Patent ID: 6418319
Filing Date: 2002-07-09
Classification: H04B,H04W

Abstract:
A method of directing a call to a mobile telephone in a dual-mode cellular-satellite communications network, comprising the steps of:transmitting an alert signal to said mobile telephone using base stations of said cellular network if the mobile telephone is currently registered as active in a cellular network, wherein said alert signal transmitted from said cellular network comprises a first attempt at first power levels and a second attempt at a higher power level; receiving said alert signal at said mobile telephone; transmitting a response to said cellular network as an acknowledgment; upon non-receipt of said acknowledgment by the cellular network within a defined period of time, transmitting a last known location of the mobile telephone from said cellular network to a satellite earth station; upon receipt of said last known location of the mobile telephone at said satellite earth station, using said last known location to determine a satellite antenna beam most likely to be received by said mobile telephone and transmitting an alert signal to said mobile telephone via a satellite using said antenna beam; receiving the alert signal transmitted via the satellite at the mobile telephone; and transmitting a response from the mobile telephone via the satellite acknowledging the alert signal.