Packet transfer system, radio base station, and packet transfer route optimization method

• US 8,031,720 B2
• Filed: 02/17/2005
• Issued: 10/04/2011
• 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: Takeda, Shinji, Yagyu, Kengo, Aoki, Hidenori
• Primary Examiner(s): Moe; Aung S
• Assistant Examiner(s): Elliott, IV; Benjamin H
• Application Number:
  US10/590,033
• Publication Number:
  US 20070280192A1
• Time in Patent Office: 2,420 Days
• Field of Search: 370/349, 370/351, 370/255, 370/256, 370/285, 370/331, 370/386, 370/395.3, 370/395.31, 370/400, 370/401, 370/408, 370/475, 370/485, 370493-495, 455/436, 455/440, 455/445, 455/456.1, 455/456.5, 455/456.6, 455/560, 455/561
• US Class Current: 370/395.31
• 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 to record an address of each of said plurality of wireless base stations that structure a network, and for each of said plurality of wireless base stations that are recorded, addresses of the terminal devices that are currently existing under the respective wireless base station,

a short packet route control table and a long packet route control table that indicate for each of the other wireless base stations that structure the network which wireless base stations are along a first route for a short packet and along a second route for a long packet, and wherein

each of the wireless base stations is configured to exchange the information in the location table with the other wireless base stations to update the location table; and

each of the wireless base stations is configured to, upon receiving a packet, identify a wireless base station to which the source terminal device or the destination terminal device currently belongs according to the location table, based on a source address of the source terminal device or a destination address of the destination terminal device, respectively, included in the received packet, and to determine whether the packet is a short packet or a long packet to find a next hop based on either the short packet route control table or the long packet route control table, respectively, to find the next hop, and transmit the packet to the next hop.

2. The packet transmission system according to claim 1, wherein at least one of the wireless base stations includes:

a cost estimation unit configured to send a route search packet to adjacent wireless base stations that configure the network so that the adjacent wireless base station add up route costs to gather information on the first route and the second route for the short packet route control table and the long packet route control table, respectively.

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

a location table to record an address of each of the wireless base stations in said packet transmission system, and for each of said plurality of wireless base stations that are recorded, addresses of each of terminal devices that are currently participating in the network and existing under a respective one of the wireless base stations;

a short packet route control table and a long packet route control table that indicate for each of the other wireless base stations that structure the network which wireless base station are long a first route for a short packet and along a second route for a long packet;

a route determination unit configured to identify a wireless base station to which the source terminal device or the destination terminal device currently belongs according to the location table, based on a source address of the source terminal device or a destination address of the destination terminal device included in a received packet, and to determine whether the packet is a short packet or a long packet to find a next hop based on either the short packet route control table or the long packet route control table, respectively, and find the next hop; and

a packet transmission unit configured to transmit the packet to the next hop according to the determination result.

4. The wireless base station of claim 3, wherein the packet transmission unit transmits a message packet reporting participation of a new terminal device when the new terminal device belongs to the wireless base station.

5. The wireless base station of claim 3, 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.

6. The wireless base station of claim 3, 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 either the short packet route control table or the long packet route control table.

7. The wireless base station according to claim 3, further comprising:

a cost estimation unit configured to send a route search packet to adjacent wireless base stations that configure the network so that the adjacent wireless base station add up route costs to gather information on the first route and the second route for the short packet route control table and the long packet route control table, respectively.

8. 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 includes:

a location table recording an address of each of said plurality wireless base stations that structure a network, and for each of said plurality of wireless base stations that are recorded, addresses of the terminal devices that are currently associated with a respective wireless base station,

a short packet route control table and a long packet route control table that indicates for each of the other wireless base stations that structure the network which wireless base stations are along a first route for a short packet and along a second route for a long packet,

a packet creating unit configured, if said one of the wireless base stations is a wireless base station that first received a packet from a terminal device, to add address information of a wireless base station, to which the source terminal device or the destination terminal device of the received packet currently belongs, to the received packet with reference to the location table,

a route determination unit configured, upon receiving a packet from another wireless base station, to determine a next hop wireless base station to which the received packet is to be forwarded, based upon the address information of the wireless base station to which the source terminal device or the destination terminal device currently belongs, the address information included in the packet, and based upon either the short packet route control table or the long packet route control table, respectively, by first determining whether the packet is a short packet or a long packet,

a packet transmission unit configured to transmit the packet to the next hop wireless base station determined by the route determination unit, and

a location table updating unit configured to exchange the information in the location table with the other wireless base stations and update the location table of this wireless base station.

9. The packet transmission system of claim 8,

wherein the packet transmission unit of a corresponding wireless base station is further configured to transmit a message packet reporting participation of a new terminal device when the new terminal device belongs to the corresponding wireless base station;

and

wherein the location table updating unit is further configured to update the location table when the message packet is received from another wireless base station.

10. The packet transmission system of claim 8,

wherein the packet creating unit is configured, if said one of the wireless base stations is a wireless base station that first receives a packet from a terminal device, to add ID information of a transmission route for this packet to the receive packet, and

wherein upon receiving a packet from another wireless base station, the route determination unit determines the next hop wireless base station from the ID information of the transmission route included in the received packet, with reference to the route control table.

11. The packet transmission system according to claim 8, wherein at least one of the wireless base stations includes:

a cost estimation unit configured to send a route search packet to adjacent wireless base stations that configure the network so that the adjacent wireless base station add up route costs to gather information on the first route and the second route for the short packet route control table and the long packet route control table, respectively.

12. A wireless base station used in a wireless packet transmission system, comprising:

a location table to record an address of each of said plurality wireless base stations that structure a network, and for each of said plurality of wireless base stations that are recorded, addresses of the terminal devices that are currently associated with a respective wireless base station,

a short packet route control table and a long packet route control table that indicate for each of the other wireless base stations that structure a network in the wireless packet transmission system which wireless base station are along a first route for a short packet and along a second route for a long packet,

a packet creating unit configured, if this wireless base station is one that first received a packet from a terminal device, to add address information of a wireless base station, to which the source terminal device or the destination terminal device of the received packet currently belongs, to the received packet with reference to the location table,

a route determination unit configured, upon receiving a packet from another wireless base station, to determine a next hop wireless base station to which the received packet is to be forwarded, based upon the address information of the wireless base station to which the source terminal device or the destination terminal device currently belongs, the address information included in the packet, and based upon either the short packet route control table or the long packet route control table, respectively, by first determining whether the packet is a short packet or a long packet,

a packet transmission unit configured to transmit the packet to the next hop wireless base station determined by the route determination unit, and

a location table updating unit configured to exchange the information in the location table with the other wireless base stations and update the location table of this wireless base station.

13. The wireless base station of claim 12,

wherein the packet transmission unit configured to transmit a message packet reporting participation of a new terminal device when the new terminal device belongs to this wireless base station;

and

wherein the location table updating unit configured to update the location table when the message packet is received from another wireless base station.

14. The wireless base station according to claim 12, further comprising:

a cost estimation unit configured to send a route search packet to adjacent wireless base stations that configure the network so that the adjacent wireless base station add up route costs to gather information on the first route and the second route for the short packet route control table and the long packet route control table, respectively.