Packet switching architecture in cellular radio

• US 6,219,346 B1
• Filed: 12/02/1997
• Issued: 04/17/2001
• Est. Priority Date: 12/02/1997
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Maxemchuk, Nicholas Frank
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): Pizarro, Ricardo M.
• Application Number:
  US08/982,634
• Time in Patent Office: 1,232 Days
• Field of Search: 370/338, 370/328, 370/335, 370/342, 370/349, 370/351, 370/402, 370/406, 370/310, 370/329, 370/331, 370/375
• US Class Current: 370/338
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

Improved performance is achieved for cellular systems with an arrangement where mobile units transmit information in packet format. A base station routes received packets to switching agents identified by the packets, and the switching agents forward the information contained in the packets to a wired network. The switching agent thus forms the interface between the packet switched portion of the cellular system and the wired network, which may be a circuit switched network. The routing of packets to switching agents allows the system to dedicate one agent to each mobile unit known to the system. It also allows a mobile unit'"'"'s switching agent to remain wherever it is hosted even when the mobile unit moves from cell to cell, causing different base stations to receive the mobile unit'"'"'s packets. The routing of packets is achieved with a routing network, which preferably is immune to single failures. In one illustrative embodiment, the routing network comprises a mesh network that interfaces a multiply connected routing network.

Claims

1. A system including a wired network and a cellular network, comprising:

a plurality of base stations to receive information from mobile stations in the form of packets;

a wired packet switching network to which said base stations are connected, for receiving said packets sent by mobile units to said base stations, where each of said packets contains a switching agent address;

a plurality of software switching agents interposed between the wired packet switching network and said wired network, where each switching agent is associated with a registered mobile unit in said cellular network, and

where a mobile unit in said cellular network communicates with its associated switching agent via packets that are explicitly addressed to said associated switching agent.

2. The system of claim 1 where a switching agent communicates with its associated mobile unit with encapsulated packets addressed to a base station, where each encapsulated packet contains a packet addressed to said associated mobile unit.

3. The system of claim 1 where said wired network is a circuit switched network.

4. The system of claim 1 where said wired network is a packet switching network.

5. The system of claim 1 where said wired packet switching network comprises a plurality of service areas, with each of said areas including a “

central office”

node onto which packets from certain base stations normally home, said system thereby having a plurality of “

central offices”

.

6. The system of claim 5 where each of the “

central offices”

includes means for migrating said switching agents from one “

central office”

to another “

central office”

.

7. The system of claim 6 where the means for migrating includes communication lines that interconnect said “

central offices”

.

8. The system of claim 6 where said means for migrating refrains from migrating a switching agent from one “

central office”

of said plurality of “

central offices”

to another “

central office”

of said plurality of “

central offices”

when a mobile unit associated with said switching agent moves from one cell that homes on said one “

central office”

to another cell that homes on said another “

central office”

.

9. The system of claim 6 where said means for migrating migrates a switching agent from one “

central office”

of said plurality of “

central offices”

to another “

central office”

of said plurality of “

central offices”

when a mobile unit associated with said switching agent moves from one cell that homes on said one “

central office”

to another cell that homes on said another “

central office”

.

10. The system of claim 5 where the switching agents are software objects.

11. The system of claim 5 where the switching agents convert the format of packets received from base stations into a format that is compatible with the format employed in said wired network.

12. The system of claim 5 where said each switching agent of an active mobile unit represents said unit to said wired network.

13. The system of claim 5 where said switching agents send packets addressed to mobile units, and where said packets are encapsulated in larger packets addressed to base stations.

14. The system of claim 1 where said wired packet switching network comprises:

a plurality of nodes coupled to said switching agents,

a router network comprising interconnected routers that is connected to said plurality of nodes, and

a packet routing network having a first plurality of ports that are connected to routers within said router network, a second plurality of ports that are connected to said base stations, wherein said packet routing network has more than one path from said first plurality of ports to said second plurality of ports, and vice versa.

15. The system of claim 14 where said packet routing network is a mesh network.

16. The system of claim 14 where said packet routing network is a Manhattan Street Network.

17. The system of claim 1 where each switching agent is associated with a single registered mobile unit in said cellular network.