Abstract: Wireless communications systems and methods related to over-the-air uplink-downlink (UL-DL) reciprocity calibration. A central unit transmits downlink (DL) calibration reference signal (RS) and a calibration request. The central unit receives, in response to the calibration request, a first uplink (UL) calibration RS and a first DL channel estimate associated with a first transmission point (TP) and a first wireless communication device. The central unit transmits a DL coordinated multipoint (CoMP) joint transmission signal according to an uplink-downlink (UL-DL) reciprocity calibration. The UL-DL reciprocity calibration is based on at least a first UL channel estimate based on the first UL calibration RS, the first DL channel estimate, a second UL channel estimate associated with a second TP and the first wireless communication device, and a second DL channel estimate associated with the second TP and the first wireless communication device.

Abstract: Aspects of the disclosure relate to wireless communication systems configured to share a shared spectrum with one or more other systems (e.g., other operator networks utilizing the same radio access technology, and/or other networks utilizing different radio access technologies). Coexistence between the different systems on the shared spectrum may be provided by utilizing a technology-neutral signature waveform such as a signature sequence or discovery signal. The signature sequence may be used for resource reservation, scheduling, and coordination among disparate systems operating on a shared spectrum. Other aspects, embodiments, and features are also claimed and described.

Abstract: Certain aspects of the present disclosure provide techniques for MCS and/or rank selection for UE jointly served by BSs in a CoMP cluster. As described herein, MCS and/or rank selection may be based, at least in part, on the inter-cluster interference and intra-cluster interference experienced by the UE. According to aspects, a CoMP scheduler may assign a UE served by BSs in a CoMP cluster to one of a first group of UEs or a second group of UEs based, at least in part, on inter-cluster and intra-cluster interference experienced by the UE. The scheduler may assign at least one of a MCS or rank selection to the UE based, at least in part, on the assigned group. The scheduler may provide an indication, to one or more BSs in the CoMP cluster, of the at least one MCS or rank selection assigned to the UE.

Abstract: Techniques are described for wireless communication. One method includes identifying a plurality of counters used to contend for access to a plurality of channels of an unlicensed radio frequency spectrum band. Each of the plurality of counters is associated with a respective channel of the plurality of channels of the unlicensed radio frequency spectrum band. The method also includes measuring at least one channel of the plurality of channels of the unlicensed radio frequency spectrum band. The measuring is associated with a contention for access to the at least one channel of the unlicensed radio frequency spectrum band. The method also includes synchronizing or desynchronizing at least a subset of the plurality of counters based at least in part on the measuring.

Abstract: Aspects of the disclosure relate to reserving resources in wireless communication systems, such as those employing listen before talk (LBT). The disclosed methods and apparatus employ a channel reservation preamble used in a sequence of burst or data packet transmissions. The preamble including a channel reservation indication is included in a first data packet transmitted from a first network node. The channel reservation indication is configured to indicate a transmission time reservation of channel resources covering the data packet containing the preamble, a second data packet to be received from a second network node responsive to the first data packet, and at least a portion of a third data packet transmitted from the first network node subsequent to the transmission of the second data packet. In this manner, over-reservation of channel resources is mitigated. Other aspects, embodiments, and features are also claimed and described.

Abstract: Certain aspects of the present disclosure provide techniques for protecting overhead and common channel transmissions in a NR shared spectrum system. A BS of a first operator may receive information regarding at least one overhead transmission associated with a wireless device of a second operator and may protect one or more overhead signal transmissions of the wireless device based, at least in part, on the received information. A UE may detect information associated with at least one overhead transmission from a wireless device associated with a first operator and may transmit the information regarding the detected overhead transmission to a BS associated with a second operator. A UE served by a BS associated with a first operator may detect a wireless device (e.g., another UE or a BS) associated with a second operator. The UE may report an identification of the wireless device to the BS.

Abstract: Techniques for overlapping cluster architecture for coordinated multipoint (CoMP) are provided. According to certain aspects, a method of wireless communication by a transmission point is provided. The method generally includes receiving, from a first base station, a first signal for a first user equipment (UE) to transmit over the air, receiving, from a second base station, a second signal for a second UE to transmit over the air, and combining the first and the second signals from the first and second base stations and transmitting the combined signal to the first and second UE.

Abstract: Various aspects described herein relate to techniques for communications in a coordinated multi-point (CoMP) wireless communications system. In an aspect, a method of wireless communications may include transmitting, by a user equipment (UE), reference signal (RS) measurements for forming a CoMP cluster, receiving, at the UE from at least a base station in the CoMP cluster, a message including information of at least a first cyclic prefix (CP) length for a first uplink transmission, wherein at least the first CP length for the first uplink transmission is different from a second CP length used for a second uplink transmission, and transmitting, by the UE, the first uplink transmission using at least the first CP length. The techniques described herein may apply to different communications technologies, including 5th Generation (5G) New Radio (NR) communications technology.

Abstract: Various aspects of the disclosure relate to communicating control information for independent links. For example, control information for one link may be sent via at least one other link. In some aspects, the independent links may involve a first device (e.g., a user equipment) communicating via different independent links with different devices (e.g., transmit receive points (TRPs) or sets of TRPs). In some scenarios, one link may carry control information for multiple links. For example, one link may indicate the existence of or traffic on at least one other link. As another example, one link may transmit feedback for multiple links. In some scenarios, each link may be provisioned (e.g., as a primary link or a secondary link) to carry specific types of control information for one or more links.

Abstract: Various aspects of the disclosure relate to power control for independent links. For example, power control at a device may be based on transmissions on multiple links. In some aspects, the independent links may involve a first device (e.g., a user equipment) communicating via different independent links with different devices (e.g., transmit receive points (TRPs) or sets of TRPs). For example, the first device may communicate with a second device (e.g., a TRP) via a first link and communicate with a third device (e.g., a TRP) via a second link. In some scenarios, power control for the first device may be based on power control commands received on multiple links. In some scenarios, a power control constraint may be met taking into account the transmission power on multiple links.

Abstract: Various aspects of the disclosure relate to channel sensing for independent links. In some aspects, the independent links may involve a first device (e.g., a user equipment) communicating via different independent links with different devices (e.g., transmit receive points (TRPs) or sets of TRPs). For example, the first device may communicate with a second device (e.g., a first TRP) via a first link and communicate with a third device (e.g., a second TRP) via a second link. In some scenarios, first channel sensing information may be obtained for the first link and second channel sensing information may be obtained for the second link. In some aspects, a decision of whether to transmit via one or more of the links may be based on the channel sensing on one or more of the links. In some cases, the links may be grouped together as a channel sensing group.

Abstract: Various aspects of the disclosure relate to event triggers for independent links. For example, an event trigger may be based on measurements from multiple links. In some aspects, the independent links may involve a first device (e.g., a user equipment) communicating via different independent links with different devices (e.g., transmit receive points (TRPs) or sets of TRPs). For example, the first device may communicate with a second device (e.g., a TRP) via a first link and communicate with a third device (e.g., a TRP) via a second link. In some scenarios, an event trigger may be based on aggregated measurements from multiple links.

Abstract: Various aspects of the disclosure relate to beam information for independent links. For example, beam information for one link may be sent on at least one other link. In some aspects, the independent links may involve a first device (e.g., a user equipment) communicating via different independent links with different devices (e.g., transmit receive points (TRPs) or sets of TRPs). For example, the first device may communicate with a second device (e.g., a TRP) via a first link and communicate with a third device (e.g., a TRP) via a second link. In some scenarios, one link can indicate beam switching for at least one other link. In some scenarios, one link can indicate link recovery for at least one other link. In some scenarios, one link can indicate link failure for at least one other link.

Abstract: Various aspects of the disclosure relate to feedback for independent links. For example, channel state feedback may be based on the channel state of multiple links. In some aspects, the independent links may involve a first device (e.g., a user equipment) communicating via different independent links with different devices (e.g., transmit receive points (TRPs) or sets of TRPs). In some scenarios, channel state information (CSI) feedback may take into account the CSI-reference signals (CSI-RSs) from multiple links. For example, CSI feedback may be based on CSI-RSs from multiple links if the antenna sub-arrays for the links are close to one another. As another example, a decision as to whether CSI feedback is to be based on CSI-RSs from multiple links may depend on channel conditions.

Abstract: Techniques are described for wireless communication. One method includes receiving, in a downlink portion of a transmission structure on a shared radio frequency spectrum band, an uplink grant for an uplink data portion of the transmission structure. The transmission structure includes the downlink portion, followed by and time domain multiplexed with an uplink control portion, followed by and time domain multiplexed with the uplink data portion. The method also includes retaining access to the shared radio frequency spectrum band by transmitting an unscheduled transmission during the uplink control portion of the transmission structure.

Abstract: Various aspects of the disclosure relate to controlling allocations for independent links. For example, a device may dynamically control the uplink/downlink allocations for different links. In some aspects, the independent links may involve a first device (e.g., a user equipment) communicating via different independent links with different devices (e.g., transmit receive points (TRPs) or sets of TRPs). At least one device may signal the uplink/downlink allocation for the different links. If the isolation between links is high, the links may use different time division duplexed (TDD) or frequency division duplexed (FDD) subframe structures. If the isolation is low or for certain types of information (e.g., control information), the direction of transmission for one link may be constrained to be the same as the direction of transmission for another link (e.g., the links may use the same TDD/FDD frame structures). Also, sounding on different links may be time division multiplexed.

Abstract: Channel state information (CSI) request procedures are disclosed for use in long term evolution (LTE)/LTE-Advanced (LTE-A) networks with unlicensed spectrum. Instead of relying on periodic reference signals which may not be transmitted because of failed clear channel assessment (CCA) operations, an aperiodic reference signal is defined that provides an on-demand reference signal and CSI request for user equipment (UE). The serving base station transmits an identifier, which signals that the aperiodic reference signal will be transmitted, either in the same subframe or a future subframe, and then transmits the aperiodic reference signal in the designated subframe. UEs served by the base station will receive the identifier, identify a CSI request, either implicitly through the identifier signal received from the base station or explicitly through a UE-specific CSI request, and then generate a CSI report based on the aperiodic reference signal for transmission back to the serving base station.

Abstract: Techniques for performing network-assisted peer discovery to enable peer-to-peer (P2P) communication are described. In one design, a device registers with a network entity (e.g., a directory agent) so that the presence of the device and possibly other information about the device can be made known to the network entity. The network entity collects similar information from other devices. The device sends a request to the network entity, e.g., during or after registration. The request includes information used to match the device with other devices, e.g., information about service(s) provided by the device and/or service(s) requested by the device. The directory agent matches requests received from all devices, determines a match between the device and at least one other device, and sends a notification to perform peer discovery. The device performs peer discovery in response to receiving the notification from the network entity.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) or base station communicating in an unlicensed radio frequency spectrum band may transmit a signal (e.g., a request-to-send (RTS) or clear-to-send (CTS) signal) in a licensed radio frequency spectrum band to decrease the likelihood that neighboring devices will transmit interfering communications. Specific resources may be designated in the licensed radio frequency spectrum band for transmitting these signals, and these resources may be associated with specific unlicensed channels. Signaling in the licensed radio frequency spectrum band may also carry an indication of the unlicensed channel being used or other information relevant to the unlicensed communication. The RTS/CTS signaling in licensed radio frequency spectrum band may be transmitted during a downlink transmit opportunity or an uplink transmit opportunity, or both.

Abstract: Methods, systems, and devices for wireless communication are described that provide for detection and management of hidden node interference. A user equipment (UE) may provide measurement reports to a serving transmitting device to help identify the hidden node interferer in response to detecting hidden node interference. The serving transmitting device may collaborate with one or more neighboring transmitting devices, such as other transmitting devices of an operator of a wireless communications system, to identify one or more of the neighboring transmitting devices that are within an energy detect or preamble detect radius of the hidden node. The serving transmitting device may coordinate with the neighboring transmitting device(s) to determine when the hidden node may transmit, to transmit coordinated preamble transmissions to prevent the hidden node from transmitting during a transmission, or to identify a modulation and coding scheme for the transmission.