Two-stage acquisition for time-hopping impulse radio communications

Time-hopping impulse radio is a promising radio technology for networks delivering extremely high data rates at short ranges. But the use of extremely short duration pulses makes synchronization task more difficult. In this paper a novel acquisition with two-stage serial search noncoherent correlator for ultra wideband signal is proposed. This acquisition scheme gets chip timing synchronization, and aligns phase of the local time-hopping code in two stages successively. With the aid of flow-graph approach, the analytical expressions have been presented for the mean acquisition time and probability of acquisition. Numerical results in a slow fading channel show that the novel two-stage acquisition method can offer much shorter mean acquisition time and much higher probability of acquisition than that of the conventional acquisition.