Technical Field

The present disclosure relates generally to wireless communication, and in particular to power management of antenna modules in a device for wireless communication.

Background Art

As mobile data usage continues to grow, future mobile networks are anticipated to utilize higher-frequency radio bands. Millimeter- wave (mmWave) communications, for example, using carrier frequencies in the range of 24-300 GHz, offer huge improve ments in bandwidth compared to existing mobile networks. However, radio propagation is more challenging in high-frequency ranges and beamforming is generally proposed for both communication devices (UEs) and base stations (BSs) to compensate for path loss. To enable beamforming, UEs will include a large number of antenna elements, which may be arranged and controlled in modules. The use of multiple modules at the UE would enable reception of signals in a challenging environment where UE move ment, rotation, or beam blockage would benefit from transmit and receive signal diversity. However, the use of multiple antennas may lead to significant power consumption in the UE. For example, according to prior art techniques, to save power, the UE may de-activate a subset of the modules and periodically activate all modules to monitor signal quality, and then selectively activate only those modules that provide sufficient signal quality. However, the periodic activation of all modules still results in significant power consumption.

The foregoing is relevant for any UE that comprises two or more antenna modules that may be switched between a low-power state and a high-power state. Such UEs may be configured for communication in any type of wireless network, including 3GPP (Third Generation Partnership Project) networks, 3GPP LTE (Long Term Evolution) networks, 3 GPP LTE- A (LTE Advanced) networks, and fifth -generation (5G) networks including new radio (NR) networks, as well as networks in accordance with, for example, WiMAX and IEEE802.11 standards. Summary

It is an objective to at least partly overcome one or more limitations of the prior art.

A further objective is to enable a reduced power consumption in a device for wireless communication that comprises antenna modules operable in low- and high- power states.

One or more of these objectives, as well as further objectives that may appear from the description below, are at least partly achieved by a device for wireless communication, and a method in accordance with the independent claims, embodiments thereof being defined by the dependent claims.

A first aspect of the present disclosure relates to a device for wireless communication. The device comprises: antenna modules operable to receive and transmit wireless signals, wherein a respective antenna module comprises antenna elements for generating antenna signals corresponding to incoming wireless signals, and wherein the respective antenna module is operable in a low-power state and a high- power state. The device further comprises control logic which is configured to, repeatedly, when a first antenna module among the antenna modules is in the low- power state: generate a time-dependent power signal representing a combined power of the antenna signals of the antenna elements in the first antenna module; determine, based on an output signal provided by a second antenna module in the high-power state, a time point for an incoming wireless reference signal; determine a power value in the time-dependent power signal based on the time point; and evaluate the power value in relation to a criterion for setting the first antenna module in the high-power state.

In the first aspect, the configuration of the control logic provides for power management of one or more antenna modules in the device. Specifically, the power consumption of an antenna module in the low-power state may be reduced, since the determination of the power value may be implemented without the need to energize power-consuming circuitry in this antenna module. In some embodiments of the first aspect, the power consumption of the antenna module in the low-power state may be close to zero, even if the device is repeatedly operated to monitor received signal power at this antenna module. Further, the configuration of the control logic for determining the power value may replace conventional analog bandpass filtering, for example in frequency ranges where such analog bandpass filtering is difficult or costly to implement, such as in the mmWave spectrum. A second aspect of the present disclosure relates to a method for power management of antenna modules in a device for wireless communication, the antenna modules being operable to receive and transmit wireless signals, wherein a respective antenna module comprises antenna elements for generating antenna signals corresponding to incoming wireless signals, and wherein the respective antenna module is operable in a low-power state and a high-power state. The method is performed repeatedly when a first antenna module among the antenna modules is in the low-power state. The method comprises: generating a time-dependent power signal representing a combined power of the antenna signals of the antenna elements in the first antenna module; determining, based on an output signal provided by a second antenna module in the high-power state, a time point for an incoming wireless reference signal; determining a power value in the time-dependent power signal based on the time point; and evaluating the power value in relation to a criterion for setting the first antenna module in the high-power state.

Any embodiment of the first aspect as described herein may be adapted and implemented as an embodiment of the second aspect, and vice versa.

Still other objectives, as well as features, embodiments, aspects and advantages may appear from the following detailed description, from the attached claims as well as from the drawings.

Brief Description of the Drawings

Embodiments will now be described in more detail with reference to the accompanying drawings.

FIG. l is a schematic view of a communication device operable to communicate with a base station and/or another communication device.

FIGS 2A-2B illustrate examples of selective activation of antenna modules in a communication device subject to reference signals transmitted by a base station.

FIG. 3 is a block diagram of example circuitry in a communication device in accordance with an embodiment.

FIG. 4A is a flow chart of an example method of performing power management in a communication device in accordance with an embodiment, and FIGS 4B-4C are flow charts of example methods for generating a time-dependent power signal in accordance with embodiments.

FIG. 5 is a block diagram of an example power detector in a communication device in accordance with an embodiment.

FIG. 6 is a block diagram of example circuitry in a communication device in accordance with an embodiment.

FIG. 7 is a flow chart of an example method of operating an antenna module in a communication device in accordance with an embodiment. Detailed Description of Example Embodiments

Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the subject of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure may satisfy applicable legal requirements.

Also, it will be understood that, where possible, any of the advantages, features, functions, devices, and/or operational aspects of any of the embodiments described and/or contemplated herein may be included in any of the other embodiments described and/or contemplated herein, and/or vice versa. In addition, where possible, any terms expressed in the singular form herein are meant to also include the plural form and/or vice versa, unless explicitly stated otherwise. As used herein, "at least one" shall mean "one or more" and these phrases are intended to be interchangeable. Accordingly, the terms "a" and/or "an" shall mean "at least one" or "one or more", even though the phrase "one or more" or "at least one" is also used herein. As used herein, except where the context requires otherwise owing to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, that is, to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments.

As used herein, the terms "multiple", "plural" and "plurality" are intended to imply provision of two or more elements, whereas the term a "set" of elements is intended to imply a provision of one or more elements. The term "and/or" includes any and all combinations of one or more of the associated listed elements.

It will furthermore be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing the scope of the present disclosure.

Well-known functions or constructions may not be described in detail for brevity and/or clarity. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

As used herein, "antenna module" denotes a combination of a set of antenna elements and associated circuitry, said combination being operated independently from other antenna elements and/or antenna modules and being switchable into different power states or modes independent of other antenna elements and/or antenna modules. The set of antenna elements in the antenna module may be arranged in one or more groups or arrays. The antenna module may be a physically separate component or be a functionally defined part of a component, which may or may not contain one or more further antenna modules. In some embodiments, the antenna module may also be denoted "antenna panel".

As used herein, "antenna element" refers to a single antenna.

As used herein, "low-power state" (LPS) and "high power state" (HPS) of an antenna module denote two operating states that differ by power consumption and available functionality of the antenna module. In some embodiments, the LPS corresponds to a state in which the antenna module is deactivated for use in wireless communication, for example control signaling and/or data communication, and the HPS corresponds to a state in which the antenna module is activated to enable wireless communication, for example control signaling and/or data communication. In some embodiments, circuitry for signal conversion to and, optionally, from baseband, such as a receiver and transmitter, is deactivated in LPS and activated in HPS. In some embodiments, where the antenna module comprises dedicated circuitry for performing baseband processing, at least the baseband processing circuitry is deactivated in LPS and activated in HPS. It may be noted that an antenna module may comprise one or more further operating states that involve a power consumption below and/or above LPS and/or HPS.

Even if the disclosure may use the term "power", it is understood that the disclosure is equally applicable to the term "energy", since energy and power waveforms are proportional for a given integration time.

Like numerals refer to like elements throughout.

Even if the following description may use terminology that is specific to a particular wireless communication standard, such as 5G NR (New Radio), embodiments are not so limited and are applicable to any communication technology, for example as discussed in the Background section.

FIG. 1 illustrates a communication device 10, denoted UE in the following, which comprises a processing system 11 and three antenna modules 12A, 12B, 12C. The processing system 11 is configured to selectively activate the antenna modules 12A-12C and to process output signals from the antenna modules 12A-12C to perform the regular operation of the UE 10, for example wireless communication, interaction with the user, etc. The UE 10 may be a mobile device, a computer, a wearable device, a vehicle, etc. The communication may be performed by exchange of communication signals with a base station 20 and/or another UE 10'. In the example of FIG. 1, the antenna modules 12A-12C are spatially well-separated on the UE 10, to improve the ability of the UE 10 to receive communication signals despite UE movement, rotation, or beam blockage.

To preserve power in the UE 10, the processing system 11 may activate a subset of the antenna modules 12A-12C and keep remaining antenna modules deactivated. To enable communication, at least one antenna module needs to be active. In a conventional approach, this may be achieved by the processing system 11 periodically activating the respective antenna module to monitor signal quality, and then keeping the antenna module(s) that exhibit an acceptable signal quality active, while deactivating all other antenna modules. The effect of such selective activation/deactivation is illustrated in FIGS 2A-2B. In FIG. 2A, antenna module 12B is activated for communication with the base station 20, whereas antenna modules 12 A, 12C have been deactivated after a finding of inferior signal quality in relation to signals transmitted by the base station 20. In FIG. 2B, antenna modules 12A, 12B are activated for communication with the base station 20, whereas antenna module 12C has been deactivated. It is to be understood that the signal quality at the respective antenna module 12A-12C will change as the environment and/or position of the UE 10 changes, requiring frequent activation of the antenna modules 12A-12C. Signal quality may be monitored by determining a signal parameter such as RSSI, RSRP, or RSSQ for an incoming reference signal. Such a signal parameter may be determined by baseband processing, for example involving down-conversion to baseband, sampling and digital filtering. According to this approach, all antenna modules need to be periodically activated for measuring signal quality of reference signals, which is power consuming.

The reference signal may be any downlink signal transmitted by a base station 20 or a sidelink signal transmitted by another UE 10' (cf. FIG. 1). In the context of 5G NR, the reference signal may be an SSB (synchronization signal block) or an CSI-RS (channel state information reference signal).

As a prior art alternative to baseband processing, a power detector may be included in the antenna module, where the power detector comprises an analog bandpass filter for isolating a reference signal received by the antenna elements of the antenna module and an analysis unit for determining the power of the isolated reference signal. In this context, "isolating" implies that the bandpass filter is transmissive in a relatively narrow frequency range around the carrier frequency of the reference signal. However, analog filtering is difficult to achieve at reasonable cost and size in the frequency range above 6 GHz, and even more so in the mmWave spectrum, for example in Frequency Range 2 (FR2) used in 5G R. For example, acoustic filters that are conventionally used for RF filtering sub-6, such as SAW and BAW filters, exhibit degradation in selectivity at frequencies greater than 6 GHz. Thus, there is presently no commercially available analog bandpass filter for use in a power detector, and the antenna modules therefore need to be periodically activated for baseband processing to determine signal quality.

Embodiments described herein serve to improve power management of antenna modules in a device for wireless communication and are particularly, but not exclusively, useful at carrier frequencies greater than 6 GHz, for example mmWave communications using carrier frequencies in the range of 24-300 GHz. Specifically, embodiments enable an antenna module in a communication device to be operated to monitor signal strength even when it is deactivated for communication.

FIG. 3 is a block diagram of example circuitry in a communication device (for example UE 10) in accordance with an embodiment. The circuitry comprises a processing system 11, which may include a processing device or processor such as a central processing unit (CPU), graphics processing unit (GPU), microcontroller, microprocessor, ASIC, FPGA, or any other specific or general processing device. The processing system 11 may execute instructions stored in a computer memory 13, which may comprise one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or another suitable data storage device. The instructions when executed by the processor may control the operation of the communication device, or at least the power management of its antenna modules. The instructions may be supplied to the memory 13 on a computer-readable medium, which may be a tangible (non -transitory) product (for example magnetic medium, optical disk, read-only memory, flash memory, etc.) or a propagating signal. The circuitry further comprises antenna modules 12A-12C. In FIG. 3, only antenna 12A is illustrated in detail, but it is to be understood that all antenna modules 12A-12C may be of identical or similar structure.

In the illustrated example, the antenna module 12A comprises a plurality of antenna elements 12G, which may be arranged in one or more groups 121 (one indicated by dashed lines). The antenna module 12A further comprises a receiver (RX) 123, which may be part of a conventional front-end module and is connected between the antenna elements 121 and a baseband processing system (BB) 124. The RX 123 is configured to receive analog RF receive signals ("incoming antenna signals") from the antenna elements 12G and provide corresponding baseband signals to the BB 124. The BB 124 is configured to process the baseband signals and provide corresponding data output signals Ola to the processing system 11. In some embodiments, for example as shown, the antenna module 12A may also comprise a transmitter (TX) 122, which is configured to generate analog RF transmit signals ("outgoing antenna signals") based on output signals from the BB 124 and provide the analog RF transmit signals to the antenna elements 12G. It is understood that the BB 124 may generate the output signals based on input signals (not shown) from the processing system 11.

The structure and operation of TX 122, RX 123 and BB 124 are well-known to the skilled person and will not be described further.

The antenna module 12A further comprises a power detector (PD) 130, which is connected to receive the incoming antenna signals and provide a power output signal Olb to the processing system 11. The structure and functionality of the PD 130 will be described in more detail below.

The processing system 11 is operable to provide control signals Cl a, Clb to the antenna module 12A. In FIG. 3, control lines for control signals are represented by dashed lines for clarity of presentation. The control signal C la is a module enable signal that causes TX 122 (if present), RX 123 and BB 124 to be either fully operational for communication ("activated" or "energized"), or completely turned off ("de-activated" or "de-energized"). Thus, the control signal Cla may be provided to selectively cause the antenna module 12A to switch between HPS and LPS. The control signal Clb is optional and may be a PD enable signal that causes the PD 130 to be either operational ("activated") or turned off ("deactivated"). In a variant, the PD 130 is always operational. As will be described further below, the control signal Clb may alternatively or additionally include timing information for the operation of the PD 130.

As indicated in FIG. 3, the processing system 11 is arranged to provide corresponding control signals C2a, C2b, C3a, C3b to the antenna modules 12B, 12C and to receive corresponding output signals 02a, 02b, 03a, 03b from the antenna modules 12B, 12C. The processing system 11 is thereby operable to selectively cause the respective antenna module 12B, 12C to operate in and switch between HPS and LPS.

Thus, in some embodiments, the respective antenna module 12A-12C comprises conversion circuitry 122, 123 for signal conversion to baseband. In such embodiments, the conversion circuitry 122, 123 may be de-activated in the low-power state (LPS) and activated in the high-power state (HPS).

Further, in some embodiments, the respective antenna module 12A-12C comprises baseband processing circuitry 124. In such embodiments, the baseband processing circuitry 124 may be de-activated in the low-power state (LPS) and activated in the high-power state (HPS).

FIG. 4A is a flow chart of an example method 400 for power management of antenna modules in a communication device in accordance with an embodiment. The example method presumes that the communication device comprises at least two antenna modules and that at least one of the antenna modules is currently in LPS (denoted "LPS antenna module" in the following, and may also be designated "first antenna module") and at least one other antenna module is currently in HPS (denoted "HPS antenna module" in the following, and may also be designated "second antenna module"). Thus, in the situation of FIG. 2B, the LPS (or first) antenna module is any one of modules 12A, 12C, and module 12B is an HPS (or second) antenna module. In the situation of FIG. 2C, the LPS (or first) antenna module is module 12C, and modules 12A, 12B are HPS (or second) antenna modules. As will be explained in more detail below, the example method 400 allows the communication device to significantly reduce the power consumption of the antenna modules in the LPS, by clever processing of incoming antenna signals from the antenna elements 12G. In fact, depending on implementation, the example method 400 may reduce the power consumption in LPS to close to zero. Further, the example method 400 obviates the need for conventional analog bandpass filtering for isolating and determining the signal strength of a wireless reference signal that is received by one or more antenna elements of an antenna module.

The example method 400 comprises steps 401-404 which are performed repeatedly for each antenna module that is currently in LPS. Step 401 generates a time- dependent power signal to represent a combined power of the antenna signals of the antenna elements in the LPS antenna module. Step 402 determines a time point for an incoming wireless reference signal based on an output signal from at least one HPS antenna module. Step 403 determines a power value in the time-dependent power signal based on the time point, and step 404 evaluates the power value in relation to a criterion for switching the LPS antenna module to HPS.

The example method 400 may be performed by the example circuitry in FIG. 3, specifically by a combination of the power detector 130 in the LPS antenna module and the processing system 11. This combination is also referred to as "control logic" herein. If the outcome of step 404, in one or more of the repetitions of the example method 400, indicates that the reference signal has a sufficient signal strength at an antenna module, for example module 12A, this antenna module may be switched from LPS to HPS, by the processing system 11 providing a corresponding control signal Cla to module 12 A.

Thus, some embodiments relate to a device 10 for wireless communication. The device 10 comprises antenna modules 12A-12C operable to receive and transmit wireless signals, wherein a respective antenna module 12A-12C comprises antenna elements 12G for generating antenna signals corresponding to incoming wireless signals, and wherein the respective antenna module 12A-12C is operable in a low- power state and a high-power state. The device 10 also comprises control logic 11, 130 which is configured to, repeatedly, when a first antenna module (e.g., 12C in FIG. 2A) among the antenna modules 12A-12C is in the low-power state: generate a time- dependent power signal representing a combined power of the antenna signals of the antenna elements 12 G in the first antenna module 12C; determine, based on an output signal provided by a second antenna module (e.g., 12B in FIG. 2 A) in the high-power state, a time point for an incoming wireless reference signal; determine a power value in the time-dependent power signal based on the time point; and evaluate the power value in relation to a criterion for setting the first antenna module 12C in the high -power state.

To explain the rationale for the example method 400, consider an antenna module comprising M antenna elements, where the respective antenna element receives an antenna signal y _m (t). At a carrier frequency f _c , a reference signal of bandwidth W Hz is present. Outside the nominal bandwidth [f _c — W/2,f _c + W /2], the antenna signals y _m (t) may contain interference. Mathematically, the antenna signals may be represented as: where n _m (t ) designates noise, / _m (t) designates the interference, s(t) designates the reference signal, and h _m (t ) designates the impulse response at antenna element m. The example method 400 in FIG. 4A serves to detect, in a low-power fashion, whether a quantity representative of the signal strength of the reference signal at the antenna module is large enough so that it is meaningful to switch the antenna module to HPS ("activate" the module). It should be understood that the interference I _m (t) may be significant and needs to be suppressed or eliminated for the signal strength to be determined.

Reverting to FIG. 4 A, step 401 is performed by the PD 130 in FIG. 3 and results in a time-dependent power signal that not only includes the combined power of the reference signal, if received by the antenna elements of the LPS antenna module, but also the combined power of the interference received by the antenna elements. Thus, the power signal may be largely dominated by unknown contributions from the interference / _m (t). The example method 400 is based on the insight that the timing of the reference signal may be obtained by the UE 10, by use of an antenna module which is operated in HPS and thus enables wireless communications, e.g. control signaling (via TX and/or RX) and/or data transmission/reception. In other words, the UE 10 may be time- synchronized with the base station 20 or the UE 10' via the currently active antenna module(s), i.e. the HPS antenna module(s). This means that the UE 10 is capable of determining, from the data output signal of an HPS antenna module (cf. Ola, 02a, 03a in FIG. 3), the transmit times of the reference signal in relation to the time reference system that the UE 10 has in common with the device that transmits the reference signal. Thus, generally, the UE 10 knows the transmit times and/or periodicity of the reference signal, which also means that the UE 10 knows the expected time of reception of the reference signal at the HPS antenna module. This expected time of reception may be set as or converted into an expected time of reception of the reference signal at the LPS antenna module. The provision of this timing information enables step 402 of method 400. Here, it is understood that the antenna modules of the UE 10 may be synchronized with each other, for example by factory calibration. It should also be understood that step 402 need not be performed for every repetition of the method 400, but the timing information determined by step 402 at one time instance may be applied by step 403 at any number of time instances. In step 403, the UE 10 samples the power signal provided by step 401 at the time point(s) provided by step 402 ("sampling times"), to acquire one or more power values that represent the signal strength of the reference signal at the LPS antenna module. Such time-synchronized sampling will reduce the influence of the interference on the outcome of the evaluation in step 404. Depending on implementation, the sampling in step 403 may be performed by the PD 130 or the processing system 11.

Thus, in some embodiments, the time point determined by step 402 represents an expected time of reception of the incoming wireless references signal by the first antenna module (e.g. 12C in FIG. 2A)

In some embodiments, when the reference signal is an SSB, the UE 10 may be notified, via communication through one or more HPS antenna modules in the UE 10, by the base station 20 or the UE 10' (FIG. 1) of an SSB-based measurement timing configuration (SMTC) window that includes the SSB period and timing.

In some embodiments, the sampling times may depend on the UE location. For example, if the UE 10 is on the edge of a current cell, the sampling times may be decided based on timing information for not only the base station 20 of the current cell, but also for one or more base stations that define one or more neighboring cells.

In some embodiments, step 402 may be performed by the processing system 11, which may determine sampling times from the data output signal of one or more HPS antenna modules and provide the sampling times to step 403.

In some embodiments, step 402 may be performed by the respective HPS antenna module, which may provide the sampling times to step 403.

In some embodiments, step 401 comprises generating an aggregated signal comprising a time sequence of aggregated power values for the antenna signals of the antenna elements in the LPS antenna module, and generating the time-dependent power signal as a function of the aggregated signal. Each aggregated power value in the aggregated signal represents the total received signal power at the antenna elements in the LPS antenna module at one time instance. In a variant, the timing information representing the sampling times may be obtained from the HPS antenna module at a time point preceding the execution of the method 400. This variant presumes that conditions are substantially invariant over the relevant timespan, for example that the reference signal is deterministic, the drift of electronic components such as oscillators is small, and that the location of the UE is relatively stable. Thus, although the example method in FIG. 4 presumes that the LPS and HPS antenna modules are different antenna modules in the UE, it is conceivable that, under certain circumstances, the timing information for an antenna module currently in LPS may be obtained from the same antenna module when previously in HPS.

FIG. 4B is a flow chart of an example procedure for generating the power signal in step 401. In step 410, the respective antenna signal y _m (t) is converted into a time sequence of antenna power values, for example given by y^(t). Such conversion may be performed by conventional low-power hardware. In step 411, the time sequences of antenna power values are combined into the above-mentioned aggregated signal, for example by summation.

In some embodiments, the aggregated signal generated by step 411 may form the power signal which is provided (by step 413) to step 403 for processing. However, as shown in FIG. 4B, an intermediate step 412 may be provided to generate the power signal by applying a low-pass filter (LPF) to the aggregated signal. Low-pass filtering may significantly improve the quality of the power signal, by further reducing the influence of the above-mentioned interference. In some embodiments, when the carrier frequency f _c is above 6 GHz, the LPF may have a cut-off frequency below 6 GHz. As explained in the following, significant improvement may be achieved by using a significantly lower cut-off frequency, for example below 100 kHz. It should be understood that the signal of interest in the respective antenna signal y _m (t), namely h _m (t) * s(t), has a spectral guard-band with respect to the interference / _m (t). This should be understood to imply that the reference signal is spectrally concentrated to a small portion of the bandwidth, and there is a guard-band around the reference signal. Therefore, the interference / _m (t) is well-separated from the reference signal in the spectral domain. Spectral analysis of y^(t) reveals that there are no mixing terms between h _m (t ) * s(t) and I _m (t) in the spectral range of [— G, G] Hz, where G is the width of the guard-band. In this spectral range, there are thus only contributions from I h _m (t) * s(t)| ² and |/ _m (t)| ² . Therefore, to avoid mixing terms, which may degrade subsequent performance, an LPF with a cutoff frequency less than G may be operated on the aggregated signal from step 411. In some embodiments, G is 1 MHz or larger. Further, the LPF may be tailored to single out the reference signal. In this context, "single out" implies that the impulse response of the LPF is roughly of the same duration as the reference signal. In some embodiments, the duration of the reference signal is in the range 30-300 ps. This implies that an LPF that singles out the reference signal, for example a moving-average filter, may have a cutoff frequency in the order of 3-30 kHz. The filtered output signal of the LPF may then form the power signal, which is output by step 413 for use by step 403.

Thus, in some embodiments, the control logic 11, 130 is further configured to: generate a time sequence of aggregated power values for the antenna signals of the antenna elements 12G in the first antenna module (e.g., 12C in FIG. 2A), and generate a filtered signal by operating a low-pass filter 133 on the time sequence of aggregated power values, wherein the time-dependent power signal is generated as a function of the filtered signal.

Further, in some embodiments, the low-pass filter 133 has a cut-off frequency that approximately corresponds to a duration of the incoming wireless reference signal.

In the example of a moving average filter, the filtered signal of the LPF at time t may be described as:

As understood from the foregoing, the integration time T may be set approximately equal to the duration of the reference signal.

Reverting to step 403 in FIG. 4A, the sampling of the power signal E'(t ) at a time point t _end at the end of the reference signal, results in a sampled power value E _s = E'(t _end ) ~ E _RS + E _j , where E _RS is the energy of the reference signal, i.e., the quantity to be measured, and E _j is the energy of the interference. The time point t _end may be given by step 402.

FIG. 5 is a block diagram of an example PD 130. The PD 130 is configured to receive M antenna signals yi(t), ... ,y _M (t ) and to output sampled power values E _s. A first block 131 is configured to perform step 410 in FIG. 4B and may be implemented by a low-power analog multiplier with two inputs, where the respective antenna signal ... , y _M (t) is supplied at both inputs. Such an analog multiplier is also known as a self-mixing receiver or self-down-converter. The analog multiplier may include a non linear component. If the non-linear component is a diode, the analog multiplier is known as a diode detector. The non-linear component, when fed with the antenna signal, generates multiplication products including a difference that represents the square of the antenna signal, that is centered on zero frequency and that is a low- frequency signal. The squared antenna signals y (t), ... , y^(t) are received by a second block 132, which is configured to perform step 411 in FIG. 4B to generate the aggregated signal E(t). A third block 133 implements step 412 in FIG. 4B and operates an LPF on the aggregated signal to generate the power signal E'(t). In a hardware implementation, the third block 133 may comprise a plurality of LPFs with different cutoff frequencies, or a tunable LPF, so that the cut-off frequency of the low-pass filtering may be adjusted to reference signals of different duration. A fourth block 134 implements step 403 in FIG. 4A and samples values in the power signal E'(t) in accordance with time points that are determined by step 402, to generate the sampled power values E _s. In the example of FIG. 5, the timing information representing the time points is comprised in a control signal C, which may be generated, depending on implementation, by the processing system 11 or an HPS antenna module. In one example, the control signal C may be one of the PD enable signals Clb, C2b, C3b shown in FIG. 3.

In an alternative embodiment, the fourth block 134 is omitted and the sampling in accordance with step 403 is instead implemented by the processing system 11.

In some embodiments, the blocks 131-133 define dedicated analog circuitry for generating the power signal E'(t). Such analog circuitry may be manufactured at low complexity and low cost and may be highly power efficient.

Thus, in some embodiments, the device 10 comprises dedicated analog circuitry 130 for generating the time-dependent power signal E'(t).

FIG. 4C is a flow chart of another example procedure for generating the power signal E'(t). Compared to the procedure in FIG. 4B, the procedure in FIG. 4C differs by steps 410' and 41 G, which generate the aggregated signal E(t). In step 410', the antenna signals yi(t), ... ,y _M (t ) are combined into a combined antenna signal. This combination may be performed by analogy with step 411 in FIG. 4B. Thus, in some embodiments, the antenna signals yi(t), ...,y _M (t) may be combined without phase offset, which results in a combined antenna signal for a bore-sight beam direction of the antenna elements. Additionally or alternatively, the antenna signals yi(t), ...,y _M (t) may be combined by use of a predefined set of phase offsets. Specifically, step 410' may apply an individual phase offset to the respective antenna signal and then combine the thus- offset antenna signals. The skilled person understands that the predefined set of phase offsets may define a dedicated beamforming direction, i.e. a selected spatial focus for the signal reception at the antenna elements.

In some embodiments, step 410' may apply different predefined sets of phase offsets, which are defined to address different sub spaces of the available coverage space of the antenna elements. Thus, step 410' may result in plural combined antenna signals which represent received signals in different subspaces in relation to the antenna module. In other words, step 410' may cover predefined angles from the LPS antenna module with a predefined number of beams, resulting in a corresponding number of combined antenna signals.

In step 41 G, the respective combined antenna signal is converted into time sequences of received power values, by analogy with step 410 in FIG. 4A. Based on the teachings herein, the skilled person is readily able to modify the first and second blocks 131, 132 in FIG. 5 to implement steps 410', 41 G. As understood from the foregoing, the second block 132 may generate aggregated signals E(t) for different beamforming directions. Such aggregated signals may, for example, be processed in parallel by a respective third block 133 and, optionally, by a respective fourth block 134. Alternati vely, the aggregated signals may be processed in sequence, for example by use of delay circuits or, if the aggregated signals are digital, by intermediate storage in memory.

Thus, in some embodiments, the control logic 11, 130 is configured to generate the time-dependent power signal E'(t) for a first direction in relation to the first antenna module (e.g., 12C in FIG. 2A), and the control logic 11, 130 is further configured to generate a second time-dependent power signal E'(t) representing the combined power of the antenna signals of the antenna elements 12G in the first antenna module 12C for a second direction in relation to the first antenna module 12C; determine a second power value Es in the second time-dependent power signal based on the time point (from step 402), and evaluate the second power value Es in relation to the criterion CR1 for setting the first antenna module in the high-power state.

In the example of FIG. 3, the PD 130 is included in the respective antenna module 12A-12C. In alternative embodiments, the PD 130 may be physically separated from the respective antenna module 12A-12C. In other embodiments, one PD 130 may be connected to plural antenna modules. An example is shown in FIG. 6, in which a switching block 140 is arranged to selectively connect a power detector 130 to receive antenna signals from a respective antenna module among a plurality of antenna modules 12A-12C. The switching block 140 may be triggered by control signals from the pro cessing system 11 to connect one of the antenna modules 12A-12C to the PD 130. In the illustrated example, the switching block 140 is triggered by the control signals Cla-C3a, for example to switch an antenna module to the PD 130 whenever the control signal sets the antenna module in LPS. In the example of FIG. 6, the timing information for use by step 403 is comprised in a control signal C provided by the processing system 11.

Reverting to FIG. 4A, step 404 may be implemented in various ways. In some embodiments, step 404 evaluates a time sequence of sampled power values E _s , determined by step 403 at consecutive time points, for detection of a trend indicative of presence or absence of the reference signal. If the trend is indicative of presence, step 404 may signal a switch from LPS to HPS. In some embodiments, step 404 evaluates the respective sampled power value E _s in relation to a threshold value. If a sufficient number of consecutive power values exceed the threshold value, step 404 may signal a switch from LPS to HPS. The sufficient number may be any number. The threshold value may be predefined or dynamically determined, for example as described below with reference to FIG. 7.

Thus, in some embodiments, the criterion used by step 404 comprises at least one of a threshold value to be exceeded by the power value, and a trend of the power value in relation to preceding and/or subsequent power values.

FIG. 7 is flow chart of an example control method 700 that incorporates several embodiments that, alone or in any combination, may further improve the power management of the antenna modules. It may be noted that the method 700 comprises a step 701 that comprises steps 401-404 in FIG. 4A and involves, by step 404, evaluating one or more power values from an LPS antenna module in relation to a first criterion, designated by CR1. If CR1 is deemed to be fulfilled, the antenna module is switched to HPS by step 702. In the following, to simplify the discussion, the method 700 is assumed to only perform power management of a single antenna module. In practice, however, the method 700 may perform power management of all or any combinations of antenna modules in a UE.

The method 700 further comprises an embodiment for determination of the above- mentioned threshold value. In the method 700, step 707 switches the antenna module from HPS to LPS. Following such a switch, step 708 determines the threshold value based on one or more sampled power values E _s provided by step 404. In one implementation, step 708 determines a time-average for a time sequence of sampled power values and sets the threshold value to or as function of the time-average. In one example, the threshold value is computed as the time-average multiplied by a constant. The constant may be determined by testing or simulation to attain a desired robustness of step 404. If the constant is too small, step 404 may result in many false activations of the antenna module. If the constant is too large, the antenna module may remain de activated although it has received significant power. The underlying rationale for step 708 is that the antenna module is switched to LPS whenever step 707 finds that the reference signal is unlikely to be received by the antenna module, which means that the sampled power values E _s determined by step 403 mainly represent the energy of the interference (cf. £) above). Since the interference signals / _m (t) are wide-band random signals, the law of large numbers (LLN) is applicable. This law infers that the mean value of £) will be comparable to the instantaneous value of E so after scaling with the mean value, measured over time, the variance vanishes. This means that the value of £) may be considered deterministic and may be used for determining the threshold value. Step 708 may be performed immediately following step 707 and may be repeated one or more times to ensure consistency of the estimated value of £).

Thus, in some embodiments, the control logic 11, 130 is further configured to compute a time-average of the time-dependent power signal when the first antenna module (e.g., 12C in FIG. 2A) has been set into the low-power state, and generate the threshold value as a function of the time-average.

The method 700 also includes an embodiment in which, after the antenna module has between switched to HPS, the UE 10 checks whether this was indeed the correct decision or if the antenna module was erroneously activated, for example by measuring the actual false activation probability of the antenna module.

In some embodiments, the control logic 11, 130 is configured to set the first antenna module (e.g., 12C in FIG. 2A) in the high-power state when the criterion CR1 is fulfilled, and the control logic 11, 130 is further configured to, when the first antenna module 12C has been set in the high-power state, measure signal quality of a further incoming wireless reference signal in relation to a further criterion (e.g., CR2 below). If the further criterion is unfulfilled, the control logic 11, 130 is configured to return the first antenna module 12C to the low-power state. In some embodiments, the further incoming wireless reference signal is the same signal as the previously mentioned incoming reference signal.

In other words, this check may be performed by the processing system 11 and may involve determining if the further incoming wireless reference signal is strong enough, by some criterion, using the full logic available for the antenna module. For example, with reference to the example in FIG. 3, RX 122 and BB 124 of a selected antenna module may be operated to provide output data (cf. Ola, 02a, 03a) that allows the processing system 11 to verify if the selected antenna module was correctly activated. In FIG. 7, this embodiment is implemented by step 703, which is performed subsequent to step 702, which switches the antenna module from LPS to HPS. Step 703 may evaluate the reference signal and/or a further reference signal in relation to a second criterion, designated by CR2, and, if CR2 is unfulfilled, proceed to step 704 which returns the antenna module to LPS. As understood from the foregoing, step 703 may involve the antenna module performing baseband processing of the antenna signals from its antenna elements, to provide an output signal for evaluation in relation to CR2. The second criterion CR2 may relate to any parameter of the reference signal such as RSPR, RSPQ, RSSI, etc., or any combination thereof. If CR2 is fulfilled, step 703 may proceed to step 706 which operates the antenna module in HPS.

Thus, in some embodiments, when the first antenna module has been set in HPS, steps 703-704 measure signal quality of a further incoming wireless reference signal in relation to a second criterion CR2, and, if the second criterion CR2 is unfulfilled, return the first antenna module to LPS.

Further, in some embodiments, step 703 measures signal quality of the further incoming wireless reference signal in relation to the second criterion CR2 by operating circuitry in the antenna module, when switched from LPS to HPS, to convert the antenna signals to baseband, by performing baseband processing of the thus-converted antenna signals for determining a parameter value representative of the incoming wireless reference signal, and by evaluating the parameter value in relation to the second criterion CR2.

The method 700 also includes an embodiment in which the decision to activate the antenna module is not only based on the outcome of the evaluation in step 404. Instead, measurements from one or more other antenna modules of the UE 10 are also considered. These other antenna modules may be in LPS or HPS, and the measurements may include sampled power values E _s provided by the PD 130 for module(s) in LPS and parameter values generated from baseband processing for the module(s) in HPS. Potentially, all antenna modules of the UE 10 may be evaluated. The underlying rationale is as follows. Waves arriving to the UE 10 from specific directions imprint a well-defined power profile on the antenna modules of the UE 10. For example, a wave impinging on a display of the UE 10 is received more strongly by module(s) located on the front and, possibly, module(s) located on the top, bottom and laterals, whereas module(s) on the rear of the UE 10 will typically not receive this wave. It is therefore clear that appropriately leveraging measurements from several antenna modules may reduce the probability of false wake-up of antenna modules and/or the probability of missed activation of antenna modules. In FIG. 7, this embodiment may be implemented by step 701, by CR1 stipulating a relation between the sampled power value(s) E _s determined for the antenna module and parameter values that are representative of the reference signal and determined for at least one other antenna module.

Thus, in some embodiments, the criterion CR1 comprises a relation between the power value E _s and a parameter value that is representative of the incoming wireless reference signal and determined for at least one antenna module other than the first antenna module (e.g., 12C in FIG. 2A) in the device 10.

The method 700 also includes an embodiment in which the first criterion CR1 is adjusted whenever the second criterion CR2 is unfulfilled. The fact that CR2 is unfulfilled implies that CR1 is inadequate to prevent false activation of the antenna module. In the example of FIG. 7, the adjustment of CR1 is performed by step 705, which is performed when step 703 proceeds to switch the antenna module back to LPS. Step 705 may, for example, increase the above-mentioned threshold value. If CR1 accounts for measurements from one or more other antenna modules of the UE 10, as exemplified above, step 705 may selectively increase or decrease the relevance of such measurements for CR1.

Thus, in some embodiments, the control logic 11, 130 is further configured to, if the criterion CR2 is unfulfilled, modify the criterion CR1 for setting the first antenna module (e.g., 12C in FIG. 2A) in the high-power state.

While the subject of the present disclosure has been described in connection with what is presently considered to be the most practical embodiments, it is to be understood that the subject of the present disclosure is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and the scope of the appended claims.

For example, the embodiments described in the foregoing is equally applicable for antenna modules that do not include circuitry for baseband processing. Here, LPS and HPS may involve de-activation and activation, respectively, of the receiver and the transmitter (if present).

Further, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, parallel processing may be advantageous.

In the following, items are recited to summarize some aspects and embodiments as disclosed in the foregoing.

Item 1. A device (10) for wireless communication, said device comprising: antenna modules (12A-12C) operable to receive and transmit wireless signals, wherein a respective antenna module (12A-12C) comprises antenna elements (12G) for generating antenna signals corresponding to incoming wireless signals, and wherein the respective antenna module (12A-12C) is operable in a low-power state and a high- power state; and control logic (11, 130) which is configured to, repeatedly, when a first antenna module (12C) among the antenna modules (12A-12C) is in the low-power state: generate a time-dependent power signal (E'(t)) representing a combined power of the antenna signals of the antenna elements (12G) in the first antenna module (12C); determine, based on an output signal provided by a second antenna module (12B) in the high-power state, a time point for an incoming wireless reference signal; determine a power value (Es) in the time-dependent power signal based on the time point; and evaluate the power value (Es) in relation to a criterion (CR1) for setting the first antenna module (12C) in the high-power state.

Item 2. The device of item 1, wherein the antenna modules (12A-12C) are operable to receive and transmit the wireless signals with a carrier frequency above 6 GHz, more specifically above 24 GHz.

Item 3. The device of item 1 or 2, wherein the time point represents an expected time of reception of the incoming wireless reference signal by the first antenna module (12C).

Item 4. The device of any preceding item, wherein the control logic (11, 130) is further configured to: generate a time sequence (E(t)) of aggregated power values for the antenna signals of the antenna elements (12G) in the first antenna module (12C), wherein the time-dependent power signal (E'(t)) is generated as a function of the time sequence (E(t)).

Item 5. The device of item 4, wherein the control logic (11, 130) is further configured to: generate a filtered signal by operating a low-pass filter (133) on the time sequence (E(t)), wherein the time-dependent power signal (E'(t)) is generated as a function of the filtered signal.

Item 6. The device of item 5, wherein the low-pass filter (133) has a cut-off frequency below 6 GHz, below 100 kHz, or below 30 kHz.

Item 7. The device of item 5 or 6, wherein the low-pass filter (133) has a cut-off frequency that approximately corresponds to a duration of the incoming wireless reference signal.

Item 8. The device of any preceding item, wherein the criterion (CR1) comprises at least one of a threshold value to be exceeded by the power value (ERS), and a trend of the power value (ERS) in relation to preceding and/or subsequent power values.

Item 9. The device of item 8, wherein the control logic (11, 130) is further configured to compute a time-average of the time-dependent power signal (E'(t)) when the first antenna module (12C) has been set into the low-power state, and generate the threshold value as a function of the time-average.

Item 10. The device of any preceding item, wherein the criterion (CR1) comprises a relation between the power value (Es) and a parameter value that is representative of the incoming wireless reference signal and determined for at least one antenna module other than the first antenna module (12C) in the device. Item 11. The device of any preceding item, wherein the control logic (11, 130) is further configured to set the first antenna module (12C) in the high-power state when the criterion (CR1) is fulfilled.

Item 12. The device of item 11, wherein the control logic (11, 130) is further configured to, when the first antenna module (12C) has been set in the high -power state, measure signal quality of a further incoming wireless reference signal in relation to a further criterion (CR2), and, if the further criterion (CR2) is unfulfilled, return the first antenna module (12C) to the low-power state.

Item 13. The device of item 12, wherein the control logic (11, 130) is further configured to measure signal quality of the further incoming wireless reference signal in relation to the further criterion (CR2) by operating circuitry (123) in the first antenna module (12C) to convert the antenna signals to baseband, performing baseband processing of the thus-converted antenna signals for determining a parameter value representative of the incoming wireless reference signal, and evaluating the parameter value in relation to the further criterion (CR2).

Item 14. The device of item 12 or 13, wherein the control logic (11, 130) is further configured to, if the further criterion (CR2) is unfulfilled, modify the criterion (CR1) for setting the first antenna module (12C) in the high-power state.

Item 15. The device of any preceding item, wherein the control logic (11, 130) is configured to generate the time-dependent power signal (E'(t)) for a first direction in relation to the first antenna module (12C), and wherein the control logic (11, 130) is further configured to generate a second time-dependent power signal (E'(t)) representing the combined power of the antenna signals of the antenna elements (12G) in the first antenna module (12C) for a second direction in relation to the first antenna module (12C); determine a second power value (Es) in the second time-dependent power signal based on the time point, and evaluate the second power value (Es) in relation to the criterion (CR1) for setting the first antenna module (12C) in the high-power state.

Item 16. The device of any preceding item, which comprises dedicated analog circuitry (130) for generating the time-dependent power signal (E'(t)).

Item 17. The device of item 16, wherein the dedicated analog circuitry (130) is included in at least the first antenna module (12C).

Item 18. The device of any preceding item, wherein the incoming wireless reference signal is a downlink reference signal transmitted by a base station (20) or a sidelink reference signal transmitter by a further device (10').

Item 19. The device of item 18, wherein the downlink reference signal is an SSB or an CSI-RS. Item 20. The device of any preceding item, wherein the respective antenna module (12A-12C) comprises conversion circuitry (122, 123) for signal conversion to baseband, wherein said conversion circuitry (122, 123) is de-activated in the low-power state and activated in the high-power state.

Item 21. The device of any preceding item, wherein the respective antenna module (12A-12C) comprises baseband processing circuitry (124), wherein said baseband processing circuitry (124) is de-activated in the low-power state and activated in the high-power state.

Item 22. The device of any preceding item, wherein the second antenna module (12B) is separate from the first antenna module (12C) and is in the high-power state when the first antenna module (12B) is in the low-power state.

Item 23. A method for power management of antenna modules in a device for wireless communication, the antenna modules being operable to receive and transmit wireless signals, wherein a respective antenna module comprises antenna elements for generating antenna signals corresponding to incoming wireless signals, and wherein the respective antenna module is operable in a low-power state and a high-power state, said method being performed repeatedly when a first antenna module (12C) among the antenna modules (12A-12C) is in the low-power state, said method comprising: generating (401) a time-dependent power signal representing a combined power of the antenna signals of the antenna elements in the first antenna module; determining (402), based on an output signal provided by a second antenna module in the high-power state, a time point for an incoming wireless reference signal; determining (403) a power value in the time-dependent power signal based on the time point; and evaluating (404) the power value in relation to a criterion for setting the first antenna module in the high-power state.