HK1078193A - Hybrid mobile switching center for combined gsm/is-41 communication - Google Patents

Description

Combined GSM/IS-41 communication composite mobile switching center

(Cross-reference to related applications)

This application claims priority to U.S. provisional patent application U.S. No.60/340,448, filed on 12, 14, 2001.

Technical Field

The present invention relates generally to wireless communication systems, and more particularly to systems that use a single CDMA radio access network with both a CDMA core network and a GSM core network.

Background

Code Division Multiple Access (CDMA) is a digital wireless technology that inherently has a relatively large bandwidth capacity, and in particular, inherently allows more telephone calls to be serviced per unit frequency band than other wireless communication technologies. Moreover, the spread spectrum principle of CDMA itself provides secure communications. U.S. patent No. 4,901,307, which is hereby incorporated by reference, gives details of a CDMA system that can be used to transmit both voice calls and non-voice computer data.

Despite the advantages of CDMA, there are still other wireless systems that apply other principles. For example, GSM is used in most parts of the world, and a time division multiple access scheme is used.

Regardless of the CDMA principles or other wireless principles employed, a wireless communication system can be considered to have two major components, specifically a wireless Radio Access Network (RAN), and a core infrastructure, such as the Public Switched Telephone Network (PSTN), the internet (particularly but not exclusively for data calls), etc., that communicates with the RAN and various external systems. The core infrastructure associated with various wireless technologies may be expensive, both in terms of hardware and in terms of developing communication protocols to support specific, typical system-specific call exchanges, user identity and service authentication, call monitoring, and accounting. Thus, the communication protocols of one wireless system (such as the GSM protocols in the GSM scenario and CDMA2000-1x, IS-41 protocols in the CDMA scenario) may not be compatible with the communication protocols of another system without a costly prohibitive alternative in the core infrastructure of one or the other system.

In light of the above disclosure, the present invention recognizes that it would be desirable to allow a CDMA-based RAN, which has its service advantages, to be used not only for CDMA core infrastructure, but also for GSM-based core infrastructure, since GSM is present in most parts of the world. The present invention further recognizes that, in view of the above discussion, the rationality is greatly reduced without eliminating the need for modifications to the various communication protocols of the GSM core infrastructure.

Furthermore, the present invention recognizes that a dual-mode mobile station that forms advantageous interfaces with a CDMA RAN may be provided that uses the GSM core infrastructure in, for example, europe, and the CDMA infrastructure in, for example, the united states. Unfortunately, such a mobile station has until now required the subscriber identity and telephone number of the GSM system and the subscriber identity and telephone number of an alternative CDMA system. This adds both complexity and cost from a user standpoint. The present invention recognizes that it would be desirable to allow dual mode CDMA mobile stations to be used without requiring the identity of the user of both the CDMA core and the GSM core.

Disclosure of Invention

A Mobile Switching Center (MSC) IS configured to support wireless communications between a Code Division Multiple Access (CDMA) Radio Access Network (RAN) and both a GSM core infrastructure and an IS-41 core infrastructure. The mobile switching center includes first circuitry for communicating with a CDMA radio access network and for communicating with an IS-41 core infrastructure using IS-41 protocols. Furthermore, the mobile switching center includes second circuitry for communicating with the CDMA radio access network and for communicating with the GSM core infrastructure using GSM protocols.

In a preferred embodiment, the first or second circuit is selected based on a message from a Mobile Station (MS), such as a location message. The location message may include an International Mobile Subscriber Identifier (IMSI) that is used by the mobile switching center to determine which core infrastructure subscriber identity the mobile station has.

In another aspect, a state machine Mobile Switching Center (MSC) IS configured to support wireless communications between a Code Division Multiple Access (CDMA) Radio Access Network (RAN) and both a GSM core infrastructure and an IS-41 core infrastructure. The mobile switching center includes a state machine that IS selectively configurable to communicate with the IS-41 core infrastructure using the IS-41 protocol or with the GSM core infrastructure using the GSM protocol based on an identifier received from a communicating mobile station.

In another aspect, a communication system includes: a CDMA radio access network; a GSM core infrastructure; and a CDMA core infrastructure. A mobile switching center interconnects the CDMA radio access network with both of the above infrastructures.

In yet another aspect, a method for communicating with a first wireless Mobile Station (MS) having a GSM core infrastructure subscriber identity and with a second wireless mobile station having a CDMA core infrastructure subscriber identity without requiring any of the mobile stations to have more than a single subscriber identity includes receiving an identifier from a mobile station at a mobile switching center. Based on the identifier, the method determines which core infrastructure subscriber identity the mobile station has. The method authenticates the mobile station with information from a core infrastructure of the mobile station having a subscriber identity via the mobile switching center. The accounting data is collected using the core infrastructure of the mobile station having the user identity.

