Scheme for packet allocation in a radiocommunication system

[0001] The present invention relates to a telecommunications system that uses packet transmission and wireless communication transfer. More specifically, the present invention relates to a method of allocating incoming packets from packet transmission within a limited time slot in a wireless communication system. [0002] In a transmission system intended to provide two-way services, it is extremely important to specify the strict quality of services required for communication. Since these services are tied to the time response of all systems, their time delays must be optimized to ensure the quality of this service. It is known that no time delay is perceived when the system response time is below the limit specified by the type of service required. For example, telephone communications have a limit of about 400 milliseconds, while medical remote systems have a limit of 5 milliseconds. Therefore, the time delay due to the system itself is extremely important. [0003] In telecommunications and wireless communication systems, the bit error rate (BER), which measures the quality of transmission, can be improved by using error correction codes. In packet (or cell) transmission, this correction code can be used in two ways. That is, individual packet coding or group coding with packet interleaving. This interleaving method allows the reduction of the signal-to-noise ratio (SNR) threshold required to reach the required BER. This method, on the other hand, has to wait for the entire interleaved packet group to be decrypted. [0004] In U.S. Pat. No. 5,231,633, queuing and dequeuing for use in an integrated high-speed packet network in which high-speed packets from different traffic types are multiplexed through the use of a weighted round-robin bandwidth allocation mechanism. ) Mechanism is disclosed. Fast packets within a particular traffic type are selected for transmission through the use of the Head of Line Priority Service (514), the packet drop mechanism, or both. The weighted round robin bandwidth allocation mechanism works in part based on the credit counters of each queue group indicating a particular traffic type. [0005] U.S. Pat. No. 5,905,730 discloses a packet scheduler that provides a high degree of fairness in scheduling packets for different sessions. Similarly, this scheduler minimizes packet delays for packets from multiple sessions that may have different requirements and may operate at different transmission rates. When a packet is received by the scheduler, the packet is the packet parenchyma of the packet itself, based on whether the session has any pending packets and the values of the actual end time and packet arrival time of the preceding packet for that session. Assigned a start time. The scheduler then determines the actual end time of the packet by determining the transfer time required for the packet based on the length and speed of the packet, and by adding the transfer time to the actual packet start time of the packet. .. A packet with the minimum real end time is then scheduled for forwarding. By selecting packets for transmission in the method described above, the available bandwidth can be divided into proportions proportional to the guaranteed session speed, which provides a high degree of fairness to the scheduler, while Also minimizes the total amount of time a packet waits in the scheduler before it is sent. [0006] In US Pat. No. 5,917,822, the method according to the invention allocates bandwidth fairly and dynamically in a shared media packet-switched network for accommodating both elastic and inelastic applications. Performed by or within the headend controller, this method translates a request for bandwidth into a real scheduling time in order to allocate a bandwidth transmission slot and grant access to shared media. This method can use a weighted fair wait algorithm or a real clock algorithm to generate a sequence of upstream slot / transmission allocation permits. This method addresses a diverse class of quality of service (QoS) through a mechanism that gives the highest priority to the class of service with the strictest QoS requirements. [0007] These systems provide a certain quality of service and enable faster packet transmission, but do not take into account the characteristics of the terminal. These are not suitable for telecommunications systems with limited power performance, which is one of the problems solved by the present invention. [0008] Communication with terminals is sporadic in code division multiple access (CDMA), time division multiple access (TDMA), or frequency division multiple access (FDMA) systems that use packet transmission, such as asynchronous transfer mode (ATM). Can be the target. The power required to enable transmission to the terminal is adjusted according to the propagation conditions. These accesses lead to statistical multiplexing in the passband and in the power controlled by the filling algorithm. Interleaved coding results in increased time transfer of packets at a given terminal, which is unacceptable when good quality of service is required. [0009] Resource allocation can be difficult for interleaved coding for the following reasons: [0010] Quality of service is especially needed for packet forwarding. [0011] The power is the same for packets that belong to the same group. [0012] The system must optimize its power and bandwidth consumption and eliminate supplemental or introductory packets. [0013] To solve these problems, it is possible to use packet interleaving in single or multiple terminals, deductive or inductive packet selection, fixed or variable position of interleaved packet frames, i.e. a suitable carrier filling algorithm. .. [0014] The first method for defining classes is based on a deductive knowledge of radiated power for each terminal, independent of the allocation process. At the end