TDD/CDMA系统交叉时隙干扰的解决方案

Research on Interference at Crossed Slot in TDD/CDMA Systems

针对时分双工/码分多址(TDD/CDMA)系统在动态调整上下行时隙的分配时会产生严重的交叉时隙干扰问题,提出了一种基于隔离区域的移动台间干扰的解决方案.隔离区域由移动台接收到的导频信号差值确定,该隔离区域范围较小,从而交叉时隙容量较大.同时分析了交叉时隙基站间干扰,结果表明,由于基站间传输条件较好,不能完全克服基站间干扰,因此TDD/CDMA系统(如时分同步CDMA(TD-SCDMA))的动态调整上下行切换点技术仍然很难应用于实际系统中.

Time division duplex-code division multiple access（TDD/CDMA）system can flexibly allocate uplink and downlink to be adapted to the asymmetrical service in theory. However, diversified swit- ching point will produce inter-cell interference at crossed slot. A new scheme is proposed to resolve the problem of inter-mobile station （MS） interference at crossed slot by setting the separate area. The separate area is determined by the difference of pilot signal received by the mobiles in the new scheme. Further more, the separate area is smaller than that in other schemes, so the coverage at crossed slot will be increased. The inter-base station （BS） interference at crossed slot is also analyzed as well. The numerical results illustrates that the inter-BS interference is much stronger due to the better transmission environment and the mobile system hardly resists the inter-BS interference. Therefore, it is difficult for the technology of diversified switching point to be applied in practical TDD/CDMA system, such as time division-synchronous code division multiple access （TD-SCDMA）.