Peer radar sensing

Abstract

A method, performed by a wireless electronic device, for radar sensing. The method comprises wirelessly transmitting (310) a radar discovery signal to a radar- capable device. The radar discovery signal is indicative of a request for radar sensing to be performed by the radar-capable device. The radar sensing is requested to be performed in a direction corresponding to an angle of arrival of the radar discovery signal as seen by the radar-capable device. The method further comprises wirelessly obtaining (350) radar sensing data from the requested radar sensing.

Description

[0001] PEER RADAR SENSING

[0002] TECHNICAL FIELD

[0003] The embodiments herein relate to a radar device and a method for radar sensing. A corresponding computer program and a computer program carrier are also disclosed.

[0004] BACKGROUND

[0005] Radar-based environment characterization, or radar sensing in other words, is a well-known technology with a wide range of use cases. Radar functionality may be cheaply integrated in 5G modems for e.g. smartphones, loT devices and other types of electronic devices, since hardware in these devices already supports Radio Frequency (RF) signal transmission and reception.

[0006] There is a trend towards higher carrier frequencies in wireless communications. In 5G, mm-waves are used for cellular communication between base-stations and user devices. The higher frequencies provide more spectrum for increased capacity and also wider bandwidth channels for increased user data rates. In 6G, even higher carrier frequencies are foreseen, in the so-called sub-THz band above 100 GHz.

[0007] The wider bandwidth of a radar signal, the better sensing performance can be achieved. Hence, the evolution of wireless communication standards towards using wide bandwidth spectrum allocations increases the radar sensing capabilities, e.g. in 5G devices and beyond.

[0008] Some radar systems consist of multiple cooperating devices. Such radar systems, which may also be referred to as distributed radar systems, consists of multiple radar sensors collaborating to improve detection, e.g. as in prior art document Lee et al, A peer- to-peer collaboration framework for multi-sensor data fusion, in Journal of Network and Computer Applications 35 (2012), pp 1052-1066 or in prior art document W02016011407A1. Common for such prior art distributed radar systems is that the radar system is fairly well defined by multiple known and interconnected sensors that are controlled by a control function to improve the sensing of certain more or less distant objects, areas, or volumes. These prior arts may for example optimize the functionality according to various criteria which dynamically selects which radar sensors that participate in the sensing depending on certain cost models related to the target area of sensing. Extended Reality (XR), which is a joint term for Augmented Reality (AR) and Virtual Reality (VR), is an emerging technology where a user wears a headset, and the headset typically contains several different types of sensors to sense and map up the environment (cameras, radars, etc.) and the user's gestures (cameras, IMU, etc.). However, due to the physical limitations of the headset and its position on the head of the user, there are practical limitations of how the sensors embedded in the headset can track the user's movements and position.

[0009] When a device, such as a wireless device, is performing a monostatic radar sensing operation the environment around the device may be characterized by means of analysing the received signal based on surrounding objects reflecting the transmitted signal. However, it is more challenging to get a good characterization of the view of the device itself or a user or object very close to the device or user. E.g. it may be challenging to perform pose or gesture analysis of a user of the device. Such sensing to characterize the device itself or objects very close to the device itself is typically better performed by one or more other devices at different locations but in proximity. There are solutions available for e.g. multistatic radar systems where devices are collaborating to perform radar sensing which may be utilized for such purposes. Such systems are however complex and may e.g. require high accuracy time / frequency synchronization in-between collaborating devices.

[0010] Traditional distributed sensor systems may be one solution to track the user by all surrounding devices, but such solutions have typically relied on that those surrounding sensors are connected and there is some control function that can coordinate their sensing and its processing. For a user moving around, partly in areas new to the user, the surrounding devices might not be available for the user to connect, and the sensing- capable devices may operate independently and not be coordinated by a coordinating control function. Furthermore, having all sensors collaborate to sense different areas and being able to share that with any user creates a substantial privacy concern, and may violate existing and future regulations.

[0011] SUMMARY

[0012] There is thus a need for a more efficient approach for implementing radar sensing in certain scenarios. An object of embodiments herein may be to obviate some of the problems related to radar sensing of objects close to a wireless electronic device.

[0013] According to a first aspect, the object is achieved by a method, performed by a wireless electronic device, for radar sensing.

[0014] The method comprises wirelessly transmitting a radar discovery signal to a radar- capable device. The radar discovery signal is indicative of a request for radar sensing to be performed by the radar-capable device. The radar sensing is requested to be performed in a direction corresponding to an angle of arrival of the radar discovery signal as seen by the radar-capable device.

[0015] The method further comprises wirelessly obtaining radar sensing data from the requested radar sensing.

[0016] According to a second aspect, the object is achieved by a wireless electronic device configured to perform the method according to the first aspect.

[0017] According to a third aspect, the object is achieved by a method performed by a radar-capable device, for radar sensing.

[0018] The method comprises wirelessly receiving a radar discovery signal transmitted from a wireless electronic device.

[0019] The method further comprises determining a direction of arrival of the received radar discovery signal.

[0020] The method further comprises performing radar sensing in a direction corresponding to the determined direction of arrival of the received radar discovery signal.

[0021] The method further comprises transmitting radar sensing data from the radar sensing such that the radar sensing data is obtainable by the wireless electronic device.

[0022] According to a fourth aspect, the object is achieved by a radar-capable device configured to perform the method according to the third aspect.

[0023] According to a further aspect, the object is achieved by a computer program comprising instructions, which when executed by a processor, causes the processor to perform actions according to any of the aspects above. According to a further aspect, the object is achieved by a carrier comprising the computer program of the aspect above, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

[0024] Since the radar sensing is requested to be performed in the direction corresponding to the angle of arrival of the radar discovery signal as seen by the radar-capable device, radar sensing of objects close to the wireless electronic device is enabled.

