ZA201006801B

ZA201006801B - Telecommunications networks

Info

Publication number: ZA201006801B
Application number: ZA2010/06801A
Authority: ZA
Inventors: J Rich Cornel; Ragunandan Igolkisshore
Original assignee: Multinet Wireless (Pty) Ltd
Priority date: 2009-09-22
Filing date: 2010-09-23
Publication date: 2011-08-31

Description

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FIELD OF THE INVENTION | NIN

This invention relates to telecommunication networks.

BACKGROUND TO THE INVENTION

In underserved rural areas, the only form of communication available is often a GSM or other mobile cellular service with full mobility and prepaid service at high cost. There is a market need for an overlaid wireless local loop (WLL) type of wireless service for residential and work areas, particularly in rural areas, which connects subscribers to the nearest PSTN exchange to emulate a traditional wireline type of service. Provision of power is a frequent problem therefore solar-power compatibility is a requirement with low-power network base stations. Such a service however may have limited mobility and fragmented coverage due to the low power capability. Furthermore, underprivileged users in rural areas may already own a cellular mobile handset and cannot afford to purchase yet another phone. There is therefore a need for such users to be able to use their existing cellular mobile handsets and have a means to be able to automatically or manually switch between a cellular mobile and WLL network using an existing handset.

Cellular phones are equipped with a Universal Integrated Circuit Card (UICC) which is a plug-in smartcard which ensures the integrity and security of all kinds of personal and network data and may contain several applications. The UICC smart card consists of a processor unit (CPU), non-volatie memory (ROM), volatie memory (RAM) and input/output circuits (1/0). In a GSM network, the UICC contains a SIM application, in a

UMTS network a USIM application and in CDMA a CSIM application. A card with all 3 features is called a removable user identity card, or R-UIM. Thus, the R-UIM card can be inserted into CDMA, GSM, or UMTS handsets, and will work in all three cases.

To co-exist on two different operators’ wireless networks may require a phone to have two separate UICC’s or at minimum two separate applications. Most phones deployed in the field have only one UICC capability. Therefore a means has to be found to be able to use the existing UICC and provide a mechanism for seamless switching between two networks. These cards are specific to, and issued by, the respective network operator and the subscriber and network details are held on this card which the phone accesses to register with, and use, the network. Alternative network details for roaming purpose are also held on the card but typically roaming network switching is only carried out in foreign countries where there is no home country network. There is normally no facility for roaming in-country unless the respective networks have a network co-operation agreement.

By way of example the following describes a typical GSM cellular implementation but can equally apply in principle to any other network. On a GSM SIM application, various types of facilities and information are held which could be common to any network. The essential unique parameters held which are required for a subscriber to register on a network, are outlined below: i) IMSI number which is a unique international number for the subscriber made of

MCC (Mobile Country Code), MNC (Mobile Network Code) and the Subscriber

Number. ii) MSISDN number which is an operator-aliocated network number used to dial the user and is different from the IMSI iii) Secret Key Ki (IMSI specific) iv) A3 algorithm for authentication (network specific) v) A8 algorithm for key generation (network specific) vi) Home PLMN Number (HPLMN) vii) PLMN Selector (EFpiunser) viii) ~~ Prioritised Network Selector (EF pi mnwact, EF opLmnNwAcT) ix) Forbidden Networks (EFep mn)

The IMSI, secret key and algorithms are used to authenticate subscribers and to generate session keys for encryption. HPLMN defines the home network and other associated networks for roaming when HPLMN is not available. To enable switching to another independent non-associated network, HPLMN needs to be superceded by the second network HPLMN which is not covered by the 3GPP specifications for GSM. In normal circumstances this would be accomplished by changing the SIM card.

Legacy WLL systems in the past were typically based on DECT technology and utilized

TDMA point-to-multipoint microwave links to backhaul to the nearest telephone exchange a number of DECT base station towers which were strategically located to x provide coverage to populated conurbations. Such systems have fallen into disuse but the towers represent a significant-cost resource to be exploited for a new invention.

