Joint window and time domain equalizer design for bit rate maximization in DMT-receivers

• Published in: IEEE transactions on signal processing Vol. 53; no. 3; pp. 1132 - 1146
• Main Authors: Ysebaert, G., Vanbleu, K., Cuypers, G., Moonen, M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-03-2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Bit rate; Bit rate maximization; channel shortening; Data communication; Design methodology; Detection, estimation, filtering, equalization, prediction; Digital subscriber line; DSL; Equalizers; Exact sciences and technology; Frequency domain analysis; Information, signal and communications theory; Mean square error methods; Mean square errors; Modems; multicarrier modulation; narrowband interference; OFDM modulation; RFI; Signal and communications theory; Signal, noise; Studies; Telecommunications and information theory; time-domain equalization; Upper bound; windowing; time-domain equalization; windowing; Bit rate maximization; Frequency domain method; Receiver; Multitone system; Equalization; Optimization; Digital transmission; Multicarrier modulation; channel shortening; Time domain method; Simulation; RFI; Digital subscriber line; Digital communication; narrowband interference
• ISSN: 1053-587X; 1941-0476
• DOI: 10.1109/TSP.2004.842213

In discrete multitone (DMT) receivers, as for instance in asymmetric digital subscriber lines (ADSLs), the classical equalizer structure consists of a (real) time domain equalizer (TEQ) combined with complex 1-tap frequency domain equalizers (FEQs). Additionally, receiver windowing can be applied to mitigate the bad spectral containment of the demodulating DFT sidelobes. We focus on a combined equalizer and windowing design procedure to maximize the achievable bit rate in DMT-based modems. Whereas the combination of a TEQ with a single window treats all the data carrying tones in a common way, the presented design method can also be used in a "per group" fashion, where smaller groups of tones receive each a different equalizer-window pair. When such groups contain only one single tone, the design procedure can be linked to the performance of an unbiased minimum mean square error (MMSE) per tone equalizer (PTEQ), which then also implicitly implements a per tone window. The general framework introduced Allows us to treat equalizer-only and window-only designs as well, which appear as special cases in a natural way. This set of bit rate maximizing techniques can serve either as practical design methods or as upper bounds for existing (suboptimal) methods. We will also show that for the same achievable bit rate, equalizer taps can be exchanged for windowing coefficients to reduce complexity during data transmission.