Location-Based Optimum Cooperative Relay Selection in Spatial Wireless Networks
This paper derives the performance and key structural properties of optimum location-based relay selection schemes for wireless networks consisting of spatially deployed decode-and-forward relays. For a homogeneous Poisson point process (PPP) of relays and general path-loss models, we obtain the distribution for channel quality indicator of the relay selected by the optimum location-based relay selection policy. For feedback reduction, we investigate a class of threshold-based distributed relay selection policies. For this class, we show that the total number of relays feeding back is a Poisson distributed random variable and obtain an analytical expression for the average feedback load. We derive analytical expressions for the average rate and the outage probability for the fading and no-fading scenarios with and without full feedback. As generalizations, we study the optimum relay selection problem for two other scenarios: i) isotropic Poisson point processes and ii) heterogeneous source-to-relay and relay-to-destination links. It is observed that the optimum relay selection policy outperforms the other common selection strategies notably. Further, we achieve almost the same performance with the optimum relay selection policy by only utilizing location information from a small number of relays via threshold-based distributed relay selection policies.
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