Privacy in cellular communication networks

Abstract

According to an example aspect of the present disclosure, there is provided a method, comprising receiving an indication of at least one privacy enhancing technique supported by a user equipment, determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment and applying the determined privacy enhancing technique supported by the user equipment.

Description

PRIVACY IN CELLULAR COMMUNICATION NETWORKSFIELD

[0001] Various example embodiments relate in general to cellular communication networks and more specifically, to privacy in such systems.BACKGROUND

[0002] Privacy is important in various communication networks in general, such as in cellular communication networks, like in 5G networks developed by the 3rd Generation Partnership Project, 3GPP. The 3GPP still develops 5G networks and there is a need to provide improved methods, apparatuses and computer programs for enhancing privacy in 5G networks. Such enhancements may be exploited in other cellular communication networks as well. For example, such enhancements may be exploited in 6G networks in the future.SUMMARY

[0003] According to some aspects, there is provided the subject-matter of the independent claims. Some example embodiments are defined in the dependent claims.

[0004] The scope of protection sought for various example embodiments of the disclosure is set out by the independent claims. The example embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various example embodiments of the disclosure.

[0005] According to a first aspect of the present disclosure, there is provided an apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to receive an indication of at least one privacy enhancing technique supported by a user equipment, determine, based on the indication, a privacy enhancing technique supported by the user equipment based on theat least one privacy enhancing technique supported by the user equipment and apply the determined privacy enhancing technique supported by the user equipment.

[0006] Example embodiments of the first aspect may comprise at least one feature from the following bulleted list or any combination of the following features:• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to apply the determined privacy enhancing technique by applying the determined privacy enhancing technique on a machine learning model or on data collected from the user equipment and after applying the determined privacy enhancing technique, share the machine learning model with the user equipment, or share the collected data with a network entity;• wherein the network entity is network data analytics function;• wherein the network data analytics function comprises a model training logical function;• wherein the privacy enhancing technique is a homomorphic encryption method;• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to determine the privacy enhancing technique supported by the user equipment by determining which one of multiple privacy enhancing techniques is supported by the user equipment;• wherein each of said multiple privacy enhancing techniques requires at least one requirement of a different level from the user equipment;• wherein the at least one requirement comprises at least one of a computation power requirement, a memory requirement or a capacity requirement;• wherein the apparatus is an application function or a network function, and the stored instructions further cause, when executed by the at least one processor, the apparatus at least to transmit, to an access and mobility management function, a request to provide the at least one privacy enhancing technique supported by the user equipment and receive from the access and mobility management function, based on the request, the indication of the at least one privacy enhancing technique supported by the user equipment;• wherein the apparatus is a wireless network node, and the stored instructions further cause, when executed by the at least one processor, the apparatus at least to receive the indication of the at least one privacy enhancing technique supported by the user equipment from an access and mobility function without requesting;• wherein the apparatus is another user equipment, and the stored instructions further cause, when executed by the at least one processor, the apparatus at least to receive the indication of the at least one privacy enhancing technique supported by the user equipment from the user equipment or from a core network of the user equipment.

[0007] According to a second aspect of the present disclosure, there is provided an apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to receive, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment, store the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus and transmit the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

[0008] Example embodiments of the second aspect may comprise at least one feature from the following bulleted list or any combination of the following features:• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to transmit the indication of the at least one privacy enhancing technique supported by the user equipment to a wireless network node without receiving a request;• wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to receive, from an application function or a network function, a request to provide the at least one privacy enhancing technique supported by the user equipment and transmit, based on the request, the indication of the at least one privacy enhancing technique supported by the user equipment to the application function or the network function.

[0009] According to a third aspect, there is provided a first method comprising, receiving an indication of at least one privacy enhancing technique supported by a user equipment, determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment and applying the determined privacy enhancing technique supported by the user equipment.

[0010] According to a fourth aspect, there is provided a second method comprising, receiving, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment, storing the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus and transmitting the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

[0011] According to a fifth aspect of the present disclosure, there is provided an apparatus comprising means for receiving an indication of at least one privacy enhancing technique supported by a user equipment, means for determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment and means for applying the determined privacy enhancing technique supported by the user equipment.

[0012] According to a sixth aspect of the present disclosure, there is provided an apparatus comprising means for receiving, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment, means for storing the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus and means for transmitting the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

[0013] According to some aspects of the present disclosure, there is provided a non- transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following, receiving an indication of at least one privacy enhancing technique supported by a user equipment, determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment and applying the determined privacy enhancing technique supported by the user equipment.

[0014] According to some aspects of the present disclosure, there is provided a non- transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following, receiving, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment, storing the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus and transmitting the indicationof the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

[0015] According to some aspects of the present disclosure, there is provided a computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the first or the second method. According to some aspects of the present disclosure, there is provided a computer program comprising instructions for causing an apparatus to perform at least the first or the second method.

[0016] According to some aspects of the present disclosure, there is provided a system comprising, at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the system at least to, receive an indication of at least one privacy enhancing technique supported by a user equipment, determine, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment, apply the determined privacy enhancing technique supported by the user equipment, receive, from the user equipment, the indication of the at least one privacy enhancing technique supported by the user equipment, store the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus and transmit the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

[0017] According to some aspects of the present disclosure, there is provided a system comprising, at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the system at least to, means for receiving an indication of at least one privacy enhancing technique supported by a user equipment, means for determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment, means for applying the determined privacy enhancing technique supported by the user equipment, means for receiving, from the user equipment, the indication of the at least one privacy enhancing technique supported by the user equipment, means for storing the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus and means for transmitting the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 illustrates a network scenario in accordance with at least some example embodiments;

[0019] FIG. 2 illustrates a core network in accordance with at least some example embodiments;

[0020] FIG. 3 illustrates a first signalling graph in accordance with at least some example embodiments;

[0021] FIG. 4 illustrates a second signalling graph in accordance with at least some example embodiments;

[0022] FIG. 5 illustrates an example apparatus capable of supporting at least some example embodiments;

[0023] FIG. 6 illustrates a flow graph of a first method in accordance with at least some example embodiments; and

[0024] FIG. 7 illustrates a flow graph of a second method in accordance with at least some example embodiments.EMBODIMENTS

[0025] Embodiments of the present disclosure provide privacy enhancements for cellular communication networks. More specifically, embodiments of the present disclosure enhance privacy in communication networks by enabling sharing of at least one privacy enhancing technique supported by a User Equipment, UE. One of the at least one privacy enhancing technique may be then determined and the determined privacy enhancing technique supported by the UE applied accordingly, for example by sharing a model with the UE or collecting data from the UE. Therefore, in particular privacy of UEs may be enhanced in cellular communication networks.

[0026] FIG. 1 illustrates an exemplary network scenario in accordance with at least some example embodiments. According to the example scenario of FIGURE 1, there may be acellular communication network, which comprises UE 110, wireless network node 120, and core network 130.

[0027] UE 110 may comprise, for example, a smartphone, a cellular phone, a Machine- to-Machine, M2M, node, Machine-Type Communications node, MTC, an Internet of Things, loT, node, a car telemetry unit, a laptop computer, a tablet computer or, indeed, any suitable wireless terminal. In the example of FIGURE 1, UE 110 may communicate wirelessly with wireless network node 120, or with a cell of wireless network node 120, via air interface 115.

[0028] UE 110 may be connected to wireless network node 120 via air interface 115. Air interface 115 between UE 110 and wireless network node 120 may be configured in accordance with a cellular Radio Access Technology, RAT, which UE 110 and wireless network node 120 are configured to support. Examples of cellular RATs comprise Long Term Evolution, LTE, New Radio, NR, which may also be known as fifth generation, 5G, radio access technology and MulteFire. In case of cellular RATs, wireless network node 120 may be referred to as a Base Station, BS. For example, in the context of LTE, wireless network node 120 may be referred to as eNB while in the context of NR, wireless network node 120 may be referred to as gNB. UE 110 and wireless network node 120 may be configured to, or comprise means for, operating according to at least one standard specified by the 3rd Generation Partnership Project, 3GPP.

[0029] Wireless network node 120 may be connected, directly or via at least one intermediate node, with core network 130 via interface 125. Core network 130 may be, in turn, coupled via interface 135 with another network (not shown in FIGURE 1), via which connectivity to further networks may be obtained, for example via a worldwide interconnection network. Wireless network node 120 may be connected, directly or via at least one intermediate node, with core network 130 or with another core network.

[0030] FIG. 2 illustrates a core network in accordance with at least some example embodiments. In FIGURE 2, core network node 130 may comprise Access and Mobility Management Function, AMF, 132, Unified Data Management, UDM, function 134 and at least one of Application Function, AF, and / or Network Function, NF.

[0031] AMF 132, UDM 134 and AF / NF 136 may be NFs that refer to an operational and / or a physical entity. An NF may be a specific network node or element, or a specific function or set of functions carried out by one or more entities, such as Virtual NetworkFunctions, VNFs. One physical apparatus may be configured to perform tasks of one or multiple NFs. AMF 132, UDM 134 and AF / NF 136 may be configured to, or comprise means for, operating according to at least one standard specified by the 3GPP, in a Service-Based Architecture, SBA, for example.

[0032] Privacy enhancing techniques may comprise, e.g., differential privacy, strict differential privacy, local differential privacy, global differential privacy, renyi differential privacy, pufferfish differential privacy or homomorphic encryption. In some example embodiments, a privacy enhancing technique may be referred to as a privacy preserving technique. A privacy enhancing technique may be a homomorphic encryption method.

[0033] In some example embodiments, a privacy enhancing technique might not be not an encryption method. A privacy encryption technique may enhance the privacy of the data, such that after releasing the data or a specific function of that data the privacy guarantee of the privacy encryption technique is met. (e.g. a Neural Network, NN, trained by a private data, is a function of the private data). For instance, this may be down by reducing the resolution of an image, or by adding Salt and Pepper noise to it, or by producing another image given a privacy enhancing technique random function, from the input image and release the other image.

[0034] In some example embodiments, a privacy problem may differ from a security problem. In security, there may be a legitimate entity that is supposed to be able to receive the exact data and the rest of the world might not be allowed to discover the precise data at all. In case of the privacy problem, all of the world may be getting a corrupted, noisy version of the data, which may be corrupted in a way that an individual might not be identifiable. However, the corrupted date may be used to learn some task.

[0035] In some example embodiments, each privacy enhancing technique may require at least one requirement of a different level, such as computation power, memory and capacity requirements. For each privacy enhancing technique the requirements may be different. Some privacy enhancing technique may require to down sample data which their complexity is in the order of o(n), n in the length of data. Some, like differential priority, may require samples to be taken from a Pseudo random number generator which itself may compute a complex number, and may be way higher than just down sampling.

[0036] For example, high-end UEs may support a more complex privacy enhancing technique than low-end UEs. Some UEs may support all kinds of privacy enhancing techniqueswhile some other UEs may support only some privacy enhancing techniques, but not all. Cellular communication networks, such as 5G and / or 6G networks, may exploit at least a few different privacy enhancing techniques.

[0037] However, at least one challenge is that if there is no information in the network about which privacy enhancing technique may be supported by UE 110 to protect the privacy of UE 110, or data associated with UE 110, problems may arise. For example, without knowing a privacy enhancing technique supported by UE 110, the network would not be able to effectively protect the privacy of UE 110. If a certain level of privacy is expected to be maintained regarding the data of UE 110, either at the side of UE 110 or at the network side, it may be beneficial for the network to know which privacy enhancing technique is supported by UE 110, such that configuration parameters may be set accordingly to determine the privacy enhancing technique, and level of the privacy enhancing technique.

[0038] Each privacy enhancing technique may offer different guarantees for privacy. For instance, differential privacy may offer probability of identifying an individual, or information- theoretic privacy may offer the amount of data leaked. All of these privacy guarantees may be referred to as privacy levels. To get a certain privacy guarantee, e.g., at differential privacy, one may determine how much noise is added to the data. This may be done by either reporting the added noise, or in case more complex scenarios, e.g. exponential mechanism, the report may comprise (\epsilon, \delta) as universal parameters that define the privacy level of differential privacy. Same conditions may hold for different privacy enhancing techniques, such as Renyi-differential privacy, which may have (\alpha, \epsilon).

[0039] Similar problem may arise between UE-to-UE communication, such as Device- to-Device, D2D, communication. In such cases, a first UE, like UE 110, may want to apply a privacy enhancing technique but without knowing a capability of a second UE, it might not be possible or effective to protect the privacy of the second UE. For example, protection of the second UE might not be effective considering a utility-privacy trade-off. In some example embodiments, UE-to-UE communication may be related to a joint training of a two-sided NN, which may be split between two UEs. For example, if the first UE uses k-anonymity, while the second UE uses information-theoretic privacy or differential privacy, there could be a mismatch in the dimensions of data that is exchanged between the UEs.

[0040] In some example embodiments, a Federated Learning, FL, setup may be considered, wherein UEs may be coordinated by the network. In case of the FL setup, thenetwork may train several UEs via a plurality of independent session, to enable so called collaborative learning. For that, the network may need to be able to determine which UEs are capable to support a certain type of privacy enhancing technique. For example, the network may then cluster the UEs based on their privacy enhancing technique capability to participate in the training.

[0041] In some example embodiments, model sharing and / or data collection may be enabled from the network to UE 110 and a privacy enhancing technique supported by UE 110 applied. A privacy enhancing technique may be viewed as a mathematical function or an algorithm with the private data as the input, or a function of the private data as the input and the privatised data / function as the output.

[0042] UE 110 may share at least one privacy enhancing technique supported by it with the network. For example, UE 110 may transmit an indication of the at least one privacy enhancing technique supported by it to AMF 132. In some example embodiments, UE 110 may share the at least one privacy enhancing technique supported by it with AMF 132 using Non- Access Stratum, NAS, signaling, such as NAS REGISTER signalling, or any other NAS signaling.

[0043] AMF 132 may further store the at least one privacy enhancing technique supported by UE 110 to its memory, for example in a context of UE 110. Alternatively, or in addition, AMF 132 may transmit the indication of the at least one privacy enhancing technique supported by UE 110 to UDM 134 and UDM 134 may store the at least one privacy enhancing technique supported by UE 110. In some example embodiments, core network 130, such as a 5G core network, may also expose the stored at least one privacy enhancing technique supported by UE 110 to other NFs or external AFs. For example, AMF 132 may transmit the indication of the at least one privacy enhancing technique supported by UE 110 to a RAN, e.g., to wireless network node 120, in an NG Application Protocol, NGAP, message after UE 110 has registered to the network. If wireless network node 120 wants to share the model with UE 110, wireless network node 120 may determine one of the at least one privacy enhancing technique supported by UE 110 based on the stored indication and then share the model by applying the determined privacy enhancing technique supported by UE 110.

[0044] Alternatively, or in addition, if an NF in core network 130, such as Network Data Analytics Function, NWDAF, wants to share a model with UE 110, the NF may determine one of the at least one privacy enhancing technique supported by UE 110 based on the storedindication. The NF may then share the model and apply the determined privacy enhancing technique supported by UE 110. If an external AF wants to share the model with UE 110, the external AF may retrieve the at least one privacy enhancing technique supported by UE 110 from core network 130, such as 5G core network, and determine one of the at least one privacy enhancing technique supported by UE 110 based on the stored indication. The external AF may then share the model and apply the determined privacy enhancing technique supported by UE 110.

[0045] In some example embodiments, UE-to-UE model sharing may be performed. For example, a first UE, such as UE 110, may share the at least one privacy enhancing technique supported by UE 110 with a second UE via an Application Programming Interface, API, or a service, over a D2D interface. If the second UE wants to share a model with the first UE, the second UE may retrieve the at least one privacy enhancing technique supported by UE 110 by querying the first UE, or a network of the first UE. The second UE may then determine one of the at least one privacy enhancing technique supported by UE 110 based on the stored indication, share the model and apply the determine privacy enhancing technique supported by the first UE.

[0046] FIG. 3 illustrates a first signalling graph in accordance with at least some example embodiments. On the vertical axes are disposed, from the left to the right, UE 110, wireless network node 120, AMF 132, UDM 134 and AF / NFc 136. Time advances from the top towards the bottom.

[0047] At step 302, UE 110 may share the at least one privacy enhancing technique supported by it with core network 130, e.g., with AMF 132, as a part of its registration. For example, UE 110 may transmit an indication of the at least one privacy enhancing technique supported by it to AMF 132. At step 304, AMF 132 may store to its memory the at least one privacy enhancing technique supported by UE 110. Alternatively, or in addition, AMF 132 may update UDM 134, at step 306. AMF 132 may, e.g., transmit the indication of the at least one privacy enhancing technique supported by UE 110 to UDM 134 and UDM 134 may store to its memory the at least one privacy enhancing technique supported by UE 110. At step 308, UDM 134 may transmit an acknowledgement to AMF 132, to acknowledge reception of the at least one privacy enhancing technique supported by UE 110. At step 310, AMF 132 may transmit an acceptance message to UE 110, to indicate that the registration of UE 110 has been accepted by AMF 132.

