PN code acquisition technique with an adaptive dwell time in DS-SS system

Abstract

This paper proposes an algorithm that improves the mean code acquisition time using an energy estimation mode (EEM) and dwell time values from direct-sequence spread spectrum (DS-SS) System. Until recently, DS-SS System has been used in many areas from Wireless LAN, cellular phone, and GPS to telecommunication. Meanwhile, the development of reducing of pseudonoise (PN) code acquisition time, the core technique of DS-SS system, is continuously explored. The algorithm in this paper added the EEM before a search mode (SM) from the conventional PN code acquisition system, which is composed of a SM and a verification mode (VM). In the EEM, dwell time and threshold values are determined for use in the SM and the VM depending on the correlation energy. This paper applies the proposed technique under Rayleigh-fading channel in performing a simulation of PN code acquisition time by a mathematical modeling to evaluate the proposed algorithm. Numerical results show that the proposed method improves the detection performance and the rejection performance of false code phases not only in the VM but also in the SM. Furthermore, the proposed algorithm reduces the mean code acquisition time by maximum 29% than the conventional algorithm.