125,159 research outputs found
Dataset for "Hardware-Efficient Node Processing Unit Architectures for Flexible LDPC Decoder Implementations"
No full textComparison of fixed-point CNPUs constructed using the proposed novel Dual-tree topology vs. three alternatives, for a range of input numbers I, measuring hardware resource requirements and maximum operating frequency.
The dataset is associated with the following publication:
P. Hailes, L. Xu, R. G. Maunder, B. M. Al-Hashimi, and L. Hanzo, “Hardware-Efficient Node Processing Unit Architectures for Flexible LDPC Decoder Implementations,” IEEE Trans. Circuits Syst. II Express Briefs, 2018.
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Irregular Variable Length Coding
No full textIn this thesis, we introduce Irregular Variable Length Coding (IrVLC) and investigate its applications, characteristics and performance in the context of digital multimedia broadcast telecommunications. During IrVLC encoding, the multimedia signal is represented using a sequence of concatenated binary codewords. These are selected from a codebook, comprising a number of codewords, which, in turn, comprise various numbers of bits. However, during IrVLC encoding, the multimedia signal is decomposed into particular fractions, each of which is represented using a different codebook. This is in contrast to regular Variable Length Coding (VLC), in which the entire multimedia signal is encoded using the same codebook. The application of IrVLCs to joint source and channel coding is investigated in the context of a video transmission scheme. Our novel video codec represents the video signal using tessellations of Variable-Dimension Vector Quantisation (VDVQ) tiles. These are selected from a codebook, comprising a number of tiles having various dimensions. The selected tessellation of VDVQ tiles is signalled using a corresponding sequence of concatenated codewords from a Variable Length Error Correction (VLEC) codebook. This VLEC codebook represents a specific joint source and channel coding case of VLCs, which facilitates both compression and error correction. However, during video encoding, only particular combinations of the VDVQ tiles will perfectly tessellate, owing to their various dimensions. As a result, only particular sub-sets of the VDVQ codebook and, hence, of the VLEC codebook may be employed to convey particular fractions of the video signal. Therefore, our novel video codec can be said to employ IrVLCs. The employment of IrVLCs to facilitate Unequal Error Protection (UEP) is also demonstrated. This may be applied when various fractions of the source signal have different error sensitivities, as is typical in audio, speech, image and video signals, for example. Here, different VLEC codebooks having appropriately selected error correction capabilities may be employed to encode the particular fractions of the source signal. This approach may be expected to yield a higher reconstruction quality than equal protection in cases where the various fractions of the source signal have different error sensitivities. Finally, this thesis investigates the application of IrVLCs to near-capacity operation using EXtrinsic Information Transfer (EXIT) chart analysis. Here, a number of component VLEC codebooks having different inverted EXIT functions are employed to encode particular fractions of the source symbol frame. We show that the composite inverted IrVLC EXIT function may be obtained as a weighted average of the inverted component VLC EXIT functions. Additionally, EXIT chart matching is employed to shape the inverted IrVLC EXIT function to match the EXIT function of a serially concatenated inner channel code, creating a narrow but still open EXIT chart tunnel. In this way, iterative decoding convergence to an infinitesimally low probability of error is facilitated at near-capacity channel SNRs
Iterative decoding convergence and termination of serially concatenated codes
No full textIn this paper we demonstrate that previously proposed serially concatenated codes only facilitate iterative decoding convergence towards points that are near but not at the top-right hand corner of the EXIT chart, which typically results in an error floor. Furthermore, we propose a novel method for approaching the (1,1) point of the EXIT chart, where the Maximum Likelihood (ML) Bit Error Ratio (BER) performance is attained. Our method employs specifically designed termination sequences having a free distance of at least two to terminate an inner recursive code. Additionally, we provide optimal termination sequences for a range of inner code designs. Finally, we demonstrate that our novel approach facilitates useful BER reductions in the challenging application scenario when employing short frame lengths of the order of 100 bits, which are typical in wireless sensor networks, for example
Concatenated Irregular Variable Length Coding and Irregular Unity Rate Coding
