Methods and apparatus for retransmission based access priority in a communications system

Methods and apparatus for retransmission based access priority in a communications system

1 is a block diagram of a UMTS access network;

2 is a diagram of a protocol stack associated with UMTS;

3 is a block diagram of an incoherent RACH receiver used in UMTS;

4A and 4B are diagrams for explaining structures of an access slot and a random access burst used in UMTS RACH;

5 is a flowchart of a method for controlling access priority in a remote terminal according to a first embodiment of the present invention;

6 is a flowchart of a method for controlling access priority in a remote terminal according to a second embodiment of the present invention;

7 is a flowchart of a method for controlling access priority in a remote terminal according to a third embodiment of the present invention;

8 is a flowchart of a method for controlling access priority in a remote terminal according to a fourth embodiment of the present invention;

9 is a flowchart of a method for controlling access priority in a remote terminal according to a fifth embodiment of the present invention;

Fig. 10 is a flowchart of a method for controlling access priority in a remote terminal according to a sixth embodiment of the present invention;

11 is a flowchart of a method for controlling access priority in a base station according to the present invention;

12A is a flow chart illustrating overall ODMAFQ protocol operation observed by a remote host;

12B is a flowchart illustrating overall ODMAFQ protocol operation observed by a base station;

13A is a flowchart illustrating an embodiment of a method for ODMAFQ access control;

13B is a flow diagram illustrating another embodiment of a method for ODMAFQ access control.

14A to 14C are flowcharts illustrating three ODMAFQ contention resolution methods.

<Explanation of symbols for main parts of the drawing>

2, 4: remote terminal 6: base station

10, 12, 14: Block 20: Database

24 : Core Network 30 : Receiver

32 : Mixer 34 : Filter

36 : sampling unit 38 : despreader

42 : Integrator 46 : Timing Detector

50 : time shifting unit 56 : searcher

<background-art><p>Cross-reference of related patent applications</p><p>The present invention is "Methods for Access Control in a Multiple Access System for Communications Networks" U.S. Serial No., filed on May 22, 1998. It is a continuation of some of the patent applications identified as 09/084,072. In addition, the present application relates to "Methods and Apparatus for Random Chip Delay Access Priority on a Communications System" and "Methods and Apparatus for Retransmission Based Access Priority in a Communications System" pertaining to US patent applications.</p><p>Field of the Invention</p><p>The present invention relates to a method and apparatus for providing access priority control in a communication system, and more particularly, to a method and apparatus for providing access priority control in a medium access control protocol of a universal mobile telecommunications system will be.</p><p>BACKGROUND OF THE INVENTION</p><p>In recent years, major efforts have been made to integrate multimedia functions into mobile communications. The International Telecommunications Union (ITU) and other organizations intend to develop standards and recommendations to ensure that future mobile communications can support multimedia applications with at least the same quality as existing fixed networks. In particular, a number of overall research projectors have been sponsored to develop these next-generation (third-generation) mobile systems. Research and Development of Advanced Communication Technologies in Europe, RACE-1 and RACE-2, and Advanced Communication Technologies and Services (ACTS) are examples of such efforts in Europe. It is known that Internet access, video/image transfer, and high bit rate functions are required to provide terminal users with essential service quality for multimedia communication. Given these requirements, a lowered functional target for a 3rd generation system is defined as 364 kilobits per second (kb/s) for full coverage area and 2 megabits per second (Mb/s) for local area coverage. .</p><p>General Mobile Telecommunications System (UMTS) is a new radio access network based on 5 Megahertz wideband code division multiple access (W-CDMA) and optimized to support third-generation services including multimedia-enabled mobile communications. Since the main design objective of UMTS is to provide a broadband multimedia communication system that integrates infrastructure for mobile and fixed communications, and, inter alia, to provide a range of services such as that provided by fixed and wireless communications networks, UMTS is not only a circuit-switch Packet-switch services, various mixed media traffic types, and demand broadband must be provided. However, providing multimedia support requires flexibility, i.e. different bit rates and E_b/N_o It means the need to support services as a requirement and to be able to multiplex these services in a multi-service environment. UMTS is designed to support this demand.</p><p>1, an exemplary block diagram of a UMTS access network is shown. In particular, a number of remote terminals 2 , 4 (eg mobile terminals) communicate with a base station (NODE-B) 6 via a W-CDMA radio link 8 . The remote terminal may be a wireless telephone 2 or a portable personal computer 4 with an internal or external modem. In the UMTS standard, the base station is referred to as NODE-B. These base stations provide radio resource management functions and communicate with a network component called a Radio Network Controller (RNC). Since UMTS is a W-CDMA system, soft handoff is supported. In the case of soft handoff, there are two base stations 6 serving one remote terminal. So, the remote terminal forwards a frame to these two base stations. When both base stations receive frames from remote terminals, they forward them to a Frame Selector Unit (FSU). The FSU decides, for frame quality, which frame is better to be delivered to the core network. In UMTS, the FSU may be physically integrated with the RNC, in FIG. 1 the RNC and the FSU are shown as block 10, but are also functionally separated as block 12 (FSU) and block 14 (RNC). . Other elements within the UMTS network implement conventional functions such as an xLR database 20 and an interworking function (IWF) unit that provides home and visited location information. The Universal Mobile Switching Center (UMSC) 16 operates as a mobile switching center for the base station 6 in the UMTS. Sub-network 18 is a wireless service provider network, and CN1 to CNn are core networks 24 to which remote terminals are ultimately connected.</p><p>Referring to FIG. 2 , a diagram of a typical protocol stack in UMTS is shown. In UMTS, Layer 1 (L1) is a Physical Layer (PHY) that provides information transfer services to the MAC (Media Access Control) layer and higher layers. The physical layer transport service is described by how and what characteristic data is transported over the transport channel of the air interface. Layer 2 (L2) is composed of sub-layers including MAC, Link Access Control (LAC), and RLC and Radio Link Control (RLC'). In UMTS, the execution function of RLC is separated and two RLC protocols (RLC and RLC') are specified. The RLC and MAC layers provide real-time and non-real-time services. The MAC layer controls but does not perform multiplexing of streams derived from other services. That is, the MAC layer allows a common physical communication channel (eg, a broadcast channel) to be shared by multiple remote terminals through a logical channel. IP (Internet Protocol) is the network layer.</p><p>"Uu" refers to the UMTS-specific interface between the remote terminal and the base station, and "Iub" refers to the UMTS-specific interface between the base station and the RNC/FSU. Layer 2 of the radio access network (i.e., the left side of NODE-B in the protocol stack) is divided into RLC and MAC layers, and Layer 2 of the core network (i.e. the right side of NODE-B in the protocol stack) transports the network layer frames. It is further related to the technology used to do this, for example, Asynchronous Transfer Mode (ATM) or Frame Relay. Although IP is shown as a transport protocol, UMTS is not so limited. That is, UMTS may be provided for other transport protocols. For more details on the protocol layer, see Dahlman, "UMTS/IMT-2000 Based on Wideband CDMA", IEEE Correspondence Journal, pp. 70-80 (September 1998) and ETSI SMG2/UMTS L2 &amp; L3 Expert Group, "MS-UTRAN Air Interface Protocol Design; Stage 2 (MS-UTRAN Radio Interface Protocol Architecture; Stage 2)", available at Tdoc SMG2 UMTS-L23 172/98 (September 1998).</p><p>In UMTS, four types of application traffic need to be processed. (i) applications that are sensitive to delay and loss, for example, interactive video; (ii) applications that are sensitive to loss but can tolerate reasonable delays, such as, for example, interactive data; (iii) applications that are sensitive to delay but tolerate moderate losses, eg, voice; and (iv) applications that tolerate both delay and loss, such as, for example, file transfers.</p><p>In order to provide different Quality of Service (QoS) to all different applications, UMTS must be properly designed. In UMTS system design, several important items need to be considered, for example, how to satisfy QoS without wasting network resources and how to operate the system in a stable zone when all traffic types are burst simultaneously. .</p><p>Also, in UMTS, several components are required to support changing QoS. Service parameters to allow different applications to define different QoS requirements, for example Guaranteed Service and Controlled Load Service parameters defined by the Internet Engineering Task Force (IETF). needs to be defined. A user may request bandwidth resources in a burst mode or a connected mode. In addition, UMTS requires an admission control component to determine whether a user's request has been accepted. The granting of new requests must be done so that the QoS requirements of each request are not violated (unless it is a best-effort request), even when all granted requests are peaking at the same time. Also, once the user's request is granted, the UMTS network must have characteristics implemented to convey these service guarantees, such as delay requirements, packet loss requirements, for example. Packet marking for the user's traffic that does not match the scheduling algorithm in the network node is part of the characteristics that can be supported by the router to provide a differentiated service.</p><p>In order to provide terminal-to-terminal QoS in UMTS, specific characteristics need to be provided in the MAC layer to guarantee different QoS. One possible way to provide different QoS is to provide a priority device. Priority devices may implement access priorities, service priorities, or buffer management structures. There are various kinds of service priority devices, such as fixed priority and dynamic priority. Fixed priority devices include, for example, strict priority and weighted league systems. Dynamic priorities include, for example, fair share queuing, a fair share queue of its own clock, and worst case fair share queuing rules.