Mobile ip packet communication system

• US 20040076158A1
• Filed: 09/02/2003
• Published: 04/22/2004
• Est. Priority Date: 03/01/2001
• Status: Active Grant

• Current Assignee: Akira Okubo, Hiroshi Matsuyama
• Original Assignee: Akira Okubo, Hiroshi Matsuyama
• Inventors: Okubo, Akira, Matsuyama, Hiroshi
• Granted Patent: US 7,586,913 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• 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 45/16 Multipoint routing
• 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 76/20 Manipulation of established connections
• CPC Class Codes: H04W 92/02 Inter-networking arrangements
• CPC Class Codes: H04W 92/24 between backbone network devices

Abstract

In a mobile IP packet communication system including mobile terminals (8), radio base stations (6), base station control apparatuses (5), subscriber packet exchange apparatuses (8), a gateway and packet data exchange apparatus (1), when receiving a packet sent thereto from a mobile terminal that is a sending source, a subscriber packet exchange apparatus encapsulates the packet with a multicast address without acquiring information on a routing area (13) in which another mobile terminal that is a destination is currently located from a home location register (2), and routes the packet to another subscriber packet exchange apparatus that manages the routing area in which the destination mobile terminal is currently located. As a result, the moving object IP packet communication system can carry out the transmission of data packets between the source and destination mobile terminals while reducing the transfer delay.

Claims

1. A mobile IP packet communication system including

mobile terminals;

radio base stations each for communicating with said mobile terminals;

base station control apparatuses each for managing a plurality of said radio base stations and for controlling radio channels;

subscriber packet exchange apparatuses each for managing a routing area having a plurality of said radio base stations and one said base station control apparatus, and each for controlling transfer of packets to one said mobile terminal;

a gateway and packet data exchange apparatus having a gateway function of serving as a gateway between each of said subscriber packet exchange apparatuses and a data packet network disposed outside said mobile IP packet communication system;

a home location register for managing information on routing areas in which said mobile terminals are currently located, respectively; and

visitor location registers each for managing information on zones within a corresponding routing area, in which said mobile terminals can be currently located,

when transferring a packet destined for one said subscriber packet exchange apparatus that manages a routing area in which one said mobile terminal that is a destination is currently located, said mobile IP packet communication system transmitting the packet either between another said subscriber packet exchange apparatus that manages a routing area in which one said mobile terminal that is a sending source is currently located and said gateway and packet data exchange apparatus, or between said other subscriber packet exchange apparatus and said subscriber packet exchange apparatus after encapsulating the packet by adding address information destined for said subscriber packet exchange apparatus that is the destination to the packet,

characterized in that

when transferring a packet sent thereto from said source mobile terminal to said subscriber packet exchange apparatus to which said destination mobile terminal belongs, said other subscriber packet exchange apparatus encapsulates the packet with a multicast address without acquiring location information on a location of said destination mobile terminal from said home location register or a corresponding visitor location register.

2. The mobile IP packet communication system according to claim 1, characterized in that when receiving the packet encapsulated with the multicast address and destined for said destination mobile terminal, said subscriber packet exchange apparatus to which said destination mobile terminal belongs decapsulates the received packet and transfers the decapsulated packet to said destination mobile terminal and transmits a response message indicating that said destination mobile terminal is currently located in the routing area managed thereby to said other subscriber packet exchange apparatus that is the sending source.

3. The mobile IP packet communication system according to claim 2, characterized in that said subscriber packet exchange apparatus which has received the packet that is encapsulated with the multicast address and that is sent to said destination mobile terminal and to which said destination mobile terminal belongs decapsulates the received packet and transfers the decapsulated packet to said destination mobile terminal, and starts a timer when transmitting the response message and repeatedly transmits the response message to said other subscriber packet exchange apparatus that is the sending source until said timer expires.

4. The mobile IP packet communication system according to claim 2, characterized in that after encapsulating the packet that said other subscriber packet exchange apparatus has received from said source mobile terminal and transferring the packet to said subscriber packet exchange apparatus to which said destination mobile terminal belongs, said other subscriber packet exchange apparatus provides a status notification region for notification of communication status in a header region of each following packet to be transmitted in advance, when receiving the response message from said subscriber packet exchange apparatus to which said destination mobile terminal belongs, notifies said subscriber packet exchange apparatus that is the destination that said other subscriber packet exchange apparatus has already received the response message by using the status notification region of each following packet to be transmitted.

5. The mobile IP packet communication system according to claim 1, characterized in that in case where said destination mobile terminal transmits a packet to said source mobile terminal when said subscriber packet exchange apparatus that is a destination transmits a response message indicating that said destination mobile terminal is currently located in the routing area managed thereby to said other subscriber packet data exchange that is a sending source, said subscriber packet exchange apparatus transfers the packet from said destination mobile terminal to said source mobile terminal by superimposing information corresponding to the response message on the packet.

