In this paper we discuss the application of a joint source-channel decoding approach to image transmission over wireless channels. In addition to channel codes, also the implicit residual redundancy after source encod...
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ISBN:
(纸本)0780374029
In this paper we discuss the application of a joint source-channel decoding approach to image transmission over wireless channels. In addition to channel codes, also the implicit residual redundancy after source encoding in both horizontal and vertical direction is utilized for error protection. At the decoder we use an iterative ("turbo") source-channel decoder which can be obtained in the same manner as for serially concatenated channel codes. As a new result we show that this iterative decoding scheme in combination with a novel simplified joint source and channelcoding rate allocation at the encoder can be successfully employed for protecting the image data, especially when the channel is highly corrupted. Furthermore, when the source correlations are approximated with a large training set at the decoder, only a small loss in performance is observed.
We introduce deep learning based communication methods for successive refinement of images over wireless channels. We present three different strategies for progressive image transmission with deep JSCC, with differen...
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ISBN:
(纸本)9781538665282
We introduce deep learning based communication methods for successive refinement of images over wireless channels. We present three different strategies for progressive image transmission with deep JSCC, with different complexity-performance tradeoffs, all based on convolutional autoencoders. Numerical results show that deep JSCC not only provides graceful degradation with channel signal-to-noise ratio (SNR) and improved performance in low SNR and low bandwidth regimes compared to state-of-the-art digital communication techniques, but can also successfully learn a layered representation, achieving performance close to a single-layer scheme. These results suggest that natural images encoded with deep JSCC over Gaussian channels are almost successively refinable.
Wireless data gathering networks are often tasked to gather correlated data under severe energy constraints. The use of simple channel codes with source-channel decoding can potentially provide good performance with l...
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ISBN:
(纸本)9781424492688
Wireless data gathering networks are often tasked to gather correlated data under severe energy constraints. The use of simple channel codes with source-channel decoding can potentially provide good performance with low energy consumption. Here we consider progressive coding in multi-hop networks, where an intermediate node decodes its received noisy codewords. The estimated information is concatenated with the node's own information word and encoded;the resulting progressively-encoded codeword is then transmitted to the next node. In non-progressive coding, the node simply forwards the received noisy codewords along with its own encoded data. Here we compare the performance of two codes with low decoding complexity, Repeat-Accumulate (RA) and Low-Density Parity-Check (LDPC) codes, in combination with two progressive coding schemes. Progressive channelcoding uses only channel decoding at the intermediate node, while progressive source-channelcoding uses source-channel decoding, exploiting the probabilistic dependency of the information words (caused by the correlation structure of the data) jointly with the deterministic dependency induced by channelcoding. Two decoding schemes are considered at the data center: channel decoding only and iterative source-channel decoding. In simulation experiments, we consider a line network topology with systematic RA and LDPC coding. Results show that progressive coding performs better than non-progressive coding, and RA codes perform better with lower computational complexity than LDPC codes, both for channel-decoding-only and iterative source-channel decoding.
The problem of lossless joint source-channelcoding for the two-way relay network with an orthogonal multiple access channel is studied. Necessary and sufficient conditions for reliable communication are given, and a ...
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ISBN:
(纸本)9780769543529
The problem of lossless joint source-channelcoding for the two-way relay network with an orthogonal multiple access channel is studied. Necessary and sufficient conditions for reliable communication are given, and a separation theorem for source and channelcoding is proved.
Motivated by the practical requirement for delay and complexity constrained broadcasting, we study uncoded transmission of a pair of correlated Gaussian sources over a two-user Gaussian broadcast channel with unit-del...
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ISBN:
(纸本)9781479970889
Motivated by the practical requirement for delay and complexity constrained broadcasting, we study uncoded transmission of a pair of correlated Gaussian sources over a two-user Gaussian broadcast channel with unit-delay noiseless feedback links (GBCF). Differently from previous works, in the present work we focus on the finite horizon regime. We present two joint source-channelcoding schemes, one is based on the Ozarow-Leung (OL) coding scheme for the GBCF and the other is based on the linear quadratic Gaussian (LQG) code by Ardestanizadeh et al. Our LQG-oriented code uses an improved decoder which outperforms the original decoder of Ardestanizadeh et al. in the finite horizon regime. We further derive lower and upper bounds on the minimal number of channel uses needed to achieve a specified pair of distortion levels for each scheme, and using these bounds, we explicitly characterize a range of transmit powers in which the OL code outperforms the LOG-oriented code.
