Mohsen Moradi, Amir Mozammel · arXiv (Cornell University) · 2022
Sorting operation is one of the main bottlenecks for the successive-cancellation list (SCL) decoding. This paper introduces an improvement to the SCL decoding for polar and pre-transformed polar codes that reduces the number of sorting operations without degrading the code's error-correction performance. In an SCL decoding with an optimum metric function we show that, on average, the correct branch's bit-metric value must be equal to the bit-channel capacity, and on the other hand, the average bit-metric value of a wrong branch can be at most zero. This implies that a wrong path's partial path metric value deviates from the bit-channel capacity's partial summation. For relatively reliable bit-channels, the bit metric for a wrong branch becomes very large negative number, which enables us to detect and prune such paths. We prove that, for a threshold lower than the bit-channel cutoff rate, the probability of pruning the correct path decreases exponentially by the given threshold. Based on these findings, we presented a pruning technique, and the experimental results demonstrate a substantial decrease in the amount of sorting procedures required for SCL decoding. In the stack algorithm, a similar technique is used to significantly reduce the average number of paths in the stack.
Cited by 0Open access
Tian Peng Ren, Yong Liang Guan, Chau Yuen et al. · IEEE Journal of Selected Topics in Signal Processing · 2011
Full-rate space time codes (STCs) with rate number of transmit antennas have high multiplexing gain, but high decoding complexity even when decoded using reduced-complexity decoders such as sphere or QRDM decoders. In this paper, we introduce a new code property of STC called block-orthogonal property, which can be exploited by QR-decomposition-based decoders to achieve significant decoding complexity reduction without performance loss. We show that such complexity reduction principle can benefit the existing algebraic codes such as Perfect and DjABBA codes due to their inherent (but previously undiscovered) block-orthogonal property. In addition, we construct and optimize new full-rate block-orthogonal STC (BOSTC) that further maximize the QRDM complexity reduction potential. Simulation results of bit error rate (BER) performance against decoding complexity show that the new BOSTC outperforms all previously known codes as long as the QRDM decoder operates in reduced-complexity mode, and the code exhibits a desirable complexity saturation property.
Cited by 34Open access
Shu‐Ming Tseng, Mark R. Bell, Hsin-lung Lee · 2004
In this work, we will consider the problem of joint symbol synchronization and decoding of pulse position modulation (PPM) sequences in the deep-space photon-limited optical channel, where joint synchronization and decoding is significantly superior to separate synchronization and decoding. We also consider the design of codes having both good error control and synchronization properties for use with PPM signaling on this channel. While schemes for joint synchronization and decoding on this channel have been previously investigated, the complexity of these schemes has been prohibitive. In addition, their optimality with respect to computational complexity depends on the assumption that symbols are statistically independent and hence uncoded. We propose a two-stage joint synchronizer and decoder that achieve a selected performance requirement while reducing the complexity of joint synchronizer and decoder. The complexity is reduced by terminating synchronization once this error probability requirement is achieved, at which point the synchronizer/decoder functions only as a decoder on the remaining symbols in the received sequences. Therefore, the proposed scheme has practical complexity in the deep-space photon-limited optical channel, which may be used in the future deep-space missions.
Cited by 0
Sa’d, Adnan Haider Yusef · Universiti Sains Malaysia Institutional Repository (Universiti Sains Malaysia) · 2019
SLM is a well-known peak-to-average power ratio (PAPR) reduction technique that is capable of effectively reducing the system’s PAPR without distorting the signal. However, SLM causes a data rate loss issue due to the necessity for sending the selected iteration index to the receiver as side-information. To solve this issue, many blind SLM (BSLM) methods have been proposed in the literature. Such BSLM methods embed side-information in either pilot or data signals using phase or energy disparity forms. Hence, the receiver can blindly decode the signals using a maximum likelihood (ML) decoder. In this research, different data-based BSLM schemes with very low decoding complexity are proposed for both QAM and PSK modulation. The proposed BSLM schemes are broken down into three main stages for different system parameters (
Cited by 0Open access
Changlong Xu, Ying‐Chang Liang, Wing Seng Leon · 2007
Most, if not all, of the complexity reduction algorithms for turbo product code are concentrated only on the decoding part in previous literatures. In this paper, we propose very low complexity decoding algorithm for turbo product codes by considering both the encoding and decoding aspects. For the encoding part, a new encoding scheme is presented for turbo product codes to reduce the computing complexity. Performance improvement and further complexity reduction is achieved by modifying the existing decoding algorithm proposed by Pyndiah. Simulation results show that the proposed algorithm can improve the decoding performance while reducing the decoding complexity significantly
Cited by 3
Mohd Hairi Halmi, Muhammad Ahsan Shaikh, Khairunissa Ismail · 2015
This paper presents reduced signal decoding complexity 8×8 and 16×16 MIMO V-BLAST systems. The reduction in complexity is achieved by implementing a method that lowers the total the number of iterations needed in the decoding of the V-BLAST signals. Results show that the scheme is able to provide up to 71.06% signal decoding time reduction with minimal symbol-error-rate performance degradation. However, the percentage of complexity reduction lowers as number of antennas employed is increased.
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Ling, C., Mow, Wai Ho, Li, K.H. et al. · Research Portal (King's College London) · 2005
We present improved differential lattice decoding (DLD) for multi-antenna differential modulation by exploiting both basis reduction and sphere decoding. The extra complexity of DLD is shown to be worthwhile in terms of the obtained performance gain over Clarkson et al.'s decoding scheme. With roughly another fold of complexity of basis reduction, DLD augmented by a local search practically attains the maximum-likelihood decoding performance. © 2005 IEEE.
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Thanuja Mallikarachchi, Dumidu S. Talagala, Hemantha Kodikara Arachchi et al. · Future Internet · 2020
Video playback on mobile consumer electronic (CE) devices is plagued by fluctuations in the network bandwidth and by limitations in processing and energy availability at the individual devices. Seen as a potential solution, the state-of-the-art adaptive streaming mechanisms address the first aspect, yet the efficient control of the decoding-complexity and the energy use when decoding the video remain unaddressed. The quality of experience (QoE) of the end-users’ experiences, however, depends on the capability to adapt the bit streams to both these constraints (i.e., network bandwidth and device’s energy availability). As a solution, this paper proposes an encoding framework that is capable of generating video bit streams with arbitrary bit rates and decoding-complexity levels using a decoding-complexity–rate–distortion model. The proposed algorithm allocates rate and decoding-complexity levels across frames and coding tree units (CTUs) and adaptively derives the CTU-level coding parameters to achieve their imposed targets with minimal distortion. The experimental results reveal that the proposed algorithm can achieve the target bit rate and the decoding-complexity with 0.4% and 1.78% average errors, respectively, for multiple bit rate and decoding-complexity levels. The proposed algorithm also demonstrates a stable frame-wise rate and decoding-complexity control capability when achieving a decoding-complexity reduction of 10.11 (%/dB). The resultant decoding-complexity reduction translates into an overall energy-consumption reduction of up to 10.52 (%/dB) for a 1 dB peak signal-to-noise ratio (PSNR) quality loss compared to the HM 16.0 encoded bit streams.
Cited by 17Open access
Thanuja Mallikarachchi, Dumidu Talagala, Hemantha Kodikara Arachchi et al. · RePEc: Research Papers in Economics
Video playback on mobile consumer electronic (CE) devices is plagued by fluctuations in the network bandwidth and by limitations in processing and energy availability at the individual devices. Seen as a potential solution, the state-of-the-art adaptive streaming mechanisms address the first aspect, yet the efficient control of the decoding-complexity and the energy use when decoding the video remain unaddressed. The quality of experience (QoE) of the end-users’ experiences, however, depends on the capability to adapt the bit streams to both these constraints (i.e., network bandwidth and device’s energy availability). As a solution, this paper proposes an encoding framework that is capable of generating video bit streams with arbitrary bit rates and decoding-complexity levels using a decoding-complexity–rate–distortion model. The proposed algorithm allocates rate and decoding-complexity levels across frames and coding tree units (CTUs) and adaptively derives the CTU-level coding parameters to achieve their imposed targets with minimal distortion. The experimental results reveal that the proposed algorithm can achieve the target bit rate and the decoding-complexity with 0.4% and 1.78% average errors, respectively, for multiple bit rate and decoding-complexity levels. The proposed algorithm also demonstrates a stable frame-wise rate and decoding-complexity control capability when achieving a decoding-complexity reduction of 10.11 (%/dB). The resultant decoding-complexity reduction translates into an overall energy-consumption reduction of up to 10.52 (%/dB) for a 1 dB peak signal-to-noise ratio (PSNR) quality loss compared to the HM 16.0 encoded bit streams.
