Energy Efficiency Optimization of FBMC/OQAM-Based Massive MIMO Systems Subject to Electromagnetic Exposure Constraints

• Published in: IEEE transactions on vehicular technology Vol. 73; no. 11; pp. 17247 - 17264
• Main Authors: Rai, Sudhakar, Singh, Prem, Sharma, Ekant, Jagannatham, Aditya K., Hanzo, Lajos
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Closed form solutions; Constraints; Electromagnetic fields; Electromagnetic fields (EMF) exposure; Energy efficiency; Exact solutions; Exposure limits; FBMC/OQAM; Filter banks; Interference; intrinsic interference; Iterative algorithms; Lagrangian dual transform; Lower bounds; Massive MIMO; massive multiple-input multiple-output (MIMO); Maximization; MIMO communication; multi-carrier modulation; nested quadratic-transform (NQT); OFDM; Optimization; Quadratures; Specific absorption rate; Symbols; Transforms; Uplink; Waveforms
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2024.3428974

The performance of offset-quadrature-amplitude-modulated filter bank multi-carrier (FBMC/OQAM) waveform based on massive multiple-input multiple-output (MIMO) systems is investigated considering not only the transceiver's classic metrics, but also the health concerns associated with exposure to electromagnetic fields (EMF). Closed-form expressions are obtained for the lower-bounds on the uplink spectral efficiency (SE) for FBMC/OQAM-based Massive MIMO systems with both the maximum ratio combiner (MRC) and zero-forcing (ZF) receivers, in the face of realistic imperfect channel state information (CSI). Subsequently, by employing our closed-form SE expressions, a framework is developed for maximizing the global energy efficiency (GEE) of the proposed FBMC/OQAM-based system subject to both power and EMF exposure constraints. A nested quadratic-transform (NQT)-based approach is proposed next for maximizing the non-convex GEE objective by first approximating it as a concave-convex function and then by applying the quadratic transform. Subsequently, a low-complexity iterative algorithm is developed that sequentially applies the Lagrangian dual transform, quadratic transform and Dinkelbach's transform to obtain a closed-form solution of the GEE optimization problem formulated. Our simulation results verify the analytical SE expressions and also demonstrate the improved GEE of the proposed FBMC-based massive MIMO systems subject to the EMF exposure limits.