Feedback Bits Allocation for Interference Minimization in Cognitive Radio Communications

TL;DR

This paper proposes feedback bits allocation strategies in cognitive radio systems to minimize interference to primary users, optimizing feedback distribution based on channel gains and interference constraints.

Contribution

It introduces low-complexity solutions for feedback bits allocation to minimize interference and feedback bits in limited feedback cognitive radio systems.

Findings

Proposed feedback allocation reduces maximum interference effectively.

Optimized feedback bits minimize total feedback under interference constraints.

Simulation confirms the effectiveness of the proposed methods.

Abstract

This letter studies the limited feedback cognitive radio system, where the primary users (PU) are interfered by the secondary transmitter (ST) due to the imperfect beamforming. We propose to allocate the feedback bits among multiple PUs to minimize the maximum interference caused by the ST, by exploiting the heterogeneous average channel gains. In addition, we study the problem of minimizing the total feedback bits under a predefined interference threshold at the PUs. The solutions with low complexity are proposed for the studied problems, and the performances of bit allocations are analyzed. Simulation results validate our analysis and demonstrate that the proposed solutions work very well in terms of minimizing the maximum interference caused by the ST and minimizing the total feedback bits under predefined interference threshold at the PUs for limited feedback CR system.