Patent ID: 6977919
Filing Date: 2005-12-20
Classification: H04L,H04W

Abstract:
1. A method of efficiently using bandwidth for contention based access and ranging in a time-synchronized communication system, wherein the communication system comprises at least one base station and at least two subscriber units, the method comprising: (a) waiting for a contiguous new access opportunity time window in an uplink channel, the new access opportunity time window being temporally preceded or followed by at least one of a time window reserved for transmission of data from one of the subscriber units and/or a time window reserved for the transmission of data to the base station from two or more of the subscriber units; (b) scanning for an access burst message from a one or more of said subscriber units during the new access opportunity time window, said new access opportunity time window having a duration of at least a duration of the access burst message added to a propagation delay; (c) rejecting all colliding access burst messages received during said new access opportunity time window; (d) acquiring an access burst message from a corresponding subscriber unit during the new access opportunity time window; (e) sending a delay time data value to the corresponding subscriber unit for communication time synchronization; and (f) returning to step (a) if the new access opportunity has expired, else returning to step (b); such that a plurality of access burst messages are acquired from corresponding subscriber units during at least one contiguous new access opportunity time window.