In another aspect, a mobile switching center of a wireless communication system includes: means for receiving an identifier from a mobile station; and means for employing the identifier to determine whether the mobile station has a GSM core infrastructure user identity or a CDMA core infrastructure user identity. Provided are means for communicating with both of the above core infrastructures.

In another aspect, a wireless Mobile Station (MS) includes a memory device that stores an identifier, such as an international mobile subscriber identifier. A radio associated with the mobile station communicates the identifier to a CDMA Radio Access Network (RAN), the mobile station having only a GSM core infrastructure subscriber identity.

The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which:

drawings

FIG. 1 is a block diagram of the present system for facilitating roaming between a GSM core infrastructure and a CDMA core infrastructure;

FIG. 2 is a flow chart of the logic of the present invention;

FIG. 3 IS a schematic representation of a mobile switching center of the present invention having an IS-41 circuit and a separate GSM circuit; and

fig. 4 schematically shows a second inventive mobile switching center having a single state machine that may selectively assume either an IS-41 configuration or a GSM configuration.

Detailed Description

Referring initially to fig. 1, there IS shown a system, generally designated 10, for facilitating communications, including voice communications and computer data communications, between a Code Division Multiple Access (CDMA) Radio Access Network (RAN)12 and both a GSM core infrastructure 14 and an IS-41 core infrastructure 15. While the GSM core infrastructure 14 and IS-41 core infrastructure 15 may communicate with an Internet Protocol (IP) network 16, such as the Public Switched Telephone Network (PSTN) and/or the Internet, for example. The GSM core infrastructure 14 may include or may access a GSM authentication center (AUC)14a and a GSM Home Location Register (HLR)14b in accordance with GSM principles known in the art to authenticate each subscriber mobile station and collect accounting and accounting information as required by the particular GSM core infrastructure 14. Likewise, the IS-41 core infrastructure 15 may include or may access an IS-41 authentication center (AUC)15a and an IS-41 Home Location Register (HLR)15b, in accordance with IS-41 principles known in the art, to authenticate each subscriber mobile station and collect accounting and accounting information as required by the particular IS-41 core infrastructure 15.

The CDMA radio access network comprises base stations and base station controllers according to CDMA principles known in the art. The preferred CDMA radio access network 12 shown in fig. 1 employs CDMA2000, and in particular, CDMA 20001 x, CDMA 20003 x, or CDMA2000 High Data Rate (HDR) principles.

As shown in fig. 1, the CDMA radio access network 12 supports wireless communications with at least one dual-mode CDMA Mobile Station (MS)18 supporting GSM and at least one single-mode or dual-mode CDMA mobile station 20. The GSM-enabled mobile station 18 may be engaged and disengaged with a Subscriber Identity Module (SIM)22 in accordance with GSM principles known in the art. In the exemplary embodiment shown in fig. 1, the GSM enabled mobile station 18 has the subscriber identity of the GSM core infrastructure 14, but need not have the IS-41 core infrastructure 15 subscriber identity. In contrast, the IS-41 mobile station 20 has the subscriber identity of the IS-41 core infrastructure 15, but need not have the subscriber identity of the GSM core infrastructure 14.

In a non-limiting embodiment, one or both of the mobile stations 18, 20 are mobile telephones made by kyoto, samsung, or other manufacturers that employ Code Division Multiple Access (CDMA) principles and CDMA over the air (ota) communication air interfaces. The present invention is applicable to other mobile stations such as laptop computers, wireless handsets or telephones, data transceivers, or paging and location receivers. Each mobile station may be hand-held or mobile while on-board a vehicle (including cars, trucks, boats, planes, trains), as desired. Although wireless communication devices are generally considered to be mobile, it should be understood that the present invention may be applicable to "fixed" units in some implementations. Moreover, the present invention is applicable to data modules or modems used to transfer voice and/or data information, including digitized video information, and may communicate with other devices using various wired or wireless links. In addition, commands may be employed to cause the modems or modules to transfer information in a predetermined coordinated or associated manner over the multiple communication channels. Wireless communication devices are also sometimes referred to as user terminals, mobile stations, mobile units, subscriber units, mobile radio stations or radiotelephones, wireless units, or simply as "users" and "mobiles" in some communication systems.

