Joint Beamforming Optimization for Reconfigurable Intelligent Surface-Enabled MISO-OFDM Systems |
| |
作者姓名: | Keming Feng Xiao Li Yu Han Yijian Chen |
| |
作者单位: | National Mobile Communications Research Laboratory;ZTE Corporation;State Key Laboratory of Mobile Network and Mobile Multimedia Technology |
| |
基金项目: | supported in part by the National Natural Science Foundation of China under Grants 61971126 and 61921004;ZTE Corporation;State Key Laboratory of Mobile Network and Mobile Multimedia Technology. |
| |
摘 要: | In this paper,we investigate the reconfigurable intelligent surface(RIS)-enabled multiple-input-single-output orthogonal frequency division multiplexing(MISO-OFDM)system under frequency-selective channels,and propose a low-complexity alternating optimization(AO)based joint beamforming and RIS phase shifts optimization algorithm to maximize the achievable rate.First,with fixed RIS phase shifts,we devise the optimal closedform transmit beamforming vectors corresponding to different subcarriers.Then,with given active beamforming vectors,near-optimal RIS reflection coefficients can be determined efficiently leveraging fractional programming(FP)combined with manifold optimization(MO)or majorization-minimization(MM)framework.Additionally,we also propose a heuristic RIS phase shifts design approach based on the sum of subcarrier gain maximization(SSGM)criterion requiring lower complexity.Numerical results indicate that the proposed MO/MM algorithm can achieve almost the same rate as the upper bound achieved by the semidefinite relaxation(SDR)algorithm,and the proposed SSGM based scheme is only slightly inferior to the upper bound while has much lower complexity.These results demonstrate the effectiveness of the proposed algorithms.
|
关 键 词: | reconfigurable intelligent surface(RIS) OFDM joint beamforming optimization fractional programming majorization-minimization manifold optimization |
本文献已被 维普 等数据库收录! |