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.Comment: submitted to IEEE Transactions on Information Theory, June 200

A Blind Widely Linear Minimum-Output Energy Algorithm

In this paper, a novel blind minimum-output-energy (MOE) algorithm for adjustment of the unbiased widely linear (WL) minimum mean-squared error (MMSE) filter for multiple access interference (MAI) suppression for direct-sequence code-division multiple access (DS-CDMA) is introduced and analyzed. We analyze the steady-state signal-to-interference-plus-noise ratio (SINR) and the convergence of the proposed blind WL stochastic gradient algorithm. Wherever possible comparisons with the linear blind MOE algorithm are made. Both analytical considerations and simulations show in good agreement the superiority of the novel WL adaptive algorithm. Nevertheless, it requires a lower computational complexity than its linear counterpart