MXPA99009291A - Method and apparatus for priority of random chip delay access in a communication system - Google Patents

Abstract

The present invention provides methods and apparatus for providing access priority in a MAC protocol of a communication system such as, for example, with respect to RACH UMTS. In particular, the invention introduces various access priority methodologies that include: (i) random chip delay access priority (RCDAP); (ii) access priority based on random backward movement (RBBAP); (iii) access priority based on variable logical channel (VLCAP) (iv) access priority based on UMTS specific variable logical channel (VLCAP ') of probability-based access priority (PBAP), and (vi) access priority based on retransmission (REBAP). Each methodology associates some parameter or parameters to the access priority classes in order to alter the probability that a remote terminal completes a successful access request with a radio station.

Description

METHOD AND APPARATUS FOR PRIORITY OF RANDOM CHIP DELAY ACCESS IN A COMMUNICATIONS SYSTEM FIELD OF THE INVENTION The present invention relates to method and apparatus for providing priority control of access in a communication system and, more particularly with methods and apparatus for providing access priority control in a protocol of reaction to means of a communication. universal mobile telecommunications system.

BACKGROUND OF THE INVENTION A great effort is being made in the last decade to integrate multimedia capabilities (from multiple media) to mobile communications. The International Telecommunications Union (ITU) and other organizations have tried to develop standards and recommendations to ensure that the mobile communications of the future are capable of supporting multimedia applications with at least the same quality as existing fixed networks. In particular, many global research projects have been sponsored in order to develop such mobile systems of the next generation (third). The Research and Development and Advanced - REF .: 31347 Communications Technology in Europe, RACE-1 and RACE-2 and Advance Communications Technology and Services (ACTS) are examples of such efforts in Europe. It is known that in order to provide end users with the necessary quality of service for multimedia communications, internet access, video / image transfer, high bit rate capabilities are required. Given such requirements, the carrier capabilities look for a third generation system that has been defined as 384 kilobits per second (kb / s) for a full coverage area and 2 megabits per second (Mb / s) for a local area coverage . The Universal Mobile Telecommunications System (UMTS) is a new radio access network based on broadband code division access access of 5 Megahertz (W-CDMA) and is optimized to support third-generation services that include mobile communications capable of multimedia. Since the main design objectives of UMTS are to provide a broadband multimedia communication system that integrates the infrastructure for mobile and fixed communications and offer, for example, the same range of services that are provided by fixed and wireless communications networks , UMTS must provide circuit switched as well as packet switched services, and a variety of mixed media traffic type, and bandwidth based on demand. However the providing multimedia support implies the need for flexibility, that is, that is capable of supporting services with different bit rates and Eb / N0 requirements and multiplexing such services in a multi-service environment. It is designed to UMTS to support such demands. With reference to Figure 1, an exemplary block diagram of a UMTS access network is shown. Particularly a plurality of remote terminals 2 and 4 (for example mobile terminals) communicated with the base stations (NODE-B) 6 by means of wireless links 8 -CDMA.The remote terminals can be of a variety of devices such as a wireless telephone 2 or a laptop computer 4 with an internal or external modem In the UMTS standard, a base station is called a NODE-B.These base stations communicate with a network component that provides management functions of radio resources and is called Radio Network Controller (RNC) Since UMTS is a W-CDMA system, soft transfers are supported In the case of soft transfers, there are two base stations 6 that serve a remote terminal. therefore, the remote terminal sends frames to these two base stations, when the two base stations receive the frames from the remote terminal, they are sent to a Frame Selector unit. Unit reader (FSU). The FSU decides which is the best framework, in terms of frame quality, to be sent to the network of core. In the UMTS, the FSU may be physically integrated with the RNC and as such, in Figure 1, the RNC and FSU are shown as block 10, but may also be functionally separated, as in block 12 (FSU) and the block 14 (RNC). Other elements in the UMTS network perform conventional functions such as: 20 xLR databases, which provide source and appointment position information, and joint work function units (IWF). It will be appreciated that the universal mobile switching center (UMSC) 16 serves as the mobile switching center for the base stations 6 in the UMTS. The subnets 18 are wireless service provider networks and CNI to CNn are the core networks 24 to which the remote terminals are finally attached. With reference to Figure 2, a diagram of the typical protocol stack in UMTS is shown. In UMTS, layer 1 (Ll) is the physical layer (PHY) which provides information transfer services to the MAC layer (media access control) and upper layers. The transport services of the physical layer are described by the way in which feature data is transferred over the transport channels of the radio interface. Layer 2 (L2) is composed of sublayers which include MAC, LAC (link access control) and RLC and RLC (radio link control). In UMTS, the functions performed in RLC are divided and therefore two RLC protocols (RLC and RLC) are specified. The RLC and MAC layers provide services in real time and not in real time. The MAC layer controls but does not transport the multiplexing of data streams that originate from different services. That is, the MAC layer, by means of logical channels, allows common physical communication channels (for example, a broadcast channel) to be shared by many remote terminals. IP (internet protocol) is the network layer. The term "Uu" refers to the specific interface for UMTS between a remote terminal and a base station, while the term "Iub" refers to a specific interface for a UMTS between the base station and the RNC / FSU. Layer 2 of the radio access network (that is, the left side ddl NODO-B in the protocol stack) is divided into RLC and MAC layers, while layer 2 of the core network (that is, the right side of the NODE-B in the protocol stack) is more related to the technology used for transport network layer frames, for example, ATM (asynchronous transfer mode) or frame relay. IP is shown as the transport protocol, however, UMTS is not limited in this way. That is, UMTS can provide other transport protocols. Additional details regarding the protocol layers can be found in Dahlman et al., "UMTS / IMT-2000 Based on Wideband CDMA," IEEE Communications Magazine, pp. 70-80 (September 1998) and in ETSI SMG2 / UMTS L2 & L3 Expert Group, "MS-UTRAN Radio Interface Protocol Architecture, Stage 2," Tdoc SMG2 UMTS-L23 172/98 (September 1998). In UMTS, four types of application traffic need to be handled. These include: (i) applications that are sensitive to both delay and loss, for example, interactive video; (ii) applications that are sensitive to loss but that can tolerate moderate delay, for example interactive data; (iii) applications that are sensitive to delay but tolerant of moderate losses, for example, speech; and (iv) applications that are tolerant of both delay and loss, for example, file transfer. To provide a quality of service (QoS) for all these different applications, the UMTS system must be designed appropriately. Several important issues must be considered in the design of a UMTS system such as, for example, how to satisfy QoS without wasting network resources and how to operate the systems in the stable region when all types of traffic are downloaded simultaneously. In addition, several components are required in UMTS to support variable QoS, for example, the service parameters needed to be defined to allow different applications to specify their different QoS requirements, for example, the guaranteed service parameters and controlled load service defined by the strength of internet engineering tasks (IETF). Users can request bandwidth resources either in a download mode or in a connection mode. In addition, there must be an admission control component in UMTS that makes decisions so that the requests of the users are granted or not. The admission of new applications must be done in such a way that even when all admitted applications occur simultaneously, the QoS requirements of each application will not be violated (unless there are requests for better effort). In addition, once the user's request is admitted, there must be features implemented in the UMTS network to provide such service guarantees, for example, delay request, packet loss requirement. The algorithms of elaboration of protocols in the network nodes and the marking of packages for traffic of non conformed users are some of the characteristics that can be supported by the route allocators to provide differentiated services. In order to provide end-to-end QoS in UMTS, certain features in the MAC layer need to be provided to ensure different QoS. One possible way to provide different QoS is by providing priority mechanism. Priority mechanisms can be implemented in terms of access priority, service priority or intermediate memory management schemes. There are several types of service priority mechanisms, for example, fixed priority, dynamic priority. The fixed priority mechanisms include, for example, strict priority and weighted round table. Dynamic priority schemes include, for example, net shared row, net shared row of auto-clock, and net shared row disciplines of the worst case. With respect to access priority, several well-known channel access protocols are currently used in wireless data systems, such as Slotted Aloha, PRMA, etc. The conventional Slotted Aloha system is a relatively simple protocol but, because it does not attempt to avoid or resolve coalitions between data users, its theoretical capacity is only 0.37. 'Reservation-based protocols attempt to avoid and resolve collisions by dynamically reserving channel bandwidth for users who need to send packets. Typically, in such protocols, a channel is divided into intervals that are grouped in frames of N intervals. An interval can be further subdivided into k mini-slots. Normally, A ± of the intervals will be used for reserve purposes while the remaining intervals -Aj are data intervals. Users who need to send packages, send a reservation request in one of the mini-slots B = A2 * k. If the success is Reservation request package, then the user will be assigned a certain number of data intervals until the user or the base station releases the reservation. If the reservation request package is not successful, the user will use a conflict resolution method to retransmit the reservation request until it is successfully transmitted. The access priority control is particularly critical with respect to one of the logical channels associated with the media access control protocol (MAC) of the UTMS, specifically, the random access channel (RACH). RACH is a common uplink transport channel used to carry control information and short user packets from a remote terminal. With reference to Figure 3, a block diagram of an exemplary physical element (hardware) implementation of a non-coherent RACH detection algorithm for use in a UMTS base station (NODE-B in Figure 1) is shown. The RACH receiver 30 is capable of providing the following functions: detection, demodulation, decoding and recognition. The purpose of the detection is to determine if an RACH download has been sent, subsequently described by a remote terminal and resolve the strongest multiple path components of the incoming discharge. The receiver 30 also demodulates and decodes the message contained within the RACH corresponding to determine the remote terminal identifier and the requested service. After decoding a remote terminal RACH transmission, the receiver generates a recognition signal which transmits the base station to the remote terminal on an advance access layer (FACH). The RACH receiver 30 preferably performs the above functions according to the following structure. An RACH transmission download is received and demodulated by the mixers 32 and then filtered in the filters 34. The signal is then displayed in the sampling unit 36. The broadcast eliminator 38 decodes the signal according to the broadcast sequence, in this case the gold code 512 (512 Gold). The decoded signal is stored in buffer (buffer 40) and sent to a time offset unit 50. In addition, the output of the broadcast eliminator 38 is provided to the integrator 42. The outputs of the integrator 42 are mixed (mixer 44) and provided to the timing detector 46 and then to the threshold detector 48. The output of the threshold detector 48 indicates whether a valid signal is received from the remote terminal. This result is provided to the time deviation unit 50. If it is a valid signal, (ie, above the predetermined thresholds), the decoded signal is sampled down the unit 52. Subsequently, based on the preamble described below, the signal passes through the cover filter unit 54 to the preamble signing searcher 56. The output of the sought 56 provides the base station with the identifier of the remote terminal and information regarding the service or services requested by the remote terminal. It is known that the physical RACH is designed based on the Slotted ALOHA solution. A remote terminal can transmit a random access download 100 in eight well defined timeslots (access interval # 1, ..., access interval #i, ..., access interval # 8) in relation to the limit of frame of the received broadcast control channel (BCCH) of the current cell, as illustrated in Figure 4A. As shown in Figure 4B, the random access download consists of two parts, a preamble part 102 of length of 1 millisecond (ms), a message part 104 of length of 10 ms, and a length of free time 106. 0.25 ms between the preamble part and the message part. There are a total of 16 different preamble signatures that are based on orthogonal gold code (orthogonal Gold) adjusted for length 16 (gold code 512). The information in the available signatures and the time displacements are disseminated in BCCH. Based on this structure, if the receiver has 128 parallel processing units (16 preamble signatures multiplied by 8 time slots), 128 random access attempts can be detected simultaneously. In other words, we have 128 Equivalent random access channels for a maximum configured base station for the current cell. Accordingly, there is a need for methods and apparatuses that provide access priority in UMTS that meet the unique requirements associated with such a broadband multimedia communication system. Specifically, there is a need for methods and apparatus to provide access priority with respect to UMTS RACH.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides methods and apparatus for providing access priority in a MAC protocol of a communication system such as, for example, with respect to UMTS RACH. Particularly, the invention introduces several access priority methodologies that include: (i) a random chip delay access priority (RCDAP); (ii) an access priority based on random backward movement (RBBAP); (iii) an access priority based on variable logical channel (VLCAP); (iv) an access priority scheme based on variable logical channel for the specific variation of UMTS (VLCAP '); (v) probability-based access priority (PBAP); and (vi) access priority based on retransmission (REBAP).

In one aspect of the invention, RCDAP methods and apparatus are provided. In RCDAP, each priority class is advantageously assigned with a chip delay different from chip delay distributions before sending a request for access to the base station. Preferably, those classes with higher priority are provided with a lower average random chip delay so that their access requests will have a higher probability of being picked up compared to those sent by users with a lower priority class. In another aspect of the invention, RBBAP methods and apparatus are provided. In RBBAP, each priority class is advantageously assigned by a different backward delay. Preferably, the requests associated with higher access priority will have a smaller average backward delay. Whenever there is a collision or some other reason in which the access request is not successfully received at the base station, the remote terminal, based on class i, chooses a random delay distributed among a predetermined interval. In a further aspect of the invention, VLCAP devices and methods are provided. In VLCAP, each subscriber is provided with an access priority class i. Preferably, those with the highest priority have access to the entire logical access channel for which the base station is configured, while those with a lower priority are given access only to a small subset of logical access channels. For example, only a preamble signature with 8 time shifts. The reasoning behind this solution is that a larger number of logical accesses in the remote terminal must be chosen, and the probability of finding a channel over which the request will be successfully transmitted is greater. In a further aspect of the present invention, variations of the VLCAP apparatus methods specific for UMTS are provided. The VLCAP 'solution specifically takes into account a special UMTS access channel structure. That is, although there are t time shifts for each preamble signature, there may not be t parallel processing units in the base station due to a limitation in the processing complexity associated with the base station. For example, there may be only four receivers with each receiver programmed for pick-up, for example, the time shifts (ith, (i + 4) ß8th). Therefore, according to the VLCAP 'solution, those requests with lower priority classes will be assigned a higher number for time shifts, and therefore higher priority access requests are allowed to be fetched by the first receivers.

In a further aspect of the invention, PBAP methods and apparatus are provided. In PBAP, each subscriber is provided with an access priority class i. Each access priority class i can only transmit access requests with a certain probability Pi. Those with a higher priority will always transmit their access requests whenever they make such a request for access. In another aspect of the invention, REBAP methods and apparatus are provided. In REBAP, access requests have an access packet priority (APP) associated with them, so retransmitted access requests are given a higher priority over new access requests. It will be appreciated that the access priority techniques implemented in accordance with the present invention may include a combination of more than one of the above embodiments. For example, RCDAP can be performed with RBBAP or VLCAP and PBAP, and so on. These and other objects, features and advantages of the present invention will become apparent from the following detailed description of the illustrative embodiments thereof, which should be read together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of a UMTS access network; Figure 2 is a diagram of, a protocol stack associated with a UMTS; Figure 3 is a block diagram of a non-coherent RACH receiver for use in a UMTS; Figures 4A and 4B illustrate access slots and a structure of a random access download used in an RACH UMTS; Figure 5 is a flowchart of an access priority control method to a remote terminal according to a first embodiment of the present invention; Figure 6 is a flowchart of a remote access control method for a remote terminal according to a second embodiment of the present invention; Figure 7 is a flowchart of an access priority control method to a remote terminal according to a third embodiment of the present invention; Figure 8 is a flowchart of an access priority control method to a remote terminal according to a fourth embodiment of the present invention; Figure 9 is a flowchart of an access priority control method to a remote terminal according to a fifth embodiment of the present invention; Fig. 10 is a flowchart of an access priority control method to a remote terminal according to a sixth embodiment of the present invention; Fig. 11 is a flowchart of an access priority control method to a base station according to the present invention; Figure 12A is a flow chart illustrating the operation of the total ODMAFQ protocol, when viewed by the remote host; Fig. 12B is a flow chart illustrating the operation of the total ODMFAQ protocol, observed by the base station; Fig. 13A is a flow chart illustrating one embodiment of a method for ODMAFQ access control; Fig. 13B is a flow chart illustrating an alternative embodiment of a method for ODMAFQ access control; and Figures 14A-14C are flowcharts that illustrate three ODMAFQ containment resolution methods.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The present invention is described below with the context of access priority control in the MAC layer of the UMTS, particularly with respect to access priority control in the random access channel or RACH. However, it will be appreciated that the teachings of the invention discussed herein are not limited in this manner. That is, the access priority methodologies of the invention are applicable to other communication systems where remote terminals (eg mobile or landline) make random attempts to secure access to a communication channel associated with a base station or other access point in a communications system. Furthermore, it should be understood that the methodologies described herein for use in a remote terminal or a base station are executed by one or more processors associated therewith respectively. The term "processor" as used herein is intended to include any processing device, including a CPU (central processing unit) and associated memory.

