Spectral Efficiency of OFDMA Cognitive Radios under Imperfect Cross-Link Knowledge

TL;DR

This paper investigates the spectral efficiency of OFDMA cognitive radios with imperfect cross-link knowledge, proposing a stochastic approach and resource allocation algorithms to optimize performance under interference constraints.

Contribution

It introduces a stochastic method for managing interference in OFDMA CRs with imperfect channel knowledge and derives a CDF expression for SINR to evaluate spectral efficiency.

Findings

Stochastic approach effectively mitigates interference on primary users.

Derived CDF of SINR for performance evaluation.

Simulation results confirm analytical predictions.

Abstract

We analyze the spectral efficiency performance and limits of orthogonal frequency-division multiple access (OFDMA) cognitive radios (CRs) with an imperfect availability of cross-link knowledge. In particular, in contrast to the conventional `average' and `worst' cases of channel estimation error in the literature, we propose a stochastic approach to mitigate the total imposed interference on primary users. Channel-adaptive resource allocation algorithms are incorporated to optimize the cognitive system functionality under transmit and interference power constraints. An expression for the cumulative density function (cdf) of the received signal-to-interference-plus-noise ratio (SINR) is developed to evaluate the average spectral efficiency. Analytical derivations and results are confirmed through computer simulations.