WO2020052752A1

WO2020052752A1 - Location-hiding based on variation of transmission

Info

Publication number: WO2020052752A1
Application number: PCT/EP2018/074665
Authority: WO
Inventors: Berthold PANZNER; Wolfgang Zirwas; Rakash SivaSiva GANESAN
Original assignee: Nokia Technologies Oy
Priority date: 2018-09-12
Filing date: 2018-09-12
Publication date: 2020-03-19

Abstract

An apparatus, method and computer program product is disclosed. The apparatus may comprise means for wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers. The transmitting means may be configured to send the first payload data to the different remote receivers at one or more of different times, with different power levels or with other artificial signal modifications. For example, the transmitting means may be configured to transmit the first payload data at different times responsive to determining that three or more remote receivers are within receiving range of the apparatus.

Description

LOCATION-HIDING BASED ON VARIATION OF TRANSMISSION

Field

Example embodiments relate to an apparatus and method for data transmission, for example by wireless radio devices such as internet-of things devices.

Background

The internet-of-things (loT) refers to a network of physical everyday devices, such as home appliances, vehicles and other items having data connectivity for enabling these devices to connect and exchange data, with a view to increasing functionality and efficiencies, for example in terms of automation of certain tasks and/or intelligent control of metered utilities. The rise of so-called smart home devices is one example of an loT system, for example linking digital assistants with smartphones, home heating systems, lighting systems etc. This may enable voice and/or remote control of such systems, metering their usage and possibly applying control algorithms to increase energy or data efficiency. Other examples may include the mounting of loT modules to bikes and cars, which may be for temporary rental purposes, to utility meters, point-of-sale (PoS) terminals, enterprise systems, logistics systems and so on. Wearables are another possible use of loT devices.

It is known to be able to locate the whereabouts of internet-of-things devices using received signals.

Summary

According to an example embodiment, there may be provided an apparatus, comprising: means for wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers; wherein the transmitting means is configured to send the first payload data to the different remote receivers at one or more of different times and/or with different power levels.

The transmitting means may be configured to send the first payload data to the different remote receivers at different times.

The apparatus may further comprise means for determining the number of remote receivers for receiving the first payload data by receiving a signal from each of said remote receivers that are in receiving range of the apparatus. The transmitting means may be configured to transmit the first payload data at different times responsive to determining that three or more remote receivers are within receiving range of the apparatus. The apparatus may further comprise means for controlling the transmitting means to send the first payload data to the different remote receivers at different times responsive to a user selection to hide or obfuscate the location of the apparatus.

The apparatus may further comprise means for presenting a user interface on a display of the apparatus enabling user control of the control means to hide or obfuscate the location of the apparatus.

The transmitting means may be configured to transmit the first payload data to the different remote receivers by means of respective directional beams, to transmit the first payload data to a first remote receiver by means of a first beam at a first time, and to one or more other remote receivers by means of respective other beams at respective other time offsets from the first time.

The transmitting means may be configured to transmit the first payload data only a single one of the remote receivers at a time by means of a respective directional beam.

The different transmit times may be determined randomly. The different transmit times may be predetermined. The apparatus may further comprising means for modifying the transmit power levels for sending the first payload data to the different remote receivers such that each is different.

The modifying means may modify the transmit power levels using beamforming of two or more beams in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

The apparatus may comprise a plurality of directional antennas, and wherein the modifying means may modify the transmit power levels by switching which of the antennas is or are used to transmit the first payload data to each different remote receiver in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap. The apparatus may comprise an antenna array for collectively providing the respective beams, and the apparatus may further comprise precoding means for modifying the weights applied to each element of the antenna array for each beam in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

The transmitting means may provide different artificial noise floor levels for the signals transmitted to the first to third base stations. The apparatus may comprise an internet-of-things apparatus providing the data source.

The apparatus may comprise a mobile internet-of-things apparatus, for example a wearable internet-of-things apparatus. According to another example embodiment, there may be provided a method, comprising: wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers at one or more of different times and/or with different power levels. The first payload data may be transmitted at different times.

The method may further comprise determining the number of remote receivers for receiving the first payload data by receiving a signal from each of said remote receivers that are in receiving range of an apparatus.

The first payload data may be transmitted at different times responsive to determining that three or more remote receivers are within receiving range of an apparatus.

The method may further comprise sending the first payload data to the different remote receivers at different times responsive to a user selection to hide or obfuscate the location of an apparatus.

The method may further comprise presenting a user interface on a display of the apparatus enabling user control to hide or obfuscate the location of the apparatus.

The method may comprise transmitting the first payload data to the different remote receivers by means of respective directional beams, to transmit the first payload data to a first remote receiver by means of a first beam at a first time, and to one or more other remote receivers by means of respective other beams at respective other time offsets from the first time. The method may comprise transmitting the first payload data only a single one of the remote receivers at a time by means of a respective directional beam.

The different transmit times may be determined randomly. The different transmit times may be predetermined.

The method may further comprise modifying the transmit power levels for sending the first payload data to the different remote receivers such that each is different.

Modifying the transmit power levels may comprise using beamforming of two or more beams in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

The modifying may comprise modifying the transmit power levels of an apparatus having a plurality of antennas by switching which of the antennas is or are used to transmit the first payload data to each different remote receiver in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

The method may be performed at an apparatus comprising an antenna array for collectively providing the respective beams, the method further comprising precoding for modifying the weights applied to each element of the antenna array for each beam in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap. The transmitting may use different artificial noise floor levels for the signals transmitted to the first to third base stations.

The method may be performed at an internet-of-things apparatus providing the data source.

The method may be performed at a mobile internet-of-things apparatus. The method may be performed at a wearable internet-of-things apparatus.

According to an example embodiment, there may be provided an apparatus comprising at least one processor, at least one memory directly connected to the at least one processor, the at least one memory including computer program code, and the at least one processor, with the at least one memory and the computer program code being arranged to perform the method of any preceding method definition. According to an example embodiment, there may be provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any preceding method definition. According to an example embodiment, there may be provided an apparatus, comprising: means for wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers; wherein the transmitting means is configured to send the first payload data to the different remote receivers with respective artificially modified signals.

According to an example embodiment, there may be provided a method, comprising: wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers; wherein the transmitting comprises sending the first payload data to the different remote receivers with respective artificially modified signals.

According to an example embodiment, there may be provided a non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising: wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers at one or more of different times, with different power levels or with other artificial signal modifications.

According to an example embodiment, there may be provided an apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus to wirelessly transmit a signal representing first payload data from a data source to a plurality of remote receivers at one or more of different times, with different power levels or with other artificial signal modifications. Description of Drawings

Example embodiments will now be explained, by way of non-limiting example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of an internet-of-things network comprising a geolocation server;

FIG. 2 is a flow diagram of operations in accordance with an example embodiment;

FIG. 3 is a graphical user interface that may be presented to an internet-of-things device during operation in accordance with an example embodiment;

FIG. 4 is a signal timing diagram showing how a first payload may be transmitted over an uplink to different receivers at different respective times, in accordance with an example embodiment;

FIG. 5 is a schematic plan-view showing a result of triangulation based on the payload signals received at different respective times, in accordance with the FIG. 4 signal timing diagram;

FIGS. 6A - 6D are graphical representations of how location obfuscation may be achieved in the case where receivers attempt to resolve multi-path components to a location, in accordance with an example embodiment;

FIG. 7 is a flow diagram of operations in accordance with another example embodiment; FIG. 8 is a schematic view of an apparatus for performing operations in accordance with example embodiments; and

FIGS. 9A and 9B are schematic views of non-transitory media for storing computer- readable code which, when executed by a processing apparatus, may perform operations in accordance with example embodiments.

Detailed Description

Example embodiments relate to wireless radio devices such as internet-of-things (loT) devices, but may not be limited to such devices. loT devices tend to be classified as low- power devices.

As used herein, an loT device is a physical device having data connectivity for communicating data associated with a particular application or set of applications to other loT devices and/or associated user computer terminals which may for example run monitoring and/or control applications. Typically, an loT device will relate to a domestic or industrial application, such as automated meter reading, controlling of an electrical or computer system, providing a digital assistant, possibly with voice control, tracking, logistics and other similar tasks.

Some loT devices may be mobile; that is they may change location over time. For example, some loT devices may be wearable, for example as a watch or other garment. For example, a watch or garment loT device may comprise a sensor which measures and gathers data relating to physical activity and/or other human parameters associated with exertion, for example during an exercise routine. This data may be fed-back to a dedicated server or application, which may be in the cloud, which may provide analytics and/or adapt a training programme. loT devices may communicate via an internet protocol (IP) network such as the Internet, using for example WiFi. loT devices may communicate also, or alternatively, via other wireless protocols such as Bluetooth. loT devices may also communicate via radio networks which may be cellular networks, such as by using GSM or UMTS and may take advantage of current and future generation technologies such as 3G, 4G, 5G and future standards.

Where loT devices are configured to communicate over cellular networks, they may comprise a network identity card, such as a subscriber identity module (SIM) card, or

USIM. A SIM card is an integrated circuit for securely storing an identifier and related key for identifying the particular device to the network and other devices. SIM cards may come in a number of form factors or sizes, any of which may be applicable. SIM cards are widely used and known in mobile handsets and other portable computing devices. A SIM card in this context is any subscriber identity system or module which can be removable or non-removable for identifying the device to a management system. Given their prevalence, a detailed description of SIM cards and their functionality is not required. The term loT card will be used throughout to refer generically to an identity card of the SIM card type or similar. An loT card effectively acts like a SIM card but for loT devices.

Other examples of what may be referred to as a SIM card or an loT card include one or more of chip SIMs, embedded SIMs (e.g. MFF2 UICC, eUICC, eSIM), and soft SIMs. Further information may be obtained at https://1ot.mobi/bloq/differences-between-sim- types-which-sim-to-choose. Where an loT device communicates via a network comprising a plurality of remote receivers, e.g. mobile network base stations, such as eNodeBs, gNodeBs, LoRa gateways or equivalents or any combination thereof, there is the possibility to at least estimate the geographic location of the loT device. This may be performed using passive geolocation using algorithms and data derived from reception of a legitimate message (payload) transmitted by the loT device, the payload itself not being specifically connected with the device’s location. The payload may for example simply represent energy usage data, or data derived from one or more wearable sensors. Example algorithms for passive geolocation include algorithms based on Time Difference of Arrival (TDoA), Angle of Arrival (AoA), signal strength evaluation, triangulation, resolving multi-path components, and so on. The user of the loT device may not be aware that their location can be determined.

In some situations, a user may not wish to be geographically located, or may at least desire the option of hiding their location.

Embodiments provide an apparatus and method enabling obfuscation of geographic location of an loT device, even by passive estimation methods.

FIG. 1 illustrates a scenario in which an loT device 10 spatially moves along a trajectory 12. The loT device 10 may be within communication range of at least first to third base stations 14 - 16 which are configured at least to receive payload data from the loT device 10. The loT device 10 may be any type of loT device and may generate payload data representing any form of sensed and/or measured data, but not necessarily data specifically related to its location, e.g. GPS co-ordinates. For example, if the loT device 10 is a fitness watch, it may comprise one or more sensors for sensing heart rate and blood pressure etc.

