549 research outputs found
Exploiting 2-Dimensional Source Correlation in Channel Decoding with Parameter Estimation
Traditionally, it is assumed that source coding is perfect and therefore, the redundancy of the source encoded bit-stream is zero. However, in reality, this is not the case as the existing source encoders are imperfect and yield residual redundancy at the output. The residual redundancy can be exploited by using Joint Source Channel Coding (JSCC) with Markov chain as the source. In several studies, the statistical knowledge of the sources has been assumed to be perfectly available at the receiver. Although the result was better in terms of the BER performance, practically, the source correlation knowledge were not always available at the receiver and thus, this could affect the reliability of the outcome. The source correlation on all rows and columns of the 2D sources were well exploited by using a modified Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm in the decoder. A parameter estimation technique was used jointly with the decoder to estimate the source correlation knowledge. Hence, this research aims to investigate the parameter estimation for 2D JSCC system which reflects a practical scenario where the source correlation knowledge are not always available. We compare the performance of the proposed joint decoding and estimation technique with the ideal 2D JSCC system with perfect knowledge of the source correlation knowledge. Simulation results reveal that our proposed coding scheme performs very close to the ideal 2D JSCC system
Combining the Burrows-Wheeler Transform and RCM-LDGM Codes for the Transmission of Sources with Memory at High Spectral Efficiencies
In this paper, we look at the problem of implementing high-throughput Joint SourceChannel (JSC) coding schemes for the transmission of binary sources with memory over AWGN channels. The sources are modeled either by a Markov chain (MC) or a hidden Markov model (HMM). We propose a coding scheme based on the Burrows-Wheeler Transform (BWT) and the parallel concatenation of Rate-Compatible Modulation and Low-Density Generator Matrix (RCM-LDGM) codes. The proposed scheme uses the BWT to convert the original source with memory into a set of independent non-uniform Discrete Memoryless (DMS) binary sources, which are then separately encoded, with optimal rates, using RCM-LDGM codes
Joint Source Channel Decoding Exploiting 2D Source Correlation with Parameter Estimation for Image Transmission over Rayleigh Fading Channels
ThisĂÂ paperĂÂ investigatesĂÂ theĂÂ performanceĂÂ ofĂÂ aĂÂ 2- DimensionalĂÂ (2D)ĂÂ JointĂÂ SourceĂÂ ChannelĂÂ CodingĂÂ (JSCC)ĂÂ system assistedĂÂ withĂÂ parameterĂÂ estimationĂÂ forĂÂ 2DĂÂ imageĂÂ transmission overĂÂ anĂÂ AdditiveĂÂ WhiteĂÂ GaussianĂÂ NoiseĂÂ (AWGN)ĂÂ channelĂÂ and aĂÂ RayleighĂÂ fadingĂÂ channel.ĂÂ Baum-WelshĂÂ AlgorithmĂÂ (BWA) ĂÂ is employedĂÂ inĂÂ theĂÂ proposedĂÂ 2DĂÂ JSCCĂÂ systemĂÂ toĂÂ estimateĂÂ the source correlation statistics during channel decoding. The source correlation is then exploited during channel decoding using a Modified Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm. The performance of the 2D JSCC system with the BWA-based parameter estimation technique (2D-JSCC-PET1) is evaluated via image transmission simulations.ĂÂ TwoĂÂ images,ĂÂ eachĂÂ exhibitsĂÂ strongĂÂ and weakĂÂ sourceĂÂ correlationĂÂ areĂÂ consideredĂÂ inĂÂ theĂÂ evaluationĂÂ by measuring the Peak Signal Noise Ratio of the decoded images at theĂÂ receiver.ĂÂ The proposed 2D-JSCC-PET1 system is compared with various benchmark systems. Simulation results reveal that the 2D-JSCC-PET1 system outperforms the other benchmark systems (performance gain of 4.23 dB over the 2D-JSCC-PET2 system and 6.10 dB over the 2D JSCC system).ĂÂ The proposed system also can perform very close to the ideal 2D JSCC system relying on the assumption of perfect source correlation knowledge at the receiver that shown only 0.88 dB difference in performance gain
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