Abstract: Methods, systems, and devices for wireless communications are described. The described techniques provide for a user equipment (UE) using information identified via radio access technology (RAT) (e.g., Long Term Evolution (LTE)) to support communications in another RAT (e.g., New Radio (NR)). For example, the UE may receive, from a first base station operating according to a first radio access technology an indication of a high speed associated with a first wireless connection of the UE with the first base station. The UE may perform a channel estimation procedure for the first wireless connection to generate a Doppler value based on receiving the indication. The UE may apply the generated Doppler value to a frequency tracking loop or a time tracking loop for communications with a second base station via a second wireless connection, wherein the second base station is operating according to a second RAT.

Abstract: Methods, systems, and devices for wireless communications are described. Generally, a user equipment (UE) may communicate with a first network device in a first communications system (e.g., a non-standalone (NSA) system) prior to initiating a handover to a second communications system (e.g., a standalone (SA) system). In some examples, the UE may receive a first tracking reference signal (TRS) from the first network device using a first transmission configuration indicator (TCI) state. The first network device may include an indication of the first TCI state in a control message. The UE may initiate a handover from the first network device to the second network device. Subsequent to the handover, the UE may receive a second TRS from the second network device. The UE may receive the second TRS using the first TCI state based on determining that one or more antenna port configuration conditions are satisfied.

Abstract: A device may selectively listen for a tracking reference signal (TRS) during connected mode discontinuous reception (CDRx) based on whether the device is to switch between repeaters of a base station (such as during travel). A device may determine whether the device is in a high speed train (HST) scenario (such as based on a difference in frequency errors generated using a synchronization signal block (SSB) and generated using a TRS, based on a trajectory of a frequency error or a frequency error difference over time, based on instantaneous frequency errors, etc.). When the device is in a HST scenario, the device listens for a TRS during CDRx, and the device generates a frequency error using the TRS. When the device is not in a HST scenario, the device prevents listening for a TRS during CDRx (with a SSB received during CDRx to be used to generate a frequency error).

Abstract: Methods, systems, and devices for wireless communications are described that provide for receive chain selection at a user equipment (UE) with efficient switching between a reduced number of receive chains and an increased number of receive chains for downlink communications based on conditions at the UE. A UE may adaptively adjust the number of active receive chains based on downlink grant activity, channel conditions, network parameters, or any combinations thereof. An estimator block at the UE may determine to adjust the number of receive chains based on a number of downlink grants within one or more time periods. In some cases, grants for an amount of data that exceeds a threshold may be qualified in order to be counted at the estimation block. Further, a transient state may be provided where the UE may maintain a higher number of active receive chains until UE feedback is provided.

Abstract: Methods, systems, and devices for wireless communications are described in which a user equipment (UE) may perform beam measurements for one or more subsets of beams that are selected to provide enhanced beam switch determinations. The UE may identify one or more prioritized beams, and may measure the prioritized beams at a same periodicity as measurements of a serving beam. The UE may, additionally or alternatively, identify a set of all layer one beams (e.g., maximum-level beams or top level beams) for measurement according to a periodic interval, based on a measured mobility being less than a threshold value. The periodic interval may provide that each layer one beam may be measured at a cadence of one beam per measurement occasion, in order to provide measurement diversity.

Abstract: A device may selectively listen for a tracking reference signal (TRS) during connected mode discontinuous reception (CDRx) based on whether the device is to switch between repeaters of a base station (such as during travel). A device may determine whether the device is in a high speed train (HST) scenario (such as based on a difference in frequency errors generated using a synchronization signal block (SSB) and generated using a TRS, based on a trajectory of a frequency error or a frequency error difference over time, based on instantaneous frequency errors, etc.). When the device is in a HST scenario, the device listens for a TRS during CDRx, and the device generates a frequency error using the TRS. When the device is not in a HST scenario, the device prevents listening for a TRS during CDRx (with a SSB received during CDRx to be used to generate a frequency error).

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify a set of base stations that are part of a synchronization group, where at least two of the base stations in the set of base stations operate on different frequencies. In some cases, the UE may identify the set of base stations based on an indication transmitted by a serving base station for the UE. Additionally, once the synchronization group is identified, the UE may schedule synchronization signals together from the set of base stations. For example, after identifying the set of base stations, the UE may identify a measurement timing window associated with the synchronization group and measure a respective synchronization signal for each base station within the measurement timing window. Accordingly, the UE may then transmit a measurement report to the serving base station that includes the synchronization signal measurements.

Abstract: A cell acquisition technique for 5G and other RATs is provided in which shallow scans are interleaved with deep scans. In each shallow scan, a UE determines whether a synchronization signal is received with sufficient signal quality over one period for the synchronization signal. In each deep scan, the UE determines whether the synchronization signal is received with sufficient signal quality over multiple periods for the synchronization signal.

Abstract: Techniques are described herein that allow a user equipment (UE) to configure a subcarrier spacing value while monitoring synchronization signals of neighboring cells. In some wireless communication systems, synchronization signals in given radio frequency spectrum band may be transmitted using one of a plurality of different subcarrier spacings. In some cases, a network entity, such as a base station, may transmit an indication to the UE that indicates the subcarrier spacing used by a cell to transmit a specific set of synchronization signals. In some cases, the UE may select a subcarrier spacing based on a database of subcarrier spacings stored locally by the UE. In some cases, the UE may select the subcarrier spacing based on a predetermined configuration.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify a set of base stations that are part of a synchronization group, where at least two of the base stations in the set of base stations operate on different frequencies. In some cases, the UE may identify the set of base stations based on an indication transmitted by a serving base station for the UE. Additionally, once the synchronization group is identified, the UE may schedule synchronization signals together from the set of base stations. For example, after identifying the set of base stations, the UE may identify a measurement timing window associated with the synchronization group and measure a respective synchronization signal for each base station within the measurement timing window. Accordingly, the UE may then transmit a measurement report to the serving base station that includes the synchronization signal measurements.