Consequently, the instructions of programming elements (software) or codes associated with the implementation of the methodologies of the present invention can be stored in an associated memory and, when it is ready to be used, can be recovered and executed by a CPU appropriate In addition, the term "remote terminal" refers to any device capable of communications with a base station. For example, a remote terminal may be mobile (for example, a cordless telephone or a portable personal computer with a wireless modem) or fixed (for example, a fixed personal computer with a wireless modem). In addition, the terms "base station" and "node_b, "(node_b) are used interchangeably herein As noted above, the present invention relates to subject matter described in the patent application described as United States application serial number 09 / 084,072, filed May 22. of 1998, entitled: "Method for Access Control in a Multiple Access System for Communications Networks," where another MAC protocol is described, denominated as "net multiple access row based on demand" ("on-demand multiple access fair" Queuing "or ODMAFQ A section entitled" ODMAFQ MAC protocol operation "describing the related MAC functions follows the detailed description of the present invention With reference again to Figure 1 and as previously mentioned, it should be understood that the remote terminals 2 and 4 are coupled to the UMTS access network through a wireless interface with the base stations 6. In order to establish communications, the remote terminals send and receive media access control frameworks (MAC) over the wireless interface with the base stations 6. In the case of terminal 4, an internal or external modem can be used to provide a wireless connection to the base stations. A remote terminal such as remote terminal 2 typically has its own internal modem. However, packets are typically generated or received at the remote terminal on a random download basis. The packets are buffered in the remote terminals until they are transmitted in an uplink to the base station. The base stations 6, as is known, provide wide area wireless coverage and multiplex remote terminal traffic from their respective coverage area to the system mobile switching center, for example, UMSC 16 in Figure 1. The stations Base stations also broadcast (perform downlinks) packets that are destined for one or more of the remote terminals in their cell. The UMTS multiple access scheme is a system of time slots (ie, Slotted ALOHA solution) in which a random access channel (RACH) and a packet transmission channel are formed on a basis interval by interval. The duration of the time interval in each channel is chosen based on the particular system implemented. Generally, remote terminals that have packets to send transmit access requests through RACH to a base station. Due to the potentially large number of remote terminals compared to the relatively small number of access channels that a base station is configured to support, access priority schemes are necessary to ensure orderly and timely handling of network traffic. That is, given the fact that many remote terminals can randomly seek to acquire the use of a single communications channel (that is, they request a channel bandwidth to transfer packets), methods must be implemented to prioritize access requests in the network in order to allow remote terminals with a relatively high need to have access to channel bandwidth associated with a base station, over remote terminals with a relatively low need. Thus, for example, if two remote terminals have packet data to be transmitted to the base station, it is preferred that the access request from the remote terminal with a greater access need be more likely to be received and granted beforehand. than the other remote terminal. However, it should be appreciated that the priority class of the remote terminal is dynamic, that is, it depends on the nature and / or content of the packets to be transmitted and / or the nature of the remote terminal. For example, if the packets represent data that are sensitive to delay (for example, interactive video, voice), or are of a nature that guarantees immediate transmission (for example, emergency situation), then the remote terminal selects a priority class with a priority that is compatible with the situation, that is, in these cases, a high priority. In addition, based on the level of service (for example premium or regular) to which the remote terminal is subscribed, different access priorities are assigned. Referring initially to Figure 11, there is shown a flow diagram of an access priority control method 1100 in the base station according to the invention. In the UMTS, a base station (for example the base station 6) broadcasts (stage 1102) access priority system parameters in a guide or pilot signal to the remote terminals (RT) in its coverage area. As will be particularly explained in accordance with the access priority methodologies performed in the remote terminal, the parameters of the access priority system include parameters that the remote terminal uses in its process of requesting access to the base station. That is, the base station transmits parameters belonging to each pre-established priority class that the remote terminal receives and stores them for use during an access request. In step 1104, the base station (by means of the processor associated thereto) determines whether an access request is received from a remote terminal. If this is not the case, the base station waits to receive one. If a request is received access from a remote terminal, the base station transmits (step 1106) an acknowledgment message to the remote terminal to indicate that the request has been successfully received. This recognition signal is transmitted on an advance access channel (FACH) between the base station and the remote terminal. The base station is then prepared for the reception of packet data from the remote terminal to which access has been granted according to the procedure of receiving packet data used in the UMTS (step 1108). Referring now to Figure 5, there is shown a flow diagram of an access priority control method 500 in a remote terminal according to a first embodiment of the present invention. It should be appreciated that this methodology is performed in a remote terminal (for example terminal 2 or 4) which has generated or received packets that are to be linked up to a UMTS base station (for example base station 6). The embodiment illustrated in Figure 5 is referred to below as a random chip delay access priority (RCDAP). Generally, in the RCDAP solution, each priority class advantageously allocates a different average random chip delay before sending a request to access the base station. It is known that each chip has a certain duration of time and, as such, each chip represents a certain time delay. By therefore, a chip delay time duration is directly related to the number of chips in the delay. Larger delays have more chips than shorter delays. It should be noted that the use of chip delays is due to the use of the CDMA wireless interface (W-CDMA) between the remote terminals and the base stations in the UMTS. According to this embodiment of the invention, those classes with a higher priority are provided with a smaller average random chip delay so that their access requests will have a shorter time delay and therefore a higher probability of be captured compared to those sent by users with a lower priority class. In the access priority mode in Figure 5, the remote terminal, in step 501, receives and stores (in its memory) the following parameters of access priority systems broadcast by the base station: M which is the number of logical access channels which exist between the remote terminal and the base station; Ki, which is the maximum number of retransmission attempts for each class i; a random chip delay for each class i distributed between (RNi.., RN¿ '), where RNX < RNi + 1, RN¿ '< RN? +? '/ For example RN0 < RNX, RN0 '< RNX '. It will be appreciated that i = 0, 1, ..., etc. Therefore, the chip delay associated with access priority class 0 (highest priority) is selected from a chip delay distribution random ones that on average are smaller than the chip delays in the distribution associated with a lower access priority class, for example, class 1. Therefore, a remote terminal classified as class 0 has a higher priority than a remote terminal classified as a class, 1. Accordingly, in step 502, the remote terminal (by means of the processor associated therewith) determines whether a new access request is requested due to the receipt of packets to be transmitted. If so, in step 504, the remote terminal selects a logical access channel (1, ..., M). Then, based on the priority class required (for example, due to the nature or content of the data to be transmitted) or the priority class assigned to the remote terminal (for example, if the user of the remote terminal subscribed to a particular service level, for example, regular or premium) the remote terminal selects a random chip delay from the distribution (RNi, ... RN ± '), in step 506. In this way, if the transmission priority is high, the remote terminal selects from the lowest random chip delay distribution and therefore increases the probability of a request successful If the priority of the transmission is low, the remote terminal selects from the highest random chip delay distribution and therefore decreases the probability of a successful request compared to the terminals remote that request access to a higher priority class. Of course, based on the priority, the remote terminal can select from any random chip delay distribution among them. Then the access request is transmitted according to the selected chip delay in the selected logical access channel, in step 508. Then, in step 510, the terminal determines whether the access request has been successfully received by the base station. This can be carried out by the base station when it transmits an access request acknowledgment message to the terminal (step 11Q6 in FIG. 11). If the access request has been successful, then the access priority control method (block 512) ends and the remote terminal can transmit its packets according to the packet transfer scheme used in the UMTS. However, if the request is unsuccessful, in step 514, the terminal increments a variable, termed as no_tx in one (no_tx ++). It should be understood that the variable no_tx represents the number of times an access request has been transmitted by the remote terminal (the value is stored in the memory associated with the remote terminal processor). In step 516, no_tx is compared with Kx (the maximum number of retransmission attempts for class i). If no_tx is greater than K17 then the current access request is suspended (step 518). It must be understood that priority classes Higher ones are assigned a higher Kx (ie, Kx> Ki + 1) so that more retransmission attempts can be made. If the maximum number of retransmissions has not yet been reached, the retraction process is carried out, in step 520. It should be appreciated that eg retraction procedure is preferably used since, assuming that several remote terminals try unsuccessfully to transmit signals At the same time (the lack of success may be due to, for example, collisions between requests), it is not preferable for each remote terminal to attempt to retransmit approximately at the same time. Therefore, each terminal delays its retransmission by a randomly selected amount of time so as to decrease the collision priority of the retransmitted access requests. In an alternative embodiment, setback is set according to the method of the invention described below with respect to FIG. 6. After backing off, the remote terminal waits, at step 522, for the next available access interval and then return to stage 504 to repeat the process. Referring now to Figure 6, there is shown a flow diagram of an access priority control method 600 in a remote terminal according to a second embodiment of the present invention. Again, it will be appreciated that this methodology is done in a remote terminal (for example terminal 2 or 4) which has generated or received packets to be transmitted in an uplink to a UMTS base station (for example base station 6). The modality illustrated in figure 6 below will be referred to as access priority in, random backward base (RBBAP). Generally, in the RBBAP solution, each priority class is advantageously assigned a different average backward delay. Requests associated with a higher access priority will have a lower average backward delay. Whenever a collision is generated or for some other reason in which an access request is not successfully received at the base station, the remote terminal, based on class i, chooses a distributed random delay between the interval (Di, ..., Say ') with D¿. Di ', O ± < _ D1 + 1, Di1 < . Di + 1 'where class i has a higher priority than class i + 1. In the access priority mode of Figure 6, the remote terminal, and step 601, receives and stores (in its memory) the following access priority system parameters broadcast by the base station: M which is the number of logical access channels which exist between the remote terminal and the base station; Ki, which is the maximum number of retransmission attempts for each class i; a random delay distributed between the interval (Di, ..., Di ') with Di < . Say ', D.¡_. Di + 1, Di1 < . Di + 1 'where class i has a higher priority than the class i + 1. Therefore, the backward delay associated with a higher access priority class is selected from a random backward delay distribution that on average is smaller than the backward delay in a distribution associated with an access priority class less. For example, a remote terminal classified as class 0 has a higher priority than a remote terminal-classified as class 1. Accordingly, in step 602, the remote terminal (by means of the processor associated therewith) determines whether it is required a new access request due to the receipt of packets that will be transmitted. In case this is the case, in step 604, the remote terminal selects a logical access channel (1, ..., M). The access request is then transmitted on the selected logical access channel, in step 606. Then, in step 608, the terminal determines whether the access request has been received successfully by the base station. Again, this can be done by the base station transmitting a terminal access request acknowledgment message (step 1106 in FIG. 11). If the access request has been successful, then the access priority control method (block 610) ends and the remote terminal can retransmit its packets according to the packet transfer scheme used in the UMTS.

