Abstract: Base stations (such as small cells) may support active and dormant states. To facilitate state transitions, these cells may transmit discovery signals. The transmission design of both discovery signals and network synchronization signals from small cells should provide for regular periodicity, while supporting the benefit of transitioning between active and dormant states. Disclosed is a method, a computer program product, and an apparatus that determine a first reference signal for at least one of discovery or measurement, and a second reference signal for synchronization, where both the first reference signal and the second reference signal are based on a same type of reference signal.

Abstract: Base stations (such as small cells) may support active and dormant states. To facilitate state transitions, these cells may transmit discovery signals. The transmission design of both discovery signals and network synchronization signals from small cells should provide for regular periodicity, while supporting the benefit of transitioning between active and dormant states. Disclosed is a method, a computer program product, and an apparatus that determine a first reference signal for at least one of discovery or measurement, and a second reference signal for synchronization, where both the first reference signal and the second reference signal are based on a same type of reference signal.

Abstract: Reference signals may not uniformly span over time and/or frequency on a resource unit. For example, reference signals may non-uniformly occupy symbols of a subframe. Alternatively, reference signals normally transmitted over certain tones of a subframe may have to be punctured to avoid collisions with a PSS and/or SSS transmitted over the same tones. Consequently, a UE may only be able to use a subset of reference signal tones for performing channel estimation. Accordingly, a method, an apparatus, and a computer program product for wireless communication are provided for improving channel estimation under a non-uniform signal pattern. The apparatus indicates to a UE to utilize a subset of reference signals to derive a channel estimate for demodulating data in a specific subframe, and transmits a plurality of subframes, the plurality of subframes including the reference signals and the specific subframe, the specific subframe including a PSS and/or SSS.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may identify a set of non-overlapping periodic intervals for monitoring a synchronization signal, which may be composed of or may include a repeated sequence; and the UE may identify possible timing structure (e.g., subframe, slot, etc.) boundaries using the intervals. The UE may then determine that one of the possible boundaries is a boundary using a second synchronization signal. For instance, the UE may perform a cumulative correlation during each of a series of correlation periods corresponding to the periodic intervals. Each of the cumulative correlations may contain multiple coherent correlations associated with the sequence repetitions. From the cumulative correlations, the UE may identify possible boundaries. The UE may perform a secondary correlation based on a second synchronization signal for each possible boundary in order to determine the system timing.

Abstract: A wireless device may determine a coverage enhancement (CE) level (or coverage extension) by attempting to decode a received broadcast signal. The wireless device may attempt to decode a portion of the broadcast signal using a CE level that is less than the CE level of the broadcast. If the decoding attempt is successfully, the CE level may be declared as an operating CE level. If decoding is unsuccessful, the CE level may be increased decoding retried. The wireless device may continue to test-decode the broadcast signal at new (e.g., increasing) CE levels until a CE level is sufficient for a decode and is declared the operating CE level of the wireless device. In some cases, the wireless device test-decodes a broadcast channel after selecting a CE level based on a path loss measurement of a downlink signal (e.g., reference signal).

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: Certain aspects of the present disclosure generally relate to wireless communications, and more specifically to determining uplink narrowband regions based on downlink resources. An example method generally includes identifying one or more uplink narrowband regions within a wider system bandwidth, based on downlink resources, and communicating using at least one of the identified narrowbands.

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.

Abstract: Certain aspects of the present disclosure relate to methods and apparatus for mitigating resource conflicts between ultra low latency (ULL) and legacy transmissions. A base station may determine a region of a subframe having overlapping resource allocations for a first device of a first type (e.g., ULL device) and a second device of a second type (e.g., legacy device), wherein the first device of the first type has a capability to perform certain procedures with low latency relative to the second device of the second type that lacks the capability. The base station may modulate data from the region of the subframe for transmission to the first and the second devices, using a hierarchical modulation scheme.

Abstract: Methods, systems, and devices are described for wireless communication at a device. Demodulation reference signals (DMRS) may be used to facilitate demodulation of low latency control or data channels, or both. A wireless communication device may, for example, identify a carrier configuration with transmission time intervals (TTIs) of different durations. A carrier may be configured with TTIs that support low latency operations. A DMRS pattern for resources of a low latency TTI may be determined, and that first DMRS pattern may be based on a DMRS pattern for resources of another, longer-duration TTI. Devices may thus communicate using resources of a low latency TTI based on the first DMRS pattern. For example, a user equipment (UE) may demodulate resources of a low latency channel using the first DMRS pattern, and the first DMRS pattern may be consistent with DMRS patterns supporting non-low latency within a common wireless system.

