Adaptive acquisition of PN sequences for DSSS communications

Since the received signal levels in mobile communications are unknown and location varying, acquisition schemes for pseudonoise (PN) sequences with fixed thresholds cannot provide satisfactory performance. This fixed-threshold scheme may cause too many false alarms or result in low detection probability for a selected threshold value. In this letter we present an adaptive acquisition scheme for PN sequences which estimate the background power level, multiply it with threshold coefficient to keep the false alarms constant, and use it as a threshold. Index Terms - Adaptive acquisition, pseudonoise sequence, spread-spectrum communication.