Design of Selectable Modems for MC-CDMA Based on Software Defined Radio

Abstract

MC-CDMA technique is the combination of Orthogonal Frequency Division Multiplexing (OFDM) technique and Code Division Multiple Access (CDMA) technique and collects the benefits of both techniques to provide higher data rates and greater flexibility for voice, data, video and internet services for future wireless systems. In this paper MC-CDMA system based on Software Defined Radio (SDR) was proposed. The proposed data spread model consists of gold code and Selectable six modulation types (BPSK, QPSK, 8QAM, 16QAM, 32QAM and 64QAM). In addition, OFDM is designed by both FFT and IFFT for detecting ideal channel. The programming is done by using MATLABSimulink tool as well as M-files presented for each modem. Matlab 13A. The transmitter send 4, 3 and 2 bit to the receiver in which the system indicate is too big for 4 and 3 bit therefore the transmitted but reduced to two bit for successfully system work. To achieve optimum encoding and decoding signal the all modulation techniques use 5 MHz to 20 MHz spectrum frequency. Moreover the bandpass signal generation has optimal utilized area to satisfy the required sampling rate