DocumentCode :
163394
Title :
Investigation on Beamforming Control Methods in Base Station Cooperative Multiuser MIMO Using Block-Diagonalized Beamforming Matrix
Author :
Nonaka, Nobuhide ; Kakishima, Yuichi ; Higuchi, Kenichi
Author_Institution :
Grad. Sch. of Sci. & Technol., Tokyo Univ. of Sci., Tokyo, Japan
fYear :
2014
fDate :
14-17 Sept. 2014
Firstpage :
1
Lastpage :
5
Abstract :
This paper investigates a beamforming control method in base station (BS) cooperative multiuser multiple-input multiple-output (MIMO) transmission assuming a block-diagonalized unitary beamforming matrix. More specifically, we comprehensively compare open-loop type random (opportunistic) beamforming control to codebook-based closed-loop type beamforming control. The proportional fair (PF)-based scheduling is assumed, and the number of users, codebook size, and delay time of the feedback signal from the user terminals are taken into account in the comparison. Based on numerical results, codebook-based beamforming control with a large codebook size achieves higher system throughput than random beamforming when the number of users is small and the feedback delay time is short. However, we show that when the number of users is large and the feedback delay time is long, random beamforming achieves higher system-level throughput than codebook-based beamforming. This implies that the transmission-rate control with random beamforming is more robust against channel variation than that with codebook-based beamforming. These results suggest that random beamforming, which requires a lower feedback overhead than the codebook-based beamforming, is a promising beamforming strategy in future radio access.
Keywords :
MIMO communication; array signal processing; closed loop systems; cooperative communication; feedback; matrix algebra; multi-access systems; open loop systems; scheduling; synchronisation; telecommunication control; BS; PF-based scheduling; base station; beamforming control methods; beamforming strategy; block-diagonalized unitary beamforming matrix; channel variation; closed-loop type beamforming control; codebook size; codebook-based beamforming; cooperative multiuser MIMO transmission; feedback delay time; feedback overhead; feedback signal; multiple-input multiple-output transmission; open-loop type random beamforming control; opportunistic beamforming control; proportional fair-based scheduling; radio access; transmission-rate control; user terminals; Array signal processing; Delays; Interference; MIMO; Signal to noise ratio; Throughput; Vectors;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Vehicular Technology Conference (VTC Fall), 2014 IEEE 80th
Conference_Location :
Vancouver, BC
Type :
conf
DOI :
10.1109/VTCFall.2014.6966023
Filename :
6966023
Link To Document :
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