Abstract:

Dynamic metasurface antenna (DMA) array is a novel structure to implement the analog-digital hybrid beamforming, in which the analog beamforming part is realized by the DMA and thus the system complexity is low. The DMA array-based hybrid transmit beamforming is studied, and the core problem is the joint optimization of analog and digital transmit weights. In virtue of alternating optimization, this paper decomposes the joint optimization problem into several sub-problems and then proposes a solving method by using alternating direction multiplier method (ADMM). The proposed method simplifies the problem model by introducing auxiliary variables firstly, and then resolves the auxiliary variables, digital weights and analog weights by alternating optimization. Among them, the solution of auxiliary variables has a closed-form expression, after decoupling, the digital weights and analog weights are solved separately by ADMM, respectively. Simulation results show that the proposed DMA array has better performance of hybrid transmit beamforming than the typical phase-only hybrid array and phase-only array under constant modulus constraints.

Key words: dynamic metasurface antenna (DMA), transmit beamforming, hybrid beamforming, alternating direction multiplier method (ADMM)