Abstract:

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 switching point will produce the inter-cell interference at crossed slot. In this paper, a new scheme is proposed which can be used 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 increases. The inter-base station (BS) interference at crossed slot is also analyzed in this paper. The numerical results illustrate 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).

Key words: time division duplex - code division multiple access, diversified switching point, interference at crossed slot, separate area