Approximate Performance Analysis of the Incremental Relaying Protocol and Modification

The incremental relaying (IR) protocol outperforms simple amplify-and-forward and decode-and-forward protocols due to usage of feedback. Based on the IR protocol, a novel protocol termed as fractional incremental relaying (FIR) is firstly presented in this paper to achieve higher spectral efficiency. When a packet of data needs to be transmitted by the relay node, symbols are transmitted a few at a time as needed instead of the entire packet. Then, analysis result shows that the proposed protocol makes more efficient use of channel freedom degrees than the traditional IR protocol does. Finally, numerical results under independent Rayleigh fading demonstrate the advantage of the proposed FIR protocol.