Spreading Code and Widely-Linear Receiver Design: Non-Cooperative Games for Wireless CDMA Networks

The issue of non-cooperative transceiver optimization in the uplink of a multiuser wireless code division multiple access data network with widely-linear detection at the receiver is considered. While previous work in this area has focused on a simple real signal model, in this paper a baseband complex representation of the data is used, so as to properly take into account the I and Q components of the received signal. For the case in which the received signal is improper, a widely-linear reception structure, processing separately the data and their complex conjugates, is considered. Several non-cooperative resource allocation games are considered for this new scenario, and the performance gains granted by the use of widely-linear detection are assessed through theoretical analysis. Numerical results confirm the validity of the theoretical findings, and show that exploiting the improper nature of the data in non-cooperative resource allocation brings remarkable performance improvements in multiuser wireless systems. Index Terms Widely-linear filtering, improper noise, multiuser detection, MMSE receiver, CDMA, power control, spreading code optimization, game theory, SINR maximization, MSE minimization, sum capacity, energy efficiency. The research was supported in part by the U. S. National Science Foundation under Grant CNS-06-25637. This paper was partly presented at the 2009 IEEE Sarnoff Symposium, Princeton, NJ, March 2009, and at the Int. Conference on Game Theory for Networks, Istanbul (Turkey), May 2009. Stefano Buzzi and Alessio Zappone are with DAEIMI, University of Cassino, Via G. Di Biasio, 43, I-03043 Cassino (FR), Italy (e-mail: [email protected], [email protected]); H. Vincent Poor is with the School of Engineering and Applied Science, Princeton University, Princeton, NJ, 08544, USA (e-mail: [email protected]).