Method, user equipment, system or mobile communication network, program and computer program product for realizing network selection by a user equipment in a radio environment comprising multiple radio cells of multiple mobile communication networks - Patents.com

Abstract

The present invention relates to a method for realizing network selection by a user equipment in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, characterized in that in a first step, suitable radio cells of the considered radio access technologies are determined by the user equipment based on the cell selection criteria for the considered radio access technologies, and in a second step, upon initiating network selection according to the automatic network selection mode, only those mobile communication networks corresponding to suitable radio cells of the considered radio access technologies are considered for network selection of the user equipment which have reception conditions that correspond to or exceed the extended network selection criteria.

Description

[Background technology]

[0001] The present invention relates to a method for realizing network selection by a user equipment in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of which is associated respectively with at least one mobile communication network of the plurality of mobile communication networks, the user equipment measuring or detecting reception conditions for the plurality of radio cells and thereafter selecting and / or registering with a mobile communication network from among the plurality of mobile communication networks.

[0002] Furthermore, the present invention relates to a user equipment for realizing network selection by a user equipment in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of said radio cells being respectively associated with at least one mobile communication network of the plurality of mobile communication networks, the user equipment being configured to measure or detect reception conditions for the plurality of radio cells and subsequently configured to select and / or register with a mobile communication network from the plurality of mobile communication networks.

[0003] Additionally, the present invention relates to a system or a mobile communication network for realizing network selection by a user equipment in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of which is associated respectively with at least one mobile communication network of the plurality of mobile communication networks, the user equipment being configured to measure or detect reception conditions for the plurality of radio cells and thereafter to select and / or register with a mobile communication network from the plurality of mobile communication networks.

[0004] Furthermore, the present invention relates to a program and a computer readable medium for implementing network selection by a user equipment in a radio environment comprising multiple radio cells of multiple mobile communication networks according to the method of the present invention.

[0005] In currently deployed mobile communication networks, a user equipment or mobile station typically experiences a radio environment comprising multiple radio cells (i.e., different radio frequency signals that a user equipment can potentially receive at its current position or location, at different frequencies and / or frequency bands and / or at different times or time intervals or time slots) that are at least detectable and / or receivable by the respective user equipment or mobile station. One such radio cell is typically provided by a base station entity, i.e., an antenna arrangement of a particular base station entity emits radio frequency signals such that a user equipment can receive such radio frequency signals at its current position or location with sufficient quality, typically with a sufficient signal-to-noise ratio. In this case, the radio environment of the user equipment comprises the considered radio cell. The multiple radio cells (i.e., multiple base station entities) are typically part of a mobile communication network, which is a cellular mobile communication network. Thus, the multiple radio cells of the radio environment of the user equipment are typically part of multiple mobile communication networks, and typically each of these radio cells is associated with either one of the multiple mobile communication networks or multiple mobile communication networks of the multiple mobile communication networks, respectively. Thus, by selecting a radio cell (from the multiple radio cells that are present or can receive the radio environment at the considered position or location of the user equipment), the user equipment also selects a mobile communication network (associated with that radio cell). However, before a mobile communication network is considered as a network selection candidate (i.e., a candidate mobile communication network), the user equipment needs to find a suitable radio cell of the mobile communication network or public land mobile network to camp on. The criteria for a radio cell to be considered as a suitable radio cell (to camp on) depend on the considered network technology (or radio access technology) and are defined in or with the relevant standardization documents, mainly 3GPP (3rd Generation Partnership Project) documents.

[0006] In currently known mobile communication networks, i.e. networks that comply with currently defined standards or standard documents, some drawbacks may occur: in bad or unfavorable radio coverage situations (of user equipment), the order or prioritization defined by 3GPP of how mobile communication networks are selected to obtain a communication service or any service is not appropriate in all relevant situations. For example, in some situations, the field strength or field quality (of a radio signal or multiple radio signals) of a radio cell (of the radio environment of the user equipment) is not taken into account in the network selection process (PLMN selection process), leading to the user equipment being unable to receive and / or transmit data after the initial network selection process (PLMN selection process). Such situations include cases where some user equipment may fail to obtain a data service, even if the selected public land mobile network fulfills the cell selection criteria for considering the respective mobile communication network (public land mobile network) in the network selection (or PLMN selection) process. In particular, when the user equipment is in an unfavorable or undesirable location, the applicable cell selection criteria (e.g., "RX Access Lev min") are rarely met, allowing the user equipment to consider the respective public land mobile network for PLMN selection, but in reality, for example due to fading or local interference at the user equipment's location, data transmission between the network and the user equipment may then fail. Such cases arise especially for cellular user equipment or devices for Internet of Things or M2M (machine-to-machine) communication services, where the devices are often used in a stationary manner (e.g., being meters or all kinds of sensors, etc.), and in case of unfavorable radio (reception) conditions, this kind of problem is likely to persist for such user equipment, leading to a situation where such user equipment (especially when in automatic network selection mode) is stuck on a PLMN but cannot transmit data.In the absence of advanced application logic, such user equipment may currently require manual intervention in the field, since it is no longer reachable as well; therefore, such user equipment may need to be switched or reconfigured into a manual network selection (PLMN selection) mode and a suitable mobile communication network may need to be permanently selected, which may lead to further difficulties in selecting a suitable mobile communication network in case of network modifications and / or local modifications of the respective base station entities involved. Such interventions may be costly for the user of such user equipment (especially, but not necessarily, Internet of Things devices), and the use of a manual network selection mode may provide the advantages of automatic network selection, e.g., reselection to another mobile communication network in case of an outage of the registered network (Registered Public Land Mobile Network, RPLMN), which cannot be realized any more. Summary of the Invention

[0007] It is an object of the present invention to provide a technically simple, efficient and cost-effective solution for enhanced network selection by a user equipment in a radio environment comprising multiple radio cells of multiple mobile communication networks. It is a further object of the present invention to provide a corresponding user equipment, a system or a mobile communication network and a corresponding program and computer readable medium.

[0008] The object of the invention is achieved by a method for realizing network selection by a user equipment in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of these radio cells being respectively associated with at least one of the plurality of mobile communication networks, the user equipment measuring or detecting reception conditions for the plurality of radio cells and subsequently selecting and / or registering with a mobile communication network from among the plurality of mobile communication networks, cell selection criteria being defined for the cell selection by the user equipment, and a radio cell of the considered radio access technology being selected if the corresponding reception conditions measured by the user equipment correspond to or exceed the cell selection criterion for the considered radio access technology. In this case, a radio cell is considered to be suitable and a predetermined extended network selection criterion can be applied for network selection by the user equipment, the method comprising the following steps: in a first step, suitable radio cells of the considered radio access technology are determined by the user equipment based on the cell selection criterion for the considered radio access technology, and in a second step, when starting network selection according to the automatic network selection mode, only such mobile communication networks which correspond to suitable radio cells of the considered radio access technology are considered for network selection of the user equipment which have reception conditions which correspond to or exceed the extended network selection criterion or which correspond to it.

[0009] Therefore, according to the invention, by being able to apply predefined extended network selection criteria (i.e. taking into account all suitable radio cells or their corresponding mobile communication networks) instead of applying the conventionally used processes, it is advantageously possible that the network selection can be performed in an optimized manner, in particular leading to avoiding the problems associated with the use of the conventionally used network selection processes as described above.

[0010] Conventionally, cell selection criteria are used for suitable radio cells to be considered (i.e. for the user equipment to camp on), and these cell selection criteria typically depend on the considered network technology (or radio access technology) used, i.e. the radio access technology that both the user equipment and the radio cell are using. Typically, different generations of mobile communication systems (i.e. different radio access technologies) are considered, most frequently including one, all or a subset of the following: 2G, 3G, 4G and 5G technologies (i.e. second generation mobile communication systems (GSM, Global System for Mobile Communications), third generation mobile communication systems (UMTS, Universal Mobile Telecommunications System including its radio technology E-UTRA, Evolved UMTS Terrestrial Radio Access), fourth generation mobile communication systems (LTE, Long Term Evolution including its radio technology E-UTRA, Evolved UMTS Terrestrial Radio Access), fifth generation mobile communication systems (5GS, 5G systems including its radio technology, NR, New Radio)), although further or additional or alternative radio access technologies are not excluded according to the present invention.

[0011] In the following, conventionally used cell selection criteria (or cell selection criteria) are provided according to the different, currently most frequently deployed radio access technologies: GSM networks: for GSM networks, the criteria for accessing or camping on a radio cell are given, inter alia, in 3GPP TS 43.022 “Functions related to Mobile Station (MS) in idle mode and group receive mode”, in particular in version V16.0.0 (2020-07), Section 3.6; The parameter RXLEV_ACCESS_MIN is broadcast as system information and relates to the minimum signal that the operator wants the network to receive when first accessed by an MS. UTRA networks: For UTRA networks, the criteria for accessing or camping on a cell are given, inter alia, in 3GPP TS 25.304 “User Equipment (UE) procedures in idle mode and procedures for cell reselection in connected mode”, in particular in version V16.0.0 (2020-07), Section 5.2.3.1.2; the cell selection criterion S is met when, for FDD cells, Srxlev>0 and Squal>0, and for TDD cells, Srxlev>0, where: Squal=Q qualmeas -(Qqualmin QqualminOffset)-Qoffset temp and Srxlev=Q rxlevmeas -(Qrxlevmin QrxlevminOffset)-Pcompensation-Qoffset temp and Here, the signaled values ​​QqualminOffset and QrxlevminOffset apply only when the cell is evaluated for cell selection as a result of a periodic search for higher priority PLMNs while successfully camped on a VPLMN (Visited Public Land Mobile Network). LTE and NB-IoT Networks / E-UTRA Networks: For LTE and NB-IoT networks, the standards for accessing or camping on a cell are specifically 3GPP TS36.304 "User Equipment (UE) procedures in idle mode" Specifically given in version V16.1.0 (2020-07), Section 5.2.3.2 and 5.2.3.2a: LTE cell selection criteria: A cell selection criterion S in normal coverage is met if Srxlev>0 and Squal>0; Srxlev=Qrxlevmeas-(Qrxlevmin Qrxlevminoffset)-Pcompensation-Qoffsettemp Squal=Qqualmeas-(Qqualmin Qqualminoffset)-Qoffsettemp Cell selection criteria for NB-IoT: If measurements are performed on non-anchor carriers and the UE meets the requirements specified in TS 36.133, then the cell selection criterion S is met if Srxlev>0, otherwise the cell selection criterion S is met if Srxlev>0 and Squal>0: Srxlev=Qrxlevmeas-Qrxlevmin-Pcompensation-Qoffsettemp Squal=Qqualmeas-Qqualmin-Qoffsettemp NR network: For NR networks, the criteria for accessing or camping on a cell are given in particular in 3GPP TS 38.304 “User Equipment (UE) procedures in Idle mode and RRC Inactive state”, in particular in version V16.1.0 (2020-07), Section 5.2.3.2; the cell selection criterion S is met if Srxlev>0 and Squal>0: Srxlev=Qrxlevmeas-(Qrxlevmin Qrxlevminoffset)-Pcompensation-Qoffsettemp Squal=Qqualmeas-(Qqualmin Qqualminoffset)-Qoffsettemp

[0012] Once the user equipment (or, more specifically, the so-called Access Stratum (AS) part of the user equipment) has read one or several PLMNs, i.e. one or several radio cells, which may belong to different mobile communication networks or public land mobile networks, the radio cells or public land mobile networks which pass the cell selection criteria (applied respectively taking into account potentially different radio access technologies) are reported to the so-called Non-Access Stratum (NAS) (or the NAS part of the user equipment) for a subsequent stage (or step) of network selection. Typically, this reporting also includes the transmission of the respective field strength values ​​(measured by the user equipment), such as for example the Reference Signal Received Power (RERP) values. Typically, according to the conventionally known and used standardized user equipment behavior, the respective field strength values ​​(measured by the user equipment) are not reported to the NAS for radio cells which not only satisfy the cell selection criterion (respectively applying with respect to the radio access technology considered), but also satisfy the so-called high quality criterion; however, also for such high quality radio cells the AS indicates their high quality characteristics (or the fact that these radio cells are measured as satisfying the high quality criterion) to the NAS and therefore, at least implicitly, also transmits the field strength values ​​for these radio cells.

