EP-4226729-B1 - METHOD AND APPARATUS FOR RANDOM ACCESS IN WIRELESS COMMUNICATION SYSTEM

EP4226729B1EP 4226729 B1EP4226729 B1EP 4226729B1EP-4226729-B1

Inventors

JUNG, Byounghoon
LEE, SANGHO
CHA, Jiyoung
LEE, HYUNJOONG
JUNG, JUNGSOO

Dates

Publication Date: 20260513
Application Date: 20211110

Claims (15)

A method performed by a terminal in a wireless communication system, the method comprising: receiving (1110), from a base station, a first signal including at least one reference signal; selecting (1120) a reference signal by measuring the at least one reference signal; transmitting (1130), to the base station, a second signal through a first uplink resource corresponding to the selected reference signal; receiving (1140), from the base station, a message including information on a physical random access channel, PRACH, resource corresponding to the selected reference signal based on the second signal; and transmitting (1150), to the base station, a random access preamble through the PRACH resource corresponding to the selected reference signal.
The method of claim 1, wherein the at least one reference signal comprises at least one of a synchronization signal block, SSB, or a channel state information reference signal, CSI-RS, and wherein at least one of information on first uplink resources corresponding to each reference signal, or information on a resource through which the message is transmitted is received through the first signal or a separate signal.
The method of claim 1, wherein the selecting the reference signal comprises: measuring the at least one reference signal; and selecting (1120) the reference signal having a best signal strength among the at least one reference signal based on the measuring of the at least one reference signal.
The method of claim 1, wherein the second signal is a signal having predetermined energy or a signal having a sequence shorter than a sequence of the random access preamble.
A method performed by a base station in a wireless communication system, the method comprising: transmitting (1210), to a terminal, a first signal including at least one reference signal; receiving (1220), from the terminal, a second signal through a first uplink resource corresponding to a reference signal selected by the terminal; identifying a physical random access channel, PRACH, resource corresponding to the reference signal selected by the terminal, based on the second signal; transmitting (1230), to the terminal, a message including information on the PRACH resource corresponding to the reference signal selected by the terminal, based on the second signal; and receiving (1240), from the terminal, a random access preamble through the PRACH resource.
The method of claim 5, wherein the at least one reference signal comprises at least one of a synchronization signal block, SSB, or a channel state information reference signal, CSI-RS, and wherein at least one of information on first uplink resources corresponding to each reference signal, or information on a resource through which the message is transmitted is transmitted through the first signal or a separate signal.
The method of claim 5, wherein the reference signal have a best signal strength among the at least one reference signal.
The method of claim 5, wherein the second signal is a signal having predetermined energy or a signal having a sequence shorter than a sequence of the random access preamble.
A terminal in a wireless communication system, the terminal comprising: a transceiver; and a controller configured to: receive (1110), from a base station via the transceiver, a first signal including at least one reference signal, select (1120) a reference signal by measuring the at least one reference signal, transmit (1130), to the base station via the transceiver, a second signal through a first uplink resource corresponding to the selected reference signal, receive (1140), from the base station via the transceiver, a message including information on a physical random access channel, PRACH, resource corresponding to the selected reference signal based on the second signal; and transmit (1150), to the base station via the transceiver, a random access preamble through the PRACH resource corresponding to the selected reference signal.
The terminal of claim 9, wherein the at least one reference signal comprises at least one of a synchronization signal block, SSB, or a channel state information reference signal, CSI-RS, and wherein at least one of information on first uplink resources corresponding to each reference signal, or information on a resource through which the message is transmitted is received through the first signal or a separate signal.
The terminal of claim 9, wherein the controller is further configured to: measure the at least one reference signal; and select (1120) the reference signal having a best signal strength among the at least one reference signal based on the measuring of the at least one reference signal.
The terminal of claim 9, wherein the second signal is a signal having predetermined energy or a signal having a sequence shorter than a sequence of the random access preamble.
A base station in a wireless communication system, the base station comprising: a transceiver; and a controller configured to: transmit (1210), to a terminal via the transceiver, a first signal including at least one reference signal, receive (1220), from the terminal via the transceiver, a second signal through a first uplink resource corresponding to a reference signal selected by the terminal, identify a physical random access channel, PRACH, resource corresponding to the reference signal selected by the terminal, based on the second signal, transmit (1230), to the terminal via the transceiver, a message including information on the PRACH resource corresponding to the reference signal selected by the terminal, based on the second signal; and receive (1240), from the terminal via the transceiver, a random access preamble through the PRACH resource.
The base station of claim 13, wherein the at least one reference signal comprises at least one of a synchronization signal block, SSB, or a channel state information reference signal, CSI-RS, and wherein at least one of information on first uplink resources corresponding to each reference signal, or information on a resource through which the message is transmitted is transmitted through the first signal or a separate signal.
The base station of claim 13, wherein the reference signal have a best signal strength among the at least one reference signal, and wherein the second signal is a signal having predetermined energy or a signal having a sequence shorter than a sequence of the random access preamble.

Description

[Technical Field] The disclosure relates to a wireless communication system. More particularly, the disclosure relates to a method and an apparatus for performing random access to a base station (BS) by a user equipment (UE) in a wireless communication system. [Background Art] A review of the development of mobile communication from generation to generation shows that the development has mostly been directed to technologies for services targeting humans, such as voice-based services, multimedia services, and data services. It is expected that connected devices which are exponentially increasing after commercialization of 5th generation (5G) communication systems will be connected to communication networks. Examples of things connected to networks may include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machines, and factory equipment. Mobile devices are expected to evolve in various formfactors, such as augmented reality glasses, virtual reality headsets, and hologram devices. In order to provide various services by connecting hundreds of billions of devices and things in the 6th generation (6G) era, there have been ongoing efforts to develop improved 6G communication systems. For these reasons, 6G communication systems are referred to as Beyond-5G systems. 6G communication systems, which are expected to be implemented approximately by 2030, will have a maximum transmission rate of tera (1,000 giga)-level bps and a radio latency of 100µsec, and thus will be 50 times as fast as 5G communication systems and have the 1/10 radio latency thereof. In order to accomplish such a high data transmission rate and an ultra-low latency, it has been considered to implement 6G communication systems in a terahertz band (for example, 95GHz to 3THz bands). It is expected that, due to severer path loss and atmospheric absorption in the terahertz bands than those in mmWave bands introduced in 5G, a technology capable of securing the signal transmission distance (that is, coverage) will become more crucial. It is necessary to develop, as major technologies for securing the coverage, multi antenna transmission technologies including radio frequency (RF) elements, antennas, novel waveforms having a better coverage than orthogonal frequency division multiplexing (OFDM), beamforming and massive multiple input multiple output (MIMO), full dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas. In addition, there has been ongoing discussion on new technologies for improving the coverage of terahertz-band signals, such as metamaterial-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS). Moreover, in order to improve the frequency efficiencies and system networks, the following technologies have been developed for 6G communication systems: a full-duplex technology for enabling an uplink (UE transmission) and a downlink (node B transmission) to simultaneously use the same frequency resource at the same time; a network technology for utilizing satellites, high-altitude platform stations (HAPS), and the like in an integrated manner; a network structure innovation technology for supporting mobile nodes B and the like and enabling network operation optimization and automation and the like; a dynamic spectrum sharing technology though collision avoidance based on spectrum use prediction, an artificial intelligence (AI)-based communication technology for implementing system optimization by using AI from the technology design step and internalizing end-to-end AI support functions; and a next-generation distributed computing technology for implementing a service having a complexity that exceeds the limit of UE computing ability by using super-high-performance communication and computing resources (mobile edge computing (MEC), clouds, and the like). In addition, attempts have been continuously made to further enhance connectivity between devices, further optimize networks, promote software implementation of network entities, and increase the openness of wireless communication through design of new protocols to be used in 6G communication systems, development of mechanisms for implementation of hardware-based security environments and secure use of data, and development of technologies for privacy maintenance methods. It is expected that such research and development of 6G communication systems will enable the next hyper-connected experience in new dimensions through the hyper-connectivity of 6G communication systems that covers both connections between things and connections between humans and things. Particularly, it is expected that services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas could be provided through 6G communication systems. In addition, with enhanced security and reliability, services such as remote surgery, industrial automation, and emerg