Energy Efficient Optimization for CC-HARQ Over Block Rayleigh Fading Channels

摘要

In this letter, the energy efficiency (EE) of Chase combining based hybrid automatic repeat request (CC-HARQ) over block Rayleigh fading channels is analyzed and optimized from a cross-layer perspective. Specifically, we derive the EE of CC-HARQ in a tractable closed-form expression using a new log-domain linear threshold approximation method. Then the optimum payload length and average transmission energy per bit are identified to maximize the EE. In addition, to achieve a flexible tradeoff between EE and spectral efficiency (SE), the unified EE-SE tradeoff metric is introduced and optimized. The analytical and simulation results verify the effectiveness of our design.