time, for example, 7am news, 8am weather forecast, 9am movie, and so on. Time-based scheduling is similar to a single TV channel. "Broadcast channel" refers to a single forward link physical channel, a predetermined Walsh code that carries broadcast traffic. Broadcast channel BCH corresponds to a single Code Division Multiplex (CDM) channel.

A single broadcast channel can have one or more HSBS channels, in which case the HSBS channels will be multiplexed within a single broadcast channel by time division multiplexing (TDM). .. In one embodiment, a single HSBS channel is provided on two or more broadcast channels within a sector. In another embodiment, a single HSBS channel is provided on different frequencies to serve subscribers at these frequencies.

According to this exemplary embodiment, the system 100 shown in FIG. 1 supports a high-speed multimedia broadcasting service called a high-speed broadcasting service (HSBS). The broadcast capabilities of this service are intended to deliver programs at sufficient data rates to support video / audio communications. As an example, HSBS service applications may include video streams such as movies, sporting events, etc. The HSBS service is a packet data service based on the Internet Protocol (IP).

According to this exemplary embodiment, a content server (CS) advertises the availability of such high-speed broadcasting services to system users. Any user who wants to receive the HSBS service can sign up for CS. Subscribers can then view the broadcast service schedules that CS can provide in a variety of ways. Broadcast schedules are, for example, via various advertisements, Short Management System (SMS) messages, Wireless Application Protocol (WAP), and / or other means that are generally compatible with mobile wireless communications and are convenient. Can be transmitted. Mobile users are called mobile stations (MS). Base station (BS; Base) Station) sends HSBS-related parameters in overhead messages, such as messages transmitted over the channels and / or frequencies specified for control and information, ie non-payload messages. The payload refers to information content of transmission, and for a broadcast session, the payload is broadcast content, such as a video program. When a broadcast service subscriber wants to receive a broadcast session, a program with a particular broadcast schedule, the MS reads the overhead message to find out the proper configuration. The MS then receives the broadcast service content to a frequency that includes the HSBS channel.

The channel structure of this exemplary embodiment conforms to the cdma2000 standard in which forward supplement channels (F-SCHs) support data transmission. One embodiment is a number of Forward Fundamental Channels (F-FCH) or Forward Dedicated Control Channels (F-DCCH) to meet the faster data velocity requirements of a data service. Is bundled. This exemplary embodiment utilizes F-SCH as a base for F-BSCH supporting a payload of 64 kbps (excluding RTP overhead). F-BSCH can also be modified to support other payload speeds, for example by splitting the 64kbps payload speed into slower substreams.

One embodiment also supports one-to-many (1-to-M) multicast applications, including, but not limited to, group calls in several different ways. For example, by using an existing unicast channel, namely F-FCH (or F-DCCH), one forward link channel per MS without sharing, on both forward and reverse links. In another embodiment, F-SCH (shared by group members in the same sector) and F-DCCH (most of the time have no frames other than the forward power control subchannel) on the forward link, R-DCCH on the reverse link is applied. In yet another embodiment, a high speed F-BSCH on the forward link and an access channel (or enhanced access channel / reverse common control channel combination) on the reverse link are utilized.

With high data rates, the Forward Broadcast Supplemental Channel (F-BSCH) of this exemplary embodiment is a very large portion of the base station's forward link power to provide sufficient coverage. Can be used. In this way, HSBC's physical layer design focuses on improving efficiency in the broadcast environment.

To provide adequate support for video services, the system design takes into account the base station power required for the channels as well as the various methods for transmitting the corresponding video quality. One aspect of this design is the subjective trade-off between the video quality perceived at the edge of coverage and the video quality in the vicinity of the cell site. As the payload rate decreases and the effective error correction code rate increases, a given level of base station transmit power will provide better coverage at the edge of the cell. For mobile stations located closer to the base station, channel reception will remain error-free and video quality will be degraded due to the reduced source speed. This same trade-off applies to other non-video applications that F-BSCH can support. Decreasing the payload speed supported by the channel increases coverage at the expense of the reduced download speed for these applications. The balance of relative importance between video quality and data throughput vs. coverage is objective. The configuration chosen looks for an application-optimized configuration and a good compromise among all possibilities.

Payload speed for F-BSCH is an important design parameter. The following assumptions can be used in designing a system that supports broadcast transmission according to this exemplary embodiment. That is, (1) the target payload speed is 64 kbps, which gives acceptable video quality. (2) For video stream services, the payload rate is assumed to include 12 bytes of 8 bits per packet overhead of an RTP packet. (3) The average overhead for all layers between the RTP and the physical layer is approximately 64 bytes per packet, plus 8 bits per FSCH frame used by the MUXPDU header.

In this exemplary embodiment, the maximum speed supported for non-video broadcast services is 64 kbps. However, many other possible payload speeds below 64 kbps are also achievable.

Subscription Models There are several possible subscription / revenue models for HSBS, including free and managed access and partially managed access. No subscription is required for free access to receive the service. BS broadcasts the content unencrypted, and interested mobile stations can receive the content. Revenue for service providers can be generated by advertising that can also be sent over broadcast channels. For example, a promotional clip for an upcoming movie can be transmitted, which the movie studio will pay for the service provider.

For controlled access, the MS user subscribes to the broadcast service and pays the corresponding fee. Unsubscribed users will not be able to receive the HSBS service. Managed access can be achieved by encrypting HSBS transmission / content so that only subscribed users can decrypt the content. It can use the wireless encryption key exchange procedure. This method provides strong security and prevents service theft.

