N Plus Normalized Threshold Opportunistic Relay Selection With Outdated Channel State Information
Cooperative communication has been demonstrated to be an effective way to combat wireless fading by providing spatial diversity without the need of multi-antenna configurations. In a cooperative network, multiple relays work as intermediate conduits to enable different spatial paths for relaying information. However, with the use of orthogonal channels, the overall system rate will decrease as the number of relays increases. This problem can be avoided by the use of Relay Selection (RS). According to the number of relays involved in the cooperation, the RS schemes can generally be classified into two categories: Single-RS (SRS) and Multiple-RS (MRS) schemes.