Packet Transfer System, Radio Base Station, and Packet Transfer Route Optimization Method

• US 20070280192A1
• Filed: 02/17/2005
• Published: 12/06/2007
• Est. Priority Date: 02/18/2004
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Yagyu, Kengo, Takeda, Shinji, Aoki, Hidenori
• Granted Patent: US 8,031,720 B2
• Time in Patent Office: Days
• US Class Current: 370/349
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• 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 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/484 using multiple routing trees
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A fault-tolerant packet transmission system is disclosed that can avoid localized load concentration on a specific portion of a network, while autonomously keeping route optimization, without adding a route control function to non-mesh devices. In a packet transmission system including multiple wireless base stations and one or more terminal devices belonging to one of the wireless base stations, each of the wireless base stations has a location table describing each of the terminal devices associated with a corresponding wireless base station to which the terminal device currently belongs. The wireless base stations exchange the information in the location table with each other to update the location tables and forward a received packet to the next hop along a transmission route toward a destination terminal device.

Claims

1. A packet transmission system comprising:

a plurality of wireless base stations; and

one or more terminal devices belonging to one of the wireless base stations;

wherein each of the wireless base stations has a location table describing each of the terminal devices associated with a corresponding wireless base station to which the terminal device currently belongs, and is configured to exchange the information in the location table with the other wireless base stations to update the location table and to forward a received packet to a next hop along a transmission route toward a destination terminal device.

2. The packet transmission system of claim 1, wherein each of the wireless base stations is configured to broadcast a message reporting participation of a new terminal device when the new terminal device belongs to said wireless base station;

and

wherein upon receiving the message, the other base stations update the location tables.

3. The packet transmission system of claim 1, wherein each of the wireless base stations further has:

a route control table describing each of the other wireless base stations in the network in association with the next hop to which the received packet is to be forwarded if a source terminal device or a destination terminal device currently belongs to one of the wireless base stations.

4. The packet transmission system of claim 3, wherein each of the wireless stations is configured to, upon receiving the packet, search the location table to determine a wireless base station to which the source terminal device or the destination terminal device currently belongs, based on a source address or a destination address contained in the received packet, and to forward the received packet to the next hop according to the route control table.

5. The packet transmission system of claim 3, wherein the received packet contains ID information representing a transmission route used to transmit said received packet or address information representing a wireless base station to which the source terminal device or the destination terminal device currently belongs;

and

wherein each of the wireless base stations is configured to determine the next hop to which the received packet is to be forwarded from the route control table based on the ID information of the transmission route or the address information of the wireless base station contained in the packet.

6. A wireless base station constituting, together with other wireless base stations, a packet transmission system using a wireless packet network, comprising:

a location table describing each of terminal devices currently participating in the network associated with a corresponding one of the wireless base stations to which said terminal device currently belongs;

a route control table describing information items about transmission routes used in the packet transmission system, each information item being associated with one of the other wireless base stations assuming that said one of the other wireless base stations is related to a source or a destination;

a packet receiving unit configured to receive a packet;

a route determination unit configured to determine a route used to transmit the received packet based on information contained in the received packet; and

a packet transmission unit configured to transmit the packet to a next hop according to the route control table.

7. The wireless base station of claim 6, wherein the route determination unit identifies a terminal device indicated by a source address or a destination address contained in the received packet, determines a wireless base station to which the identified terminal device currently belongs with reference to the location table, and finds the next hop in the route control table.

8. The wireless base station of claim 6, wherein the packet transmission unit broadcasts a message packet reporting participation of a new terminal device when the new terminal device belongs to the wireless base station.

9. The wireless base station of claim 6, wherein when the receiving unit receives a message packet reporting a new terminal device having belonged to one of the other wireless base stations, the route determination unit updates the location table.

10. The wireless base station of claim 6, wherein when the receiving unit receives a packet from a source terminal device belonging to this wireless base station, the packet transmission unit writes an address of a destination side wireless base station to which a destination terminal device currently belongs in the packet, and then transmits the packet to the next hop according to the route control table.

11-28. -28. (canceled)