On synchronization in filter bank based OQAM multicarrier transmission

Multicarrier transmission using the OQAM (orthogonally multiplexed quadrature amplitude modulation) technique is characterized by a time offset between the real and imaginary parts of the data symbols, which leads to specific conditions for equalization and synchronization. It is shown that a signal consisting of two offset sinusoids and carried by a dedicated subchannel can serve as a pilot for the synchronization of the receiver. From the complex sequence received in the subchannel, two different control signals can be derived, respectively from the envelope and from the samples themselves after phase equalization. The impact of the analysis filter bank delay on the stability of the feedback loop which controls the timing is studied. Concerning phase equalization, a specific algorithm is introduced and assessed. Experimental results are provided to support the analysis.