GSM—R系统中通知响应过程的改进与设计

Improvement and Design for the Process of Notification Response in GSM-R System

GSM—R协议中的延迟指配方案对组呼信道进行动态管理,系统在组呼小区没有用户时不分配信道,由MS发起通知响应请求,触发系统分配组呼信道以加入呼叫。该方案存在的问题是:多个移动台同时发起通知响应时,部分MS响应失败,无法及时直接加入呼叫。为此提出分别在MSC,MS侧修改通知响应过程的2种改进措施:在MSC侧,以FIFO方式延迟处理重复的通知响应,当1个通知响应过程成功分配信道后,同一小区其他通知响应均按失败处理,并通知发起通知响应的MS新分配组呼信道信息,以便其加入呼叫;在MS侧,当重复通知响应失败后,MS不立刻进入空闲状态,而是在固定时限内监听通知信道,在发现系统分配了该组的呼叫信道时MS自动加入呼叫,从而使通知响应失败的MS也能够成功加入呼叫。

In delay assignment of GSM-R system, TCH channels are dynamically assigned. TCHs are not assigned in the group cells without any user, and MSs could apply for TCH by notification response to join the call. But there may be a problem that many MSs could not automatically join the group call in the case of multi MSs sending notification response simultaneously. Two measures were provided to let the notification response failed MS join the group call. One is to delay the handling of reduplicated notification response by fist in first out in MSC. When some notification response is succeeded, MSC reject the other no- tification response and tell the related MSs the newly assigned group channel information so that the MSs could join the group call. Another is to let MS listen to the NCH instead of going to idle mode after failed in notification response process and try to join the newly assigned group channel in some time.