User equipment beam mapping

Abstract

A method, comprising: determining, at a user device, a current operating condition of a user device; identifying whether an antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user device is stored by the user device for the current operating condition of the user device; and applying, when the antenna configuration is identified, the antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user device.

Description

Technical Field

[0001] Various example embodiments are directed to methods, computer programs and apparatus for maintaining user equipment (UE) beam correspondence. Background Art

[0002] In wireless telecommunications networks such as 5G networks, uplink and downlink beams are formed between user equipment and network nodes to support communication between the user equipment and the network nodes. Although techniques exist for configuring those uplink and downlink beams, poor performance of communication between the user equipment and the network nodes may occur. Therefore, it is desirable to provide improved techniques for supporting communication between user equipment and network nodes. Summary of the invention

[0003] The scope of protection sought by various embodiments of the present invention is set out in the independent claims. Embodiments and features described in this specification that do not fall within the scope of the independent claims, if any, should be interpreted as examples that help understand the various embodiments of the present invention.

[0004] According to various but not necessarily all embodiments of the present invention, a method is provided, comprising: determining, at a user device, a current operating condition of a user device; identifying whether an antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user device is stored by the user device for the current operating condition of the user device; and when the antenna configuration is identified, applying the antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user device.

[0005] The method may include, when no antenna configuration is identified, signaling that for a current operating condition of the user equipment, a reference signal scanning process is required to identify an antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user equipment.

[0006] The method may include, when no antenna configuration is identified, performing a reference signal scanning process for a current operating condition of the user equipment to identify an antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user equipment.

[0007] The method may include performing a reference signal scanning procedure regardless of whether the antenna configuration has been identified in response to scheduling by the network node.

[0008] The method may include storing an antenna configuration identified by a reference signal scanning process for a current operating condition of the user equipment.

[0009] The method may include preventing storage of an antenna configuration identified by a reference signal scanning process for a current operating condition of the user equipment when a predetermined condition occurs.

[0010] The predetermined condition may instruct the user equipment to operate in a non-repeatable manner.

[0011] The method may include storing the antenna configuration with the additional operating condition when an at least partially repeatable change in a condition of the user equipment is detected.

[0012] The method may include using the antenna configuration for the current operating condition of the user equipment and at least one other stored antenna configuration to interpolate at least one antenna configuration for maintaining correspondence between user equipment transmit beams and receive beams for other user equipment operating conditions.

[0013] The method may include storing the interpolated antenna configurations for other user equipment operating conditions.

[0014] The method may include using the antenna configuration for the current operating condition of the user equipment and at least one other stored antenna configuration to extrapolate at least one antenna configuration for maintaining correspondence between user equipment transmit beams and receive beams for other user equipment operating conditions.

[0015] The method may include storing the extrapolated antenna configurations for other user equipment operating conditions.

[0016] The at least one stored antenna configuration may include an antenna configuration identified by a reference signal scanning process.

[0017] The method may include using at least one of the interpolated antenna configuration and the extrapolated antenna configuration to recursively recalculate an antenna configuration for maintaining a correspondence between a user equipment transmit beam and a receive beam for other user equipment operating conditions.

[0018] The method may include using the antenna configuration identified by the reference signal scanning process to recursively recalculate the antenna configuration for maintaining correspondence between the user equipment transmit beam and the receive beam for other user equipment operating conditions.

[0019] The method includes dynamically providing to a network node an indication of whether the user equipment is capable of maintaining a correspondence between a transmit beam and a receive beam of the user equipment for current operating conditions of the user equipment.

[0020] Dynamically providing may include providing a change in indication when the user device switches between an antenna configuration that is identified by the user device for maintaining correspondence between a transmit beam and a receive beam of the user device and an antenna configuration that is not identified by the user device for maintaining correspondence between a transmit beam and a receive beam of the user device and stored by the user device for maintaining correspondence between a transmit beam and a receive beam of the user device for the current operating conditions of the user device.

[0021] Dynamically providing may include providing the change in the indication while remaining in a radio resource control connected mode.

[0022] The indication may indicate that the user equipment is of a type that supports autonomous beam correspondence when the antenna configuration is identified for the current operating condition of the user equipment as being stored by the user equipment for maintaining correspondence between the transmit beam and the receive beam of the user equipment.

[0023] The indication may indicate that the user equipment is a TS 38.101-2 bit 1 user equipment.

[0024] The indication may indicate that the user equipment is of a type requiring network support for beam correspondence when the antenna configuration is not identified for current operating conditions of the user equipment as stored by the user equipment for maintaining correspondence between transmit beams and receive beams of the user equipment.

[0025] The indication may indicate that the user equipment is TS 38.101-2 bit 0 user equipment.

[0026] The operating conditions may include at least one of: operating temperature, operating frequency, operating bandwidth, operating power, modulation scheme, proximity mismatch, and operating voltage of the user equipment.

[0027] Antenna configuration may include antenna weight settings.

[0028] The reference signal may include a sounding reference signal.

[0029] The method may be a user equipment method and / or performed at a user equipment.

[0030] According to various but not necessarily all embodiments of the present invention, a computer program is provided, comprising instructions for causing an apparatus to perform at least the following operations: determining, at the user equipment, a current operating condition of a user equipment; identifying whether an antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user equipment is stored by the user equipment for the current operating condition of the user equipment; and when the antenna configuration is identified, applying the antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user equipment.

[0031] The computer program may include instructions for causing an apparatus to perform the method set forth above.

[0032] According to various but not necessarily all embodiments of the present invention, a device is provided, comprising: a component for determining a current operating condition of a user device at a device including the user device; a component for identifying whether an antenna configuration for maintaining a correspondence between a transmit beam and a receive beam of the user device is stored by the user device for the current operating condition of the user device; and a component for applying the antenna configuration for maintaining a correspondence between a transmit beam and a receive beam of the user device when the antenna configuration is identified.

[0033] The apparatus may include means for signaling, when no antenna configuration is identified, that for current operating conditions of the user equipment, a reference signal scanning process is required to identify an antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user equipment.

