Abstract: Dual-thread feedback for non-orthogonal channels used in wireless communications systems is described. A first feedback thread may employ transmission strategy (TS) independent feedback and a second feedback thread may employ TS dependent feedback. The first feedback thread may include channel feedback from channel measurements (e.g., channel gain, noise covariance, etc.) and may be fed back periodically. A TS space may be determined that includes combinable TSs for UEs that may be grouped for non-orthogonal techniques, and one or more TS sets may be sent to the UEs. UEs may determine channel quality and/or other channel state information (CSI) for the TSs and report CSI for one or more TSs of the TS sets in a second feedback thread. Scheduling may be performed for transmissions to the UEs based on the feedback in the first and/or second feedback threads.

Abstract: Joint aspects of coordinated multiple (CoMP) operations is discussed between multiple entities that may be in different CoMP clusters or even deployed by different operators. Participating base stations obtain channel related information such as sounding reference signals (SRS), channel state information (CSI), and the like from one or more neighbor user equipments (UE) served by a different base station. The base station determines a channel estimate at the neighbor UEs using the channel related information and selects a beamforming vector and schedules downlink transmissions to a served UE based on the channel estimates incorporating the channels of the other neighbor UEs. The selected beamforming vectors and transmission schedules minimizes the interference at the neighbor UEs.

Abstract: Methods, systems, and devices are described for wireless communication. A device may use enhanced reporting mechanisms to support control information reporting on shared spectrum. In some cases, a device may utilize enhanced component carriers (eCCs) for data transmissions. In one example, the device may transmit control information (e.g., ACK/NACK, CSI, etc.) to a corresponding device using a CCA exempt transmission (CET). In another example, a device may report control information quasi-periodically. For instance, a device may be assigned a specified interval and a control feedback window for reporting control information (e.g., CSI). The window may provide a duration prior and subsequent to the specified interval during which a UE may transmit control information. For example, the device may perform a CCA reserving the channel for a duration that does not include the specified interval but may transmit feedback information based on determining the specified interval falls within the assigned window.

Abstract: Synchronization techniques for wireless nodes in a shared radio frequency spectrum band may include performing a listen before talk (LBT) procedure (e.g., a clear channel assessment (CCA) procedure) at identified resynchronization boundaries and initiating transmissions following successful LBT procedures. In the event that a node loses synchronization between resynchronization boundaries, such as due to an unsuccessful LBT procedure, the node becomes unsynchronized and may initiate an LBT procedure separate from the other nodes of the set of nodes. At a subsequent resynchronization boundary, the unsynchronized node may perform a resynchronization procedure in order to again become synchronized with other nodes of the set of nodes. In cases where the resynchronization procedure is unsuccessful, a parameter associated with the resynchronization procedure may be adapted to increase an interval for performing the resynchronization procedure.

Abstract: Techniques for performing network-assisted peer discovery to enable peer-to-peer (P2P) communication are described. In one design, a device registers with a network entity (e.g., a directory agent) so that the presence of the device and possibly other information about the device can be made known to the network entity. The network entity collects similar information from other devices. The device sends a request to the network entity, e.g., during or after registration. The request includes information used to match the device with other devices, e.g., information about service(s) provided by the device and/or service(s) requested by the device. The directory agent matches requests received from all devices, determines a match between the device and at least one other device, and sends a notification to perform peer discovery. The device performs peer discovery in response to receiving the notification from the network entity.

Abstract: Methods, systems, and devices for wireless communication are described. A base station may transmit a configuration for enhanced paging to a UE being served by a cell over a shared frequency band. The enhanced paging may include multiple paging intervals for each paging cycle. The UE may enable reception for a paging interval and determine whether the UE receives a downlink transmission. The UE may lengthen a paging interval or enable reception during a second paging interval based in part on determining whether the UE receives a downlink transmission. In some examples, the UE may receive a paging queue status indication indicating that paging information will be transmitted during a paging interval or a later interval, or indicating that no paging information is present at a serving cell.

