In this work, a new robust and efficient airborne synthetic aperture radar (SAR) image coding transmission scheme based on compressive sensing (CS) against lossy channels is proposed. The robustness is achieved using ...
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ISBN:
(纸本)9781479957521
In this work, a new robust and efficient airborne synthetic aperture radar (SAR) image coding transmission scheme based on compressive sensing (CS) against lossy channels is proposed. The robustness is achieved using the democracy of CS. Considering the poor R-D performance of the traditional CS due to SAR image's weak sparsity, we use directional lifting wavelet transform (DLWT) as sparse representation and sparse-filtering to eliminate the interference of small coefficients. By exploiting the inter-scale dependency of DLWT coefficients, an efficient Bayesian reconstruction algorithm is adopted. Furthermore, optimal tradeoff between bit-depth and measurement rate is used. Experimental results show that the proposed scheme is more robust against packet loss compared with the traditional joint source-channelcoding (JSCC) scheme. When the packet loss rate (PLR) is excessive, the JSCC scheme easily leads to cliff effect, however, the R-D performance of the proposed scheme decreases more gracefully while achieving a comparative R-D performance.
Since joint source-channel decoding is capable of exploiting the residual redundancy in the source signals for improving the attainable error resilience, it has attracted substantial attention. In this treatise, the a...
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Since joint source-channel decoding is capable of exploiting the residual redundancy in the source signals for improving the attainable error resilience, it has attracted substantial attention. In this treatise, the authors study iterative source-channel decoding (ISCD) aided video communications, where the video signal redundancy is modelled by a first-order Markov process. Firstly, the authors derive reduced-complexity formulas for the first-order Markov modelling (FOMM) aided source decoding. Then they propose a bit-based iterative horizontal-vertical scanline model (IHVSM) aided source decoding algorithm, where a horizontal and a vertical source decoder are employed for exchanging their extrinsic information using the iterative decoding philosophy. The iterative IHVSM aided decoder is then employed in a forward error correction (FEC) encoded uncompressed video transmission scenario, where the IHVSM and the FEC decoder exchange softbit-information for performing turbo-like ISCD for the sake of improving the reconstructed video quality. Finally, the authors benchmark the attainable system performance against a near-lossless H.264/AVC video communication system and the existing FOMM-based softbit source decoding scheme. The authors simulation results show that E-b/N-0 improvements in excess of 2.8 dB are attainable by the proposed technique in uncompressed video applications.
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 investigate the performance of analog joint sourcechannelcoding systems based on the use of spiral-like space filling curves for the transmission of Gaussian sources over non-linear channels, including channels o...
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ISBN:
(纸本)9781467352390;9781467352376
We investigate the performance of analog joint sourcechannelcoding systems based on the use of spiral-like space filling curves for the transmission of Gaussian sources over non-linear channels, including channels of the type encountered in underwater acoustic communications. We focus on bandwidth reduction schemes where two i.i.d. samples are mapped to one channel symbol. We evaluate the theoretical limits for some of the non-linear channels and extend existing analog coding schemes to deal with the channel non-linearities, demonstrating that the system performance is very close to the theoretical limits for a wide range of signal to noise ratios.
In this paper, we consider lossy source transmission over a Multiple Access WireTap channel (MAC-WT). In this model, there are two correlated sources, each of them is available at the corresponding encoder. The receiv...
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ISBN:
(纸本)9781479904464
In this paper, we consider lossy source transmission over a Multiple Access WireTap channel (MAC-WT). In this model, there are two correlated sources, each of them is available at the corresponding encoder. The receiver tries to reconstruct both sources with desired distortions. The sources should be kept secret from an eavesdropper. We propose a joint source-channel scheme for the MAC-WT. In this scheme, each source sequence is mapped to common and private codewords. The common codeword can be decoded by the eavesdropper. The private codeword needs to be kept secret from the eavesdropper by using Wyner's wiretap coding. We also discuss some special cases of the proposed scheme.