[0034] The apparatus may include means for performing a reference signal scanning process for a current operating condition of the user equipment to identify an antenna configuration for maintaining correspondence between a transmit beam and a receive beam of the user equipment when no antenna configuration is identified.

[0035] The apparatus may include means for performing a reference signal scanning procedure regardless of whether the antenna configuration has been identified in response to scheduling by the network node.

[0036] The apparatus may include means for storing an antenna configuration for a current operating condition of the user equipment identified by a reference signal scanning procedure.

[0037] The apparatus may include means for preventing storage of an antenna configuration for a current operating condition of the user equipment identified by the reference signal scanning process when a predetermined condition occurs.

[0038] The predetermined condition may instruct the user equipment to operate in a non-repeatable manner.

[0039] The apparatus may include means for storing the antenna configuration with the additional operating condition when an at least partially repeatable change in a condition of the user equipment is detected.

[0040] The apparatus may include means for using the antenna configuration for the current operating condition of the user equipment and at least one other stored antenna configuration to interpolate antenna configurations for maintaining correspondence between user equipment transmit beams and receive beams for other user equipment operating conditions.

[0041] The apparatus may include means for storing the interpolated antenna configurations for other user equipment operating conditions.

[0042] The apparatus may include means for using the antenna configuration for the current operating condition of the user equipment and at least one other stored antenna configuration to extrapolate an antenna configuration for maintaining correspondence between user equipment transmit beams and receive beams for other user equipment operating conditions.

[0043] The apparatus may include means for storing the extrapolated antenna configuration for other user equipment operating conditions.

[0044] The at least one stored antenna configuration may include an antenna configuration identified by a reference signal scanning process.

[0045] The apparatus may include means for recursively recalculating antenna configurations for maintaining correspondence between user equipment transmit beams and receive beams for other user equipment operating conditions using at least one of the interpolated antenna configuration and the extrapolated antenna configuration.

[0046] The apparatus may include means for recursively recalculating antenna configurations for maintaining correspondence between user equipment transmit beams and receive beams for other user equipment operating conditions using the antenna configurations identified by the reference signal scanning process.

[0047] The apparatus may include means for dynamically providing to a network node an indication of whether a user equipment is capable of maintaining a correspondence between a user equipment transmit beam and a receive beam for a current operating condition of the user equipment.

[0048] A component for dynamically providing may include a component for providing a change in indication when a user device switches between an antenna configuration that is identified and stored by the user device for maintaining correspondence between a transmit beam and a receive beam of the user device for a current operating condition of the user device and an antenna configuration that is not identified and stored by the user device for maintaining correspondence between a transmit beam and a receive beam of the user device for a current operating condition of the user device.

[0049] The means for dynamically providing may include means for providing the change in indication while remaining in a radio resource control connected mode.

[0050] The indication may indicate that the user equipment is of a type that supports autonomous beam correspondence when the antenna configuration is identified for the current operating condition of the user equipment as being stored by the user equipment for maintaining correspondence between the transmit beam and the receive beam of the user equipment.

[0051] The indication may indicate that the user equipment is a TS 38.101-2 bit 1 user equipment.

[0052] The indication may indicate that the user equipment is of a type requiring network support for beam correspondence when the antenna configuration is not identified for current operating conditions of the user equipment as stored by the user equipment for maintaining correspondence between transmit beams and receive beams of the user equipment.

[0053] The indication may indicate that the user equipment is TS 38.101-2 bit 0 user equipment.

[0054] The operating conditions may include at least one of: operating temperature, operating frequency, operating bandwidth, operating power, modulation scheme, proximity mismatch, and operating voltage of the user equipment.

[0055] Antenna configuration may include antenna weight settings.

[0056] The reference signal may include a sounding reference signal.

[0057] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. The dependent claims may be combined with features of the independent claims as appropriate, and with combinations other than those explicitly set out in the claims.

[0058] Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature providing that function or an apparatus feature being adapted or configured to provide that function. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0060] Figure 1 A. Figure 1 B and Figure 1 C shows uplink / downlink beam alignment and misalignment;

[0061] Figure 2 is a block diagram of a simplified user equipment for transmitting and receiving;

[0062] Figure 3 The beam alignment process is shown;

[0063] Figure 4 Example parameters affecting beam correspondence are listed and a subset of an example table related to antenna configuration parameters is schematically shown;

[0064] Figure 5 and Figure 6 schematically illustrates the storage of antenna configuration information under different operating conditions;

[0065] Figure 7 A machine learning model is shown;

[0066] Figure 8An example of a method performed by a user equipment is schematically shown; and

[0067] Fig. 9 Some components of user equipment 20 are shown in detail. DETAILED DESCRIPTION

[0068] Before discussing the example embodiments in any more detail, an overview will first be provided. Some embodiments provide an arrangement in which a user device identifies and stores antenna configurations that provide uplink / downlink (transmit / receive) beam correspondence under different operating conditions. This enables the user device to select and apply those antenna configurations when operating under those operating conditions. When an operating condition is encountered for which no antenna configuration is stored, the user device can trigger support from the network to feedback which antenna configuration provides sufficient uplink / downlink (transmit / receive) beam correspondence under the operating condition. Storing antenna configurations avoids the need for a support process that may otherwise occur to ensure uplink / downlink beam correspondence under those operating conditions. In addition, the user device can estimate (by interpolation and / or extrapolation) antenna configurations for other operating conditions that have not yet been encountered. As the number of antenna configurations stored (and interpolated and / or extrapolated) for different operating conditions increases, the network resources required to determine the antenna configurations for different operating conditions are reduced. In addition, when the network detects that a mismatch is occurring, the network can still instruct the user equipment to implement a process to ensure that the uplink / downlink (transmit / receive) beam corresponds under its current operating conditions and overwrite any stored antenna configurations. In addition, the user equipment should infer that there are other operating conditions that affect the uplink / downlink (transmit / receive) beam correspondence that are not currently associated with any stored antenna configurations, and the antenna configuration associated with the other operating conditions can also be stored. The user equipment is therefore able to dynamically signal the network when it needs it and does not require network resources to maintain uplink / downlink (transmit / receive) beam correspondence. This provides a self-learning user equipment that can be deployed in practice and learn the appropriate antenna configuration without having to be pre-configured with an antenna configuration for the expected operating conditions, while avoiding unnecessary resource consumption on the network.

[0069] Uplink beam misalignment

[0070] Figure 1 A. Figure 1 B and Figure 1C shows uplink / downlink beam correspondence and misalignment. gNB 10 has uplink beam 15 (through which transmissions from user equipment 10 are received) and downlink beam 17 (through which transmissions to user equipment 10 are sent). User equipment 20 has uplink beam 25 (through which transmissions from user equipment 10 are sent) and downlink beam 27 (through which transmissions to user equipment 10 are received).

[0071] like Figure 1 As can be seen in A, uplink beam 25 and downlink beam 27 are corresponding (meaning they are aligned and parallel) and they point to the corresponding uplink beam 15 and downlink beam 17.

[0072] like Figure 1 As can be seen in B, the beam correspondence of the user equipment is preserved as uplink beam 25 and downlink beam 27 are still aligned and parallel, but now they are not pointing to the corresponding uplink beam 15 and downlink beam 17, which results in a suboptimal downlink and uplink with similar reduced gain on both the uplink and downlink.

[0073] Figure 1C shows a misalignment between uplink beam 25 and downlink beam 27, as uplink beam 25 and downlink beam 27 are no longer aligned and parallel, but are now offset by angle A. This misalignment can occur for a variety of reasons and can occur dynamically in the field due to, for example, impedance changes of power amplifiers, low noise amplifiers and / or switches affected by temperature, design tolerances, operating power levels (which can cause small offsets), and power imbalances. In particular, mismatches towards the antennas and / or towards one or more amplifiers can affect the uplink and downlink directivities, whereby the beams will exhibit different directivities towards the gNB 10. It will be appreciated that this is not limited to such events, and can include any type of undesirable change in the radio frequency (RF) performance of any component(s) associated with the antenna control circuitry, receiver chain(s), and transmitter chain(s). Furthermore, if the direction of uplink beam 25 does not correspond to downlink beam 27, power is ultimately not received at the gNB 10. The problem of beam misalignment is not as severe for the gNB 10 as for the user equipment 20. This is because the degrees of freedom allocated for antenna design on the gNB 10 are significantly higher than on the user equipment 20, where the mmWave antenna array will have to share volume with other electronic components and (multiple) antennas for communications below 6 GHz. In addition, the user equipment 20 has a large number of constraints, such as, for example, supporting very large bandwidths for global coverage, and they are typically implemented using more cost-effective embedded components, which cannot achieve tolerance levels and lead to impedance variations across different operating settings. Therefore, the impedance (input and / or output impedance) of one or more electronic components or modules within the receive chain and the transmit chain may change and change with different power and gain settings, which means that even balancing the effects of any impedance mismatch will help little because the user equipment 20 adapts to the closed-loop power regulation of the gNB 10.

[0074] Thus, the uplink / downlink beam correspondence is preserved if the following conditions are met: the same antenna element weights used for uplink and downlink result in the same beam gain and direction for uplink and downlink; the antenna element weights can be offset by pre-characterized values ​​to obtain the same beam gain and direction for uplink and downlink; two "codebooks" of beam weight vectors have been established, one for the uplink and the second for the downlink. Each beam weight vector in the uplink codebook is paired one-to-one with a beam weight vector in the downlink codebook, so that paired uplink beam weight vectors and downlink beam weight vectors have the same beam and gain direction. If these are not met, the beam correspondence is broken and the uplink will be as Figure 1 Shown in C is misalignment.

[0075] exist Figure 2 The impedance mismatch within the user equipment 20 can be seen in more detail in FIG. Figure 2 is a simplified block diagram of the transmission and reception of the user equipment 20, which shows different impedances towards the low noise amplifier and the power amplifier. It will be appreciated that in addition to the input impedance mismatch, there may also be an output impedance mismatch between components or modules, and this difference between the output impedance and the input impedance may affect the power transfer between these components or modules at the frequency(s) of interest. The impedance of the individual antenna elements in the antenna array Zant will change as a function of the desired frequency and the angular direction of the configured main beam. In this way, each antenna element will present a different impedance at any given time, which will affect the performance of the (multiple) independent power amplifiers PA and (multiple) low noise amplifiers (LNA) connected to that particular antenna element. The power amplifier is typically much more sensitive to changes in load impedance than the low noise amplifier, so the effects of changes in the power amplifier load impedance are not captured during the beam alignment process, as they only rely on the downlink. The effects of changes in the power amplifier load impedance will need to be part of the calibration or configuration of the transmit beam control and configuration, ensuring that the receive beam direction and the transmit beam direction are aligned during calibration / configuration. Furthermore, the power amplifier misbehavior is not only caused by changes in the load impedance, but also by factors related to the power amplifier, such as output power level, ambient temperature, and potential gain mode. Therefore, the actual radiation pattern formed by the antenna array will be affected by these different power amplifier and low noise amplifier misbehaviors and result in different radiation patterns for the downlink and uplink, even with the same array configuration (weights). These differences in radiation patterns may be negligible for some array / RF front-end configurations (line of sight at low power), but may be severe for other configurations (angle steering directions at high power) and result in beam misalignment when the configuration or calibration is not adequate for the circuit state.

[0076] Beam Alignment

[0077] For 5G New Radio (NR) Release 15, the beam alignment procedure between the user equipment 20 and the gNB 10 is described in 3GPP TR 38.802 Section 6.1.6 and TS 38.214 Section 5.2. The beam alignment procedure includes the following reference Figure 3 The 3 main stages described.

[0078] Phase #1: The UE 20 is configured for wide beam reception while the gNB 10 is performing downlink synchronization signal block (SSB) beam scanning. The UE 20 measures the reference signal received power (RSRP) for all SSB beams received and reports back to the gNB 10 by sending a suitable known signal called a preamble at a given time instance (Random Access Channel (RACH) opportunity) using the same beam configuration as when receiving, according to the configuration provided by the gNB 10 via the System Information Block 1 (SIB1) and decoded by the UE 20 upon reception of the best SSB beam (which includes the Master Information Block (MIB), which in turn includes an indication of the resources used to receive SIB1). In connected mode, the UE 20 may be configured to measure a set of SSBs, where the reporting is based on Level 1 (L1)-RSRP.