</p><p>For access priority, several known channel access protocols are currently used in wireless data systems such as Slotted Aloha, PRMA, and the like. Conventional Slotted Aloha is a relatively simple protocol, but since it does not attempt to avoid or resolve conflicts between data users, its theoretical capacity is only on the order of 0.37.</p><p>Predestination-based protocols attempt to avoid and resolve conflicts by dynamically scheduling the channel bandwidth through which the user will forward packets. Typically, in this protocol, channels are divided into slots that are grouped into frames of N slots. The slot may also be further divided into k minislots. In general, the A in slot₁is used for predestination, the rest A - A₁ A slot is a data slot. The user who needs to forward the packet is B = A₁ * Delivers a scheduled request packet to one of the k minislots. If the reservation request packet is successful, the user is assigned a certain number of data slots until either the user or the base station releases the reservation. If the reservation request packet is not successful, the user uses the conflict resolution method of retransmitting the reservation request until it is successfully transmitted.</p><p>Access priority control is particularly important for one of the logical channels associated with the media access control (MAC) protocol of UMTS, that is, a random access channel (RACH). RACH is an uplink common transport channel used to carry control information and short user packets from remote terminals. 3, a block diagram of an exemplary hardware implementation of an incoherent RACH detection algorithm used in a UMTS base station (NODE-B in FIG. 1) is shown. The RACH receiver 30 may provide the following functions: detection, demodulation and decoding, and acknowledgment. The detection objective is to determine whether a RACH burst, which will be described later, is being conveyed by a remote terminal and to resolve the strongest multipath component of the incoming burst. The receiver 30 also identifies the remote terminal identifier and the requested service, and demodulates and decodes the message contained in the corresponding RACH. After decoding the remote terminal RACH transmission, the receiver generates an acknowledgment signal that the base station transmits to the remote terminal over a Forward Access Channel (FACH).</p><p>The RACH receiver 30 preferably implements the above function according to the following structure. The RACH transmit burst is received by a mixer (32), demodulated, and filtered in a filter (34). The signal is then sampled in a sampling unit 36 . A despreader 38 decodes the signal according to a spreading sequence, in this case a 512 Gold code. The decoded signal is buffered (buffer 40) and passed to the time shifting unit 50 . The output of despreader 38 is also provided to integrator 42 . The output of integrator 42 is mixed (mixer 44 ) and provided to timing detector 46 and threshold detector 48 . The output of the threshold detector 48 indicates whether a valid signal has been received from the remote terminal. This result is provided to the time shifting unit 50 . If it is a valid signal (eg, the predetermined threshold), the decoded signal is then down sampled by unit 52 . Depending on the preamble to be described later, the signal is passed through the 16 tap filter unit 54 to the preamble signature searcher 56 . The output of the searcher 56 provides the base station with the identifier of the remote terminal and information about the service requested by the remote terminal.</p><p>It is known that the physical RACH is designed based on the Slotted ALOHA approach. The remote terminal has 8 well-defined time offsets (access slots #1, ..., access slots # In i, ..., access slot #8, the random access burst 100 may be transmitted. As shown in Fig. 4b, the random access burst is composed of two parts, namely a 1 ms-long prefix 102 and a 10 ms-long message part 104, with an idle time of 0.25 ms between the prefix and the message part. There is (idle time) 106 . There are a total of 16 different prefix signatures based on a set of length 16 Orthogonal Gold codes (512 Gold codes). Information on available signatures and time offsets is broadcast on the BCCH. Based on this structure, if the receiver has 128 parallel processing units (16 prefix signatures multiplied by 8 timeslots), 128 random access attempts can be detected simultaneously. In other words, you will have the same 128 random access channels for the maximum configured base station of the current cell.</p><p>Accordingly, there is a need for a method and apparatus for providing access priority in UMTS that addresses the unique requirements associated with such a broadband multimedia communication system. In particular, there is a need for a method and apparatus for providing access priority for UMTS RACH.</p></background-art><tech><p>The present invention provides a method and apparatus for providing access priority in a MAC protocol of a communication system, for example for UMTS RACH. In particular, the present invention relates to (i) random chip delay access priority (RCDAP); (ii) access priority based on random backoff (RBBAP); (iii) Variable Logical Channel Based Access Priority (VLCAP); (iv) UMTS-specific change versus variable logical channel based access priority structure (VLCAP'); (v) Probability-Based Access Priority (PBAP); and (vi) retransmission basis access priority (REBAP).</p><p>In one aspect of the present invention, an RCDAP method and apparatus are provided. In RCDAP, each priority class is advantageously assigned a different chip delay among chip delay distributions before delegating an access request to the base station. Preferably, the higher priority class is given a smaller average random chip delay, so that the access request is more likely to be captured compared to that given by the lower priority class.</p><p>In another aspect of the present invention, an RBBAP method and apparatus are provided. In RBBAP, each priority class is advantageously assigned a different backoff delay. Preferably, requests associated with a higher access priority will have a smaller average backoff delay. Whenever there is a collision or an access request is not successfully received at the base station for some other reason, the remote terminal chooses a random delay distributed between predetermined ranges depending on class (i).</p><p>In another aspect of the present invention, a VLCAP method and apparatus are provided. In VLCAP, each subscriber is given an access priority class (i). Preferably, the subscriber with the highest priority can access all logical access channels on which the base station is configured, and the subscribers with the lowest priority have logical access, e.g. one prefix signature with 8 time offsets. Only a small subset of channels are allowed to be accessed. The fundamental concept of this approach is that the greater the number of logical access channels a remote terminal must select, the more likely it is to find a channel through which the request will be transmitted successfully.</p><p>In another aspect of the present invention, a UMTS-specific variation of the VLCAP method and apparatus is provided. The VLCAP' approach specifically takes into account the specific UMTS access channel structure. That is, even if there are t time slots for each prefix signature, there cannot be t parallel processing units at the base station due to limitations on the complexity of processing associated with the base station. For example, each (i^th, (i+4)^th) programmed to acquire time slots, so there can be only 4 receivers. So, according to the VLCAP' approach, requests with lower priority classes are assigned to a larger number of time offsets, thus allowing access requests from higher priority classes to be captured by the receiver first.</p><p>In another aspect of the present invention, a PBAP method and apparatus are provided. In PBAP, each subscriber is given an access priority class (i). Each access priority class (i) has only a certain probability (P_It's) can only transmit access requests with Those with the highest priority always send their access requests whenever they have them.</p><p>In another aspect of the present invention, a REBAP method and apparatus are provided. In REBAP, an access request has an access packet priority (APP) associated with it, whereby an access request that is retransmitted is given a higher priority over the new access request.</p><p>It should be understood that the access priority technique implemented in accordance with the present invention may include a combination of one or more of the above embodiments. For example, RCDAP may be implemented with RBBAP or VLCAP and PBAP and the like.</p><p>These and other objects, features, and advantages of the present invention will become apparent from the following detailed description of the embodiments taken in conjunction with the accompanying drawings.</p></tech>

