Power Efficiency, Overhead, and Complexity Tradeoff of IRS Codebook Design – Quadratic Phase-Shift Profile
Jamali V, Najafi M, Schober R, Vincent Poor H (2021)
Publication Type: Journal article
Publication year: 2021
Journal
DOI: 10.1109/LCOMM.2021.3058063
Abstract
In this paper, we focus on large intelligent reflecting surfaces (IRSs) and propose a new codebook construction method to obtain a set of predesigned phase-shift configurations for the IRS unit cells. Since the overhead for channel estimation and the complexity of online optimization for IRS-assisted communications scale with the size of the phase-shift codebook, the design of small codebooks is of high importance. We show that there exists a fundamental tradeoff between power efficiency and the size of the codebook. We first analyze this tradeoff for baseline designs that employ a linear phase-shift across the IRS. Subsequently, we show that an efficient design for small codebooks mandates higher-order phase-shift variations across the IRS. Consequently, we propose a quadratic phase-shift design, derive its coefficients as a function of the codebook size, and analyze its performance. Our simulation results show that the proposed design yields a higher power efficiency for small codebooks than the linear baseline designs.
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APA:
Jamali, V., Najafi, M., Schober, R., & Vincent Poor, H. (2021). Power Efficiency, Overhead, and Complexity Tradeoff of IRS Codebook Design – Quadratic Phase-Shift Profile. IEEE Communications Letters. https://dx.doi.org/10.1109/LCOMM.2021.3058063
MLA:
Jamali, Vahid, et al. "Power Efficiency, Overhead, and Complexity Tradeoff of IRS Codebook Design – Quadratic Phase-Shift Profile." IEEE Communications Letters (2021).
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