Optimum Power and Rate Allocation for Coded V-BLAST: Average Optimization

TL;DR

This paper develops an analytical framework for optimizing power and rate allocations in coded V-BLAST systems to minimize outage probability, providing closed-form solutions and insights into their performance and robustness.

Contribution

It introduces a comprehensive analytical approach with closed-form expressions for optimal allocations, revealing their effects on outage probability and diversity gain in coded V-BLAST systems.

Findings

Uniform power allocation is nearly optimal at low outage levels.

Average rate allocation yields significant performance improvements.

Power allocation offers modest SNR gains limited by antenna count.

Abstract

An analytical framework for performance analysis and optimization of coded V-BLAST is developed. Average power and/or rate allocations to minimize the outage probability as well as their robustness and dual problems are investigated. Compact, closed-form expressions for the optimum allocations and corresponding system performance are given. The uniform power allocation is shown to be near optimum in the low outage regime in combination with the optimum rate allocation. The average rate allocation provides the largest performance improvement (extra diversity gain), and the average power allocation offers a modest SNR gain limited by the number of transmit antennas but does not increase the diversity gain. The dual problems are shown to have the same solutions as the primal ones. All these allocation strategies are shown to be robust. The reported results also apply to coded multiuser detection and channel equalization systems relying on successive interference cancelation.