A novel decoding scheme, called syndrome-weight determination, was proposed by Chang et al. in 2008 for the Golay code, or the (23, 12, 7) quadratic residue code. This method is not only very simple in principle but a...
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A novel decoding scheme, called syndrome-weight determination, was proposed by Chang et al. in 2008 for the Golay code, or the (23, 12, 7) quadratic residue code. This method is not only very simple in principle but also suitable for parallel hardware design. Presented is a modified version for any binary quadratic residue codes which has been developed. Because of its regular property, the proposed decoder is suitable for both software design and hardware development.
In this paper, we present a simplification of log-BP algorithm which is able to reduce iterative times of decoding algorithm and save the hardware resource of decoder for LDPC codes. This simplification designs an imp...
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ISBN:
(纸本)9780769535708
In this paper, we present a simplification of log-BP algorithm which is able to reduce iterative times of decoding algorithm and save the hardware resource of decoder for LDPC codes. This simplification designs an improved layered-iterative decoding method without reducing the decoding performance, of which speed the updating of check nodes and variable nodes. Simulation results show that the improved layered-iterative log-BP algorithm with six-time iteration exhibits similar decoding performance to the traditional log-BP algorithm with ten-time iteration. When the improved log-BP and traditional log-BP both are simulated in ten-time iteration, the SNR of improved layer-iterative method decreases about 0.25 dB than that of traditional log-BP in the BER of 1e-2.
Noncoherent pulse-position modulation (PPM) with simple channel codes has the potential to realize ultra-low power (ULP) wireless design. In this paper, we develop a Wagner-like decoding rule for single-parity-check a...
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ISBN:
(纸本)9781467362337
Noncoherent pulse-position modulation (PPM) with simple channel codes has the potential to realize ultra-low power (ULP) wireless design. In this paper, we develop a Wagner-like decoding rule for single-parity-check and high-rate Reed-Solomon (RS) coded PPM schemes by simply 'flipping' the most unreliable received PPM symbol(s) to obtain a good balance between performance and coding complexity. The proposed algorithm can be considered as a list decoding algorithm that first generates a candidate codeword list based on the algebraic structure of the code before applying soft decisions to decode. This approach can result in more power-efficient realizations of the studied schemes. It is shown that our decoding approach can achieve near maximum likelihood decoding performance based on the trellis, while having a significantly lower decoding complexity. In addition, by exploiting the inherent advantage of PPM transmission, it is possible to reduce the candidate list to further simplify the decoding for RS-coded PPM without losing coding gain. This makes the proposed scheme more attractive for ULP communications.
We propose a decoding algorithm for the (u vertical bar u + v)-construction that decodes up to half of the minimum distance of the linear code. We extend this algorithm for a class of matrix-product codes in two diffe...
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We propose a decoding algorithm for the (u vertical bar u + v)-construction that decodes up to half of the minimum distance of the linear code. We extend this algorithm for a class of matrix-product codes in two different ways. In some cases, one can decode beyond the error-correction capability of the code.
In this paper the performance of LT codes is analyzed. And then, for the remaining part of information which can be decoded still exists when decoding failure, an improved message passing decoding algorithm which reta...
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In this paper the performance of LT codes is analyzed. And then, for the remaining part of information which can be decoded still exists when decoding failure, an improved message passing decoding algorithm which retains the original algorithm framework is proposed. The simulation results have shown that the improved message passing decoding algorithm improves the decoding rate and reduces decoding overhead on the premise of appropriately increasing decoding complexity.
Sparse integer least-squares problems come up in a wide range of applications including wireless communications and genomics. The sphere decoding algorithm can find near-optimal solution to these problems with reduced...
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ISBN:
(纸本)9781479903573
Sparse integer least-squares problems come up in a wide range of applications including wireless communications and genomics. The sphere decoding algorithm can find near-optimal solution to these problems with reduced average complexity if the knowledge of sparsity of the unknown vector is used in decoding. In this paper, we formulate a sphere decoding approach that relies on the l_0-norm constraint on the unknown vector to solve sparse integer least-squares problems. The expected complexity of this algorithm is derived analytically for sparse alphabets associated with common applications such as sparse channel estimation and validated via simulations. The results indicate superior performance and speed compared to the classical sphere decoding algorithm.
