An Efficient Dynamic Channel Assignment with Channel Locked for TDD-CDMA Systems

Time division duplex (TDD) is an efficient approach to combat the traffic asymmetry issues via adapting the resource (time slots) for uplink and downlink in TDD-CDMA systems. However, the cross-slot interference is caused by the asymmetry traffic between mobile subscribers and base stations, which can seriously degrade the system performance. In this paper, an efficient dynamic channel assignment with channel locked (DCA/CL) is investigated for TDD-CDMA communication systems. The cell is divided into three sections by directional antennas. The above tri-sector cell architecture possesses additional orthogonality inherently due to the directivity of directional antenna, which can provide an additional degree of freedom in allocating radio resource with the channel locked directly in the section of the neighbor cell. Further, the proposed scheme is combined with transmission power control to decrease the interference, and is also evaluated by computer simulation. The results show it efficiently reduces the failure probability and achieves better system performance.