拥塞控制卫星PRMA-AC协议及性能分析

Performance of PRMA-AC:A Congestion Control PRMA Protocol for Satellite Communication

卫星通信中PRMA协议在负荷较重时由于终端竞争加剧会引起信道拥塞,而较长的传播时延更进一步加剧了拥塞引起的丢包。该文提出一种利用话音终端在通话的不同阶段对信道资源的不同需求对终端进行区分的方案PRMA-AC,据此引入一种接入控制机制,以减少信道竞争,提高系统服务质量。文中给出了系统模型,对协议性能进行了理论分析,获得了新协议下的接入阻塞率、丢包率等性能指标,最后通过仿真与几种卫星通信中常用的PRMA协议进行了对比,证明了协议的性能。

There is problem of channel congestion caused by the increased channel contention in satellite communication system with Packet Reservation Multiple Access （PRMA） protocol when the payload （amount of user terminals） goes up, and the long propagation delay worsens the situation with the result of increased packet drop rate. Considering that the requirement of the voice terminal for channel resource in different phase of communication progress is different, a new scheme of PRMA named PRMA-AC is proposed, which aims to decrease the channel contention and improve the quality of service by adopting an access control mechanism. Through theoretic analysis, the system model of the new scheme is given and performance parameters such as the access block probability and the packet drop probability are obtained. Finally, the scheme is compared with several other satellite PRMA protocols by simulation, and the result validates that the scheme is effective.