<p>The present invention will hereinafter be described for access priority control in the MAC layer of UMTS, in particular, access priority control in a random access channel or RACH. However, it should be understood that the teachings of the invention discussed herein are not so limited. That is, the access priority method of the present invention can be applied to other communication systems, so that a remote terminal (eg, mobile or fixed) is randomly selected to ensure access to a communication channel associated with a base station or other communication system access point. will try In addition, it should be understood that the methods described herein for use in a remote terminal or base station are implemented by one or more processors each associated therewith. As used herein, the term "processor" is intended to include processing devices, including central processing units (CPUs) and associated memory. Accordingly, any software instructions or code associated with practicing the method of the present invention may be stored in the associated memory and retrieved and executed by the appropriate CPU when ready to be used. In addition, the term "remote terminal" refers to a device capable of communicating with a base station. For example, the remote terminal may be mobile (eg, a wireless telephone or portable personal computer with a wireless modem) or stationary (eg, a stationary personal computer with a wireless modem). Also, "base station" and "noce_b" are used interchangeably herein.</p><p>As described above, the present invention is a US application filed on May 22, 1998 under the name "Method for Access Control in a Multiple Access System for Communication Networks". Patent application serial No. 09/084,072, in which "on-demand multiple access fair queuing" Alternatively, another MAC protocol called ODMAFQ is described. A section entitled "ODMAFQ MAC Protocol Operation" describing the relevant MAC functions follows the detailed description of the present invention.</p><p>As described above with reference again to FIG. 1 , the remote terminals 2 , 4 are connected to the UMTS access network via an air interface with the base station 6 . To establish communication, the remote terminal forwards and receives media access control (MAC) frames via the air interface with the base station 6 . In the case of the terminal 4, an internal or external modem is used to provide a wireless connection with the base station. A remote terminal, such as remote terminal 2, typically has its own internal modem. Nevertheless, packets are typically generated or received at the remote terminal on a burst random basis. Packets are buffered at the remote terminal until transmitted uplink to the base station. As is known, the base station 6 provides a large radio coverage area and multiplexes remote terminal traffic from each coverage area to the mobile switching center of the system, e.g., UMSC 16 in FIG. The base station also broadcasts (down-link) packets destined for one or more remote terminals in the cell.</p><p>The UMTS multiple access architecture is a time-slotted system (ie, the Slotted ALOHA approach) in which a random access channel (RACH) and a packet transport channel are formed on a slot-by-slot basis. The time slot duration in each channel is chosen based on the particular system being implemented. Typically, a remote terminal with a packet to be forwarded sends an access request to the base station via the RACH. Due to the potentially large number of remote terminals compared to the relatively small number of access channels that the base station is configured to support, the access priority structure is necessary to ensure the orderly and temporal processing of network traffic. That is, given the fact that many remote terminals randomly want to use a single communication channel (i.e., require a channel bandwidth for forwarding packets), the method of prioritizing access requests is a relatively high-demand remote method. It should be implemented in the network to allow the terminal to access the channel bandwidth associated with the base station across remote terminals that require relatively little. So, for example, if two remote terminals have packet data to be transmitted to the base station, the access request of the remote terminal with a higher access rate needs to be received and accommodated more easily than the other remote terminals. However, it should be understood that the priority class of the remote terminal is dynamic. That is, it depends on the content and/or characteristics of the packet to be transmitted and the characteristics of the remote terminal. For example, if the packet represents data that is delay-sensitive (eg interactive video, voice) or has characteristics that guarantee immediate transmission (eg emergency), the remote terminal will give the context-sensitive priority. , that is, in this case, a priority class having a higher priority is selected. Also, depending on the service level to which the remote terminal is subscribed (eg, express or regular), different access priorities are assigned.</p><p>Referring to FIG. 11 , a flowchart of a method 1100 for controlling access priority in a base station according to the present invention is shown. In UMTS, a base station (e.g., base station 6) broadcasts an access priority system parameter in a beacon or pilot signal to a remote terminal (RT) within its coverage area (step 112). As specifically described according to the method of access priority executed in the remote terminal, the access priority system parameter includes the parameter used by the remote terminal in processing the base station access request. That is, the base station transmits parameters for each predetermined priority class that the remote terminal receives and stores for use during the access request. At step 1104, the base station (via its associated processor) determines whether an access request has been received from a remote terminal. Otherwise, the base station waits to be received. When the access request is received from the remote terminal, the base station forwards an acknowledgment message to the remote terminal to indicate that the request has been successfully received (step 1106). This acknowledgment signal is transmitted on the Forward Access Channel (FACH) between the base station and the remote terminal. The base station then prepares to receive packet data from the remote terminal granted access according to the packet data reception procedure used in UMTS (step 1108).</p><p>Referring now to FIG. 5, there is shown a flow diagram of a method 500 for controlling access priority at a remote terminal in accordance with a first embodiment of the present invention. It should be understood that this method is performed at a remote terminal (eg remote terminal 2, 4) that has generated or received a packet that is uplinked to a UMTS base station (eg, base station 6). The embodiment shown in FIG. 5 is hereinafter referred to as Random Chip Delay Access Priority (RCDAP). In general, in the RCDAP approach, each priority class is advantageously assigned a different average random chip delay before submitting an access request to the base station. Each chip is known to be a specific period of time, and as such, each chip exhibits a specific time delay. So, the time duration of the chip delay is directly related to the number of chips in the delay. Longer delays have more chips than shorter delays. It should be understood that the use of chip delay results from the use of the CDMA air interface (W-CDMA) between the remote terminal and the base station in UMTS. According to one embodiment of the present invention, the higher priority class is given a smaller average random chip delay, so that access requests have smaller time delays, so that those submitted by users with lower priority classes are different from those submitted by users with lower priority classes. are more likely to be caught by comparison.</p><p>5, the remote terminal receives (in memory) and stores (in memory) the following access priority system parameters broadcast by the base station in step 501: the logical existing between the remote terminal and the base station. M, the number of access channels; K, the maximum number of retransmission attempts for each class (i)_It's; (RN_It's, ..., RN_It's') random chip delay for each class (i) distributed between , where RN_It's &lt; RN_i+1, RN_It's' RN_i+1', for example RN₀ &lt; RN₁, RN₀' RN₁'. It is understood that i = 0, 1, ... etc. Thus, the chip delay associated with access priority class 0 (the highest priority) is selected from a distribution of random chip delays that, on average, are smaller than the chip delays in the distribution associated with a lower access priority class, e.g., class 1 . Thus, a remote terminal set to class 0 has a higher priority than a remote terminal set to class 1.</p><p>Accordingly, in step 502, the remote terminal (via its associated processor) determines whether a new access request is required due to receipt of the transmitted packet. If so, in step 504, the remote terminal selects a logical access channel (1, ..., M). Then, the required priority class (eg, due to the nature or content of the data being transmitted) or the priority level assigned to the remote terminal (eg, the user of the remote terminal can provide a specific level of service, such as regular, express, etc.). based on the distribution (RN) in step 506_It's, ..., RN_It's') to select a random chip delay. So, if the priority of the transmission is high, the remote terminal selects from the lowest random chip delay distribution, thereby increasing the likelihood that the request will be successful. If the priority of the transmission is low, the remote terminal selects from the highest random chip delay distribution, thereby reducing the likelihood that the request will be successful compared to a remote terminal requesting access with a higher priority class. Of course, depending on the priority, the remote terminal can choose from a random chip delay distribution in between. The access result is then sent to the selected logical access channel in step 508 according to the selected chip delay.</p><p>Next, in step 510, the terminal determines whether the access request has been successfully received by the base station. This is accomplished by the base station sending an access request acknowledgment message to the terminal (step 1106 in FIG. 11). If the access request is successful, the access priority control method ends (step 512), and the remote terminal may transmit the packet according to the packet forwarding structure used in UMTS.