6. The mobile IP packet communication system according to claim 1, characterized in that when transferring the packet received from said source mobile terminal to either said subscriber packet exchange apparatus to which said destination mobile terminal belongs or an external packet data network to which a fixed terminal that is a destination belongs, said other subscriber packet exchange apparatus determines whether the packet is destined for either said destination mobile terminal or said fixed terminal, encapsulates the packet with the multicast address when the packet is destined for said destination mobile terminal, and transfers the packet to said subscriber packet exchange apparatus to which said destination mobile terminal belongs.

7. The mobile IP packet communication system according to claim 1, characterized in that when transferring the packet received from said source mobile terminal to either said subscriber packet exchange apparatus to which said destination mobile terminal belongs or an external packet data network to which a fixed terminal that is a destination belongs, said other subscriber packet exchange apparatus encapsulates the packet with the multicast address without determining whether the packet is destined for either said destination mobile terminal or said fixed terminal, and, when receiving the packet encapsulated with the multicast address and destined for said fixed terminal that is a destination, said gateway and packet exchange apparatus transfers the received packet to said fixed terminal that is a destination after decapsulating the packet and transmits a response message indicating that said fixed terminal is connected with a network managed thereby to said other subscriber packet exchange apparatus that is a sending source.

8. The mobile IP packet communication system according to claim 1, characterized in that when transferring the packet received from said source mobile terminal to either said subscriber packet exchange apparatus to which said destination mobile terminal belongs or an external packet data network to which a fixed terminal that is a destination belongs, said other subscriber packet exchange apparatus determines whether the packet is destined for either said destination mobile terminal or said fixed terminal, and encapsulates the packet with the multicast address and transfers the packet without acquiring the location information on the location of said destination mobile terminal from either said home location register or said corresponding visitor location register when determining that the packet is destined for said destination mobile terminal and that the packet is to be transmitted through real-time packet communications.

9. The mobile IP packet communication system according to claim 7, characterized in that when receiving the packet encapsulated with the multicast address and destined for said fixed terminal that is a destination, said gateway and packet exchange apparatus decapsulates the received packet and transfers the decapsulated packet to said fixed terminal, and starts a timer when transmitting the response message and repeatedly transmits the response message to said other subscriber packet exchange apparatus that is a sending source until said timer expires, or repeatedly transmits the response message to said other subscriber packet exchange apparatus that is a sending source until being notified that said other subscriber packet exchange apparatus has already received the response message through a status notification region located in a header region of each following packet transmitted thereto.

10. The mobile IP packet communication system according to claim 1, characterized in that in case where said fixed terminal that is a destination transmits a packet to said source mobile terminal when said gateway and packet exchange apparatus transmits a response message indicating that said fixed terminal is connected with a network managed thereby to said other subscriber packet exchange that is a sending source, said gateway and packet exchange apparatus transfers the packet from said destination fixed terminal to said source mobile terminal by superimposing the response message on the packet.

11. The mobile IP packet communication system according to claim 2, characterized in that either said subscriber packet exchange apparatus or said gateway and packet exchange apparatus, which has received the packet encapsulated with the multicast address and destined for destination terminal equipment, decapsulates the received packet and transfers the decapsulated packet to said destination terminal equipment, and transmits an RSVP reserve message, as the response message, to said other subscriber packet exchange apparatus that is a sending source so as to reserve a band.

12. The mobile IP packet communication system according to claim 2, characterized in that either said subscriber packet exchange apparatus or said gateway and packet exchange apparatus, which has received the packet encapsulated with the multicast address and destined for destination terminal equipment, decapsulates the received packet and transfers the decapsulated packet to said destination terminal equipment, and transmits an MPLS LDP message, as the response message, to said other subscriber packet exchange apparatus that is a sending source so as to set a virtual path.

13. A mobile IP packet communication system including a plurality of exchange stations each having a predetermined routing area, characterized in that each said exchange station includes:

a packet exchange means for receiving a data packet to which a destination address is added, for encapsulating said data packet into a data frame by using a predetermined multicast address, and for transmitting said data frame to a plurality of exchange stations corresponding to said multicast address; and

a visitor location register for managing information on mobile terminals which are currently located in the routing area own by said exchange station itself,

when receiving a data frame from another exchange station, said packet exchange means retrieving a data packet from said data frame, determining whether or not a destination mobile terminal specified by a destination address added to said retrieved data packet is currently located in the routing area own by said exchange station itself based on the information on mobile terminals which are currently located in the routing area, and, when determining that the destination mobile terminal is currently located in the routing area, transferring said data packet to the destination mobile terminal.