Systems and methods are disclosed for random access in a wireless communication system such as, e.g., a wireless communication system having a non-terrestrial (e.g., satellite-based) radio access network. Embodiments of a method performed by a wireless device and corresponding embodiments of a wireless device are disclosed. In some embodiments, a method performed by a wireless device for random access comprises performing an open-loop timing advance estimation procedure to thereby determine an open-loop timing advance estimate for an uplink between the wireless device and a base station. The method further comprises transmitting a random access preamble using the open-loop timing advance estimate. In this manner, random access can be performed even in the presence of a long propagation delay such as that present in a satellite-based radio access network. Embodiments of a method performed by a base station and corresponding embodiments of a base station are also disclosed.

Disclosed are a method and apparatus for transmitting an uplink channel in a wireless communication system. A method for transmitting an uplink channel in a wireless communication system supporting an sTTI is performed by a terminal incapable of the simultaneous transmission of a first uplink channel and a second uplink channel, and includes when a first uplink channel region at a first sTTI overlaps a specific symbol included in a second uplink channel region at a second sTTI, transmitting the first uplink channel to a base station using at least one of a plurality of symbols included in the first uplink channel region symbol other than the specific symbol at the first sTTI and transmitting the second uplink channel to the base station using at least one symbol included in the second uplink channel region at the second sTTI. The specific symbol includes a symbol to which a DMRS related to the second uplink channel is mapped.

The present invention relates to a wireless communication system. More particularly, the present invention relates to a method for acquiring uplink synchronization in a terminal having a plurality of cells in a carrier aggregation-based wireless communication system and an apparatus therefor, the method comprising the steps of: transmitting a random access preamble on a first cell; receiving a random access response message including an uplink timing adjustment value for the first cell after transmitting the random access preamble; and performing uplink transmission in the first cell by using the uplink timing adjustment value, wherein a transmission time point of the random access preamble is given based on a specific time point related to a second cell.

A system and method are disclosed for synchronizing timing for a terminal in a satellite communication system. Upon detecting a service interruption, first timing markers are extrapolated from timing information received prior to the service interruption. Second timing markers are also extrapolated from timing information received subsequent to the service interruption. Timing for the terminal is then synchronized with the gateway based on a timing difference between the first timing markers and the second timing markers.

An electronic device according to an embodiment includes an mmWave communication module and a processor. The processor is configured to receive a first signal transmitted by a first external electronic device, identify a distance of a transmission path of the first signal, transmit a second signal, receive a third signal obtained when the second signal is reflected, identify a distance of a transmission path of the second signal based on a difference between a transmission time of the second signal and a reception time of the third signal, and determine whether the transmission path of the first signal is a line of sight (LoS) path between the electronic device and the first external electronic device based on a difference between the distance of the transmission path of the first signal and the distance of the transmission path of the second signal. In addition, other embodiments are possible.

Systems and methods are disclosed for random access in a wireless communication system such as, e.g., a wireless communication system having a non-terrestrial (e.g., satellite-based) radio access network. Embodiments of a method performed by a wireless device and corresponding embodiments of a wireless device are disclosed. In some embodiments, a method performed by a wireless device for random access comprises performing an open-loop timing advance estimation procedure to thereby determine an open-loop timing advance estimate for an uplink between the wireless device and a base station. The method further comprises transmitting a random access preamble using the open-loop timing advance estimate. In this manner, random access can be performed even in the presence of a long propagation delay such as that present in a satellite-based radio access network. Embodiments of a method performed by a base station and corresponding embodiments of a base station are also disclosed.

Disclosed is an improved implementation of a flood fill mesh network that utilizes low power and does not require any network addressing or routing protocol for network message delivery. Network messages are only communicated to a network node's correspondents using broadcast network messages over a wireless network. Network messages propagate throughout the network based on each correspondent node rebroadcasting received messages to its correspondent nodes, and so on. Coordinated synchronization across network nodes can be achieved by each network node broadcasting synchronization frames to its correspondents within a synchronization window time period and thereafter adjusting its own start time for the next synchronization period to converge synchronization. A guard band may also be utilized to account for any clock drift and signal path delays between any two communicating network nodes.

High-frequency communications in 5G and especially 6G will require precise synchronization of user devices with the base station, including setting the user device clock time and clock rate. The base station can assist user devices by periodically providing a guard-space timestamp point, at which a phase or amplitude of the timing signal abruptly changes in the middle of the guard-space of a particular resource element or a particular OFDM symbol. A receiver can determine precisely the time of arrival of the timestamp point, and correct its clock setting to agree with the time of the timestamp point. The receiver can then provide uplink messages aligned with the base station's clock, by adding a previously determined timing advance to each uplink transmission. In addition, the user device can measure two guard-space timing signals with a predetermined separation, thereby adjusting the clock rate.

A method and system of synchronizing a local clock with a master clock using a serial communication bus includes receiving by a serial data interface receiver a master time signal corresponding to a master clock, generating by a frequency tuning loop a time error signal corresponding to a difference between the master time signal and a local time signal, generating by the frequency tuning loop an actual frequency signal based on a base frequency and the time error signal, producing by the frequency tuning loop a command frequency error based on the actual frequency signal and the local time signal, and producing by the local clock an updated local time signal based on the command frequency error.

The user devices in managed networks, such as 5G and 6G networks, are required to adapt their uplink transmissions to the base station’s resource grid, including the timing and frequency structure of the resource grid. Message-heavy legacy synchronization procedures can consume substantial resources. Therefore, a simpler, faster procedure is disclosed in which synchronization parameters are standardized where possible, timing signals are configured in minimal size where possible, and the user device collaborates with the base station to adjust the user device’s clock setting, clock rate, timing advance (to match the base station’s symbol boundaries), and Doppler correction (to match the base station’s subcarrier frequency), without exchanging data messages other than very brief timing signals. Such ultra-lean synchronization procedures may enable low-complexity synchronization in future high-frequency communications.