Date Added: May 2012
Best relay selection is a bandwidth efficient technique for multiple relay environments without compromising the system performance. The problem of relay selection is more challenging in underlay cognitive networks due to strict interference constraints to the primary users. Generally, relay selection is done on the basis of maximum end-to-end Signal to Noise Ratio (SNR). However, it requires large amounts of Channel State Information (CSI) at different network nodes. In this paper, the authors present and analyze a reactive relay selection scheme in underlay cognitive networks where the relays are operating with fixed gains near a primary user.