PN code acquisition for the spread-spectrum optical on-off-keying communication system

A model for spread-spectrum (SS) communication using a direct-detection optical on-off-keying (OOK) channel is proposed and investigated. In this model, the intensity of the transmitted optical field is modulated by a pseudonoise (PN) code and random binary data symbols. Two PN code acquisition models, namely the maximum-likelihood (ML) and the single dwell-time (SDT) models, are proposed. The performances of the ML and the SDT models are obtained in terms of the probability of missed acquisition, the probability of false alarm, and the probability of missed detection under the Gaussian approximation. The mean acquisition times are obtained and used to provide a comparison between the proposed ML and SDT models