Abstract: Various aspects described herein relate to scheduling resources in wireless communications. In one aspect, communications can be established with a plurality of user equipment (UE). A set of the plurality of UEs as having an interference impact on one another that is less than a threshold can be determined. A first UE of the set of the plurality of UEs can be scheduled for downlink communications in a first transmission time interval (TTI), and a second UE of the set of the plurality of UEs can be scheduled for uplink communications in a second TTI that is adjacent in time to the first TTI. In another aspect, uplink communications for the first UE can be scheduled in a portion of the guard period TTI based at least in part on determining a timing advance of the first UE is less than a threshold.

Abstract: Various aspects described herein relate to communicating using a configurable bandwidth. A user equipment (UE) can receive a control channel from a serving evolved Node B (eNB), where the control channel includes a resource grant for an uplink shared data channel including a number of resource block groups starting from a starting resource block group in an allocation space, and where the allocation space includes a plurality of resource block groups in a frequency domain over a plurality of symbols in a time domain. The UE can transmit data in the uplink shared data channel starting from the starting resource block group in the allocation space and continuing through the number of resource block groups in the allocation space over the frequency domain first and over the time domain second.

Abstract: Certain aspects of the present disclosure provide methods for wireless communications by a base station and a user equipment in a network. An exemplary method generally includes performing a discovery procedure to identify one or more devices through which the UE may indirectly communicate with a base station in the network and deciding based on one or more criteria whether to communicate with the base station directly or to communicate with the base station indirectly via a device identified by the discovery procedure. According to certain aspects, when a UE is in communication with a network indirectly, the network might page the UE directly, indirectly, or both.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless device such as a user equipment (UE) or a base station may identify a set of resource element groups (REGs) for low latency communication, and each REG may include a portion of a different resource block (RB) of a set of RBs (e.g., a set of non-contiguous RBs). The device may then map an uplink control channel to the selected REGs and communicate on the uplink control channel accordingly. Reference signals may also be transmitted in the same RBs, and the REGs may be mapped around the resources used for reference signals. In some cases, multiple UEs may transmit uplink control data using the same resources using code division multiplexing (CDM) (e.g., if the control payload is relatively small). In other cases, multiple UEs may be frequency division multiplexed (FDM).

Abstract: Methods, systems, and devices for wireless communication are described. A wireless device may identify an uplink/downlink (UL/DL) configuration that defines subframe configuration options for each subframe of a frame. For example, the UL/DL configuration may establish parameters for time division duplexing (TDD) operation between a base station and a user equipment (UE). The wireless device (e.g., the UE or base station) may determine a constraint for a subframe of the frame based on the UL/DL configuration and then determine an adaptive subframe configuration based on the constraint. The adaptive subframe configuration may include one or several downlink symbol periods and one or several uplink symbol periods.

Abstract: Various techniques for narrowband communications in a wireless communications network are provided. Narrowband communications may be transmitted using a single resource block (RB) of a number of RBs used for wideband communications. In order to provide for efficient device discovery and synchronization using narrowband communications, a synchronization signal, such as a primary synchronization signal (PSS) or secondary synchronization signal (SSS), may be transmitted within the single resource block. The synchronization signal may be transmitted, for example, using multiple orthogonal frequency division multiplexing (OFDM) symbols within the single RB. A common reference signal (CRS) may also be present in the single resource block, which may puncture the synchronization signal, in some examples. In other examples, the synchronization signal may be mapped to non-CRS symbols of the single resource block.

Abstract: Random access techniques may use subcarriers allocated for random access requests in narrowband communication. Physical resources may be selected for transmission of a random access request based on a “coverage class” of a user equipment (UE). In some examples, a set of coverage classes may be identified based on one or more UE channel conditions, such as pathloss. Each coverage class may have one or more associated subcarriers of a set of subcarriers in a narrowband bandwidth, and random access messages may be transmitted using the associated subcarrier(s) for the coverage class of a UE. In some examples, different coverage classes may have different numbers of redundant transmissions of a random access message, which may be based on channel conditions associated with a particular coverage class. A UE, based on a measured channel condition, may determine a coverage class and select a subcarrier based on the determined coverage class.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless device may receive a data transmission during a transmission time interval (TTI) that has one duration, and the device may transmit a responsive control message (e.g., acknowledgment information) in a subsequent TTI that has a different duration (e.g., a greater duration). In some cases, the control message may include bundled acknowledgment information for multiple downlink transmissions. The control message may, for instance, include acknowledgment information for data received during several TTIs having one duration bundled with acknowledgment information for data received during TTIs that have a different duration. The acknowledgment information may be compressed using, for example, a starting point and run length of consecutive negative acknowledgments.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless device may identify multiple regions within a subframe, such as one or more uplink regions, one or more downlink regions, and a guard region. The wireless device may identify and communicate during each region based on a timing relationship between the downlink region and the uplink region. For example, the device may expect hybrid automated repeat request (HARQ) feedback for one downlink region in the same subframe based on the proximity to the next uplink region. Another downlink region may not have HARQ feedback in the same subframe. Similarly, uplink regions may or may not be scheduled within the same subframe.

Abstract: Certain aspects of the present disclosure provide techniques for controlling transmission power in shared radio frequency spectrum (SRFS). According to techniques, devices (e.g., BSs, UEs, etc.) transmitting in SRFS band may win contention to the SRFS band for at least a portion of a radio frame period. For example, the radio frame period may include a plurality of subframe periods. The devices may also transmit a first signal at a first transmit power during a first subframe period of the radio frame period and transmit a second signal at a second transmit power during a second subframe period of the radio frame period. For example, the first transmit power and second transmit power may be controlled based, at least in part, on a power level determined for the radio frame period.

