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This paper presents a non-binary finite-stat Markov channel (FSMC) that captures both the soft-decision information and the temporal correlation of a discrete fading channel (DFC) with 2ξ quantization levels. The parameters of the FSMC that approximate the DFC with fixe parameters are found using the Baum-Welch algorithm. An iterative decoding scheme, based on the sum-product algorithm, is also discussed...
Low-density parity-check (LDPC) coded massive multiple-input and multiple-output (MIMO) scheme is getting increasingly popular and sophisticated in today's wireless communication systems, since it can highly improve the spectral efficiency, data rates, and error performance. In this paper, a novel iterative detection and decoding (IDD) method for LDPC-coded massive MIMO systems is proposed. Based...
For practical applications in forward error correction, the importance of a systematic codeword cannot be overemphasized. Thus, this paper proposes the construction of a systematic quasi-cyclic (QC) LDPC code. This systematic structure is achieved by a row reduction technique different from the conventional Gaussian elimination method. This row reduction technique has the advantage of being easier...
LDPC codes have been applied in recent communication standards, such as WiFi, WiGig, and 10GBased-T Ethernet as a forward error correction code. However, LDPC codes require a large number of computational complexity for high performances. To solve this problem, various studies have been continuously performed for reducing computational complexity. In this paper, we propose an adaptive forced convergence...
Spatially coupled low-density parity-check (SC-LDPC) codes are often thought as codes with very long block lengths. However, they can be decoded through sliding window (SW) decoders achieving near-optimal performance when the window size is a few times larger than the code syndrome former constraint length. This makes SC-LDPC codes with short constraint length suitable for low-latency transmissions,...
Recently, both polar codes and low-density parity-check (LDPC) codes have been adopted by 3GPP eMBB scenario. Since both codes exist in one system, it is natural to consider the concatenation scheme of them. In this paper, a merged belief propagation (BP) decoding algorithm for the concatenated codes of polar and LDPC codes is proposed. By jointing factor graphs, this merged algorithm is designed...
This paper presents a fully pipelined layered decoder architecture for IEEE 802.11 n/ac/ax LDPC codes, free of idle cycles. Several decoder architectures for such codes have emerged in the literature featuring throughputs in the multi- Gbps range. The proposed architecture surpasses the highest reported throughput for IEEE 802.11 n/ac/ax LDPC codes. This is achieved 1) algorithmically, by implementing...
Spatially coupled (SC) low-density parity-check (LDPC) codes can achieve capacity approaching performance with low message recovery latency when using sliding window (SW) decoding. An SC-LDPC code constructed from a protograph can be generated by first coupling a chain of block protographs and then lifting the coupled protograph using permutation matrices. This paper introduces a systematic design...
In order to relieve reliability problem caused by technology scaling, LDPC codes have been widely applied in flash memories to provide high error correction capability. However, LDPC read performance slowdown along with data retention largely weakens the access speed advantage of flash memories. This paper considers to apply the concept of refresh, that were used for flash lifetime improvement, to...
One of the most important solutions for spectrum shortage, expected by 2020, is wireless networks with super density, which is also expected to provide significant economic impacts. This paper proposes decoding scheme with practical analysis for massive number of users in super-dense wireless networks involving two multiway relays (SD-MWMR). The practicality is viewed from the point of finite-length...
In some practical applications, impulsive noise can severely degrade the performance of a communication system. As a class of powerful error correction codes, Low-density parity-check (LDPC) codes have been shown superior performance on AWGN channels. In addition, belief propagation (BP) decoding algorithm of LDPC codes based on scheduling strategy has better performance and faster convergence rate...
This paper proposes an efficient rateless low-density parity check (LDPC) codes for satellite broadcasting system. The proposed scheme uses the conventional LDPC codes specified in recent digital video broadcasting via satellite (DVB-S) standards, and concatenate them with Luby transform (LT)-like codes in order to form systematic rateless codes. In this way, redundant parities can be made at the...
Gradient descent bit-flipping (GDBF) decoding for low-density parity-check (LDPC) codes has gained great attentions because of low complexity and relatively good performance. However, the performance of the GDBF decoding is still much poorer than that of the MS algorithm. To further improve the performance, the iterative decoding process is introduced to GDBF decoding in this paper. At the end of...
LDPC code is a powerful error correcting code used in many communication systems. Efficient decoding algorithm and hardware implementation of LDPC code is an important issue. The paper proposes an improved version of the Normalized Min-Sum (NMS) decoding algorithm named “Girth-Aware NMS”. The principle of the GA-NMS is to determine “offline” the optimal normalisation factor of the extrinsic message...
This paper introduces a novel post-processing algorithm for low-density parity-check (LDPC) codes adequate for NAND flash memory, to improve error correction capability of a soft decision decoding by reducing strong error effects in an efficient way. In this algorithm, it can detect variable nodes of strong errors using incoming check-to-variable (c2v) messages and reduce magnitude of channel reliability...
A previous study shows that a low-density parity-check (LDPC) coded modulation scheme with an extremely sparse parity-check matrix and non-Gray mapping is able to achieve an error-rate performance compatible to that of a conventional Gray-mapping based scheme. This paper presents an associated iterative demodulation and decoding (IDD) receiver architecture that is targeted at flash memory applications...
This paper presents a linear model for the sum-product decoding of random low-density parity-check (LDPC) codes, specifically in the high signal-to-noise ratio (SNR) region. The sum-product algorithm is first approximated as the min-sum algorithm and then a linear model is estimated for the latter. To formulate the model, the dominant trapping sets of the particular code are found. We consider a criterion...
The throughput of a conventional rate-compatible code based hybrid automatic repeat request (HARQ) protocol is lower-bounded by the rate of the mother code used. The mother code rate along with the highest puncture rate determine the operation range of the protocol in terms of the average received signal-to-noise ratio (SNR). In this paper, we propose a new HARQ protocol based on rate-compatible punctured...
This paper introduces a linear permutation module before the inner encoder of the iteratively decoded product coding structure, for the transmission of scalable bit streams over error-prone channels1. This can improve the error correction ability of the inner code when some source bits are known from the preceding outer code decoding stages. The product code consists of a protograph low-density parity-check...
To increase throughput efficiency and improve performance, FTN (Faster Than Nyquist) method and LDPC (Low Density Parity Codes) codes are employed in DVB-S3 system. In this paper, we proposed efficient turbo equalization model to minimize inter symbol interference induced by FTN transmission. To make performance improved in turbo equalization model, the outputs of LDPC and BCJR (Bahl, Cocke, Jelinek...
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