Channel Shortening for doubly selective channels using TEQ, MMSE and LMS

—In discrete multitone (DMT) transceivers an intelligent guard time sequence, called a cyclic prefix (CP), is inserted between the symbols to ensure that samples from one symbol do not interfere with the samples of another symbol. The length of the CP is determined by the length of the impulse response of the effective physical channel. Using a long CP reduces the throughput of the transceiver. To avoid using a long CP, a short time-domain finite impulse response filter (FIR) is used to shorten the effective channel impulse response. This paper addresses how to perform calculation for the coefficients of SIRF using Equalization techniques, how to design doubly selective channels and their shortner. The algorithms presented in this paper approach the problem of equalization for long channel in perspective of impulse response shortening. The simulation results show the better result for the Adaptive White Gaussian Noise (AWGN) channel and which perform better for doubly selective channels. Minimum mean square error (MMSE) equalizer is best known and performs well, so the MMSE equalizer is use and reformulates it for channel shortening equalizer.