Core network node, radio network node, and methods

Abstract

A method (200) performed by a core network node for handling a Radio Access Technology, RAT, handover of a User Equipment, UE, in a wireless communications network (100) The core network node obtains (201) a first indication indicative of a first Tracking Area, TA (151), where the UE is located. The core network node obtains (202) a second indication indicative of an absence and / or presence of one or more RATs, for the first TA. Based on the first and second indication, the core network node transmits (203) to a first radio network node arranged in the first TA, an instruction to restrict handling of inter RAT handover of the UE in the first TA based on the absence and / or presence of the one or more RATs for the first TA.

Description

[0001] CORE NETWORK NODE, RADIO NETWORK NODE, AND METHODS

[0002] TECHNICAL FIELD

[0003] Disclosed herein is a core network node, a radio network node, and methods performed by the core network node and the radio network node, respectively. Computer programs and carriers are also disclosed. In some aspects, they relate to handling of a Radio Access Technology (RAT) handover of a User Equipment (UE) in a wireless communications network.

[0004] BACKGROUND

[0005] In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and / or UEs, communicate via a Local Area Network such as a Wi-Fi network or a Radio Access Network (RAN) to one or more core networks (CN). The RAN covers a geographical area which is divided into service areas or cell areas, which may also be referred to as a beam or a beam group, with each service area or cell area being served by a radio network node such as a radio access node e.g., a Wi-Fi access point or a radio base station (RBS), which in some networks may also be denoted, for example, a NodeB, eNodeB (eNB), or gNB as denoted in Fifth Generation (5G) telecommunications. A service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node communicates over an air interface operating on radio frequencies with the wireless device within range of the radio network node.

[0006] Specifications for the Evolved Packet System (EPS), also called a Fourth Generation (4G) network, have been completed within the 3rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases, for example to specify a 5G network also referred to as 5G New Radio (NR). Procedures for a 5G System (5GS) is disclosed in 3GPP TS 23.502 V18.5.0. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E-UTRAN / LTE is a variant of a 3GPP radio access network wherein the radio network nodes are directly connected to the EPC core network rather than to Radio Network Controllers (RNCs) used in 3G networks. In general, in E-UTRAN / LTE the functions of a 3G RNC are distributed between the radio network nodes, e.g. eNodeBs in LTE, and the core network. As such, the RAN of an EPS has an essentially “flat” architecture comprising radio network nodes connected directly to one or more core networks, i.e. they are not connected to RNCs. To compensate for that, the E-UTRAN specification defines a direct interface between the radio network nodes, this interface being denoted the X2 interface.

[0007] Multi-antenna techniques may significantly increase the data rates and reliability of a wireless communication system. The performance is in particular improved if both the transmitter and the receiver are equipped with multiple antennas, which results in a Multiple-Input Multiple-Output (MIMO) communication channel. Such systems and / or related techniques are commonly referred to as MIMO.

[0008] As mobile networks evolved to the 5th Generation (5G), security and privacy protections are increasingly improved in 3GPP specified radio access technologies and core network. Lessons learnt from the global deployments, widespread adoption, diverse use cases, and academic research helped identify security vulnerabilities in legacy generations of cellular technologies. It is a natural desire and regulatory requirements that drive the necessity to improve security posture that offer higher levels of trust, assurance, reliability, and robustness to reduce security risks for emerging use cases of mobile networks deployed for public and private sectors. Therefore, each generation of mobile network is developed with an aim to offer better security and privacy for the users.

[0009] SUMMARY

[0010] Problems as identified as part of developing embodiments herein will first be discussed.

[0011] The lifecycle of a deployed operational network eventually comes to a decommissioning phase when public land mobile networks (PLMNs) gradually phase out legacy technologies in favor of a latest, feature rich, secure, resilient, and better performing generation of technologies. Until legacy infrastructure is completely removed, the coexistence of modern and legacy technologies presents exploit opportunities to a determined, resourceful, motivated adversary to lure subscribers to access legacy technologies with inherent security and privacy vulnerabilities. Such attacks are referred to as 'bidding-down' attacks. Several procedural and protocol signaling improvements already have been specified in 3GPP specifications to mitigate bidding-down attacks.

[0012] Since operators globally are rolling out 5G Stand-Alone, e.g., 5G NR with 5G Core (5GC), in parallel, the legacy radio access technologies (RAT), such as, General packet radio service(GPRS) I GSM (Global System for Mobile communications) EDGE (Enhanced Data rates for Global Evolution) Radio Access Network (GERAN) and Universal Mobile Telecommunications Service Terrestrial RAN (UTRAN), are gradually being removed. The decommissioning phase is a long-lasting event due to costs, resources, and competing priorities. Often, the change introduces security risks and presents an exploit opportunity that an adversary exploits much later even after the change event is over.

[0013] During the phase of GERAN / UTRAN decommissioning, a PLMN removes its GERAN / UTRAN infrastructure gradually from one area to the next for a nationwide removal lasting for a while. PLMN's subscribers require inter-RAT mobility from NG RAN / LTE to GERAN / UTRAN till PLMN's NG RAN / LTE and GERAN / UTRAN coexist, but at the same time be protected from adversary's GERAN / UTRAN false base station. Removal of GERAN / UTRAN by a PLMN, presents an exploit opportunity for an attacker to position its GERAN / UTRAN False Base Stations (FBS) as a Man-in-the-Middle (MitM) tool to eavesdrop exchange between the UE and the network for further building an attack by using knowledge of compromised UE's identity, location, and its communication. Multi- RAT UEs can be tricked into accessing a legacy, less secure RAT provided by the adversary, especially when the PLMN has removed the GERAN / UTRAN RAN nodes.

[0014] Furthermore, the problem may extend to any system where there is a RAT is not configured to the area but is being advertised to a UE, by an attacker or FBS.

[0015] Therefore, an effective and fit-for-purpose risk mitigation measure to mitigate security risks is required that is effective.

[0016] An object of embodiments herein is to provide efficient and secure RAT handover in wireless communications networks.

[0017] According to a first aspect, a method performed by a core network node for handling a RAT handover of a UE in a wireless communications network. The core network node obtains a first indication indicative of a first Tracking Area (TA) where the UE is located. The core network node obtains a second indication indicative of an absence and / or presence of one or more RATs, for the first TA. The core network node, based on the first and second indication, transmits to a first radio network node arranged in the first TA , an instruction to restrict handling of inter RAT handover of the UE in the first TA based on the absence and / or presence of the one or more RATs for the first TA .

[0018] According to a second aspect, a method performed by a first radio network node for handling a RAT handover of a UE in a wireless communications network. The first radio network node being arranged in a first TA. The first radio network node receives from a core network node, an instruction to restrict handling of inter RAT handover of the UE in the first TA based on an absence and / or presence of one or more RATs for the first TA. In response to detecting a need for performing a handover of the UE to a second radio network node, the first radio network node handles the handover as restricted according to the received instruction.

[0019] According to a third aspect, a core network node configured to handle a Radio Access Technology, RAT, handover of a User Equipment, UE, in a wireless communications network is provided. The core network node being configured to: obtain a first indication indicative of a first Tracking Area, TA, where the UE is located, obtain a second indication indicative of an absence and / or presence of one or more RATs, for the first TA , based on the first and second indication, transmit to a first radio network node arranged in the first TA , an instruction to restrict handling of inter RAT handover of the UE in the first TA based on the absence and / or presence of the one or more RATs for the first TA .

[0020] According to a fourth aspect, a first radio network node configured to handle a Radio Access Technology, RAT, handover of a User Equipment, UE, in a wireless communications network is provided. The radio network node being arranged in a first Tracking Area, TA, wherein the first radio network node is configured to: receive from a core network node , an instruction to restrict handling of inter RAT handover of the UE in the first TA based on an absence and / or presence of one or more RATs for the first TA , in response to detecting a need for performing a handover of the UE to a second radio network node , handle the handover as restricted according to the received instruction.

[0021] A fifth aspect relates to a computer program which comprises instructions, which when executed by a processor, causes the processor to perform a method according to the first aspect.

[0022] A sixth aspect relates to a computer program which comprises instructions, which when executed by a processor, causes the processor to perform a method according to the second aspect.

[0023] A seventh aspect relates to a carrier which comprises a computer program for performing the method according to the first aspect, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

[0024] An eighth aspect relates to a carrier which comprises a computer program for performing the method according to the second aspect, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

[0025] Since the instruction is sent to the first radio network node, inter RAT handover to RATs that are absent from the first TA can be avoided, which thereby avoids that the UE is moved to a false RAT, keeping the UE safe, in an efficient manner.

[0026] In an embodiment of the first to fourth aspects, the instruction indicates to the first radio network node to refrain from handling the inter RAT handover when the RAT handover is to a RAT indicated by the instruction to be absent in the first TA.

[0027] In an embodiment of the first to fourth aspects, the instruction indicates that the first radio network node (110) shall only handle RAT handover when the RAT handover is to a RAT indicated by the instruction to be present in the first TA.

[0028] In an embodiment of the method according to the first aspect, the second indication only indicates the one or more RATs present for the first TA.

[0029] In an embodiment of the third to fourth aspects, the one or more RATs is GSM EDGE Radio Access Network, and / or Universal Mobile Telecommunications Service Terrestrial Radio Access Network.

[0030] BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Examples of embodiments herein are described in more detail with reference to attached drawings in which:

[0032] Fig. 1 is a schematic block diagram illustrating example embodiments of a wireless communications network,

[0033] Fig. 2 is a flowchart depicting example embodiments of a method,

[0034] Fig. 3 is a flowchart depicting example embodiments of a method,

[0035] Fig. 4 is schematic block diagram illustrating example embodiments,

[0036] Fig. 5 is a flowchart depicting a combined flow chart and sequence diagram illustrating an example scenario with example embodiments of a network node, Fig. 6 is a schematic block diagram illustrating example embodiments of a core network node,

[0037] Fig. 7 is a schematic block diagram illustrating example embodiments of a radio network node,

[0038] Fig. 8 shows an example of a communication system in accordance with some embodiments,

[0039] Fig. 9 shows a UE in accordance with some embodiments,

[0040] Fig. 10 shows a network node in accordance with some embodiments,

[0041] Fig. 11 is a block diagram of a host,

[0042] Fig. 12 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized, and Fig. 13 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments.

[0043] DETAILED DESCRIPTION

[0044] Embodiments herein may relate to prevent UE camping on GERAN / UTRAN types of RATs in specified TAs if the GERAN / UTRAN is removed in the specified TA of a PLMN. Therefore, if the UE is reporting presence of GERAN / UTRAN RAT with better strength and quality of the signal, there is a likelihood that false base station GERAN / UTRAN is operating in UE's location and should not be handed over to. While GERAN / UTRAN is the biggest concern, the embodiments herein further relates to any suitable RAT in a corresponding manner.

[0045] Embodiments herein may relate to when a UE is in Registration Management (RM) REGISTERED state for both the Connection Management (CM) CONNECTED and CM- IDLE states. A registration area update procedure by the UE may inform the network of UE's current location TA. The inter-RAT mobility restriction may then be enforced in the network, and not provided to the UE. Embodiments herein may instead rely on a network enforced inter-RAT mobility restriction from NG RAN / LTE to GERAN / UTRAN for the UE in a specified tracking area TA depending on a local policy set in a core network node, e.g., an AMF / MME. The local policy may consider a removal of a legitimate GERAN / UTRAN in the TA. The local policy maintained by the AMF / MME may ensure a mapping of TA and a 3rd Generation Partnership Project (3GPP) GERAN / UTRAN presence / absence indicator. Based on this awareness, the core network node may pass an instruction from AMF / MME to NG RAN / LTE that prevents a source radio network node not to initiate inter-RAT handover of a UE from NG RAN / LTE to GERAN / UTRAN in the specified TA of UE's current location in a PLMN.

[0046] Advantages of embodiments may be summarized as follows: a subscriber action and awareness that a PLMN has removed GERAN / UTRAN and / or other RAT are not required by embodiments herein, thereby improving efficiency.

[0047] Independence of UE capabilities may be achieved since a core network node may define a policy, i.e., absence and / or presence of RATs in a TA, and a radio network node may be configured to enforce said policy,

[0048] Improved security since information may only be conveyed after a Security Mode Command (SMC) over non-access stratum (NAS) and access stratum (AS). Network enforced inter-RAT mobility restriction for UEs in RRC CONNECTED. In embodiments herein, there may be no need to enforce the restriction on the UE, as it will be enforced on the radio network node side. .

[0049] Fig. 1 is a schematic overview depicting a wireless communications network 100 wherein embodiments herein may be implemented. The wireless communications network 100 comprises one or more RANs and one or more CNs. The wireless communications network 100 may use 5G NR, but may further use a number of other different RAT technologies, such as, Wi-Fi, LTE, LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications / enhanced Data rate for GSM Evolution (GSM / EDGE), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations.

[0050] Radio network nodes such as a first radio network node 110 and optionally a second radio network node 112, operate in the wireless communications network 100. The first radio network node 110 and / or the second radio network node 112 may respectively provide a number of cells referred, and may use these cells for communicating with any one or more suitable UEs operating in these cells. The first radio network node 110 and / or the second radio network node 112 may respectively be a transmission and reception point e.g. a radio access network node such as a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNodeB, eNode B), an NR Node B (gNB), a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a transmission arrangement of a radio base station, a stand-alone access point, a Wireless Local Area Network (WLAN) access point, an Access Point Station (AP STA), an access controller, a UE acting as an access point or a peer in a Device to Device (D2D) communication, or any other network unit capable of communicating with a UE within any cell served by the first radio network node 110 and / or the second radio network node 112, e.g. depending on the radio access technology and terminology used.

[0051] UEs may operate in the wireless communications network 100 such as the UE 120. UEs as used herein may respectively provide radio coverage by means of a number of antenna beams, also referred to as beams herein. UEs as used herein may respectively e.g. be an NR device, a mobile station, a wireless terminal, an NB-loT device, an eMTC device, an NR RedCap device, a CAT-M device, a Wi-Fi device, an LTE device and a non-access point (non-AP) STA, a STA, that communicates via a base station such as e.g. the network node 110, one or more Access Networks (AN), e.g. RAN, to one or more core networks (CN). It should be understood by the skilled in the art that the UE relates to a non-limiting term which means any UE, terminal, wireless communication terminal, user equipment, (D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station communicating within a cell.

[0052] Core network nodes such as the core network node 130 may operate in the wireless communications network 100. The core network node 130, may be or comprise an Access & Mobility Management Function (AMF) and / or a Mobility Management Entity (MME).

[0053] In the wireless communications network 100, one or more Tracking Areas (TAs) may be present such as a first TA 151, a second TA 152, and / or a third TA 153. The different TAs may be associated with different RATs being present or absent therein. TAs, e.g., the first TA 151 , as used herein may comprise a single cell or multiple cells.

[0054] Methods herein may be performed by the core network node 130 and / or the first radio network node 110. As an alternative, a Distributed Node (DN) and functionality, e.g. comprised in a cloud 140 as shown in Fig. 1 , may be used for performing or partly performing the methods and embodiments herein.

[0055] Embodiments herein may relate to a presence / absence indicator based local policy maintained by the core network node 130 per TA. The presence / absence indicator may typically be for 5G or LTE and / or GERAN / UTRAN but may also apply to any other RAT(s). Embodiments herein may be used to enforce inter-RAT mobility restriction in the UE's 120 location identified by the first TA 151. The inter-RAT mobility restriction of some embodiments herein may prevent the UE 120 to be handed over from NG RAN / LTE to GERAN / UTRAN in the first TA 151 where GERAN / UTRAN is removed by the PLMN. Such mobility restriction may mitigate risk of false base stations operating in GERAN / UTRAN in the UE's 120 current location from where the UE 120 is performing a registration procedure. As used herein, the registration procedure could be the initial registration, periodic registration update and mobility registration update. The registration procedure may make the core network node 130 and / or the first radio network node 110 aware of the UE's 120 TA, e.g., the first TA 151 , based current location of the UE 120, that then may be used to identify whether PLMN's GERAN / UTRAN, or any other one or more RATs is operational or removed.

[0056] Embodiments herein address at least some above-mentioned problems. Below follows a number of embodiment which may be performed in any suitable combination.

[0057] Fig. 2 illustrates a flow chart of a method 200 performed by the core network node 130 for handling a RAT handover of the UE 120 in the wireless communications network 100.

[0058] The method comprises the following actions in any suitable order. Boxes in Fig. 2 illustrated by dashed borders may be considered optional actions.

[0059] Action 201

[0060] The core network node 130 obtains a first indication indicative of the first TA 151 where the UE 120 is located. The first indication may be obtained by registration of the first UE 120 with the core network node 130. Any other suitable method of obtaining the first indication of the first TA 151 may apply to embodiments herein.

[0061] Action 202

[0062] The core network node 130 obtains a second indication indicative of an absence and / or presence of one or more RATs, for the first TA 151 . The second indication may be obtained from a stored list or policy of which RATs are absent and / or present for the first TA 151 . The RATs may typically be any one or more 3GPP RAT, in particular absence of UTRAN or GERAN, or presence of other RATs, however, the one or more RATs may comprise any one or more out of: GERAN, UTRAN, 5G, LTE, 6G, Bluetooth, WiMAX, Non-3GPP trusted, Non-3GPP untrusted, IEEE802.11a / ab / g / n (Wi-Fi), CDMA, WCDMA, CDMA-2000.

[0063] In some embodiments, the second indication only indicates the one or more RATs present for the first TA 151 , i.e., the usable RATs may be indicated for one or more cells in the first TA 151 , and it can then be deduced that all other RATs shall not be used in the first TA 151. In some embodiments, the second indication may be represented by a Table 1 as below in Table 1 , wherein there is a GERAN / UTRAN indicator per Location, where the location is identified in CN by TAI, and the same location is identified in RAN by NR Cell Global Identifier (NCGI) and / or an Evolved Cell Global Identifier (ECGI). The location may be identified in CN, e.g., by the core network node 130, by a Tracking Area Identity (TAI) defined by a Tracking Area Code (TAC), Mobile Network Code, and a Mobile Country Code (MCC), as used by the CN, or where the location is represented by MNC, MCC, a Cell ID, and a base station ID, i.e. , NCGI and / or ECGI as used by RAN, e.g., the first radio network node 110. The TAI is a globally unique identifier, as well as the ECGI or NCGI. A location is identified in CN by TAI, and same location is identified in RAN by NCGI / ECGI.

[0064] Table 1 GERAN / UTRAN indicator per TA

[0065] While the Table 1 indicates presence or absence of GERAN and / or LITRAN per location, any one or more other RAT may also be used in the same corresponding manner.

[0066] In some embodiments, the second indication indicates that GERAN and / or LITRAN is absent in the first TA 151.

[0067] In some embodiments, the second indication indicates that 5G NR and / or LTE is present in the first TA 151.

[0068] Action 203

[0069] The core network node 130, based on the first and second indication, transmits to the first radio network node 110 arranged in the first TA 151 , an instruction to restrict handling of inter RAT handover of the UE in the first TA 151 based on the absence and / or presence of the one or more RATs for the first TA 151 .

[0070] In some embodiments, the instruction indicates to the first radio network node 110 to refrain from handling the inter RAT handover when the RAT handover is to a RAT indicated by the instruction to be absent in the first TA 151. Indicated to be absent may be explicitly indicated or indicated by not explicitly being indicated to be present.

[0071] In some embodiments, the instruction indicates that the first radio network node 110 shall only handle inter RAT handover when the inter RAT handover only is to a RAT indicated by the instruction to be present in the first TA 151 . This allows for efficient restriction of RATs by only having to supply RATs which shall be usable, and by default, all other may not be used.

[0072] In some embodiments, the instruction indicates that GERAN and / or LITRAN is restricted in the first TA 151 and / or that only 5G NR and / or LTE is usable for inter RAT handover.

[0073] In some embodiments herein, for practical implementation, interoperability standardization may be needed such that the instruction may be used between the core network node 130 and the first radio network node 110, when they belong to different operators. The instruction may be transmitted over S1AP and / or NGAP protocols.

[0074] Fig. 3 illustrates a flow chart of a method 300 performed by the first radio network node 110 for handling a RAT handover of the UE 120 in the wireless communications network 100. The radio network node 110 is arranged in the first TA 151. The method comprises the following actions in any suitable order. Boxes in Fig. 3 illustrated by dashed borders may be considered optional actions. Features described with respect to actions 201-203 may apply to below actions 301-303 in a corresponding manner and vice versa.

[0075] Action 301

[0076] The first radio network node 110 receives from the core network node 130, an instruction to restrict handling of inter RAT handover of the UE in the first TA 151 based on an absence and / or presence of one or more RATs for the first TA 151 , e.g., as a result of actions 201-203.