In order for subscribers on the PSTN to be able to dial remote WLL subscribers in a simple friendly manner, DECT and similar WLL solutions used conventional dedicated point-to-point wireless telephone circuits and associated numbering systems in order to appear as a simple extension of the PSTN telephone numbering system. In normal circumstances, introduction of a WLL system with its own unique numbering methodology overlaid on an existing mobile network with compatible common-use phones creates a major problem as users would need to know two numbers for each subscriber which is user unfriendly and the user would need to change the SIM to switch between networks.

THE INVENTION

According to the invention, a wireless telephonic device is provided for manually or automatically switching between two non-associated networks, the device including an embedded software program, and a single internal universal integrated circuit card (UICC) and programmable logic means incorporating digital memory storage; the software application being embedded within the programmable logic means and being further adapted to manage the switching between the networks. in the context of this specification, manually means that the user retains full control and decides himself whether to switch from one network to another rather than relying on an automated process controlled by the device.

The networks may have non-identical radio coverage profiles resulting in the phone having to switch between the networks in order to maintain communication coverage.

One of the networks will be preselected as the priority “home” network.

In the preferred form of the invention, the programmable logic means contains a virtual partial UICC with key parameter data for identifying the priority home network; the programmable logic means being programmed to enable the virtual UICC parameters or

+ the UICC SIM parameters to be used for network identification, selection and reselection in response to the presence or absence of radio signal of one or both of the networks; the programmable logic means being further adapted to select or reselect the priority home network defined by the virtual UICC in preference to the public land mobile network (PLMN) network defined by the UICC SIM when a suitable cell and signal is identified for the home network, notwithstanding any forbidden network parameter or other programmed in the UICC SIM which may bar the home network.

To accomplish switching between a priority home network and another independent

PLMN using a mobile phone with single UICC, a master-slave UICC arrangement is required whereby the master UICC is a virtual partial UICC which has master control over the slave resident UICC and manages the switching between the two HPLMN codes. The virtual UICC will be resident as a software application in non-volatile memory of the phone and will be programmed with the essential parameters and any other associated information required to register with and use the home network. Common parameters which are applicable to both networks (e.g. for SMS messaging, phone book, etc) will be obtained from the UICC slave.

In a GSM application, the UICC is a SIM and the virtual UICC is a virtual partial SIM.

In a 3G W-CDMA application, the UICC is a USIM and the virtual UICC is a virtual partial

USIM.

Similarly, in a CDMA 2000 application, the UICC is a CSIM and the virtual UICC is a virtual partial CSIM.

An R-UIM comprises the UICC for an application which encompasses all three of the above applications and in this case the virtual UICC comprises a virtual partial R-UIM.

In the preferred form of the invention, the programmable logic means is adapted to select the PLMN network defined by the UICC slave when a suitable cell and signal for the home network is lost.

The programmable logic means may further be adapted to use all other non-network- specific parameters on the UICC slave for features and services and/or to store and retrieve data (e.g. TMSI) related to network and user operations requiring UICC slave interaction.

The embedded software program may be downloaded to the subscriber's mobile phone by an agent of the home network using a programmer device for this purpose. On OTA- capable phones and using OTASP (over-the-air service provisioning), the program may also be downloaded automatically.

In order to provide a user friendly means for other network subscribers to be able to dial a subscriber on the home PLMN, a simple numbering plan is required for the home

PLMN which does not require other network subscribers to remember multiple different numbers for a subscriber. To provide a convenient number plan, the home network shall use the subscriber's existing cell phone number (e.g. Oxxxxxxxx) from his subscribed network and append the digits 01 (optionally 02, 03, etc) as a prefix to form the home network number (e.g. 010xxxxxxxxx). This number may be loaded into the virtual UICC either automatically by the program reading the number from the physical UICC or manually by a home network agent. The home network agent shall also load the virtual

UICC with other necessary parameters like the unique IMSI for the phone to operate on the home network. This new dial number will be registered on the home operator's HLR by whatever method preferred by the operator together with the provisioned IMSI number for that virtual SIM. The phone can be dialled simply from PSTN or any other network using the composite mobile number (home network number). The 010 code can be simply used by the PSTN to route calls to the Home PLMN as codes with a third digit as 0 are not commonly used. Other networks will route 01 dialled calls to the PSTN for onward relay to the Home PLMN.

