Impact of M-ary Data Symbol Burst Transmission on Averaged Channel Capacity for ADF Relay Systems

In this paper, we consider M-ary phase shifting keying (MPSK) and M-ary quadrature amplitude modulation (MQAM) data symbol burst transmission for adaptive decode-andforward (ADF) relay systems over quasi-static Rayleigh fading channels. A burst has pilot symbols and data symbols. From pilot symbols, we can estimate the channel gain and detect each relay node’s transmission mode for ADF schemes. At first, we focus on the derivation of the received signal to noise ratio’s (SNR’s) probability density function (PDF) for ADF relay systems, in which error events at relay nodes and channel estimation errors are considered. Then, we derived the averaged channel capacity as an approximated closed-form for an arbitrary link signal-to-noise ratio (SNR) for different modulation orders. We verified its accuracy by comparison with simulation results.