A Low Complexity Implementation in Hardware on Simplified Log-MAP Algorithm for T-TCM Decoding

2013 ◽  
Vol 433-435 ◽  
pp. 1539-1544
Author(s):  
Jian Wang ◽  
Jian Ping Li
Keyword(s):  
Computational Complexity ◽  
Low Complexity ◽  
Coded Modulation ◽  
Maclaurin Series ◽  
Logarithmic Term ◽  
Map Algorithm ◽  
Trellis Coded ◽  
Low Complexity Implementation ◽  
Simulation Results ◽  
Log Map

A simplified decoding algorithm for turbo trellis-coded modulation (T-TCM) is proposed, which is easy to implement in hardware. The algorithm exploits a new piece-wise function to replace the logarithmic term of the Jacobian logarithm based on the MacLaurin Series. Simulation results show that the proposed algorithm can archive log-MAP-similar decoding performance with a much lower computational complexity. It can reduce about 40% of calculation in contrast to the improved MAX-Log-MAP.

scholarly journals A Universal Low-Complexity Demapping Algorithm for Non-Uniform Constellations

2020 ◽  
Vol 10 (23) ◽  
pp. 8572
Author(s):  
Hao Wang ◽  
Mingqi Li ◽  
Chao Wang
Keyword(s):  
Euclidean Distance ◽  
Low Complexity ◽  
Coded Modulation ◽  
One Dimensional ◽  
Performance Loss ◽  
Point Analysis ◽  
Simulation Results ◽  
The One ◽  
Bit Interleaved Coded Modulation ◽  
Log Map

A non-uniform constellation (NUC) can effectively reduce the gap between bit-interleaved coded modulation (BICM) capacity and Shannon capacity, which has been utilized in recent wireless broadcasting systems. However, the soft demapping algorithm needs a lot of Euclidean distance (ED) calculations and comparisons, which brings great demapping complexity to NUC. A universal low-complexity NUC demapping algorithm is proposed in this paper, which creates subsets based on the quadrant of the two-dimensional NUC (2D-NUC) received symbol or the sign of the in-phase (I)/quadrature (Q) component of the one-dimensional NUC (1D-NUC) received symbol. ED calculations and comparisons are only carried out on the constellation points contained in subsets. To further reduce the number of constellation points contained in subsets, the proposed algorithm takes advantage of the condensation property of NUC and regards a constellation cluster containing several constellation points as a virtual point. Analysis and simulation results show that, compared with the Max-Log-MAP algorithm, the proposed algorithm can greatly reduce the demapping complexity of NUC with negligible performance loss.

Research on a Kind of Algorithm Cell Search in TD-LTE System

2013 ◽  
Vol 756-759 ◽  
pp. 4078-4081
Author(s):  
Fa Tang Chen ◽  
Chi Yun Xu
Keyword(s):  
Computational Complexity ◽  
Theoretical Analysis ◽  
Low Complexity ◽  
Theory Analysis ◽  
Cell Search ◽  
Low Complexity Implementation ◽  
Simulation Results ◽  
Implementation Method

According to the theoretical analysis of Zadoff-Chu sequence and theoretical derivation.A kind of low complexity implementation method of algorithm in cell search in TD-LTE system is proposed in this paper. Both the theory analysis and simulation results show that the algorithm proposed can reduce computational complexity and this algorithm is feasible and efficient, which gains good performance of cell search in TD-LTE system.

scholarly journals Simplified Log-MAP Algorithm for Very Low-Complexity Turbo Decoder Hardware Architectures

2014 ◽  
Vol 63 (3) ◽  
pp. 531-537 ◽  
Author(s):  
Maurizio Martina ◽  
Stylianos Papaharalabos ◽  
P. Takis Mathiopoulos ◽  
Guido Masera
Keyword(s):  
Low Complexity ◽  
Turbo Decoder ◽  
Map Algorithm ◽  
Hardware Architectures ◽  
Log Map

A Simplified CE Stopping Criterion for BICM-ID System

2013 ◽  
Vol 433-435 ◽  
pp. 1530-1534
Author(s):  
Miao Miao Li ◽  
Jian Ping Li
Keyword(s):  
Computational Complexity ◽  
Iterative Decoding ◽  
Rayleigh Fading ◽  
Coded Modulation ◽  
Cross Entropy ◽  
Stopping Criterion ◽  
Stopping Criteria ◽  
Adaptive Thresholds ◽  
Simulation Results ◽  
Bit Interleaved Coded Modulation

The iterative process of bit-interleaved coded modulation iterative decoding (BICM-ID) leads to the increase of computational complexity and decoding delay at the receiver, although it owns remarkable bit-error-rate (BER) performance both in additive Gaussian noise (AWGN) channel and Rayleigh fading channel. A variety of the stopping criteria are put forward to reduce the unnecessary iterations in the process. This paper presents a simplified cross-entropy (CE) stopping criterion based on CE criterion, which sets self-adaptive thresholds for different SNRs to decide whether to calculate the CE in the receiver. Simulation results show that the simplified CE criterion can obtain a better performance and lower computational complexity. The iterative number of the simplified CE criterion is about 12.2% less than the conventional CE criterion.

scholarly journals Convergence analysis of the unpunctured turbo trellis-coded modulation (UTTCM)

2019 ◽  
Vol 13 (2) ◽  
pp. 447
Author(s):  
Ahmed Haffane ◽  
Abdelhafid Hasni ◽  
Mustapha Khelifi ◽  
Boufeldja Kadri
Keyword(s):  
Gaussian Noise ◽  
Iterative Decoding ◽  
Information Transfer ◽  
Additive White Gaussian Noise ◽  
Coded Modulation ◽  
Extrinsic Information ◽  
Trellis Coded Modulation ◽  
Exit Chart ◽  
Trellis Coded ◽  
Simulation Results

In this paper, the performance of the Unpunctured Turbo Trellis-Coded Modulation (UTTCM) over Additive White Gaussian Noise (AWGN) channel is analyzed using the non-binary extrinsic information transfer (EXIT) chart. The exchange of the extrinsic information between the decoder components is tracked, allowing the generation of an EXIT chart, which is a powerful tool for analyzing the convergence behavior of iterative decoding and prediction of convergence position. The Simulation results are compared with the turbo cliff positions on the BER curves.

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