We address distributed sourcecoding with decoder side information, when the decoder observes the source through a noisy channel. Existing approaches employ syndrome- or parity-based channel codes. We propose a new ap...
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ISBN:
(纸本)9781424479948
We address distributed sourcecoding with decoder side information, when the decoder observes the source through a noisy channel. Existing approaches employ syndrome- or parity-based channel codes. We propose a new approach based on distributed arithmetic coding (DAC). We introduce a DAC with forbidden symbol, which allows to tune the redundancy according to the amount of channel noise. We propose a novel sequential decoder that employs the known side information to decode the corrupted codeword. Experimental results show that the proposed scheme is better than parity-based turbo codes at relatively short block lengths.
We consider the case of two correlated binary information sequences. Instead of compressing the information using sourcecoding, both sequences are independently channel encoded, and transmitted over an AWGN channel. ...
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ISBN:
(纸本)0769510310
We consider the case of two correlated binary information sequences. Instead of compressing the information using sourcecoding, both sequences are independently channel encoded, and transmitted over an AWGN channel. The correlation between both sequences is exploited at the receiver, allowing reliable communications at signal to noise ratios very close to the theoretical limits established by the combination of Shannon and Slepian-Wolf theorems.
This paper investigates the design of optimal vector quantization given channel and error statistics by inclusion of cyclic redundancy checks (CRC) into the consideration. Given a broadcast system with multiresolution...
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ISBN:
(纸本)9781479904464
This paper investigates the design of optimal vector quantization given channel and error statistics by inclusion of cyclic redundancy checks (CRC) into the consideration. Given a broadcast system with multiresolution vector quantization (MRVQ) and error detection availability for each resolution, a closed-form formula for the weighted end-to-end distortion (EED) is first derived under a random index assignment. Based on the closed-form formula, an iterative algorithm is then proposed for designing optimal MRVQ to minimize the EED with CRC. Experiments show that for a wide range of channel error probability, the inclusion of CRC indeed reduces the EED. Finally, the best tradeoff between the number of bits for quantization and those for CRC is also investigated by experiments.
In this work, the MAP source-controlled channel decoder with matched and mismatched source transition probability matrix (STPM) is intensively examined for a MPEG-4 video sequence. We attempt to answer whether or not ...
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ISBN:
(纸本)9781467355803;9781467355780
In this work, the MAP source-controlled channel decoder with matched and mismatched source transition probability matrix (STPM) is intensively examined for a MPEG-4 video sequence. We attempt to answer whether or not one can use the MAP decoding with a mismatched STPM instead of the MAP decoding with the matched STPM. The matched STPM requires the transmission for every frame images. Here, the commonly " foreman" video input is extracted into 300 frame images. Each image is inserted into the MPEG-4 image transmission system over the Nakagami-m, block-fading channels with rn. = 1.5 2.0 and 2.5. The system performance in in term of the peak signal to noise ratio (PSNR) and word error rate (WER) are summarized at 'b = 3.75 and 5 dB. The results from both MAP decoding with matched STMP and mismatched STMP show the similarity of the system performance. Moreover, the slight improvement is obtained when MAP decoder is compared with ML decoder.
We propose a new code design for compress-and-forward relaying over bandlimited relay-to-destination channels. The main contribution of this paper is a code design based on joint (source-channel) coding and modulation...
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ISBN:
(纸本)9781612842547
We propose a new code design for compress-and-forward relaying over bandlimited relay-to-destination channels. The main contribution of this paper is a code design based on joint (source-channel) coding and modulation that uses the correlation between the observations at the relay and the destination as protection against channel errors. This allows for relay nodes with reduced complexity, shifting most of the processing requirements to the destination node. Moreover, by using scalar quantizers with an entropy constraint our system provides remarkable performance in channel conditions where neither amplify-and-forward nor compress-and-forward efficiently exploit the presence of a relay node. Simulation results confirm the benefits of our proposed system.
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