用于WCDMA系统中的改进型恒模多用户检测算法

Improved Constant Modulus Algorithm of Multiuser Detection in WCDMA Systems

提出一种适应WCDMA(Wide code division multiple access)系统的改进型恒模多用户检测算法,根据二级扩频调制结构,多址干扰的循环平稳周期等于扰码周期和扩频因子的最小公倍数,为使恒模算法适应这种扩频调制结构,改进型恒模算法中权系数的更新迭代公式随循环平稳周期变化。实验表明:在目标误码率为10-3的4用户WCDMA系统中,改进型恒模多用户检测算法能获得1 dB的增益。

An improved constant modulus algorithm（CMA） for adaptive multiuser detection is proposed. According to the two-layered spreading modulation in the wide code division multiple access（WCDMA） systems, the cyclo-stationary period of multiple access interference is equal to the least common multiple between the lengths of the spreading code and the scrambling code. The coefficient update equation depends on the cyclo-stationary period in the improved algorithm, instead of the spreading factor in the conventional one. These appropriate modifications make the CMA more suitable to the WCDMA systems. Simulation results illustrate that the improved CMA can achieve 1 dB of the gain on signal-to-noise ratio in a 4-user system on the target BER of 10^-3.