A hybrid access scheme called partially managed access provides the HSBS service as an encrypted subscription-based service with intermittent unencrypted ad transmission. These advertisements may be intended to solicit subscription to encrypted HSBS services. The schedule of these unencrypted segments can be communicated to the MS through external means.

HSBS Service Options HSBS service options are defined by (1) a protocol stack, (2) options within this protocol stack, and (3) procedures for configuring and synchronizing services. The protocol stack according to this exemplary embodiment is shown in FIGS. 3 and 4. As shown in FIG. 3, this protocol stack is specific to the backbone element, i.e., MS, BS, PDSN, and CS in this exemplary embodiment.

Continuing with Figure 3, the protocol specifies an audio codec, a visual codec, and any visual profile for the MS application layer. In addition, this protocol specifies the Radio Transport Protocol (RTP) payload type when the Radio Transport Protocol (RTP) is used. For the MS transport layer, this protocol specifies the User Datagram Protocol (UDP) port. The security layer of the MS is specified by this protocol, where security parameters are provided over the out-of-band channel when this security is first combined with CS. The network layer specifies IP header compression parameters. According to one embodiment, the data packet is compressed at the link layer and then the appropriate framing protocol is applied to the compressed data.

Message Flow Figure 4 shows the call flow of one embodiment relating to a given system topology. This system includes MS, BS, PDSN and CS as listed on the horizontal axis. The vertical axis represents time. The user or MS is a subscriber to the HSBS service. At time t1, MS and CS negotiate subscription security for HSBS services. Negotiations include the exchange and maintenance of encryption keys and the like used to receive broadcast content on the broadcast channel. The user establishes a security tie-up with CS for receiving encrypted information. The encrypted information may include a broadcast access key (BAK) or key combination from CS and the like. According to one embodiment, the CS provides encrypted information over a dedicated channel during a packet data session via PPP, WAP or other out-of-band method.

At time t2, the MS begins receiving packets in sync with the broadcast channel. At this point, the MS cannot process the received packet because the IP / ESP header is compressed via ROHC and the MS decompressor is not initialized. The PDSN provides header compression information (details below) at time t3. From the ROHC packet header, the MS detects and acquires ROHC initialization & refresh (IR) packets that are periodically sent from the PDSN to the broadcast channel. ROHC IR packets are used to initialize the state of the decompressor in the MS, allowing the IP / ESP header of the received packet to be decompressed. The MS can then process the IP / ESP header of the received packet, but the MS has a short-term key (SK; Short-term) payload in the CS. Since it is encrypted with Key), it needs more information to process the ESP payload. This SK works in concert with the BAK, in which case the SK is decrypted at the receiver using the BAK. CS supplies additional encrypted information such as key information updated at time t4 or now SK. Keep in mind that CS will provide this information to MS on a regular basis to ensure the security of the broadcast in progress. At time t5, the MS receives the broadcast content from the CS. Alternative embodiments can also incorporate alternative compression / decompression schemes that provide efficient transmission of header information. Further alternative embodiments can implement various security schemes to protect broadcast content. Yet an alternative embodiment may also provide a non-security broadcast service. MS uses encrypted information such as SK to decrypt and display broadcast content.

Access network A schematic access network topology for System 300 with CS326 and two PDSN320s, 322s and PCF310s co-located PCFs, BSN312s and three BSC302s, 304s, 306s is shown in FIG. This CS326 is connected to PDSN320 and 322 via the IP cloud 324. IP Cloud 324 and IP Clouds 314, 308 are basically interconnected router configurations that form IP connection paths from CS to various recipients of data from CS. In the IP cloud 308, a virtual tunnel called an A8 tunnel is formed in order to transmit information from the PCF 310 to the BSC 302 and BSC 304. This tunnel can be a GRE tunnel. A protocol called A9 is used to establish the A8 tunnel. The IP cloud 308 may be labeled as the A8 / A9 cloud. In IP cloud 314, a virtual tunnel called A10 tunnel is formed to transmit information from PDSN320 to PCF310 and PCF / BSC312 respectively. Note that the PDSN320 to PCF310 will form an A10 tunnel and the PDSN320 to PCF / BSC312 will form a second A10 tunnel. These tunnels can be GRE tunnels. A protocol called A11 is used to establish the A10 tunnel. IP cloud 314 may be labeled as A10 / A11 cloud. One embodiment conforms to those specified in the cdma2000 and HDR standards described above. An access network (AN) is defined as an element and connection from a PDSN to an end user, such as an MS.

According to one embodiment, the broadcast CS326 sends an IP packet containing encrypted broadcast content to a multicast group identified by a class D multicast IP address. This address is used in the call receiving address field of IP packets. A given PDSN320 is involved in the multicast routing of these packets. After compression, the PDSN320 places each packet within an HDLC frame for transmission. This HDLC frame is generic routing encapsulation (GRE). Encapsulation) Encapsulated by packets. Note that GRE encapsulation forms the A10 tunnel mentioned above. The key field in the GRE packet header uses a specific value to indicate a broadcast bearer connection. A 20-byte IP packet header with a source address field that identifies the IP address of the PDSN320 is attached to the GRE packet, and a class D multicast IP address is used for the notification receiving address field. The multicast IP address is the same as that used by the original IP packet from CS326. Packets sent over the broadcast connection are delivered sequentially, enabling the GRE sequencing feature in one embodiment. The multicast-capable router copies IP multicast packets. According to an alternative embodiment, IP Cloud 314 provides point-to-point or unicast tunnels for individual recipients. The decision to use a multicast or unicast link for this connection point is made at a higher level, where the UC tunnel provides enhanced security and the MC tree provides efficiency.

