Title of Invention	A METHOD OF PERFORMING OPTIMIZED FREQUENCY BAND SELECTION FOR OBTAINING SERVICE FROM A NETWORK
Abstract	The invention relates to the field of mobile communication system. In particular, the invention proposes a method for selecting a band by using a SE.13 table for a multi-mode user equipment (UE) which supports multiple bands in GSM and UMTS. The UE can use the SE 13 table to arrive at a preferred band group. The UE can use this preferred band group to search for service. The UE can update this table whenever it finds service on a band for a PLMN not available in the SE 13 table. UE can optimize its scan further by identifying the preferred band group for normal service as well as for limited service. For HPLMN Search/high priority PLMN search also, UE can restrict its scan for bands from SE 13 table(updated) of higher priority PLMN than the currently camped PLMN.

Title of Invention

A METHOD OF PERFORMING OPTIMIZED FREQUENCY BAND SELECTION FOR OBTAINING SERVICE FROM A NETWORK

Abstract

The invention relates to the field of mobile communication system. In particular, the invention proposes a method for selecting a band by using a SE.13 table for a multi-mode user equipment (UE) which supports multiple bands in GSM and UMTS. The UE can use the SE 13 table to arrive at a preferred band group. The UE can use this preferred band group to search for service. The UE can update this table whenever it finds service on a band for a PLMN not available in the SE 13 table. UE can optimize its scan further by identifying the preferred band group for normal service as well as for limited service. For HPLMN Search/high priority PLMN search also, UE can restrict its scan for bands from SE 13 table(updated) of higher priority PLMN than the currently camped PLMN.

Full Text	FIELD OF THE INVENTION The present invention, in general, is related to a band selection method particular to a mobile communication system, which supports plurality of bands and may contain different communication access technologies. This invention is also related to using of a GSM association released SE.13 table, which consists of network code names, supported bands and other information. More particularly, the present invention relates to optimized method of band selection in a multi band GSM/3G mobile. DESCRIPTION OF THE RELATED ART A multi band/mode mobile communication system which supports multiple bands i.e. GSM 850, GSM 1900, GSM 900, GSM 1800, UMTS 850, UMTS 1900, and UMTS 2100 etc can be operated in any of the supported bands. When a UE is looking for the service on a network or a cell it should start scanning for all the frequencies corresponding to a frequency band to know the existence of the service in that particular band. There are several methods to get the service in a multi band mobile communication system. One method is scanning for all the bands to know the existence of a service. Another method is giving an option to the user to choose the particular bands and modes for the scanning. Some more existing methods says that maintaining a supported bands for each MCC in a non volatile memory and update the same when ever UE comes to know the new band existence. Whenever mobile station powered on OR lost the service on current cell then it should start searching for the cells to get service. One way of finding the service is searching for all the frequencies corresponding to supported bands by UE, but it will consume more power since that place may not be required to look for the service in all the UE supported bands. Saving the power of a Mobile station is a very important aspect with respect to user point of view. The second method is giving an option to the user for selecting the band and mode combinations on which UE should look for the service. The problem with this method is user should have good knowledge about the frequency of bands and modes existence at each geographical area to get the better results. Another method is selecting particular bands for each MCC out of all the UE supported bands by using a non-volatile memory table which consists of allocated bands corresponding to each country. This memory table will be updated whenever UE come across a new system and the band. Here the problem is non-volatile memory for which accessing speed increases. GSM Congress will release a latest SE.13 table on every month; and it contains Country Initials, Organisation, Network, PPCI&N, Abrev. Net. Name, Net. Type (mode and band), MCC, MNC, NCC. Usually GSM mobiles which come to the market will contain the latest SE.13 table available at the time of release. None of the prior arts talks about the updating of SE.13 table when UE come across a new network. As mentioned in the prior art UE will do search for two types of cells. One search is looking for normal service cells and another one is looking for the limited service cells. Initially UE will start searching for normal service cells through which user can get all subscribed services. If UE is not able to find a normal service cell then it will search for limited service cells by considering forbidden PLMN list and forbidden LAI list. The invention is giving a method of a selection of proper bands by using a SE.13 table for a multi mode mobile communication device which supports multiple bands in GSM as well as UMTS. In Automatic band selection mode UE can prepare two type bands list which are "preferred band list" and "non-preferred band list". "Preferred band list" will be prepared based on the current MCC on which UE is camped by looking in to the SE.13 table list. SE.13 list will be stored in read only memory so; that accessing will be faster. In the current method UE will store SE.13 table with the fields MCC, MNC, network name and network type (i.e. band, mode). Whenever UE camped on a cell it will come to know the PLMN id which is MCC, MNC. By using this MCC and SE.13 table; UE will derive the "preferred band list" which are allocated in that country by looking in to SE.13 table. The rest of the bands (which are not present in preferred bands list) will become a "non-preferred band list". Since then whenever UE looses the coverage on current cell it will start scanning on all the frequencies corresponding to the bands of "preferred band list". Additionally, periodically may be one out of X times, UE will do search on "non preferred band list". On power off UE will store the "preferred band list" in to non volatile memory and the same will be used on next power on. In the current proposed method on power on situation first UE will do search on all the frequencies corresponding to "preferred band list". If it is not able to find the service then UE will do the search on all the frequencies corresponding to "non-preferred band list". Once UE finds a cell corresponds to some band then UE will make use of MCC, MNC of that cell and SE. 13 table to derive new "preferred band list". According to GSM congress the SE.13 table will be updated on every month. In the proposed method UE is going to maintain "extension of SE.13 list" in nonvolatile memory. During preferred band search or non-preferred band search if UE come across a new cell who's MCC, MNC are not present in the SE.13 table then UE will add an entry to the "extension of SE.13 list" and same can be used for further derivations of band list. If UE comes to know the network name of this MCC, MNC through OTA message then the same name can be updated in "extension of SE.13 list". "Extension of SE.13 list" will contain Net. Name, Net. Type (mode and band), MCC, MNC. In the proposed method while deriving the preferred band list UE will also considers the forbidden PLMN list which will be present in the SIM. During normal service search the bands corresponding to forbidden PLMN's can be removed from the preferred band list, provided if there are no other PLMN's exist on that particular band in that country. For limited service search we need to consider a different preferred band list. The concept of using MCC, MNC information to determine which bands need to be searched for service has been identified in patent applications US 2006/0194577 and US 2007/0004405. Patent application US 2006/0194577 also mentions storing a set of preferred bands in the user equipment. Further, US 2006/0194577 also seems to disclose the concept of searching for service in 'preferred band' first and for service in 'non-preferred band' occasionally. Updating MCC, MNC information is also mentioned in US 2006/0194577. SUMMARY OF THE INVENTION The present invention relates to the field of mobile communication system. In particular, the invention proposes a method for selecting a band by using a SE.13 table for a multi-mode user equipment (UE) which supports multiple bands in GSM and UMTS. According to the method, a UE stores a SE.13 table having the fields Mobile Country Code (MCC), Mobile Network Code (MNC), network name and network type. Whenever the UE camps on a cell, it finds out its PLMN ID (i.e. MCC, MNC) from the broad cast information of the cell. The UE then uses the SE.13 table to derive a 'preferred band list' which are allocated in that country. The rest of the bands i.e. the bands which are not present in the 'preferred band list', become a part of a 'non-preferred band list'. The UE stores the 'preferred band list' in a non-volatile memory while powering off and uses the list when it is powered on. Now whenever the UE is powered on or loses coverage on a cell, it first scans all the frequencies present in the 'preferred band list'. In addition, the UE scans the frequencies present in the 'non-preferred band list1, one out of X times. The UE will also consider forbidden PLMN list (present in the SIM card) while deriving the preferred band list. The UE has different band groups for 'normal service' scanning and for 'limited service' scanning. Further, the UE also maintains an 'extended SE.13 table' in a non-volatile memory. During the preferred band search or the non-preferred band search, if the UE comes across a new cell which is not present in the SE.13 table, the UE will add this entry to the 'extended SE.13 table'. Accordingly the invention explains a method of optimized band selection by a UE wherein the said UE uses a database to determine a band group to search for mobile service of a region based on MCC where the UE divides plurality of bands it is capable of operating into preferred band group and non preferred band group. The absence of coverage or at power on, UE looks for mobile service in the preferred band for most of the time and occasionally, search for service in the non preferred band. Using the database and a forbidden PLMN list, UE optimize the preferred band by removing the band belonging to forbidden PLMN list from the preferred band group if the particular band is not being used by any other PLMN providing normal service in the region. UE update the database whenever the UE finds other bands for the particular PLMN during occasional searches for non preferred bands. The UE maintains different preferred band groups for normal service scanning and limited service scanning. Normal service preferred band group avoid bands from forbidden PLMN of a particular region where as limited service preferred band group have the entire band for the corresponding PLMNs of a region based on the database. During high priority PLMN searches, UE restrict to the bands of higher priority PLMN of a region based on the database. These and other objects, features and advantages of the present invention will become more apparent from the ensuing detailed description of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1 depicts the first embodiment of invention Figure 2 shows the searching for the service on power-on by UE based on the first embodiment of invention Figure 3 depicts the searching for the service during recovery from lack of coverage based on the first embodiment of invention Figure 4 depicts a flow chart shows the implementation in the UE when the High priority PLMN Search timer expires based on the first embodiment of invention Figure 5 depicts a flow chart shows the second embodiment of invention; which is maintaining the extended SE-13 table. Figure 6 depicts a flowchart is another embodiment of invention which is maintaining different preferred band lists for normal service cell search and limited service cell search Figure 7 shows another embodiment of invention which is updating the network name in "extended SE.13 table" when UE receives an OTA message from network Figure 8 shows the power on procedure by using different preferred bands list for normal service and limited services. Figure 9 explains the procedure should be followed by UE to get in to service with including all above embodiments. Figure 10 shows the high priority periodic PLMN search by including all the above embodiments. DETAILED DESCRIPTION OF THE INVENTION The preferred embodiments of the present invention will now be explained with reference to the accompanying drawings. It should be understood however that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. The following description and drawings are not to be construed as limiting the invention and numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However in certain instances, well-known or conventional details are not described in order not to unnecessarily obscure the present invention in detail. Figure 1 shows the calculation of "preferred band list" and "non preferred band list" based on the MCC of the current camped cell using SE.13 table. Whenever UE camped on a cell then UE will read the MCC (which will be broadcasted by radio network) of the current camped cell and check with SE.13 table for corresponding entry. Based on this MCC entry in SE.13 table UE will calculate the "preferred band list" and "non preferred band list". If this MCC entry is present in SE.13 table then "Preferred band list" is equal to the all bands which are corresponds to this particular MCC in the SE.13 table. Remaining all supported bands by UE will be kept in "non preferred band list". If this MCC entry is not present in SE.13 table then "Preferred band list" is equal to the band of the current camped cell and "non preferred band list" is equal to the all the remaining bands supported by UE. The above calculated band lists will be used accordingly by the UE; for the normal service search and limited service search. During power off UE can store "Preferred band list" in non-volatile memory and the same can be used for the next power on. Figure 2 shows the searching for the service during power-on by UE based on the first embodiment of invention. During power on UE will read the "preferred band list" which was stored in NV and the same will be used for the search. First UE will do the normal service search and limited service search on the "preferred band list". If UE is not able to find any cell during this search then it will switch the band list to the "non-preferred band list" and will start normal service search as well as limited service search as shown in the Fig-2. Whenever UE gained the service on a cell then UE will recalculate the "preferred band list" and "non-preferred band list" for better results as per the procedure mentioned in Fig-1. When UE is moved from in service to no service; UE need to do the search for recovery of service. Fig-3 depicts the searching for the service based on the first embodiment of invention as mentioned in Fig-1. In this case there is a more probability to get the service on "preferred band list" so; UE will do search for more times in the "preferred band list" than the "non preferred band list". In Fig-3 it shows that UE does the search on "preferred band list" for X times and one time in "non-preferred band list". During roaming case UE does the periodic search for high priority PLMN cells when it camped on a VPLMN in automatic mode. The Fig -4 flow chart shows the implementation in the UE when the High priority PLMN Search timer expires based on the first embodiment of invention as explained in Fig-1. It shows that High priority PLMN search will be restricted to the bands corresponds to "Preferred band list" for most of the times. In order to take care of a scenario where SE 13 table may not be updated (to take into consideration of latest band information) the UE initiates the high priority PLMN scan in other bands which UE is capable of once in 'N' times (value of (N' is implementation dependent). Fig-5 flow chart shows the second embodiment of invention which is maintaining an "extended SE.13 table" in non volatile memory and it as an extension to the usual SE.13 table. This table will be updated whenever UE come across a new PLMN, and band combination. Whenever UE camped on a cell then UE will check for the current camped cell information (PLMN, band) entry in SE.13 table. If this (PLMN, band) entry is not found then UE will add a new entry in "Extended SE.13 table". After this while calculating the preferred band list UE will refers the both tables which are SE.13 table and "Extended SE.13 table". Fig-6 flowchart is another embodiment of invention which is maintaining different preferred band lists for normal service cell search and limited service cell search. During registration procedure if forbidden PLMN list is changed or modified due to registration success or failure then UE will calculate the preferred band lists. In this embodiment maintains two preferred band lists. One is "Normal service preferred band list" which will be used to search for the normal service cells and the "limited service preferred band list" which will be used during the search for limited service cells. If a PLMN is added in to the FPLMN list and no other PLMN is exist in the same band for that MCC in SE.13 table then we can move that band to "limited service band list". So; that in future for normal service cell searches UE will not consider this band. Let's take the example - UE supports the bands GSM 900, GSM 1800, GSM 1900, GSM 850, and WCDMA2100. MCC 001 is having the bands GSM 900, GSM 1800, GSM 850 (refer the above mentioned SE. 13 table) Let's say UE is camped on a cell corresponding to the PLMN 001-030. The preferred band lists will be Normal service preferred band list - GSM 900, GSM 1800, GSM 850 Limited service preferred band list - GSM 900, GSM 1800, GSM 850 Non-preferred bands list - GSM 1900, WCDMA 2100 When UE tried the registration on 001-030 it got the registration reject from the network on 001-030 which caused the change in FPLMN list in SIM as shown in the above table. 001-030 is added in to FPLMN list. The band corresponds to the PLMN 001-030 is not having any other PLMN in SE.13 table in the MCC 001. So; this band will be removed from "normal service preferred band list". After recalculation of band lists: The preferred band lists will be Normal service preferred band list - GSM 900, GSM 850 Limited service preferred band list-GSM 900, GSM 1800, GSM 850 Non-preferred bands list - GSM 1900, WCDMA 2100 Figure 7 shows another embodiment of invention which is updating the network name in "extended SE.13 table" when UE receives an OTA message from network. After adding the entry in "extended SE.13 table" if UE receives a network name from network through OTA message then the same can be updated in to the table. Figure 8 shows the power on procedure by using preferred bands list. In automatic mode during power on UE will read the "preferred bands lists" from non volatile memory and derives the "normal service preferred bands list" "limited service preferred bands list" and non-preferred bands list by considering the forbidden PLMN list in SIM. When UE lost the service on current serving cell then UE should start doing the recovery search procedure for recovery. Fig-9 explains the procedure should be followed by UE to get in to service. UE will use "Normal service preferred band list" for normal service search and similarly it uses "limited service preferred band list" for limited service. Since; probability of getting the service on non-preferred band list is less so; one out of X times UE does the search on non-preferred bands list. The above procedure can be followed in the case of automatic band selection mode only. When UE camped on a VPLMN it need to do the periodic search for the high priority PLMN's in automatic mode. Fig -10 shows the high priority periodic search. During periodic HPLMN search UE will consider only the "normal service bands list". Once in X times UE can do the high priority search on "non-preferred band list". The "non-preferred band list" will be useful in the case of SE.13 list is not get updated to the latest. The main inventive concepts of the invention are: UE can use the SE 13 table to determine the band group to search for service per country, ie based on MCC. UE can divide the bands it is capable of operating into preferred band group and non preferred band group. - When UE looses coverage or at power on, UE looks for service in the preferred band for most of the time. Occasionally, UE will search for service in the non preferred bands. - Using the SE 13 table and the forbidden PLMN list, UE can optimize the preferred band by removing the band belonging to forbidden PLMN list from the preferred band group if the particular band is not being used by any other PLMN providing normal service in that country. - Updating the SE 13 table whenever the UE finds other band for the particular PLMN during occasional searches for non preferred understood as included within the scope of the present invention as defined by the appended claims unless they depart there from. band. Having a different preferred band groups for normal service scanning and limited service scanning. Normal service preferred band group will avoid bands from forbidden PLMN of a particular country where as limited service preferred band group will have the entire band for the corresponding PLMNs of a country based on SE 13 table. During high priority PLMN/HPLMN searches, UE can restrict to the bands of higher priority PLMN/HPLMN of a country based on SE 13 table. It will also be obvious to those skilled in the art that other control methods and apparatuses can be derived from the combinations of the various methods and apparatuses of the present invention as taught by the description and the accompanying drawings and these shall also be considered within the scope of the present invention. Further, description of such combinations and variations is therefore omitted above. It should also be noted that the host for storing the applications include but not limited to a microchip, microprocessor, handheld communication device, computer, rendering device or a multi function device. Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art. Such changes and modifications are to be WE CLAIM 1. A method of optimized band selection by a UE wherein the said UE uses a database to determine a band group to search for mobile service of a region based on MCC where the UE divides plurality of bands it is capable of operating into preferred band group and non preferred band group. 2. A method as claimed in claim 1, wherein the initial database used is SE 13 table released by GSM association periodically. 3. A method as claimed in claim 1, wherein in the absence of coverage or at power on, UE looks for mobile service in the preferred band for most of the time and occasionally, search for service in the non preferred band. 4. A method as claimed in claim 1, wherein using the database and a forbidden PLMN list, UE optimize the preferred band by removing the band belonging to forbidden PLMN list from the preferred band group if the particular band is not being used by any other PLMN providing normal service in the region. 5. A method as claimed in claim 1, wherein UE update the database whenever the UE finds other bands for the particular PLMN during occasional searches for non preferred bands. 6. A method as claimed in claim 5, wherein updation of database includes updating the elements like PLMN information, band information and PLMN name etc 7. A method as claimed in claim 1 wherein the UE maintains different preferred band groups for normal service scanning and limited service scanning. 8. A method as claimed in claim 7 wherein normal service preferred band group avoid bands from forbidden PLMN of a particular region where as limited service preferred band group have the entire band for the corresponding PLMNs of a region based on the database. 9. A method as claimed in claim 1 wherein during high priority PLMN searches, UE restrict to the bands of higher priority PLMN of a region based on the database. 10. A method of optimized band selection by a UE substantially described particularly with reference to the accompanying drawings.

Full Text

FIELD OF THE INVENTION
The present invention, in general, is related to a band selection method particular to a mobile communication system, which supports plurality of bands and may contain different communication access technologies. This invention is also related to using of a GSM association released SE.13 table, which consists of network code names, supported bands and other information. More particularly, the present invention relates to optimized method of band selection in a multi band GSM/3G mobile.
DESCRIPTION OF THE RELATED ART
A multi band/mode mobile communication system which supports multiple bands i.e. GSM 850, GSM 1900, GSM 900, GSM 1800, UMTS 850, UMTS 1900, and UMTS 2100 etc can be operated in any of the supported bands. When a UE is looking for the service on a network or a cell it should start scanning for all the frequencies corresponding to a frequency band to know the existence of the service in that particular band. There are several methods to get the service in a multi band mobile communication system. One method is scanning for all the bands to know the existence of a service. Another method is giving an option to the user to choose the particular bands and modes for the scanning. Some more existing methods says that maintaining a supported bands for each MCC in a non volatile memory and update the same when ever UE comes to know the

new band existence.
Whenever mobile station powered on OR lost the service on current cell then it should start searching for the cells to get service. One way of finding the service is searching for all the frequencies corresponding to supported bands by UE, but it will consume more power since that place may not be required to look for the service in all the UE supported bands. Saving the power of a Mobile station is a very important aspect with respect to user point of view. The second method is giving an option to the user for selecting the band and mode combinations on which UE should look for the service. The problem with this method is user should have good knowledge about the frequency of bands and modes existence at each geographical area to get the better results. Another method is selecting particular bands for each MCC out of all the UE supported bands by using a non-volatile memory table which consists of allocated bands corresponding to each country. This memory table will be updated whenever UE come across a new system and the band. Here the problem is non-volatile memory for which accessing speed increases.
GSM Congress will release a latest SE.13 table on every month; and it contains Country Initials, Organisation, Network, PPCI&N, Abrev. Net. Name, Net. Type (mode and band), MCC, MNC, NCC. Usually GSM mobiles which come to the market will contain the latest SE.13 table available at the time of release. None of the prior arts talks about the updating of SE.13 table when UE come across a new network.

As mentioned in the prior art UE will do search for two types of cells. One search is looking for normal service cells and another one is looking for the limited service cells. Initially UE will start searching for normal service cells through which user can get all subscribed services. If UE is not able to find a normal service cell then it will search for limited service cells by considering forbidden PLMN list and forbidden LAI list.
The invention is giving a method of a selection of proper bands by using a SE.13 table for a multi mode mobile communication device which supports multiple bands in GSM as well as UMTS. In Automatic band selection mode UE can prepare two type bands list which are "preferred band list" and "non-preferred band list". "Preferred band list" will be prepared based on the current MCC on which UE is camped by looking in to the SE.13 table list. SE.13 list will be stored in read only memory so; that accessing will be faster.
In the current method UE will store SE.13 table with the fields MCC, MNC, network name and network type (i.e. band, mode). Whenever UE camped on a cell it will come to know the PLMN id which is MCC, MNC. By using this MCC and SE.13 table; UE will derive the "preferred band list" which are allocated in that country by looking in to SE.13 table. The rest of the bands (which are not present in preferred bands list) will become a "non-preferred band list". Since then whenever UE looses the coverage on current cell it will start scanning on all the frequencies corresponding to the bands of "preferred band list". Additionally,

periodically may be one out of X times, UE will do search on "non preferred band list".
On power off UE will store the "preferred band list" in to non volatile memory and the same will be used on next power on. In the current proposed method on power on situation first UE will do search on all the frequencies corresponding to "preferred band list". If it is not able to find the service then UE will do the search on all the frequencies corresponding to "non-preferred band list". Once UE finds a cell corresponds to some band then UE will make use of MCC, MNC of that cell and SE. 13 table to derive new "preferred band list".
According to GSM congress the SE.13 table will be updated on every month. In the proposed method UE is going to maintain "extension of SE.13 list" in nonvolatile memory. During preferred band search or non-preferred band search if UE come across a new cell who's MCC, MNC are not present in the SE.13 table then UE will add an entry to the "extension of SE.13 list" and same can be used for further derivations of band list. If UE comes to know the network name of this MCC, MNC through OTA message then the same name can be updated in "extension of SE.13 list". "Extension of SE.13 list" will contain Net. Name, Net. Type (mode and band), MCC, MNC.
In the proposed method while deriving the preferred band list UE will also considers the forbidden PLMN list which will be present in the SIM. During normal service search the bands corresponding to forbidden PLMN's can be

removed from the preferred band list, provided if there are no other PLMN's exist on that particular band in that country. For limited service search we need to consider a different preferred band list.
The concept of using MCC, MNC information to determine which bands need to be searched for service has been identified in patent applications US 2006/0194577 and US 2007/0004405. Patent application US 2006/0194577 also mentions storing a set of preferred bands in the user equipment. Further, US 2006/0194577 also seems to disclose the concept of searching for service in 'preferred band' first and for service in 'non-preferred band' occasionally. Updating MCC, MNC information is also mentioned in US 2006/0194577.
SUMMARY OF THE INVENTION
The present invention relates to the field of mobile communication system. In particular, the invention proposes a method for selecting a band by using a SE.13 table for a multi-mode user equipment (UE) which supports multiple bands in GSM and UMTS. According to the method, a UE stores a SE.13 table having the fields Mobile Country Code (MCC), Mobile Network Code (MNC), network name and network type. Whenever the UE camps on a cell, it finds out its PLMN ID (i.e. MCC, MNC) from the broad cast information of the cell. The UE then uses the SE.13 table to derive a 'preferred band list' which are allocated in that country. The rest of the bands i.e. the bands which are not present in the 'preferred band list', become a part of a 'non-preferred band list'. The UE stores

the 'preferred band list' in a non-volatile memory while powering off and uses the list when it is powered on. Now whenever the UE is powered on or loses coverage on a cell, it first scans all the frequencies present in the 'preferred band list'. In addition, the UE scans the frequencies present in the 'non-preferred band list1, one out of X times. The UE will also consider forbidden PLMN list (present in the SIM card) while deriving the preferred band list. The UE has different band groups for 'normal service' scanning and for 'limited service' scanning.
Further, the UE also maintains an 'extended SE.13 table' in a non-volatile memory. During the preferred band search or the non-preferred band search, if the UE comes across a new cell which is not present in the SE.13 table, the UE will add this entry to the 'extended SE.13 table'.
Accordingly the invention explains a method of optimized band selection by a UE wherein the said UE uses a database to determine a band group to search for mobile service of a region based on MCC where the UE divides plurality of bands it is capable of operating into preferred band group and non preferred band group.
The absence of coverage or at power on, UE looks for mobile service in the preferred band for most of the time and occasionally, search for service in the non preferred band. Using the database and a forbidden PLMN list, UE optimize the preferred band by removing the band belonging to forbidden PLMN list from the preferred band group if the particular band is not being used by any other

PLMN providing normal service in the region. UE update the database whenever the UE finds other bands for the particular PLMN during occasional searches for non preferred bands. The UE maintains different preferred band groups for normal service scanning and limited service scanning. Normal service preferred band group avoid bands from forbidden PLMN of a particular region where as limited service preferred band group have the entire band for the corresponding PLMNs of a region based on the database. During high priority PLMN searches, UE restrict to the bands of higher priority PLMN of a region based on the database.
These and other objects, features and advantages of the present invention will become more apparent from the ensuing detailed description of the invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 depicts the first embodiment of invention
Figure 2 shows the searching for the service on power-on by UE based on the first embodiment of invention
Figure 3 depicts the searching for the service during recovery from lack of coverage based on the first embodiment of invention

Figure 4 depicts a flow chart shows the implementation in the UE when the High priority PLMN Search timer expires based on the first embodiment of invention
Figure 5 depicts a flow chart shows the second embodiment of invention; which is maintaining the extended SE-13 table.
Figure 6 depicts a flowchart is another embodiment of invention which is maintaining different preferred band lists for normal service cell search and limited service cell search
Figure 7 shows another embodiment of invention which is updating the network name in "extended SE.13 table" when UE receives an OTA message from network
Figure 8 shows the power on procedure by using different preferred bands list for normal service and limited services.
Figure 9 explains the procedure should be followed by UE to get in to service with including all above embodiments.
Figure 10 shows the high priority periodic PLMN search by including all the above embodiments.

DETAILED DESCRIPTION OF THE INVENTION
The preferred embodiments of the present invention will now be explained with reference to the accompanying drawings. It should be understood however that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. The following description and drawings are not to be construed as limiting the invention and numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However in certain instances, well-known or conventional details are not described in order not to unnecessarily obscure the present invention in detail.
Figure 1 shows the calculation of "preferred band list" and "non preferred band list" based on the MCC of the current camped cell using SE.13 table. Whenever UE camped on a cell then UE will read the MCC (which will be broadcasted by radio network) of the current camped cell and check with SE.13 table for corresponding entry. Based on this MCC entry in SE.13 table UE will calculate the "preferred band list" and "non preferred band list".
If this MCC entry is present in SE.13 table then "Preferred band list" is equal to the all bands which are corresponds to this particular MCC in the SE.13 table. Remaining all supported bands by UE will be kept in "non preferred band list".

If this MCC entry is not present in SE.13 table then "Preferred band list" is equal to the band of the current camped cell and "non preferred band list" is equal to the all the remaining bands supported by UE.
The above calculated band lists will be used accordingly by the UE; for the normal service search and limited service search. During power off UE can store "Preferred band list" in non-volatile memory and the same can be used for the next power on.
Figure 2 shows the searching for the service during power-on by UE based on the first embodiment of invention. During power on UE will read the "preferred band list" which was stored in NV and the same will be used for the search. First UE will do the normal service search and limited service search on the "preferred band list". If UE is not able to find any cell during this search then it will switch the band list to the "non-preferred band list" and will start normal service search as well as limited service search as shown in the Fig-2. Whenever UE gained the service on a cell then UE will recalculate the "preferred band list" and "non-preferred band list" for better results as per the procedure mentioned in Fig-1.
When UE is moved from in service to no service; UE need to do the search for recovery of service. Fig-3 depicts the searching for the service based on the first embodiment of invention as mentioned in Fig-1. In this case there is a more probability to get the service on "preferred band list" so; UE will do search for more times in the "preferred band list" than the "non preferred band list". In Fig-3

it shows that UE does the search on "preferred band list" for X times and one time in "non-preferred band list".
During roaming case UE does the periodic search for high priority PLMN cells when it camped on a VPLMN in automatic mode. The Fig -4 flow chart shows the implementation in the UE when the High priority PLMN Search timer expires based on the first embodiment of invention as explained in Fig-1. It shows that High priority PLMN search will be restricted to the bands corresponds to "Preferred band list" for most of the times.
In order to take care of a scenario where SE 13 table may not be updated (to take into consideration of latest band information) the UE initiates the high priority PLMN scan in other bands which UE is capable of once in 'N' times (value of (N' is implementation dependent).
Fig-5 flow chart shows the second embodiment of invention which is maintaining an "extended SE.13 table" in non volatile memory and it as an extension to the usual SE.13 table. This table will be updated whenever UE come across a new PLMN, and band combination.
Whenever UE camped on a cell then UE will check for the current camped cell information (PLMN, band) entry in SE.13 table. If this (PLMN, band) entry is not found then UE will add a new entry in "Extended SE.13 table". After this while calculating the preferred band list UE will refers the both tables which are SE.13

table and "Extended SE.13 table".
Fig-6 flowchart is another embodiment of invention which is maintaining different preferred band lists for normal service cell search and limited service cell search. During registration procedure if forbidden PLMN list is changed or modified due to registration success or failure then UE will calculate the preferred band lists. In this embodiment maintains two preferred band lists. One is "Normal service preferred band list" which will be used to search for the normal service cells and the "limited service preferred band list" which will be used during the search for limited service cells.
If a PLMN is added in to the FPLMN list and no other PLMN is exist in the same band for that MCC in SE.13 table then we can move that band to "limited service band list". So; that in future for normal service cell searches UE will not consider this band.

Let's take the example -
UE supports the bands GSM 900, GSM 1800, GSM 1900, GSM 850, and
WCDMA2100.
MCC 001 is having the bands GSM 900, GSM 1800, GSM 850 (refer the above
mentioned SE. 13 table)
Let's say UE is camped on a cell corresponding to the PLMN 001-030.
The preferred band lists will be
Normal service preferred band list - GSM 900, GSM 1800, GSM 850 Limited service preferred band list - GSM 900, GSM 1800, GSM 850 Non-preferred bands list - GSM 1900, WCDMA 2100
When UE tried the registration on 001-030 it got the registration reject from the network on 001-030 which caused the change in FPLMN list in SIM as shown in the above table. 001-030 is added in to FPLMN list. The band corresponds to the PLMN 001-030 is not having any other PLMN in SE.13 table in the MCC 001. So; this band will be removed from "normal service preferred band list". After recalculation of band lists:
The preferred band lists will be
Normal service preferred band list - GSM 900, GSM 850

Limited service preferred band list-GSM 900, GSM 1800, GSM 850 Non-preferred bands list - GSM 1900, WCDMA 2100
Figure 7 shows another embodiment of invention which is updating the network name in "extended SE.13 table" when UE receives an OTA message from network. After adding the entry in "extended SE.13 table" if UE receives a network name from network through OTA message then the same can be updated in to the table.
Figure 8 shows the power on procedure by using preferred bands list. In automatic mode during power on UE will read the "preferred bands lists" from non volatile memory and derives the "normal service preferred bands list" "limited service preferred bands list" and non-preferred bands list by considering the forbidden PLMN list in SIM.
When UE lost the service on current serving cell then UE should start doing the recovery search procedure for recovery. Fig-9 explains the procedure should be followed by UE to get in to service. UE will use "Normal service preferred band list" for normal service search and similarly it uses "limited service preferred band list" for limited service. Since; probability of getting the service on non-preferred band list is less so; one out of X times UE does the search on non-preferred bands list. The above procedure can be followed in the case of automatic band selection mode only.

When UE camped on a VPLMN it need to do the periodic search for the high priority PLMN's in automatic mode. Fig -10 shows the high priority periodic search. During periodic HPLMN search UE will consider only the "normal service bands list". Once in X times UE can do the high priority search on "non-preferred band list". The "non-preferred band list" will be useful in the case of SE.13 list is not get updated to the latest.
The main inventive concepts of the invention are:
UE can use the SE 13 table to determine the band group to search for service per country, ie based on MCC. UE can divide the bands it is capable of operating into preferred band group and non preferred band group.
- When UE looses coverage or at power on, UE looks for service in the preferred band for most of the time. Occasionally, UE will search for service in the non preferred bands.
- Using the SE 13 table and the forbidden PLMN list, UE can optimize the preferred band by removing the band belonging to forbidden PLMN list from the preferred band group if the particular band is not being used by any other PLMN providing normal service in that country.
- Updating the SE 13 table whenever the UE finds other band for the particular PLMN during occasional searches for non preferred

understood as included within the scope of the present invention as defined by the appended claims unless they depart there from.

band.
Having a different preferred band groups for normal service scanning and limited service scanning. Normal service preferred band group will avoid bands from forbidden PLMN of a particular country where as limited service preferred band group will have the entire band for the corresponding PLMNs of a country based on SE 13 table.
During high priority PLMN/HPLMN searches, UE can restrict to the bands of higher priority PLMN/HPLMN of a country based on SE 13 table.
It will also be obvious to those skilled in the art that other control methods and apparatuses can be derived from the combinations of the various methods and apparatuses of the present invention as taught by the description and the accompanying drawings and these shall also be considered within the scope of the present invention. Further, description of such combinations and variations is therefore omitted above. It should also be noted that the host for storing the applications include but not limited to a microchip, microprocessor, handheld communication device, computer, rendering device or a multi function device.
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art. Such changes and modifications are to be

WE CLAIM
1. A method of optimized band selection by a UE wherein the said UE uses a database to determine a band group to search for mobile service of a region based on MCC where the UE divides plurality of bands it is capable of operating into preferred band group and non preferred band group.
2. A method as claimed in claim 1, wherein the initial database used is SE 13 table released by GSM association periodically.

3. A method as claimed in claim 1, wherein in the absence of coverage or at power on, UE looks for mobile service in the preferred band for most of the time and occasionally, search for service in the non preferred band.
4. A method as claimed in claim 1, wherein using the database and a forbidden PLMN list, UE optimize the preferred band by removing the band belonging to forbidden PLMN list from the preferred band group if the particular band is not being used by any other PLMN providing normal service in the region.
5. A method as claimed in claim 1, wherein UE update the database whenever the UE finds other bands for the particular PLMN during occasional searches for non preferred bands.

6. A method as claimed in claim 5, wherein updation of database includes
updating the elements like PLMN information, band information and PLMN name
etc
7. A method as claimed in claim 1 wherein the UE maintains different preferred
band groups for normal service scanning and limited service scanning.
8. A method as claimed in claim 7 wherein normal service preferred band group
avoid bands from forbidden PLMN of a particular region where as limited service
preferred band group have the entire band for the corresponding PLMNs of a
region based on the database.
9. A method as claimed in claim 1 wherein during high priority PLMN searches,
UE restrict to the bands of higher priority PLMN of a region based on the
database.
10. A method of optimized band selection by a UE substantially described
particularly with reference to the accompanying drawings.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=qGPXBgeh6AJAHj5Wqdm4MA==&loc=egcICQiyoj82NGgGrC5ChA==

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Patent Number

271300

Indian Patent Application Number

2333/CHE/2007

PG Journal Number

08/2016

Publication Date

19-Feb-2016

Grant Date

15-Feb-2016

Date of Filing

15-Oct-2007

Name of Patentee

SAMSUNG R&D INSTITUTE INDIA-BANGALORE PRIVATE LIMITED

Applicant Address

#2870 ORION BUILDING BAGMANE CONSTELLATION BUSINESS PARK OUTER RING ROAD DODDANEKUNDI CIRCLE MARATHAHALLI POST BANGALORE 560037

Inventors:

#	Inventor's Name	Inventor's Address
1	SESHAGIRI R GORANTLA	EMPLOYED AT SAMSUNG INDIA SOFTWARE OPERATIONS PRIVATE LIMITED BAGMANE LAKEVIEW BLOCK 'B' NO 66/1 BAGMANE TECH PARK C V RAMAN NAGAR BYRASANDRA BANGALORE 560093
2	LAKSHMI NARAYANA KAVURI	EMPLOYED AT SAMSUNG INDIA SOFTWARE OPERATIONS PRIVATE LIMITED BAGMANE LAKEVIEW BLOCK 'B' NO 66/1 BAGMANE TECH PARK C V RAMAN NAGAR BYRASANDRA BANGALORE 560093
3	PRAKASH RAO	EMPLOYED AT SAMSUNG INDIA SOFTWARE OPERATIONS PRIVATE LIMITED BAGMANE LAKEVIEW BLOCK 'B' NO 66/1 BAGMANE TECH PARK C V RAMAN NAGAR BYRASANDRA BANGALORE 560093

PCT International Classification Number

H04B 7/26

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA