tailieunhanh - Báo cáo hóa học: " Adaptive antenna selection and Tx/Rx beamforming for large-scale MIMO systems in 60 GHz channels"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Adaptive antenna selection and Tx/Rx beamforming for large-scale MIMO systems in 60 GHz channels | Dong et al. EURASIP Journal on Wireless Communications and Networking 2011 2011 59 http content 2011 1 59 o EURASIP Journal on Wireless Communications and Networking a SpringerOpen Journal RESEARCH Open Access Adaptive antenna selection and Tx Rx beamforming for large-scale MIMO systems in 60 GHz channels Ke Dong1 Narayan Prasad2 Xiaodong Wang3 and Shihua Zhu1 Abstract We consider a large-scale MIMO system operating in the 60 GHz band employing beamforming for high-speed data transmission. We assume that the number of RF chains is smaller than the number of antennas which motivates the use of antenna selection to exploit the beamforming gain afforded by the large-scale antenna array. However the system constraint that at the receiver only a linear combination of the receive antenna outputs is available which together with the large dimension of the MIMO system makes it challenging to devise an efficient antenna selection algorithm. By exploiting the strong line-of-sight property of the 60 GHz channels we propose an iterative antenna selection algorithm based on discrete stochastic approximation that can quickly lock onto a near-optimal antenna subset. Moreover given a selected antenna subset we propose an adaptive transmit and receive beamforming algorithm based on the stochastic gradient method that makes use of a low-rate feedback channel to inform the transmitter about the selected beams. Simulation results show that both the proposed antenna selection and the adaptive beamforming techniques exhibit fast convergence and near-optimal performance. Keywords 60 GHz communication MIMO Antenna selection Stochastic approximation Gerschgorin circle Beamforming Stochastic gradient 1 Introduction The 60 GHz millimeter wave communication has received significant recent attention and it is considered as a promising technology for short-range broadband wireless transmission with data rate up to multi-giga bits s 1-4 . Wireless communications around .