Cited by 0
Wenhao Liu, Zhengyi Jiang, Zhongyi Huang et al. · arXiv (Cornell University) · 2024
Reed-Solomon (RS) codes are constructed over a finite field that have been widely employed in storage and communication systems. Many fast encoding/decoding algorithms such as fast Fourier transform (FFT) and modular approach are designed for RS codes to reduce the encoding/decoding complexity defined as the number of XORs involved in the encoding/decoding procedure. In this paper, we present the construction of RS codes over the cyclic polynomial ring $ \mathbb{F}_2[x]/(1+x+\ldots+x^{p-1})$ and show that our codes are maximum distance separable (MDS) codes. Moreover, we propose the FFT and modular approach over the ring that can be employed in our codes for encoding/decoding complexity reduction. We show that our codes have 17.9\% encoding complexity reduction and 7.5\% decoding complexity reduction compared with RS codes over finite field, for $(n,k)=(2048,1984)$.
Cited by 0Open access
Satoshi Denno, Tsubasa Inoue, Takuya Fujiwara et al. · 2019
This paper proposes an iterative low complexity soft input decoding with assistance of the lattice reduction for overloaded MIMO. The proposed soft input decoding applies two types of lattice reduction-aided linear filters to estimate log-likelihood ratio (LLR) in order to reduce the computational complexity. A lattice reduction-aided linear with whitening filter is introduced for the LLR estimation in the proposed decoding. The equivalent noise caused by the linear filter is mitigated with the decoder output streams and the LLR is re-estimated after the equivalent noise mitigation. Furthermore, LLR clipping is introduced in the proposed decoding to avoid the performance degradation due to the incorrect LLRs. The proposed decoding achieves about 2dB better BER performance than the soft decoding with the exhaustive search algorithm, so called the MLD, at the BER of 1.0E-4, even though the complexity of the proposed decoding is 1/10 as small as that of the soft decoding with the exhaustive search.
Cited by 1
Zunaira Babar, Soon Xin Ng, Lajos Hanzo · IEEE Communications Letters · 2013
The iterative decoder of Turbo Trellis Coded Modulation (TTCM) exchanges extrinsic information between the constituent TCM decoders, which imposes a high computational complexity at the receiver. Therefore we conceive the syndrome-based block decoding of TTCM, which is capable of reducing the decoding complexity by disabling the decoder, when syndrome becomes zero. Quantitatively, we demonstrate that a decoding complexity reduction of at least 17% is attained at high SNRs, with at least 20% and 45% reduction in the 5^{th} and 6^{th} iterations, respectively.
Cited by 8
Ren Yang, Mai Xu, Lai Jiang et al. · 2016
The latest High Efficiency Video Coding (HEVC) standard significantly improves coding efficiency over H.264/AVC, at the cost of heavy encoding and decoding complexity. For reducing HEVC decoding complexity to a target, we propose in this paper a Subjective-Quality-Optimized Complexity Control (SQOCC) approach, which optimizes subjective quality loss caused by the decoding complexity reduction. First, a saliency detection method in HEVC domain is developed as the preliminary of subjective quality metric. Based on detected saliency, we establish a formulation to minimize subjective quality loss at the constraint of specific decoding complexity reduction, via disabling the deblocking filters of some Largest Coding Units (LCUs). Next, we utilize least square fitting to model functions in our formulation. We then provide a solution to our formulation, achieving subjective-quality-optimized complexity control for HEVC decoding. Finally, the experimental results show the effectiveness of our SQOC-C approach in terms of both control accuracy and subjective quality.
Cited by 4
Satoshi Denno, Tsubasa Inoue, Kawaguchi Yuta et al. · IEICE Transactions on Communications · 2019
This paper proposes a low complexity soft input decoding in an iterative linear receiver for overloaded MIMO. The proposed soft input decoding applies two types of lattice reduction-aided linear filters to estimate log-likelihood ratio (LLR) in order to reduce the computational complexity. A lattice reduction-aided linear with whitening filter is introduced for the LLR estimation in the proposed decoding. The equivalent noise caused by the linear filter is mitigated with the decoder output stream and the LLR is re-estimated after the equivalent noise mitigation. Furthermore, LLR clipping is introduced in the proposed decoding to avoid the performance degradation due to the incorrect LLRs. The performance of the proposed decoding is evaluated by computer simulation. The proposed decoding achieves about 2dB better BER performance than soft decoding with the exhaustive search algorithm, so called the MLD, at the BER of 10-4, even though the complexity of the proposed decoding is 1/10 as small as that of soft decoding with the exhaustive search.
