一种不等差错保护的多用户随机接入方法

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(SIC)技术,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。

A random multi-user access method with unequal protection

The throughput performance degrades under high traffic loads when massive bursty users have access to the satellite.To solve this problem,a random multi-user access method with unequal protection was proposed.Several copies of a packet were created and sent during different time slots according to a selected degree distribution.The random access procedure could be described by a bipartite graph.By using successive interference cancellation (SIC),collided packets can be recovered instead of abandoned.In addition,a portion of time slots in each frame were selected exclusively for high-priority users to improve the decoding probability of high-priority data packet.An analysis using standard "and-or trees" theory was introduced.Further,the proposed method was verified with experimental simulations.The simulation results show that the proposed random multi-user access method,compared with traditional ALOHA protocol,effectively avoids the throughput degradation caused by impact under low traffic loads.Compared with IRSA protocol,it enhances high-priority users' throughput under high traffic loads.