Spectrum efficient eime-domain multiplexing with linear prolate functions

Abstract

In this letter, we propose an orthogonal time-domain multiplexing scheme based on parallel transmission of data symbols modulating linear prolate functions (LPFs). As in orthogonal frequency-division multiplexing (OFDM) systems, equalization is performed in the frequency domain and the cyclic prefix is introduced. As shown in this letter, the overlapping of LPFs in time (and frequency) provides higher degree of sidelobes suppression compared with OFDM. Moreover, it is possible to send more parallel streams in the same bandwidth and time interval (with respect to an OFDM system), by accepting a slight increase of the spectrum "leakage." This letter also proposes the use of these additional streams either to reduce the peak-to-average power ratio or to estimate the channel. Performance comparisons between the proposed system and OFDM are shown for both an additive white Gaussian noise channel and a highly frequency selective channel.