Packet-wise AF and Incremental AF performance optimization for uplink CDMA communications

In this paper, we propose a novel optimization approach for Amplify-and-Forward (AF) relaying schemes. In previous works, we have optimized the AF relaying scheme carried on a symbol-by-symbol basis. Here, we focus on AF and Incremental AF (IAF) schemes, operating on a packet-by-packet basis. The optimization is carried out while keeping the additional multiple access interference cost, inherent to relaying, constant. For CDMA uplink communications, this cost can reliably quantify the capacity loss incurred by the use of relaying in the transmission process. We define an optimization cost constraint and propose an approach to optimize AF and IAF relaying performance in terms of Block-Error-Rate (BLER). In order to assess the performance enhancement over direct transmission of optimized relaying schemes and compare AF and IAF, we have carried numerous simulations results.