Approximations of the packet error rate under quasi-static fading in direct and relayed links
Paul Ferrand, Jean-Marie Gorce, Claire Goursaud · EURASIP Journal on Wireless Communications and Networking · 2015
The packet error rate (PER) is a metric of choice to compute the practical performance of communication systems experiencing block fading , e.g., fading processes whose coherence time is relatively slow when compared to the symbol transmission rate. For these types of channels, we derive a closed-form asymptotic expression which approximates the value of the PER for high signal-to-noise ratio (SNR). We also provide another approximation based on a unit-step formulation of the symbol error rate (SER). We show that the two approximations are related and may be derived from one another, thereby allowing us to obtain closed-form approximations of the block fading PER in both coded and uncoded systems. We then show how these approximations may be used in practice, through the derivation of a packet error outage (PEO) metric covering the case where the links experience shadowing on top of block fading, as well as asymptotically optimal power allocations in relay channels under a block fading hypothesis.