No full textIn this contribution we propose the novel serial concatenation of Irregular Variable Length Coding (IrVLC) and Irregular Unity Rate Coding (IrURC), where we matched the corresponding EXtrinsic Information Transfer (EXIT) functions to each other. This approach facilitates a higher degree of design freedom than matching the EXIT function of an irregular codec to that of a regular codec. As a result, a narrower EXIT chart tunnel can be created, facilitating operation at SNR values that are closer to the channel's capacity bound. The computational complexity and Bit Error Ratio (BER) performance of our IrVLC-IrURC scheme is favourable in comparison to the bench markers that replace either one or both of the irregular codecs by the equivalent-rate regular codec
Research data for "A Flexible FPGA-Based Quasi-Cyclic LDPC Decoder"
No full textDataset supporting:
Hailes, P., Xu, L., Maunder, R., Al-Hashimi, B., and Hanzo, L. (2017). A flexible FPGA-based quasi-cyclic LDPC decoder. IEEE Access. DOI: 10.1109/ACCESS.2017.2678103</span
Near-capacity irregular variable length coding and irregular unity rate coding
No full textIn this contribution we introduce an EXtrinsic Information Transfer (EXIT) chart matching technique for the design of two serially concatenated irregular codecs, each constituted by a variety of component codes. This approach facilitates a higher degree of design freedom than matching the EXIT function of an irregular codec to that of a regular codec, comprising only a single component code. As a result, a narrow EXIT chart tunnel can be created, facilitating operation at SNR values that are closer to the channel's capacity bound. This is demonstrated for a serial concatenation of iteratively decoded Irregular Variable Length Coding (IrVLC) and Irregular Unity Rate Coding (IrURC), which is favourably compared with an IrVLC and regular Unity Rate Coding (URC) based benchmarker. Finally, we show that the iterative decoding complexity of our IrVLC-IrURC scheme can be reduced by about 25% upon employing a method of jointly performing EXIT chart matching, while seeking a reduced iterative decoding complexit
Extrinsic Information Transfer Analysis and Design of Block-Based Intermediate Codes
No full textIntermediate codes have been shown to facilitate iterative decoding convergence to the maximum likelihood error ratio performance in serially concatenated schemes. In this paper, we propose a novel block-based intermediate code as an alternative to classic convolutional intermediate codes. Since it is block-based, our intermediate code facilitates practical implementations having reduced memory and processing requirements. Furthermore, we demonstrate that it is simpler to analyse and optimise the iterative decoding process, when our block-based intermediate code is employed instead of a convolutional intermediate code. Finally, we demonstrate that the proposed block-based intermediate code facilitates significantly reduced error ratios in practical schemes, when employing short transmission frames and a limited decoding complexity
Dataset for CRC-aided Logarithmic Stack Decoding of Polar Codes for Ultra Reliable Low Latency Communication in 3GPP New Radio
No full textThis dataset supports the publication:
Luping Xiang, ZEYNEP B. KAYKAC EGILMEZ, Robert G. Maunder and Lajos Hanzo;
CRC-aided Logarithmic Stack Decoding of Polar Codes for Ultra Reliable Low Latency Communication in 3GPP New Radio.
IEEE ACCESS
This dataset contains which are used for generating Fig.7 Fig.8 Fig.9 Fig.10 Fig.11 Fig.13 and Fig.14. These figures are plotted using GLE (Graphics Layout Engine). The scripts of Gle are also included in the folds for each figures. see readme file for more information.</span
On the complexity of unary error correction codes for the near-capacity transmission of symbol values from an infinite set
No full textUnary Error Correction (UEC) codes have recently been proposed for the near-capacity Joint Source and Channel Coding (JSCC) of symbol values that are selected from a set having an infinite cardinality. In this paper, we characterize the computational complexity of UEC decoders and use complexity analysis for striking a desirable trade-off between the contradictory requirements of low complexity and near-capacity operation. We investigate a wide range of application scenarios and offer a deep insight into their beneficial parameterizations. In particular, we introduce puncturing for controlling the scheme’s throughput and for facilitating fair comparisons with a Separate Source and Channel Coding (SSCC) benchmarker. The UEC scheme is found to offer almost 1.3 dB gain, when operating within 1.6 dB of the capacity bound. This is achieved without any increase in transmission energy, bandwidth, transmit duration or decoding complexity
Wireless MIMO Systems Employing Joint Turbo-Like STBC Codes With Bit-Level Algebraically-Interleaved URSCs
No full textIn this paper, permutations constructed based on algebraic derivations which are of particular interests due to better error-rate performance as well as simpler and practical hardware implementations, have been used in designing high performance fully-systematic joint space-time turbo coding technology. This scheme enjoys the integration of twin-/triplet-antenna bit-level space-time (ST) codes with the binary turbo-like codes of unpunctured codecs. The conducted performance evaluations reveal that this scheme has superior flare performance and yields additional coding gains in waterfall region, compared with the row-column block interleaved systems
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