Asymptotic spectral efficiency of LMMSE multi-user multi-signature MC-CDMA in frequency-selective Rayleigh fading

Abstract

In this paper we present an asymptotic analysis of a multi-signature Multi-Carrier CDMA communications system. Such a system is suited to scalable data rate services with decentralized control. Specifically, we derive the asymptotic SINR at the output of a multiuser Linear Minimum Mean Squared Error (LMMSE) receiver and the asymptotic sum spectral efficiency of both the LMMSE and optimal receivers. Simulation studies demonstrate that the asymptotic results closely predict the performance of practical finite systems.

Eigenvalue Distributions of Sums and Products of Large Random Matrices Via Incremental Matrix Expansions

“…Also shown are the values obtained using the 7 The authors thank P. Loubaton for pointing this out. approximate asymptotic results of [18]. As expected, the exact solution matches the empirical values, and moreover, the approximate solution of [18] is seen to be very accurate.…”

“…approximate asymptotic results of [18]. As expected, the exact solution matches the empirical values, and moreover, the approximate solution of [18] is seen to be very accurate. As mentioned previously, the computational complexity of the exact solution in Theorem 1 is significantly less than that of the approximate solution.…”

“…In this paper, we extend the approach in order to consider certain multi-user CDMA systems in frequency-selective channels, which includes the single-cell multiple-signature-per-user uplink and the multiple-cell downlink. Specifically, we consider direct-sequence (DS) and multi-carrier (MC) CDMA systems, which are well known to be equivalent in the large system limit (see e.g., [18]), and as such we refer to the common model as DS/MC-CDMA. We previously presented an approximate solution to a special case of this problem in [18,19], where a sum of nonfree matrices is approximated by a sum of equivalent unitarily invariant matrices, which are asymptotically free.…”

“…Specifically, we consider direct-sequence (DS) and multi-carrier (MC) CDMA systems, which are well known to be equivalent in the large system limit (see e.g., [18]), and as such we refer to the common model as DS/MC-CDMA. We previously presented an approximate solution to a special case of this problem in [18,19], where a sum of nonfree matrices is approximated by a sum of equivalent unitarily invariant matrices, which are asymptotically free. In this paper, we determine an exact solution to the problem, which is also significantly easier to compute than the approximate result in [18].…”

Adaptive Signal Processing Techniques for Robust, High Capacity Spread- Spectrum Multiple Access

“…We have analyzed the performance of MC-CDMA in the presence of frequency-selective Rayleigh fading with multiple users, and multiple signatures per user in [11,26,28,32]. Our results apply in the large system limit as signatures and processing tend to infinity with fixed ratio, and enable the computation of performance measures as a function of system parameters such as data rates per user, noise level, and number of users.…”