An Optimal Algorithm for Relay Node Assignment in Cooperative Ad Hoc Networks

Dept. of Comput. Sci., Virginia Polytech. Inst. & State Univ., Blacksburg, VA, USA
IEEE/ACM Transactions on Networking (Impact Factor: 1.99). 07/2011; 19(3):879 - 892. DOI: 10.1109/TNET.2010.2091148
Source: IEEE Xplore

ABSTRACT Recently, cooperative communications, in the form of having each node equipped with a single antenna and exploit spatial diversity via some relay node's antenna, is shown to be a promising approach to increase data rates in wireless networks. Under this communication paradigm, the choice of a relay node (among a set of available relay nodes) is critical in the overall network performance. In this paper, we study the relay node assignment problem in a cooperative ad hoc network environment, where multiple source-destination pairs compete for the same pool of relay nodes in the network. Our objective is to assign the available relay nodes to different source-destination pairs so as to maximize the minimum data rate among all pairs. The main contribution of this paper is the development of an optimal polynomial time algorithm, called ORA, that achieves this objective. A novel idea in this algorithm is a “linear marking” mechanism, which maintains linear complexity of each iteration. We give a formal proof of optimality for ORA and use numerical results to demonstrate its capability.

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Available from: Yi Shi, Aug 28, 2015
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    • "Following our network model and the discussions in [20] and [32], each source-destination pair can use either direct transmission or cooperative communication with the help of the best relay to achieve full diversity. We define the channel between s i and d i (with or without cooperative relay) as primary channel, and the channel between s i and e u (with or without cooperative relay) as eavesdropping channel. "
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    • "In this case, S does not require to retransmit any packets while R 1 , R 2 and R 3 need to retransmit {s[2], s[6]}, {s[3], s[6]} and {s[2], s[3], s[5] "
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    • "The theoretical analyses performed in several studies, e.g., [2], show that the choice of proper RN(s) to serve a certain UE, or a group of UEs, is of critical importance for achieving the expected performances of cooperative transmissions. In [11] it is proposed an optimal relay assignment algorithm for ad-hoc networks based on the maximization of the minimum rate for all source-destination node pairs. The algorithm does not have a unique solution and it optimizes only the performance of the worst user. "
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