Turbo Coded OFDM with Large Number of Subcarriers

Wireless communication systems have greatly advanced during the last years. A significant contributor in these systems’ performance has been Orthogonal Frequency Division Multiplexing (OFDM). Since its invention, it is considered to be a technological leap. This leap in splitting an information stream in multiple frequency carriers has been adapted by various scientists working on the development of wireless systems. Moreover, as OFDM presented excellent tolerance of channel fading and noise signals, the evolvement in terms of speed and reliability was consequent, because only a small stream of information is lost due to noise effects. OFDM along with the knowledge that Turbo codes is another excellent scheme of reducing BER, has triggered us to expand our research. So, we experimented in simulation level not only in joining OFDM with Turbo Codes but even in finding a better Turbo scheme compared to a typical PCCC, SCCC and a Convolutional encoder with Viterbi decoder. As the last goal has already been accomplished, in this paper is presented the new OFDM system consisted of our Turbo scheme. The analysis of the previous system took into consideration the effects of an AWGN channel. Also, this noise analysis was conducted using a simulation platform with specific attributes such as transmitting and receiving fixed number of subcarriers (2048 carriers after IFFT block) while using different types of convolutional concatenated codes, such as PCCC (Parallel), SCCC (Serial) and the new PCCC scheme. The results clearly show not only the improvement in the BER performance of the Turbo Coded OFDM systems (compared to others consisted of Viterbi decoders) but the overall superiority of the proposed design.

[1]  Ibrahim S. Raad,et al.  Implementation of a turbo codes test bed in the Simulink environment , 2005, Proceedings of the Eighth International Symposium on Signal Processing and Its Applications, 2005..

[2]  Hu Guijun,et al.  Application of Turbo codes in optical OFDM multimode fiber communication system , 2008 .

[3]  Vasilis Raptis,et al.  Design and Implementation of Ultra‐Wideband Impulse Radio Transmitter , 2010 .

[4]  Kms Soyjaudah,et al.  Comparative Study of Turbo Codes in AWGN Channel Using MAP and SOVA Decoding , 2001 .

[5]  Georgios B. Giannakis,et al.  Cyclic prefixing or zero padding for wireless multicarrier transmissions? , 2002, IEEE Trans. Commun..

[6]  M. K. GUPTA,et al.  TO IMPROVE BIT ERROR RATE OF TURBO CODED OFDM TRANSMISSION OVER NOISY CHANNEL , 2009 .

[7]  Matthieu Finiasz,et al.  Methods for the reconstruction of parallel turbo codes , 2010, 2010 IEEE International Symposium on Information Theory.

[8]  Panos Kostarakis,et al.  Design and Analysis of a Multiple-Input Receiver for Mimo Wireless Applications , 2010, Int. J. Commun. Netw. Syst. Sci..

[9]  A. Glavieux,et al.  Near Shannon limit error-correcting coding and decoding: Turbo-codes. 1 , 1993, Proceedings of ICC '93 - IEEE International Conference on Communications.

[10]  S. Nagarani,et al.  A Survey on Space-Time Turbo Codes , 2010, ArXiv.

[11]  Sooyoung Kim,et al.  A new result on turbo coded QO-STBC schemes , 2010, IEEE Communications Letters.

[12]  Vahid Tarokh,et al.  Near Shannon Limit and Low Peak to Average Power Ratio Turbo Block Coded OFDM , 2011, IEEE Transactions on Communications.

[13]  Jonas Svedberg,et al.  Forward error correction coding for the language , 2001 .

[14]  Sergio Isla Hernandez.  Simulation and Evaluation of a DVB System using Simulink (Vol. I) , 2005 .

[15]  Hermann Rohling,et al.  OFDM: Concepts for Future Communication Systems , 2013 .

[16]  Stephan Pfletschinger,et al.  Iterative demapping for OFDM with zero-padding or cyclic prefix , 2004, 2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577).

[17]  Vasilis Raptis,et al.  In depth analysis of noise effects in orthogonal frequency division multiplexing systems, utilising a large number of subcarriers , 2010 .

[18]  Sergio Benedetto,et al.  A soft-input soft-output maximum a posteriori (MAP) module to decode parallel and serial concatenated codes , 1996 .

[19]  Panos Kostarakis,et al.  Design and Measurements of a Multiple-Output Transmitter for MIMO Applications , 2011, J. Circuits Syst. Comput..

[20]  Teong Chee Chuah,et al.  Robust turbo coded OFDM transceiver for power-line channels , 2010, IEICE Electron. Express.

[21]  Alberto Pastor Prieto.  Simulation and evaluation of a DVB System using Simulink (Vol. II) , 2005 .

[22]  Giorgos Tatsis,et al.  Turbo Codes―A New PCCC Design , 2011 .

[23]  P.G.M. de Bot.  Design of a digital communication system using multistage block coded modulation , 1991 .

[24]  Rudiger Urbanke,et al.  Exchange of Limits: Why Iterative Decoding Works , 2011, IEEE Trans. Inf. Theory.

[25]  Stephen B. Wicker,et al.  Turbo Coding , 1998 .

[26]  Andrew J. Viterbi,et al.  An Intuitive Justification and a Simplified Implementation of the MAP Decoder for Convolutional Codes , 1998, IEEE J. Sel. Areas Commun..

[27]  B.L. Evans,et al.  A real-time embedded software implementation of a turbo encoder and soft output Viterbi algorithm based turbo decoder , 2002, Conference Record of the Thirty-Sixth Asilomar Conference on Signals, Systems and Computers, 2002..

[28]  Masahiro Morikura,et al.  New high-rate wireless LAN standards , 1999, IEEE Commun. Mag..

[29]  S. Choudhury.  Modeling and Simulation of a Turbo Encoder and Decoder for Wireless Communication Systems , 2002 .

[30]  Vasilis Raptis,et al.  Enhanced PAPR in OFDM without Deteriorating BER Performance , 2011, Int. J. Commun. Netw. Syst. Sci..

[31]  B. Walke,et al.  Integration of COFDM Systems with Multiple Antennas and Design of Adaptive Medium Access Protocols , 2010 .

[32]  P. Odling,et al.  The cyclic prefix of OFDM/DMT - an analysis , 2002, 2002 International Zurich Seminar on Broadband Communications Access - Transmission - Networking (Cat. No.02TH8599).

[33]  Vasilis Raptis,et al.  Performance of UWB‐Impulse Radio Receiver Based on Matched Filter Implementation with Imperfect Channel Estimation , 2010 .

[34]  Pierre Duhamel,et al.  From maximum likelihood to iterative decoding , 2011, 2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP).