Some embodiments of the present disclosure provide for use of a linear chirp signal as a basis for a sensing signal. Modification of the linear chirp signal by a signature function can allow a receiver of the sensing signal to determine an identity for a source of the sensing signal. Accordingly, upon processing the received sensing signal to obtain path parameter estimates, the receiver can direct a transmission of an indication of the path parameter estimates to the source of the sensing signal. Aspects of the present application relate to performing multi-node, multi-path channel estimation on the basis of processing the received sensing signal. Conveniently, the processing is performed with low complexity.

A scheduled entity measures a power level of a demodulation reference signal (DMRS) prior to blind decoding a physical downlink control channel (PDCCH) candidate associated with the DMRS. The scheduled entity performs blind decoding of the PDCCH candidate if the power level is above a predetermined threshold or foregoes blind decoding if the power level is below the predetermined threshold. A scheduling entity transmits a blind decoding configuration setting to the scheduled entity. The scheduling entity enables, via the blind decoding configuration setting, measurement, at the scheduled entity, of power levels of a plurality of DMRSs prior to blind decoding a plurality of respective PDCCH candidates associated with the plurality of DMRSs. Only PDCCH candidates associated with DMRSs having power levels that are above the predetermined threshold are blind decoded. A predetermined number of PDCCH candidates are scheduled for blind decoding. Blind decoding stops when the predetermined number is reached.

Techniques discussed herein can facilitate transmission and reception of group common PDCCH (Physical Downlink Control Channel) for NR (New Radio). One example embodiment employable by a UE (User Equipment) comprises processing circuitry configured to: process higher layer signaling that configures a set of combinations for slot formats for the UE; detect, via blind decoding on at least a portion of a control resource set, a DCI (Downlink Control Information) message that indicates a combination for slot formats of the set of combinations for slot formats via a SFI (slot format indicator); and determine a slot format for one or more slots based on the indicated combination for slot formats, wherein the slot format indicates, for each symbol of the one or more slots, whether that symbol is DL (Downlink), UL (Uplink), or a flexible symbol in the slot format.

The present disclosure provides a device and a method for determining detection information about search spaces, and relates to the field of communications technology. The method for determining detection information about search spaces includes, in a case that at least two search spaces are being detected by a UE and a sum of initial quantities of pieces of detection information about the at least two search spaces is greater than a total quantity of pieces of detection information supported by the UE, determining a first quantity of pieces of detection information about each of the at least two search spaces. A sum of the first quantities of pieces of detection information about the at least two search spaces is smaller than or equal to the total quantity of pieces of detection information. The detection information includes a PDCCH candidate or PDCCH channel estimate.

Methods, systems, and devices for wireless communications are described. A base station may identify time and frequency resources for a physical downlink shared channel (PDSCH) to be transmitted to a user equipment (UE) in a first transmission time interval (TTI). The base station may transmit configuration information for a control channel search space set in a second TTI. The second TTI may precede the first TTI. The configuration information may include an indication of an absence of a physical downlink control channel (PDCCH) transmission to send in the control channel search space set indicating the identified time and frequency resources for the PDSCH, and a set of time and frequency resources for the control channel search space set. The UE may receive the configuration information and identify the time and frequency resources allocated for the PDSCH in the second TTI, and receive the PDSCH transmission in the second TTI.

The present disclosure provides a downlink control channel detection method, a terminal, and a Base Station (BS). The method includes: obtaining first and second auxiliary information from a BS, in which the first auxiliary information indicates a time-domain duration of a Control Resource Set (CORESET) of a downlink control channel, which is allocated by the BS, the second auxiliary information indicates a resource mapping mode from a Resource Element Group (REG) of CORESET to Control Channel Elements (CCE); performing a blind detection on the downlink control channel, based on the first and second auxiliary information.

Methods, systems, and devices for wireless communication are described. In some cases, due to blind decoding and channel estimation (CE) limits, one or more user equipment (UE) specific search sets may be pruned for blind decoding and/or CE purposes. For instance, after hashing a set of common decoding candidates to control channel elements (CCEs) within the control region, the UE specific search sets may be pruned so as to conform to the blind decode limitation, since a common search space has already occupied a portion of the total blind decode limit. Following pruning, the UE may hash the sets of UE-specific decoding candidates associated with the one or more UE specific search sets to CCEs within the control region. The UE may further prune UE specific search sets, based on CE limits, while reusing CE for overlapping hashed locations.

A semi-blind channel estimation method and apparatus are provided. The semi-blind channel estimation method includes: step S1: obtaining data that includes a first training sequence and that is received by a receive end; step S2: performing minimum mean square error channel estimation based on the data and the prestored first training sequence, to obtain a channel parameter matrix; step S3: detecting the first training sequence by using a least square detection algorithm, to obtain estimated data; and step S4: using the estimated data as a second training sequence, replacing the first training sequence in step S2 with the second training sequence, and cyclically performing step S2 and step S3 on the second training sequence, until a channel parameter matrix obtained last time is the same as a channel parameter matrix obtained this time, and then stopping circulation, to estimate a final channel parameter matrix.

This disclosure relates generally to wireless communications and, more particularly, to systems and methods for uplink signaling using blind channel estimation at a base station. In one embodiment, a method performed by a communication device, includes: associating a time slot with a data packet comprising a head portion and a tail portion, wherein the head portion comprises a communication device identifier and the tail portion comprises user data associated with the head portion; spreading the head portion into a first predetermined transmission format; spreading the tail portion into a second predetermined transmission format; and transmitting the spreaded head portion with the spreaded tail portion to a communication node, wherein the spreaded head portion comprises information to be used by the communication node for channel estimation and for decoding the tail portion to retrieve the user data.

The disclosure provides a subspace-based blind identification algorithm of an ocean underwater acoustic channel for multi-channel fir filter, which adopts a technical solution that a channel impulse response coefficient is calculated by quadratic minimization. The disclosure has beneficial effects that estimation precision can be met when using a proper number of samples, and especially when a few noise vectors are used for estimating channel parameters, so that calculation amount is greatly reduced.