tailieunhanh - Báo cáo hóa học: " Research Article Uplink SDMA with Limited Feedback: Throughput Scaling"

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: Research Article Uplink SDMA with Limited Feedback: Throughput Scaling | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2008 Article ID 479357 17 pages doi 2008 479357 Research Article Uplink SDMA with Limited Feedback Throughput Scaling Kaibin Huang Robert W. Heath Jr. and Jeffrey G. Andrews Wireless Networking and Communications Group Department of Electrical and Computer Engineering The University of Texas at Austin Austin TX 78712-0240 USA Correspondence should be addressed to Kaibin Huang huangkb@ Received 15 June 2007 Accepted 23 October 2007 Recommended by Christoph F. Mecklenbrauker Combined space division multiple access SDMA and scheduling exploit both spatial multiplexing and multiuser diversity increasing throughput significantly. Both SDMA and scheduling require feedback of multiuser channel sate information CSI . This paper focuses on uplink SDMA with limited feedback which refers to efficient techniques for CSI quantization and feedback. To quantify the throughput of uplink SDMA and derive design guidelines the throughput scaling with system parameters is analyzed. The specific parameters considered include the numbers of users antennas and feedback bits. Furthermore different SNR regimes and beamforming methods are considered. The derived throughput scaling laws are observed to change for different SNR regimes. For instance the throughput scales logarithmically with the number of users in the high SNR regime but double logarithmically in the low SNR regime. The analysis of throughput scaling suggests guidelines for scheduling in uplink SDMA. For example to maximize throughput scaling scheduling should use the criterion of minimum quantization errors for the high SNR regime and maximum channel power for the low SNR regime. Copyright 2008 Kaibin Huang et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly .