一种新的基于多业务的移动通信系统切换策略

A novel handoff strategy based on multi-service in mobile communication systems

针对目前移动通信系统大部分信道切换策略中新呼叫阻塞率高的问题,提出了一种新的呼叫延迟切换策略,该策略是让即将占用最后一个空闲信道的新呼叫短暂延迟后再占用空闲信道,切换呼叫则直接占用空闲信道,缩短了信道被全部占用的时间,增加了新呼叫和切换呼叫占用信道的机会。该策略同时考虑了数据业务之间的优先级,只有当高优先级数据队列中的数据包为空时,低优先级队列中的数据包才能够占用信道。给出了切换呼叫掉话率、新呼叫阻塞率及数据包掉包率的理论公式。与预留信道策略和可移动边界策略的对比表明,新策略既提高了新呼叫进入系统的概率,又有效降低了切换呼叫的掉话率,同时也减少了高优先级数据的掉包率。

Aiming at the problem of high blocking probability in many handoff strategies, a novel handoff strategy is proposed to improve the performance of mobile communication systems by adopting some delay to the new calls over the handoff calls when there exists one idle channel. The time is shortened in the busy state. The opportunities of the new call and handoff call to occupy channel are in- creased. The strategy also takes into account the priority of different data types, and only when the data packet in high--priority data queue is empty, the data packets in general data queue can be transmitted. Expression for the dropping probability of handoff calls and the blocking probability of new calls and the dropping probability of data are derived. Through comparison with the channel reservation strategy and movable boundary strategy, it can be proved that the new handoff strategy provides much better performance improvement by reducing the dropping probability and the blocking probability.