Abstract: Certain aspects of the present disclosure relate to techniques for estimating a channel using soft-windowing. A user equipment (UE) may determine, based on a cyclic prefix (CP) length of a channel, a timing window for sampling reference signals transmitted on the channel, determine a set of weights to apply to samples obtained within the determined timing window, wherein each weight corresponds to a sample obtained within the determined window, and estimate the channel by applying the weights to the samples.

Abstract: Methods, systems, and devices for wireless communications are described. One method may include a user equipment (UE) determining whether it is configured to support a modulation scheme such as, a quadrature-amplitude-modulation (QAM). The UE may identify a plurality of transport block size (TBS) values based on whether the UE is configured with the modulation scheme, and identify a scaled TBS value that is based on a length of a transmission time interval (TTI). The UE may map the scaled TBS value to a TBS value of a plurality of TBS values (e.g., a plurality of TBS value options). As such, the UE may communicate, with a base station during the TTI, data on a transport block having a size corresponding to the mapped TBS value.

Abstract: The present disclosure relates to reducing control overhead in a wireless communication system. For example, a network entity may determine to transmit data according to a codeword format based on at least one of a transmission time interval (TTI), or a traffic type of the data, or any combination thereof, and configure the data for transmission on a communication channel according to the codeword format. Further, for instance, a user equipment may receive a transmission from a network entity on a downlink communication channel according to a codeword format, and transmit at least one of an acknowledgement (ACK) or a negative acknowledgement (NACK) on an uplink communication channel in response to receiving the transmission from the network entity.

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 communications are described. In some wireless communications systems, a user equipment (UE) may be configured to transmit hybrid automatic repeat request (HARQ) feedback for a set of codewords received from a base station in a single uplink channel. In some cases, it may be appropriate for the UE to transmit individual HARQ feedback for each codeword of the set of codewords (e.g., such that the UE may be able to transmit HARQ feedback for unscheduled transmissions to provide side information to the base station), and, in other cases, it may be appropriate for the UE to transmit bundled HARQ feedback for the set of codewords. Using the techniques described herein, the base station may configure the UE to provide individual HARQ feedback or bundled HARQ feedback for a set of codewords based on one or more factors.

Abstract: A method for wireless communication is disclosed which includes selecting a first resource pattern comprising resource elements that are non-colocated with a second resource pattern and allocating the first resource pattern to a plurality of antennas for transmitting a channel state information reference signal.

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: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a wireless communication device may identify that a last resource block of a resource allocation for a physical downlink shared channel (PDSCH) is in a last allocable resource block group (RBG); and determine whether one or more additional resource blocks, subsequent to the last resource block, are included in the resource allocation for the PDSCH based at least in part on at least one of a reference signal type associated with the PDSCH, a quantity of the one or more additional resource blocks, or the DCI format associated with the PDSCH. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A wireless device such as a user equipment (UE) may receive a first downlink shared channel transmission over a first set of frequency resources in a first transmission time interval (TTI); receive a downlink control transmission including a grant of a second set of frequency resources of a second TTI for a second downlink shared channel transmission, the downlink control transmission including an indication that a demodulation reference signal of the first downlink shared channel transmission is reused for the second downlink shared channel transmission; determine to rate match the second downlink shared channel transmission around resources of the second set of frequency resources that are not part of the first set of frequency resources, and receive the second downlink shared channel transmission over a subset of the second set of frequency resources.

Abstract: Methods, systems, and devices for wireless communications are described. In some wireless communications systems, a base station may configure a user equipment (UE) to transmit a first message in a set of transmission time intervals (TTIs) of a repetition window, and the base station may configure the same UE or a different UE to transmit a second message in a shortened TTI (sTTI). In such systems, if the base station schedules the transmission of the second message in an sTTI that coincides with at least one overlapping TTI in the set of TTIs of the repetition window, the UE may drop at least a portion of the transmission of the first message in the set of TTIs. Alternatively, the base station may avoid scheduling the uplink transmission of the second message in an sTTI that coincides with a TTI in the set of TTIs of the repetition window.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to communicate with a base station on different channels or messages with different processing timelines. In order to prevent a collision between processing communications associated with the different length TTIs, the UE may drop one or more communications on corresponding channels with longer processing timelines to receive and/or process the transmission on the channel with a shorter processing timeline. Additionally, the UE may transmit uplink control information (UCI) for the one or more dropped communications, where the UCI may include hybrid access request (HARQ) acknowledgement/negative acknowledgement (ACK/NAK) feedback, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), etc. If a downlink transmission is dropped, the UE may transmit a NAK message. Alternatively, if an uplink transmission is dropped, the UE may transmit at least a portion of the UCI.

Abstract: Systems, apparatuses, and methods for computing transport block size (TB S) for channels with shortened transmission time interval (sTTI). An initial size may be determined based on one or more TBS tables. The initial size may be scaled by a factor associated with an sTTI channel. A TBS table is selected based on the one or more TBS tables. The scaled size may be rounded based on the selected TBS table to generate a TBS for the sTTI channel.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine a capability of the UE relating to a carrier configuration of the UE, wherein the carrier configuration relates to carriers of at least two different numerologies; and transmit information identifying the capability, wherein the information identifying the capability identifies a bandwidth or number of carriers that is supported for carriers of a first numerology and one or more scaling values associated with one or more numerologies other than the first numerology. A base station may receive information identifying a capability of a UE relating to a carrier configuration of the UE, wherein the carrier configuration relates to carriers of at least two different numerologies; and determine a configuration for communication with the UE based at least in part on the information identifying the capability. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may identify that a scheduling request (SR) is to be transmitted on a first uplink control channel having a first transmission time interval (TTI) duration and identify that acknowledgment/negative acknowledgment (ACK/NACK) information is scheduled for transmission on a second uplink control channel having a second TTI duration greater than the first TTI duration, where the first uplink control channel and the second uplink control channel overlap in time. The UE may determine that the ACK/NACK information is to be transmitted with the SR on the first uplink control channel based on the overlapping first uplink control channel and second uplink control channel, and may determine resources of the first uplink control channel to be used for transmission of SR and ACK/NACK information. The UE may transmit the SR and the ACK/NACK information on the determined resources.

Abstract: Methods, systems, and devices for wireless communications are described. One method may include a user equipment (UE) determining a capability of the UE for at least one modulation order associated with a first transmission time interval (TTI) and a second TTI that is shorter than the first TTI, transmitting a UE capability message based on determining the UE capability, receiving a message including a parameter and a modulation coding scheme (MCS) index based on the UE capability message, and selecting a modulation table for communicating, to a base station, a transmission associated with the first TTI and the second TTI.

Abstract: Methods, systems, and devices for wireless communications are described. A base station may transmit control information to a UE in a shortened physical downlink control channel (sPDCCH). The sPDCCH may be included in shortened resource element groups (sREGs) of shortened channel control elements (sCCEs), which may be indexed in resource block (RB) sets by using localized or distributed mapping schemes. Updated sREG mapping schemes may result in a uniform distribution of sREGs within available symbols (and, as a result, a uniform distribution of unused resource blocks within the available symbols) and may ensure that sREGs within an sCCE are indexed into only one symbol.

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 communications are described. In some wireless communications systems, devices may implement carrier aggregation and shortened transmission time intervals (sTTIs) for downlink transmissions. To improve downlink throughput with a reduced feedback latency, the system may implement a modified hybrid automatic repeat request (HARQ) timeline. For example, a base station may configure a first component carrier with a TTI or sTTI for downlink that is longer than an sTTI for a second uplink component carrier. The base station and a user equipment (UE) may operate using a HARQ timing for the first component carrier that is based on the shorter sTTI for the second component carrier. The base station may transmit a downlink transmission using the longer TTI or sTTI for greater carrier aggregation, and the UE may send a downlink HARQ acknowledgment (ACK) message in response according to the HARQ timing for reduced latency.

Abstract: A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus may identify a potential collision between a scheduled legacy transmission time interval (TTI) communication and a scheduled shortened TTI (sTTI) communication, the legacy TTI communication having a legacy TTI duration that is longer than an sTTI duration associated with the sTTI communication. The apparatus may determine whether the legacy TTI communication is within a threshold time of being transmitted. The apparatus may transmit at least one of the sTTI communication, the legacy TTI communication, or any combination thereof, based at least in part on the determination.

Abstract: Methods, systems, and devices for prioritization of channel state information (CSI) processes based on a set of priority rules and a device capability are described. A user equipment (UE) may be capable of supporting multiple communication types such as ultra-reliable low latency communications (URLLC), shortened transmission time interval (sTTI), enhanced mobile broadband (eMBB) priority type, etc. The UE may indicate a CSI update capability that includes a number of CSI processes capable of being updated by the UE. The CSI update capability may be a joint CSI update capability provided for all communication types. Based on the CSI update capability of the UE and the set of priority rules, the UE may prioritize the updating of one or more CSI processes.