Adaptive pilot utilization for OFDM channel estimation in a time varying channel

We propose an architecture for pilot symbol assisted modulation based OFDM systems for estimating the channel in a Rayleigh fading channel. We use deviation of corresponding signals as a parameter to predict the channel characteristics in the transmitter end. We transmit fixed length of test signal to the channel whenever connection setup initiation takes place. Then by using the response, number of pilot signals to insert is determined and correspondingly appended to the data signal. Thus by varying the number of pilots depending upon the channel environment, it certainly improves the channel estimation and reduction in number of pilots used for channel estimation and feedback. This proposed approach differs from the conventional pilot assisted channel estimation in terms of pilot symbols utilization and real time integration between transmitter and receiver without any feedback. Using computer simulations, we showed that the proposed transmitter architecture could achieve a better bit-error-rate (BER) performance in high mobility environment. Furthermore, performance comparisons in terms of BER, average spectral efficiency between proposed method and PSAM based channel estimation in a Rayleigh fading channel is simulated to demonstrate the effectiveness of this approach.