[0048] At step 312, AMF 132 may transmit the indication of the at least one privacy enhancing technique supported by UE 110 to a RAN, e.g., to wireless network node 120 without receiving a request from wireless network node 120. AMF 132 may provide the at least one privacy enhancing technique supported by UE 110 to the RAN over NGAP so that wireless network node 120 may determine, based on the indication, a privacy enhancing technique supported by UE 110. At step 314, wireless network node 120 may then apply the determined privacy enhancing technique supported by UE 110 based on the at least one privacy enhancing technique supported by UE 110. That is, wireless network node 120 may be an apparatus performing determination of the privacy enhancing technique supported by UE 110 and applying the determined privacy enhancing technique supported by UE 110. For example, wireless network node 120 may apply the determined privacy enhancing technique supported by UE 110 by sharing a model with UE 110 or collecting data from UE 110.

[0049] At step 316, AF / NF 136 may transmit to UDM 134 a request to provide the at least one privacy enhancing technique supported by UE 110. At step 318, UDM 134 may transmit, based on the request, the indication of the at least one privacy enhancing technique supported by UE 110. Alternatively, AF / NF 136 may transmit, at step 320, the request to provide the at least one privacy enhancing technique supported by UE 110 to AMF 132. At step 322, AMF 132 may transmit, based on the request, the indication of the at least one privacy enhancing technique supported by UE 110.

[0050] At step 324, AF / NF 136 may then determine, based on the indication, a privacy enhancing technique supported by UE 110 based on the at least one privacy enhancing technique supported by UE 110 and apply the determined privacy enhancing technique supported by UE 110. NF 136 may apply the determined privacy enhancing technique supported by UE 110 by sharing a model with UE 110 or collecting data from UE 110. That is, AF / NF 136 may be an apparatus performing determination of the privacy enhancing technique supported by UE 110 and applying the determined privacy enhancing technique supported by UE 110.

[0051] For example, if an NF in core network 130, such as an NWDAF wants to share a model with UE 110, the NF may determine the privacy enhancing technique supported by UE 110 based on the indication and apply the determined privacy enhancing technique supported by UE 110 by sharing a model with UE 110 or collecting data from UE 110. If an external NF (outside of core network 130) wants to share a model with UE 110, the external NF may retrievethe indication of the at least one privacy enhancing technique supported by UE 110 similarly from core network 130, perform determination of a privacy enhancing technique supported by UE 110 based on the at least one privacy enhancing technique supported by UE 110. The external NF may apply the determined privacy enhancing technique supported by UE 110 by sharing a model with UE 110 or collecting data from UE 110.

[0052] FIG. 4 illustrates a second signalling graph in accordance with at least some example embodiments. On the vertical axes are disposed, from the left to the right, first UE 110, second UE 112, third UE 114 and core network 130. Time advances from the top towards the bottom. In some example embodiments, first UE 110 may be referred to as a UE and second UE 112 may be referred to as another UE.

[0053] At step 402, first UE 110 may transmit the indication of the at least one privacy enhancing technique supported by UE 110 to core network 130, e.g., to AMF 132, as a part of registration of first UE 110. AMF 132 may further store the indication to its memory.

[0054] At step 404, second UE 112 may transmit a request to first UE 110, to request the at least one privacy enhancing technique supported by first UE 110. At step 406, first UE 110 may provide to second UE 112, based on the request, the at least one privacy enhancing technique supported by first UE 110. For example, first UE 110 may provide an API over a D2D interface and second UE 112 may then retrieve the at least one privacy enhancing technique supported by UE 110 using the API.

[0055] Alternatively, second UE 112 may download the at least one privacy enhancing technique supported by UE 110 from core network 130. At step 408, second UE 112 may transmit a request to core network 130, e.g., to AMF 132, to request the at least one privacy enhancing technique supported by first UE 110. At step 410, the at least one privacy enhancing technique supported by first UE 110 may be provided from core network 130 to second UE 112, based on the request. Alternatively, first UE 110 may broadcast, at step 412, the at least one privacy enhancing technique supported by it over a sidelink.

[0056] At step 414, second UE 112 may determine, based on the indication, a privacy enhancing technique supported by UE 110 based on the at least one privacy enhancing technique supported by UE 110. Second UE 112 may then apply the determined privacy enhancing technique supported by UE 110. Second UE 112 may apply the determined privacy enhancing technique supported by UE 110 by sharing a model with UE 110 or collecting datafrom UE 110. That is, second UE 112 may be an apparatus performing determination of the privacy enhancing technique supported by UE 110 and applying the determined privacy enhancing technique supported by UE 110.

[0057] The model, to which the determined privacy enhancing technique supported by UE 110 may be applied, may be a Machine Learning, ML, model. Alternatively, or in addition, the determined privacy enhancing technique supported by UE 110 may be applied to training data or any other kind of metadata needed for ML training. For example, the determined privacy enhancing technique may be applied by applying the determined privacy enhancing technique on an ML model or on data collected from UE 110. After applying the determined privacy enhancing technique, the ML model may be shared with UE 110, or the collected data may be shared with a network entity. The network entity may be any access node (e.g., gNB), any core network function (e.g., NWDAF), AF, management function (Operations, Administration and Maintenance, 0AM, area) or any other UE (D2D communication). In some example embodiments, the NWDAF may comprise a model training logical function.

[0058] In some example embodiments, the privacy enhancing technique supported by UE 110 may be determined by determining which of multiple privacy enhancing techniques is supported by UE. For example, there may be a few different privacy enhancing techniques available, possibly specified in at least one 3GPP standard, but UE 110 may support only one privacy enhancing technique, not more than one privacy enhancing technique. That is, UE 110 may be capable of supporting one privacy enhancing technique of said multiple privacy enhancing techniques.

[0059] In some example embodiments, UE 110 may support homographic encryption and strict differential privacy. UE 110 would thus support 2 privacy enhancing techniques. Second UE 112, wireless network node 120 and / or AF / NF 136 may determine that either of the 2 privacy enhancing techniques, supported by UE 110, may be applied towards UE 110. For example, second UE 112, wireless network node 120 and / or AF / NF 136 may determine to apply homomorphic encryption. The determined privacy enhancing technique supported by UE 110. In such a case, second UE 112, wireless network node 120 and / or AF / NF 136 may apply the determined privacy enhancing technique supported by UE 110 by encrypting the ML model before sharing it with UE 110.

[0060] FIG. 5 illustrates an example apparatus capable of supporting at least some example embodiments. Illustrated is device 500, which may comprise, for example, second UE112, wireless network node 120, AMF 132 or AF / NF 136, or a device controlling functioning thereof. Comprised in device 500 is processor 510, which may comprise, for example, a single- or multi-core processor wherein a single-core processor comprises one processing core and a multi-core processor comprises more than one processing core. Processor 510 may comprise, in general, a control device. Processor 510 may comprise more than one processor. Processor 510 may be a control device. Processor 510 may comprise at least one Application-Specific Integrated Circuit, ASIC. Processor 510 may comprise at least one Field- Programmable Gate Array, FPGA. Processor 510 may comprise an Intel Xeon processor for example. Processor 510 may be means for performing method steps in device 500, such as determining, causing transmitting and causing receiving. Processor 510 may be configured, at least in part by computer instructions, to perform actions.

[0061] A processor may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with example embodiments described herein. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a network function, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0062] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0063] Device 500 may comprise memory 520. Memory 520 may comprise randomaccess memory and / or permanent memory. Memory 520 may comprise at least one RAM chip. Memory 520 may comprise solid-state, magnetic, optical and / or holographic memory, for example. Memory 520 may be at least in part accessible to processor 510. Memory 520 may be at least in part comprised in processor 510. Memory 520 may be means for storing information. Memory 520 may comprise computer instructions that processor 510 is configured to execute. When computer instructions configured to cause processor 510 to perform certain actions are stored in memory 520, and device 500 overall is configured to run under the direction of processor 510 using computer instructions from memory 520, processor 510 and / or its at least one processing core may be considered to be configured to perform said certain actions. Memory 520 may be at least in part comprised in processor 510. Memory 520 may be at least in part external to device 500 but accessible to device 500.

[0064] Device 500 may comprise a transmitter 530. Device 500 may comprise a receiver540. Transmitter 530 and receiver 540 may be configured to transmit and receive, respectively, information in accordance with at least one cellular standard, such as a standard defined by the 3rd Generation Partnership Project, 3GPP. Transmitter 530 may comprise more than one transmitter. Receiver 540 may comprise more than one receiver. Transmitter 530 and / or receiver 540 may be configured to operate in accordance with Global System for Mobile communication, GSM, Wideband Code Division Multiple Access, WCDMA, Long Term Evolution, LTE, and / or 5G standards, for example.

[0065] Device 500 may comprise User Interface, UI, 550. UI 550 may comprise at least one of a display, a keyboard, a touchscreen, a vibrator arranged to signal to a user by causing device 500 to vibrate, a speakeror a microphone. A user may be able to operate device 500 via UI 550, for example to configure device 500 and / or functions it runs.

[0066] Processor 510 may be furnished with a transmitter arranged to output information from processor 510, via electrical leads internal to device 500, to other devices comprised in device 500. Such a transmitter may comprise a serial bus transmitter arranged to, for example, output information via at least one electrical lead to memory 520 for storage therein. Alternatively to a serial bus, the transmitter may comprise a parallel bus transmitter. Likewise processor 510 may comprise a receiver arranged to receive information in processor 510, via electrical leads internal to device 500, from other devices comprised in device 500. Such a receiver may comprise a serial bus receiver arranged to, for example, receive information viaat least one electrical lead from receiver 540 for processing in processor 510. Alternatively to a serial bus, the receiver may comprise a parallel bus receiver.

[0067] Device 500 may comprise further devices not illustrated in FIG. 5. In some example embodiments, device 500 lacks at least one device described above. For example, device 500 may not have UI 550.

[0068] Processor 510, memory 520, transmitter 530, receiver 540 and / or UI 550 may be interconnected by electrical leads internal to device 500 in a multitude of different ways. For example, each of the aforementioned devices may be separately connected to a master bus internal to device 500, to allow for the devices to exchange information. However, as the skilled person will appreciate, this is only one example and depending on the example embodiment various ways of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the present disclosure.

[0069] FIG. 6 is a flow graph of a first method in accordance with at least some embodiments. The first method may be performed by at least one second UE 112, wireless network node 120 and AF / NF 136.

[0070] The first method may comprise, at step 610, receiving an indication of at least one privacy enhancing technique supported by a user equipment. The first method may also comprise, at step 620, determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment. Finally, the first method may comprise, at step 630, applying the determined privacy enhancing technique supported by the user equipment.

[0071] FIG. 7 is a flow graph of a second method in accordance with at least some embodiments. The second method may be performed by AMF 132.

[0072] The second method may comprise, at step 710, receiving, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment. The second method may also comprise, at step 720, storing the indication of the at least one privacy enhancing technique supported by the user equipment to at least one memory of an apparatus. Finally, the second method may comprise, at step 730, transmitting the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

[0073] It is to be understood that the embodiments disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0074] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Where reference is made to a numerical value using a term such as, for example, about or substantially, the exact numerical value is also disclosed.

[0075] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and examples may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations.

[0076] In an example embodiment, an apparatus, like second UE 112, wireless network node 120, AMF 132 or AF / NF 136, or a device controlling functioning thereof, may comprise means for carrying out the embodiments described above and any combination thereof.

[0077] In an example embodiment, a computer program comprising instructions which, when the program is executed by an apparatus, may cause the apparatus to carry out the first method or the second method.in accordance with the embodiments described above and any combination thereof. In an example embodiment, a computer program product, embodied on a non-transitory computer readable medium, may be configured to control a processor to perform a process comprising the embodiments described above and any combination thereof.

[0078] In an example embodiment, an apparatus, like second UE 112, wireless network node 120, AMF 132 or AF / NF 136, or a device controlling functioning thereof, may comprise at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform the embodiments described above and any combination thereof.

[0079] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the preceding description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the disclosure can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well- known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.

[0080] While the forgoing examples are illustrative of the principles of the embodiments in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the disclosure. Accordingly, it is not intended that the disclosure be limited, except as by the claims set forth below.

[0081] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", that is, a singular form, throughout this document does not exclude a plurality.

[0082] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.INDUSTRIAE APPEICABIEITY

[0083] At least some example embodiments find industrial application in communication networks, for example in cellular communication networks, such as 3GPP networks.ACRONYMS LIST3GPP 3rdGeneration Partnership ProjectAF Application FunctionAMF Access and Mobility Management FunctionAPI Application Programming InterfaceBS Base StationD2D Device-to-DeviceFL Federated Learning loT Internet of ThingsLTE Long Term EvolutionM2M Machine-to-MachineML Machine LearningMTC Machine-Type CommunicationsNAS Non-Access StratumNF Network FunctionNGAP NG Application ProtocolNR New RadioNWDAF Network Data Analytics Function0AM Operations, Administration and MaintenanceRAT Radio Access TechnologySBA Service-Based ArchitectureUE User EquipmentUDM Unified Data ManagementVNF Virtual Network FunctionREFERENCE SIGNS LIST

Claims

Claims:

1. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: receive an indication of at least one privacy enhancing technique supported by a user equipment; determine, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment; and apply the determined privacy enhancing technique supported by the user equipment.

