Optimized Power Allocation for Pairwise Cooperative Multiple Access

• Published in: IEEE transactions on signal processing Vol. 56; no. 7; pp. 2994 - 3008
• Main Authors: Mesbah, W., Davidson, T.N.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-07-2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Achievable rate; Algorithms; Allocations; Applied sciences; Base stations; Boundaries; Channel state information; Channels; Closed-form solution; convex optimization; cooperative communications; decode-and-forward; Decoding; Detection, estimation, filtering, equalization, prediction; Exact sciences and technology; Formulations; Information, signal and communications theory; Interference; Mathematical analysis; Miscellaneous; Multiple access; Multiplexing; Partitioning algorithms; Quality of service; Resource allocation; Resource management; Signal and communications theory; Signal processing; Signal processing algorithms; Signal, noise; Studies; Telecommunications and information theory; Transmitters; Access control; Multiplexing; Multiple access; Parameter estimation; Resource allocation; Transmitter; Achievable rate; Algorithm; Power allocation; Convex programming; Algorithm performance; Optimal allocation; decode-and-forward; Channel estimation; Signal processing; convex optimization; Resource management; cooperative communications; Service quality
• ISSN: 1053-587X; 1941-0476
• DOI: 10.1109/TSP.2008.917390

Multiple access schemes in which the transmitting nodes are allowed to cooperate have the potential to provide higher quality of service than conventional schemes. In the class of pair-wise cooperative multiple access schemes in which channel state information is available at the transmitters, the allocation of transmission power plays a key role in the realization of these quality of service gains. Unfortunately, the natural formulation of the power allocation problem for full-duplex cooperative schemes is not convex. It is shown herein that this non-convex formulation can be simplified and recast in a convex form. In fact, closed-form expressions for the optimal power allocation for each point on the boundary of an achievable rate region are obtained. In practice, a half-duplex cooperative scheme, in which the channel resource is partitioned in such a way that interference is avoided, may be preferred over a full-duplex scheme. The channel resource is often partitioned equally, but we develop an efficient algorithm for the joint allocation of power and the channel resource for a modified version of an existing half-duplex cooperative scheme. We demonstrate that this algorithm enables the resulting scheme to attain a significantly larger fraction of the achievable rate region for the full duplex case than the underlying scheme that employs a fixed resource allocation.