Title :
Joint Beamforming and Power Control for MIMO Relay Broadcast Channel with QoS Constraints
Author :
Zhang, Rui ; Chai, Chin Choy ; Liang, Ying Chang
Author_Institution :
Inst. for Infocomm Res., Singapore
Abstract :
This paper considers the two-hop relay broadcast channel (BC) in a wireless cellular network where the downlink transmission from the base station (BS) to mobile users is assisted by a fixed relay station (RS). Assuming both the BS and RS equipped with multi-antennas, we consider joint optimization of beamforming weights and power allocations at the BS and RS so as to minimize their weighted sum-power consumption under the minimum signal-to-interference-noise-ratio (SINR) constraints at user terminals. We extend the two well-known criteria for design of linear precoding in the conventional MIMO-BC without relay, namely, the SINR balancing and the channel-inversion, to the MIMO relay BC. First, an iterative SINR-balancing algorithm is proposed that in each iteration optimizes transmit parameters at one station (BS or RS) with those at the other fixed. Secondly, a joint BS and RS channel-inversion algorithm is proposed together with a novel technique termed "eigenmode switching" at the RS. Simulation results show that optimized joint beamforming and power control are able to achieve substantial power savings for the MIMO relay BC.
Keywords :
MIMO communication; broadcast channels; cellular radio; iterative methods; power control; quality of service; relays; telecommunication control; telecommunication switching; MIMO relay broadcast channel; QoS constraints; beamforming; channel-inversion algorithm; downlink transmission; eigenmode switching; fixed relay station; iterative SINR-balancing algorithm; linear precoding; mobile users; power allocations; power control; signal-to-interference-noise-ratio constraints; two-hop relay broadcast channel; wireless cellular network; Array signal processing; Base stations; Broadcasting; Downlink; Iterative algorithms; Land mobile radio cellular systems; MIMO; Power control; Relays; Signal to noise ratio;
Conference_Titel :
Signals, Systems and Computers, 2007. ACSSC 2007. Conference Record of the Forty-First Asilomar Conference on
Conference_Location :
Pacific Grove, CA
Print_ISBN :
978-1-4244-2109-1
Electronic_ISBN :
1058-6393
DOI :
10.1109/ACSSC.2007.4487251