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arXiv · 2611.00801

Joint Transmit Power and Reflection Coefficient Optimization for Underlay Cognitive Radio Ambient Backscatter Communication

Chabalala S. Chabalala·Peter Odero Akuon·Zhen Gao
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Abstract

The integration of cognitive radio (CR) technology with backscatter communication offers a promising solution for developing spectrum-efficient and low-power wireless networks. In this paper, we investigate the performance of an underlay cognitive radio ambient backscatter communication (CR-AmBC) system operating under primary network (PN) interference constraints. The objective is to maximize the performance of the CR-AmBC system while protecting the PN from interference. Differing from prior work, our formulation jointly accounts for: (i) interference from the PN on the CR receivers, (ii) interference from the backscatter device (BD) on the PN receiver, and (iii) imperfect successive interference cancellation (i-SIC) at the secondary destination. We propose a joint transmit power and reflection coefficient optimization framework that incorporates the minimum data rate requirements, the PN interference constraint, and i-SIC for decoding the BD signal. The nonconvex problem is decomposed into two subproblems solved via alternating optimization: (a) a closed-form expression for the feasible transmit power given a fixed reflection coefficient, and (b) an efficient one-dimensional search for the reflection coefficient. We prove that the power update is optimal, reducing the joint problem to a one-dimensional search, with monotone convergence and $\mathcal{O}(KN_β)$ complexity for $K$ iterations and $N_β$ search points. We present a comprehensive simulation-based performance evaluation and the results demonstrate that the proposed joint transmission power and reflection coefficient optimization provides an effective strategy to maximize the performance of the CR-AmBC system without violating the PN protection constraints.

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Chabalala S. Chabalala, Peter Odero Akuon, Zhen Gao. 2026-10-31. Joint Transmit Power and Reflection Coefficient Optimization for Underlay Cognitive Radio Ambient Backscatter Communication. https://arxiv.org/abs/2611.00801

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