Method and apparatus for performing communication in wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a user equipment (UE) includes receiving, from a base station (BS), configuration information regarding a plurality of physical random access channel (PRACH) transmission occasions frequency-division multiplexed in one time instance, wherein the plurality of PRACH transmission occasions include a first PRACH transmission occasion that is a non-additional PRACH transmission occasion and a second PRACH transmission occasion that is an additional PRACH transmission occasion; and determining a minimum random access (RA) frequency resource index of the second PRACH transmission occasion to be greater than a maximum RA frequency resource index of the first PRACH transmission occasion.

Description

METHOD AND APPARATUS FOR PERFORMING COMMUNICATION IN WIRELESS COMMUNICATION SYSTEM

[0001] The present disclosure relates to the technical field of wireless communications, and in particular, to a communication method, a user equipment (UE) and a base station.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] As random access is an important research direction in a communication system, how to improve the performance of random access for users is a problem to be urgently solved.

[0009] A method performed by a user equipment (UE) includes receiving, from a base station (BS), configuration information regarding a plurality of physical random access channel (PRACH) transmission occasions frequency-division multiplexed in one time instance, wherein the plurality of PRACH transmission occasions include a first PRACH transmission occasion that is a non-additional PRACH transmission occasion and a second PRACH transmission occasion that is an additional PRACH transmission occasion; and determining a minimum random access (RA) frequency resource index of the second PRACH transmission occasion to be greater than a maximum RA frequency resource index of the first PRACH transmission occasion.

[0010] In order to more clearly explain the technical solutions in the embodiments of the present disclosure, the accompanying drawings to be used in the description of the embodiments of the present disclosure will be briefly described below.

[0011] FIG. 1 is a schematic diagram of an overall structure of a wireless network according to an embodiment of the present disclosure;

[0012] FIG. 2a is a schematic diagram of a transmit path according to an embodiment of the present disclosure;

[0013] FIG. 2b is a schematic diagram of a receive path according to an embodiment of the present disclosure;

[0014] FIG. 3a is a schematic diagram of a structure of a UE according to an embodiment of the present disclosure;

[0015] FIG. 3b is a schematic diagram of a structure of a base station according to an embodiment of the present disclosure;

[0016] FIG. 4 is a schematic flowchart of a method performed by a UE according to an embodiment of the present disclosure;

[0017] FIG. 5a is a schematic diagram of a first method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0018] FIG. 5b is a schematic diagram of a second method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0019] FIG. 5c is a schematic diagram of a third method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0020] FIG. 6a is a schematic diagram of a fourth method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0021] FIG. 6b is a schematic diagram of a fifth method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0022] FIG. 6c is a schematic diagram of a sixth method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0023] FIG. 7 is a schematic diagram of a seventh method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0024] FIG. 8 is a schematic diagram of an eighth method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0025] FIG. 9 is a schematic diagram of a ninth method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0026] FIG. 10 is a schematic diagram of a tenth method for determining first random access frequency resource indexes according to an embodiment of the present disclosure;

[0027] FIG. 11 is a schematic diagram of a flow of receiving a random access response by a UE according to an embodiment of the present disclosure;

[0028] FIG. 12 is a schematic flowchart of another method performed by a UE in a communication system according to an embodiment of the present disclosure;

[0029] FIG. 13 is a schematic diagram of a 4-step random access procedure according to an embodiment of the present disclosure; and

[0030] FIG. 14 is a schematic diagram of a structure of an electronic device according to an embodiment of the present disclosure.

[0031] An object of embodiments of the present disclosure is intended to be able to solve the technical problem of how to improve the reliability of random access on the basis of realizing network energy saving.

[0032] According to an aspect of embodiments of the present disclosure, there is provided a method performed by a user equipment (UE), the method comprises: receiving, from a base station (BS), configuration information regarding a plurality of physical random access channel (PRACH) transmission occasions frequency-division multiplexed in one time instance, wherein the plurality of PRACH transmission occasions include a first PRACH transmission occasion that is a non-additional PRACH transmission occasion and a second PRACH transmission occasion that is an additional PRACH transmission occasion; and determining a minimum random access (RA) frequency resource index of the second PRACH transmission occasion to be greater than a maximum RA frequency resource index of the first PRACH transmission occasion, wherein the maximum RA frequency resource index of the first PRACH transmission occasion is determined based on a number of frequency resources for the first PRACH transmission occasion included in the configuration information.

[0033] According to an aspect of embodiments of the present disclosure, there is provided a method performed by a base station (BS), the method comprises: transmitting, to a user equipment (UE), configuration information regarding a plurality of physical random access channel (PRACH) transmission occasions frequency-division multiplexed in one time instance, wherein the plurality of PRACH transmission occasions include a first PRACH transmission occasion that is a non-additional PRACH transmission occasion and a second PRACH transmission occasion that is an additional PRACH transmission occasion; and in case that a preamble for a random access (RA) is received from the UE, transmitting a random access response based on a RA-network temporary identifier (RNTI), wherein the RA-RNTI is determined based on a RA frequency resource index of the first PRACH transmission occasion or the second PRACH transmission occasion, a minimum RA frequency resource index of the second PRACH transmission occasion is determined to be greater than a maximum RA frequency resource index of the first PRACH transmission occasion, and the maximum RA frequency resource index of the first PRACH transmission occasion is determined based on a number of frequency resources for the first PRACH transmission occasion included in the configuration information.

[0034] According to an aspect of embodiments of the present disclosure, there is provided a method performed by a user equipment (UE) in a communication system, the method comprises: receiving first information, the first information being used to indicate first random access resources; transmitting a preamble on a first uplink resource, the first uplink resource being determined based on the first random access resources indicated by the first information; and if first downlink control information is received in a second time window, monitoring a physical downlink control channel (PDCCH) for receiving a random access response based on a first random access radio network temporary identifier (RA-RNTI) in the second time window, wherein the first downlink control information is used to indicate the first random access resources, and the first RA-RNTI is determined based on the first uplink resource and the first downlink control information.

[0035] Optionally, monitoring the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window, comprises: monitoring the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window in a case that the first random access resources indicated by the first information is different from the first random access resources indicated by the first downlink control information.

[0036] Optionally, monitoring the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window, comprises: monitoring the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window in a case that at least one of the following conditions is satisfied: the PDCCH is not monitored; or the PDCCH is monitored, but the least significant bit (LSB) of a system frame number (SFN) of the monitored PDCCH is different from a corresponding LSB of an SFN of the first uplink resource.

[0037] Optionally, monitoring the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window, comprises at least one of: after a first time interval in which the first downlink control information is received, monitoring the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window; or within the first time interval in which the first downlink control information is received, monitoring the PDCCH for receiving the random access response based on a second RA-RNTI, the second RA-RNTI being determined based on the first uplink resource, wherein the first time interval is an valid time interval for the first downlink control information.

[0038] Optionally, the first RA-RNTI is determined based on at least one of: the first uplink resource and the first random access resources indicated by the first downlink control information; a frequency resource index of the first uplink resource and a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information; the frequency resource index of the first uplink resource and a number of frequency domain resources respective to the first random access resources indicated by the first information; the frequency resource index of the first uplink resource, the number of frequency domain resources respective to the first random access resources indicated by the first downlink control information, and the number of frequency domain resources respective to the first random access resources indicated by the first information; or a number of frequency domain resources respective to configured second random access resources.

[0039] Optionally, the first RA-RNTI is determined based on random access resource related information of the first uplink resource, the random access resource related information being used to indicate whether the first uplink resource is related to a second feature.

[0040] Optionally, the first random access frequency resource indexes are determined based on at least one of: a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources; a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources; the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources; the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; or the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0041] Optionally, a minimum of the first random access frequency resource indexes is greater than a maximum of the second random access frequency resource indexes, the maximum of the second random access frequency resource indexes is determined based on the number of frequency domain resources of the second random access resources, and the first random access frequency resource indexes are in ascending order of frequencies from low to high based on the number of frequency domain resources of the first random access resources, starting from the frequency start location of the first random access resources.

[0042] Optionally, the first random access frequency resource indexes are determined based on the following formula:

[0043]

[0044] where denotes a frequency-domain resource index of the first random access resources, denotes the number of frequency domain resources of the first random access resources, denotes the total number of frequency domain resources, and denotes a modulo operation.

[0045] Optionally, the first information indicates that the first random access resources are activated and / or deactivated, the activated first random access frequency resource indexes being determined based on at least one of: a frequency start location of the activated first random access resources and a number of frequency domain resources of the activated first random access resources; a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the activated first random access resources; the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and the number of frequency domain resources of the second random access resources; the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and a total number of frequency domain resources of the random access resources; or the frequency start location of the activated first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0046] Optionally, the first information indicates that the first random access resources are activated and / or deactivated, the first uplink resource is a first available first random access resource among the activated first random access resources; and / or, the first uplink resource is selected from the configured second random access resources and the activated first random access resources in accordance with a first criterion; and / or, the first uplink resource is a first available random access resource among the second random access resources and the activated first random access resources; wherein the first criterion comprises at least one of: if the second random access resources and the activated first random access resources are time-division multiplexed, the first uplink resource is the first available random access resource among the second random access resources and the activated first random access resources; or if the second random access resources and the activated first random access resources are frequency-division multiplexed, the first uplink resource is the first available first random access resource among the activated first random access resources.

