改进型OVSF码随机动态分配算法

Improved Random Dynamic Allocation Algorithm of OVSF Code

针对WCDMA(Wideband Code-Division Multiple Access)系统下行链路随机动态码分配算法存在码阻塞概率大、进行最小代价分支搜索信令开销大的问题,提出了一种改进型动态码分配算法。该算法采用搜索最小代价函数值、以邻近原则进行码树重排、释放同级码字中具有最大代价函数值的码字策略。仿真结果表明,改进型动态码分配算法码阻塞概率低于随机动态码分配算法的码阻塞概率。在业务量为16 Erl时,改进型动态码分配算法使系统码阻塞概率降低18.37%,同时该算法能有效降低系统的复杂度。

Random dynamic code allocation algorithm has a high blocking probability and too much overhead cost in searching for the minimum-cost branche in downlink of WCDMA （ Wideband Code-Division Multiple Access） systems, so we proposed an improved version of a dynamic code allocation algorithm. The algorithm uses the minimum-cost searching function to the code tree rearrangement based on the principles of neighbouring, and releases of a code at the same level with the greatest cost function in the value of the code strategy. The simula- tion results show that the probability of improved algorithm is less than the algorithm of random dynamic code allocationt algorithm. When the traffic load is 16 Erl, the improved version of a dynamic code allocationt algorithm can reduce the probability by 18.37%. And the same time the improved algorithm can effectively reduce the complexity of the system.