Wireless transceiver for joint monostatic radar sensing and data communication

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

[0001] WIRELESS TRANSCEIVER FOR JOINT MONOSTATIC RADAR SENSING AND DATA

[0002] COMMUNICATION

[0003] TECHNICAL FIELD

[0004] The embodiments herein relate to a wireless transceiver for joint monostatic radar sensing and data communication and a method for joint monostatic radar sensing and data communication. A corresponding computer program and a computer program carrier are also disclosed.

[0005] BACKGROUND

[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] Joint communication and sensing (JCAS)

[0008] Use of communication jointly with sensing (such as radar) is an efficient way of improving the performance of communication systems or of providing additional services, such as surveillance. JCAS is a key technology envisioned for 6G. Millimeter wave / sub- THz frequencies are of particular interest for implementing JCAS, due to large bandwidths and sharp beams enabling high 3D resolution of localization and mapping. A basic idea with JCAS is reusing parts of or all of the radio hardware and signaling used for data communication to also support radar functionality.

[0009] To this end, communication signals (carrying data transmissions) may be reused as radar signals. Other signals, such as various reference signals (e.g. CSI-RS, SSB, DM RS) may also be used as radar signals. There are two basic setups for radar: monostatic and bistatic / multistatic radar. In monostatic radar, transmitter and receiver are co-located. In bi / multistatic radar, the receiver is not co-located with the transmitter, i.e. receiver and transmitter are part of different units, for instance in different base-stations or different user equipments (UEs). However, there are some problems related to existing JCAS technology. For example, monostatic radar requires full duplex operation and high levels of Tx-Rx leakage suppression.

[0010] At high frequencies where analog beam steering is used, the communication signal is typically transmitted in one direction, which limits simultaneous radar functionality: typical radar applications require transmitting the radar signal in different directions.

[0011] The above may be solved by splitting the transmit phased array in two subarrays and simultaneously transmitting communication data using one subarray and radar signal with the other subarray. But a link budget for both radar and communication will be compromised in this solution.

[0012] Using reference signals as radar signals may be suboptimal as reference signals may not have the correct temporal density or duration for e.g. estimating the velocity of moving targets.

[0013] Further, at high carrier frequencies the electromagnetic wavelength is short. At 300 GHz the wavelength is just 1 mm. Antenna elements then also get small, and to reach practical communication distances rather large array antennas (with a large number of antenna elements) may be needed. At 300 GHz a half wavelength spacing corresponds to 0.5 mm, so a square centimeter sized array will fit 400 antenna elements. It becomes power consuming to drive so many antenna elements with a wideband and phase coherent signal to transmit or receive high data-rate signals.

[0014] SUMMARY

[0015] There is thus a need for a more efficient approach for implementing JCAS. This may be of particular interest at high frequencies where antenna arrays are used for increased antenna gain.

[0016] An object of embodiments herein may be to obviate some of the problems related to JCAS operation of a wireless transceiver, specifically at high frequencies.

[0017] An alternative at high frequencies is to use a lens to increase the antenna gain. Although lenses are commonly associated with receive / transmit focusing of light, they may be used for other types of EM radiation, which includes RF EM waves. A Dielectric Lens Antenna (DLA), made from e.g. silicon may be used for this purpose.

[0018] Embodiments herein disclose electronic devices and methods for joint monostatic radar sensing and data communication based on switched-beam lens antennas. According to a first aspect, the object is achieved by a wireless transceiver for joint monostatic radar sensing and data communication. The wireless transceiver comprises a wireless transmitter for transmission of data signals and radar signals and a wireless receiver for reception of data signals and radar signals.

[0019] The wireless transmitter comprises a first transmitter baseband circuit for data signals, a second transmitter baseband circuit for radar signals and a first switched-beam lens antenna. The first switched-beam lens antenna comprises multiple transmitter antenna ports and a first lens for beam forming a respective transmit beam from the multiple transmitter antenna ports.

[0020] The wireless receiver comprises a first receiver baseband circuit for data signals, a second receiver baseband circuit for radar signals and a second switched-beam lens antenna. The second switched-beam lens antenna comprises multiple receiver antenna ports and a second lens for beam forming a respective receive beam to the multiple receiver antenna ports.

[0021] According to a second aspect, the object is achieved by a wireless transceiver node comprising the wireless transceiver according to the first aspect. As mentioned above, the wireless transceiver comprises a first switched-beam lens antenna for transmission of data signals and radar signals and a second switched-beam lens antenna for reception of data signals and radar signals.

[0022] According to a third aspect, the object is achieved by a method, performed by a wireless transceiver node according to the second aspect. The method is for joint monostatic radar sensing and data communication. The wireless transceiver comprises a wireless transmitter for transmission of data signals and radar signals and a wireless receiver for reception of data signals and radar signals. The wireless transmitter comprises a first switched-beam lens antenna and the wireless receiver comprises a second switched-beam lens antenna.

[0023] The method comprises transmitting data signals in a first beam direction using the wireless transmitter.

[0024] The method further comprises transmitting and receiving radar signals in a second beam direction which differs from the first beam direction while transmitting the data signals in the first beam direction. The transmission of radar signals is performed using the wireless transmitter, while the reception of radar signals is performed using the wireless receiver. 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.

[0025] 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.