[0025] Embodiments disclosed herein further enables improved environmental understanding. Embodiments disclosed herein allows a user to have external sensing of his / her pose, gestures, and even position, even if the user device has no such capability due to its limitations depending on its placement, direction, etc. One example is a user that wears AR glasses with limited capability to sense the user's own movements. Such a user may now get the movements tracked from surrounding sensors in a simple and secure way. Other examples includes the analysis of objects in the user's local environment that may be relevant for the use case of the user.

[0026] Embodiments disclosed herein further allow the requesting device to initiate device centric radar sensing without the need to support the radar sensing implementation on its own.

[0027] BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In the figures, features that appear in some embodiments are indicated by dashed lines.

[0029] The various aspects of embodiments disclosed herein, including particular features and advantages thereof, will be readily understood from the following detailed description and the accompanying drawings, in which:

[0030] Figure 1 is a block diagram schematically illustrating a system for radar sensing,

[0031] Figure 2 is a block diagram schematically illustrating a further system for radar sensing,

[0032] Figure 3 is a flow chart illustrating a method according to some embodiments herein,

[0033] Figure 4 is a block diagram schematically illustrating an electronic device according to some embodiments herein,

[0034] Figure 5 is a block diagram schematically illustrating a radar-capable device. DETAILED DESCRIPTION

[0035] Embodiments herein relate to radar sensing.

[0036] In the below, an XR headset will be used as an example electronic device, but embodiments disclosed herein are not limited to such types of user devices or use cases.

[0037] Embodiments herein disclose a first electronic device, such as an XR headset, which is assisted by radar sensing from surrounding radar-capable devices, e.g. loT devices, smart speakers, other smart home or building appliances, connected wireless IT equipment such as monitors, etc., in a simple way, without having to have further access to those devices. The first electronic device may be a user device.

[0038] The first electronic device transmits a Radar Discovery (RD) signal to surrounding units, and radar-capable devices in the surrounding detects this RD signal, the direction of its origin, performs sensing in that direction, and shares sensing data related to the first electronic device with the first electronic device. The sharing of the sensing data may be performed securely. This may be done as a one-time sensing, or as continuous sensing with different types of schemes.

[0039] In some other embodiments, sensing may additionally be performed with a camera, lidar, ultra-sound, etc. In yet further embodiments, there are mechanisms applied to secure relative anonymity between peer radar devices and the user device, and there are security mechanisms in place preventing other user devices from accessing the sensing results.

[0040] In yet further embodiments, the radar-capable device transmits sensing data to a data server. The user electronic device or another device coupled to user electronic device may receive the captured sensor data from the data server.

[0041] For detecting a presence of an object and its overall location and movement characteristics, a multitude of well established, radar-based approaches exist. Conventional radar sensing may be used to identify a range (distance) to an object, a direction to the object, and size of the object based on characteristics of a signal reflected by the object, as well as its relative movement speed based on a Doppler shift of the received signal.

[0042] Conventional radar schemes may use a variety of signal designs of which some will be described shortly below. Continuous Wave (CW) radar

[0043] In CW radar, a continuous radio frequency RF signal is transmitted and continuously emitted by a radar antenna. It includes measuring the Doppler shift caused by moving objects. CW radar lacks range information and relies solely on Doppler frequency shift for velocity measurement.

[0044] Frequency Modulated Continuous Wave (FMCW)

[0045] FMCW radar transmits a continuous wave with a frequency that varies linearly over time. By comparing the transmitted and received signals FMCW radar measures the range to the target based on the frequency difference, and it also provides velocity information from the Doppler shift.

[0046] Orthogonal Frequency Division Multiplexing (OFDM) radar

[0047] Coded radar, often implemented using Orthogonal Frequency Division Multiplexing (OFDM), uses coded waveforms for transmission. An OFDM radar transmits a burst of data made up of multiple frequencies, like WiFi. The same OFDM signal can be used to transmit data like a communication system alongside radar functions.

[0048] Stepped Frequency Continuous Wave (SFCW) radar

[0049] SFCW radar is like FMCW radar but operates by transmitting a series of discrete frequencies instead of a continuously varying frequency. This discrete frequency hopping enables simplified signal generation compared to FMCW and immunity to certain types of interference.

[0050] Pulsed Radar

[0051] Pulsed radar consists of short bursts or pulses of electromagnetic energy that are transmitted from the radar antenna. These pulses are typically of high power and short duration. After transmitting a pulse, the radar system waits for a brief period, known as the "listening" or "dwell" time, during which it listens for the return echoes from targets. The round-trip time of these echoes provides information about the range to the target.

[0052] Each of these radar transceiver schemes has its own advantages and applications, depending on factors such as cost, power consumption, required range, resolution, velocity measurement accuracy, and susceptibility to interference.

[0053] A radar sensing system may operate in a monostatic fashion, where the same unit is both transmitting a radar signal as well as receiving reflected signals. Alternatively bi- static or multi-static scenarios may be used, where transmitting and receiving units are separated.

[0054] Object identification

[0055] For obtaining more detailed information about an object, including identifying an object type or activity, a micro-Doppler (in the following abbreviated as uDoppler) signature may distinguish between different object types and different characteristics within an object.

[0056] In one type of solutions, time-Doppler signatures may be detected, depicting variation in detailed Doppler frequency components over time. The overall object pattern is collected during an extended observation window and the pattern may contain periodic / cyclo-stationary elements.

[0057] The Doppler shift as a function of object part movement can be expressed as Fd= Ft-^ , and the subject velocity is estimated as v = .

[0058] Where:

[0059] Fd: doppler frequency

[0060] Ft: Carrier (transmitter) frequency

[0061] - v: doppler velocity

[0062] - c: speed of light

[0063] When a radar signal with non-negligible relative bandwidth (BW) is used, but the Doppler estimation is based on the centre frequency, the relative error is ~ ~ which creates smearing in the frequency domain. AFtmay be caused by signal BW, hardware imperfections, etc. The Doppler resolution improves for higher Ft. For example, Ft=30 GHz may allow arm separation while 10 GHz may lead to smearing that hides the arm details.