Cited by 10Open access
Ashraf Mahran, Mohammed Benaissa · IEEE Communications Letters · 2004
This work proposes a new adaptive approach to the soft decision decoding of the so-called combined Chase-GMD class of algorithms (CGA). A reliability threshold is used to match the decoding performance to the channel conditions. As a result, a significant reduction in decoding complexity can be achieved by reducing the number of required algebraic decodings. The proposed adaptive application can achieve the upper performance limit of the CGA with significant complexity reduction.
Cited by 7
Tadashi Minowa, Hiroyuki Imai · 2002
This paper presents a new reduction method of both the computational complexity and storage requirements in the nonpunctured turbo decoding. The idea of the proposed algorithm is based on the computational complexity reduction, which is attendant upon the process of add-compare-select in each stage of iterative decoding. Therefore, the proposed method is completely different from all the other reduction algorithms presented before now. We compare the nonpunctured turbo code using the proposed reduction method with the punctured turbo code in terms of performance-complexity tradeoff. Simulation results show that the proposed approach provides an alternative encoding/decoding scheme of the classical punctured turbo coding for the application to high-data-rate wireless communications system.
Cited by 8
Xinyuan Qiao, Hangxuan Cui, Jun Lin et al. · 2021 7th International Conference on Computer and Communications (ICCC) · 2021
Polar codes are the first error-correcting codes that achieve the Shannon limit under successive cancellation (SC) decoding when the code length is infinite. However, the error-correcting performance of SC decoding is mediocre for short and moderate code lengths. Dynamic successive cancellation flip (DSCF) decoding has been proposed that performs extra SC decoding trails with multi-bit flipping to improve the performance of short and moderate polar codes. The DSCF decoding suffers from high computational complexity and decoding latency since all information bits are tested when searching for the flipping candidates, which leads to intensive metric calculations. To reduce the search complexity of the DSCF, a method based on the critical set (CS) is proposed in this paper to narrow the search range and two types of special nodes, rate-0 nodes and repetition nodes, are incorporated for further complexity reduction. Simulation results show that the proposed method can achieve more than 70% reduction in calculations on metrics, and up to 22.79% reduction in calculations on nodes without performance loss compared to the original DSCF decoding.
Cited by 2
Atta Rahman, Sajjad Ahmed Ghouri, Hanan Adeel et al. · 2011
In this paper, a Modified Iterative Decoding Algorithm (MIDA) is investigated for decoding of Product codes. Product codes provide a good code rate as well as a good BER performance. Moreover, they have a brute power to correct burst errors, which are very harmful in digital transmission. It is because product codes are correct row-wise as well as column-wise. Conventional iterative decoding algorithm initially proposed by Al-Askary based upon Maximum Likelihood (ML) scheme, has a huge complexity which is unaffordable for long codes used in real time transmissions. MIDA being a sub-optimum algorithm reduces its complexity in an efficient way by utilizing the basic idea of Syndrome Decoding of Linear Block Codes. So decoding becomes more efficient also the complexity reduction factor increases with each iteration. The worst case complexity of MIDA is closed to that of conventional algorithm but in average case there is huge reduction in complexity, with negligible performance degradation.
Cited by 7
Atta Rahman · 2012
In this paper, performance of Modified Iterative Decoding Algorithm (MIDA) is investigated for decoding of Multi-level codes. MIDA is a hard decision decoder that was initially proposed for decoding of Product codes, by same authors. In this paper same concept is being extended for Multi-level codes. The basic iterative decoder has a huge complexity which is unaffordable for long constituent codes especially when used in real time systems. In MIDA, the idea of Syndrome Decoding is used for search space reduction. Moreover, it is found that complexity reduction factor increases with each iteration. The worst case complexity of MIDA is closed to that of basic algorithm but in average case there is huge reduction in complexity, with negligible performance degradation. Performance of the proposed algorithm is investigated over an OFDM system. Additive White Gaussian Noise (AWGN) channel and Rayleigh fading channel are used for simulations.
Cited by 2
Abdoul-Hadi Konfé, Pasteur Poda, Raphaël Le Bidan · 2024
We investigate in this paper how to optimize the number of iterations required for sliding window decoding of low-density parity-check (LDPC) codes. The aim of this study is to reduce decoding complexity and overcome the phenomenon of decoder blocking. We propose a new design of SC-LDPC codes based on some 5G short LDPC codes to reduce decoding complexity. Simulation results demonstrate a potential reduction in decoding computational complexity of the order of 30% without significant degradation in decoding performance. In addition to taking care of complexity, this mitigates the problem of sliding window decoder blocking by reducing the probability of observing this phenomenon.
Cited by 1