| 摘要 |
The invention provides a frequency control method and apparatus for efficiently controlling in a wireless system the carrier frequency of a received signal transmitted over a radio link to counteract carrier frequency drifts in the received signal and hence maintain link connectivity. In a preferred embodiment, the invention provides upstream and downstream carrier frequency control in a broadband wireless access (BWA) time division multiplex access (TDMA) system formed of a base transceiver station (BTS) and multiple customer premises equipment (CPE) units. At each of the CPE units, the CPE upstream carrier frequency is preemptively adjusted based on downstream carrier frequency measurements to counteract carrier frequency variations in the upstream carrier frequency. For downstream communications, the BTS periodically polls all active CPE units to obtain downstream frequency offset estimates, calculate a frequency correction offset and adjust the downstream carrier frequency accordingly. |
