采用空时扩谱技术的CDMA系统在多用户多径条件下的性能
The Performance of CDMA Systems withSpace-Time Spreading Approach underthe Conditions of Multi-users and Multipaths
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摘要: 该文研究了多用户多径条件下采用空时扩谱(STS)技术的CDMA系统的性能。该STS设计方案在基站使用两天线阵元,在移动终端使用一全向天线，与一新型扩谱算法联合使用，可提高下行链路的性能。与现有的研究不同的是，该文在单用户STS设计方案的基础上，进一步研究了多用户的情况，给出了理论分析和误码率的表达式。通过仿真结果表明，这种方案相对于传统方案，性能有一定提高，可有效降低误码率，改善下行链路的接收质量，但系统实现的复杂性增加，对移动台有较多的技术要求，STS技术有待进一步完善。
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关键词:
- 空时扩谱; 发射分集; 多径接收
Abstract: The paper studies the performance of CDMA systems with the space-fcime ap-proach under the conditions of multi-users and multipaths. The space-time spreading scheme with a novel algorithm can improve the downlink performance by using two antenna elements at the base station and one antenna at the mobile terminal. Different from the present other results, the multi-user systems have been analyzed, the detailed theory analysis and expression of bit-error-probability have been provided, based on the scheme of single-user systems. Moreover, the simulation results show that this scheme obtains an improvement of the CDMA system performance comparing to the conventional approaches, demonstrat-ing that it is a practical way to decrease the bit error rate and improve the qiiality of the downlink of CDMA systems. Meantime, the implementation complexity of the systems has increased, there are many new technical requirements for mobiles to be satisfied, and the STS technique needs to be improved. -
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