On Improving the BLER for ML Receivers in Block Faded Channels through Random Phase Rotation

摘要

In this work, we apply the idea of random phase rotation of the modulated symbols to a system with interfering transmitters and a Maximum-likelihood (ML) receiver. Expressions for Bit Error Rate (BER) for a given channel realization and the average Block Error Rate (BLER) for an error correcting code are derived for the Hard-Decision based ML receiver (HDML). The derived expressions are verified through simulation results and it is observed that at high signal to noise ratio (SNR), when the channel is quasi-static (block fading), random phase rotation provides a gain in BLER when compared to the case without random phase rotation. Also it is observed that the BLER for a system with random phase rotation approaches the BLER for the case of no co-channel interference. The gain due to random phase rotation is also verified for an LTE framework with Soft-Decision based ML receiver (SD-ML).