Phase-Noise Analysis of Overlapping Filtered Multitone Waveforms in Millimeter-Wave Radio Systems

Future wireless networks demand multicarrier modulation schemes with improved spectrum efficiency and superior spectrum containment. Orthogonal frequency-division multiplexing (OFDM) has been the favorite technique, but due to its poor spectrum containment, various alternative schemes are under consideration. This paper focuses on the filtered multitone (FMT) scheme, one of the classical filter-bank multicarrier (FBMC) schemes utilizing QAM subcarrier symbols. In contrast to OFDM and the widely-studied FBMC/OQAM, FMT does not reach maximum spectrum density of subcarriers because non-overlapping subcarriers are required to reach orthogonality. In recent work, we have studied FMT with overlapping subcarriers to reach improved spectrum density, with the conclusion that significant overlap can be tolerated, depending on the required signal-to-interference ratio. Subcarrier overlap allows to increase the roll-off of the subcarrier frequency responses, which greatly simplifies the filter-bank implementation. In this paper we investigate the effects of phase-noise, in combination with intercarrier interference introduced by the subcarrier overlap. Phase-noise is particularly critical in millimeter-wave operation, which is a central element in future systems. We show that FMT has potential for significantly improving the performance under phase-nose. Flexible fast-convolution based scheme is applied for FMT generation and receiver processing, and the tradeoffs in the parametrization of overlapping FMT are characterized using practical phase-noise models.