Patent Application
20200327251
The present invention relates to media content privacy control, and in particular to controlling access to image and video media content.
Personal media content, such as images and videos, is increasingly shared and distributed via various services, such as social media applications. Each platform, service or application typically has its own privacy control mechanism. A user can typically set users and groups of users to whom his/her personal content is available, e.g. a list of friends, except users x and y. The privacy control mechanisms may be oversimplified or cumbersome. The services typically update their policies, requiring constant attention or revision by the user.
Further, users often do not know if or how their personal media content can be used for other purposes, such as further analysed to offer personalized advertisements or develop computer-vision algorithms. Users often cannot control, or have very limited chances to control such usage of their personal media content. This is generally set by terms and conditions of the service, which in many cases are difficult to read and remember.
The invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims.
According to a first aspect of the present invention, there is provided a method, comprising: generating, based on source media content, a media vector comprising one or more privacy-controlled components, wherein each component is a partially modified version of the source media content such that at least some different privacy-controlled visual media content parts of the source media content are removed, substituted or hidden at different privacy-controlled components, and assigning for each of the components privacy control information.
According to a second aspect of the present invention, there is provided a method, comprising: receiving, by a media content user apparatus privacy control information, wherein the privacy control information is associated with one or more privacy-controlled components of a media vector, each privacy-controlled component representing a partially modified version of associated source media content, and accessing at least one of the components of the media vector on the basis of the privacy control information.
According to a third aspect, there is provided an apparatus, comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to: generate, based on source media content, a media vector comprising one or more privacy-controlled components, wherein each component is a partially modified version of the source media content such that at least some different privacy-controlled visual media content parts of the source media content are removed, substituted or hidden at different privacy-controlled components, and assign for each of the components privacy control information.
According to a fourth aspect, there is provided an apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to: receive privacy control information, wherein the privacy control information is associated with one or more privacy-controlled components of a media vector, each privacy-controlled component representing a partially modified version of associated source media content, and access at least one of the components of the media vector on the basis of the privacy control information.
According to a fifth aspect, there is provided a computer program product or a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least: generate, based on source media content, a media vector comprising one or more privacy-controlled components, wherein each component is a partially modified version of the source media content such that at least some different privacy-controlled visual media content parts of the source media content are removed, substituted or hidden at different privacy-controlled components, and assign for each of the components privacy control information.
According to a sixth aspect, there is provided a computer program product or a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least: receive privacy control information, wherein the privacy control information is associated with one or more privacy-controlled components of a media vector, each privacy-controlled component representing a partially modified version of associated source media content, and access at least one of the components of the media vector on the basis of the privacy control information.
According to an embodiment, the privacy control information is provided to or received from a distributed ledger for controlling access to one or more of the components of the media vector.
According to an embodiment, the accessing at least one of the components comprises: sending a request for at least one of the components, receiving a signed token indicating at least one of the components that are allowed to be delivered to the media content user, sending the signed token to an entity storing and/or controlling access to the media vector, receiving the at least one of the components from the entity, and causing decoding of the at least one of the components or sending of the at least one of the components for a media player device.
There are now provided methods and apparatuses facilitating a user-centric, cross-platform and decentralized privacy control framework for personal media content, particularly for personal video and image content. Different versions of source media content are generated, such that each version or component may reveal a different level of privacy-controlled visual media content parts of the source media content. A media vector comprising different privacy controlled components may thus be generated, wherein each component may be assigned with specific privacy control information, which may form a privacy array. The privacy control information is stored and managed in a secure and trustworthy manner, in some embodiments by storing and transferring the media vector and the privacy array in encrypted and integrity-protected form for users owning the privacy control information and the media content and entities authorized to use the media content, such as users playing the media content. On the basis of the privacy control information, relevant media vectors may be provided to legitimate authenticated media content users, such as users' media players.
A distributed ledger may be applied for automatically controlling usage of user's media content by various service providers according to user's preferences. A distributed ledger can be considered a general database synchronized between many parties, which, at successive time instances, comprises successive states of consensus about a particular matter, here media content privacy control information. Such states may be reached by the many parties, typically nodes in a peer-to-peer (P2P) network, following a decentralized consensus algorithm. In general, this provides an agreement between the nodes without assuming trust between them. Different service providers may oversee in the distributed ledger that every participant handling personal media content is playing by the rules set by the user.
A media vector comprising one or more privacy-controlled components is generated 100 based on source media content. The media vector refers generally to a collection of at least the privacy-controlled components and may be structured in various forms. Each privacy-controlled component is a partially modified version of the source media content. Privacy control information is assigned 110 for each of the components. The privacy control information is provided 120 or stored for controlling access to one or more of the components of the media vector. The privacy control information may thus be sent for storage in encrypted form to a database for controlling access to one or more of the components of the media vector. In some embodiments, the privacy control information is sent 120 to a distributed ledger. However, although references are made below particularly to use of distributed ledger, it is to be appreciated that the privacy control information may be made available for media content users in various other ways, such as sending the privacy control information, possibly with the media vector, to a further device controlling access to the media vector. Such system may comprise one more databases and security leveraging certification entities, mutual authentication between parties, transaction and content encryption.
A media content user apparatus receives 200 privacy control information which in some embodiments is stored in a distributed ledger. The privacy control information is associated with one or more privacy-controlled components of a media vector, each privacy-controlled component representing a partially modified version of associated source media content. The components may provide different levels of privacy-controlled visual media content parts of the source media content for presentation and each component may be assigned with specific privacy control information. At least one of the components of the media vector is accessed 210 on the basis of the privacy control information.
The present features facilitate to achieve a multi-level, user-centric, and automatic way of dealing with privacy and usage of personal media content, such as images and video. Personal media content may thus be post-processed to produce 100 a media vector with a number of different privacy-controlled components. The privacy-controlled components of the media vector can be understood as different copies of the visual media content in which different elements are removed or substituted, e.g. substituting people with black silhouettes. The privacy control information assigned 110 for each component of the media vector may comprise privacy-related information and instructions that may also be referred to as a privacy array. Privacy arrays may be stored 120 in the distributed ledger or other suitable storage for access 200 by service providers that make use of personal visual content to automatically display it differently depending on applied privacy context.
The CPA 14 may be connected to a distributed network 20. The distributed network may comprise a number of nodes 22. The CPA 14 may operate as a node in the network 20, or the CPA 14 may connect a node on the network 20 so that the latter operates on its behalf.
The privacy control information may be stored in a distributed ledger stored at least in part of nodes 22 of the distributed network 20. A media content user apparatus 30, which may be also referred to as a content receiving apparatus (CRA), may receive the privacy control information stored in the distributed ledger and carry out the features illustrated in connection with
The media vector may be stored in a media content storage 32, such as a media server connected by the CRA 30. The CRA may directly further use the media content according to the privacy control information, such as display image content by a user device or analyze or modify the media content. In some embodiments, the CRA is an intermediate device and provides at least part of the media content, according to the privacy control information, to further device(s) 34. For example, the CRA may be a media content service provider server receiving requests from user devices and providing allowed media content components to authorized requesting user devices. There may be also other devices 40 capable of at least accessing the distributed ledger.
The devices 10, 12, 14, 30, 34, 40 may comprise corporate, authority, and/or user devices, such as a server, a desktop/tablet/laptop computer, smartphone, set-top box or other suitable electronic device. The system may comprise an administrator or management node, a hub, relay or other kind of intermediate device (not shown) for connecting a node to further networks or services, such as another distributed or centralized computing system or a cloud service. The nodes are mutually addressable in a suitable way, for example, they may be connected to an internet protocol, IP, network. Messages released into the IP network with a recipient address are routed by the network to the recipient node identified by the recipient address. IP is not the only suitable networking technology used, for example, other peer-to-peer networking models are also suitable.
