Example methods and apparatus for determining a timing advance are described. One example method includes obtaining ephemeris information of a satellite, where the ephemeris information includes coordinates of the satellite and an ephemeris error of the satellite. A timing advance is determined according to a preset rule based on the ephemeris information and location information of a terminal device, where the location information includes coordinates of the terminal device and a positioning error of the terminal device. The preset rule is determined by using a first horizontal distance, a first vertical distance, the ephemeris error, and the positioning error.

A timing advance sending method and a timing advance sending apparatus that improves the efficiency of a communication network. The efficiency of the communication network is improved by sending relative timing advance to a base station, where the relative timing advance is determined based on a relationship between a distance between the terminal and a non-terrestrial network device and a distance from the network device to an earth reference point. The determined relative timing advance is relatively small in comparison with a propagation delay corresponding to all communication links between the terminal and the base station, so that a number of bits that requires to be occupied is relatively small and thus a number of bits that requires to be occupied by the terminal to report the relative timing advance is relatively small, which helps to save communication resources.

Example methods and apparatus for determining a timing advance are described. One example method includes obtaining ephemeris information of a satellite, where the ephemeris information includes coordinates of the satellite and an ephemeris error of the satellite. A timing advance is determined according to a preset rule based on the ephemeris information and location information of a terminal device, where the location information includes coordinates of the terminal device and a positioning error of the terminal device. The preset rule is determined by using a first horizontal distance, a first vertical distance, the ephemeris error, and the positioning error.

A random access method and device are provided, which can reduce the bit used to indicate the TA. The method includes: a terminal device determines a first TA:, the terminal device sends a first message in a random access process based on the first TA.

Provided are a method by which a first device performs wireless communication, and a device for supporting same are provided. The method can comprise the steps of: receiving information related to a sidelink (SL) bandwidth part (BWP); receiving, from a network, SL synchronization priority order information set through global navigation satellite systems (GNSS)-based synchronization; receiving, from the network, information for indicating whether selection of a base station (BS)-related synchronization reference is disabled; detecting, on the basis of the information for indicating that the selection of the base station-related synchronization reference is disabled, a synchronization signal transmitted through the SL BWP by a GNSS-related synchronization reference or other UEs; and performing synchronization with respect to the GNSS-related synchronization reference or one synchronization reference from among the other UEs on the basis of the synchronization signal.

One disclosure of this specification provides a method for receiving a synchronization signal block (SSB) by a user equipment (UE). The method may include: determining frequency locations of multiple SSBs; and receiving at least one SSB among the multiple SSBs. The multiple SSBs may be configured to be arranged spaced apart from each other by a predetermined offset. The at least one SSB may be located at an interval of 1.2 MHz on a frequency axis.

The embodiments of the present application relate to a method and device for determining a timing advance, applied to the establishment of a timing advance in a random access process of an NTN system. The method in the embodiments of the present application includes: receiving and acquiring relevant parameters in a configuration message, wherein the relevant parameters include cell common time delay information; and determining, according to the cell common time delay information, an uplink timing advance of an uplink transmission timing position with respect to a configuration message receiving position. With regard to cell common time delay information existing in the NTN system, an uplink transmission timing position is determined, and a PRACH Preamble is sent in advance, so that the problem when applied to the establishment of the timing advance in the random access process of the NTN system is solved, and the calculation accuracy of the timing advance in a data transmission process after the random access process is ensured.

A method and system for determining inroute frame timing for a Very Small Aperture Terminal (VSAT) includes receiving an appointment to transmit, on an inroute, at a start of a slot X of a frame number M; establishing, at a VSAT, an arrival time of a super frame numbering packet (SFNP) including a satellite ephemeris vector and a frame number N; calculating, at the VSAT, a timing offset (T.sub.RO) to be applied to the arrival time to compensate for a time varying gateway-satellite-terminal propagation delay (T.sub.HS+T.sub.SR); setting a transmit instant as an end of the T.sub.RO after the arrival time; adding to the transmit instant a duration of X slots and a duration of (M-N) frames; and transmitting a burst, on the inroute from the VSAT, at the transmit instant. In the method, the calculating is based on computing T.sub.HS+T.sub.SR from the satellite ephemeris vector, a gateway transmits the SFNP and receives the burst in the slot X within the frame number M of the inroute, and N is greater than or equal to M. A method and system for using ephemeris data for inroute timing is disclosed.

Apparatuses, methods, and systems for estimating a propagation time between a first node and a second node of a wireless network are disclosed. One method includes determining a first time propagation delay between the first node and the second node based on location of the second node and the kinematic information of a third node, receiving, by the second node, a packet from the first node containing a timestamp representing a transmit time of the packet from the first node, determining a second time propagation delay between the first node and the second node based upon the difference between the reception time of the packet, and the first time stamp included within the packet, transmitting, by a second node a TX packet after a holding delay based on the first propagation delay and the second propagation delay.

A terminal device determines the time domain location, where the time domain location is a time domain location of the RSS of the neighbor cell in the timing of the neighbor cell; determines a first sequence parameter of the RSS of the neighbor cell; and measures the RSS of the neighbor cell based on the time domain location and the first sequence parameter of the RSS of the neighbor cell.