[0026] Since the wireless transceiver comprises the first switched-beam lens antenna for transmission of data signals and radar signals and the second switched-beam lens antenna for reception of data signals and radar signals the wireless transceiver is able to perform efficient and flexible joint monostatic radar operation and data communication with low power consumption and low interference between the data communication signals and the radar signal. For example, the wireless transceiver is able to transmit and receive data signals in one direction using first transmitter and receiver antenna ports and simultaneously transmit and receive radar signals in a second direction using second transmitter and receiver antenna ports. Separation of data and radar signals in spatial domain ensures low interference.

[0027] A reason for choosing a switched-beam lens antenna over a phased array is power consumption. In a transmit phased array, each antenna will typically have an associated Power Amplifier (PA) placed right after the antenna. Therefore, for an array with N antennas, power consumption of the amplifier section is Nx power consumption of one PA. In contrast, switched-beam lens antenna only has one PA activated at a time, so power consumption of the amplifier part is a factor of N smaller than in the phased array. By reciprocity, same power consumption benefit of the switched-beam lens antenna holds for a receiving antenna. The switched-beam lens antenna has additional benefits, such as lack of phase shifters and consequently no beam squint problem at high relative bandwidths. However, a total radiated output power will be less compared to operating many transmit branches. Switched-beam lens antennas are a particularly attractive solution at very high frequencies (e.g. high mmWave, 100 - 300 GHz) due to a beneficial ratio between physical size and gain at the very high frequencies. 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 1a is a block diagram schematically illustrating a lens and a boresight focal point,

[0031] Figure 1b is a block diagram schematically illustrating a lens and a further focal point,

[0032] Figure 2a is a block diagram schematically illustrating a switched-beam lens antenna for a transmitter,

[0033] Figure 2b is a block diagram schematically illustrating a further switched-beam lens antenna for a receiver,

[0034] Figure 3a is a block diagram schematically illustrating a transceiver according to some embodiments herein,

[0035] Figure 3b is a further block diagram schematically illustrating switched-beam lens antennas according to some embodiments herein,

[0036] Figure 4 is a flowchart illustrating embodiments of a method according to some embodiments herein,

[0037] Figure 5 is a block diagram schematically illustrating a transceiver node according to some embodiments herein,

[0038] Figure 6a is a block diagram schematically illustrating details of a method according to some embodiments herein,

[0039] Figure 6b is a block diagram schematically illustrating details of a method according to some further embodiments herein,

[0040] Figure 7 is a block diagram schematically illustrating further details of a method according to some embodiments herein,

[0041] Figure 8 is a block diagram schematically illustrating a transceiver according to some alternative embodiments herein,

[0042] Figure 9 is a block diagram schematically illustrating a wireless communication system.

[0043] DETAILED DESCRIPTION Embodiments herein relate to JCAS. As mentioned above a lens may be used to increase the antenna gain. For example, a transmit lens may be used to collimate electromagnetic (EM) radiation generated at a point source located at a focal point of the lens into a planar EM wave front. Radiation generated at different focal points will be transmitted in different directions, which correspond to transmit beams.

[0044] Naturally, a lens may also be used in reception mode, to focus EM radiation coming from a specific angle onto a focal point of the lens.

[0045] Figure 1a and Figure 1b shows a principle of EM radiation collimation using a lens. In Figure 1a, radiation generated in focal point fi is transmitted in boresight. In Figure 1b, radiation generated in focal point f2 is transmitted in an off-boresight angle.

[0046] Thus, lenses may be used for an efficient implementation of RF beam steering. Antenna elements may be placed in the focal points of the lens, forming an antenna array. By selecting one particular antenna element, and thus a particular port, for transmission, one effectively steers the transmit beam in a direction corresponding to the focal point the antenna is located at. An antenna element and an RF circuitry connected to the antenna element, such as at least a power amplifier or a low-noise amplifier, may be defined as an antenna port. Thus, the selection of the antenna element may also be seen as a selection of the corresponding antenna port and vice versa. The same principle holds for receive beam steering - choosing one particular antenna port for reception, the RF radiation from a particular direction will be onto an antenna sitting in a focal point of the lens. The joint structure of antenna array with antenna selection and lens may be referred to as a switched-beam lens antenna.

[0047] The gain of a lens at 300 GHz has been investigated in prior art. A lens antenna of just 10 mm diameter may have a gain of more than 25 dBi. At these high frequencies high gain may thus be obtained from very small lenses, suitable for use also in lightweight portable devices.

[0048] A principle of transmit operation of a switched-beam lens antenna 201 is illustrated in Figure 2a. Antennas Ai - A4 are located at a focal plane of a lens 210. If an output signal of a power amplifier 220 is switched to antenna A1 , the antenna radiation is collimated by the lens 210 resulting in beam Bi , if antenna A2 is used this results in beam B2, and so on. The power amplifier 220 may be connected to an RF front end 230 and a digital baseband 240.

[0049] Figure 2b illustrates a principle of receive operation of a second switched-beam lens antenna 202. The second switched-beam lens antenna 202 of Figure 2b may correspond to the switched-beam lens antenna 201 in Figure 2a. However, the second switched- beam lens antenna 202 of Figure 2b is for receiving signals. The switched-beam lens antenna 202 of Figure 2b comprises a receive lens 204. In Figure 2b a first antenna element 214 of the multiple antenna elements is connected to a Low-Noise Amplifier LNA 261. The LNA 261 and the antenna element 214 are jointly referred to in the following as an antenna port. In Figure 2b each antenna port is connected to an LNA. Selection of an antenna port may then be performed by activating the LNA 261 connected to the antenna element, and connecting the antenna port to an RF front end 231 and a digital baseband 211.