Interconnecting the various core infrastructures 14, 15 with the CDMA radio access network 12 is a composite Mobile Switching Center (MSC) 24. As mentioned below, the mobile switching center 24 IS a composite mobile switching center that communicates with the GSM core infrastructure 14 using GSM principles and protocols and with the IS-41 core infrastructure 15 using IS-41 principles and protocols. Referring briefly to fig. 3, the mobile switching center 24 may be implemented by GSM Mobile Switching Center (MSC) circuitry that communicates with the GSM core infrastructure 14 when the International Mobile Subscriber Identifier (IMSI) message described below indicates that the mobile station has a GSM core infrastructure 14 subscriber identity, and IS-41 circuitry that communicates with the IS-41 core infrastructure 15 when the International Mobile Subscriber Identifier (IMSI) message described below indicates that the mobile station has an IS-41 core infrastructure 15 subscriber identity. In another non-limiting embodiment shown in fig. 4, the msc 24 IS a single state machine, essentially a superset of a GSM msc and IS-41 msc, which superset selectively assumes either a GSM state or an IS-41 state depending on the particular ms being served, as described in more detail below.

The logic of the system 10 and in particular the mobile switching center 24 can be understood with reference to fig. 2. Beginning at block 26, one of the mobile stations 18, 21 sends a message to the mobile switching center 24 using the CDMA radio access network 12 that includes an identification of the mobile station, such as an International Mobile Subscriber Identifier (IMSI). This message sent by the mobile station may be, for example, a location update message.

Proceeding to block 28, the mobile switching center 24 determines from the International Mobile Subscriber Identifier (IMSI) whether the communicating mobile station has a subscriber identity of the GSM core infrastructure 14 or the IS-41 core infrastructure 15. One way to make this determination is to access a database associated with the mobile switching center that correlates each international mobile subscriber identifier with each home location register (and thus each serving core). Another approach IS to communicate the international mobile subscriber identifier to both the GSM core infrastructure 14 and the IS-41 core infrastructure 15, with the serving core to which the communicating mobile station belongs replying to the mobile switching center 24.

In any case, if the GSM-enabled mobile station 18 is the mobile station in the communication, the preferred mobile switching center 24 assumes its GSM state at block 30, and authenticates the mobile station 18 by accessing the GSM core infrastructure 14 and its associated GSM authentication center 14a and GSM home location register 14b using GSM protocols and authentication principles known in the art. If the IS-41 mobile station 20 IS the mobile station in the communication, the preferred mobile switching center 24 assumes its IS-41 state, and authenticates the mobile station 20 using IS-41 protocols and authentication principles known in the art by accessing the IS-41 core infrastructure 15 and its associated IS-41 authentication center 15a and IS-41 home location register 15 b. Thus, it can now be appreciated that a GSM-enabled mobile station 18 can authenticate itself by the GSM core infrastructure 14 through the mobile switching center 24, even though the mobile station 18 is in an area otherwise served by the CDMA core infrastructure 15. In other words, the GSM-capable mobile station 18 may roam from a GSM service area to an IS-41 service area, even though the subscriber identity of the IS-41 core IS not present.

When the GSM enabled mobile station 18 has been authenticated, the GSM core infrastructure 14 collects accounting/billing data during the call that is connected through the mobile switching center 24 at block 32 and provides service at block 34. The subscriber is billed at block 36 using the GSM core infrastructure 14. Conversely, when an IS-41 capable mobile station 20 has been authenticated, the IS-41 core infrastructure 15 collects accounting/billing data during a call that IS connected through the mobile switching center 24 and IS serviced at block 34. The subscriber IS billed at block 36 using the IS-41 core infrastructure 15.

While the particular combined GSM/IS-41 communications composite mobile switching center as herein illustrated and described in detail IS fully capable of attaining the above-described objects of the invention, it IS to be understood that it IS the presently preferred embodiment of the present invention and IS thus an exemplification of the subject matter which IS regarded as being within the broad scope of the present invention, and that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art. It is also to be understood that the scope of the invention is thus limited to the appended claims, and not by others, in which reference to a certain element in the singular is intended to mean "one or more" unless specifically so stated. All structural and functional equivalents to the elements of the above-described preferred embodiment that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No element in the claims is intended to be construed as limited by the 35 u.s.c. § 112, 6, unless the element is explicitly referred to by the phrase "means for … …," or by the term "step" rather than "action" in the method claims.

Claims (27)

1. A Mobile Switching Center (MSC) configured to support wireless communications between a Code Division Multiple Access (CDMA) Radio Access Network (RAN) and both a GSM core infrastructure and an IS-41 core infrastructure, comprising:

first circuitry in communication with a CDMA radio access network, the first circuitry employing an IS-41 protocol to communicate with an IS-41 core infrastructure; and

second circuitry in communication with the CDMA radio access network, the second circuitry to communicate with the GSM core infrastructure using GSM protocols.