Abstract: Channel feedback reporting for non-orthogonal wireless communication systems employing frequency selective channels. A plurality of channel feedback matrices corresponding to a plurality of sub-carriers of a sub-band for a non-orthogonal channel may be determined by a UE, and one or more effective channel feedback matrices for the sub-band may be determined based on the plurality of channel feedback matrices. Each of the one or more effective channel feedback matrices may be associated with corresponding sets of transmission strategies, where each of the corresponding sets of transmission strategies include one or more transmission strategies of a plurality of transmission strategies for the non-orthogonal channel.

Abstract: Techniques for supporting distributed multiple-input multiple-output (MIMO) transmissions are described. In one design, a user equipment (UE) determines channel estimates for multiple cells and reports the channel estimates. The UE thereafter receives a data transmission sent by the multiple cells to the UE based on the channel estimates. The data transmission may include at least one data stream, and each data stream may be sent by one cell or the multiple cells to the UE. In another design, a UE determines first and second channel estimates for first and second cells, respectively, and reports the channel estimates. The UE then receives a first data transmission sent by the first cell to the UE based on the first channel estimate. The UE also receives a second data transmission sent by the second cell to another UE and steered away from the UE based on the second channel estimate.

Abstract: Techniques for synchronization across transmitting nodes of a same public land mobile network (PLMN) operator using a shared radio frequency spectrum band may include initiating, at a first wireless node, a listen-before-talk (LBT) procedure for access to the shared radio frequency spectrum band, and identifying that a second wireless node associated with a same PLMN operator as the first wireless node has won contention for the shared radio frequency spectrum band. The first wireless node may discontinue the LBT procedure and initiate an auxiliary transmission using the shared radio frequency spectrum band concurrently with a primary transmission of the second wireless node.

Abstract: Uplink short transmissions (ULSTs) may be configured in a wireless communications system to be transmitted in configured uplink resources within a listen-before-talk (LBT) frame or within a ULST window during which a user equipment (UE) may transmit a ULST and during which the base station may monitor for ULSTs. A UE having an amount of data to be transmitted that is less than a threshold value may transmit the data in the ULST, and avoid the need to have the base station allocate separate uplink resources outside of the configured uplink resources or the ULST window.

Abstract: Methods, systems, and devices for wireless communication are described. A base station may identify a transmission opportunity duration and an allocation for downlink and uplink transmissions, then broadcast a channel reservation request transmission. The broadcast may be sent using unlicensed radio frequency spectrum over a channel that includes multiple-sub-bands. The channel reservation transmission may include the identified duration, allocation, and a channel state information (CSI) request. User equipments (UEs) may receive the broadcast, and respond with a channel reservation response transmission that includes a CSI report, a transmit identity, or an interference threshold indicator. In some cases, some or all of the UEs may transmit a sounding reference signal (SRS) in response to an SRS request that is broadcast by the base station. The base station may schedule uplink and/or downlink transmissions to at least a subset of the multiple UEs based on the channel reservation response and/or SRS.

Abstract: Multi-channel channel state information (CSI) design is disclosed for long term evolution (LTE)/LTE-Advanced (LTE-A) systems with unlicensed spectrum. A “reference” CSI process defined for each channel/carrier. The reference CSI process is defined across each channel in any particular band that the transmitter is configured to support. The transmit power for such reference CSI processes is spread equally over each such channel. In order to report CSI for a subset of channels under an unequal power split assumption, a user equipment (UE) may apply a different power offset in the computation of the CSI process. Alternatively, an auxiliary CSI process may be defined for reporting CSI of a subset of channels with unequal distribution of powers across different channels in a band.

Abstract: A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus may be a UE that acquires information regarding an interfering non-serving cell and uses the information to improve decoding of serving cell signals. The method includes receiving, from a serving evolved Node B (eNB), information that includes one or more transmission characteristics of at least one non-serving cell and performing at least one of interference cancellation, demodulation, or provides an improved channel quality indicator (CQI) based on the received information.

