Transient response of two-level coarse code acquisition scheme in spread spectrum radio

A modified two-level coarse code acquisition scheme for spread-spectrum radio is presented and analyzed. The first reason for the modification of the known schemes (see S.S. Rappaport and D.L. Schilling, IEEE Trans. Commun., vol.COM-28, no.9, 1734-42, Sept. 1980, and N.D. Wilson et al., IEE Proc., vol.135, pt.F, no.1, 95-104, Feb. 1988) was to simplify hardware realization and to make easier the practical application of the scheme. As a side product the authors describe a method for serial FH (frequency-hopping) signal acquisition by which the average synchronization time is considerably reduced compared with the known serial algorithms. The second reason was to incorporate an active automatic threshold control scheme in the receiver and to make the entire system more realistic. Theoretical performance analysis is focused on the problem of threshold-setting optimization.