[0079] Phase #2: UE 20 is configured for wide beam reception while gNB 10 is performing refined downlink channel state information reference signal (DL CSI-RS) beam scanning. UE 20 uses the same beam configuration as on reception to select the best beam identification (ID) and reports it back to gNB 10. The selection is a function of one or more metrics measured by the UE, such as RSRP, Channel Quality Indicator (CQI), Rank Indication (RI), to name a few.

[0080] Phase #3: The gNB 10 transmits with the best beam obtained in phase #2. In this phase, and subject to the specific CSI-RS resources and CSI-reporting configuration, the UE 20 may scan the refined receive beam settings for identifying the best narrow receive beam. This selection does not need to be reported to the gNB 10, i.e., in this case the "Reporting Amount" field in the IE CSI-ReportConfig is set to "None". At the end of phase #3, the alignment between the gNB 10 transmit beam and the UE 20 receive beam is obtained for maximizing directional gain and minimal interference to other users in the serving and neighboring cells. Note that the beam alignment process is based on downlink measurements only, so it is assumed that the transmit / receive beam correspondence is preserved at all times. Thus, uplink / downlink beam correspondence is preserved if the following conditions are met: the same antenna element weights for uplink and downlink result in the same beam gain and direction for uplink and downlink; the antenna element weights can be offset by pre-characterized values ​​to obtain the same beam gain and direction for uplink and downlink; two "codebooks" of beam weight vectors have been established, one for the uplink and a second for the downlink. Each beam weight vector in the uplink codebook is paired one-to-one with a beam weight vector in the downlink codebook, so that a paired uplink beam weight vector and downlink beam weight vector have the same beam and gain direction. If these are not met, the beam correspondence is broken and the uplink will behave as Figure 1 Shown in C is misalignment.

[0081] According to TS 38.101-2, and in particular 3GPP TSG RAN WG1 meeting #100-e R1 20000926, all user equipment 20 must support beam correspondence for frequency range 2 (FR2). Nevertheless, user equipment 20 can be classified into [bit-1] user equipment 20 and [bit-0] user equipment 20, where:

[0082] [Bit-1] The user equipment 20 autonomously supports the beam correspondence requirement, and

[0083] [Bit-0] The user equipment 20 needs additional sounding reference signal (SRS) scanning and

[0084] The network receives feedback to best aim the transmit beam at the user equipment 20.

[0085] However, the beam correspondence capability specification in Rel-15 / 16 does not take into account the dynamically changing nature of the beam correspondence state, but implicitly relies on the static implementation of the beam correspondence itself (when supported). However, the beam correspondence state depends on the operating conditions at the user equipment 20, so it does not have a static nature in actual deployment.

[0086] In practice, maintaining a "static" beam correspondence may result in scheduling of SRS scans that are not actually needed, thereby adding unnecessary overhead and interference and reducing throughput. Similarly, beam mismatch is more likely to occur when the user equipment 20 operates under non-ideal conditions. In this case, if the SRS scans are not scheduled frequently enough, then Figure 1 The misalignment shown in C can result in severe uplink loss.

[0087] [Bit-0] User equipment 20 requires SRS scanning to align their uplink beams, however SRS scanning consumes resources and time and causes throughput degradation. Furthermore, they must be scheduled appropriately for each user equipment 20 and misalignment falling into the null value can cause up to 30dB link loss and thus possible RLF (Radio Link Failure). The severity of the problem increases as the beams become narrower (or, alternatively, with the associated increased demand for high beam direction accuracy).

[0088] Parameters (operating conditions) that affect beam correspondence may be temperature, operating frequency, required antenna impedance bandwidth, power level, modulation, supply voltage and proximity mismatch, as well as some parameters specific to mmW operation such as antenna array steering angle, etc. In addition, user-influenced parameters may affect beam correspondence, such as changes caused by a case placed on the user device 20 by the user, how the user device 20 is held (the user's fingers / hands / head / other body part on or near the antenna(s) of the user device 20), whether the user device 20 is used adjacent to or in contact with metal objects outside the user device 20 and / or non-metallic objects outside the user device 20 (which are lossy at RF), and in what way the user device 20 is oriented during use, etc. In order to produce a [Bit-1] UE, characterization / calibration will have to be performed for each permutation of the above parameters. The number of such tests will be in the order of millions (see Figure 4 ), and each single user equipment 20 will need it. Therefore, characterizing / calibrating each single user equipment 20 at production time to ensure beam correspondence (i.e., as a [bit-1] UE) will require a long testing time and is therefore very expensive.

[0089] exist Figure 4 The size of the problem is illustrated in . If all permutations are included, the number of over-the-air tests required to ensure beam correspondence for a single user device 20 in a controlled environment can easily be in the order of millions. Figure 4The 1.6 million permutations shown in are for only one angular beam setting, so this number must be multiplied by the number of steering angles for any mmWave user device 20. Taking a user device 20 with a single array of 1x4 elements for 2 polarizations as an example (i.e., 7x2=14 beams), 22 million tests are required on a single user device 20 to ensure beam correspondence. The number of permutations increases with the array size and the number of antenna panels on the user device 20. Considering a user device 20 with 4 panels of 1x8 dual-polarization elements (i.e., 15x2x4=120 beams), the number of conditions to be tested for each user device 20 increases to 192 million. Although these numbers may be high worst-case scenarios, even reducing the number of tests by characterizing only the most critical factors will still result in an impractically large number of over-the-air tests.

[0090] Figure 4 A proximity mismatch entry in the table refers to the user device 20 detecting a fixed load, such as a housing placed on the user device by the user (which is an example of a semi-permanent change in the array impedance) and taking it into account in the transmit beam correction; or detecting a user close to the active antenna panel and shutting down learning because it is impossible to predict how the user will affect the antenna array characteristics.

[0091] Obviously, [bit-1] user equipment 20 is preferred for the network because they do not need resources allocated to SRS scanning. Nevertheless, it is extremely expensive to produce [bit-1] user equipment 20. Thus, some embodiments address how [bit-0] user equipment 20 can be converted into [bit-1] user equipment 20 during actual use. In other words, how can a user equipment 20 that requires SRS scanning for its uplink beam alignment (i.e., [bit-0]) become a user equipment 20 that can autonomously align and track its UL beam (i.e., [bit-1]).

[0092] Antenna configuration learning for beam alignment

[0093] Some embodiments involve a [bit-0] user device 20 (which requires an SRS scan to align a transmit beam) and which has logic that learns in practice and over time how to autonomously realign its transmit beam, thereby becoming a [bit-1] user device 20. In this way, the user device 20 builds knowledge with each requested SRS scan and maps the realigned transmit beam to the currently used receive beam.

[0094] This is not trivial since there are several internal user equipment 20 parameters that can affect beam correspondence, these parameters can vary in unpredictable ways and the number of permutations to be tested per user equipment 20 can be very large, as described above.

[0095] Some embodiments store, associate, interpolate and build knowledge for the user equipment 20 to autonomously transition from a [bit-0] user equipment 20 (where UL SRS scanning is required to achieve beam correspondence) to a [bit-1] user equipment 20 (where it does not require the network to determine its best uplink beam). Some embodiments also return to [bit-0] in order to address new unexplored cases, such as new carrier aggregation combinations.

[0096] Furthermore, the user equipment 20 may identify parameter combinations for which it may appear as a [bit-1] user equipment 20 (e.g., in line of sight) and other parameter combinations for which it must first build knowledge in order to only appear as a [bit-0] user equipment 20. This may be viewed as a partial correspondence, and may vary depending on the current operating conditions of the user equipment 20. In this way, the user equipment 20 may be able to dynamically switch back and forth between [bit-0] and [bit-1] capabilities, and use appropriate signaling to request SRS scanning accordingly.

[0097] Thus, in general, the user device 20 can become a [bit-1] beam corresponding user device 20 by using instant stored knowledge through the requested SRS scan, i.e., storing updated antenna weight settings (codebook) for the reconfigured transmit beam and associated with the current receive beam configuration for each SRS scan for each event of beam mismatch that has occurred; the user device 20 can become a [bit-1] beam corresponding user device 20 by using instant constructed knowledge through the requested SRS scan, i.e., interpolating and extrapolating the updated transmit beam configuration across different parameters, even if such a particular beam mismatch event has not yet occurred; the user device 20 may include new parameters that affect the instant beam correspondence, such as specific fixed load mismatches (e.g., phone cases, new carrier aggregation / modulation and coding scheme (CA / MCS) cases downloaded over the air); in partial correspondence, the user device 20 can identify operating conditions that lead to updating [bit-0] / [bit-1] capabilities, requesting SRS scans, and calculating the number of SRS resources required during the scan.

[0098] Antenna configuration storage

[0099] Figure 5 The storage of antenna configuration information under different operating conditions is schematically shown (only a subset of the operating conditions are shown). In particular, Figure 5It is shown that for each SRS requested by the gNB 10, the user equipment 20 identifies and stores the corresponding transmit beam configuration 30 (i.e., phase shifter and / or power level values, etc.) for the realigned beams for those operating conditions. The user equipment 20 can then provide any interpolated transmit beam configuration 40 and / or extrapolated transmit beam configuration 50 for adjacent operating conditions without having to perform SRS scanning to establish those transmit beam configurations.

[0100] While some parameters that affect beam correspondence have been identified and can be repeated to build knowledge based on them, some other parameters lead to load mismatches and are very unpredictable. This is the case for a user touching the array, where each different grip will result in a different antenna loading. User presence may be detected by some user devices 20 having proximity sensors embedded on the array. Thus, due to the non-repeatability of antenna loading from user presence (and, for example, always requesting uplink SRS scanning), this antenna loading may be a parameter used to turn off beam correspondence learning. On the other hand, the antenna loading may be fixed in the case of, for example, changing the phone case. In this case, the beam correspondence learning may be dynamically updated to include this new parameter in the storage.

[0101] Bit-0 / bit-1 conversion

[0102] The user equipment 20 supports dynamic beam correspondence, which means that beam correspondence is guaranteed in some conditions, but not in other conditions. Two examples are given below to illustrate the dynamic correspondence attribute:

[0103] When UE 20 is operating in line of sight and ideal power and impedance conditions, beam correspondence can be guaranteed (UE 20 updates to [bit-1]); however, once UE 20 rotates and needs to serve the same gNB beam using a UE beam steered at the maximum angle, then UE 20 may not be able to guarantee beam correspondence and SRS scanning is required, UE 20 updates to [bit-0] to adjust its transmit beam)

[0104] When the user device 20 is operating in line of sight and under ideal power and impedance conditions, beam correspondence can be guaranteed (user device 20 updates to [bit-1]); however, once the user touches the user device 20, the user device 20 may not be able to guarantee beam correspondence and SRS scanning is required, (user device 20 updates to [bit-0])

[0105] Another example could be that the user equipment 20 exhibits correspondence in the average PA power setting (user equipment 20 updates to [bit-1]), although in cell edge or low signal-to-interference-plus-noise ratio (SINR) the user equipment 20 needs to increase its power amplifier power to the maximum and cannot maintain beam correspondence (user equipment 20 updates to [bit-0]).

[0106] The above three examples illustrate how relevant it is to dynamically update the beam correspondence capability of the user equipment 20. The dynamic beam correspondence user equipment 20 capability may be an event-triggered RRC signaling initiated by the user equipment 20 to update the current beam correspondence capability to the gNB 10.

[0107] After a certain number of SRS scanning events and averaging, the user equipment 20 can update the operating conditions that require SRS scanning in a timely manner. Finally, when the user equipment 20 has obtained SRS scanning coverage across the current operating space (across the defined parameter space), it can switch from [bit-0] to [bit-1] user equipment 20 and use appropriate signaling to indicate the current state or any transition to the network, which enables the network to reduce the resources allocated to support SRS scanning.

[0108] In addition, if Figure 6 As shown, the user device 20 can infer dynamic correspondence, which is also called partial correspondence. That is, although the user device 20 may know that it is not completely corresponding (i.e., it is not [bit-1] because the storage table is not full for all possible combinations), the user device 20 can also know that it is now operating within the parameters that lead to beam correspondence. The user device 20 can operate in a feature area 60, in which beam correspondence under some specific conditions can be guaranteed (for example, when the user device 20 operates under line of sight and ideal power and impedance conditions). In this case, the user device 20 may not request any SRS scans and update its capabilities to [bit-1]. In another case, the user device 20 can identify that it is operating in a non-feature area 70, in which SRS scanning is necessary to achieve beam correspondence. Therefore, the user device 20 can update its capabilities to [bit-0] and infer the number of SRS scans required to optimize resource allocation from the table.

[0109] Beam Correspondence Learning

[0110] like Figure 6As shown, some operating conditions have an updated user equipment 20 transmit beam configuration resulting from an SRS scan. For those operating conditions, this stores and associates knowledge from beam non-corresponding scenarios. Based on the updated entries after the SRS scan, the UE can interpolate and extrapolate neighboring conditions within a confidence interval. This is a build and learn towards becoming a [bit-1] user equipment 20.

[0111] Building beam correspondence knowledge requires storing the adjusted settings (i.e., phase shifter and / or power level values) after each successful SRS scan, as well as calculating the expected settings for neighboring conditions within a confidence threshold (interpolation, second-order interpolation, and extrapolation). Machine learning can be used to assist in this process, as will be explained in more detail below.

[0112] Depending on the current operating conditions, the completion status of the correspondence process and the confidence required to ensure the correspondence, the user device 20 supports switching back and forth between [bit-0] / [bit-1] whenever the user device 20 finds itself outside these boundaries and therefore needs to retrain.

[0113] It will be appreciated that beam correspondence learning may be performed by lookup tables and / or machine learning, depending on the complexity of the user device 20, the number of parameters it can sense and characterize, and the processing power of the user device 20.

[0114] As indicated above, some embodiments store information from the actual triggered SRS scans. If the number of parameters that affect beam correspondence in this particular user device 20 is limited, this can be achieved through a lookup table (LUT). Otherwise, if the number of parameters is very large and the user device 20 can benefit from a neural network approach to enhance the interpolation and extrapolation capabilities to quickly and more accurately fill the table, this can be achieved through machine learning (ML).

[0115] Lookup Table

[0116] If the UE beam correspondence parameters are limited to a relatively small number of the most critical parameters (e.g., power level, operating frequency, temperature), a dynamic LUT may be used to provide sensitivity across the critical factors. In the event of an SRS scan being requested to the gNB 10, the combination of critical beam correspondence parameters that resulted in the SRS scan request is stored in the LUT. In this way, the [bit-0] user equipment 20 can build and learn knowledge of some combinations of critical beam correspondence parameters to be used in future misalignment situations, as well as the adjusted parameters for updating the corresponding transmit beams. If no a priori knowledge exists for the current operating settings, a LUT parameter recalibration is performed and a [bit-1] to [bit-0] capability transmission is triggered.

[0117] Machine Learning

[0118] like Figure 7 As shown, in order to increase the robustness of the high-dimensional data set of beam corresponding parameters, a machine learning model such as, for example, a long short-term memory (LSTM) based model 110 can be adopted. LSTM 110 is a special type of recurrent neural network (RNN) that can remember information for a long time. Thus, in order to provide a longer period of learning neural network process, LSTM 110 can be applied.

[0119] When a large number of parameters and therefore a large number of possible combinations and permutations are considered, if the user equipment 20 beam corresponding parameters require non-critical parameters as well as critical parameters, an autonomous [bit-0] to [bit-1] method can alternatively be adopted to increase the UE knowledge of the necessity for the SRS scan request. In addition, a suitable interpolation method can be applied for every x parameter combinations to reduce the number of recalibrations and SRS events. The training accuracy can be improved by applying the LSTM-based model 110. The interpolated beam corresponding parameters and the non-interpolated beam corresponding parameters are passed through a conventional LSTM neural network. In this way, as the training phase is completed, the accuracy of the interpolated parameters increases.

[0120] LSTM 110 is a conventional LSTM neural network. The LSTM structure consists of a multi-dimensional input layer, which in this case is the beam correspondence parameter. The number of hidden layers representing the layers of the connected neural network depends on the predefined loss function or the expected prediction error.

[0121] At block 1 the current operating conditions are established and a determination is made as to whether an entry is already stored in the data set 100 that provides an antenna configuration that maintains beam alignment for those current operating conditions.

[0122] If the entry is not missing (meaning the entry has been stored), the entry is used by the user device and no SRS scan is required. If the entry is missing, then at block 2, it is determined whether there is an interpolation / extrapolation entry with sufficient confidence in the extended data set 100', and if so, the interpolation / extrapolation entry is used by the user device and no SRS scan is required. If the entry is missing and it is determined that there is no interpolation / extrapolation entry with sufficient confidence, then SRS scan is required and the LSTM 110 is updated with the antenna configuration for the current operating conditions.

[0123] The proposed autonomous [bit-1] UE 20 LSTM based model is summarized below: 1. In the case of an SRS scan event, the relevant operating conditions of the beam corresponding parameters that lead to the request for SRS scan are identified; and the corresponding UE 20 transmission settings are updated and stored.

[0124] 2. The updated transmit beam configuration will be used to optimize the user equipment 20 performance, and it will enter the LSTM neural network as the input layer. This condition can occur after a sufficient number of SRS scanning events ( Figure 7 1).

[0125] 3. When possible / necessary, an interpolation method (e.g., spline interpolation or linear interpolation) is applied to estimate neighboring entry conditions. This interpolation can be applied to any matrix ( Figure 7 3).

[0126] 4. The non-interpolated, interpolated and extrapolated entries of the corresponding parameters of the multidimensional beam are used as the input layer of the conventional LSTM neural network.

[0127] 5. As the neural network builds its knowledge of the processed training data, interpolated and extrapolated entries can be updated and predicted more accurately.

[0128] 6. With box 3 completed, the user equipment 20 can reduce the number of SRS scans actually requested. It can also follow a pattern based on previous knowledge of successful / unsuccessful Tx (transmit) beam configurations across different parameters. Based on previous knowledge, [Bit-0] the user equipment 20 can decide whether SRS scanning is required.

[0129] Therefore, the LSTM model exploits dynamic / partial correspondence to optimize SRS scan requests.

[0130] Figure 8 An example of a method performed by the user equipment 20 is schematically illustrated.

[0131] At block 200, user equipment 20 determines its current operating conditions.

[0132] At block 210, the user equipment 20 determines whether there is an antenna configuration entry for the current operating conditions in its data set.

[0133] If so, then at block 220, the user equipment uses that antenna configuration.

[0134] At block 230 , it is determined whether the network has been notified that the user equipment 20 is operating as a [bit-1] user equipment 20 .

[0135] If so, processing returns to block 200 .

[0136] Otherwise, at block 240 the user equipment 20 signals to the network that the user equipment 20 is operating as a [bit-1] user equipment 20 while remaining in the RRC_connected mode and the process returns to block 200 .

[0137] If it is determined at block 210 that the user equipment does not have an antenna configuration entry for the current operating conditions in its data set, then at block 250 it is determined whether the network has been notified that the user equipment 20 is operating as a [bit-0] user equipment 20 .

[0138] If so, processing continues to block 260 .

[0139] Otherwise, at block 270 the user equipment 20 signals to the network that the user equipment 20 is operating as a [bit-0] user equipment 20 while remaining in the RRC_connected mode and processing continues to block 260 .

[0140] At block 260, the user equipment 20 signals the network that it needs to perform an SRS scan.

[0141] At block 265, the antenna configuration for the current conditions determined by the SRS scan is applied.

[0142] At block 280 , the antenna configuration for the current conditions is provided to the LSTM 110 , the data set is updated and processing returns to block 200 .

[0143] Figure 7 The blocks shown in the figure may represent steps in the method and / or code segments in the computer program. The description of the specific order of the blocks does not necessarily imply that there is a required or preferred order for the blocks, and the order and arrangement of the blocks may be variable. In addition, it is possible that some blocks are omitted.

[0144] Thus, it can be seen that some embodiments limit SRS overhead by identifying only scenarios where beam mismatch is likely and learning to associate operating conditions with beam realignment, so as to reduce the need for SRS beam scanning in a timely manner and aim to be a [bit-1] user device 20. This has the significant advantage of potentially reducing the calibration burden when the user device 20 is produced, because the user device 20 can come out of the factory in a state that is only compatible with the specification but not compatible with the beam correspondence; the user device 20 can learn beam correspondence compatibility in practice (in other words, during use by the user of the user device); each user device 20 can save hundreds of millions of air tests. This makes it possible to have [bit-1] user devices 20 on the market, which would otherwise be unrealistic because of the time and money required for air testing. Both lookup tables and machine learning can be used for this process. The scanned beam can be learned from a lookup table or LSTM. Nonetheless, there are significant gains from using machine learning instead of lookup tables: using machine learning (and neural networks) the user device 20 can reach beam correspondence as quickly as possible; the user device 20 can use interpolation and LSTM refinement to predict missing data so that it can configure its transmit beam using the interpolated data instead of requesting an SRS scan; dynamic / partial beam correspondence can be used to improve the accuracy of SRS scan requests; the user device 20 can establish an SRS scanning pattern based on the learned settings; the user device 20 can request a specific (reduced) number of SRS resources based on neighboring conditions and neighboring updated user device 20 transmit beam configurations to optimize resource allocation.

[0145] Those skilled in the art will readily recognize that the blocks of the various above-described methods can be performed by a programmed computer. Some embodiments herein are also intended to encompass program storage devices, such as digital data storage media, which are machine or computer readable and encode a machine executable or computer executable program of instructions, wherein the instructions perform some or all of the blocks of the above-described methods. The program storage device can be, for example, a digital memory, a magnetic storage medium such as a disk and tape, a hard drive, or an optically readable digital data storage medium. Embodiments are also intended to encompass computers programmed to perform the blocks of the above-described methods.

[0146] The user equipment 20 may be any of the following: a portable electronic device with cellular protocol capabilities, a terminal, a laptop computer, a tablet computer, a body or wrist worn electronic device, a handheld electronic navigation device, and the like.

[0147] Fig. 9 Some components of the user equipment 20 are illustrated in detail. It should be understood that Figures 1 to 8 Each block in the description may be implemented by various components or a combination thereof, such as hardware, software, firmware, one or more processors, and / or circuit systems.

[0148] The user device 20 may include at least one processor or control unit or module 511. At least one memory 512 may be provided in each device. The memory 512 may include computer program instructions or computer code contained therein. One or more radio frequency circuit systems 513 may be provided, and each device may also include an antenna 514. Although only one antenna 514 is shown, many antennas and multiple antenna elements may be provided to each device. For example, other configurations of these devices may be provided. For example, in addition to wireless communication, the user device 20 may be additionally configured for wired communication, and in this case, the antenna 514 may show any form of communication hardware without being limited to an antenna.

[0149] The radio frequency circuitry 513 may independently be a transmitter, a receiver, or both a transmitter and a receiver, or may be a unit or device that may be configured for both transmission and reception.

[0150] The user device 20 may be a mobile station (MS), such as a mobile phone or smart phone or a multimedia device, an IoT cellular device, a computer, such as a tablet computer providing wireless communication capabilities, a personal data or digital assistant (PDA) providing wireless communication capabilities, a portable media player, a digital camera, a pocket camera, a navigation unit providing wireless communication capabilities, or any combination thereof. In other embodiments, the user device may be replaced by a machine communication device that does not require any human-machine interaction, such as a sensor, an instrument, or a robot.

[0151] In some embodiments, the user equipment 20 may include components for performing the above embodiments. In some embodiments, at least one memory 512 including computer program code may be configured to use at least one processor 511 to cause the user equipment 20 to at least perform any of the processes described herein.

[0152] The processor 511 may be implemented by any computing or data processing device, such as a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), a digital enhancement circuit, or an equivalent device or a combination thereof. The processor(s) 511 may be implemented as a single controller, or multiple controllers or processors.

[0153] For firmware or software, the implementation may include modules or units (e.g., programs, functions, etc.) of at least one chipset. Memory 512 may independently be any appropriate storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other appropriate memory may be used. The memory may be combined on a single integrated circuit as a processor, or may be separated from it. In addition, computer program instructions may be stored in memory 512, and any suitable form of computer program code (e.g., a compiled or interpreted computer program written in any suitable programming language) may be processed by (multiple) processors 511. Memory 512 or data storage entities are typically internal, but may also be external or in a combination thereof, such as when additional memory capacity is obtained from a service provider. Memory 512 may be fixed or removable.

[0154] The memory 512 and the computer program instructions may be configured to, together with the processor(s) 511, cause the user device 20 to perform any of the processes described above. Thus, in some embodiments, the non-transitory computer-readable medium may be encoded with computer instructions or one or more computer programs (such as added or updated software routines, applets, or macros) that, when executed in hardware, may perform a process such as one of the processes described herein. The computer program may be encoded in a programming language, which may be a high-level programming language (such as objective-C, C, C++, C#, Java, etc.), or a low-level programming language (such as machine language, or assembler). Alternatively, some embodiments may be fully implemented in hardware.

[0155] Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed.

[0156] Features described in the preceding description may be used in combinations other than those explicitly described.

[0157] Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

[0158] Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.

[0159] While an effort has been made in the foregoing description to call attention to those features of the present invention regarded as particularly important, it will be understood that the applicants claim protection for any patentable feature or combination of features mentioned above and / or shown in the drawings, whether or not particular emphasis has been placed thereon.

Claims

1. A method for communication, comprising: determining, at the user equipment, a current operating condition of the user equipment; dynamically identifying whether the user equipment has stored in the data set an antenna configuration entry for the current operating condition of the user equipment, wherein the antenna configuration entry is associated with an antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment; In response to failing to identify the antenna configuration in the data set, performing a reference signal scanning process for the user equipment current operating condition to identify the antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment, wherein the reference signal scanning process includes at least a sounding reference signal (SRS) scan for uplink beam alignment; as well as In response to identifying the antenna configuration in the data set, applying the antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment.

2. The method according to claim 1, comprising: When no antenna configuration entry is identified, it is signaled that for the current operating condition of the user equipment, a reference signal scanning process is required to identify an antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment.

3. The method of claim 1, comprising storing the antenna configuration identified by the reference signal scanning process for current operating conditions of the user equipment.

4. The method of claim 1, comprising preventing storage of the antenna configuration identified by the reference signal scanning process for a current operating condition of the user equipment when a predetermined condition occurs. The method of claim 4 , wherein the predetermined condition indicates that the user equipment operates in a non-repeatable manner.

6. The method of claim 1, comprising storing the antenna configuration with an additional operating condition when an at least partially repeatable change in a condition of the user equipment is detected.

7. The method according to claim 1, comprising at least one of the following: interpolating at least one antenna configuration for maintaining beam correspondence between a user equipment transmit beam and a receive beam for other user equipment operating conditions using the antenna configuration for the user equipment current operating condition and at least one other stored antenna configuration; and The antenna configuration for the current operating condition of the user equipment and at least one other stored antenna configuration are used to extrapolate at least one antenna configuration for maintaining beam correspondence between a user equipment transmit beam and a receive beam for other user equipment operating conditions.

8. The method of claim 7, comprising storing at least one of: interpolated antenna configurations for the other user equipment operating conditions; and An extrapolated antenna configuration for the other user equipment operating conditions.

9. The method according to claim 1, comprising at least one of the following: recursively recalculating antenna configurations for maintaining beam correspondence between a user equipment transmit beam and a receive beam for other user equipment operating conditions using at least one of the interpolated antenna configuration and the extrapolated antenna configuration; and The antenna configuration identified by the reference signal scanning process is used to recursively recalculate antenna configurations for maintaining beam correspondence between a user equipment transmit beam and a receive beam for other user equipment operating conditions.

10. A method according to any preceding claim, comprising dynamically providing an indication to a network node whether the user equipment is capable of maintaining a beam correspondence between a user equipment transmit beam and a receive beam for current operating conditions of the user equipment.

11. The method of claim 10, wherein the dynamically providing comprises at least one of: providing a change in the indication when the user equipment switches between an antenna configuration stored by the user equipment for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment identified for a current operating condition of the user equipment and an antenna configuration stored by the user equipment for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment not identified for a current operating condition of the user equipment; and The change in the indication is provided while remaining in a radio resource control connected mode.

12. The method of claim 11, wherein the indication indicates at least one of the following: When the antenna configuration is identified as being stored by the user equipment for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment for the current operating condition of the user equipment, the user equipment is of a type that supports autonomous beam correspondence; and When the antenna configuration is not identified for the current operating condition of the user equipment as being stored by the user equipment for maintaining beam correspondence between the user equipment transmit beam and the receive beam, the user equipment is of a type requiring network support for beam correspondence.

13. A computer program product comprising instructions for causing an apparatus to at least perform the following operations: determining, at the user equipment, a current operating condition of the user equipment; dynamically identifying whether the user equipment has stored in the data set an antenna configuration entry for the current operating condition of the user equipment, wherein the antenna configuration entry is associated with an antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment; In response to failing to identify the antenna configuration in the data set, performing a reference signal scanning process for the user equipment current operating condition to identify an antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment, wherein the reference signal scanning process includes at least a sounding reference signal (SRS) scan for uplink beam alignment; as well as In response to identifying the antenna configuration in the data set, applying the antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment.

14. An apparatus for communication, comprising: means for determining, at said apparatus comprising user equipment, a current operating condition of the user equipment; A component for dynamically identifying whether the user equipment stores an antenna configuration entry for a current operating condition of the user equipment in a data set, wherein the antenna configuration entry is associated with an antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment; means for performing a reference signal scanning process for a current operating condition of the user equipment to identify an antenna configuration for maintaining beam correspondence between a transmit beam and a receive beam of the user equipment in response to a failure to identify the antenna configuration in the data set, wherein the reference signal scanning process comprises at least a sounding reference signal (SRS) scan for uplink beam alignment; as well as Means for applying the antenna configuration for maintaining beam correspondence between transmit beams and receive beams of the user equipment in response to identifying the antenna configuration in the data set.

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