We examine the decoding of Matrix C in the 802.16e WiMAX standard. An exhaustive search and zero-forcing (ES-ZF) decoder and an exhaustive search and nulling canceling (ES-NC) decoder are proposed for uncoded systems....
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ISBN:
(纸本)9781467318808
We examine the decoding of Matrix C in the 802.16e WiMAX standard. An exhaustive search and zero-forcing (ES-ZF) decoder and an exhaustive search and nulling canceling (ES-NC) decoder are proposed for uncoded systems. The computational complexity of Matrix C decoding using the ES-ZF decoder is shown to be the same as the complexity of the ZF decoder for Matrix B decoding with twice the number of receive antennas times the complexity of the maximum likelihood (ML) decoder for Matrix B decoding with twice the number of receive antennas. Matrix C can be implemented in a 2×2 multiple-input multiple-output (MEMO) system using the ES-NC decoder with reduced complexity compared to ML decoding with no performance loss. For coded systems, double pruned trees using a zero-forcing (DPT-ZF) algorithm or nulling canceling (DPT-NC) algorithm are proposed. The DPT-NC decoder can be implemented in a 2×2 MIMO coded system with reduced complexity compared to the Max-Log decoding with no performance loss.
In a closed-loop brain-computer interface (BCI), adaptive decoders are used to learn parameters suited to decoding the user's neural response. Feedback to the user provides information which permits the neural tun...
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ISBN:
(纸本)9781632660244
In a closed-loop brain-computer interface (BCI), adaptive decoders are used to learn parameters suited to decoding the user's neural response. Feedback to the user provides information which permits the neural tuning to also adapt. We present an approach to model this process of co-adaptation between the encoding model of the neural signal and the decoding algorithm as a multi-agent formulation of the linear quadratic Gaussian (LQG) control problem. In simulation we characterize how decoding performance improves as the neural encoding and adaptive decoder optimize, qualitatively resembling experimentally demonstrated closed-loop improvement. We then propose a novel, modified decoder update rule which is aware of the fact that the encoder is also changing and show it can improve simulated co-adaptation dynamics. Our modeling approach offers promise for gaining insights into co-adaptation as well as improving user learning of BCI control in practical settings.
In this contribution, we propose a signal constellation for the the phase noise channel which does not require pilots thus increasing the effective information rate in a communication system. This constellation does n...
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ISBN:
(纸本)9781479913510
In this contribution, we propose a signal constellation for the the phase noise channel which does not require pilots thus increasing the effective information rate in a communication system. This constellation does not present rotational symmetry thus enabling decoding algorithms such as SPA, to converge without the use of pilots. We will provide Bit Error Rate (BER) simulations which show the superiority of this constellation over standard MPSK with pilots. Moreover, we will provide a method to analyze any arbitrary signal constellation and provide a figure of merit for its performance when iterative decoding algorithms are used.
It is widely recognized that emerging hardware technologies will be inherently unreliable. In this paper, we study the performance of finite-alphabet iterative decoders when implemented on noisy hardware built out of ...
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ISBN:
(纸本)9781479903573
It is widely recognized that emerging hardware technologies will be inherently unreliable. In this paper, we study the performance of finite-alphabet iterative decoders when implemented on noisy hardware built out of unreliable components. We derive a recursive expression for the error probability in terms of both the transmission noise and processing errors. We allow different components of the decoding algorithm associated with certain computational units (i.e., bit and check nodes of varying degrees in the underlying graph) to be implemented using a collection of processors with varying levels of processing error rates. Performance analysis and optimal resource allocation of a noisy Gallager E decoder is presented as an application example of our general derivation. Simulations demonstrate that the implementation of a noisy iterative decoder according to the proposed analysis-guided optimal resource allocation outperforms implementations based on uninformed resource allocation under the common resource budget.
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