WCDMA系统中正交可变扩频码的混合分配算法

针对WCDMA系统中各种正交可变扩频码（OVSF码）的单码分配方案，提出一种混合分配（HA）算法。HA算法分为初始码树划分和OVSF码分配2个阶段。仿真结果表明，HA算法很好地克服了crowded-first算法公平性差和RDA算法呼损率高的缺点，既降低了整个系统的平均呼损率，又对各种业务不失公平性。HA算法不需要码字重分配，极大地降低了算法的复杂度，适用于实时系统共享区域的设置，可以很好地解决不同业务的业务量变化问题。共享区域的容量为系统资源的30％～40％，此时能得到最佳的呼损率。

Hybrid Allocation Algorithm of Orthogonal Variable-Spreading-Factor Codes for WCDMA

A hybrid allocation (HA) algorithm, including two steps of initial partition of code tree and orthogonal variable-spreading-factor( OVSF) code allocation, is presented for wideband code division multiple access (WCDMA) system focusing on OVSF single-code allocation in this paper. Simulation results show that HA algorithm overcomes low fairness in crowded-first algorithm and high blocking probability in RDA algorithm. Computer simulations also show significant reduction in average blocking probability and excellent fairness for all kinds of services. Nonrearrangement decreases complexity and can be applied to real-time systems by using HA. Sharing area solves the problem of traffic load variation in different services and optimal blocking probability is achieved by setting best proportion of sharing area's capacity, i. e. , 30%-40% of the whole system.