According to a second aspect of the invention, a UICC is provided for a wireless telephone, the UICC being adapted to manage the switching of the telephone between the networks in order to maintain communication coverage.

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In the preferred form of the invention, the UICC comprises a virtual partial UICC for use in a telephone with a single UICC, the virtual partial UICC having master control over the (slave) UICC resident in the telephone.

Also in the preferred form the virtual partial UICC is resident as a software application in the non-volatile memory of the phone, the UICC being programmed with the essential parameters and other associated information required to register with and use the home network.

In the preferred form, the networks have non-identical radio coverage profiles.

EMBODIMENT OF THE INVENTION

An embodiment of the invention is described below with reference to the accompanying drawings, in which:

Figure 1 is a schematic representation of the adaptation of a mobile phone 10.

The phone is normally equipped as standard with a Universal Integrated Circuit Card (UICC),12, being a SIM, USIM, CSIM or R-UIM according to network type. An embedded software program 14 for a second virtual UICC is loaded into the phone programmable logic means to provide an additional set of HPLMN, IMSI and other parameters for registering with and using a second overlaid PLMN. _N [I Universal Integrated k Fal

SLAVE ircui a 11] (PLMNz) 1 CireuitCard (SIM, etc) = \

MASTER | Embedded Software, Ji TREN! (Home PLMN) | Program for Virtual UICC B - 18

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FIGURE 1

Figure 2 is a schematic representation of the operation of the phone in the presence of dual networks.

An incumbent PLMN provides mobile coverage in a wide area cell (PLMN2 cell) from a high site tower 16. An overlaid independent network with towers providing areas of cell coverage for populated areas is constructed as shown by the Home PLMN cells 18 and 20. This typically will comprise solar-compatible low-power inexpensive outdoor base station of an industry-standard cellular wireless technology (e.g. GSM) on a typical

DECT-type tower (new or existing) strategically located near populated conurbations. em 7 ’ Te

Pe : Rh. 7 < 3 : N . d PLMN 2 hs / m/ BL oo , i I —

HOME | \. d : tT : Fa : ~~ PLAN I} oT 1 ee \

EE v TE 3 Lo : HOME 3 =~ «

Co 1 Central CE LCEL2 .

SE P81 Highsite EE ‘ : mgg am

BE m=) Hi | y rain 4 [P BACKHAUL [| Area Telephone Media e.g. WIMAX ) ] Exchange Gateway So } } oo i

FIGURE 2

The base stations will not use industry-standard conventional point-to-point Time

Division Multiplex (TDM) circuits on the backhaul but will employ Internet Protocol (IP) packet data transmission techniques instead which will reduce transmission cost and, more importantly, will allow local calls to be switched at the base station rather than being backhauled to a central switch in the normal industry custom-and practice manner.

Therefore wireless IP data links 22, 24 typically provided by a WiMAX or other

Claims

TI 1010/0680 ly eee CLAIMS: CL

1. A wireless telephonic device is provided for manually or automatically switching between two non-associated networks, the device including an embedded software program, and a single internal universal integrated circuit card (UICC) and programmable logic means incorporating digital memory storage; the software application being embedded within the programmable logic means and being further adapted to manage the switching between the networks.

2. A wireless telephonic device according to claim 1 in which the networks have non- identical radio coverage profiles resulting in the phone having to switch between the networks in order to maintain communication coverage.

3. A wireless telephonic device according to claim 1 in which one of the networks is preselected as the priority “home” network.