</p><p>However, if the request is not successful, in step 514, the terminal increments a variable called no_tx by one (no_tx ++). The variable no_tx represents the number of times an access request has been sent by the remote terminal (its value is stored in a memory associated with the remote terminal processor). In step 516, no_tx is K_It's(maximum number of retransmission attempts for class I). no_tx is K_It's If greater than, the current access request is canceled (step 518). A higher priority class is given a higher K so that more retransmission attempts are made._It's(i.e. K_It's K_i+1) is specified in If the maximum number of retransmissions has not been reached, a backoff process is performed in step 520 . Assuming that several remote terminals intended to transmit an access request signal at approximately the same time were unsuccessful (for example, the unsuccessful was due to a conflict between requests), it is assumed that each remote terminal attempts to retransmit at approximately the same time. It is to be understood that the backoff procedure is preferably used, as this is not desirable. Therefore, each terminal delays the retransmission by a randomly selected amount of time to reduce the possibility of collision of the retransmitted access request. In another method embodiment, the backoff may be performed in accordance with the process of the present invention described below with respect to FIG. 6 . After backoff, the remote terminal waits for the next available access slot at step 522, then returns to step 504 to repeat the process.</p><p>Referring now to FIG. 6, there is shown a flow diagram of a method 600 for controlling access priority at a remote terminal in accordance with a second embodiment of the present invention. Again, it should be understood that the method is performed at a remote terminal (eg, terminal 2 or 4) that has generated or received a packet to be transmitted uplink to a UMTS base station (eg, base station 6). The embodiment described in FIG. 6 is hereinafter referred to as Random Backoff Based Access Priority (RBBAP). In general, in the RBBAP approach, each priority class is advantageously assigned a different average backoff delay. A request associated with a higher access priority will have a smaller average backoff delay. Whenever there is a conflict or other reason that the access request cannot be successfully received at the base station, the remote terminal depends on class (i) D_It's D_It's', D_It's D_i+1, D_It's' D_i+1'in range (D_It's, ..., D_It's'), where class (i) has a higher priority than class (i+1).</p><p>In the access priority embodiment of Figure 6, the remote terminal receives (in memory) and stores (in memory) the following access priority system parameters broadcast by the base station in step 601: the logical existing between the remote terminal and the base station. M, the number of access channels; K, the maximum number of retransmission attempts for each class (i)_It's; D_It's D_It's', D_It's D_i+1, D_It's' D_i+1'in range (D_It's, ..., D_It's'), where class (i) has a higher priority than class (i+1). Thus, the backoff delay associated with a higher access priority class is selected from a distribution of random backoff delays that, on average, are lower than the backoff delays in the distribution associated with the lower access priority access. For example, a remote terminal set to class 0 has a higher priority than a remote terminal set to class 1.</p><p>Accordingly, in step 602, the remote terminal (via its associated processor) determines whether a new access request is required due to receipt of the transmitted packet. If so, in step 604, the remote terminal selects a logical access channel 1, ..., M. The access request is then sent to the selected logical access channel in step 606 . In the next step 608, the terminal determines whether the access request has been successfully received by the base station. Again, this is accomplished by the base station sending an access request acknowledgment message to the terminal (step 1106 in Fig. 11). If the access request is successful, the access priority control method ends (step 610), and the remote terminal may forward the packet according to the packet forwarding structure used in UMTS.</p><p>However, if the request is not successful, in step 612, the terminal increments the variable no_tx by one. In step 614, no_tx is K_It'scompared to no_tx is K_It's If greater than, the current access request is canceled (step 616). If the maximum number of retransmissions has not been reached, a backoff process is performed in step 618 . In step 618, the terminals are distributed (D) based on the required priority rating or the priority rating assigned to the remote terminal._It's, ..., D_It's') to select a random backoff delay. So, if the priority of the transmission is high, the remote terminal selects from the lowest random backoff delay distribution, increasing the likelihood that the request will be successful. That is, the backoff delay is relatively short such that retransmissions are relatively faster than lower classes. If the priority of the transmission is low, the remote terminal selects from the highest random backoff delay distribution, reducing the likelihood that the request will be successful compared to a remote terminal requesting access with a higher priority class. Of course, depending on the priority, the remote terminal can choose from a random backoff delay distribution between them. After the backoff, the remote terminal waits for the next available access slot at step 620 and then returns to step 604 to repeat the process.</p><p>Referring now to FIG. 7, there is shown a flow diagram of a method 700 for controlling access priority at a remote terminal in accordance with a third embodiment of the present invention. Again, this method is understood to be practiced at a remote terminal (eg, terminal 2 or 4) that has generated or received a packet that is transmitted uplink to a UMTS base station (eg, base station 6). The embodiment shown in FIG. 7 is hereinafter referred to as Variable Logical Channel-based Access Priority (VLCAP). In general, in the VLCAP approach, each subscriber is given an access priority class (i). The subscriber with the highest priority (class 0) can access all logical access channels (e.g. 16x8) for which the base station is configured, and the subscriber with the lowest priority can access a small subset of logical access channels, e.g. For example, only one prefix signature with an 8 time offset is allowed to be accessed. The underlying principle under this approach is that the greater the number of logical access channels a remote terminal has to select, the more likely it is to find a channel through which an access request will be successfully transmitted.</p><p>In the access priority embodiment of Figure 7, the remote terminal receives (in memory) and stores (in memory) the following access priority system parameters broadcast by the base station in step 701: the logical existing between the remote terminal and the base station. M, the number of access channels; N, the maximum number of logical access channels that class (i) can access_It'sas, where N_It's &gt; N_i+1and N₀ = M; K, the maximum number of retransmission attempts for each class (i)_It's.</p><p>Accordingly, in step 702, the remote terminal (via its associated processor) determines whether a new access request is required due to receipt of the transmitted packet. If so, in step 704, the remote terminal selects a logical access channel (1, ..., M). That is, a logical channel is selected from a set of logical channels, and the size of the set depends on the priority class of the request. According to the priority class for which the request is highest, the remote terminal can select from all M logical access channels, and reducing the priority requirement reduces the size of the subset it selects. In another method embodiment, the remote terminal may store and select a random chip delay at this point according to the RCDAP approach of FIG. The access request is then sent to the selected logical access channel in step 706 . In the next step 708, the terminal determines whether the access request has been successfully received by the base station. Again, this may be accomplished by the base station sending an access request acknowledgment message to the terminal (step 1106 in FIG. 11 ). If the access request is successful, the access priority control method ends (step 710), and the remote terminal may transmit the packet according to the packet forwarding structure used in UMTS.</p><p>However, if the request is not successful, in step 712, the terminal increments the variable no_tx by one. In step 714, no_tx is K_It'scompared to no_tx is K_It's If greater than, the current access request is canceled (step 716). If the maximum number of retransmissions has not been reached, a backoff process is performed in step 718 . In another method embodiment, the backoff process is the same as described above in step 618 of FIG. 6 . After the backoff, the remote terminal waits for the next available access slot in step 720 and then returns to step 704 to repeat the process.</p><p>Referring to Fig. 8, there is shown a flow diagram of a method 800 for controlling access priority at a remote terminal according to a fourth embodiment of the present invention. It should be understood that method 800 is a variant of the VLCAP structure of FIG. 7 . That variant is called VLCAP' and specifically takes into account a specific UMTS access channel structure. That is, although there are 8 time offsets for each pre-signature, the base station does not have 8 parallel processing units due to limitations on processing complexity associated with the base station. For example, if each receiver, for example (i^th, (i+4)^th), there are only 4 receivers programmed to capture the time offset. However, it should be understood that the time offsets need not be sequential. That is, the receiver may acquire the first four time offsets received, eg, time offsets 1, 3, 5, and 6. So, according to the VLCAP' approach, requests with lower priority classes are assigned to a higher number of time offsets, allowing access requests from higher priority classes to be captured by the receiver first. That is, if the rank is a high priority rank, it is assigned a low time offset from selecting (eg, 1 to 4), and a low priority rank is assigned a high time offset from selecting (eg, 5 to 4). 8) is specified. Therefore, a higher priority access request is more likely to be received than a lower priority access request.</p><p>8, the remote terminal receives (in memory) and stores (in memory) the following access priority system parameters broadcast by the base station in step 801: P, the maximum number of prefix signatures (eg For example, P 16); T being the number of time offsets (eg, T &lt; 8), and M thereby being the total (PxT) number of logical access channels representing the number of time search functions and processing units included in the base station; and K, the maximum number of retransmission attempts for each class (i)._It's.</p><p>Accordingly, in step 802, the remote terminal determines (via its associated processor) whether a new access request is required due to receipt of a transmitted packet. If so, in step 804, the remote terminal selects a prefix from among (1, ..., P). Then, in step 806, for class (i), the remote terminal_It's &lt; T_i+1, T_It's' ' T_i+1', T₀ = 0, T_max' = 8 people (T_It's, ..., T_It's') to select one time offset from For example, class 0 (the highest priority class) may select from a set of time offsets that range between time offset 0 and time offset 4. In another method embodiment, the remote terminal may store and select a random chip delay at this point according to the RCDAP approach of FIG. The access request is then sent to the selected logical access channel in step 808 .</p><p>In the next step 810, the terminal determines whether the access request has been successfully received by the base station. Again, this is accomplished by the base station sending an access request acknowledgment message to the terminal (step 1106 in Fig. 11). If the access request is successful, the access priority control method ends (step 812), and the remote terminal may transmit the packet according to the packet forwarding structure used in UMTS.</p><p>However, if the request is not successful, in step 814, the terminal increments the variable no_tx by one. In step 816, no_tx is K_It'scompared to no_tx is K_It's If greater than, the current access request is canceled (step 818). If the maximum number of retransmissions has not been reached, a backoff process is performed in step 820 . In another method embodiment, the backoff process is the same as described above in step 618 of FIG. 6 . After the backoff, the remote terminal waits for the next available access slot at step 822 and then returns to step 804 to repeat the process.</p><p>Referring now to FIG. 9, there is shown a flow diagram of a method 900 for controlling access priority at a remote terminal in accordance with a fifth embodiment of the present invention. Again, it should be understood that the method is performed at a remote terminal (eg, terminal 2 or 4) that has generated or received a packet to be uplinked to a UMTS base station (eg, base station 6). The embodiment shown in FIG. 9 is hereinafter referred to as Probability Based Access Priority (PBAP). In general, in the PBAP approach, each subscriber is given an access priority class (i). Each access priority class (i) has a certain probability P_It'sOnly access requests with The class with the highest priority (class 0) always transmits an access request whenever it has an access request. For example, P₀ = 1 (higher priority) and P₁ = 0.5 (low priority). Each access priority class also has a different maximum number of retries. A lower access priority class has a lower maximum number of retries.</p><p>In the access priority embodiment of Figure 9, the remote terminal receives (in memory) and stores (in memory) the following access priority system parameters broadcast by the base station in step 901: the logical existing between the remote unit and the base station. M, the number of access channels; Probability P for each class (i)_It's; and K, which is the maximum number of transmission retries associated with class (I)._It's, where P_It's = 1 and P_It's &lt; P_i+1, K₀ = K_maxand K_i+1 &lt; K_It's.</p><p>Accordingly, in step 902, the remote unit (via its associated processor) determines whether a new access request is required due to receipt of the transmitted packet. If so, in step 904, the remote terminal sets the variable no_tx = 0. This is a retransmission attempt variable. In step 906, the remote terminal determines that x &gt; (1 - P_It's) to decide whether It should be understood that x is a random variable uniformly distributed between 0 and 1. x is (1 - P_It's), the remote terminal waits for the next available access slot in step 908 and then returns to step 904 to repeat the process. x &gt; (1 - P_It's), the remote terminal selects a logical access channel (1, ..., M). Then, in step 912, an access request is sent to the selected logical access channel. In a next step 914, the terminal determines whether the access request has been successfully received by the base station. Again, this is accomplished by the base station sending an access request acknowledgment message to the terminal (step 1106 in Fig. 11). If the access request is successful, the access priority control method ends (step 916), and the remote terminal may transmit the packet according to the packet forwarding structure used in UMTS.</p><p>However, if the request is not successful, in step 918, the terminal increments the variable no_tx by one. In step 920, no_tx is K_It'scompared to no_tx is K_It's If greater than, the current access request is canceled (step 922). If the maximum number of retransmissions has not been reached, then in step 924 a backoff process is performed. In another method embodiment, the backoff process is the same as described above in step 618 of FIG. 6 . After the backoff, the remote terminal waits for the next available access slot at step 908 and then returns to step 904 to repeat the process.</p><p>Referring now to FIG. 10, there is shown a flow diagram of a method 1000 for controlling access priority at a remote terminal in accordance with a sixth embodiment of the present invention. It should be understood that the method is performed at a remote terminal (eg, terminal 2 or 4) that has generated or received a packet uplinked to a UMTS base station (eg, base station 6). The embodiment shown in FIG. 10 is hereinafter referred to as Retransmission Based Access Priority (REBAP). In general, in the REBAP approach, it is assumed that every access request has an access packet priority (APP) associated with it. The REBAP structure gives retransmitted access requests a higher priority than new access requests. This property is advantageous for certain applications that require a 95th or 99th percentage access delay that is less than a smaller average access delay for every successful attempt. All new access requests have the lowest AP rating (n_max - 1) is given. Then, the priority is dynamically adjusted based on the number of retransmissions. An access packet can access all M logical access channels, but depending on the access packet priority class, it chooses a different random chip delay. The lowest APP class has the highest average random chip delay distribution from which to choose. An access request that fails and needs to be retransmitted has an adjusted APP class. Note that in addition to the APP characteristics, an Access Service Priority (ASP) class may also be defined. The request with the highest ASP, say grade 0, automatically increments the APP of failed access requests with each retry. Having a lower ASP adjusts the APP of failed attempts less aggressively. For example, ASP class 1 increases the APP of access requests only after two failures .</p><p>In the access priority embodiment of Figure 10, the remote terminal receives (in memory) and stores the following access priority system parameters broadcast by the base station in step 1001: the logical existing between the remote terminal and the base station. M, the number of access channels; For each class (i), there are two numbers associated with it, i.e. K, the maximum number of retransmission attempts for each class (i)._It's and RN representing random chip delay for each class (i)_It'sAPP having . Also, APP is 0, ..., n_maxIt is in the range of -1, and 0 is assumed to have a higher priority. If ASP is used, the parameters ASP and S_jis also transmitted by the base station and received and stored by the remote terminal. S_jdenotes the number of retransmissions required for class j before the APP of the access request from class j is updated. So, K._It'sis related to the APP priority rating, and S_jis related to the ASP priority class. For example, for ASP = 0, 1, 2; S₀ = 1, S₁ = 3, S₂ = 5.</p><p>Thus, in step 1002, the remote terminal determines whether a new access request is required due to receipt of a transmitted packet (via its associated processor). If so, in step 1004, the remote terminal determines that APP = n_max - 1, ASP = j, no_tx - 0, and adj = 0 (adj will be described later). Then, in step 1006, the remote terminals are distributed (RN_It's, ..., RN_It's') to select a random chip delay. In step 108, the remote terminal selects a logical access channel (1, ..., M). The access request is transmitted to the logical access channel selected according to the chip delay in step 1010 . In the next step 1012, the terminal determines whether the access request has been successfully received by the base station. This is accomplished by the base station sending an access request acknowledgment message to the terminal (step 1106 in FIG. 11). If the access request is successful, the access priority control method ends (step 1014), and the remote terminal may transmit the packet according to the packet forwarding structure used in UMTS.</p><p>However, if the request is not successful, in step 1016, the terminal increments the variables no_tx and adj by one. The variable no_tx represents the number of times an access request has been transmitted by the remote terminal, and adj represents a variable used to check whether Sj has been reached. In step 1018, no_tx is K_It'scompared to no_tx is K_It'sis greater than or equal to, the current access request is canceled (step 1020). However, no_tx is K_It'sis not equal to or greater than Sj, the remote terminal checks whether adj is equal to or greater than Sj (step 1022). Otherwise, the APP remains the same as set in step 1004 . Then, in step 1024, a backoff process is performed. The backoff process is the same as described in step 618 of FIG. 6 . After the backoff, the remote terminal waits for the next available access slot at step 1026 and then returns to step 1006 to repeat the process. However, if adj is equal to or greater than Sj, APP is decremented by 1 (APP = n-1), thereby increasing the priority of the retransmitted request (step 1028). Also, adj is reset to zero in step 1028. Then, in step 1024, a backoff process is performed. After the backoff, the remote terminal waits for the next available access slot at step 1026 and then returns to step 1006 to repeat the process.