[0077] In some embodiments, the instruction indicates to the first radio network node 110 to refrain from handing the inter RAT handover when the inter RAT handover is to a RAT indicated by the instruction to be absent in the first TA 151.

[0078] In some embodiments, the instruction indicates that the first radio network node 110 that shall only handle RAT handover when the RAT handover is to a RAT indicated by the instruction to be present in the first TA 151 . In this way, the instruction may be efficiently communicated only what is allowed to use, and it can be assumed that all other RATs are non-secure and may be part of an attack or malicious activity. In some embodiments, the instruction indicates that GERAN and / or LITRAN is restricted in the first TA 151 and / or that only 5G NR and / or LTE is usable for inter RAT handover.

[0079] Action 302

[0080] The first radio network node 110 detects a need for performing a handover of the UE 120 to the second radio network node 112. The detection may comprise receiving one or more measurement reports from the UE 120, e.g., indicating that other cells or base stations would provide better signal quality.

[0081] Action 303

[0082] The first radio network node 110 in response to detecting the need for performing a handover of the UE to a second radio network node 112, handling the handover as restricted according to the received instruction.

[0083] For example, if it can be determined based on the received instruction that a RAT shall be restricted to use as it should not be present in the first TA 151 , then the first radio network node 110 will not initiate a handover of the first UE 120.

[0084] Fig. 4. Illustrates example scenarios of embodiments herein. In a first scenario a TA-3 of Fig. 4 may exemplify the first TA 151 of embodiments herein. As depicted in the Fig. 4, a PLMN has removed GERAN / UTRAN as RAT from TA-3, while these RATs may still be operating in TA-1 and TA-2. The UE 120 may perform a registration procedure for initial registration, periodic registration, or mobility update registration, e.g., as part of action 201 , and if the UE 120 happens to be in TA-3, then embodiments herein may comprise a policy logic screening as part of the core network node 130, where TA level information of the UE 120 is triggered by detecting that the UE 120 is now in TA-3, e.g., as part of action 201 , where the PLMN has removed GERAN / UTRAN. Subsequently, the core network node 130 may instruct the RAN nodes in TA-3, i.e., the first radio network node 110 and optionally any other radio network node in the first TA 151, to prohibit the mobility of the UE 120 by restricting inter-RAT handover from NG RAN / LTE to GERAN / UTRAN. Thus, the UE 120 is prevented from camping on a GERAN / UTRAN base station, e.g., the second radio network node 112; as if such is present to the UE 120, in TA-3, it is potentially an adversarial false base station.

[0085] In another example scenario the first TA 151 may represent the TA-1 or the TA2, such as when the UE 120 performs a registration procedure from its presence in TA-1 or TA-2, the core network node 130 may determine that PLMN's GERAN / UTRAN is operational so it may in these example scenarios allow inter-RAT mobility to handover the UE 120 from NG RAN / LTE to GERAN / UTRAN.

[0086] Fig. 5. Illustrates an example scenario of embodiments herein. The policy-based location aware GERAN / UTRAN mobility restriction solution sequence flow of events is captured in Fig. 5:

[0087] The core network node 130 may obtain and / or maintain 501 an indication of the absence and / or presence of RATs in a number of different TAs as part of a policy, e.g., as part of action 201.

[0088] The UE 120 may perform a registration procedure 502, 503 with the first radio network node 110 and with the core network node 130, e.g., as part of action 201.

[0089] When the UE 120 is registered with the core network node 130, the core network node 120 may, based on the registration, and as part of action 201, determine 504 the location of the UE 120, i.e., the first TA 151, and determine if a RAT, e.g., UTRAN / GERAN, is / has been removed from the first TA 151 , e.g., as part of action 202, and if so, the core network node 130 may instruct 505 the first radio network node 110 to restrict the usage of UTRAN / GERAN if they have been removed from the first TA 151 , or restrict usage of any other RAT if not detected to be part of the first TA 151 , e.g., as part of action 203 or 301.

[0090] Further, the UE 120 may establish 506 measurement reports indicating to the first radio network node 110 to perform a handover to the second radio network node 112, e.g., as in action 302. When the handover is restricted due to the instruction from the core network node 130, i.e., since there should be no GERAN / UTRAN presence in the first TA 151 but it is still provided by the second radio network node 112, then the first radio network node 110 will refrain 507 from performing a handover to the second radio network node 112 as it may be an attacker or other malicious entity, e.g., as part of action 303.

[0091] To perform the method actions above, the core network node 130 may comprise an arrangement depicted in Fig. 6.

[0092] The core network node 130 may comprise an input and output interface 600 configured to communicate with any suitable entity described herein. The input and output interface 600 may comprise a wireless receiver not shown, and a wireless transmitter not shown.

[0093] The core network node 130 may be configured to perform the actions above. The core network node 130 is configured to handle RAT handover of the UE 120 in the wireless communications network 100. The core network node 130 is configured to: obtain a first indication indicative of the first TA 151 , where the UE 120 is located, obtain a second indication indicative of an absence and / or presence of one or more RATs, for the first TA 151, based on the first and second indication, transmit to a first radio network node 110 arranged in the first TA 151, an instruction to restrict handling of inter RAT handover of the UE 120 in the first TA 151 based on the absence and / or presence of the one or more RATs for the first TA 151.

[0094] In some embodiments, the instruction indicates to the first radio network node 110 to refrain from handling the inter RAT handover when the RAT handover is to a RAT indicated by the instruction to be absent in the first TA 151.

[0095] In some embodiments, the instruction indicates that the first radio network node 110 shall only handle inter RAT handover when the inter RAT handover only is to a RAT indicated by the instruction to be present in the first TA 151.

[0096] In some embodiments, the second indication only indicates the one or more RATs present for the first TA 151.

[0097] The embodiments herein may be implemented through a processor or one or more processors, such as at least one processor 640 of a processing circuitry in the core network node 130 depicted in Fig. 6, together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the core network node 130. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the core network node 130.

[0098] The core network node 130 may further comprise respective a memory 650 comprising one or more memory units. The memory comprises instructions executable by the processor in the core network node 130. The memory is arranged to be used to store instructions, data, configurations, and applications to perform the methods herein when being executed in the core network node 130. In some embodiments, a computer program 660 comprises instructions, which when executed by the at least one processor, cause the at least one processor of the core network node 130 to perform the actions above.

[0099] In some embodiments, a respective carrier 670 comprises the respective computer program, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

[0100] The core network node 130 may further be configured to perform any one or more out of actions the above-mentioned actions in any suitable order, e.g., by used of the at least one processor 640 and / or by use of a control unit, and / or by use of any other suitable means.

[0101] Those skilled in the art will also appreciate that the functional modules in the core network node 130, described below may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g. stored in the core network node 130, that when executed by the respective one or more processors such as the at least one processor described above cause the respective at least one processor to perform actions according to any of the actions above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a system-on-a-chip (SoC).

[0102] To perform the method actions above, the first radio network node 110 may comprise an arrangement depicted in Fig. 7.

[0103] The first radio network node 110 may comprise an input and output interface 700 configured to communicate with any suitable entity described herein. The input and output interface 700 may comprise a wireless receiver not shown, and a wireless transmitter not shown.

[0104] The first radio network node 110 may be configured to perform the actions above.

[0105] The first radio network node 110 is configured to handle a RAT handover of the UE 120 in the wireless communications network 100.

[0106] The first radio network node 110 is arranged in the first TA 151 , wherein the first radio network node 110 is configured to: receive from the core network node 130, an instruction to restrict handling of inter RAT handover of the UE 120 in the first TA 151 based on an absence and / or presence of one or more RATs for the first TA 151 , in response to detecting a need for performing a handover of the UE 120 to the second radio network node 112, handle the handover as restricted according to the received instruction.

[0107] In some embodiments, the instruction indicates to the first radio network node 110 to refrain from handing the inter RAT handover when the inter RAT handover is to a RAT indicated by the instruction to be absent in the first TA 151.

[0108] In some embodiments, the instruction indicates that the first radio network node 110 that shall only handle RAT handover when the RAT handover is to a RAT indicated by the instruction to be present in the first TA 151.

[0109] The embodiments herein may be implemented through a processor or one or more processors, such as at least one processor 740 of a processing circuitry in the first radio network node 110 depicted in Fig. 7, together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the first radio network node 110. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the first radio network node 110.

[0110] The first radio network node 110 may further comprise respective a memory 750 comprising one or more memory units. The memory comprises instructions executable by the processor in the first radio network node 110. The memory is arranged to be used to store instructions, data, configurations, and applications to perform the methods herein when being executed in the first radio network node 110.

[0111] In some embodiments, a computer program 760 comprises instructions, which when executed by the at least one processor, cause the at least one processor of the first radio network node 110 to perform the actions above.

[0112] In some embodiments, a respective carrier 770 comprises the respective computer program, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium. The first radio network node 110 may further be configured to perform any one or more out of actions the above-mentioned actions in any suitable order, e.g., by used of the at least one processor 740 and / or by use of a control unit, and / or by use of any other suitable means.

[0113] Those skilled in the art will also appreciate that the functional modules in the first radio network node 110, described below may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g. stored in the first radio network node 110, that when executed by the respective one or more processors such as the at least one processor described above cause the respective at least one processor to perform actions according to any of the actions above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a system-on-a-chip (SoC).

[0114] ADDITIONAL EXPLANATION

[0115] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0116] Fig. 8 shows an example of a communication system 800 in accordance with some embodiments.

[0117] In the example, the communication system 800, e.g., the wireless communications network 100, includes a telecommunication network 802 that includes an access network 804, such as a radio access network, RAN, and a core network 806, which includes one or more core network nodes 808, e.g., the core network node 130. The access network 804 includes one or more access network nodes, such as the first radio network node 110 and may be referred to as network nodes 810, or any other similar 3GPP access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 802 includes one or more Open-RAN ORAN network nodes. An ORAN network node is a node in the telecommunication network 802 that supports an ORAN specification e.g., a specification published by the O-RAN Alliance, or any similar organization and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 802, including one or more network nodes 810 and / or core network nodes 808.

[0118] Examples of an ORAN network node include an open radio unit 0-Rll, an open distributed unit 0-Dll, an open central unit O-CU, including an O-CU control plane O-CU- CP or an O-CU user plane O-CU-UP, a RAN intelligent controller near-real time or non- real time hosting software or software plug-ins, such as a near-real time control application e.g., xApp or a non-real time control application e.g., rApp, or any combination thereof the adjective “open” designating support of an ORAN specification. The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an A1, F1, W1, E1 , E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment described further below in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an 0-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 810 facilitate direct or indirect connection of user equipment UE, such as by connecting UEs 812a, 812b, 812c, and 812d one or more of which may be generally referred to as UEs 812 being examples of the UE 120 to the core network 806 over one or more wireless connections.

[0119] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 800 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 800 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0120] The UEs 812 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 810 and other communication devices. Similarly, the network nodes 810 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 812 and / or with other network nodes or equipment in the telecommunication network 802 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 802.

[0121] In the depicted example, the core network 806 connects the network nodes 810 to one or more hosts, such as a host 816. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 806 includes one more core network nodes e.g., core network node 808 that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 808. Example core network nodes include functions of one or more of a Mobile Switching Center MSC, Mobility Management Entity MME, Home Subscriber Server HSS, Access and Mobility Management Function AMF, Session Management Function SMF, Authentication Server Function AUSF, Subscription Identifier De-concealing function SIDF, Unified Data Management UDM, Security Edge Protection Proxy SEPP, Network Exposure Function NEF, and / or a User Plane Function UPF.

[0122] The host 816 may be under the ownership or control of a service provider other than an operator or provider of the access network 804 and / or the telecommunication network 802, and may be operated by the service provider or on behalf of the service provider. The host 816 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0123] As a whole, the communication system 800 of Fig. 8 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications GSM; Universal Mobile Telecommunications System UMTS; Long Term Evolution LTE, and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard e.g., 6G; wireless local area network WLAN standards, such as the Institute of Electrical and Electronics Engineers IEEE 802.11 standards WiFi; and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access WiMax, Bluetooth, Z-Wave, Near Field Communication NFC ZigBee, LiFi, and / or any low-power wide-area network LPWAN standards such as LoRa and Sigfox.

[0124] In some examples, the telecommunication network 802 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 802 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 802. For example, the telecommunications network 802 may provide Ultra Reliable Low Latency Communication URLLC services to some UEs, while providing Enhanced Mobile Broadband eMBB services to other UEs, and / or Massive Machine Type Communication mMTC / Massive loT services to yet further UEs.

[0125] In some examples, the UEs 812 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 804 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 804. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of WiFi, NR New Radio and LTE, i.e. being configured for multi-radio dual connectivity MR-DC, such as E-UTRAN Evolved-UMTS Terrestrial Radio Access Network New Radio - Dual Connectivity EN-DC.

[0126] In the example, a hub 814 communicates with the access network 804 to facilitate indirect communication between one or more UEs e.g., UE 812c and / or 812d and network nodes e.g., network node 810b. In some examples, the hub 814 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 814 may be a broadband router enabling access to the core network 806 for the UEs. As another example, the hub 814 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 810, or by executable code, script, process, or other instructions in the hub 814. As another example, the hub 814 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 814 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 814 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 814 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 814 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0127] The hub 814 may have a constant / persistent or intermittent connection to the network node 810b. The hub 814 may also allow for a different communication scheme and / or schedule between the hub 814 and UEs e.g., UE 812c and / or 812d, and between the hub 814 and the core network 806. In other examples, the hub 814 is connected to the core network 806 and / or one or more UEs via a wired connection. Moreover, the hub 814 may be configured to connect to an M2M service provider over the access network 804 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 810 while still connected via the hub 814 via a wired or wireless connection. In some embodiments, the hub 814 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 810b. In other embodiments, the hub 814 may be a nondedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 810b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0128] Fig. 9 shows a UE 900 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP VoIP phone, wireless local loop phone, desktop computer, personal digital assistant PDA, wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment LEE, laptop-mounted equipment LME, smart device, wireless customer-premise equipment CPE, vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project 3GPP, including a narrow band internet of things NB-loT UE, a machine type communication MTC UE, and / or an enhanced MTC eMTC UE.

