Abstract: Methods, systems, and devices for wireless communication are described. Some wireless communications systems may support communication between a user equipment (UE) and a base station on multiple carriers (i.e., carrier aggregation). In some cases, the UE may be scheduled to transmit uplink signals on the different component carriers during transmission time intervals (TTIs) that have different durations. In such cases, it may be appropriate for the UE to determine a maximum transmit power limit relating to the amount of power used for the uplink transmissions on the multiple carriers. As described herein, the UE may identify one of the component carriers as a reference component carrier, and the UE may determine the maximum transmit power limit for a duration of a TTI associated with the reference component carrier. The UE may then transmit on the multiple carriers in compliance with the maximum transmit power limit.

Abstract: Certain aspects of the present disclosure relate to communication systems, and more particularly, to improving performance for sounding reference signal (SRS) antenna switching in carrier aggregation (CA). A method is provided, that may be performed by a user equipment (UE) for wireless communications. The method includes determining one or more band combinations that share an antenna switch and sending a list of one or more bands in the one or more band combinations to a base station (BS). The BS receives the list and schedules the UE based on the received list.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may group multiple carriers with transmission time intervals (TTIs) having different durations into different physical uplink control channel (PUCCH) groups. The UE may reserve power per each PUCCH group. Alternatively, the UE may reserve power per each TTI duration across the one or more PUCCH groups.

Abstract: Certain aspects of the present disclosure provide techniques for capability information for sounding reference signal (SRS) improvements. An exemplary method generally includes determining a capability of the UE related to additional sounding reference signal (SRS) transmissions in a normal uplink (UL) subframe; transmitting, to a base station (BS), capability information indicating the determined capability of the UE; receiving SRS configuration information, wherein the SRS configuration information is based, at least in part, on the capability information; and transmitting at least one SRS in accordance with the SRS configuration information.

Abstract: Methods, systems, and devices for wireless communication are described that support time mask techniques for shortened transmission time intervals (sTTIs) that may enhance low latency communications. Time masks may be identified and applied for transmissions that use sTTIs, in a manner that provides increased portions of sTTI durations having higher transmission power, and thus increase the likelihood of successful reception of such transmissions at a receiver. In some cases, a transmitter, such as a user equipment (UE), may identify one or more sTTIs for transmissions of a first wireless service (e.g., an ultra-reliable low-latency communication (URLLC) service). An sTTI may be identified based on a duration of a TTI associated with the first wireless service being below a threshold duration (e.g., a TTI duration of less than 1 ms may be identified as an sTTI).

Abstract: Certain aspects of the present disclosure provide techniques for handling collisions between PUSCH and sounding reference signal (SRS) on additional SRS symbols in an uplink subframe using carrier aggregation. The techniques provide rules that a user equipment (UE) may apply to decide if and when to drop or apply power scaling to SRS or PUSCH transmissions scheduled on overlapping time resources.

Abstract: Methods, systems, and devices for wireless communication are described that support dynamic transient period configurations for shortened transmission time intervals (sTTIs). A transient period may be configured within uplink transmissions such that protection is enabled for reference signals and data. For example, a user equipment (UE) may receive a resource grant from a base station for an uplink transmission, where the uplink transmission includes at least a first reference signal and a transmission time interval (TTI) that includes data and a second reference signal. The UE may identify a type of the reference signals and data, and may determine a priority based on the identified types of reference signals and data. The UE may then configure a transient period that overlaps with the first reference signal, the TTI, or both, based on the priority.

Abstract: Certain aspects of the present disclosure provide techniques for capability information for sounding reference signal (SRS) improvements. An exemplary method generally includes determining a capability of the UE related to additional sounding reference signal (SRS) transmissions in a normal uplink (UL) subframe; transmitting, to a base station (BS), capability information indicating the determined capability of the UE; receiving SRS configuration information, wherein the SRS configuration information is based, at least in part, on the capability information; and transmitting at least one SRS in accordance with the SRS configuration information.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may group multiple carriers with transmission time intervals (TTIs) having different durations into different physical uplink control channel (PUCCH) groups. The UE may reserve power per each PUCCH group. Alternatively, the UE may reserve power per each TTI duration across the one or more PUCCH groups.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may group multiple carriers with transmission time intervals (TTIs) having different durations into different physical uplink control channel (PUCCH) groups. The UE may reserve power per each PUCCH group. Alternatively, the UE may reserve power per each TTI duration across the one or more PUCCH groups.

Abstract: Certain aspects of the present disclosure provide techniques for handling collisions between PUSCH and sounding reference signal (SRS) on additional SRS symbols in an uplink subframe using carrier aggregation. The techniques provide rules that a user equipment (UE) may apply to decide if and when to drop or apply power scaling to SRS or PUSCH transmissions scheduled on overlapping time resources.

