WO2000040053A1

WO2000040053A1 - Configurable communication system having ip-based capabilities

Info

Publication number: WO2000040053A1
Application number: PCT/US1999/030569
Authority: WO
Inventors: Subhankar Ray; Eric Valentine
Original assignee: Ericsson Inc.
Priority date: 1998-12-23
Filing date: 1999-12-21
Publication date: 2000-07-06
Also published as: EP1142422A1; AU2376800A; JP2002534874A; CA2356839A1

Abstract

A system and method for a subscriber of a mobile communication system to selectively identify a preference for cells having a capability to access an Internet Protocol (IP) application is disclosed. The identified cell capability preference is utilized by the system in assigning a cell to the subscriber. The system broadcasts IP based capabilities of its cells to the subscriber to facilitate the identification of the cell capability preference. The terminal of the subscriber transmits the terminal's IP based capabilities to the system to facilitate the cell assignment process.

Description

CONFIGURABLE COMMUNICATION SYSTEM HAVING IP-BASED CAPABILITIES

BACKGROUND OF THE INVENTION Technical Field of the Invention

The present invention relates generally to communication systems, and, more particularly, to a system and method for configuring the method of communication in a wireless communication system having Internet Protocol (IP) based capabilities.

Background and Objects of the Invention

Mobile wireless communication is becoming increasingly important for providing safety, convenience, improved productivity, and simple conversational pleasure. One prominent mobile wireless communication option is cellular communication. Cellular phones, for instance, can be found in cars, briefcases, purses and even pockets. In a mobile cellular telecommunications system, a mobile station normally communicates with the base station corresponding to the cell area in which the mobile station is located. There are circumstances, however, under which communication with the mobile station changes from one cell within the telecommunications network to another. A first situation is a handover operation in which the a mobile station roams into another cell while in a telephone call or other transaction. In order to choose a best cell for use by the roaming mobile station, signal strength measurements of cell signal transmissions are performed by the roaming mobile station. During the handover operation, various nodes in the network negotiate a cell change with the mobile station depending upon the nature of the handover. A second situation in which communication with a mobile station or terminal changes from one cell to another is a part of the Idle Mode procedures of the terminal/mobile station. This process, by which a terminal chooses which cell to utilize, is referred to as "camping on" a cell. The process includes location updating so that the serving mobile switching center (MS C) and corresponding visitor location register (NLR) maintain the approximate location ofthe terminal. The "camping on" process may, for example, occur when aterminal is powered up . The camping process may also occur when a terminal is not engaged in a telephone call but is moving around and monitoring the transmission quality ofthe different cells. In the event the terminal changes location areas while monitoring the quality ofthe cell transmissions, the terminal will perform a location update.

For cellular phone system providers to offer cellular phone users new services, cellular wireless networks must be upgraded. To this end, there exist and/or are planned wireless telecommunication networks which are capable of providing both standard GSM services and IP based services and/or applications. One advantage provided by such networks is that they are backwards compatible. In other words, the network provides both GSM services and IP applications, such as VoIP, to terminals which are capable of accessing IP based applications while at the same time maintaining conventional GSM wireless communication services for terminals which cannot utilize IP applications, such as due to limitations ofthe terminal itself.

One IP based application which is accessible by cellular telephone users is voice over IP (VoIP). The VoIP application provides quality voice communications over the packetized Internet. NoIP, over the current Internet, for example, can provide acceptable voice communications at a greatly reduced cost to the user, when compared to traditional mobile telephone tolls.

Although capable of providing telecommunication services to many subscribers, the above-described wireless network is not without its shortcomings. For instance, if a caller wishes to make a call in a wireless network having a VoIP application, a circuit switched call is transmitted from the corresponding Base Station System to the Mobile Switching Center (MSC), which is then sent along a trunk from the MSC to a gateway connected to an Internet Service Provider (ISP) . The gateway converts the call from a circuit switched voice call to a packet switched call for transmission on the Internet. Although this method of utilizing the Internet realizes reduced call tariffs, the NoIP call nonetheless utilizes circuit switch transmission resources in handling the call . Accordingly, there is a need for placing the point at which access is made to the Internet closer to the terminal and/or mobile station within the mobile communications network.

