Spread-spectrum optical on-off-keying communication system

A model for spread-spectrum communication via a direct-detection optical on-off-keying channel is proposed and investigated. In the proposed model, intensity of the transmitted optical field is modulated by pseudonoise (PN) code and random binary data symbols. An acquisition algorithm motivated by maximum-likelihood (ML) estimation of the phase difference between received and locally generated PN codes is obtained. The ML acquisition algorithm is modified, and a single-threshold acquisition technique is proposed. Performance of the ML acquisition model is obtained in terms of probability of acquisition (P_ACQ). Furthermore, performance of the single-threshold acquisition algorithm is discussed in terms of probability of false alarm (P_FA) and probability of detection (P_D)