Hardware implementation of Max-Log-MAP algorithm based on MacLaurin series for turbo decoder

2011 ◽  
Author(s):  
Rahul Shrestha ◽  
Roy Paily
Keyword(s):  
Hardware Implementation ◽  
Maclaurin Series ◽  
Turbo Decoder ◽  
Map Algorithm ◽  
Log Map

scholarly journals Efficient MAP-algorithm implementation on programmable architectures

2003 ◽  
Vol 1 ◽  
pp. 259-263 ◽  
Author(s):  
F. Kienle ◽  
H. Michel ◽  
F. Gilbert ◽  
N. Wehn
Keyword(s):  
Turbo Codes ◽  
Communication Systems ◽  
Building Blocks ◽  
Communication Performance ◽  
Channel Decoding ◽  
Turbo Decoder ◽  
Decoding Algorithms ◽  
Map Algorithm ◽  
Algorithm Implementation ◽  
Log Map

Abstract. Maximum-A-Posteriori (MAP) decoding algorithms are important HW/SW building blocks in advanced communication systems due to their ability to provide soft-output informations which can be efficiently exploited in iterative channel decoding schemes like Turbo-Codes. Multi-standards demand flexible implementations on programmable platforms. In this paper we analyze a quantized turbo-decoder based on a Max-Log-MAP algorithm with Extrinsic Scaling Factor (ESF). Its communication performance approximate to a Turbo-Decoder with a Log-MAP algorithm and is less sensitive to quantization effects. We present Turbo-Decoder implementations on state-of-the-art DSPs and show that only a Max-Log-MAP implementation fulfills a throughput requirement of ~2 Mbit/s. The negligible overhead for the ESF implementation strengthen the use of Max-Log-MAP with ESF implementation on programmable platforms.

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 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 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.

Sign in / Sign up

Export Citation Format

Share Document