Biwindowed Discrete Multitone Transceiver Design

A family of biwindowed discrete multitone (DMT) transceivers that provide both subchannel spectral containment at the transmitter and spectral selectivity at the receiver is proposed. These systems have the attractive feature that they provide spectral shaping at both ends of the transceiver without requiring the cyclic prefix to be longer than the order of the channel impulse response. The windows are designed in a channel independent manner and are constrained to produce subchannel outputs that are free from (intrasubchannel) intersymbol interference (ISI). Furthermore, the design allows the intersubchannel interference (ICI) to be controlled in such a way that it can be mitigated using a relatively simple minimum mean-square error (MMSE) successive interference cancellation scheme. Under a realistic model for a digital subscriber line (DSL) environment, the achievable bit rate of the proposed system is significantly higher than that of the conventional DMT system and some established windowed DMT systems with receiver-only windowing. This performance gain is a result of the capability of the proposed system to combat the near-end crosstalk (NEXT) at the transmitter and receiver and to mitigate the narrowband noise at the receiver, without the requirement of excess cyclic prefix.