Performance of Turbo Product Code Decoding in 802.16 Systems Amruta P. Pokhare Assistant Professor Atharva College of Engineering, Mumbai, India. Sachin Gavhane Assistant Professor Atharva College of Engineering, Mumbai, India. Trushita Chaware Assistant Professor MIT Engg. College, Mumbai, India. Nileema Pathak Assistant Professor Atharva College of Engineering, Mumbai, India. Mohan Pawar Assistant Professor VES Institute of Technology, Mumbai, India. Abstract-- In this paper, the effect of TPC decoding using Chase-II algorithm with reduced number of test patterns (TPs) was evaluated using the AWGN channel in orthogonal frequency division multiplexing (OFDM) mode is discussed. TPC is constructed with multi-error-correcting extended Bose-Chaudhuri-Hocquengem (eBCH) codes. TPs are classified into different conditions based on the relationship between syndromes and the number of errors so that TPs with the same codeword are not decoded except the one with the least number of errors. The parameters considered are bit error rate (BER), Eb/N0, data rate and code rate. There are total six simulated results drawn. Out off which three results represents BER versus signal to noise ratio (SNR) for eBCH(128, 113, 2) when p= 2, 3 in 802.16 system respectively. The simulated results show BER of 6.57 X 10-5 at SNR 1dB, BER of 3.9186 X 10-4 at SNR 1dB and 8.7557 X 10-5 at 1.5dB and BER of 8.1112 X 10-4 at SNR 1dB and 1.0572 X 10-5 at 2dB for eBCH(128,113,2) where p= 2, 3 respectively. The other three results represent the percent of TPs decoded in 802.16 systems respectively. The research contribution shows that the percent of TPs need to be decoded for eBCH (128, 113, 2) when p = 2, 3 for 1st iteration it is between 22% - 10% and for 5th iteration onwards it is between 14% - 6% for SNR = 1.5dB, 1.8dB, 2.0dB, 2.2dB, 2.4dB and 2.5dB in 802.16 system, respectively. This research contribution helps to make the 802.16 systems simpler, reduces the decoding time, complexity and improves the performance. Keywords--Turbo product codes, Chase II algorithm, test patterns, extended BCH codes, 802.16 system. I. INTRODUCTION 802.16 is commonly called as Worldwide Interoperability for Microwave access (Wi-MAX). It provides specifications for both fixed Line of sight (LOS) communication in the range of 10-66GHz (802.16c) and fixed portable Non-LOS communication in the range of 2- 11GHz (802.16a, 802.16d). Also it defines wireless communication for mobiles, moving at speed of 125 kmph, in the range of 2-6 GHz (802.16e). Earlier single carrier multiplexing was used, which faced a major limiting factor of Inter symbol interference (ISI). 802.16e is well implemented with Orthogonal Frequency Division Multiplexing (OFDM) as its physical layer scheme as an alternative for the Single carrier multiplexing [1]. Hence, it was decided to implement 802.16e OFDM systems. Efficient communication systems permit a high rate of information to be communicated with the lowest possible power. Commonly used error correcting codes for a wireless medium are Convolutional Turbo Codes (CTC). TPC is used instead of CTC. TPC with eBCH as a constituent code provides further benefits because eBCH codes are decoded easily using the syndrome method and it is used for multiple random error correction. A general comparison for parameters of CTC and TPC is as follows [2]: Code Rate:  CTCs perform best for low code rate applications  TPCs perform best for high code rate applications Data Rate:  CTCs will have difficulty achieving high data rates  TPCs operate at high data rates Error Floor:  CTCs exhibit error floor at BERs below 10 -5  TPCs error floor is less pronounced and at lower BER values TPC provides a performance/complexity trade off and is effectively used in the latest wireless applications to its best capacity. TPC’s have been used with hamming code as constituent coding for various wireless communication applications. TPC using hamming code is been proposed as an optional coding scheme in the 802.16 standard. TPC with BCH code in 802.16 systems is area where work is in progress. Promising features of TPC and BCH codes has led to the motivation to explore its implications in 802.16 systems. International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Published by, www.ijert.org ICIATE - 2017 Conference Proceedings Volume 5, Issue 01 Special Issue - 2017