Certain aspects of the present disclosure provide techniques and apparatus for random access channel communications in non-terrestrial networks. A method that may be performed by a user equipment (UE) includes transmitting a physical random access channel (PRACH) preamble to the network entity in a random access (RA) occasion; and monitoring for a random access response (RAR) within a RAR window with a start position determined based at least in part on the RA occasion, round trip time parameters for non-terrestrial network communications, and one or more timing offset parameters.

Disclosed are techniques for wireless communication. In an aspect, a user equipment (UE) receives, during a first state, a configuration of a sounding reference signal (SRS) resource or SRS resource set, obtains an association between the SRS resource or SRS resource set and a group of random access channel (RACH) resources, and transmits, while outside the first state, a group of RACH signals using transmission properties based on the association between the SRS resource or SRS resource set and the group of RACH resources, wherein the group of RACH resources spans a plurality of adjacent frequency resources over a single time resource, or the group or RACH resources spans the plurality of adjacent frequency resources over a plurality of time resources.

One embodiment of the present specification relates to a method for performing low-latency communications. According to one embodiment, an interframe space (IFS) for low-latency data may be suggested. The interframe space for low-latency data may be set to be greater than PIFS and smaller than DIFS. On the basis of the interframe space for low-latency data, a reception STA may perform EDCA and transmit low-latency data to a transmission STA.

A wireless communications protocol in which multiple-link operations provide enhanced efficiency in particular for non-simultaneous transmit receive (NSTR) communications between stations (STAs) of multiple-link devices (MLDs). When MLD1 is the TXOP holder of Link1 and the channel is accessed on Link2 by MLD2 for transmitting to MLD1; MLD2 immediately transmits over Link2 to MLD1, if MLD1 is receiving on Link1. MLD2 transmits a frame over Link2 to occupy the channel if MLD1 is transmitting on Link1, then when MLD1 is receiving on Link1 then MLD2 transmits another frame to MLD1.

Methods and apparatuses for a channel access in a wireless communication systems. A method of a UE in a wireless communication system, the method comprising: determining whether, for a first time duration, a channel is sensed as an idle state for a channel access procedure; occupying the channel for a second time duration based on a determination that the channel is sensed as the idle state; and transmitting, for at least a portion of the second time duration, a signal on the channel, wherein the first time duration and the second time duration are based on a SL PPPP for a SL communication.

Techniques and examples of design for initial access in New Radio (NR) unlicensed spectrum (NR-U) are described. An apparatus receives from a base station of a wireless network which transmits one or multiple synchronization signal and PBCH blocks (SS/PBCH blocks) whose indices are indicated in a cyclic-wrapped order subject to a result of listen-before-talk (LBT) in NR-U. The apparatus also transmits a random access request on random access channel (RACH) resources allocated by the base station.

A method for configuring a random access occasion, the method comprising: an access network device sends RO configuration parameters, the configuration parameters comprising: the shift value of the starting position of a shared RO relative to the starting position of an RO adopted for four-step random access, the shared RO being an RO shared by four step random access and two step random access.

There is provided mechanisms for determining time-of-arrival of a PRACH preamble. A method is performed by a radio access network node. The radio access network node is configured for beamformed communication in a set of beams. The method comprises receiving, from a UE and at a TRP of the radio access network node, a PRACH preamble. The method comprises determining a weight factor value for the PRACH preamble. The weight factor value is dependent on beam information mapped to the PRACH preamble. The beam information identifies one of the beams in the set of beams. The method comprises determining time-of-arrival of the PRACH preamble using hypothesis testing that incorporates the weight factor value.

A method and a device in a node used for wireless communication are disclosed in the present disclosure. A first node transmits a first sequence and a first radio signal, the first sequence being associated with the first radio signal, the first sequence being transmitted on a first random-access channel, and a first bit block being used for generating the first radio signal; receives a second radio signal, the second radio signal comprising a first information block; and transmits a second sequence and a third radio signal, the second sequence being associated with the third radio signal, and the second sequence being transmitted on a second random-access channel, the first bit block being used for generating the third radio signal; the first information block comprises a first sequence index, the first sequence index corresponds to the first sequence.

The disclosure provides communication methods and apparatuses. One example method includes that a terminal device sends a random access request to a network device, and the terminal device receives a random access response to the random access request that comprises first configuration information from a network device. The first indication information indicates not to perform channel access or the first indication information indicates that a channel access type is channel access without random back-off or channel access with random back-off with variable size of contention window. The terminal device sends an uplink message to the network device based on the first indication information, where the uplink message is carried on a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH).