蜂窝网中基于分布式约束满足算法的改进信道分配

摘要

随着蜂窝网业务需求的不断增长,如何利用有限的信道资源在各小区间进行复用,以便既能避免移动用户之间的干扰,又能满足所有移动用户的话务请求,使蜂窝系统容量大大增加,已成为一项重要研究课题.此类问题属于NP-hard的信道分配问题(Channel Assignment Problem,CAP),将CAP问题形式化为分布式约束满足问题(DCSP),然后提出基于改进现有的信道分配策略,以获得更高的信道利用率、较令人满意的系统服务质量,尽可能满足所有用户的话务请求.将利用尽可能简单、搜寻时间短的算法,并将现有的benchmark问题进行仿真.实验表明,该方案对有效改进信道分配问题,充分利用有限的信道资源,降低系统的阻塞率,有着较好的应用前景.%As demands grow for wireless communication systems and the limited number of channel resources, the channel assignment problem(CAP) becomes increasingly important The goal of channel assignment is to reduce the interferences, and enhance the capacity. CAP is a well-known NP-hard problem. In this paper, we modeled CAP as a Distributed Constraint Satisfaction Problem(DSCP) with fully considerations on all constraints of interferences, then proposed an improve channel assignment approach to minimized more required number of channels in cellular mobile system and minimize the number of blocked hosts. We also provided one kind of complete search algorithms, which outperforms others by providing quasi-optimal solutions at a related lower cost and time. We evaluated the performance of our approach in solving CAP, which is based on the existing benchmark. The simulation result shows that our approach provides optimal solutions and minimizes call failures, which is more feasible and easy to be applied in practical engineering.