PCS-to-mobile IP internetworking

• US 6,487,406 B1
• Filed: 04/10/2000
• Issued: 11/26/2002
• Est. Priority Date: 06/16/1999
• Status: Expired due to Term

• Current Assignee: CommWorks Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Telcordia Technologies Incorporated (Telefonaktiebolaget LM Ericsson)
• Inventors: Varma, Vijay K., Chang, Li-Fung
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US09/545,619
• Time in Patent Office: 960 Days
• Field of Search: 455/426, 455/445, 455/460, 455/432, 455/433, 455/436, 370/401, 370/338, 709/238, 709/239
• US Class Current: 455/422.1
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 8/02 Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/16 Gateway arrangements
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A method and system for providing seamless mobile IP connectivity between mobile stations (MS) connected to a PCS network via base stations (BS) connected to base station switching centers (BSCs). The BSCs are connected to a mobile station switching station (MSC) and are configured to direct voice traffic from the MS to the MSC. A gateway router (GR) is connected between the BSCs and the Internet and each BSC is configured as an IP data node. One or more subnets are defined, each of which includes at least one BSC. Each MS is assigned a permanent IP address and associated with a home subnet. When the system detects that the MS is connected to a BSC outside of its home subnet, it is assigned a care-of address to the MS to which IP data can be forwarded. IP data from the MS is routed through the GR. IP data directed to the MS is directed to the MS'"'"'s permanent IP address. If the MS is connected to a BSC outside of its home subnet, the data traffic is forwarded to the MS'"'"'s care-of address. A mobile station and base station controller for use in such a network is also presented.

Claims

1. A method for providing data communication to mobile stations (MS) connected to a first data network comprising a plurality of base stations (BS) communicating with the MSs and connected to a respective one of a plurality of base station switching centers (BSCs), the BSCs connected to a mobile station switching station (MSC) and configured to direct voice traffic from the MS to the MSC, the method comprising the steps of:

providing at least one gateway router (GR) connected between the BSCs and a second data network;

configuring each BSC as a node suitable for routing data traffic between a connected MS and the GR;

defining at least one subnet, each subnet including at least one BSC;

assigning a permanent address to an MS and associating the MS with a home subnet;

assigning a care-of address to the MS in response to the detection that the MS is connected to a BSC not in the MS'"'"'s home subnet;

directing data traffic from the MS to the GR; and

routing data traffic received from a remote site and directed to the MS'"'"'s permanent IP address, whereby, when the MS is connected to a BSC not in the MS'"'"'s home subnet, the received data traffic is forwarded to the MS'"'"'s care-of address.

2. The method of claim 1, wherein the first data network includes a PCS data network.

3. The method of claim 1, wherein:

the second data network includes the Internet;

the data traffic includes IP data traffic; and

the permanent address includes an IP address;

whereby the method provide seamless IP data connectivity between an MS and the Internet.

4. The method of claim 1, further comprising the step of:

maintaining in a home mobility agent associated with each subnet, the current location of each MS in the network having the respective subnet as its home subnet.

5. The method of claim 4, further comprising the step of:

providing a foreign mobility agent associated with each subnet configured to enable IP data communications with an MS connected to the respective subnet and having a different subnet as its home subnet.

6. The method of claim 5, wherein the home and foreign mobility agents are separate computer modules.

7. The method of claim 5, further comprising the steps of:

detecting when the MS has moved from a previous BS to a new BS; and

determining the relationship between the BSC connected to the previous BS and the BSC connected to the new BS.

8. The method of claim 7, further comprising the steps of:

storing an ID of the previous BS in the MS; and

periodically transmitting from each BS a system broadcast comprising the ID of the transmitting BS;

the detecting step comprising sending a notification to the BSC connected to the new BS when the BS ID stored in the MS is different from the BS ID in a received system broadcast, the notification indicating the MS'"'"'s permanent address, its home subnet, and, if valid, its care-of address.

9. The method of claim 8, wherein the determining step is performed in the BSC in response to a received notification from the MS.

10. The method of claim 7, further comprising the step of:

when the determining step indicates that the new BS and the previous BS are connected to a common BSC, updating a BS-MS association table in the common BSC to associate the MS with the new BS.

11. The method of claim 10, wherein the BS-MS association table is stored in the common BSC.

12. The method of claim 7, when the determining step indicates that the new BS and the previous BS are connected to different BSCs in the same subnet, further comprising the steps of:

(a) updating a BS-MS association table in the BSC of the new BS to associate the MS with the new BS, and

(b) updating address binding information in at least one of the home and foreign mobility agents of that same subnet to thereby associate the MS with the BSC of the new BS.

13. The method of claim 7, when the determining step indicates that the new BS and the previous BS are connected to different BSCs in different subnets, further comprising the steps of:

sending an advertisement message from the BSC of the new BS to the MS containing registration information, the care-of address, and attributes of the subnet containing the BSC of the new BS; and

;

sending a registration message from the MS to the home agent of the MS'"'"'s home subnet containing the MS'"'"'s permanent address and at least some of the information in the advertisement message;

updating the current location of the MS as maintained by the home agent of the MS'"'"'s home subnet in accordance with data in the registration message; and

sending a reply from the home agent of the MS'"'"'s home subnet to the MS indicating a successful registration.

