On the Joint Optimal Power Allocation for DF Relaying and Beamforming Communication Systems

Feng LU  Chen LIU  Hua-An ZHAO  

IEICE TRANSACTIONS on Communications   Vol.E95-B   No.3   pp.889-897
Publication Date: 2012/03/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E95.B.889
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
OFDM relaying networks,  power allocation (PA),  decode-and-forward (DF),  beamforming,  

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This paper considers the power allocation (PA) problem for three-node decode-and-forward (DF) relay communication systems, where the aggregate transmit power constraint is imposed on the source and the relay and the optimization target is to maximize the system's instantaneous information rate. Since the relay is equipped with multiple antennas, the receiver and transmitter beamforming strategies are generally adopted. In this paper, we start by proposing a closed-form solution for the frequency-flat (FF) fading environment, then give a bisection algorithm with low complexity to obtain an optimal solution for the frequency-selective (FS) fading scenario. Finally, simulations validate the proposed methods.