Adaptive channel truncation for FFT detection in DMT systems-error component partitioning

FFT block transmissions within a DMT system must be spaced in time to prevent interblock interference (IBI). This transmission spacing causes throughput bit-rate loss. To minimize the dead-time it is necessary to adaptively truncate the channel impulse response to a proportionally small duration. The most common technique adapts the prefilter in a minimum mean-square-error (MMSE) sense to approximate a jointly-designed target response with the fixed desired length. This paper decomposes the error into primary components, where each component addresses a particular adaptation mechanism. As a result it is observed that the MMSE design stalls unnecessarily early. To mitigate this loss, this paper recommends modifications which increase the performance without increasing the computational complexity.