FIELD OF THE INVENTION

The present invention, generally relate to telecommunications, and, more particularly, to cellular networks and network selection during manual PLMN search

BACKGROUND OF THE INVENTION

User Equipment (UE) has to register on a Public Land Mobile Networks (PLMN) to get services. When UE is registered on a PLMN, the operator of the PLMN gets revenue when the UE uses the services. So operator would like the UE to be registered on his network as much as possible. During manual PLMN search UE looks for cells from available PLMN and display the list of PLMN to the user to choose from. Only one carrier name per available PLMN ID is shown on the User Interface (UI). When user makes his selection by selecting his preferred carrier, UE tries registration on the user selected PLMN to services to the user.

Currently when a manual search is triggered by the user, only one carrier/ operator name is displayed for each unique PLMN ID. For each unique PLMN ID, information about the highest signal strength cell (e.g. mcc, mnc, lac, cell id etc.) is passed on by the lower layers and then UI maps the associated name string to display based on the information received about this cell from lower layer. Operators use Elementary File – Operator PLMN List (EF-OPL), content of which is as shown in Table 1, to let UE display their preferred names in the areas defined by MNC/MCC and Location Area Code (LAC) in EF-OPL (in case they want to display the name other than defined in SE13 for an MCC/ MNC combination).

Bytes Description M/O Length
1 to 7 Location Area Identity M 7 bytes
8 PLMN Network name record identifier M 1 byte

Table 1
Typically, operators code the sharing/ roaming areas in EF-OPL and map them to Elementary File – PLMN Network Name (EF-PNN) which has a network name to display when UE is in the area defined in EF-OPL record; as shown in tables 2A and 2B as shown below.

EF-OPL
Rec # MCC MNC LAC-1 LAC-2 PNN Record Ptr
1 310 170 0000 3000 2

Table 2A

EF-PNN
Rec # PNN
1 T-Mobile
2 T-Mobile
3 T-Mobile

Table 2B
During manual search and also in idle mode, EF-OPL has higher priority for network name display compared to SE13 table; the SE13 entry for a 310,170 PLMN is {310, 170, NETWK_TYPE_PCS_1900, “AT&T,”AT&T”}. To map the network name corresponding to this cell, UE first looks into EF-OPL to match the MCC-MNC and LAC information of the highest signal strength cell against entries present in the EF-OPL. If match is found then UE displays the associated name from EF-PNN (pointed by EF-OPL entry), otherwise UE displays name from hard-coded SE13 table stored in UE ROM.

SUMMARY OF THE INVENTION

In view of the foregoing, an embodiment herein provides a method to list all available networks during a manual PLMN search in a mobile device subscribing to one carrier which shares PLMN with other carrier(s) for providing services to its subscriber in shared PLMN, by retrieving available PLMN list from lower layers; for each of the PLMN in the retrieved list, checking if a PLMN is shared by checking the shared PLMN entry in said EF-OPL; retrieving all LACs for an identified shared PLMN; checking if all LACs for shared PLMNs resolve to a same name; and retrieving all network names to be displayed, where the mobile device is in an overlapping area of different carriers sharing the same PLMN.

These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows overlapping cells in a cellular network;

FIG. 2 shows the content of EF-OPL;

FIG. 3 shows a mobile device display showing the carrier list based on signal strength;

FIG. 4 shows the content of EF-OPL in accordance with various embodiments as disclosed herein;

FIG.5 shows a mobile device display showing the carrier list in accordance with various embodiments as disclosed herein;

FIG. 6 shows a method in accordance with various embodiments as disclosed herein; and
FIG. 7 shows a method in accordance with various embodiments as disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

As mentioned, there remains a need to show multiple carrier names when a PLMN is shared. The embodiments herein achieve this by defining information related to sharing of PLMN in EF-OPL, and providing a methodology where a User Equipment (UE) checks all available cells of the shared PLMN to see whether cells from different operators are available or not when manual search is done in the areas of shared PLMN. Referring now to the drawings, and more particularly to FIGS. 1 through 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

A method based on EF-OPL is described by which UE gives a user more options to select his preferred network during manual search in overlapping areas of shared PLMNs. In this method for the same (shared) PLMN code UE looks for presence of different operator cells and present them to the user for his/her selection. During manual search in overlapping areas of shared or roaming PLMN users are given options to select a preferred Operator in case preferred carrier cells have less signal strength compared to other carrier sharing the PLMN.

When manual search is done in the areas of shared PLMN, UE checks all available cell of the shared PLMN to see whether cells from different operators are available or not (based on EF-OPL, PLMN ID, LAC and SE13 table). An extra byte is added to the currently existing 8 bytes of EF-OPL, resulting in a total of 9 bytes of EF-OPL. The extra byte, known as Shared PLMN tag, indicates that PLMN identified in Location area identity field is shared between two or more operators. The content for EF-OPL is as shown in table 3 and an example for said EF-OPL is as shown in FIG. 4, where bit 9 which contains “8A” is said shared PLMN tag.

