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针对在随机接入中由于碰撞导致吞吐率低、信道拥塞时不能满足高优先级数据有效传输的问题,提出一种具有不等差错保护性能的多用户随机接入方法。该方法将数据包复制多份,根据选定的度分布在不同时隙中传输,将随机接入过程映射到二分图上;接收端利用连续干扰消除技术(SIC),将碰撞的数据包恢复出来。在高链路负载下,从每帧中选取若干时隙,只允许高优先级用户接入,以提高对高优先级数据包的译码概率。使用“与或树”理论对提出的方法进行了理论分析,并进行了实验仿真验证。仿真结果表明:提出的多用户随机接入方法与传统ALOHA协议相比,在低链路负载下有效避免由于碰撞引起的吞吐率下降;与IRSA协议相比,高链路负载下有效提高高优先级用户的吞吐率。
Aiming at the problem of low throughput and poor congestion in high-priority data transmission due to collision in random access, a multi-user random access method with unequal error protection is proposed. In this method, data packets are duplicated and transmitted in different time slots according to the selected degrees of distribution, and the random access process is mapped to the bipartite graph. The receiver uses continuous interference cancellation (SIC) to recover collided packets come out. Under the high link load, several time slots are selected from each frame, and only high-priority users are allowed to access to improve the decoding probability of high-priority data packets. The theory of “and or tree” is used to analyze the proposed method, and the experimental simulation is carried out. The simulation results show that the proposed multi-user random access method can effectively avoid the drop of throughput caused by collision under the condition of low link load compared with the traditional ALOHA protocol. Compared with the IRSA protocol, the effective increase of high priority under the high link load Level user throughput.