Abstract: Techniques are described for wireless communication. A first method includes winning a contention for access to an unlicensed radio frequency spectrum band, and transmitting at least a portion of a channel usage beacon signal (CUBS) over the unlicensed radio frequency spectrum band. The at least portion of the CUBS is transmitted in a number of frequency interlaces of the unlicensed radio frequency spectrum band. A second method includes winning a contention for access to an unlicensed radio frequency spectrum band; determining whether the contention is won within a threshold time before a next symbol period boundary; and transmitting at least a portion of a CUBS over the unlicensed radio frequency spectrum band. The at least portion of the CUBS is transmitted during a preamble including a fractional period of a first symbol period. The at least portion of the CUBS may be based at least in part on the determining.

Abstract: A base station may configure a set of autonomous uplink (AUL) resources for a specific base station receive beam, or the AUL resources may be configured for specific user equipment (UEs) or user groups. Additionally, the AUL resources may be configured to include a sensing portion, a data portion, or both. As an example, a UE may receive an AUL configuration that includes an indication of a set of AUL resources that are specific to a base station receive beam. The UE may then determine that the set of AUL resources is available and perform an AUL transmission of uplink data using the set of beam-specific AUL resources. Additionally or alternatively, the UE may perform the AUL transmission with respective portions that include a sensing signal and the uplink data. The base station may use the sensing signal to determine a receive beam on which to receive the uplink data.

Abstract: Aspects of the present disclosure provide techniques for design of synchronization signals for narrowband operation and other clean-slate, OFDM based systems such as enhanced component carrier (eCC) systems. An example method is provided for operations which may be performed by a BS to generate and transmit a dual-layer PSS, and correspondingly, techniques for a UE to detect the dual-layer PSS. The PSS may be generated utilizing a binary code cover and at least one sequence applied to a number of symbols within one or more subframes of a frame.

Abstract: Aspects of the present disclosure provide techniques for uplink (UL) data channel design. An example method is provided for operations which may be performed by a first apparatus. The example method generally comprises determining a number of pilot symbols to transmit for one or more slots of a first subframe based, at least in part, on a coverage enhancement (CE) level, and transmitting at least one uplink data channel having the determined number of pilot symbols in the one or more slots of the first subframe.

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 base station (BS). The method generally includes providing unicast coverage to one or more user equipments (UEs) in a unicast coverage area within a larger coverage area, transmitting unicast data in one or more subframes, and transmitting synchronization signals within one or more of the broadcast subframes, wherein the broadcast signals are transmitted as single frequency network (SFN) transmissions synchronized with transmissions from one or more other base stations providing unicast coverage within the larger coverage area.

Abstract: Wireless communications systems and methods related to performing adaptive autonomous uplink (UL) communications are provided. A first wireless communication device receives, from a second wireless communication device, an autonomous uplink transmission configuration. The first wireless communication device determines a transmission parameter in response to a link adaptation parameter based on the autonomous uplink transmission configuration. The first wireless communication device transmits, to the second wireless communication device, an autonomous uplink communication signal based on the determined transmission parameter.

Abstract: Long term evolution (LTE)/LTE-Advanced (LTE-A) deployments with unlicensed spectrum leverage more efficient LTE communication aspects over unlicensed spectrum, such as over WIFI radio access technology. In order to accommodate such communications, various downlink procedures may be modified in order to handle communications between licensed and unlicensed spectrum with LTE/LTE-A deployments with unlicensed spectrum.

Abstract: Techniques for wireless communications over a shared radio frequency spectrum band, may include techniques for transmitting uplink data transmissions using allocated uplink resources. Allocated uplink resources may include an uplink channel comprising a number of allocated interlaces of resource blocks (RBs) for use by a user equipment (UE). An incoming data stream may be processed and data separated into each of the allocated interlaces of RBs for the UE. Such separation may be through demultiplexing the data stream to obtain data for the allocated interlaces of RBs. The demultiplexed data may be mapped onto associated resource elements associated with the allocated interlaces of RBs, and transmitted. Different types of uplink channels, such as a physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH) and/or a physical random access channel (PRACH) may be allocated to interlaces of RBs in one or more subframes of a transmitted radio frame.

Abstract: Techniques are described for wireless communication. A first method may include inserting, in a first transmission using a first radio access technology (RAT), a channel occupancy identifier for a second transmission using a second RAT. The first method may also include transmitting the first transmission having the channel occupancy identifier over an unlicensed radio frequency spectrum band. A second method may include receiving, at a receiver operated using a first RAT, a channel occupancy identifier for a transmission using a second RAT. The channel occupancy identifier may be received over an unlicensed radio frequency spectrum band. The second method may also include decoding the channel occupancy identifier to identify a backoff period, and refraining from accessing the unlicensed radio frequency spectrum band using the first RAT based at least in part on the identified backoff period.

Abstract: Systems, methods, and apparatuses are described for wireless communication, including for hybrid automatic repeat request (HARQ) feedback in a system that supports communications using transmission time intervals (TTIs) of different durations. A base station may identify a user equipment's (UE) capability to provide HARQ feedback for transmissions that use TTIs of a shorter duration relative to other TTIs supported in the system. The base station may select a HARQ timing mode based on the capability of the UE and may indicate the selected HARQ timing mode to the UE. The base station may then transmit one or more data transmissions to the UE using the reduced TTIs. The UE may respond with HARQ feedback based on the HARQ timing mode. The HARQ timing mode may be based on different response times based on the location of the data transmission within a TTI or relative to data transmission in other TTIs.

Abstract: Antenna selection and reassignment in multiple radio access technology (RAT) communication systems with unlicensed spectrum is disclosed. Aspects include a user equipment (UE) monitoring for a channel reserving signal in each frame from multiple transmission sources. If no channel reserving signal is detected, then the UE reassigns one or more of the antennas previously assigned to the transmission sources with no activity detected. Additional aspects include base stations that determine a clear channel assessment (CCA) status for each of unlicensed carrier designated for transmission to a UE. The base station will transmit a receive antenna usage adjustment signal to the UE based on the determined CCA status.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless device may use a sampling rate that is less than a default sampling rate associated with a wireless carrier. The device may operate in a narrowband portion of a system bandwidth, and the sampling rate may be less than that used by devices monitoring the whole bandwidth. Multiple sampling rates may be used so that a portion of signal processing may be associated with one sampling rate and another portion of the signal processing may be associated with another sampling rate. The size of a cyclic prefix (CP) may be adjusted based on the sampling rate to align subframe timing boundaries for signals of different sampling rates. In some cases, each symbol of a signal may include both a CP and a postfix such that the postfix for each symbol overlaps the prefix of the next symbol.

Abstract: Channel state information (CSI) feedback in long term evolution (LTE) and LTE-Advanced (LTE-A) networks including contention-based shared unlicensed spectrum is disclosed in which a user equipment (UE) identifies at least one carrier utilizing a contention based radio frequency spectrum. The UE detects a transmission signal indicative of clear channel assessment (CCA) result information for the carrier and determines whether a reference signal for channel state information measurement is present in a subframe based on the detected transmission signal. The UE would transmit a measurement report based on this presence determination of the reference signal.

Abstract: Methods, systems, and devices for wireless communication are described. Discontinuous reception (DRX) operation may be configured differently on enhanced component carriers (eCCs) than on other component carriers, including a primary cell (PCell). In some cases, a user equipment (UE) may be configured with several different eCC DRX modes. An eCC DRX configuration may, for example, be coordinated with downlink (DL) transmission time interval (TTI) scheduling so each DRX ON duration may correspond to a DL burst duration of the corresponding eCC. The eCC DRX ON durations may also be scheduled according to hybrid automatic repeat request (HARD) process scheduling. In some examples, eCC DRX ON durations may be based on listen-before-talk (LBT) procedures. In some cases, eCC DRX ON durations may be configured to contain an uplink (UL) burst to enable channel state information (CSI) reporting. The eCC DRX may also be configured to minimize interruption of the PCell.

Abstract: Methods, systems, and apparatuses are described for wireless communications. In one method, a sequence number corresponding to a data frame and one or more data subframes of the data frame may be transmitted over an unlicensed spectrum to a user equipment (UE), and hybrid automatic repeat request (HARQ) feedback for the one or more data subframes may be received over the unlicensed spectrum, from the UE, when the sequence number corresponding to the data frame is received by the UE in a specified order. In another method, a sequence number corresponding to a data frame and HARQ feedback may be transmitted over an unlicensed spectrum to a UE, and one or more data subframes may be received over the unlicensed spectrum, from the UE, in response to the HARQ feedback when the sequence number corresponding to the data frame is received by the UE in a specified order.

Abstract: Aspects of the present disclosure provide techniques for design of synchronization signals for narrowband operation, which can be used for stand-alone/in-band/guard-band deployment. An example method is provided for operations which may be performed by a base station (BS). The example method generally includes generating a primary synchronization signal (PSS) utilizing a first code sequence and a cover code applied to the first code sequence over a first number of symbols within one or more subframes, generating a secondary synchronization signal (SSS) based on a second code sequence over a second number of symbols within one or more subframes, and transmitting the PSS and the SSS in the first and second subframes to a first type of a user equipment (UE) that communicates on one or more narrowband regions of wider system bandwidth.

Abstract: Methods, systems, and devices for wireless communications are described. A transmitter may identify a contention window for a no-energy-detection protocol for determining a channel availability for a data transmission. After the contention window expires, the transmitter may send a request message to a receiver. The receiver may measure a quality of the request message against a request threshold and transmit a response message if the measured quality exceeds the request threshold. The transmitter may then measure a quality of the response message against a response threshold. If the measured quality exceeds the response threshold, the transmitter may initiate a data transmission with the receiver. If the quality falls below the response threshold or the response message is not received, the transmitter may adjust the contention window and reattempt the no-energy-detection protocol. The contention window may also be adjusted based on an acknowledgement message received after the data transmission.

Abstract: Techniques for estimating and reporting channel quality indicator (CQI) are disclosed. Neighboring base stations may cause strong interference to one another and may be allocated different resources, e.g., different subframes. A UE may observe different levels of interference on different resources. In an aspect, the UE may determine a CQI for resources allocated to a base station and having reduced or no interference from at least one interfering base station. In another aspect, the UE may determine multiple CQI for resources of different types and associated with different interference levels. For example, the UE may determine a first CQI based on at least one first subframe allocated to the base station and having reduced or no interference from the interfering base station(s). The UE may determine a second CQI based on at least one second subframe allocated to the interfering base station(s).

Abstract: Methods, systems, and devices for wireless communication are described. A base station may employ a multiplexing configuration based on latency and efficiency considerations. The base station may transmit a resource grant, a signal indicating the length of a downlink (DL) transmission time interval (TTI), and a signal indicating the length of a subsequent uplink (UL) TTI to one or more user equipment (UEs). The base station may dynamically select a new multiplexing configuration by, for example, setting the length of an UL TTI to zero or assigning multiple UEs resources in the same DL TTI. Latency may also be reduced by employing block feedback, such as block hybrid automatic repeat request (HARQ) feedback. A UE may determine and transmit HARQ feedback for each transport block (TB) of a set of TBs, which may be based on a time duration of a downlink TTI.

Abstract: Methods and apparatuses are described in which an unlicensed spectrum is used for Long Term Evolution (LTE) communications. One method includes performing a clear channel assessment (CCA) for an unlicensed spectrum in a current gating interval to determine whether the unlicensed spectrum is available for a transmission in a next transmission interval, and gating OFF the transmission in the unlicensed spectrum for the next transmission interval when the determination is that the unlicensed spectrum is unavailable.