초록 ▼

A system for time division multiplexed communication over a single frequency band in which guard time overhead is reduced by active adjustment of reverse link transmission timing as a function of round trip propagation time. In one embodiment, during a first portion of a time frame, a base station i

A system for time division multiplexed communication over a single frequency band in which guard time overhead is reduced by active adjustment of reverse link transmission timing as a function of round trip propagation time. In one embodiment, during a first portion of a time frame, a base station issues a single burst segmented into time slots comprising data directed to each user station. After a single collective guard time, the user stations respond, one by one, in allocated time slots on the same frequency as the base station, with only minimal guard times between each reception. In order to prevent interference among the user transmissions, the base station measures the round trip propagation time for each user station and commands the user stations to advance or retard their transmission timing as necessary. To establish the initial range of a new user station, a short message is sent by the new user station during the collective guard portion (or, alternatively, during an available time slot), from which the base station calculates the propagation delay and hence the distance of the user station. Messages sent from the base station to the user stations may be interleaved so as to reduce the effects of potential noise or interference.

대표청구항 ▼

[ What is claimed is:] [1.] A method for communicating between a base station and a plurality of user stations comprising the steps oftransmitting from a base station, over a specified frequency band and during an initial portion of a time frame, a plurality of base-to-user messages directed to user

[ What is claimed is:] [1.] A method for communicating between a base station and a plurality of user stations comprising the steps oftransmitting from a base station, over a specified frequency band and during an initial portion of a time frame, a plurality of base-to-user messages directed to user stations, each of said base-to-user messages corresponding to a different base time slot,receiving at said base station from said user stations, over said specified frequency band and during a latter portion of said time frame, a plurality of user-to-base messages directed to said base station, each of said user-to-base messages corresponding to a different user time slot, andtransmitting from said base station, over said specified frequency band and during a subsequent time frame, a timing adjustment command to at least one of said user stations, whereby at least one subsequent user-to-base message from said user station is advanced or retarded in time by an amount specified by said timing adjustment command.