[0013] In the following, the conventionally used high quality criterion (or criterions) are provided according to the different, currently most frequently deployed radio access technologies: GSM: For GSM, the high quality criterion is given in 3GPP TS 43.022 “Functions related to Mobile Station (MS) in idle mode and group receive mode”, in particular in version V16.0.0 (2020-07), Section 4.4.3, as follows: It should be understood that a PLMN is received with a high quality signal if the signal level is above -85 dBm. UTRAN: For UTRA, the high quality criteria are given in 3GPP TS 25.304 "User Equipment (UE) procedures in idle mode and procedures for cell reselection in connected mode", in particular version V16.0.0 (2020-07), Section 5.1.2.2, and are as follows: for FDD cells, the measured Primary CPICH RSCP value shall be equal to or greater than -95 dBm; for TDD cells, the measured P-CCPCH RSCP shall be equal to or greater than -84 dBm. For E-UTRAN:LTE / NB-IoT, the high quality criteria are given in 3GPP TS 36.304 "User Equipment (UE) procedures in idle mode", in particular version V16.1.0 (2020-07), Section 5.1.2.2: For E-UTRAN and NB-IoT cells, the measured RSRP value shall be greater than or equal to -110 dBm. NR: For NR, the high quality criteria are given in 3GPP TS 38.304 “User Equipment (UE) procedures in Idle mode and RRC Inactive state”, in particular version V16.1.0 (2020-07), Section 5.1.1.2, and are as follows: For NR cells, the measured RSRP value shall be greater than or equal to -110 dBm.

[0014] Based on the reports (in particular from the AS part of the user equipment to the NAS part of the user equipment) the actual network selection can be performed. Conventionally, in the network selection phase, all radio cells that were determined to be suitable (in a previous cell selection phase) are taken into account.

[0015] Simply put, at switch-on or recovery from lack of coverage, either the last registered PLMN or an equivalent PLMN (to the last registered PLMN), or alternatively either the home public land mobile network (HPLMN) or the highest priority equivalent home public land mobile network (EHPLMN) available, as an option configured on the user equipment's Subscriber Identity Module (SIM), is selected. With regard to reselection, the simplified order of network selection is as follows: i) Either the HPLMN or the highest priority EHPLMN available; ii) each PLMN / access technology combination (in order of priority) in a "User-controlled PLMN selector with access technologies" data file in the SIM; iii) each PLMN / access technology combination is stored in an "operator controlled PLMN selector with access technology" data file in the SIM (in priority order) or in the user equipment (in priority order); iv) other PLMNs / access technologies combine the received "high quality" signals in a random order; v) Other PLMN / access technology combinations are made in order of decreasing signal quality.

[0016] More specifically, the selection of a (mobile communication) network in the automatic network selection mode (from among the radio cells reported as receivable by the user equipment with sufficient signal strength) is defined depending on the actual state of the user equipment, in particular whether the user equipment has been switched on or has recovered from a lack of coverage or whether a reselection has been triggered by the (user equipment) user, as provided below. At switch-on or when recovering from lack of coverage, the user equipment or mobile station selects the registered PLMN (RPLMN) or equivalent PLMN, i.e. ERPLMN. As an alternative to this, if the user equipment or mobile station is in automatic network selection mode and finds coverage of an EHPLMN (HPLMN or equivalent PLMN), the user equipment or mobile station may register to that EHPLMN and not return to the registered PLMN or equivalent PLMN. The operator (of the user equipment's HPLMN) must be able to control, by SIM configuration, whether a user equipment or mobile station supporting this option is allowed to perform this alternative behavior. If the above network selection attempts are unsuccessful, the user equipment or mobile station shall select and attempt to register on other PLMN / access technology combinations, if available and permissible, in the following order: i) either the HPLMN (if the EHPLMN list does not exist or is empty) or the highest priority EHPLMN available (if an EHPLMN list exists); ii) each PLMN / access technology combination (in order of priority) in the "User-controlled PLMN selector with access technology" data file in the SIM; iii) Each PLMN / access technology combination is stored in the SIM (priority) or ME (priority) in the "Operator-controlled PLMN selector with access technology" data file; iv) other PLMNs / access technologies combine the received high quality signals in a random order; v) Other PLMN / access technology combinations are made in order of decreasing signal quality. User-triggered reselection: At any time, the user may request the user equipment or mobile station to initiate reselection and registration to an available PLMN according to the following procedure: In automatic network selection mode, the MS will select and attempt registration to a PLMN / access technology combination in all of its bands of operation, if available and permissible, according to the following order: i) the HPLMN (if the EHPLMN list does not exist or is empty) or the highest priority EHPLMN available (if an EHPLMN list exists); ii) the PLMN / access technology combinations contained (in order of priority) in the "User-controlled PLMN selector with access technologies" data file in the SIM, excluding any previously selected PLMN / access technology combinations; iii) the PLMN / access technology combinations (in priority order) contained in the "Operator-controlled PLMN selector with access technology" data file in the SIM or stored in the user equipment to the exclusion of previously selected PLMN / access technology combinations (in priority order); iv) other PLMN / access technology combinations have high quality signals received in random order except for the previously selected PLMN / access technology combination; v) other PLMN / access technology combinations excluding previously selected PLMN / access technology combinations in the order of decreasing signal quality, or alternatively, previously selected PLMN / access technology combinations may be selected without regard for their signal quality; vi) The previously selected PLMN / access technology combination. If the user equipment is in a visited public land mobile network (VPLMN), the user equipment or mobile station periodically attempts to acquire service on its HPLMN (if the EHPLMN list does not exist or is empty) or one of its EHPLMNs (if an EHPLMN list exists) or higher priority PLMN / access technology combinations listed in the "user-controlled PLMN selector" or "operator-controlled PLMN selector" by scanning according to the applicable requirements in i), ii) and iii) as defined above for the situation "at switch-on or recovery from lack of coverage". If the user equipment or mobile station has a stored "equivalent PLMN" list, the user equipment will select a PLMN only if it is of higher priority than a PLMN of the same country as the current serving PLMN stored in the "equivalent PLMN" list.

[0017] Thus, in conventional mobile communication networks, the commonly applied or performed (mobile communication) network selection behavior as defined in 3GPP standardization documents has the drawback that after a radio cell (or a corresponding public land mobile network) has passed the cell selection criterion (or criteria) as indicated above, a mobile communication network is selected (at the network selection stage) based only on a "non-field strength or quality based" criterion. This is typically the root cause of the above-mentioned problems and drawbacks of the currently applied steps of both cell selection and network selection (especially at switch-on or recovery from coverage shortage), i.e., the considered user equipment can only simply register (in a radio cell because the applicable cell selection criterion is met) but subsequently fails to actually transmit data, since such user equipment may be in a relatively bad or unfavorable coverage situation, e.g. experiencing fading or local interference at the user equipment's location. Thus, such user equipment remains stuck in the selected mobile communication network by applying the above-mentioned conventionally known procedure, despite the availability of other (mobile communication) networks with better conditions (or capable of providing an improved service quality).

[0018] According to the invention it is proposed that for network selection by the user equipment, predefined extended network selection criteria can be applied, i.e. such predefined extended network selection criteria are defined and used by the user equipment (or mobile station) when performing network selection (in particular according to an automatic network selection mode), so that at least initially for network selection purposes of the user equipment it takes into account only those mobile communication networks (corresponding to suitable cells of the considered radio access technology) which have or correspond to reception conditions which correspond to or exceed the extended network selection criteria.

[0019] This means that, according to the invention, conventionally known criteria for cell selection can be applied (including reporting such suitable radio cells (and corresponding public land mobile networks) to the NAS); however, of all such reported suitable radio cells, only a subset is, at least initially, considered for network selection purposes (i.e. the subset satisfies the extended network selection criteria).

[0020] Typically, applying the extended network selection criterion according to the invention in a network selection process (i.e. the proposed modification to apply to currently known and used network selection processes) has the effect, at least initially, of considering only suitable radio cells that correspond to or exceed the extended network selection criterion, i.e. having a better signal level (as measured by the user equipment), e.g. a higher level of received radio signal strength or field strength, and possibly a smaller number of radio cells and corresponding public land mobile networks are initially considered in the network selection phase (compared to the situation of a user equipment applying conventionally known network selection). However, with regard to such a possibly reduced number of selectable public land mobile networks (or mobile communication networks) that satisfy the extended network selection criterion, the user equipment is more likely not only to be able to register in these radio cells but also to actually transmit data (payload) according to the intended application for which the user equipment is used. Thus, according to the invention, in a first step the user equipment determines suitable radio cells (of the considered radio access technology) on the basis of a (conventionally known) cell selection criterion for the considered radio access technology, and in a second step only those mobile communication networks (corresponding to suitable radio cells of the considered radio access technology) determined during the network selection phase (in particular according to the automatic network selection mode) are (at least initially) considered for network selection of the user equipment which have or correspond to reception conditions which correspond to or exceed the extended network selection criterion.

[0021] According to the invention, it is advantageously possible and preferably possible for the extended network selection criteria to correspond to high quality criteria, which correspond to: For the Global System for Mobile Communications (GSM) as radio access technology: signal levels related to high quality reception of public land mobile networks according to 3GPP standardization: for the UMTS Terrestrial Radio Access Network (UTRAN), Evolved UMTS Terrestrial Radio Access (E-UTRA), Narrowband Internet of Things (NB-IoT) or New Radio (NR) in a 5G system: the respective signal levels are associated with high quality criteria according to 3GPP standardization and trigger reporting of the respective public land mobile network as a high quality public land mobile network during the cell selection phase.

[0022] Therefore, according to the invention, instead of a value of the extended network selection criterion different from the high quality criterion, it is advantageously possible for the high quality criterion (of a conventionally known value) to simply be applied during the network selection phase. Thus, the actual value of the extended network selection criterion does not have to be stored (e.g. in a subscriber identity module of the user equipment) or transmitted (to the user equipment); it is possible to simply apply the high quality criterion (already known to the user equipment).

[0023] According to the invention, for the public land mobile network, the measured signal quality indicators (during the cell selection phase) that are reported to correspond to suitable radio cells (in the cell selection phase) are either reported to the NAS or are an indication that the considered public land mobile network is a high quality network (i.e. the respective measured signal quality indicators correspond to or exceed the high quality criterion). According to the invention, the value of the extended network selection criterion preferably corresponds to a value that exceeds the respective cell selection criterion applied for the respective considered radio access technology (i.e. in the direction of a better signal quality corresponding to the selection process in the cell selection phase). However, the value of the extended network selection criterion corresponds at most to the high quality criterion.

[0024] According to the invention, advantageously, the user equipment is further capable of having or being associated with a Home Public Land Mobile Network (HPLMN), the extended network selection criteria including or taking into account home operator controlled values ​​that are set or adjustable by the HPLMN or its operator, the extended network selection criteria being particularly restrictive compared to cell selection criteria lacking a home operator controlled component, In particular, the extended network selection criterion is at most as restrictive as the high quality criterion, in particular the network selection and application of the extended network selection criterion is triggered when the corresponding reception conditions measured by the user equipment do not correspond to or exceed the cell selection criterion.

[0025] This advantageously enables the home public land mobile network to be able to influence the behavior of the user equipment even when the user equipment is using a visited mobile communication network. For example, advantageously the values ​​of the extended network selection criteria can be adjusted individually (or per group) by the user equipment in order to manipulate the network selection of the user equipment such that a required or intended communication service can be provided by any (home or visited or further) mobile communication network in a stable and reliable manner.

[0026] According to the invention, advantageously, the home operator controlled values ​​of the extended network selection criteria can furthermore preferably correspond to: An additional offset value to be applied compared to the cell selection criteria Absolute Value

[0027] Thus, the present invention advantageously allows for flexible adjustment and modification of home operator controlled values ​​of the extended network selection criteria. In general, the use of offset values ​​is considered to be preferable to the use of absolute values; however, there are (individual) cases, reception conditions, etc., where the use of absolute values ​​may be preferable.

[0028] According to the invention, it is further advantageously possible to provide an indication of the use of a home operator controlled value of the extended network selection criterion or a high quality criterion as the extended network selection criterion, preferably stored in the user equipment, in particular within or as part of a subscriber identity module, or as another secure element or part of a secure element of the user equipment It is provided or transmitted to the user equipment, in particular by the HPLMN or its operator, in particular by using wireless transmission methods.

[0029] By providing different possibilities and ways of modifying and / or storing and / or transmitting home operator control values ​​of extended network selection criteria, according to the invention it is advantageously possible to flexibly manage several important user equipments, such as Internet of Things devices or machine type communication devices, or even groups of user equipments, for example, used for different specific tasks.

[0030] Furthermore, according to the invention, it is advantageously provided that the determination by the user equipment during or during the second step of the mobile communication network corresponding to a suitable radio cell of the considered radio access technology based on the extended network selection criteria is carried out in accordance with: After turning on the user device, After recovering from the lack of coverage, Upon user-triggered network reselection, or Periodically when the user equipment is in a visited communications network, It is possible and preferable to do so.

[0031] Furthermore, according to the invention, it is advantageously possible and preferred that in a third step, if after the second step there is a lack of mobile communication networks corresponding to suitable radio cells of the considered radio access technology having or corresponding to reception conditions that correspond to or exceed the extended network selection criterion, the network selection is continued based on the cell selection criterion instead of the extended network selection criterion.

[0032] Thereby, advantageously, by applying a conventionally known technique, i.e. by applying a cell selection criterion corresponding to the use or consideration in relation to the network selection, it is possible to determine (after its initial stage as described above) for all suitable radio cells reported to the NAS (i.e. according to the invention, this is first performed in a network selection stage corresponding to the second step according to the method of the invention, and not focusing only on a subset that corresponds to or exceeds the extended network selection criterion).

[0033] Furthermore, the present invention relates to a user equipment for realizing network selection in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of said radio cells being respectively associated with at least one mobile communication network of the plurality of mobile communication networks, the user equipment is configured to measure or detect reception conditions for a plurality of radio cells and subsequently to select and / or register with a mobile communication network from a plurality of mobile communication networks, wherein for cell selection by the user equipment a cell selection criterion is defined, and a radio cell of the considered radio access technology is considered to be a suitable radio cell if the corresponding reception conditions measured by the user equipment correspond to or exceed the cell selection criterion for the considered radio access technology, The at least one predefined extended network selection criterion can be applied for network selection by the user equipment, the user equipment being configured as follows: A suitable radio cell of the considered radio access technology is determined by the user equipment based on a cell selection criterion for the considered radio access technology, When initiating network selection according to the automatic network selection mode, only those mobile communication networks which correspond to suitable radio cells of the considered radio access technology are considered for network selection of the user equipment which have or correspond to reception conditions which correspond to or exceed the extended network selection criteria.

[0034] Furthermore, the present invention relates to a system or a mobile communication network for realizing cell selection by a user equipment in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of said radio cells being associated respectively with at least one of said plurality of mobile communication networks, the user equipment is configured for measuring or detecting reception conditions for a plurality of radio cells and subsequently for selecting and / or registering with a mobile communication network from a plurality of mobile communication networks, wherein for cell selection by the user equipment, cell selection criteria are defined, and a radio cell of the considered radio access technology is considered to be a suitable radio cell if the corresponding reception conditions measured by the user equipment correspond to or exceed the cell selection criterion for the considered radio access technology, With regard to network selection by the user equipment, at least one predefined extended network selection criterion may be applied, the system or mobile communication network being configured as follows: A suitable radio cell of the considered radio access technology is determined by the user equipment based on a cell selection criterion for the considered radio access technology, When initiating network selection according to the automatic network selection mode, only those mobile communication networks which correspond to suitable radio cells of the considered radio access technology are considered for network selection of the user equipment which have or correspond to reception conditions which correspond to or exceed the extended network selection criteria.

[0035] Additionally, the present invention relates to a program comprising computer readable program code which, when executed on a computer and / or on a user equipment and / or on a network node of a mobile communication network, or partly on a user equipment and / or partly on a network node of a mobile communication network, causes a computer and / or a user equipment and / or a network node of a mobile communication network to perform the method of the present invention.

[0036] Furthermore, the present invention relates to a computer readable medium comprising instructions which, when executed on a computer and / or on a user equipment and / or on a network node of a mobile communication network, or partly on a user equipment and / or partly on a network node of a mobile communication network, cause a computer and / or a user equipment and / or a network node of a mobile communication network to perform the method of the present invention.

[0037] These and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. The description is given for the purposes of example only, without limiting the scope of the invention. The reference drawings quoted below refer to the attached drawings. [Brief description of the drawings]

[0038] [Figure 1] FIG. 1 illustrates diagrammatically a user equipment in a radio environment comprising multiple radio cells of multiple mobile communication networks. [Diagram 2] FIG. 2 illustrates diagrammatically a situation in which a user equipment measures different signal strengths of different radio cells. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are purely schematic and non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes.

[0040] Where an indefinite or definite article is used when referring to a singular noun e.g. "a", "an" or "the", this includes a plural of that noun unless something else is specifically stated.

[0041] Moreover, the terms first, second, third, etc. in this specification and claims are used to distinguish between similar elements and not necessarily to describe a sequential or chronological order, and the terms so used are interchangeable under appropriate circumstances, with it being understood that the embodiments of the invention described herein are capable of operating in sequences other than those described or illustrated herein.

[0042] In Fig. 1 a user equipment 20 in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks is illustrated in a schematic manner. In the exemplary representation of Fig. 1 a first radio cell 11 is associated or related to a first mobile communication network 100, a second radio cell 12 is associated or related to a second mobile communication network 200 and a third radio cell 13 is associated or related to a third mobile communication network 300.

[0043] Generally speaking, a base station entity is represented for each of the three radio cells 11, 12, 13 that the user equipment 20 detects or "sees": a first base station entity 111 (typically, but not necessarily, of the first mobile communication network 100) generates or provides radio coverage for the first radio cell 11, a second base station entity 112 (typically, but not necessarily, of the second mobile communication network 200) generates or provides radio coverage for the second radio cell 12, and a third base station entity 113 (typically, but not necessarily, of the third mobile communication network 200) generates or provides radio coverage for the third radio cell 13.

[0044] In Figure 1, a user equipment 20 is shown to be located within the radio coverage areas (indicated by dashed circles) of a first radio cell 11, a second radio cell 12 and a third radio cell 13. After measuring or detecting reception conditions for the multiple radio cells 11, 12, 13, the user equipment 20 selects and / or registers with a mobile communication network from the multiple mobile communication networks 100, 200, 300.

[0045] According to the present invention, a cell selection criterion is defined which the user equipment 20 uses for cell selection. The cell selection criterion is shown diagrammatically in Fig. 2, which represents a situation where the user equipment 20 measures different signal strengths of different radio cells 11, 12, 13. The vertical axis of the illustrated diagram corresponds to the signal strength 500 or an indication thereof (such as a field strength value or a signal quality parameter). According to a conventionally known mechanism in mobile communication networks, the user equipment 20 applies a conventionally defined cell selection criterion 510 in a cell selection phase. According to this (conventionally defined) cell selection criterion 510, both the first radio cell 11 and the third radio cell 13 are considered as suitable radio cells (according to or applying the cell selection criterion 510 in the cell selection phase, corresponding to the first step of the method of the present invention), since both radio cells 11, 13 are shown diagrammatically as having or providing (at the position of the user equipment 20) a signal strength corresponding to or exceeding the cell selection criterion 510. According to the invention, in the network selection phase (at least a first part of which corresponds to the second step of the method of the invention), extended network selection criteria 620 are defined and taken into account when selecting a public land mobile network in (the first or initial part of) the network selection phase. Since the extended network selection criteria 620 are typically more demanding or require an increase in the received signal level or quality (as shown diagrammatically in FIG. 2, by which the extended network selection criteria 620 are represented above the conventionally defined cell selection criteria 510, i.e. the extended network selection criteria 620 are particularly restrictive compared to the conventionally defined cell selection criteria 510), only the third radio cell 13, or rather only its associated public land mobile network 300, is taken into account by the user equipment 20 and due to measurements made by the user equipment 20, should be taken into account in the first part of the network selection phase according to the invention. A further criterion is diagrammatically shown in FIG. 2 corresponding to the high quality criterion 630. As mentioned above, the enhanced network selection criteria 620 (for the respective radio access technology) correspond to signal strengths or signal strength levels between the (conventionally used) cell selection criteria 510 and the high quality criteria 630 .Thus, in the exemplary situation shown in Fig. 2, both the first radio cell 11 and the third radio cell 13 are considered as suitable radio cells in the cell selection phase, and only the third radio cell 13 (or its corresponding public land mobile network 300) is considered (initially) in the network selection phase (as only one of the three represented radio cells has corresponding reception conditions measured by the user equipment 20 that correspond to or exceed the extended network selection criteria 620 for the considered radio access technology). In both Figs. 1 and 2, without distinguishing between different radio access technologies, Only radio cells and mobile communication networks are shown. However, it should be understood that this also applies to different radio access technologies, e.g. the third radio cell 13 may exceed the extended network selection criteria 620 only with respect to one particular radio access technology. However, radio cells of another radio access technology and provided or generated by the third base station entity 113 (not specifically represented in Fig. 1 or Fig. 2) may not exceed the respective extended network selection criteria 620 applied with respect to the other radio access technology, and possibly vice versa for the other radio cells 11, 12.

[0046] According to the invention, in a first step a cell selection (i.e. determination by the user equipment 20 of a suitable radio cell based on the (conventionally defined) cell selection criteria 520 for the considered radio access technology) is made, and in a second step, when initiating a network selection according to an automatic network selection mode, only those mobile communication networks corresponding to suitable radio cells of the considered radio access technology are considered for network selection of the user equipment 20 that have or correspond to reception conditions that correspond to or exceed the extended network selection criteria 620. Thereby, by limiting (at least in an early stage of the network selection phase) the candidate networks or candidate public land mobile networks, a higher signal quality or performance of the user equipment 20 can be achieved (if a suitable higher quality public land mobile network can be found in this early stage of the network selection phase according to the invention).

[0047] In accordance with the present invention, the high quality criterion 630 is preferably used as the extended network selection criterion 620 .

[0048] In addition, it is advantageously possible according to the invention, in particular according to a preferred embodiment where the user equipment 20 has or is associated with a home public land mobile network (HPLMN) and the extended network selection criteria 620 include or take into account home operator control values ​​that can be set or adjusted by the HPLMN or its operator. The home operator can influence the network selection process of the user equipment 20. The extended network selection criteria 620 are in particular more restrictive compared to the cell selection criteria 510, or rather compared to taking into account all reported public land mobile networks that correspond to suitable reported radio cells from the start of the network selection phase. As already mentioned, the extended network selection criteria 620 are in particular as restrictive as the high quality criteria 630.

