Patent Description:
<CIT> discloses a method performed by a receiving node to reserve a directional channel, the method comprising: receiving a directional Request-to-Send (DRTS) message from a transmitting node; transmitting a directional Clear-to-Send (DCTS) message using one or more first beams, with at least one first beam being directed in a first direction towards the transmitting node; determining a second direction, the second direction being a different direction than the first direction; and transmitting at least one additional DCTS message using one or more second beams, with at least one second beam being directed in the second direction towards a potentially interfering node.

The invention is defined in the independent claims, to which reference should now be made.

In the following, the invention is best understood in view of <FIG>. The remaining embodiments, aspects, or examples are included in order to help the reader better understand the invention. In some aspects, a method of wireless communication, performed by a wireless node, may include performing a listen-before-talk (LBT) operation in a first direction and a second direction, wherein the second direction is opposite to the first direction, and wherein the LBT operation is performed using a first receive beam in the first direction and a second receive beam in the second direction; and selectively performing a transmission in the first direction based at least in part on a result of the LBT operation.

In some aspects, a wireless node for wireless communication may include memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to perform an LBT operation in a first direction and a second direction, wherein the second direction is opposite to the first direction, wherein the LBT operation is performed using a first receive beam in the first direction and a second receive beam in the second direction; and selectively perform a transmission in the first direction based at least in part on a result of the LBT operation.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a wireless node, may cause the one or more processors to perform an LBT operation in a first direction and a second direction, wherein the second direction is opposite to the first direction, wherein the LBT operation is performed using a first receive beam in the first direction and a second receive beam in the second direction; and selectively perform a transmission in the first direction based at least in part on a result of the LBT operation.

In some aspects, an apparatus for wireless communication may include means for performing an LBT operation in a first direction and a second direction, wherein the second direction is opposite to the first direction, wherein the LBT operation is performed using a first receive beam in the first direction and a second receive beam in the second direction; and means for selectively performing a transmission in the first direction based at least in part on a result of the LBT operation.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described with reference to and as illustrated by the drawings and specification.

Controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform one or more techniques associated with a bidirectional LBT operation, as described in more detail elsewhere herein. For example, controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform or direct operations of, for example, process <NUM> of <FIG> and/or other processes as described herein. Memories <NUM> and <NUM> may store data and program codes for base station <NUM> and UE <NUM>, respectively. In some aspects, memory <NUM> and/or memory <NUM> may comprise a non-transitory computer-readable medium storing one or more instructions for wireless communication. For example, the one or more instructions, when executed by one or more processors of the base station <NUM> and/or the UE <NUM>, may perform or direct operations of, for example, process <NUM> of <FIG> and/or other processes as described herein.

In some aspects, a wireless node (e.g., UE <NUM> or BS <NUM>) may include means for performing a listen-before-talk (LBT) operation in a first direction and a second direction, wherein the second direction is opposite to the first direction, wherein the LBT operation is performed using a first receive beam in the first direction and a second receive beam in the second direction; means for selectively performing a transmission in the first direction based at least in part on a result of the LBT operation; means for performing the LBT operation in the first direction and the second direction contemporaneously; means for performing the LBT operation in the first direction and the second direction sequentially; and/or the like. In some aspects, such means may include one or more components of UE <NUM> described in connection with <FIG>, such as controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, and/or the like. In some aspects, such means may include one or more components of BS <NUM> described in connection with <FIG>, such as antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, and/or the like.

Some wireless nodes, such as a wireless node in a non-centrally-scheduled deployment (e.g., an unlicensed spectrum deployment, a sidelink network, and/or the like) may perform a listen-before-talk (LBT) operation to determine whether a channel has sufficient available resources to perform a communication. LBT may be an abbreviation of listen-before-talk or listen-before-transmit. Listen-before-talk is used interchangeably with listen-before-transmit herein. In an LBT operation, a wireless node may listen to a desired frequency resource for a period of time. If the desired resource is not reserved by another wireless node in that time, or if interference and noise on the desired resource do not satisfy a threshold (e.g., if there is not too much interference or noise on the desired resource), then the wireless node may reserve the resource and perform a communication on the resource.

A wireless node may improve transmission or reception performance by performing beamforming. For example, a transmitting device may generate a transmit beam directed to a receiving device, and the receiving device may generate a receive beam directed to a cluster associated with the transmit beam. Beamforming may improve gain relative to a widebeam or omni-directional transmission approach.

A directional LBT operation is an LBT operation in which a wireless node uses a receive beam, directed to a target wireless node, to determine whether channel conditions are acceptable for a transmission to the target wireless node. For example, if a wireless node A desires to perform a transmission to a wireless node D in direction X, the wireless node A may generate a receive beam in direction X, and may perform an LBT operation using the receive beam. If the LBT operation is successful (e.g., if the node A does not sense any active transmission by another node), the wireless node A may use a transmit beam to perform the transmission to the wireless node D.

However, a successful LBT operation in direction X may not guarantee an unoccupied channel for the transmission from the wireless node A to the wireless node D. For example, if another wireless node C is located in the -X direction (the direction opposite from direction X) from the wireless node A, and if the wireless node C directs a communication to the wireless node B in the X direction, the wireless node A may not detect the communication, because wireless node A's receive beam is directed to direction X and hence cannot receive any transmissions in other directions and in particular in direction X, and due to blockage of the wireless node C's signal by components of the wireless node A. For example, if the beam in direction X is directed outward from the back of a UE, then the glass or screen would block signals from the negative X direction. This may cause interference or collision between the wireless node A and the wireless node C.

Some techniques and apparatuses described herein provide a bi-directional LBT operation for a wireless node to determine whether a channel is clear for a transmission to another wireless node. For example, continuing to use the notation from the above example, the wireless node A may perform the LBT operation in the X direction and the -X direction (e.g., using respective receive beams). Thus, the wireless node A may determine whether the channel is clear with respect to the wireless node B and with respect to the wireless node C. This improves the efficacy of the LBT operation and reduces the likelihood of interference from wireless node C (or any wireless node located opposite from the wireless node A's LBT operation target).

<FIG> is a diagram illustrating an example <NUM> of a procedure for a bidirectional LBT operation, in accordance with various aspects of the present disclosure. As shown, <FIG> depicts a Node A, a Node B, a Node C, and a Node D. The nodes A, B, C and D may be wireless nodes (e.g., UE <NUM> or BS <NUM>).

As shown in <FIG>, and by reference number <NUM>, the Node A may perform a bidirectional LBT operation in a first direction and a second direction. For example, the Node A may perform the bidirectional LBT operation to determine whether a transmission in the direction towards the Node D can be performed. The LBT operation in the first direction is shown by reference number <NUM>, and the LBT operation in the second direction is shown by reference number <NUM>. The first direction and the second direction may be opposite from each other. For example, if the first direction is the X direction, the second direction may be the -X direction (e.g., diametrically opposed from the first direction). In some aspects, the Node A may determine that an LBT operation is to be performed for the Node D, and may perform the bidirectional LBT operation based at least in part on determining that the LBT operation is to be performed for the Node D. The LBT operation referred to herein may be an LBT listen operation, such as a Category <NUM> LBT operation, a Category <NUM> LBT operation, and/or the like.

The Node A may perform the bidirectional LBT operation to detect potential interference from the Node C (shown by reference number <NUM>) and to detect potential interference from the Node B (shown by reference number <NUM>). As shown in <FIG>, Node C is transmitting to Node B, and thus Node B cannot cause interference to Node A's transmission. However, if Node B was transmitting to Node C (e.g., the opposite of what is depicted in <FIG>), then Node B can cause interference to Node A's transmission, so it may be beneficial to perform LBT operation in direction X. In other words, Node A may not know which node is transmitting to which node, so bidirectional LBT may be beneficial. For example, the Node C's transmission to Node B will cause interference to Node A's target node (Node D) because Node C's direction of transmission is the same as Node A's direction of transmission, though the interference may be caused by other factors in addition to or as an alternative to these transmissions. The interference from the Node B and/or the Node C may be caused by omni-directional transmissions, pseudo-omni-directional transmissions, beamformed transmissions, or a combination thereof.

As shown by reference number <NUM>, the Node A may selectively transmit to the Node D based at least in part on a result of the bidirectional LBT operation. For example, if the bidirectional LBT operation indicates that the channel is available with regard to the Node B and the Node C (i.e., in beam formed directions X and -X), then the Node A may transmit to the Node D by generating a transmit beam directed to the Node D. If the bidirectional LBT operation indicates that the channel is not available with regard to at least one of the Node B or the Node C (i.e., in beam formed directions X and -X), then the Node A may not transmit to the Node D (e.g., may perform a later LBT operation to identify a subsequent transmit opportunity). In some aspects, the Node A may configure a parameter of a transmission to the Node D based at least in part on the result of the bidirectional LBT operation. For example, if the channel is available but with some level of interference from the Node B or the Node C (i.e., in beam formed directions X or -X), the Node A may configure the transmission to the Node D such that a signal of the transmission overcomes the level interference from the Node B or the Node C.

In this way, the Node A may perform a bidirectional LBT operation, which may identify interference generated by a wireless node in the direction of the target wireless node or by a node in the opposite direction from the target wireless node. This reduces interference in sidelink deployments and improves radio performance of the Node A.

<FIG> is a diagram illustrating an example <NUM> of intra-UE signaling for a bidirectional LBT operation, in accordance with various aspects of the present disclosure. The operations described in connection with <FIG> are shown as being performed by a UE <NUM>, though these operations may be performed by any wireless node, such as another wireless node described herein. Furthermore, while the operations described in connection with <FIG> are described as being performed by particular protocol layers, such as the media access control layer and the physical layer, these operations may be performed by any layer of the UE <NUM>.

As shown by reference number <NUM>, a media access control (MAC) layer of the UE <NUM> may determine that a directional LBT operation is to be performed on the Node D (continuing the notation from <FIG>) in a direction X. For example, the MAC layer may determine that the UE <NUM> is to perform a transmission to the Node D, and/or the like. Accordingly, the MAC layer may provide an indication to a physical (PHY) layer of the UE <NUM> that the UE <NUM> is to perform the directional LBT operation.

As shown by reference number <NUM>, the PHY layer may trigger (e.g., perform) a bidirectional LBT in the X and -X directions. For example, the PHY layer triggers the bidirectional LBT operation based at least in part on the indication from the MAC layer to perform the directional LBT operation. Thus, the PHY layer performs a bidirectional LBT operation based at least in part on an indication to perform a non-bidirectional LBT operation. In some aspects, the MAC layer may provide an indication that the bidirectional LBT operation is to be performed.

As shown by reference number <NUM>, a first antenna subarray of the UE <NUM> (shown as Subarray A) may form a first set of beams (e.g., one or more receive beams) for the bidirectional LBT operation. As shown by reference number <NUM>, a second antenna subarray of the UE <NUM> (shown as Subarray B) may form a second set of beams (e.g., one or more receive beams) for the bidirectional LBT operation. For example, the first set of beams may be directed in the X direction and the second set of beams may be directed in the -X direction. In some aspects, Subarray A and Subarray B may be located on opposite sides of the UE <NUM>, or may be capable of directing beams in opposite directions. Subarray A and Subarray B may be part of the same antenna module or different antenna modules.

In some aspects, the UE <NUM> may perform the LBT operations shown by reference numbers <NUM> and <NUM> contemporaneously (e.g., at a same time, at substantially a same time, simultaneously, and/or the like). For example, if the UE <NUM> is capable of performing multiple contemporaneous LBT operations, then the UE <NUM> may perform the two LBT operations contemporaneously, which may reduce delay associated with the LBT operations. In some aspects, the UE <NUM> may perform the LBT operations shown by reference numbers <NUM> and <NUM> sequentially. For example, if the UE <NUM> is not capable of or configured to perform multiple contemporaneous LBT operations, or if the UE <NUM> determines that the multiple LBT operations are not to be performed contemporaneously, the UE <NUM> may perform the LBT operations sequentially. This may be less resource-intensive than contemporaneous LBT operation performance.

A beam that is referred to herein as being directed in a direction should be understood to be directed substantially in the direction (e.g., some deviation from the direction is contemplated).

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a wireless node, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where a wireless node (e.g., BS <NUM>, UE <NUM>, Node A, Node B, Node C, and/or the like) performs operations associated with a bidirectional LBT operation.

As shown in <FIG>, in some aspects, process <NUM> may include performing an LBT operation in a first direction and a second direction, wherein the second direction is opposite to the first direction, and wherein the LBT operation is performed using a first receive beam in the first direction and a second receive beam in the second direction (block <NUM>). For example, the wireless node (e.g., using antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, and/or the like) may perform an LBT operation (e.g., a bidirectional LBT operation) in a first direction and a second direction, as described above. In some aspects, the second direction is opposite to the first direction. In some aspects, the LBT operation is performed using a first receive beam in the first direction and a second receive beam in the second direction.

As further shown in <FIG>, in some aspects, process <NUM> may include selectively performing a transmission in the first direction based at least in part on a result of the LBT operation (block <NUM>). For example, the wireless node (e.g., using controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, and/or the like) may selectively perform a transmission in the first direction based at least in part on a result of the LBT operation, as described above.

In a first aspect, the LBT operation is performed using at least one of a plurality of beams, including the first receive beam, in the first direction, or a plurality of beams, including the second receive beam, in the second direction.

In a second aspect, alone or in combination with the first aspect, when the LBT operation results in detection of a threshold level of interference in either of the first direction or the second direction, the transmission is not performed.

In a third aspect, alone or in combination with one or more of the first and second aspects, the LBT operation comprises an LBT listen operation.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, performing the LBT operation in the first direction and the second direction is based at least in part on an indication from a media access control layer of the wireless node to a physical layer of the wireless node. In some aspects, the physical layer of the wireless node configures the LBT operation in the first direction and in the second direction.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, performing the LBT operation further comprises performing the LBT operation in the first direction and the second direction contemporaneously.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the LBT operation is performed using different subarrays of the wireless node.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, performing the LBT operation further comprises performing the LBT operation in the first direction and the second direction sequentially.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the transmission is a sidelink transmission.

<FIG> is a block diagram of an example apparatus <NUM> for wireless communication. The apparatus <NUM> may be a wireless node, or a wireless node may include the apparatus <NUM>. In some aspects, the apparatus <NUM> includes a reception component <NUM> and a transmission component <NUM>, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus <NUM> may communicate with another apparatus <NUM> (such as a UE, a base station, or another wireless communication device) using the reception component <NUM> and the transmission component <NUM>. As further shown, the apparatus <NUM> may include an LBT component <NUM>.

In some aspects, the apparatus <NUM> may be configured to perform one or more operations described herein in connection with <FIG>. Additionally or alternatively, the apparatus <NUM> may be configured to perform one or more processes described herein, such as process <NUM> of <FIG>. In some aspects, the apparatus <NUM> and/or one or more components shown in <FIG> may include one or more components of the wireless node described above in connection with <FIG>. Additionally, or alternatively, one or more components shown in <FIG> may be implemented within one or more components described above in connection with <FIG>. Additionally or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of the component.

In some aspects, the reception component <NUM> may include one or more antennas, a demodulator, a MIMO detector, a receive processor, a controller/processor, a memory, or a combination thereof, of the wireless node described above in connection with <FIG>.

In some aspects, the transmission component <NUM> may include one or more antennas, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the wireless node described above in connection with <FIG>.

The LBT component <NUM> (e.g., using the reception component <NUM> and/or the transmission component <NUM>) may perform a listen-before-talk (LBT) operation in a first direction and a second direction, wherein the second direction is opposite to the first direction. In some aspects, the LBT component <NUM> may perform the LBT operation in the first direction and the second direction contemporaneously. In some aspects, the LBT component <NUM> may perform the LBT operation in the first direction and the second direction sequentially. The transmission component <NUM> may selectively perform a transmission in the first direction based at least in part on a result of the LBT operation.

Claim 1:
A method of wireless communication performed by a wireless node, the method comprising:
performing (<NUM>) a bidirectional listen-before-talk, LBT, operation in a first direction and a second direction, wherein the second direction is opposite to the first direction,
wherein the bidirectional LBT operation is performed using a first receive beam in the first direction and a second receive beam in the second direction, and
wherein performing the bidirectional LBT operation in the first direction and the second direction is based at least in part on an indication, from a media access control layer of the wireless node to a physical layer of the wireless node, to perform a directional LBT operation, and wherein the physical layer of the wireless node configures the bidirectional LBT operation in the first direction and in the second direction; and
selectively performing (<NUM>, <NUM>) a transmission in the first direction based at least in part on a result of the bidirectional LBT operation.