</p><p>It is understood that the access priority method of the present invention as described herein is useful and advantageous in a variety of applications. A few examples of these applications are given briefly below. In the existing wireless access system, permission is not provided to allow urgently needed users to access with higher priority than other types of users. One possible implementation of the access priority according to the present invention is to reserve some logical access channels for access only by emergency users. In still other cases, a distinction may be made between different types of customers based on the service fee paid by the service provider in accordance with the present invention. The CEO wants to have smaller access delays so that his messages can reach over the network faster than others. Preferably, this service is linked with service priority to ensure that the user can better detect end-to-end delay. Also, to provide a smaller access delay for some real-time services, for example interactive video, again this purpose can be achieved using the access priority feature of the present invention. In addition, the present invention provides a new access characteristic included in the UMTS MAC. Access priorities can be used in conjunction with scheduling algorithms to provide different quality of service to customers based on service charges, urgency needs, or delay requirements.</p><p>Although embodiments of the present invention have been described herein with reference to the accompanying drawings, the present invention is not limited to these detailed embodiments, and various other changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention. It should be understood that modifications may be made. For example, although certain variations of the embodiments described in the flowcharts have been described above, it should be understood that the present invention contemplates combining the embodiments or variations thereof with one or more other embodiments or variations thereof.</p><p>ODMAFQ MAC protocol operation</p><p>The overall ODMAFQ MAC protocol operation is illustrated in the flowcharts of FIGS. 12A and 12B . As seen from the remote host (terminal) as shown in Fig. 12a, after establishing the power level for uplink transmission (1210), the remote host sends each remote terminal equipped with a packet request access to the AP (base station). It participates in forwarding uplink initial contention 1215 . If some of these access requests are made in the same intended minislot and collide ( 1220 ), the conflicting remote host participates in uplink conflict resolution ( 1225 ). If not, the AP allocates 1230 the uplink bandwidth between the remote host requested access, followed by an allocation 1235 of bandwidth for its own downlink transmission. Each remote host waits to receive a transmit grant 1237 during a subsequent downlink transmission, and if so, transmits the waiting packet from the queue. If the remote host's queue is not empty ( 1238 ), the remote host returns to where it waits for further transmission permission ( 1237 ), otherwise it waits for a new packet to arrive ( 1239 ).</p><p>As shown in FIG. 12B , the AP monitors ( 1260 ) activity in the received contention scheduled slot. Upon receiving a successful access request (1265), the AP delivers an expected acknowledgment (ACK) (1270) and adds the successful remote host to the schedule list (1275). If there is no new successful access request ( 1265 ), the AP also monitors the uplink dataslot 1280 unless the schedule list is empty, and when it successfully receives a transport packet ( 1285 ), it responds with a data ACK ( 1290 ). ). The AP then schedules the downlink packet ( 1240 ), schedules the uplink transmission of the successfully asserted remote host ( 1245 ), communicates the associated transmission grant ( 1250 ), and also transmits the downlink data packet ( 1255 ). and then returns to monitoring operation in the scheduled contention slot (1260).</p><p>It is desirable to allow for optimal channel maintenance characteristics so that each queue can be left empty for a short period of time without the access point releasing bandwidth reservations. This allows high-priority users to remain on the base station reserved bandwidth list for an allotted time before being released, thereby lowering the latency of real-time packets (i.e. voice communications) by preventing processing of all setup signaling messages required for channel reservations. (no or little delay) for packets of time-sensitive data, such as Using this property, a timer is triggered in the wireless modem when the queue is empty. As long as a new packet arrives at the radio modem before this timer expires, the radio modem does not need to make a new access request. At the AP, when this feature is turned on, the AP grants this particular radio modem permission to transmit one data slot per alternating uplink frame, even if the queue appears empty for the last uplink data transmission from the radio modem. will continue to allocate. The AP will also start a timer. If the timer expires and the AP has not received a new packet from the wireless modem, the AP removes the wireless modem from the list of reserved bandwidths. This channel maintenance feature is particularly useful when the bandwidth scheduling process takes time to complete, so that it is not too far apart to guarantee separate bandwidth reservation requests through contention for each data packet without arriving in a row. Allows low latency for period packets. However, for burst sources that do not require this channel maintenance feature, when a packet arrives and looks for an empty buffer, the modem continues to pass an access request to the AP through one of the contention minislots.</p><p>13A illustrates an embodiment of an access control method. In each uplink frame, N contention scheduled minislots are configured. The N minislots are organized into multiple access priority classes, and each class has a different priority. The AP is configured to allow m access priority classes (1315). Each remote host of the access priority class (i) randomly selects one contention minislot (1320) and transmits an access request, and the selected contention minislot is N_(i+1) &lt; N_It'sand N₁ 1 to N when = N_It'sis in the range of The base station receives (1325) the access request and sequentially examines the received contention minislots. If the currently investigated minislot contains a non-conflicting request ( 1330 ), the AP grants access to the remote host corresponding to the non-conflicting access request ( 1835 ). If the minislot currently under investigation contains a conflicting request (1330), the AP does not forward an ACK and causes the affected remote node to perform conflict resolution (1340). After a conflict resolution cycle, the AP is called a "winning". Grant access to the remote host (1345). On the other hand, if there are more minislots to be investigated (1350), the AP continues to search for conflicting minislots (1330), granting access to the successful requesting host (1335), or waiting for the result of conflict resolution (1340).</p><p>13B is a flowchart illustrating another embodiment of an access control method. The N minislots are organized into multiple access priority classes, each with a different priority. N contention scheduled minislots are configured in each uplink frame 1310 . The N minislots are organized into multiple access priority classes, and each class has a different priority. The AP is configured to allow m access priority classes (1315). Each remote host with an access priority class (i) with a stack level of 0 is P_(i+1) &lt; P_It'sand P₁ = 1 probability P_It'sTransmits an access request with (1360). The base station receives the access request (1325) and sequentially examines the received contention minislots. If the currently investigated minislot contains a non-conflicting request ( 1330 ), the AP grants an access ( 1335 ) to the remote host corresponding to the non-conflicting access request. If the minislot currently under investigation contains a conflicting request (1330), the AP does not forward an ACK and causes the affected remote node to perform conflict resolution (1340). After a conflict resolution cycle, the AP is called a "winning". Grant access to the remote host (1345). If there are more minislots to be investigated (1350), the AP continues to search for conflicting minislots (1330), granting access to the successful requesting host (1335) or waiting for the result of conflict resolution (1340).</p><p>IDLE, SUCCESS, and COLLISION status information is carried back to the wireless modem. The AP places the slot status information in the downlink scheduled acknowledgment field. Three other preferred conflict resolution methods can be used. The first method is proposed in the IEEE 802.14 standard, and will be described later along with two new methods. Simulation results show that the second method to be described provides better access delay.</p><p>In the first collision resolution method proposed in IEEE standard 802.14, each wireless node that wants to transmit randomly selects one of the reserved minislots. When a collision appears, the modem affected by the collision retransmits based on a random binary-exponential back-off method. This backoff method works as follows:</p><p>One. Modem is 0 and 2^j - Generate a uniformly distributed random number I between 1, where j is the number of collisions the modem has experienced for the packet it is trying to transmit. If j is greater than 10, then I is 0 and 2¹⁰ It is chosen from a uniform distribution between -1.</p><p>2. The modem skips the next I-1 contention slot opportunity of the same type (minislot or data contention slot) and then retransmits the collided packet prior to the immediately next contention slot opportunity.