[0049] According to the invention, it is advantageously possible for the network selection stage to be performed differently from what is known so far, by at least initially considering as target networks only those radio cells or corresponding public land mobile networks according to the extended network selection criteria 620 and above. According to the invention, all user equipments (e.g. of a group of user equipments with Internet of Things capabilities etc.) consider all suitable radio cells for network selection, which do not necessarily have to be applied, by applying (a definition of the network selection criteria based on) the extended network selection criteria 620, i.e. by applying values ​​as network selection criteria different from the conventionally defined cell selection criteria 510 (i.e. cell selection criteria). By defining the extended network selection criteria 620 differently from the conventionally performed network selection process, in particular by the extended network selection criteria 620 including or considering home operator control values ​​that can be set or adjusted by the HPLMN or its operator, it is advantageously possible for the home operator (or the operator of the HPLMN, i.e. the operator to which the user equipment 20 "belongs") to influence the behavior of the user equipment 20, in particular the behavior of a part of the group of user equipments being flexible.In an embodiment, for example, for a specific task, such as providing measurements, if a group of e.g. 1000 user equipments is deployed, and if e.g. 900 of these 1000 user equipments can be used and function without any problems, i.e. using as a network selection criterion, based on implementing the present invention, however, the extended network selection criterion 620 (obtained based on the conventionally defined cell selection criterion 510 instead of using or taking into account all of the reported suitable radio cells) does not need to apply any modifications with respect to these 900 functioning user equipments (in particular, there is no need to artificially apply different network selection values ​​compared to the conventionally defined cell selection criterion 510) since the actual (field strength) values ​​to compare may correspond to the same value (e.g. in dB, i.e. if the extended network selection criterion 620 is defined as including an additional summand compared to the conventionally defined cell selection criterion 510, the additional summand will be zero (e.g. in dB)) despite the (new) definition of the extended network selection criterion 620. However, for the remaining 100 user equipments (which are not necessarily fully functional), the present invention, through the proposed modified definition of the network selection criteria, i.e. the extended network selection criteria 620, provides the possibility for the home public land mobile network to apply more restrictive network selection criteria (based on the conventionally defined cell selection criteria 510 compared to the use or consideration of all reported suitable radio cells), leading to a reduced rate of failures of such user equipments when communicating with the respective mobile communication networks to which they are connected.

[0050] According to the present invention, since only (mobile) networks that pass the (to be applied) network selection criteria are initially considered in the network selection process, there is preferably only a modification for the first part of the network selection process (i.e., corresponding to the second step of the method of the present invention). However, if no public land mobile network is found in this initial part of the network selection process, the second part of the network selection process (i.e., corresponding to the third step according to the method of the present invention) and all subsequent specified procedures for network selection may remain unchanged while achieving the desired behavior.

[0051] Therefore, according to the invention, it is proposed to introduce and apply a new initial stage or part of the network selection process (second step of the inventive method), namely a new radio technology dependent selection level (extended network selection criteria 620, either in the form of absolute values ​​or in the form of offset values ​​per radio access technology), which can be provided by signaling means from the HPLMN or retrieved from a respective field on the SIM maintained by the HPLMN. This selection level or these selection levels are applied to the networks in the PLMN list during the selection process.

[0052] The new selection levels (NSL or enhanced network selection criteria 620) can be stored as absolute numbers or offset values ​​with respect to either the high quality level (high quality criteria 630) or the cell selection criteria (conventionally used cell selection criteria 510). The new selection levels (enhanced network selection criteria 620) should only be applied when they are within the range between the HQ level (high quality criteria 630) and the cell selection criteria (conventionally used cell selection criteria 510). This ensures that no changes are needed on the lower layers (i.e. AS - Access Layer) since the information conventionally reported to the NAS (i.e. signal quality indication based on measurements performed by the user equipment 20) is sufficient.

[0053] A variant is preferred which provides an offset (i.e. an additional value to be added to the definition of the conventionally defined cell selection criterion 510 or subtracted from the definition of the high quality criterion 630) to be applied or used in the new initial stage or part of the network selection process (second step of the inventive method). After the new initial stage or part of the network selection process according to the invention (second step of the inventive method) the network selection procedure may remain unchanged with respect to the conventional process, since in this subsequent network selection process all reported suitable radio cells are taken into account.

[0054] According to the present invention, the network selection phase begins as follows. - when switching on or recovering from a lack of coverage, the last registered PLMN (extended network selection criterion 620) with a field strength higher than the NSL or an EPLMN (equivalent public land mobile network) is selected, either the last registered PLMN (extended network selection criterion 620) with a field strength higher than the NSL or, as an option configured on the SIM, an HPLMN (extended network selection criterion 620) with a field strength higher than the NSL or the highest priority EHPLMN with a field strength higher than the available NSL (extended network selection criterion 620); -If no such network is available or for reselection: - Either an HPLMN with a field strength greater than the NSL (Extended Network Selection Criteria 620) or a highest priority EHPLMN with a field strength greater than the available NSL (Extended Network Selection Criteria 620); - each PLMN / access technology combination (in order of priority) that has a field strength greater than the NSL (Extended Network Selection Criteria 620) in the "User Controlled PLMN Selector with Access Technology" data file in the SIM; - each PLMN / access technology combination having a field strength greater than the NSL (extended network selection criteria 620) in the "operator-controlled PLMN selector with access technology" data file stored in the SIM (in priority order) or in the ME (in priority order); -Combination of other PLMNs / access technologies with "higher quality" signals received in random order. If no network is available that meets the above criteria, a further step of the network selection phase is to apply a procedure known in the art, namely the following procedure: - at switch-on or recovery from lack of coverage, either the HPLMN or the highest priority EHPLMN available is selected from the last registered PLMN or EPLMN to the last registered PLMN, or as an option configured on the SIM; -Then: - Either HPLMN or the highest priority EHPLMN available; -each PLMN / access technology combination (in order of priority) in the "User-controlled PLMN selector with access technology" data file in the SIM; - each PLMN / access technology combination in an "operator controlled PLMN selector with access technologies" data file stored in the SIM (in priority order) or in the ME (in priority order); -Other PLMN / access technology combinations in decreasing order of signal quality.

[0055] As already mentioned, according to an embodiment of the present invention, the high quality criterion is applied as an extended network selection criterion 620 during an initial stage or stages of the network selection process. Thus, no new parameters on the SIM are required, only the network selection process is modified in the same way as above (i.e. the NSL (extended network selection criterion 620) is replaced by the high quality criterion). According to a further variant of this embodiment, a control flag (i.e. an indication carrying essentially one bit of information) is additionally introduced to control whether the network selection process follows or applies the new procedure according to the present invention. The control flag is in particular provided by signaling means from the HPLMN or is taken from the respective electric field on the SIM maintained by the HPLMN.