According to an exemplary embodiment, the CS326 sends data to the PDSN320 via a multicast IP address, in which case the PDSN320 also sends data to the PCF310 and PCF / BSC312 over the multicast IP address. The PCF310 then determines, for example, the number of individual users in the active set within the call receiving subscription group and copies the frames received from CS326 for each of these users. The PDSN PCF310 determines the BSC (s) corresponding to each of the users in this enrollment group.

In one embodiment, the BSC 304 is adapted to send to the most recent BSC (s), in which case the BSC 304 copies the received packets and sends these packets to one or more neighboring BSCs. To do. BSC chaining gives better soft handoff performance. The "anchoring" BSC scheme provides better soft handoff performance. Anchoring BSC304 copies the transmission frame and sends it with the same time stamp to its neighboring BSC. This time stamp information is extremely important for soft handoff operation because the mobile station receives transmission frames from different BSCs.

Multicast Services One type of broadcast service is called the Multi-Cast (MC) service, where a 1MC group includes users who are participants in an MC session. MC content is intended only for MC groups. One MC service is "Group Call (GC)", where the "GC group" includes users who will be participants in the GC, in which case the user's regarding the given MC content. One group is identified. This group of users can also be called an MC group. MC content is intended only for members of the MC group. Each active user in the MC group registers with AN. AN then tracks the locations of each registered user and targets these locations for sending MC messages. In particular, AN determines the cells, sectors and / or geographic regions in which each of the users in the MC group is located, and then sends a message to the PCF associated with these cells, sectors and / or geographic regions. To do.

Contrary to some other types of broadcast services where BC messages are sent without knowledge of the location and behavior of the recipient or subscriber, this MC service provides knowledge of active users, especially the location of each active user. Work with knowledge about. In addition, these users give the AN location information. In one embodiment, active users within a 1MC group specifically register with the AN over IP communication using Internet Group Management Protocol (IGMP) messages. Since the MC service can identify the location of each user and the MC targets these locations for transmission, the MC service utilizes a router between the PCF (s) and PDSN (s). The MC service builds a tree of connections that gives a connection route from the CS to each PCF communicating with the active users in the MC group. This tree is called the MC tree. An example of an MC tree is shown in Figure 6 and is discussed below.

In a traditional IP network or IP system, such as a computer network connected to the Internet, if a user wants to receive MC-type information called MC content, he or she wants to receive the Internet Group Management Protocol (IGMP). Register with the nearest router using Internet Group Management Protocol). The router then begins the process of building the MC tree by registering with the next adjacent router. The CS then sends the MC content in the form of an MCIP packet. This MCIP packet is then routed through the MC tree to the original router. It sends one copy of the data to each network interface with registered members for MC content. A common broadcast medium in computer networks is an Ethernet (registered trademark) hub that connects many users to one and the same stream of information.

The combination of the Internet and an IP network with a wireless communication system introduces some unique problems. One problem is routing information from IP networks over wireless networks. Some of the interconnects are predefined in the wireless system. For example, as mentioned above, the interface between the BSC and the PCF is defined by the A8 / A9 connection. Similarly, the connection from the PCF to the PDSN is defined by the A10 / A11 connection. In one embodiment, an internal MC tree is formed between the PDSN and the PCF, and an external MC tree is formed between the PDSN and the CS. The PCF then forms tunnels specific to the various BSCs that require MC content. This embodiment, discussed below, provides operational efficiency. Another embodiment forms an external MC tree between the PDSN and CS, forming a tunnel from the PDSN to each individual PCF that receives the MC content. This embodiment provides reliable communication.

The MC connection path is generally considered end-to-end, but MC content departs from the source and is transmitted to the end user. The end user can be MS. Alternatively, the MS may be a mobile router that routes MC content to a network. The end user does not transfer MC content. Note that one MC connection path can contain several different types of interconnects. For example, one embodiment may incorporate the aforementioned internal MC tree having an end point in the PCF and an external MC tree having an end point in the PDSN. Similarly, the MC connection path can include a point-to-point tunnel in which each tunnel is formed between one node and another individual node.

According to the exemplary embodiment shown in FIG. 5, the communication system 300 includes a CS 326 that communicates with the PDSN 320, 322 via the IP cloud 324. Note that the CS326 also communicates with other PDSNs not shown. The IP cloud 324 includes a configuration of a router such as a multicast router (as described above) and other routers that allow data transmission to pass through the cloud 324. Transmission through the IP cloud 324 is IP communication. The router in the IP cloud 324 accesses communications such as BC messages and MC messages to target recipients that comply with the Internet Engineering Task Force (IETF) protocol.

Continuing with Figure 5, PDSN 320, 322 communicates with PCF 310, 312 and other PCFs not shown via another IP cloud 314. The IP cloud 314 includes a configuration of a router such as a multicast router and other routers that allow data transmission to pass through the cloud 314. Transmission through the IP cloud 314 is IP communication. The router in IP Cloud 314 accesses communications such as BC and MC messages to target recipients that comply with the Internet Engineering Task Force (IETF) protocol. In addition, PCF310 communicates with BSC304 via yet another IP cloud 308. The IP cloud 314 includes a configuration of a router such as a multicast router and other routers that allow data transmission to pass through the cloud 314. Transmission through the IP cloud 314 is IP communication. The PCF312 also acts as a BSC, communicating with any user (not shown) in System 300. Note that the three BSCs, especially BSC 302, 304 and 306, are shown for clarity. System 300 can include any number of additional BSCs (not shown). Note that alternative embodiments can incorporate alternative configurations in which any connection represented by a number of IP clouds, such as IP clouds 308, 314, 324, can be exchanged with point-to-point connections. A point-to-point connection can be a secure connection formed between a device at one point, such as a PCF, and a device at another point, such as a BSC. Point-to-point connectivity is achieved on top of IP clouds such as IP Cloud 308 using a method called tunneling. The basic idea of tunneling is to take an IP packet, encapsulate it in GRE / IP, and send the resulting packet to the call receiving point. If the notification receiving address in the outer IP header is a unicast IP address, this process is point-to-po Achieve the Int Tunnel. If the call receiving address is a multicast IP address, this process achieves a point-to-multipoint tunnel. Keep in mind that all of this is done within the same IP cloud. For example, in IP Cloud 314, there are several different applicable methods. One method forms a point-to-point tunnel and the second method forms a point-to-multipoint tunnel. This is in contrast to the connection method used within Cloud 324, where GRE tunneling is not used and the original multicast IP packet is sent.

