Improved log-MAP decoding algorithm for turbo-like codes

2006 ◽  
Vol 10 (3) ◽  
pp. 186-188 ◽  
Author(s):  
Hao Wang ◽  
Hongwen Yang ◽  
Dacheng Yang
Keyword(s):  
Decoding Algorithm ◽  
Map Decoding ◽  
Log Map

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

Entropy ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 814
Author(s):  
Jun Li ◽  
Xiumin Wang ◽  
Jinlong He ◽  
Chen Su ◽  
Liang Shan
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Lookup Table ◽  
Clock Frequency ◽  
High Complexity ◽  
Decoding Algorithm ◽  
Turbo Decoder ◽  
Map Algorithm ◽  
Map Decoding ◽  
Log Map

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.

Constant log-MAP decoding algorithm for duo-binary turbo codes

2006 ◽  
Vol 42 (12) ◽  
pp. 709 ◽  
Author(s):  
S. Papaharalabos ◽  
P. Sweeney ◽  
B.G. Evans
Keyword(s):  
Turbo Codes ◽  
Decoding Algorithm ◽  
Map Decoding ◽  
Log Map

Butterfly Log-MAP decoding algorithm

2004 ◽  
Vol 6 (3) ◽  
pp. 209-215
Author(s):  
Jia Hou ◽  
Moon Ho Lee ◽  
Chang Joo Kim
Keyword(s):  
Decoding Algorithm ◽  
Map Decoding ◽  
Log Map
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