高空平台通信系统中重叠区辅助切换保证策略

摘要

为了确保高空平台通信系统提供通信业务的连续性,提出重叠区辅助切换保证策略(GHS-OA).该策略在连接允许控制决策过程中,除利用高空平台和用户位置信息之外,还利用蜂窝之间的重叠区来协助判定并阻塞可能引起切换失败的新呼叫.建立多业务条件下基于时间的信道预留算法(TCRA)和GHS-OA的分析模型,推导上述2种策略在2类业务条件下新呼叫阻塞性能的数值解.通过仿真验证分析模型的有效性,与TCRA相比,在2类业务条件下GHS-OA可以极大地提升新呼叫阻塞性能,同时能够获得零切换掉话率,重叠区比例越大,利用重叠区的信道资源越多,GHS-OA的新呼叫阻塞性能越好.%To guarantee the service continuity provided by HAP communications systems, overlap area assisted guaranteed handover scheme (GHS-OA) was proposed. In the connection admission control process of this scheme, overlap areas between cells in addition to the position information of the HAP and the users were utilized to decide and block the new call which might introduce a handover failure. The analytical model was established for time based channel reservation algorithm (TCRA) and GHS-OA. The numerical solutions for two kinds of service were derived to analyze the new call blocking performance of these two schemes. Simulation results verify the analytical model. Research results show that the GHS-OA can improve the new call blocking probability significantly while maintaining a zero handoff call dropping probability seen with the TCRA, and that the bigger the overlap ratio and the more number of channel resources are considered in the overlap area of a virtual cell, the better the new call blocking performance that the GHS-OA can achieve.