In this exemplary embodiment, the CS326 knows the multicast IP address used within the IP cloud 324 to configure the HSBS channel. The CS uses the MCIP address to send HSBS content information called the payload. Note that the configuration in Figure 8 can be used to broadcast various BC services.

Messages are encapsulated within external IP packets to form a tunnel. Since the encapsulated message is transmitted through the tunnel, the internal IP address, that is, the IP address of the original IP packet, is ignored. This encapsulation modifies the Internet routing selection of the original IP packet. In this exemplary embodiment, the MC tunnel routes BC or MC messages through the MC tree between the PDSN and PCF.

In this exemplary embodiment, PDSN320 and PCF310, 312 are associated with one MC group. In other words, members of the MC group are located within the cells, sectors and / or geographic areas serviced by PCF310, 312. System 300 builds an external MC tree from CS326 to PDSN320 and an internal tree from PDSN320 to PCF310, 312. The PDSN320 builds this external MC tree by sequentially registering with neighboring multicast routers in the IP cloud 324. The external MC tree is built from PDSN320 to CS326 via the IP network. The PDSN320 receives MC messages for members of the MC group via the external MC tree. In other words, MC messages are sent through an external MC tunnel constructed by an external MC tree. Each of PCF310 and 312 builds an internal MC tree to PDSN320 via IP cloud 314. MC messages from PDSN320 are sent on the internal MC tree in the GRE / IP tunnel.

FIG. 6 shows an MC tree 400 with one source 402 and many routers 404-450. Source 402 is the base of MC Tree 400. End users 412, 414, 420, 422, 424, 434, 450 are considered leaves of MC Tree 400. Two main branches are formed via routers 404 and 406. Above the first main branch is another branch via router 410. Above the second main branch are two subsequent branches, one through 430 and the other through 432.

In one embodiment the tree 400 has CS as a source. For broadcast services where broadcast messages occur in CS, source 402 is CS. In an alternative embodiment, the source may be another device within this network. For example, for group call services, the message content can come from another user, in which case the BSC associated with that user is the source of the MC tree. In addition, the network may have a group call manager function that receives messages from certain members and then forwards these messages to members of the group call via the MC tree. In each of these cases, this tree provides a route for delivering the same information content to a large number of users while maintaining bandwidth and avoiding redundant copying and processing of information. As another example, in a many-to-many (M-to-M; Many-to-Many) MC application where any number of hosts send to and receive from the same MC group address, the BSC for that user is in the MC tree. Send MC content as a source of. In addition, there may be an MC application with a network entity that receives messages from some member and forwards those messages to members of the MC group via the MC tree.

FIG. 7 shows a method for processing a BC message according to one embodiment. Process 500 builds an MC tree between at least one BSC and PCF. This tree contains a large number of BSCs. Similarly, additional trees may be built for additional PCFs. The MC tree forms a connection path for sending a BC message to a large number of recipients without forming a point-to-point connection. Process 500 also forms an MC tree between at least one PCF and PDSN. This tree may contain a large number of PCFs and one PDSN, in which case one internal multicast tree according to one embodiment flows through only one PDSN. That is, there is only one base per tree. In addition, Process 500 builds another MC tree between at least one PDSN and CS. This tree can contain a large number of PDSNs.

The broadcasting service of the embodiment shown in FIG. 7 is broadcasting a BC message to a certain transmission area. In the first step 502, process 500 determines the transmission area of the cell, sector, or geographic area for sending the BC message. Transmission area information is used to build the MC tree. In particular, the identification of the transmission area identifies the leaf of the MC tree. The MC tree is built from these leaves to the base. The BSC sends a broadcast indicator to the PCF in step 504. The broadcast indicator is a signal message that warns the PCF that the BSC wants to receive the broadcast. The process then takes step 505 to build a first connection between the BSC in the transmission area and the associated PCF. This connection is a secure tunnel of GRE between each BSC and PCF pair. Then the process is step 506, building an MC tree between the PDSN and the PCF. The transmission area identifies the PCF for BC transmission. Each PCF in the transmission area activates the MC tree by registering with a neighboring multicast router. According to this exemplary embodiment, the process then builds another MC tree from PDSN to CS in step 508. At step 510, CS sends a BC message to PDSN. In this case, the BC message is encapsulated in the MCIP packet. This MCIP packet is addressed to the MCIP address and identifies CS as the source of the packet. The MCIP packet address indicates sending to any of the PDSNs in the MC tree between the PDSN and CS. In step 512, the BC message traverses the MC tree. The BC message is then sent to the BSC in step 513 via a secure tunnel or UC connection. At step 514, the BSC sends this BC message to users in their respective coverage areas.