[0129] A UE may support device-to-device D2D communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication DSRC, vehicle-to-vehicle V2V, vehicle-to-infrastructure V2I, or vehicle-to- everything V2X. In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user e.g., a smart sprinkler controller. Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user e.g., a smart power meter.

[0130] The UE 900 includes processing circuitry 902 that is operatively coupled via a bus 904 to an input / output interface 906, a power source 908, a memory 910, a communication interface 912, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 9. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0131] The processing circuitry 902 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 910. The processing circuitry 902 may be implemented as one or more hardware-implemented state machines e.g., in discrete logic, field-programmable gate arrays FPGAs, application specific integrated circuits ASICs, etc.; programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor DSP, together with appropriate software; or any combination of the above. For example, the processing circuitry 902 may include multiple central processing units CPUs.

[0132] In the example, the input / output interface 906 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 900. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera e.g., a digital camera, a digital video camera, a web camera, etc., a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus USB port may be used to provide an input device and an output device.

[0133] In some embodiments, the power source 908 is structured as a battery or battery pack. Other types of power sources, such as an external power source e.g., an electricity outlet, photovoltaic device, or power cell, may be used. The power source 908 may further include power circuitry for delivering power from the power source 908 itself, and / or an external power source, to the various parts of the UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 908. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 908 to make the power suitable for the respective components of the UE 900 to which power is supplied.

[0134] The memory 910 may be or be configured to include memory such as random access memory RAM, read-only memory ROM, programmable read-only memory PROM, erasable programmable read-only memory EPROM, electrically erasable programmable read-only memory EEPROM, magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 910 includes one or more application programs 914, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 916. The memory 910 may store, for use by the UE 900, any of a variety of various operating systems or combinations of operating systems.

[0135] The memory 910 may be configured to include a number of physical drive units, such as redundant array of independent disks RAID, flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc HD-DVD optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage HDDS optical disc drive, external mini-dual in-line memory module DIMM, synchronous dynamic random access memory SDRAM, external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card UICC including one or more subscriber identity modules SIMs, such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC eUlCC, integrated UICC iUICC or a removable UICC commonly known as ‘SIM card.’ The memory 910 may allow the UE 900 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 910, which may be or comprise a device-readable storage medium. The processing circuitry 902 may be configured to communicate with an access network or other network using the communication interface 912. The communication interface 912 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 922. The communication interface 912 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication e.g., another UE or a network node in an access network. Each transceiver may include a transmitter 918 and / or a receiver 920 appropriate to provide network communications e.g., optical, electrical, frequency allocations, and so forth. Moreover, the transmitter 918 and receiver 920 may be coupled to one or more antennas e.g., antenna 922 and may share circuit components, software or firmware, or alternatively be implemented separately.

[0136] In the illustrated embodiment, communication functions of the communication interface 912 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system GPS to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access CDMA, Wideband Code Division Multiple Access WCDMA, GSM, LTE, New Radio NR, UMTS, WiMax, Ethernet, transmission control protocol / internet protocol TCP / IP, synchronous optical networking SONET, Asynchronous Transfer Mode ATM, QUIC, Hypertext Transfer Protocol HTTP, and so forth.

[0137] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 912, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic e.g., once every 15 minutes if it reports the sensed temperature, random e.g., to even out the load from reporting from several sensors, in response to a triggering event e.g., when moisture is detected an alert is sent, in response to a request e.g., a user initiated request, or a continuous stream e.g., a live video feed of a patient.

[0138] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0139] A UE, when in the form of an Internet of Things loT device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smartwatch, a fitness tracker, a head-mounted display for Augmented Reality AR or Virtual Reality VR, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle UAV, and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 900 shown in Figure 9.

[0140] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-loT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0141] In practice, any number of UEs may be used together with respect to a single use case. For example, a UE might be or be integrated in a drone and provide the drone’s speed information obtained through a speed sensor to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the UE may adjust the throttle on the drone e.g. by controlling an actuator to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0142] Fig. 10 shows a network node 1000 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points APs e.g., radio access points, base stations BSs e.g., radio base stations, Node Bs, evolved Node Bs eNBs and NR NodeBs gNBs, O-RAN nodes or components of an O-RAN node e.g., 0-Rll, 0-Dll, O-CU.

[0143] Base stations may be categorized based on the amount of coverage they provide or, stated differently, their transmit power level and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more or all parts of a distributed radio base station such as centralized digital units, distributed units e.g., in an O-RAN access node and / or remote radio units RRUs, sometimes referred to as Remote Radio Heads RRHs. Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system DAS.

[0144] Other examples of network nodes include multiple transmission point multi-TRP 5G access nodes, multi-standard radio MSR equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations BTSs, transmission points, transmission nodes, multi- cel l / multicast coordination entities MCEs, Operation and Maintenance O&M nodes, Operations Support System OSS nodes, Self-Organizing Network SON nodes, positioning nodes e.g., Evolved Serving Mobile Location Centers E-SMLCs, and / or Minimization of Drive Tests MDTs.

[0145] The network node 1000 includes a processing circuitry 1002, a memory 1004, a communication interface 1006, and a power source 1008. The network node 1000 may be composed of multiple physically separate components e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc., which may each have their own respective components. In certain scenarios in which the network node 1000 comprises multiple separate components e.g., BTS and BSC components, one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 1000 may be configured to support multiple radio access technologies RATs. In such embodiments, some components may be duplicated e.g., separate memory 1004 for different RATs and some components may be reused e.g., a same antenna 1010 may be shared by different RATs. The network node 1000 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1000, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification RFID or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1000.

[0146] The processing circuitry 1002 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1000 components, such as the memory 1004, to provide network node 1000 functionality.

[0147] In some embodiments, the processing circuitry 1002 includes a system on a chip SOC. In some embodiments, the processing circuitry 1002 includes one or more of radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry / baseband circuitry 1014. In some embodiments, the radio frequency RF transceiver circuitry 1012 and the baseband processing circuitry 1014 may be on separate chips or sets of chips, boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1012 and baseband processing circuitry 1014 may be on the same chip or set of chips, boards, or units.

[0148] The memory 1004 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory RAM, read-only memory ROM, mass storage media for example, a hard disk, removable storage media for example, a flash drive, a Compact Disk CD or a Digital Video Disk DVD, and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1002. The memory 1004 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 1002 and utilized by the network node 1000. The memory 1004 may be used to store any calculations made by the processing circuitry 1002 and / or any data received via the communication interface 1006. In some embodiments, the processing circuitry 1002 and memory 1004 is integrated.

