Power control

Abstract

A method at a network node equipped with an advanced antenna system AAS is provided, where the AAS includes a plurality of antenna elements and one or more radio frequency integrated circuits RFICs, and where each RFIC of the one or more RFICs is associated with one or more of the plurality of antenna elements. The method includes: capturing (210) a plurality of signal samples of one or more signal chains of each RFIC of the one or more RFICs, where each signal chain of the one or more signal chains corresponds to one or more of the plurality of antenna elements, and the signal samples are associated with an envelope power level at the output of the corresponding signal chain; and summing (220) at least one subset of the plurality of signal samples to obtain a short-term average power value at the AAS.

Description

Field of the Invention

[0001] The present disclosure relates to the field of measurement or estimation of transmitted RF power and control of the average level of transmitted RF power, and more particularly to average power measurement or estimation and average power control at a network node equipped with an advanced antenna system (AAS). Background Art

[0002] The demand for bitrates in wireless communication systems continues to increase. The lower frequency spectrum is filled, and higher frequency spectrums must be used. Thus, in 5G cellular systems, new frequency ranges are introduced, denoted as frequency range 2 (FR2) (24250 MHz - 52600 MHz).

[0003] The main challenge at millimeter wave frequencies (mmW) is to ensure good enough coverage. There are many reasons for this, including extremely strong diffraction that makes strong shadowing effects prominent; the difficulty of obtaining a high enough transmitted power from radio frequency integrated circuits (RFICs); and the reduced antenna element area that has a direct impact on the calculated path loss from the transmitter baseband to the receiver baseband. It is currently known to introduce a large use of array antenna technology, called advanced antenna system (AAS). This technology helps to mitigate the problems listed above by means of a sharply increased beam gain, increasing the rated equivalent isotropic radiated power (EIRP) of mmW base stations to a suitable level, and compensating for the increased coupling loss between base station and user equipment antennas due to the generally reduced antenna size.

[0004] In FR2, beamforming (BF) and beam control are achieved by coherently combining the RF signals from each antenna element of the AAS. By phase shifting and amplifying the signals of the antenna elements, a desired beam is formed.

[0005] A low complexity way of performing beamforming is analog BF, where the signals going to / from the antennas are beamformed in the RF domain close to the antennas. The rest of the signal chain is common for all or some of the antennas. What then happens is that all data is converted to a time domain stream early on before being sent to the RFIC and the antennas. Since a set of beam weights is applied during one orthogonal frequency division multiplexing symbol, the beam is spatially fixed for all data. Although it may have peaks in multiple directions, the data stream will be transmitted through one beam pattern, which limits the possibility of transmitting data to multiple users simultaneously. This can be a problem when it would be beneficial to direct or receive direct data streams in different directions through frequency selective scheduling. In addition, there may also be problems when a user equipment (UE) tries to find a base station for initial access. Current FR2 AAS systems use beam scanning or a wider initial beam to counter these problems, but it increases the cost in terms of coverage, latency, and / or capacity.

[0006] In contrast, digital beamforming uses inverse fast Fourier transform (IFFT) processing to transform complex orthogonal frequency division multiple access (OFDMA) symbols into data streams in a timely manner, where each user independently accesses all antenna elements, thus allowing frequency-selective beamforming. However, this does require IFFT processing with increased complexity in the RFIC, or alternatively, in the case of baseband IFFT processing, this does require an interface bandwidth for the IFFT data stream.

[0007] The second-generation FR2 systems aim at higher capacity and more connected users. This poses challenges to analog beamforming methods and imposes increasing overhead for beam management. To counter the capacity requirements, hybrid beamforming or digital beamforming can be used. This allows multiplexing of users in both the frequency domain (FDM) and the spatial domain (SDM). The number of antennas remains high (in the range of several hundreds), and the bandwidth is increasing and approaching approximately 1 GHz.

[0008] By connecting RFIC analog and digital radios with transmitters and receivers to each antenna element, there will be complete freedom to perform arbitrary beamforming in the digital domain. The transmitter section can include a digital-to-analog converter (DAC), a low-pass filter, an up-conversion mixer, a programmable gain amplifier, a band-pass filter, and a power amplifier. The receiver section can include a low-noise amplifier (LNA), a band-pass filter, a digital step attenuator, a down-conversion mixer, a low-pass filter, and an analog-to-digital converter (ADC). A phase-locked loop (PLL) for generating the clocks required for up-conversion / down-conversion mixing may exist between the transmitter section and the receiver section. The digital part of the transmit chain at the RFIC starts with receiving the time-domain data stream from the IFFT processing in the central unit. Then, the RFIC can perform digital up-conversion (DUC), crest factor reduction (CFR), and send the data stream through a digital pre-distortion (DPD) block. After that, the data can be converted from digital to analog.

[0009] When deploying any radio equipment, radio frequency (RF) electromagnetic field (EMF) exposure rules need to be considered. These exposure limits are generally based on the guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), but may take different forms in some countries and regions. The purpose of RF EMF exposure rules is to ensure that human exposure to RF energy is kept within the specified limits, which have been set with a wide safety margin.

[0010] For 5G millimeter wave base stations and radios equipped with AAS, it is also necessary to ensure compliance with RF EMF exposure limits. These AAS increase coverage by adding antenna arrays that significantly increase beamforming gain. As a result, the EMF is concentrated in certain beam directions. As a further result, the methods traditionally used to calculate RF exposure compliance distances and exclusion zones based on the maximum EIRP of nodes tend to generate significantly increased compliance distances and exclusion zones. This can lead to deployment challenges.

[0011] However, ICNIRP and other RF EMF exposure limits in frequency bands suitable for wireless communication are expressed as the average power density (W / m 2 ) over a specified time interval T. Depending on the frequency and the regulation, this averaging time is on the order of seconds or minutes. Therefore, relevant to the use when determining RF exposure compliance is the time-averaged EIRP, and the instantaneous EIRP can be significantly higher than the average EIRP during a time period shorter than T. Given the distance at which compliance with RF exposure needs to be ensured, the power density limit can be transformed into a corresponding threshold of the time-averaged total transmitted power. However, the average power transmitted must remain below the determined power threshold, which is calculated to obtain a specific exclusion zone. Therefore, control functionality that ensures the average power is below the limit 100% of the time is needed.

[0012] Figure 1 Two implementations of proportional and integral (PI) control using a dynamic scheduler limiter are shown, which can be applied in embodiments of the present disclosure for average power control. For ease of reference, the implementation shown at the top in Figure 1 will be referred to herein as the "first implementation", and the implementation shown at the bottom in Figure 1 will be referred to herein as the "second implementation". Compared with the first implementation, the second implementation includes a precipitation factor integrator that can be applied in embodiments of the present disclosure.

[0013] The relationship between the parameters of the first implementation and the parameters of the second implementation can be obtained in the following formula by equating the coefficients for equal measures (degrees) of s:

[0014] .

[0015] To obtain a smooth behavior of the dynamic resource threshold that is applied in the scheduler to limit the output power, rate control of the control signal sent to the limiter for command adjustment (i.e., increase or decrease) is needed, or equivalently, the dynamic threshold system includes the previous integration of a PI controller. The determination of the dynamic characteristics (dynamic resource threshold) of the actuator mechanism can be represented by the following formula:

[0016]

[0017] where is the dynamic resource threshold, and u(t) is the control signal, which will be discussed in more detail below. t represents continuous time. This is consistent with the factoring PI control structure discussed in reference Figure 1 The dynamic resource threshold is decoupled from the scheduler algorithm itself, and it represents the fractional limit of the scheduler such that it does not use more than a fraction of its total resources . Then, the scheduler can limit the number of frequency resource physical resource blocks (PRBs), or any other quantity that is strongly correlated with the short-term transmission power.

[0018] The maximum value of

[0019] is 1.0 because this is used to represent the fraction of the maximum amount of scheduler resources. It is also necessary to limit its lower bound to prevent the dynamic feedback control mechanism from reducing it to a non-physical value below 0.0. Therefore, the following scheduler threshold limits represented by the formula below can be applied each time:

[0020] An alternative approach would be to use information available in the scheduler or elsewhere in the baseband to replace the measured power with the predicted output power. This quantity can be obtained, for example, by summing the PRBs allocated by the scheduler at each moment over time T.

[0021] However, this method is affected by many errors. These errors include, for example, the actual power error caused by power sharing between retransmissions, power boosts, and transport layer errors, as well as the errors caused by radio signal processing near the antenna (including, for example, clipping to achieve crest-to-average power reduction), and antenna alignment errors. In addition, the regulatory agency may not accept the baseband prediction and requires measurements close to the AAS.

[0022] To make this alternative method feasible, the total short-term average output power applied by the RFIC to one or more antenna elements of the AAS should be measured. There is currently no available solution on how to achieve this. Therefore, measurement functionality for measuring short-term average power values near the antenna elements is required on the RFIC. SUMMARY OF THE INVENTION

[0023] One aspect of the present disclosure provides a method at a network node equipped with an advanced antenna system (AAS), where the AAS includes a plurality of antenna elements and one or more radio frequency integrated circuits (RFICs), and where each of the one or more RFICs is associated with one or more of the plurality of antenna elements. The method includes: capturing a plurality of signal samples of one or more signal chains of each of the one or more RFICs, where each of the one or more signal chains corresponds to one or more of the plurality of antenna elements, and the signal samples are associated with an envelope power level at the output of the corresponding signal chain; and summing at least one subset of the plurality of signal samples to obtain a short-term average power value at the AAS.

[0024] Another aspect of the present disclosure provides a computer program product including a computer-readable medium having computer-readable code embodied therein, the computer-readable code being configured to, when executed by a suitable computer or processor, cause the computer or processor to perform the method as described herein.

[0025] Another aspect of the present disclosure provides a network node equipped with an advanced antenna system (AAS), where the AAS includes a plurality of antenna elements and one or more radio frequency integrated circuits (RFICs), and where each of the one or more RFICs is associated with one or more of the plurality of antenna elements. The network node includes processing circuitry configured to: capture a plurality of signal samples of one or more signal chains of each of the one or more RFICs, where each of the one or more signal chains corresponds to one or more of the plurality of antenna elements, and the signal samples are associated with an envelope power level at the output of the corresponding signal chain; and sum at least one subset of the plurality of signal samples to obtain a short-term average power value at the AAS. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To better understand examples of the present invention and to more clearly show how the examples may be implemented, reference will now be made, by way of example only, to the following drawings, in which:

[0027] Figure 1 Shows two implementations of PI control using a dynamic scheduler limiter, which can be applied in embodiments of the present disclosure for average power control;

[0028] Figure 2 Is a flowchart showing a method at a network node equipped with an advanced antenna system according to an embodiment;

[0029] Figure 3 is a block diagram of a network node according to an embodiment; and

[0030] Figure 4 shows an example of a feedback control mechanism applicable in embodiments of the present disclosure for controlling short-term average power. DETAILED DESCRIPTION

[0031] Thus, embodiments of the present disclosure allow for the measurement of the average power close to the antenna element on the RFIC, thereby ensuring AAS deployment in cases where short-term average power measurement is required as a basis for average power control for RF EMF exposure limit compliance. In addition, embodiments of the present disclosure provide methods for obtaining representative short-term average power values along the signal chain in a manner that prevents systematic errors, such as systematic errors that occur when selecting the synchronization time at each signal sample capture. The embodiments described herein relate to deterministic components for avoiding the recurrence of such transmission events occurring at fixed time points, and random sampling components for selecting, for example, the intervals at which signal samples are selected for capture at the signal chain.

[0032] Figure 2 is a flowchart showing a method at a network node equipped with an advanced antenna system (AAS) according to an embodiment. The method shown can generally be performed by a computer or a processor or be performed under the control of a computer or a processor. The AAS includes a plurality of antenna elements and one or more radio frequency integrated circuits (RFICs), and each of the one or more RFICs is associated with one or more of the plurality of antenna elements.

[0033] In addition, in some embodiments, the AAS may further include a radio unit configured to be connected to the baseband unit via an interface (e.g., via a C2 interface). In some of these embodiments, the baseband unit may further include a scheduling unit.

[0034] Reference Figure 2 , at step 210, a plurality of signal samples of one or more signal chains of each of the one or more RFICs are captured. In some embodiments, each of the one or more signal chains may correspond to one or more of the plurality of antenna elements, and the signal samples are associated with the envelope power level at the output of the corresponding signal chain. In some embodiments, more than one signal chain may be combined, and the combined signal chain group may correspond to one or more of the plurality of antenna elements. This combination may be in the digital domain or in the analog / RF domain.

[0035] In some embodiments, capturing each signal sample of a plurality of signal samples of one or more signal chains of each RFIC at step 210 may include: detecting an in-phase component and a quadrature-phase component of the corresponding signal, and squaring the in-phase component and the quadrature-phase component of the corresponding signal.

[0036] In addition, in some embodiments, detecting the in-phase component and the quadrature-phase component of the corresponding signal may include one of the following: detecting the in-phase component and the quadrature-phase component over a predetermined time period; and detecting a predetermined number of in-phase components and quadrature-phase components.

[0037] In some embodiments, capturing a plurality of signal samples at step 210 may be performed at one or more predetermined intervals. Each of the one or more predetermined intervals may have a predetermined duration, such as 10 ms. In addition, capturing a plurality of signal samples at step 210 may be performed over a plurality of predetermined intervals, and the time elapsed between the plurality of predetermined intervals may be based on a predetermined pattern. In some embodiments, the predetermined pattern may be a random pattern.

[0038] Returning to Figure 2 , at step 220, summing at least one subset of the plurality of signal samples to obtain a short-term average power value at the AAS. The short-term average power value may be considered to represent a short-term average power estimate of a large number of time-varying signal vector samples (e.g., I / Q samples) carrying information to be modulated into an output RF signal at each of a plurality of antenna elements. In some embodiments, the process of obtaining the short-term average power value may involve averaging a certain buffer length of consecutive signal samples. In the context of the present disclosure, the expression "short-term" may be considered to refer to time frames in the range of 1 ms to 100 ms, while "long-term" may be considered to refer to time frames in the range of 1 minute to 30 minutes.

[0039] It should be understood that in some cases, 100% of all signal samples may be captured at all times, and a moving average may be determined. Alternatively, the results associated with individual buffers may be determined one at a time. In some embodiments, not all 100% of the streaming signal samples may be captured, and then only a buffer of consecutive signal samples may be captured (e.g., with a 10% duty cycle, which captures 10% of all signal samples and omits 90% of all signal samples). For example, a specific pattern may be used to capture a 1 ms buffer, wait for 9 ms, and then capture the next buffer. In some cases, it may be necessary to avoid periodic events in the streaming signal samples so as not to cause an undesired bias in the signal sample capture. This may be achieved, for example, by introducing a randomized starting point for each 1 ms buffer.

[0040] In some embodiments, the short-term average power value at the AAS can be represented by the following formula:

[0041]

[0042] where P tot (t) is the short-term average power value at the AAS, is the short-term average power value according to the RFIC (measured / estimated within a predetermined interval (“frame”)), and L is the number of RFICs in the AAS. The determination of will be explained in more detail in the following paragraphs.

[0043] In some embodiments, summing at least one subset of a plurality of signal samples at step 220 may include: for each RFIC of the plurality of RFICs, summing at least one subset of the plurality of signal samples of each signal chain of the corresponding RFIC to obtain the short-term average power value according to the RFIC, and summing the plurality of short-term average power values according to the RFIC to obtain the short-term average power value at the AAS. The short-term average power value according to the RFIC can be represented by the following formula:

[0044]

[0045] where is the short-term average power value according to the RFIC (measured / estimated within a predetermined interval (“frame”)), and is the signal sample at the corresponding signal chain, and M is the number of antenna elements in the AAS. The determination of

[0046] will be explained in more detail in the following paragraphs. The above formula, i.e., formula (5), assumes one antenna element per signal chain, but it will be readily understood that in alternative embodiments, the formula can be modified for different arrangements.

[0047]

[0048] wherein, is a signal sample at the corresponding signal chain, N is the number of signal samples measured during a predetermined time interval, and i is the ordinal number of the signal sample in the sequence of N signal samples, is the square of the in-phase component of the corresponding signal at time t i and is the square of the quadrature-phase component of the corresponding signal at time t i .

[0049] In some embodiments, the signal samples at the corresponding signal chain may be normalized, and in other embodiments, the signal samples may not be normalized. In some embodiments, the square root of the sum / integral of the square in-phase component and the square quadrature-phase component may be determined during an operation of determining the average value of the signal samples at the signal chain.

[0050] Although not shown in Figure 2 , in some embodiments, the method may further include: configuring a power meter point for each of the plurality of signal chains before capturing a plurality of signal samples of one or more signal chains of each of the plurality of RFICs at step 210. In these embodiments, the power meter point is configured to capture the signal samples of the corresponding signal chain. Configuring the power meter point may include allocating the corresponding power meter point at a relative position along the corresponding signal chain. The relative position allocated in the corresponding signal chain may be after a crest factor reduction (CFR) block in the corresponding signal chain. Thus, the corresponding power meter point may be configured to perform the corresponding measurement before digital predistortion occurs at the digital predistortion (DPD) block (at the RFIC).

[0051] Due to running closed-loop DPD adaptation, the corresponding position of the power meter point allows for precise signal capture and thus senses the transmitted power through reuse of the receiver section of the RFIC. The DPD block is also subject to extensive internal power sensing monitoring to ensure precise operation. Through the adaptation of the DPD, a scaling factor may be established between the digital data at the input of the DPD and the corresponding instantaneous power transmitted from the output of the signal chain. Thus, appropriate scaling factors may also be established for different positions of the power meter and the output of the signal chain.

[0052] Although the method described above may include configuring power meter points for each of a plurality of signal chains, it will be understood that in alternative embodiments, all of the plurality of signal chains need not be configured with power meter points. In some cases, there may be a limited number of power meter points available at any given time. This means that the power meter resources can be time-shared among the plurality of signal chains. Thus, in these embodiments, signal samples may not be continuously captured for all of the plurality of signal chains. However, since the signal samples are averaged according to the RFIC and then further averaged in a time window associated with average power control, even if the time window can be 100 ms, due to the law of large numbers, a 10 ms interval on which the signal samples are captured will be acceptable.

[0053] In addition, although not shown in Figure 2 In some embodiments, the method may further include, prior to capturing a plurality of signal samples of one or more signal chains of each of one or more RFICs at step 210: capturing a calibration set of signal samples of one or more signal chains of each of one or more RFICs at the AAS and at the baseband unit, and calibrating the baseband unit based on the calibration set of signal samples. In these embodiments, the capture of the plurality of signal samples of one or more signal chains of each of one or more RFICs at step 210 may be performed at the baseband unit. In addition, the calibration set of signal samples captured at the AAS may be a highly restricted set with respect to all signal samples, and these signal samples may be used for the purpose of establishing the response / correlation between the capture points in the baseband unit and the capture points in the AAS. Once the calibration is performed, the capture of a longer signal sequence may be performed at the baseband unit, which may be beneficial in offloading the task processing at the AAS.

[0054] Although not shown in Figure 2As shown, in some embodiments, the method may further include: summing at least one subset of a plurality of signal samples to obtain a plurality of short-term average power values at the AAS; storing the plurality of short-term average power values at the AAS in a sliding time window, wherein the duration of the sliding time window is longer than the duration of capturing the plurality of short-term average power samples; and performing average power control over the duration of the sliding time window based on the stored short-term average power values. Additionally, as described above, in some embodiments, the baseband unit may further include a scheduling unit. In these embodiments, average power control may be performed by performing the following steps: obtaining a setpoint average power value at the baseband unit; determining an average power value by obtaining an average of the stored plurality of short-term average power values at the AAS; determining a difference between the setpoint average power value and the determined average power value at the baseband unit; and adjusting, at the scheduling unit, a limit associated with the amount of resources used at the AAS based on the determined difference between the setpoint average power value and the average power value.

[0055] Figure 3 is a block diagram of a network node according to an embodiment. The network node 300 is equipped with an advanced antenna system (AAS) 310, and the AAS includes a plurality of antenna elements 312-1 to 312-k and one or more radio frequency integrated circuits (RFICs) 314-1 to 314-k. In some embodiments, the network node may be a next-generation node B (gNB).

[0056] In the present embodiment, each of the one or more RFICs 314-1 to 314-k is associated with one or more of the plurality of antenna elements 312-1 to 212-k. The network node 300 further includes a processing circuit 320. In some embodiments, the AAS may further include a radio unit configured to be connected to the baseband unit through an interface. Additionally, although Figure 2 the processing circuit 320 in is shown as a single entity at the network node 300, it should be understood that the processing circuit may include: one or more processing units at the AAS level; and a plurality of processing units, each of the plurality of processing units being configured at one of the one or more RFICs 314-1 to 314-k.

[0057] Processing circuitry 320 is configured to capture a plurality of signal samples of one or more signal chains of each of the one or more RFICs, and sum at least one subset of the plurality of signal samples to obtain a short-term average power value at the AAS 310. In particular, a plurality of processing units of the processing circuitry 320 configured at each of the RFICs 314-1 to 315-k can be configured to perform the capture and summing operations. Each of the one or more signal chains corresponds to one or more of the plurality of antenna elements 312-1 to 312-k, and the signal samples are associated with the envelope power level at the output of the corresponding signal chain. At least in the context of the present disclosure, the envelope power level is understood to refer to the instantaneous RF power level averaged over one RF cycle. The determination of the short-term average power value at the AAS can be expressed in a manner similar to that proposed by Equation (4) provided above with reference to Figure 2 The manner provided by Equation (hereinafter referred to as Equation (4)) can be expressed.

[0058] In some embodiments, the processing circuitry 320 can be configured to sum at least one subset of the plurality of signal samples by performing the following steps: for each of the plurality of RFICs 314-1 to 314-k, sum at least one subset of the plurality of signal samples of each of the one or more signal chains of the corresponding RFIC to obtain a short-term average power value according to the RFIC; and sum the short-term average power values according to the plurality of RFICs to obtain the short-term average power value at the AAS 310. The determination of the short-term average power value according to the RFIC can be expressed in a manner similar to that proposed by Equation (5) provided above with reference to Figure 2 The manner provided by Equation (hereinafter referred to as Equation (5)) can be expressed.

[0059] In some embodiments, the processing circuitry 320 can be configured to capture each of the plurality of signal samples of one or more signal chains of each of the plurality of RFICs 314-1 to 314-k by performing the following steps: detect the in-phase component and the quadrature phase component of the corresponding signal; and square the in-phase component and the quadrature phase component of the corresponding signal. In these embodiments, the processing circuitry 320 can be configured to sum at least one subset of the plurality of signal samples by summing or integrating the squared in-phase components and squared quadrature components of the plurality of signal samples to obtain a power estimate representing the short-term average power value at the AAS 310. The average value of the signal samples at the signal chain can be expressed in a manner similar to that proposed by Equation (6) provided above with reference to Figure 2 The manner provided by Equation (hereinafter referred to as Equation (6)) can be expressed.

[0060] In addition, in some embodiments, the processing circuit 320 may be configured to detect the in-phase component and the quadrature-phase component of a corresponding signal by performing one of the following steps: detecting the in-phase component and the quadrature-phase component over a predetermined time period; and detecting a predetermined number of in-phase components and quadrature-phase components.

[0061] In some embodiments, the processing circuit 320 may be configured to capture a plurality of signal samples at one or more predetermined intervals. Each of the one or more predetermined intervals may have a predetermined duration. In some embodiments, the one or more predetermined intervals may be configured such that they avoid or exclude high / low power scheduling time slots so as not to introduce an undesired bias into the short-term average power value. The processing circuit 320 may also be configured to capture a plurality of signal samples at a plurality of predetermined intervals, and the time elapsed between the plurality of predetermined intervals may be based on a predetermined pattern. The predetermined pattern may be a random pattern.

[0062] The processing circuit 320 may be configured to: prior to capturing a plurality of signal samples of one or more signal chains of each of the plurality of RFICs 314-1 to 314-k, configure power meter points for each of the one or more signal chains. The power meter points may be configured to capture signal samples of the corresponding signal chains. In these embodiments, the processing circuit 320 may be configured to configure the power meter points by allocating the corresponding power meter points at relative positions along the corresponding signal chains. The relative positions allocated in the corresponding signal chains may be after the crest factor reduction (CFR) block in the corresponding signal chains.

[0063] In addition, in some embodiments, the processing circuit 320 may be configured to: prior to capturing a plurality of signal samples of one or more signal chains of each of the one or more RFICs 314-1 to 314-k: capture a calibration set of signal samples of one or more signal chains of each of the one or more RFICs 314-1 to 314-k at the radio unit and at the baseband unit; and calibrate the baseband unit based on the calibration set of signal samples. In these embodiments, the processing circuit 320 may be configured to capture a plurality of signal samples of one or more signal chains of each of the one or more RFICs 314-1 to 314-k at the baseband unit.

[0064] In some embodiments, the processing circuit 320 may be configured to: sum at least one subset of a plurality of signal samples to obtain a plurality of short-term average power values at the AAS; store the plurality of short-term average power values at the AAS in a sliding time window, wherein the duration of the sliding time window is longer than the duration of capturing the plurality of short-term average power samples; and perform average power control over the duration of the sliding time window based on the stored short-term average power values. In some of these embodiments, the baseband unit may include a scheduling unit, and the processing circuit 320 may be configured to perform average power control by performing the following steps: obtain a setpoint average power value at the baseband unit; determine an average power value by obtaining an average of the plurality of short-term average power values stored at the AAS; determine a difference between the setpoint average power value and the determined average power value at the baseband unit; and at the scheduling unit, adjust a limit associated with the amount of resources used at the AAS based on the determined difference between the setpoint average power value and the average power value.

[0065] Figure 4 An example of a feedback control mechanism for controlling average power that can be applied to embodiments of the present disclosure is shown.

[0066] In Figure 4 , represents the setpoint average power value. Generally, this setpoint average power value is slightly lower than a threshold that can be obtained based on the regulated power density and the desired compliance distance (see Table 1 above). The setpoint average power value is input to a controller (the controller may be part of the processing circuit of the network node), and then the controller outputs a control signal u(s) based on the setpoint average power value and the short-term average power value value. The short-term average power value will be explained in more detail below.

[0067] Additionally, in Figure 4 , 1 / s represents the dynamic characteristics of the actuator with a lower limit and an upper limit, where s represents the Laplace transform variable, and represents the limit of the scheduling unit after the lower limit and the upper limit (which are not active and thus not shown in Figure 4 ). represents the maximum total power of the node. w(t) represents a perturbation that brings a predicted power error. 1 / (sT + 1) represents an autoregressive reduced model of the averaging operation for determining the average total power of the node, where T represents a predetermined time period. represents the averaged short-term average power. e(s) represents the measurement error. Thus, the short-term average power value is represented as . Additionally, G represents the antenna gain. EIRP(s) represents the equivalent isotropically radiated power (EIRP).

[0068] Note that it is allowed to represent in the Laplace transform domain, i.e., to represent all quantities here with the variable s, because the feedback control mechanism design is performed under the condition that the constraints do not take effect. It should also be noted that w(s) and e(s) are only mathematical approximations in the feedback control mechanism. They can be used to evaluate the performance aspects of the embodiments of the present disclosure, but in some embodiments, they may not necessarily be part of the method disclosed herein.

[0069] Accordingly, embodiments of the present disclosure provide methods and apparatuses for measuring the average power on an RFIC near an antenna element, so as to ensure AAS deployment in cases where short-term average power measurement is required as the basis for average power control for RF exposure limit compliance.

[0070] A computer program product including a computer-readable medium is also provided. The computer-readable medium has computer-readable code included therein. The computer-readable code is configured to cause a computer or a processor to execute one or more methods described herein when executed by a suitable computer or processor. Thus, it will be understood that the present disclosure is also applicable to computer programs suitable for implementing the embodiments, particularly computer programs on or in a carrier. The program can be in the form of source code, object code, intermediate source code and object code, such as a partially compiled form, or any other form suitable for use in implementing the method according to the embodiments described herein.

[0071] It will also be understood that such a program can have many different architectural designs. For example, the program code implementing the functionality of the method or system can be subdivided into one or more subroutines. Many different ways of distributing the functionality among these subroutines will be obvious to those skilled in the art. The subroutines can be stored together in an executable file to form a self-contained program. Such an executable file can include computer-executable instructions, e.g., processor instructions and / or interpreter instructions (e.g., Java interpreter instructions). Alternatively, one or more or all of these subroutines can be stored in at least one external library file and linked to the main program statically or dynamically, e.g., at runtime. The main program contains at least one call to at least one of these subroutines. The subroutines can also include function calls to each other.

[0072] Embodiments related to a computer program product include computer-executable instructions corresponding to each processing stage of at least one of the methods set forth herein. These instructions may be subdivided into subroutines and / or stored in one or more files that may be statically or dynamically linked. Other embodiments related to a computer program product include computer-executable instructions corresponding to each component of at least one of the systems and / or products set forth herein. These instructions may be subdivided into subroutines and / or stored in one or more files that may be statically or dynamically linked.

[0073] The carrier of a computer program can be any entity or device capable of carrying the program. For example, the carrier may include a data storage device, such as a ROM (e.g., a CD ROM or a semiconductor ROM) or a magnetic recording medium (e.g., a hard disk). Additionally, the carrier can be a transmissible carrier, such as an electrical or optical signal that can be transmitted via a cable or an optical fiber or by radio or other components. When the program is embodied in such a signal, the carrier can consist of such a cable or other device or component. Alternatively, the carrier can be an integrated circuit in which the program is embedded, the integrated circuit being adapted to execute the relevant method or to be used in the execution of the relevant method.

[0074] By studying the drawings, the disclosure, and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments when practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may perform the functions of several items recited in the claims. The fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium provided together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

[0075] The foregoing disclosure sets forth specific details, such as specific embodiments or examples, for purposes of explanation and not limitation. Those skilled in the art will appreciate that other examples may be employed in addition to these specific details.

Claims

1. A method at a network node equipped with an Advanced Antenna System, AAS, wherein, The AAS includes a plurality of antenna elements and one or more radio frequency integrated circuits (RFICs), and wherein each of the one or more RFICs is associated with one or more of the plurality of antenna elements. The method includes: Capturing (210) a plurality of signal samples of one or more signal chains of each of the one or more RFICs, wherein each of the one or more signal chains corresponds to one or more of the plurality of antenna elements, and the signal samples are associated with an envelope power level at the output of the corresponding signal chain; and Summing (220) at least one subset of the plurality of signal samples to obtain a short-term average power value at the AAS, wherein summing (220) at least one subset of the plurality of signal samples includes: For each of the plurality of RFICs, summing at least one subset of the plurality of signal samples of each of the one or more signal chains of the corresponding RFIC to obtain a short-term average power value per RFIC; and Summing the short-term average power values per RFIC to obtain the short-term average power value at the AAS.

2. The method according to claim 1, Among them, Capturing (210) each of the plurality of signal samples of the one or more signal chains of each of the plurality of RFICs includes: Detecting an in-phase component and a quadrature-phase component of the corresponding signal; and Squaring the in-phase component and the quadrature-phase component of the corresponding signal, and wherein summing (220) at least one subset of the plurality of signal samples includes: summing or integrating the squared in-phase components and squared quadrature-phase components of the plurality of signal samples to obtain a power estimate representing the short-term average power value at the AAS.

3. The method according to claim 2, wherein Detecting the in-phase component and the quadrature-phase component of the corresponding signal includes one of the following: Detecting the in-phase component and the quadrature-phase component over a predetermined time period; and Detecting a predetermined number of in-phase components and quadrature-phase components.

4. The method according to any one of claims 1 to 3, wherein, Performing the capturing (210) of the plurality of signal samples at one or more predetermined intervals.

5. The method according to claim 4, wherein Each of the one or more predetermined intervals has a predetermined duration.

6. The method according to claim 4, wherein, Performing the capturing (210) of the plurality of signal samples at a plurality of predetermined intervals, and the time elapsed between the plurality of predetermined intervals is based on a predetermined pattern.

7. The method according to claim 6, wherein, The predetermined pattern is a random pattern.

8. The method according to any one of claims 1-3 further comprises: Before capturing (210) the plurality of signal samples of the one or more signal chains of each of the plurality of RFICs, configuring power meter points for each of the one or more signal chains, wherein the power meter points are configured to capture signal samples of the corresponding signal chain.

9. The method according to claim 8, wherein, Configuring the power meter points includes: allocating the corresponding power meter points at relative positions along the corresponding signal chain.

10. The method according to claim 9, wherein, The relative position allocated in the corresponding signal chain is after a crest factor reduction (CFR) block in the corresponding signal chain.

11. The method according to any one of claims 1-3, wherein, The AAS further includes a radio unit configured to be connected to the baseband unit through an interface.

12. The method according to claim 11, wherein, The method further includes, before capturing (210) the plurality of signal samples of one or more signal chains of each RFIC among the one or more RFICs: capturing a calibration set of signal samples of one or more signal chains of each RFIC among the one or more RFICs at the radio unit and at the baseband unit; and calibrating the baseband unit based on the calibration set of signal samples; wherein the capturing of the plurality of signal samples of one or more signal chains of each RFIC among the one or more RFICs is performed at the baseband unit.

13. The method according to claim 12, further comprising: summing at least one subset of the plurality of signal samples to obtain a plurality of short-term average power values at the AAS; storing the plurality of short-term average power values at the AAS in a sliding time window, wherein the duration of the sliding time window is longer than the duration of capturing the plurality of short-term average power samples; and performing average power control over the duration of the sliding time window based on the stored short-term average power values.

14. The method according to claim 13, wherein The baseband unit further includes a scheduling unit, and wherein the average power control is performed by performing the following steps: obtaining a setpoint average power value at the baseband unit; determining an average power value by obtaining an average of the plurality of short-term average power values stored at the AAS; determining a difference between the setpoint average power value and the determined average power value at the baseband unit; and adjusting, at the scheduling unit, a limit associated with the amount of resources used at the AAS based on the determined difference between the setpoint average power value and the average power value.