[0047] Optionally, the first information and / or the first downlink control information comprises at least one of: mask information for mapping of synchronization signal blocks (SSBs) to the activated first random access resources; a period index for mapping of SSBs to the activated first random access resources; a physical random access channel (PRACH) association period index; a PRACH association pattern period index; at least one fourth RA-RNTI; a reference fourth RA-RNTI and a number of the fourth RA-RNTIs; a frequency unit index; or a time unit index.

[0048] Optionally, the first information comprises random access related configuration information and / or downlink control information.

[0049] Optionally, the method further comprises: after receiving the first downlink control information, transmitting a preamble based on first transmission power, the first transmission power being determined based on a first power step, the first power step being determined by the first downlink control information.

[0050] According to another aspect of embodiments of the present disclosure, there is provided another method performed by a user equipment (UE) in a communication system, the method comprises: receiving first information, the first information being used to indicate first random access resources; transmitting a preamble on a first uplink resource, the first uplink resource being determined based on the first random access resources indicated by the first information; and if first downlink control information is received in a second time window, stopping the second time window and transmitting a preamble on a second uplink resource, the second uplink resource being determined based on the first downlink control information, transmission power for transmitting the preamble on the second uplink resource being related to a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information.

[0051] Optionally, stopping the second time window and transmitting the preamble on the second uplink resource, comprises: stopping the second time window and transmitting the preamble on the second uplink resource in a case that the first random access resources indicated by the first information are different from the first random access resources indicated by the first downlink control information.

[0052] Optionally, stopping the second time window and transmitting the preamble on the second uplink resource, comprises: stopping the second time window and transmitting the preamble on the second uplink resource in a case that a second random access radio network temporary identifier (RA-RNTI) is different from a third RA-RNTI, wherein the second RA-RNTI is determined based on the first uplink resource and the third RA-RNTI is determined based on the second uplink resource.

[0053] Optionally, stopping the second time window and transmitting the preamble on the second uplink resource, comprises: stopping the second time window and transmitting the preamble on the second uplink resource in a case that at least one of the following conditions is satisfied: the PDCCH is not monitored; or the PDCCH is monitored, but the least significant bit (LSB) of a system frame number (SFN) of the monitored PDCCH is different from a corresponding LSB of an SFN of the first uplink resource.

[0054] Optionally, an interval between a transmission time of transmitting the preamble on the second uplink resource and an end time of the second time window is greater than a second time interval, the second time interval being preset and / or determined based on a capability of the UE.

[0055] Optionally, the transmission power for transmitting the preamble on the second uplink resource is determined based on a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information and at least one threshold.

[0056] Optionally, frequency resource indexes of the first random access resources are determined based on at least one of: a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources; a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources; the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources; the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; or the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0057] Optionally, a minimum frequency resource index of the first random access resources is greater than a maximum frequency resource index of the second random access resources, the maximum frequency resource index of the second random access resources is determined based on the number of frequency domain resources of the second random access resources, and the first random access frequency resource indexes are in ascending order of frequencies from low to high, based on the number of frequency domain resources of the first random access resources, starting from the frequency start location of the first random access resources.

[0058] Optionally, the first random access frequency resource indexes are determined based on the following formula:

[0059]

[0060] where denotes a frequency-domain resource index of the first random access resources, denotes the number of frequency domain resources of the first random access resources, denotes the total number of frequency domain resources, and denotes a modulo operation.

[0061] Optionally, the first information indicates that the first random access resources are activated and / or deactivated, the activated first random access frequency resource indexes being determined based on at least one of: a frequency start location of the activated first random access resources and a number of frequency domain resources of the activated first random access resources; a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the activated first random access resources; the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and the number of frequency domain resources of the second random access resources; the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and a total number of frequency domain resources of the random access resources; or the frequency start location of the activated first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0062] Optionally, the first information indicates that the first random access resources are activated and / or deactivated, the first uplink resource is a first available first random access resource among the activated first random access resources; and / or, the first uplink resource is selected from the configured second random access resources and the activated first random access resources in accordance with a first criterion; and / or, the first uplink resource is a first available random access resource among the second random access resources and the activated first random access resources; wherein the first criterion comprises at least one of: if the second random access resources and the activated first random access resources are time-division multiplexed, the first uplink resource is the first available random access resource among the second random access resources and the activated first random access resources; or if the second random access resources and the activated first random access resources are frequency-division multiplexed, the first uplink resource is the first available first random access resource among the activated first random access resources.

[0063] Optionally, the first information and / or the first downlink control information comprises at least one of: mask information for mapping of synchronization signal blocks (SSBs) to the activated first random access resources; a period index for mapping of SSBs to the activated first random access resources; a physical random access channel (PRACH) association period index; a PRACH association pattern period index; at least one fourth RA-RNTI; a reference fourth RA-RNTI and a number of the fourth RA-RNTIs; a frequency unit index; or a time unit index.

[0064] Optionally, the first information comprises random access related configuration information and / or downlink control information.

[0065] According to yet another aspect of embodiments of the present disclosure, there is also provided yet another method performed by a user equipment (UE) in a communication system, the method comprises: receiving first configuration information related to a first random access and second configuration information related to a second random access, wherein the first configuration information is related to a second feature; transmitting a preamble on a first uplink resource, the first uplink resource being determined based on the first configuration information; and monitoring a physical downlink control channel (PDCCH) for receiving a random access response based on a second random access radio network temporary identifier (RA-RNTI), the second RA-RNTI being determined based on the first configuration information and the second configuration information or determined based on the first configuration information.

[0066] Optionally, the second RA-RNTI is determined based on random access resource related information of the first uplink resource, the random access resource related information being used to indicate whether the first uplink resource is related to a second feature.

[0067] Optionally, the method further comprises: receiving second downlink control information, the second downlink control information being used to indicate the first random access resource, the first uplink resource being determined based on the first configuration information and the second downlink control information.

[0068] Optionally, frequency resource indexes of the first random access resources are determined based on at least one of: a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources; a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources; the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources; the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; or the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0069] Optionally, the method further comprises: if first downlink control information is received in a second time window, monitoring a physical downlink control channel (PDCCH) for receiving a random access response based on a first random access radio network temporary identifier (RA-RNTI) in the second time window, wherein the first downlink control information is used to indicate the first random access resources, and the first RA-RNTI is determined based on the first uplink resource and the first downlink control information.

[0070] According to a further aspect of embodiments of the present disclosure, there is provided a method performed by a base station in a communication system, the method comprises: transmitting first information, the first information being used to indicate first random access resources; monitoring a preamble transmitted by a user equipment (UE), the preamble being transmitted on a first uplink resource, the first uplink resource being determined by the UE based on the first random access resources indicated by the first information; transmitting first downlink control information, the first downlink control information being used to indicate the first random access resources; and transmitting a physical downlink control channel (PDCCH) for transmitting a random access response based on a first random access radio network temporary identifier (RA-RNTI), the first RA-RNTI being determined based on the first uplink resource and the first downlink control information.

[0071] According to still another aspect of embodiments of the present disclosure, there is provided another method performed by a base station in a communication system, the method comprises: transmitting first information, the first information being used to indicate first random access resources; monitoring a preamble transmitted by a user equipment (UE), the preamble being transmitted on a first uplink resource, the first uplink resource being determined by the UE based on the first random access resources indicated by the first information; transmitting first downlink control information, the first downlink control information being used to indicate the first random access resources; and monitoring a preamble transmitted by the UE, the preamble being transmitted on a second uplink resource, the second uplink resource being determined based on the first downlink control information, received power of the preamble being related to a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information.

[0072] According to a further aspect of embodiments of the present disclosure, there is also provided yet another method performed by a base station in a communication system, the method comprises: transmitting first configuration information related to a first random access and second configuration information related to a second random access, wherein the first configuration information is related to a second feature; monitoring a preamble transmitted by a user equipment (UE), the preamble being transmitted on a first uplink resource, the first uplink resource being determined based on the first configuration information; and transmitting a physical downlink control channel (PDCCH) for transmitting a random access response based on a second random access radio network temporary identifier (RA-RNTI), the second RA-RNTI being determined based on the first configuration information and the second configuration information or determined based on the first configuration information.

[0073] According to a further aspect of embodiments of the present disclosure, there is provided a user equipment (UE) comprising: a transceiver; and a processor coupled with the transceiver and configured to perform the method performed by the UE in a communication system according to the embodiments of the present disclosure.

[0074] According to a further aspect of embodiments of the present disclosure, there is provided a base station comprising: a transceiver; and a processor coupled with the transceiver and configured to perform the method performed by the base station in a communication system according to the embodiments of the present disclosure.

[0075] According to yet another aspect of embodiments of the present disclosure, there is provided a computer-readable storage medium having stored thereon a computer program, that when executed by a processor, implements a method performed by a UE or a base station in a communication system according to the embodiments of the present disclosure.

[0076] According to a further aspect of embodiments of the present disclosure, there is provided a computer program product comprising a computer program, that when executed by a processor, implements a method performed by a UE or a base station in a communication system according to the embodiments of the present disclosure.

[0077] The communication method and user equipment provided by embodiments of the present disclosure can enhance the reliability of receiving a random access response and improve the random access performance by: receiving first information, the first information being used to indicate first random access resources; transmitting a preamble on a first uplink resource, the first uplink resource being determined based on the first random access resources indicated by the first information; and if first downlink control information is received in a second time window, monitoring a physical downlink control channel (PDCCH) for receiving a random access response based on a first random access radio network temporary identifier (RA-RNTI) in the second time window, wherein the first downlink control information is used to indicate the first random access resources, and the first RA-RNTI is determined based on the first uplink resource and the first downlink control information.

[0078] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

[0079] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

[0080] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0081] The term "include" or "may include" refers to the existence of a corresponding disclosed function, operation or component which can be used in various embodiments of the present disclosure and does not limit one or more additional functions, operations, or components. The terms such as "include" and / or "have" may be construed to denote a certain characteristic, number, step, operation, constituent element, component or a combination thereof, but may not be construed to exclude the existence of or a possibility of addition of one or more other characteristics, numbers, steps, operations, constituent elements, components or combinations thereof.

[0082] The term "or" used in various embodiments of the present disclosure includes any or all of combinations of listed words. For example, the expression "A or B" may include A, may include B, or may include both A and B.

[0083] Unless defined differently, all terms used herein, which include technical terminologies or scientific terminologies, have the same meaning as that understood by a person skilled in the art to which the present disclosure belongs. Such terms as those defined in a generally used dictionary are to be interpreted to have the meanings equal to the contextual meanings in the relevant field of art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined in the present disclosure.

[0084] The various embodiments of the present disclosure can be applied to various communication systems, such as: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, broadband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system Frequency division duplex (FDD) systems, time division duplex (TDD) systems, universal mobile telecommunications systems (UMTS), global interoperability for microwave access (WiMAX) communication systems, fifth generation (5G) systems or new wireless (NR) systems, etc. In addition, the various embodiments of the present disclosure can be applied to future oriented communication technologies.

[0085] In order to meet the increasing demand for wireless data communication services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "Beyond 4G networks" or "Post-LTE systems".

[0086] In order to achieve a higher data rate, 5G communication systems are implemented in higher frequency (millimeter, mmWave) bands, e.g., 60 GHz bands. In order to reduce propagation loss of radio waves and increase a transmission distance, technologies such as beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antenna, analog beamforming and large-scale antenna are discussed in 5G communication systems.

[0087] In addition, in 5G communication systems, developments of system network improvement are underway based on advanced small cell, cloud radio access network (RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, mobile network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation, etc.

[0088] In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM), and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies have been developed.

[0089] FIG. 1 illustrates an example wireless network 100 according to various embodiments of the present disclosure. The embodiment of the wireless network 100 shown in FIG. 1 is for illustration only. Other embodiments of the wireless network 100 can be used without departing from the scope of the present disclosure.

[0090] The wireless network 100 includes a gNodeB (gNB) 101, a gNB 102, and a gNB 103. gNB 101 communicates with gNB 102 and gNB 103. gNB 101 also communicates with at least one Internet Protocol (IP) network 130, such as the Internet, a private IP network, or other data networks.

[0091] Depending on a type of the network, other well-known terms such as "base station" or "access point" may be used instead of "gNodeB" or "gNB". For convenience, the terms "gNodeB" and "gNB" are used in this patent document to refer to network infrastructure components that provide wireless access for remote terminals. And, depending on the type of the network, other well-known terms such as "mobile station", "user station", "remote terminal", "wireless terminal" or "user apparatus" may be used instead of "user equipment" or "UE". For convenience, the terms "user equipment" and "UE" are used in this patent document to refer to remote wireless devices that wirelessly access the gNB, no matter whether the UE is a mobile device (such as a mobile phone or a smart phone) or a fixed device (such as a desktop computer or a vending machine).

[0092] gNB 102 provides wireless broadband access to the network 130 for a first plurality of User Equipments (UEs) within a coverage area 120 of gNB 102. The first plurality of UEs include a UE 111, which may be located in a Small Business (SB); a UE 112, which may be located in an enterprise (E); a UE 113, which may be located in a WiFi Hotspot (HS); a UE 114, which may be located in a first residence (R); a UE 115, which may be located in a second residence (R); a UE 116, which may be a mobile device (M), such as a cellular phone, a wireless laptop computer, a wireless PDA, etc. gNB 103 provides wireless broadband access to network 130 for a second plurality of UEs within a coverage area 125 of gNB 103. The second plurality of UEs include a UE 115 and a UE 116. In some embodiments, one or more of gNBs 101-103 may communicate with each other and with UEs 111-116 using 5G, Long Term Evolution (LTE), LTE-A, WiMAX or other advanced wireless communication technologies.

[0093] The dashed lines show approximate ranges of the coverage areas 120 and 125, and the ranges are shown as approximate circles merely for illustration and explanation purposes. It should be clearly understood that the coverage areas associated with the gNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending on configurations of the gNBs and changes in the radio environment associated with natural obstacles and man-made obstacles.

[0094] As will be described in more detail below, one or more of gNB 101, gNB 102, and gNB 103 include a 2D antenna array as described in embodiments of the present disclosure. In some embodiments, one or more of gNB 101, gNB 102, and gNB 103 support codebook designs and structures for systems with 2D antenna arrays.

[0095] Although FIG. 1 illustrates an example of the wireless network 100, various changes may be made to FIG. 1. The wireless network 100 may include any number of gNBs and any number of UEs in any suitable arrangement, for example. Furthermore, gNB 101 may directly communicate with any number of UEs and provide wireless broadband access to the network 130 for those UEs. Similarly, each gNB 102-103 may directly communicate with the network 130 and provide direct wireless broadband access to the network 130 for the UEs. In addition, gNB 101, 102 and / or 103 may provide access to other or additional external networks, such as external telephone networks or other types of data networks.

[0096] FIGs. 2a and 2b illustrate example wireless transmission and reception paths according to the present disclosure. In the following description, the transmission path 200 may be described as being implemented in a gNB, such as gNB 102, and the reception path 250 may be described as being implemented in a UE, such as UE 116. However, it should be understood that the reception path 250 may be implemented in a gNB and the transmission path 200 may be implemented in a UE. In some embodiments, the reception path 250 is configured to support codebook designs and structures for systems with 2D antenna arrays as described in embodiments of the present disclosure.

[0097] The transmission path 200 includes a channel coding and modulation block 205, a Serial-to-Parallel (S-to-P) block 210, a size N Inverse Fast Fourier Transform (IFFT) block 215, a Parallel-to-Serial (P-to-S) block 220, a cyclic prefix addition block 225, and an up-converter (UC) 230. The reception path 250 includes a down-converter (DC) 255, a cyclic prefix removal block 260, a Serial-to-Parallel (S-to-P) block 265, a size N Fast Fourier Transform (FFT) block 270, a Parallel-to-Serial (P-to-S) block 275, and a channel decoding and demodulation block 280.

[0098] In the transmission path 200, the channel coding and modulation block 205 receives a set of information bits, applies coding (such as Low Density Parity Check (LDPC) coding), and modulates the input bits (such as using Quadrature Phase Shift Keying (QPSK) or Quadrature Amplitude Modulation (QAM)) to generate a sequence of frequency-domain modulated symbols. The Serial-to-Parallel (S-to-P) block 210 converts (such as demultiplexes) serial modulated symbols into parallel data to generate N parallel symbol streams, where N is a size of the IFFT / FFT used in gNB 102 and UE 116. The size N IFFT block 215 performs IFFT operations on the N parallel symbol streams to generate a time-domain output signal. The Parallel-to-Serial block 220 converts (such as multiplexes) parallel time-domain output symbols from the Size N IFFT block 215 to generate a serial time-domain signal. The cyclic prefix addition block 225 inserts a cyclic prefix into the time-domain signal. The up-converter 230 modulates (such as up-converts) the output of the cyclic prefix addition block 225 to an RF frequency for transmission via a wireless channel. The signal may also be filtered at a baseband before switching to the RF frequency.

[0099] The RF signal transmitted from gNB 102 arrives at UE 116 after passing through the wireless channel, and operations in reverse to those at gNB 102 are performed at UE 116. The down-converter 255 down-converts the received signal to a baseband frequency, and the cyclic prefix removal block 260 removes the cyclic prefix to generate a serial time-domain baseband signal. The Serial-to-Parallel block 265 converts the time-domain baseband signal into a parallel time-domain signal. The Size N FFT block 270 performs an FFT algorithm to generate N parallel frequency-domain signals. The Parallel-to-Serial block 275 converts the parallel frequency-domain signal into a sequence of modulated data symbols. The channel decoding and demodulation block 280 demodulates and decodes the modulated symbols to recover the original input data stream.

[0100] Each of gNBs 101-103 may implement a transmission path 200 similar to that for transmitting to UEs 111-116 in the downlink, and may implement a reception path 250 similar to that for receiving from UEs 111-116 in the uplink. Similarly, each of UEs 111-116 may implement a transmission path 200 for transmitting to gNBs 101-103 in the uplink, and may implement a reception path 250 for receiving from gNBs 101-103 in the downlink.

[0101] Each of the components in FIGs. 2a and 2b may be implemented using only hardware, or using a combination of hardware and software / firmware. As a specific example, at least some of the components in FIGs. 2a and 2b may be implemented in software, while other components may be implemented in configurable hardware or a combination of software and configurable hardware. For example, the FFT block 270 and IFFT block 215 may be implemented as configurable software algorithms, in which the value of the size N may be modified according to the implementation.

