Channel Shortening

Inter-Block Interference Suppression in OFDM Transmission

Abstract

In high-speed OFDM transmission, inter-block interference degrades the system performance when the impulse response length of a frequency-selective channel is longer than expected. This article explains the concept and specific methods of channel shortening, which uses time-domain linear filters to reduce the effect of inter-block interference. First, we describe channel-shortening methods for the case where the channel is known to the receiver. Next, we introduce blind channel-shortening methods, which determine filters without pilot symbols or knowledge of the channel.