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arXiv · 0704.2651

Opportunistic Communications in an Orthogonal Multiaccess Relay Channel

Lalitha Sankar·Yingbin Liang·H. Vincent Poor·Narayan B. Mandayam
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Abstract

The problem of resource allocation is studied for a two-user fading orthogonal multiaccess relay channel (MARC) where both users (sources) communicate with a destination in the presence of a relay. A half-duplex relay is considered that transmits on a channel orthogonal to that used by the sources. The instantaneous fading state between every transmit-receive pair in this network is assumed to be known at both the transmitter and receiver. Under an average power constraint at each source and the relay, the sum-rate for the achievable strategy of decode-and-forward (DF) is maximized over all power allocations (policies) at the sources and relay. It is shown that the sum-rate maximizing policy exploits the multiuser fading diversity to reveal the optimality of opportunistic channel use by each user. A geometric interpretation of the optimal power policy is also presented.

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Lalitha Sankar, Yingbin Liang, H. Vincent Poor, Narayan B. Mandayam. 2007-04-20. Opportunistic Communications in an Orthogonal Multiaccess Relay Channel. https://doi.org/10.1109/isit.2007.4557396

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