【摘 要】
：
Effectively supporting millimeter-wave (mmWave) beamforming is still a major challenge in 5G cloud radio access network (5G C-RAN) systems with evolved common public radio interface-based (eCPRI-based) fronthaul.Herein,an optical true time delay pool base
【机 构】
：
School of Information and Communication Engineering,Zhongshan Institute,University of Electronic Sci
论文部分内容阅读
Effectively supporting millimeter-wave (mmWave) beamforming is still a major challenge in 5G cloud radio access network (5G C-RAN) systems with evolved common public radio interface-based (eCPRI-based) fronthaul.Herein,an optical true time delay pool based hybrid beamforming (OTTDP-HBF) scheme,enabling centralized beamforming control,is proposed for mmWave 5G C-RAN systems.The weight control of the OTTDP-HBF is physically implemented by a pre-designed optical wavelength matrix which is mapped from a series of optical carriers.After introducing optical true time delay,this optical wavelength matrix then maps to the defined OTTDP.In this scheme,all physical implementation and the computational processing of analog beamforming can be centrally deployed into a centralized unit or distributed unit (CU/DU).Each active antenna unit (AAU) therefore becomes very simple.For single-user and multi-user scenarios,the OTTDP-based hybrid precoders are formulated respectively.In the developed OTTDP-based multi-user hybrid precoder,the spectral efficiency is improved by making use of all RF chains.For a 9-element uniform planar array deployed at an AAU,a designed example of the OTTDP-HBF is presented,where spectral efficiency curves obtained via different precoding schemes for single-user and multi-user scenarios are compared and discussed respectively.
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