One approach is to place an interface for accessing the Internet within the Base Station Controllers (BSC) so that the switching circuitry ofthe network is substantially bypassed when an IP based application is provided to a mobile station user. In a communications network utilizing this approach, some ofthe cells in the network may be capable of providing IP based applications and/or communications, such as NoIP, in addition to conventional GSM based communication. A call placed by a terminal and/or mobile station served by these cells, for example, is capable of being transported over/through the Internet so as to incur a relatively inexpensive toll. Because not every BSC in the mobile network will typically possess the capability to provide IP based services and/or applications to mobile stations served thereby, there exists a need for ensuring that terminals requesting an IP based service are satisfactorily and cost effectively served.

It is an object ofthe present invention to provide a communications system in which the cell assignment to a terminal is dependent upon user preference.

It is another object ofthe present invention to provide such a communication system having enhanced communication of both network and terminal information between the network and a terminal therein.

SUMMARY OF THE INVENTION

The present invention overcomes shortcomings in existing communication systems and satisfies a significant need for a communication system having improved methods for accessing the system's IP based capabilities.

According to the present invention, there is provided a mobile communications network, such as, for example, a Public Land Mobile Network (PLMN), divided into a number of cells which communicate with at least one MSC via a number ofbase stations. At least one base station is capable of accessing an IP based application, such as VoIP by including a transcoder to convert a voice call transmitted by a terminal into a packet switched call for transport over the Internet. The cells associated with each base station transmit their service capabilities, including its IP-based capabilities, so that a terminal receiving the transmission is aware ofthe service capabilities of its present cell and neighboring cells. Conversely, each terminal in the mobile communications network transmits its own capabilities, such as being IP capable, to the network. In this way, both the network and each terminal can be apprised of each other's capabilities so that decisions pertaining to providing service-related activities, such as transporting a telephone call, are effectively carried out.

The present invention further includes each terminal possessing an interface and necessary circuitry to facilitate the user in selecting a cell preference from among cells which only support GSM-related services and cells which support both GSM-related services and

IP based applications. For example, the interface may allow the user to prefer cells which support NoIP for transporting telephone calls placed by the user's mobile station over the Internet. The system selects a cell for providing a service to the terminal, such as transporting a telephone call placed thereby, based in part upon the service-related capabilities of cells in the immediate area of the terminal and upon the selected cell preference. As a result, the present communications system suitably matches its available services to the user's service preferences.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding ofthe present invention may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings wherein:

Figure 1 is a block diagram of a telecommunications system according to the present invention; Figure 2 is a block diagram of a terminal according to the present invention;

Figure 3 is a flow chart illustrating a handover operation in association with the present invention;

Figure 4 is a flow chart illustrating a cell reassignment operation in association with the present invention; and Figure 5 is a flow chart illustrating a location update operation in association with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENTS

The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which a preferred embodiment ofthe invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete, and will fully convey the scope ofthe invention to those skilled in the art.

Referring to Figures 1 and 2, there is shown a communications system 1 including mobile communications network 2 and Internet and/or IP network 3. Mobile communications network 2 may preferably include a plurality of interconnected MSCs 4, each of which communicates with one or more base station controllers (BSC) 5. Each BSC

5 communicates with at least one base transceiver station (BTS) 6. A single BTS 6 serves one or more cells in mobile communications network 2. The operation of mobile communications network 2 and in particular the interrelationship between MSCs 4, BSCs 5 and BTSs 6 in providing mobile cellular services are known in the art and will not be described herein for reasons of simplicity.