However, if the request is unsuccessful, in step 612, the terminal increments the variable no_tx by one. In step 614, no_tx is compared with K? R if no_tx is greater than Ki, then the current access request is suspended (step 616). If the maximum number of retransmissions has not yet been reached, then a rollback process is performed, in step 618. In step 618, based on the required priority class or priority class assigned to the remote terminal, the remote terminal selects a random backward delay of the distribution (Di; ..., DA '). In this way, if the transmission priority is high, the remote terminal selects from the lowest random return portrait distribution and thus increases the probability of a successful request. That is, the backward delay is relatively short so that the retransmission is relatively faster than for the lower classes. If the transmission priority is low, the remote terminal selects from the highest random delay delay distribution and therefore decreases the probability of a successful request compared to the remote terminals requesting access with the highest priority class. Of course, based on the priority, the remote terminal can be selected from any distribution of random backward delay between them. After the recoil, the remote terminal waits, in step 620, by the next available access interval and then return to step 604 to repeat the process. Referring now to Figure 7, there is shown a flow diagram of a method 700 for access priority control to a remote terminal according to a third embodiment of the present invention. Again, it will be appreciated that this methodology is performed in a remote terminal (for example terminal 2 or 4) which has generated or received packets to be transmitted in an uplink to a UMTS base station (for example the base station 6). The modality illustrated in Figure 7 is then demoted as access priority based on variable logical channel (VLCAP). Generally, in the VLCAP solution, each subscriber is provided with an access priority class i. Those with the highest priority (class 0) can have access to all the logical access channels for which the base station is configured (for example 16x8), while those with lower priority are only allowed access to a subset small logical access channels, for example, only a preamble signature with 8 time shifts. The reasoning behind this solution is that the greater the number of logical access channels from which the remote terminal may choose, the greater the probability of finding a channel on which the access request will be successfully tramsmitted.

