Energy-Efficient Power Control in Multipath CDMA Channels via Large System Analysis

TL;DR

This paper develops a large system analysis approach for energy-efficient power control in multipath CDMA uplinks, proposing a decentralized algorithm and predicting network performance with high accuracy.

Contribution

It introduces a new decentralized power control algorithm based on large system analysis for energy efficiency maximization in multipath CDMA channels.

Findings

The LSA-based algorithm achieves energy efficiency close to optimal in simulations.

LSA accurately predicts network performance metrics like SINR and utility.

Comparison of linear receivers shows differences in energy efficiency at equilibrium.

Abstract

This paper is focused on the design and analysis of power control procedures for the uplink of multipath code-division-multiple-access (CDMA) channels based on the large system analysis (LSA). Using the tools of LSA, a new decentralized power control algorithm aimed at energy efficiency maximization and requiring very little prior information on the interference background is proposed; moreover, it is also shown that LSA can be used to predict with good accuracy the performance and operational conditions of a large network operating at the equilibrium over a multipath channel, i.e. the power, signal-to-interference-plus-noise ratio (SINR) and utility profiles across users, wherein the utility is defined as the number of bits reliably delivered to the receiver for each energy-unit used for transmission. Additionally, an LSA-based performance comparison among linear receivers is carried out in terms of achieved energy efficiency at the equilibrium. Finally, the problem of the choice of the utility-maximizing training length is also considered. Numerical results show a very satisfactory agreement of the theoretical analysis with simulation results obtained with reference to systems with finite (and not so large) numbers of users.