Max-SINR ISI/ICI-Shaping Multicarrier Communication Over the Doubly Dispersive Channel

• Published in: IEEE transactions on signal processing Vol. 55; no. 12; pp. 5782 - 5795
• Main Authors: Das, S., Schniter, P.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Channels; Delay; Demodulation; Design; Design engineering; Detection, estimation, filtering, equalization, prediction; Dispersion; doubly dispersive channel; Equalization; Equalizers; Exact sciences and technology; Information, signal and communications theory; inter- carrier interference (ICI); inter-symbol interference (ISI); Interference suppression; Intersymbol interference; Modulation; Modulation, demodulation; multicarrier; multipath; Prototypes; Pulse modulation; pulse-shape; Signal and communications theory; Signal, noise; Spreads; Statistics; Telecommunications and information theory; Time frequency analysis; time-varying channel; Transmitters; turbo-equalization; wireless communications; wireless communications; multicarrier; doubly dispersive channel; modulation; pulse-shape; multipath; turbo-equalization; Equalization; inter-symbol interference (ISI); time-varying channel; inter- carrier interference (ICI); Performance evaluation; Prototype; Bit error rate; Transmitter; Downlink; Equalizer; Mean square error; Frequency shift; Delay time; Low bit rate; Dispersive channel; Multicarrier; Intercarrier interference; Pulse generation; Multicarrier modulation; Intersymbol interference; Maximum likelihood; Signal to interference plus noise ratio; Pulse shape; Demodulation
• ISSN: 1053-587X; 1941-0476
• DOI: 10.1109/TSP.2007.901660

For communication over doubly dispersive channels, we consider the design of multicarrier modulation (MCM) schemes based on time-frequency shifts of prototype pulses. We consider the case where the receiver knows the channel state and the transmitter knows the channel statistics (e.g., delay spread and Doppler spread) but not the channel state. Previous work has examined MCM pulses designed for suppression of inter-symbol/inter-carrier interference (ISI/ICI) subject to orthogonal or biorthogonal constraints. In doubly dispersive channels, however, complete suppression of ISI/ICI is impossible, and the ISI/ICI pattern generated by these (bi)orthogonal schemes can be difficult to equalize, especially when operating at high bandwidth efficiency. We propose a different approach to MCM pulse design, whereby a limited expanse of ISI/ICI is tolerated in modulation/demodulation and treated near-optimally by a downstream equalizer. Specifically, we propose MCM pulse designs that maximize a signal-to-interference-plus-noise ratio (SINR) which suppresses ISI/ICI outside a target pattern. In addition, we propose two low-complexity turbo equalizers, based on minimum mean-squared error and maximum likelihood criteria, respectively, that leverage the structure of the target ISI/ICI pattern. The resulting system exhibits an excellent combination of low complexity, low bit-error rate, and high spectral efficiency.