Apparatus with steering and channel stitching to extend bandwidth

Abstract

Described herein is an RF device (100) comprising: i) a first channel (121) having a first frequency band, configured to receive a first signal; ii) a second channel (122) having a second frequency band configured to receive a second signal, where the first frequency band is different from the second frequency band; and iii) a control device (110), the control device (110) being configured to: a) obtain a first channel response associated with a received first signal at the first channel (121); b) obtaining a second channel response associated with a received second signal at the second channel (122); c) calibrating (111) the first channel response and the second channel response by steering (114) to a calibration basis (130); and d) combining the calibrated first channel response with the second channel response by channel stitching (112) to obtain a combined channel response (115).

Description

Technical Field

[0001] The present disclosure relates to a radio frequency (RF) device having at least two channels, each channel being used for a different bandwidth (frequency range). In particular, the device comprises a control device configured to calibrate a signal received from a first channel and a further signal received from a second channel, in particular by turning to a calibration basis and then combining the signals by channel splicing. The present disclosure further relates to a method of operating such a device. Therefore, the present disclosure may relate to the technical field of RF devices, in particular, the technical field of ultra-wideband (UWB) radar applications. Background Art

[0002] Radio frequency (RF) signals / waves are used for communication and to determine spatial properties such as position, distance, angle or velocity of a target (object or person or vehicle of interest). For example, in radar applications, a transmitter transmits an RF signal towards a target, and one or more receivers obtain reflections (echoes) of the RF signal that have been reflected by the target. For example, ultra-wideband (UWB) wireless technology enables safe and accurate ranging with an accuracy of less than 5 cm, and can also be used as a radar device for receiving reflected signals from a target. For example, a UWB device can be used as a pulse radar, in which a short duration pulse is transmitted and a reflection of the short duration pulse is received. This reflection is captured as a change in the channel impulse response (CIR) measured by the receiver. However, the performance of the RF device / system may generally be limited by bandwidth, such as in the case of a UWB radar system, to a range of 0.5 to 1 GHz (for a standardized IEEE channel).

[0003] Figure 8 The channel response from a conventional radar device (here a pulsed UWB device) is shown. The y-axis shows the amplitude and the x-axis shows the path length (of the radar signal) in meters. Channel impulse response measurements using UWB pulses typically exhibit high temporal resolution and the measured peaks can estimate the range, e.g., to one or more targets and / or surfaces. In the current example, three main peaks can be identified: o , d1 and d2 (multi-tap channels). The accuracy and resolution of the peak position is related to the steepness of the corresponding slope (i.e., the pulse width). As a benchmark for accuracy estimation, the Cramér-Rao lower bound can be applied, whereby higher bandwidths can reduce variations.

[0004] In many applications (e.g. UWB), the bandwidth is still limited, for example, by the standards applied. In the current example, a standardized UWB bandwidth of B=500 MHz for a single channel 121 has been applied. In the current example, it can be seen that for a bandwidth of 500 MHz, the resolution and accuracy may not be satisfactory. One would like to use the maximum bandwidth possible, however, this may be limited by hardware and standardization. Summary of the invention

[0005] It may be desirable to provide an RF device with extended bandwidth in an efficient and reliable manner. An RF device, a method, and a method of use are provided.

[0006] According to one aspect of the present disclosure, an RF device (e.g., a radar device, in particular, a UWB device) is described, the RF device comprising:

[0007] i) a first channel (e.g., channel 5 of the UWB standard) having a first frequency band (e.g., having a center frequency at 6.5 GHz), the first channel being configured to receive a (RF) first signal (e.g., a first reflection of a first radar signal from a transmitter);

[0008] ii) a second channel (e.g., channel 9 of the UWB standard; specifically, adjacent or non-adjacent to the first channel) having a second frequency band (e.g., having a center frequency at 8 GHz), the second channel being configured to receive a (RF) second signal (e.g., a second reflection of a second radar signal from the transmitter) (the first signal and the second signal may be similar or different), wherein the first frequency band is different from the second frequency band (overlapping or non-overlapping); and

[0009] iii) a control device (e.g., a processor, a chip, an integrated circuit, etc.), the control device being configured to:

[0010] a) obtaining a first channel response (specifically, a first channel impulse response and / or a first spectrum) associated with a received first signal at a first channel;

[0011] b) obtaining a second channel response (specifically, a second channel impulse response and / or a second spectrum) associated with the received second signal at the second channel;

[0012] c) calibrating (aligning, making coherent) the first channel response with the second channel response by steering (the first channel response and / or the second channel response) to a calibration basis (specifically, dominant peaks / taps / phases / positions; specifically, present in the first channel response and the second channel response); and

[0013] d) combining the (calibrated) first channel response with the second channel response by channel splicing (frequency band splicing, specifically, subsequent coherent combining) to obtain a combined channel response (combined spectrum).

[0014] According to another aspect of the present disclosure, a method of operating an RF device (e.g., as described above) is described, the method comprising:

[0015] i) obtaining a first channel response associated with a received first signal at a first channel having a first frequency band;

[0016] ii) obtaining a second channel response associated with a received second signal at a second channel having a second frequency band,

[0017] wherein the first frequency band is different from the second frequency band;

[0018] iii) calibrating the first channel response and the second channel response by turning to a calibration basis; and

[0019] iv) combining the (calibrated) first channel response with the second channel response to obtain a combined channel response, wherein the combining comprises channel concatenation.

[0020] According to another aspect of the present disclosure, a use (method of use) is described which uses a steering to calibration basis to calibrate (align) channels having non-adjacent frequency bands with channel stitching.

[0021] In the present context, the term "channel stitching" (or frequency band stitching or spectrum stitching) may specifically refer to the process of combining multiple passband signals. Preferably, the stitching may comprise a subsequent and coherent combination of channel impulse responses with different frequency bands.

[0022] According to exemplary embodiments, the present disclosure may be based on the idea that an RF device with extended bandwidth may be provided in an efficient and reliable manner when the bandwidth is increased by channel-splicing the channel responses of two or more (adjacent or non-adjacent) channels of the device, and when the channel responses of the channels are aligned relative to a calibration basis. The calibration basis may, for example, be a main peak and / or a target peak present in all channel responses to be combined. A turn may be made towards the calibration basis to obtain coherence of the channels to be combined (specifically, at the calibration basis region). In this way, the bandwidth may be significantly increased (e.g., four times) while the accuracy / resolution may be greatly increased, see e.g. Figure 8 Furthermore, even non-adjacent channel responses can be efficiently spliced ​​in the described manner.

[0023] The aspects defined above and further aspects of the disclosure will be apparent from the examples of embodiment described hereinafter and are explained with reference to these examples of embodiment.The disclosure will be described in more detail hereinafter with reference to examples of embodiment but to which the disclosure is not limited.

[0024] Exemplary Embodiments

[0025] According to an embodiment, the first frequency band and the second frequency band are adjacent to each other (adjacent). Specifically, there may be no other frequency bands (or channels) in between. In an embodiment, the first channel and the second channel are adjacent channels, for example, channel 5 and channel 6 of the IEEE standard (e.g., IEEE 802.15.4-2020, specifically, chapter 15.4.1). In an example, the other bandwidths of the other channels may also be adjacent. Thus, particularly efficient channel splicing can be achieved using existing architectures.

[0026] According to one embodiment, the first frequency band and the second frequency band are not adjacent to each other. Specifically, there may be another frequency band (or channel) in between. In one embodiment, the first channel and the second channel are non-adjacent channels, for example, channel 5 and channel 9 of the IEEE standard. In one example, the additional bandwidth of the additional channel may also be adjacent to or not adjacent to the first channel and / or the second channel. Thus, even in the case where the channels are not adjacent, particularly efficient channel splicing can be achieved using existing architectures.

[0027] According to an embodiment, there is a frequency gap between the first frequency band and the second frequency band. As described above, the first frequency band and the second frequency band may not be adjacent. In this case, there will be a gap between the two frequency bands. For example, the first frequency band may be 500 MHz, centered at 6.5 GHz, and the second frequency band may also be 500 MHz, centered at 8 GHz. Thus, a gap of 500 MHz will exist therebetween.

[0028] According to one embodiment, the device is an ultra-wideband (UWB) radar device. Thus, established and economically important standards can be directly applied.

[0029] In the context of this document, the term "ultra-wideband" may refer to a radio technology that can use very low energy levels over a large portion of the radio spectrum for short-range, high-bandwidth communications. UWB may refer to a technology for transmitting information spread over a large bandwidth (e.g., 500 MHz). UWB may be defined as an antenna transmission that transmits a signal bandwidth exceeding the smaller of 500 MHz or 20% of the arithmetic center frequency. UWB transmissions can transmit information by generating radio energy at specific time intervals and occupying a large bandwidth. The range of UWB may be, for example, within a range of tens of meters. UWB (RF) ranging systems may use the time-of-flight principle to determine the distance between a mobile device and a target device (e.g., a car to be driven) and / or an anchor device (tag) on ​​the target device. Typically, a transmitter of a transceiver emits a waveform, typically a chirp or pulse, that is reflected by an object or retransmitted by a second transceiver. Based on the amount of time it takes for the reflection or retransmission to reach the receiver of the initiator transceiver, the distance between the objects can be calculated. The range between the receiver and the transmitter so determined is then used as a control point (to achieve access). In the same manner, UWB may be used to deliver payloads.

[0030] In this context, "UWB" may include impulse radio ultra-wideband (IR-UWB) (see, for example, standards IEEE802.15.4a and IEEE802.15.4z). In another embodiment, another radar solution may be applied, for example, based on WiFi, Bluetooth, NFC, RFID, etc. (specifically, according to a certain standard).

[0031] According to an embodiment, the calibration basis refers to at least one of the following: main peak; most main peak; main multipath component; target peak; self-interference peak. Thus, the calibration basis can be selected efficiently and in a flexible manner depending on the desired application.

[0032] In this context, a "dominant peak" may be the highest / strongest peak in the CIR or one of the highest / strongest peaks in the CIR (e.g., one of the three most dominant peaks). In one example, the calibration basis exists in each of the channel responses applied for calibration / splicing (multipath).

[0033] In the context of this document, the term "target" may specifically refer to an entity (e.g., an object, a person, an animal, etc.) to be investigated by, for example, radar, specifically in terms of spatial characteristics such as position, velocity, etc. Thus, a "target peak" may be a detected response signal caused by reflections of a transmitted RF signal from a target. For example, a CIR may be calculated from reflections of an RF signal, and a target peak may be one or more peaks in the CIR resulting from reflections at a target. Based on the target peak, a target phase (the phase of the received reflected RF signal) may be determined.

[0034] According to an embodiment, the first channel response includes a first self-interference peak, and / or the second channel response includes a second self-interference peak (see, e.g. Figure 6 ). Specifically, the calibration / alignment process includes: aligning the first self-interference peak with the second self-interference peak. In other words: calibrating the first channel response and the second channel response based on the first phase of the first self-interference peak and / or the second phase of the second self-interference peak. Therefore, the phase (phase offset) of the CIR can be aligned based on the self-interference peak / phase.

[0035] In the context of this document, the term "self-interference" may refer to signals that are not caused by a target but are caused by signal interference within a (radar) device. An example may be interference between a transmitter and a receiver of the radar device. Such self-interference may also be referred to as spill-over, cross-coupling, crosstalk, etc. Figure 6 A specific example of self-interference is shown in FIG. Within the CIR, one or more self-interference peaks may be visible. Based on the one or more self-interference peaks, a self-interference phase may be determined, and calibration may be performed based on the self-interference phase.

[0036] According to an embodiment, calibration is performed to correct for a constant phase offset and / or a steered phase offset between a first channel response and a second channel response. According to an embodiment, steering is performed to center a first phase of the first channel response and a second phase of the second channel response to obtain coherence of the first channel response and the second channel response.

[0037] According to an embodiment, the control device is further configured to: process at least one of the first channel response, the second channel response, and the combined channel response. Using one or more processing schemes, the device output quality (particularly, resolution / precision) can be further improved. In a preferred example, the processing can reduce / minimize the side lobes next to the main lobe in the CIR. In an example, the pre-processing and / or post-processing can be performed, for example, based on (spectral) filtering.

[0038] According to an embodiment, the device comprises three or more channels,

[0039] Two or more channels are adjacent and / or two or more channels are not adjacent. This solution can realize flexible combination of channels.

[0040] According to an embodiment, the device further comprises a receiver for receiving the signal,

[0041] Wherein the receiver comprises a first channel and a second channel. According to an embodiment, the apparatus comprises: i) a transmitter transmitting a (first and / or second) signal; and ii) a receiver receiving reflections (of one or more targets) of the signal.

[0042] In one example, the receiver comprises a first channel and a second channel. In one example, the receiver comprises a first receiver unit having a first channel and a second receiver unit having a second channel. Thereby, an RF device, such as a radar device, can be provided in a simple manner.

[0043] According to an embodiment, at least one of the first self-interference peak / phase and the second self-interference peak / phase is generated at least in part by coupling between a transmitter and a receiver. According to an embodiment, the transmitter is associated with the receiver. According to an embodiment, the transmitter and the receiver share a common antenna. According to an embodiment, the transmitter and the receiver are implemented in the same unit or in different units. According to an embodiment, the transmitter and the receiver are co-located.

[0044] According to one embodiment, a system is described, the system comprising:

[0045] i) an RF device as described above; and

[0046] ii) a target from which a radar (RF) signal is reflected, wherein the target is a moving target or a fixed target.

[0047] According to an embodiment, the first channel response is a first channel impulse response (CIR). According to an embodiment, the second channel response is a second CIR. According to an embodiment, the first channel response is associated with a first spectrum. According to an embodiment, the second channel response is associated with a second spectrum. According to an embodiment, the combined channel response is associated with a combined spectrum.

[0048] According to one embodiment, the channels are configured according to IEEE standards, such as IEEE 802.15.4-2020, Chapter 15.4.1, which describes the RF requirements of the HRP UWB PHY standard.

[0049] According to an embodiment, the calibration phase (particularly the main peak / phase) is associated with a target, in particular, wherein at least one property of the target (e.g., position, speed, size, type) is known. Thus, efficient steering to the target peak can be achieved (which requires the highest resolution / precision).

[0050] According to an embodiment, the method further comprises: applying the combined channel response to determine the spatial characteristics. Thereby, the spatial characteristics can be determined in an efficient and reliable manner. The spatial characteristics may include the location / position of the target in space, the distance to the target, the number of targets, the speed of the target, etc. Methods such as time difference of arrival (TDoA) or angle of arrival (AoA) may be applied hereby.

[0051] According to an embodiment, through calibration and steering, the (UWB) sub-bands can be coherently combined, even for non-adjacent bands. According to an embodiment, sweeps of these bands can be detected, especially in the case of using non-adjacent bands (as in the above example with channels 5 and 9).

[0052] According to one embodiment, the control device is further configured to, in the case where the first peak (e.g., target peak) is not the strongest peak (highest and / or widest peak, most dominant peak) in the first channel response and / or the second channel response (and / or combined channel response): identify the strongest peak (acquisition path), define a calibration base window based on the identified strongest peak (specifically, in the channel response before the strongest peak), and iteratively turn on the calibration base window to identify the first peak (first path). Thus, efficient calibration can be performed based on the peak of interest (first peak, target peak), thereby avoiding distortion.

[0053] In other words, the acquisition path is the strongest component of the CIR, while the first path is the physically earliest component, which may not necessarily be the strongest, for example due to line-of-sight obstruction and / or diffuse multipath propagation. When the strongest peak is selected as the calibration basis and steered towards it, the actual peak of interest (specifically, the first peak) may be distorted and therefore weaker (see e.g. Figure 5 ). The calibration base window can be chosen to be located before the strongest peak in time.

[0054] It may for example iterate over the CIR taps before acquiring the path, in particular using a certain threshold. Thus, the first peak may be identified and the distortion may be resolved. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 An RF device according to an exemplary embodiment of the present disclosure is shown.

[0056] Figure 2 An exemplary embodiment according to the present disclosure compares different channel impulse responses, including a combination of two adjacent channels.

[0057] Figure 3 According to an exemplary embodiment of the present disclosure, different channel impulse responses are compared, including a combination of four adjacent channels.

[0058] Figure 4 Exemplary embodiments according to the present disclosure compare different channel impulse responses, including combinations of non-adjacent channels.

[0059] Figure 5 An RF device according to an exemplary embodiment of the present disclosure is shown in a configuration in which a target peak value is selected as a calibration basis.

[0060] Figure 6 An RF device according to an exemplary embodiment of the present disclosure is shown in a configuration in which a self-interference peak is selected as a calibration basis.

[0061] Fig. 7A and 7B It is schematically illustrated that steering and splicing are performed according to an exemplary embodiment of the present disclosure.

[0062] Figure 8 A comparison of channel impulse responses from a conventional device and an RF device according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0063] Before describing the embodiments in more detail with reference to the drawings, some basic considerations upon which the embodiments of the present disclosure are formed will be outlined.

[0064] According to an exemplary embodiment, multiple (UWB) sub-band channel measurements in baseband are processed consecutively in the following blocks:

[0065] 1) Correcting for constant phase offset (if present, due to hardware effects),

[0066] 2) Apply a steering phase offset (only required if step 1) is required),

[0067] 3) Apply linear phase to shift to the splice band.

[0068] After running through these blocks, the signals are added together to obtain the output signal.

[0069] According to an exemplary embodiment, blocks 1) and 2) may require an additional pre-processing block, where the initial strongest multipath component is estimated (calibrated basis) to obtain:

[0070] i) accurate estimation of phase offset, and

[0071] ii) A rough estimate of the delay of the strongest path.

[0072] The latter is used in step 2) to recover the propagation channel dependent phase rotation. For monostatic radar systems, the accuracy of this pre-processing block may be optional, since there is a deterministic self-interference component available to the estimator.

[0073] In case there are spectral gaps between subbands, the stitching coherence can be given only for the calibration / steering basis (near the strongest component).

[0074] According to an exemplary embodiment, the application of ultra-wideband (UWB) radio measurements achieves decimeter-level accuracy for ranging and time-of-flight based systems. This accuracy is proportional to the bandwidth of the measurement. The proposed method combines consecutive UWB channel impulse response measurements to obtain a single resulting signal, where the bandwidths of all sub-signals are added together, thus increasing the ranging accuracy. Each sub-signal consists of a UWB sub-channel, where the center frequency and bandwidth can be arbitrary. The signals are closely fitted in the frequency domain to obtain a coherent "splice". The inter-band coherence of this splice depends on i) the presence of phase offsets and ii) the compactness of the sub-bands.

[0075] According to an exemplary embodiment, a combination of multiple sub-bands is described to extend the effective bandwidth. The sub-bands can also be obtained arbitrarily from the available channel pool.

[0076] Figure 1 An RF device 100 according to an exemplary embodiment of the present disclosure is shown. The RF device 100 includes a control device 110 (e.g., one or more processors) coupled (directly or remotely, e.g., wired or wirelessly) to a plurality of channels 120 (channel inputs). The RF device 100 is, in this example, a UWB radar device configured according to IEEE standards. A transmitter is not shown in this example, but a receiver is shown by the input channels 120. The transmitter transmits one or more RF radar signals, which are then reflected by a target. The reflected radar signals are then received by the channels of the receiver 120. Alternatively, an RF signal from another entity may be received.

[0077] The receiver 120 comprises in this example two (sub) channels: a first channel 121 with a first frequency band and a second channel 122 with a second frequency band. In this example, baseband channels 5 and 9 of the IEEE standard are applied. It should be noted that these channels 121, 122 are not adjacent to each other, i.e. there is a frequency gap between them. The first channel 121 is configured to receive a first signal, while the second channel 122 is configured to receive a second signal. The signals may be the same for the channels or different for each channel 121, 122. The first channel 121 measures a first channel response as a first channel impulse response, and the second channel 122 measures a second channel response as a second channel impulse response. These channel impulse responses are then sent to the control device 110.

[0078] The control device 110 is configured to obtain the channel impulse response (CIR) and combine the first CIR with the second CIR by channel splicing 112 to obtain a combined channel (impulse) response 115 (ie, a combined spectrum) as output. Figure 1As can be seen from the figure, channel splicing 112 is based on the number of frequency bands (n) and the center frequency (f st ) and: n*f st ,in

[0079] f st =f st (1) +ΔB i

[0080] In order not to lose information, the sampling rate can be scaled with the number of frequency bands when calculating the output sum, for example resampling T s ->T s / N B .

[0081] Before performing the actual channel stitching 112, calibration 111 is applied to align the first CIR and the second CIR with each other. In order to perform such alignment, it is necessary to estimate the parameters (steering vectors) In the present case, a calibration basis 130 is determined, which in this example is selected to estimate The most dominant peak of the channel impulse response (strongest multipath component, at position n0, n0->max) of the channel impulse response is obtained. Based on the calibration basis 130, a steering towards the calibration basis 130 is performed for the first CIR and the second CIR in order to obtain / correct the phase offset and coherence between the CIDs.

[0082] In other words, a three-step process can be applied: calibration (determining the calibration basis), steering (towards the calibration basis, steering to center the subband phases to obtain inter-band coherence), and splicing (combining). The equation (r_st) shown is an illustrative overview of all three steps in one round:

[0083] i) r_BB is the CIR from a single channel (in baseband),

[0084] ii) these first obtain the calibration phase shift phi_0 (here obtained from the strongest peak), and iii) then obtain the steering (n_0*ΔB) (here the distance between the position of the strongest peak and the center frequency), and

[0085] iv) Finally, concatenation (n*f_st) (linear phase to shift the frequency band).

[0086] Figure 2 Different channel impulse responses are compared according to an exemplary embodiment of the present disclosure, including a combination of two adjacent channels. On the left, a CIR plot is shown, where the amplitude is indicated at the y-axis and the path length in meters is indicated at the x-axis. Three peaks are visible in the CIR plot, which may be associated with a target and / or a surface, for example. The following CIRs are shown:

[0087] i) the CIR of the first (sub)channel 121 having a center frequency at 6.5 GHz (bandwidth 500 MHz),

[0088] ii) the CIR of the adjacent second channel 122 having a center frequency at 7 GHz (bandwidth 500 MHz),

[0089] iii) Combined CIR, whereby the first CIR and the second CIR have been calibrated and stitched together,

[0090] iv) A single channel with double bandwidth (no splicing) to illustrate that splicing can properly double the bandwidth.

[0091] The term "circular AWGN" refers to a noise model that is circular additive white Gaussian noise to simulate a more realistic channel.

[0092] On the right, a detailed view of the dominant peak 130 (the strongest multipath component) is shown.

[0093] At the top, it is schematically shown that the bandwidths of two adjacent channels 121, 122 (each 500 MHz) are combined by splicing to a combined bandwidth of 1 GHz, thereby effectively doubling the bandwidth.

[0094] It can be seen that the combined (stitched) channel CIR has significantly higher accuracy / resolution as the single channel CIR.The dominant peak 130 can be used as a calibration basis in this example to calibrate / align the first CIR with the second CIR.

[0095] Figure 3 Different channel impulse responses are compared according to an exemplary embodiment of the present disclosure, including a combination of four adjacent channels. On the left, a CIR plot is shown, where the amplitude is indicated at the y-axis and the path length in meters is indicated at the x-axis. Three peaks are visible in the CIR plot, which may be associated with a target and / or a surface, for example. The following CIRs are shown:

[0096] i) the CIR of the first (sub)channel 121 having a center frequency at 6.5 GHz (bandwidth 500 MHz),

[0097] ii) the CIR of the adjacent second channel 122 having a center frequency at 7 GHz (bandwidth 500 MHz),

[0098] iii) a combined CIR whereby the first CIR, the second CIR, the third CIR from the third channel 123 having a center frequency at 7.5 GHz, and the fourth CIR from the fourth channel having a center frequency at 8 GHz have been calibrated and stitched together,

[0099] iv) A single channel with four times the bandwidth (no splicing) to illustrate that splicing can appropriately quadruple the bandwidth.

[0100] On the right, a detailed view of the dominant peak 130 (the strongest multipath component) is shown.

[0101] At the top, it is schematically shown that the bandwidths of four adjacent channels 121, 122, 123, 124 (each 500 MHz) are combined by splicing into a combined bandwidth of 2 GHz, thereby effectively obtaining four times the bandwidth.

[0102] It can be seen that the combined (stitched) channel CIR has significantly higher accuracy / resolution as a single channel CIR.The dominant peak 130 can be used as a calibration basis in this example to calibrate / align the first CIR, the second CIR, the third CIR, and the fourth CIR.

[0103] Figure 4 Different channel impulse responses are compared according to an exemplary embodiment of the present disclosure, including a combination of four non-adjacent channels. On the left, a CIR plot is shown, where the amplitude is indicated at the y-axis and the path length in meters is indicated at the x-axis. Three peaks are visible in the CIR plot, which may be associated with a target and / or a surface, for example. The following CIRs are shown:

[0104] i) the CIR of the first (sub)channel 121 having a center frequency at 6.5 GHz (bandwidth 500 MHz),

[0105] ii) the CIR of an adjacent second channel 122 having a center frequency at 7.25 GHz (bandwidth 1 GHz),

[0106] iii) a combined CIR, whereby the first CIR, the second CIR, and a fourth CIR from a fourth channel having a center frequency at 8 GHz have been calibrated and stitched together, whereby a frequency gap 140 exists between the second frequency band and the fourth bandwidth,

[0107] iv) A single channel with four times the bandwidth (no splicing) to illustrate that splicing can appropriately quadruple the bandwidth.

[0108] On the right, a detailed view of the dominant peak 130 (the strongest multipath component) is shown.

[0109] At the top, it is schematically shown that the bandwidths of two adjacent channels 121, 122 (a first channel and a second channel) and a non-adjacent fourth channel 124 are combined by splicing into a combined bandwidth of 2 GHz, thereby effectively obtaining four times the bandwidth.

[0110] It can be seen that the combined (stitched) channel CIR has significantly higher accuracy / resolution as a single channel CIR.The dominant peak 130 can be used as a calibration basis in this example to calibrate / align the first CIR, the second CIR, and the fourth CIR.

[0111] Figure 5 The RF device 100 (see FIG. 1 ) according to an exemplary embodiment of the present disclosure is shown in the following configuration. Figure 1 ): where the target peak 131, rather than the main peak 130, is selected as the calibration basis. In this example, there is a gap 140 between the applied first channel 121 bandwidth and the fourth channel 124 bandwidth. Looking closely at the main peak 130 (left side), distortion can be seen, while the target peak 131 (right side) does not show distortion. Therefore, the target peak 131 (area) can be determined with high accuracy / resolution, while the main peak 130 (area) cannot be determined with high accuracy / resolution. Therefore, the described bandwidth doubling is achieved for a specific target tap (at the target peak 131 area).

[0112] Figure 6 The RF device 100 (see FIG. 1 ) according to an exemplary embodiment of the present disclosure is shown in the following configuration. Figure 1 ): wherein the self-interference peak 132 is selected as the calibration basis 130. For this particular example, the RF device 100 is configured as a monostatic radar, where the transmitter and the receiver are co-located, i.e. arranged in the same entity. The interference between the transmitter and the receiver generates a (device-specific) self-interference peak 132 in each CIR. In this way, the self-interference peak 132 can be used as a calibration basis and can be calibrated / steering independently of the target. Thereby, for example, the resolution of two or more (spatially close) targets can be improved.

[0113] Fig. 7A and 7B Schematically illustrates an algorithm for performing steering 114 and splicing 112 to find the (real earliest) first path when the strongest peak (acquisition path) is not the first path according to an exemplary embodiment of the present disclosure. Thus, the acquisition path is the strongest component of the CIR, while the first path (first peak) is the physically earliest component, which may not necessarily be the strongest component, for example, due to line-of-sight obstruction and / or diffuse multipath propagation. The basic idea of ​​this algorithm comes from Figure 5 Effect seen in : A turn towards the strongest peak (acquisition path) may make the target peak (first path) distorted and / or weaker. Following the algorithm shown, it iterates over the CIR taps before acquiring a path, and each time turns according to the corresponding distance. When the first path is reached, then the distortion is resolved and the threshold should be exceeded.

[0114] This algorithm works well for cases where there are gaps in the spectrum, but can also be used when there are no gaps, since the initial steering to obtain the peak may not be completely accurate, and iterating as described above can result in the correct steering distance (d_0) and therefore help find the true first path.

[0115] Fig. 7A : CIR estimation, detection threshold and noise estimation are shown. In the backward search window, the acquisition path and the first path are shown.

[0116] Figure 7B :Schematically shows about Fig. 7A The above first path search algorithm for CIR estimation of . The steering coefficient is calibrated on the strong tap (acquisition path). Iteratively, when the first path is found, the steering coefficient is then adjusted to the first path search position and the algorithm is stopped.

[0117] for Figure 8 , the conventional example has been described above. However, according to the present disclosure, a bandwidth of B=1 GHz can be applied, and the resolution and accuracy can be significantly improved.

Claims

1. A device (100), wherein the device (100) is a radio frequency (RF) device (100), characterized in that: include: A first channel (121), the first channel (121) having a first frequency band and configured to receive a first signal; a second channel (122) having a second frequency band configured to receive a second signal, wherein the first frequency band is different from the second frequency band; and A control device (110), wherein the control device (110) is configured to: obtaining a first channel response associated with a received first signal at the first channel (121); obtaining a second channel response associated with the received second signal at the second channel (122); calibrating (111) the first channel response and the second channel response by turning (114) to a calibration basis (130); as well as The first channel response is combined with the second channel response by channel concatenation (112) to obtain a combined channel response (115).

2. The device (100) according to claim 1, characterized in that The first frequency band and the second frequency band are adjacent to each other or are not adjacent to each other.

3. The device (100) according to claim 2, characterized in that There is a frequency gap (140) between the first frequency band and the second frequency band.

4. The device (100) according to any of the preceding claims, characterized in that The device (100) is an ultra-wideband (UWB) device.

5. The device (100) according to any of the preceding claims, characterized in that The calibration basis (130) is associated with at least one of: Main peak (130); The most important peak; Dominant multipath components; TargetPeak(131); Self-interference peak (132).

6. The device (100) according to claim 5, characterized in that Calibration (111) is performed to correct at least one of the following between the first channel response (121) and the second channel response (122): Constant phase offset, Steering phase shift.

7. The device (100) according to claim 5 or 6, characterized in that Steering (114) is performed to center a first phase of the first channel response and a second phase of the second channel response to obtain coherence of the first channel response and the second channel response.

8. The device (100) according to any of the preceding claims, characterized in that The control device (110) is further configured to: At least one of the first channel response, the second channel response, and the combined channel response (115) is processed.

9. A method of operating a radio frequency (RF) device (100), characterized in that: The method comprises: obtaining a first channel response associated with a received first signal at a first channel (121) having a first frequency band; obtaining a second channel response associated with a received second signal at a second channel (122) having a second frequency band, wherein the first frequency band is different from the second frequency band; calibrating (111) the first channel response and the second channel response by turning (114) to a calibration basis (130); and The first channel response is combined with the second channel response to obtain a combined channel response (115), wherein the combining includes channel concatenation (112).

10. A use of a diversion (114) to a calibration basis (130), characterized in that Used for calibrating channels (121, 122) with non-adjacent frequency bands by channel splicing (112).

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