In the access priority mode in Figure 7, the remote terminal in step 701 receives and stores (in its memory) the following access priority system parameters broadcast by the base station: M which is the number of logical access channels which exist between the remote terminal and the base station; N1 # which is the maximum number of logical access channels of class i to which can be accessed, where Nx > N1 + 1; and N0 = M; Ki which is the maximum number of retransmission attempts for each class i. Accordingly, in step 702, the remote terminal (by means of the processor associated therewith) determines whether a new access request is required based on the receipt of packets to be transmitted. If so, in step 704, the remote terminal selects a logical access channel (1, ..., Ni). That is, the logical access channel of a set of logical channels is selected where the size of the set depends on the priority class of the request. If the request is in accordance with the highest priority class, the remote station can choose from all the logical access channels M while a request with increasing priority has subsets of smaller and smaller size from which to choose. In an alternative mode, the remote terminal can store and then select a random chip delay at this point, from according to the RCDAP solution in Figure 5. The access request is then transmitted over a selected logical access channel, in step 706. Then, in step 708, the terminal determines whether the access request has been received successfully for the base station. Again, this can be done by the base station transmitting a terminal access request acknowledgment message (step 1106 in FIG. 11). If the access request has been successful, then the access priority control method (block 710) ends and the remote terminal can retransmit its packets according to the packet transfer scheme used in the UMTS. However, if the request is unsuccessful, in step 712, the terminal increments the variable no_tx by one. In step 714, no_tx is compared with Kx. If no_tx is greater than Ki, then the current access request is suspended (step 716). If the maximum number of retransmissions has not yet been reached, then a retraction process is performed, in step 718. In an alternative mode, the retraction process is the same as that described above in step 618 of figure 6. After backward, the remote terminal waits, in step 720, for the next available access interval and then returns to step 704 to repeat the process. With reference to Figure 8, a flow chart of a method 800 of an access priority control is shown in a remote terminal according to a fourth embodiment of the present invention. It should be understood that method 800 is a variation of the VLCAP scheme of Figure 7. The variation is referred to as VLCAP 'and specifically takes into consideration a special UMTS access channel structure. That is, although there are 8 timeslots for each preamble signature, there can not be 8 parallel processing units in the base station due to a limitation in processing complexity associated with the base station. For example, there may be only 4 receivers with each receiver programmed to capture, for example, the time shifts (i, th, (i + 4) eslmo)). However, it will be appreciated that the time shifts are not in sequence. That is, the receiver can capture the first four timeslots received, for example, time shifts 1, 3, 5 and 6. Therefore, according to the VLCAP solution, those requests with lower priority classes are it will allocate a higher number for time shifts and therefore access requests of the highest priority classes are allowed to be picked up by the recipients first. That is, if the class is a high priority class, it has few time shifts assigned to it (for example 1 to 4) from which it is selected, while a lower priority class has high time shifts assigned to it (for example 5 to 8) from which it is selected. Therefore, a higher priority access request is more likely to be received compared to lower priority access requests. In the access priority mode in Figure 8, the remote terminal in step 801 receives and stores (in its memory) the following access priority system parameters broadcast by the base station: P which is the maximum number of preamble signatures (e.g. P <. 16); T which is the number of time shifts (for example T <8), so M is the total number (PxT) of logical access channels representing the number of processing units and the time search capabilities which includes the base station; and K ± which is the maximum number of retransmission attempts for each class i. Accordingly, in step 802, the remote terminal (by means of the processor associated therewith) determines whether a new access request is required due to the receipt of packets to be transmitted. If so, in step 804, the remote terminal selects a preamble from (1, ..., P). Then, in step 806, for class i, the remote terminal selects a time offset of (Ti7 ..., Ti ') so that T ± < Ti + 1 Ti +? / J-o - "/? E 8. For example, class 0 (highest priority class) can choose from a set of time shifts that they vary between offset 0 to time offset 4. In an alternative mode, the remote terminal may also store and then select a random chip delay at this point, according to the RCDAP solution in FIG. 5. Then the request for transmission is transmitted. access to the selected logical access channel, in step 808. Subsequently, in step 810, the terminal determines whether the access request has been received successfully by the base station. Again, this can be done by the base station transmitting a terminal access request acknowledgment message (step 1106 in FIG. 11). If the access request has been successful, then the access priority control method (block 812) ends and the remote terminal can transmit its packets according to the packet transfer scheme used in the UMTS. However, if the request is unsuccessful, in step 814, the terminal increments the variable no_tx by one. In step 816, no_tx is compared with Kx. If no_tx is greater than Ki r then the current access request is suspended (step 818). If the maximum number of retransmissions has not yet been reached, then the retraction process is performed in step 820. In an alternative embodiment, the retraction process is the same as that described above in step 618 of figure 6. After the retraction , the remote terminal waits, at step 822, for the next available access interval and then return to step 804 to repeat the process. Referring now to Figure 9, there is shown a flow chart of an access priority control method 900 in a remote terminal according to a fifth embodiment of the present invention. Again, it will be appreciated that this methodology is performed in a remote terminal (for example, terminal 2 or 4) which has generated or received packets to be linked up to a UMTS base station (for example station 6 of base) . The embodiment illustrated in Figure 9 is referred to below as the probability-based access priority (PBAP). Generally, in the PBAP solution, each subscriber is provided with an access priority class i. Each access priority class i can only transmit access requests with a certain probability Pi. Those with the highest priority (class 0) always transmit their access requests whenever there is a request for access. For example, P0 = 1 (high priority) and Px = 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. In the access priority mode in Figure 9, the remote terminal in step 901 receives and stores (in its memory) the following access priority system parameters broadcast by the base station: M which is the number of logical access channels which exist between the remote terminal and the base station; PL probability for each class i; and Ka, ex. which is the maximum number of transmission attempts associated with class I, where P¿ = 1 and P, < P1 + 1, K0 = K ^ y? X + 1 < K ±. Accordingly, in step 902, the remote terminal (by means of the processor associated therewith) determines whether a new access request is needed due to the receipt of packets to be transmitted. If so, in step 904, the remote terminal sets a variable no_tx = 0. This is the variable of retransmission attempts. Then, in step 906, the remote terminal determines whether x > (1 P) . It should be noted that x is a random variable uniformly distributed between 0 and 1. If x is not greater than (1-P ±), the remote terminal waits, at step 908, for the next available access interval and then returns to step 904 to repeat the process. If x > (1 - Pi), the remote terminal selects a logical access channel (1, ..., M). The access request is then transmitted on the selected logical access channel, in step 912. After, step 914, the terminal determines whether the access request has been successfully received by the base station. Again, this can be done by the base station that transmits a message of recognition of access request to the temporary one (step 1106 in figure 11). If the access request has been successful, then the access priority control method (block 916) ends and the remote terminal can transmit its packets according to the packet transfer scheme used in the UMTS. However, if the request has not been successful, in step 918, the terminal increments the variable no_tx by one. In step 920, no_tx is compared with Kx. If no_tx is greater than Kx, then the current access request is suspended (step 922). If the maximum number of retransmissions has not yet been reached, then the retraction process is performed in step 924. In an alternative embodiment, the retraction process is the same as that described before step 618 of figure 6. After the backward, the remote terminal waits, at step 908, for the next available access interval and then returns to step 904 to repeat the process. Referring now to Figure 10, there is shown a flow chart of a method 1000 for access priority control to a remote terminal according to a sixth embodiment of the present invention. It will be appreciated that this methodology is performed in a remote terminal (for example terminal 2 or 4) which has generated or received packets that are to be linked down to a UMTS base station (for example base station 6) . The modality illustrated in figure 10 it is referred to below as a retransmission-based access priority (REBAP). Generally, in the REBAP solution, the assumption is made that all access requests have an access packet priority (APP) associated with them. The REBAP scheme provides retransmitted access requests a higher priority with respect to new access requests. Such a feature is attractive for certain applications which require a smaller access delay of 95% or 99% or percentile for all successful attempts rather than a smaller average access delay. All new access requests are provided with the lowest APP class (nmax -1). Then, your priorities are dynamically adjusted based on the number of retransmissions. The access packets can have access to all of the logical access channels M but depending on the access packet priority class, they will choose a different random chip delay. The lowest APP class will have the highest average random chip delay distribution from which to make the selection. Those access requests that fail and that need to be retransmitted preferably have their APP class adjusted. Note that an access service priority (ASP) class can also be defined in addition to the APP feature. Those requests with the highest ASP, for example Class 0, will automatically increase your APP access requests failed with each retry. Those with the smaller ASPs will adjust the APP of their failed attempts less actively. For example, Class 1 ASPs may increase the APP of an access request only after they fail twice. In the priority mode. of access from Figure 10, the remote terminal in step 1001 receives and stores (in its memory) the following access priority system parameters broadcast by the base station: M which is the number of logical access channels the which exist between the remote terminal and the base station; APP which has, for each class i, two numbers associated with it, specifically Ki, which is the maximum number of retransmission attempts for each class i, RN1 # which represents the random chip delay for each class i. In addition, it is assumed that APP varies from 0, ..., nmax-l, where 0 has the highest priority. If ASP is used, then the ASP and S. parameters are also transmitted by the base station and received and stored by the remote terminal. Sj represents the number of retransmissions required for class j before the APPs of the access requests are updated, for that class j. Therefore, K? is related to the priority class APP and S. is related to the ASP priority class. For example, for ASP = 0, 1, 2; S0 = 1, Sx = 3, S2 = 5.

