Quality of Service and Max-Min Fair Transmit Beamforming to Multiple Cochannel Multicast Groups

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 s...

• Type: Journal
• Year: 2008
• Where: TSP
• Authors: Eleftherios Karipidis, Nikos D. Sidiropoulos, Zhi-Quan Luo
• Keywords: Beamforming, Cochannel Multicast Groups, Multicast, TSP 2008