考虑38 GHz毫米波通信中断与信道占用因素,依据磁浮运控系统越区切换流程建立了确定与随机Petri网(DSPN)模型,对单一移动终端(MT)和冗余MT两种结构进行了比较,研究了基站间距和列车运行速度对单一MT和冗余MT两种结构越区切换可靠性的影响。研究结果表明:冗余MT越区切换性能明显优于单一 MT,后者的停车概率约为前者的3×104倍;越区切换成功率随列车运行速度的提高而降低,随基站间距的减小而降低;在极端情况下,即列车以500 km·h-1运行,且相邻基站间距为500 m,冗余 MT 和单一 MT 越区切换成功率只有98.50%和97.85%。研究结论为磁浮运控系统车地通信子系统的服务质量优化与移动小区设置提供了依据。
Considering the factors of the communication outage of 38 GHz millimeter wave and channel occupancy,deterministic and stochastic Petri nets model (DSPN)was developed based on the handoff process of maglev operation control system. The structures of single mobile terminal (MT ) and redundant MT were compared.The effects of base station interval and train running velocity on the handoff reliabilities of single MT and redundant MT were investigated.Investigation result indicates that the handoff performance of redundant MT is significantly higher than that of single MT,the parking probability of single MT is approximate 3×104 times of that of redundant MT.The handoff success rate reduces with the increase of train running velocity and the decrease of base station interval.In the special case,in which the train running velocity is 500 km·h-1 and the base station interval is 500 m,the handoff success rates of redundant MT and single MT are only 98. 50% and 97. 85% respectively. Research result provides basis for the QoS optimization of train-ground communication subsystem in maglev operation control system and mobile cell setting.3 tabs,7 figs,19 refs.