Accordingly, in step 1002, the remote terminal (by means of the processor associated therewith) determines whether a new access request is required due to the reception of packets to be transmitted. If so, in step 1004, the remote terminal sets APP = nmax-l, ASP = j, no_tx = 0 and adj = 0 (adj is explained later). Then, in step 1006, the remote terminal selects a random chip delay for distribution (KNX, ..., RNX '). In step 1008, the remote terminal selects a logical access channel (1, ..., M). The access request is then transmitted over the selected logical access channel in accordance with the chip delay, in step 1010. Then, in step 1012, the terminal determines whether the access request is successfully received by the subscriber station. base. This can be carried out by the base station transmitting a terminal access request acknowledgment message (step 1106 in FIG. 11). If the access request has been successful, then the access priority control method (block 1014) ends and the remote terminal can transmit its packets according to the packet transfer scheme used in the UMTS. 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 that an access request was transmitted by the remote terminal y- adj represents the variable used to verify if Sj has been reached. In step 1018, no_tx is compared with Ki. If no_tx is greater than or equal to K¿, then the current access request is suspended (block 1020). However, if no_tx is greater than or equal to K¿, then the remote terminal determines whether adj is greater than or equal to Sj (step 1022). In case this is not the case, APP remains the same as established in step 1004. Then, in step 1024, a back-off process is performed. The rollback process may be the same as that described in step 618 in FIG. 6. After kickback, the remote terminal waits, at step 1026, for the next available access interval and then returns to step 1006 to repeat the process . However, if adj is greater than or equal to Sj, then APP decreases by one (APP = n-l) whereby the priority of the retransmitted request is increased (step 1028). In addition, in step 1028, adj is reset to zero. Then, the rollback process is performed in step 1024. After rollback, the remote terminal waits, in step 1026, for the next available access interval and then returns to step 1006 to repeat the process. It will be appreciated that the use of the access priority methodologies of the invention, as described herein, may be useful and advantageous in various applications. The following are only some examples of such applications. In existing wireless access systems, It has not been provided in warnings to allow users who have an urgent need to gain access to a higher priority compared to other types of users. One possible implementation of access priority according to the invention is to reserve some logical access channels so that only emergency users can access them. In another scenario, a service provider may differentiate, according to the present invention, between different types of customers based on the service charges they pay. A CEO may wish to have a smaller access delay in order to achieve greater messages success through the network and to be faster in comparison with others. Preferably, this service is coupled with the service priority to ensure that users can perceive a better end-to-end delay. Furthermore, in order to provide a smaller access delay to some services in real time, for example interactive video, one can again use the access priority features of the invention to obtain this purpose. In addition, the present invention provides new access features that can be included in UMTS MAC. the access priority can be used together with protocol establishment algorithms to provide a different quality of service for clients either on the basis of in the service charges, emergency needs or delay requirements. Although the illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it should be understood that the invention is not limited to these precise embodiments, and that other changes and modifications may be made thereto. by those familiar with the technique without departing from the scope and spirit of the invention. For example, although certain variations of the embodiments illustrated in the flowcharts are described above, it will be appreciated that the present invention contemplates combining any modality, or variation thereof, with one or more embodiments or variations thereof.

Operation of the ODMAFO MAC protocol The operation of the total ODMAFQ MAC protocol is illustrated in the flow diagrams of Figures 12A and 12B. As seen from the remote host (terminal) figure 12A, after the setting of the power level for the upstream 1210 transmission, the remote guests participate in an initial uplink containment 1215 during which each remote unit with packets to send requests access to the AP (base station). If any of these access requests crash 1220, as long as they are sent in the same reservation mini-slot, remote guests who have crashed participate in a 1225 resolution of uplink conflict. Otherwise, the AP proceeds to allocate uplink bandwidth 1230 between remote hosts requesting access, followed by allocation of bandwidths for its own downlink 1235 transmission. Each remote host waits to receive a transmission 1237 permission during a subsequent downlink transmission and, upon receipt of one, transmits a waiting packet from its row. If the row on the remote unit is not empty then 1238, the remote unit returns to wait for an additional transmission 1237 permission, otherwise it waits for a new 1239 packet to arrive. As illustrated in Figure 12B, the AP monitors the activity in the containment reservation intervals 1260 received. When a successful access request 1265 is received, the AP sends 1270 reservation acknowledgments (ACK) and adds the new successful remote units to the 1275 protocol preparation list. Whether or not the access requests have been successful 1265, the AP also monitors the 1280 data intervals while the protocol preparation list is not empty, and when it receives a successfully transmitted 1285 packet, it responds with ACK 1290 data . The AP then elaborates a protocol of its packages 1240 downlink, allocates a protocol to the uplink transmissions 1245 of the remote hosts successfully contained, supplies the associated transmission 1250 permissions and then transmits downlink data packets 1255, after which it returns to monitor the activity in 1260 contention reservation intervals. It may be desirable to allow an optional channel retention feature whereby each row may remain empty for a short interval while it is without the release of the access point of the bandwidth reservation. This allows high priority users to stay at the base station or stations with the reserved bandwidth ready for an allocated amount of time before it is released, encouraging low latency of the packets in real time (ie, with little or no delay for sensitive data packets in time such as voice communications) by preventing all signaling messages from setting necessary for channel reservation. By using this feature, when a row is empty, a timer is activated in the wireless modem. As new packets arrive at the wireless modem before the timer expires, the wireless modem does not need to make a new access request. In the AP, if this feature is activated, then the AP will still assign a transmit permission for a data range for this particular wireless modem for each alternate uplink frame, even if the last uplink data transmission from the wireless modem has indicated that the row is empty. The AP will also start a timer. When the timer ends and the AP has not received new packets from the wireless modem, then the AP will remove the wireless modem from the list of reserved bandwidth. This channel retention feature is particularly useful if the bandwidth reservation process requires some time to complete, allowing low latency for real-time packets, which, while not queuing up, are not too far apart. so as to guarantee a reservation request for separate bandwidth by means of connection for each data packet. However, for download resources that do not need this channel retention feature, when a packet arrives to find an empty buffer, the modem will still send a request for access to the AP through one of the containment mini-slots. Figure 13A illustrates one embodiment of a method for access control. N containment reservation mini-slots are configured in each uplink 1310 frame. The N mini-slots are organized in a plurality of access priority classes, each class has one different priority. The AP is configured to allow N classes 1315 for access priority. Each remote host of access priority class i, takes 1320 randomly a containment mini-slot and transmits an access request, the contention mini-slot taken is in the range of 1 to N ± where N (i + 1) < N¡ and N¿ = N. The base station receives 1325 the access request and sequentially examines the received mini-containment intervals. If the mini-slot that is currently examined contains a request 130 that has not crashed, the AP grants access 1835 to the remote host corresponding to the access request that has not crashed. If the mini-slot that is currently being examined contains a 1330 request that has crashed, the AP will not send an ACK, which causes the affected remote nodes to carry out a conflict resolution 1340. After the conflict resolution period, the AP grants access to remote host 1345 A = winner. Meanwhile, if more mini-slots remain to be examined by 1350, the AP continues to verify mini-slots for 1330 collisions, granting access to 1335 guests with successful requests or waiting for the outcome of conflict resolution 1340. Figure 13B is a flow diagram illustrating an alternative embodiment of a method for access control. The N mini-slots are organized into a plurality of access priority classes, each with a different priority. The N containment reservation mini-slots are configured in an uplink 1310 frame. The N mini-slots are organized into a plurality of access priority classes, and each class has a different priority. The AP is configured to allow m classes 1315 of access priority. Each remote host of access priority class i and with a stacking level that is equal to 0, then transmits an access request with a probability P ^^ where P (i + 1) < Pi and Pi = 1 1360. The base station receives 1325 the access requests and sequentially examines the received mini-containment intervals. If the mini-slot that is currently being examined contains a 1330 request that has not crashed, the AP grants access 1335 to the remote host corresponding to an access request that has not crashed. If the mini-slot that is currently examined contains a 1330 request that has crashed, the AP will not send an ACK, which causes the affected remote nodes to make resolution 1340 of conflict. After the conflict resolution period, the AP grants access to host 1345 A remote winner. If more mini-slots remain to be examined by 1350, the AP continues to verify mini-slots for 1330 collisions, either by granting access to 1335 guests of successful requests or by awaiting the outcome of conflict resolution 1340.