of the allocation, the packet is interleaved in a cluster with the same length as the interleave. [0015] The second method builds a post-assignment class, which corresponds to the optimal inductive class convention. Power class losses are minimized. Additional loss may occur when the number of packets allocated is not a multiple of the interleaved length. [0016] It is known that a single terminal requires a sufficient number of packets to be transmitted for efficient coding within a limited time. The two methods are combined depending on the number of packets being encoded. The default method is to interleave unless the number of packets is too small. In this case, another coding method is used. This solution is not very efficient and requires two decoders in the terminal. [0017] The present invention is a method of allocating a packet to a carrier wave including a time slot, which includes a step of defining an interleave length and an allocation window, and the packet is allocated within a group defined by the power required for transmission. , And the size of the group is at most equal to the interleaved length. [0018] Packets may come in from different terminals during the allocation process. [0019] To minimize power loss within a group, packets are sorted according to the power of the packet during allocation and spread within the group according to the sort order. The sorting algorithm can minimize the overall power loss during allocation. [0020] In a preferred embodiment, the packets are interleaved into at least one group. [0021] [0021] This method can be used in TDMA systems, CDMA systems, or FDMA systems. [0022] The present invention also relates to packet transmission receivers, such as ATM receivers, which also include storage and computing means for using this method. [0023] The present invention relates to multiple terminals that use power class clustering. The power class allows packet interleaving with clustering of packets with adjacent radiated power. Power loss due to packet grouping is minimized because the interleaved packets are transmitted at the lowest available power terminal. [0024] Figure 1 shows the interleaving of four packets. The power required for transmission (1) corresponds to the most powered packet (10). Other packets are less powered and therefore lose some of their radiated power (2). An object of the present invention is to find a packet with power close enough to minimize this loss. [0025] Figure 2 shows a general method of carrier load algorithm (CLA) (6). Different packets come in at random (3). These packets are recognized according to their Skybridge terminal (SKT) and their power (4). The CLA also requires two variables that define the quality of service. The first variable, commonly known as bandwidth (Nmax), gives the number of packets allowed in one time slot (TS). The second variable gives the rules of power specified to avoid interference with other systems. This corresponds to the variable Pmax. The CLA must fill the carrier with respect to these two restrictions, as in (5). [0026] FIG. 3 shows the filling algorithm itself. The first seven packets are already on the carrier in Figure 3a. The next step is. It consists of placing packet number 8 between packets 6 and 4 in order of decreasing power (Figure 3b). [0027] The present invention comprises grouping packets with adjacent powers to fill a carrier wave and to enable interleaved coding. Each group corresponds to a power class, and its packet number is the same as the interleave length. [0028] In a preferred embodiment, a particular algorithm uses this method to fill the carrier in the most efficient way. [0029] When they are received, the ATM packets are sorted into four queues based on the quality of the associated connection. These queues include packets from all terminals assigned to the carrier. [0030] In this embodiment, the algorithm has four time slot allocation cycles and allocates with respect to: [0031] The total number of codes available. [0032] The total power available to fill the carrier. [0033] Power difference between cords in the same time slot. If these powers are too different, the code with the lowest power may be lost due to the noise of the code with the highest power. [0034] At each stage, the algorithm starts by selecting the packets that require the most important quality of service, and then gradually spreads them over the first available time slot in the allocation window. , Sort them in ascending order of power. [0035] Therefore, the first code in the first time slot contains the most powerful packet. When the algorithm decides to put the packet in the carrier, when the packet can be inserted, the packet looks for the code and time slot. If inserts are possible, all packets with less power will be shifted. [0036] At the end of the allocation process, the power class corresponds to the power required to carry the packet on four time slots on one code. Therefore, this power class configuration is dynamically done in the allocation process. [0037] Since this method only systematizes a method of placing a packet on a carrier wave independently of the transfer mode, it can be applied to any kind of queue, such as Weighted Fair Queuing. This method is a complementary process between the scheduler and the telecommunications mode. [0038] It has been measured that in interleaving four packets, the SNR required to guarantee a given packet loss rate is reduced by 1 dB compared to single packet coding. Conversely, there is a loss due to clustering that is expected to be 0.3 dB, which results in an overall gain of 0.7 dB in the system. [Simple explanation of drawings] FIG. 1 is a diagram showing four packet interleaves. FIG. 2 is a diagram showing a general method of the carrier load algorithm (CLA) (6). FIG. 3A is a diagram showing the filling algorithm itself. FIG. 3B is a diagram showing the filling algorithm itself.