基于随机Petri网的GSM-R双层网络建模与性能分析

利用随机Petri网,综合信道降质、链路中断、越区切换、灾害等因素,建立GSM-R的同站址网络与交织站址网络的故障模型,针对同站址与交织站址两种不同的网络结构,给出利用马尔可夫链求解可靠性与可用性的方法。通过马尔可夫链的有关概率分别计算:不同网络结构的可靠性;不同列车运行速度对应不同网络结构的可用性。分析计算结果表明:同站址网络的可靠性与可用性远高于交织站址网络,主要原因是同站址网络中一层基站业务中断时不会导致系统失效,交织站址网络中一层基站业务中断时,并联的另一层相邻两个基站均可以提供业务才不会导致系统失效。另外,同站址网络中越区切换速率较小,有效减小了列车越区切换对可靠性与可用性的影响。

Modeling of GSM-R Double-level Network and Its Reliability Analysis Based on Stochastic Petri Net

On the basis of the stochastic Petri net,the failure models of the co-site GSM-R network and intercross GSM-R network are developed,which capture the failure factors such as channel transmission errors,connection losses,and handovers,etc..Separate solutions to the reliability and usability of these two different net structures are given.Making use of the relative probabilities of the Markov chain,the reliability of different configurations of the GSM-R network and the applicability of different configurations of the GSM-R network in train operation at different velocities are calculated.The results show as follows: The reliability and usability of the co-site network is far higher than that of the intercross network;the main reason is that the system of the co-site network will not fail in case of interruption of one.Base Transceiver Station(BTS) at one level however,in the intercross network,when one BTS at one level fails,the whole system will not fail only when both the two adjacent BTSs at another parallel level do not fail;in addition,the rate of handover is lower in the co-site network,which can efficiently reduce the impact of handover on the reliability and usability of the co-site network.