Packet SS-CDMA modem with carrier frequency offset compensation

A new carrier frequency offset compensation algorithm for packet spread-spectrum code-division multiple-access (SS-CDMA) system is proposed. For evaluation of carrier frequency offset, 11-chip Barker codes were inserted into middle and end of the information block as pilot signals. Rotation direction and rotation amount due to carrier frequency offset are detected by phase differences between a preamble and pilot signals. Using the proposed algorithm, carrier frequency offset is evaluated by single packet. The compensation can be performed under burst transmission. We have evaluated bit error rate (BER) performance of packet SS-CDMA modem with the proposed algorithm by computer simulation. Under carrier frequency offset of less than 0.3 ppm, at the BER of 10/sup -3/, the degradation from the theoretical limit was found to be less than 0.2 dB.