METHOD AND APPARATUS FOR MULTIPLE ACCESS COMMUNICATION

A communication system and method requiring minimal adaptation of TDD equipment to support an FDD frame structure, includes a novel frame structure by which a plurality of user stations, each having a single frequency synthesizer, communicate with a base station. According to the frame structure, a time frame comprises a plurality of time slots each divided into a first time segment and a second time segment. Transmissions from user stations are sent over the user transmission frequency band, and alternate in time with transmissions from the base station sent over the base transmission frequency band in a manner to provide adequate transmit/receive switching time for the user stations. The user stations preferably transmit to the base station in the first time segment of a time slot, and the base station preferably transmits in the second time segment of a time slot, such that the base station and user stations do not transmit simultaneously. In one embodiment, a duplex communication includes a user station transmission and a base station transmission in adjacent time slots. In an alternative embodiment, a duplex communication includes a user station transmission separated by approximately one-half the time frame from the base station transmission. User stations and/or base stations originally configured for TDD communication can be adapted or modified to support the various FDD frame structures of the present invention with minimal reconfiguration to the software and/or hardware.