Abstract: Methods, systems, and devices are described for a system that supports wireless communication with a first set of devices using a first OFDM symbol duration associated with a first tone spacing (i.e., a first physical layer (PHY) configuration) and second set of devices using a PHY configuration associated with a second tone spacing. A base station may transmit a set of discovery reference signals (DRS) in a narrowband region of a primary channel of a carrier. The DRS may have the first PHY configuration and a secondary channel of the carrier may support communications using the second PHY configuration. The base station may transmit a first system information (SI) message for one set of devices using the first PHY configuration, and it may transmit a second SI message for another set of devices using the second PHY configuration.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless communication system may utilize a listen before talk (LBT) procedure prior to transmission. A base station may perform an enhanced clear channel assessment (eCCA) on one channel and a single clear channel assessment (CCA) on another channel. The base station may then send a grant for a user equipment (UE) to transmit on both channels. The UE may receive the grant, and perform a single CCA on the first channel and an eCCA on the second channel. The UE may then transmit uplink information on both the first channel and the second channel. That is, the base station may send an opportunistic grant for transmitting on the second channel even though it may not have passed eCCA at the base station. The UE may then use the channel if it passes an eCCA.

Abstract: Methods, systems, and devices for wireless communication are described. A transmitting device, which may be configured without a radio link control (RLC) layer, may receive a packet data convergence protocol (PDCP) protocol data unit (PDU) at a media access control (MAC) layer. The device may then generate a set of transport blocks at the MAC layer using the PDCP PDU and transmit them over a wireless connection. A receiving device, which may also be configured without an RLC layer, may receive the transport blocks at the MAC layer, generate a MAC service data unit (SDU), and convey the MAC SDU to a PDCP. In some cases, the receiving device may then send an acknowledgement (ACK) or negative acknowledgement (NACK) for each transport block that includes a portion of the PDCP PDU, and the transmitting device may indicate to the PDCP layer whether the PDCP PDU was successfully received.

Abstract: A device may support communication without a radio link control (RLC) layer, which may include receiving a packet data convergence protocol (PDCP) service data units (SDUs) for multiple radio bearers at a PDCP layer. The multiple radio bearers may have different reliability or delay targets, and a reordering procedure at the PDCP layer may be conducted on the different radio bearers. The reordering procedure may be a same reordering procedure for each of the radio bearers, with one or more parameters that may be adjusted based on one or both of the reliability target or delay target of the radio bearer.

Abstract: Methods, systems, and devices for wireless communication using various coding schemes for data transmission are described. A wireless communication system may support multiple coding schemes such as, for example, turbo codes and low density parity check codes. The system may support selection of the coding scheme based on explicit signaling or implicit evaluation of transmission parameters. A transmitting device may select a coding scheme, encode a message using the selected coding scheme, and transmit the encoded message over a wireless connection. The receiving device may receive the encoded message, select the coding scheme, and decode the message using the select coding scheme.

Abstract: Techniques are described for wireless communication. One method of wireless communication includes receiving, at a first user equipment (UE), a first communication over a shared radio frequency spectrum band from a first base station. The first communication includes a pre-grant communication associated with a downlink transmission or a grant of uplink resources associated with an uplink transmission. The method further includes determining, based at least in part on receiving the first communication, whether a channel reservation signal is detected over the shared radio frequency spectrum band; and transmitting a second communication over the shared radio frequency spectrum band, to the first base station, based at least in part on the determining. The second communication includes an approval of the downlink transmission or the uplink transmission.

Abstract: Channel clearance using a shared radio frequency spectrum band may be performed for both a base station and a user equipment (UE). A base station may perform a listen before talk (LBT) procedure and verify one or more channels in a shared radio frequency spectrum band are available for transmissions and, if the LBT procedure is successful, transmit a pre-grant transmission to one or more UEs. The UEs may perform an LBT procedure for channel(s) indicated in the pre-grant transmission. If the UE LBT procedure passes, the UE may transmit a channel clearance signal, and may transmit a feedback communication responsive to the pre-grant transmission. The feedback communication may indicate, for example, the pre-grant transmission was received and which of the one or more channels are available based on the LBT procedure. The base station may receive the feedback communication and initiate transmissions to the UE.