[0050] An alternative antenna selection design may feature as many RF front ends as there are antenna ports and switching on an antenna port would comprise activating the corresponding RF front end and LNA, which may be referred to as an RF chain. The activation may be made electronically. The same principle applies to a transmit lens, where e.g. an RF front end in combination with a power amplifier and an antenna may constitute a port. The latter architecture is preferred at higher frequencies since switches are to be avoided due to their large losses; the former architecture is referred to and featured in figures herein for its simplicity of representation.

[0051] Antennas may be arranged in a 2D array which enables beamforming in both azimuth and elevation. Several antennas may be chosen simultaneously which widens the beam.

[0052] Placing an antenna array at or near the focal plane of the lens, a beam may still be steered over some range. But a single antenna element may be active rather than the full array, alleviating problems like signal phase coherency, and combination. The power consumption may be reduced substantially, by an order of magnitude or more.

[0053] Embodiments herein disclose a transceiver based on switched beam antenna lenses for joint monostatic radar operation and data communication. Specifically, while the data signal is transmitted in one direction using one antenna port, unused antenna ports are used for transmission of radar signals. Likewise, idle antenna ports of a receiver antenna lens are used for the reception of the radar signals.

[0054] Thus, embodiments herein disclose a switched beam lens antenna arrangement of a wireless transceiver used for simultaneous communication and sensing. The wireless transceiver comprises one lens used for transmission (Tx) and one for reception (Rx). The data communication may operate in full duplex (FD) or in time division duplex (TDD). For the data communication signal, antenna ports corresponding to the data communication beam direction are used in the Tx and Rx antenna lenses. Other antenna ports may be used by the radar sensing, for radar measurements in different beam directions. When data communication is TDD, the radar may operate when communication is in Tx mode, without radar to data communication self-interference. Still data communication to radar self-interference may need cancellation if data transmission and radar transmission / reception share the same frequency resources. If data communication is also in full-duplex, it may need radar to data communication self-interference cancellation.

[0055] In order to avoid a radar blind spot in the communication direction, the communication signal may be used for sensing that direction. Alternatively, if communicating in TDD, the radar signal may be sent from the Tx lens in the communication direction, while the communication is in Rx mode, with proper selfinterference cancellation. Alternatively, if communicating in full duplex, the communication transmission may be interrupted to transmit the radar signal. These considerations also apply to the beams adjacent to the communication beam, to avoid signal quality degradation when the signal reaches the intended receiver (communication or radar) due to insufficient spatial separation between the e.g. transmit data signal and receive radar signal occupying two adjacent beams.

[0056] Figure 3a schematically illustrates a wireless transceiver 300 for joint monostatic radar sensing and data communication. Note that in embodiments herein data communication also covers signalling between two wireless nodes. The signalling may be between a wireless communications device and a network node for example.

[0057] The wireless transceiver 300 comprises a wireless transmitter 301 for transmission of data signals and radar signals.

[0058] . The wireless transmitter 301 comprises a first transmitter baseband circuit 312 for data signals and a second transmitter baseband circuit 313 for radar signals. The first transmitter baseband circuit 312 may be dedicated for data signals and the second transmitter baseband circuit 313 may be dedicated for radar signals. Thus, in some embodiments herein the first transmitter baseband circuit 312 is not configured for radar signals and the second transmitter baseband circuit 313 is not configured for data signals.

[0059] The wireless transmitter 301 further comprises a first switched-beam lens antenna 303. The first switched-beam lens antenna 303 comprises multiple transmitter antenna ports 314-317. Each of the transmitter antenna ports 314-317 may serve to support either data communication or radar sensing.

[0060] The first switched-beam lens antenna 303 further comprises a first lens 319 for beam forming a respective transmit beam from the multiple transmitter antenna ports 314- 317.

[0061] The wireless transceiver 300 further comprises a wireless receiver 302 for reception of data signals and radar signals. The wireless receiver 302 comprises a first receiver baseband circuit 322 for data signals and a second receiver baseband circuit 323 for radar signals.

[0062] The wireless receiver 302 further comprises a second switched-beam lens antenna 304 comprising multiple receiver antenna ports 324-327 and a second lens 329 for beam forming a respective receive beam to the multiple receiver antenna ports 324-327. Each of the receiver antenna ports 324-327 may serve to support either data communication or radar sensing.

[0063] A respective transmitter antenna port 314-317 and a respective receiver antenna port 324-327 may comprise a radio-frequency circuit 331, 332, 351, 352 and an antenna element 341, 342, 361, 362 as depicted in Figure 3b.

[0064] The first transmitter baseband circuit 312 and the second transmitter baseband circuit 313 may each be operationally connected to the first switched-beam lens antenna 303. Correspondingly, the first receiver baseband circuit 322 and the second receiver baseband circuit 323 may each be operationally connected to the second switched-beam lens antenna 304.

[0065] For example, the wireless transmitter 301 may be configured to operationally connect the first transmitter baseband circuit 312 to at least a first transmitter antenna port 314 of the multiple transmitter antenna ports 314-317, and the wireless transmitter 301 may be further configured to operationally connect the second transmitter baseband circuit 313 to at least a second transmitter antenna port 315 of the multiple transmitter antenna ports 314-317.

[0066] At a later time, the wireless transmitter 301 may be configured to operationally connect the first transmitter baseband circuit 312 to at least the second transmitter antenna port 315 and to operationally connect the second transmitter baseband circuit 313 to the first transmitter antenna port. The wireless transceiver may use any unused antenna port for transmitting the radar signals. Correspondingly, the wireless receiver 302 may be configured to operationally connect the first receiver baseband circuit 322 to at least a first receiver antenna port 324 of the multiple receiver antenna ports 324-327, and the wireless receiver 302 may be further configured to operationally connect the second receiver baseband circuit 323 to at least a second receiver antenna port 325 of the multiple receiver antenna ports 324-327.

[0067] Thus, at least a first transmitter antenna port 314 of the multiple transmitter antenna ports 314-317 may be operationally connected to the first transmitter baseband circuit 312 and at least a second antenna port 315 of the multiple transmitter antenna ports 314-317 may be operationally connected to the second transmitter baseband circuit 313.

[0068] Further, at least a first receiver antenna port 324 of the multiple receiver antenna ports 324-327 may be operationally connected to the first receiver baseband circuit 322 and at least a second receiver antenna port 325 of the multiple receiver antenna ports 324-327 may be operationally connected to the second receiver baseband circuit 323.

[0069] In some embodiments herein the multiple transmitter antenna ports 314-317 comprise further second transmitter antenna ports 316-317 and then the second transmitter baseband circuit 313 may be configured to be sequentially operationally connected to the second transmitter antenna ports 315-317. Correspondingly, the multiple receiver antenna ports 324-327 may comprise further second receiver antenna ports 326- 327 and then the second receiver baseband circuit 323 may be configured to be sequentially operationally connected to the second receiver antenna ports 325-327.

[0070] In some embodiments herein the wireless transmitter 301 is configured to transmit and receive the data signals in a first beam direction BT 1 , BR1 and to transmit and receive the radar signals in a second beam direction BT2-BT4, BR2-BR4 which differs from the first beam direction BT 1. Then the wireless transmitter 301 may be configured to transmit the radar signals while it transmits the data signals. Thus, the wireless transceiver 300 may be configured to transmit radar signals in a time slot for data communication transmission, thereby reusing the beamforming apparatus and time / frequency resources for data to support radar operation.

[0071] A first receive beam direction BR1 may be the same or correspond to a first transmit beam direction BT1. Correspondingly, a second receive beam direction BR2-BR4 may be the same or correspond to a second transmit beam direction BT2-BT4. In some other embodiments, the wireless transmitter 301 is further configured to transmit the radar signals in the first beam direction BT1, and then the wireless transmitter 301 is configured to interrupt the transmission of the data signals while it transmits the radar signals in the first beam direction BT1. Thus, the wireless transceiver 300 may be configured to interrupt transmission of data communication signals while transmitting radar signals in a direction used for data communication or neighbor beams.

[0072] The wireless transmitter 301 may be further configured to transmit the radar signals in the first beam direction BT 1 while the wireless transceiver (300) receives the data signals in the first beam direction BT 1. Thus, the wireless transceiver 300 may be configured to transmit radar in a time slot for reception of data communication, to allow radar sensing in the communication direction, or neighbor beams, without interrupting communication. Transmitting radar in the time slot for reception of data communication may need radar to communication interference cancellation. Such cancellation will be described below.

[0073] In some embodiments, the wireless transmitter 301 is further configured to use the data signals for radar sensing in the first beam direction BT1. In other words, the wireless transceiver 300 may be configured to use the data communication signal in the direction of the data communication, or in neighbor beams for radar sensing to avoid having to transmit a dedicated radar signal there.

[0074] The second lens 329 may be separated from the first lens 319. By separating reception and transmission into different antenna lenses, isolation between transmitted signals and received signals is improved, compared to using one antenna lens for transmission and reception of data communication and another lens for transmission and reception of radar signals.

[0075] A distance between the lenses may depend on communication and sensing distances, data rates, radar cross sections, frequency of the signals, and bandwidth of the signals. The separation may be on the order of one to ten lens diameters. The lens diameter may be a lens diameter of the first lens 319 or of the second lens 329.

[0076] Further, absorbers or metal structures or both may be placed between the first lens 319 and the second lens 329 to improve the isolation between them.

[0077] In some embodiments the second lens 329 is arranged such that an axis of the second lens 329 is at a distance from an axis of the first lens 319 by at least one diameter of the first lens 319 or the second lens 329, preferably the distance is between 1,5 and 10 times the diameter of the first lens 319 or the second lens 329.

[0078] Figure 4 illustrates a flowchart of a method, performed by a wireless transceiver node 501, comprising the wireless transceiver 300 and depicted in Figure 5, for joint monostatic radar sensing and data communication. The wireless transceiver node 501 may for example be a network node, such as a base station, or a wireless communications device, such as a User Equipment (UE).

[0079] Action 401

[0080] The method comprises transmitting data signals in the first beam direction BT1. For example, the data communication transmitter and receiver may use one antenna port in each lens, which may be the one with the strongest transmission to or from another wireless transceiver node or communication unit. The other antenna ports are not used for communication, and are hence available for radar operation. According to embodiments herein the operation of the radar sensing may be performed simultaneously as transmitting or receiving the data communication signals or both.

[0081] Action 402

[0082] The method further comprises transmitting and receiving radar signals in a second beam direction BT2-BT4 which differs from the first beam direction BT1 while transmitting the data signals in the first beam direction BT1. Thus, the method may further comprise transmitting and receiving radar signals in the second beam direction BT2-BT4 simultaneously as transmitting the data signals in the first beam direction BT1.

[0083] The wireless transceiver node 501 may transmit the radar signals from two or more second transmitter antenna ports 312-314 in a respective second beam direction BT2- BT4 which differs from the first beam direction BT1 while transmitting data signals in the first beam direction BT 1. The wireless transceiver node 501 may receive the radar signals at two or more second receiver antenna ports 322-324 in the respective second beam direction BT2-BT4 while transmitting the data signals in the first beam direction BT1. The two or more second receiver antenna ports 322-324 used for receiving the radar signals may correspond to the two or more second transmitter antenna ports 312-314 used for transmitting the radar signals such that the receive beams correspond to the transmit beams. For example, the wireless transceiver node 501 may use the second transmitter and receiver antenna ports 312-314, 322-324 sequentially in Tx, Rx pairs (one pair at a time) to search for radar targets in different beam directions using radar signals.

[0084] This is illustrated in Figure 6a where the radar transmitter uses two antenna ports sequentially: ports 3 and 4 until time t2 and ports 2 and 4 after time t2. A top part of Figure 6a illustrates an antenna port utilisation by a data transmitter, e.g. by the first transmitter baseband circuit 312, with respect to time. A lower part of Figure 6a illustrates an antenna port utilisation by a radar transmitter, e.g. by the second transmitter baseband circuit 313, with respect to time. After a certain time t1 there is a data port switch where the data transmitter changes transmitter antenna port from port 1 to port 2. Now the radar transmitter may take advantage of the available transmitter antenna port 1. Therefore at time t2 the radar transmitter changes one of the transmitter antenna ports from port 3 to port 1.

[0085] It is also possible to use more than one Tx, Rx pair at the time to increase the total radar signal power, to improve performance in terms of scanning speed to search all directions, or ability to detect small size targets. This is illustrated in Figure 6b in which the radar signal occupies ports 3 and 4, or 1 and 4 after t2, in parallel.

[0086] Figure 7 illustrates a further embodiment wherein three antenna ports are used for radar transmissions: ports 2, 3 and 4 until time t3 and ports 1, 3 and 4 after time t3. A top part of Figure 7 again illustrates an antenna port utilisation by the data transmitter, e.g. by the first transmitter baseband circuit 312, with respect to time. A lower part of Figure 7 illustrates an antenna port utilisation by the radar transmitter, e.g. by the second transmitter baseband circuit 313, with respect to time. After time t3 there is a data port switch where the data transmitter changes transmitter antenna port from port 1 to port 2. Now the radar transmitter may take advantage of the available transmitter antenna port 1. Therefore at time t3 the radar transmitter changes one of the transmitter antenna ports from port 2 to port 1 , as port 2 is used by the data transmitter after t3.

[0087] The communication may be full duplex (FD) or time division duplex (TDD). In case of TDD there are different options for when to operate the radar.

[0088] If operating the radar in time slots for receiving data communication, when there is no communication transmission, the radar transmitter (baseband 312 and one of the ports 314 - 317) may transmit specialized sensing signals also in the beam direction otherwise occupied by communication. A drawback is that the receiver for data communication must be isolated from the transmitter for radar sensing, much like in full duplex. However, in this type of two-lens setup it is possible to achieve sufficient isolation using vacant antenna elements to pick up the self-interference signal and then cancel it as will be demonstrated below.

[0089] If instead operating the radar in the transmission time slots for data communication, the radar operation will not disturb the receiver for data communication, and no radarinterference cancellation is needed for the receiver for data communication. The receiver for radar sensing, however, may still need some cancellation. A benefit is that the radar may be added to the communication transceiver, without causing any significant interference to the communication, even if multiple-beam radar is used.

[0090] In case of full duplex operation for both communication and radar, interference cancellation for multiple beams may be employed.

[0091] An issue may be radar measurements in the direction of data communication, to avoid a blind spot. The adjacent beam directions are also problematic to avoid disturbances between radar and communication signals. There are different options to solve this problem.

[0092] The communication signal may be re-used also for radar sensing, and transmitted also in adjacent beam directions in different search patterns. A drawback of this option is that the sensing is then performed with a different waveform compared to other directions, and a radar performance may then be different around the communication direction.

[0093] Another alternative, as mentioned above, may be to operate the radar during time slots for receiving data communication, since the transmit antenna port is then available to other signals than for communication. There may also be other time slots when there is no active transmitter for data communication.

[0094] Yet another alternative may be to interrupt the data communication transmission at occasions, so the radar transmission may be performed.

[0095] Action 403

[0096] The wireless transceiver node 501 may receive data signals in the first beam direction BT1 which is equal or approximately equal to beam direction BR1.

[0097] Action 404

[0098] In some embodiments herein the method comprises transmitting and receiving the radar signals in the first beam direction BT1 , BR1 while receiving the data signals in the first beam direction BR1. Thus, the method may further comprise transmitting and receiving radar signals in the second beam direction BT2-BT4 simultaneously as receiving the data signals in the first beam direction BT1. As the radar signals and communication signals will be received from the same direction they need to be separated. One way is to use low enough power in the radar signal so that the radar reflections will not increase the noise floor for the communication signal too much, and then find the radar signal by correlating the received signal with the radar signal.

[0099] Action 405

[0100] In some embodiments disclosed herein the method comprises interrupting transmitting the data signals in the first beam direction BT 1 while transmitting and receiving the radar signals in the first beam direction BT 1 , BR1.

[0101] Action 406

[0102] The method may comprise transmitting and receiving the radar signals in the first beam direction BT1 , BR1 while interrupting transmitting the data signals in the first beam direction BT1.

[0103] Action 407

[0104] In some embodiments the wireless transceiver node 501 transmits the data signals for radar sensing in the first beam direction BT1.

[0105] Action 408

[0106] The wireless transceiver node 501 may transmit and receive the radar signals in the first beam direction BT, BR1.

[0107] When the wireless transceiver node 501 transmits and receives the radar signals in the first beam direction BT 1 , BR1 then the wireless transceiver node 501 may transmit the data signals in a beam direction which differs from the first beam direction BT 1 , such as the second beam direction BT2, BR2, while transmitting and receiving the radar signals in the first beam direction BT1 , BR1. Thus, the roles of "data antenna port" and "radar antenna port" may change. That is, at some point in time, e.g. antenna port 315 may become connected to the first transmitter baseband circuit 312 for transmitting data signals and antenna ports 314, 316 and 317 may be used for radar sensing. More generally, any of the antenna ports 314-317 may be a data port or a radar port. The antenna ports not used for data may be used for radar. Figure 8 schematically illustrates a second wireless transceiver 800 for joint monostatic radar sensing and data communication. The second wireless transceiver 800 is an alternative embodiment to the wireless transceiver 300.

[0108] The second wireless transceiver 800 comprises a wireless data transmitter and receiver 801 . The wireless data transmitter 801 comprises a data transmitter baseband circuit 812 for data signals and a data receiver baseband circuit 813 for data signals. The wireless transmitter 801 further comprises a first switched-beam lens antenna 803. The first switched-beam lens antenna 803 comprises multiple data antenna ports 814- 817. Each of the data antenna ports 814-817 may serve to support data communication.

[0109] The first switched-beam lens antenna 803 further comprises a first lens 819 for beam forming a respective transmit and receive beam from the multiple data antenna ports 814-817.

[0110] The second wireless transceiver 800 further comprises a wireless radar transmitter and receiver 802 comprising a radar transmitter baseband circuit 822 for radar signals and a radar receiver baseband circuit 823 for radar signals.

[0111] The wireless radar transmitter and receiver 802 further comprises a second switched-beam lens antenna 804 comprising multiple radar antenna ports 824-827 and a second lens 829 for beam forming a respective radar beam to the multiple radar antenna ports 824-827. Each of the radar antenna ports 824-827 may serve to support radar sensing.

[0112] A respective data antenna port 814-817 and a respective radar antenna port 824- 827 may comprise a radio-frequency circuit and an antenna element, similar to as depicted in Figure 3b. Further, each of the data antenna ports 814-817 may comprise a first radio-frequency circuit and a first antenna element for transmission and a second radio-frequency circuit and a second antenna element for reception. In another embodiment each of the data antenna ports 814-817 comprises the first radio-frequency circuit for transmission and the second radio-frequency circuit for reception and a common antenna element for both transmission and reception.

[0113] Radar link budget calculation at 300GHz

[0114] A possible drawback with antenna lenses compared to phased arrays is that the total radiated power is less, since operating one power amplifier to generate a beam will provide less output power than an array of power amplifiers. A link budget may be calculated to show that the radar operation may be performed with sufficient performance and range. The frequency is assumed rather high, 300 GHz, to investigate if adequate radar range and speed of targets may be achieved even in that case, and the resulting lens will then be very compact, centimeter sized diameter, for a gain as high as 27dBi used below.

[0115] Assumptions:

[0116] A frequency of communication signals and radar is 300 GHz, so the wavelength is equal to 1 mm.

[0117] Tx has 1 mW output power, i.e. PTX = 0 dBm.

[0118] An integration time of the radar signal, Tint, is equal to 100ps.

[0119] A lens antenna gain, G, at both Tx and Rx is equal to 27dBi.

[0120] A target radar cross section, RCS, is equal to 0.01 m2. The RCS is a measure of how detectable an object is by the radar. A larger RCS indicates that an object is more easily detected. RCS is a property of the target's reflectivity and geometry.

[0121] The receiver noise figure, F, is equal to 20 dB.

[0122] The minimum required Signal-to-Noise Ratio, SNR, for object detection is 10 dB.

[0123] Result:

[0124] A maximum speed of objects is the wavelength / 4 divided by Tint = 2.5 m / s = 9 km / h The minimum input signal at the radar receiver Pmin = 4kT*F*SNR / Tint = - 174+20+10+40 = -104dBm

[0125] A maximum range 13.5 m where both PTX and Pminare in mW.

[0126] A radar operating at 300 GHz with small lenses and an output power of 1 mW and a noise figure of 20 dB may thus be used to detect objects with just 1 dm2of RCS, at distances of 13.5 m moving at speeds up to 9 km / h. This is adequate for many applications, for instance indoors.

[0127] Embodiments herein provide different possibilities for radar-communication coexistence and for providing wide radar direction coverage including the communication direction:

[0128] • Transmit radar in data communication Tx slot, to avoid radar to communication Rx cancellation

[0129] • Interrupt data communication Tx while transmitting radar in the communication direction or neighbor beams • Transmit radar in data communication Rx slot, to allow radar sensing in the communication direction (or neighbor beams) without interrupting communication; may need radar to communication Rx interference cancellation

[0130] • For communication direction (or neighbor beams), data communication signal may be used for sensing to avoid having to transmit a dedicated radar signal there

[0131] Some advantages of embodiments disclosed herein are:

[0132] • Utilizes otherwise unused hardware resources in switched-beam lens antenna communication system for performing radar operations

[0133] • Allows radar sensing also in directions different from the direction of data communication

[0134] • The data communication does not have to be interrupted due to the radar operation

[0135] • Radar sensing may be combined with both TDD and full duplex data communication

[0136] • For TDD data communication, radar may operate in either Rx or Tx slots, or both. Operating in Tx slots results in less interference to communication Rx. Operating in Rx allows radar to transmit dedicated waveform also in the data communication direction.

[0137] Figure 5 also illustrates further optional details of the wireless transceiver node 501. The wireless transceiver node 501 is configured to perform the method actions of Figure 4 above.

[0138] The embodiments herein may be implemented through a processor or one or more processors, such as the processor 504 of a processing circuitry in the transceiver node 501, and depicted in Figure 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 transceiver node 501. 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 transceiver node 501. The transceiver node 501 may further comprise a memory 502 comprising one or more memory units. The memory comprises instructions executable by the processor in the transceiver node 501.

[0139] The respective memory 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 transceiver node 501.

[0140] In some embodiments, a computer program 503 comprises instructions, which when executed by the at least one processor, cause the at least one processor of the transceiver node 501 to perform the actions above.

[0141] In some embodiments, a carrier 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.

[0142] The transceiver node 501 may further comprise an input and output interface, I / O, 506 configured to communicate with other devices. The input and output interface 506 may comprise the wireless transceiver 301 or the second wireless transceiver 800.

[0143] 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).

[0144] Figure 9 illustrates a wireless communications network 170 in which embodiments herein may be implemented.

[0145] The wireless communications network 170 may use a number of different technologies, such as Wi-Fi, Long Term Evolution (LTE), LTE-Advanced, 5G, New Radio (NR), Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications / enhanced Data rate for GSM Evolution (GSM / EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. Embodiments herein relate to recent technology trends that are of particular interest in a 5G context. However, embodiments are also applicable in further development of other existing wireless communication systems such as e.g. WCDMA and LTE and in future wireless communication systems, such as 6G systems.

[0146] Network nodes operate in the wireless communications network 170 such as a network node 511. The network node 511 provides radio coverage over a geographical area, a service area referred to as a cell 15, which may also be referred to as a beam or a beam group of a first radio access technology (RAT), such as 5G, LTE, Wi-Fi or similar. There may be more than one cell. For example, there may be a second cell 16 as well. The network node 511 may be a NR-RAN node, transmission and reception point e.g. a base station, a radio access node such as a Wireless Local Area Network (WLAN) access point or an Access Point Station (AP STA), an access controller, a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNode B), a gNB, a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit capable of communicating with a wireless device within the service area depending e.g. on the radio access technology and terminology used. The respective network node 511 may be referred to as a serving radio access node and communicates with a UE with Downlink (DL) transmissions to the UE and Uplink (UL) transmissions from the UE.

[0147] A number of wireless communications devices operate in the wireless communication network 170, such as a wireless communications device 513.

[0148] The wireless communications device 513 may be a mobile station, a non-access point (non-AP) STA, a STA, a user equipment and / or a wireless terminal, that communicate via one or more Access Networks (AN), e.g. RAN, e.g. via the network node 511 to one or more core networks (CN) e.g. comprising a CN node 13, for example comprising an Access Management Function (AMF). It should be understood by the skilled in the art that “UE” is a non-limiting term which means any terminal, wireless communication terminal, user equipment, Machine Type Communication (MTC) device, Device to Device (D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station communicating within a cell.

[0149] When using the word "comprise" or “comprising” it shall be interpreted as non- limiting, i.e. meaning "consist at least of".

[0150] The embodiments herein are not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used.

Claims

CLAIMS1. A wireless transceiver (300) for joint monostatic radar sensing and data communication, the wireless transceiver (300) comprising: a wireless transmitter (301) comprising: a first transmitter baseband circuit (312) for data signals and a second transmitter baseband circuit (313) for radar signals; and a first switched-beam lens antenna (303) comprising: multiple transmitter antenna ports (314-317); a first lens (319) for beam forming a respective transmit beam from the multiple transmitter antenna ports (314-317); a wireless receiver (302) comprising: a first receiver baseband circuit (322) for data signals and a second receiver baseband circuit (323) for radar signals; a second switched-beam lens antenna (304) comprising: multiple receiver antenna ports (324-327); a second lens (329) for beam forming a respective receive beam to the multiple receiver antenna ports (324-327).

2. The wireless transceiver (300) according to claim 1 , wherein the first transmitter baseband circuit (312) and the second transmitter baseband circuit (313) each are operationally connected to the first switched-beam lens antenna (303), and wherein the first receiver baseband circuit (322) and the second receiver baseband circuit (323) each are operationally connected to the second switched-beam lens antenna (304).

3. The wireless transceiver (300) according to claim 1 or 2, wherein the wireless transmitter (301) is configured to operationally connect the first transmitter baseband circuit (312) to at least a first transmitter antenna port (314) of the multiple transmitter antenna ports (314-317), and wherein the wireless transmitter (301) is configured to operationally connect the second transmitter baseband circuit (313) to at least a second transmitter antenna port (315) of the multiple transmitter antenna ports (314-317), and wherein the wireless receiver (302) is configured to operationally connect the first receiver baseband circuit (322) to at least a first receiver antenna port (324) of the multiple receiver antenna ports (324-327), and wherein the wireless receiver (302) is configured to operationally connect the second receiver basebandcircuit (323) to at least a second receiver antenna port (325) of the multiple receiver antenna ports (324-327).

4. The wireless transceiver (300) according to any of the claims 1-3, wherein at least a first transmitter antenna port (314) of the multiple transmitter antenna ports (314-317) is operationally connected to the first transmitter baseband circuit (312) and at least a second antenna port (315) of the multiple transmitter antenna ports (314-317) is operationally connected to the second transmitter baseband circuit (313); wherein at least a first receiver antenna port (324) of the multiple receiver antenna ports (324- 327) is operationally connected to the first receiver baseband circuit (322) and at least a second receiver antenna port (325) of the multiple receiver antenna ports (324-327) is operationally connected to the second receiver baseband circuit (323).

5. The wireless transceiver (300) according to any of the claims 1-4, wherein the multiple transmitter antenna ports (314-317) comprise further second transmitter antenna ports (316-317) and wherein the second transmitter baseband circuit (313) is configured to be sequentially operationally connected to the second transmitter antenna ports (315-317), and wherein the multiple receiver antenna ports (324-327) comprise further second receiver antenna ports (326-327) and wherein the second receiver baseband circuit (323) is configured to be sequentially operationally connected to the second receiver antenna ports (325-327).

6. The wireless transceiver (300) according to any of the claims 1-5, wherein the wireless transmitter (301) is configured to transmit and receive the data signals in a first beam direction (BT1) and to transmit and receive the radar signals in a second beam direction (BT2-BT4) which differs from the first beam direction (BT1), and wherein the wireless transmitter (301) is configured to transmit the radar signals while it transmits the data signals.

7. The wireless transceiver (300) according to claim 6, wherein the wireless transmitter (301) is further configured to transmit the radar signals in the first beam direction (BT1), and wherein the wireless transmitter (301) is configured to interrupt the transmission of the data signals while it transmits the radar signals in the first beam direction (BT1).

8. The wireless transceiver (300) according to claim 7, wherein the wireless transmitter (301) is further configured to transmit the radar signals in the first beam direction (BT1) while the wireless transceiver (300) receives the data signals in the first beam direction (BT1).

9. The wireless transceiver (300) according to claim 7, wherein the wireless transmitter (301) is further configured to use the data signals for radar sensing in the first beam direction (BT1).

10. The wireless transceiver (300) according to claim 7, wherein the second lens (329) is arranged such that an axis of the second lens (329) is at a distance from an axis of the first lens (319) by at least one diameter of the first lens (319) or the second lens (329), preferably the distance is between 1,5 and 10 times the diameter of the first lens (319) or the second lens (329).

11. The wireless transceiver (300) according to any of the claims 1-10, wherein a respective transmitter antenna port (314-317) and a respective receiver antenna port (324-327) comprises a radio-frequency circuit (331, 332) and an antenna element (341 , 342).

12. A wireless transceiver node (300) comprising the wireless transceiver (300) according to any of the claims 1-11.

13. A method, performed by a wireless transceiver node (501) for joint monostatic radar sensing and data communication, the wireless transceiver node (501) comprising a wireless transceiver (300) comprising: a wireless transmitter (301) comprising: a first transmitter baseband circuit (312) for data signals and a second transmitter baseband circuit (313) for radar signals; and a first switched-beam lens antenna (303) comprising: multiple transmitter antenna ports (314-317); and a first lens (319) for steering a respective transmit beam from the multiple transmitter antenna ports (314-317); a wireless receiver (302) comprising: a first receiver baseband circuit (322) for data signals and a second receiver baseband circuit (323) for radar signals;a second switched-beam lens antenna (304) comprising: multiple receiver antenna ports (324-327); and a second lens (329) for steering a respective receive beam to the multiple receiver antenna ports (324-327); the method comprising: transmitting (401) data signals in a first beam direction (BT1); and transmitting and receiving (402) radar signals in a second beam direction (BT2-BT4) which differs from the first beam direction (BT 1) while transmitting the data signals in the first beam direction (BT1).

14. The method according to claim 13, further comprising transmitting and receiving (406) the radar signals in the first beam direction (BT1), and interrupting (405) transmitting the data signals in the first beam direction (BT1) while transmitting and receiving the radar signals in the first beam direction (BT1).

15. The method according to claim 13, further comprising transmitting and receiving (404) the radar signals in the first beam direction (BT 1) while receiving the data signals in the first beam direction (BT1).

16. The method according to claim 13, further comprising transmitting (407) the data signals for radar sensing in the first beam direction (BT1).

17. The method according to claim any of the claims 13-14, further comprising transmitting (408) the data signals in a beam direction which differs from the first beam direction (BT1) while transmitting and receiving the radar signals in the first beam direction (BT1).

18. The method according to any of the claims 13-17, transmitting (402) the radar signals from two or more second transmitter antenna ports (312-314) in a respective second beam direction (BT2-BT4) which differs from the first beam direction (BT1) while transmitting (401) data signals in the first beam direction (BT1), and receiving (402) the radar signals at two or more second receiver antenna ports (322-324) in the respective second beam direction (BT2-BT4) while transmitting (401) the data signals in the first beam direction (BT1).

19. A computer program (703), comprising computer readable code units which when executed on a computer causes the computer to perform the method according to any one of claims 13-18.

20. A carrier (705) comprising the computer program according to the preceding claim, wherein the carrier (705) is one of an electronic signal, an optical signal, a radio signal and a computer readable medium.