Power and resource allocation for orthogonal multiple access relay systems

Abstract

We study the problem of joint power and channel resource allocation for orthogonal multiple access relay (MAR) systems in order to maximize the achievable rate region. Four relaying strategies are considered; namely, regenerative decode-and-forward (RDF), nonregenerative decode-and-forward (NDF), amplify-and-forward (AF), and compress-and-forward (CF). For RDF and NDF we show that the problem can be formulated as a quasiconvex problem, while for AF and CF we show that the problem can be made quasiconvex if the signal-to-noise ratios of the direct channels are at least −3 dB. Therefore, efficient algorithms can be used to obtain the jointly optimal power and channel resource allocation. Furthermore, we show that the convex subproblems in those algorithms admit a closed-form solution. Our numerical results show that the joint allocation of power and the channel resource achieves significantly larger achievable rate regions than those achieved by power allocation alone with fixed channel resource allocation. We also demonstrate that assigning different relaying strategies to different users together with the joint allocation of power and the channel resources can further enlarge the achievable rate region.

DF-based sum-rate optimization for multicarrier multiple access relay channel

“…They also investigate a problem of subcarrier assignment for given powers at the sources and the relay. The reader may also refer to [22][23][24] for some related works.…”

“…The authors show that the sum-rate belongs to one of the different cases and they optimize the power allocation in order to maximize the sum-rate for all the cases. In comparison with our setting, their relay uses non-regenerative DF [22] where it transmits, during the second transmission period, to the destination a codeword independent from the ones transmitted by the sources. However, in our setting, the relay estimates the symbols sent by the sources and then forwards them to the destination, i.e., the relay implements regenerative DF [22] in which the relay uses the same codebook as that used by the sources, and thus, it transmits the same codewords as those sent by the sources.…”

Opportunistic Communications in an Orthogonal Multiaccess Relay Channel

“…October 25, 2018 DRAFT where ν k , for all k = 1, 2, r, are dual variables associated with the power constraints in (23). Specializing the KKT conditions for each case, we obtain the optimal policies for each case as summarized below following which we list the conditions that the optimal policy for each case needs to satisfy.…”

“…Resource allocation in multiuser relay networks has been studied recently in [23]- [25]. The authors in [23] and [25] consider a specific orthogonal model where the sources time-duplex their transmissions and are aided in their transmissions by a half-duplex relay, while in [24] the optimal multiuser scheduling is determined under the assumption of a non-fading backhaul channel between the relay and destination.…”

Capacity Analysis of Opportunistic Cooperative Networks under Adaptive Transmission over Rayleigh Fading Channels

“…Recently, optimum resource allocation has emerged as an important research topic to improve the performance of cooperative networks (e.g., see [13][14][15][16][17]). Most of the above mentioned studies, however, focus on the optimum power allocation and/or relay location optimization with assumption that accurate channel state information (CSI) of all links in the network are available at each node.…”