초록 ▼

A system and method for time division duplex communication over a single frequency band wherein guard time overhead is reduced by active adjustment of reverse link transmission timing as a function of round trip propagation time. A time frame is divided into a plurality of time slots, during each of

A system and method for time division duplex communication over a single frequency band wherein guard time overhead is reduced by active adjustment of reverse link transmission timing as a function of round trip propagation time. A time frame is divided into a plurality of time slots, during each of which the base station transmits to a user station and the user station transmits to the base station. Communication is initiated by a round trip timing transaction. In response to a general polling message from the base station, a user station seeking to establish communication transmits a short reply message. The base station calculates the distance of the user station by measuring the propagation delay with respect to receipt of the reply message. The base station sends a timing adjustment command to the user station instructing the user station to advance or retard its timing according to the calculated distance, so as to minimize guard times between time slots. Thereafter, the base station monitors the user station transmissions and periodically commands the user station to advance or retard its timing in a like manner. The user station may transmit a control preamble at the start of each time slot to allow the base station to perform round trip timing calculations, and/or to allow adjustment of user station power or antenna selection.

대표청구항 ▼

[ What is claimed is:] [1.] A method of time division duplex communication between a base station and a user station over a single frequency band, comprising the steps oftransmitting from a base station, over a designated frequency band, a user message from a user station directed to a base station,

[ What is claimed is:] [1.] A method of time division duplex communication between a base station and a user station over a single frequency band, comprising the steps oftransmitting from a base station, over a designated frequency band, a user message from a user station directed to a base station,receiving said user message at said base station,calculating at said base station, based on the time of receiving said user message at said base station, a distance of said user station relative to said base station, andtransmitting, over said designated frequency band, a base message from said base station directed to said user station, said base message comprising a timing adjustment command whereby timing of a subsequent message from said user station directed to said base station over said designated frequency band is advanced or retarded, wherein said user station maintains a timing parameter relative to a fixed reference, and wherein said timing adjustment command modifies said timing parameter in order to advance or retard said timing.