直扩超宽带系统中基于线性约束恒模算法的多用户检测

Linearly Constrained Constant Modulus Algorithm Based Multiuser Detection for DS-UWB Systems

针对超宽带室内传输环境的慢时变特性以及超宽带信号的恒模调制方式,提出了一种基于线性约束恒模算法的盲自适应多用户检测方案。该方案首次将恒模算法引入直扩超宽带系统中的多用户检测,应用盲信号处理方法推导了恒模算法在线性约束条件下的全局最优性。理论分析及仿真结果表明,与基于训练序列的自适应多用户检测相比,该方案提高了有效的信息传输容量,同时在输出信干比及误码性能方面的损失不超过3 dB,有效地做到了传输容量与误码性能之间的折衷,适用于室内超宽带的多用户高速接入场合。

By exploiting the quasi-static or slowly time varying character for indoor ultra-wideband transmission environment and the constant-modulus modulation of ultra-wideband signals, a linearly constrained constant-modulus algorithm （LCCMA） based blind adaptive multiuser detection （MUD） scheme is presented for direct sequence ultra-wideband （DS-UWB） systems. In the proposed approach, the constant-modulus algorithm （CMA） is first introduced into the MUD for DS-UWB systems. Moreover, the global optimum property of the LCCMA is derived via blind signal processing method. Theoretical analysis and simulation results show that, compared with the training sequence based adaptive MUD, the proposed scheme can increase the transmission ca- pacity of effective information with a loss of no higher than 3 dB in terms of both output signal-in- terference ratio （SIR） and bit error ratio （BER）. Therefore, it reaches a preferable tradeoff be- tween transmission capacity and BER performance, and then can be considered as a compromising candidate for indoor high-speed, UWB multiuser access scenarios.