An efficient dynamic channel allocation for asymmetrical traffic in TDD-CDMA systems

The increasing demand of higher data rates, the variation of the radio channel, and the inherent traffic asymmetry between the uplink and downlink impose many challenges on spectrum and radio resource management in wireless communication system. Time division duplex (TDD) is an efficient approach to combat the traffic asymmetry issues via adapting the resource (Time slots) for uplink and downlink. However, the asymmetry traffic will cause cross-slot interference between mobile subscribers and base stations, which can seriously degrade the system performance. An efficient dynamic channel assignment with channel locked (DCA/CL) is investigated for TDD-CDMA communication systems in this paper. The channel allocation schemes for uplink and downlink are addressed. The cell is divided into three sections by directional antennas, the locked channel is directly only in the section of the neighbor cell. The proposed scheme is evaluated by computer simulation and the results show that the proposed scheme efficiently reduces the failure probability and achieve better system performance.