[0064] In more advanced radar receivers, e.g. when the Doppler estimation is based on frequency offset hypothesis testing, the signal BW need not have an impact on the frequency resolution.

[0065] The signal BW has no impact on time-resolution. In the limit, it bounds time resolution, but this is not an issue for uDoppler variations on the 0.1-10 Hz time scale.

[0066] In another type of solutions, a range-Doppler signature may be estimated. For a given time instant, each uDoppler contribution may be further separated in terms of range. A higher BW yields higher range resolution, which may be used e.g. for gait detail analysis, and to isolate different body parts and to identify whether a person carries a gun. Range resolution of 0.2 m suffices for foot, while a cm-level range resolution is needed for hand.

[0067] As mentioned above, for baseline Doppler estimation, the higher BW also proportionally reduces frequency resolution, as it increases max Doppler shift error due to larger max AF. This may be mitigated by aggregating over multiple narrow band (NB) channels, or by using an advanced receiver, e.g. hypothesis-based correlation detection.

[0068] The estimated uDoppler signatures may be used e.g. as input to machine learning (ML) models trained to distinguish different signature patterns and map them to different object types and their movement types, in order to complete the identification task.

[0069] Methods for analyzing captured data in two or more steps have been disclosed. For example, extracting one or more features or information elements in captured uDoppler data in a first step and based on classification of such first feature performing a second in- depth analysis of same or more of the captured data.

[0070] Embodiments disclosed herein will now be described in relation to Figure 1 -Figure 3. Figure 1 schematically illustrates a system for radar sensing. The system includes a wireless electronic device 101 and a radar-capable device such as a first radar- capable device 102 and a second radar-capable device 103. The system of Figure 1 further includes a data server 110. The data server 110 may store radar sensing data from the radar sensing. The data server 110 may be a cloud server, or a mobile network server or any other data server. In some embodiments disclosed herein the data server 110 may be a local device, for example one of a group of radar-capable devices, such as the second radar-capable device 103.

[0071] Figure 2 schematically illustrates a further system for radar sensing which may be used instead of or as a complement to the system of Figure 1. In Figure 2 the data server 110 is not part of the system for radar sensing.

[0072] Figure 3 illustrates a flowchart of a method for radar sensing, performed by a wireless electronic device 101 and a radar-capable device such as a first radar-capable device 102 and a second radar-capable device 103. The wireless electronic device 101 may for example be a wireless communications device, such as a User Equipment (UE), or electronic wearable devices, such as AR glasses or smart watches. In a scenario applicable to embodiments disclosed herein the wireless electronic device 101 is within communication range of one or more radar-capable devices, such as the first radar-capable device 102 and the second radar-capable device 103.

[0073] Action 310

[0074] The wireless electronic device 101 wirelessly transmits a radar discovery signal to the radar-capable device 102, 103. The radar-capable device 102, 103 may be a monostatic radar device or a bi-static radar device or a multi-static radar device. For example, the second radar-capable device 103 may transmit the radar signals and the first radar-capable device 102 may receive the radar signals.

[0075] The radar discovery signal is indicative of a request for radar sensing to be performed by the radar-capable device 102, 103. The radar sensing is requested to be performed in a direction corresponding to an angle of arrival of the radar discovery signal as seen by the radar-capable device 102, 103.

[0076] Transmitting the radar discovery signal to the radar-capable device 102, 103 may comprise transmitting information indicative of a configuration of radar measurements for the radar sensing. The configuration of radar measurements may comprise information on which characteristics of radar sensing or parameters suggested for the sensing signal or type of sensing is needed, to guide the radar-capable device 102, 103 since different radar-capable devices may have different capabilities. Examples of the configuration of radar measurements may be information that indicates a suggestion to the radar capable device 102, 103 how to perform the radar sensing. Such information may e.g. be:

[0077] - transmit power for the radar signal;

[0078] - Radar signal pulse length;

[0079] - Radar signal bandwidth;

[0080] - Radar signal frequency;

[0081] - Beam width;

[0082] - Expected object mobility; and

[0083] - Whether or not micro doppler sensing is requested.

[0084] In some embodiments disclosed herein transmitting the radar discovery signal to the radar-capable device 102, 103 comprises transmitting a request for repeated radar sensing during a time period. A repeated radar sensing during a time period may be advantageous for example for gesture recognition or other motion recognition. The wireless electronic device 101 may further transmit an encryption key with the radar discovery signal to the radar-capable device 102, 103. This may be done to support encrypted transmission of radar sensing data from the radar-capable device 102, 103 in action 350 below.

[0085] In some embodiments disclosed herein the wireless electronic device 101 provides a network address of the data server 110 with the radar discovery signal.

[0086] At the other end the radar-capable device 102, 103 wirelessly receives the radar discovery signal transmitted from a wireless electronic device 101. In some embodiments disclosed herein the radar-capable device 102, 103 receives the encryption key with the radar discovery signal and later in action 350 below transmits the radar sensing data encrypted with the encryption key.

[0087] Action 320

[0088] The radar-capable device 102, 103 determines a direction of arrival of the received radar discovery signal.

[0089] In some embodiments discloses herein determining the direction of arrival of the received radar discovery signal includes determining whether the direction of arrival of the received radar discovery signal is a line-of-sight direction. Then the following steps after the determination of the direction of arrival may be performed only if the direction of arrival of the received radar discovery signal is determined to be the line-of-sight direction.

[0090] Action 330

[0091] In some embodiments disclosed herein the radar-capable device 102, 103 assesses, based on information provided with the radar discovery request, whether the requesting wireless electronic device 101 has rights to be served with the radar sensing data. The information provided with the radar discovery request may comprise authorization information or identity information of the requesting wireless electronic device 101.

