Adaptive Coded Modulation for OFDM System

This paper studies the adaptive coded modulation for OFDM system using punctured convolutional code, channel estimation, equalization and SNR estimation. The estimation based on block type pilot arrangement is performed by sending pilots at every sub carrier this a specific number of following symbols. Signal to noise ratio estimated receiver then transmitted transmitter through feedback ,the according select appropriate scheme coding rate which maintain constant bit error ratelower than requested BER. Simulation results show that better performance confirmed target (BER) (10-3) as compared conventional schemes, offers gains 5 dB uncoded state BER 10-3. proposed maintains fixed under changing conditions.