Characterization of Sector Clock Biases in Cellular CDMA Systems

The clock bias of cellular code division multiple access (CDMA) base transceiver station (BTS) sectors is characterized. The clock biases of individual sectors and the discrepancy between the clock biases of different sectors of the same BTS cell are studied. If not modeled and accounted for appropriately, this discrepancy could be harmful when cellular CDMA signals are exploited for navigation, introducing tens of meters of error in the position and tens of nanoseconds of error in the receiver’s clock bias estimate. A model for the discrepancy is proposed and validated through extensive experiments at different locations and times. Finally, an empirical upper bound on the discrepancy between the sector clock biases is provided.