Note that to adapt to soft handoff in this regard, the receiving BSC is used as an anchor BSC to time stamp the BC message and then forward this BC message to a neighboring BSC. In this way, BC messages are sent from a large number of BSCs to a given user, allowing the user to transition to a better connection without losing transmission. Furthermore, the use of anchor BSCs is efficient because only the PCF sends BC messages to one BSC, but this message can also be given to many other BSCs.

Figure 8 shows process 550 building an MC tree from PCF to PDSN. At step 552, the PCF registers with the next neighboring multicast router. Registration with a multicast router initiates a registration chain, where each member of this chain is registered with the next successor router. Registration with a multicast router further involves identifying the registered PCF as a target for any IP packet addressed to a member of a given MC group and the MCIP address of the MC group. Note that the MC group can be considered an area of interest for BC messages. If the multicast router is registered with the determination symbol 554, the MC tree is completed and this process is terminated. If the multicast router is not registered, that is, it is not part of the MC tree, it will be registered with the next subsequent neighboring multicast router in step 556.

Figure 9A shows the flow of BC messages through a large number of MC trees, as described in Process 500 in Figures 7 and 8. FIG. 9B shows the signal flow of the corresponding information, i.e. broadcast message processing. As shown in Figure 9A, the BC message originates in CS326. The message that occurs is considered a payload. The CS326 encapsulates this payload by applying the MCIP to generate the MCIP packet. This MCIP packet indicates that CS is the source of this packet and the receiver is given as the MCIP address. The MCIP packet is sent to the next router hop above the tree. In other words, MCIP packets traverse outward from the source or root of the tree towards the leaf. Although a single PDSN, especially PDSN320, is shown for clarity, the MC tree can contain any number of PDSNs, each PDSN being traversed by a message addressed to the MCIP address. PDSN320 and other PDSNs in the MC tree also compress MCIP packets, compressed and framed packets (CFP; Apply a framing protocol such as HDLC to form a Compressed Framed Packet). This CFP is then encapsulated by the GRE protocol to form a GRE packet. The resulting GRE packet is further encapsulated according to MCIP into MCCFP, a multicast compressed framed packet. This MCCFP identifies the PDSN320 as the source and the MCIP address as the notification receiver. In the example shown in FIG. 9A, the PDSN320 passes the MCCFP to PCF310, 312, each of which is part of the MC tree. Each of the PCF310 and 312 processes the received MC to form a safe tunnel to a BSC such as the BSC304. The resulting packet is a UCBSC packet that identifies the PCF as the source and the BSCIP address as the receiver. Note that each PCF can form multiple tunnels to individual BSCs. As shown, MCIP addressing is used until the message arrives at the PCF. From PCF to end user This embodiment uses a secure tunnel or UC connection.

Figure 9B shows the corresponding signal flow, where CS first configures the HSBS channel. At time t1, a GRE tunnel is formed between the BSC and the PCF. At time t2, PCF uses IGMP to register with a neighboring multicast router. At time t3, the PCF confirms the GRE tunnel formed by the BSC. Register a multicast router between the PCF and PDSN using the MC Routing Protocol (MRP) at time t4. At time t5, this PDSN is registered with a neighboring multicast router. This process forms the outer part of the MC tree. Each level of the MC tree, namely CS vs. PDSN and PDSN vs. PCF, can be considered as one individual MC tree, or the entire configuration from CS to PCF can be considered as a single tree. At this point, the BSC is configured to receive BC messages from BCCS via MCIP for a given HSBS channel.

FIG. 10 shows an alternative embodiment of Process 700 for sending BC messages. The process begins with determining the broadcast coverage area in step 702. At step 704, a UC connection is formed between the BSC and the PCF. The UC connection can be an A8 / A9 IP connection. Similarly, in step 706, a UC connection is formed between the PCF and the PDSN. In contrast to Process 500 in Figure 10, no MC tree is built between the PDSN and the PCF. Rather, a point-to-point GRE tunnel is formed between each PDSN and PCF pair. The UC connection from PDSN to PCF can be an A10 / A11 IP connection. At step 708, an MC tree is built between the CS and PDSN.

The CS then sends data to the PDSN, which is part of the MC tree, in step 709. This data goes through the MC tree to PDSN in step 10. Then, in step 712, the PDSN processes the received data or BC message and forwards this BC message to the PCF. Keep in mind that when a large number of PCFs are implemented, the PDSN makes many copies of the data for transmission to the large number of PCFs. At step 714, the PCF sends the data to the BSC over the UC connection. Then, in step 716, this data or BC message is sent from the MC group associated BSC to the members of the group.

FIG. 11A shows the flow of BC messages through a large number of MC trees, as described in Process 700 of FIG. FIG. 11B shows the signal flow of the corresponding information, i.e. broadcast message processing. In contrast to process 500 in Figure 7, process 700 builds an MC tree between CS and PDSN, but point-to-point safety between PDSN and PCF and between PCF and individual BSCs. Incorporate a tunnel. Users with point-to-point connections have additional security at the expense of processing and bandwidth considerations.

