Alpha channel is being applied in an increasing number of mobile web applications on mobile devices that require ultra-low power consumption in all cases including compute-intensive video encoding and decoding. Thus, ...
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Alpha channel is being applied in an increasing number of mobile web applications on mobile devices that require ultra-low power consumption in all cases including compute-intensive video encoding and decoding. Thus, we propose an ultra-low coding complexity and high efficiency alpha channel lossless coding approach. A novel coding framework and four new coding schemes are proposed for alpha channel coding. The framework fuses a string matching technique and a proposed prediction coding scheme named bit-depth preserving prediction (BDPP) together to reduce the correlations within and between repeated identical patterns and neighboring pixels. To achieve a good tradeoff between complexity and efficiency, either the unmatchable bytes are coded directly or the BDPP residuals of unmatchable bytes are coded by a proposed bytewise entropy coding scheme named 0.5-1-2byte-size-code. The other string matching parameters are coded by another proposed bytewise entropy coding scheme named byte-size multi-variable-length-code. To speed up the string-matching search, we apply a fast string search scheme that combines special position search and hash-based search. For the selected typical 236 alpha test images, compared with x265 in the fastest configuration and lossless mode, the proposed lossless approach achieves 14.33% less total compressed bytes with only 2.75% encoding and 1.83% decoding runtime. The proposed approach also outperforms the conventional lossless coding techniques such as LZ4HC, ZLIB, and PNG.
Error detection and error correction are one of the pillars of any communication system which serve as an error correction mechanism and improve signal quality. In this paper, we present a turbo channel coding algorit...
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ISBN:
(纸本)9781728107165
Error detection and error correction are one of the pillars of any communication system which serve as an error correction mechanism and improve signal quality. In this paper, we present a turbo channel coding algorithm for up-link transport channel in narrowband internet of things. The proposed channel coding uses 24-bit CRC syndrome calculator and turbo codes with a tail bit convolutional encoder to transmits NB-IoT packet date from MAC layer to physical layer over AWGN. In addition, we carried out performance analysis and simulation of the proposed algorithm in accordance with NB-IoT requirement specified by 3GPP standard.
Joint source-channel coding (JSCC) has achieved great success due to the introduction of deep learning (DL). Compared to traditional separate source-channel coding (SSCC) schemes, the advantages of DL-based JSCC (DJSC...
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Joint source-channel coding (JSCC) has achieved great success due to the introduction of deep learning (DL). Compared to traditional separate source-channel coding (SSCC) schemes, the advantages of DL-based JSCC (DJSCC) include high spectrum efficiency, high reconstruction quality, and relief of "cliff effect". However, it is difficult to couple existing secure communication mechanisms (e.g., encryption-decryption mechanism) with DJSCC in contrast with traditional SSCC schemes, which hinders the practical usage of this emerging technology. To this end, our paper proposes a novel method called DL-based joint protection and source-channel coding (DJPSCC) for images that can successfully protect the visual content of the plain image without significantly sacrificing image reconstruction performance. The idea of the design is to use a neural network to conduct visual protection, which converts the plain image to a visually protected one with the consideration of its interaction with DJSCC. During the training stage, the proposed DJPSCC method learns: 1) deep neural networks for image protection and image deprotection, and 2) an effective DJSCC network for image transmission in the protected domain. Compared to existing source protection methods applied with DJSCC transmission, the DJPSCC method achieves much better reconstruction performance.
In this paper, a communication system using vector quantization (VQ) and channel coding is considered. Here, a design scheme has been proposed to optimize source codebooks in the transmitter and the receiver. In the p...
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In this paper, a communication system using vector quantization (VQ) and channel coding is considered. Here, a design scheme has been proposed to optimize source codebooks in the transmitter and the receiver. In the proposed algorithm, the overall distortion including both the quantization error and channel distortion is minimized. The proposed algorithm is different from the previous work by the facts that the channel encoder is used in the VQ-based communication system, and the source VQ codebook used in the transmitter is different from the one used by the receiver, i.e. asymmetric VQ system. And the bounded-distance decoding (BDD) technique is used to combat the ambiguousness in the channel decoder. We can see from the computer simulations that the optimized system based on the proposed algorithm outperforms a conventional system based on a symmetric VQ codebook. Also, the proposed algorithm enables a reliable image communication over noisy channels.
A novel technique is described for distributed channel coding in wireless communication networks. The protocol is based on a block fading model of the multi-user uplink channel and on adapting multidimensional trellis...
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A novel technique is described for distributed channel coding in wireless communication networks. The protocol is based on a block fading model of the multi-user uplink channel and on adapting multidimensional trellis coded modulation techniques to a coding theorem derived for the block fading channel. The coded modulation (CM) protocol is designed to optimise code performance, especially at high spectral efficiencies. The CM protocol is very simple to implement at the cooperating users. Complexity is completely transferred to the destination. The latency of the protocol is only one symbol. The CM protocol achieves full diversity order equal to the number of cooperating users and maximises coding gains by designing the code for the specific modulation used. We derive analytical results and present simulation results showing the benefits of CM protocol over other comparable schemes.
