The International Journal of Research in Engineering Technology and Management (IJRETM)
The transmitter first codes and pre-processes the user data signal prior to transmission. The transmitter Interoperations comprise of bit padding, scrambling, convolutional encoding, data interleaving, sub-carrier modulation mapping, pilot sub-carrier addition and OFDM modulation. Then, the transmitting signal goes through the communication channel. It is the wireless medium that is between the transmitter and receiver, and is modeled by the impulse response of a multipath fading channel and consists of Addictive White Gaussian Noise (AWGN).