[0102] Furthermore, although described as using FFT and IFFT, this is only illustrative and should not be interpreted as limiting the scope of the present disclosure. Other types of transforms may be used, such as Discrete Fourier transform (DFT) and Inverse Discrete Fourier Transform (IDFT) functions. It should be understood that for DFT and IDFT functions, the value of variable N may be any integer (such as 1, 2, 3, 4, etc.), while for FFT and IFFT functions, the value of variable N may be any integer which is a power of 2 (such as 1, 2, 4, 8, 16, etc.).

[0103] Although FIGs. 2a and 2b illustrate examples of wireless transmission and reception paths, various changes may be made to FIGs. 2a and 2b. For example, various components in FIGs. 2a and 2b may be combined, further subdivided or omitted, and additional components may be added according to specific requirements. Furthermore, FIGs. 2a and 2b are intended to illustrate examples of types of transmission and reception paths that may be used in a wireless network. Any other suitable architecture may be used to support wireless communication in a wireless network.

[0104] FIG. 3a illustrates an example UE 116 according to the present disclosure. The embodiment of UE 116 shown in FIG. 3a is for illustration only, and UEs 111-115 of FIG. 1 may have the same or similar configuration. However, a UE has various configurations, and FIG. 3a does not limit the scope of the present disclosure to any specific implementation of the UE.

[0105] UE 116 includes an antenna 301, a radio frequency (RF) transceiver 302, a transmission (TX) processing circuit 303, a microphone 304, and a reception (RX) processing circuit 305. UE 116 also includes a speaker 306, a controller / processor 307, an input / output (I / O) interface 308, an input device(s) 309, a display 310, and a memory 311. The memory 311 includes an operating system (OS) 312 and one or more applications 313.

[0106] The RF transceiver 302 receives an incoming RF signal transmitted by a gNB of the wireless network 100 from the antenna 301. The RF transceiver 302 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is transmitted to the RX processing circuit 305, where the RX processing circuit 305 generates a processed baseband signal by filtering, decoding and / or digitizing the baseband or IF signal. The RX processing circuit 305 transmits the processed baseband signal to speaker 306 (such as for voice data) or to controller / processor 307 for further processing (such as for web browsing data).

[0107] The TX processing circuit 303 receives analog or digital voice data from microphone 304 or other outgoing baseband data (such as network data, email or interactive video game data) from controller / processor 307. The TX processing circuit 303 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 302 receives the outgoing processed baseband or IF signal from the TX processing circuit 303 and up-converts the baseband or IF signal into an RF signal transmitted via the antenna 301.

[0108] The controller / processor 307 may include one or more processors or other processing devices and execute an OS 312 stored in the memory 311 in order to control the overall operation of UE 116. For example, the controller / processor 307 may control the reception of forward channel signals and the transmission of backward channel signals through the RF transceiver 302, the RX processing circuit 305 and the TX processing circuit 303 according to well-known principles. In some embodiments, the controller / processor 307 includes at least one microprocessor or microcontroller.

[0109] The controller / processor 307 is also capable of executing other processes and programs residing in the memory 311, such as operations for channel quality measurement and reporting for systems with 2D antenna arrays as described in embodiments of the present disclosure. The controller / processor 307 may move data into or out of the memory 311 as required by an execution process. In some embodiments, the controller / processor 307 is configured to execute the application 313 based on the OS 312 or in response to signals received from the gNB or the operator. The controller / processor 307 is also coupled to an I / O interface 308, where the I / O interface 308 provides UE 116 with the ability to connect to other devices such as laptop computers and handheld computers. I / O interface 308 is a communication path between these accessories and the controller / processor 307.

[0110] The controller / processor 307 is also coupled to the input device(s) 309 and the display 310. An operator of UE 116 may input data into UE 116 using the input device(s) 309. The display 310 may be a liquid crystal display or other display capable of presenting text and / or at least limited graphics (such as from a website). The memory 311 is coupled to the controller / processor 307. A part of the memory 311 may include a random access memory (RAM), while another part of the memory 311 may include a flash memory or other read-only memory (ROM).

[0111] Although FIG. 3a illustrates an example of UE 116, various changes may be made to FIG. 3a. For example, various components in FIG. 3a may be combined, further subdivided or omitted, and additional components may be added according to specific requirements. As a specific example, the controller / processor 307 may be divided into a plurality of processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Furthermore, although FIG. 3a illustrates that the UE 116 is configured as a mobile phone or a smart phone, UEs may be configured to operate as other types of mobile or fixed devices.

[0112] FIG. 3b illustrates an example gNB 102 according to the present disclosure. The embodiment of gNB 102 shown in FIG. 3b is for illustration only, and other gNBs of FIG. 1 may have the same or similar configuration. However, a gNB has various configurations, and FIG. 3b does not limit the scope of the present disclosure to any specific implementation of a gNB. It should be noted that gNB 101 and gNB 103 may include the same or similar structures as gNB 102.

[0113] As shown in FIG. 3b, gNB 102 includes a plurality of antennas 370a-370n, a plurality of RF transceivers 372a-372n, a transmission (TX) processing circuit 374, and a reception (RX) processing circuit 376. In certain embodiments, one or more of the plurality of antennas 370a-370n include a 2D antenna array. gNB 102 also includes a controller / processor 378, a memory 380, and a backhaul or network interface 382.

[0114] RF transceivers 372a-372n receive an incoming RF signal from antennas 370a-370n, such as a signal transmitted by UEs or other gNBs. RF transceivers 372a-372n down-convert the incoming RF signal to generate an IF or baseband signal. The IF or baseband signal is transmitted to the RX processing circuit 376, where the RX processing circuit 376 generates a processed baseband signal by filtering, decoding and / or digitizing the baseband or IF signal. RX processing circuit 376 transmits the processed baseband signal to controller / processor 378 for further processing.

[0115] The TX processing circuit 374 receives analog or digital data (such as voice data, network data, email or interactive video game data) from the controller / processor 378. TX processing circuit 374 encodes, multiplexes and / or digitizes outgoing baseband data to generate a processed baseband or IF signal. RF transceivers 372a-372n receive the outgoing processed baseband or IF signal from TX processing circuit 374 and up-convert the baseband or IF signal into an RF signal transmitted via antennas 370a-370n.

[0116] The controller / processor 378 may include one or more processors or other processing devices that control the overall operation of gNB 102. For example, the controller / processor 378 may control the reception of forward channel signals and the transmission of backward channel signals through the RF transceivers 372a-372n, the RX processing circuit 376 and the TX processing circuit 374 according to well-known principles. The controller / processor 378 may also support additional functions, such as higher-level wireless communication functions. For example, the controller / processor 378 may perform a Blind Interference Sensing (BIS) process such as that performed through a BIS algorithm, and decode a received signal from which an interference signal is subtracted. A controller / processor 378 may support any of a variety of other functions in gNB 102. In some embodiments, the controller / processor 378 includes at least one microprocessor or microcontroller.

[0117] The controller / processor 378 is also capable of executing programs and other processes residing in the memory 380, such as a basic OS. The controller / processor 378 may also support channel quality measurement and reporting for systems with 2D antenna arrays as described in embodiments of the present disclosure. In some embodiments, the controller / processor 378 supports communication between entities such as web RTCs. The controller / processor 378 may move data into or out of the memory 380 as required by an execution process.

[0118] The controller / processor 378 is also coupled to the backhaul or network interface 382. The backhaul or network interface 382 allows gNB 102 to communicate with other devices or systems through a backhaul connection or through a network. The backhaul or network interface 382 may support communication over any suitable wired or wireless connection(s). For example, when gNB 102 is implemented as a part of a cellular communication system, such as a cellular communication system supporting 5G or new radio access technology or NR, LTE or LTE-A, the backhaul or network interface 382 may allow gNB 102 to communicate with other gNBs through wired or wireless backhaul connections. When gNB 102 is implemented as an access point, the backhaul or network interface 382 may allow gNB 102 to communicate with a larger network, such as the Internet, through a wired or wireless local area network or through a wired or wireless connection. The backhaul or network interface 382 includes any suitable structure that supports communication through a wired or wireless connection, such as an Ethernet or an RF transceiver.

[0119] The memory 380 is coupled to the controller / processor 378. A part of the memory 380 may include an RAM, while another part of the memory 380 may include a flash memory or other ROMs. In certain embodiments, a plurality of instructions, such as the BIS algorithm, are stored in the memory. The plurality of instructions are configured to cause the controller / processor 378 to execute the BIS process and decode the received signal after subtracting at least one interference signal determined by the BIS algorithm.

[0120] As will be described in more detail below, the transmission and reception paths of gNB 102 (implemented using RF transceivers 372a-372n, TX processing circuit 374 and / or RX processing circuit 376) support aggregated communication with FDD cells and TDD cells.

[0121] Although FIG. 3b illustrates an example of gNB 102, various changes may be made to FIG. 3b. For example, gNB 102 may include any number of each component shown in FIG. 3a. As a specific example, the access point may include many backhaul or network interfaces 382, and the controller / processor 378 may support routing functions to route data between different network addresses. As another specific example, although shown as including a single instance of the TX processing circuit 374 and a single instance of the RX processing circuit 376, gNB 102 may include multiple instances of each (such as one for each RF transceiver).

