Simulated tolerance for up-link synchronization in fixed wireless access system attaining 8 bit/sec/Hz/cell

This paper evaluates the tolerances of a synchronizing error for the uplink in a fixed wireless access system attaining 8 bit/sec/Hz/cell under the condition of 6-sectored cell. The system adopts CDMA/FDD/16QAM to increase spectral efficiency. In the proposed system, all subscribers attain an error-free condition by power control in the presence of inter-cell interference. The number of subscribers per sector is equal to process gain. Bit rate per subscriber is a multiple of 5 Mbit/s and maximum 20 Mbit/s. We estimate BER performance for the uplink in the presence of synchronizing error such as carrier frequency error and timing error among subscribers in a sector because the errors reduce orthogonality of codes. Simulated BER performance shows that all subscribers in a sector have to have a normalized carrier frequency error of 2% and a normalized timing error of 3% to keep the orthogonality of the codes for the uplink. The feasibility of the synchronization is discussed.