Coordination of wireless communication units and radar units in a wireless communication network

Abstract

A device (100) and a method therein for coordinating the operation of a radar unit (110) and a wireless communication unit (120) included in the device (100) are disclosed. The device (100) and the method enable the radar unit (110) to detect interference and thereby mitigate interference or reduce the risk of being interfered with and causing interference. The radar unit (110) obtains information about interference conditions within a frequency range corresponding to a frequency range used for radar pulse transmission. The information about the interference conditions may be obtained from the wireless communication unit (120) included in the device (100) or determined by the radar unit itself, for example using a listen-before-talk process. By making the radar unit (110) aware of the communication of the wireless communication unit (120), the radar unit (110) may determine when to perform radar transmissions for measurement. In this way, the risk of interference between the wireless communication unit (120) and the radar unit (110) is reduced. Further, taking the interference conditions into account when determining the measurement result improves the accuracy of the measurement, thereby achieving more reliable radar measurements. By modifying any one of the signal strength, transmission direction and frequency range of the radar pulse based on the obtained interference situation, interference from the radar unit (110) to another communication unit (120) can be reduced and the measurement accuracy can be further improved. In addition, the communication performance of the wireless communication unit (120) can be improved because the radar unit will not transmit when the wireless communication unit (120) is active. Individual measurement results (such as distance) can be weighted differently by factors depending on the RSSI level. The device (100) can be any kind of device including a radar sensor and a wireless communication unit, such as a vehicle, a smart phone, a modem, a laptop, a tablet computer, a wearable device, an Internet of Things (IoT) device, an electronic health device (such as a wireless heart or respiratory monitor), etc.

Description

Technical Field

[0001] Embodiments herein relate to a device and a method therein. In particular, they relate to how to coordinate the operation of a wireless communication unit and a radar unit included in a device in a wireless communication network. Background Art

[0002] Low power, low cost radar sensors have been developed and can be used in a number of new devices, such as in cars for parking assistance, in autonomous lawn mowers or vacuum cleaners to detect living things in front of the lawn mower or vacuum cleaner, etc. Typically, the 61 GHz Industrial, Scientific and Medical (ISM) band is used for such radar applications and allows highly accurate distance measurements up to tens of meters.

[0003] Mobile devices such as smartphones are examples of devices that include multiple sensors, such as cameras, microphones, radio antennas, and global positioning system (GPS) receivers. Future smartphones or mobile devices may additionally be equipped with, for example, a radar sensor, allowing accurate measurements over short distances of up to a few meters. Such a radar sensor may or may not be combined with a communication unit so that the unit can be used for wireless communication and radar applications, since both may operate in the same frequency range and include similar building blocks. Therefore, smart mobile phones make for an interesting platform for sensor fusion applications.

[0004] In a device that includes both a wireless communication unit (WRU) and a radar unit, the wireless communication unit and the radar unit may interfere with each other if they are transmitting and receiving at the same time. This may distort the distance measurements made by the radar unit and the communication attempts made by the WRU. Summary of the invention

[0005] It is therefore an object of embodiments herein to provide an apparatus and method therein for coordinating the operation of a wireless communication unit and a radar unit.

[0006] According to one aspect of the embodiments herein, the purpose is achieved by a device comprising: at least one radar unit configured to send radar pulses over a first frequency range; and a wireless communication unit configured to operate over a second frequency range. At least one radar unit comprises a radar transceiver and a radar signal processing unit. The radar unit is configured to obtain information about an interference situation over the first frequency range. If the interference situation satisfies a condition, the radar unit is configured to send at least one radar pulse based on the obtained interference situation, and receive at least one radar pulse response associated with a reflection of at least one sent radar pulse. The radar unit is also configured to determine at least one measurement result based on the sent and received radar pulses.

[0007] According to one aspect of the embodiments herein, the object is achieved by a method performed in a device, the device comprising: at least one radar unit configured to send radar pulses on a first frequency range; and a wireless communication unit configured to operate on a second frequency range. At least one radar unit comprises a radar transceiver and a radar signal processing unit. The radar unit obtains information about an interference situation on the first frequency range. If the interference situation satisfies a condition, the radar unit sends at least one radar pulse based on the obtained interference situation, and receives at least one radar pulse response associated with a reflection of at least one sent radar pulse. The radar unit determines at least one measurement result based on the sent and received radar pulses.

[0008] The device and the method therein according to the embodiments herein enable a radar unit to detect interference and thereby mitigate interference or reduce the risk of being exposed to and causing interference. The radar unit obtains information about interference conditions within a frequency range corresponding to the frequency range used for radar pulse transmission. Information about the interference conditions can be obtained from a wireless communication unit in the device or determined by the radar unit, for example, using a listen-before-talk process. By making the radar unit aware of the communication of the wireless communication unit, the radar unit can determine when to perform radar transmissions for measurement. In this way, the risk of interference between the wireless communication unit and the radar unit is reduced. Further, taking the interference conditions into account when determining the measurement results improves the accuracy of the measurement, thereby achieving more reliable radar measurements.

[0009] Accordingly, embodiments herein provide apparatus and methods therein for coordinating the operation of a wireless communication unit and a radar unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Examples of embodiments herein are described in more detail with reference to the accompanying drawings, in which:

[0011] Figure 1 is a schematic block diagram illustrating an apparatus according to embodiments herein; and

[0012] Figure 2 is a flow chart illustrating a method performed in a device according to embodiments herein. DETAILED DESCRIPTION

[0013] Figure 1A block diagram of a device or apparatus 100 according to an embodiment herein is depicted. The device 100 includes at least one radar unit 110, a wireless communication unit (WRU) 120, and a control unit 130. The control unit 130 enables communication between the radar unit 110 and the WRU 120. The WRU 120 includes a transceiver Tx / Rx 122 and a processing unit 124, which processes received and transmitted signals. The radar unit 110 also includes a transceiver Tx / Rx 112 and a processing unit 114, which processes transmitted and received radar pulses to obtain measurements. The device 100 may be any kind of device including both a radar sensor and a wireless communication unit, such as a vehicle, a smartphone, a modem, a laptop, a tablet, a wearable device, an Internet of Things (IoT) device, an electronic health device (such as a wireless heart or respiratory monitor, etc.).

[0014] The radar unit 110 is configured to transmit radar pulses over a first frequency range. The WRU 120 is configured to operate over a second frequency range. In some embodiments, the second frequency range may partially overlap with the first frequency range, while in other embodiments, it will not overlap. The first frequency range may be a frequency band or a group of frequency bands, a system bandwidth or a bandwidth portion (i.e., a portion of the system bandwidth). For example, the first frequency range may be any one of the ISM bands such as 2.5 GHz, 6 GHz, 5 GHz, 24 GHz, 61 GHz.

[0015] According to embodiments herein, in order to coordinate the operations of radar unit 110 and WRU 120 in device 100 , radar unit 110 is configured to obtain information about interference conditions on a first frequency range.

[0016] The information about the interference situation may be obtained in a variety of ways. According to some embodiments herein, the radar unit 110 may receive the information about the interference situation from the WRU 120 via, for example, the control unit 130 .

[0017] The WRU 120 may use a listen before talk (LBT) process to determine possible interference. In the LBT process, the WRU 120 may measure interference conditions during a configured or predefined time period in at least a subset or portion of the first frequency range. The interference conditions are typically measured as a received signal strength level and represented by a received signal strength indication (RSSI) parameter. The RSSI may typically be compared to a threshold. An RSSI above the threshold may imply ongoing transmission and reception in the WRU 120, and therefore, radar pulses should not be sent. This is because if the WRU 120 is receiving data packets from elsewhere and suddenly a radar pulse is sent, it is likely that the data packets will be lost. The RSSI information may be sent to the radar unit 110 via the control unit 130.

[0018] In another embodiment, the interference situation on the first frequency range is determined based on currently ongoing transmissions in the second frequency range in the WRU 120. In the case where the second frequency range does not at least partially overlap with the first frequency range, the interference situation in the first frequency range may be determined based on an estimation or mathematical modeling of possible harmonics, intermodulation products, spurious emissions that may be generated in the first frequency range due to nonlinearities in the transmitter of the WRU 120. The determination of interference from the second frequency range to the first frequency range may be performed by the WRU 120, the control unit 130, or the radar unit 110.

[0019] The interference situation may be determined, for example, based on received signal strength in at least a portion or subset of the first frequency range.In one embodiment, the direction of the received signal may be used when evaluating the LBT so that the LBT is focused in the direction in which radar measurements will occur.

[0020] Alternatively, direction information may be included in the information used to determine the interference situation.

[0021] Therefore, according to some embodiments herein, radar unit 110 may be configured to perform an LBT process in the first frequency range or in at least a subset of the frequency range to obtain information about interference conditions on the first frequency range. The LBT process may be performed in the direction in which the radar measurement occurs.

[0022] The radar unit 110 is then configured to determine whether the interference situation satisfies a condition, for example by means of the configured processing unit 114. The condition may be a pre-configured or determined criterion or requirement, such as "Is the interference level below..." or "Is a communication activity ongoing?" The condition may be determined based on LBT-related requirements for the first frequency range. For example, the radar unit performs LBT to check whether there is ongoing communication activity in the first frequency range. In other embodiments, the condition may be determined based on the receiver performance of the radar unit, such as the sensitivity level of its receiver. For example, if the sensitivity level of the radar receiver is high, the allowed interference level should be lower.

[0023] If the interference situation satisfies the condition, radar unit 110 is further configured (eg by means of transceiver Tx / Rx 112) to send at least one radar pulse based on the obtained interference situation. The at least one radar pulse may be sent without any modification.

[0024] In some embodiments, at least one radar pulse can be modified based on the interference situation obtained. For example, if a frequency range in the first frequency range or a subset of the first frequency range is interfered, the radar pulse can be modified so that no energy or reduced energy is emitted in the interfered frequency range. This can be performed by some filtering of the radar pulse. For example, if a radar pulse based on a fast Fourier transform (FFT) is used, the subcarrier corresponding to the interfered frequency range can be empty, and the corresponding energy can be applied to the uninterrupted frequency range. If the radar pulse is a pulse with particularly good correlation characteristics, such as a Chirp signal Zadoff-Chu sequence, an m sequence, or a Gold sequence, these pulses can be punctured or filtered out in the interfered frequency range, or two separate pulse sequences can be formed so that one sequence is used below the interfered frequency range and the other sequence is used above the interfered frequency range. Alternatively, only one of the frequency ranges below the interfered frequency range or the frequency range above the interfered frequency range can be used, usually the largest one. Then, corresponding modifications can be made in the radar receiver.

[0025] Therefore, according to some embodiments herein, when a frequency range within a first frequency range is interfered, at least one radar pulse may be modified so that two separate pulse sequences are formed, one pulse sequence used below the interfered frequency range and another pulse sequence used above the interfered frequency range. The radar pulse may be modified so that only one of the frequency range below the interfered frequency range or the frequency range above the interfered frequency range is used.

[0026] According to some embodiments herein, at least one radar pulse may be modified based on a received interference level such that a signal strength of the radar pulse is below a certain power level.

[0027] According to some embodiments herein, at least one radar pulse may be modified based on the direction of the received interference such that the radar pulse is sent in a specific direction.

[0028] In some embodiments, the transmission of the radar pulse may be shorter than or as long as the LBT process allows the transmission, i.e., how long the radar transmission is allowed to be for a given LBT process is defined by a standard predefined rule for the first frequency range. The dwell time depends on which ISM band is used. For example, the 24 GHz band has 4 μs every 3 ms. Radar unit 110 may be configured to perform other radar transmissions within the effective transmission duration determined based on at least a subset of the first frequency range.

[0029] Radar unit 110 is also configured to receive at least one radar pulse response associated with a reflection of at least one transmitted radar pulse and to determine at least one measurement result based on the transmitted and received radar pulses.

[0030] According to some embodiments herein, the measurement results may be adapted, adjusted or manipulated based on the interference situation obtained. For example, the measurement results may be adjusted by a scaling factor or a bias factor to account for possible interference from another transmission unit (such as WRU 120). The scaling factor or bias factor may be included in the measurement results themselves or in the variance estimate of the measurement. The scaling factor or bias factor may be a function of any of the following:

[0031] a. an interference level in at least a portion of the first frequency range;

[0032] b. a power spectral density distribution of interference in at least a portion of the first frequency range;

[0033] c. The direction of the interference.

[0034] One way to adapt the measurement results may be to scale based on the RSSI level. For example, if some pulses are more interfered than others, then when taking a certain average over the measurements, the measurement samples may be scaled by a factor a=0.5 for pulses that are interfered with more than a threshold, otherwise a scaling factor a=1 is set.

[0035] For example, assuming the received signal is r i =s i +n i , where s i is the received signal, n iis the noise, and if the measurements are averaged, then in, Thus, it can be seen that the bias factor can be set to be proportional to the RSSI. Thus, when averaging the measurements, one approach could be to set the bias factor to approximately 0 if the RSSI is less than a threshold, and to set the bias factor to the RSSI otherwise.

[0036] Therefore, according to some embodiments herein, individual measurements (eg, distances) may be weighted differently with factors that depend on the RSSI level.

[0037] Now refer to Figure 2 An example of an embodiment of a method performed in the device 100 for coordinating the operations of the radar unit 110 and the WRU 120 included in the device 100 is described. The method comprises the following actions.

[0038] Action 210

[0039] Radar unit 110 receives information about interference situations in a first frequency range.

[0040] According to some embodiments herein, the radar unit 110 is configured to receive information about interference situations from the wireless communication unit 120 .

[0041] The interference situation on the first frequency range may be determined based on transmissions performed in the second frequency range by the wireless communication unit 120. The interference situation on the first frequency range may be determined based on estimates or mathematical modeling of harmonics, intermodulation products, spurious emissions generated in the first frequency range due to nonlinearities in the transmitter of the wireless communication unit transmitting the signal in the second frequency range.

[0042] The interference situation in the first frequency range can be determined based on information about the direction in which the radar measurement takes place.

[0043] The interference situation in the first frequency range may be determined based on the direction information in which the wireless communication unit 120 transmission occurs.

[0044] According to some embodiments herein, radar unit 110 performs an LBT process in at least a portion of the first frequency range to obtain information about interference conditions over the first frequency range. The LBT process may be performed in a direction in which radar measurements occur.

[0045] The interference situation may be determined based on received signal strengths within at least a subset of the first frequency range.

[0046] Action 220

[0047] If the interference situation satisfies the condition, radar unit 110 transmits at least one radar pulse based on the obtained interference situation.

[0048] The condition may be determined based on listen-before-talk (LBT) related requirements for the first frequency range.

[0049] The condition may be determined based on the reception performance of the radar sensor unit.

[0050] At least one radar pulse may be modified based on the obtained interference situation, as described below:

[0051] When a frequency range within the first frequency range is interfered, the radar pulses may be modified such that no energy or reduced energy is transmitted in the interfered frequency range.

[0052] When a frequency range within the first frequency range is interfered, the radar pulses may be modified such that two separate pulse trains are formed, one pulse train for use below the interfered frequency range and another pulse train for use above the interfered frequency range.

[0053] When a frequency range within the first frequency range is interfered, the radar pulse may be modified such that only one of a frequency range below the interfered frequency range or a frequency range above the interfered frequency range is used.

[0054] At least one radar pulse may be modified such that a signal strength of the radar pulse is below a certain power level.

[0055] At least one radar pulse may be modified such that the radar pulse is transmitted in a particular direction.

[0056] Action 230

[0057] Radar unit 110 receives at least one radar pulse response associated with a reflection of at least one transmitted radar pulse.

[0058] Action 240

[0059] Radar unit 110 determines at least one measurement result based on the transmitted and received radar pulses and taking into account interference situations.

[0060] According to some embodiments herein, the radar unit 110 may also perform the following actions.

[0061] Action 250

[0062] Radar unit 110 may adjust the measurement result based on the obtained interference situation. The measurement result may be adjusted by a scaling factor or a bias factor.

[0063] In short, the device 100 and the method therein according to the embodiments herein enable the radar unit 110 to detect interference and thereby mitigate interference or reduce the risk of being interfered with and causing interference. The radar unit 110 obtains information about interference conditions in a frequency range corresponding to the frequency range used for radar pulse transmission. The information about the interference conditions can be obtained from the wireless communication unit 120 included in the device 100 or determined by the radar unit itself, for example, using a listen-before-talk process. By making the radar unit 110 aware of the communication of the wireless communication unit 120, the radar unit 110 can determine when to perform radar transmission for measurement. In this way, the risk of interference between the wireless communication unit 120 and the radar unit 110 is reduced. Further, considering the interference conditions when determining the measurement results improves the accuracy of the measurement, thereby achieving more reliable radar measurements. By modifying any one of the signal strength, transmission direction and frequency range of the radar pulse based on the obtained interference conditions, the interference from the radar unit 110 to another communication unit 120 can be reduced, and the measurement accuracy can be further improved. In addition, the communication performance of the wireless communication unit 120 can be improved because the radar unit will not transmit when the wireless communication unit 120 is active.

[0064] Those skilled in the art will appreciate that the control unit 130, the processing unit 114, and the processing unit 124 in the communication unit 124 described above in the device 100 may be referred to as a circuit / unit, a combination of analog circuits and digital circuits, one or more processors configured with software and / or firmware, and / or any other digital hardware that performs the functions of each circuit / unit. The device 100 may include other circuits / units, such as one or more memory units 140, and may be arranged to store received information, measurements, data, configurations, and applications to perform the methods herein when executed in the device 100.

[0065] The embodiments for coordinating the operations of radar unit 110 and communication unit 120 herein may be implemented by one or more processors (such as processing units 114, 124 or control unit 130 in device 100) 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 example, using Figure 1 The form of a data carrier 150 shown carrying a computer program code 152 for executing the embodiments herein when loaded into the device 100. One such carrier may be in the form of a CD ROM disc. However, it is also feasible for other data carriers (such as a memory stick). In addition, the computer program code may be provided as pure program code on a server or cloud and downloaded to the device 100.

[0066] When the word "include" or "comprising" is used, it should be interpreted as non-limiting, ie meaning "includes at least".

[0067] The embodiments herein are not limited to the preferred embodiments described above. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be considered as limiting the scope of the invention as defined by the appended claims.

Claims

1. A device (100) configured for use in a wireless communication network, comprising: at least one radar unit (110) configured to transmit radar pulses over a first frequency range; and a wireless communication unit (120) configured to operate over a second frequency range, wherein the at least one radar unit (110) comprises a radar transceiver (112) and a radar signal processing unit (114), and is configured to: obtaining information about interference conditions in the first frequency range; Coordinating the operation of the radar unit (110) and the wireless communication unit (120) by adjusting a measurement result based on an obtained interference situation and / or modifying at least one radar pulse based on an obtained interference situation, comprising: If the interference condition is met, then: Based on the obtained interference situation, sending at least one radar pulse; receiving at least one radar pulse response associated with a reflection of the at least one transmitted radar pulse; and At least one measurement result is determined based on the transmitted radar pulse and the received radar pulse response.

2. The device (100) according to claim 1, wherein The measurement results are adjusted by a scaling factor or an offset factor.

3. The device (100) according to claim 2, wherein: The scaling factor or bias factor is a function of any of: a) an interference level in at least a portion of said first frequency range; b) a power spectral density distribution of interference in at least a portion of said first frequency range; c) Direction of interference.

4. The device (100) according to any one of claims 1 to 3, wherein: The condition is determined based on listen-before-talk (LBT) related requirements for the first frequency range.

5. The device (100) according to any one of claims 1 to 3, wherein: The condition is determined based on receiver performance of the radar unit.

6. The device (100) according to any one of claims 1 to 3, wherein: The radar unit (110) is configured to receive information about the interference situation from the wireless communication unit.

7. The device (100) according to claim 6, wherein An interference situation in the first frequency range is determined based on transmissions performed by the wireless communication unit in a second frequency range.

8. The device (100) according to any one of claims 1 to 3, wherein: The interference situation on the first frequency range is determined based on estimation or mathematical modeling of harmonics, intermodulation products, spurious emissions generated in the first frequency range due to nonlinearities in a transmitter of the wireless communication unit transmitting signals in the second frequency range.

9. The device (100) according to any one of claims 1 to 3, wherein: The interference situation in the first frequency range is determined based on information about the direction in which the radar measurements take place.

10. The device (100) according to any one of claims 1 to 3, wherein: Interference conditions in the first frequency range are determined based on information about a direction in which transmissions by the wireless communication unit occur.

11. The device (100) according to any one of claims 1 to 3, wherein: The second frequency range at least partially overlaps with the first frequency range.

12. The device (100) according to any one of claims 1 to 3, wherein: The radar unit is configured to perform an LBT procedure in at least a portion of the first frequency range to obtain information about interference conditions over the first frequency range.

13. The device (100) according to claim 12, wherein The LBT process is performed in the direction in which the radar measurements take place.

14. The device (100) according to claim 12, wherein: The radar unit is configured to perform other radar transmissions during an effective transmission duration determined based on at least a subset of the first frequency range.

15. The device (100) according to any one of claims 1 to 3, wherein: The interference condition is determined based on received signal strength within at least a subset of the first frequency range.

16. The device (100) according to claim 1, wherein When a frequency range within the first frequency range is interfered, the at least one radar pulse is modified such that no energy or reduced energy is emitted in the interfered frequency range.

17. The device (100) according to claim 1, wherein When a frequency range within the first frequency range is interfered, the radar pulses are modified such that two separate pulse trains are formed, one pulse train being used below the interfered frequency range and another pulse train being used above the interfered frequency range.

18. The device (100) according to claim 1, wherein When a frequency range within the first frequency range is interfered, the at least one radar pulse is modified such that only one of a frequency range below the interfered frequency range or a frequency range above the interfered frequency range is used.

19. The apparatus according to claim 1, wherein: The at least one radar pulse is modified based on a received interference level.

20. The apparatus of claim 1, wherein: The at least one radar pulse is modified based on the direction of the received interference.

21. The apparatus according to any one of claims 1 to 3, wherein: The first frequency range is the 61 GHz Industrial, Scientific and Medical (ISM) band.

22. A method performed in a device (100) configured for use in a wireless communication network, for coordinating the operation of a radar unit (110) and a wireless communication unit (120) included in the device (100), wherein: The radar unit (110) is configured to transmit radar pulses over a first frequency range, the wireless communication unit (120) is configured to operate over a second frequency range, the method comprising: Obtaining (210) information for the radar unit (110) about interference conditions in the first frequency range; Coordinating the operation of the radar unit (110) and the wireless communication unit (120) by adjusting a measurement result based on an obtained interference situation and / or modifying at least one radar pulse based on an obtained interference situation, comprising: If the interference condition meets the condition, then The radar unit (110) transmits (220) at least one radar pulse based on the interference situation obtained; receiving (230), by the radar unit (110), at least one radar pulse response associated with a reflection of the at least one transmitted radar pulse; and At least one measurement result is determined (240) based on the transmitted radar pulse and the received radar pulse response.

23. The method according to claim 22, wherein: The condition is determined based on a listen-before-talk (LBT) related requirement for the first frequency range or based on a receiver performance of the radar unit.

24. The method according to any one of claims 22 to 23, wherein: An interference situation in the first frequency range is determined based on transmissions performed by the wireless communication unit in a second frequency range.

25. The method according to any one of claims 22 to 23, wherein: The interference situation in the first frequency range is determined based on information about the direction in which the radar measurements take place.

26. The method according to any one of claims 22 to 23, wherein: Interference conditions in the first frequency range are determined based on information about a direction in which transmissions by the wireless communication unit occur.

27. The method according to any one of claims 22 to 23, wherein: The radar unit is configured to perform an LBT procedure in at least a portion of the first frequency range to obtain information about interference conditions over the first frequency range.

28. The method according to claim 27, wherein: The LBT process is performed in the direction in which the radar measurements take place.

29. The method according to any one of claims 22 to 23, wherein: The interference condition is determined based on received signal strength within at least a subset of the first frequency range.

Images