DocumentCode :
1051786
Title :
Quality of Service and Max-Min Fair Transmit Beamforming to Multiple Cochannel Multicast Groups
Author :
Karipidis, Eleftherios ; Sidiropoulos, Nicholas D. ; Luo, Zhi-Quan
Author_Institution :
Tech. Univ. of Crete, Chania
Volume :
56
Issue :
3
fYear :
2008
fDate :
3/1/2008 12:00:00 AM
Firstpage :
1268
Lastpage :
1279
Abstract :
The problem of transmit beamforming to multiple cochannel multicast groups is considered, when the channel state is known at the transmitter and from two viewpoints: minimizing total transmission power while guaranteeing a prescribed minimum signal-to-interference-plus-noise ratio (SINR) at each receiver; and a "fair" approach maximizing the overall minimum SINR under a total power budget. The core problem is a multicast generalization of the multiuser downlink beamforming problem; the difference is that each transmitted stream is directed to multiple receivers, each with its own channel. Such generalization is relevant and timely, e.g., in the context of the emerging WiMAX and UMTS-LTE wireless networks. The joint problem also contains single-group multicast beamforming as a special case. The latter (and therefore also the former) is NP-hard. This motivates the pursuit of computationally efficient quasi-optimal solutions. It is shown that Lagrangian relaxation coupled with suitable randomization/cochannel multicast power control yield computationally efficient high-quality approximate solutions. For a significant fraction of problem instances, the solutions generated this way are exactly optimal. Extensive numerical results using both simulated and measured wireless channels are presented to corroborate our main findings.
Keywords :
minimax techniques; multicast communication; multiuser channels; quality of service; wireless channels; Lagrangian relaxation; UMTS-LTE wireless networks; WiMax; max-min technique; multiple cochannel multicast groups; multiuser downlink beamforming; quality of service; signal-to-interference-plus-noise ratio; total transmission power minimization; transmit beamforming; wireless channel; Broadcasting; convex optimization; downlink beamforming; multicasting; semidefinite relaxation;
fLanguage :
English
Journal_Title :
Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1053-587X
Type :
jour
DOI :
10.1109/TSP.2007.909010
Filename :
4443878
Link To Document :
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