Effective Capacity and Power Allocation for Machine-Type Communication

Effective capacity (EC) determines the maximum communication rate subject to a particular delay constraint. In this paper, we analyze the EC of ultra reliable machine type communication networks operating in the finite blocklength regime. First, we present a closed form approximation for EC in quasi-static Rayleigh fading channels. Our analysis determines the upper bounds for EC and delay constraint when varying transmission power. Finally, we characterize the power-delay tradeoff for fixed EC and propose an optimum power allocation scheme which exploits the asymptotic behavior of EC in the high SNR regime. The results illustrate that the proposed scheme provides significant power saving with a negligible loss in EC.