[0149] The communication interface 1006 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1006 comprises ports / terminals 1016 to send and receive data, for example to and from a network over a wired connection. The communication interface 1006 also includes radio front-end circuitry 1018 that may be coupled to, or in certain embodiments a part of, the antenna 1010. Radio front-end circuitry 1018 comprises filters 1020 and amplifier(s) 1022. The radio front-end circuitry 1018 may be connected to an antenna 1010 and processing circuitry 1002. The radio front-end circuitry may be configured to condition signals communicated between antenna 1010 and processing circuitry 1002. The radio front-end circuitry 1018 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio frontend circuitry 1018 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1020 and / or amplifiers 1022. The radio signal may then be transmitted via the antenna 1010. Similarly, when receiving data, the antenna 1010 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1018. The digital data may be passed to the processing circuitry 1002. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0150] In certain alternative embodiments, the network node 1000 does not include separate radio front-end circuitry 1018, instead, the processing circuitry 1002 includes radio front-end circuitry and is connected to the antenna 1010. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1012 is part of the communication interface 1006. In still other embodiments, the communication interface 1006 includes one or more ports or terminals 1016, the radio front-end circuitry 1018, and the RF transceiver circuitry 1012, as part of a radio unit not shown, and the communication interface 1006 communicates with the baseband processing circuitry 1014, which is part of a digital unit not shown.

[0151] The antenna 1010 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1010 may be coupled to the radio front-end circuitry 1018 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1010 is separate from the network node 1000 and connectable to the network node 1000 through an interface or port.

[0152] The antenna 1010, communication interface 1006, and / or the processing circuitry 1002 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 1010, the communication interface 1006, and / or the processing circuitry 1002 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0153] The power source 1008 provides power to the various components of network node 1000 in a form suitable for the respective components e.g., at a voltage and current level needed for each respective component. The power source 1008 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1000 with power for performing the functionality described herein. For example, the network node 1000 may be connectable to an external power source e.g., the power grid, an electricity outlet via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1008. As a further example, the power source 1008 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0154] Embodiments of the network node 1000 may include additional components beyond those shown in Fig. 10 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1000 may include user interface equipment to allow input of information into the network node 1000 and to allow output of information from the network node 1000. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1000.

[0155] Fig. 11 is a block diagram of a host 1100, which may be an embodiment of the host 816 of Fig. 8, in accordance with various aspects described herein. As used herein, the host 1100 may be or comprise various combinations hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1100 may provide one or more services to one or more UEs.

[0156] The host 1100 includes processing circuitry 1102 that is operatively coupled via a bus 1104 to an input / output interface 1106, a network interface 1108, a power source 1110, and a memory 1112. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 14 and 10, such that the descriptions thereof are generally applicable to the corresponding components of host 1100.

[0157] The memory 1112 may include one or more computer programs including one or more host application programs 1114 and data 1116, which may include user data, e.g., data generated by a UE for the host 1100 or data generated by the host 1100 for a UE. Embodiments of the host 1100 may utilize only a subset or all of the components shown. The host application programs 1114 may be implemented in a container-based architecture and may provide support for video codecs e.g., Versatile Video Coding WC, High Efficiency Video Coding HEVC, Advanced Video Coding AVC, MPEG, VP9 and audio codecs e.g., FLAG, Advanced Audio Coding AAC, MPEG, G.711 , including transcoding for multiple different classes, types, or implementations of UEs e.g., handsets, desktop computers, wearable display systems, heads-up display systems. The host application programs 1114 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1100 may select and / or indicate a different host for over-the-top services for a UE. The host application programs 1114 may support various protocols, such as the HTTP Live Streaming HLS protocol, Real-Time Messaging Protocol RTMP, Real-Time Streaming Protocol RTSP, Dynamic Adaptive Streaming over HTTP MPEG-DASH, etc.

[0158] Fig. 12 is a block diagram illustrating a virtualization environment 1200 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines VMs implemented in one or more virtual environments 1200 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. In some embodiments, the virtualization environment 1200 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an 0-2 interface.

[0159] Application(s) 1202 which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc. are run in the virtualization environment 1200 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0160] Hardware 1204 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1206 also referred to as hypervisors or virtual machine monitors VMMs, provide VMs 1208a and 1208b one or more of which may be generally referred to as VMs 1208, and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1206 may present a virtual operating platform that appears like networking hardware to the VMs 1208.

[0161] The VMs 1208 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1206. Different embodiments of the instance of a virtual appliance 1202 may be implemented on one or more of VMs 1208, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization NFV. NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0162] In the context of NFV, a VM 1208 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1208, and that part of hardware 1204 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1208 on top of the hardware 1204 and corresponds to the application 1202.

[0163] Hardware 1204 may be implemented in a standalone network node with generic or specific components. Hardware 1204 may implement some functions via virtualization. Alternatively, hardware 1204 may be part of a larger cluster of hardware e.g. such as in a data center or CPE where many hardware nodes work together and are managed via management and orchestration 1210, which, among others, oversees lifecycle management of applications 1202. In some embodiments, hardware 1204 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1212 which may alternatively be used for communication between hardware nodes and radio units.

[0164] Fig. 13 shows a communication diagram of a host 1302 communicating via a network node 1304 with a UE 1306 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE such as a UE 812a of Fig. 8 and / or UE 900 of Figure 9 network node such as network node 810a of Fig. 8 and / or network node 1000 of Fig. 10, and host such as host 816 of Fig. 8 and / or host 1100 of Fig. 11 discussed in the preceding paragraphs will now be described with reference to Fig. 13.

[0165] Like host 1100, embodiments of host 1302 include hardware, such as a communication interface, processing circuitry, and memory. The host 1302 also includes software, which is stored in or accessible by the host 1302 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 1306 connecting via an over-the-top OTT connection 1350 extending between the UE 1306 and host 1302. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 1350.

[0166] The network node 1304 includes hardware enabling it to communicate with the host 1302 and UE 1306. A connection 1360 may be direct or pass through a core network like core network 806 of Figure 8 and / or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

[0167] The UE 1306 includes hardware and software, which is stored in or accessible by UE 1306 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 1306 with the support of the host 1302. In the host 1302, an executing host application may communicate with the executing client application via the OTT connection 1350 terminating at the UE 1306 and host 1302. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 1350 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 1350.

[0168] The OTT connection 1350 may extend via the connection 1360 between the host 1302 and the network node 1304 and via a wireless connection 1370 between the network node 1304 and the UE 1306 to provide the connection between the host 1302 and the UE 1306. The connection 1360 and wireless connection 1370, over which the OTT connection 1350 may be provided, have been drawn abstractly to illustrate the communication between the host 1302 and the UE 1306 via the network node 1304, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

[0169] As an example of transmitting data via the OTT connection 1350, in step S1 , the host 1302 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1306. In other embodiments, the user data is associated with a UE 1306 that shares data with the host 1302 without explicit human interaction. In step S2, the host 1302 initiates a transmission carrying the user data towards the UE 1306. The host 1302 may initiate the transmission responsive to a request transmitted by the UE 1306. The request may be caused by human interaction with the UE 1306 or by operation of the client application executing on the UE 1306. The transmission may pass via the network node 1304, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step S3, the network node 1304 transmits to the UE 1306 the user data that was carried in the transmission that the host 1302 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step S4, the UE 1306 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 1306 associated with the host application executed by the host 1302.