The BC message originates in CS326, as shown in Figure 11A. The message that occurs is considered a payload. The CS326 encapsulates this payload by applying the MCIP to generate the MCIP packet. This MCIP packet indicates that CS is the source of this packet and the receiver is given as the MCIP address. The MCIP packet is sent to the next contact above the tree. In other words, MCIP packets traverse outward from the source or base of the tree towards the leaf. Although a single PDSN, especially PDSN320, is shown for clarity, the MC tree can contain any number of PDSNs, each identified by an MCIP address. The PDSN320 and any other PDSN in the MC tree compress the MCIP packet and compress it into a framed packet (CFP). Apply a framing protocol such as HDLC to form a Packet). This CFP is then encapsulated by the GRE protocol to form a GRE packet. The resulting GRE packet is further encapsulated according to Unicast (UC) IP into UCCFP, a unicast compressed framed packet. This UCCFP identifies PDSN320 as the source and a specific PCF as the call receiver. In the example shown in FIG. 11A, PDSN320 passes UCCFP to PCF310, 312. Each of PCF310 and 312 processes the received UCCFP in the same way as PDSN320. The resulting packet is a UCBSC packet that identifies the PCF as the source and the BSC as the receiver.

Figure 11B shows the corresponding signal flow, where CS first configures the HSBS channel. At time t1, the BSC forms a GRE tunnel between the BSC and the PCF. At time t2, the PCF forms a GRE tunnel between the PCF and the PDSN. At time t3, the PDSN confirms the GRE tunnel formed by the PCF. At time t4, the PCF confirms the GRE tunnel formed by the BSC. At time t5, the PDSN joins the multicast group using IGMP or MRP. Note that the first process can perform IGMP on the first router. This process forms an MC tree between CS and PDSN. At this point, the BSC is configured to receive BC messages from BCCS via MCIP for a given HSBS channel.

According to one embodiment, the CS uses a local mechanism to configure the HSBS channel for BC service processing. This CS uses the MCIP address to send HSBS content. This HSBS configuration results in CS sending HSBS content to the corresponding MC group. The content is sent in the form of an IP packet with a CS source IP address and a notification receiving IP address as the MCIP address.

The BSC then decides to add an HSBS channel to the given broadcast channel. This broadcast channel should be transmitted over a set of cells / sectors. The mechanism within the BSC that adds the HSBS channel to the broadcast channel is specific to the embodiment. One example of such a mechanism is an interface that enables HSBS channel configuration on the BSC, such as the Operation Administration & Management (OA & M) interface. The BSC uses a local mechanism to configure the HSBS channel with information such as the HSBS-ID of the HSBS channel and the MCIP address corresponding to the HSBS content.

BSC sends an A9-Setup-A8 message to the PCF. In this A9-Setup-A8 message, the BSC sends the A8-Traffic-ID parameter, among others, the GRE key, and the IP address of the BSC entity that terminates the A-8 connection for the HSBS channel. An additional field, IP-Multi-cast Address, is added to the A8-Traffic-ID parameter. This additional field identifies the IP multicast address that CS uses to send HSBS content. New service options for HSBS are used in A9-Setup-A8 messages.

Upon receiving the A9-Setup-A8 message from the BSC, the PCF is informed that the BSC wants to join the IP multicast group. If this PCF is already a member of the desired multicast group, no further action is required to join this multicast group. Otherwise, the PCF sends an IGMP request to the multicast router to join the multicast group. If the IGMP configuration is successful, the PCF sends an A9-Setup-A8 message back to the BSC. Multicast route information propagates through the PDSN all the way to CS from multicast routers that use the multicast routing protocol to upstream routers. This sets up a multicast connection route or multicast tree from CS to PCF. The PCF achieves the binding of the GREA8-Key with the BSC IP address and the IP Multi-cast address in order for the IP multicast packet to pass through the BSC correctly.

There are several multicast routing protocols used for multicast routing in the IP environment. On November 1, 1988, D. Waitzman, C. Partridge, and SE Deering specified the Distance Vector Multi-cast Routing Protocol (DVMRP) in RFC1075. RFC2362 in June 1998 by D. Estrin, D. Farinacci, A. Helmy, D. Thaler, S. Deering, M. Handley, V. Jacobson, C. Liu, P. Sharma and L. Wei. The Protocol Independent Multi-cast-Sparse Mode (PIM-SM) is specified in. In March 1994, J. Moy published "Multi-cast Extensions to OSPF". There is also a Multi-cast Open Shortest Path First (MOSPF) entitled "OSPF", as specified in RFC 1584.

Continuing with Figure 11B, a GRE connection is set up from the BSC to the PCF. Here, a GRE tunnel setup message is sent as shown at time t1 in Figure 11B. In the GRE setup message, the BSC sends a Traffic-ID parameter containing the GRE key and the IP address of the BSC entity that terminates the connection for the HSBS channel. The Traffic-ID parameter can contain a variety of other information. The IP-Multi-cast Address can include the IPMC address used by the CS to send HSBS content.

During operation, CS sends HSBS content, such as BC messages, to the MCIP address. This MCIP address is used in the call receiving address field in the IP packet. The multicast router routes the packet to the member PDSN. Note that multicast group membership is established earlier using IGMP and the MC routing protocol. After header compression (if this is done), the PDSN places each packet within an HDLC frame. HDLC frames are encapsulated within GRE / IP packets. The PDSN sets the Key field of the GRE packet to the notification receiving MCIP address of the encapsulated IP packet. A 20-byte IP packet header having a source address field of the PDSNIP address and a notification receiving address field of the same MCIP address as the encapsulated packet is added to the GRE packet. The PDSN sends the encapsulated HDLC frame to the member multicast router. All multicast member PCFs receive MC packets. The need for sequencing is due to header compression within the PDSN. The GRE contains a sequence number that identifies the packet. The GRE sequence number guarantees the sequential delivery of packets.