[0092] Action 340

[0093] The radar-capable device 102, 103 performs radar sensing in a direction corresponding to the determined direction of arrival of the received radar discovery signal. In some embodiments disclosed herein the direction corresponding to the determined direction of the received radar discovery signal may comprise one or more directions covering the determined angle of arrival of the radar discovery signal. The direction corresponding to the determined direction of the received radar discovery signal may also be a direction range.

[0094] The one or more directions covering the angle of arrival of the radar discovery signal may be a subset of possible radar directions of the radar-capable device 102, 103.

[0095] For example, the radar-capable device 102, 103 may be capable of performing radar sensing omni-directionally, but will cover the angle of arrival by radar beams only in the direction of the angle of arrival.

[0096] In some embodiments disclosed herein the one or more directions covering the angle of arrival of the radar discovery signal are covered by one or more radar beams of the radar-capable device 102, 103 and then an effective half-power beam width of the one or more radar beams cover an angle from 10 to 120 degrees, preferably from 10 to 90 degrees, even more preferably 20 to 45 degrees in at least one coordinate. For example, the radar-capable device 102, 103 may perform radar sensing with beams with an effective half-power beam width of between 20 to 45 degrees, such as 30 degrees, and an effective main lobe direction that coincides with the determined direction of arrival of the received radar discovery signal. Since the radar-capable device 102, 103 performs radar sensing in the direction corresponding to the determined direction of arrival of the received radar discovery signal instead of performing omni-directional radar sensing power can be saved and less data need to be handled.

[0097] The radar-capable device 102, 103 may perform the sensing according to the received specified settings, such as the information indicative of the configuration of radar measurements for the radar sensing, if applicable.

[0098] Action 350

[0099] The radar-capable device 102, 103 transmits radar sensing data from the radar sensing such that the radar sensing data is obtainable by the wireless electronic device 101. Thus, the wireless electronic device 101 wirelessly obtains radar sensing data from the requested radar sensing. The radar sensing data is obtained directly from the radar- capable device 102, 103, or via the data server 110.

[0100] The sensing data may include measurement radar parameters of the performed radar sensing. The sensing data may further include an indication of which capabilities the radar-capable device 102, 103 has in terms of radar sensing parameters, e.g. in terms of sensing characteristics.

[0101] The sensing data may be transmitted directly to the wireless electronic device 101 or to the data server 110 from which the sensing data is obtainable by the wireless electronic device 101.

[0102] In some embodiments disclosed herein the sensing data is transmitted directly to the wireless electronic device 101 in the direction of arrival of the received radar discovery signal.

[0103] In some other embodiments disclosed herein sensing data is transmitted to the data server 110 using a network address of the data server 110 provided with the radar discovery signal.

[0104] The radar-capable device 102, 103 may transmit the radar sensing data encrypted with the encryption key. Thus, the wireless electronic device 101 may wirelessly obtain the radar sensing data encrypted with the encryption key.

[0105] In some embodiments disclosed herein the radar-capable device 102, 103 transmits information on a location of the radar-capable device 102, 103 and on a direction of the performed radar sensing. The radar-capable device 102, 103 may transmit the information on the location of the radar-capable device 102, 103 and on the direction of the performed radar sensing such that the information on the location of the radar-capable device 102, 103 and on the direction of the performed radar sensing is obtainable by the wireless electronic device 101. For example, the radar sensing data may comprise such information or the radar-capable device 102, 103 may transmit this information together with the radar sensing data.

[0106] The sensing data may be transmitted if the radar-capable device 102, 103 is in a specific operational state. If the radar-capable device 102, 103 is not in the specific operational state it may not send the sensing data. The specific operational state of the radar-capable device 102, 103 may be associated with its battery level, activity level, or security level.

[0107] In some embodiments disclosed herein the radar-capable device 102, 103 determines, based on the performed radar sensing, whether there are multiple humans in the direction of the performed radar sensing and then the sensing data is transmitted if it is determined that there isn’t multiple humans in the direction of the performed radar sensing.

[0108] When the radar sensing data is obtained via the data server 110, then the wireless electronic device 101 may further provide, with the radar discovery signal (in action 310 above), information indicative of a network address to the radar-capable device 102, 103 for uploading the radar sensing data to the data server 110. The RD signal may explicitly include the network address, such as an Internet Protocol (IP) address, or it may be an indicator pointing to a previously provided table of addresses or a uniform resource locator (URL) which the radar capable device 102 can use to obtain an IP address via a domain name server lookup, or similar information.

[0109] Action 360

[0110] When the radar sensing data is obtained by receiving the radar sensing data directly from the radar-capable device 102, 103, the method may further comprise determining a direction to the radar-capable device 102, 103 by determining a direction of arrival of the received radar sensing data.

[0111] Action 370

[0112] In some embodiments the wireless electronic device 101 checks whether or not the wireless electronic device 101 still needs sensing.

[0113] Action 380

[0114] If the wireless electronic device 101 does not need sensing anymore the wireless electronic device stops transmitting the radar discovery signal.

[0115] A scenario applicable to some embodiments disclosed herein will now be described. The wireless electronic device 101 will be exemplified with AR glasses. A user is wearing the AR glasses and is located in a room with a number of connected devices in the surrounding, each connected device being capable of radar sensing, possibly with different characteristics. Assume further that the user has not previously been in the room, and the AR glasses does not have any connection to the surrounding devices, e.g. by Bluetooth pairing or similar. The user initiates, or is already executing, an application where external sensing of the user itself or the surrounding is needed or beneficial. The AR glasses transmits a Radar Discovery (RD) signal to the surrounding, e.g. omnidirectional or by multiple transmissions in several directions since there is no information of which devices exist having supporting capabilities. The RD signal may also include identity information of the wireless electronic device 101 as well as a public key so the sensing data may be securely shared in the next step. The RD signal may be carried by a broadcast signal which may be received / decoded by the surrounding radar capable devices. Such a signal may for example be a Bluetooth signal, a Wi-Fi signal or a cellular protocol signal such as NR, LTE or similar. The signal may be transmitted as a broadcasted Bluetooth beacon, a Wi-Fi wake up package, or over another broadcasted transmission channel. In other examples the RD signal may be carried in one or more unicast data or control transmissions to other devices which the electronic device has a wireless connection with. In other words, the RD signal may consist of one or more communication messages inbetween the electronic device 101 and a radar capable device 102, wherein the RD signal may be ordinary payload data communication in-between the devices. Such communication messages may be transmitted as one or more IP based data packages communicated over an application level protocol. In some examples such application level data communication may be using HTTP, TCP-IP protocols or similar. The RD signal may be transmitted as one or more communication messages using such protocols, with any radio access technology I protocol at layers below IP. The RD signal may also include information indicating a requested sensing capability of the radar-capable device 102, 103. The RD signal may be sent on multiple frequency bands and different Radio Access Technologies (RATs) which may be either on licensed or unlicensed spectrum.

[0116] The radar-capable device 102, 103 is configured to listen for the RD signal. Multiple examples of such configuration may be envisioned, including preconfigured, static methods wherein a receiver unit in the radar-capable device 102, 103 is repeatedly listening for RD signals in one or more pre-defined frequency ranges. Technologies for such repeated RD signal monitoring includes on / off keying based wake up signal monitoring, or methods similar to a paging signal in a wireless communication system. Other methods for dynamic control of the monitoring from the radar capable-device 102, 103 includes e.g. a server-based IP data traffic control, wherein the radar capable-device 102, 103 is being configured for monitoring of RD signals (when in time, where in spectrum, how in terms of signal characteristics) by an external server controlling an application or other software function in the radar capable-device 102, 103. The software function in turn may control a radio unit to listen for RD signal accordingly. In some examples this configuration to listen for RD signal is in turn triggered by the need of external sensing as outlined above. The need for external sensing may be notified by the wireless electronic device 101 to the server, which configures one or more radar-capable devices to monitor for RD signals.

[0117] Once configured the radar capable-device 102, 103 may detect the RD signal and determines the direction of the received RD signal using Angle of Arrival (AoA) estimation. In some examples this may include a line-of-sight determination step, to ensure that the wireless electronic device 101 is located in the direction of the received signal. The sensing functionality may in some examples be omitted if the radar-capable device 102, 103 cannot determine Line-of-Sight (LOS). When the AoA has been determined, the radar-capable device 102, 103 then performs the radar sensing in the determined direction of the wireless electronic device 101 and shares the sensing data with the wireless electronic device 101, for example encrypted using the public key and to the device identity provided. The radar sensing may be performed at a different frequency band and with another RAT than the RD signal is using.

[0118] There are several different implementation options for the same principle. The sharing of sensor data may be done e.g. in a broadcast fashion using local, device-centric communication such as a device-to-device communication (e.g. Bluetooth beacon signaling), or by sending the data to a data-sharing service in a datacenter where the wireless electronic device 101 may fetch it. Furthermore, the wireless electronic device 101 responsible for the communication may be the AR glasses, but the AR glasses may be tethered with another device, e.g. a smartphone, which then communicates with the radar capable-devices 102, 103 or with the data-sharing services over the network.

[0119] The RD signal may include further information, such as meta data, to guide the radar-capable device 102, 103 with the radar sensing configuration. This information may suggest characteristics of radar sensing to be performed. Examples include that the RD signal includes or is indicative of a suitable radar signal frequency, pulse length, beamwidth, output power or similar. These parameters may be determined based on an application or a service that needs the radar data and / or based on what kind of data that is needed, e.g. how quickly the user, and thus the wireless electronic device 101, is moving or gesture recognition. The parameters may further be based on whether the wireless electronic device 101 is moving or is stationary. For example, a pulse length may be related to how good timing resolution is needed. A beam width may be related to how good spatial resolution is needed. Bandwidth may be related to how good range resolution is needed. A transmit power may be related to the distance between the wireless electronic device 101 and the radar-capable device 102, 103. Additionally or alternatively the further information may include authorization information or other types of identity or rights so that the radar-capable device 102, 103 have the opportunity to select whether they should serve the request. Further description of how to obtain privacy is provided below.

[0120] After transmitting the RD signal, the wireless electronic device 101 may start a timer which sets a waiting period. During the waiting period, the wireless electronic device 101 expects to receive the sensor data from its surrounding radar capable devices, either via D2D short range communication or from the data server 110. If the timer is expired without any sensor data received, the wireless electronic device 101 may interpret this as no radar capable-device is available in its current surrounding. It may then stop sending any more RD signals or send RD signals with a longer range.

[0121] Note that in embodiments disclosed herein, there is no need for the wireless electronic device 101 to perform any pairing with the surrounding radar-capable devices 102, 103, and the wireless electronic device 101 need no additional access to those devices , e.g. to their other functionalities or their data or settings.

[0122] Whereas the above scenario is a typical scenario of embodiments disclosed herein, there are many alternative embodiments described below.

[0123] Consent and privacy aspects

[0124] In action 330 described above, depending on the specific embodiment, additional actions may be performed which will be described in more detail now.

[0125] In one embodiment, the radar-capable device 102, 103 only supports radar service for authorized devices or in authorized places. For example, in a conference room of a company, the service may be limited to employee devices.

[0126] In another embodiment, the radar-capable device 102, 103 assesses whether there is only one person in the beam direction of the sensing, and in case of multiple people the radar-capable device 102, 103 does not share sensor data for privacy reasons, or it may request consent from the devices in an area. In another embodiment, if more than one person is detected, and if the distance from the requesting wireless electronic device 101 is sufficient and the angular difference is sufficient to identify the requesting wireless electronic device 101 or requesting person with high confidence, only objects near the requesting wireless electronic device 101 or user is reported.

[0127] In another embodiment, the signal strength of the RD signal is compared to what would be expected for line-of-sight communication from the person identified by the radar as sending the request. As the radar has measured the distance to the person the path loss for line-of-sight is known. If the signal is much weaker than that, the wireless electronic device 101 and the radar-capable device 102, 103 are likely not in the same room, and the result of the radar operation may not be reported to the requesting device.

[0128] In yet another embodiment, the characteristics of the radar sensing may be set depending on a few different cases: the RD signal may indicate certain specifics of the sensing to be performed to be of maximum use, or the characteristics of the sensing may depend on distance to the wireless electronic device 101 or the user, etc. Examples of such settings may be frequency, bandwidth, etc.

[0129] Furthermore, it may be that the radar-capable device 102, 103 is in full use of its resources and cannot support the sensing request for the moment.

[0130] As mentioned above for action 350, the radar-capable device 102, 103 may transmit the sensor data to the wireless electronic device 101 , e.g. encrypted. In addition, relevant meta data related to the characteristics of the sensing, position of the sensor device, etc may also be shared with the wireless electronic device 101.

[0131] When sharing the sensing data with the wireless electronic device 101 , it may be preferred to attach certain meta data to the sensing data stream. Examples include:

[0132] • Characteristics of the sensing: e.g. type of sensor (radar, lidar, camera, ultrasound), frequency, bandwidth, output power, beam characteristics, etc.

[0133] • Timestamp

[0134] • Location of the radar device (if known)

[0135] • Relative direction of the radar-capable device 102, 103 to the wireless electronic device 101. In case of direct communication from the radar-capable device 102, 103 to the wireless electronic device 101 , this may be solved by AoA or similar approaches. In case of sensing data sharing via a cloud service, this can either be solved by certain messaging between the devices to determine relative direction, or via location information (assuming both devices knows their position). Furthermore, if the radar-capable device 102, 103 knows its location and direction to the wireless electronic device 101 , this information may be shared.

[0136] In some use cases, the user needs continuous sensing support. This may either be supported by constant distribution of the RD signal (exemplified by actions 360 and 370 in Figure 3) or by indications in the RD signal of the periodicity and duration required.

[0137] Authorization and denial of service

[0138] In some use cases, certain areas may be restricted so that only authorized devices may make use of the radar service, e.g. an office environment with potentially sensitive equipment, or in a home environment for privacy reasons. Therefore, some embodiments allow the requesting wireless electronic device 101 to provide an identity or authorization code with the RD request, or to support an authorization procedure, before the radar- capable device 102, 103 will perform the actual sensing. In some embodiment, this is determined by allowing only pre-authorized wireless electronic device 101 , whereas in other embodiments the service is allowed for wireless electronic devices having certain codes or keys. In yet another embodiment, such authorization depends on the type of sensor or sensing capabilities of the radar-capable device 102, 103, e.g. allowing radar to be performed for all requesting wireless electronic devices whereas only authorized requesting wireless electronic devices can get access to peer camera sensor data.

[0139] Snapshot-sensing vs. Continuous sensing

[0140] Whereas the above description is based on the assumption that one RD request leads to one sensing action by the involved radar-capable devices 102, 103, there are other scenarios possible depending on implementation. In some use cases, user devices such as XR headsets needs sensing over a period of time, e.g. to detect movements or gestures. In some embodiments, the wireless electronic device 101 may transmit a series of RD requests to get a sequence of sensing data allowing it to detect movements or sequences of events. In another embodiment, the RD request contains meta data on the type of request which may be to perform a series of radar sensing over a certain period of time. Further embodiments

[0141] In some embodiments, the RD request contains specific commands for certain types of sensing. This may include micro Doppler sensing, range sensing, or in some cases also synthetic-aperture radar sensing, depending on the capabilities of the radar-capable device 102, 103.

[0142] In other embodiments, the radar-capable device 102, 103 may respond with meta data on which capabilities it has, allowing the requesting wireless electronic device 101 to further specify or request certain features or characteristics of the sensing. This may also include other sensing capabilities than radar in addition to the radar sensing.

[0143] Figure 4 illustrates further optional details of the wireless electronic device 101. Figure 5 illustrates further optional details of the radar-capable device 102, 103. The wireless electronic device 101 and the radar-capable device 102, 103 are configured to perform the method actions of Figure 3 above.

[0144] Thus, the wireless electronic device 101 is configured for radar sensing.

[0145] The wireless electronic device 101 is further configured to wirelessly transmit the radar discovery signal to the radar-capable device 102, 103. The radar discovery signal is indicative of the request for radar sensing to be performed by the radar- capable device 102, 103. The radar sensing is requested to be performed in the direction corresponding to an angle of arrival of the radar discovery signal as seen by the radar-capable device 102, 103.

[0146] The wireless electronic device 101 is further configured to wirelessly obtain radar sensing data from the requested radar sensing.

[0147] The wireless electronic device 101 may be further configured to obtain the radar sensing data directly from the radar-capable device 102, 103, or via the data server 110.

[0148] In some embodiments herein the wireless electronic device 101 is further configured to obtain the radar sensing data via the data server 110. Then the wireless electronic device 101 may be further configured to provide, with the radar discovery signal, information indicative of the network address to the radar-capable device 102, 103 for uploading the radar sensing data to the data server 110. In some embodiments disclosed herein the wireless electronic device 101 is further configured to transmit an encryption key with the radar discovery signal to the radar- capable device 102, 103, and receive the radar sensing data encrypted with the encryption key.

[0149] The wireless electronic device 101 may be further configured to transmit the radar discovery signal to the radar-capable device 102, 103 by transmitting the request for repeated radar sensing during a time period.

[0150] In some embodiments disclosed herein the wireless electronic device 101 is further configured to transmit the radar discovery signal to the radar-capable device 102, 103 by transmitting information indicative of the configuration of radar measurements for the radar sensing.

[0151] When the wireless electronic device 101 is configured to obtain the radar sensing data by receiving the radar sensing data directly from the radar-capable device 102, 103 the wireless electronic device 101 may be further configured to determine the direction to the radar-capable device 102, 103 by determining the direction of arrival of the received radar sensing data.

[0152] The radar-capable device 102, 103 is configured for radar sensing. The radar- capable device 102, 103 is further configured to wirelessly receive the radar discovery signal transmitted from the wireless electronic device 101.

[0153] The radar-capable device 102, 103 is further configured to determine the direction of arrival of the received radar discovery signal.

[0154] The radar-capable device 102, 103 is further configured to perform radar sensing in the direction corresponding to the determined direction of arrival of the received radar discovery signal.

[0155] The radar-capable device 102, 103 is further configured to transmit radar sensing data from the radar sensing such that the radar sensing data is obtainable by the wireless electronic device 101.

[0156] The radar-capable device 102, 103 may be further configured to transmit the sensing data directly to the wireless electronic device 101 or to the data server 110 from which the sensing data is obtainable by the wireless electronic device 101. In some embodiments disclosed herein the radar-capable device 102, 103 is further configured to transmit the sensing data directly to the wireless electronic device 101 in the direction of arrival of the received radar discovery signal.

[0157] The radar-capable device 102, 103 may be further configured to transmit the sensing data to the data server 110 using the network address of the data server 110 provided with the radar discovery signal.

[0158] In some embodiments disclosed herein the radar-capable device 102, 103 is further configured to receive an encryption key with the radar discovery signal and transmit the radar sensing data encrypted with the encryption key.

[0159] The radar-capable device 102, 103 may be further configured to determine the direction of arrival of the received radar discovery signal by being configured to determine whether the direction of arrival of the received radar discovery signal is the line-of-sight direction. Then the following steps after the determination of the direction of arrival may be performed only if the direction of arrival of the received radar discovery signal is determined to be the line-of-sight direction.

[0160] In some embodiments disclosed herein the radar-capable device 102, 103 is further configured to transmit information on the location of the radar-capable device 102, 103 and on the direction of the performed radar sensing.

[0161] The radar-capable device 102, 103 may be further configured to assess, based on information provided with the radar discovery request, whether the requesting wireless electronic device 101 has rights to be served with the radar sensing data.

[0162] In some embodiments disclosed herein the radar-capable device 102, 103 is further configured to transmit the sensing data if the radar-capable device 102, 103 is in a specific operational state.

[0163] The radar-capable device 102, 103 may be further configured to determine, based on the performed radar sensing, whether there are multiple humans in the direction of the performed radar sensing. Then the sensing data may be transmitted if it is determined that there isn’t multiple humans in the direction of the performed radar sensing.

[0164] The embodiments herein may be implemented through a processor or one or more processors, such as the processor 404, 504 of a processing circuitry in the respective wireless electronic device 101 and radar-capable device 102, 103, depicted in Figure 4 and 5, together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the respective wireless electronic device 101 and radar-capable device 102, 103. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the respective wireless electronic device 101 and radar-capable device 102, 103.

[0165] The respective wireless electronic device 101 and radar-capable device 102, 103 may further comprise a memory 402, 502 comprising one or more memory units. The memory comprises instructions executable by the processor in the respective wireless electronic device 101 and radar-capable device 102, 103.

[0166] The respective memory 402, 502 is arranged to be used to store e.g. information, data, configurations, and applications to perform the methods herein when being executed in the respective wireless electronic device 101 and radar-capable device 102, 103.

[0167] In some embodiments, a computer program 403, 503 comprises instructions, which when executed by the at least one processor, cause the at least one processor of the respective wireless electronic device 101 and radar-capable device 102, 103 to perform the actions above.

[0168] In some embodiments, a carrier 405, 505 comprises the computer program, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium. The respective wireless electronic device 101 and radar-capable device 102, 103 may further comprise an input and output interface, I / O, 406, 506 configured to communicate with other devices. Those skilled in the art will also appreciate that the units described above may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g. stored in the transceiver node 501 , that when executed by the respective one or more processors such as the processors described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a system-on-a-chip (SoC).

[0169] When using the word "comprise" or “comprising” it shall be interpreted as non- limiting, i.e. meaning "consist at least of".

[0170] The embodiments herein are not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used.

Claims

CLAIMS1. A method, performed by a wireless electronic device (101), for radar sensing, the method comprising: wirelessly transmitting (310) a radar discovery signal to a radar-capable device (102, 103), wherein the radar discovery signal is indicative of a request for radar sensing to be performed by the radar-capable device (102, 103) and wherein the radar sensing is requested to be performed in a direction corresponding to an angle of arrival of the radar discovery signal as seen by the radar-capable device (102, 103), and wirelessly obtaining (350) radar sensing data from the requested radar sensing.

2. The method according to claim 1 , wherein the radar sensing data is obtained directly from the radar-capable device (102, 103), or via a data server (110).

3. The method according to claim 2, wherein the radar sensing data is obtained via the data server (110), and further comprising providing, with the radar discovery signal, information indicative of a network address to the radar-capable device (102, 103) for uploading the radar sensing data to the data server (110).

4. The method according to any of the claims 1-3, further comprising: transmitting an encryption key with the radar discovery signal to the radar- capable device (102, 103), and wirelessly obtaining (350) the radar sensing data encrypted with the encryption key.

5. The method according to any of the claims 1-4, wherein transmitting (310) the radar discovery signal to the radar-capable device (102, 103) comprises transmitting a request for repeated radar sensing during a time period.

6. The method according to any of the claims 1-5, wherein transmitting (310) the radar discovery signal to the radar-capable device (102, 103) comprises transmitting information indicative of a configuration of radar measurements for the radar sensing.

7. The method according to any of the claims 1-6, wherein the direction corresponding to the angle of arrival of the radar discovery signal comprises one or more directions covering the angle of arrival of the radar discovery signal, and wherein the one or more directions covering the angle of arrival of the radar discovery signal is a subset of possible radar directions of the radar-capable device (102, 103).

8. The method according to claim 7, wherein the one or more directions covering the angle of arrival of the radar discovery signal are covered by one or more radar beams of the radar-capable device (102, 103) and wherein an effective half-power beam width of the one or more radar beams cover an angle from 10 to 120 degrees, preferably from 10 to 90 degrees, even more preferably 20 to 45 degrees in at least one coordinate.

9. The method according to any of the claims 1-8, wherein the radar sensing data is obtained by receiving the radar sensing data directly from the radar-capable device (102, 103), and the method further comprises: determining (360) a direction to the radar-capable device (102, 103) by determining a direction of arrival of the received radar sensing data.

10. A method, performed by a radar-capable device (102, 103), for radar sensing, the method comprising: wirelessly receiving (310) a radar discovery signal transmitted from a wireless electronic device (101), determining (320) a direction of arrival of the received radar discovery signal, performing (340) radar sensing in a direction corresponding to the determined direction of arrival of the received radar discovery signal, and transmitting (350) radar sensing data from the radar sensing such that the radar sensing data is obtainable by the wireless electronic device (101).

11. The method according to claim 10, wherein the sensing data is transmitted directly to the wireless electronic device (101) or to a data server (110) from which the sensing data is obtainable by the wireless electronic device (101).

12. The method according to claim 10 or 11, wherein the sensing data is transmitted directly to the wireless electronic device (101) in the direction of arrival of the received radar discovery signal.

13. The method according to claim 11 , wherein the sensing data is transmitted to the data server (110) using a network address of the data server (110) provided with the radar discovery signal.

14. The method according to any of the claims 10-13, further comprising: receiving (310) an encryption key with the radar discovery signal and transmitting the radar sensing data encrypted with the encryption key.

15. The method according to any of the claims 10-14, wherein determining the direction of arrival of the received radar discovery signal includes determining whether the direction of arrival of the received radar discovery signal is a line-of-sight direction, and wherein the following steps after the determination of the direction of arrival are performed only if the direction of arrival of the received radar discovery signal is determined to be the line-of-sight direction.

16. The method according to any of the claims 10-15, further comprising transmitting information on a location of the radar-capable device (102, 103) and on a direction of the performed radar sensing.

17. The method according to any of the claims 10-16, wherein the sensing data includes measurement radar parameters of the performed radar sensing.

18. The method according to any of the claims 10-17, wherein the sensing data includes an indication of which capabilities the radar-capable device (102, 103) has in terms of radar sensing parameters.

19. The method according to any of the claims 10-18, further comprising assessing (330) based on information provided with the radar discovery request, whether the requesting wireless electronic device (101) has rights to be served with the radar sensing data.

20. The method according to claim 19, wherein the information provided with the radar discovery request comprises authorization information or identity information of the requesting wireless electronic device (101).

21. The method according to any of the claims 10-20, wherein the sensing data is transmitted if the radar-capable device (102, 103) is in a specific operational state.

22. The method according to any of the claims 10-21 , further comprising determining, based on the performed radar sensing, whether there are multiple humans in the direction of the performed radar sensing and wherein the sensing data is transmitted if it is determined that there isn’t multiple humans in the direction of the performed radar sensing.

23. The method according to any of the claims 10-22, wherein the direction corresponding to the determined direction of the received radar discovery signal comprises one or more directions covering the determined angle of arrival of the radar discovery signal, and wherein the one or more directions covering the angle of arrival of the radar discovery signal is a subset of possible radar directions of the radar-capable device (102, 103).

24. The method according to claim 23, wherein the one or more directions covering the angle of arrival of the radar discovery signal are covered by one or more radar beams of the radar-capable device (102, 103) and wherein an effective half-power beam width of the one or more radar beams cover an angle from 10 to 120 degrees, preferably from 10 to 90 degrees, even more preferably 20 to 45 degrees in at least one coordinate.

25. A computer program (403), comprising computer readable code units which when executed on a computer causes the computer to perform the method according to any one of claims 1-9.

26. A computer program (503), comprising computer readable code units which when executed on a computer causes the computer to perform the method according to any one of claims 10-24.

27. A carrier (405, 505) comprising the computer program according to any one of claims 25-26, wherein the carrier (405, 505) is one of an electronic signal, an optical signal, a radio signal and a computer readable medium.

28. A wireless electronic device (101) configured for radar sensing, and further configured to: wirelessly transmit a radar discovery signal to a radar-capable device (102, 103), wherein the radar discovery signal is indicative of a request for radar sensing to be performed by the radar-capable device (102, 103) and wherein the radar sensing is requested to be performed in a direction corresponding to an angle of arrival of the radar discovery signal as seen by the radar-capable device (102, 103), and wirelessly obtain radar sensing data from the requested radar sensing.

29. The wireless electronic device (101) according to claim 28, further configured to perform the method of any of the claims 2-9.

30. A radar-capable device (102, 103) for radar sensing, and further configured to: wirelessly receive a radar discovery signal transmitted from a wireless electronic device (101), determine a direction of arrival of the received radar discovery signal, perform radar sensing in a direction corresponding to the determined direction of arrival of the received radar discovery signal, and transmit radar sensing data from the radar sensing such that the radar sensing data is obtainable by the wireless electronic device (101).

31. The radar-capable device (102, 103) according to claim 30, further configured to perform the method of any of the claims 11-24.

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