Partially Information-Coupled Turbo Codes for LTE Systems

Yang, Lei; Xie, Yuan; Wu, Xiaowei; Yuan, Jinhong; Cheng, Xingqing; Wan, Lei

doi:10.1109/tcomm.2018.2841907

Cited by 42 publications

(41 citation statements)

References 27 publications

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“…It is also interesting to note that the decoding threshold of the PIC-TC with increased coupling memory remain unchanged. This behavior is similar to the SC-PCCCs in [12].…”

Section: A Density Evolution Resultssupporting

confidence: 76%

“…The decoding of PIC-TCs is accomplished by a feedforward and feed-back (FF-FB) decoding [12] in an iterative manner. In short, it employs a serial scheduling by decoding the first CB to the last CB serially and then starts from decoding the last CB to the first CB if necessary.…”

Section: B Decoding Of Pic-tcsmentioning

confidence: 99%

“…where (a) is based on the code rate given in [12,Eq. (9)] by considering coupling memory m and subtracting the number of bits for zero padding.…”

mentioning

confidence: 99%

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Density Evolution Analysis of Partially Information Coupled Turbo Codes on the Erasure Channel

Qiu

Xie

et al. 2019

2019 IEEE Information Theory Workshop (ITW)

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In this paper, we investigate the performance of a class of spatially coupled codes, namely partially information coupled turbo codes (PIC-TCs) over the binary erasure channel (BEC). This class of codes enjoy flexible code rate adjustment by varying the coupling ratio. Moreover, the coupling method can be directly applied to any component codes without changing the encoding and decoding architectures of the underlying component codes. However, the theoretical performance of PIC-TCs has not been fully investigated. For this work, we consider the codes that have coupling memory m and study the corresponding graph model. We then derive the exact density evolution equations for these code ensembles with any given coupling ratio and coupling memory m to precisely compute their belief propagation decoding thresholds for the BEC. Our simulation results verify the correctness of our theoretical analysis and also show better error performance over uncoupled turbo codes with a variety of code rates on the BEC.

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“…It is also interesting to note that the decoding threshold of the PIC-TC with increased coupling memory remain unchanged. This behavior is similar to the SC-PCCCs in [12].…”

Section: A Density Evolution Resultssupporting

confidence: 76%

Section: B Decoding Of Pic-tcsmentioning

confidence: 99%

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Density Evolution Analysis of Partially Information Coupled Turbo Codes on the Erasure Channel

Qiu

Xie

et al. 2019

2019 IEEE Information Theory Workshop (ITW)

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“…Turbo codes were proposed in 1993, and have been widely used in 3G and 4G wireless communication systems due to their good error correction [1]. Yang et al proposed new, partially information-coupled (PIC) turbo codes in 2018 [2], which can improve decoding performance without changing the decoder. The Log-MAP algorithm was often used in decoding turbo codes.…”

Section: Introductionmentioning

confidence: 99%

Turbo Decoder Design based on an LUT-Normalized Log-MAP Algorithm

Wang

et al. 2019

Entropy

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Turbo codes have been widely used in wireless communication systems due to their good error correction performance. Under time division long term evolution (TD-LTE) of the 3rd generation partnership project (3GPP) wireless communication standard, a Log maximum a posteriori (Log-MAP) decoding algorithm with high complexity is usually approximated as a lookup-table Log-MAP (LUT-Log-MAP) algorithm and Max-Log-MAP algorithm, but these two algorithms have high complexity and high bit error rate, respectively. In this paper, we propose a normalized Log-MAP (Nor-Log-MAP) decoding algorithm in which the function max* is approximated by using a fixed normalized factor multiplied by the max function. Combining a Nor-Log-MAP algorithm with a LUT-Log-MAP algorithm creates a new kind of LUT-Nor-Log-MAP algorithm. Compared with the LUT-Log-MAP algorithm, the decoding performance of the LUT-Nor-Log-MAP algorithm is close to that of the LUT-Log-MAP algorithm. Based on the decoding method of the Nor-Log-MAP algorithm, we also put forward a normalization functional unit (NFU) for a soft-input soft-output (SISO) decoder computing unit. The simulation results show that the LUT-Nor-Log-MAP algorithm can save about 2.1% of logic resources compared with the LUT-Log-MAP algorithm. Compared with the Max-Log-MAP algorithm, the LUT-Nor-Log-MAP algorithm shows a gain of 0.25~0.5 dB in decoding performance. Using the Cyclone IV platform, the designed Turbo decoder can achieve a throughput of 36 Mbit/s under a maximum clock frequency of 44 MHz.

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“…This Turbo codes are a class of high-performance forward error correction (FEC) codes which show extremely good BER performance near the Shannon's limit [1]. For codes with relatively large code length, the bit error rate or probability of error (Pe) approaches zero if the transmission rate is less than the channel capacity [2] mathematically given by [2].…”

Section: Introductionmentioning

confidence: 99%

Implementation of Turbo Codes for Noisy Channels in LTE Systems

Laad¹

2019

IJRASET

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Turbo codes can be viewed as a class of parallel concatenation of convolution codes which attain low Bit Error Rate in the waterfall region of the error even for relatively low Signal to Noise Ratio values. This paper presents an implementation of turbo codes. The approach used in this paper uses a recursive convolution encode due to good convergence of decoding at the receiving end. Block interleaving has been used to randomize or permute the bit stream. Puncturing has also been implemented to generate higher rate codes compared to the conventional r=1/3 encoder. This helps in generating higher rate turbo codes for noisy channels. Finally the decoding mechanism uses the soft input-soft output decoding. The performance of the system has been evaluated based on the bit error rate.

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Partially Information-Coupled Turbo Codes for LTE Systems

Cited by 42 publications

References 27 publications

Density Evolution Analysis of Partially Information Coupled Turbo Codes on the Erasure Channel

Density Evolution Analysis of Partially Information Coupled Turbo Codes on the Erasure Channel

Turbo Decoder Design based on an LUT-Normalized Log-MAP Algorithm

Implementation of Turbo Codes for Noisy Channels in LTE Systems

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