About the use of different processing domains for synchronization in non-contiguous FBMC systems

The problem of synchronization in non-contiguous OFDM (NC-OFDM) in the presence of other in-band systems is addressed by means of a comparison between time-and frequency-based signal processing approaches. The filterbank multicarrier scheme with its spectral-efficient offset-QAM (OQAM) OFDM implementation is thereby a good choice for an NC-OFDM system design due to its well-localized spectral signal shape. In this work, we present and discuss two NC-OFDM synchronization methods for OQAM-OFDM, employing the time domain and the already demodulated frequency domain signal for synchronization and evaluate them in terms of sustainable biterror rate over signal-to-interference ratio and variance of time and frequency offset estimation in different resource allocation scenarios. Additionally, their computational complexity is taken into account to estimate the costs of implementation on hardware. The results show that the task of synchronization can be achieved with comparable performance in both domains with an advantage of frequency domain processing over time domain processing in terms of efficiency in preamble design and complexity.