Patent Description:
A massive Multiple Input Multiple Output (MIMO) Advanced Antenna System (AAS) radio system (i.e., a radio system implementing a massive MIMO AAS) differs from a current radio system in that it uses a very large number of antennas (e.g., tens, hundreds, or thousands of antennas) that are operated fully coherently and adaptively. Most of today's radio systems use two, four, or eight antennas. Deploying many antennas coherently in a massive MIMO AAS radio system is an essential element of Fifth Generation (<NUM>) technology for the commercial mobile network.

Existing advanced antenna radio system architectures have a limitation when attempting to scale them for a massive MIMO AAS radio system. Considering an example in which the radio system is a Base Transceiver Station (BTS), as shown in <FIG>, the number of cables interconnecting the BTS, the tower mounted amplifiers, and the antennas must increase exponentially when going from a few antennas to many antennas. Similarly, if the radio system is a Remote Radio Head (RRH), the number of cables interconnecting the RRH and the antennas must increase exponentially when going from a few antennas to many antennas, as also shown in <FIG>. The number of cables needed for massive MIMO AAS when using conventional architectures becomes impractical. As also illustrated in <FIG>, one solution is to integrate subsystems together. This integration comes but at the cost of disappearing test points. In other words, when integrating subsystems together, testing and fault isolation become challenging.

Difficulty in testing and fault isolation becomes particularly problematic for a massive MIMO AAS radio system. In particular, one important aspect of a massive MIMO AAS radio system is the ability to provide accurate, narrow beamforming. To provide this beamforming, both the amplitude and phase of each antenna element are controlled. Controlling both amplitude and phase enables adjustment of side lobe levels and steering of nulls better than that which can be done by controlling only phase.

With respect to beamforming, <FIG> illustrates one example of a massive MIMO AAS radio system that utilizes beamforming. Here, general beamforming system (including both digital beamforming and analog beamforming) is implemented using a digital precoder in the digital domain for controlling both amplitude and phase and the phase shifters in analog domain for additional phase control. If there are only a few outputs (e.g., two Inverse Fourier Transform (IFFT) - Parallel to Serial (P/S) converter - Digital to Analog Converter (DAC) chains) from the digital precoder and a large number of antenna elements (e.g., <NUM>) controlled by phase shifters in the analog transmitter, the beamforming is usually referred to as analog beamforming. The main benefit of analog beamforming is that it is a low-cost beamforming solution as compared to digital beamforming. If there are a large number of outputs from the digital precoder (e.g., <NUM> IFFT-P/S-DAC chains) and a few antenna elements controlled by phase shifters, the beamforming is usually referred to as digital beamforming. The benefit of digital beamforming is that digital beamforming provides more flexibility in frequency domain resource utilization and improved overall system performance.

In digital beamforming, the operations of phase shifting and amplitude scaling for each antenna element, and summation for receiving, are done digitally. Either general-purpose Digital Signal Processors (DSPs) or dedicated beamforming chips are used. This is a more complicated and expensive system with the benefit of improved performance.

The number of connectors corresponds to the number of physical antenna ports for digital beamforming as required by the mobile system specification. In Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) specification Release (Rel-) <NUM> to Rel-<NUM>, up to eight physical antenna ports are specified, as illustrated on the left-hand side of <FIG>. In Rel-<NUM>/<NUM>, sixteen to thirty-two physical antenna ports are defined for Full Dimension MIMO (FD-MIMO). An example for Rel-<NUM> is illustrated on the right-hand side of <FIG>. A higher number of physical antennas provides more spatial multiplexing capacity (i.e., more layers) and improved beamforming gain. In practice, there is also the trend to deploy more physical antennas (e.g. <NUM>, <NUM> antenna ports) than specified in the standard to provide additional benefits of beamforming. In such a case, antenna virtualization is usually applied. With legacy base station radio hardware with the capability of beamforming of a few antennas, antenna system testing is usually carried out manually by connecting a measurement device and the radio unit through cables, one per antenna. It is done in the lab before deployment or maintained in the field following a fault alarm. For the massive MIMO AAS system with a large number of antennas, this practice of testing and maintaining for the legacy radio system is not applicable, and no extra functionality and protocol have been defined for near-real time, non-intrusive, and in-service monitoring methods.

Because precise control of both amplitude and phase is needed for beamforming, testing and fault isolation becomes even more critical in a massive MIMO AAS radio system. An issue arises in that test and fault isolation requirements are higher for a massive MIMO AAS radio system, but the ability for testing is lessened due to the integration of subsystems. Therefore, there is a need for systems and methods for testing and fault isolation that are well-suited for a massive MIMO AAS radio system.

Document <CIT> may be construed to disclose a technique in which the Equivalent Isotropic Radiated Power EIRP emitted from an array of antenna elements at an access point of a wireless communication network is controlled. The access point is configured to form one or more beams by applying a weight set for a beamforming weighting matrix to one or more signal streams in a first mode of operation. The EIRP is controlled by calibrating transmission phase and gain of a respective transmit chain for each antenna element, providing a polar radiation model for an antenna element of the array, and determining a weight set for the weighting matrix subject to a constraint that a maximum total EIRP for the one or more beams in combination in any azimuth direction is maintained within a predetermined EIRP limit. The determination is based at least on a spatial separation of the antenna elements, the polar radiation model and the calibrated transmission phase and gain of each respective transmit chain.

Document <CIT> may be construed to disclose a method and device for detecting and repairing a channel anomaly of an active antenna. The method includes: an operation state of a transmission channel or a reception channel is determined by analyzing in real time data of a feedback coupling channel or data of the reception channel, if the operation state is anomalous, an anomaly protection is performed and an alarm is reported; a level of the alarm and a reason causing the alarm are determined, if data of the transmission/reception channel are anomalous and the anomaly protection is performed, a current antenna beam forming parameter is stored and the antenna beam forming parameter is set to zero; after the alarm has been eliminated, a stored valid antenna beam forming parameter is set to a valid value; and if a transmission/reception analog channel operates anomalously and the anomaly protection is performed, the antenna beam forming parameter is re-acquired and an acquired valid antenna beam forming parameter is configured. The present disclosure can detect states of multiple transmission/reception channels of an active antenna without an extra calibration channel, thus reducing the design cost of a system.

Document <CIT> may be construed to disclose a radio network node and a method in the radio network node, for calibration of wireless signals communicated in antenna streams with a user equipment in a wireless communication system. The radio network node comprises a multiple antenna array configured for MIMO. The method comprises receiving an uplink wireless signal, assuming the received signal to comprise a calibration error, calculating a compensation factor, compensating the received signal for the assumed calibration error, and compensating the received signal, based on the calculated compensation factor.

According to the disclosure, there are provided a method, a computer-readable medium and a radio system according to the independent claims. Developments are set forth in the dependent claims.

Systems and methods related to monitoring a status, or health, of a (e.g., massive) Multiple Input Multiple Output (MIMO) transceiver and, in particular, that of an antenna system (e.g., an Advanced Antenna System (AAS)) of the MIMO transceiver are disclosed.

Hereinabove and in the following, "examples" denote principles underlying the claimed subject-matter and/or being useful for understanding the claimed subject-matter, "embodiments" pertain to the claimed subject-matter within the claim scope and "unclaimed examples" pertain to implementations not comprised in the claim scope.

