PROJECT TITLE :

Approximate closed-form power allocation scheme for multiple-input–multiple-output hybrid automatic repeat request protocols over Rayleigh block fading channels

ABSTRACT:

During this study, the outage-limited optimal power allocation problem for hybrid automatic repeat request (HARQ) protocol over multiple-input-multiple-output (MIMO) block Rayleigh fading channels is addressed. Considering 3 typical HARQ protocols, the authors first derive the approximate outage possibilities of the MIMO HARQ protocols at the high signal-to-noise ratio region. On the premise of the approximations, they then formulate an optimisation problem of minimising the typical total power usage with the constraints of the targeted outage probability and the utmost range of transmission rounds. A closed-form optimal power sequence is obtained by solving the outage-restricted optimisation drawback. Applying the solutions, the monotonicity of the optimal power sequence is additional investigated. It is found that the optimal power sequence is monotonically increasing when the targeted outage probability is smaller than a threshold. They also study the impacts of the system parameters on the optimal power sequence and the power allocation gain under numerous conditions. Finally, the numerical and simulation results are presented to verify the theoretical derivation.