Impulse compression for OFDM transmission over time-varying multipath channels

Abstract

In today's multicarrier modulation systems such as orthogonal frequency division multiplexing (OFDM) a circular extended guard interval is inserted between successive multicarrier symbols in order to reduce intersymbol and interchannel interference. The length of the guard interval is determined by the length of the channel impulse response. In this paper, we consider an equalizer to compress the channel impulse response for OFDM transmission. Due to the compression effect, the guard interval can be reduced and the efficiency of the OFDM system increases. The system performance is demonstrated for transmission over several time-varying multipath channels with additive white Gaussian noise (AWGN).

Variable Guard Interval Orthogonal Frequency Division Multiplexing in Dynamic Channel Condition

“…In [12], the authors propose not to use GI, but this is from synchronization perspective and does not consider the impact of ISI. [13] provides method for equalization where a filter is designed which on convolution with the channel yields an effective channel with a compressed impulse response. This method is elegant but would increase the receiver complexity.…”