Abstract: Methods for managing hybrid automatic repeat request (HARQ) feedback are disclosed, where HARQ feedback operations by a receiving device may be modified. A receiving device may receive a data transmission. The receiving device may evaluate a condition for determining how to provide HARQ feedback in response to the data transmission. The receiving device may modify a HARQ feedback operation based at least in part on the condition. Modification of HARQ feedback operations may include turning off HARQ feedback, excluding negative acknowledgment (NAK) reporting, or excluding acknowledgement (ACK) reporting.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless system utilizing one or more time-division duplexing (TDD) configured carriers may utilize a dual transmission time interval (TTI) structure (e.g., at the subframe level and symbol-level). The symbol level TTIs may be referred to as low latency (LL) TTIs, and may be organized within LL subframes. A LL subframe may be a subframe that is scheduled for transmissions in one direction (e.g., uplink or downlink, according to a TDD configuration) and may include multiple LL symbols scheduled for both uplink (UL) and downlink (DL) transmissions. Guard periods may be scheduled between adjacent LL symbols that have opposite directions of transmission to enable user equipment (UEs) to transition from receiving mode to transmit mode (or vice versa). The LL subframes may be transparent to receiving devices that do not support LL operations.

Abstract: A system and method for frequency diversity uses interleaving in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) with various FFT sizes. Subcarriers of one or more interlaces are interleaved in a bit reversal fashion and the one or more interlaces are interleaved.

Abstract: The embodiments utilize OFDM symbols to communicate network IDs. The IDs are encoded into symbols utilizing the network IDs as seeds to scramble respective pilots that are then transmitted by utilizing the symbols. The pilots can be structured into a single OFDM symbol and/or multiple OFDM symbols. The single symbol structure for transmitting the network IDs is independent of the number of network ID bits and minimizes frequency offset and Doppler effects. The multiple symbol structure allows a much coarser timing accuracy to be employed at the expense of transmitting additional symbols. Several embodiments employ a search function to find possible network ID candidates from a transmitted symbol and a selection function to find an optimum candidate from a network ID candidate list.

Abstract: Aspects of the present disclosure provide techniques that may be applied in systems to allow for communication over a control channel utilizing a relatively narrow band (e.g., six physical resource blocks) based search space. An exemplary method, performed by a user equipment, generally includes identifying, within a subframe, a first search space to monitor for a downlink control channel that occupies a first number of physical resource blocks (PRBs) that represents a narrowband size and monitoring at least the first search space for the downlink control channel transmitted in the subframe.

Abstract: Methods, systems, and devices are described for reference signal design in wireless communications. A base station may select a reference signal density scheme from a set of available density schemes associated with a port count. The reference signal density scheme may also be selected based on the category of the mobile device receiving the reference signal transmissions. The reference signal density scheme may be a higher density reference signal density scheme or a lower density reference signal density scheme, where the higher density reference signal density scheme includes more reference signal resource elements per subframe. The mobile device may determine the reference signal density scheme based on characteristics of a channel. The higher density reference signal density scheme may provide additional channel estimation opportunities for the mobile device. In some cases, the mobile device sends the channel estimated based on the received reference signals to the base station.

Abstract: A system and method for frequency diversity uses interleaving in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) with various FFT sizes. Subcarriers of one or more interlaces are interleaved in a bit reversal fashion and the one or more interlaces are interleaved in the bit reversal fashion.

Abstract: System(s) and method(s) are provided to facilitate generating and processing acquisition pilots in wireless communications. Acquisition pilots that convey timing and frequency synchronization information, wireless system acquisition and system determination information are modulated with pseudorandom sequences. The R bits of information carried by the acquisition pilot that conveys system determination information are augmented with T bits that convey a counter index associated with the system timing of superframes transmitted from an access point. The processing overhead resulting from the addition of the T bits is offset by the advantages afforded to a wireless communication. Salient advantages include: (i) processing gain at a receiver for communication in a specific sector during asynchronous operation, (ii) packet boundary determination through the counter field values, and (iii) initialization of various pseudorandom registers employed for communication.

Abstract: Techniques for sending sector/system information in TDM pilots using a hierarchical pilot structure are described. A base station sends multiple sets of bits for the sector/system information in multiple TDM pilots. The set of bits sent in a given TDM pilot may include bits sent in earlier TDM pilots. In one design, the base station generates a first TDM pilot based on a first set of bits, generates a second TDM pilot based on a second set of bits that includes the first set, generates a third TDM pilot based on all bits for the information, and sends the TDM pilots. A terminal performs detection to obtain a first detected value for the first TDM pilot, performs detection based on the first detected value to obtain a second detected value for the second TDM pilot, and performs detection based on the first and second detected values to obtain a third detected value for the third TDM pilot.

Abstract: Base stations (such as small cells) may support active and dormant states. To facilitate state transitions, these cells may transmit discovery signals. The transmission design of both discovery signals and network synchronization signals from small cells should provide for regular periodicity, while supporting the benefit of transitioning between active and dormant states. Disclosed is a method, a computer program product, and an apparatus that determine a first reference signal for at least one of discovery or measurement, and a second reference signal for synchronization, where both the first reference signal and the second reference signal are based on a same type of reference signal.