A new algorithm for joint impulse response shortening in DMT systems

Abstract

In discrete multitone (DMT) systems, a cyclic prefix (CP) is inserted between transmitted symbols to eliminate the intersymbol interference (ISI). When the CP length is smaller than the channel order, a time domain equalizer (TEQ) can be used to shorten the channel impulse response. For full-duplex DMT systems with overlapped upstream band and downstream band, an echo canceller is needed to separate the signals transmitted in opposite directions. The complexity of the echo canceller is proportional to the length of the echo impulse response. This paper proposes a new algorithm for these full-duplex DMT systems that is able to reduce the effective channel and echo impulse responses using a single TEQ filter. Computer simulations show that the proposed algorithm has better throughput performance for the channel path and better generalized signal-to-interference ratio for the echo path than some existing algorithm.