2. The apparatus according to claim 1, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to: apply the determined privacy enhancing technique by applying the determined privacy enhancing technique on a machine learning model or on data collected from the user equipment; and after applying the determined privacy enhancing technique, share the machine learning model with the user equipment, or share the collected data with a network entity.

3. The apparatus according to claim 2, wherein the network entity is network data analytics function.

4. The apparatus according to claim 3, wherein the network data analytics function comprises a model training logical function.

5. The apparatus according to any of the preceding claims, wherein the privacy enhancing technique is a homomorphic encryption method.

6. The apparatus according to any of the preceding claims, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to:determine the privacy enhancing technique supported by the user equipment by determining which one of multiple privacy enhancing techniques is supported by the user equipment.

7. The apparatus according to claim 6, wherein each of said multiple privacy enhancing techniques requires at least one requirement of a different level from the user equipment.

8. The apparatus according to claim 7, wherein the at least one requirement comprises at least one of a computation power requirement, a memory requirement or a capacity requirement.

9. The apparatus according to any of the preceding claims, wherein the apparatus is an application function or a network function, and the stored instructions further cause, when executed by the at least one processor, the apparatus at least to: transmit, to an access and mobility management function, a request to provide the at least one privacy enhancing technique supported by the user equipment; and receive from the access and mobility management function, based on the request, the indication of the at least one privacy enhancing technique supported by the user equipment.

10. The apparatus according to any of claims 1 to 8, wherein the apparatus is a wireless network node, and the stored instructions further cause, when executed by the at least one processor, the apparatus at least to: receive the indication of the at least one privacy enhancing technique supported by the user equipment from an access and mobility function without requesting.

11. The apparatus according to any of claims 1 to 8, wherein the apparatus is another user equipment, and the stored instructions further cause, when executed by the at least one processor, the apparatus at least to: receive the indication of the at least one privacy enhancing technique supported by the user equipment from the user equipment or from a core network of the user equipment.

12. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:receive, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment; store the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus; and transmit the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

13. The apparatus according to claim 12, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to: transmit the indication of the at least one privacy enhancing technique supported by the user equipment to a wireless network node without receiving a request.

14. The apparatus according to claim 12 or claim 13, wherein the stored instructions further cause, when executed by the at least one processor, the apparatus at least to: receive, from an application function or a network function, a request to provide the at least one privacy enhancing technique supported by the user equipment; and transmit, based on the request, the indication of the at least one privacy enhancing technique supported by the user equipment to the application function or the network function.

15. A method, comprising: receiving an indication of at least one privacy enhancing technique supported by a user equipment; determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment; and applying the determined privacy enhancing technique supported by the user equipment.

16. A method, comprising: receiving, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment; storing the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus; andtransmitting the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

17. An apparatus comprising: means for receiving an indication of at least one privacy enhancing technique supported by a user equipment; means for determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment; and means for applying the determined privacy enhancing technique supported by the user equipment.

18. An apparatus comprising: means for receiving, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment; means for storing the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus; and means for transmitting the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

19. A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving an indication of at least one privacy enhancing technique supported by a user equipment; determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment; and applying the determined privacy enhancing technique supported by the user equipment.

20. A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a user equipment, an indication of at least one privacy enhancing technique supported by the user equipment;storing the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus; and transmitting the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

21. A computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method of claim 15 or 16.

22. A computer program comprising instructions for causing an apparatus to perform at least the method of claim 15 or 16.

23. A system comprising: at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the system at least to: receive an indication of at least one privacy enhancing technique supported by a user equipment; determine, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment; apply the determined privacy enhancing technique supported by the user equipment; receive, from the user equipment, the indication of the at least one privacy enhancing technique supported by the user equipment; store the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus; and transmit the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

24. A system comprising: means for receiving an indication of at least one privacy enhancing technique supported by a user equipment; means for determining, based on the indication, a privacy enhancing technique supported by the user equipment based on the at least one privacy enhancing technique supported by the user equipment;means for applying the determined privacy enhancing technique supported by the user equipment; means for receiving, from the user equipment, the indication of the at least one privacy enhancing technique supported by the user equipment; means for storing the indication of the at least one privacy enhancing technique supported by the user equipment to the at least one memory of the apparatus; and means for transmitting the indication of the at least one privacy enhancing technique supported by the user equipment to a unified data management function.

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