2013/12/03 by Iñaki Estella Aguerri, Aguerri, Iñaki Estella, Denız Gündüz +1
Computer Science · Engineering · #Cooperative Communication and Network Coding #Energy Harvesting in Wireless Networks #FOS: Computer and information sciences #Information Theory (cs.IT) #Wireless Communication Security Techniques
paper · pdf · doi:10.48550/arxiv.1312.0932
openalex publication_date 2013/12/03 · openalex created_date 2022/10/05 · openalex updated_date 2026/07/28
Transmission of a Gaussian source over a time-varying Gaussian channel is\nstudied in the presence of time-varying correlated side information at the\nreceiver. A block fading model is considered for both the channel and the side\ninformation, whose states are assumed to be known only at the receiver. The\noptimality of separate source and channel coding in terms of average end-to-end\ndistortion is shown when the channel is static while the side information state\nfollows a discrete or a continuous and quasiconcave distribution. When both the\nchannel and side information states are time-varying, separate source and\nchannel coding is suboptimal in general. A partially informed encoder lower\nbound is studied by providing the channel state information to the encoder.\nSeveral achievable transmission schemes are proposed based on uncoded\ntransmission, separate source and channel coding, joint decoding as well as\nhybrid digital-analog transmission. Uncoded transmission is shown to be optimal\nfor a class of continuous and quasiconcave side information state\ndistributions, while the channel gain may have an arbitrary distribution. To\nthe best of our knowledge, this is the first example in which the uncoded\ntransmission achieves the optimal performance thanks to the time-varying nature\nof the states, while it is suboptimal in the static version of the same\nproblem. Then, the optimal \distortion exponent, that quantifies the\nexponential decay rate of the expected distortion in the high SNR regime, is\ncharacterized for Nakagami distributed channel and side information states, and\nit is shown to be achieved by hybrid digital-analog and joint decoding schemes\nin certain cases, illustrating the suboptimality of pure digital or analog\ntransmission in general.\n