The loT device 10 may transmit its payload data to a remote server, referred to herein as an application server 17, which may be associated with one or more specific applications relating to the loT device 10. For example, the application server 17 may be health analytics server for receiving sensed data from loT devices of multiple users, including the loT device 10, and may be configured to provide analytics relating to historical and current physical activity, generating graphical charts relating to progress towards certain goals and so on. The application server 17 is the intended destination of the payload data from the loT device 10. The payload data may pass to the application server 17 via an loT core 18 which provides a service for managing and connecting large numbers of loT devices and may include identification, authentication and updating services for said loT devices.

A further server, namely a geolocation server 19, may in practise have access to payload data sent via the loT core 18 (or through some other node in communication with the base stations 14 - 16) and through known means may be able to estimate the geolocation of the loT device 10. As will be appreciated, if the geographic locations of the respective base stations 14 - 16 are fixed and known, the geolocation server may apply a correlation between different copies of the uplink payload data received by said base stations, and use TDoA and triangulation using a timestamp at the receive time to estimate the geolocation of the originating loT device 10.

In accordance with an example embodiment, the loT device 10 is configured to perform the operations indicated in FIG. 2. The FIG. 2 operations may be implemented in software, hardware, firmware or a combination thereof.

A first operation 21 may comprise determining a number of remote receivers for receiving first payload data. A second operation 22 may comprise wirelessly transmitting a signal representing the first payload data from a data source to the plurality of remote receivers at different respective times and/or with different power levels. The first payload data refers to identical or near- identical copies of the same data. In some embodiments, in the second operation 22, other artificial signal modifications may be applied in addition to (or alternatively to) the shown case.

In this way, a form of pre-coding is performed at the loT device 10 on the first payload data so that each base station 14 - 16 will receive the same first payload data, but because of the modifications in terms of one or more of different times, different power levels or other artificial signal modifications, the actual geolocation of the first device will be obfuscated when resolved at the geolocation server 19. For example, if different times are used for transmitting the same first payload data, because of the delay in each base station 14 - 16 receiving said payload data (due to the different sending times), the geolocation may not be determined.

Determining the number of remote receivers, or base stations 14 - 16, may be performed by receiving data requests from the different base stations, which may be automatic, or in response to issuing an acknowledge request signal to each base station that happens to be in range. Either way, a matrix of the in-range base stations 14 - 16 may be determined as may be their respective directions from the loT device 10. In some embodiments, the pre-coding operations of FIG. 2 may only be performed when a predetermined number of base stations 14 - 16 are identified as within range. For example, because at least three base stations 14 - 16 are needed for TDoA triangulation, the presence of three or more base stations 14 - 16 in the matrix may be a trigger for the pre-coding.

In some embodiments, the loT device 10 may present via an output, such as via a graphical user interface (GUI) of the device, an option enabling user-selection of an obfuscation mode to maintain location secrecy. FIG. 3 shows an example screenshot of such a prompt. In response to a positive selection, the pre-coding may be performed.

The prompt may for example be presented responsive to a predetermined event, such as if three or more base stations 14 - 16 are identified, or based on the type of application the loT device 10 is being used for. For example, if the loT device 10 is being used for mobile data acquisition, e.g. as a smartphone, the fact that it changes location on a regular basis may be a factor in indicating that the user should at least have the option of obfuscating passive geolocation performed remotely.

In some embodiments, based on the determined base station matrix, the loT device 10 may employ beamforming to select a first base station 14 to transmit the first payload data to, and nullifies other beams to the other base stations 15, 16 so that, at a first time, only the first base station 14 may receive the first payload data. Subsequently, with a randomised or predetermined time delay, the loT device 10 may cause another beam to transmit the first payload data to the second base station 15, and nullifies other beams to the other base stations 14, 16. Subsequently, with another randomised or predetermined time delay, the loT device 10 may cause another beam to transmit the first payload data to the third base station 16, and nullifies other beams to the other base stations 14, 15. Nullifying may involve zero-forcing the other beams using zero beamforming weights.

