Time and frequency synchronization for CoMP with FBMC

Filter Bank Multicarrier (FBMC) is a multicarrier modulation technique characterized by a prototype filter that can be optimized either in time or in frequency, depending on the target application and/or on the dispersion of the channel. FBMC is often referred as a non-orthogonal modulation technique as symbols overlap in the time domain and as adjacent subcarriers overlap in the frequency domain. This structural absence of orthogonality at the transmitter implies no need for Cyclic Prefix (CP), increasing the bandwidth efficiency of FBMC systems. In cellular systems, Multi-User (MU) downlink cooperation between cells (CoMP) enables to provide a good quality of service to cell edge users while maintaining a high spectral efficiency in the system. For MU-CoMP, time and frequency synchronization between cooperating Base Stations (BSs) and the User Equipment (UE) is a crucial mandatory step. In this study, where synchronization for CoMP with FBMC is considered, it is demonstrated that the UE can robustly estimate very large delays and arbitrary high carrier frequency offsets. The correction of the delays requires only few bits of feedback and the correction of the frequency offset can be entirely realized at the UE side. These results demonstrate that FBMC is a suitable technique for DL CoMP cellular systems.