14. The method of claim 13, wherein the attributes comprise an identification of the foreign agent for the subnet containing the BSC of the new BS.

15. The method of claim 13, further comprising the steps of:

in response to the receipt of a successful registration reply, sending a registration confirmation message from the MS to the BSC of the new BS; and

;

updating a BS-MS association table in the BSC of the new BS to associate the MS with the new BS.

16. The method of claim 1, wherein all BSCs in given subnet are connected to a common node;

the step of directing data traffic from the MS to the GR comprises the steps of;

determining if the data traffic is directed to a second MS present in the same subnet;

in response to a positive determination, directing the data traffic from the MS to the second MS without involving the GR;

otherwise directing the data traffic to the GR.

17. A system integrating a first network with a second network comprising:

a mobile switching station (MSC);

a plurality of base station switching centers (BSCs) connected to the MSC;

at least one base station (BS) connected to each BSC, each base station providing an access point to the network for at least one mobile station (MS), each MS having a permanent address and being associated with a home subnet comprising at least one BSC;

at least one gateway router (GR) connected to the second network;

each BSC connected to a particular GR and configured as a node suitable for routing data traffic between an MS and the GR;

each BSC further configured to;

(a) direct voice traffic from the MS to the MSC,

(b) directing data traffic from the MS to the GR;

(c) assign, with the aid of a foreign mobility agent associated with the subnet containing the BSC, a care-of address to the MS in response to the detection that the MS is connected to a BSC not in the MS'"'"'s home subnet;

(d) route, with the aid of a home mobility agent associated with the subnet containing the BSC and maintaining the current location of each MS in the network having the respective subnet as its home subnet, data traffic received from a remote site and directed to the MS'"'"'s permanent address, whereby, when the MS is connected to a BSC not in the MS'"'"'s home subnet, the received data traffic is forwarded to the MS'"'"'s care-of address.

18. The system of claim 17, wherein the first data network includes a PCS data network.

19. The system of claim 17, wherein:

the second data network includes an IP data network;

the data traffic includes IP data traffic; and

the permanent address includes an IP address.

20. The system of claim 19, wherein the second data network includes the Internet.

21. The system of claim 17, wherein each subnet comprises a single home mobility agent and a single foreign mobility agent, the home and foreign mobility agents being shared by all BSCs in a respective subnet.

22. A mobile station for use with an integrated PCS and IP network accessible through a plurality of base stations (BSs), each base station having an ID and connected to a base station switching center (BSC), each BSC belonging to a subnet comprising at least one BSC, the mobile station comprising:

a control system having a computer processor and a memory;

a radio link transceiver for communicating with base stations (BSs) in the network, each base station having an ID;

the control system configured to;

receive system broadcasts containing a BS ID from an accessed BS;

detect if the accessed BS is different from a previously accessed BS;

in response to the detection that a new BS has been accessed, sending a Data_Location_Update message to a base station switching center (BSC) connected to the new BS;

receive communications from the BSC;

in response to the receipt of an Agent_Advertisement from the BSC;

(a) extract subnet information from the Agent_Advertisement, the subnet information including attributes of the subnet containing the BSC; and

(b) send a Mobile_IP_Registration datagram to a mobility agent associated with a home subnet assigned to the mobile station including the received subnet information.

23. The mobile station of claim 22, wherein the control system is further configured to:

receive a Mobile_IP_Registration reply from the mobility agent; and

upon receipt of a valid reply, send a Location_Update_Confirm message to the BSC.

24. The mobile station of claim 22, wherein:

the mobile station is configured to receive a permanent IP address; and

the Data_Location_Update message includes the permanent IP address.

25. The mobile station of claim 22, wherein the control system is configured to initiate a PCS registration procedure in response to the detection that a new BS has been accessed when the new BS is in a different PCS network than the previously accessed BS.

26. A base station switching controller (BSC) for use in an integrated PCS and IP network accessible through a plurality of base stations (BSs), each base station having an ID and connected a respective BSC where each BSC belongs to a subnet comprising at least one BSC, the BSC comprising:

a control system having a computer processor and a memory;

a first data interface for communicating with at least one BS;

a second data interface for communicating with a mobility agent associated with the subnet to which the BSC belongs and for passing IP data communications between a mobile station connected to the BSC through a BS and a gateway router in communication with the BSC;

the control system configured to;

(a) receive a Data_Location_Update message from a mobile station (MS) in communication with the BSC through a first BS indicating that the MS has moved from a second BS to the first BS;

(b) determining if the subnet of the BSC is the same as a subnet for a second BSC of the second BS; and

(c) updating an MS-BS association table in the memory to associate the MS with the second BS if the subnets are the same.

27. The base station switching controller of claim 26, wherein the control system is further configured to send an address resolution protocol (ARP) reply to the mobility agent associated with the subnet of the BSC if the second BSC and the BSC are different units.

28. The base station switching controller of claim 27, wherein the control system is further configured to:

(d) send an Agent_Advertisement to the MS following receipt of the Data_Location_Update message and a determination that the subnet of the BSC and the subnet for the second BSC are different;

(e) receive a Location_Update_Confirm message from the MS; and

(f) send an ARP reply to the mobility agent associated with the subnet of the BSC.