Wireless Device: As used herein, a "wireless device" refers to a device capable, configured, arranged, and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term wireless device may be used interchangeably herein with User Equipment device (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In an unclaimed example, a wireless device may be configured to transmit and/or receive information without direct human interaction. For instance, a wireless device may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in
response to requests from the network. Examples of a wireless device include, but are not limited to, a smart phone, a mobile phone, a cell phone, a Voice over Internet Protocol (IP) (VoIP) phone, a wireless local loop phone, a desktop computer, a Personal Digital Assistant (PDA), a wireless camera, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, Laptop Embedded Equipment (LEE), Laptop Mounted Equipment (LME), a smart device, a wireless Customer Premise Equipment (CPE), a vehicle mounted wireless terminal device, etc.. A wireless device may support Device-to-Device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-Everything (V2X), and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (loT) scenario, a wireless device may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another wireless device and/or a network node. The wireless device may in this case be a Machine-to-Machine (M2M) device, which may in a 3GPP context be referred to as a Machine Type Communication (MTC) device. As one particular example, the wireless device may be a UE implementing the 3GPP Narrowband loT (NB-loT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, home or personal appliances (e.g., refrigerators, televisions, etc.), or personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a wireless device may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A wireless device as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a wireless device as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

In particular, a network node refers to equipment capable, configured, arranged, and/or operable to communicate directly or indirectly with a wireless device and/or with other network nodes or equipment in the wireless network to enable and/or provide wireless access to the wireless device and/or to perform other functions (e.g., administration) in the wireless network. Examples of network nodes include, but are not limited to, Access Points (APs) (e.g., radio APs) and base stations (e.g., radio base stations, Node Bs, eNBs, and gNBs). A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or Remote Radio Units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such RRUs may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a Distributed Antenna System (DAS). Yet further examples of network nodes include Multi-Standard Radio (MSR) equipment such as MSR base stations, network controllers such as Radio Network Controllers (RNCs) or Base Station Controllers (BSCs), Base Transceiver Stations (BTSs), transmission points, transmission nodes, Multi-Cell/Multicast Coordination Entities (MCEs), core network nodes (e.g., Mobile Switching Centers (MSCs), MMEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Center (E-SMLCs)), and/or Minimization of Drive Tests (MDTs).

Existing solutions for testing and fault detection in an Advanced Antenna System (AAS) are not scalable for a massive Multiple Input Multiple Output (MIMO) AAS. In other words, existing testing methods and equipment are not able to provide the testing capability needed for a massive MIMO AAS. In particular, existing testing methods and equipment to not provide the capability to test a large number of beams radiated out of a massive MIMO AAS with a large number of ports accessible to a digital unit.

Note that AAS may interchangeably be referred to as an Advanced Antenna System, an Active Antenna System, or an Antenna Array System. For this disclosure, the term Advanced Antenna System is used.

For legacy radio systems, the antenna radiating pattern is assumed to be omni-directional and tuned at the factory, and the number of physical antenna ports is limited. Chamber based measurements are used for legacy radio systems. However, such chamber based measurements are not scalable for a massive MIMO AAS radio system due to the cost of having an exponential increase in the number of observation devices and the extra distance needed to obtain beamforming far-field measurements (e.g., n > nf = L<NUM>/2λ, where L is the height or width of the antenna array, λ is the wavelength, and n is distance of the observation point from the antenna array), without which the measurement granularity and accuracy is not sufficient. Also, failure of an individual antenna branch may or may not cause significant measurable impacts on the beamforming and MIMO capability that need to be provided by the massive MIMO AAS radio system since, for example, not all beams may be used by the massive MIMO AAS radio system. Also, for legacy radio systems, road testing is used for radiated signal measurement. However, road testing is not practical for beam profiling for a massive MIMO AAS radio system, especially for beams in both horizontal and vertical directions.

Legacy radio systems also lack continuous supervision (i.e., monitoring). After deployment, the wellness of a massive MIMO AAS radio system, and in particular the wellness of the massive MIMO AAS, needs to be continuously monitored. A legacy radio system might only be monitored, occasionally or with relatively long periodicity, by a few key characteristics (i.e., installation, power supply). Conversely, a massive MIMO AAS radio system needs to be continuously monitored because its beamforming performance depends on the wellness of each antenna element and how the antenna elements are working together cooperatively to provide the desired beamforming. For some cases, a relatively narrow beam is desired to point to a certain direction (e.g., a particular floor of a building). A particular beam is formed by a certain set of spatially coherent antennas. Malfunction of any single antenna might have a limited impact on the overall functioning of the antenna system, but might have a huge impact on a particular beam. Further, the external physical environment might impact the antenna performance, especially for millimeter wave (mmW). Radio systems using mmW have very large path loss due to tree leaves, heavy rain, or some blockage materials. The blockage might happen gradually (i.e., growing trees or a new building development), or by accident (e.g., a falling tree in front of the antenna). Note that <NUM> and mmW will likely be deployed in urban areas where, e.g., new building developments are likely to occur. Another situation is an indoor environment in which walls may be taken down or added.

Systems and methods are disclosed herein that relate to continuous supervision, or monitoring, of a MIMO transceiver (e.g., a massive MIMO transceiver or radio system implementing an AAS). In an example, internal radio component based supervision is performed. In an example, the internal radio component based supervision uses a test fixture or baseband unit as a test signal source and test signal sink. In an example, the MIMO transceiver is implemented in a radio unit of a radio access node of a wireless communication system (e.g., a 3GPP <NUM> NR system), and the internal radio component based supervision is performed preferably at the factory and periodically by a baseband unit of the radio access node on-site. While many of the examples focus on AAS, they are not limited to AAS. For example, certain examples are applicable to passive antennas.

In an example, external over-the-air based supervision is additionally or alternatively performed. In an example, the MIMO transceiver is a (e.g., massive) MIMO transceiver that includes a (e.g., massive) MIMO AAS and is implemented in a radio unit of a radio access node of a wireless communication system (e.g., a 3GPP <NUM> NR system). Further, in an unclaimed example, one or more mobile wireless devices and one or more fixed or mounted wirelines devices, and/or, in an embodiment, one or more other radio access nodes are used to perform external over-the-air based supervision in order to, e.g., validate beamforming functionality of the (e.g., massive) MIMO AAS of the transceiver.

Before describing embodiments of the present disclosure, it is beneficial to describe an example of a radio system <NUM> illustrated in <FIG> that incorporates a (e.g., massive) MIMO AAS in accordance with an example of the present disclosure. The radio system <NUM> is also referred to herein as a MIMO transceiver. As illustrated, the radio system <NUM> includes precoding circuitry <NUM> that precodes a number of input signals for multiple MIMO layers to provide a number of transmit signals to be transmitted via respective antenna branches. The radio system <NUM> includes multiple radio transceiver chains <NUM>, only one of which is illustrated in detail. There is one radio transceiver chain <NUM> for each antenna element. Each radio transceiver chain <NUM> includes a transmit path and a receive path. The transmit path includes modulation circuitry <NUM> that performs Orthogonal Frequency Division Multiplexing (OFDM) modulation of a respective transmit signal output by the precoding circuitry <NUM> and a Digital Front End (DFE) <NUM> that processes the modulated transmit signal output by the modulation circuitry <NUM>. The transmit path further includes a transmitter <NUM> that processes the transmit signal output by the DFE <NUM> to perform various transmit operations such as, e.g., digital to analog conversion, upconversion, and filtering, a power amplifier <NUM> that amplifies the Radio Frequency (RF) transmit signal and a transmit filter <NUM> that filters the amplified RF transmit signal prior to transmission via a respective antenna element <NUM>. Each radio transceiver chain also includes a receive path that includes a receive filter <NUM> that receives a signal via the antenna element <NUM>, a Low Noise Amplifier (LNA) <NUM> that amplifies the received signal, a main receiver <NUM> that processes the received signal (e.g., filtering, downconversion, and analog to digital conversion) to provide a digital receive signal that is then processed by the DFE <NUM>. In addition, the radio transceiver chain includes a transmit observation path that includes a coupler <NUM>, an attenuator <NUM>, and an observation receiver <NUM>.

The example radio system <NUM> also includes transmit circuitry <NUM> configured to inject a test signal into the transmit paths of the radio transceiver chains <NUM> via switching circuitry <NUM> and a combiner/splitter <NUM>. The combiner/splitter <NUM> is to accommodate RX and TX signals for, e.g., calibration. The radio system <NUM> also includes receive circuitry <NUM> configured to receive a signal(s) from the radio transceiver chain(s) <NUM> via the switching circuitry <NUM> and the combiner/splitter <NUM>.

The radio system <NUM> has multiple observation points (A through E) that can be used by a monitoring system. Observation point A is the Transmit Observation Receiver (TOR) feedback path used for, e.g., Digital Predistortion (DPD) adaptation to compensate for the non-linearity of the power amplifier <NUM>. Observation point B is the antenna calibration coupler. Observation point C is an over-the-air observation point. Observation point D is an uplink traffic receiver. Observation point E is an antenna calibration RF combiner output splitter input. Observation points B and E may be used for, e.g., antenna calibration.

In an example, one or more of the observation points A through E are reused for continuous monitoring of the radio system <NUM>. For example, one or more of these observation points can be reused together with one or more test vector signals to monitor the radio system <NUM> by, e.g., comparing signals at the observation point(s) to reference values while injecting a test vector signal into the radio system <NUM>. This may be beneficial to combat the challenge of sanitizing software code towards the correct behavior in the massive MIMO and beamforming domain (i.e., ensuring RF performance remains compliant, e.g., with government regulations after a new software upgrade is applied). This improvement can be applied in manufactory plants for hardware related tests. More importantly, during radio installation phase and in-service time, the internal component based supervision capabilities within each radio access node and between radio access nodes can be enabled to fulfill more precise supervision and to detect problems in the massive MIMO and beamforming areas, both before a site is put into service or during in-service.

<FIG> illustrates a radio system <NUM> according to an embodiment of the present disclosure. As illustrated, the radio system <NUM> includes a massive MIMO transceiver <NUM> and a massive MIMO radio validator <NUM>. Here, the massive MIMO transceiver <NUM> is a Device-Under-Test (DUT), and the massive MIMO radio validator <NUM> performs continuous internal and/or over-the-air supervision of the MIMO transceiver <NUM>. The massive MIMO radio validator <NUM> is preferably implemented in a digital unit of the radio system <NUM>. For example, in an embodiment, the radio system <NUM> is a radio access node (e.g., a base station) in a wireless communication system (e.g., a <NUM> NR system), where the massive MIMO transceiver <NUM> is implemented in a radio unit of the radio access node and the massive MIMO radio validator <NUM> is implemented within a digital unit of the radio access node. The massive MIMO radio validator <NUM> is implemented in hardware or a combination of hardware and software (e.g., one or more processing circuitries such as, e.g., one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Field Programmable Gate Arrays (FPGAs), and/or the like, or any combination thereof).

The massive MIMO transceiver <NUM> includes a number of radio transceiver chains <NUM>-<NUM> through <NUM>-N (generally referred to herein as radio transceiver chains <NUM>). The radio transceiver chains <NUM>-<NUM> through <NUM>-N are coupled to respective antenna elements <NUM>-<NUM> through <NUM>-N (generally referred to herein as antenna elements <NUM>). Preferably, N is a value that is relatively large, e.g., ≥ <NUM>, ≥ <NUM>, ≥ <NUM>, or ≥ <NUM>. Looking at the radio transceiver chain <NUM>-<NUM> as an example, each radio transceiver chain <NUM> includes, in this example, a DFE <NUM>, a transmitter <NUM>, a receiver <NUM>, and a coupler subsystem <NUM> interconnecting the transmitter <NUM> and the receiver <NUM> to the respective antenna element <NUM>. In this example, the coupler subsystem <NUM> includes a coupler <NUM> and switching circuitry <NUM>.

In addition, the massive MIMO transceiver <NUM> includes a test interface <NUM> that provides an interface between various observation points and, optionally, signal injection points within the radio transceiver chains <NUM> and the massive MIMO radio validator <NUM>. In this example, the observation points include observation points within the DFEs <NUM> of the radio transceiver chains <NUM>, observation points within the transmitters <NUM> of the radio transceiver chains <NUM>, observation points within the receivers <NUM> of the radio transceiver chains <NUM>, and observation points at the antenna elements <NUM>, which in this example are located in the switching circuitry <NUM>. In this example, the signal injection points include injection points into the receive paths of the radio transceiver chains <NUM>, which in this example are located within the switching circuitry <NUM>. The test interface <NUM> also includes a control interface that enables the massive MIMO radio validator <NUM> to control the switching circuitry <NUM> in the radio transceiver chains <NUM> to, e.g., either inject a signal into the receive paths, monitor the signals at the antenna port of the coupler <NUM>, or enable normal operation by coupling the antenna port of the couplers <NUM> to the respective antenna elements <NUM>. The observation points are along the path including the DFE <NUM>, the transmitter <NUM>, and the receiver <NUM>. Note that when a test signal is used, the signal at a particular observation point is no longer the test signal but some transformed version of the test signal.

<FIG> is a flow chart that illustrates the operation of the massive MIMO radio validator <NUM> of <FIG> according to an embodiment of the present disclosure. For this discussion, the radio system <NUM> is a radio access node (e.g., a base station), where the massive MIMO transceiver <NUM> is implemented in a radio unit of the radio access node and the massive MIMO radio validator <NUM> is implemented in a digital unit of the radio access node. As illustrated, the massive MIMO radio validator <NUM> calibrates the antenna elements <NUM> and the radio transceiver chains <NUM> of the massive MIMO transceiver <NUM> during commissioning of the radio system <NUM> (step <NUM>). In an embodiment, the radio system <NUM> is part of a radio access node (e.g., a base station), and step <NUM> is performed at the time of commissioning, i.e., when installing the radio unit of the radio access node at a particular site. Note that a particular radio access node (e.g., a base station) may have or be connected to multiple radio systems <NUM>, wherein this process is performed for each of those radio systems <NUM>.

More specifically, as of the practice today, the radio unit including the massive MIMO transceiver <NUM> is subject to calibration in the factory using, e.g., a test fixture with a set of predefined input. The goal is that, after calibration, the radio unit will not deviate outside the tolerance of a defined performance specification. In other words, some level of uniformity can be achieved across batches of radio units heading to respective installation sites.

