WO2024094293A1

WO2024094293A1 - Radio node and method in a communications network

Info

Publication number: WO2024094293A1
Application number: PCT/EP2022/080487
Authority: WO
Inventors: Martin Alm; Bo Göransson
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2022-11-02
Filing date: 2022-11-02
Publication date: 2024-05-10

Abstract

A method performed in a first radio node is provided. The method is for handling beam squint in any one out of: a transmission or reception, between the first radio node and a second radio node in a communications network. A Grid of Beam, GoB, codebook comprising Beam Indexes, Bls, indicating beam vectors designed for a reference carrier frequency (f0) is defined for said transmission or reception. The first radio node obtains (801) for said transmission or reception, measurements of reference signals related to the second radio node. The frequency of the reference signals is part of a first carrier frequency (f1). The first radio node identifies (802) a Bl for the second radio node at the first carrier frequency (f1). The Bl is indicating a best beam vector with a best signal quality among the Bls in the GoB codebook. The identifying is based on the obtained reference signal measurements, and the GoB codebook. The first radio node then calculates (803) a beam squint based on the best beam vector, and the GoB codebook. Based on the calculated beam squint and the GoB codebook, the first radio node decides (805) for a second carrier frequency (f2) to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint.

Description

RADIO NODE AND METHOD IN A COMMUNICATIONS NETWORK

TECHNICAL FIELD

Embodiments herein relate to a network node and a methods therein. In some aspects, they relate to handling beam squint in a transmission or reception, between a first radio node and a second radio node in a communications network.

BACKGROUND

In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and/or User Equipment (UE), communicate via a Wide Area Network or a Local Area Network such as a Wi-Fi network or a cellular network comprising a Radio Access Network (RAN) part and a Core Network (CN) part. The RAN covers a geographical area which is divided into service areas or cell areas, with each service area or cell area being served by a radio network node such as a radio access node e.g., a Wi-Fi access point, a Base Station (BS) or a radio base station (RBS), which in some networks may also be denoted, for example, a Base Station (BS), a NodeB, eNodeB (eNB), or gNodeB (gNB) as denoted in Fifth Generation (5G) telecommunications. A service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node communicates over an air interface operating on a radio frequency with the wireless devices within the range of the radio network node.

3rd Generation Partnership Project (3GPP) is the standardization body for specifying the standards for the cellular system evolution, e.g., including 3G, 4G, 5G and the future evolutions. Specifications for Evolved Universal Terrestrial Radio Access (E- UTRA) and Evolved Packet System (EPS) have been completed within the 3GPP. In 4G also called a Fourth Generation (4G) network, EPS is core network and E-UTRA is radio access network. In 5G, 5GC is core network, NR is radio access network. As a continued network evolution, the new release of 3GPP specifies a 5G network also referred to as 5G New Radio (NR) and 5G Core (5GC).

Frequency bands for 5G NR are being separated into two different frequency ranges, Frequency Range 1 (FR1) and Frequency Range 2 (FR2). FR1 comprises sub-6 GHz frequency bands. Some of these bands are bands traditionally used by legacy standards but have been extended to cover potential new spectrum offerings from 410 MHz to 7125 MHz. FR2 comprises frequency bands from 24.25 GHz to 52.6 GHz. Bands in this millimeter wave range have shorter range but higher available bandwidth than bands in the FR1.

Multi-antenna techniques may significantly increase the data rates and reliability of a wireless communication system. For a wireless connection between a single user, such as UE, and a base station (BS), the performance is in particular improved if both the transmitter and the receiver are equipped with multiple antennas, which results in a Multiple-Input Multiple-Output (MIMO) communication channel. This may be referred to as Single-User (SU)-MIMO. In the scenario where MIMO techniques is used for the wireless connection between multiple users and the base station, MIMO enables the users to communicate with the base station simultaneously using the same time-frequency resources by spatially separating the users, which increases further the cell capacity. This may be referred to as Multi-User (MU)-MIMO. Note that MU-MIMO may benefit when each UE only has one antenna. The cell capacity can be increased linearly with respect to the number of antennas at the BS side. Due to that, more and more antennas are employed in BS. Such systems and/or related techniques are commonly referred to as massive MIMO.

5G NR may be used for so-called millimeter wave (mmWave) or FR2 frequency bands. The mmWave or FR2 frequency bands may be found in ,24.25GHz -52.6GHz. frequency range. The benefit of defining these bands with high carrier frequency is the availability of large bandwidths. The drawback is a higher pathloss that is experienced on mmWave frequencies. One way to overcome this increased pathloss is to apply a large antenna array and to introduce beamforming. By this the Equivalent Isotropic Radiated Power (EIRP) and Equivalent Isotropic Sensitivity (EIS) can be kept high without increasing the radiated power too much.

Figure 1 shows a simple illustration of an antenna array using beamforming.

To realize a beamforming system the signal transmitted on each element should be time shifted in relation to the adjacent element 11. From Error! Reference source not found, it is evident that the delay between two adjacent elements 11 should be T if the signal should be tilted towards 9 from a broad side 12 direction 13 to the tilted directions. Some simple geometry then gives T = ^sin (0) where c is the speed of light and d is the distance between two adjacent elements 11. For a narrow band signal, the time delay is equivalent to phase shifting since

and hence beamforming may be implemented by phase shifting the signal between the elements. From this it is further evident that the phase <|) is dependent on the frequency or The amount of phase shifting between elements will decide the direction of the beam for a certain frequency. Since c = Af the time delay between two elements T = ^~ sin (0) can be converted to a phase shift given by is dependent on the wavelength A of the carrier frequency.

When a large bandwidth is supported in a system with beamforming, the frequency dependency of the beam pointing direction may be problematic. A beam defined for a certain frequency will point in a slightly different direction when applied at another frequency. This effect is usually referred to as beam squint. Beam squint may mean an unfocusing of an antenna across frequency when phase shift is used instead of a true time delay, to steer a beam.

SUMMARY

As a part of developing embodiments herein a problem was identified by the inventors and will first be discussed.

Figure 2 shows a typical case of beam squint for an antenna system operating at the 26GHz frequency band. The beams are designed at a certain frequency, say fo=26GHz, referred to as dashed curve in the figure, but applied at a carrier frequency of fi=27.6GHz referred to as solid curve in the figure. It is noted that the beam squint is dependent on the tilt, also referred to as steering angle of the beam, and that the beam squint increases with the steering angle. In this particular case, the beamwidth is around 3.5° while the beam squint for a beam steered towards 60° experience a beam squint of 5°.

A general formula can easily be derived from the expression of the phase shift between any two elements

The beam angle 0 is given by 0 =

A and hence the beam squint can be expressed as

The beam squint is a function of frequency and steering angle. The beam squint is symmetrical around broad side (0=0°) and is growing with frequency offset to the frequency used to design the beam, but also to the steering angle of the beam. Error! Reference source not found, shows the beam squint problem for steering angle and frequency offset.

Beamforming for an FR2 system is mainly implemented with so-called codebooks. This means that a beamforming vector is precalculated and stored in a Look-Up Table (LUT), and may be indexed by a single parameter, a Beam Index (Bl). To keep the LUT small, the beam weights are calculated for a specific frequency, but then used for all carriers within the band. Beam weights when used herein e.g. means an amplitude and phase value that should be applied to the signal before transmitted on the antenna such as e.g. amplitude and phase settings for all the antenna elements designed to steer the beam to a specific direction. A typical example of beam layout for a typical FR2 radio product is shown in Figure 4. The beam pointing directions of a primary service area are shown for a two-dimensional case.

The beams for one row are depicted in Figure 5. Figure 5 shows an example of beams covering one horizontal slice of Figure 4. A similar arrangement can be envisioned for the vertical domain.

The problem of using a beamforming vector designed for one carrier frequency fO, on another frequency ‘f’ is the drop in gain due to beam squint. For a large array supporting a wide bandwidth this gain drop due to beam squint can be substantial as shown in Figure 6. In this example, the gain drop due to beam squint is shown for a 24- element array for a source located at 20° relative to a broadside. Note that the gain drop would be much larger when the beam is steered to larger angles such as e.g. towards end-fire. An end-fire when used herein e.g. means steering towards 90° relative to broadside. E.g., for a beam steered to 40 degrees the gain drop would be more than 3dB.

An object of embodiments herein is to improve the performance in a communications network. According to an aspect of embodiments herein, the object is achieved by a method performed in a first radio node for handling beam squint in any one out of: a transmission or reception, between the first radio node and a second radio node in a communications network. A Grid of Beam, GoB, codebook comprising Beam Indexes, Bls, indicating beam vectors designed for a reference carrier frequency (fO) is defined for said transmission or reception. The first radio node obtains (201) for said transmission or reception, measurements of reference signals related to the second radio node. The frequency of the reference signals is part of a first carrier frequency (f1). The first radio node identifies (202) a Bl for the second radio node at the first carrier frequency (f1). The Bl is indicating a best beam vector with a best signal quality among the Bls in the GoB codebook. The identifying is based on the obtained reference signal measurements, and the GoB codebook. The first radio node then calculates (203) a beam squint based on the best beam vector, and the GoB codebook. Based on the calculated beam squint and the GoB codebook, the first radio node decides (205) for a second carrier frequency (f2) to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint.

According to another aspect of embodiments herein, the object is achieved by a first radio node. The first radio node is configured to handle beam squint in any one out of: a transmission or a reception between the first radio node and a second radio node in a communications network. A Grid of Beam, GoB, codebook comprising Beam Indexes, Bls, indicating beam vectors designed for a reference carrier frequency (fO) is adapted to be defined for said transmission or reception. The first radio node further being configured to:

- obtain for said transmission or reception, measurements of reference signals related to the second radio node, which frequency of the reference signals is part of a first carrier frequency (f1),

- identify for the second radio node at the first carrier frequency (f 1 ) , a Bl indicating a best beam vector with a best signal quality among the Bls in the GoB codebook, which identifying is based on the obtained reference signal measurements, and the GoB codebook,

- calculate a beam squint based on the best beam vector, and the GoB codebook, and

- based on the calculated beam squint and the GoB codebook, decide for a second carrier frequency (f2) to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint.

Embodiments herein e.g., provide the following advantages:

An advantage achieved from the beam squint compensation is that a higher gain may be obtained than if an “original” beam vector is used on a frequency carrier located far from the frequency carrier where the beam vector is defined.

Another advantage is that the same LUT may be used for all frequency carriers and hence memory is saved compared to the case when the GoB is carrier specific.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of embodiments herein are described in more detail with reference to attached drawings in which:

Figure 1 is a schematic diagram illustrating prior art.

Figure 2 is a schematic diagram illustrating prior art.

Figure 3 is a schematic diagram illustrating prior art.

Figure 4 is a schematic diagram illustrating prior art.

Figure 5 is a schematic diagram illustrating prior art.

Figure 6 is a schematic diagram illustrating prior art.

Figure 7 is a schematic block diagram illustrating embodiments of a wireless communications network.

Figure 8 is a flowchart depicting an embodiment of a method in a first radio node.

Figure 9 is a diagram illustrating an example scenario of embodiments herein.

4 is a diagram illustrating an example scenario of embodiments herein.

Figure 11 is a schematic block diagram illustrating embodiments of a first radio node.

Figure 12 schematically illustrates a telecommunication network connected via an intermediate network to a host computer.

Figure 13 is a generalized block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection.

Figures 14-17 are flowcharts illustrating methods implemented in a communication system including a host computer, a base station, and a user equipment. DETAILED DESCRIPTION

Examples of embodiments herein relate to Beam squint compensation.

To overcome the problem with a gain drop due to beam squint, examples of embodiments herein provide a method wherein a first radio node compensates for a squint by selecting a beam index per carrier which compensates for the squint. For example, assume that the system has identified a certain Bl at a frequency f1 and fO is the frequency where the codebook has been defined. The beam squint may now be calculated for all used carriers in relation to fO, and a codebook vector better matching this beam squint can be selected for a carrier f2.

According to embodiments herein, if the codebook has been defined on a certain reference frequency, say fO, but the best beam is identified at f1 , the beam squint for a third frequency, say f2, will to be compensated for the frequency shift f0-f2.

As mentioned above, an advantage achieved from the beam squint compensation according to embodiments herein, is that a higher gain is obtained than if the “original” beam vector is used on a carrier frequency located far from the carrier frequency where the beam vector is defined.

Yet another advantage is that measurements to find “best” beam may be performed on any frequency regardless of the frequency that was used to define the GoB, but still provide a beam with high gain pointing towards the second radio node.

Figure 7 is a schematic overview depicting a communications network 100, such as e.g. a wireless communications network, wherein embodiments herein may be implemented. The communications network 100 comprises one or more RANs and one or more CNs. The communications network 100 may use 5G NR but may further use a number of other different technologies, such as, 6G, Wi-Fi, (LTE), LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/enhanced Data rate for GSM Evolution (GSM/EDGE), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations.

Radio nodes, such as a first radio node 110, operate in the communications network 100. The first radio node 110 e.g. provides a number of cells and may use these cells for communicating with other radio nodes, such as e.g. a second radio node 120 which may be a UE. The first radio node 110 may be a transmission and reception point e.g. a network node, a radio access network node such as a base station, a radio base station, a NodeB, an evolved Node B (eNB, eNodeB, eNode B), an NR/g Node B (gNB), a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a transmission arrangement of a radio base station, a stand-alone access point, a Wireless Local Area Network (WLAN) access point, an Access Point Station (AP STA), an access controller, a UE acting as an access point or a peer in a Device to Device (D2D) communication, or any other network unit capable of communicating with a UE served by the first radio node 110 depending e.g. on the radio access technology and terminology used.

In some embodiments herein, the first radio node 110 may be a UE.

Radio nodes, such as the second radio node 120, operate in the communications network 100. The second radio node 120 may e.g. be a UE, an NR device, a mobile station, a wireless terminal, an NB-loT device, an enhanced Machine Type Communication (eMTC) device, an NR RedCap device, a CAT-M device, a Vehicle-to- everything (V2X) device, Vehicle-to-Vehicle (V2V) device, a Vehicle-to-Pedestrian (V2P) device, a Vehicle-to-lnfrastructure (V2I) device, and a Vehicle-to-Network (V2N) device, a Wi-Fi device, an LTE device and a non-access point (non-AP) STA, a STA, that communicates via a base station such as e.g. the network node 110, one or more Access Networks (AN), e.g. RAN, to one or more core networks (CN). It should be understood by the skilled in the art that the term UE relates to a non-limiting term which means any UE, terminal, wireless communication terminal, user equipment, (D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station communicating within a cell.

In some embodiments herein, the second radio node 120 may be a radio network node such as a gNB.

Thus, the first radio node 110 may be represented by a radio network node such as e.g. gNB, and the second radio node 120 is represented by a User Equipment, UE. This is shown in Figure 7 In some embodiments it may be the other way around, the first radio node 110 is represented by a UE and the second radio node 120 is represented by a radio network node such as e.g. a gNB. Methods herein may in one aspect be performed by the first radio node 110. As an alternative, a Distributed Node (DN) and functionality, e.g. comprised in a cloud 135 as shown in Figure 7, may be used for performing or partly performing the methods of embodiments herein.

Examples of embodiments herein e.g. provides a method wherein a GoB codebook is defined for a certain carrier frequency fO.

The “best” beam vector for a second radio node 120, e.g. a UE, is identified by the first radio node 110 on a particular measurement frequency f1 , for example, based on Channel State Information - Reference Signals (CSI-RS) feedback or Sounding Reference Signal (SRS) measurements.

The first radio node 110 calculates the beam squint based on the carrier frequency where the GoB codebook has been defined, fO, the “best” beam vector identified at measurement frequency f1, and the carrier frequency f2 where it should be used for transmission or reception of data.

The first radio node 110 identifies if there is a different Bl from the codebook that provides higher gain at this serving carrier frequency f2. To compensate for the beam squint, use this beam instead.

A number of embodiments will now be described, some of which may be seen as alternatives, while some may be used in combination.

Figure 8 shows exemplary embodiments of a method performed by the first radio node 110. The method is for handling beam squint in any one out of: a transmission or reception, between the first radio node 110 and a second radio node 120 in a communications network 100. This e.g. means that the method is for handling beam squint in a transmission between, i.e. in any of DL and UL, the first radio node 110 and a second radio node 120, or for handling beam squint in a reception, i.e. in any of DL and UL, between the first radio node 110 and a second radio node 120. In other words the method relates to transmitting in DL and UL and receiving in DL and UL.

The first radio node 110 may be represented by a radio network node and the second radio node 120 is represented by a User Equipment, UE. In some embodiments it may be the other way around, the first radio node 110 is represented by a UE and the second radio node 120 is represented by a radio network node.

A Grid of Beam (GoB) codebook comprising Beam Indexes (Bl)s is defined for said transmission or reception. The Bls indicate beam vectors designed for a reference carrier frequency fO. Thus each Bl may indicate one beam vector.

The method comprises the following actions, which actions may be taken in any suitable order.

Action 801

The first radio node 110 obtains measurements of reference signals for said transmission or reception. The measurements of reference signals are related to the second radio node 120. The frequency of the reference signals is part of a first carrier frequency f1.

The measurements of reference signals may e.g. relate to CSI-RS feedback or SRS measurements The measurements of reference signals may be obtained by the first network node 110 making the measurements itself or by receiving the measurement in a report from e.g., the second radio node 120.

Action 802

The first radio node 110 identifies a Bl for the second radio node 120 at the first carrier frequency f1. This may be since frequency of the measured reference signals is part of a first carrier frequency f1. The identified Bl indicates a beam vector referred to as the best beam vector. The best beam vector is the beam vector with the best signal quality among the Bls in the GoB codebook. The identifying is based on the obtained reference signal measurements at the first carrier frequency f1. The identifying is further based on the GoB codebook designed for the reference carrier frequency fO.

Action 803

Thus the GoB codebook defined for the reference carrier frequency fO have been used for identifying the best beam vector based on the obtained reference signal measurements at the first carrier frequency f1. This may result in a beam squint that may need to be compensated for in carrier frequencies to be used for said transmission or reception. The first radio node 110 calculates a beam squint based on the best beam vector at the first carrier frequency f1 and the GoB codebook for beamforming in the reference carrier frequency fO. Action 804

In some embodiments, the first radio node 110 decides how close to the beam intersection direction between two beams the direction from which the reference signal of the second radio node 120 appears to be coming from based on: measured signal quality in adjacent beam vectors relative to best beam vector at the first carrier frequency f1 . This will be further explained below.

The beam intersection direction may also referred to as beam cross-over direction. It is not always the geographical direction but rather the direction from which the signal appears to be coming from. E.g. not the same in Non-Line-Of-Sight (NLOS).

Action 805

Based on the calculated beam squint and the GoB codebook for beamforming in the reference carrier frequency fO, the first radio node 110 decides for a second carrier frequency f2 to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint. The transmission or reception may be performed on several frequencies, the first carrier frequency f1 , and in this example also the second carrier frequency f2.

In some embodiments, the deciding may further is based on how close to the beam intersection direction, between two beams the direction from which the reference signal of the second radio node 120 appears to be coming from.

In this way, a beam vector for the second carrier frequency f2 with higher signal quality than the best beam vector at the first carrier frequency f1 it is achieved.

In some embodiments, the deciding for the second carrier frequency f2 for said transmission or reception further comprises: Deciding for the rest of all respective of the carrier frequencies f3-fn to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint, related to each of the carrier frequencies f3-fn. Also in these embodiments, the deciding may further be based on how close to the beam intersection direction, between two beams the direction from which the reference signal of the second radio node 120 appears to be coming from.

Whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint may be performed to any one or more out of:

- Select a beam vector for the second carrier frequency f2 with higher signal quality than the best beam vector at the first carrier frequency f1 , and - Select a beam vector for the rest of all respective carrier frequencies f3-fn with higher signal quality than the best beam vector at the first carrier frequency f1.

Embodiments herein such as the embodiments mentioned above will now be further described and exemplified. The text below is applicable to and may be combined with any suitable embodiment described above.

Table 1 illustrates an example of a GoB codebook comprising a weight matrix for an eight-element array with eight beams. The term weight when used herein for a matrix may mean the complex coefficients Wmn applied to the antenna ports. The argument of the coefficients is such that a progressive phase increase is achieved across the ports. This will make the signals from the antenna elements add up in phase in a certain spatial direction. The greater the phase shift is between elements, the greater the steering angle will be from broadside. A broadside when used herein e.g. means a beam in the normal direction of the array antenna In the Table 1 it is assumed that BI1 is a broadside beam, and that the pointing direction of the beams increase with increasing Bl.

Table 1

As described above, the best beam out of the beams in the GoB is found by e.g. detecting a sounding signal from the second radio node 120, e.g. a UE. The sending of the reference signals, also referred to as sounding, may be performed for a narrow frequency bandwidth but the transmission or reception of the data channel is done for a wide bandwidth. The wide bandwidth is divided into frequency blocks, so called Component Carriers (CC). Since the squint of the beams is a deterministic function of frequency and steering angle a beam index offset table may be defined. This table may be used to squint compensate the Bl found for a sounding frequency to other frequencies. Table 2 shows an example.

For example, for small frequency offsets and/or small steering angles the beam squint is small, and the Bl of the sounding frequency should be unchanged. For larger frequency offsets and steering angles, higher Bl in Table 1, an adjustment of Bl should be made according to the defined table, e.g. Table 2. see also Figure 6.

Consider the following example and see Table 2: The second radio node 120, e.g. a UE, sends a reference signal, also referred to as a sounding signal, which frequency is part of CCO. BI7 is detected by the first radio node 110, e.g. a base station to be the best beam choice at this frequency. The transmission to the second radio node 120, e.g. the UE, is intended to extend over the CCs 0-4. The Table 2 reveals that for CCO-2, BI7 should be used. At CC3-4, BI8 should be used instead since it provides higher antenna gain. Note that if the second radio node 120, e.g. the UE is in an outer beam, such as e.g. BI8, there is no beam that can be changed to for positive frequency offsets. Hence the “N/A” in the Table 2.

Table 2

Additional embodiments

As described above, it is assumed that the source, i.e. the second radio node 120, e.g. a UE, sending the reference signal, is located close to a peak-of-beam in the angular domain. In some example scenarios this assumption may not hold in some situations. Figure 9 is a diagram depicting the beam angle in degrees (X-axis) vs. the beam gain in dB Y-axis. Figure 9 illustrates a best beam 910 indicated by bold according to a GoB codebook. The direction towards the source is indicated by the black vertical dashed line 900 and illustrates the example scenarios mentioned above. Figure 9 shows a close up of the beams around a source at the angle 0=17°, which is not at peak-of-beam.

Assuming a Line of Sight (LoS) channel, the best beam 910, marked in bold will be selected. In such a case it is evident that the beam compensation described above needs some tweaking. This is since very little negative beam squint is required before the beam to the right is a more optimal choice, but much positive beams squint is required before the beam to the left is optimal. Negative beam squint means that the beams move to lower steering angle which is a consequence of positive frequency offset. Positive beam squint means that the beams move to higher steering angle which is a consequence of negative frequency offset. The frequency shift needed before compensating for beam squint will be different depending on where on the beam the UR is located. Hence it is an advantage to know if the source is close to a neighboring beam or closer to the beam peak 900.

One way of detecting the distance to next beam would be to measure the power in adjacent beams relative to the selected beam. It is possible to judge if the source is close to an adjacent beam or not. Figure 10 depicts received, normalize, power levels of best beam and adjacent beams. Figure 10 shows the received power in a few beams from a source, i.e. the second radio node 120, e.g. a UE sending the reference signal, indicated by black vertical line 1000, at a certain location. The beam with the most received power will be selected as best beam. The power difference in different beams is indicated by circles in the figure. In this particular example, it is noted that the power difference between the best beam and the second-best beam is less than one dB, the difference between two top circles. The power difference between the best beam and the neighboring beam in the opposite direction is much larger, here approximately 4dB. By this it is evident the second radio node 120, e.g. a UE, sending the reference signal, is located close to beam “best+1”, and further away from beam “best-1”,. This may also be seen in Figure 9 where it is evident that the source is at a larger angle than the peak of the selected beam.

The power difference between neighboring beams may be tabulated and then used to establish where in a beam interval the source is likely located. If the power levels in the surrounding beams are similar, it is likely that the source is located close to peak-of-beam. Or, as in the example shown in Figure 10, if the power level is higher in a neighboring beam the source is located close to that. The below Table 3 may either be constructed by simulations, as in the example above, or populated from measurement done in a chamber. A chamber when used herein e.g., means an antenna measurement facility such as an anechoic chamber.. Note also that Table 3 would be dependent on the actual codebook, and number of elements of the array etc. A table matching the example above may look like below where P means power for a beam index and a beam is indexed from left to right. The measured power level in neighboring beams relative best beam is listed in the table, together with the outcome is listed.

Table 3

Note that it is likely that a discriminator may be based on Machine Learning (ML). An algorithm, e.g., based on a neural network, may be trained with data representing different channel models and used to discriminate between the different outcomes, i.e. , how close to the border between two beams the current second radio node 120, e.g. a UE is located, also referred to as how close to the beam intersection direction or how close to a beam cross-over direction, the direction of the source, i.e., the second radio node 120 is. This information may then then used when finding the appropriate beam squint compensation for a CC other than CC0.

This functionality may be incorporated in a beam index compensation Table 2 by extending it according to Table 4.

Table 4

To perform the method actions above, the first radio node 110 is configured to handle beam squint in any one out of: a transmission or a reception between the first radio node 110 and a second radio node 120 in a communications network 100. A Grid of Beam, GoB, codebook comprising Beam Indexes, Bls, indicating beam vectors designed for a reference carrier frequency fO is adapted to be defined for said transmission or reception.

The first radio node 110 may comprise an arrangement depicted in Figure 11. The UE 120 may comprise an input and output interface 1100 configured to communicate in the communications network 100, e.g., with the second radio node 120. The input and output interface 1100 may comprise a wireless receiver not shown and a wireless transmitter not shown.

The first radio node 110 is further configured to:

- Obtain for said transmission or reception, measurements of reference signals related to the second radio node 120, which frequency of the reference signals is part of a first carrier frequency f1 ,

- Identify for the second radio node 120 at the first carrier frequency f1, a Bl indicating a best beam vector with a best signal quality among the Bls in the GoB codebook, which identifying is based on the obtained reference signal measurements, and the GoB codebook,

- Calculate a beam squint based on the best beam vector, and the GoB codebook, and. - Based on the calculated beam squint and the GoB codebook, decide for a second carrier frequency f2 to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint.

In some embodiments, the first radio node 110 further is configured to decide for the second carrier frequency f2 for said transmission or reception by:

- Deciding for the rest of all respective of the carrier frequencies f3-fn to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint.

Any one or more out of (1) and (2) may further be adapted to be based on how close to the beam intersection direction between two beams the direction from which the reference signal of the second radio node 120 appears to be coming from, wherein (1) and (2) are adapted to comprise:

(1) Decide for the second carrier frequency f2 for said transmission or reception, whether or not to select a beam vector from the code book that compensates for the calculated beam squint,

(2) Decide for the rest of all respective of the carrier frequencies f3-fn for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint.

The first radio node 110 may further being configured to decide how close to the beam intersection direction between two beams the direction from which the reference signal of the second radio node 120 appears to be coming from based on measured signal quality in adjacent beam vectors relative to best beam vector at the first carrier frequency f1.

The whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint may be adapted to be performed to any one or more out of:

- Select a beam vector for the second carrier frequency f2 with higher signal quality than the best beam vector at the first carrier frequency f1 , and

- Select a beam vector for the rest of all respective carrier frequencies f3-fn with higher signal quality than the best beam vector at the first carrier frequency f1. E.g. , the first radio node 110 is represented by a radio network node and the second radio node 120 is represented by a User Equipment, UE, or the first radio node 110 is represented by a UE and the second radio node 120 is represented by a radio network node.

The embodiments herein may be implemented through a respective processor or one or more processors, such as the processor 1110 of a processing circuitry in the first radio node 110 depicted in Figure 11 together with respective computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the first radio node 110. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the respective BS 110 and UE 120.

The first radio node 110 may further comprise a memory 1120 comprising one or more memory units. The memory 1120 comprises instructions executable by the processor in first radio node 110. The memory 1120 is arranged to be used to store e.g., information, indications, data, configurations, communication data, and applications to perform the methods herein when being executed in the first radio node 110.

In some embodiments, a computer program 1130 comprises instructions, which when executed by the at least one processor 1110, cause the at least one processor of first radio node 110 to perform the actions above.

In some embodiments, a carrier 1140 comprises the computer program 1130, wherein the carrier 1140 is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.

Those skilled in the art will appreciate that the units in the described above may refer to a combination of analog and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in the res first radio node 110, that when executed by the respective one or more processors such as the processors described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry ASIC, or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

With reference to Figure 12, in accordance with an embodiment, a communication system includes a telecommunication network 3210, such as a 3GPP-type cellular network, e.g. wireless communications network 100, which comprises an access network 3211, such as a radio access network, and a core network 3214. The access network 3211 comprises a plurality of base stations 3212a, 3212b, 3212c, e.g., the BS 110, such as AP STAs NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 3213a, 3213b, 3213c. Each base station 3212a, 3212b, 3212c, e.g. radio network nodes 141 ,142, is connectable to the core network 3214 over a wired or wireless connection 3215. A first user equipment (UE), e.g. the UE 120, such as a Non-AP STA 3291 located in coverage area 3213c is configured to wirelessly connect to, or be paged by, the corresponding base station 3212c, e.g., the network node 110. A second UE 3292, e.g., any of the one or more second UEs 122, such as a Non-AP STA in coverage area 3213a is wirelessly connectable to the corresponding base station 3212a, e.g., the network node 110. While a plurality of UEs 3291, 3292 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 3212.

The telecommunication network 3210 is itself connected to a host computer 3230, which may be embodied in the hardware and/or software of a standalone server, a cloud- implemented server, a distributed server or as processing resources in a server farm. The host computer 3230 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 3221, 3222 between the telecommunication network 3210 and the host computer 3230 may extend directly from the core network 3214 to the host computer 3230 or may go via an optional intermediate network 3220. The intermediate network 3220 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 3220, if any, may be a backbone network or the Internet; in particular, the intermediate network 3220 may comprise two or more sub-networks (not shown).

The communication system of Figure 12 as a whole enables connectivity between one of the connected UEs 3291 , 3292 and the host computer 3230. The connectivity may be described as an over-the-top (OTT) connection 3250. The host computer 3230 and the connected UEs 3291 , 3292 are configured to communicate data and/or signaling via the OTT connection 3250, using the access network 3211 , the core network 3214, any intermediate network 3220 and possible further infrastructure (not shown) as intermediaries. The OTT connection 3250 may be transparent in the sense that the participating communication devices through which the OTT connection 3250 passes are unaware of routing of uplink and downlink communications. For example, a base station 3212 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 3230 to be forwarded (e.g., handed over) to a connected UE 3291. Similarly, the base station 3212 need not be aware of the future routing of an outgoing uplink communication originating from the UE 3291 towards the host computer 3230.

Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to Figure 13. In a communication system 3300, a host computer 3310 comprises hardware 3315 including a communication interface 3316 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 3300. The host computer 3310 further comprises processing circuitry 3318, which may have storage and/or processing capabilities. In particular, the processing circuitry 3318 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 3310 further comprises software 3311 , which is stored in or accessible by the host computer 3310 and executable by the processing circuitry 3318. The software 3311 includes a host application 3312. The host application 3312 may be operable to provide a service to a remote user, such as a UE 3330 connecting via an OTT connection 3350 terminating at the UE 3330 and the host computer 3310. In providing the service to the remote user, the host application 3312 may provide user data which is transmitted using the OTT connection 3350.

The communication system 3300 further includes a base station 3320 provided in a telecommunication system and comprising hardware 3325 enabling it to communicate with the host computer 3310 and with the UE 3330. The hardware 3325 may include a communication interface 3326 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 3300, as well as a radio interface 3327 for setting up and maintaining at least a wireless connection 3370 with a UE 3330 located in a coverage area (not shown in Figure 13) served by the base station 3320. The communication interface 3326 may be configured to facilitate a connection 3360 to the host computer 3310. The connection 3360 may be direct or it may pass through a core network (not shown in Figure 13) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 3325 of the base station 3320 further includes processing circuitry 3328, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 3320 further has software 3321 stored internally or accessible via an external connection.

The communication system 3300 further includes the UE 3330 already referred to. Its hardware 3335 may include a radio interface 3337 configured to set up and maintain a wireless connection 3370 with a base station serving a coverage area in which the UE 3330 is currently located. The hardware 3335 of the UE 3330 further includes processing circuitry 3338, which may comprise one or more programmable processors, applicationspecific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 3330 further comprises software 3331, which is stored in or accessible by the UE 3330 and executable by the processing circuitry 3338. The software 3331 includes a client application 3332. The client application 3332 may be operable to provide a service to a human or non-human user via the UE 3330, with the support of the host computer 3310. In the host computer 3310, an executing host application 3312 may communicate with the executing client application 3332 via the OTT connection 3350 terminating at the UE 3330 and the host computer 3310. In providing the service to the user, the client application 3332 may receive request data from the host application 3312 and provide user data in response to the request data. The OTT connection 3350 may transfer both the request data and the user data. The client application 3332 may interact with the user to generate the user data that it provides. It is noted that the host computer 3310, base station 3320 and UE 3330 illustrated in Figure 12 may be identical to the host computer 3230, one of the base stations 3212a, 3212b, 3212c and one of the UEs 3291 , 3292 of Figure 12, respectively. This is to say, the inner workings of these entities may be as shown in Figure 13 and independently, the surrounding network topology may be that of Figure 12.

In Figure 13, the OTT connection 3350 has been drawn abstractly to illustrate the communication between the host computer 3310 and the use equipment 3330 via the base station 3320, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 3330 or from the service provider operating the host computer 3310, or both. While the OTT connection 3350 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 3370 between the UE 3330 and the base station 3320 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 3330 using the OTT connection 3350, in which the wireless connection 3370 forms the last segment. More precisely, the teachings of these embodiments may improve the RAN effect: data rate, latency, power consumption and thereby provide benefits such as e.g. the applicable corresponding effect on the OTT service: reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime.

A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 3350 between the host computer 3310 and UE 3330, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 3350 may be implemented in the software 3311 of the host computer 3310 or in the software 3331 of the UE 3330, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 3350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 3311, 3331 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 3350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 3320, and it may be unknown or imperceptible to the base station 3320. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer’s 3310 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 3311, 3331 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 3350 while it monitors propagation times, errors etc.

Figure 14 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to Figure 12 and Figure 13. For simplicity of the present disclosure, only drawing references to Figure 14 will be included in this section. In a first Step 2410 of the method, the host computer provides user data. In an optional sub Step 2411 of the first Step 2410, the host computer provides the user data by executing a host application. In a second Step 2420, the host computer initiates a transmission carrying the user data to the UE. In an optional third Step 2430, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth Step 2440, the UE executes a client application associated with the host application executed by the host computer.

Figure 15 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to Figure 12 and Figure 13. For simplicity of the present disclosure, only drawing references to Figure 15 will be included in this section. In a first Step 2510 of the method, the host computer provides user data. In an optional sub step (not shown) the host computer provides the user data by executing a host application. In a second Step 2520, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third Step 2530, the UE receives the user data carried in the transmission.

Figure 16 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to Figure 12 and Figure 13. For simplicity of the present disclosure, only drawing references to Figure 16 will be included in this section. In an optional first Step 2610 of the method, the UE receives input data provided by the host computer. Additionally or alternatively, in an optional second Step 2620, the UE provides user data. In an optional sub Step 2621 of the second Step 2620, the UE provides the user data by executing a client application. In a further optional sub Step 2611 of the first Step 2610, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in an optional third sub Step 2630, transmission of the user data to the host computer. In a fourth Step 2640 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.

Figure 17 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to Figure 12 and Figure 13. For simplicity of the present disclosure, only drawing references to Figure 17 will be included in this section. In an optional first Step 2710 of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In an optional second Step 2720, the base station initiates transmission of the received user data to the host computer. In a third Step 2730, the host computer receives the user data carried in the transmission initiated by the base station.

When using the word "comprise" or “comprising” it shall be interpreted as nonlimiting, i.e. meaning "consist at least of".

The embodiments herein are not limited to the preferred embodiments described above. Various alternatives, modifications and equivalents may be used.

Claims

CLAIMS A method performed by a first radio node (110) for handling beam squint in any one out of: a transmission or reception, between the first radio node (110) and a second radio node (120) in a communications network (100), wherein a Grid of Beam, GoB, codebook comprising Beam Indexes, Bls, indicating beam vectors designed for a reference carrier frequency (fO) is defined for said transmission or reception, the method comprising: obtaining (801) for said transmission or reception, measurements of reference signals related to the second radio node (120), which frequency of the reference signals is part of a first carrier frequency (f 1 ) , identifying (802) for the second radio node (120) at the first carrier frequency (f1), a Bl indicating a best beam vector with a best signal quality among the Bls in the GoB codebook, which identifying is based on the obtained reference signal measurements, and the GoB codebook, calculating (803) a beam squint based on the best beam vector, and the GoB codebook, based on the calculated beam squint and the GoB codebook, deciding (805) for a second carrier frequency (f2) to be used for said transmission or reception_± whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint. The method according to claim 1 , wherein the deciding (805) for the second carrier frequency (f2) for said transmission or reception further comprises: deciding for the rest of all respective of the carrier frequencies (f3-fn) to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint. The method according to any of the claims 1-2, wherein any one or more out of (1) and (2) further is based on how close to the beam intersection direction between two beams the direction from which the reference signal of the second radio node (120) appears to be coming from, wherein (1) and (2) comprise:

(1) deciding for the second carrier frequency (f2) for said transmission or reception, whether or not to select a beam vector from the code book that compensates for the calculated beam squint, (2) deciding for the rest of all respective of the carrier frequencies (f3-fn) for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint.

4. The method according to any of the claims 1-3, further comprising: deciding (804) how close to the beam intersection direction between two beams the direction from which the reference signal of the second radio node (120) appears to be coming from based on: measured signal quality in adjacent beam vectors relative to best beam vector at the first carrier frequency (f1).

5. The method according to any of the claims 1-4, wherein whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint is performed to any one or more out of:

- select a beam vector for the second carrier frequency (f2) with higher signal quality than the best beam vector at the first carrier frequency (f1), and

- select a beam vector for the rest of all respective carrier frequencies (f3-fn) with higher signal quality than the best beam vector at the first carrier frequency (f1).

6. The method according to any of the claims 1-5, wherein any one out of: the first radio node (110) is represented by a radio network node and the second radio node (120) is represented by a User Equipment, UE, or the first radio node (110) is represented by a UE and the second radio node (120) is represented by a radio network node.

7. A computer program (1130) comprising instructions, which when executed by a processor (1110), causes the processor (1110) to perform actions according to any of the claims 1-6.

8. A carrier (1140) comprising the computer program (1130) of claim 7, wherein the carrier (1140) is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium. A first radio node (110) configured to handle beam squint in any one out of: a transmission or a reception between the first radio node (110) and a second radio node (120) in a communications network (100), wherein a Grid of Beam, GoB, codebook comprising Beam Indexes, Bls, indicating beam vectors designed for a reference carrier frequency (fO) is adapted to be defined for said transmission or reception, the first radio node (110) further being configured to: obtain for said transmission or reception, measurements of reference signals related to the second radio node (120), which frequency of the reference signals is part of a first carrier frequency (f 1 ) , identify for the second radio node (120) at the first carrier frequency (f1), a Bl indicating a best beam vector with a best signal quality among the Bls in the GoB codebook, which identifying is based on the obtained reference signal measurements, and the GoB codebook, calculate a beam squint based on the best beam vector, and the GoB codebook, based on the calculated beam squint and the GoB codebook, decide for a second carrier frequency (f2) to be used for said transmission or reception_± whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint. The first radio node (110) according to claim 9, wherein the first radio node (110) further is configured to decide for the second carrier frequency (f2) for said transmission or reception by: deciding for the rest of all respective of the carrier frequencies (f3-fn) to be used for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint. The first radio node (110) according to any of the claims 9-10, wherein any one or more out of (1) and (2) further are adapted to be based on how close to the beam intersection direction between two beams the direction from which the reference signal of the second radio node (120) appears to be coming from, wherein (1) and (2) are adapted to comprise:

(1) decide for the second carrier frequency (f2) for said transmission or reception, whether or not to select a beam vector from the code book that compensates for the calculated beam squint, (2) decide for the rest of all respective of the carrier frequencies (f3-fn) for said transmission or reception, whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint.

12. The first radio node (110) according to any of the claims 9-11, further being configured to: decide how close to the beam intersection direction between two beams the direction from which the reference signal of the second radio node (120) appears to be coming from based on: measured signal quality in adjacent beam vectors relative to best beam vector at the first carrier frequency (f1).

13. The first radio node (110) according to any of the claims 9-12, wherein whether or not to select a different beam vector from the GoB codebook that compensates for the calculated beam squint is adapted to be performed to any one or more out of:

14. The first radio node (110) according to any of the claims 9-13, wherein any one out of: the first radio node (110) is represented by a radio network node and the second radio node (120) is represented by a User Equipment, UE, or the first radio node (110) is represented by a UE and the second radio node (120) is represented by a radio network node.