Abstract: Long distances transmission in mobile communication is considered serious problem especially in 3rd and 4th generations for mobile systems. In order to keep service efficiency in long distance similar to small distance case, two possible solutions are proposed; first is by applying efficient amplification and equalization stages at receiving end. Second solution is by applying relaying network between source and destination. In this paper two relaying techniques were introduced; amplify and forward (AF) relaying and smart AF relaying. Both mention relaying techniques have been simulated using MATLAB program in case of MIMO CDMA and OFDM systems.

Keywords: MATLAB, MIMO, CDMA, OFDM, amplify and forward (AF), Wireless Sensor Networks (WSN).