Patent ID: 7315536
Filing Date: 2008-01-01
Classification: H04J,H04W

Abstract:
1. A method of adapting radio signal transmission times at a mobile station to enable a base station to synchronously receive radio signals from a plurality of mobile stations, said method accounting for a varying propagation delay between the mobile station and the base station, said method comprising the steps of: measuring a frame reception time at the mobile station for an nth data frame; obtaining timing offset information regarding an offset between the time of transmission of the nth frame and the time of reception of the nth frame; calculating by the mobile station, a transmission time at the mobile station for the nth data frame using the timing offset information and the measured frame reception time at the mobile station for the nth data frame; for an mth data frame later than the nth data frame, determining by the mobile station whether new information on the offset between the times of transmission and reception has been received from the base station; if new timing offset information has been received, calculating by the mobile station, a transmission time at the mobile station for the mth data frame using the new timing offset information and the measured frame reception time at the mobile station for the mth data frame; if new timing offset information has not been received, calculating by the mobile station, the transmission time at the mobile station for the mth data frame based on a change in measured frame reception time between the reception time of the nth data frame and the reception time of the mth data frame, the number of data frames between the nth data frame and the mth data frame, and the timing offset information obtained at the nth data frame, wherein: where: transmitting the mth data frame from the mobile station at the calculated transmission time.