Step <NUM> enhances the on-site installation procedure. In particular, today, a radio system performs a self-test at start-up. However, this legacy approach is insufficient for the massive MIMO transceiver <NUM> because successful digital beamforming requires the baseband unit as well. Thus, during the installation phase or on-site installation, the massive MIMO radio validator <NUM>, which is implemented in the baseband unit of the radio system <NUM>, emits test signals. Together with the massive MIMO transceiver <NUM> in the radio unit of the radio system <NUM>, the massive MIMO radio validator <NUM> performs test procedures. In this regard, the baseband unit acts like the test fixture in the factory and must take part in the validation using calibration reference values obtained from the factory.

This one-time on-site recalibration is beneficial. Typically, new software is applied to the radio system <NUM> since it left the factory, and the hardware has been subjected to transportation. It also confirms the on-site installation, such as cabling, is correct. The objective is to ensure that the radio system <NUM> works as desired to support beamforming and MIMO functionalities.

It should be noted that the antenna elements <NUM> may not be connected to the massive MIMO transceiver <NUM> at this stage. This is typically a preparation phase before over-the-air radiation is allowed.

This on-site calibration procedure <NUM> can be triggered in many ways. For example, on initial power-up, the on-site calibration procedure <NUM> can be triggered autonomously and/or automatically and/or manually or by a special command, a test button (or switch), or the like.

The massive MIMO radio validator <NUM> obtains first measurements and saves these first measurements as reference values (step <NUM>). The first measurements include measurements performed for internal radio component based supervision and/or measurements performed for over-the-air based supervision. More specifically, in an example, the massive MIMO radio validator <NUM> provides test signals to the radio transceiver chains <NUM> of the massive MIMO transceiver <NUM>. These test signals may include test signals input to the radio transceiver chains <NUM> as transmit signals to be transmitted via the transmit paths of the radio transceiver chains <NUM> and/or test signals injected into the receive paths of the radio transceiver chains <NUM> via the switching circuitry <NUM> of the radio transceiver chains <NUM>. While these test signals are being provided to the radio transceiver chains <NUM>, measurements are obtained from one or more of the observations points for one or more, and preferably all, of the radio transceiver chains <NUM>. These measurements are the first measurements that are stored as reference values.

In a similar manner, first measurements to be used for reference values for over-the-air based supervision may be obtained. In an unclaimed example, test signals are transmitted by the radio system <NUM> and measured by wireless devices mounted to a mobile or stationary test fixture and/or measured by another radio access node(s). In an embodiment, test signals are transmitted by wireless devices mounted to a mobile or stationary test fixture and/or transmitted by another radio access node(s) are measured by the radio system <NUM>. These measurements are then stored as reference values.

In an embodiment, step <NUM> is performed the first time that the radio unit of the radio system <NUM> is connected to the antenna elements <NUM> and the radio access node is placed into service. Thus, the first measurements establish the initial measurements as the radio system <NUM> is deployed and in operation.

Here, the first measurements are stored as reference values that reflect the actual radio status in the actual deployment environment where internal radio component settings are tuned to the specific site location based on network planning. The measurements at the installation phase are a calibration to the standard environment and radio component settings. For example, the antenna elements <NUM> may be under the shadow of a tall building, and this will be collected and archived as a reference.

As stated above, the first measurements are stored, e.g., locally in the radio system <NUM> and/or remotely at a central processing unit. The first measurement results are kept as the reference values, e.g., until re-calibration is performed at which time the reference values are updated. At the same time, each parameter has a pre-set threshold for the measurement variation associated with the calibrated value. If any of the first measurements fall outside of the pre-set threshold range, warnings can be generated to the operator right away and, therefore, problems can be corrected before the operator leaves the site.

In an example, the measurements from all monitoring categories are carried out during this phase. Further, in an example, a timer of each measurement and a timer of the corresponding reporting are set to desired values at the completion of step <NUM>. Note that a single supervision timer may be used or multiple supervision timers may be used for different categories of measurements.

In an example, the massive MIMO radio validator <NUM> then performs continuous monitoring of the massive MIMO transceiver <NUM> (step <NUM>). This continuous monitoring includes continuous internal radio component based supervision (step 604A) and/or continuous over-the-air based supervision (step 604B).

With respect to the internal radio component based supervision, the massive MIMO radio validator <NUM> again provides the known test signals to the radio transceiver chains <NUM> of the massive MIMO transceiver <NUM> and obtains measurements from one or more of the observation points for the radio transceiver chains <NUM> (via the test interface <NUM>). Here, the test signals are preferably the same as those used to obtain the reference measurements. These measurements can be compared to the stored reference values to determine the status, or health, of the massive MIMO transceiver <NUM>, as described below.

The internal radio component based supervision is used to periodically collect measurements that, when compared to corresponding reference values, are indicative of the status of the massive MIMO transceiver <NUM>. The internal radio component based supervision, and in particular the measurements collected via the internal radio component based supervision, can be performed as frequently as needed or desired. For instance, the internal radio component based supervision may be performed as frequently as, e.g., antenna calibration to monitor the health of the transmit and receive paths. As discussed below, if the collected measurements differ from the corresponding reference values by more than a predefined threshold amount, the massive MIMO radio validator <NUM> reports an error to, e.g., an operator (user) and/or another system component such as, e.g., a fault handling process. One or more actions may be taken in response to the indication of the error such as, e.g., adjusting the beamforming method to adapt to the fault before the fix or replacement (e.g., by using a new beamforming pattern or otherwise compensating for the fault), or declaring a radio hardware fault for replacement.

With respect to over-the-air supervision, the massive MIMO radio validator <NUM> operates to perform one or more over-the-air supervision procedures that work together with one or more wireless devices and/or one or more other radio access nodes to determine the status of the massive MIMO transceiver <NUM>. In an example, the external over-the-air supervision obtains periodic measurements using one or more wireless devices and/or one or more other radio access nodes to determine whether the performance of the massive MIMO transceiver <NUM> satisfies one or more predefined conditions. In an example, the over-the-air supervision is performed during quiet times, e.g., during night-time hours or during a maintenance window. In an unclaimed example, when the measurements for over-the-air supervision are performed, test signals are transmitted by the radio system <NUM> and measured by wireless devices mounted to a selected mobile or stationary test fixture and/or measured by another radio access node(s). Measurements made with respect to the selected mobile or stationary test structure are repeatable. In an example, test signals transmitted by wireless devices mounted to a mobile or stationary test fixture and/or transmitted by another radio access node(s) are measured by the radio system <NUM>. These measurements are then used to determine a status of the massive MIMO transceiver <NUM> by, e.g., comparing the measurements to a stored reference value. In an example, an existing digital beam tilting capability of the radio access node is used during testing to facilitate more targeted testing (e.g., to point to a specific portion of the antenna array of the in-test radio access node). Additional details of embodiments and (unclaimed) examples of the over-the-air supervision are described below.

At some point, the massive MIMO radio validator <NUM> determines a health, or status, of the massive MIMO transceiver <NUM> and, in particular, the antenna element <NUM> based on the measurements collected in step <NUM> (step <NUM>). For example, a timer may be used. The supervision of step <NUM> is performed as long as the timer has not expired. Once the timer has expired, the massive MIMO radio validator <NUM> determines the health of the massive MIMO transceiver <NUM> based on the collected measurements. In an example, the collected measurements are compared to the reference measurements obtained in step <NUM>. If the collected measurements do not deviate from the reference values by more than a predefined amount, the massive MIMO transceiver <NUM> is determined to be healthy. However, if any of the collected measurements do deviate from the reference values by more than a predefined amount, the massive MIMO transceiver <NUM> is determined to be non-healthy. Note that as used herein "non-healthy" means that there is an abnormality, where this abnormality may be due to a hardware fault in the massive MIMO transceiver <NUM> or a change in environmental conditions (e.g., a new obstruction).

If the status of the massive MIMO transceiver <NUM> is non-healthy (i.e., if the health is determined to not be normal) (step <NUM>, NO), then the massive MIMO radio validator <NUM> initiates one or more actions to correct this error (step <NUM>). For example, the massive MIMO radio validator <NUM> may inform an operator of the error and/or inform another system component that is responsible for fault correction of the error. The action(s) taken to the correct this error may be, for example, adjusting the beamforming method to adapt to the fault before the fix or replacement (e.g., by using a new beamforming pattern or otherwise compensating for the fault), or declaring a radio hardware fault for replacement. If the status of the massive MIMO transceiver <NUM> is healthy (i.e., if the health is determined to be normal) (step <NUM>, YES), then the massive MIMO radio validator <NUM> re-calibrates the reference values using the measurements obtained in step <NUM>, if needed or otherwise desired (step <NUM>). Whether proceeding from step <NUM> or <NUM>, the process then returns to step <NUM> and is repeated.

Note that, in an example, the radio system <NUM> is able to recover, or at least attempt to recover, from a detected error by an autonomous action(s). In particular, when the supervision detects an error, a fault handling process decides whether to (a) continue operation with a modified beamforming or MIMO strategy with re-calibration or (b) take some other action(s) such as restarting the massive MIMO transceiver <NUM> or requesting that an operator replace the massive MIMO transceiver <NUM> by alerting the operator of the error.

<FIG> illustrates the massive MIMO radio validator <NUM> in more detail according to an example. As illustrated, the massive MIMO radio validator <NUM> includes a test vector bank <NUM> that stores one or more test signal vectors that are input to the radio transceiver chains <NUM> during testing, a signal generator <NUM> that generates a signal injected into the receive paths of the radio transceiver chains <NUM> during testing, a signal analyzer <NUM> that obtains measurements from signals obtained from the test interface <NUM> for one or more observation points in the radio transceiver chains <NUM>, a correlation engine <NUM> that compares the obtained measurements to corresponding reference values to detect the health of the massive MIMO transceiver <NUM>, and a controller <NUM> that provides control for the testing of the massive MIMO transceiver <NUM>. For instance, the controller <NUM> controls the various components of the massive MIMO radio validator <NUM> and the switching circuitry <NUM> of the radio transceiver chains <NUM> to obtain the reference measurements and to perform monitoring of the massive MIMO transceiver <NUM> as described herein.

<FIG> illustrates steps <NUM> through <NUM> of <FIG> in more detail in accordance with an unclaimed example. This discussion is particularly directed to internal component based supervision being performed; however, a similar process may be performed for over-the-air based supervision. As illustrated, in order to obtain the first measurements that are stored as the reference values, the massive MIMO radio validator <NUM> obtains reference measurements for one or more observation points within each of at least a subset of the radio transceiver chains <NUM> of the massive MIMO transceiver <NUM> for each of multiple transmit and/or receive beam directions (step <NUM>). These reference values are stored locally at the radio system <NUM> and/or stored remotely. Alternatively, the reference values are general reference values stored at the radio system <NUM> or obtained from another node. In other words, step <NUM> may not be performed; rather, the reference values are general reference values that are stored at the radio node <NUM>, e.g., during manufacturing or obtained from another node.

In order to perform continuous internal component based supervision of the massive MIMO transceiver <NUM> during operation, the massive MIMO radio validator <NUM> obtains test measurements for the one or more observation points within each of the at least a subset of the radio transceiver chains <NUM> of the massive MIMO transceiver <NUM> for each of the multiple transmit and/or receive beam directions (step <NUM>).

More specifically, in an unclaimed example, the massive MIMO radio validator <NUM> transmits a known test signal on a transmit beam via the transmit paths of the radio transceiver chains <NUM> (step 802A-<NUM>). In an unclaimed example, the known signal transmitted on the transmit beam is the same as that transmitted via the transmit paths of the radio transceiver chains <NUM> while obtaining the respective reference measurements for the transmit beam, or a derivative thereof. While transmitting this known test signal, the massive MIMO radio validator <NUM> obtains a test measurement(s) for at least one observation point in each of at least a subset of the radio transceiver chains <NUM> (step 802A-<NUM>). The massive MIMO radio validator <NUM> repeats steps 802A-<NUM> and 802A-<NUM> for one or more additional transmit beam directions (step 802A-<NUM>).

In an unclaimed example, the massive MIMO radio validator <NUM> injects a known test signal on a receive beam via the receive paths of the radio transceiver chains <NUM> (step 802B-<NUM>). In an unclaimed example, the known signal injected on the receive beam is the same as that injected into the receiver paths of the radio transceiver chains <NUM> while obtaining the respective reference measurements for the receive beam, or a derivative thereof. While injecting this known test signal, the massive MIMO radio validator <NUM> obtains a test measurement(s) for at least one observation point in each of at least a subset of the radio transceiver chains <NUM> (step 802B-<NUM>). The massive MIMO radio validator <NUM> repeats steps 802B-<NUM> and 802B-<NUM> for one or more additional receive beam directions (step 802B-<NUM>).

The massive MIMO radio validator <NUM> then determines the health of the massive MIMO transceiver <NUM> based on a comparison of the test measurements and the corresponding reference measurements (step <NUM>), as described above.

<FIG> provide additional details for (unclaimed) examples and embodiments of over-the-air based supervision. In particular, <FIG> illustrates an unclaimed example of a non-network-assisted over-the-air based supervision of the massive MIMO transceiver <NUM> of the radio system <NUM> where, in this example, the radio system <NUM> is again a radio access node in which the massive MIMO transceiver <NUM> is implemented in a radio unit of the radio access node and the massive MIMO radio validator <NUM> is implemented in a digital unit of the radio access node. In this example, non-network-assisted over-the-air supervision is performed to obtain information that is indicative of a beam directivity of the massive MIMO transceiver <NUM>. In other words, information is obtained that is indicative of the main lobe width (Φ). Main lobe width is the selectivity of the main lobe transmission measured as the degree azimuth spread across the main lobe. As illustrated, multiple wireless devices (referred to as UEs A, B, C, D, and E) are mounted on a stationary or mobile test structure. In this example, the wireless devices operate signal generators. In operation, UEs A, B, C, D, and E each transmit a signal (e.g., Sounding Reference Signal (SRS)) preferably at the same transmit power. The radio access node, and in particular the radio system <NUM> of the radio access node, measures a received power for each of the signals. Initially, this may be done to obtain reference measurements, as described above. Subsequently, in an example, these measurements are repeated and compared to the reference measurements to monitor the health of the massive MIMO transceiver <NUM> of the radio access node. For example, if the reference measurements show that the receive power of UE A should be substantially greater than that from each of the other UEs but the test measurements show that the receive power of UE A is not substantially greater than that from each of the other UEs, then the health of the massive MIMO transceiver <NUM> is determined to be non-healthy. Note that, as used herein, "receive power" and "receive power measurement" refer to any type of measurement that is a function of the receive power (e.g., actual receive power, received signal strength, Signal to Interference plus Noise Ratio (SINR), or the like). Alternatively, there may be no reference measurements, and the receive beam is known to be directed at UE A. If the massive MIMO transceiver <NUM> has good directivity, the signal from UE A is expected to be the strongest signal received assuming that all of the UEs transmit at the same calibrated power level. This is shown as the left sub-diagram. However, if the antenna directivity towards UE A is not as expected, the other UEs will also be seen to have strong signals also. In other words, the signal isolation coming from antenna directivity may require further investigation. This is an indication of a non-healthy status of the massive MIMO transceiver <NUM>.

Note that <FIG> illustrates both stationary test structures (e.g., test structures affixed to a building or street light) and mobile test structures (e.g., test structures affixed to a drone or automobile). The mobile test structure can be affixed to a drone (or multiple drones) with known Global Positioning System (GPS) coordinates. The mobile test structure may also be affixed to a road test vehicle. Periodic measurements can be conducted over time using the mobile and/or stationary test structures to confirm environmental changes are captured.

The use of test structures simultaneously can also be possible and not exclusive. For example, if the antenna beam is formed towards the test structure affixed to the roof of the building, the massive MIMO transceiver <NUM> may also detect signals transmitted by the wireless devices mounted on the test structure affixed to the nearby street light. This additional data may be used to help measure the main lobe width.

A variation can make use of a wireless device <NUM> at the cell edge, as illustrated in <FIG>. In an example, a dedicated wireless device <NUM> is carefully placed at the cell edge between two or more radio access nodes <NUM> and <NUM> that are simultaneously connected to the wireless device <NUM>. The radio access nodes <NUM> and <NUM>, which can each include the radio system <NUM> of <FIG>, listen to a beacon transmitted by the wireless device <NUM>. If one radio access node <NUM> suddenly receives the beacon with a weaker signal strength as compared to a reference measurement but the other radio access node(s) <NUM> do not, the health of the massive MIMO transceiver <NUM> of that radio access node <NUM> may be determined to be non-healthy. The wireless device <NUM> transmitting the beacon can be an ordinary UE or a special transmitter that transmits during a downlink subframe of a Time Division Duplexing (TDD) network. Since the uplink is not used for traffic, and it can be available for calibration. In other words, the downlink of the radio access node <NUM>, <NUM> forms a beam towards a UE <NUM> in service. The radio access node <NUM>, <NUM> controls the scheduler and can free up a group of subcarriers. This is a downlink subframe, and the receiver chain of the transceiver is free for use. A special UE <NUM> can transmit in contrast to an ordinary listening UE. Note that, when a subcarrier is unused, there is no interference. The receiver chain performs the calibration. Since there are observation point(s) at the antenna, these subcarriers can be extracted by filtering. In an example, when the massive MIMO transceiver <NUM> is healthy, the cell edge may be re-defined based on the beacon signal from the wireless device.

<FIG> is a flow chart that illustrates steps 604B and <NUM> of <FIG> in more detail in accordance with an unclaimed example of non-network assisted over-the-air supervision. As illustrated, the massive MIMO radio validator <NUM> obtains receive power measurements for signals received from two or more wireless devices fixed to a stationary or mobile test structure while the massive MIMO transceiver <NUM> is configured to receive on a receive beam directed to a first wireless device of the two or more wireless devices (step <NUM>). The massive MIMO radio validator <NUM> determines the status, or health, of the massive MIMO transceiver <NUM> based a comparison of the receive power for the signal received from the first wireless device and the received power for the signal received from each of the other wireless devices (step <NUM>), as described above.

<FIG> illustrates step <NUM> of <FIG> in more detail according to the unclaimed example. As illustrated, the massive MIMO radio validator <NUM> determines whether the received power for the signal received from the first wireless device (referred to here as UE A) is much greater than that of the signals received from the other wireless devices in the test structure (step <NUM>). Note that, in an unclaimed example, wireless devices for which the measurements of receive power are performed all transmit at the same transmit power. However, in another unclaimed example, the wireless devices may transmit at different transmit powers, and the receiver power measurements are normalized receiver power measurements (i.e., receiver power measurements that are normalized with respect to transmit power). Here, the received power for the signal received from the first wireless device is much greater than that of the signals received from the other wireless devices if it is greater than the received power of the signals from the other wireless devices by a predetermined amount. This predetermined amount may be determined based on reference measurements for the received power of the signals from the same wireless devices. If so, the massive MIMO radio validator <NUM> determines that the massive MIMO transceiver <NUM> is healthy (step <NUM>). Otherwise, the massive MIMO radio validator <NUM> determines that the massive MIMO transceiver <NUM> is non-healthy (step <NUM>). Note that, if the massive MIMO transceiver <NUM> is determined to be non-healthy, the massive MIMO radio validator <NUM>, an operator, or some other system component may further investigate to determine whether the non-healthy status is due to, e.g., a hardware fault in the massive MIMO transceiver <NUM> or due to environmental conditions. Environmental conditions may be checked in person by an operator or by dedicated equipment such as, e.g., a post-mounted camera.

<FIG> is a flow chart that illustrates steps 604B and <NUM> of <FIG> in more detail in accordance with an unclaimed example of non-network assisted over-the-air supervision. As illustrated, the massive MIMO radio validator <NUM> transmits a signal to a first wireless device of two or more wireless devices fixed to a stationary or mobile test structure while the massive MIMO transceiver <NUM> is configured to transmit on a transmit beam directed to the first wireless device (step <NUM>). The massive MIMO radio validator <NUM> obtains (e.g., from the wireless devices) measurements of the received power of the signal at each of the wireless devices in the test structure (step <NUM>). The massive MIMO radio validator <NUM> then determines the status, or health, of the massive MIMO transceiver <NUM> based a comparison of the receive power for the signal at the first wireless device and the received power for the signal at each of the other wireless devices (step <NUM>).

<FIG> illustrates step <NUM> of <FIG> in more detail according to the unclaimed example. As illustrated, the massive MIMO radio validator <NUM> determines whether the received power for the signal at the first wireless device (referred to here as UE A) is much greater than that at the other wireless devices in the test structure (step <NUM>). Here, the received power for the signal at the first wireless device is much greater than that at the other wireless devices if it is greater than the received power at the other wireless devices by a predetermined amount. This predetermined amount may be determined based on reference measurements for the received power of the signal at the same wireless devices. If so, the massive MIMO radio validator <NUM> determines that the massive MIMO transceiver <NUM> is healthy (step <NUM>). Otherwise, the massive MIMO radio validator <NUM> determines that the massive MIMO transceiver <NUM> is non-healthy (step <NUM>).

<FIG> illustrates an example of network-assisted over-the-air supervision. In this example, the radio system <NUM> is implemented in a radio unit (RU_1) of a radio access node. Network-assisted over-the-air supervision may be performed as follows. RU_1 is in testing mode (quiet time), and RU_2, which is a radio unit of a neighboring radio access node, is also in testing mode. RU_1 is configured to tilt its digital downlink beams directly towards RU_2, in contrast to tilting down to avoid interference to each other. The receive beams of RU_2 are titled to receive test signals transmitted by RU_1 with its Uplink Spectrum Analyzer (ULSA) turned on. At the radio access node in which RU_2 is implemented, the received signals are used to detect whether there are any obstacles that impair the downlink beam shape of RU_1 or whether there is any problem with the RU_1 antenna branches that results in distortion the beam from RU_1. For example, a massive MIMO radio validator <NUM> associated with RU_2 compares a measurement(s) on the received test signal(s) from RU_1 against a corresponding reference value(s). If the measurement(s) differ from the reference value(s) by more than a predefined threshold amount, then an error is detected. RU_2 sends an indication of whether an error is detected to RU_1, where the indication is processed by the massive MIMO radio validator <NUM> associated with the RU_1. Alternatively, RU_2 may send the measurement value(s) back to RU_1 or the massive MIMO radio validator <NUM> associated with RU_1, e.g., via an interface between the two radio access nodes. The massive MIMO radio validator <NUM> associated with RU_1 then determines whether there is an error with the massive MIMO transceiver <NUM> of RU_1 by, e.g., comparing the measurement value(s) with corresponding reference value(s). In either case, if an error is detected, in an example, RU_1 performs the same procedure with RU_3, which is the radio unit of another neighboring radio access node. If the error persists, the massive MIMO radio validator <NUM> of RU_1 takes one or more actions in an attempt to correct the error, as discussed above.

Further improvement can be performed on the base algorithm. If both AASs are in line-of-sight of each other without adjusting the antenna tilt, the calibration beam can be created to point to each other while the radio access nodes continue to provide service. This validation while in service gives an instantaneous confirmation that the network is operating as planned. This can be accomplished in several ways. As one example, a beam is formed on a dedicated radio resource block. This is the same as forming a beam to a wireless device. In this case, both the scheduler and digital beam forming are involved. This approach also impacts the capacity of the existing cell. As another example, a dedicated narrow band cell which shares the antenna element can be used. With the introduction of NB-IoT, a cell can be formed in the guardband of the carrier. Doing so does not impact existing cell configuration and resources.

<FIG> is a flow chart that illustrates the operation of the massive MIMO radio validator <NUM> to perform network-assisted over-the-air supervision in accordance with an embodiment of the present disclosure. This process illustrates steps 604B and <NUM> of <FIG> in more detail in accordance with an embodiment. As illustrated, the massive MIMO radio validator <NUM> transmits a test signal via the massive MIMO transceiver <NUM> to a neighboring radio access node using a transmit beam(s) in a direction of the neighboring radio access node (step <NUM>). The massive MIMO radio validator <NUM> receives, from the neighboring radio access node, an indication of whether the neighboring radio access node detected an impairment to the transmit beam(s) (step <NUM>). Upon determining that there is an impairment, the massive MIMO radio validator <NUM> transmits a test signal(s) to an additional neighboring radio access node(s) using a transmit beam(s) in a direction of the additional neighboring radio access node(s) (step <NUM>). The massive MIMO radio validator <NUM> receives, from the additional neighboring radio access node(s), an indication(s) of whether the additional neighboring radio access node(s) detected an impairment (step <NUM>). Then, based on the information collected in steps <NUM> through <NUM>, the massive MIMO radio validator <NUM> determines the status, or health, of the massive MIMO transceiver <NUM> (step <NUM>).

<FIG> illustrates one example of a cloud infrastructure that can be used to implement aspects of the present disclosure in accordance with an example. The cloud infrastructure enables a radio access node in which the radio system <NUM> is implemented to avoid isolation and to work cooperatively with other radio access nodes. Some example features that may be provided by the cloud infrastructure include:.

With a UE-like external device for measurement, there are several ways of utilizing baseband signals and protocols to assist the supervision by measurement and monitoring. Some examples are:.

One common aspect of these examples is that the baseband Digital Unit (DU) of the radio access node creates a special scheduling scheme to treat the UE-like measurement device as one of the UEs, but in a way such that the measurement and monitoring goal can be achieved. For example, the baseband unit can generate a sweeping signal along its horizontal plane and vertical plane to detect if there is any obstacle appeared in the last detection period. As one of the options, the transmitted signals and scheduling scheme are pre-designed and known at both the radio access node and UE-like measurement device such that the UE-like measurement device knows what kind of signal it is expected to receive. As another of option, the transmitted signals and scheduling scheme are dynamically generated and signaled to the UE-like measurement device such that the radio access node could adjust the supervision state based on the changing situation and diagnose unusual behavior of the AAS under supervision. As yet another option, the radio access node and UE-like measurement device could exchange information using the established communication link and the content of the information could be used to facilitate functional operation of AAS supervision.

In an example, an uplink channel(s) from the UE-like measurement device can be used for feedback of the results and observations such that the massive MIMO radio validator <NUM> can adjust the supervision strategy dynamically. It could be a scan through predefined test cases repeatedly or trigger special measurement event in case un-normal behavior is observed.

Other than using a UE-like measurement device which is dedicated for AAS supervision purpose, the radio access node can also schedule regular wireless devices (e.g., regular UEs) in the coverage area to assist with AAS supervision. One such option could be regular wireless devices in the coverage area configured with special reference signals (e.g., Channel State Information Reference Signal (CSI-RS)) and feedback channel state information(CSI), including receive power measurement, which could assist AAS supervision instead of for data transmission to the wireless devices. The aforementioned cell edge detection can use a regular subscriber UE or a specialized UE.

As discussed above, legacy (passive) antenna systems are manufactured and packaged with one or a few connectors which are accessible for connecting with a radio transceiver and for testing. In <NUM>, massive MIMO AAS substantially increases the number of physical antenna ports for digital beamforming as required by the mobile system specification. Beamforming verification requires measuring from these antenna ports collectively, in contrast to independent measurement as before.

Thus, massive MIMO is a new challenge and requires evolution of existing solutions. An embodiment of the present disclosure relates to enhancements of conventional component based validation and additionally provides over-the-air validation. An embodiment of the present disclosure addresses scalability and densification challenges. In particular, the digital baseband unit of a radio access node includes a new function (i.e., the massive MIMO radio validator <NUM>) that performs periodic validation of the massive MIMO transceiver <NUM>. In an example, the massive MIMO radio validator <NUM> injects a test vector into the massive MIMO transceiver <NUM> in conjunction with component based validation. Measurements from the internal observation points are collected and analyzed by the massive MIMO radio validator <NUM> for functional integrity testing. An embodiments of the present disclosure also addresses the need for continuous supervision. In an example, the internal component based supervision is performed periodically such that, e.g., any software or hardware component degradation trend can be detected early. Further, in an example, external over-the-air supervision is performed to discover environmental degradation such as an obstruction due to, e.g., a new building or fallen trees. The over-the-air supervision uses a mobile wireless device(s), a fixed mounted wireless device(s), or another radio access node(s) to generate or detect a test signal (e.g., a reference signal) so that any sudden radio frequency path degradation can be detected early.

