Copyright © 2018 Yanita Shrimali et. al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. International Journal of Engineering & Technology, 7 (4.5) (2018) 665-668 International Journal of Engineering & Technology Website: www.sciencepubco.com/index.php/IJET Research paper VHDL Implementation of low power turbo coded OFDM physical layer for wireless communication Yanita Shrimali 1 *, Janki Ballabh Sharma 1 , R. S. Meena 1 1 Department of Rajasthan Technical University, kota *Corresponding author E-mail: shrimaliyanita@gmail.com Abstract Orthogonal Frequency Division Multiplexing (OFDM) is exceptionally favored system for rapid information transmission over remote channel. In this paper, VHDL implementation of low power turbo-coded OFDM (TCOFDM) Physical layer architecture is presented. In this architecture a low power memory-less pipelined FFT processor and Log-map turbo encoder/decoders are used to provide high through- put and lower complexity. Log-map turbo decoder provides high speed with good error correction capacity, while FFT/IFFT processor with single delay feedback (SDF) memory less architecture provide improved area and power efficiency. Proposed TCOFDM system is implemented using Xilinx ISE Design suite in the simulation results shows that the proposed scheme is having low power, high speed, high throughput and smaller area in comparison to other schemes. Keywords: Turbo Coding; OFDM; FFT/IFFT. 1. Introduction Because of quick development of remote and sight and sound cor- respondence, there is an enormous requirement for fast information rate transmission. To enhance the speed and greatest measure of in- formation transmission Orthogonal Frequency Division Multiplex- ing (OFDM) framework have been produced. These systems like- wise require quick execution of countless, which can bring about high power utilization. In this paper, we concentrate on a low power OFDM outline. [1] OFDM system and its physical layer VHDL implementation using different modulation scheme such as Quadrature Phase Shift Key- ing (QPSK)[10],Quadrature Amplitude Modulation (QAM)[4], Bi- nary Phase Shift Keying (BPSK)[1] and various channel scheme e.g. Forward error coder (FEC)and Viterbi encoding/decoding based[3,4,5] have already been developed. Recently in order to achieve high throughput of OFDM system using Turbo coding scheme [6-11] has been used. However, for turbo coding SOVA and Map [14] decoding algorithm have been developed. But, Map algorithm improved decoding speed, BER (Bit Error Rate) and sys- tem complexity. VHDL implementation of SOVA based and Log- Map based turbo coder have already been reported in [6-9] FFT processors are the key of OFDM physical layer system. Dif- ferent architecture of FFT processor has been reported for efficient OFDM. These architecture include parallel [14] and pipelined [12] implementation such as multi-path delay feedback (MDF), single- path delay feedback (SDF)[12],memory based[13] and memory less[12].In [13] an efficient 64 pipelined FFT engine has been in- troduced using single path delay feedback scheme. In [12] a memory less architecture with low space requirement has been pre- sented. Since the use of turbo coder with FFT provide high through- put therefore a software (matlab) based scheme for TCOFDM phys- ical layer has been reported in [13] Therefore, in this paper, VHDL implementation of low power Turbo coded OFDM physical layer with efficient FFT/IFFT proces- sor is presented. In this proposed work Turbo coder with Map algo- rithm and SDF based memory less FFT processor are used to im- prove the performance of OFDM physical layer. Pro- posed TCOFDM system is implemented using Xilinx ISE Design suite 14.2 and the simulation results compare with [5], [7] and [9]. Com- parison results verify the efficiency of proposed system. The rest of the paper is organized as follow. First, a brief re- view of OFDM system Model in section 2. Proposed Low power TCOFDM architecture details are describe in section 3. System per- formance, synthesis and simulation results are discussed in section 4. Finally, section 5 concludes the work. 2. OFDM system model OFDM procedure is one of the multiple subcarrier transmission procedures. The fundamental rule of OFDM is isolate a high in- formation rate stream into low information rate streams and trans- mit them in parallel [1-2].OFDM, range is isolated into sub bearers every one being regulated at bring down information rates. OFDM system is divided into three main sections: transmitter, receiver and channel. The main component of the OFDM system are encoder/ decoder[9], modulator/ demodulator, IFFT/ FFT, parallel o serial and serial to parallel convertor are shown in Fig- ure 1 .Input data is convert into time domain by IFFT in transmit- ter section and FFT convert output data into frequency domain in receiver section of OFDM system[10-11].