FIG. 4 graphically illustrates the principle of the pre-coding operation. The first payload data (“UL packet”), rather than being simultaneously transmitted to all three base stations 14 - 16, is transmitted to each base station using a respective time delay (T1 , T2, T3) which may be offsets from a reference time tq, or one of said times, e.g. T1 may be the reference time from which the other delays, e.g. T2 and T3 are determined. In consequence, the base stations 14 - 16 receive the first payload at times determined not only by propagation distance, but also by the pre-coded delays or offsets T1 , T2, T3, which will be reflected in the timestamp forwarded by each base station to the geolocation server 19.

FIG. 5 graphically illustrates how obfuscation results from this process at the geolocation server 19. Reference numeral 30 indicates the real location of the loT device 10, which happens to be equidistant from the first to third base stations 14 - 16. Hence, the uplink payload data will have the same travel time over the air to each of the first to third base stations 14 - 16, assuming pure line-of-sight. However, due to pre-coding, the same uplink payload data arrives at the first to third base stations 14 - 16 at different times (t1 < T2 < T3) and hence the triangulation process will result in an intersection point 32 which is a wrong location, some distance from the real location of the loT device 10.

In some instances, there may be too few or no intersections due to the above method, and hence triangulation is not possible and the location of the loT device 10 cannot be estimated at all.

In some embodiments, other pre-coding methods may be employed in addition to, or alternatively to, the above method. For example, a different pre-coding method may be used to avoid passive geolocation techniques based on Received Signal Strength Indication (RSSI). In this case, the loT device 10 is configured to enforce transmit beamforming to mimic different receive power levels at the different first to third base stations 14 - 16 independent from the loT device’s real location.

For example, similar to the previous pre-coding method for RSSI passive geolocation, instead of modifying the beamforming, where there is an array of multiple (directive) antenna elements at the loT device 10, switching between the different antenna elements can be used to mimic different receive power levels.

As a specific embodiment, one can also consider a precoder, which combines the variation of the times (T1 < T2 < T3) for the data replica together with a variation of the according transmit-powers. In this way, even more improved obfuscation becomes possible.

In another embodiment, one might add, before transmission, different artificial noise floor levels for the signals to the first to third base stations 14 - 16. By proper artificial noise floor levels, only the first base station 14 may be able to decode the uplink data, thereby also making triangulation impossible. This is an example of artificial signal modification before transmission. For example, where the passive localisation method employed by the geolocation server 19 is based on resolving multi-path components (MPC), i.e. resolving scattering clusters, the loT device 10 may be configured to vary the MPCs of the channel impulse response (CIR) that will be received at the first to third base stations 14 - 16. The time-variant CIR of the wireless channel comprises taps t_{h, (W}ith n being the number of taps or MPCs) or the MPCs that represent the scattering clusters between the antenna at the loT device transmitter to the antenna at receiver of the first to third base stations 14 - 16. Pre-coding by adapting the complex weights of each antenna elements at the loT device array can actively change the apparent position and strength of the taps at the first to third base station 14 - 16 by exciting new MPCs and thus mimicking a different location.

FIGS. 6A - 6D illustrates a simulation of this method, whereby in FIG. 6A we assume a first base station at a location (0, 0, 25) m and an loT device at a location (400, 0, 1 ) m in a dense urban environment at 868 MHz. FIG. 6B shows the CIR with twenty taps or MPCs. The MPCs that can be resolved in the sampled CIR at the first base station correspond to twenty scattering clusters in this scenario. Fingerprinting or any other method may allocate real scattering cluster positions to the taps, i.e. so that each tap in the CIR corresponds to a scattering cluster located at (x, y.) The method outlined in this case is to modify the taps of the channels so that the derived information on the location of the scattering clusters cannot be used to infer the real position of the loT device. FIG. 6D shows the result of arbitrary beamforming applied by the loT device antenna array whereby the observed MPCs in the CIR change, indicated by the difference in black and white dots.

In accordance with another example embodiment, the loT device 10 is configured to perform the operations indicated in FIG. 7. The FIG. 7 operations may be implemented in software, hardware, firmware or a combination thereof.

In a first operation 71 , it is determined if a channel (or base station) matrix can be determined. If so, the process moves to another operation 72. If not, an operation 73 of enforcing a downlink message from base stations is performed to obtain the channel matrix. This may be an acknowledge request. The process feeds back to the first operation 71. ln another operation 72, it is determined if there is sufficient spatial degree of freedom for beamforming to provide the initial method described above with reference to FIGS. 2, 4 and 5 by means of nullifying beams to particular base stations to prevent correct triangulation. If not, for example if there is overlap of a beam with two or more base stations, an alternative pre-coding method may be employed in an operation 74, for example one or more of the alternatives outlined above. The process then moves to a further operation 77 whereby passive geolocation algorithms will result in a wrong location or no location.

If the result from operation 72 is that there is sufficient degree-of-freedom, another operation 75 may comprise calculating the number of beams to force or pre-code to zero. This may comprise all except one beam, or possibly all except two beams which may still prevent triangulation. This operation 75 may also or alternatively comprise determining the order of beams and the time delay or time offsets.

Another operation 76 may comprise sending the payload data in multiple uplink beams, as computed in the previous operation 75, using the respective time delays or time offsets. The process then moves to operation 77 as mentioned above.

FIG. 8 is a schematic view of an apparatus 160 which may provide the loT device 10 shown in FIG. 1.

The apparatus 160 may have a processor 162, a memory 164 closely-coupled to the processor and comprised of a RAM 166 and ROM 168. The apparatus 160 may comprise a network interface 170, and optionally a display 172 and one or more hardware keys 174. The apparatus 160 may comprise one or more such network interfaces 170 for connection to a network, e.g. a radio access network. The one or more network interfaces 170 may also be for connection to the internet, e.g. using WiFi or similar. The processor 162 is connected to each of the other components in order to control operation thereof.

The memory 164 may comprise a non-volatile memory, a hard disk drive (HDD) or a solid state drive (SSD). The ROM 168 of the memory stores, amongst other things, an operating system 176 and may store one or more software applications 178. The RAM 166 of the memory 164 may be used by the processor 162 for the temporary storage of data. The operating system 166 may contain code which, when executed by the processor, implements the operations as described above and also below, for example in the various flow diagrams. As mentioned below, the memory 164 may comprise any suitable form, and may even be implemented in the cloud.

The processor 162 may take any suitable form. For instance, the processor 162 may be a microcontroller, plural microcontrollers, a processor, or plural processors and the processor may comprise processor circuitry.

FIGS. 9A and 9B show tangible non-volatile media, respectively a removable memory unit 182 and a compact disc (CD) 184, storing computer-readable code which when run by a computer may perform methods according to embodiments described above and below. The removable memory unit 182 may be a memory stick, e.g. a USB memory stick, having internal memory 186 storing the computer-readable code. The memory 186 may be accessed by a computer system via a connector 185. The CD 184 may be a CD-ROM or a DVD or similar. Other forms of tangible storage media may be used.

Implementations of any of the above described blocks, apparatuses, systems, techniques or methods include, as non-limiting examples, implementations as hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. Some embodiments may be

implemented in the cloud and utilize virtualized modules.

Embodiments of the present invention may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware may reside on memory, or any computer media. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a“memory” or“computer-readable medium” may be any non-transitory media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

Reference to, where relevant,“computer-readable storage medium”,“computer program product”,“tangibly embodied computer program” etc., or a“processor” or“processing circuitry” etc. should be understood to encompass not only computers having differing architectures such as single/multi-processor architectures and sequencers/parallel architectures, but also specialised circuits such as field programmable gate arrays FPGA, application specify circuits ASIC, signal processing devices and other devices. References to computer program, instructions, code etc. should be understood to express software for a programmable processor firmware such as the programmable content of a hardware device as instructions for a processor or configured or configuration settings for a fixed function device, gate array, programmable logic device, etc.

As used in this application, the term“circuitry” refers to all of the following: (a) hardware- only circuit implementations (such as implementations in only analogue and/or digital circuitry) and (b) to combinations of circuits and software (and/or firmware), such as (as applicable): (i) to a combination of processor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a server, to perform various functions) and (c) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. In this brief description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term‘example’ or‘for example’ or‘may’ in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some of or all other examples. Thus‘example’, ‘for example’ or‘may’ refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a sub-class of the class that includes some but not all of the instances in the class. It is therefore implicitly disclosed that a features described with reference to one example but not with reference to another example, can where possible be used in that other example but does not necessarily have to be used in that other example.

Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that

modifications to the examples given can be made without departing from the scope of the invention as claimed.

Features described in the preceding description may be used in combinations other than the combinations explicitly described.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not. Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. Apparatus, comprising:

means for wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers;

wherein the transmitting means is configured to send the first payload data to the different remote receivers at one or more of different times and/or with different power levels.

2. The apparatus of claim 1 , wherein the transmitting means is configured to send the first payload data to the different remote receivers at different times.

3. The apparatus of claim 1 or claim 2, further comprising means for determining the number of remote receivers for receiving the first payload data by receiving a signal from each of said remote receivers that are in receiving range of the apparatus.

4. The apparatus of any preceding claim, wherein the transmitting means is configured to transmit the first payload data at different times responsive to determining that three or more remote receivers are within receiving range of the apparatus.

5. The apparatus of any preceding claim, further comprising means for controlling the transmitting means to send the first payload data to the different remote receivers at different times responsive to a user selection to hide or obfuscate the location of the apparatus.

6. The apparatus of claim 5, further comprising means for presenting a user interface on a display of the apparatus enabling user control of the control means to hide or obfuscate the location of the apparatus.

7. The apparatus of any preceding claim, wherein the transmitting means is configured to transmit the first payload data to the different remote receivers by means of respective directional beams, to transmit the first payload data to a first remote receiver by means of a first beam at a first time, and to one or more other remote receivers by means of respective other beams at respective other time offsets from the first time.

8. The apparatus of claim 7, wherein the transmitting means is configured to transmit the first payload data only a single one of the remote receivers at a time by means of a respective directional beam.

9. The apparatus of any preceding claim, wherein the different transmit times are determined randomly.

10. The apparatus of any of claims 1 to 8, wherein the different transmit times are predetermined.

1 1. The apparatus of any preceding claim, further comprising means for modifying the transmit power levels for sending the first payload data to the different remote receivers such that each is different.

12. The apparatus of claim 1 1 , when dependent on claim 7 or claim 8, wherein the modifying means modifies the transmit power levels using beamforming of two or more beams in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

13. The apparatus of claim 1 1 , when dependent on claim 7 or claim 8, wherein the apparatus comprises a plurality of directional antennas, and wherein the modifying means modifies the transmit power levels by switching which of the antennas is or are used to transmit the first payload data to each different remote receiver in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

14. The apparatus of claim 7 or claim 8, or any claim dependent thereon, wherein the apparatus comprises an antenna array for collectively providing the respective beams, the apparatus further comprising precoding means for modifying the weights applied to each element of the antenna array for each beam in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

15. The apparatus of any preceding claim, wherein the transmitting means provides different artificial noise floor levels for the signals transmitted to the first to third base stations.

16. The apparatus of any preceding claim, comprising an internet-of-things apparatus providing the data source.

17. The apparatus of claim 16, comprising a mobile internet-of-things apparatus.

18. The apparatus of claim 17, comprising a wearable internet-of-things apparatus.

19. A method, comprising:

wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers at one or more of different times and/or with different power levels.

20. The method of claim 19, wherein the first payload data is transmitted at different times.

21. The method of claim 20, further comprising determining the number of remote receivers for receiving the first payload data by receiving a signal from each of said remote receivers that are in receiving range of an apparatus.

22. The method of claim 20 or claim 21 , wherein the first payload data is transmitted at different times responsive to determining that three or more remote receivers are within receiving range of an apparatus.

23. The method of any of claims 20 to 22, further comprising sending the first payload data to the different remote receivers at different times responsive to a user selection to hide or obfuscate the location of an apparatus.

24. The method of claim 23, further comprising presenting a user interface on a display of the apparatus enabling user control to hide or obfuscate the location of the apparatus.

25. The method of any of claims 19 to 24, comprising transmitting the first payload data to the different remote receivers by means of respective directional beams, to transmit the first payload data to a first remote receiver by means of a first beam at a first time, and to one or more other remote receivers by means of respective other beams at respective other time offsets from the first time.

26. The method of claim 25, comprising transmitting the first payload data only a single one of the remote receivers at a time by means of a respective directional beam.

27. The method of any of claims 19 to 26, wherein the different transmit times are determined randomly.

28. The method of any of claims 19 to 26, wherein the different transmit times are predetermined.

29. The method of any of claims 19 to 28, further comprising modifying the transmit power levels for sending the first payload data to the different remote receivers such that each is different.

30. The method of claim 29, when dependent on claim 25 or claim 26, wherein modifying the transmit power levels comprises using beamforming of two or more beams in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

31. The method of claim 29, when dependent on claim 25 or claim 26, wherein the modifying comprises modifying the transmit power levels of an apparatus having a plurality of antennas by switching which of the antennas is or are used to transmit the first payload data to each different remote receiver in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

32. The method of claim 25 or claim 26, or any claim dependent thereon, performed at an apparatus comprising an antenna array for collectively providing the respective beams, the method further comprising precoding for modifying the weights applied to each element of the antenna array for each beam in the event that there is insufficient space to transmit the first payload data to the different remote receivers using respective beams without overlap.

33. The method of any of claims 19 to 32, wherein the transmitting uses different artificial noise floor levels for the signals transmitted to the first to third base stations.

34. The method of any preceding claim, performed at an internet-of-things apparatus providing the data source.

35. The method of claim 34, performed at a mobile internet-of-things apparatus.

36. The method of claim 35, performed at a wearable internet-of-things apparatus.

37. An apparatus comprising at least one processor, at least one memory directly connected to the at least one processor, the at least one memory including computer program code, and the at least one processor, with the at least one memory and the computer program code being arranged to perform the method of any of claims 19 to 36.

38. A computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any of claims 19 to 36.

39. Apparatus, comprising:

wherein the transmitting means is configured to send the first payload data to the different remote receivers with respective artificially modified signals.

40. The apparatus of claim 39, comprising an internet-of-things apparatus providing the data source.

41. The apparatus of claim 40, comprising a mobile internet-of-things apparatus.

42. The apparatus of claim 41 , comprising a wearable internet-of-things apparatus.

43. A method, comprising:

wirelessly transmitting a signal representing first payload data from a data source to a plurality of remote receivers;

wherein the transmitting comprises sending the first payload data to the different remote receivers with respective artificially modified signals.

44. The method of any preceding claim, performed at an internet-of-things apparatus providing the data source.

45. The method of claim 44, performed at a mobile internet-of-things apparatus.

46. The method of claim 45, performed at a wearable internet-of-things apparatus.

47. An apparatus comprising at least one processor, at least one memory directly connected to the at least one processor, the at least one memory including computer program code, and the at least one processor, with the at least one memory and the computer program code being arranged to perform the method of any of claims 43 to 46.

48. A computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any of claims 43 to 46.

49. A non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising:

50. An apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus:

to wirelessly transmit a signal representing first payload data from a data source to a plurality of remote receivers at one or more of different times and/or with different power levels.

51. A non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising:

52. An apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus:

to wirelessly transmit a signal representing first payload data from a data source to a plurality of remote receivers, wherein the transmitting comprises sending the first payload data to the different remote receivers with respective artificially modified signals.