一种基于切换迟滞的LTE自适应计时水平切换算法

An Adaptive Timer Handoff Algorithm Based on Handoff Hysteresis in LTE

针对LTE固定计时切换算法存在的缺点,提出了一种自适应计时切换算法.该算法依据当前移动台与原服务小区的距离di及rank,ram和p这3个可变常数,计算其实时的切换计时值T,从而实时改变切换等待时间.仿真结果表明:采用固定计时切换算法,且计时值T设置偏大时,移动台需移动到离原服务小区较远的地方才能发生切换,此时移动台接收原服务小区的信号强度很差;而自适应计时切换算法不仅能消除乒乓效应,减少平均切换次数,且切换时拥有较好平均信号强度,切换位置更集中合理,总体性能达到最佳效果.

An adaptive timer handoff algorithm with respect to the shortcoming of fixed timer handoff algorithm in LTE was proposed.In the algorithm, the real-time handoff timer value T was calculated based on the distance di between current mobile station and original serving cell as well as three constant variables： rank, ram and p, thus changing the handoff waiting time in real time.The simulation results showed that the handoff occurs only when the mobile station needs to move to a far position from the original serving cell in the fixed timer handoff algorithm and larger set timer value T, and the strength of signals received by the mobile station in the original serving cell is poor;however, in the adaptive timer handoff algorithm, the ping-pong effect can be eliminated, the average handoff times are reduced, the mean strength of signals at handoff is better, the handoff position concentrates rationally and the overall performance reaches to the optimal effect.