US-12621678-B2 - Beam management for antenna array

US12621678B2US 12621678 B2US12621678 B2US 12621678B2US-12621678-B2

Abstract

An apparatus, comprising at least one processor, and at least one memory storing instructions, the at least one memory and the instructions configured to, with the at least one processor, cause the apparatus to: determine a power angular spectrum characterizing a power distribution associated with an antenna array in a two-dimensional angular range, determine a beam aiming direction estimation and an associated confidence, determine estimates for an azimuthal angular spread, ASD, and an elevation angular spread, ZSD, determine a best beam shape and best beam aiming direction according to a predetermined criterion based on at least one of a) the power angular spectrum, b) the beam aiming direction estimation and the associated confidence, c) the estimate for the azimuthal angular spread, d) the estimate for the elevation angular spread.

Inventors

Jinfeng DU
Silvio MANDELLI

Assignees

NOKIA SOLUTIONS AND NETWORKS OY

Dates

Publication Date: 20260505
Application Date: 20230323
Priority Date: 20220412

Claims (12)

1 . An apparatus, comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions configured to, with the at least one processor, cause the apparatus to: determine a power angular spectrum (PAS) characterizing a power distribution associated with an antenna array in a predetermined angular range; determine a beam aiming direction estimation (DIR-EST) and an associated confidence (DIR-EST-CONF); determine estimates (ASD-EST, ZSD-EST) for at least one of an azimuthal angular spread, ASD, and an elevation angular spread, ZSD; determine a best beam shape (BS-BEST) and best beam aiming direction (AD-BEST) according to a predetermined criterion based on at least one of a) the power angular spectrum (PAS), b) the beam aiming direction estimation (DIR-EST) and the associated confidence (DIR-EST-CONF), c) the estimate (ASD-EST) for the azimuthal angular spread, d) the estimate (ZSD-EST) for the elevation angular spread; determine, based on the power angular spectrum (PAS), whether there is more than one dominant arrival cluster associated with the power angular spectrum (PAS); and determine an objective function (OBJ-FUNCT) based on the determination, whether there is more than one dominant arrival cluster.
2 . The apparatus according to claim 1 , wherein the instructions, when executed by the at least one processor, cause the apparatus to: Determine the objective function (OBJ-FUNCT) characterizing the best beam shape (BS-BEST) and the best beam aiming direction (AD-BEST) according to the predetermined criterion, determine the best beam shape (BS-BEST) and the best beam aiming direction (AD-BEST) based on the objective function (OBJ-FUNCT).
3 . The apparatus according to claim 1 , wherein the instructions, when executed by the at least one processor, cause the apparatus to perform beam sweeping (SWEEP-NAF) in a normalized angular frequency domain.
4 . The apparatus according to claim 3 , wherein the normalized angular frequency domain is characterized by φ=sin (θ)/2, wherein φ is a normalized angular frequency, wherein θ characterizes an angle between a boresight direction and a target direction.
5 . The apparatus according to claim 3 , wherein the instructions, when executed by the at least one processor, cause the apparatus to determine a sampling step size (SSS-NAF) for the beam sweeping (SWEEP-NAF) in the normalized angular frequency domain based on a number (N) of antenna elements and a scaling parameter (α) associated with a desired overlap threshold.
6 . The apparatus according to claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to: determine a predetermined number of n many best values associated with the power angular spectrum (PAS) for the predetermined angular range; determine if a specific one of the n many best values exceeds the other n−1 many best values by a predetermined threshold; and determine the beam aiming direction estimation (DIR-EST) and the associated confidence (DIR-EST-CONF) based on the determination.
7 . The apparatus according to claim 6 , wherein the instructions, when executed by the at least one processor, cause the apparatus to: repeat the steps of determining the predetermined number of n many best values associated with the power angular spectrum (PAS) for the predetermined angular range; determine if a specific one of the n many best values exceeds the other n−1 many best values by a predetermined threshold; and determine the beam aiming direction estimation (DIR-EST) and the associated confidence (DIR-EST-CONF) based on the determination, for a plurality of clusters of beams associated with the power angular spectrum (PAS).
8 . The apparatus according to claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to: determine K many best clusters (CLUST-K) of beams associated with the power angular spectrum (PAS); determine, for each of the K many best clusters of beams, a corresponding aiming direction estimation (DIR-EST-K) and an associated confidence (DIR-EST-CONF-K); determine, for each of the K many best clusters of beams, estimates (ASD-EST-K, ZSD-EST-K) for at least one of an azimuthal angular spread, ASD, and an elevation angular spread, ZSD; and determine, for each of the K many best clusters of beams, a respective beam (BEAM-K).
9 . The apparatus according to claim 1 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to determine at least one of the best beam shape (BS-BEST) and the best beam aiming direction (AD-BEST) based on at least one of the following elements: a) Reference Signal Strength Indicator, RSSI, b) Reference Signal Received Power, RSRP, c) Reference Signal Received Quality, RSRQ, d) Signal to Noise Ratio, SNR, e) Signal to Interference plus Noise Ratio, SINR.
10 . A method comprising: determining a power angular spectrum (PAS) characterizing a power distribution associated with an antenna array in a predetermined angular range; determining a beam aiming direction estimation (DIR-EST) and an associated confidence (DIR-EST-CONF); determining estimates (ASD-EST, ZSD-EST) for an azimuthal angular spread, ASD, and an elevation angular spread, ZSD; determining a best beam shape (BS-BEST) and best beam aiming direction (AD-BEST) according to a predetermined criterion based on at least one of a) the power angular spectrum (PAS), b) the beam aiming direction estimation (DIR-EST) and the associated confidence (DIR-EST-CONF), c) the estimate (ASD-EST) for the azimuthal angular spread, d) the estimate (ZSD-EST) for the elevation angular spread; determining, based on the power angular spectrum (PAS), whether there is more than one dominant arrival cluster associated with the power angular spectrum (PAS); and determining an objective function (OBJ-FUNCT) based on the determination, whether there is more than one dominant arrival cluster.
11 . A device for wireless applications, comprising at least one apparatus comprising: at least one processor; and at least one memory storing instructions, the at least one memory and the instructions configured to, with the at least one processor, cause the apparatus to: determine a power angular spectrum (PAS) characterizing a power distribution associated with an antenna array in a predetermined angular range, determine a beam aiming direction estimation (DIR-EST) and an associated confidence (DIR-EST-CONF); determine estimates (ASD-EST; ZSD-EST) for at least one of an azimuthal angular spread, ASD, and an elevation angular spread, ZSD; determine a best beam shape (BS-BEST) and best beam aiming direction (AD-BEST) according to a predetermined criterion based on at least one of a) the power angular spectrum (PAS), b) the beam aiming direction estimation (DIR-EST) and the associated confidence (DIR-EST-CONF), c) the estimate (ASD-EST) for the azimuthal angular spread, d) the estimate (ZSD-EST) for the elevation angular spread; determine, based on the power angular spectrum (PAS), whether there is more than one dominant arrival cluster associated with the power angular spectrum (PAS); and determine an objective function (OBJ-FUNCT) based on the determination, whether there is more than one dominant arrival cluster.
12 . A wireless communication system comprising at least one device according to claim 11 .