</p><p>The operation of this method is illustrated in FIG. 14A . The wireless node waiting to access the AP selects (1402) a scheduled minislot to transmit the access request. If the node is affected by the collision ( 1404 ), it generates a random number I ( 1408 ) and skips ( 1410 ) the next I-1 contention slot opportunity of the same kind. The node then retransmits (1412) the access request for the packet that collided with the immediately next contention slot opportunity. If the node is unaffected by the collision ( 1404 ) and the queue at the node is empty ( 1405 ), the node transmits ( 1406 ) the packet and returns to the waiting state ( 1402 ). If the queue in the node is not empty (1405), after receiving permission to transmit from the AP, the node transmits the current packet with an additional scheduled request for transmission of the next packet in the queue (1407), and if the queue is empty ( 1405) until the last packet is transmitted (1406), after receiving the transmission permission, it continues to transmit packets with an additional scheduled request (1407), after which the node returns to the standby state (1402).</p><p>In the second and third methods, the AP broadcasts the result of each content in the scheduled minislot to all wireless nodes via a downlink broadcast message. In the second method, each wireless node's modem is characterized by a stack level, and only wireless nodes with a stack level equal to zero are permitted to transmit access request packets. Modems with a stack level greater than zero are considered pushed. For example, when there are M reserved minislots, each remote node with stack level 0 may randomly select one of the M minislots. At the end of the time slot, the wireless node i changes the stack level based on the transmission result in that time slot. This method allows a newly activated radio node to join an existing radio node with stack level 0 for a specific collision resolution period. Each wireless node in the request state increments the stack level by one if it receives a negative acknowledgment (eg, there is a conflict) from the base station (AP) and does not send an access request packet. On the other hand, the wireless node decrements the stack level by one when it receives a positive acknowledgment from the base station indicating successful transmission of the access request. Each wireless node participating in the sending of an access request determines whether the stack level remains at level 0 or is incremented by 1 when receiving a negative acknowledgment from the base station.</p><p>The second rule of thumb is:</p><p>One. When a wireless node wants to first seek access to the network or forward new data with the requested access, it is placed in the request state and assigned a stack level of zero.</p><p>2. When there are M reserved minislots, each wireless node in the request state randomly selects one of the M reserved minislots, which is a designated minislot for transmitting an access request packet.</p><p>3. When a wireless node is characterized by a stack level of zero, it sends an access request packet, but when a remote node is characterized by a non-zero stack level, it does not send an access request packet.</p><p>4. At the end of the time slot, each wireless node changes its stack level based on the result of the access request (COLLIDED, IDLE, or SUCCESS) reported for the designated minislot in the scheduled grant field of the downlink message from the access point. make it</p><p> A. The wireless node that has transmitted the access request and received the SUCCESS result is removed from the request state.</p><p> B. The wireless node that receives the COLLIDED result by sending the access request increases the stack level by 1 or leaves the stack level at 0 depending on the randomly selected result.</p><p> C. A wireless node in the request state and not forwarding an access request (i.e., a node pushed to stack level &gt; 0) increments the stack level by 1 if the result reported in the expected grant field for the specified minislot is COLLIDED. .</p><p> D. A radio node in the request state and not forwarding an access request (i.e., a node pushed to the stack level &gt; 0) decrements the stack level by 1 if the result reported in the scheduled acknowledgment field for the specified minislot is SUCCESS. .</p><p>The operation of this method is shown in Figure 14b. A wireless node waiting to access the AP or transfer new data sets the stack level to zero (1432) and enters the request state. If the node's stack level is zero (1434), the node selects (1436) a reserved minislot for transmission of the access request and transmits the access request. If the result of the request is SUCCESS (1438) and the queue at the node is empty (1439), the node transmits the current packet (1440), remains in the request state, and returns to the standby state (1432). If the queue at the node is not empty (1439), after receiving an acknowledgment from the AP, the node transmits (1441) the current packet with an additional scheduled request for transmission of the next packet in the queue (1441), if the queue is empty. It continues to transmit (1441) packets with additional scheduled requests until 1439, after receiving permission to transmit, at which point it transmits (1440) the remaining packets, remains in the request state, and returns to the waiting state. (1402).</p><p>If the output 1436 of the scheduled request is not SUCCESS (1438), the node participates in a random draw (1444) to see whether it increments the stack level by one (1448) or leaves the stack level at zero (1446) (1444). . If the stack level is maintained at zero (1446), the node again selects a reserved minislot for transmitting the access request (1436) and transmits the access request. When the stack level is increased (1448), the stack level does not become zero (1434). If the remote node's stack level is non-zero (1434) and the result of the previous scheduled request was COLLIDED (1450), then the node increments the stack level by one (1452). If the result of the previous scheduled request is not COLLIDED (1450), the node decrements the stack level by one (1454).</p><p>The third conflict resolution method is a modification of the second method. In the third collision resolution method, the modem of each wireless node is again characterized by a stack level, and only wireless nodes with a stack level of zero are allowed to transmit access request packets. Modems with a stack level greater than zero are considered pushed. The third method rule is:</p><p>One. When a wireless node wants to first seek access to the network or forward new data with the requested access, it is placed in the request state and assigned a stack level of zero.</p><p>2. When there are M reserved minislots, each wireless node in the request state randomly selects one of the M reserved minislots, which is a designated minislot for transmitting an access request packet.</p><p>3. When a wireless node is characterized by a stack level of zero, it sends an access request packet, but when a remote node is characterized by a non-zero stack level, it does not send an access request packet.</p><p>4. At the end of the time slot, each wireless node changes its stack level based on the result of all access requests (COLLIDED, IDLE, or SUCCESS) reported in the Predetermined Grant field of the downlink message from the access point.</p><p> A. The wireless node that has transmitted the access request and received the SUCCESS result is removed from the request state.</p><p> B. The wireless node that receives the COLLIDED result by sending the access request increases the stack level by 1 or leaves the stack level at 0 depending on the randomly selected result.</p><p> C. A wireless node that is in a request state and has not delivered an access request (i.e., a node pushed to stack level &gt; 0) is the result of all access requests reported in at least 80% of the expected grant fields (or some other predetermined threshold). If is SUCCESS or IDLE, decrease the stack level by 1. Otherwise, the remote node increments the stack level by 1.</p><p> D. When the overridden modem stack level is reduced to zero, the modem re-passes the request to one of the M minislots (or if the access priority is enforced, I_It's mini slot).</p><p>The operation of this method is shown in Fig. 14c, which is similar to the method of Fig. 14b. A wireless node waiting to access the AP or transfer new data (1432) sets the stack level to zero and enters the request state. If the node's stack level is 0 (1434), the node randomly selects a predetermined minislot for transmission of the access request (1436) and transmits the access request. If the result of the request is SUCCESS (1438), and the queue at the node is empty (1439), the node transmits the current packet (1440), maintains the request state, and returns to the standby state (1432). If the queue at the node is not empty ( 1439 ), after receiving permission to transmit from the AP, the node transmits ( 1441 ) the current packet with an additional scheduled request for transmission of the next packet in the queue ( 1441 ), and if the queue is empty and After receiving the transmission permission until the remaining packets 1440 are transmitted (1439), the packet having an additional scheduled request is continuously transmitted (1441), and thereafter, the request state is maintained and the standby state is returned (1402).</p><p>If the result of the scheduled request (1436) was not SUCCESS (1438), then the node participates in a random draw (1444) to know whether to increment the stack level by one (1484) or leave the stack level to zero (1446) (1444). . If the stack level is maintained at 0 (1446), the node again randomly selects a predetermined minislot for transmission of the access request (1436) and transmits the access request. If the stack level is increased (1448), the stack level is non-zero (1434). If the remote node's stack level is non-zero (1434) and the result of all scheduled requests during the previous cycle was COLLIDED while equal to or greater than some THRESHOLD percentage (1460), the node increments the stack level by one (1462). If the result of the previous scheduled request was not COLLIDED (1460), the node decrements the stack level by one (1464).</p>

<p>Therefore, according to the present invention, some parameters or parameters are associated with the access priority class to influence the likelihood of the remote terminal completing a successful access request to the base station, thus addressing the unique requirements associated with a broadband multimedia communication system. A method and apparatus are provided for providing access priority in UMTS.</p>