Many BSCs are used to broadcast the same HSBS channel that covers a geographic area. In this case, the HSBS channel is tied to a particular frequency. To facilitate autonomous soft handoff, basic broadcast service channels, or F-BSCH transmissions, are synchronized in one geographic area. This takes into account the coupling of broadcast packets at the mobile station. According to one embodiment, the MC tree contains a leaf called an "anchor BSC" that copies broadcast content to a secondary BSC. This anchor BSC copies an HDLC frame and sends it to any secondary BSC on a particular interface, in which case transmission to the secondary BSC has a constrained delay.

FIG. 12 shows how to process an MC message sent to an MC group. This process is for group call services, and the broadcast message may originate from one user in the system. Group calls allow one user to perform point-to-multipoint transmission. One user in a group sends one message to many intended recipients. Process 600 begins at step 602, where CS determines the start time for the MC message. In step 604, the MC group subscriber registers with the BSC. In step 605 BSC sends a setup message to the PCF. This setup message initiates the formation of a GRE tunnel between the BSC and the PCF, notifying that the BSC is part of the group call. This process is step 606, building an MC tree between the PDSN and the PCF. Then the process is step 608, building an internal MC tree from PDSN to CS. Once these MC trees are built, the source sends an MC message addressed to the MCIP address in step 610. At step 612, this message proceeds through these trees. At step 614, the PCF sends an MC message to the BSC over the UC connection. Then in step 616 the BSC forwards this MC message to group members within the corresponding geographic area.

1 Keep in mind that group members move within this communication system with respect to MC messages sent to the MC group. When a group member moves to a location that is not registered in the MC tree or is not part of the MC message transmission, the group member registers with the BSC in that new location. During a group call, group members will be monitoring the frequency assigned to the BC channel used for the group call. By registering with a new BSC, its group members give the system a frequency of BC. The system can then call the group members of the incoming call. Once this group member registers with the new BSC, the system creates a new MC tree containing the new BSC.

FIG. 13 shows in a flow diagram a method of processing a broadcast message or a group call in a system that supports a broadcast message having a broadcast channel and a group call message. Process 520 is similar to process 500 in FIG. 7, where the BSC (or other element involved in the wireless transmission of the message) identifies the BC trigger event. This BC trigger event can be a request from one or more mobile stations or other radios supported by the BSC. For example, in the system 200 shown in FIG. 2, the BSC may receive a request for a BC message from one or more of mobile stations 206. Other triggers may include requests from other BSCs for BC services. The time when the BSC starts BC transmission at a predetermined time may give a trigger. The BC is sent to the predetermined BSC only when the predetermined BSC recognizes the BC trigger and requests a BC message accordingly.

Continuing with Figure 13, process 520 begins with step 502, where the system determines the BC range. The BSC then recognizes the BSC trigger in step 503 and processing continues from step 504 as described for process 500 in FIG.

As described above, the BC transmission is given to the predetermined BSC only when the predetermined BSC recognizes the trigger and requests the BC accordingly. The system then sets up a connection route from the content server to the request BSC. FIG. 14 shows the process of setting and closing the BC transmission line. Dynamic transmission of BC messages is also called "intermittent broadcasting", and this intermittent broadcasting is performed by the process of setting and closing the BC transmission line. As shown in FIG. 14, process 800 is started when the BSC or other radio interface transmitter recognizes the BC trigger. This trigger may be a BC service request from a mobile station or other radio device, or it may be based on a time schedule or other predictable event. For example, in one embodiment, a predetermined BC message, such as a stock exchange update, may be sent at the end of the stock exchange each afternoon. In an alternative embodiment, breaking news is broadcast in real time about the occurrence of the incident. In step 804, the BC transmission line is set up through the network. The connection route can be set as described above. The content server then supplies the BC message in step 806. Upon recognizing the end trigger with the determination symbol 808, the process closes the BC transmission line to the given BSC. The end trigger event can also be the expiration of a time interval. Alternatively, the termination trigger may be that there is no request from a mobile station that previously received BC service.

In one embodiment, a multicast application that a single host sends to more than one recipient is called One-to-Many or 1-to-M. An example of this type of multicast application is also known as a group call. One embodiment of the group call is processed by the system 1000 shown in FIGS. 15A, 15B. At the first time, System 1000 is shown in Figure 15A where many mobile stations 1004 are requesting group call service from BSC1002. In this case, the BSC1002 determines that the number of users who desire this service is less than a predetermined threshold, and if so, the BSC1002 sends to each of the mobile stations 1004 on dedicated channel 1 and another dedicated. Send a group call message to mobile station 1006 on channel 2. These dedicated channels can also be identified by different frequencies or code separated by CDMA systems or other spread spectrum type systems.

At the second time shown in Figure 15B, the number of mobile stations requesting the group call service exceeds a predetermined threshold, and therefore the BSC1002 sends a group call message over a predetermined BC channel. Decide to do. Each of the mobile stations 1004, 1006, 1008 is notified of the transmission channel prior to transmitting the group call message.

Figure 16 shows how to handle a group call 900. Group call is initiated at step 902. The BSC determines with the determination symbol 904 whether the number of active users, i.e. the number of mobile stations or other radios wishing to participate in the group call, is greater than a predetermined threshold. Thresholds can be statically determined and defined for a given system, configuration, or wireless transmitter. Alternatively, the threshold can be dynamically adjusted based on the processing of group calls and the operation of the system. If the number of active users exceeds the threshold, processing continues to step 906, instructing each mobile station that a group call will be transmitted on a given BC channel.

Continuing with Figure 16, in step 908 the BSC sends a group call over the BC channel. The process returns to the determination symbol 904. If the number of active users is not greater than the threshold, the process continues to step 910, where the BSC makes a copy of the group call message for each active user. At step 912, these copies are sent to each active user on a unique dedicated channel. As mentioned above, these dedicated channels may be defined by separate carrier frequencies or may be code division channels.

