Frequency-division spread-spectrum makes frequency synchronisation easy

Frequency division spread spectrum system (FD/S³) has been recently proposed, which uses frequency domain spreading codes and can allow frequency offsets between users. Motivated by the conventional time-domain code acquisition, we propose a frequency (F)-domain code acquisition method using time (T)-domain integrator, which permits frequency offset, which leads to a new T-domain code acquisition using F-domain integrator. Recently proposed Gabor division (GD)/S³ system permits us to use both F- and T-domain code acquisitions separately and cooperatively*.