STS在多用户MC DS-CDMA系统中的研究

The Research of Space-Time Spreading in Multiuser MC DS-CDMA Systems

介绍了空时扩展(STS)发送分集的MC DS-CDMA(Mu lticarrierD irect Sequence-code D ivisionMu l-tip le Access)系统的整个发送接收过程,并建立了该过程的离散模型。同时将其与MC DS-CDMA系统的最大比合并(MRC)接收分集相比较。通过仿真比较了单发单收、MRC接收分集与STS发送分集的MC DS-CDMA系统的误码率(BER)性能。仿真结果表明,采用最大比合并接收分集的MC DS-CDMA系统的性能最好,采用STS发送分集的MC DS-CDMA系统性能次之,且随着多址干扰(MAI)的增加,两者的性能差距随之减小。发送分集的优势在于把接收端的复杂度移到发送端的同时提高了系统的性能。

This paper introduces the transmitting and receiving progress of MC DS-CDMA （multicarrier direct sequence-code division multiple access） systems with STS （space-time spreading） transmit diversity, and builds up the discrete system model. We also compare STS transmit diversity with MRC receive diversity in MC DS-CDMA systems. The BER （bit error ratio） performance of schemes of single transmit antenna and single receive antenna, MRC receive diversity and STS transmit diversity in MC DS-CDMA systems are simulated in the paper. The simulation results show that the performance of the MRC scheme is the best of the three schemes and that of the STS scheme is the second. The performance distance of the two schemes is shown to be smaller with increasing MAI （multiple access interference）. The advantage of STS transmit diversity lies in that it moves the complexity of the receiver to the transmitter and at the same time it improves the performance of systems.