The motion-compensated temporal filtering (MCTF)-based scalable video coding (SVC) provides a full scalability including spatial, temporal and signal-to-noise ratio (SNR) scalability with fine granularity, each of whi...
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The motion-compensated temporal filtering (MCTF)-based scalable video coding (SVC) provides a full scalability including spatial, temporal and signal-to-noise ratio (SNR) scalability with fine granularity, each of which may result in different visual effect. This paper addresses a novel approach of two-dimensional unequal error protection (2-D UEP) for the scalable video with a combined temporal and quality (SNR) scalability over packet-erasure channel. The bit-stream is divided into scalable subbitstreams based on the structure of MCTF. Each subbitstream is further divided into several quality layers. Unequal quantities of bits are allocated to protect different layers to obtain acceptable quality video with smooth degradation under different transmission error conditions. Experimental results are presented to show the advantage of the proposed 2-D UEP scheme over the traditional one-dimensional unequal error protection (1-D UEP) scheme. Comparing the proposed method with the 1-D UEP scheme on SNR layers, our method gives up to 0.81-dB improvement for some video sequences.
Low-capacity scenarios have become increasingly important in the technology of Internet of Things (IoT) and the next generation of mobile networks. Such scenarios require efficient and reliable transmission of informa...
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ISBN:
(纸本)9781538669006
Low-capacity scenarios have become increasingly important in the technology of Internet of Things (IoT) and the next generation of mobile networks. Such scenarios require efficient and reliable transmission of information over channels with an extremely small capacity. Within these constraints, the performance of state-of-the-art coding techniques is far from optimal in terms of either rate or complexity. Moreover, the current non-asymptotic laws of optimal channel coding provide inaccurate predictions for coding in the low-capacity regime. In this paper, we provide the first comprehensive study of channel coding in the low-capacity regime. We will investigate the fundamental non-asymptotic limits for channel coding as well as challenges that must be overcome for efficient code design in low-capacity scenarios.
Long distance molecular communication (MC) is prone to channel errors, leading to an increased bit error rate. For solving the issue, a new coding scheme named weak sequence preventive mapping code is designed, confor...
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ISBN:
(纸本)9781450398671
Long distance molecular communication (MC) is prone to channel errors, leading to an increased bit error rate. For solving the issue, a new coding scheme named weak sequence preventive mapping code is designed, conforming to the channel characteristics of the macroscopic air-based MC using fluorescent dye. The scheme not only minimizes the transmission errors, but also conserves the resource in the form of sprayed water-based dye solution.
A two-branch phase sweeping transmitter diversity scheme that can produce forced fast fading at the receiver is proposed for improving the effect of channel coding on bit error rate (BER) performance in very slow mult...
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A two-branch phase sweeping transmitter diversity scheme that can produce forced fast fading at the receiver is proposed for improving the effect of channel coding on bit error rate (BER) performance in very slow multipath fading environments. While the proposed transmitter diversity requires two transmit antennas, a single receive antenna can be used. Hence, it is most applicable for digital paging systems that require very simple receivers. The digital modulated signal is transmitted simultaneously from the two spatially separated antennas, with the carrier for one antenna being phase modulated by the phase sweeping function eta(t). Two sweeping functions are considered: eta(t) = DELTA-THETA sin(2-pi-f(H)t) (sinusoidal) and 2-pi-f(H)t (linear). An analysis shows that when bit interleaving of m-bit depth is used, it is required that DELTA-THETA > pi and mnf(H)T > 1/2 (sinusoidal) or >1 (linear) where n is the codeword length of the error correction code and T is the bit length of the digital transmission. When 32-kbps transmission with m = 10-bits interleaving and BCH (23,12) error correction code (n = 23) are used, f(H) = 70 Hz is sufficient for the sinusoidal phase sweeping function. Therefore, bandwidth expansion due to phase sweeping is negligible. Experimental results on transmitter diversity with the sinusoidal phase sweeping function are presented for 32 kbps quarternary differential phase shift keying (QDPSK) with differential detection.
It is known that perfect noiseless feedback can be used to improve the reliability of communication systems. We show how to make those gains robust to noise on the feedback link. We focus on feedback links that are th...
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It is known that perfect noiseless feedback can be used to improve the reliability of communication systems. We show how to make those gains robust to noise on the feedback link. We focus on feedback links that are themselves discrete memoryless channels. We demonstrate that Forney's erasure-decoding exponent is achievable given any positive-capacity feedback channel. We also demonstrate that as the desired rate of communication approaches the capacity of the forward channel, the Burnashev upper bound on the reliability function is achievable given any positive-capacity noisy feedback channel. Finally, we demonstrate that our scheme dominates the erasure-decoding exponent at all rates and, for instance, at zero rate can achieve up to three-quarters of Burnashev's zero-rate reliability. This implies that in a shared medium, to maximise the reliability function some degrees of freedom should be allocated to feedback. Copyright (C) 2008 John Wiley & Sons, Ltd.
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