In some embodiments, the distributed network 20 is a blockchain network and the nodes 14, 22, 30, 40 operate as blockchain (BC) nodes and store local blockchain database. The distributed ledger is a blockchain ledger and the privacy control information is provided 120 to the blockchain ledger in response to validation of a blockchain transaction comprising the assigned privacy control information.
Blockchain state information shared by the nodes may store all the transactions and history carried out in the network 20, also regarding the privacy control information of media vector components. The blockchain state information is stored in or as the blockchain ledger. Each node may comprise the ledger whose content is in sync with other ledgers. The nodes may validate and commit transactions in order to reach consensus. Each node may have their own copy of the ledger which is in some embodiments permission-controlled, so participants see only appropriate transactions.
Changes in resource ownership in the blockchain 20 take the form of blockchain transactions secured by strong cryptography. A blockchain transaction may comprise an identifier of a new owner, that is the recipient, of the resource, together with a cryptographic signature of the previous owner, that is the sender, such that malicious attackers cannot re-assign resources they do not own. Application of blockchain technology and the ledger enable a way to track the unique history of transactions by the individual nodes in the network.
The CPA 14 may provide 120 signed blockchain transactions to the blockchain ledger whenever it generates privacy control information. To establish a next block, the transactions are broadcast into the blockchain network. Broadcasting here refers to a dissemination method suitable for the context, which will cause the transactions to be communicated to the nodes of the network in general. Reaching each and every node with each and every transaction is not strictly necessary.
A node establishing the next block may be known as a miner node. A miner node may compile a set of transactions, which it receives from the broadcasts, for the next block, and search for a proof-of-work code that covers all the transactions in the set of transactions for the next block. For example, the proof-of-work code may be a numerical value, with which the contents of the next block, that is, the set of transactions, hashes to a value that is less than a threshold. More generally, there may be a target area of an output space of a hash function, wherein the target space need not be in the low end of the target space. The smaller the target area is, the more difficult it is to discover the proof-of-work. Once a miner discovers the proof-of-work, it can publish the block, which other nodes of the system will then add to the block chain as the new most recent established block.
In case the miner node discovers a proof-or-work based on an incomplete set of transactions, for example if some transactions did not reach the miner node, other nodes in the network will not accept the block into the blockchain, and it will be excluded from a consensus version of the blockchain in the system.
Since an output of a hash function is a pseudorandom function of the input, the set of transactions, hashed by itself, produces a hash value that is essentially randomly placed in the output space of the hash function. The set of transactions may be completely or representatively used as input to the hash function. Modifying the input with a candidate proof-of-work code, which may be known as a nonce, will produce a new hash value, which again is essentially randomly placed in the output space of the hash function. The modification may be as slight as a single bit. Therefore, searching for the correct proof-of-work code, which satisfies a pre-agreed criterion concerning its location in the output space of the hash function, requires repeatedly deriving a hash value with a different candidate proof-of-work code modifying the input to the hash function. Once a proof-of-work code that, with the transactions, produces a hash value in the target area of the output space of the hash function is found, the block is ready. A completed block may be distributed to the system to establish it in the blockchain. Although discussed above in terms of proof-of-work, in some embodiments a proof-of-stake may be used instead of, or additionally to, a proof-of-work. In a proof-of-stake based system, a new block is accepted once a sufficient fraction of resources are proven as owned by nodes ready to accept the new block version.
Once a new block is established, the blockchain becomes longer. A transaction is considered the more reliable, the larger the number of blocks established since the block where the transaction is comprised. This is since transactions are hashed into the chain of blocks, and discrepancies in the block chain are resolved as the block chain gets longer. In each next block in the sequence, a hash of the previous block may be included along with the transactions, attaching the blocks to each other to form the chain. Hashes linking the blocks together to form a chain may be referred to as Merkle hashes. Maliciously modifying a transaction in a block far down the chain would involve re-doing the work of finding proofs for all subsequent blocks, since the input to the hash function for the block comprising the transaction would be changed, causing the resulting hash value, with the proof in that block, to no longer be disposed in the desired area in the output space of the hash function.
