US-12621874-B2 - Random access method and device for reduced capability terminal in wireless communication system

Abstract

Disclosed is a random access method and apparatus for a reduced capability user equipment in a wireless communication system. A method of performing random access by a UE in a wireless communication system according to an embodiment of the disclosure may include an operation of receiving random access-related configuration information from a base station; an operation of determining at least one of a RACH occasion (RO) group related to random access preamble transmission, one or more ROs, and a random access preamble group based on at least one of the random access-related configuration information, a UE type, and a repetition level; and an operation of transmitting one or more random access preambles in each of the one or more ROs.

Inventors

• Dong Hyun Park

Assignees

• Innovative Technology Lab Co., Ltd.

Dates

Publication Date

20260505

Application Date

20220902

Priority Date

20200305

Claims (20)

1. 1 . A method performed by a first wireless user device, the method comprising: receiving, from a base station: at least one random access parameter for a first group of wireless user devices, wherein the first group of wireless user devices provide at least one capability unavailable for a second group of wireless user devices; at least one random access parameter for the second group of wireless user devices, wherein the second group of wireless user devices comprises the first wireless user device; and system information indicating at least one of: at least one parameter associated with a plurality of wireless user devices, wherein the plurality of wireless user devices comprises the first group of wireless user devices and the second group of wireless user devices; or at least one reduced capability parameter associated with the second group of wireless user devices; selecting, based on the at least one random access parameter for the second group of wireless user devices, a random access resource comprising at least one of: a random access preamble resource configured for the second group of wireless user devices; or a random access channel (RACH) occasion configured for the second group of wireless user devices; and transmitting, to the base station and based on the selected random access resource, a random access preamble, wherein the second group of wireless user devices comprises at least one reduced capability user device, and wherein the first wireless user device is a reduced capability user device.
2. 2 . The method of claim 1 , wherein the first wireless user device provides at least one reduced capability comprising at least one of: a reduced bandwidth capability; a reduced antenna capability; a reduced transmission power capability; or a reduced half-duplex capability.
3. 3 . The method of claim 1 , wherein the at least one random access parameter for the second group of wireless user devices indicates at least one of: a starting preamble associated with the second group of wireless user devices; or a number of preambles associated with the second group of wireless user devices.
4. 4 . The method of claim 3 , wherein the at least one random access parameter for the second group of wireless user devices comprises: a first preamble parameter indicating the starting preamble; and a second preamble parameter indicating the number of preambles, and wherein the selecting the random access resource comprises: selecting, based on the first preamble parameter and the second preamble parameter, a random access preamble as the random access preamble resource configured for the second group of wireless user devices.
5. 5 . The method of claim 4 , wherein the selected random access preamble comprises at least one of: a message A (MsgA) preamble configured for a two-step random access procedure; or a message 1 (Msg1) preamble configured for a four-step random access procedure.
6. 6 . The method of claim 1 , wherein the at least one random access parameter for the second group of wireless user devices indicates a mask index associated with the RACH occasion configured for the second group of wireless user devices.
7. 7 . The method of claim 6 , wherein the mask index indicates a subset of RACH occasions associated with the second group of wireless user devices, and wherein the subset of RACH occasions is comprised in RACH occasions shared among the first group of wireless user devices and the second group of wireless user devices.
8. 8 . The method of claim 1 , wherein the at least one random access parameter for the second group of wireless user devices comprises: a random access configuration associated with a four-step random access; and a random access configuration associated with a two-step random access.
9. 9 . The method of claim 1 , further comprising: receiving, from the base station, a random access response; and receiving, from the base station and via a downlink channel configured for a reduced capability user device, at least one of: downlink control information; or downlink shared channel data.
10. 10 . The method of claim 1 , wherein the at least one random access parameter for the second group of wireless user devices comprises a parameter for a message 3 (Msg3) for the second group of wireless user devices.
11. 11 . The method of claim 1 , wherein the at least one reduced capability parameter associated with the second group of wireless user devices comprises a system information block (SIB) parameter indicating an initial uplink bandwidth part dedicated to the second group of wireless user devices, and wherein the transmitting the random access preamble comprises transmitting, via the initial uplink bandwidth part dedicated to the second group of wireless user devices, the random access preamble.
12. 12 . A method performed by a base station, the method comprising: transmitting, to at least one wireless user device comprising a first wireless user device: at least one random access parameter for a first group of wireless user devices, wherein the first group of wireless user devices provide at least one capability unavailable for a second group of wireless user devices; at least one random access parameter for the second group of wireless user devices, wherein the second group of wireless user devices comprises the first wireless user device; and system information indicating at least one of: at least one parameter associated with a plurality of wireless user devices, wherein the plurality of wireless user devices comprises the first group of wireless user devices and the second group of wireless user devices; or at least one reduced capability parameter associated with the second group of wireless user devices; receiving, from the first wireless user device and based on a random access resource associated with the at least one random access parameter for the second group of wireless user devices, a random access preamble, wherein the random access resource comprises at least one of: a random access preamble resource configured for the second group of wireless user devices; or a random access channel (RACH) occasion configured for the second group of wireless user devices; after receiving the random access preamble, determining that the first wireless user device belongs to the second group of wireless user devices, wherein the determining is based on at least one of: the random access preamble, the random access preamble resource; or the RACH occasion; and transmitting, to the first wireless user device, a random access response associated with the received random access preamble, wherein the second group of wireless user devices comprises at least one reduced capability user device, and wherein the first wireless user device is a reduced capability user device.
13. 13 . The method of claim 12 , wherein the first wireless user device provides at least one reduced capability comprising at least one of: a reduced bandwidth capability; a reduced antenna capability; a reduced transmission power capability; or a reduced half-duplex capability.
14. 14 . The method of claim 12 , wherein the at least one random access parameter for the second group of wireless user devices indicates at least one of: a starting preamble associated with the second group of wireless user devices; or a number of preambles associated with the second group of wireless user devices.
15. 15 . The method of claim 14 , wherein the at least one random access parameter for the second group of wireless user devices comprises: a first preamble parameter indicating the starting preamble; and a second preamble parameter indicating the number of preambles, and wherein the random access preamble is one of a plurality of random access preambles associated with: the first preamble parameter; and the second preamble parameter.
16. 16 . The method of claim 15 , wherein the received random access preamble comprises at least one of: a message A (MsgA) preamble configured for a two-step random access procedure; or a message 1 (Msg1) preamble configured for a four-step random access procedure.
17. 17 . The method of claim 12 , wherein the at least one random access parameter for the second group of wireless user devices indicates a mask index associated with the RACH occasion configured for the second group of wireless user devices.
18. 18 . The method of claim 17 , wherein the mask index indicates a subset of RACH occasions associated with the second group of wireless user devices, and wherein the subset of RACH occasions is comprised in RACH occasions shared among the first group of wireless user devices and the second group of wireless user devices.
19. 19 . The method of claim 12 , wherein the at least one random access parameter for the second group of wireless user devices comprises: a random access configuration associated with a four-step random access; and a random access configuration associated with a two-step random access.
20. 20 . The method of claim 12 , further comprising: after transmitting the random access response, transmitting, to the first wireless user device and via a downlink channel configured for a reduced capability user device, at least one of: downlink control information; or downlink shared channel data.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of International patent application No. PCT/KR2021/002672, filed on Mar. 4, 2021, which claims priority from and the benefit of Korean Patent Application No. 10-2020-0027883, filed on Mar. 5, 2020, each of which is hereby incorporated by reference in its entirety. BACKGROUND 1. Field The disclosure relates to random access in a wireless communication system, and particularly, to a random access method and apparatus for a user equipment (UE) with reduced capability, compared to a legacy UE. 2. Discussion of the Background The 3rd Generation Partnership Project (3GPP) New Radio (NR) system may support various numerologies in association with the standard of a time-frequency resource unit in consideration of various scenarios, service requirements, potential system compatibility, and the like, in order to satisfy requirements for 5th (5G) communication. Also, to overcome a poor channel environment, such as high pathloss, phase-noise, and frequency offset, occurring on a high carrier frequency, the NR system may support transmission of a physical signal/channel through a plurality of beams. Through this, the NR system may support applications, for example, enhanced Mobile Broadband (eMBB), massive Machine Type Communications (mMTC)/ultra Machine Type Communications (uMTC), and Ultra Reliable and Low Latency Communications (URLLC). Here, mMTC, URLLC, and TSC may be associated with the utilization of an advanced Internet of Things (IoT) in consideration of the vertical industrial world. Such applications may be supported in the same network. Discussions have been conducted in order to support a new type of device in the 3GPP NR system. For example, the new type of device may include industrial wireless sensors, video surveillance, and wearable devices. Services for such new type of device have a higher requirement than a low power wide area network (LPWAN) such as the legacy LTE-MTC (LTE M) or narrow band-IoT (NB-IoT), but have a lower requirement than eMBB or URLLC. Given the above-described feature, such new types of device may be referred to as a reduced capability (RC) device. A method of supporting an RC UE in the 3GPP NR system has been discussed, and particularly, a specific method for random access by an RC UE has not been provided. SUMMARY An aspect of the disclosure is to provide a new random access method and apparatus for an RC user equipment (UE) in a wireless communication system. Another aspect of the disclosure is to provide a method and apparatus for identifying an RC UE in a network during initial access by a UE. Another aspect of the disclosure is to provide a method and apparatus for identifying an RC UE in a network during a random access preamble transmission process performed by a UE. The technical subject matters of the disclosure are not limited to the above-mentioned technical subject matters, and other technical subject matters which are not mentioned may be understood by those skilled in the art based on the following description. A method of performing random access by a user equipment (UE) in a wireless communication system according to an aspect of the disclosure may include an operation of receiving random access-related configuration information from a base station, an operation of determining at least one of a RACH occasion (RO) group related to random access preamble transmission, one or more ROs, and a random access preamble group based on at least one of the random access-related configuration information, the type of UE, and a repetition level, and an operation of transmitting one or more random access preambles in each of the one or more ROs. Features briefly described above in relation to the present disclosure are merely example aspects of the following detailed description and do not limit the scope of the present disclosure. According to the disclosure, a new random access method and apparatus for an RC user equipment (UE) in a wireless communication system can be provided. According to the disclosure, a method and apparatus for identifying an RC UE in a network during initial access by a UE can be provided. According to the disclosure, a method and apparatus for identifying an RC UE in a network during a random access preamble transmission process performed by a UE can be provided. Effects achievable from the present disclosure are not limited to the aforementioned effects and still other effects not described herein may be clearly understood by one of ordinary skill in the art to which the present disclosure pertains from the following description. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating an NR frame structure to which the disclosure is applicable. FIG. 2 is a diagram illustrating an NR resource structure to which the disclosure is applicable. FIG. 3 is a diagram illustrating an NR random access procedure to which the disclosure is applicable. FIG. 4 is a diagram illust