One or more BSCs 5 of mobile communications network 2 may be capable of accessing IP network 3 in order to provide one or more IP applications to subscribers of the mobile communications network 2. A BSC 5 may, for example, have access to IP network 3 using one or more Internet Service Providers (ISP) 7. One IP application which a B SC 5 preferably accesses and is capable of providing to subscribers of mobile communications network 2 is VoIP, which provides acceptable voice communications at a greatly reduced subscriber cost, as explained above. Accordingly, the BSCs 5 which are capable of providing NoIP to subscribers ofthe mobile communications network 2 include a transcoder unit 8 or other device which converts a circuit switched (GSM) voice call to a packet switched call for transport over the Internet. By including transcoder unit 8 within aBSC 5, aVoIP telephone call placed by a terminal 9, such as a mobile station, bypasses the switching circuitry (MSCs 4) of mobile communications network 2. It is understood that a cell may be capable of accessing a number of IP based applications in addition to VoIP through its corresponding B SC 5. For instance, a cell in mobile communications network 2 may be capable of accessing an H.323 based multimedia application.

The present invention allows subscribers of mobile communications network 2 to more effectively access communication services provided by mobile communications network 2 and IP network 3. It is understood that not every BSC 5 may be capable of accessing IP network 3. It is also understood that a BSC 5 which may be capable of accessing IP network 3 may typically be capable of accessing a limited number of IP applications. For instance, an IP capable BSC 5 may utilize a specific ISP 7 in accessing IP network 3. Due to the fact that BSCs of mobile communications network 2 and thus the cells corresponding thereto provide different IP applications and/or possess different IP based capabilities, the present invention allows a subscriber of mobile communications network 2 to select preferred capabilities for a cell to possess in order to communicate therewith. Specifically, the present invention allows a subscriber to identify a preference for a cell/B S C which supports particular IP based applications with which the subscriber may communicate. The mobile communications network 2 utilizes the identified cell preference in selecting a cell to communicate with the subscriber's terminal 9, such as when mobile communications network 2 performs cell handover procedures or while camping-on a cell. To facilitate the process of selecting a cell preference and assigning a cell to communicate with a terminal 9, information regarding network 2 is preferably transmitted to terminal 9. The information transmitted by mobile communications network 2 to a terminal 9 preferably informs terminals 9 ofthe capabilities of each cell. In other words, for each cell, mobile communications network 2 provides a list of services and/or applications, including IP based applications, which are accessible thereby. In a preferred embodiment ofthe present invention, the Broadcast Control Channel (BCCH) is modified to include this cell capability information. In this way, a terminal 9, upon receiving the cell capability broadcast, is capable of deterrniningthe cell capabilities ofthe cell presently serving terminal 9 and its neighboring cells.

As stated above, the present invention allows for the selection of a cell preference for use in assigning a terminal 9 to a cell within mobile communications network 2. Referring to Figure 2, terminal 9 preferably includes an interface 20 which is coupled to transceiver

21 to receive the BCCH information pertaining to cell capabilities and to generate the necessary signals for presenting the cell capabilities to the subscriber on display 22. Display

22 preferably further displays the presently assigned cell, its capabilities, and/orthe service being provided to the subscriber.

Further, terminal 9 allows for the selection or identification of a cell preference for use in assigning teπriinal 9 to a cell, such as during a handover procedure or while camping- on a cell. The cell preference may be entered into terminal 9 by the subscriber using keypad

23. Alternatively, the cell preference maybe stored, either permanently or otherwise, on a SIM card 24 which is operatively coimectible to terminal 9. By possessing a number of SIM cards having stored thereon different cell capability preferences, terminal 9 may be configured with different cell capability preferences simply by inserting different SIM cards 24 therein.

