Noncoherent PN code acquisition with data modulation-on under static and fading environments

Almost all conventional spread-spectrum acquisition schemes assume no data modulation or transition during the acquisition period, because the performance of the acquisition process is significantly degraded when data is present. In practical applications, modulation-off requirements during acquisition period cause inconvenience and delays, such as request and acknowledgment before data transmission can initiate. J. Li and S. Tantarantana (1995) proposed a serial search acquisition scheme with an additional correlator unit to compensate the effect of data modulation-on during acquisition. Because of the complicated quadruple integral equation involved in the analysis of the noncoherent acquisition method, they left the performance analysis of the noncoherent acquisition scheme as a future work. In this paper, the performance of the proposed noncoherent acquisition scheme has been investigated by simulation under static environment. For practical purposes the proposed acquisition scheme is extended to the investigation of the performance under both Rayleigh fading and Doppler frequency shifted fading environments. The simulation results indicate that the proposed noncoherent scheme performs significantly better with data modulation-on than the conventional ones, under both static and fading environments.