With reference to
At least some different privacy-controlled visual media content parts of the source media content 402 may be removed, substituted or hidden at different privacy-controlled components 404, 406. In some embodiments, the source media content comprises image data. The image data is thus analysed for detecting privacy-sensitive image elements. Regions of image data comprising privacy-sensitive elements are classified and assigned privacy levels according to content owner's preferences. Privacy-sensitive image elements are included or avoided in the privacy-controlled components on the basis of the assigned privacy levels.
In some embodiments, the privacy control information for each of the components in the media vector 400 is stored in a privacy array.
As illustrated in
A blockchain transaction comprising the privacy control information, such as the privacy array 600, may be a public transaction. Such transaction record comprises the privacy control information and a hash pointer to previous block of the chain. The record may comprise also further information element(s), such as timestamp.
The detection 810 and tracking of privacy-sensitive elements in a received 800 source video sequence may be carried out by a specific module, which can be automatic or semi-automatic. The aim of this module is detecting and classifying regions of the image that contain sensitive elements, e.g. faces of users, or private home contents. This can be done using an image recognition technology, in some embodiments based on deep convolutional neural networks.
In some embodiments, a list of such privacy-sensitive elements pre-defines target labels for the image recognition algorithms and default sensitivity. For example, such list may define:
The output of this first module may include the source video sequence and a sequence of bounding silhouettes identifying the privacy-sensitive elements in each video frame and their positions.
A second module may receive the output above as input and automatically decide 820 which areas of the image need to be protected. This may be performed based on the location of recording and/or according to user's privacy preferences, for example. For example, the user may have decided to protect only some people, only children, etc. In the preferred embodiment a predefined set of features will be protected, defining a hierarchy of privacy levels.
The output of the second module may be the source video sequence, the sequence of silhouettes that need to be protected, and their assigned privacy levels. For example, the sensitive content may be defined as follows:
Finally, a third module may generate 830 the video vector and privacy array. According to an example embodiment, this may be performed by the following steps 1-4:
1. Time segmentation. It segments the video in periods with common privacy properties. This allows to produce a single version of the video in parts where there are no privacy concerns (e.g. there are no people in the screen for a while), and personalized versions for parts where there are privacy concerns. A first coarse approach, without loss of generality, would be considering a single time period covering the whole video. In any case, for each period, the following process may be applied:
2. Generation of the ABL, which can be thought of as the video sequence without any elements of the sensitive content list. This may be the first component of the video vector.
3. Generation of increasingly revealing layers, each of them becoming parallel component of the video vector. For example, this may involve using:
If the content is to be delivered over the internet, versions of steps 2 and 3 can be generated at different resolutions and bit rates, for their use in HTTP Adaptive Streaming protocols.
4. Generation of the privacy array, which may be performed as further illustrated below.
As illustrated in connection with
The privacy array may be stored in the distributed ledger and uniquely linked to the original source video sequence by the “Hash[original sequence]” (first element of the last row of the privacy array). Moreover, it can be found by using the hash of the least sensitive version of the video “Hash[anonymized base layer video sequence]”, which may be commonly shared.
The detection, filtering and privacy array generating modules can be owned by the private user themselves, or run as part of a third-party cloud service.
The distributed ledger offers a decentralized, auditable, and tamper-proof registry of privacy permissions. In some embodiments, the miner nodes run a distributed ledger client together with a video player application. This may include private users as well as service providers, such as social media service providers or video sharing service providers, which provide video playback through applets embedded on their apps or websites. However, a “lite” version of the video player can have the same functionality in terms of only reproducing video according to the agreed privacy settings and not participate in the consensus algorithm of the distributed ledger.
A smart contract may be applied to control access to the media vector on the basis of the assigned privacy control information. The smart contract may issue tokens for verified media content requesting entities, each token indicating media components allowed to be provided to a media content requesting entity.
Step 210 may comprise sending a request for media vector component(s) to the distributed ledger. A signed token may be received, indicating at least one of the components that are allowed to be delivered to the media content user. The signed token may be sent to an entity storing and/or controlling access to the media vector, such as an entity controlling the storage 32. Allowed component(s) are received from the entity and they may be decoded for playback or sent to another device 34, such as for a media player application of a requesting user device.
A request for media vector components and/or a message to the entity comprising the signed token may be signed with a private key associated with the media content user.
The signature may be retrieved from memory or generated for the document by a secret key associated to the signing apparatus. The secret key may be a device-specific secret key, or in some embodiments a private cryptography key of an authorized user provided to the apparatus, for example. Each device may be provided with a public-private key pair at manufacture. The private key resides on the certifying device's secured element, such that it cannot be tampered with and the private key cannot be stolen. Moreover, the secure element also holds the hashing and signing logic.
Sensitive media content that may be stored in a third-party cloud or other service may be encrypted with the owner's secret key, such that no one can access it unless explicit permission is given by the user. The media vector component(s) may be received 200 in encrypted form and decrypted with a private key associated with the media content user. To share media content, the owner may decrypt the data and re-encrypt it with the recipient's public key. This it can be ensured that the privacy settings cannot be disobeyed accidentally. An example process of video encryption and decryption will be further explained below.
A potential embodiment for the playout is using MPEG Dynamic Adaptive Streaming over HTTP (DASH) as video distribution format. Thus, each video period with common privacy settings may be signalled as a DASH period. In each DASH period, there will be as many video Adaptation Sets as privacy options, e.g. one for anonymous content, one for friends, one for game buddies, etc.
The Adaptation Set may contain all content elements or representations required by a recipient to play the video according to the corresponding privacy settings and information required to decrypt the video content.
All representations are encrypted with the recipient's public key, except for the ABL. Alternatively, each Representation can be encrypted with an individual random key, which may be common for all recipients and referred to as a Content Key. The Content Keys may be encrypted with the recipient's public key using, for instance, MPEG Common Encryption (CENC) protocol.
The information required to decrypt the video content may be stored in a third party server. In an embodiment, the following procedure is applied for accessing encrypted media vector:
In an alternative embodiment, the video vector may be stored as unencrypted in a private server of the video producer or owner. In such case the protocol would be similar, except for step 4, which may be replaced by:
In some embodiments there may be also other roles than a content (and privacy control information) provider 14 and a content (and privacy control information) user or receiver 30, 34. There may be third parties 40 that may be able to modify at least some portion of the privacy control information. In some embodiments, an entity, such as a user, product or company, is tagged in the media content and may thus become a media content participant or associated entity. Thus, such entity or the tagged entity's authorized representative may be able to modify specific control information regarding the entity. For example, a video participant may change associated privacy control information such that a media component comprising an image of the video participant is set as non-public. Further data structures may be included in the privacy array for such further purposes. Public keys of video participants may be included in the distributed ledger (smart contract) code so that they can emit specific transactions for removing their corresponding images.
Comprised in the device 900 is a processor 902, 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. The processor 902 may comprise more than one processor. The processor may comprise at least one application-specific integrated circuit, ASIC. The processor may comprise at least one field-programmable gate array, FPGA. The processor may be means for performing method steps in the device. The processor may be configured, at least in part by computer instructions, to perform actions.
The device 900 may comprise memory 904. The memory may comprise random-access memory and/or permanent memory. The memory may comprise at least one RAM chip. The memory may comprise solid-state, magnetic, optical and/or holographic memory, for example. The memory may be at least in part accessible to the processor 902. The memory may be at least in part comprised in the processor 902. The memory 904 may be means for storing information. The memory may comprise computer instructions that the processor is configured to execute. When computer instructions configured to cause the processor to perform certain actions are stored in the memory, and the device in overall is configured to run under the direction of the processor using computer instructions from the memory, the processor and/or its at least one processing core may be considered to be configured to perform said certain actions. The memory may be at least in part comprised in the processor. The memory may be at least in part external to the device 900 but accessible to the device. For example, control parameters affecting operations related to the generation and/or application of media vector and associated privacy control information may be stored in one or more portions of the memory and used to control operation of the apparatus. Further, the memory may comprise device-specific cryptographic information, such as secret and public key of the device 900.
The device 900 may comprise a transmitter 906. The device may comprise a receiver 908. The transmitter and the receiver may be configured to transmit and receive, respectively, information in accordance with at least one wired or wireless, cellular or non-cellular standard. The transmitter may comprise more than one transmitter. The receiver may comprise more than one receiver. The transmitter and/or receiver may be configured to operate in accordance with global system for mobile communication, GSM, wideband code division multiple access, WCDMA, long term evolution, LTE, IS-95, wireless local area network, WLAN, Ethernet and/or worldwide interoperability for microwave access, WiMAX, standards, for example. The device 900 may comprise a near-field communication, NFC, transceiver 910. The NFC transceiver may support at least one NFC technology, such as NFC, Bluetooth, Wibree or similar technologies.
The device 900 may comprise user interface, UI, 912. The UI may comprise at least one of a display, a keyboard, a touchscreen, a vibrator arranged to signal to a user by causing the device to vibrate, a speaker and a microphone. A user may be able to operate the device via the UI, for example to accept incoming telephone calls, to originate telephone calls or video calls, to browse the Internet, to manage digital files stored in the memory 904 or on a cloud accessible via the transmitter 906 and the receiver 908, or via the NFC transceiver 910, and/or to play games.
The device 900 may comprise or be arranged to accept a user identity module or other type of memory module 914. The user identity module may comprise, for example, a subscriber identity module, SIM, and/or a personal identification IC card installable in the device 900. The user identity module 914 may comprise information identifying a subscription of a user of device 900. The user identity module 914 may comprise cryptographic information usable to verify the identity of a user of device 900 and/or to facilitate encryption and decryption of communication effected via the device 900, such as the private and/or public keys as illustrated above.
The processor 902 may be furnished with a transmitter arranged to output information from the processor, via electrical leads internal to the device 900, to other devices comprised in the device. Such a transmitter may comprise a serial bus transmitter arranged to, for example, output information via at least one electrical lead to memory 904 for storage therein. Alternatively to a serial bus, the transmitter may comprise a parallel bus transmitter. Likewise the processor may comprise a receiver arranged to receive information in the processor, via electrical leads internal to the device 900, from other devices comprised in the device 900. Such a receiver may comprise a serial bus receiver arranged to, for example, receive information via at least one electrical lead from the receiver 908 for processing in the processor. Alternatively to a serial bus, the receiver may comprise a parallel bus receiver.
The device 900 may comprise further devices not illustrated in
The processor 902, the memory 904, the transmitter 906, the receiver 908, the NFC transceiver 910, the UI 912 and/or the user identity module 914 may be interconnected by electrical leads internal to the device 900 in a multitude of different ways. For example, each of the aforementioned devices may be separately connected to a master bus internal to the device, to allow for the devices to exchange information. However, as the skilled person will appreciate, this is only one example and depending on the embodiment various ways of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the present invention.
It is to be understood that the embodiments of the invention 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.
References 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 of the present invention. 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. The skilled person will appreciate that above-illustrated embodiments may be combined in various ways. Embodiments illustrated in connection with
Various embodiments and examples of the present invention 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 of the present invention.
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 invention. One skilled in the relevant art will recognize, however, that the invention 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 invention.
While the forgoing examples are illustrative of the principles of the present invention 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 invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.
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.
At least some embodiments of the present invention find industrial application in communications.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17196844.9 | Oct 2017 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FI2018/050726 | 10/10/2018 | WO | 00 |
