Power control and scheduling with minimum rate constraints in clustered multihop TD/CDMA wireless ad hoc networks

In order to achieve high end-to-end throughput in a multihop wireless ad hoc network, TD/CDMA has been chosen as the Medium Access Control (MAC) scheme due to its support for high network throughput in a multihop environment. The associated power control and scheduling problem needs to be addressed to optimize the operations of TD/CDMA. In this paper, cluster-based architecture is introduced to provide centralized control within clusters, and the corresponding power control and scheduling schemes are derived to maximize a network utility function and guarantee the minimum rate required by each traffic session, given routes for multiple end-to-end multihop traffic sessions. Because the resulted optimal power control reveals bang-bang characteristics, that is, scheduled nodes transmit with full power while other nodes remain silent, the joint power control and scheduling problem is reduced to a scheduling problem. The multi-link version of the throughput-optimal and the proportional fair scheduling algorithms for multihop wireless ad hoc networks are proposed. In addition, a generic token counter mechanism is employed to satisfy the minimum rate requirements. By ensuring different minimum rate for different traffic sessions, service differentiation is also achieved. Approximation algorithms are suggested to reduce the computational complexity. In networks that are lack of centralized control, distributed scheduling algorithms are also derived and fully distributed implementation is provided. Simulation results demonstrate the effectiveness of the proposed schemes. Copyright © 2006 John Wiley & Sons, Ltd.