A symbol-wise decoder which employs a modified trellis diagram is suitable for decoding a convolutionally encoded bit sequence with M-ary frequency shift keying (FSK) modulation. Because performances of the symbol-wis...
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ISBN:
(纸本)9781665491532
A symbol-wise decoder which employs a modified trellis diagram is suitable for decoding a convolutionally encoded bit sequence with M-ary frequency shift keying (FSK) modulation. Because performances of the symbol-wise decoder degrade due to a branch with a large likelihood value, we have proposed an optimized puncturing pattern which minimizes the number of branches with large likelihood value in a shortest merged path. However, we need to search all candidate patterns to optimize the puncturing pattern for each parameter because the examined optimization is only for the specific parameter. Therefore, in order to improve efficiency of puncturing pattern optimization, we propose a simple design method of puncturing pattern for symbol-wise viterbi decoding. The proposed method extracts only puncturing patterns having few branches with large likelihood value by utilizing a table which indicates correspondence between an information bit and a coded bit in the shortest merged path. We show that the proposed method reduces the number of search patterns by about 75 % compared to the conventional full search method. Furthermore, the performance evaluation by computer simulation shows that the puncturing pattern designed by the proposed method achieves the performance improvement.
Polar codes are proven as the first codes to achieve the limit of channel capacity and have been adopted in 5G. Due to their construction characteristics and performance, they are expected to be utilized for flexible ...
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Polar codes are proven as the first codes to achieve the limit of channel capacity and have been adopted in 5G. Due to their construction characteristics and performance, they are expected to be utilized for flexible scenarios in 6G. For a given length of information, various code rates can be achieved by changing the number of frozen bits and by puncturing techniques. However, the arbitrary code rate is limited due to the core matrix, and the decoding performance is degraded resulting from the puncturing techniques. In order to improve the performance, this paper proposes a novel puncturing pattern selection scheme using an additional encoding process based on feedback values at the transmitter. The proposed scheme guarantees the punctured codeword bits to be definitely known by the receiver. As a consequence, the log-likelihood ratio (LLR) of the punctured codeword bits can be accordingly set to infinity at the decoder, resulting in the performance improvement. Simulation results demonstrate that the proposed puncturing scheme outperforms the existing schemes with a slightly increased complexity. (C) 2021 Elsevier B.V. All rights reserved.
puncturing is the most common way of increasing the rate of convolutional codes. The puncturing process is done to the original code called the mother code by a specific puncturing pattern. In this article, we investi...
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ISBN:
(纸本)9781467383080
puncturing is the most common way of increasing the rate of convolutional codes. The puncturing process is done to the original code called the mother code by a specific puncturing pattern. In this article, we investigate into the question whether any convolutional code is obtainable by puncturing some (n, 1) mother codes. We present two sufficient conditions for the mother code and the puncturing pattern to satisfy in order that the punctured code is equivalent to the given (N, K) convolutional code.
A method to design efficient puncture-constrained interleavers for turbo codes (TCs) is introduced. Resulting TCs profit from a joint optimization of puncturing pattern and interleaver to achieve an improved error rat...
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A method to design efficient puncture-constrained interleavers for turbo codes (TCs) is introduced. Resulting TCs profit from a joint optimization of puncturing pattern and interleaver to achieve an improved error rate performance. First, the puncturing pattern is selected based on the constituent code Hamming distance spectrum and on the TC extrinsic information exchange under uniform interleaving. Then, the interleaver function is defined via a layered design process taking account of several design criteria, such as minimum span, correlation girth, and puncturing constraints. We show that applying interleaving with a periodic cross connection pattern that can be assimilated to a protograph improves error-correction performance when compared to the state-of-the-art TCs. An application example is elaborated and compared with the longterm evolution standard: a significant gain in performance can be observed. An additional benefit of the proposed technique resides in the important reduction of the search space for the different interleaver parameters.
Low-density parity-check convolutional codes (LDPC-CCs) are generally decoded using sliding-window based message passing decoding. Based on the sliding-window decoding, an informed dynamic scheduling (IDS) for LDPC-CC...
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ISBN:
(纸本)9781509059324
Low-density parity-check convolutional codes (LDPC-CCs) are generally decoded using sliding-window based message passing decoding. Based on the sliding-window decoding, an informed dynamic scheduling (IDS) for LDPC-CC is proposed in this work, where the decoding convergence can be significantly accelerated. Since the number of processors required for a satisfactory performance can be reduced, the decoder can be simplified. A set of rate-compatible (RC) puncturing patterns is also proposed and is used to construct RC LDPC-CCs for the performance evaluation of the proposed IDS. Although the proposed puncturing pattern cannot be optimized for individual code rate owing to the rate-compatible constraint, they can still provide a comparable error rate performance compared to the codes defined in the IEEE 802.16m standard. It is worth noting that these standard codes are not rate-compatible.
Rate Compatible Punctured Convolutional (RCPC) code is a sub-class of convolutional code which allows varied levels of data protection to suit different types of data. RCPC is becoming extensively used in telecommunic...
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ISBN:
(纸本)9781479951918
Rate Compatible Punctured Convolutional (RCPC) code is a sub-class of convolutional code which allows varied levels of data protection to suit different types of data. RCPC is becoming extensively used in telecommunication systems as it offers bandwidth efficiency and simpler hardware implementation compared to convolutional coding, with comparable performance. RCPC codes are attained by puncturing several of the redundancy bits of convolutional codes. As accurate analysis of the bit error probability for a punctured convolutional encoder using state diagram and transfer function is not a straightforward process, in this paper we use non-punctured equivalent convolutional code to represent the punctured code. There are numerous puncturing patterns to yield RCPC codes from certain convolutional mother code. Our simulation results in AWGN and Rayleigh fading channels show that the same code rates yielded by different puncturing patterns will result in different code performance. Therefore, puncturing pattern is one of the key considerations in generating an RCPC code as it markedly affects the code performance.
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