WO2022214189A1

WO2022214189A1 - Network node, user equipment and methods for beam training and alignment

Info

Publication number: WO2022214189A1
Application number: PCT/EP2021/059227
Authority: WO
Inventors: Dario TAGLIAFERRI; Damiano BADINI; Marouane MIZMIZI; Umberto Spagnolini; Christian Mazzucco
Original assignee: Huawei Technologies Co Ltd; Politecnico di Milano
Current assignee: Huawei Technologies Co Ltd; Politecnico di Milano
Priority date: 2021-04-08
Filing date: 2021-04-08
Publication date: 2022-10-13
Anticipated expiration: 2023-10-08

Abstract

A network node that is configured to obtain antenna capability information of one or more user equipment (UEs), when the one or more UEs enter a first area of a radio cell of the network node. The network node communicates one or more spatial directions to be used for transmission to each of the one or more UEs, where the corresponding one or more spatial directions are set at each of the one or more UEs throughout its presence within the first area of radio cell. The network node further obtains information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the first area of radio cell, and cumulates information from multiple UEs until it is possible to determine channel state information for one or more spatial directions supported by UEs antenna capability in each of the different geographical areas.

Description

NETWORK NODE, USER EQUIPMENT AND METHODS FOR BEAM TRAINING AND ALIGNMENT

TECHNICAL FIELD The present disclosure relates generally to the field of wireless communication; and more specifically, to a network node, a user equipment (UE) and methods for use in the network node and the user equipment respectively, for beam training and alignment.

BACKGROUND

In wireless communication systems, such as a fifth-generation (5G) cellular systems and particularly, in vehicle to everything (V2X) communication system, typically a high carrier frequency (e.g., 24.25-52.6 GHz) is used. The use of high carrier frequency results into an order of magnitude increases in free space path loss in such wireless communication systems. The increased path loss can be overcome by use of beam alignment between a base station and wireless users of a cellular network. Generally, the beam alignment between a conventional network node (e.g., the base station) and wireless users of the cellular network is performed by a periodically repeated beam sweeping procedure in order to refresh beam alignment. When wireless users of the cellular network have high mobility, the beam re alignment becomes too frequent that results into an increase in related overhead to an undesirable level. The frequent beam re-alignment is more prominent in cellular based vehicle to everything (cV2X) communication network in which the wireless users are characterized by higher speed and more directive antennas. In such communication network, a validity window of beam alignment become very narrow, resulting in continuous re alignment, which manifests as a significant drop in network efficiency.

Currently, certain attempts have been made to solve the frequent beam re-alignment problem and thereby, reducing the related overhead. In an example, a conventional method employs a beam finding map which associates a wireless user’s position to pre-calculated optical transmit and receive beams to the wireless user, for example, in a V2X communication system. The conventional method of the beam finding map depends on knowledge of the wireless user’s position, which is a sensitive information and is required to be estimated either by a base station in use or shared by the wireless user itself. This may cause privacy issues related to the transmission of the sensitive information regarding the wireless user’s position. Moreover, the way of filling up the beam finding map is not specified. Thus, there exists a technical problem of beam re-alignment when the wireless users have high mobility, for example, in the conventional V2X communication system.

Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with the conventional methods of beam re-alignment when the wireless users have high mobility.

SUMMARY

The present disclosure provides a network node, a user equipment (UE), and methods for use in the network node and the user equipment, respectively, for beam training and alignment. The present disclosure provides a solution to the existing problem of beam re alignment when the wireless users have high mobility, for example, in the conventional V2X communication system. An object of the present disclosure is to provide an improved network node, a user equipment, and methods for use in the network node and the user equipment, respectively, for effective and efficient beam training and alignment.

One or more objects of the present disclosure is achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.

In an aspect, the present disclosure provides a network node, comprising a first control circuitry configured to obtain antenna capability information of one or more user equipment (UEs), when the one or more UEs enter a first area of a radio cell of the network node. The first control circuitry is further configured to communicate a spatial direction to be used for transmission to each of the one or more UEs, wherein a corresponding spatial direction is set at each of the one or more UEs throughout its presence within the first area of the radio cell. According to the antenna capabilities the UEs are not limited to use a single spatial direction but a plurality of spatial directions. The first control circuitry is further configured to obtain information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the first area of the radio cell. The first control circuitry is further configured to cumulate information from multiple UEs until it is possible to determine channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell based on the information obtained from the one or more UEs, wherein the determined channel state information is used to determine one or more spatial directions to be communicated as the spatial directions to be used for transmission for UEs entering the first area of the radio cell of the network node once channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area have been determined.

The disclosed network node is configured to communicate the spatial direction to each of the one or more UEs based on the received antenna capability information from the one or more UEs when the one or more UEs enter the first area of the radio cell of the network node. Therefore, the determination of the spatial direction is independent of position of each of the one or more UEs, avoiding all privacy issues related to transmission of information regarding the position of the one or more UEs. Moreover, the disclosed network node is configured to determine the spatial direction for the one or more UEs when the one or more UEs have high mobility. The determination of channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell based on cumulative information from the multiple UEs results into an improved channel estimation for a next UE that may move over the same geographical area at a later point in time. Thus, the disclosed network node is particularly useful when a wireless channel is subjected to quick variations, for example, in a vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle to everything (V2X) communication system or in mmWave communication system. The disclosed network node takes less time for beam re-alignment in case of the high mobility in comparison to a conventional beam sweeping routine, and ensures high spectral efficiency as compared to conventional communication systems.

In an implementation form, the determination of the channel state information for each of the plurality of different geographical areas comprises determining a signal quality metric for each of the plurality of different geographical areas based on the received information, and determining, for each of the plurality of different geographical areas, a set of beam steering angles ranked based on the determined signal quality metric. The determination of the set of beam steering angles ranked based on the determined signal quality metric results into an improved spectral efficiency.

In a further implementation form, the first control circuitry is further configured to generate a beam-mapping matrix comprising a plurality of signal strength measurements for each of the set of beam steering angles supported by the network node and the one or more UEs and each of the plurality of different geographical areas within the radio cell, such that the signal strength measurements can be used as the signal quality metric.

The beam mapping matrix is useful in order to select an efficient and effective spatial direction for information transmission between the network node and the one or more UEs. In a further implementation form, the first control circuitry is further configured to estimate and store a dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for the plurality of different geographical areas to perform the channel estimation for the next UE.

The estimation and storage of the dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for the plurality of different geographical areas in the end of the training phase results into a more precise channel estimation for the next UE that may move over one or more of the plurality of different geographical areas at a later point in time in the operational phase (online stage or operational deployment stage).

In a further implementation form, the first control circuitry is further configured to estimate each of the plurality of different geographical areas based on a reference system.

The estimation of each of the plurality of different geographical areas based on the reference system reduce the signalling between the network node and the one or more UEs.

In a further implementation form, the first control circuitry is further configured to obtain antenna capability information of one or more user equipment (UEs), when the one or more UEs enter a second area of the radio cell of the network node. The first control circuitry is further configured to communicate one spatial direction to each of the one or more UEs, wherein a corresponding spatial direction is set at each of the one or more UEs throughout its presence within the second area of the radio cell. The first control circuitry is further configured to obtain information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the second area of the radio cell. The first control circuitry is further configured to determine channel state information for each of the plurality of different geographical areas within the second area of the radio cell based on the information obtained from the one or more UEs.

The determination of the channel state information for each of the plurality of different geographical areas based on the information obtained from the one or more UEs, when the one or more UEs enter the second area of the radio cell of the network node, results into a further improvement in spectral efficiency.

In a further implementation form, the obtained information is at least one of: a plurality of pilot symbols, a specific waveform taken from a predefined list, a narrowband signal or a chirp signal.

By virtue of obtaining the information as at least one of the plurality of pilot symbols, the specific waveform taken from the predefined list, the narrowband signal or the chirp signal, signal strength can be measured with more accuracy.

In a further implementation form, the one or more spatial directions to be communicated as a spatial direction to a UE indicate a fixed beam orientation to be used by the UE throughout its presence within the first area of the radio cell.

The use of the spatial direction as the fixed beam orientation by the UE for information transmission towards the network node results into an improved network efficiency.

In another aspect, the present disclosure provides a user equipment (UE) comprising a second control circuitry and an array of antenna, wherein the second control circuitry is configured to control the array of antenna to communicate antenna capability information of the UE to a network node deployed at a fixed location when the UE enters a radio cell of the network node. The second control circuitry is further configured to obtain one or more spatial directions for transmission from the network node to be used throughout the presence of the UE within a first area of the radio cell. The second control circuitry is configured to transmit information towards the one or more spatial directions for transmission obtained from the network node as the UE moves arbitrarily over a plurality of different geographical areas within the first area of the radio cell.

The disclosed UE is configured to obtain the spatial direction for information transmission from the network node based on the antenna capability information communicated to the network node. The disclosed UE does not require to communicate the information regarding its position mandatorily to the network node for obtaining the spatial direction in comparison to a conventional UE which is required to communicate the information regarding its position to the network node for obtaining a conventional spatial direction. Therefore, the disclosed UE manifests an improved security and efficiency in comparison to the conventional UE which is subjected to privacy issues. Moreover, the disclosed UE may have high mobility as well as low mobility. The disclosed UE may be used in a vehicle-to- infrastructure (V2I), vehicle-to-network (V2N), vehicle to everything (V2X) communication system or in mmWave communication system.

In a further implementation form, the spatial direction obtained from the network node indicates a fixed beam orientation to be used by the UE throughout its presence within the first area of the radio cell.

The use of the fixed beam orientation by the UE for information transmission towards the network node results into a further improvement in efficiency of the UE.

In a further implementation form, the second control circuitry is further configured to control the array of antenna to communicate at least one of: a position of the UE or the position as well as an orientation of the UE to the network node.

The communication of at least one of the position of the UE or the position as well as the orientation of the UE to the network node results into a more accurate determination of spatial direction at the network node which is further communicated to the UE.

In a further implementation form, the second control circuitry is further configured to control the array of antenna to obtain a second spatial direction from the network node when the UE enters a second area of the radio cell, the second area is different from the first area. The second control circuitry is further configured to set the second set of one or more spatial directions as an updated active spatial direction at the UE throughout its presence within a second area of the radio cell. The second control circuitry is further configured to transmit the information towards the updated active spatial direction obtained from the network node as the UE moves arbitrarily over a plurality of different geographical areas within the second area of the radio cell.

The information transmission towards the second spatial direction as the updated active spatial direction obtained from the network node as the UE moves arbitrarily over the plurality of different geographical areas within the second area of the radio cell, results into an improved network efficiency.

In a further implementation form, the UE is one of: a vehicle or a mobile device, and wherein the network node is at least one of: a base station, a road-side unit, or a repeater device.

The UE is one of the vehicle or the mobile device that manifests high mobility and the network node is one of: the base station, the road-side unit, or the repeater device which is deployed at a fixed location.

