Low complexity power optimization algorithm for multimedia transmission over wireless networks

This paper considers the problem of transmit power optimization for multimedia applications in continuous high-speed transmission over wireless networks. The power optimization process is developed by noting that some performance metrics such as throughput, delay and peak signal-to-noise ratio (PSNR) for particular systems with hybrid automatic repeat request (HARQ) may exhibit a staircase behavior. In such scenarios, the corresponding metric remains fixed for a wide range of signal-to-noise ratios (SNRs). Consequently, the transmit power can be reduced significantly while the relevant metric remains almost unchanged. The obtained results reveal that invoking power optimization algorithms can achieve a significant power saving of about 80% for particular scenarios. The system considered in this work is a truncated HARQ with turbo product codes (TPC) and parallel concatenated convolutional codes (PCCC). Chase combining is also used to combine the retransmitted packets with the original transmission. An efficient semi-analytical model is developed to obtain the system throughput in additive white Gaussian noise (AWGN) and Rayleigh fading channels. The obtained results also show that using the throughput, delay or PSNR as performance metrics provides equivalent power saving results.