The group call shown in FIG. 16 is thus made on the unicast channel for a small number of users and transmitted on the multicast channel as the number of users increases. An alternative embodiment may implement another criterion to determine whether to use a unicast channel or a multicast channel based on loading, channel quality and / or amount of data to be transmitted, etc. .. Methods such as those in FIG. 16 maintain transmission resources, including but not limited to, by using separate dedicated channels rather than using broadcast channels. In this case, the decision to use the broadcast channel or the individual channel is determined by the number and distribution of recipients.

In an alternative embodiment, the method described above can be applied to an alternative BC service, in which point-to-multipoint transmission is used. The use of MC trees formed by leaves or endpoints registered with subsequent routers provides a convenient and dynamic way to avoid redundancy in communication systems. In addition, the use of MC trees provides enhanced scalability that reduces the amount of mission-critical facilities required to expand the network. Regarding the operation of group calls, it should be noted that the system can configure the network to the transmitting node, that is, to the wireless interface transmitter such as BSC, even if the wireless interface uses a dedicated channel. In other words, the system applies the multicast tree as described above to the network side and applies the unicast connection route to the participants of the call. In this way the BSC receives only one copy from the network.

Those skilled in the art will appreciate that information and signals can be represented using any of a variety of different techniques and techniques. For example, data, instructions, commands, information, signals, bits, symbols and chips that may be referenced through the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof. Can be represented by.

Those skilled in the art will further appreciate the various exemplary logical blocks, modules, circuits, and algorithmic steps described in connection with the embodiments disclosed herein as electronic hardware, computer software, or a combination thereof. You will admit that it is feasible. To articulate this interchangeability between hardware and software, the various exemplary components, blocks, modules, circuits, and steps are outlined above in terms of their functionality. I've explained. Whether such a function is realized as hardware or software depends on the specific application and design constraints imposed on the entire system. Those skilled in the art may realize the above functions in various ways for each particular application, but decisions of such realization should not be construed as causing a deviation from the scope of the invention.

The various exemplary logic blocks, modules, and circuits described in connection with the embodiments disclosed herein include general purpose processors, digital signal processors (DSPs), and application specific integrated circuits (ASICs). Specific Integrated Circuit (FPGA), Field Programmable Gate Array) or other programmable logic elements, individual gate or transistor logic, individual hardware components, or any combination of these designed to perform the functions described herein can be feasible or feasible. The general purpose processor may be a microprocessor, but as an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. Processors can also be implemented as a combination of computing units, such as a combination of one DSP and one microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors linked to a DSP core, or any other such configuration. Is.

The steps of the methods or algorithms described in connection with the embodiments disclosed herein can be embodied directly in hardware, in software modules executed by a processor, or as a combination of the two. The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other storage medium known in the art. .. An exemplary storage medium is connected to the processor so that the processor can read information from the storage medium and write information to the storage medium. As an alternative, the storage medium can also be integrated into the processor. The processor and storage medium can be resident in the ASIC. This ASIC can be resident in the user terminal. As an alternative, the processor and storage medium can reside as separate components within the user terminal.

The above description of the disclosed embodiments is provided because those skilled in the art will be able to practice or use the present invention. Various modifications to these embodiments will be immediately apparent to those skilled in the art, and the general principles set forth herein are applicable to other embodiments without departing from the spirit or scope of the invention. Thus, the invention is not intended to be limited to the embodiments presented herein, but is subject to the broadest scope that fits the principles and novel features disclosed herein.

<figref num="1">It is a figure of the spectrum diffusion communication system which supports a large number of users.</figref><figref num="2">It is a block diagram of the communication system which supports broadcast transmission.</figref><figref num="3">It is a model of the protocol stack corresponding to the broadcasting service option in the wireless communication system.</figref><figref num="4">It is a flow chart of a message flow about a broadcasting service in a wireless communication system topology.</figref><figref num="5">It is a functional diagram of the wireless communication system which supports the broadcast transmission by the multicast Internet Protocol transmission of the broadcast content.</figref><figref num="6">It is an architecture diagram of a multicast tree structure applicable to a communication system.</figref><figref num="7">It is a flow chart of the broadcasting process in the wireless communication system which incorporated the multicast Internet Protocol transmission.</figref><figref num="8">It is a flow chart of the process of constructing a multicast tree in a communication system.</figref><figref num="9A">It is a flow chart of the multicast processing of a broadcast message in a wireless communication system.</figref><figref num="9B">It is a signal flow diagram which sets a data connection path in a wireless communication system using a multicast Internet protocol.</figref><figref num="10">It is a flow chart of the multicast processing of a broadcast message in a wireless communication system.</figref><figref num="11A">It is a flow chart of the multicast processing of a broadcast message in a wireless communication system.</figref><figref num="11B">It is a signal flow chart of broadcasting processing in a wireless communication system using a multicast Internet protocol.</figref><figref num="12">It is a flow chart of a message flow about a group call service in a wireless communication system topology.</figref><figref num="13">It is a flow chart of the broadcasting process in the wireless communication system which incorporated the multicast Internet Protocol transmission.</figref><figref num="14">It is a flow chart which gives provisional broadcasting processing in a wireless communication system.</figref><figref num="15A">It is a figure which illustrates the group call operation in a wireless communication system.</figref><figref num="15B">It is a figure which illustrates the group call operation in a wireless communication system.</figref><figref num="16">It is a flow chart which illustrates the group call operation in a wireless communication system.</figref>