低轨卫星通信系统中的一种呼叫接入控制策略

对于低轨卫星通信系统(LE0)的每个小区来说，随时都有大量的新呼叫切换呼叫到达，并要求在本小区内分配有限的信道资源进行通信。这就需要一种呼叫接入算法具有优化系统性能，改善呼叫阻塞率和信道利用率等参数，因此提出了一种呼叫接入控制算法PGC(part guard channels)，即部分接入算法，此算法除吸取传统的预留信道GC(guard channels)算法已有的优点外，还进行了一些改进，使系统的新呼叫阻塞率和切换呼叫掉话率得到了更好的平衡，在分析GC和PGC的几种子算法的基础上，进行计算机仿真，并给出了相应的仿真结果，最后在服务等级、信道占用率等重要参数方面对2种算法进行了对比分析。

A call admission control algorithm for LEO systems

Because of the frequent arrivals of new and handover call requests and limited channel resource in Low Earth Orbit (LEO) satellite system, it's necessary to adopt a call admission control(CAC) algorithm to avoid the call blockings, especially the handover call dropping probability. In this paper, a PGC scheme, which means part guard channels algorithm is introduced on the basis of traditional guard channel algorithm and keeps the better blocking probability and dropping probability on balance. Properties of the two algorithms are studied in some important aspects. Finally, computer simulation results are given and analyzed.