多网络共存下基于贝叶斯的垂直切换算法

摘要

To solve the problem that current vertical switching technologies generally cannot support vertical handover in multi-network handover,this paper proposes an improved vertical handover algorithm based on Bayesian Decision Theory. First, the handover probability distribution associated with multi-condition is established according to the signal strength of access network,bit error rate( BER) ,blocking rate and actual demand on network from different customer service to calculate a priori handover probability. Then, the posterior probability is calculated on account of the Bayesian Decision Algorithm to perform a dicision com-parison,thereby selecting an optimal access network. Simulation results indicate that the algorithm can not only effectively achieve vertical handover among the different wireless access technologies,avoid needless handover,improve the successful probability of handover, but also reduce the blocking of communication hotspots so as to provide users with better quality services when an average load of each network reaches 30% ~40%.%针对目前的垂直切换技术普遍不能满足多网络下的切换问题，提出了一种改进的基于贝叶斯决策的垂直切换算法。首先根据接入终端网络的信号强度、网络负载、误码率和网络阻塞率以及用户业务对网络的实际需求偏好建立多条件相关的切换概率分布，计算出先验切换概率；然后通过贝叶斯决策算法计算出后验概率来进行判决比较，从而选取最优的接入网络。仿真结果表明，该算法不仅能有效地实现不同接入技术之间的垂直切换，从而减少不必要的切换，提高了切换成功的概率，而且还能在维持各网络平均负载达到30%~40%时减轻通信热点的阻塞情况，为用户提供更优的服务质量。