Title :
Modified Log-MAP Algorithm for Simplified Decoding of Turbo and Turbo TCM Codes
Author :
Papaharalabos, Stylianos ; Sybis, Michal ; Tyczka, Piotr ; Mathiopoulos, P. Takis
Author_Institution :
Inst. for Space Applic. & Remote Sensing, Nat. Obs. of Athens, Athens
Abstract :
A novel method for approximating the optimal max* operator in Log-MAP decoding of turbo and turbo trellis-coded modulation (TTCM) codes is presented. The max* operation is performed on n>2 rather than on only two inputs, as it is in the conventional approach. The approximation uses a very simple max operation and a look-up table (LUT) with only eight stored values. Complexity comparison reveals a significant reduction in the number of operations required per decoding step for the presented approximation, as compared with the conventional Log-MAP decoding. Performance evaluation results are presented for both turbo and TTCM codes, showing the near-optimal performance of the novel approach.
Keywords :
table lookup; trellis coded modulation; turbo codes; log-MAP decoding; look-up table; modified log-map algorithm; turbo TCM codes; turbo codes; turbo trellis-coded modulation codes; Bit error rate; Concatenated codes; Convolutional codes; Degradation; Iterative decoding; Modulation coding; Remote sensing; Table lookup; Turbo codes; Wireless communication;
Conference_Titel :
Vehicular Technology Conference, 2009. VTC Spring 2009. IEEE 69th
Conference_Location :
Barcelona
Print_ISBN :
978-1-4244-2517-4
Electronic_ISBN :
1550-2252
DOI :
10.1109/VETECS.2009.5073689