A Unified Approach to Hybrid Coding

This paper investigates the problem of secret key generation over a wiretap channel when the terminals observe correlated sources. These sources may or may not be independent of the main channel and the users overhear them before the transmission takes place. A novel achievable scheme for the case of independent sources is proposed, and it is shown to be optimal under certain less noisy conditions. This result improves upon the existing literature where the more stringent condition of degradedness was needed. For the situation where the sources are correlated with the main channel, a second achievable scheme based on joint source-channel coding is introduced, for which special cases of binary and Gaussian channels are studied. Some optimality results are derived, however, these are much less general than for the first setup.

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“…Proof: This lemma can be proved using similar steps as [34,Lemma 1]. See Appendix C-B below for details.…”

Section: A Upper Bound On the Probability Of Errormentioning

confidence: 99%

“…However, in the proposed joint coding scheme, the transmitted indices depend on the actual codebook. In the following, we upper bound the error probability of the joint decoding by following similar arguments to those in [18], [33], [34].…”

Section: Appendix C Error Probability Of Joint Decodingmentioning

confidence: 99%

Secret key generation over noisy channels with common randomness

Bassi¹,

Piantanida²,

Shamai³

2016

2016 IEEE International Symposium on Information Theory (ISIT)

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“…= w M = 1, claims (i)-(ii) may not hold if we insist on exact independence. This issue has been dealt with in [21][22][23], and following similar arguments, one can show that (i) and (ii) hold with "almost independence". The probability of the considered error event is thus arbitrarily close to zero for large enough n if:…”

Section: Appendix a Analysis Of The Achievable Schemementioning

confidence: 88%

Capacity Bounds on the Downlink of Symmetric, Multi-Relay, Single-Receiver C-RAN Networks

Bidokhti

Kramer

Shamai

2017

Entropy

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Abstract:The downlink of symmetric Cloud Radio Access Networks (C-RANs) with multiple relays and a single receiver is studied. Lower and upper bounds are derived on the capacity. The lower bound is achieved by Marton's coding, which facilitates dependence among the multiple-access channel inputs. The upper bound uses Ozarow's technique to augment the system with an auxiliary random variable. The bounds are studied over scalar Gaussian C-RANs and are shown to meet and characterize the capacity for interesting regimes of operation.

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“…A general HDA scheme is studied in [30] in the absence of side information for static channels. The necessary conditions on the achievable distortion are derived based on auxiliary random variables, by accounting for the correlation in the indexes of source and channel codebooks.…”

Section: F Superposed Hybrid Digital-analog Transmission (S-hda)mentioning

confidence: 99%

“…In our setup, the side information, i.e., T n = γ c S n + Z n , can be modeled as a channel output correponding to input S n . Then, it follows from [30] that a distortion D h is achievable if…”

Section: F Superposed Hybrid Digital-analog Transmission (S-hda)mentioning

confidence: 99%

Joint Source-Channel Coding With Time-Varying Channel and Side-Information

Aguerri

Gündüz

2016

IEEE Trans. Inform. Theory

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Abstract-Transmission of a Gaussian source over a timevarying Gaussian channel is studied in the presence of timevarying correlated side information at the receiver. A block fading model is considered for both the channel and the side information, whose states are assumed to be known only at the receiver. The optimality of separate source and channel coding in terms of average end-to-end distortion is shown when the channel is static while the side information state follows a discrete or a continuous and quasiconcave distribution. When both the channel and side information states are time-varying, separate source and channel coding is suboptimal in general. A partially informed encoder lower bound is studied by providing the channel state information to the encoder. Several achievable transmission schemes are proposed based on uncoded transmission, separate source and channel coding, joint decoding as well as hybrid digital-analog transmission. Uncoded transmission is shown to be optimal for a class of continuous and quasiconcave side information state distributions, while the channel gain may have an arbitrary distribution. To the best of our knowledge, this is the first example in which the uncoded transmission achieves the optimal performance thanks to the time-varying nature of the states, while it is suboptimal in the static version of the same problem. Then, the optimal distortion exponent, that quantifies the exponential decay rate of the expected distortion in the high SNR regime, is characterized for Nakagami distributed channel and side information states, and it is shown to be achieved by hybrid digital-analog and joint decoding schemes in certain cases, illustrating the suboptimality of pure digital or analog transmission in general.Index Terms-Distortion exponent, joint source-channel coding, fading channel and side information, side information diversity, uncoded transmission, hybrid digital-analog transmission, joint decoding.

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A Unified Approach to Hybrid Coding

Cited by 75 publications

References 66 publications

Secret key generation over noisy channels with common randomness

Secret key generation over noisy channels with common randomness

Capacity Bounds on the Downlink of Symmetric, Multi-Relay, Single-Receiver C-RAN Networks

Joint Source-Channel Coding With Time-Varying Channel and Side-Information

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