# US 12,224,839 B2 · Method for indicating a beam correspondence failure

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- Number: US 12,224,839 B2
- Document ID: US12224839B2
- Status: Granted
- Kind: B2
- Application number: 17/216,517
- Filed: 2021-03-29
- Published: 2022-09-29
- Granted: 2025-02-11
- Earliest claimed: 2021-03-29
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Vasanthan Raghavan; Juergen Cezanne; Junyi Li; Allen Minh-Triet Tran
- Web page: https://patentgrep.com/patent/US12224839B2

## CPC

- H04B 7/06966: {using beam correspondence; using channel reciprocity, e.g. downlink beam training based on uplink sounding reference signal [SRS]}
- H04B 7/088: {using beam selection}
- H04W 16/28: using beam steering
- H04W 24/08: Testing, {supervising or monitoring} using real traffic
- H04W 76/19: Connection re-establishment
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A first wireless communication device, such as a base station, may include separate transmit and receive antenna arrays. The separation between the transmit and receive antenna arrays may cause a direction of a transmit beam formed at the transmit antenna array to be different from a direction of a receive beam formed at the receive antenna array. The transmit and receive beams may be formed for communication with a second wireless communication device, such as a user equipment (UE). The described aspects enable the first wireless communication device to monitor a difference between a first direction of the transmit beam and a second direction of the receive beam. The first wireless communication device may transmit an indication of a beam correspondence failure to the second wireless communication device when the difference between the first and second directions is greater than or equal to a beam correspondence threshold.

## Claims

### Claim 1

A method for a first wireless communication device including a transmit antenna array and a receive antenna array, the transmit antenna array being separate from the receive antenna array, comprising:
forming a transmit beam in a first direction at the transmit antenna array and a receive beam in a second direction at the receive antenna array, wherein the transmit beam and the receive beam are formed for communication with a second wireless communication device;
wherein the first direction and the second direction point toward at least one object capable of passively reflecting, diffracting, or scattering wireless communication signals along a non-line of sight (NLOS) communication link to or from the second wireless communication device;
determining a signal strength threshold based on a difference between a peak gain value for the transmit beam or the receive beam and a threshold gain control value;
determining a beam correspondence threshold based on a beamwidth of the transmit beam or a beamwidth of the receive beam, wherein the beamwidth of the transmit beam or the beamwidth of the receive beam is determined based on the signal strength threshold for the transmit beam or the receive beam;
monitoring a difference between the first direction of the transmit beam and the second direction of the receive beam, wherein monitoring the difference comprises:
determining a distance from the transmit antenna array or the receive antenna array to the at least one object; and
determining a difference between the first direction and the second direction based on the distance from the transmit antenna array or the receive antenna array to the at least one object and a distance between the transmit antenna array and the receive antenna array; and
transmitting an indication of a beam correspondence failure to the second wireless communication device when the difference between the first direction and the second direction is greater than or equal to a beam correspondence threshold.

### Claim 2 (depends on 1)

The method of claim 1, wherein monitoring the difference between the first direction and the second direction is further based on at least one of a size of the transmit antenna array, a size of the receive antenna array, an arrangement of transmit antenna elements in the transmit antenna array, an arrangement of receive antenna elements in the receive antenna array, a set of beam weights associated with the transmit beam, and a set of beam weights associated with the receive beam.

### Claim 3 (depends on 1)

The method of claim 1, wherein the difference between the first direction and the second direction is an angle formed between the first direction and the second direction.

### Claim 4 (depends on 1)

The method of claim 1, wherein determining the distance from the transmit antenna array or the receive antenna array to the at least one object further comprises:
receiving, from the second wireless communication device, at least one of a path loss estimate or information indicating a location of the at least one object capable of reflecting, diffracting or scattering wireless communication signals; and
further determining the distance from the transmit antenna array or the receive antenna array to the at least one object based on the path loss estimate or the location of the at least one object capable of reflecting, diffracting or scattering wireless communication signals.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
transmitting an indication of the beam correspondence failure to the second wireless communication device when the distance is less than or equal to a distance threshold.

### Claim 6 (depends on 5)

The method of claim 5, wherein the distance threshold is a value based on at least one of a beamwidth of the transmit beam or the receive beam, a size of the transmit antenna array, a size of the receive antenna array, a spacing of transmit antenna elements in the transmit antenna array, a spacing of receive antenna elements in the receive antenna array, or a beamwidth factor.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
initiating a beam refinement training procedure for the receive beam or the transmit beam when the indication of the beam correspondence failure is transmitted to the second wireless communication device; and
determining a refined receive beam or a refined transmit beam based on the beam refinement training procedure.

### Claim 8 (depends on 7)

The method of claim 7, further comprising:
indicating, to the second wireless communication device, a mapping of control information for at least one beam when the indication of the beam correspondence failure is transmitted to the second wireless communication device.

### Claim 9 (depends on 8)

The method of claim 8, wherein the control information includes at least one of a synchronization signal block (SSB) index or a channel state information reference signal (CSI-RS) index.

### Claim 10 (depends on 1)

The method of claim 1, wherein the beamwidth corresponds to an intersection of the transmit beam or the receive beam and the signal strength threshold.

### Claim 11 (depends on 10)

The method of claim 10, wherein the intersection corresponds to a pair of angles where a beam pattern of the transmit beam or the received beam intersects the signal strength threshold.

### Claim 12 (depends on 1)

The method of claim 1, wherein, in response to the indication of a beam correspondence failure, performing separate beam training procedures to determine different transmit and receive beams.

### Claim 13 (depends on 1)

The method of claim 1, further comprising determining the location of the at least one object using ray tracing and map-based information.

### Claim 14 (depends on 1)

The method of claim 1, wherein the first wireless communication device comprises a base station.

### Claim 15

A first apparatus for wireless communication, comprising:
a transmit antenna array and a receive antenna array, the transmit antenna array being separate from the receive antenna array;
a memory; and
at least one processor coupled to the memory and configured to:
form a transmit beam in a first direction at the transmit antenna array and a receive beam in a second direction at the receive antenna array, wherein the transmit beam and the receive beam are formed for communication with a second apparatus;
wherein the first direction and the second direction point toward at least one object capable of passively reflecting, diffracting, or scattering wireless communication signals along a non-line of sight (NLOS) communication link to or from the second wireless communication device;
determine a signal strength threshold based on a difference between a peak gain value for the transmit beam or the receive beam and a threshold gain control value;
determine a beam correspondence threshold based on a beamwidth of the transmit beam or a beamwidth of the receive beam, wherein the beamwidth of the transmit beam or the beamwidth of the receive beam is determined based on the signal strength threshold for the transmit beam or the receive beam;
monitor a difference between the first direction of the transmit beam and the second direction of the receive beam, including configuring the at least one processor to:
determine a distance from the transmit antenna array or the receive antenna array to the at least one object; and
determine a difference between the first direction and the second direction based on the distance from the transmit antenna array or the receive antenna array to the at least one object and a distance between the transmit antenna array and the receive antenna array; and
transmit an indication of a beam correspondence failure to the second apparatus when the difference between the first direction and the second direction is greater than or equal to a beam correspondence threshold.

### Claim 16 (depends on 15)

The first apparatus of claim 15, wherein the at least one processor configured to monitor the difference between the first direction of the transmit beam and the second direction of the receive beam is further configured to:
further determine the difference between the first direction and the second direction based on at least one of a size of the transmit antenna array, a size of the receive antenna array, an arrangement of transmit antenna elements in the transmit antenna array, an arrangement of receive antenna elements in the receive antenna array, a set of beam weights associated with the transmit beam, and a set of beam weights associated with the receive beam.

### Claim 17 (depends on 15)

The first apparatus of claim 15, wherein the difference between the first direction and the second direction is an angle formed between the first direction and the second direction.

### Claim 18 (depends on 15)

The first apparatus of claim 15, wherein the at least one processor configured to determine the distance from the transmit antenna array or the receive antenna array to the at least one object is further configured to:
receive, from the second apparatus, at least one of a path loss estimate or information indicating a location of at least one object capable of reflecting, diffracting or scattering wireless communication signals; and
further determine the distance from the transmit antenna array or the receive antenna array to the at least one object based on the path loss estimate or the location of the at least one object capable of reflecting, diffracting or scattering wireless communication signals.

### Claim 19 (depends on 15)

The first apparatus of claim 15, wherein the at least one processor is further configured to:
transmit an indication of the beam correspondence failure to the second apparatus when the distance is less than or equal to a distance threshold.

### Claim 20 (depends on 15)

The first apparatus of claim 15, wherein the at least one processor is further configured to:
initiate a beam refinement training procedure for the receive beam or the transmit beam when the indication of the beam correspondence failure is transmitted to the second apparatus; and
determine a refined receive beam or a refined transmit beam based on the beam refinement training procedure.

### Claim 21 (depends on 20)

The first apparatus of claim 20, wherein the at least one processor is further configured to:
indicate, to the second apparatus, a mapping of control information for at least one beam when the indication of the beam correspondence failure is transmitted to the second apparatus.

### Claim 22 (depends on 15)

The first apparatus of claim 15, wherein the beamwidth corresponds to an intersection of the transmit beam or the receive beam and the signal strength threshold.

### Claim 23 (depends on 22)

The first apparatus of claim 22, wherein the intersection corresponds to a pair of angles where a beam pattern of the transmit beam or the received beam intersects the signal strength threshold.

### Claim 24 (depends on 15)

The first apparatus of claim 15, wherein, in response to the indication of a beam correspondence failure, the at least one processor is further configured to perform separate beam training procedures to determine different transmit and receive beams.

### Claim 25 (depends on 15)

The first apparatus of claim 15, wherein the at least one processor coupled to the memory and is further configured to determine the location of the at least one object using ray tracing and map-based information.

### Claim 26 (depends on 15)

The first apparatus of claim 15, wherein the first apparatus comprises a base station.

### Claim 27

A first apparatus for wireless communication including a transmit antenna array and a receive antenna array, the transmit antenna array being separate from the receive antenna array, comprising:
means for forming a transmit beam in a first direction at the transmit antenna array and a receive beam in a second direction at the receive antenna array, wherein the transmit beam and the receive beam are formed for communication with a second apparatus, and wherein the first direction and the second direction point toward at least one object capable of passively reflecting, diffracting, or scattering wireless communication signals along a non-line of sight (NLOS) communication link to or from the second wireless communication device;
means determining a signal strength threshold based on a difference between a peak gain value for the transmit beam or the receive beam and a threshold gain control value;
means for determining a beam correspondence threshold based on a beamwidth of the transmit beam or a beamwidth of the receive beam, wherein the beamwidth of the transmit beam or the beamwidth of the receive beam is determined based on the signal strength threshold for the transmit beam or the receive beam;
means for monitoring a difference between the first direction of the transmit beam and the second direction of the receive beam, wherein the means for monitoring comprises:
means for determining a distance from the transmit antenna array or the receive antenna array to the at least one object; and
means for determining a difference between the first direction and the second direction based on the distance from the transmit antenna array or the receive antenna array to the at least one object and a distance between the transmit antenna array and the receive antenna array; and
means for transmitting an indication of a beam correspondence failure to the second apparatus when the difference between the first direction and the second direction is greater than or equal to a beam correspondence threshold.

### Claim 28 (depends on 27)

The first apparatus of claim 27, wherein the first apparatus comprises a base station.

### Claim 29 (depends on 27)

The first apparatus of claim 27, further comprising means for determining the location of the at least one object using ray tracing and map-based information.

### Claim 30

A non-transitory computer-readable medium storing computer executable code, the code when executed by a processor causes the processor to:
form a transmit beam in a first direction at a transmit antenna array and a receive beam in a second direction at a receive antenna array, wherein the transmit antenna array is separate from the receive antenna array, and wherein the transmit beam and the receive beam are formed for communication with a wireless communication device;
wherein the first direction and the second direction point toward at least one object capable of passively reflecting, diffracting, or scattering wireless communication signals along a non-line of sight (NLOS) communication link to or from the second wireless communication device;
determine a signal strength threshold based on a difference between a peak gain value for the transmit beam or the receive beam and a threshold gain control value;
determine a beam correspondence threshold based on a beamwidth of the transmit beam or a beamwidth of the receive beam, wherein the beamwidth of the transmit beam or the beamwidth of the receive beam is determined based on the signal strength threshold for the transmit beam or the receive beam;
monitor a difference between the first direction of the transmit beam and the second direction of the receive beam, comprising code that causes the processor to:
determine a distance from the transmit antenna array or the receive antenna array to the at least one object;
determine a difference between the first direction and the second direction based on the distance from the transmit antenna array or the receive antenna array to the at least one object and a distance between the transmit antenna array and the receive antenna array; and
transmit an indication of a beam correspondence failure to the wireless communication device when the difference between the first direction and the second direction is greater than or equal to a beam correspondence threshold.