Abstract:
Aspects of the present disclosure relate to wireless communications and, more particularly, to synchronization for standalone long term evolution (LTE) broadcast. In one aspect, a method is provided which may be performed by a wireless device such as a user equipment (UE). The method generally monitoring, within anchor subframes occurring at a first periodicity, for synchronization signals of a first type, obtaining an indication of one or more unicast subframes scheduled to occur between anchor subframes, and obtaining an indication of one or more broadcast subframes scheduled to occur between anchor subframes.
Abstract:
Uplink scheduling for license assisted access (LAA) mode systems is discussed in which a base station transmits a conditional grant to served user equipments (UEs) that include a transmission configuration for uplink transmissions. The transmission configuration includes the parameters necessary for the UE to perform transmissions. Before the beginning of a uplink transmission opportunity, a base station transmits an uplink activation grant over a contention-based shared carrier to the served UEs. The uplink activation grant indicates the transmission opportunity to the UEs and may identify a subset of UEs out of the served UEs that are available for transmission. The base station first secures the channel before transmitting the uplink activation grant. Upon receipt of the uplink activation grant, the UEs determine whether they will perform uplink transmissions and, if so, transmit the uplink data according to the transmission configuration.
Abstract:
Methods, systems, and devices for wireless communication are described. A wireless device configured for carrier aggregation may communicate using transport blocks (TBs) mapped according to a wideband configuration that includes resources of multiple component carriers (CCs) within a single, low latency transmission time interval (TTI)-e.g., a TTI that has a shorter duration relative to other TTIs used in the same system. The number of CCs, and thus bandwidth, available for mapping each TB may change dynamically based on the configuration of the CCs. For a CC configured with a control region during a given low latency TTI, a TB sent during that low latency TTI may not be mapped to resources of that CC. In other cases, portions of a CC configured with a control region may be used for wideband configurations. Wideband low latency communications may be used on the uplink or downlink communications, or both.
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. The wireless device may then communicate during the subframe according to the adaptive subframe configuration rather than the original UL/DL configuration; and, because the adaptive subframe may be constrained by the identified UL/DL configuration, the communication during the subframe may avoid disruption to UEs.
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:
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:
Techniques for uplink transmission management in a wireless communications system are described herein. An example method may include receiving an explicit uplink grant that indicates one or more implicit uplink grants. In an aspect, the example method may include performing a first clear channel assessment (CCA) in response to the explicit uplink grant in a first time slot. In another aspect, the example method may include, if the first CCA fails, sequentially performing one or more additional CCAs respectively in one or more time slots subsequent to the first time slot in response to the one or more implicit uplink grants, and transmitting the PDU over the unlicensed or shared spectrum and in a time slot subsequent to the time slot in which one of the one or more additional CCAs succeeds.
Abstract:
Enhanced discontinuous reception (DRX) techniques are discussed for networks configured with some combination of contention-based spectrum. Various aspects provide common or separate DRX configurations across all carriers and cells. Durations may be adjusted to increase the probability of a user equipment (UE) remaining active for the base station to secure the shared channel. Physical layer commands may also be transmitted for UE to enter sleep mode dynamically in order to further save power. Additional triggering signals sent via the physical layer or layer 1 signaling, such as fast wake-up signals or fast sleep signals, may either wake the UE for monitoring the contention-based spectrum of the secondary carrier or cause the UE to enter a sleep mode after monitoring is over. Further aspects provide to initiate DRX procedures in contention-based spectrum in response to detected CUBS or other channel usage signals.
Abstract:
According to the present disclosure, CSI and/or a plurality of ACKs related to a group of DL data transmissions may be buffered at the UE as a GACK until a DCI trigger is received from the eNB. Once the trigger is received, the UE may transmit the CSI and/or GACK to the eNB. In this way HARQ feedback and/or CSI may be reliably communicated while reducing payload. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus send, to a UE, data transmissions associated with a first plurality of downlink subframes. In an aspect, the apparatus increments a counter for each data transmission sent to the UE. In a further aspect, the apparatus transmits, to the UE, a first trigger for a first GACK when a counter is greater than or equal to a threshold.
Abstract:
In the present disclosure, CSI and/or a plurality of ACK/NACKs related to a group of DL data transmissions may be buffered at the UE as a GACK until a DCI trigger is received from the eNB. When the DCI trigger is received, the UE may transmit the CSI and/or GACK. In this way, HARQ feedback and/or CSI may be reliably communicated even if a CCA does not clear and/or UL subframes are unavailable. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. In an aspect, the apparatus may be a UE. The apparatus monitors one or more subframes for a DCI trigger. In a further aspect, the apparatus receives the DCI trigger in a subframe. In another aspect, the apparatus transmits UCI using a subsequent subframe.