Comparison of time slot allocation strategies for CDMA/TDD systems

Abstract

The CDMA/TDD system with unbalanced slot allocation between the uplink and downlink is a good solution for the traffic (load) asymmetry between two links in cellular mobile multimedia communications. However, the level of traffic asymmetry may be significantly different from cell to cell. We investigate a slot allocation strategy (DA strategy), by which each cell has its own slot allocation (differentiated from other cells) according to the level of traffic asymmetry. We compute the system capacity with DA strategy and find out the optimal slot allocation for the system. We also compare the maximum capacity to that with another strategy (SA strategy), by which all cells have the same slot allocation. As a result, this paper shows that the system with DA strategy outperforms that with SA strategy in the aspect of capacity.