Abstract:
A UE may receive a reference signal or directional synchronization subframe from a base station and transmit a scheduling request to the base station using a resource based on the reference signal or directional synchronization subframe. The scheduling request may enable a base station to grant the UE resources to send a buffer status report (BSR). The resource may be associated with a random access channel (RACH) time period. The UE may also transmit a scheduling request within a frequency region of the RACH time period. The scheduling request may be transmitted based on a received indication of a set of subcarrier, a cyclic shift, or a sequence index. In some examples, the resources used by the UE to send the BSR may include physical uplink shared channel (PUSCH) or physical uplink control channel (PUCCH) resources.
Abstract:
Methods, systems, and devices for wireless communication are described. A base station may identify a sounding reference signal (SRS) configuration for user equipment (UE). The base station may transmit an SRS grant message to a UE indicating the SRS configuration. An indication of SRS parameters may be included in the SRS grant message, and may include the SRS parameters or a location of the SRS parameters. That is, SRS parameters may be transmitted in a control channel with the SRS grant message or may be separately sent in a data channel as indicated by the indication of SRS parameters. In some cases, SRS parameters may be determined based on previously received UE feedback regarding channel conditions or power limitations. Alternatively, the base station may make its own environment measurements or assign SRS parameters autonomously. The UE may signal SRS transmissions to the base station according to the SRS grant message.
Abstract:
Methods, systems, and devices for wireless communication are described. Some examples provide for identifying a primary synchronization signal (PSS) sequence of a synchronization subframe, determining, for the synchronization subframe, an extended synchronization signal (ESS) sequence based at least in part on the PSS sequence and transmitting the synchronization subframe. Other examples provide for generating an ESS sequence for a synchronization subframe to be communicated to a UE, scrambling the ESS sequence based at least in part on cell-specific information associated with the base station and transmitting, to the UE, the scrambled ESS sequence in the synchronization subframe.
Abstract:
A base station may transmit scheduling information comprising one or more first downlink messages to a first user equipment (UE) in a first beam. The base station may transmit one or more second downlink messages to a second UE in a second beam. In response to the transmission of the one or more first downlink messages, the base station may receive one or more first uplink control messages from the first UE in a time slot. In response to the transmission of the one or more second downlink messages, the base station may receive one or more second uplink control messages from the second UE in the same time slot. The one or more second uplink control messages may be frequency-orthogonal or spreading code-orthogonal to the one or more first uplink control messages.
Abstract:
Method, systems, and apparatuses are described for discovery operations in a millimeter wave wireless communication system. A first base station of the millimeter wave wireless communication system may determine a timing parameter and a propagation parameter associated with a second base station of the millimeter wave wireless communication system. The first base station may perform a discovery procedure with the second base station based at least in part on the timing parameter and the propagation parameter. At least a portion of the discovery procedure may be performed wirelessly via the millimeter wave wireless communication system. The first base station may establish a backhaul communication link with the second base station based on the discovery procedure.
Abstract:
Aspects are provided allowing a UE to transmit repetitions of an ULT, PEI-R, or other uplink reference signal for on-demand SSB, RMSI, or paging transmissions. A base station initially transmits an indication of a configured uplink repetition mode, which may comprise a first, second, or third mode in which a one-to-one, one-to-many, or many-to-many mapping exists between downlink reference signals and uplink occasions, respectively. Afterwards, the UE receives downlink reference signals via different transmission beams of the base station. In response to the downlink reference signals, the UE transmits an uplink reference signal repetition in one or more uplink occasions associated with one or more of the downlink reference signals according to the configured uplink repetition mode. In response to the uplink reference signal repetition, the base station may transmit a SSB, RMSI, or paging message. Thus, a balance between network energy savings and uplink signal reliability may be achieved.
Abstract:
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station (BS) may group and selectively multiplex a plurality of random access channel responses (RARs) and radio resource control (RRC) messages in a message B (msgB) communication, together with supplementary scheduling information for other RARs to be mapped to a different msgB communication. The BS may transmit the msgB communication to one or more user equipments. Numerous other aspects are provided.
Abstract:
Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) may perform a random access (RACH) procedure based on a selected synchronization signal block (SSB). During this RACH procedure, a base station may transmit physical downlink control channel (PDCCH) messages for UE RACH message handling. To receive PDCCH signaling for RACH Messages 2, 3, or 4 (Msg 2/3/4), the UE may identify a set of time resources used by the base station for transmitting SSBs that are not quasi-co-located (QCL) with the selected SSB. The UE may identify a Msg 2/3/4 search space that does not overlap with this identified set of resources, and may monitor this identified search space. The search space may correspond to a modified remaining minimum system information (RMSI) search space indicated by the base station, or a valid RMSI search space not indicated by the base station.
Abstract:
Methods, systems, and devices for wireless communications are described. The described techniques provide for selecting a PRACH occasion (RO) based on downlink quality, access congestion, latency (e.g., time to next available RO), beam correspondence, random access in previous transmissions, or combinations of these factors. The user equipment (UE) may detect access congestion of synchronization signal blocks (SSBs) and select the less congested SSB in the RO selection. The UE may detect the access congestion by receiving a back-off indicator from the base station, detecting a contention resolution failure, or the number or media access control (MAC) subheaders in a random access response. In some cases, the ROs associated with different SSBs have different latencies and the UE may select the earliest available RO.
Abstract:
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may monitor for one or more downlink reference signals periodically transmitted from a base station during a first time period. The UE may determine that the UE is to participate in a random access procedure with the base station during a random access occasion, while the UE is operating in a half-duplex communication mode. The UE may identify that a first downlink reference signal is scheduled during a second time period that includes at least one random access occasion that corresponds with a reference signal for which the UE is configured to monitor, where the second time period is a subset of the first time period. As such, the UE may refrain from monitoring for the downlink reference signal during the time period in favor or proceeding with the random access procedure.