Optimal training sequence and channel estimation method and system for superimposed training based OFDM systems

摘要

The present invention relates to a method for minimizing means square estimation error (MSEE) and bit error rate during channel estimation and equalization between a transmitter and a receiver of an orthogonal frequency division multiplexing (OFDM) systems. The method comprises transmitting from said transmitter to said receiver a training sequence for channel estimation being superimposed onto data at specific pilot to data power ratio (PDPR), receiving the OFDM signals along with the training sequence as an input, cross-correlating said received signal to a specific lag determined by the rms delay spread of the channel, with a specific known training sequence stored in a register, and which is also the sequence that is added to the data at the transmitter in the time domain having a prescribed pilot to data power ratio. The cross-correlated data being processed over a length of samples which can be extended to exploit the coherence time of the channel and processed along with the stored values of the inverse of autocorrelation values of superimposed training (ST) sequence so as to obtain a reliable least squares based channel estimate in a way the PDPR is limited or otherwise. The invention also relates to a system comprising means for computing a time domain least squares (LS) based channel estimate at the receiver.