15. A computer program product comprising a computer-readable medium having computer-readable code embodied therein, the computer-readable code being configured to, when executed by a suitable computer or processor, cause the computer or processor to perform the method according to any one of claims 1 to 14.

16. A network node (300) equipped with an Advanced Antenna System (310) AAS, wherein, The AAS includes a plurality of antenna elements (312-1 - 312-k) and one or more radio frequency integrated circuits (314-1 - 314-k) RFICs, and wherein each RFIC among the one or more RFICs is associated with one or more of the plurality of antenna elements, wherein the network node includes a processing circuit (320), the processing circuit (320) being configured to: capture a plurality of signal samples of one or more signal chains of each RFIC among the one or more RFICs, wherein each signal chain among the one or more signal chains corresponds to one or more of the plurality of antenna elements, and the signal samples are associated with the envelope power level at the output of the corresponding signal chain; and Sum at least one subset of the plurality of signal samples to obtain a short-term average power value at the AAS, wherein the processing circuit (320) is configured to sum at least one subset of the plurality of signal samples by performing the following steps: For each RFIC of the plurality of RFICs (314-1 - 314k), sum at least one subset of the plurality of signal samples of each signal chain in the corresponding RFIC's one or more signal chains to obtain a short-term average power value per RFIC; and Sum the short-term average power values per RFIC of the plurality of RFICs to obtain a short-term average power value at the AAS (310).

17. The network node (300) according to claim 16, wherein, The processing circuit (320) is configured to capture each signal sample of the plurality of signal samples of each signal chain of each RFIC of the plurality of RFICs (314-1 - 314k) by performing the following steps: Detect the in-phase component and the quadrature-phase component of the corresponding signal; and Square the in-phase component and the quadrature-phase component of the corresponding signal, And wherein the processing circuit is configured to sum at least one subset of the plurality of signal samples by summing or integrating the squared in-phase components and squared quadrature components of the plurality of signal samples to obtain a power estimate representing the short-term average power value at the AAS (310).

18. The network node (300) according to claim 17, wherein, The processing circuit (320) is configured to detect the in-phase component and the quadrature-phase component of the corresponding signal by performing one of the following steps: Detect the in-phase component and the quadrature-phase component over a predetermined time period; and Detect a predetermined number of in-phase components and quadrature-phase components.

19. The network node (300) according to any one of claims 16 to 18, wherein, The processing circuit (320) is configured to capture the plurality of signal samples at one or more predetermined intervals.

20. The network node (300) according to claim 19, wherein, Each of the one or more predetermined intervals has a predetermined duration.

21. The network node (300) according to claim 19, wherein, The processing circuit (320) is configured to capture the plurality of signal samples at a plurality of predetermined intervals, and the time elapsed between the plurality of predetermined intervals is based on a predetermined pattern.

22. The network node (300) according to claim 21, wherein, The predetermined pattern is a random pattern.

23. The network node (300) according to any one of claims 16 to 18, wherein, The processing circuit (320) is configured to configure power meter points for each signal chain of the plurality of signal chains before capturing the plurality of signal samples of each signal chain of each RFIC of the plurality of RFICs (314-1 - 314k), wherein the power meter points are configured to capture signal samples of the corresponding signal chain.

24. The network node (300) according to claim 23, wherein, The processing circuit (320) is configured to configure the power meter points by allocating corresponding power meter points at relative positions along the corresponding signal chain.

25. The network node (300) according to claim 24, wherein, The relative positions allocated in the corresponding signal chain are after the crest factor reduction CFR block in the corresponding signal chain.

26. The network node (300) according to any one of claims 16 to 18, wherein, The AAS (310) further includes a radio unit configured to be connected to the baseband unit through an interface.

27. The network node (300) according to claim 26, wherein, The processing circuit (320) is configured to, before capturing the plurality of signal samples of one or more signal chains of each of the one or more RFICs (314-1 - 314k): Capture a calibration set of signal samples of one or more signal chains of each of the one or more RFICs at the radio unit and at the baseband unit; And Calibrate the baseband unit based on the calibration set of signal samples; Wherein, the processing circuit is configured to capture a plurality of signal samples of one or more signal chains of each of the one or more RFICs at the baseband unit.

28. The network node (300) according to claim 27, wherein, The processing circuit (320) is configured to: Sum at least one subset of the plurality of signal samples to obtain a plurality of short-term average power values at the AAS (310); Store the plurality of short-term average power values at the AAS in a sliding time window, wherein the duration of the sliding time window is longer than the duration of capturing the plurality of short-term average power samples; And Perform average power control over the duration of the sliding time window based on the stored short-term average power values.

29. The network node (300) according to claim 28, wherein, The baseband unit further includes a scheduling unit, and wherein the processing circuit (310) is configured to perform average power control by performing the following steps: Obtain a set-point average power value at the baseband unit; Determine an average power value by obtaining an average of the plurality of short-term average power values stored at the AAS; Determine the difference between the set-point average power value and the determined average power value at the baseband unit; and At the scheduling unit, adjust a limit associated with the amount of resources used at the AAS based on the determined difference between the set-point average power value and the average power value.

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