Performance analysis of O3BPSK LDD for asynchronous CDMA systems in the presence of synchronization errors

A convenient signaling scheme, termed orthogonal on–off binary phase-shift keying ( BPSK), along with a simple one-shot linear decorrelating detector (LDD), was proposed by Zheng and Barton as a technique for near–far resistant detection in the asynchronous direct-sequence code-division multiple-access (DS/CDMA) systems. The temporally adjacent bits from different users in the received signals are decoupled by using the on–off signaling, and the data rate is maintained with no increase in the transmission rate by adopting an orthogonal structure. This paper examines the effects of three classes of synchronization errors, including time-delay errors, carrier phase errors, and carrier frequency errors, on the performance of the BPSK LDD in an asynchronous CDMA near–far environment. It is shown that the performance of the BPSK LDD has an advantage over that of the isolation bit insertion detector in the presence of synchronization errors. In addition, numerical results show that the BPSK LDD still offers a good near–far resistant property as long as synchronization errors do not exceed some practical limit.