US 6,157,834 AGranted

Terrestrial and satellite cellular network interoperability

AssigneeMotorola, Inc.

InventorsJim E. Helm, Steve Magee, James William Bishop, Jr.

Life of this patent

Estimating the term…

Loading patent…

Abstract

Interoperability between terrestrial cellular systems and satellite based cellular systems allows handoffs between different cellular systems. A call in progress by a subscriber unit (101) over a terrestrial based cellular system (100) which includes a mobile switching center (MSC) (105a) and a plurality of base stations (103a-d) is handed off to a satellite based cellular system (1000) comprising a satellite network (100a, 1001b), a regional gateway (1007) and an interface gateway (1005). A call in progress by subscriber unit (101) over satellite based cellular system (1000) is also handed off to terrestrial based cellular system (100). A dual mode subscriber unit (400) provides switching functionality (409) to switch between transmit modes.

Claims10

Dependent claims

A method for automatic handoff of a subscriber unit telephone call, wherein said subscriber unit is operable with a terrestrial based cellular system and a satellite based cellular system, comprising the steps of:

(a) sending a handoff request from a subscriber unit to a base station of said terrestrial based cellular system, said subscriber unit being operable with said terrestrial based cellular system and said satellite based cellular system;
(b) said base station forwarding said handoff request to a mobile switching center of said terrestrial based cellular system;
(c) forwarding said handoff request to a gateway of said satellite based cellular system;
(d) said gateway determining at least one of said satellites of said satellite based cellular systems to be used by said subscriber unit;
(e) transferring synchronizing messages between said at least one of said satellites and said subscriber unit;
and
(f) establishing a communications channel between said subscriber unit and said at least one of said satellites, wherein handoff from said terrestrial based cellular system and said satellite based cellular system is performed by the interaction between said subscriber unit, said base station, said mobile switching center and said gateway and not primarily by said subscriber unit interacting independently with said base station, said mobile switching center and said gateway.

4 more elements

Dependencies are inferred from the claim text.