The free status (IDLE), success (SUCCESS) and collision (COLLISION) information is transported back to the wireless modems. The AP places the interval status information in the downlink reservation acknowledgment field. There are three alternative, preferred conflict resolution methods that can be used. The first method is suggested in the IEEE 802.14 standard and is described along with two new methods below. The simulation of results shows that the second method described provides the minimum access delay. In the first method of conflict resolution, suggested in IEEE standard 802.14, each wireless node that wishes to transmit takes one of the mini reservation slots randomly, if a collision is indicated, a modem that is affected by the solution retransmits based on a method of random exponential binary regression. This method of recoil operates according to the following: The modem generates a random number I, evenly distributed between 0 and 2j - 1, where j is the number of collisions that a modem has experienced for the packet that it tries to transmit. If j is greater than 10, then I is selected from a uniform distribution between 0 and 210 -1.

The modem jumps to the next 1-1 contention interval opportunity of the same class (either mini-slot or data contention interval) and transmits its previously crashed packet at the next immediate contention interval opportunity.

The operation of this method is found in Figure 14A. A wireless node waiting for access in the AP takes 1402 randomly a reservation mini-slot in which to transmit an access request. If the node is affected by a collision 1404, the node generates 1408 a random number I and jumps 1410 to the next contention interval opportunity 1-1 of the same class. The node that retransmits 1412 the access request for the packet crashed at the next immediate contention interval opportunity. If the node is not affected by the shock 1404, then if the row in the node is empty 1405, the node transmits the packet to 1406 and returns to the wait state 1402. If the row in the node is not empty 1405, then, after receiving a transmission permission from the AP, the node transmits to 1407 the current packet together with the reservation request placed in cascade for transmission of the next packet in its row, continuing to transmit packets with reservation requests 1407 placed in cascade after receiving transmission permissions until the row is empty 1405 and the final packet 1406 has been transmitted, after which the node returns to wait state 1402. In the second and third methods, the AP broadcasts the result of each contention in the reservation mini-slots to all the wireless nodes by means of a downlink broadcast message. In the second method, the modem in each wireless node is characterized by a stacking level, and only wireless access request packets with a stacking level equal to zero are allowed to transmit. Modems with a stacking level greater than zero are considered as being in preparation. For example, when there are M reservation mini-slots, each remote node with a stacking level 0 can randomly take one of the mini-slots M. At the end of a mini slit, the wireless i node changes the stack level based on the result of a transmission in the time interval. This method allows the recent active wireless nodes to join existing wireless nodes that have a stacking level of 0 during a particular conflict resolution period. Each wireless node in a request state increases its stacking level by one if it does not transmit an access request packet and receives a negative acknowledgment (eg, that there has been a crash) from the base station (AP). For other In part, a wireless node decreases its stacking level by one if it receives a positive acknowledgment from the base station, which indicates a successful transmission of an access request. Each wireless node participating in the random access request transmission A coin flip * to determine if the stacking level remains at level 0 or if it increases upon receipt of a negative acknowledgment from the base station. The rules of the second method are: 1. When the wireless node first wants to access the network or has gained access and wants. send new data, it is placed in a request state and assigned a stacking level of zero. 2. When there are M reservation mini-slots, each wireless node in a request state randomly takes one of the reservation mini-slots M, which is an assigned mini-slot in which to transmit an access request packet. 3. When the wireless node is characterized by an access level equal to zero, it transmits an access request packet; However, when the remote node is characterized by a stacking level different from zero, does not transmit an access request packet. At the end of the time interval, each wireless node changes its stacking level based on the result (ie, CHECKED (COLLIDED), FREE (IDLE), or SUCCESS) of an access request, as reported by its mini-slot assigned in the reservation recognition field of a message of downlink from the access point. A. A wireless node that sends an access request and receives a SUCCESS result will be removed from the request status. 15 B. A wireless node that sends an access request and receives a result of COLLIDED will increase its stacking level by one or will leave its stacking level at zero, depending of the result of a random extraction. C. A wireless node that is in the request state and does not send a request for access (ie, a node in preparation with a stacking level > 0) will increase your stacking level by one if the result reported in the reservation recognition field for the assigned mini-slot is CHOCKED (COLLIDED). D. A wireless node that is in the request state and does not send a request for - access (ie, a node in preparation with a stacking level> 0) will decrease its stacking level by one if the reported result in the reservation recognition field for the assigned mini-slot is SUCCESS.

The operation of this method is shown in Figure 14B. A wireless node that expects to access the AP or send new 1432 data sets its stacking level to 0 and enters the request status. If the stacking level at the node is 0 1434, the node randomly takes 1436 a reservation mini-slot for transmission of an access request and transmits the access request. If the result of the request is SUCCESS 1438, and the row of the node is empty 1439, the node transmits 1440 the current packet and leaves the request state, returning to the state 1432 waiting. If the row in the node is not empty 1439, then, after receiving a transmission permission from the AP, the node transmits 1441 the current packet together with a reservation placed in cascade for transmission of the next packet in its row, continuing to transmit packets with cascading reservation requests 1441 after receiving transmission permissions until the row is empty 1439, at which point it transmits the remaining packet 1440, and exits the request state and returns to waiting state 1402. If the result of reservation request 1436 is not SUCCESS 1438, the node participates in a random 1444 extraction to learn if it increases 1448 its stacking level by one or if it abandons 1446 its stacking level by 0. If it remains 1446 the level of stacking at 0, the node again takes 1436 randomly a reservation mini-slot for transmission of an access request and transmits the access request. If stacking level 1448 is increased, the stacking level will not be 0 1434. If the stacking level of any remote node is not 0 1434, then if the result of the pre-booking request is SCAM (COLLIDED) 1450, the node increases its stacking level by 1452 by 1. If the result for the pre-order request is not SHOCKED (COLLIDED) 1450, the node decreases 1454 its stacking level by 1.

The third method of conflict resolution is a modification of the second. In the third method of conflict resolution, the modem in each wireless node is again characterized by a stacking level, and only wireless nodes with a stacking level equal to zero are allowed to transmit access request packets. Modes with a stacking level greater than zero are considered as being in preparation. The rules of the third method are: 1. When the wireless node first wants access to the network or has gained access and wants to send new data, it is placed in a request state and assigned a zero stacking level. 2. When there are M reservation mini-slots, each wireless node in a request state randomly takes one of the reservation mini-slots M, which is an assigned mini-slot in which to transmit an access request packet. 3. When the wireless node is characterized by a stacking level equal to zero, it transmits an access request packet; however, when the remote node is characterized by a non-zero stacking level, it does not transmit an access request packet.