Bytes Description M/O Length
1 to 7 Location Area Identity M 7 bytes
8 PLMN network name record identifier M 1 byte
9 Shared PLMN tag O 1 byte

Table 3

Once sharing of PLMN codes is identified by checking said ninth byte, RR software is requested to give all LACs available for said shared PLMN ID. For a PLMN ID, IE code (Shared PLMN Tag) is checked - if present, a hardcoded table is searched for second PLMN name. Said hardcoded table is stored in memory ROM (and is called SE13). If cells from different operators are found, then UE displays names of different operators in manual search result, as shown in FIG. 5. Network name resolved from EF-OPL, as shown in tables 4A and 4B, has higher priority in said display than names resolved from SE13, an example of an SE13 entry for 310,170 PLMN is {310, 170, NETWK_TYPE_PCS_1900,”AT&T”, “AT&T”}.

EF-OPL
Rec # MCC MNC LAC-1 LAC-2 PNN Record Ptr
1 310 170 0000 3000 2


Table 4A

EF-PNN
Rec # PNN
1 T-Mobile
2 T-Mobile
3 T-Mobile
Table 4B

FIG. 6 shows the flow of the algorithm for showing manual PLMN list to a user. On said user triggering a manual search (601), a list of n available PLMNs is created (602). A check is made to see if available PLMN is shared, as defined in EF-OPL (603). If said available PLMN is not shared, n network names are displayed (604). If said available PLMN is shared, then a further check is carried out to see if all available LACs (cell) of shared PLMN resolves in the same network name (605). If all available LACs (cell) of shared PLMN resolve in the same network name (605), then n network names are displayed (604), otherwise (n+1) PLMN or network names are displayed (606).

FIG. 7 shows the flow of the algorithm to decide a cell on which registration attempt is to be made, after user has made a selection. Once said user has made a selection (701), a check is made if selected PLMN is shared, as defined in EF-OPL (702). If selected PLMN is shared, a cell of operator chosen by user is selected (703) i.e. LAC/PLMN ID of said cell resolves to name of said network selected by said user and registration is attempted on said selected cell (705). If selected PLMN is not shared, any best suitable and available cell is selected for said PLMN (704) and registration is attempted on said selected cell (705). In other words, when user selects an operator, UE has to take care that cell from operator chosen by user is selected and registration is attempted on said appropriate cell.

With the embodiment disclosed above, a user is given the option of selecting his preferred PLMN. In addition to this, operators can also increase revenue by giving options to user to select his preferred PLMN in overlapping areas of shared/roaming PLMNs and also, provide a better user experience.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.

We Claim:

1. A method to list all available networks during a manual PLMN search in a mobile device subscribing to one carrier which shares PLMN with other carrier(s) for providing services to its subscriber in shared PLMN, the method comprising the steps of:

a) retrieving available PLMN list from lower layers;

b) for each of the PLMN in the retrieved list, checking if a PLMN is shared by checking the shared PLMN entry in said EF-OPL;

c) retrieving all LACs for an identified shared PLMN;

d) checking if all LACs for shared PLMNs resolve to a same name; and

e) retrieving all network names to be displayed,

where the mobile device is in an overlapping area of different carriers sharing the same PLMN.

2. A method as in claim 1, wherein the step of checking shared PLMN entry further comprises of checking the shared PLMN tag in said EF-OPL, where the shared PLMN tag comprises of information indicating that the PLMN is shared between 2 or more operators.

3. A method as in claim 1, wherein the step of retrieving all shared network names to be displayed further comprises of looking into a hard coded (SE13) table for a second PLMN name.

4. A method as in claim 1, wherein the step of retrieving all shared network names to be displayed further comprises of looking in EF-OPL for a second PLMN name

Dated this 15th day of February 2008

Signature

SANTOSH VIKRAM SINGH
Patent Agent
Agent for the applicant

ABSTRACT

Disclosed herein is a method to list all available networks during a manual PLMN search in a mobile device subscribing to one carrier which shares PLMN with other carrier(s) for providing services to its subscriber in shared PLMN, by retrieving available PLMN list from lower layers; for each of the PLMN in the retrieved list, checking if a PLMN is shared by checking the shared PLMN entry in said EF-OPL; retrieving all LACs for an identified shared PLMN; checking if all LACs for shared PLMNs resolve to a same name; and retrieving all network names to be displayed, where the mobile device is in an overlapping area of different carriers sharing the same PLMN.