The present invention allows mobile communications network 2 (Figure 1) to determine the capabilities of terminals 9 located therein. In particular, a terminal 9 preferably communicates to mobile communications network 2 its IP based capabilities. For example, the information may indicate whether terminal 9 complies with a certain suite of specifications, such as H.323 or SIP. Terminal capability information may be utilized by mobile communications network 2 in reaching cell assignment decisions, such as during cell handover or camping on a cell, by giving greater preference to assigning an IP capable cell to a terminal 9 which prefers communication with an IP capable cell and which itself is IP capable. Specific channel types or target cells could be selected for assignment to a terminal 9 based upon the terminal capability information. In a preferred embodiment ofthe present invention, the IP based capabilities of a terminal 9 are added to the GSM classmark corresponding to terminal 9 for communication to mobile communications network 2. In addition, the subscriber profile, stored in a Home Location Register (HLR) 10, may preferably indicate whether IP support for a terminal 9 is preferred or forbidden. This profile information may be downloaded and used together with the terminal capability information in the classmark in assigning a cell to serve terminal 9.

The operation ofthe present invention will now be described with reference to Figures 3 -5. In performing a cell handover operation in which cell selection is based in part upon the user's communication preferences, terminal 9 monitors the signal strength of cells in the area thereof at step 30. In the event one or more cells whose transmissions terminal 9 measured is a preferred cell or otherwise possesses preferred communication capabilities, terminal 9 sends preferred cell capability information to mobile communications network 2 at step 31. For example, terminal 9 may send a cell preference listing to mobile communications network 2. Next, if mobile communications network 2 determines that, based upon the preferred cell information sent by terminal 9, the new cell for communicating with terminal 9 is associated with a different BSC 5, then the channel preference corresponding to the cell capability preferences is sent to the B SC 5 corresponding to the new cell at step 32. In this way, BSC 5 is aware of the preferred channel type and equipment which is needed to support it.

It is noted that the serving MSC 4 may not know the preferred channel type corresponding to the preferred cell capability preference of terminal 9. Consequently, MSC verifies that the preferred cell capability for the best cell is possible at step 33. If the preferred cell capability preference is not possible and/or compatible, then the handover operation to the selected cell is rejected at step 34. Alternatively, if it is determined that the preferred cell capability preference is possible for the best cell, then terminal 9 is handed over thereto at step 35.

Figure 4 illustrates the process for selecting a cell for terminal 9 while "camping on" a cell. Initially, each base transceiver station (BTS) 6 broadcasts the IP capabilities, if any, for the cells corresponding thereto for reception by terminal 9 at step 41. Next, interface 20 interprets the cell IP capability information and displays the information on display 21 at step 42. At this point, a cell capability preference may be identified at step 43. This identification may be undertaken by the subscriber manually entering the cell capability preference using terminal keypad 23 or by terminal 9 reading the cell preference from SIM card 24 connected thereto.

In the event terminal 9 has indicated to mobile communications network 2 that terminal 9 is to be camped onto a cell selected or preferred thereby, then terminal 9 is camped onto the selected cell at step 44. If the cell camped onto during step 44 is in a new location area, then a location update is performed at step 45.

The steps for performing a location update in the serving MSC 4 and corresponding VLR is illustrated in Figure 5. Upon a reception location update request from terminal 9 at step 51 , MSC 4 receives and stores the classmark therefor at step 52. The classmark may include cell capability preference information for terminal 9. If it is determined that terminal 9 is not registered with MSC 4, MSC 4 notifies the HLR 10 corresponding to terminal 9.

HLR 10 thereupon sends data pertaining to terminal 9 and including its cell capability preferences to MSC 4 at step 53. Thereafter, the subscriber prol-Ue for terminal 9 is stored within MSC 4 and/or its corresponding VLR at step 54.

Although the preferred embodiments ofthe system and method ofthe present invention have been illustrated in the accompanying drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the spirit ofthe invention as set forth and defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A communications system, comprising: at least one mobile communication network, the mobile communication network including at least one base station, the base station serving a plurality of cells within the mobile communication network, at least one of said cells accessing a packet-switched network; at least one mobile station including an identification means therein for identifying respective preferred service-related capabilities of a given plurality of said cells for serving said mobile station, said respective preferred service-related cell capabilities including cell accessibility to the packet-switched network; and an assignment means for assigning said mobile station to a given one of said given plurality of said cells in the mobile communication network based upon said respective preferred cell service-related capabilities.

2. The system of claim 1, further including: an indication means for indicating to said mobile station service-related capabilities of at least one of said plurality of cells in the mobile communication network.

3. The system of claim 2, wherein: said service-related capabilities of said at least one of said plurality of cells indicated by said indication means include an indication whether said at least one of said plurality of cells is capable of accessing the packet-switched network.

4. The system of claim 2, wherein: said indication means transmits said service-related capabilities of said at least one of said cells in the system to said mobile station as a BCCH signal.

5. The system of claim 2, wherein: said indication means includes circuitry for displaying said service-related capabilities of said at least one of said cells in the mobile communication network by said mobile station.

6. The system of claim 1, further including: an informing means for informing the mobile communication network by said mobile station of a service-related capability thereof.

7. The system of claim 6, wherein: said informing means transmits said service-related capability of said mobile station as classmark information in a signal.

8. The system of claim 6, wherein: said service-related capability of said mobile station includes an indication of whether said mobile station is capable of executing an application from the packet-switched network.

9. The system of claim 6, wherein: said service-related capability of said mobile station is maintained in the mobile communication network as part of a subscriber profile.

10. The system of claim 1, further including: a SIM card operatively connectible to said mobile station and having stored thereon said respective preferred service-related cell capabilities; and said assignment means selects a cell in the mobile communication network based upon said respective preferred service-related cell capabilities stored on said SIM card.

11. The system of claim 1 , wherein: said respective preferred service-related cell capabilities include a cell capability to access an Internet Protocol application associated with the packet-switched network.

12. A method for providing one or more telephone-related services to a terminal in a mobile communications network having a plurality of cells therein, at least one of said cells being capable of accessing an Internet Protocol (IP) application, the method comprising the steps of: identifying preferred service-related capabilities for the cells in the mobile communications network for serving a teπninal therein, the preferred service-related cell capabilities including cell accessibility to the IP application; and selecting one of said cells ofthe mobile communications network to serve the terminal based upon the identified preferred service-related cell capabilities.

13 The method of claim 12, further including the step of indicating to the terminal service-related capabilities ofthe cells in the mobile communications network, the service-related cell capabilities including an indication whether one or more ofthe cells is capable of accessing the IP application

14 The method of claim 13 , wherein : said indicating step comprises the step of broadcasting the service-related cell capabilities within the mobile communications network.

15 The method of claim 13, further including the step of displaying the service-related cell capabilities indicated in said indicating step on the terminal

16 The method of claim 12, further including the step of informing the mobile communications network by the terminal whether the terminal is capable of utilizing the IP application.

17. The method of claim 16, wherein: said infoπning step comprises the step of transmitting classmark information in a signal which indicates whether the terminal is capable of utilizing the IP application.

18. The method of 16, further including the step of: storing the capability ofthe terminal to utilize the IP application as a subscriber profile.

19. An arrangement for use in a mobile communications system having a plurality of cells, comprising: at least one mobile station; and a configuration means, associated with said mobile station, for selectively configuring a cell preference for providing a service to said mobile station by one or more of said cells within the mobile communications system which supports an Internet Protocol (IP) based application.

20. The arrangement of claim 19, further including: a selection means for selecting one of said cells for serving said mobile station based upon said configured cell preference.

21. The arrangement of claim 20, further including: an indication means for indicating cell information to said mobile station, said cell information including whether one or more of said cells in the mobile communications system supports the IP based application.

22. The arrangement of claim 21, wherein: said indication means broadcasts whether one or more of said cells in the mobile communications system supports the IP based application.

23. The arrangement of claim 21 , wherein: said mobile station includes a display for presenting said cell information provided by said indication means.

24. The arrangement of claim 19, wherein: said configured cell preference for serving said mobile station is chosen by a user of said mobile station using said configuration means.

25. The arrangement of claim 19, wherein: said configuration means includes a SIM card operatively connectible to said mobile station and having stored thereon said configured cell preference.

26. The arrangement of claim 19, wherein: the IP based application comprises an Internet Service Provider (ISP) accessible from within the mobile communications system.