Abstract: An apparatus includes a memory and a circuit. The memory may have a transmitter. The memory may be configured to (a) train transmit parameters of the transmitter that synchronize transmission of data with a clock signal while in a first mode, (b) save the transmit parameters in response to a command received while in the first mode, and (c) transmit additional data while in a second mode using the transmit parameters learned while in the first mode. The circuit may have a receiver in communication with the memory. The circuit may be configured to (a) train receive parameters of the receiver that synchronize reception of the data with the clock signal while the memory is in the first mode and (b) receive the additional data from the memory while the memory is in the second mode using the receive parameters learned while the memory was in the first mode.

Abstract: Methods, systems, and devices for wireless communication using various patterns of data and reference signals are described. For example, in a system that supports operation using different duration transmission time intervals (TTIs), a base station may initiate communication with a user equipment (UE) or between two UEs, and UEs may communicate with the base station or with one another using an indicated pattern of data and reference signals. The base station may send a downlink control message indicating a transmission pattern selected from a set of patterns. UEs may identify the pattern based on the indicator and decode a sequence of data and reference signals based on the pattern. In some examples, the sequence may include a set of TTIs, which may have a shorter duration than other TTIs.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) and a base station may use low latency communications to improve the throughput of a wireless link. To facilitate efficient low latency communication, the UE may send UE-initiated CSI reports in addition to periodic and base station-initiated reports. For example, the UE may, in various examples, send UE-initiated CSI reports using contention based spectrum, using a request-to-transmit, or using a CSI differential (i.e., an indicator of a change in channel conditions). The base station may schedule different UEs for uplink low latency communication by providing resources to each UE for CSI and scheduling requests (SRs) using coherent or non-coherent uplink transmissions. The CSI and SR may also be combined with uplink feedback.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may operate in a system that supports operation with transmission time intervals (TTIs) of different durations. The UE may monitor for a grant during a first TTI and may determine the communication direction of a second TTI based on a received grant. The UE may re-determine the communication direction of the second TTI based, for example, on an explicit indication. In some examples, the UE may adapt uplink scheduling timing based on the indicator. In some examples, a UE may communicate in one direction during a TTI of a first duration and may communicate in a different direction during a TTI of the second duration that is within the TTI of the first duration.

Abstract: The present disclosure, for example, relates to one or more techniques for indicating a frame format for transmissions using unlicensed radio frequency spectrum bands. A UE may receive, from a base station, a frame format indicator associated with a transmission opportunity for transmissions in an unlicensed radio frequency spectrum band. The UE may determine a time-division duplexing (TDD) configuration for the transmission opportunity based at least in part on the frame format indicator.

Abstract: Various aspects described herein relate to receiving data at a user equipment (UE) in wireless communications. The UE monitors a control channel associated with first data resources of a first transmission time interval (TTI). Based on the monitoring, the UE can determine that the control channel schedules second data resources for the UE based on a second TTI. Accordingly, in response to such determination, the UE can process data received over the second data resources based on the second TTI, where a first duration of the first TTI is greater than a second duration of the second TTI.

Abstract: Methods, systems, and devices for wireless communication are described. A base station may select, and a user equipment (UE) may identify, an initial symbol of a transmission time interval (TTI) based on a particular characteristic of a communication link between the base station and UE. A two-symbol TTI for one UE may thus be scheduled to align with or complement a longer TTI for another UE. For instance, the initial symbol of a two-symbol TTI may be restricted to certain symbol periods of a Long Term Evolution (LTE) subframe to limit interference with other transmissions scheduled during the subframe (e.g., reference signals, control channels, guard periods, etc.). Additionally or alternatively, a UE may identify and blindly decode control channel transmissions for low latency communications by assuming a presence of reference signals within the symbols that include a low latency control channel.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may receive a downlink transmission from a base station, transmit a first stage of feedback for the downlink transmission, identify a condition associated with the downlink transmission, and determine whether to transmit a second stage of feedback for the downlink transmission based at least in part on the identified condition associated with the downlink transmission. The second stage of feedback for the downlink transmission may be transmitted (or not transmitted) based at least in part on the identified condition associated with the downlink transmission.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) or a base station may identify a timing advance parameter and a processing parameter for the UE, and one or both may determine a hybrid automatic repeat request (HARQ) timing based on the identified parameters. For example, if the UE has a large timing advance or reduced processing capacity, a longer HARQ timing may be chosen. When the UE receives downlink (DL) transmissions from the base station, the UE may send an acknowledgement (ACK) or negative acknowledgement (NACK) based on the chosen HARQ timing. The base station may send a retransmission (in the case of a NACK) based on the HARQ timing. In some cases, the UE may request a specific HARQ timing, or request an updated timing advance. If HARQ synchronization is lost, the UE and the base station may default to a preconfigured HARQ timing.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may determine separate uplink (UL) power limitations for multiple transmission time interval (TTI) durations based on distinct power control parameters. In some cases, an adjustment factor or a power backoff may be applied to communications using one TTI duration to ensure that total transmit power does not exceed a threshold. The UE and the serving base station may also identify one or more demodulation reference signal (DMRS) windows. UL data transmissions may be demodulated based on a DMRS sent during the same window. Transmit power control (TPC) commands may be applied at the beginning of each window. However, if an UL transmission is scheduled at the beginning of the window, the UE may wait until a DMRS transmission or until no more transmissions are scheduled for the window before applying the TPC adjustment.