Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit a random access preamble to a base station as part of a two-step random access procedure. The UE may generate the preamble by identifying a discrete Fourier transform (DFT) matrix and generating a set of sequences based on the DFT matrix. Each sequence of the set of sequences may be generated by selecting a column of the DFT matrix and performing deterministic sampling of respective entries from the selected column in accordance with a sampling function. The UE may then select a sequence from the set of sequences based on generating the set of sequence. The UE may transmit the selected sequence to a wireless device (e.g., a base station).

A method performed by an apparatus in a wireless local area network (WLAN) is provided. The method comprises: transmitting a first physical layer convergence protocol (PLCP) protocol data unit (PPDU) for a first variant including a first control field and a second PPDU for a second variant including a second control field in A(aggregated)-PPDU, wherein the second PPDU for the second variant is transmitted in duplicate (DUP) mode; and receiving a first response to the first PPDU and a second response to the second PPDU in A-PPDU based on the first control field and the second control field, respectively, wherein the first variant is based on a first protocol standard and the second variant is based on a second protocol standard, and wherein the second protocol standard is beyond version of the first protocol standard.

The disclosure relates to a communication technique for convergence of IoT technology and a 5.sup.th generation (5G) communication system for supporting a higher data transfer rate beyond a 4.sup.th generation (4G) system, and a system therefor. The disclosure can be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart or connected cars, health care, digital education, retail business, and services associated with security and safety) based on 5G communication technology and IoT-related technology. A method according to the disclosure includes receiving configuration information including a parameter for transmission of a synchronization signal block (SSB) from a base station, identifying a resource for transmission of the SSB based on the parameter, and in case that a condition for transmission of the SSB is satisfied, transmitting the SSB to a second terminal on the resource.

The present invention relates to a method and an apparatus which enable a terminal to transmit a signal for device-to-device (D2D) communication in a wireless communication system. Specifically, the present invention transmits a synchronization signal for D2D communication and a demodulation reference signal (DM-RS) for demodulation of the synchronization signal, wherein the base sequence of the demodulation reference signal is generated using a synchronization reference ID.

An access point (AP) generates a multi-user request to send (MU-RTS) frame for protecting a channel bandwidth during a communication exchange, and transmits the MU-RTS frame in multiple duplicate first packets in respective communication subchannels that span the channel bandwidth. Each first packet has a first packet format that conforms to a legacy protocol. The AP receives multiple clear-to-send (CTS) frames from multiple client stations via respective communication subchannels that span the channel bandwidth. The AP generates a trigger frame configured to prompt the multiple client stations to transmit respective data to the AP. After transmitting the multiple first packets, the AP transmits the trigger frame in one or more second packets that span the channel bandwidth and that conform to a second packet format defined by a non-legacy protocol. The AP receives, from the multiple client stations, data frames that are responsive to the trigger frame.

Aspects of the present disclosure relate to methods and apparatus for location encoding for secondary synchronization signals (SSS) to convey additional information, such as a current symbol number. According to aspects, a method is provided herein for wireless communications that may be performed, for example, by a base station (BS). The method generally includes selecting frequency resources to use for transmitting synchronization signals in a symbol of a frame, wherein the frequency resources are selected based on a mapping of frequency resources to a location of the symbol within the frame; and transmitting synchronization signals to at least one user equipment (UE) according to the mapping. As a result, the UE may receive synchronization signals, determine a location of the current symbol in a frame based on the mapping, and synchronize to the BS based on the determined location of the current symbol. Numerous other aspects are provided.

This application discloses a communications method and apparatus. The method includes: obtaining, by a terminal device, downlink synchronization signal block index information; receiving, by the terminal device, information used to indicate an association relationship between a random access resource RO and a synchronization signal block; and accessing, by the terminal device, a network device based on the information on an RO corresponding to the synchronization signal block index information. This application further discloses a corresponding apparatus. A time-frequency location of a random access resource associated with each downlink synchronization signal is indicated, so that the terminal device obtains, through downlink synchronization, a time-frequency location for sending an uplink random access signal, to avoid a blind attempt of the terminal device and a beam mismatch of the network device occurring when the network device receives a random access signal, thereby improving efficiency.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may perform a transmission detection procedure on each base station before combining control information. The UE may use demodulation reference signals (DMRS) as a detection mechanism. If the UE detects a DMRS from a base station, the UE may determine that a control resource set associated with the base station is valid for combining. If the UE does not detect DMRS from the base station, the UE may refrain from combining control information from the base station. In another example, base stations that pass a listen-before-talk (LBT) pr6ocedure may transmit a preamble before transmitting control information. A preamble may carry a preamble sequence associated with a specific control resource set. The UE may identify a preamble sequence and determine that the corresponding control resource set is valid for control information combining.

An extensible communication system is described herein. The system includes a first module for receiving a root index value and for generating a constant amplitude zero auto-correlation sequence based on the root value. The system further includes a second module for receiving a seed value and for generating a Pseudo-Noise sequence based on the seed value. The system further includes a third module for modulating the constant amplitude zero auto-correlation sequence by the Pseudo-Noise sequence and for generating a complex sequence. The system further includes a fourth module for translating the complex sequence to a time domain sequence, wherein the fourth module applies a cyclic shift to the time domain sequence to obtain a shifted time domain sequence.

This application provides a signal transmission method and apparatus. The method includes: receiving, by a first device, configuration information sent by a third device and used to indicate a quantity of times for which the third device sends a signal group, in other words, learning in advance, based on the configuration information, a quantity of receive beams that can be measured, and selecting, after receiving first signals of the quantity an optimal receive beam from receive beams that have been detected, to avoid continuously detecting more first signals for selection.