<FIG> is a schematic block diagram of a wireless device <NUM> (e.g., a UE) according to an unclaimed example. As illustrated, the wireless device <NUM> includes circuitry <NUM> comprising one or more processors <NUM> (e.g., Central Processing Units (CPUs), ASICs, FPGAs, DSPs, and/or the like) and memory <NUM>. The wireless device <NUM> also includes one or more transceivers <NUM> each including one or more transmitters <NUM> and one or more receivers <NUM> coupled to one or more antennas <NUM>. In an unclaimed example, the functionality of the wireless device <NUM> described herein may be implemented in hardware (e.g., via hardware within the circuitry <NUM> and/or within the processor(s) <NUM>) or be implemented in a combination of hardware and software (e.g., fully or partially implemented in software that is, e.g., stored in the memory <NUM> and executed by the processor(s) <NUM>).

In an unclaimed example, a computer program including instructions which, when executed by the at least one processor <NUM>, causes the at least one processor <NUM> to carry out at least some of the functionality of the wireless device <NUM> according to any of the embodiments described herein is provided. In an unclaimed example, a carrier containing the aforementioned computer program product is provided.

<FIG> is a schematic block diagram of a wireless device <NUM> (e.g., a UE) according to an unclaimed example. The wireless device <NUM> includes one or more modules <NUM>, each of which is implemented in software. The module(s) <NUM> provide the functionality of the wireless device <NUM> described herein.

<FIG> is a schematic block diagram of a radio access node <NUM> (e.g., an eNB or gNB) according to an embodiment of the present disclosure. As illustrated, the radio access node <NUM> includes a digital baseband unit <NUM> that includes circuitry comprising one or more processors <NUM> (e.g., CPUs, ASICs, DSPs, FPGAs, and/or the like) and memory <NUM>. The digital baseband unit <NUM> also includes a network interface <NUM>. The radio access node <NUM> also includes one or more radio units <NUM> that each include one or more transmitters <NUM> and one or more receivers <NUM> coupled to one or more antennas <NUM>. In an example, the massive MIMO radio validator <NUM> is implemented in the digital baseband unit <NUM>, and the massive MIMO transceiver <NUM> is implemented in the radio unit(s) <NUM>. The functionality of the massive MIMO radio validator <NUM> may be implemented as hardware or a combination of hardware and software in the digital baseband unit <NUM>. Some or all of the functionality of the massive MIMO radio validator <NUM> may be implemented in software that is, e.g., stored in the memory <NUM> and executed by the processor(s) <NUM>.

<FIG> is a schematic block diagram that illustrates a virtualized embodiment of a radio access node <NUM> according to an example. As used herein, a "virtualized" radio access node <NUM> is a radio access node <NUM> in which at least a portion of the functionality of the radio access node <NUM> is implemented as a virtual component (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, the radio access node <NUM> optionally includes the digital baseband unit <NUM>, as described with respect to <FIG>. In addition, the radio access node <NUM> also includes the one or more radio units <NUM>, as described with respect to <FIG>. The digital baseband unit <NUM> (if present) is connected to one or more processing nodes <NUM> coupled to or included as part of a network(s) <NUM> via the network interface <NUM>. Alternatively, if the digital baseband unit <NUM> is not present, the one or more radio units <NUM> are connected to the one or more processing nodes <NUM> via a network interface(s). In an example, the functionality of the massive MIMO radio validator <NUM> is implemented at one or more of the processing nodes <NUM> or distributed across one or more of the processing node <NUM> and the digital baseband unit <NUM>. Each processing node <NUM> includes one or more processors <NUM> (e.g., CPUs, ASICs, DSPs, FPGAs, and/or the like), memory <NUM>, and a network interface <NUM>.

In this example, functions <NUM> of the radio access node <NUM> (e.g., the functions of the massive MIMO radio validator <NUM>) described herein are implemented at the one or more processing nodes <NUM> or distributed across the digital baseband unit <NUM> and the one or more processing nodes <NUM> in any desired manner. In an example, some or all of the functions <NUM> of the radio access node <NUM> described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) <NUM>. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) <NUM> and the digital baseband unit <NUM> (if present) or alternatively the radio unit(s) <NUM> is used in order to carry out at least some of the desired functions. Notably, in an example, the digital baseband unit <NUM> may not be included, in which case the radio unit(s) <NUM> communicates directly with the processing node(s) <NUM> via an appropriate network interface(s).

In an example, higher layer functionality (e.g., layer <NUM> and up and possibly some of layer <NUM> of the protocol stack) of the radio access node <NUM> may be implemented at the processing node(s) <NUM> as virtual components (i.e., implemented "in the cloud") whereas lower layer functionality (e.g., layer <NUM> and possibly some of layer <NUM> of the protocol stack) may be implemented in the radio unit(s) <NUM> and possibly the digital baseband unit <NUM>.

In an example, a computer program including instructions which, when executed by the at least one processor <NUM> and/or <NUM>, causes the at least one processor <NUM> and/or <NUM> to carry out the functionality of the radio access node <NUM>, <NUM> or a processing node <NUM> according to any of the (unclaimed) examples and embodiments described herein is provided. In an example, a carrier containing the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as the memory).

<FIG> is a schematic block diagram of a radio access node <NUM> according to an unclaimed example. For instance, the modules <NUM> may include a calibrating module operable to perform the function of step <NUM> of <FIG>, an obtaining module operable to perform the function of step <NUM> of <FIG>, a monitoring module operable to perform the function of step <NUM> of <FIG>, a determining module operable to perform the function of step <NUM> of <FIG>, and an acting module operable to perform the functions of steps <NUM> through <NUM> of <FIG>.

Claim 1:
A method performed by a radio system (<NUM>) implemented in a radio access node (<NUM>) comprising a Multiple Input Multiple Output, MIMO, transceiver (<NUM>) and processing circuitry, to perform supervision of the MIMO transceiver (<NUM>), comprising the following steps performed by the processing circuitry:
performing (604B) continuous network-assisted over-the-air based supervision of beam directivity and/or beam shape of the MIMO transceiver of the radio system (<NUM>) while the radio access node is in service, comprising:
- transmitting (<NUM>) a test signal to a neighboring radio access node using one or more transmit beams in a direction of the neighboring radio access node;
- receiving (<NUM>), from the neighboring radio access node, an indication of whether the neighboring radio access node detected an impairment to the one or more transmit beams in the direction of the neighboring radio access node; and
- upon determining that there is an impairment to the one or more transmit beams based on the indication received from the neighboring radio access node, for each additional neighboring radio access node of at least one additional neighboring radio access node:
-- transmitting (<NUM>) a second test signal to the additional neighboring radio access node using one or more transmit beams in a direction of the additional neighboring radio access node; and
-- receiving (<NUM>), from the additional neighboring radio access node, an indication of whether the additional neighboring radio access node detected an impairment to the one or more transmit beams in the direction of the additional neighboring radio access node;
determining (<NUM>) a status of the MIMO transceiver based on results of performing (604B) continuous network-assisted over-the-air based supervision of beam directivity and/or beam shape of the MIMO transceiver of the radio system (<NUM>), comprising:
- determining (<NUM>) that there is an error in the MIMO transceiver based on the indications received from the neighboring radio access node and the at least one additional neighboring radio access node; and
taking (<NUM>, <NUM>) an action based on the status of the MIMO transceiver, comprising:
- initiating (<NUM>) one or more actions to address the error.