At the end of the time interval, each wireless node transmits its stacking level based on the result (ie, CHECKED (COLLIDED), FREE (IDLE) OR SUCCESS) of all access requests, as reported in the reservation recognition fields of a downlink message from the access point A. A wireless node sending a access request and that receives a result of SUCCESS will be removed from the request status. B. A wireless node that sends an access request and receives a result of CHOCADO (COLLIDED) will increase your stacking level by one or will leave your stacking level at zero, depending on the result of a random extraction. C. A wireless node that is in a wait state and does not send an access request (that is, a node in preparation with a stacking level> 0) will decrease its stacking level in one if the results of all the access requests reported in at least 80% (or other predefined threshold) of the reservation recognition fields is SUCCESS (SUCCESS) or free (IDLE). Otherwise, the remote node will increase its stacking level by one. D. When the modem in preparation equal to the stacking level is decremented to zero, the modem randomly takes one of the M mini-slots (or the mini-slot if the access priority is implemented) to resend its request. The operation of this method is shown in Figure 14C and is similar to that of the method of Figure 14B. A wireless node that expects access to the AP or that sends new 1432 data sets its stacking level to 0 and enters the request status. If the stacking level of the node is 0 1434, the node takes 1436 randomly a reservation mini-slot for transmission of an access request and transmits the access request. If the result of the request is SUCCESS 1438, and the row in the node is empty 1439, the node transmits 1440 the current packet and leaves the request state, returning to wait state 1432. Yes the row in the node is not empty 1439 then, after receiving a transmission permission from the AP, the node transmits 1441 the current packet together with the reservation request placed in cascade for transmission of the next packet in its row, and continues transmitting packets with the reservation requests 1441 cascaded after receiving transmission permissions until the row is empty 1439 and the remaining packet 1440 has been transmitted, after which it exits the request state and returns to wait state 1402. If the result of reservation request 1436 is not SUCCESS 1438, the node participates in a random extraction 1444 to learn if it increases 1484 its stacking level by 1 or if it leaves 1446 its stacking level by 0. If the level of stacking remains 1446 at 0, the node again takes 1436 randomly a reservation mini-slot for transmission of an access request and transmits the access request. If the stacking level is increased 1448, the stacking level will not be 0 1434. If the stacking level of any remote node is not 0 1433, then if the result of all the reservation requests during the previous cycle is CHOCKED (COLLIDED ) 1460 for more than or equal to a certain THRESHOLD percentage, the node increases 1462 its stacking level by 1. If the result of the previous reservation request is not crashed (COLLIDED) 1460, the node decreases 1464 its level of stacking in 1. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the one that is clear from this description of the invention.

Claims (2)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A method of access priority control in a remote terminal of a wireless communication system, the method is characterized in that it comprises the steps of: selecting a chip delay to be associated with an access request signal from among different chip delays selectively associated with pre-established access priority classes, and transmitting the access request signal over a selected logical access channel to a base station in a wireless communication system.
2. 2. The method according to claim 1, characterized in that a higher access priority class is associated with a lower chip delay. The method according to claim 1, characterized in that the lower access priority class is associated with a higher chip delay. 4. The method according to claim 1, characterized in that it further comprises the step of determining if the access request signal has been received by the base station. The method according to claim 4, characterized in that the determination step includes monitoring to determine the reception of a recognition signal from the base station indicating the reception of an access request signal. The method according to claim 4, characterized in that it also includes the step of increasing a variable indicative of the number of attempts to transmit the access request made to the base station when the determination step indicates that it has not been received by the base station the preceding access request signal. The method according to claim 6, characterized in that it further includes the step of comparing the attempt to transmit intent transmission variable to a value indicative of a maximum permissible number of transmission attempts, the allowable transmission attempt value maximum is a function of the pre-established access priority classes. 8. The method according to claim 7, characterized further includes the step of suspend the access request when the access request transmission attempt variable is greater than the maximum permissible transmission attempt value. The method according to claim 8, characterized in that the step of performing a backward process is also performed when the access request transmission attempt variable is no greater than the maximum permissible transmission attempt value. The method according to claim 9, characterized in that it further comprises the step of repeating the chip delay selection step and the transmission step, after the retraction process, in order to transmit another access request. The method according to claim 1, characterized the pre-established access priority class is related to one of service level, message content and delay requirements. 12. The method according to claim 1, further comprising the step of receiving the chip backward delays from the base station. 13. The method according to claim 1, characterized the chip delays are associated with random distributions of backward chip delays which are respectively associated with pre-established access priority classes and the chip delay is associated with an access request signal and selected from one of the distributions. The method according to claim 1, characterized further includes the step of selecting the logical access channel for transmission from among a set of logical access channels, the set includes a number of logical access channels, the quantities of a function of the pre-established access priority classes. The method according to claim 1, characterized in that it further includes the step of selecting the logical access channel for transmission by selecting a preamble and a time offset from a set of preambles of a set of time offsets associated with a plurality of logical access channels. The method according to claim 15, characterized in that the time shifts without a function of the pre-established access priority classes. 17. The method according to claim 1, characterized in that the wireless communication system is a UMTS. 18. The method according to claim 1, characterized in that the selected logical access channel is an RACH. 19. An access priority control method in a base station of a wireless communication system, the method is characterized in that it comprises the steps of: broadcasting chip delays associated respectively with pre-established access priority classes; and transmitting a recognition signal to a remote terminal in the wireless communication system from which an access request signal having a chip delay associated therewith has been received. 19. An apparatus for access priority control in a wireless communication system, characterized in that it comprises: a remote terminal configured to select a chip delay that is associated with the access request signal of different chip delays associated respectively with the pre-established access priority classes and for transmitting the access request signal on a selected logical access channel to a base station in the wireless communication system. 21. The apparatus according to claim 20, characterized in that the remote terminal is a mobile terminal. 22. The apparatus according to claim 20, characterized in that the. Remote terminal is a fixed terminal. 23. The apparatus according to claim 20, characterized in that a higher access priority class is associated with a lower chip delay. 24. The apparatus according to claim 20, characterized in that a lower access priority class is associated with a higher chip delay. 25. The apparatus according to claim 20, characterized in that the remote terminal determines whether the access request signal has been received by the base station. 26. The apparatus according to claim 25, characterized in that the remote terminal performs the step of determining by monitoring for the reception of a recognition signal from the base station indicating the reception of the access request signal. 27. The apparatus according to claim 25, characterized in that the remote terminal increases a variable indicative of the number of attempts of transmission of access request made to the base station when the determination step indicates that the preceding access request signal has not been received by the base station. 28. The apparatus according to claim 27, further characterized in that the remote terminal compares the variable access request transmission attempt to a value indicative of a maximum permissible number of transmission attempts, the maximum permissible transmission attempt value is a function of the pre-established access priority classes. 29. The apparatus according to claim 28, further characterized in that the remote terminal suspends the access request when the access request transmission attempt variable is greater than the maximum permissible transmission attempt value. 30. The apparatus according to claim 29, further characterized in that the remote terminal performs a backward process when the access request transmission intent variable is no greater than the maximum permissible transmission attempt value. 31. The apparatus according to claim 30, characterized in that the remote terminal repeats the step of chip delay selection and the step of transmission, after the backward process, in order to transmit another access request. 32. The apparatus according to claim 20, characterized in that the pre-established access priority classes are related, with a service level, message content and delay requirements. 33. The apparatus according to claim 20, further characterized in that the remote terminal receives the chip delays from the base station. 34. The apparatus according to claim 20, characterized in that the chip delays are associated with random distributions of the chip delays which are respectively associated with the pre-established access priority classes and the chip delay to be associated. with the access request signal is selected from one of the distributions. 35. The apparatus according to claim 20, further characterized in that the remote terminal selects the logical access channel for transmission from among a set of logical access channels, the set includes a number of logical access channels, the amount is one function of pre-established access priority classes. 36. The apparatus according to claim 20, further characterized in that the terminal remote selects the logical access channel for transmission by selecting a preamble and a time offset from a set of preambles and a set of time offsets associated with a plurality of logical access channels. 37. The apparatus according to claim 36, characterized in that the set of time shifts are a function of the pre-established access priority classes. 38. The apparatus according to claim 20, characterized in that the wireless communication system is a UMTS. 39. The apparatus according to claim 20, characterized in that the selected logical access channel is an RACH. 40. An apparatus for access priority control in a wireless communication system, characterized in that it comprises: a base station configured to broadcast chip delays associated respectively with pre-established access priority classes and to transmit a recognition signal to a remote terminal in a wireless communication system from which an access request signal having received has been received. a chip delay associated with it.