International Journal of Research Studies in Science, Engineering and Technology [IJRSSET] Volume 1, Issue 2, May 2014, PP 60-66 ©IJRSSET 60 M-Psk Based OFDM Simulation in Wireless Communication Systems M.Raju 1 , K. Ashoka Reddy 2 1 Ph.D Research Scholar, Kakatiya University, Warangal, A.P., INDIA m.raju2002@gmail.com 2 Professor, E & I Department, KITS, Warangal, A.P., INDIA reddy.ashok@yahoo.com Abstract: Orthogonal frequency division multiplexing (OFDM) is a special case of multicarrier transmission and frequency division multiplexing, where a single data stream is transmitted over several lower rate subcarriers, placed orthogonal to each other. Today it has become the chosen modulation technique for wireless communications. It can provide large data rates with optimum bit error rate and enough robustness to radio channel impairments. In this paper, a complete M-PSK based OFDM simulation is carried out, to analyze the performance of OFDM system in terms of Bit Error Rate (BER), Average Phase Error (APE), Average Root Mean Square (ARMS) values of OFDM signal at the entrance and exit of the channel and Percent error of pixels of the received image. BPSK, QPSK, 16PSK, 256PSK techniques are analyzed in reference to OFDM processing. Keywords: OFDM, BER, PER, PAPR, PIXEL ERROR, PSK 1. INTRODUCTION Orthogonal Frequency Division Multiplexing (OFDM) is an attractive technology for Wireless Communications which is one of Multi Carrier Modulation (MCM) techniques, offers a considerable high spectral efficiency, multipath delay spread tolerance, immunity to the frequency selective fading channels and power efficiency [1], [2]. As a result, OFDM has been chosen for high data rate communications and has been widely deployed in many wireless communication standards such as Digital Video Broadcasting (DVB), Digital Audio Broadcasting (DAB) and based mobile worldwide interoperability for microwave access (mobile WiMAX) based on OFDM access technology [3]. In a single carrier communication system, the symbol period must be much greater than the delay time in order to avoid inter-symbol interference (ISI) [4]. Since data rate is inversely proportional to symbol period, having long symbol periods means low data rate and communication inefficiency. A multicarrier system, such as Frequency Division Multiplexing (FDM), divides the total available bandwidth in the spectrum into sub-bands for multiple carriers to transmit in parallel [5]. An overall high data rate can be achieved by placing carriers closely in the spectrum. However, inter-carrier interference (ICI) will occur due to lack of spacing to separate the carrier. To avoid inter-carrier interference, guard bands will need to be placed in between any adjacent carriers, which results in lowered data rate. OFDM (Orthogonal Frequency Division Multiplexing) is a multicarrier digital communication scheme to solve both issues. It combines a large number of low data rate carriers to construct a composite high data rate communication system. Orthogonality gives the carriers a valid reason to be closely spaced, even overlapped, without inter-carrier interference. Low data rate of each carrier implies long symbol periods, which greatly diminishes inter-symbol interference. Although the idea of OFDM started back in 1966 [6], it has never been widely utilized until the last decade when it “becomes the modem of choice in wireless applications” [7]. It is now interested enough to experiment some insides of OFDM. The objective of this paper is to demonstrate the concept and feasibility of an OFDM system, and investigate how its performance is changed by varying some of its major parameters. This objective is met by developing a MATLAB program to simulate a basic OFDM system. From the process of this development, the mechanism of an OFDM system can be studied; and complete characteristics of an OFDM system can be explored.