Claims

1. 1. A method for realizing network selection by a user equipment in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of the radio cells being associated with at least one mobile communication network respectively of the plurality of mobile communication networks, the method comprising: said user equipment measures or detects reception conditions for said plurality of radio cells and subsequently selects and / or registers with a mobile communication network from among said plurality of mobile communication networks, wherein for cell selection by said user equipment a cell selection criterion is defined, and a radio cell of a considered radio access technology is considered to be a suitable radio cell if the corresponding reception conditions measured by said user equipment correspond to or exceed the cell selection criterion for said considered radio access technology, With respect to network selection by the user equipment, predetermined extended network selection criteria are applied, the method comprising: In a first step, a suitable radio cell of the considered radio access technology is determined by the user equipment based on the cell selection criterion for the considered radio access technology, in a second step, when initiating a network selection according to an automatic network selection mode, only those mobile communication networks which correspond to suitable radio cells of said considered radio access technology are considered for network selection of said user equipment which have or correspond to reception conditions which correspond to or exceed said extended network selection criterion, 11. The method of claim 10, wherein the user equipment has or is associated with a Home Public Land Mobile Network (HPLMN), and the extended network selection criteria include or take into account home operator controlled values ​​that are set or adjustable by the HPLMN or its operator, and the extended network selection criteria are particularly restrictive compared to the cell selection criteria lacking a home operator controlled component.

2. The extended network selection criterion corresponds to a high quality criterion, the high quality criterion being: As a radio access technology, Global System for Mobile communications (GSM) corresponds to the signal levels associated with high quality reception in public land mobile networks according to 3GPP standardization, 2. The method of claim 1, wherein for a UMTS Terrestrial Radio Access Network (UTRAN), an Evolved UMTS Terrestrial Radio Access (E-UTRA), a Narrow-Band Internet-of-Things (NB-IoT) or a New Radio (NR) in a 5G system, the respective signal levels are associated with the high quality criteria according to the 3GPP standardization, triggering reporting of the respective public land mobile network as a high quality public land mobile network in a cell selection phase.

3. The method of claim 2, characterized in that the extended network selection criteria are at most as restrictive as the high quality criteria.

4. The home operator controlled values ​​of the extended network selection criteria are: an offset value that is additionally retained compared to the cell selection criterion; or 4. The method according to claim 1, wherein the absolute value corresponds to the absolute value.

5. The instruction to use the home operator controlled value of the extended network selection criteria or the high quality criterion as the extended network selection criterion may further comprise: In particular, stored in or as part of a subscriber identity module or as part of another secure element or elements of the user equipment; and / or 5. The method according to any one of claims 1 to 4, characterized in that it is provided or transmitted to the user equipment by the HPLMN or its operator, in particular by using wireless transmission methods.

6. determining by the user equipment during or within the second step a mobile communication network corresponding to a suitable radio cell of the considered radio access technology based on the extended network selection criteria, After turning on the user equipment, After recovering from the lack of coverage, Upon a network reselection triggered by the user, or 6. The method according to any one of claims 1 to 5, characterized in that it is performed periodically when the user equipment is in a visited communications network.

7. 7. The method according to claim 1, characterized in that in a third step after the second step, if there is a shortage of mobile communication networks corresponding to suitable radio cells of the considered radio access technology having or corresponding to reception conditions that correspond to or exceed the extended network selection criterion, then the network selection continues based on the cell selection criterion instead of the extended network selection criterion.

8. A user equipment for realizing network selection in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of the radio cells being associated with at least one mobile communication network of the plurality of mobile communication networks, said user equipment measures or detects reception conditions for said plurality of radio cells and subsequently selects and / or registers with a mobile communication network from said plurality of mobile communication networks, wherein for cell selection by said user equipment a cell selection criterion is defined, and a radio cell of a considered radio access technology is considered to be a suitable radio cell if the corresponding reception conditions measured by said user equipment correspond to or exceed the cell selection criterion for said considered radio access technology, applying at least one predefined extended network selection criterion for network selection by the user equipment; The user equipment, a suitable radio cell for a considered radio access technology is determined by the user equipment based on the cell selection criterion for the considered radio access technology; when initiating a network selection according to an automatic network selection mode, only those mobile communication networks which correspond to suitable radio cells of said considered radio access technology are considered for network selection of the user equipment which have or correspond to reception conditions which correspond to or exceed said extended network selection criterion, The user equipment has or is associated with a Home Public Land Mobile Network (HPLMN), and the extended network selection criteria include or take into account home operator controlled values ​​that are set or adjustable by the HPLMN or its operator, and the extended network selection criteria are particularly restrictive compared to the cell selection criteria lacking a home operator controlled component.

9. A system or a mobile communication network for realizing cell selection by a user equipment in a radio environment comprising a plurality of radio cells of a plurality of mobile communication networks, each of the radio cells being associated with at least one of the plurality of mobile communication networks, said user equipment measures or detects reception conditions for said plurality of radio cells and subsequently selects and / or registers with a mobile communication network from said plurality of mobile communication networks, wherein for cell selection by said user equipment a cell selection criterion is defined, and a radio cell of a considered radio access technology is considered to be a suitable radio cell if corresponding reception conditions measured by said user equipment correspond to or exceed said cell selection criterion for said considered radio access technology, At least one predefined extended network selection criterion is applied for network selection by the user equipment, and the system or the mobile communication network further comprises: a suitable radio cell for a considered radio access technology is determined by the user equipment based on the cell selection criterion for the considered radio access technology; 13. A system or mobile communication network comprising: a mobile communication network including a home operator controlled component, the mobile communication network including a home operator controlled component, the user equipment having or associated with a home public land mobile network (HPLMN); a mobile communication network including a home operator controlled component, the mobile communication network including a home operator controlled component, the user equipment having or associated with a home public land mobile network (HPLMN); a mobile communication network including a home operator controlled component, the mobile communication network including a home operator controlled component, the user equipment having or associated with a home public land mobile network (HPLMN);

10. 8. A program comprising computer readable program code, which when executed on a computer and / or on a user equipment and / or on a network node of a mobile communication network, or partially executed in a user equipment and / or a network node of a mobile communication network, causes said computer and / or said user equipment and / or said network node of the mobile communication network to perform a method according to any one of claims 1 to 7.

11. A computer readable medium comprising instructions which, when executed on a computer and / or on a user equipment and / or on a network node of a mobile communication network, or when executed partially on a part of a user equipment and / or on a network node of a mobile communication network, cause the computer and / or the user equipment and / or the network node of the mobile communication network to carry out a method according to any one of claims 1 to 7.

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