Abstract: Methods, systems, and devices for wireless communication are described. Multiple transmission time intervals (TTIs) may be used for communications between a base station and user equipment (UE), where each TTI may have a data pattern scheduled by a base station. Each TTI may include respective symbol periods designated as reference or data symbol periods. In some examples, the UE may be configured to transmit a sounding reference signal (SRS) in a last symbol period of a TTI, and a base station may dynamically determine a data pattern for the TTI such that a temporally last symbol period is immediately preceded by a reference symbol period (e.g., based on the presence of the SRS). In such cases, the UE may configure a transient time within the preceding reference symbol period to avoid signal degradation of the SRS (or data transmitted within the same TTI).

Abstract: Some aspects described herein reduce the negative performance impact associated with the voltage droop of a user equipment (UE) battery. For example, aspects described herein may be used to configure a UE with a pattern that includes a battery recovery time period that prevents a battery voltage of the UE from falling below a critical threshold and/or reduces the likelihood of the battery voltage falling below the critical threshold. In this way, UE performance may be improved, battery performance may be improved, battery life may be extended, and/or the like.

Abstract: Methods, systems, and devices for wireless communication are described that support time mask techniques for shortened transmission time intervals (sTTIs) that may enhance low latency communications. Time masks may be identified and applied for transmissions that use sTTIs, in a manner that provides increased portions of sTTI durations having higher transmission power, and thus increase the likelihood of successful reception of such transmissions at a receiver. In some cases, a transmitter, such as a user equipment (UE), may identify one or more sTTIs for transmissions of a first wireless service (e.g., an ultra-reliable low-latency communication (URLLC) service). An sTTI may be identified based on a duration of a TTI associated with the first wireless service being below a threshold duration (e.g., a TTI duration of less than 1 ms may be identified as an sTTI).

Abstract: Methods, systems, and devices for wireless communication are described. In some cases, a user equipment (UE) may be scheduled to transmit uplink signals on different carriers during transmission time intervals (TTIs) that have different durations. As such, a TTI on a first carrier (e.g., a reference carrier) may overlap with multiple shortened TTIs (sTTIs) on a second carrier (e.g., a non-reference carrier). Using the techniques described herein, the UE may select a calibration point (or a gain index) for uplink transmissions at the beginning of the TTI on the reference carrier based on an amount of power reserved for expected power increases during the TTI. As such, when the UE has to update its transmit power for an uplink transmission during an sTTI on the second carrier, the UE may apply a digital back-off from a power associated with the calibration point.

Abstract: Methods, systems, and devices for wireless communication are described that support time mask techniques for shortened transmission time intervals (sTTIs) that may enhance low latency communications. Time masks may be identified and applied for transmissions that use sTTIs, in a manner that provides increased portions of sTTI durations having higher transmission power, and thus increase the likelihood of successful reception of such transmissions at a receiver. In some cases, a transmitter, such as a user equipment (UE), may identify one or more sTTIs for transmissions of a first wireless service (e.g., an ultra-reliable low-latency communication (URLLC) service). An sTTI may be identified based on a duration of a TTI associated with the first wireless service being below a threshold duration (e.g., a TTI duration of less than 1 ms may be identified as an sTTI).

Abstract: Certain aspects of the present disclosure relate to communication systems, and more particularly, to improving performance for sounding reference signal (SRS) antenna switching in carrier aggregation (CA). A method is provided, that may be performed by a user equipment (UE) for wireless communications. The method includes determining one or more band combinations that share an antenna switch and sending a list of one or more bands in the one or more band combinations to a base station (BS). The BS receives the list and schedules the UE based on the received list.

Abstract: Methods, systems, and devices for wireless communication are described. Multiple transmission time intervals (TTIs) may be used for communications between a base station and user equipment (UE), where each TTI may have a data pattern scheduled by a base station. Each TTI may include respective symbol periods designated as reference or data symbol periods. In some examples, the UE may be configured to transmit a sounding reference signal (SRS) in a last symbol period of a TTI, and a base station may dynamically determine a data pattern for the TTI such that a temporally last symbol period is immediately preceded by a reference symbol period (e.g., based on the presence of the SRS). In such cases, the UE may configure a transient time within the preceding reference symbol period to avoid signal degradation of the SRS (or data transmitted within the same TTI).

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may group multiple carriers with transmission time intervals (TTIs) having different durations into different physical uplink control channel (PUCCH) groups. The UE may reserve power per each PUCCH group. Alternatively, the UE may reserve power per each TTI duration across the one or more PUCCH groups.

Abstract: Methods, systems, and devices for wireless communication are described. In some cases, a user equipment (UE) may be scheduled to transmit uplink signals on different carriers during transmission time intervals (TTIs) that have different durations. As such, a TTI on a first carrier (e.g., a reference carrier) may overlap with multiple shortened TTIs (sTTIs) on a second carrier (e.g., a non-reference carrier). Using the techniques described herein, the UE may select a calibration point (or a gain index) for uplink transmissions at the beginning of the TTI on the reference carrier based on an amount of power reserved for expected power increases during the TTI. As such, when the UE has to update its transmit power for an uplink transmission during an sTTI on the second carrier, the UE may apply a digital back-off from a power associated with the calibration point.