2. A mobile switching center according to claim 1, characterized in that the first or second circuit is selected on the basis of at least one message from a Mobile Station (MS).

3. The mobile switching center of claim 2, wherein the message is a location message.

4. The mobile switching center of claim 3, wherein the location message includes an International Mobile Subscriber Identifier (IMSI).

5. The MSC of claim 4 wherein the MSC uses the IMSI to determine which core infrastructure subscriber identity the MS has.

6. A state machine Mobile Switching Center (MSC) configured to support wireless communications between a Code Division Multiple Access (CDMA) Radio Access Network (RAN) and both a GSM core infrastructure and an IS-41 core infrastructure, comprising:

a state machine selectively configurable to communicate with the IS-41 core infrastructure using the IS-41 protocol or with the GSM core infrastructure using the GSM protocol based on the at least one identifier received from the at least one mobile station.

7. The mobile switching center of claim 6, wherein the identifier is included in at least one message from the mobile station.

8. The mobile switching center of claim 7, wherein the message is a location message.

9. The mobile switching center of claim 8, wherein the location message includes an International Mobile Subscriber Identifier (IMSI).

10. The mobile switching center of claim 9 wherein the mobile switching center uses the international mobile subscriber identifier to determine which core infrastructure subscriber identity the mobile station has, whereby the mobile switching center configures itself.

11. A communication system, comprising:

a CDMA radio access network;

a GSM core infrastructure;

a CDMA core infrastructure; and

a mobile switching center interconnecting the CDMA radio access network and the two infrastructures.

12. The system of claim 11, wherein the mobile switching center comprises:

a first circuit in communication with the CDMA radio access network and employing IS-41 protocol to communicate with IS-41 core infrastructure; and

a second circuit in communication with the CDMA radio access network and in communication with the GSM core infrastructure using GSM protocols.

13. A system as claimed in claim 12, characterized in that the first or second circuit is selected on the basis of at least one message from a Mobile Station (MS).

14. The system of claim 13, wherein the message is a location message.

15. The system of claim 14 wherein the location message includes an International Mobile Subscriber Identifier (IMSI).

16. The system of claim 15 wherein the mobile switching center uses the international mobile subscriber identifier to determine which core infrastructure subscriber identity the mobile station has.

17. The system of claim 11, wherein the mobile switching center IS a state machine selectively configurable to communicate with the IS-41 core infrastructure using the IS-41 protocol and to communicate with the GSM core infrastructure using the GSM protocol based on the at least one identifier received from the at least one mobile station.

18. A method for communicating with a first wireless Mobile Station (MS) having a GSM core infrastructure subscriber identity and with a second wireless mobile station having a CDMA core infrastructure subscriber identity without requiring either of the mobile stations to have more than a single subscriber identity, comprising the steps of:

receiving at a mobile switching center at least one identifier from at least one mobile station;

determining which core infrastructure subscriber identity the mobile station has based on the identifier;

authenticating, by the mobile switching center, the mobile station using information from a core infrastructure of the mobile station having a user identity; and

the accounting data is collected using the core infrastructure of the mobile station having the user identity.

19. The method of claim 18, wherein the act of receiving is performed using a CDMA radio access network.

20. The method of claim 18, wherein the identifier is an International Mobile Subscriber Identifier (IMSI).

21. A method as defined in claim 18, further comprising billing a mobile station user with accounting data collected by the associated core infrastructure.

22. The method of claim 18, comprising: according to the judging action:

the GSM protocol IS employed in at least part of the authentication action when the mobile station has a GSM core infrastructure user identity and the IS-41 protocol IS employed in at least part of the authentication action when the mobile station has a CDMA core infrastructure user identity.

23. A mobile switching center of a wireless communication system, comprising:

means for receiving an identifier from a mobile station;

means for employing the identifier to determine whether the mobile station has a GSM core infrastructure user identity or a CDMA core infrastructure user identity; and

means for communicating with both of the above core infrastructures.

24. A wireless Mobile Station (MS), comprising:

at least one storage device including an identifier;

communicating the identifier to at least one radio of a CDMA Radio Access Network (RAN); and

only one GSM core infrastructure subscriber identity.

25. The mobile station of claim 24 wherein the mobile station communicates with a Mobile Switching Center (MSC) using the CDMA radio access network and authenticates to a GSM core infrastructure when the mobile station is located in an area served by a CDMA core infrastructure.

26. The mobile station of claim 24, wherein the identifier is an International Mobile Subscriber Identifier (IMSI).

27. The mobile station of claim 26, wherein the mobile station sends the international mobile subscriber identity as part of a location update message.