[0170] In some examples, the UE 1306 executes a client application which provides user data to the host 1302. The user data may be provided in reaction or response to the data received from the host 1302. Accordingly, in step S5, the UE 1306 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input / output interface of the UE 1306. Regardless of the specific manner in which the user data was provided, the UE 1306 initiates, in step S6, transmission of the user data towards the host 1302 via the network node 1304. In step S7, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 1304 receives user data from the UE 1306 and initiates transmission of the received user data towards the host 1302. In step S8, the host 1302 receives the user data carried in the transmission initiated by the UE 1306.

[0171] One or more of the various embodiments improve the performance of OTT services provided to the UE 1306 using the OTT connection 1350, in which the wireless connection 1370 forms the last segment.

[0172] In an example scenario, factory status information may be collected and analyzed by the host 1302. As another example, the host 1302 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 1302 may collect and analyze real-time data to assist in controlling vehicle congestion e.g., controlling traffic lights. As another example, the host 1302 may store surveillance video uploaded by a UE. As another example, the host 1302 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host 1302 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services such as compiling diagrams etc. from data collected from remote devices, or any other function of collecting, retrieving, storing, analyzing and / or transmitting data.

[0173] In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1350 between the host 1302 and UE 1306, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host 1302 and / or UE 1306. In some embodiments, sensors not shown may be deployed in or in association with other devices through which the OTT connection 1350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node 1304. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by the host 1302. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1350 while monitoring propagation times, errors, etc.

[0174] Although the computing devices described herein e.g., UEs, network nodes, hosts may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0175] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

[0176] When using the word "comprise" or “comprising” it shall be interpreted as non- limiting, i.e. meaning "consist at least of".

[0177] The embodiments herein are not limited to the preferred embodiments described above. Various alternatives, modifications and equivalents may be used.

Claims

CLAIMS1 . A method (200) performed by a core network node (130) for handling a Radio Access Technology, RAT, handover of a User Equipment, UE, (120) in a wireless communications network (100), the method comprising: obtaining (201) a first indication indicative of a first Tracking Area, TA, (151) where the UE is located; obtaining (202) a second indication indicative of an absence and / or presence of one or more RATs, for the first TA (151); and based on the first and second indication, transmitting (203) to a first radio network node (110) arranged in the first TA (151), an instruction to restrict handling of inter RAT handover of the UE (120) in the first TA (151) based on the absence and / or presence of the one or more RATs for the first TA (151).

2. The method according to claim 1 , wherein the instruction indicates to the first radio network node (110) to refrain from handling the inter RAT handover when the RAT handover is to a RAT indicated by the instruction to be absent in the first TA (151).

3. The method according to any one of claims 1-2 wherein the instruction indicates that the first radio network node (110) shall only handle inter RAT handover when the inter RAT handover only is to a RAT indicated by the instruction to be present in the first TA (151).

4. The method according to any one of claims 1-3 wherein the second indication only indicates the one or more RATs present for the first TA (151).

5. A method (300) performed by a first radio network node (110) for handling a Radio Access Technology, RAT, handover of a User Equipment, UE, (120) in a wireless communications network (100), the first radio network node (110) being arranged in a first Tracking Area, TA, (151), the method comprising: receiving (301) from a core network node (130), an instruction to restrict handling of inter RAT handover of the UE in the first TA (151) based on an absence and / or presence of one or more RATs for the first TA (151); and in response to detecting (302) a need for performing a handover of the UE to a second radio network node (112), handling (303) the handover as restricted according to the received instruction.

6. The method according to claim 5, wherein the instruction indicates to the first radio network node to refrain from handing the inter RAT handover when the inter RAT handover is to a RAT indicated by the instruction to be absent in the first TA (151).

7. The method according to any one of claims 5-6, wherein the instruction indicates that the first radio network node (110) shall only handle RAT handover when the RAT handover is to a RAT indicated by the instruction to be present in the first TA (151).

8. A core network node (130) configured to handle a Radio Access Technology, RAT, handover of a User Equipment, UE, (120) in a wireless communications network (100), the core network node (130) being configured to: obtain a first indication indicative of a first Tracking Area, TA, (151) where the UE (120) is located; obtain a second indication indicative of an absence and / or presence of one or more RATs, for the first TA (151); based on the first and second indication, transmit to a first radio network node (110) arranged in the first TA (151), an instruction to restrict handling of inter RAT handover of the UE (120) in the first TA (151) based on the absence and / or presence of the one or more RATs for the first TA (151).

9. The core network node (130) according to claim 8, wherein the instruction indicates to the first radio network node (110) to refrain from handling the inter RAT handover when the RAT handover is to a RAT indicated by the instruction to be absent in the first TA (151).

10. The core network node (130) according to any one of claims 8-9, wherein the instruction indicates that the first radio network node (110) shall only handle inter RAT handover when the inter RAT handover only is to a RAT indicated by the instruction to be present in the first TA (151).11 . The core network node (130) according to any one of claims 8-10, wherein the second indication only indicates the one or more RATs present for the first TA (151).

12. The core network node (130) according to any one of claims 8-11 , wherein the one or more RATs is GSM EDGE Radio Access Network and / or Universal Mobile Telecommunications Service Terrestrial Radio Access Network.

13. A first radio network node (110) configured to handle a Radio Access Technology, RAT, handover of a User Equipment, UE, (120) in a wireless communications network (100), the radio network node being arranged in a first Tracking Area, TA, (151) wherein the first radio network node (110) is configured to: receive from a core network node (130), an instruction to restrict handling of inter RAT handover of the UE in the first TA (151) based on an absence and / or presence of one or more RATs for the first TA (151); and in response to detecting a need for performing a handover of the UE (120) to a second radio network node (112), handle the handover as restricted according to the received instruction.

14. The first radio network node (110) according to claim 13, wherein the instruction indicates to the first radio network node (110) to refrain from handing the inter RAT handover when the inter RAT handover is to a RAT indicated by the instruction to be absent in the first TA (151).

15. The first radio network node (110) according to any one of claims 13-14, wherein the instruction indicates that the first radio network node (110) shall only handle RAT handover when the RAT handover is to a RAT indicated by the instruction to be present in the first TA (151).

16. The first radio network node (110) according to any one of claims 13-15, wherein the one or more RATs is GSM EDGE Radio Access Network and / or Universal Mobile Telecommunications Service Terrestrial Radio Access Network.

17. A computer program (630) comprising instructions, which when executed by a processor (610), causes the processor (610) to perform a method according to any one of claims 1-4.

18. A carrier (640) comprising a computer program (630) of claim 17, wherein the carrier (640) is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

19. A computer program (730) comprising instructions, which when executed by a processor (710), causes the processor (710) to perform a method according to any one of claims 5-7.

20. A carrier (740) comprising a computer program (730) of claim 19, wherein the carrier (740) is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

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