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EURASIP Journal on Advances in Signal Processing

, 2017:37

First Online: 25 May 2017Received: 22 November 2016Accepted: 09 May 2017DOI: 10.1186-s13634-017-0474-z

Cite this article as: Yahampath, P. EURASIP J. Adv. Signal Process. 2017 2017: 37. doi:10.1186-s13634-017-0474-z

Abstract

Consider communicating a correlated Gaussian source over a Rayleigh fading channel with no knowledge of the channel signal-to-noise ratio CSNR at the transmitter. In this case, a digital system cannot be optimal for a range of CSNRs. Analog transmission however is optimal at all CSNRs, if the source and channel are memoryless and bandwidth matched. This paper presents new hybrid digital-analog HDA systems for sources with memory and channels with bandwidth expansion, which outperform both digital-only and analog-only systems over a wide range of CSNRs. The digital part is either a predictive quantizer or a transform code, used to achieve a coding gain. Analog part uses linear encoding to transmit the quantization error which improves the performance under CSNR variations. The hybrid encoder is optimized to achieve the minimum AMMSE average minimum mean square error over the CSNR distribution. To this end, analytical expressions are derived for the AMMSE of asymptotically optimal systems. It is shown that the outage CSNR of the channel code and the analog-digital power allocation must be jointly optimized to achieve the minimum AMMSE. In the case of HDA predictive quantization, a simple algorithm is presented to solve the optimization problem. Experimental results are presented for both Gauss-Markov sources and speech signals.

KeywordsHybrid digital-analog coding Predictive quantization Transform coding Fading channels Speech coding 



Author: Pradeepa Yahampath

Source: https://link.springer.com/







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