In a yet another aspect, the present disclosure provides a method for use in a network node for beam training and alignment. The method comprises obtaining, by the network node, antenna capability information of one or more user equipment, UEs, when the one or more

UEs enters a first area of a radio cell of the network node. The method further comprises communicating, by the network node, one or more spatial directions to be used for transmission to each of the one or more UEs, wherein the corresponding one or more spatial directions are set at each of the one or more UEs throughout its presence within the first area of the radio cell. The method further comprises obtaining, by the network node, information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the first area of the radio cell. The method further comprises cumulating information from multiple UEs until it is possible to determine channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell based on the information obtained from the one or more UEs, wherein the determined channel state information is used to determine one or more spatial directions to be communicated as the spatial directions to be used for transmission for UEs entering the first area of the radio cell of the network node once channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area have been determined.

The method of the network node achieves all the advantages and effects of the network node of the present disclosure.

In a yet another aspect, the present disclosure provides a method for use in a user equipment (UE), for beam training and alignment. The method comprises communicating, by the UE, antenna capability information of the UE to a network node deployed at a fixed location when the UE enters a first area of a radio cell of the network node. The method further comprises obtaining, by the UE, a spatial direction for transmission from the network node to be used throughout the presence of the UE within a first area of the radio cell. The method further comprises transmitting, by the UE, information towards the one or more spatial directions obtained from the network node as the UE moves arbitrarily over a plurality of different geographical areas within the first area of the radio cell, wherein the information is used for the beam training and alignment.

The method of the UE achieves all the advantages and effects of the UE of the present disclosure.

It is to be appreciated that all the aforementioned implementation forms can be combined. It has to be noted that all devices, elements, circuitry, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:

FIG. 1 is a block diagram that illustrates various exemplary components of a network node, in accordance with an embodiment of the present disclosure;

FIG. 2 is a block diagram that illustrates various exemplary components of a user equipment, in accordance with an embodiment of the present disclosure;

FIG. 3 is a flowchart of a method for use in the network node for beam training and alignment, in accordance with an embodiment of the present disclosure;

FIG. 4 is a flowchart of a method for use in the user equipment for beam training and alignment, in accordance with an embodiment of the present disclosure;

FIG. 5A is a flowchart of beam alignment in a multi-vehicular communication system, in accordance with an embodiment of the present disclosure;

FIG. 5B is a flowchart of beam alignment in a multi-vehicular communication system, in accordance with an embodiment of the present disclosure; FIG. 6 is an illustration that represents a transmitter and a receiver configuration based on uniform rectangular arrays (URA), in accordance with an embodiment of the present disclosure;

FIG. 7A is an illustration of an exemplary scenario that depicts analog beam alignment from a base station to a first vehicle, in accordance with an embodiment of the present disclosure;

FIG. 7B is an illustration of an exemplary scenario that depicts analog beam alignment from the base station to a second vehicle, in accordance with another embodiment of the present disclosure;

FIG. 7C is an illustration of an exemplary scenario that depicts analog beam alignment from the base station to a third vehicle, in accordance with yet another embodiment of the present disclosure;

FIG. 7D is a graphical representation that illustrates a set of analog beams in order to maximize received power, in accordance with an embodiment of the present disclosure;

FIG. 7E is an illustration that represents a power map that depicts received power in decibels (dB) for a number of transmitted beams and received beams, in accordance with an embodiment of the present disclosure;

FIG. 8A is an illustration that represents least square estimation of a compressed channel between the base station and a first vehicle, in accordance with an embodiment of the present disclosure;

FIG. 8B is an illustration that represents least square estimation of a compressed channel between the base station and different vehicles, in accordance with an embodiment of the present disclosure;

FIG. 9 is a sequence diagram that depicts exemplary stages of communication between a base station and one or more user equipment (UEs), in accordance with an embodiment of the present disclosure;

FIG. 10 is an illustration of an exemplary scenario of communication between a base station and a user equipment, in accordance with an embodiment of the present disclosure;

FIG. 11 A is an illustration that depicts various parameters of a wireless channel, in accordance with an embodiment of the present disclosure;

FIG. 1 IB is an illustration of an implementation scenario of a wireless channel, in accordance with an embodiment of the present disclosure; FIG. 12 is an illustration of multiple vehicles crossing a same geographical area, in accordance with an embodiment of the present disclosure;

FIG. 13 is an illustration that depicts hybrid beam forming, in accordance with an embodiment of the present disclosure; and

FIG. 14 is an illustration of graphical representations that depicts variations of spectral efficiency with increase in number of vehicles and with signal-to-noise (SNR) per antenna, in accordance with an embodiment of the present disclosure

In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non- underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.

FIG. 1 is a block diagram that illustrates various exemplary components of a network node, in accordance with an embodiment of the present disclosure. With reference to FIG. 1, there is shown a block diagram 100 of a network node 102 that includes a first control circuitry 104, and a memory 106. The network node 102 may further include an array of antenna 108. The first control circuitry 104 may be communicatively coupled to the memory 106 and the array of antenna 108.

The network node 102 includes suitable logic, circuitry, interfaces, and/or code that is configured to one or more user equipment (UEs) to steer an array of antenna gain towards a particular direction for information transmission. The network node 102 may also be referred to as a coordinator node of a cellular or vehicular network, such as 5G cellular network or vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), or vehicle-to-everything (V2X) communication network. The network node 102, such as a base station, may be deployed at a fixed location, whereas the one or more UEs may be mobile nodes. Examples of the network node 102 include, but are not limited to a base station, a repeater device, an Intemet- of- Things (IoT) controller, a customized hardware for wireless telecommunication, or any other portable or non-portable wireless communication device or system.

The first control circuitry 104 include suitable logic, circuitry, interfaces, and/or code that is configured to obtain antenna capability information of the one or more UEs, when the one or more UEs enter a first area of a radio cell of the network node 102. The first control circuitry 104 may also be configured to execute the instructions stored in the memory 106. In an example, the first control circuitry 104 may be a general-purpose processor. Other examples of the first control circuitry 104 may include, but are not limited to a microprocessor, a microcontroller, a complex instruction set computing (CISC) processor, an application-specific integrated circuit (ASIC) processor, a reduced instruction set (RISC) processor, a very long instruction word (VLIW) processor, a central processing unit (CPU), a state machine, a data processing unit, and other processors or control circuitry. Moreover, the first control circuitry 104 may refer to one or more individual processors, processing devices, a processing unit that is part of a machine, such as the network node 102.

The memory 106 include suitable logic, circuitry, interfaces, and/or code that is configured to store a dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for a plurality of different geographical areas in order to perform a channel estimation. The memory 106 may also be configured to store the instructions executable by the first control circuitry 104. Examples of implementation of the memory 106 may include, but are not limited to, an Electrically Erasable Programmable Read-Only Memory (EEPROM), Random Access Memory (RAM), Read Only Memory (ROM), Hard Disk Drive (HDD), Flash memory, Solid-State Drive (SSD), or CPU cache memory. The memory 106 may also store an operating system or other program products (including one or more operation algorithms) to operate the network node 102.

The array of antenna 108 include suitable logic, circuitry, interfaces, and/or code that is configured to communicate a spatial direction to be used for transmission to each of the one or more UEs. The array of antenna 108 can be steered towards a set of directions (i.e., scanning angles) covering the radio cell of the network node 102. Examples of the array of antenna 108 may include, but are not limited to, an antenna panel, a radio frequency transceiver, a base station antenna array, a network interface, or any other antenna array suitable for use in the network node 102 The array of antenna 108 supports various wireless and cellular communication protocols, such as 4G LTE or mmWave communication, to execute wireless communication.

Generally, the beam alignment between a conventional network node (e.g., the base station) and wireless users of the cellular network is performed by a periodically repeated beam sweeping procedure in order to refresh beam alignment. When wireless users of the cellular network have high mobility, the beam re-alignment becomes too frequent that results into an increase in related overhead to an undesirable level. It is known that whenever a wireless channel is subjected to quick variations (which is expected to happen relatively often in V2X systems), it is not computationally affordable or desirable to run the conventional time- consuming beam sweeping procedure in order to re-align the beams.

Thus, in order to solve the problem of beam re-alignment when the wireless users have high mobility, for example, in the V2X communication, the present disclosure provides a solution that involves beam training and alignment. In the present disclosure, there is a training phase and an operational phase (can also be referred to as an online phase). In the training phase, beam-training operations are carried out using several wireless users, such as one or more user equipment (UEs), in order to re-construct a full electromagnetic picture of signal propagation in the surroundings of the network node 102 Information is collected from several wireless users, such as UEs, related to the radio environment, which can be used to improve not only the analogue controlled beam alignment but also the digitally controlled precoding. This is possible because it has been observed that the wireless channel exhibits evident spatial correlations. Therefore, by leveraging the information obtained in the training phase from multiple UEs (e.g., vehicles) moving in different geographical areas with the radio cell of the network node 102, the channel estimation (and, in turn, digital precoding) for future UEs passing the same geographical areas within the radio cell is improved in the operational phase. At the end of the training procedure, the network node 102 is able to identify pointing directions (for both UE and network node beams) for communication. In other words, the network node 102 is able to determine spatial directions to be communicated as the spatial direction to be used for transmission for various UEs entering a radio cell of the network node 102 in the operational phase (also referred to as online stage). Thus, by replacing the conventional periodic beam sweeping procedure with the beam training and alignment in the present disclosure, comparatively more time can be dedicated to channel estimation in the operational phase resulting in additional gain and spectral efficiency.

In operation, in the training phase, the first control circuitry 104 is configured to obtain antenna capability information of one or more user equipment (UEs), when the one or more UEs enter a first area of a radio cell of the network node 102 The first control circuitry 104 of the network node 102 is configured to obtain the information about antenna capability (i.e., type of antenna equipment or antenna array) of the one or more UEs, when the one or more UEs enter the first area of the radio cell of the network node 102 The radio cell may be defined as a geographical region(s) within which the network node 102 provides a radio coverage to each of the one or more UEs. The first area of the radio cell may be defined as an area in which there is a line of sight (LoS) communication between the network node 102 and the one or more UEs. The UE is described in detail, for example, in FIG. 2.

The first control circuitry 104 is further configured to communicate a spatial direction to be used for transmission to each of the one or more UEs, wherein a corresponding spatial direction is set at each of the one or more UEs throughout its presence within the first area of the radio cell. On the basis of the obtained antenna capability (i.e., type of antenna equipment or antenna array) information of the one or more UEs, the first control circuitry 104 of the network node 102 communicates the spatial direction (i.e., a given direction in space) that is to be used by the network node 102 for information transmission to each of the one or more UEs. The spatial direction may be, for example, a best codebook index (or a set of indices) which the first control circuitry 104 assigns to each of the one or more UEs. Moreover, the corresponding spatial direction set at each of the one or more UEs is kept fixed throughout its presence within the first area of the radio cell of the network node 102. The corresponding spatial direction corresponds to at least one direction that is predefined from a set of directions.

The first control circuitry 104 is further configured to obtain information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the first area of the radio cell. After setting the spatial direction at each of the one or more UEs, the one or more UEs continuously transmit the information to the network node 102 through the set spatial direction. The one or more UEs repeatedly transmit the information to the network node 102 when the one or more UEs move over the plurality of different geographical areas within the first area of the radio cell. Each geographical area of the plurality of different geographical areas may be defined by a geographical position and a radius or by any other reference system, such as an indexed grid.

The first control circuitry 104 is further configured to cumulate information from multiple UEs until it is possible to determine channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell based on the information obtained from the one or more UEs, wherein the determined channel state information is used to determine one or more spatial directions to be communicated as the spatial directions to be used for transmission for UEs entering the first area of the radio cell of the network node 102 once channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area have been determined. The first control circuitry 104 is configured to cumulate the information from multiple UEs moving in different geographical areas with the radio cell of the network node 102. Such information is collected until it becomes possible to determine channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell. Generally, the channel state information may be defined as an information that describes how a signal propagates through a communication channel (i.e., a communication link between the network node 102 and the one or more UEs). The channel state information includes the information that how much the propagated signal is faded or scattered while moving through the channel. The channel state information may also be referred to as channel estimation. The determined channel state information is further used to determine one or more spatial directions to be communicated as the spatial directions to be used for transmission for UEs (e.g. future UEs) entering the first area of the radio cell of the network node 102 once channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area have been determined. Moreover, the determination of channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas improves channel estimation for all the UEs that may enter a same geographical area of the plurality of different geographical areas resulting in improved spectral efficiency.

In accordance with an embodiment, the determination of the channel state information for each of the plurality of different geographical areas comprises determining a signal quality metric for each of the plurality of different geographical areas based on the received information and determining, for each of the plurality of different geographical areas, a set of beam steering angles ranked based on the determined signal quality metric. The first control circuitry 104 of the network node 102 is configured to use to the information received from the one or more UEs in order to determine the signal quality metric (e.g., power measurement) for each of the plurality of different geographical areas. Additionally, the first control circuitry 104 of the network node 102 is further configured to determine the set of beam steering angles which are ranked (or prioritized) based on the determined signal quality metric. Generally, a beam steering angle may be defined as an angle (or signal phase) at which a beam pattern can be randomly altered in real time without making any change in an antenna element or any other circuitry.

In accordance with an embodiment, the first control circuitry 104 is further configured to generate a beam-mapping matrix comprising a plurality of signal strength measurements for each of the set of beam steering angles supported by the network node 102 and the one or more UEs and each of the plurality of different geographical areas within the radio cell, such that the signal strength measurements can be used as the signal quality metric. The first control circuitry 104 of the network node 102 generates the beam-mapping matrix which comprises the plurality of signal strength measurements (e.g., transmission power, received power, etc.) for each of the set of beam steering angles used by the network node 102 and the one or more UEs. Alternatively stated, the first control circuitry 104 of the network node 102 is configured to store information about signal propagation within the first area of the radio cell in terms of the beam-mapping matrix. The plurality of signal strength measurements in the beam-mapping matrix may be used as the signal quality metric for each of the plurality of different geographical areas. In accordance with an embodiment, the first control circuitry 104 is further configured to estimate each of the plurality of different geographical areas based on a reference system. The first control circuitry 104 is further configured to estimate each of the plurality of different geographical areas based on the reference system, for example, a global coordinate system or a UE-local coordinate system, provided that the reference system is known to the network node 102 as well as to the one or more UEs. In case of the global coordinate system (e.g., a global positioning system), the one or more UEs explicitly avoid communicating its heading to the network node 102 which may complete the beam alignment over the one or more UEs pointing beams in different global directions. The network node 102 commands the use of a given direction in space which is kept fixed as the one or more UEs moves in the radio cell of the network node 102 In case of the UE-local coordinate system, the network node 102 may exemplarily command to each of the one or more UEs affixed beam ID in a codebook to be used as the one or more UEs moves in the radio cell. However, in both the reference systems, the use of the fixed beams during the beam alignment is an option to reduce the signalling. Optionally, the beam alignment may also be carried out when the network node 102 commands the one or more UEs to randomly change their transmitted beams (Tx beams) during motion, provided that the one or more UEs report about corresponding transmitted beams used for transmission, to the network node 102 The beam alignment may also be carried out with each of the one or more UEs in an "idle mode" or, more generally, during the period when no data is required to be transmitted.

In accordance with an embodiment, the one or more spatial directions to be communicated as a spatial direction to a UE indicate a fixed beam orientation to be used by the UE throughout its presence within the first area of the radio cell. In an implementation, the first control circuitry 104 of the network node 102 is configured to communicate the one or more spatial directions as the spatial direction to the UE (e.g. a next UE) which is used as the fixed beam orientation by the UE throughout its presence within the first area of the radio cell of the network node 102 The fixed beam orientation may correspond to one or more absolute coordinates. The fixed beam orientation may be indicated by an index in a codebook, for example, a two-dimensional (2D) Fourier basis codebook.

In accordance with an embodiment, the first control circuitry 104 is further configured to obtain antenna capability information of one or more user equipment, UEs, when the one or more UEs enter a second area of the radio cell of the network node. The first control circuitry 104 is further configured to communicate one spatial direction to each of the one or more UEs, wherein a corresponding spatial direction is set at each of the one or more UEs throughout its presence within the second area of the radio cell. The first control circuitry 104 is further configured to obtain information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the second area of the radio cell and determine channel state information for each of the plurality of different geographical areas within the second area of the radio cell based on the information obtained from the one or more UEs. After determining the spatial direction for each of the one or more UEs entering in the first area of the radio cell of the network node 102, the first control circuitry 104 is configured to obtain the antenna capability information (i.e., type of antenna equipment) of the one or more UEs entering the second area of the radio cell of the network node 102. The second area is different from the first area of the radio cell of the network node 102. The second area of the radio cell may be defined as an area in which there is a non-line of sight (NLoS) communication between the network node 102 and the one or more UEs. Alternatively stated, there may be some obstacles like high-rise buildings between the network node 102 and the one or more UEs. Due to the high-rise buildings, there may be reflections etc. and therefore, the second area may have different radio characteristics from the first area, although the first area and the second area both are part of the radio cell of the network node 102. After obtaining the information from the one or more UEs entering the second area of the radio cell, the first control circuitry 104 is further configured to communicate one spatial direction to each of the one or more UEs which is kept fixed throughout its presence within the second area of the radio cell. After setting the spatial direction at each of the one or more UEs, the one or more UEs continuously transmit the information to the network node 102 through the set spatial direction while moving over the plurality of different geographical areas within the second area of the radio cell. The first control circuitry 104 is configured to use the information received from the one or more UEs in order to determine the channel state information for each of the plurality of different geographical areas within the second area of the radio cell.

In accordance with an embodiment, the obtained information is at least one of: a plurality of pilot symbols, a specific waveform taken from a predefined list, a narrowband signal or a chirp signal. The information obtained from the one or more UEs moving over the plurality of different geographical areas within the first area as well as the second area of the radio cell includes one or more of the plurality of pilot symbols, the specific waveform taken from the predefined list, the narrowband signal or the chirp signal. Generally, the plurality of pilot symbols may be defined as tones or any signal that can be used to measure the signal quality metric. Thus, at the end of the training procedure, the network node 102 is able to identify pointing directions (for both UE and network node beams) for communication and determine the channel state information for each of the plurality of different geographical areas within the radio cell. Thus, for each of the plurality of different geographical areas, a full power map (i.e., the beam-mapping matrix) is obtained, as final training result.

In accordance with an embodiment, the first control circuitry 104 is further configured to estimate and store a dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for the plurality of different geographical areas to perform the channel estimation for a next UE. Based on the determined channel state information for each of the plurality of different geographical areas, the first control circuitry 104 of the network node 102 is configured to estimate the dataset of analogue precoders and analogue combiners for analogue controlled beam alignment and digital channel eigenmodes for digitally controlled precoding. Based on the estimated dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for the plurality of different geographical areas, the first control circuitry 104 of the network node 102 is configured to perform the channel estimation (i.e., the improved channel estimation) for the next UE. Moreover, the memory 106 of the network node is configured to store the estimated dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for the plurality of different geographical areas. The dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for the plurality of different geographical areas are not required to be updated unless macroscopic changes in an environment occur.

In the operational phase (e.g., the online stage or communication stage), in an example, when a next UE enters the first area of the radio cell of the network node 102, the UE may also communicate its antenna capability information to the network node 102. However, the next UE is not required to perform frequent alignment or beam re-alignment. In accordance with an embodiment, the first control circuitry 104 is further configured to perform an improved channel estimation for a next UE moving in one or more of the plurality of different geographical areas as a spatial direction is communicated by the network node 102 as the spatial direction to be used for transmission for the next UE entering the first area of the radio cell of the network node 102. In other words, more time can be dedicated to channel estimation in the operational phase resulting in additional gain and spectral efficiency.

Thus, the network node 102 communicates the spatial direction to each of the one or more UEs based on the received information (e.g., a plurality of pilot symbols) from the one or more UEs moving over the plurality of different geographical areas within the first area as well as the second area of the radio cell. Therefore, the determination of the spatial direction is independent on position of each of the one or more UEs, thus, avoids all privacy issues related to transmission of information regarding the position of the one or more UEs. Moreover, the first control circuitry 104 of the network node 102 is configured to determine the spatial direction for the one or more UEs when the one or more UEs have high mobility. This is particularly useful when a wireless channel is subjected to quick variations, such as spatial correlations, for example, in a vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle to everything (V2X) communication system or in mmWave communication system. In such communication system, it is not preferrable to run a beam sweeping routine for beam alignment. Therefore, by leveraging the information that is the plurality of pilot symbols from the one or more UEs and the channel state information for each of the plurality of different geographical areas within the radio cell of the network node 102, it become possible to improve the channel estimation for future vehicles (e.g., the next UE) moving with the radio cell of the network node 102 in the operational phase (or online stage). Thus, the network node 102 may be used in a multi-vehicular communication system such as vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle to everything (V2X) communication system, cellular based V2X communication system or in mmWave communication system.

FIG. 2 is a block diagram that illustrates various exemplary components of a user equipment (UE), in accordance with an embodiment of the present disclosure. FIG. 2 is described in conjunction with elements from FIG. 1. With reference to FIG. 2, there is shown a block diagram 200 of a user equipment (UE) 202 that includes a second control circuitry 204, and an array of antenna 206. The UE 202 may further include a memory 208. The second control circuitry 204 may be communicatively coupled to the array of antenna 206 and the memory

208.

The UE 202 include suitable logic, circuitry, interfaces, and/or code that is configured to communicate antenna capability information to the network node 102 (of FIG. 1). Alternatively stated, the UE 202 may be configured to communicate antenna capability information to the network node 102 in order to steer the array of antenna 206 towards a particular spatial direction from a certain set of N directions. The UE 202 may also be referred to as a mobile node or a user device that is equipped with the array of antenna 206 and is capable to steer (electronically or physically) the array of antenna 206 in the commanded spatial direction. Examples of the UE 202 include, but are not limited to a vehicle, a smart phone, a wireless headphone, an Internet-of- Things (IoT) device or other wireless device with telecommunication capability, a drone, a customized hardware for wireless telecommunication, a transmitter, a receiver, or any other portable communication device.

The second control circuitry 204 includes suitable logic, circuitry, interfaces, and/or code that is configured to control the array of antenna 206 in order to communicate antenna capability information of the UE 202 to the network node 102 deployed at a fixed location when the UE 202 enters a radio cell of the network node 102. In an example, the second control circuitry 204 may be a general-purpose processor. Other examples of the second control circuitry 204 may include, but are not limited to a microprocessor, a microcontroller, a CISC processor, an ASIC processor, a RISC processor, a VLIW processor, a CPU, a state machine, a data processing unit, and other processors or control circuitry.

The array of antenna 206 include suitable logic, circuitry, interfaces, and/or code that is configured to direct a beam of RF signal towards a particular spatial direction from a certain set of N directions in order to communicate antenna capability information of the UE 202 to the network node 102 deployed at the fixed location when the UE 202 enters the radio cell of the network node 102. Examples of the array of antenna 206 may include, but are not limited to, an antenna panel, a radio frequency transceiver, a network interface, a telematics unit, or any other antenna array suitable for use in the UE 202, or other portable communication devices. The array of antenna 206 supports various wireless and cellular communication protocols, such as 4G LTE or mmWave communication, to execute wireless communication.

The memory 208 include suitable logic, circuitry, interfaces, and/or code that is configured to store antenna capability information of the UE 202. The memory 208 may temporally store spatial direction received from the network node 102 for processing purpose. Examples of implementation of the memory 208 may include, but are not limited to, an EEPROM, RAM, ROM, HDD, Flash memory, SSD, or CPU cache memory. The memory 208 may also store an operating system or other program products (including one or more operation algorithms) to operate the UE 202.

In operation, the second control circuitry 204 is configured to control the array of antenna 206 to communicate antenna capability information of the UE 202 to a network node (e.g., the network node 102) deployed at a fixed location when the UE 202 enters the radio cell of the network node 102. The antenna capability information of the UE 202 is communicated to the network node 102 during an initial access performed by the UE 202. For example, the initial access is performed on 5G new radio (NR) frequency range 1 (FR1) (e.g., 4.1 GHz to 7.125 GHz). The UE 202 performs the initial access with an initial setup for mmWave, for example, at 5GNR FR2 (i.e., 24.25 GHz to 52.6 GHz). The antenna capability information includes a type of antenna equipment of the array of antenna 206, a type of antenna element, antenna structure information, a plurality of spatial directions supported by the array of antenna 206 of the UE 202, and the like.

The second control circuitry 204 is further configured to control the array of antenna 206 to obtain one or more spatial directions for transmission from the network node 102 to be used throughout the presence of the UE 202 within a first area of the radio cell. The second control circuitry 204 of the UE 202 is configured to obtain the spatial direction (e.g., a set of indices or a beam) from the network node 102. The spatial direction is used by the network node 102 as well as the UE 202 in order to transmit the information among each other as the UE 202 moves within the first area of the radio cell of the network node 102. There may be a line of sight (LoS) communication between the network node 102 and the UE 202 in the first area of the radio cell. The second control circuitry 204 is further configured to control the array of antenna 206 to transmit information towards the one or more spatial directions for transmission obtained from the network node 102 as the UE 202 moves arbitrarily over a plurality of different geographical areas within the first area of the radio cell. As the UE 202 moves arbitrarily over the plurality of different geographical areas within the first area of the radio cell, the second control circuitry 204 of the UE 202 continuously transmit the information (e.g., a plurality of pilot symbols) towards the network node 102 using the spatial direction obtained from the network node 102.

In accordance with an embodiment, the second control circuitry 204 is further configured to perform an initial access operation for a radio frequency communication with the network node 102, wherein the antenna capability information, which comprises a plurality of spatial directions supported by the array of antenna 206 of the UE 202, is communicated to the network node 102 during the initial access operation. The second control circuitry 204 of the UE 202 is configured to perform the initial access operation for the radio frequency communication with the network node 102. The radio frequency communication is carried out at frequency range 1 (FR1) of the 5G NR (i.e. 4.1 GHz to 7.125 GHz). Moreover, the antenna capability information of the UE 202 is communicated to the network node 102 during the initial access. The antenna capability information also comprises the plurality of spatial directions supported by the array of antenna 206 of the UE 202.

In accordance with an embodiment, the initial access operation is performed to establish a mmWave communication with the network node 102. The second control circuitry 204 of the UE 202 is configured to establish the mmWave communication with the network node 102. The mmWave communication is established at a frequency range of 5G R FR2.

In accordance with an embodiment, the spatial direction obtained from the network node 102 indicates a fixed beam orientation to be used by the UE 202 throughout its presence within the first area of the radio cell. In another implementation, the spatial direction obtained from the network node 102 may be the fixed beam orientation which the array of antenna 206 of the UE 202 is configured to use throughout the presence of the UE 202 within the first area of the radio cell of the network node 102. The fixed beam orientation may correspond to one or more absolute coordinates. In accordance with an embodiment, the second control circuitry 204 is further configured to control the array of antenna 206 to communicate at least one of: a position of the UE 202 or the position as well as an orientation of the UE 202 to the network node 102. The array of antenna 206 is configured to communicate at least the position of UE 202 or the position as well as the orientation of the UE 202 to the network node 102 during the initial access operation.

In accordance with an embodiment, the second control circuitry 204 is further configured to control the array of antenna 206 to obtain a second set of one or more spatial directions from the network node 102 when the UE 202 enters a second area of the radio cell, the second area being different from the first area. The second control circuitry 204 is further configured to control the array of antenna 206 to set the second set of one or more spatial directions as an updated active spatial direction at the UE 202 throughout its presence within the second area of the radio cell and transmit the information towards the updated active spatial direction obtained from the network node 102 as the UE 202 moves arbitrarily over a plurality of different geographical areas within the second area of the radio cell. When the UE 202 enters the second area of the radio cell of the network node 102, the array of antenna 206 is configured to obtain the second spatial direction from the network node 102. The second area is different from the first area. For example, there may be a non-line of sight (NLoS) communication between the network node 102 and the UE 202 in the second area of the radio cell. The second spatial direction is set as the updated active spatial direction. Thereafter, the array of antenna 206 is configured to transmit the information (e.g., a training preamble) to the network node 102 through the updated active spatial direction as the UE 202 moves arbitrarily over the plurality of different geographical areas within the second area of the radio cell.

In accordance with an embodiment, the transmitted information is at least one of: a plurality of pilot symbols, a specific waveform taken from a predefined list, a narrowband signal or a chirp signal. The array of antenna 206 is configured to transmit the information about the UE 202 in at least one of the plurality of pilot symbols, the specific waveform taken from the predefined list, the narrowband signal or the chirp signal. In accordance with an embodiment, the transmitted information is used by the network node 102 to determine a channel state information for each of the plurality of different geographical regions, and wherein the channel state information for each of the plurality of different geographical regions is used by the network node 102 for a beam alignment for each of the plurality of different geographical regions for a next UE when the next UE moves in the plurality of different geographical regions within the radio cell of the network node 102

In accordance with an embodiment, the UE 202 is one of: a vehicle or a mobile device, and wherein the network node 102 is at least one of: a base station, a road-side unit, or a repeater device. In an implementation, the UE 202 may be the vehicle or the mobile device having high mobility and the network node 102 may be one of the base station, the road-side unit or the repeater device which is deployed at the fixed location.

Thus, the UE 202 is configured to obtain the spatial direction for information transmission from the network node 102 based on the antenna capability information communicated to the network node 102. Beneficially, the UE 202 does not require to communicate the information regarding its position mandatorily to the network node 102 for obtaining the spatial direction in comparison to a conventional UE which is required to communicate the information regarding its position to the network node 102 for obtaining a conventional spatial direction. Therefore, the UE 202 manifests an improved security and efficiency in comparison to the conventional UE which is subjected to privacy issues. Moreover, the UE 202 may have high mobility as well as low mobility. Thus, the UE 202 may be used in a vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle to everything (V2X) communication system or in mmWave communication system.

FIG. 3 is a flowchart of a method for use in a network node for beam training and alignment, in accordance with an embodiment of the present disclosure. FIG. 3 is described in conjunction with elements from FIGs. 1 and 2. With reference to FIG. 3, there is shown a method 300 for use in the network node for beam training and alignment. The method 300 includes steps 302 to 308. The method 300 is executed by the network node 102 (of FIG. 1).

At step 302, the method 300 comprises obtaining, by the network node 102, antenna capability information of one or more user equipment (UEs), when the one or more UEs enter a first area of a radio cell of the network node 102. The first control circuitry 104 of the network node 102 is configured to obtain the antenna capability information of the one or more UEs (e.g., the UE 202), when the one or more UEs enter the first area of the radio cell of the network node 102.

At step 304, the method 300 further comprises communicating, by the network node 102, one or more spatial directions to be used for transmission to each of the one or more UEs, wherein the corresponding spatial directions are set at each of the one or more UEs throughout its presence within the first area of the radio cell. Based on the obtained antenna capability information of the one or more UEs (e.g., the UE 202), the first control circuitry 104 of the network node 102 is configured to communicate the spatial direction to be used for transmission to each of the one or more UEs. Also, the corresponding spatial direction is set at each of the one or more UEs (e.g. the UE 202) throughout its presence within the first area of the radio cell of the network node 102.

At step 306, the method 300 further comprises obtaining, by the network node 102, information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the first area of the radio cell. The first control circuitry 104 of the network node 102 is configured to obtain the information from each of the one or more UEs (e.g. the UE 202) as the one or more UEs moves over the plurality of different geographical areas within the first area of the radio cell.

In accordance with an embodiment, the obtained information is at least one of: a plurality of pilot symbols, a specific waveform taken from a predefined list, a narrowband signal or a chirp signal.

At step 308, the method 300 further comprises cumulating information from multiple UEs until it is possible to determine channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell based on the information obtained from the one or more

UEs, wherein the determined channel state information is used to determine one or more spatial directions to be communicated as the spatial directions to be used for transmission for UEs entering the first area of the radio cell of the network node 102 once channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area have been determined. The first control circuitry 104 of the network node 102 is configured to cumulate information from multiple UEs until it become possible todetermine the channel state information (e.g. received power) for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell based on the information (e.g. a plurality of pilot symbols) obtained from the one or more UEs. The determined channel state information is used to determine one or more spatial directions to be communicated as the spatial directions to be used for transmission for UEs entering the first area of the radio cell of the network node 102 once channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area have been determined. In accordance with an embodiment, the determination of the channel state information for each of the plurality of different geographical areas comprises: determining a signal quality metric for each of the plurality of different geographical areas based on the received information; and determining, for each of the plurality of different geographical areas, a set of beam steering angles ranked based on the determined signal quality metric.

In accordance with an embodiment, the method 300 further comprises generating, by the network node 102, a beam-mapping matrix comprising a plurality of signal strength measurements for each of the set of beam steering angles supported by the network node and the one or more UEs and each of the plurality of different geographical areas within the radio cell, such that the signal strength measurements can be used as the signal quality metric.

In accordance with an embodiment, the method 300 further comprises estimating and storing, by the network node 102, a dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for the plurality of different geographical areas to perform the channel estimation for the next UE. The method 300 further comprises estimating, by the network node 102, each of the plurality of different geographical areas based on a reference system.

In accordance with an embodiment, the one or more spatial directions to be communicated as a spatial direction to a UE (e.g. the UE 202 of FIG. 2) indicate a fixed beam orientation to be used by the UE throughout its presence within the first area of the radio cell. In accordance with an embodiment, the method 300 further comprises obtaining, by the network node 102, antenna capability information of one or more user equipment, UEs, when the one or more UEs enter a second area of the radio cell of the network node. The method 300 further comprises communicating, by the network node 102, one or more spatial directions to each of the one or more UEs, wherein the corresponding one or more spatial directions are set at each of the one or more UEs throughout its presence within the second area of the radio cell. The method 300 further comprises obtaining, by the network node 102, information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the second area of the radio cell. The method 300 further comprises determining, by the network node 102, channel state information for each of the plurality of different geographical areas within the second area of the radio cell based on the information obtained from the one or more UEs.

The steps 302 to 308 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.

FIG. 4 is a flowchart of a method for use in a user equipment for beam training and alignment, in accordance with an embodiment of the present disclosure. FIG. 4 is described in conjunction with elements from FIGs. 1, 2, and 3. With reference to FIG. 4, there is shown a method 400 for use in the user equipment (UE) for beam training and alignment. The method 400 includes steps 402 to 406. The method 400 is executed by the UE 202 (of FIG. 2)·

At step 402, the method 400 comprises communicating, by the UE 202, antenna capability information of the UE 202 to a network node (i.e. the network node 102) deployed at a fixed location when the UE 202 enters a first area of a radio cell of the network node 102. The second control circuitry 204 of the UE 202 is configured to control the array of antenna 206 to communicate antenna capability information of the UE 202 to the network node 102 deployed at the fixed location when the UE 202 enters the first area of the radio cell of the network node 102.

At step 404, the method 400 further comprises obtaining, by the UE 202, one or more spatial directions for transmission from the network node 102 to be used throughout the presence of the UE 202 within the first area of the radio cell. The second control circuitry 204 of the UE 202 is configured to control the array of antenna 206 to obtain the one or more spatial directions for transmission from the network node 102 throughout the presence of the UE 202 within the first area of the radio cell.

In accordance with an embodiment, the spatial direction obtained from the network node 102 indicates a fixed beam orientation to be used by the UE 202 throughout its presence within the first area of the radio cell.

At step 406, the method 400 further comprises transmitting, by the UE 202, information towards the one or more spatial directions obtained from the network node 102 as the UE 202 moves arbitrarily over a plurality of different geographical areas within the first area of the radio cell, wherein the information is used for the beam training and alignment. The second control circuitry 204 of the UE 202 is configured to control the array of antenna 206 to transmit the information using the spatial direction to the network node 102 as the UE 202 moves arbitrarily over the plurality of different geographical areas within the first area of the radio cell. The transmitted information is further used for beam training and alignment depending on an application scenario.

In accordance with an embodiment, the method 400 further comprises performing, by the UE 202, an initial access operation for a radio frequency communication with the network node 102, wherein the antenna capability information, which comprises a plurality of spatial directions supported by the array of antenna 206 of the UE 202, is communicated to the network node 102 during the initial access operation. The initial access operation is performed to establish a mmWave communication with the network node 102.

In accordance with an embodiment, the method 400 further comprises controlling, by the UE 202, the array of antenna 206 to communicate at least one of: a position of the UE or the position as well as an orientation of the UE 202 to the network node 102.

In accordance with an embodiment, the method 400 further comprises controlling, by the UE 202, the array of antenna to obtain a second set of one or more spatial directions from the network node 102 when the UE 202 enters a second area of the radio cell, the second area being different from the first area. The method 400 further comprises setting, by the UE 202, the second spatial direction as an updated active spatial direction at the UE 202 throughout its presence within a second area of the radio cell, and transmitting the information towards the updated active spatial direction obtained from the network node 102 as the UE 202 moves arbitrarily over a plurality of different geographical areas within the second area of the radio cell. The transmitted information is at least one of: a plurality of pilot symbols, a specific waveform taken from a predefined list, a narrowband signal or a chirp signal.

In accordance with an embodiment, the transmitted information is used by the network node 102 to determine a channel state information for each of the plurality of different geographical regions, and wherein the channel state information for each of the plurality of different geographical regions is used by the network node 102 for a beam alignment for each of the plurality of different geographical regions for a next UE when the next UE moves in the plurality of different geographical regions within the radio cell of the network node 102

The steps 402 to 406 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.

FIG. 5 A is a flowchart of beam alignment in a multi-vehicular communication system, in accordance with an embodiment of the present disclosure. FIG. 5A is described in conjunction with elements from FIGs. 1, 2, 3, and 4. With reference to FIG. 5A, there is shown a flowchart 500A of beam alignment in a multi-vehicular communication system.

The flowchart 500A inlcudes a first stage 502 (also represented as stage 1), a second stage 504 (also represented as stage 2) and a third stage 506 (also represented as an online stage). The first stage 502 (i.e. stage 1) includes operations 502A and 502B. The second stage 504 (i.e. stage 2) includes operations 504A and 504B. The third stage 506 (i.e. online stage) includes operaions 506A, 506B and 506C.

In the flowchart 500A, the first stage 502 (i.e. stage 1) and the second stage 504 (i.e. stage 2) together act as a two-stage training process for channel estimation that includes one or more UEs. In case of the one or more UEs, it is assumed that the one or more UEs are allocated on mimimally interfering angular, or frequency, or time radio resources. The two- stage training process may be applied to low mobility as well as high mobility scenarios such as vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle to everything (V2X) communication system, cellular based V2X (cV2X) communication system or in mmWave communication system.

In the first stage 502 (i.e. stage 1), an analog precoder ( F_rf ) and analog combiner (W_RF) is determined at the network node 102 and at the UE 202 using a multi-vehicular codebook based beam alignment procedure, such as the method 300 and the method 400, respectively. In the second stage 504 (i.e. stage 2) least square (LS) estimation of a compressed channel is performed in order to compute eigen modes from a training signal received from the first stage 502 (i.e. sateg 1). The computed eigen modes are used to obtain low rank (LR) estimated channel. In the third stage 506 (i.e. online stage), the network node 102 and the UE 202 may be configured to use the analog precoder ( F_rf ) and the analog combiner (W_RF) determined in the first stage 502 (i.e. stage 1) in order to transmit training sequences for digital low rank (LR) channel estimation. Based on the compressed channel (i.e. after analog beamforming), the network node 102 may be configured to derive a digital predcoder ( F_BB ) and a digital combiner (W_BB). The third stage 506 (i.e. online stage) may also be referred to as online phase, or communiation phase or communication stage. At the end of two-stage training procedure, the network node 102 may be configured to store a dataset of the analog precoder ( F_rf ) and analog combiner (W_RF) and digital channel eigenmodes which are not required to be updated unless macroscopic changes in an environment occur. In this case, during the third stage 506 (i.e. online stage), beneficially, periodic or frequent beam re alignment is not required, i.e., can be avoided.

At operation 502A of the first stage 502 (i.e. stage 1), the network node 102 may be configured to command the UE 202 for analog beam alignment when the UE 202 enters the radio cell of the network node 102.

At operation 502B, the network node 102 may be configured to command the UE 202 a spatial direction (or a certain analog beam or analog precoder, F_rf ) when the UE 202 enters the radio cell of the network node 102. As the UE 202 moves over a plurality of different geographical areas within the readio cell of the network node 102, the UE 202 continuously transmit information (i.e. the plurality of pilot symbols) to the network node 102 using the commanded spatial direction (i.e. the analog beam, F_rf ). As the UE 202 moves, the network node 102 may be configured to obtain the information and scan all analog beams (i.e. the analog combiner, W_RF). In case of a match between the network node 102 and the UE 202, spatial directions (or analog beams), the network node 102 may be configured to store the analog precoder ( F_rf ) and the analog combiner (W_RF ) for the plurality of different geographical areas to perform the channel estimation for a next UE.

At operation 504A of the second stage 504 (i.e. stage 2), an approximate least square (LS) estimation ( H_LS ) of the compressed channel is performed using the the analog precoder ( F_rf ) and the analog combiner (W_RF) for the plurality of different geographical areas within the radio cell of the network node 102.

At operation 504B of the second stage 504 (i.e. stage 2), singular vectors ( or eigen modes U_ST ) of the LS estimator (H_LS) are computed.

At operation 506A of the third stage 506 (i.e. stage 3), an approximate least square (LS) estimation ( H_LS ) of the compressed channel is performed using the the analog precoder ( F_rf ) and the analog combiner (W_RF) for the plurality of different geographical areas within the radio cell of the network node 102.

At operation 506B of the third stage 506 (i.e. stage 3), the LS estimator ( H_LS ) of the compressed channel is used to obtain a LR estimation ( H_LR ) of the compressed channel. Thereafter, the LR estimator ( H_LR ) is used to obtain the digital predcoder (F_BB) and the digital combiner (W_BB) at operation 506C.

FIG. 5B illustrates use of the digital precoder and the digital combiner in the multi-vehicular communication system, in accordance with an embodiment of the present disclosure. FIG. 5B is described in conjunction with elements from FIGs. 1 to 4 and 5A. With reference to FIG. 5B, there is shown a flowchart 500B for use of the digital precoder and the digital combiner in the multi-vehicular communication system (e.g., a Hybrid mmWave MIMO systems).

In the flowchart 500A of FIG. 5A, the digital predcoder ( F_BB ) and the digital combiner (W_BB) are obtained at operation 506C of the third stage 506 (i.e. online stage). Thereafter, in the flowchart 500B of this FIG. 5B, at operation 508, the digital predcoder ( F_BB ) is further used to compute singular value decomposition (SVD) for the multi-vehicular communication system. At operation 510, the digital combiner (W_BB) is obtained using an unconstrained minimum mean square error (MMSE) of the LR estimated compressed channel.

FIG. 6 is an illustration that represents a transmitter and a receiver configuration based on uniform rectangular arrays (URA), in accordance with an embodiment of the present disclosure. FIG. 6 is described in conjunction with elements from FIGs. 1, 2, 3, 4, and 5. With reference to FIG. 6, there is shown an exemplary scenario 600 that includes a transmitter and a receiver configuration based on uniform rectangular arrays (URA).

In the exemplary scenario 600, the UE 202 acts as the transmitter (Tx) and the network node 102 acts as the receiver (Rx). The array of antenna 206 of the UE 202 corresponds to the uniform rectangular arrays (URA) and its configuration is represented in a dotted box 602. Similarly, the array of antenna 108 of the network node 102 corresponds to the uniform rectangular arrays (URA) and its configuration is represented in a dotted box 604. The array of antenna 206 of the UE 202 is configured to transmit the information by use of analog beams represented by a dotted box 606. Similarly, the array of antenna 108 of the network node 102 is configured to transmit the information by use of analog beams represented by a dotted box 608. These analog beams are selected from a two-dimensional (2D) fourier basis which is used as a codebook.

FIG. 7A is an illustration of an exemplary scenario that depicts analog beam alignment from a base station to a first vehicle, in accordance with an embodiment of the present disclosure. FIG. 7A is described in conjunction with elements from FIGs. 1 to 6. With reference to FIG. 7 A, there is shown an exemplary scenario 700A that includes a base station 702 (also represented as BS) and a first vehicle 704 (also represented as A). There is further shown a first geographical area 706 (also represented as vi) and a second geographical area 708 (also represented as V2). The first geographical area 706 and the second geographical area 708 lies within a radio cell of the base station 702.

In the exemplary scenario 700A, the base station 702 corresponds to the network node 102 (of FIG. 1) and the first vehicle 704 corresponds to the UE 202 (of FIG. 2). The first geographical area 706 and the second geographical area 708 corresponds to the plurality of different geographical areas within the radio cell of the base station 702.

In the exemplary scenario 700A, when the first vehicle 704 enters the first geographical area 706 within the radio cell of the base station 702, the first vehicle 704 communicates its antenna capability information to the base station 702 through a pointing direction 710. After receiving the antenna capability information of the first vehicle 704, the base station 702 is configured to assign a first fixed beam pointing direction 712 (also represented as beam #1) to the first vehicle 704. Thereafter, the first vehicle 704 may be configured to transmit the information using the first fixed beam pointing direction 712 (i.e. beam #1) as long as the first vehicle 704 moves in the first geographical area 706 (i.e. vi). Moreover, as the first vehicle 704 moves from the first geographical area 706 (i.e. vi) to the second geographical area 708 (i.e. V2), the first vehicle 704 may be configured to keep transmitting the information using the first fixed beam pointing direction 712 (i.e. beam #1). Such information obtained by the base station 702 from a plurality of UEs, such as the first vehicle 704, is used in the training phase for beam training and alignment, such as in the first stage 502 (i.e. stage 1) of training. The communication between the base station 702 and the first vehicle 704 may occur directly or via a road side unit (RSU) 713.

FIG. 7B is an illustration of an exemplary scenario that depicts analog beam alignment from the base station to a second vehicle, in accordance with another embodiment of the present disclosure. FIG. 7B is described in conjunction with elements from FIGs. 1 to 6 and 7A. With reference to FIG. 7B, there is shown an exemplary scenario 700B that includes the base station 702 and a second vehicle 714 (also represented as B). The second vehicle 714 corresponds to the UE 202 (of FIG. 2).

In the exemplary scenario 700B, when the second vehicle 714 enters the first geographical area 706 (also represented as vi) within the radio cell of the base station 702, the second vehicle 714 may also communicate its antenna capability information to the base station 702 through a pointing direction 716. After receiving the antenna capability information of the second vehicle 714, the base station 702 may be configured to assign a second fixed beam pointing direction 718 (also represented as beam #2) to the second vehicle 714. Thereafter, the second vehicle 714 transmits the information using the second fixed beam pointing direction 718 (i.e. beam #2) as long as the second vehicle 714 moves in the first geographical area 706 (i.e. vi). Moreover, as the second vehicle 714 moves from the first geographical area 706 (i.e. vi) to the second geographical area 708 (i.e. V2), the second vehicle 714 may be configured to keep transmitting the information using the second fixed beam pointing direction 718 (i.e. beam #2). Such information obtained by the base station 702 from a plurality of UEs, such as the first vehicle 704 (FIG. 7A) and the second vehicle 714, is used in the training phase for beam training and alignment, such as in the first stage 502 (i.e. stage 1) of training. The communication between the base station 702 and the first vehicle 704 may occur directly or via the RSU 713. Based on such information obtained from the plurality of UEs like the first vehicle 704 and the second vehicle 714, channel state information is determined for each of the plurality of different geographical areas, such as the first geographical area 706 and the second geographical area 708, within the first area of the radio cell in the training phase. The determined channel state information is used to determine the spatial direction to be communicated as the spatial direction to be used for transmission for next UEs later, such as another vehicle, entering the radio cell of the base station 702.

FIG. 7C is an illustration of an exemplary scenario that depicts analog beam alignment from the base station to a third vehicle, in accordance with yet another embodiment of the present disclosure. FIG. 7C is described in conjunction with elements from FIGs. 1 to 6, 7A and 7B. With reference to FIG. 7C, there is shown an exemplary scenario 700C that includes the base station 702 and a third vehicle 720 (also represented as C).

Similar to the FIGs. 7A and 7B, in the exemplary scenario 700C, when third vehicle 720 enters the first geographical area 706 (i.e. vi) located within the radio cell of the base station 702, the third vehicle 720 communicates its antenna capability information to the base station 702 through a pointing direction 722. After receiving the antenna capability information of the third vehicle 720, the base station 702 assigns a third fixed beam pointing direction 724 (also represented as beam #3) to the third vehicle 720. Thereafter, the third vehicle 720 transmits information using the third fixed beam pointing direction 724 (i.e. beam #3) as long as the third vehicle 720 moves in the first geographical area 706 (i.e. vi) and the second geographical area 708 (i.e. V2). In this way, now referring to FIGs. 7A, 7B, and 7C, each of the exemplary scenarios 700A, 700B, and 700C of FIG. 7A, 7B and 7C respectively corresponds to a same vehicular network, in which each of the first vehicle 704, the second vehicle 714 and the third vehicle 720 crosses the first geographical area 706 (i.e. vi) and the second geographical area 708 (i.e. V2). Moreover, each of the first vehicle 704, the second vehicle 714 and the third vehicle 720 may be configured to communicate the information to the base station 702 using the first fixed beam pointing direction 712 (i.e. beam #1), the second fixed beam pointing direction 718 (i.e. beam #2) and the third fixed beam pointing direction 724 (i.e. beam #3), respectively, when each vehicle (such as the vehicles 704, 714, 720) moves from the first geographical area 706 (i.e. vi) to the second geographical area 708 (i.e. V2). Each of the first fixed beam pointing direction 712 (i.e. beam #1), the second fixed beam pointing direction 718 (i.e. beam #2) and the third fixed beam pointing direction 724 (i.e. beam #3) is selected from a two-dimensional (2D) discrete fourier transform (DFT), described in detail, for example, in FIG. 7D.

Thereafter, the base station 702 may be configured to store power measurements acquired for each geographical area Vi (i.e. the first geographical area 706 (i.e. vi) and the second geographical area 708 (i.e. V2)) crossed by each of the first vehicle 704, the second vehicle 714 and the third vehicle 720. The power measurements associated with each of the first vehicle 704, the second vehicle 714 and the third vehicle 720 crossing the first geographical area 706 (i.e. vi) is represented as power measurement #11, vl, power measurement #21, vl and power measurement #31, vl, respectively. Similarly, the power measurements associated with each of the first vehicle 704, the second vehicle 714 and the third vehicle 720 crossing the second geographical area 708 (i.e. V2) is represented as power measurement #11, v2, power measurement #21, v2 and power measurement #31, v2, respectively. Thus, the base station 702 is configured to store power measurements for each vehicle crossing the same geographical area. In this way, the base station 702 fills a power measurement table with all poining directions (e.g. #n) and all geographical areas Vi. Such power measurements is used in the training phase for beam training and alignment, such as in the first stage 502 (i.e. stage 1) of training. The power measurement table is described in detail, for example, in FIG. 7E. The power measurement table is also referred to as the beam-mapping matrix. These power measurements are further used at a later stage for selection of an improved spatial direction (or analog beam) for a next vehicle crossing the same geographical area. The power measurements and the selection of the improved spatial direction (or analog beam) for the next vehicle crossing the same geographical area is represented in a dotted section 726.

FIG. 7D is a graphical representation that illustrates a set of analog beams in order to maximize received power, in accordance with an embodiment of the present disclosure. FIG. 7D is described in conjunction with elements from FIGs. 1 to 6, 7A, 7B, and 7C. With reference to FIG. 7D, there is shown a graphical representation 700D that represents a set of analog beams in order to maximize received power. The graphical representation 700D includes an X-axis 728A that represents transmitted (Tx) beams in a range of 2 to 16 and a Y-axis 728B that represents received (Rx) beams in a range of 10 to 60.

With reference to the graphical representation 700D, a first dotted box 730 represents a set of analog beams (or spatial directions) which are used as transmitted (Tx) beams. The set of analog beams may also be referred to as a set of optimal (i.e. improved) analog beams which are used in order to maximize received power. The set of analog beams (or spatial directions) are derived from a two-dimensional (2D) discrete fourier transform (DFT) according to equation 1.

- F(

FRF — P 2-D -DFT (1) Similarly, a second dotted box 732 is used to represent a combination of analog beams which are used as received (Rx) beams. The combination of analog beams may be performed by use of an analog combiner, according to equation 2.

FIG. 7E is an illustration that represents a power map that depicts received power in decibels (dB) for a number of transmitted beams and received beams, in accordance with an embodiment of the present disclosure. FIG. 7E is described in conjunction with elements from FIGs. 1 to 6, 7A, 7B, 7C, and 7D. With reference to FIG. 7E, there is shown a power map 700E (i.e. the beam-mapping matrix) that represents power measurements (in dB) in all pointing directions (e.g. N pointing directions) and all geographical areas crossed by each vehicle.

The power map 700E can be also referred to as the beam-mapping matrix, and includes a transmitted (Tx) beam and a received (Rx) beam for each geographical area and for each fixed beam pointing direction (or spatial direction) assigned by the base station 702 to each of the first vehicle 704, the second vehicle 714 and the third vehicle 720. The power map 700E includes an X-axis 734 that represents index of transmitted (Tx) analog beams and a Y-axis 736 that represents index of received (Rx) analog beams. There is further shown a first dotted box 738 with pointing arrows that represents selected beams with power measurements of -34.3dB, -40.3dB and -44.8dB at receiver (Rx) and a second dotted box 740 with pointing arrows that represents selected beams with power measurements of - 35.9dB, -33.1dB and -25.8dB at transmitter (Tx).

FIG. 8A is an illustration that represents least square estimation of a compressed channel between the base station and the first vehicle, in accordance with an embodiment of the present disclosure. FIG. 8A is described in conjunction with elements from FIGs. 1 to 6, 7A, 7B, 7C, 7D, and 7E. With reference to FIG. 8A, there is shown a vehicular network 800A that includes least square estimation of a compressed channel between the base station 702 and the first vehicle 704 (of FIG. 7A). There is further shown an approximated first geographical area 802 (also represented as v_±) and an approximated second geographical area 804 (also represented as v₂).

In accordance with an embodiment, after performing least square (LS) estimation of the compressed channel between the base station 702 and the first vehicle 704, it is approximated that the first fixed beam pointing direction 712 (i.e. beam #1) that was originally assigned to the first vehicle 704 may be changed to another beam 806 (also represented as beam #4) in the approximated first geographical area 802 (i.e.

). In the approximated second geographical area 804 (i.e. v₂), the beams assigned to the first vehicle 704 may be changed to one of the second fixed beam pointing direction 718 (i.e. beam #2) and another beam 808 (also represented as beam #5).

FIG. 8B is an illustration that represents least square estimation of a compressed channel between the base station and each of different vehicles, in accordance with an embodiment of the present disclosure. FIG. 8B is described in conjunction with elements from FIGs. 1 to 6, 7A, 7B, 7C, 7D, 7E, and 8A. With reference to FIG. 8B, there is shown a vehicular network 800B that includes least square estimation of a compressed channel between the base station 702 and each of the first vehicle 704 (of FIG. 7A), the second vehicle 714 (of FIG. 7B) and the third vehicle 720 (of FIG. 7C).

In the vehicular network 800B, the least square (LS) estimation of the compressed channel between the base station 702 and each of the plurality of vehicles, such as the first vehicle 704, the second vehicle 714 and the third vehicle 720 is performed at a stage 810. After performing the LS estimation of the compressed channel, singular vectors (i.e. U_ST ) are computed, which are further used to compute an improved spatial direction for a next vehicle crossing the same geographical area.

FIG. 9 is a sequence diagram that depicts exemplary stages of communication between a base station and one or more user equipments (UEs), in accordance with an embodiment of the present disclosure. FIG. 9 is described in conjunction with elements from FIGs. 1 to 6, 7 A, 7B, 7C, 7D, 7E, 8 A, and 8B. With reference to FIG. 9, there is shown a flowchart 900 that depicts exemplary stages of communication between a base station and one or more user equipments (UEs). There is further shown N number of user equipments, such as a first UE 902A (also represented as UEi) upto a Nth UE 902N (also represented as UE_n) and a base station 904 (also represented as BS). Each of the first UE 902A upto the Nth UE 902N corresponds to the UE 202 (of FIG. 2) and the base station 904 corresponds to the network node 102 (of FIG. 1). There is further shown a first stage 906, a second stage 908 and a third stage 910.

In the first stage 906, each of the first UE 902A upto the Nth UE 902N may be configured to communicate antenna capability information to the base station 904. Firstly, an initial access is performed between the base station 904 and each of the first UE 902A upto the Nth UE 902N. The initial accessmay also be referred to as handshake operation between the base station 904 and each of the first UE 902A upto the Nth UE 902N.

After the handshake between the base station 904 and each of the first UE 902A upto the

Nth UE 902N, the base station 904 may be configured to assign a beam to each of the first

UE 902A upto the Nth UE 902N during the second stage 908. For example, in the second stage 908, beam 1 is assigned to the first UE 902A and beam n is assigned to the Nth UE 902N. The second stage 908 may also be referred to as training set up and is performed at 5G RFR1 (i.e. 4.1 GHz to 7.125 GHz).

In the third stage 910, after beam assignment in the second stage 908, each of the first UE 902A upto the Nth UE 902N may be configured to move over a plurality of different geographical areas within a radio cell of the base station 904. When each of the first UE 902A upto the Nth UE 902N moves over the plurality of different geographical areas, each of the first UE 902A upto the Nth UE 902N may be configured to communicate its respective position heading towards the base station 904 through the assigned beam. After receiving the position of each of the first UE 902A upto the Nth UE 902N, the base station 904 may be configured to measure received power over the plurality of different geographical areas and swap the beams among each of the first UE 902A upto the Nth UE 902N. Therefore, the third stage 910 may also be referred to as training phase which is performed at 5G NR FR1 as well as 5G NR FR2 (i.e. 24.25 GHz to 52.6 GHz). After the third stage 910 (i.e, after the the training phase), the base station 904 may be configured to assign an improved spatial direction to a next UE entering the radio cell of the base station 904.

In the flowchart 900, each of the first UE 902A upto the Nth UE 902N may be configured to support N spatial directions and the base station 904 may be configured to support M spatial directions. Thus, the beam assignement at the first UE 902A may be written in terms of M and N as (M-1)*N+1 and the at the Nth UE 902N as M*N.

FIG. 10 is an illustarion of an exemplary scenario of communication between a base station and a user equipment, in accordance with an embodiment of the present disclosure. FIG. 10 is described in conjunction with elements from FIGs. 1 to 6, 7A to 7E, 8A, 8B, and 9. With reference to FIG. 10, there is shown an exemplary scenario 1000 of communication between the base station 904 and the first UE 902A (i.e. UEi). There is further shown operations 1002-1016 in the exemplary scenario 1000.

At operation 1002, the first UE 902A is configured to communicate its antenna capability information to the base station 904 during the initial access which is performed at 5G NR FR1. At operation 1004, after receiving the antenna capability information of the first UE 902A, the base station 904 is configured to assign a fixed beam to the first UE 902A for information transmission.

At operation 1006, after receiving the fixed beam, the first UE 902A is configured to transmit the information, such as a training preamble to the base station 904 using the 5G NR FR2 when the first UE 902A moves over a plurality of different geographical areas within radio cell of the base station 904.

At operation 1008, the first UE 902A is configured to transmitadditional information, such as its position and/or orientation to the base station 904 using the 5G NR FR1 when the first UE 902A moves over the plurality of different geographical areas within radio cell of the base station 904. In some embodiments, there is no need to transmit position. For example, the first UE 902A may be configured to execute the operations 1006 and 1008, when the first UE 902A moves in a first geographical area (e.g. vi). After receiving the information form the first UE 902A, the base station 904 may be configured to measure received power for the first geographical area and assign a beam pair (e.g. l,k) to the first UE 902A.

At operation 1010, the first UE 902A is configured to transmit the information, such as training preamble to the base station 904 using the 5G NR FR2 when the first UE 902A moves over the plurality of different geographical areas.

At operation 1012, the first UE 902A is configured to transmit more information, such as its position and orientation to the base station 904 using the 5G NR FR1 when the first UE 902A moves over the plurality of different geographical areas within radio cell of the base station 904. For example, the first UE 902A may be configured to execute the operations 1010 and 1012, when the first UE 902A moves in a second geographical area (e.g. V2). After receiving the information form the first UE 902A, the base station 904 may be configured to measure received power for the second geographical area and assign another beam pair (e.g. l,k) to the first UE 902A.

Similar to the operations 1010 and 1012, the first UE 902A may be configured to execute the operations 1014 and 1016 as the first UE 902 A moves over another geographical area within radio cell of the base station 904. Thus, the first UE 902A continuously transmit the information (i.e. training preamble, and optionally position and orientation) to the base station 904 as the first UE 902A moves over the plurality of different geographical areas (i.e. the first geographical area and the second geographical area) within the radio cell of the base station 904. Similar to the first UE 902A, the base station 904 may be configured to receive the information from N number of user equipments (e.g. UE2, UE3, UE4 upto UE_N). Thus, the base station 904 may be configured to measure received power (e.g., signal strength measurement value) for each cluster of the N number of UEs, orientation (e.g. m) of the N number of UEs and accordingly assign an improved beam pair to each cluster and each UE orientation. The base station 904 may also be referred to as a fusion center.

FIG. 11A is an illustration that depicts various parameters of a wireless channel, in accordance with an embodiment of the present disclosure. FIG. 11A is described in conjunction with elements from FIGs. 1 to 6, 7Ato 7E, 8 A, 8B, 9, and 10. With reference to FIG. 11 A, there is shown an exemplary representation 1100A of a wireless channel which is represented using a mathematical expression 1102.

The mathematical expression 1102 of the wireless channel (H(f)) includes an amplitude component 1102 A (cr_p(f)), a space component 1102B (a(0_p)) and a time component 1102C (g ^r(r_p)). The space component 1102B may be used as an antenna array spatial filters represented in a first box 1104. The first box 1104 is used to illustrate various phases (q q₂, and q₃ ) of the space component 1102B. The time component 1102C may be used as a plurality of delayed transmitted waveforms represented in a second box 1106. The second box 1106 illustrates various time delays ( t₁,t₂ , ahά t₃ ). The mathematical expression 1102 of the wireless channel ( H(f) ) may be applied to a mmWave communication channel which is sparse and made of a few propagation modes which further depends on geometry of a scenario.

FIG. 11B is an illustration of an implementation scenario of a wireless channel, in accordance with an embodiment of the present disclosure. FIG. 11B is described in conjunction with elements from FIGs. 1 to 6, 7A to 7E, 8A, 8B, 9, 10, and 11 A. With reference to FIG. 11B, there is shown an implementation scenario 1100B of the mathematical expression 1102 of the wireless channel (of FIG. 11 A). The implementation scenario 1100B includes a first mobile scenario 1108 and a second mobile scenario 1110. There is further shown a first vehicle 1112, a second vehicle 1114 and a geographical area

1116

In the first mobile scenario 1108, the first vehicle 1112 may be configured to cross a point in the geographical area 1116. In the second mobile scenario 1110, the second vehicle 1114 may be configured to cross the same point in the geographical area 1116. In such situation, the space component 1102B and the time component 1102C are same for each of the first vehicle 1112, and the second vehicle 1114 crossing the same point. Alternatively stated, wireless channel ( H₂ ) of the first mobile scenario 1108 and wireless channel (H₂ ) of second mobile scenario 1110 differ only in the amplitude component 1102A (or quick amplitude variations between the rays).

FIG. 12 is an illustration of multiple vehicles crossing a same geographical area, in accordance with an embodiment of the present disclosure. FIG. 12 is described in conjunction with elements from FIGs. 1 to 6, 7A to 7E, 8A, 8B, 9, 10, 11 A, and 1 IB. With reference to FIG. 12, there is shown an illustration 1200 that inlcudes multiple vehicles, such as a first vehicle 1202, a second vehicle 1204, a third vehicle 1206 and a fourth vehicle 1208. Each of the first vehicle 1202, the second vehicle 1204, the third vehicle 1206 and the fourth vehicle 1208 may move over a geographical area 1210. Each of the first vehicle 1202, the second vehicle 1204, the third vehicle 1206 and the fourth vehicle 1208 moving across the geographical area 1210 share the same propagation modes 1212, therefore, the information obtained from channel estimation (i.e. LR channel estimation) of each vehicle may be re used to improve the channel estimation of future vehicles moving over the same geographical area 1210.

FIG. 13 is an illustration that depicts hybrid beam forming, in accordance with an embodiment of the present disclosure. FIG. 13 is described in conjunction with elements from FIGs. 1 to 6, 7A to 7E, 8A, 8B, 9, 10, 11 A, 11B, and 12. With reference to FIG. 13, there is shown an illustration 1300 that depicts hybrid beam forming. There is further shown a relatively large region 1302 and a small region 1304. Generally, the hybrid beam forming is defined as a technique that combines analog beamforming with digital precoding in order to intelligently form patterns (or beams) which may be transmitted by a large antenna array at transmitting end and the same process is used at receiving end in order to create desired receiver pattern. In case of the hybrid beam forming, the relatively large region 1302 is analog controlled by use of analog precoding and the small region 1304 is digitally controlled by use of digital precoding. A circuit architecture used for analog precoding and digital precoding is represented in a dashed box 1306.

FIG. 14 is an illustration of graphical representations that depicts variations of spectral efficiency with increase in number of vehicles and with signal -to-noise (SNR) per antenna, in accordance with an embodiment of the present disclosure. FIG. 14 is described in conjunction with elements from FIGs. 1 to 6, 7A to 7E, 8A, 8B, 9, 10, 11 A, 1 IB, 12, and 13. With reference to FIG. 14, there is shown two graphical representations, such as a first graphical representation 1400A and a second graphical representation 1400B. The first graphical representation 1400A illustrates variations of spectral efficiency with increase in number of vehicles. The second graphical representation 1400B illustrates variations of spectral efficiency with signal -to-noise (SNR) in decibels (dB) per antenna.

The first graphical representation 1400A includes an X-axis 1402 that represents a number of vehicles in range of 0 to 1000. The first graphical representation 1400A further includes a Y-axis 1404 that represents spectral efficiency in bits per second per hertz (bits/s/Hz).

With reference to the first graphical representation 1400 A, a first line 1406 represents a perfect channel knowledge (also represented as perfect CSI). The perfect channel knowledge is taken as an upper limit. A second line 1408 represents variation of the spectral efficiency with increase in the number of vehicles using a conventional approach named as joint space time (JST) approach. A third line 1410 represents variation of the spectral efficiency with increase in the number of vehicles using another conventional approach named as separate space time (SST) approach. A fourth line 1412 represents variation of the spectral efficiency with increase in the number of vehicles using a current single vehicle solution (LS).

The second graphical representation 1400B includes an X-axis 1414 that represents signal- to-noise (SNR) in decibels (dB) per antenna. The second graphical representation 1400B further includes a Y-axis 1416 that represents spectral efficiency in bits per second per hertz

(bits/s/Hz). With reference to the second graphical representation 1400B, a first line 1418 represents spectral efficiency achieved using a perfect channel knowledge (also represented as perfect CSI). The perfect channel knowledge is taken as an upper limit. A second line 1420 represents variations of spectral efficiency with SNR measured in (dB) per antenna using the conventional approach named as joint spacetime (JST) approach. A third line 1422 represents variation of the spectral efficiency with SNR measured in (dB) per antenna using the other conventional approach named as separate space time (SST) approach. A fourth line 1424 represents variation of the spectral efficiency with SNR measured in (dB) per antenna using a current single vehicle solution (LS).

The first graphical representation 1400A and the second graphical representation 1400B is obtained via simulation using a carrier frequency of 28GHz, signal bandwidth of 400 MHz and transmitted power of 10W. Moreover, the network node 102 is considered to have 4 panels and each panel includes 16x6 clusters. The UE 202 is considered to have 4 panels and each panel includes 4x4 clusters each. Additionally, for sake of simplicity, ulti-user interference is not considered in the simulation. However, the beneficial effects of an improved channel estimation are expected to reduce overall wireless network interference level providing further spectral efficiency gain and a reduction in power consumption as well.

Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or to exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure.

Claims

1. A network node (102), comprising: a first control circuitry (104) configured to: obtain antenna capability information of one or more user equipment, UEs, when the one or more UEs enter a first area of a radio cell of the network node (102); communicate a spatial direction to be used for transmission to each of the one or more UEs, wherein a corresponding spatial direction is set at each of the one or more UEs throughout its presence within the first area of the radio cell; obtain information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the first area of the radio cell; and cumulate information from multiple UEs until it is possible to determine channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell based on the information obtained from the one or more UEs, wherein the determined channel state information is used to determine one or more spatial directions to be communicated as the spatial directions to be used for transmission for UEs entering the first area of the radio cell of the network node (102) once channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area have been determined.

2. The network node (102) according to claim 1, wherein the determination of the channel state information for each of the plurality of different geographical areas comprises: determining a signal quality metric for each of the plurality of different geographical areas based on the received information; and determining, for each of the plurality of different geographical areas, a set of beam steering angles ranked based on the determined signal quality metric.

3. The network node (102) according to claim 2, wherein the first control circuitry (104) is further configured to generate a beam-mapping matrix comprising a plurality of signal strength measurements for each of the set of beam steering angles supported by the network node (102) and the one or more UEs and each of the plurality of different geographical areas within the radio cell, such that the signal strength measurements can be used as the signal quality metric.

4. The network node (102) according to any one of the preceding claims, wherein the first control circuitry (104) is further configured to estimate and store a dataset of analogue precoders, analogue combiners, and digital channel eigenmodes for the plurality of different geographical areas to perform the channel estimation for the next UE.

5. The network node (102) according to any one of the preceding claims, wherein the first control circuitry (104) is further configured to estimate each of the plurality of different geographical areas based on a reference system.

6. A network node (102) according to any one of the preceding claims, wherein the first control circuitry (104) is further configured to: obtain antenna capability information of one or more user equipment, UEs, when the one or more UEs enter a second area of the radio cell of the network node (102); communicate one spatial direction to each of the one or more UEs, wherein a corresponding spatial direction is set at each of the one or more UEs throughout its presence within the second area of the radio cell; obtain information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the second area of the radio cell; and determine channel state information for each of the plurality of different geographical areas within the second area of the radio cell based on the information obtained from the one or more UEs.

7. The network node (102) according to any of the preceding claims, wherein the obtained information is at least one of: a plurality of pilot symbols, a specific waveform taken from a predefined list, a narrowband signal or a chirp signal.

8. The network node (102) according to any one of the preceding claims, wherein the one or more spatial directions to be communicated as a spatial direction to a UE (202) indicate a fixed beam orientation to be used by the UE (202) throughout its presence within the first area of the radio cell.

9. A user equipment, UE (202), comprising: a second control circuitry (204) and an array of antenna (206), wherein the second control circuitry (204) is configured to control the array of antenna to: communicate antenna capability information of the UE (202) to a network node (102) deployed at a fixed location when the UE (202) enters a radio cell of the network node (102); obtain one or more spatial directions for transmission from the network node (102) to be used throughout the presence of the UE (202) within a first area of the radio cell; transmit information towards the one or more spatial directions for transmission obtained from the network node (102) as the UE (202) moves arbitrarily over a plurality of different geographical areas within the first area of the radio cell.

10. The UE (202) according to claim 9, wherein the second control circuitry (204) is further configured to perform an initial access operation for a radio frequency communication with the network node (102), wherein the antenna capability information, which comprises a plurality of spatial directions supported by the array of antenna of the UE (202), is communicated to the network node (102) during the initial access operation.

11. The UE (202) according to claim 10, wherein the initial access operation is performed to establish a mmWave communication with the network node (102).

12. The UE (202) according to any one of the claims 9 to 11, wherein the one or more spatial direction obtained from the network node (102) indicates a set of fixed beam orientation to be used by the UE (202) throughout its presence within the first area of the radio cell.

13. The UE (202) according to any one of the claims 9 to 12, wherein the second control circuitry (204) is further configured to control the array of antenna to communicate at least one of: a position of the UE (202) or the position as well as an orientation of the UE (202) to the network node (102).

14. The UE (202) according to any of the claims 9 to 13, wherein the second control circuitry (204) is further configured to control the array of antenna to: obtain a second set of one or more spatial directions from the network node (102) when the UE (202) enters a second area of the radio cell, the second area being different from the first area; set the second set of one or more spatial directions as an updated active spatial direction at the UE (202) throughout its presence within a second area of the radio cell; and transmit the information towards the updated active spatial directions obtained from the network node (102) as the UE (202) moves arbitrarily over a plurality of different geographical areas within the second area of the radio cell.

15. The UE (202) according to any of the claims 9 to 14, wherein the transmitted information is at least one of: a plurality of pilot symbols, a specific waveform taken from a predefined list, a narrowband signal or a chirp signal.

16. The UE (202) according to any one of the claims 9 to 15, wherein the transmitted information is used by the network node (102) to determine a channel state information for each of the plurality of different geographical regions, and wherein the channel state information for each of the plurality of different geographical regions is used by the network node (102) for a beam alignment for each of the plurality of different geographical regions for a next UE when the next UE moves in the plurality of different geographical regions within the radio cell of the network node (102).

17. The UE (202) according to any one of the claims 9 to 16, wherein the UE (202) is one of: a vehicle or a mobile device, and wherein the network node (102) is at least one of: a base station (702, 904), a road-side unit (713), or a repeater device.

18. A method (300) for use in a network node (102) for beam training and alignment, the method (300) comprising: obtaining, by the network node (102), antenna capability information of one or more user equipment, UEs, when the one or more UEs enters a first area of a radio cell of the network node (102); communicating, by the network node (102), one or more spatial directions to be used for transmission to each of the one or more UEs, wherein a corresponding one or more spatial directions is set at each of the one or more UEs throughout its presence within the first area of the radio cell; obtaining, by the network node (102), information from each of the one or more UEs as the one or more UEs moves over a plurality of different geographical areas within the first area of the radio cell; and cumulating information from multiple UEs until it is possible to determine channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area of the radio cell based on the information obtained from the one or more UEs, wherein the determined channel state information is used to determine one or more spatial directions to be communicated as the spatial directions to be used for transmission for UEs entering the first area of the radio cell of the network node (102) once channel state information for one or more spatial directions supported by UEs antenna capability in each of the plurality of different geographical areas within the first area have been determined.

19. A method (400) for use in a user equipment, UE (202), for beam training and alignment, the method (400) comprising: communicating, by the UE (202), antenna capability information of the UE (202) to a network node (102) deployed at a fixed location when the EE (202) enters a first area of a radio cell of the network node (102); obtaining, by the EE (202), one or more spatial directions for transmission from the network node (102) to be used throughout the presence of the EE (202) within a first area of the radio cell; and transmitting, by the EE (202), information towards the one or more spatial directions obtained from the network node (102) as the EE (202) moves arbitrarily over a plurality of different geographical areas within the first area of the radio cell, wherein the information is used for the beam training and alignment.