Description

CROSS REFERENCE TO RELATED APPLICATION This application claims the benefit of Finnish Patent Application No. 20225322, filed Apr. 12, 2022. The entire content of the above-referenced application is hereby incorporated by reference. FIELD OF THE DISCLOSURE Various example embodiments relate to an apparatus comprising at least one processor. Further embodiments relate to a method of operating related to such apparatus. BACKGROUND A growing demand of high-speed wireless transmission drives an expansion of e.g. cellular communication to higher frequency bands such as millimeter waves (mmWave), where comparatively wide spectrum (e.g. hundreds of MHz) is available. Large antenna arrays at mmWave can e.g. be used in 5G communication systems, and they may also be considered to be used with future 6G communication systems, for example in the mid and high frequency bands. Beam management of large antenna arrays can be complex. SUMMARY Various embodiments of the disclosure are set out by the independent claims. The exemplary embodiments and features, if any, described in this specification, that do not fall under the scope of the independent claims, are to be interpreted as examples useful for understanding various exemplary embodiments of the disclosure. Some embodiments relate to an apparatus, comprising at least one processor, and at least one memory storing instructions, the at least one memory and the instructions configured to, with the at least one processor, cause the apparatus to: determine a power angular spectrum characterizing a power distribution associated with an antenna array in a predetermined angular range, determine a beam aiming direction estimation and an associated confidence, determine estimates for at least one of an azimuthal angular spread, ASD, and an elevation angular spread, ZSD, determine a best beam shape and best beam aiming direction according to a predetermined criterion based on at least one of a) the power angular spectrum, b) the beam aiming direction estimation and the associated confidence, c) the estimate for the azimuthal angular spread, d) the estimate for the elevation angular spread. In some embodiments this facilitates beam management for the antenna array and can e.g. contribute to efficiently determine which beam shape(s) to use for the antenna array and/or where to point to with the respective beam(s). As an example, in some embodiments, the approach according to the principle according to the embodiments enables to provide a solution for joint beam direction finding and beam shape determination, e.g. optimization. In other words, in some embodiments, the problems related to determining which beam shape(s) to use for the antenna array and where to point to with the respective beam(s) may be jointly addressed thus e.g. enabling to efficiently increase a resilience, e.g. against beam misalignment errors, and to obtain an improved directional gain. In some embodiments, the predetermined angular range can be a one-dimensional angular range (e.g. characterizing one of an azimuth dimension or an elevation dimension) or a two-dimensional angular range (e.g. characterizing an azimuth dimension and an elevation dimension). In some embodiments, the apparatus may be configured to use a set of directional beams for beam sweeping, e.g. to obtain an estimation of the power angular spectrum (reflecting power distribution over angles), and to identify a, for example best, aiming direction and an associated estimation confidence, as well as angular spread (i.e., ASD and ZSD), e.g. along the identified, for example best, aiming direction. In some embodiments, the beam shape may e.g. be determined by maximizing an effective directional gain by accounting for both angular spread and aiming direction estimate confidence, given the estimated power angular spectrum. Further details and aspects related to azimuthal angular spread, ASD, and elevation angular spread, ZSD, are disclosed in WO 2020/212730 A1. In some embodiments, the apparatus may be an apparatus for a wireless communications network, e.g. according to the 5G and/or 6G type or of other types. In some embodiments, the apparatus and/or its functionality may e.g. be provided at a base station, e.g. gNB, for a cellular communications network. In some embodiments, the instructions, when executed by the at least one processor, cause the apparatus to: determine an objective function characterizing the best beam shape and the best beam aiming direction according to the predetermined criterion, determine the best beam shape and the best beam aiming direction based on the objective function. In some embodiments, the instructions, when executed by the at least one processor, cause the apparatus to perform beam sweeping, e.g. to determine the power angular spectrum, in a normalized angular frequency domain. In some embodiments, the normalized angular frequency domain is characterized by ϕ=sin⁡(θ)2, wherein φ is a normalized angular frequency,