Information Exchange Based Low-Complexity Slot Allocation in TDD-CDMA Cellular Systems

In this paper, we consider a predictive and distributed slot allocation scheme for transporting multi-class traffic over TDD-CDMA cellular networks with multiple cells, designed to maximize a general utility function that is concave increasing. We formulate the utility-maximizing slot allocation problem as a nonlinear integer programming problem, and provide a solution that can be realized efficiently in a distributed manner. Also, we derive sufficient conditions for a real-number solution to be optimal and develop an efficient algorithm to find a near-optimal integer solution. The effectiveness of the integer solution is demonstrated by showing that its gap with the optimal solution is small. We show by experiments that the proposed predictive method has a sufficient accuracy when there are many active users in cells. Extensive simulation results show that the proposed distributed slot allocation method performs very well in comparison to an existing method.