Symmetric fix-free codes are prefix condition codes in which each codeword is required to be a palindrome. Their study is motivated by the topic of joint source-channelcoding. Although they have been considered by a ...
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ISBN:
(纸本)9781467360371
Symmetric fix-free codes are prefix condition codes in which each codeword is required to be a palindrome. Their study is motivated by the topic of joint source-channelcoding. Although they have been considered by a few communities they are not well understood. In earlier work we used a collection of instances of Boolean satisfiability problems as a tool in the generation of all optimal binary symmetric fix-free codes with n codewords and observed that the number of different optimal codelength sequences grows slowly compared with the corresponding number for prefix condition codes. We demonstrate that all optimal symmetric fix-free codes can alternatively be obtained by sequences of codes generated by simple manipulations starting from one particular code. We also discuss simplifications in the process of searching for this set of codes.
The characterization of the optimal joint sourcechannelcoding scheme for transmission of correlated sources over multiple-access-relay channels (MARCs) is an open problem. Here, this problem is studied in the presenc...
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ISBN:
(纸本)9781479904464
The characterization of the optimal joint sourcechannelcoding scheme for transmission of correlated sources over multiple-access-relay channels (MARCs) is an open problem. Here, this problem is studied in the presence of arbitrarily correlated side information at both the relay and the destination. Since each transmitter observes only one of the sources, the admissible joint distributions of the sources and channel inputs must satisfy a Markov relationship which constrains their statistical dependence. This observation is used together with the new data processing inequality derived by [Kang and Ulukus, 2011] to obtain two new sets of single-letter necessary conditions. These new conditions are shown to be at least as tight as the previously known ones, and strictly tighter than the cut-set bound.
In this paper we propose an energy-aware scheme using joint source-channelcoding (JSCC) with unequal error protection (UEP) for scalable video delivery over packet-lossy networks. The proposed cross-layer approach jo...
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ISBN:
(纸本)9781479903085
In this paper we propose an energy-aware scheme using joint source-channelcoding (JSCC) with unequal error protection (UEP) for scalable video delivery over packet-lossy networks. The proposed cross-layer approach jointly consider the error protection at the physical layer, the energy consumption at the MAC layer, and the quality of service (QoS) at the application layer. Bits are optimally allocated based on the source compression and the channel correction coding, in accordance to both the wireless channel conditions and the energy constraints. For a certain intra refreshing rate of sourcecoding, the UEP scheme is capable of optimally allocating the channel redundancy among frames, with the lowest video distortion and energy consumption in wireless transmission. Simulations demonstrate that the proposed energy-aware JSCC scheme can significantly improve the video QoS, while the energy constraint is satisfied and the complexity associated with performing the cross-layer JSCC grouping algorithm is acceptable.
A new distributed joint source-channel code (DJSCC) is proposed for a communication network with spatial-temporally correlated Markov sources. The DJSCC is performed by puncturing the information bits of a systematic ...
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ISBN:
(纸本)9781467331227
A new distributed joint source-channel code (DJSCC) is proposed for a communication network with spatial-temporally correlated Markov sources. The DJSCC is performed by puncturing the information bits of a systematic linear block code but leaving the parity bits intact, and transmitting the information and parity bits with unequal energy allocations. At the receiver, the spatial data correlation is exploited with a new multi-codeword message passing (MCMP) decoding algorithm. The MCMP decoder performs decoding by exchanging information between codewords from correlated sources, whereas conventional message passing (MP) algorithms exchanges soft information only inside a codeword. The inter-codeword soft information exchange of MCMP yields additional performance gains over the MP algorithm. In recognition that the signals at the receiver arc distorted observations of the Markov source and thus can be modeled by a hidden Markov model (HMM), we propose to exploit the temporal data correlation by adding a HMM decoding module to the MCMP decoder. The HMM decoder iteratively exchanges soft information with the MCMP decoder, and this results in significant performance gains over conventional systems.
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