# US 12,192,785 B2 · Transmit/receive beam association in millimeter wave V2X

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- Number: US 12,192,785 B2
- Document ID: US12192785B2
- Status: Granted
- Kind: B2
- Application number: 16/714,478
- Filed: 2019-12-13
- Published: 2020-06-18
- Granted: 2025-01-07
- Earliest claimed: 2018-12-17
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Jose Edson Vargas; Tao Luo; Zhibin Wu; Makesh Pravin John Wilson; Sudhir Kumar Baghel; Shailesh Patil
- Web page: https://patentgrep.com/patent/US12192785B2

## CPC

- H04W 16/28: using beam steering
- H04B 7/022: Site diversity; Macro-diversity (using two or more spaced independent antennas H04B7/04)
- H04B 7/06968: {using quasi-colocation [QCL] between signals}
- H04B 7/088: {using beam selection}
- H04W 4/40: for vehicles, e.g. vehicle-to-pedestrians [V2P]
- H04W 74/0833: Random access procedures, e.g. with 4-step access
- H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals}
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04W 4/70: Services for machine-to-machine communication [M2M] or machine type communication [MTC]
- H04W 56/0025: {synchronizing potentially movable access points}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Disclosed are techniques for transmit/receive (TX/RX) beam association in millimeter wave (mmW) vehicle-to-everything (V2X) communications. In conventional wireless systems, a node (e.g., gNB) that manages wireless resources is typically stationary. This means that transmissions from the network node over the same TX beam using the same antenna array orientation can be assumed to be quasi-collocated (QCLed) and communications may be established using fixed-to-mobile beam management approach. However, if the transmitting node is mobile, a quasi-collocation (QCL) assumption may not be valid. To address issues due to mobility of the nodes that manage wireless resources, a mobile-to-mobile beam management approach is proposed.

## Claims

### Claim 1

A synchronization signal block (SSB) receiver, comprising:
a transceiver;
a memory; and
a processor communicatively coupled to the transceiver and the memory,
wherein the transceiver, the memory, and/or the processor are configured to:
receive, from an SSB transmitter, an SSB on an SSB receive (RX) beam in a transmitter-to-receiver (T2R) direction, the SSB comprising an SSB index corresponding to the SSB RX beam;
transmit, to the SSB transmitter, a physical random access channel (PRACH) preamble on a first receiver-to-transmitter (R2T) beam in a first R2T direction, the PRACH preamble being based on the SSB; and
transmit, to the SSB transmitter, the PRACH preamble on a second R2T beam in a second R2T direction different from the first R2T direction
when a Random Access Response (RAR) is not received from the SSB transmitter within an RAR response window subsequent to transmitting the PRACH preamble on the first R2T beam, and
when a quasi-collocation (QCL) flag is set to QCL invalid,
wherein the QCL flag is set to QCL valid when a QCL assumption is valid and is set to QCL invalid when the QCL assumption is not valid, the QCL assumption being valid when first and second SSB transmissions from the SSB transmitter are QCLed, and is invalid otherwise, the first SSB transmission being a transmission of an SSB beam corresponding to an SSB index k at a first time, and the second SSB transmission being a transmission of an SSB beam corresponding to the same SSB index k at a second time different from the first time.

### Claim 2 (depends on 1)

The SSB receiver of claim 1, wherein when the QCL flag is set to QCL invalid, the first R2T beam is aligned with the SSB RX beam, and the second R2T beam is not aligned with the SSB RX beam.

### Claim 3 (depends on 1)

The SSB receiver of claim 1,
wherein the QCL flag setting is preconfigured within the SSB receiver, and/or
wherein the transceiver, the memory, and/or the processor are configured to receive the QCL flag setting from the SSB transmitter.

### Claim 4 (depends on 3)

The SSB receiver of claim 3, wherein when the QCL flag setting is received from the SSB transmitter, the QCL flag setting is included in the SSB, in a remaining minimum system information (RMSI), and/or in an other system information (OSI) received from the SSB transmitter.

### Claim 5 (depends on 1)

The SSB receiver of claim 1, wherein the transceiver, the memory, and/or the processor are further configured to set the QCL flag from QCL valid to QCL invalid after a QCL window has passed, the QCL window indicating a duration that the QCL flag remains set to QCL valid and then set to QCL invalid thereafter.

### Claim 6 (depends on 5)

The SSB receiver of claim 5,
wherein the QCL window is preconfigured within the SSB receiver, and/or
wherein the transceiver, the memory, and/or the processor are configured to receive the QCL window from the SSB transmitter.

### Claim 7 (depends on 6)

The SSB receiver of claim 6, wherein when the QCL window is received from the SSB transmitter, the QCL window is included in the SSB, in a remaining minimum system information (RMSI), and/or in an other system information (OSI) received from the SSB transmitter.

### Claim 8 (depends on 1)

The SSB receiver of claim 1, wherein the transceiver, the memory, and/or the processor are further configured to:
retransmit, to the SSB transmitter, the PRACH preamble on the first R2T beam with increased power
when the RAR is not received from the SSB transmitter within the RAR response window subsequent to previously transmitting the PRACH preamble on the first R2T beam, and when the QCL flag is set to QCL valid.

### Claim 9 (depends on 1)

The SSB receiver of claim 1, wherein the transceiver, the memory, and/or the processor are further configured to:
receive, from the SSB transmitter, an SSB transmitter path route; and
estimate a location of the SSB transmitter based on the SSB transmitter path route,
wherein when the QCL flag is set to QCL invalid, the second R2T direction is such that the second R2T beam is transmitted towards the estimated location of the SSB transmitter.

### Claim 10 (depends on 9)

The SSB receiver of claim 9, wherein the SSB transmitter path route is included in the SSB, in a remaining minimum system information (RMSI), and/or in an other system information (OSI) received from the SSB transmitter.

### Claim 11 (depends on 1)

The SSB receiver of claim 1,
wherein the T2R direction of the SSB RX beam is a first T2R direction, and
wherein the transceiver, the memory, and/or the processor are further configured to:
receive, from the SSB transmitter, the RAR on a Msg2 RX beam in a second T2R direction; and
transmit, to the SSB transmitter, a radio resource control (RRC) connection request on a third R2T beam in a third R2T direction, the RRC connection request being based on the RAR, and
transmit, to the SSB transmitter, the RRC connection request on a fourth R2T beam in a fourth R2T direction different from the third R2T direction
when a RRC connection setup is not received from the SSB transmitter within an RRC response window subsequent to transmitting the RRC connection request on the third R2T beam, and
when the QCL flag is set to QCL invalid.

### Claim 12 (depends on 11)

The SSB receiver of claim 11, wherein when the QCL flag is set to QCL invalid, the third R2T beam is aligned with the Msg2 RX beam, and the fourth R2T beam is not aligned with the Msg2 RX beam.

### Claim 13 (depends on 11)

The SSB receiver of claim 11, wherein the transceiver, the memory, and/or the processor are further configured to:
retransmit, to the SSB transmitter, the RRC connection request on the third R2T beam with increased power when
when the RRC connection setup is not received from the SSB transmitter within an RRC response window subsequent to transmitting the RRC connection request on the third R2T beam, and
when the QCL flag is set to QCL valid.

### Claim 14 (depends on 11)

The SSB receiver of claim 11, wherein the transceiver, the memory, and/or the processor are further configured to:
receive, from the SSB transmitter, an SSB transmitter path route; and
estimate a location of the SSB transmitter based on the SSB transmitter path route,
wherein when QCL flag is set to QCL invalid, the fourth R2T direction is such that the fourth R2T beam is transmitted towards the estimated location of the SSB transmitter.

### Claim 15

A synchronization signal block (SSB) transmitter, comprising:
a transceiver;
a memory; and
a processor communicatively coupled to the transceiver and the memory,
wherein the transceiver, the memory, and/or the processor are configured to:
transmit, to an SSB receiver, an SSB on a first transmitter-to-receiver (T2R) in a first T2R direction, the SSB comprising an SSB index corresponding to the first T2R beam;
receive, from the SSB receiver, a physical random access channel (PRACH) preamble on a Msg1 RX beam in a receiver-to-transmitter (R2T) direction, the PRACH preamble being based on the SSB transmitted on the first T2R beam; and
transmit, to the SSB receiver, a Random Access Response (RAR) on a second T2R beam in a second T2R direction in response to receiving the PRACH preamble, the second T2R direction being different from the first T2R direction when a quasi-collocation (QCL) flag is set to QCL invalid,
wherein the QCL flag is set to QCL valid when a QCL assumption is valid and is set to QCL invalid when the QCL assumption is not valid, the QCL assumption being valid when first and second SSB transmissions from the SSB transmitter are QCLed, and is invalid otherwise, the first SSB transmission being a transmission of an SSB beam corresponding to an SSB index k at a first time, and the second SSB transmission being a transmission of an SSB beam corresponding to the same SSB index k at a second time different from the first time.

### Claim 16 (depends on 15)

The SSB transmitter of claim 15, wherein the first T2R beam is not aligned with the Msg1 RX beam when the QCL flag is set to QCL invalid.

### Claim 17 (depends on 15)

The SSB transmitter of claim 15, wherein the transceiver, the memory, and/or the processor are further configured to transmit, to the SSB receiver, a QCL flag setting of the QCL flag.

### Claim 18 (depends on 17)

The SSB transmitter of claim 17, wherein the transceiver, the memory, and/or the processor are configured to transmit the QCL flag setting in the SSB, in a remaining minimum system information (RMSI), and/or in an other system information (OSI).

### Claim 19 (depends on 17)

The SSB transmitter of claim 17, wherein the transceiver, the memory, and/or the processor are further configured to transmit, to the SSB receiver, a QCL window to indicate a duration that the QCL flag remains set to QCL valid and then set to QCL invalid thereafter.

### Claim 20 (depends on 19)

The SSB transmitter of claim 19, wherein the transceiver, the memory, and/or the processor are configured to transmit the QCL window in the SSB, in a remaining minimum system information (RMSI), and/or in an other system information (OSI).

### Claim 21 (depends on 17)

The SSB transmitter of claim 17, wherein the transceiver, the memory, and/or the processor are further configured to transmit an SSB transmitter path route to the SSB receiver.

### Claim 22 (depends on 21)

The SSB transmitter of claim 21, wherein the transceiver, the memory, and/or the processor are configured to transmit the SSB transmitter path route in the SSB, in a remaining minimum system information (RMSI), and/or in an other system information (OSI).

### Claim 23 (depends on 21)

The SSB transmitter of claim 21,
wherein the transceiver, the memory, and/or the processor are further configured to estimate the second T2R direction based on the SSB transmitter path route and the R2T direction of the Msg1 RX beam, and
wherein when the QCL flag is set to QCL invalid, the second T2R direction is such that the second T2R beam is transmitted towards a location of the SSB receiver.

### Claim 24 (depends on 15)

The SSB transmitter of claim 15,
wherein the R2T direction of the Msg1 RX beam is a first R2T direction, and wherein the transceiver, the memory, and/or the processor are further configured to:
receive, from the SSB receiver, a radio resource control (RRC) connection request on a Msg3 RX beam in a second R2T direction, the RRC connection request being based on the RAR, and
transmit, to the SSB receiver, an RRC connection setup on a third T2R beam in a third T2R direction in response to receiving the RRC connection request, the third T2R direction being different from the second T2R direction when the QCL flag is set to QCL invalid.

### Claim 25 (depends on 24)

The SSB transmitter of claim 24, wherein the second T2R beam is not aligned with the Msg3 RX beam when the QCL flag is set to QCL invalid.

### Claim 26 (depends on 24)

The SSB transmitter of claim 24,
wherein the transceiver, the memory, and/or the processor are further configured to estimate the third T2R direction based on a SSB transmitter path route and the second R2T direction of the Msg3 RX beam, and
wherein when QCL flag is set to QCL invalid, the third T2R direction is such that the third T2R beam is transmitted towards a location of the SSB receiver.

### Claim 27

A method performed by a synchronization signal block (SSB) receiver, the method comprising:
receiving, from an SSB transmitter, an SSB on an SSB receive (RX) beam in a transmitter-to-receiver (T2R) direction, the SSB comprising an SSB index corresponding to the SSB RX beam;
transmitting, to the SSB transmitter, a physical random access channel (PRACH) preamble on a first receiver-to-transmitter (R2T) beam in a first R2T direction, the PRACH preamble being based on the SSB; and
transmitting, to the SSB transmitter, the PRACH preamble on a second R2T beam in a second R2T direction different from the first R2T direction
when a Random Access Response (RAR) is not received from the SSB transmitter within an RAR response window subsequent to transmitting the PRACH preamble on the first R2T beam, and
when a quasi-collocation (QCL) flag is set to QCL invalid,
wherein the QCL flag is set to QCL valid when a QCL assumption is valid and is set to QCL invalid when the QCL assumption is not valid, the QCL assumption being valid when first and second SSB transmissions from the SSB transmitter are QCLed, and is invalid otherwise, the first SSB transmission being a transmission of an SSB beam corresponding to an SSB index k at a first time, and the second SSB transmission being a transmission of an SSB beam corresponding to the same SSB index k at a second time different from the first time.

### Claim 28 (depends on 27)

The method of claim 27, wherein when the QCL flag is set to QCL invalid, the first R2T beam is aligned with the SSB RX beam, and the second R2T beam is not aligned with the SSB RX beam.

### Claim 29 (depends on 27)

The method of claim 27, wherein the QCL flag setting is preconfigured within the SSB receiver, and/or is received from the SSB transmitter.

### Claim 30 (depends on 27)

The method of claim 27, further comprising:
setting the QCL flag from QCL valid to QCL invalid after a QCL window has passed, the QCL window indicating a duration that the QCL flag remains set to QCL valid and then set to QCL invalid thereafter.

### Claim 31 (depends on 27)

The method of claim 27, further comprising:
receiving, from the SSB transmitter, an SSB transmitter path route; and
estimating a location of the SSB transmitter based on the SSB transmitter path route,
wherein when the QCL flag is set to QCL invalid, the second R2T direction is such that the second R2T beam is transmitted towards the estimated location of the SSB transmitter.

### Claim 32 (depends on 27)

The method of claim 27,
wherein the T2R direction of the SSB RX beam is a first T2R direction, and
wherein the method further comprises:
receiving, from the SSB transmitter, the RAR on a Msg2 RX beam in a second T2R direction; and
transmitting, to the SSB transmitter, a radio resource control (RRC) connection request on a third R2T beam in a third R2T direction, the RRC connection request being based on the RAR, and
transmitting, to the SSB transmitter, the RRC connection request on a fourth R2T beam in a fourth second R2T direction different from the third R2T direction
when a RRC connection setup is not received from the SSB transmitter within an RRC response window subsequent to transmitting the RRC connection request on the third R2T beam, and
when the QCL flag is set to invalid.

### Claim 33

A method performed by a synchronization signal block (SSB) transmitter, the method comprising:
transmitting, to an SSB receiver, an SSB on a first transmitter-to-receiver (T2R) in a first T2R direction, the SSB comprising an SSB index corresponding to the first T2R beam;
receiving, from the SSB receiver, a physical random access channel (PRACH) preamble on a Msg1 RX beam in a receiver-to-transmitter (R2T) direction, the PRACH preamble being based on the SSB transmitted on the first T2R beam; and
transmitting, to the SSB receiver, a Random Access Response (RAR) on a second T2R beam in a second T2R direction in response to receiving the PRACH preamble, the second T2R direction being different from the first T2R direction when a quasi-collocation (QCL) flag is set to QCL invalid,
wherein the QCL flag is set to QCL valid when a QCL assumption is valid and is set to QCL invalid when the QCL assumption is not valid, the QCL assumption being valid when first and second SSB transmissions from the SSB transmitter are QCLed, and is invalid otherwise, the first SSB transmission being a transmission of an SSB beam corresponding to an SSB index k at a first time, and the second SSB transmission being a transmission of an SSB beam corresponding to the same SSB index k at a second time different from the first time.

### Claim 34 (depends on 33)

The method of claim 33, wherein the first T2R beam is not aligned with the Msg1 RX beam when the QCL flag is set to QCL invalid.

### Claim 35 (depends on 33)

The method of claim 33, further comprising:
transmitting, to the SSB receiver, a QCL flag setting of the QCL flag.

### Claim 36 (depends on 33)

The method of claim 33, further comprising:
transmitting, to the SSB receiver, a QCL window to indicate a duration that the QCL flag remains set to QCL valid and then set to QCL invalid thereafter.

### Claim 37 (depends on 33)

The method of claim 33, further comprising:
estimating the second T2R direction based on a SSB transmitter path route and the R2T direction of the Msg1 RX beam,
wherein when the QCL flag is set to QCL invalid, the second T2R direction is such that the second T2R beam is transmitted towards an estimated location of the SSB receiver.

### Claim 38 (depends on 33)

The method of claim 33, further comprising
receiving, from the SSB receiver, a radio resource control (RRC) connection request on a Msg3 RX beam in a second R2T direction, the RRC connection request being based on the RAR, and
transmitting, to the SSB receiver, an RRC connection setup on a third T2R beam in a third T2R direction in response to receiving the RRC connection request, the third T2R direction being different from the second T2R direction when the QCL flag is set to QCL invalid.