4 A wireless telephonic device according to claim 1 in which the programmable logic means contains a virtual partial UICC with key parameter data for identifying the priority _ home network; the programmable logic means being programmed to enable the virtual UICC parameters or the UICC SIM parameters to be used for network identification, selection and reselection in response to the presence or absence of radio signal of one or both of the networks; the programmable logic means being further adapted to select or reselect the priority home network defined by the virtual UICC in preference to the public land mobile network (PLMN) network defined by the UICC SIM when a suitable cell and signal is identified for the home network, notwithstanding any forbidden network parameter or other programmed in the UICC SIM which may bar the home network.

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5. A wireless telephonic device according to any of the above claims in which a master- slave UICC arrangement is provided to facilitate switching between a priority home network and another independent PLMN; the master UICC is a virtual partial UICC which has master control over the slave resident UICC and manages the switching between the two HPLMN codes.

6. A wireless telephonic device according to claim § in which the virtual UICC is resident as a software application in non-volatile memory of the phone and will be programmed with the essential parameters and any other associated information required to register with and use the home network.

7. A wireless telephonic device according to claim 5 and claim 6 in which common parameters which are applicable to both networks, are obtained from the UICC slave.

8. A wireless telephonic device according to any of the above claims in which the application is a GSM application, and the UICC is a SIM and the virtual UICC is a virtual partial SIM.

9. A wireless telephonic device according to claims 1 to 7 in which the application is a 3G W-CDMA application and the UICC is a USIM and the virtual UICC is a virtual partial USIM.

’ v A wireless telephonic device according to claims 1 to 7 in which the application is a CDMA 2000 application and the UICC is a CSIM and the virtual UICC is a virtual partial CSIM.

11. A wireless telephonic device according to claims 1 to 7 in which the application comprises a combination of GSM, 3G W-CDMA and CDMA 2000 applications, the UICC comprising an R-UIM, the virtual UICC comprising a virtual partial R-UIM.

12. A wireless telephonic device according to any of the above claims in which the programmable logic means is adapted to select the PLMN network defined by the UICC slave when a suitable cell and signal for the home network is lost.

13. A wireless telephonic device according to any of the above claims in which the programmable logic means is adapted to use all other non-network-specific parameters on the UICC slave for features and services and/or to store and retrieve data (e.g. TMSI) related to network and user operations requiring UICC slave interaction.

14. A wireless telephonic device according to any of the above claims in which the embedded software program is downloadable to the subscriber's mobile phone by an agent of the home network using a programmer device for this purpose.

9040/0680¢ [a [3

15. A wireless telephonic device according to claims 1 to 13 in which the subscriber's mobile phone is OTA -— capable, the embedded software program is automatically downloadable using over-the-air service provisioning (OTASAP).

16. A wireless telephonic device according to any of the above claims in which a numbering plan | provided in which the home network makes use of the subscriber's existing cell phone number from his/her subscribed network with the digits 01 (zero one), or the like, appended thereto as a prefix to form the home network number.

17. A wireless telephonic device according to claim 16 in which the home network number is loaded into the virtual UICC either automatically by the program reading the number from the physical UICC or manually by a home network agent.

18. A wireless telephonic device according to claim 17 in which the home network agent shall load the virtual UICC with other necessary parameters for the phone to operate on the home network.

19. A wireless telephonic device according to any of the above claims in which the home network number is registered on the home operator's HLR by whatever method preferred by the operator together with the provisioned IMSI number for that virtual SIM.

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20. A wireless telephonic device according to any of the above claims in which the phone is dialled simply from PSTN or any other network using the home network number.

21. A UICC for a wireless telephonic device according to any of the above claims which is adapted to manage the switching of the telephone between the networks in order to maintain communication coverage.

22. A wireless telephonic device substantially as described with reference to the accompanying drawings. Dated this 22 day of September 2010 MORRISON kfm INC. © APPLICANTS’ PATENT ATTORNEYS