[0122] A time domain unit (also referred to as a time unit) in the embodiments of the present disclosure may be: an orthogonal frequency division multiplexing (OFDM) symbol, a group of OFDM symbols (comprising a plurality of OFDM symbols), a slot, a group of slots (comprising a plurality of slots), a subframe, a group of subframes (comprising a plurality of subframes), a system frame, or a group of system frames (comprising a plurality of system frames), or it may also be an absolute time unit, such as 1 millisecond, 1 second, etc. The time unit may also be a combination of multiple granularities, for example, Ns slots plus No OFDM symbols, etc. It may also be a duration of time for an on-off keying (OOK) code.

[0123] A frequency domain unit (also referred to as a frequency unit) in the embodiments of the present disclosure may be: a subcarrier, a group of subcarriers (comprising a plurality of subcarriers), a resource block (RB), which may also be referred to as a physical resource block (PRB), a group of resource blocks (comprising a plurality of RBs), a bandwidth part (BWP), a group of bandwidth parts (comprising a plurality of BWPs), a frequency band / carrier, or a frequency band group / carrier group, and it may also be an absolute frequency domain unit, such as 1 Hz, 1 kHz, etc. The frequency domain unit may also be a combination of multiple granularities, such as M1 PRBs plus M2 subcarriers, etc.

[0124] Exemplary embodiments of the present disclosure are further described below in conjunction with the accompanying drawings.

[0125] Text and drawings are provided as examples only to assist the reader in understanding the present disclosure. They are not intended to and should not be construed as limiting the scope of the present disclosure in any way. Although certain embodiments and examples have been provided, based on the disclosure herein, it is apparent to those skilled in the art that changes may be made to the shown embodiments and examples without departing from the scope of the present disclosure.

[0126] In a wireless communication system, a transmission link mainly comprises a downlink communication link from a 5G gNB to a UE, and an uplink communication link from the UE to a network. The nodes for location measurement in the wireless communication system, for example in the current wireless communication system, include: a UE that initiates a location request message, a location management function (LMF) for UE localization and localization assistance data distribution, a gNB or transmission-reception point (TRP) that broadcasts the localization assistance data and performs uplink location measurement, or a UE for downlink location measurement.

[0127] In addition, a scheme provided by the embodiments of the present disclosure may be extended to be applied in other communication systems, such as vehicle-to-X (V2X), e.g., sidelink communication, where the transmission-reception point (TRP) or the UE may be any kind of device in a V2X system.

[0128] In the wireless communication system, for transmission from a base station (e.g., gNB) to a UE, the corresponding slot is referred to as a downlink slot, and for transmission from the UE to the base station (e.g., gNB), the corresponding slot is referred to as an uplink slot.

[0129] In the wireless communication system, such as an LTE or NR system, a 2-step or 4-step random access procedure may be used to establish a link between the device and the base station. The base station transmits a synchronization signal and a broadcast channel to the UE periodically through a synchronization signal block (SSB / physical broadcast channel (PBCH), or referred to as a downlink reference signal), and the periodicity is a synchronization signal block periodicity (e.g. SSB periodicity), or is referred to as a synchronization signal block burst periodicity (SSB burst periodicity). Meantime, the base station will configure a physical random access channel configuration period (PRACH configuration period), in which a certain number of random access transmission occasions (also referred to as random access occasions, PRACH transmission occasions, ROs) are configured. It may also be understood that the base station will configure the physical random access channel (PRACH) through broadcast messages for random access by the UE.

[0130] In addition, in a NR communication system, before the radio resource control is established, e.g., in the random access procedure, the performance of random access directly affects the user experience. In conventional wireless communication systems such as LTE and LTE-Advanced, or in 5G or NR systems, the random access procedure is applied in multiple scenarios such as initial link establishment, cell handover, uplink re-establishment, and radio resource control (RRC) connection re-establishment, etc., and is categorized into contention-based random access and contention-free random access, depending on whether the UE has preamble resources exclusively. In contention-based random access, each user selects a preamble sequence to be transmitted to the base station from the same preamble sequence resources, in the process of attempting to establish an uplink.

[0131] As random access is an important research direction in a communication system, how to improve the performance of random access for users is a problem to be urgently solved. A random access method provided by the embodiment of the present disclosure may enhance the reliability of receiving a random access response, and improve the performance of random access.

[0132] It should be noted that the problems that may be solved by the present disclosure are not limited to the problems mentioned in the above and following descriptions, but may also solve all problems that may be actually solved according to the technical substance of the present disclosure.

[0133] The technical solutions of the embodiments of the present disclosure and the technical effects produced by the technical solutions of the present disclosure are described below by describing several exemplary implementations. It should be noted that the following embodiments may be referred to, learned from, or combined with each other, and the same terms, similar features, and similar implementation steps in different embodiments will not be described repeatedly.

[0134] An embodiment of the present disclosure provides a method performed by a UE in a communication system. As shown in FIG. 4, the method comprises S410, S420, S430, etc. It should be noted that at least one of the above operations may be omitted, or, alternatively, additional operations may be included, e.g., one or more operations of the method described according to the embodiment of the present disclosure.

[0135] In step S410, the UE receives first information, the first information being used to indicate first random access resources.

[0136] In the embodiment of the present disclosure, for convenience of description, random access associated with a particular feature (e.g., network energy saving (NES)) (e.g., random access resources may be used for the random access as well as for the particular feature) may be referred to as "Type-1 random access" or simply "first random access", and resources configured for the first random access are referred to as a "first random access resources", or simply "Type-1 random occasions (ROs)", or "first ROs", or "first PRACH occasions", etc. Conventional random access may be referred to as "normal random access" or "second random access", and resources respective to the second random access is referred to as "normal random access resources" or "normal ROs" or "second random access resources", or may be simply referred to as "Type-2 ROs", or "second ROs", or "second PRACH occasions", etc.

[0137] In the embodiment of the present disclosure, without changing the second random access resources, the random access resources may be additionally configured for other features (e.g., network energy saving, NES feature), such as the first random access resources, and the random access is performed in the case that the random access resources are configured for the other features (e.g., NES), to improve the performance of random access.

[0138] The base station may adjust the first random access resources configured in the network and indicated by the first information to realize the NES. Optionally, the first random access resources indicated by the first information are activated and / or deactivated.

[0139] In step S420, the UE transmits a preamble on a first uplink resource, the first uplink resource is determined based on the first random access resources indicated by the first information.

[0140] In the embodiment of the present disclosure, the UE may select one of the first random access resources indicated by the first information as the first uplink resource on which to transmit the preamble (also interchangeably referred to as a "preamble sequence" or a "lead code").

[0141] In step S430, if first downlink control information is received in a second time window, the UE monitors a physical downlink control channel (PDCCH) for receiving a random access response (RAR) based on a first random access radio network temporary identifier (RA-RNTI) in the second time window, wherein the first downlink control information is used to indicate the first random access resources, and the first RA-RNTI is determined based on the first uplink resource and the first downlink control information.

[0142] In the embodiment of the present disclosure, the UE may start the second time window after transmitting the preamble, and then in the second time window, the UE attempts to receive the random access response. The second time window may also be understood as a RAR detection window.

[0143] Optionally, the second time window may be obtained by random access related configuration information.

[0144] In the embodiment of the present disclosure, during running of the second time window, the UE receives the first downlink control information used to indicate the first random access resources. In order to avoid a conflict in RA-RNTI values respective to before and after the reception based on the first downlink control information due to a change in the first random access resources indicated by the first downlink control information and / or frequency resource indexes thereof (which may also be referred to as frequency resource indexes), the UE may receive the random access response based on the first RA-RNTI, where the first RA-RNTI is determined based on the first uplink resource and the first downlink control information, which is different from the second RA-RNTI determined based on the first uplink resource. This solves the problem of the UE incorrectly decoding the random access response due to RA-RNTI conflict, lowers the conflicting probability of random access, and improves the reliability of random access.

[0145] In addition, the random access method provided by the embodiment of the present disclosure may adaptively configure PRACH resources in accordance with energy-saving requirements, reduce energy consumption of the base station for detecting the PRACH without affecting the random access performance of the UE, and assist with implementation of the NES.

[0146] More details are provided in the embodiment of the present disclosure of a method for random access in a system in which random access resources, such as random access configuration, random access resource determination, SSB-to-RO mapping (SSB-RO), etc., are configured for the other features (e.g., NES).

[0147] It should be noted that the PRACH may be described in the present disclosure as an uplink channel related to the random access, but this is only exemplary, and the PRACH may also be replaced with other uplink channels such as physical uplink shared channel (PUSCH), physical uplink control channel (PUCCH), etc.

[0148] In the embodiment of the present disclosure, the configuration information, if not specifically specified, comprises at least one of information configured by the base station, information indicated in the received signaling, information configured through a higher layer, and pre-configured information. Further, it may be a set of configuration information obtained by the above method or a plurality of sets of configuration information obtained by the above method, from which the UE or the node may select a set of configuration information for use according to predefined conditions, or it may be a set of configuration information obtained by the above method and the set of configuration information comprises a plurality of subsets, from which the UE or the node may select a subset for use according to the predefined conditions.

[0149] In the embodiment of the present disclosure, the first information and / or the first downlink control information may comprise at least one of the followings.

[0150] (1) Information about whether the first random access resources are all activated;

[0151] Information about whether the first random access resources are all activated may also be referred to as indication information related to whether the first random access resources are activated, e.g., if the first random access resources are configured, the first random access resources are activated; otherwise, the first random access resources are not activated or deactivated.

[0152] (2) Information that at least one of the first random access resources is activated or deactivated;

[0153] Information that at least one of the first random access resources is activated or deactivated may also be referred to as indication information related to activation or deactivation of the first random access resources, which is used for determining the first random access resources that are activated or deactivated among the configured first random access resources.

[0154] For example, in order to indicate the first random access resources that are activated or deactivated among the configured first random access resources, a method for indication may be by way of a bit map, for example, {0,1,1} indicates that the first random access resource with an index of 0 is deactivated or not activated, and that the first random access resources with indexes of 1 and 2 are activated, where the indexes may be a time-domain index, or a frequency resource index, or a time-and-frequency domain common index.

[0155] In the embodiment of the present disclosure, the first information and / or the first downlink control information (e.g., for a case where information that at least one of the first random access resources is activated or deactivated is included) comprises at least one of the followings.

[0156] (1) Mask information for mapping of synchronization signal blocks (SSBs) to the activated first random access resources;

[0157] for example, a PRACH mask that indicates the first random access resources associated with one or more SSB indexes which are activated or deactivated among the first random access resources, for example the PRACH mask may be used to indicate that all of the first random access resources are available, or that even-numbered first random access resources are available, or that odd-numbered first random access resources are available, or that the first random access resource with a number of x is available (where a range of the number x is determined based on a frequency resource index range of the first random access resources, and may be for example from 0 to M1-1, where M1 is a number of the first random access resources used for frequency division multiplexing (FDM) for the first random access).

[0158] (2) A period index for mapping of SSBs to the activated first random access resources;

[0159] A period index for mapping of SSBs to the activated first random access resources may indicate the first random access resources that are activated or deactivated among the first random access resources within a certain time period, such as SSB-first RO mapping periods or SSB-first RO mapping period indexes, etc., for indicating one or more SSB-first RO mapping periods, where the first random access resources included therein are activated or deactivated, e.g., the index 0 or 1 may indicate that the first random access resources within the first SSB-first RO mapping period are activated or deactivated.

[0160] (3) A PRACH association period index;

[0161] A PRACH association period index may also indicate the first random access resources that are activated or deactivated among the first random access resources within a certain time period, e.g., to indicate one or more PRACH association periods (SSB-Type-1 RO association period indexes), where the first random access resources included therein are activated or deactivated, e.g., the index 0 or 1 may indicate that the first random access resources within the first PRACH association period are activated or deactivated.

[0162] (4) A PRACH association pattern period index;

[0163] A PRACH association pattern period index may also indicate the first random access resources that are activated or deactivated among the first random access resources within a certain time period, e.g., to indicate one or more PRACH association pattern periods (SSB-Type-1 RO association pattern periods), wherein the first random access resources included therein are activated or deactivated, e.g., the index 0 or 1 may indicate that the first random access resources within the first PRACH association pattern period are activated or deactivated.

[0164] (5) At least one fourth RA-RNTI;

[0165] In the embodiment of the present disclosure, the fourth RA-RNTI may also be understood as a dedicated RA-RNTI, which may be used to determine the activated first random access resources by indicating one or more dedicated RA-RNTIs; optionally, the dedicated RA-RNTIs may be obtained by a formula for calculating the RA-RNTIs based on a protocol.

[0166] (6) A reference fourth RA-RNTI and a number of the fourth RA-RNTIs;

[0167] In the embodiment of the present disclosure, the reference fourth RA-RNTI which may also be referred to simply as a reference RA-RNTI, and a first quantity which is used to indicate the number of the fourth RA-RNTIs may also be indicated, wherein the first quantity of fourth RA-RNTIs may be consecutive fourth RA-RNTIs, wherein a starting one of the consecutive fourth RA-RNTIs is the reference fourth RA-RNTI, and an ending one is at (the reference fourth RA-RNTI + the first quantity - 1); for example, if the reference fourth RA-RNTI is 1000 and the first quantity is 3, the indicated fourth RA-RNTIs are {1000, 1001, 1002}.

[0168] A beneficial effect of the method of utilizing the fourth RA-RNTIs to indicate the activated first random access resources is that, since the fourth RA-RNTIs are determined based on time-and-frequency domain resources of the random access resources, given a fourth RA-RNTI, the UE may uniquely determine a random access resource, and the way to indicate that the first random access resources are activated or deactivated by the RA-RNTI is simple, easy to implement, and involves a small change to the protocol.

[0169] (7) A time unit index;

[0170] A time unit index may also indicate the first random access resources that are activated or deactivated among the first random access resources within a certain time period.

[0171] Optionally, the time unit index may indicate a system frame number (SFN, which may also be referred to as a radio frame number) of the activated first random access resources, for indicating one or more radio frames, where the first random access resources included therein are activated or deactivated, e.g., the SFN 0 may indicate that the first random access resources in the first radio frame are activated or deactivated.

[0172] Optionally, the time unit index may indicate a slot index of the activated first random access resources, for indicating one or more slots, where the first random access resources included therein are activated or deactivated.

[0173] Optionally, the time unit index may indicate a symbol index of the activated first random access resources, for indicating one or more symbols, where the first random access resources included therein are activated or deactivated.

[0174] (8) A frequency unit index;

[0175] A frequency unit index may indicate the first random access resources that are activated or deactivated among the first random access resources within a certain frequency-domain range. For example, the frequency unit index may indicate a bandwidth part (BWP) index, a subcarrier index, a physical resource block (PRB) index, etc., of the activated first random access resources, for indicating that the corresponding first random access resources are activated or deactivated.

[0176] In the embodiment of the present disclosure, the first information comprises random access related configuration information and / or downlink control information.

[0177] In an optional implementation, the random access-related configuration information includes a combination of one or more of:

[0178] (1) random access resource time domain-related configuration information, comprising a combination of one or more of:

[0179] 1. time domain-related configuration information of the first random access resources, comprising a combination of one or more of:

[0180] 1) a random access configuration (e.g., PRACH configuration) index for the first random access (e.g., a higher layer parameter PRACH-ConfigurationIndex, according to which a random access preamble format, a random access configuration period (which may also be referred to as the first random access period), the number and locations of random access frames in the random access configuration period, indexes of subframes or slots in a random access frame, a starting symbol location of a random access preamble in a subframe or slot, a number of random access slots in a random access subframe, a number of ROs in a random access slot, a number of OFDM symbols occupied in a RO, etc.);

[0181] 2) an SSB-first RO (SSB to first random access resource mapping) association period; or

[0182] 3) an SSB-first RO association pattern period;

[0183] 2. time-domain related configuration information of the second random access resources, such as a random access configuration index, an SSB-second RO (SSB to second random access resource mapping) mapping period, an SSB-second RO association period; an SSB-second RO association pattern period, etc.; wherein the time-domain related configuration information of the second random access resources may be different from the time-domain related configuration information of the first random access resources, for example, the random access configuration index is not equal to the random access configuration index in the time-domain related configuration information of the first random access resources;

[0184] (2) random access resource frequency domain-related configuration information, comprising a combination of one or more of:

[0185] 1. a number of frequency division multiplexing (FDM) ROs (which may be referred to as a total number of ROs, or the number of random access resource frequency domain resources, e.g., a higher layer parameter msg1-FDMTotal), which is the number of frequency domain ROs on a random access time unit, including the first ROs and the second ROs;

[0186] 2. frequency domain-related configuration information of the first random access resources, comprising a combination of one or more of:

[0187] 1) a random access preamble root sequence index for the first random access;

[0188] 2) a number of random access preambles for the first random access, e.g., a number of preambles for the first random access on one first RO;

[0189] 3) a number of the first ROs for frequency division multiplexing (FDM) for the first random access (which may be referred to as e.g., a higher layer parameter msg1-FDM2, or referred to as the number of frequency domain resources of the first random access resources);

[0190] 4) a frequency start (location) of the first ROs for the first random access (e.g., a higher layer parameter msg1-FrequencyStart2, or be referred to as a frequency start offset of the first ROs) for determining an offset of the lowest first RO in the frequency domain, respective to PRB 0, respectively. The frequency start location of the first ROs is configured so that the corresponding first RO is entirely within the bandwidth of an uplink bandwidth part (UL BWP). The frequency start location of the first ROs also refers to a frequency start location of 1st first RO, and the ROs at other frequency domain locations are obtained by inference based on the location of the 1st first RO and a size of frequency domain resources occupied by one RO, and / or a frequency-domain spacing between the ROs;

[0191] 5) a frequency offset of the first ROs for the first random access, which is a frequency offset relative to the frequency start of the second ROs and may be one or more frequency domain units;

[0192] 3. frequency-domain related configuration information of the second random access resources, including a number of the second ROs for frequency division multiplexing (FDM) (e.g., a higher layer parameter msg1-FDM, or referred to as the number of frequency domain resources of the second random access resources); a frequency start (location) of the second ROs (or, referred to as the frequency start offset of the second ROs, e.g., a higher layer parameter msg1- FrequencyStart), for determining an offset of the lowest second RO in the frequency domain, respective to PRB 0, respectively;

[0193] (3) configuration information related to first random access power, including at least one of: a preamble target received power for the first random access; a pathloss compensation factor alpha (e.g., alpha x pathloss, when the alpha is less than 1, it indicates that partial pathloss compensation is carried out; when alpha=1, it indicates that full pathloss compensation is carried out; and when alpha>1, it indicates excess pathloss compensation, this configuration is beneficial for the UE to additionally obtain a power increase for preamble transmissions on the first ROs when using the normal preamble target received power); a difference in power increase (e.g., a delta value) for the first random access; a power ramping priority and / or a power step for the first random access; and a number threshold associated with the first ROs, etc., where the number threshold is used to determine a value of the power step.

[0194] Optionally, when the UE uses the first ROs for preamble transmission, the above-described first RO-specific power related configuration is used, and the transmission power P is determined in accordance with one or more of the target received power P0, the alpha Х pathloss, the delta, or the power ramping step Х number of retransmissions;

[0195] (4) First Information;

[0196] The first Information may also be referred to as configuration information related to activation or deactivation of the first random access resources, and for example may include the above-described indication information related to whether the first random access resources are activated and / or the above-described indication information related to activation or deactivation of the first random access resources;

[0197] (5) Indication information about whether only the activated first random access resources (which may be referred to as the activated first ROs) may be used;

[0198] (6) Indication information about whether the activated first random access resources (which may be referred to as the activated first ROs) are to be used first;

[0199] (7) A ratio of SSB to first RO mapping (SSB-first RO) (e.g., information indicating how many SSBs are mapped on the one first RO, see e.g. a higher layer parameter ssb-perRO);

[0200] (8) A second time window, the unit of which may be a plurality of time units (e.g., slots);

[0201] (9) A threshold for the number of preambles to be transmitted, whereby the UE selects to transmit the preambles on the second random access resources when the number of preambles transmitted on the first random access resources exceeds the threshold.

[0202] Optionally, the random access-related configuration information may be divided into first configuration information related to the first random access and second configuration information related to the second random access based on a relationship with the random access resource type. For example, a combination of one or more of the above may include the first configuration information and the second configuration information, and specific information shall be subject to the actual content, and will not be repeated herein in the embodiment of the present disclosure.

[0203] In an embodiment of the present disclosure, the UE may receive the random access-related configuration information by way of at least one of:

[0204] (1) a PDCCH command, such as a downlink control indicator (DCI);

[0205] (2) a medium access control (MAC) control element (CE); or

[0206] (3) a RRC higher layer signaling.

[0207] In the embodiment of the present disclosure, the first information may also be the downlink control information (in order to differentiate from the first downlink control information described above, it will be referred to hereinafter as second downlink control information), and the content of the second downlink control information may be found in the introduction of the first information above, which will not be repeated herein.

[0208] Optionally, the second downlink control information may be obtained by at least one of: a PDCCH (e.g., DCI), a MAC CE, a RRC higher layer signaling, etc.

[0209] It may be understood that the first downlink control information may be similar to the second downlink control information, and may be the downlink control information having the same format and type, i.e., both contain the same fields, the relevant contents and processing of which may be found in the introduction of the second downlink control information, and will not be repeated.

[0210] In the embodiment of the present disclosure, the first downlink control information / second downlink control information may be used for a first type of UE, and the random access-related configuration information may be used for the first type of UE and a second type of UE. For example, the first type of UE may be a UE that supports the NES feature, or the first type of UE may be a UE of the first release (e.g., the first release is not lower than release 19 or referred to as Rel 19), and the second type of UE may be a UE that does not support the NES feature, or the second type of UE may be a UE of the second release (e.g., not the first release).

[0211] In the embodiment of the present disclosure, a physical downlink control channel including the first information and / or a physical downlink control channel including the first downlink control information may be transmitted in a first search space (set), where the first search space includes at least one of:

[0212] (1) a common search space, such as a Type0 PDCCH CSS or a Type1 PDCCH CSS;

[0213] (2) a UE-specific search space; or

[0214] (3) a search space specific to receiving information for activating or deactivating the first random access resources.

[0215] Optionally, the format of the first downlink control information may be, for example, formats 1_0, 1_1, 2_7, 2_9, etc., or a format dedicated for activation or deactivation of the downlink control information.

[0216] Optionally, the first downlink control information may be scrambled based on a fifth RNTI when the first search space (set) is the UE-specific search space, or the search space dedicated for receiving information for activating or deactivating the first random access resources, where the fifth RNTI may be a cell-radio network temporary identity (C-RNTI) or a temporary cell-RNTI (TC-RNTI).

[0217] Optionally, when the first search space (set) is a common search space, the fifth RNTI may also be at least one of: a Paging-RNTI (P-RNTI); a system information-RNTI (SI-RNTI); a cell discontinuous transmission and reception-RNTI (CellDTRX-RNTI); or a paging early indication-RNTI (PEI-RNTI).

[0218] Optionally, for a case where the first search space comprises the search space dedicated for receiving information for activating or deactivating the first random access resources, the first search space may be scrambled according to an RNTI related to the NES feature.

[0219] In some implementations, when the first search space (set) is the search space dedicated for receiving a search space for activating or deactivating the first random access resources, the fifth RNTI may also be an RNTI specific to a second feature which may be, for example, the NES feature, but is not limited to thereto, and the RNTI specific to the second feature may be preset by the protocol or configured via the RRC higher layer signaling.

[0220] It should be noted that the first downlink control information is scrambled by the fifth RNTI, it specifically means that a cyclic redundancy check (CRC) of the PDCCH transmitting the DCI is scrambled based on the fifth RNTI.

[0221] In the embodiment of the present disclosure, the activated first random access resources may be determined based on the random access-related configuration information, or may be determined based on the random access configuration information and the downlink control information (e.g., the second downlink control information or the first downlink control information).

[0222] In the embodiment of the present disclosure, the method of determining the activated first random access resource based on the random access-related configuration information may be determined based on the time domain-related information and frequency domain-related information of the first random access resources included in the random access-related configuration information, as well as the first information (e.g., the configuration information related to activation or deactivation of the first random access resources).

[0223] In the embodiment of the present disclosure, the method of determining the activated first random access resource based on the random access-related configuration information may be determined based on the time domain-related information and frequency domain-related information of the first random access resources included in the random access-related configuration information, as well as the first information (e.g., the indication information related to whether the first random access resources are activated) included in the downlink control information (e.g., the second downlink control information).

[0224] In the embodiment of the present disclosure, the method of determining the activated first random access resources based on the random access-related configuration information may also be determined based on the time domain-related information and frequency domain-related information of the first random access resources included in the random access-related configuration information, as well as the first information (e.g., the indication information related to whether the first random access resources are activated or deactivated) included in the downlink control information (e.g., the second downlink control information).

[0225] In the embodiment of the present disclosure, when the UE receives the second downlink control information after the random access-related configuration information is received, if the first information (e.g., the indication information related to whether the first random access resources are activated or deactivated) included in the random access-related configuration information is different from the first information included in the downlink control information (e.g., the second uplink control information), the UE uses the first information included in the downlink control information, or the UE ignores the first information included in the random access-related configuration information but uses the first information included in the downlink control information. The advantage is that it avoids the problem of high random access latency caused by random access failure that occurs when the UE is unable to correctly select the activated first random access resource due to the inconsistency of the random access related configuration information and the indication of activation or deactivation of the first random access resources included in the downlink control information.

[0226] In the embodiment of the present disclosure, when the UE receives the random access-related configuration information after the downlink control information (e.g., the second downlink control information) is received, , if the first information (e.g., the indication information of activation or deactivation of the first random access resources) included in the random access-related configuration information is not the same as the first information included in the downlink control information, the UE uses the first information included in the random access-related configuration information, or the UE ignores the first information included in the downlink control information but uses the first information included in the random access-related configuration information. The advantage is that it avoids the problem of high random access latency caused by random access failure that occurs when the UE is unable to correctly select the activated first random access resource due to the inconsistency of the random access related configuration information and the indication of activation or deactivation of the first random access resources included in the downlink control information.

[0227] In an optional implementation, ROs, including the first ROs and the second ROs, can be obtained in accordance with the random access-related configuration information.

[0228] Optionally, the UE may determine the activated or deactivated first random access resources (the first ROs, also referred to as physical random access channel resources, PRACH occasions) based on the random access-related configuration information and the second downlink control information (or the first downlink control information), and in particular, the first ROs and the second ROs are valid ROs obtained in accordance with a predetermined validation rule. For example, the validation rule may include: an RO on a random access slot (PRACH slot) is valid if it is on an uplink symbol (or uplink part) in the TDD configuration pattern, and / or an RO on a random access slot is a valid RO if it is not earlier than an SSB on the slot and / or the RO is at least N symbols after the last downlink symbol and / or the last SSB symbol on the current slot. In the embodiment of the present disclosure, the first ROs and the second ROs involved are valid ROs unless otherwise stated. The UE may transmit a random access preamble on the determined valid ROs.

[0229] Optionally, in the indicated ROs, the valid ROs may be determined based on a determination method for determining a RO validity. It is satisfied that all SSBs within an association period (a certain time period or duration of time) may be mapped to the corresponding valid ROs. A SSB-to-RO mapping period may map exactly all SSBs in one SSB period onto the desired random access resources. There may be one or more mapping periods in one association period. An SSB-to-RO association pattern period comprises one or more association periods, and the SSB-to-RO association patterns are the same in each association pattern period.

[0230] In the embodiment of the present disclosure, when a UE transmits a preamble on the first ROs for random access, it does not affect a UE that performs the random access on the second ROs determined based only on the random access-related configuration information.

[0231] In the embodiment of the present disclosure, a mapping relationship between the SSBs and the first ROs may be a predetermined mapping rule or order. For example, the predetermined mapping rule or order may include: firstly, the SSB indexes are mapped in ascending order of indexes of preambles in the ROs of one random access slot; secondly, the SSB indexes are mapped in ascending order to frequency-division multiplexed ROs in the frequency domain; thirdly, the SSB indexes are mapped to the time-division multiplexed ROs on that random access slot in the time domain; and finally, the SSB indexes are mapped on a next random access slot.

[0232] In an optional implementation, the SSBs may be mapped to a third RO and the first ROs, where the third RO is one of the second ROs that is not used for PRACH transmission. Optionally, the second RO that is not used for PRACH transmission is: a second RO that is not mapped to an Index_ssb SSB index in an association period, where the Index_ssb is acquired by the UE from either a system information block 1 (SIB1, first system message block) or ssb-PositionsInBurst (SSB position information) value in ServingCellConfigCommon (serving cell common configuration); and / or, the second RO that is not used for the PRACH transmission is a second RO that is not associated with the SSB index after a second number of association periods, where the second number may be the smallest integer in a set determined based on the PRACH configuration period, where the set may be determined based on the PRACH configuration period. For example, the set is {1, 2, 4, 8, 16, 32, 64} for the PRACH configuration period of 10, or, alternatively, the set is {1, 2, 4, 8, 16, 32} for the period of 20.

[0233] In the embodiment of the present disclosure, the configuration information related to the first random access resources may be used for four-step random access configuration information, or for two-step random access configuration information. The four-step random access configuration is used as an example in example embodiments of the present disclosure to illustrate the methods. However, the embodiments of the present disclosure are not limited thereto and may be extended or replaced with random access configurations for other features.

[0234] In the embodiment of the present disclosure, the first random access frequency resource indexes may be determined based on the random access-related configuration information, or may be determined based on the random access-related configuration information and the downlink control information (e.g., the second downlink control information or the first downlink control information).

[0235] In the embodiment of the present disclosure, the first random access frequency resource indexes may be determined based on the configured first random access resources, and the first uplink frequency resource index and / or the second uplink frequency resource index is determined based on the manner in which the first random access frequency resource indexes are determined (e.g., the first random access frequency resource indexes determined in the manner that will not be changed as the first random access resources are activated or deactivated).

[0236] Optionally, the first random access frequency resource indexes (which may also be referred to as frequency-domain indexes or frequency resource indexes or frequency-domain numbers or frequency numbers of the first ROs) are determined based on at least one of:

[0237] (1) a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources;

[0238] (2) a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources;

[0239] (3) the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources;

[0240] (4) the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; and / or

[0241] (5) the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0242] For example, the first random access resources may be physical random access channel frequency domain resources (PRACH frequency domain resources) with frequency numbers of n_RA {0,1,...,M-1}, where M is a total number of the random access frequency domain resources on a random access time unit.

[0243] In the embodiment of the present disclosure, the frequency start location of the first random access resources may be determined according to one or more of:

[0244] (1) obtaining a frequency domain start (location) of the first random access resources based on the random access-related configuration information;

[0245] (2) using a frequency start (location) of the second random access resources obtained based on the random access-related configuration information as the frequency domain start (location) of the first random access resources; and / or

[0246] (3) determining the frequency domain start (location) of the first random access resources based on the frequency start (location) of the second ROs obtained based on the random access-related configuration information, and a frequency domain offset of the frequency start location of the first random access resources with respect to the second random access resources.

[0247] In the embodiment of the present disclosure, the number of frequency domain resources of the first random access resources may be determined according to one or more of:

[0248] (1) a total number of frequency domain resources of the random access resources (e.g., msg1-FDMTotal) obtained based on the random access-related configuration information, and a number of frequency domain resources of the second random access resources (e.g., msg1-FDM);

[0249] wherein the number of frequency domain resources of the first random access resources is a difference between the total number of frequency domain resources of the random access resources and the number of frequency domain resources of the second random access resources, e.g., if the total number of frequency domain resources of the random access resources is 6 and the number of frequency domain resources of the second random access resources is 3, then the number of frequency domain resources of the first random access resources is "msg1­FDMTotal" - "msg1­FDM" =6-3=3.

[0250] It should be noted that the total number of frequency domain resources of the random access resources is greater than or equal to (not less than) the number of frequency domain resources of the second random access resources (or the number of frequency domain resources of the second random access resources is less than or equal to (not greater than) the total number of frequency domain resources of the random access resources); and / or

[0251] (2) obtaining the number of frequency domain resources of the first random access resources (e.g., msg1-FDM2) based on the random access-related configuration information.

[0252] In the embodiment of the present disclosure, the total number of frequency domain resources of the first random access resources may be determined according to one or more of:

[0253] (1) the total number of frequency domain resources of the random access resources (e.g., msg1-FDMTotal) included in the random access-related configuration information;

[0254] wherein the total number of frequency domain resources of the random access resources is a number of frequency domain random access resources on a random access time unit, where the frequency domain random access resources include the first random access resources and the second random access resources; and / or

[0255] (2) the number of frequency domain resources of the first random access resources (e.g., msg1-FDM2) and the number of frequency domain resources of the second random access resources (e.g., msg1-FDM) obtained based on the random access-related configuration information, e.g., a total of the msg1-FDM2 and the msg1-FDM.

[0256] In the embodiment of the present disclosure, the first random access frequency resource indexes may be determined based on the configured first random access resources.

[0257] In an optional implementation, a minimum of the first random access frequency resource indexes is greater than a maximum of the second random access frequency resource indexes. The maximum of the second random access frequency resource indexes is determined based on the number of frequency domain resources of the second random access resources. The first random access frequency resource indexes are in ascending order of frequencies from low to high, based on the number of frequency domain resources of the first random access resources, starting from the frequency start location of the first random access resources.

[0258] Specifically, the first random access frequency resource indexes may be that an uplink bandwidth part of the second random access resources is not included in the uplink bandwidth part (e.g., the first random access resources, as illustrated in FIGS. 5a to 5c, may be located on one side of the uplink bandwidth part of the second random access resources (as shown in FIGS. 5a and FIG. 5c) or both sides thereof (as shown in FIG. 5b), and if located on both sides, the first random access frequency resource indexes may skip the uplink bandwidth part of the second random access resources), the first random access frequency resource indexes (also referred to as the first ROs frequency resource indexes) are numbered in ascending order starting from the lowest frequency (i.e., the frequency domain start of the first random access resources) of the first random access resources. The start index of the first random access frequency resource indexes is equal to or greater (not less) than the number of frequency domain resources of the second random access resources (or the start index of the first random access frequency resource indexes is equal to or greater (not less) than the maximum frequency resource index of the second random access resources, wherein the maximum frequency resource index of the second random access resources is determined based on the number of frequency domain resources of the second random access resources included in the frequency domain-related configuration information of the random access resources. For example, as shown in FIGS. 5a to 5c, the number of frequency domain resources of the second random access resources is 2, the maximum frequency resource index of the second random access resources is #1, the first random access resources are numbered in ascending order in a part other than the uplink bandwidth of the second random access resources starting from #2, and the number of frequency domain resources of the first random access resources is 4, so that the first random access frequency resource indexes are #2 to #5.

[0259] This indexing method may be understood as a combined indexing method. The advantage of this indexing method is that by adopting a frequency domain joint indexing method for the first ROs and the second ROs that overlap in the time domain and are frequency-division multiplexed, the problem of random access failure due to the same RA-RNTI calculation result associated with the Frequency division multiplexed first and second ROs (that overlap in the time domain) may be solved, which helps to increase the success rate of random access for the UE and to reduce the random access latency.

[0260] In another optional implementation, the first random access frequency resource indexes are determined based on the following formula:

[0261]

[0262] where denotes a frequency-domain resource index of the first random access resources (which may be referred to simply as the first frequency number for convenience of description), , , denote the number of frequency domain resources of the first random access resource (e.g., msg1-FDM2), denotes the total number of frequency domain resources (e.g., msg1-FDMTotal), and denotes a modulo operation, e.g., MOD(4, 5) = 4, MOD(5, 5) = 0.

[0263] Optionally, the first frequency numbers , are ordered from left to right in order of frequencies of the first random access resources from small to large, where , corresponds to the lowest frequency resource index, and corresponds to the highest frequency resource index.

[0264] This indexing method may also be understood as a combined indexing method. The advantage of the first random access frequency resource indexing method is that it can solve the problem of RA-RNTI inconsistency caused by the adaption of the first random access resources that makes the frequency domain logical indexes change, to increase the success rate of random access, and reduce the random access latency.

[0265] The first frequency numbers are frequency-domain resource indexes respective to the first random access resources in the frequency-domain resource indexes of the random access frequency domain resources, where the random access frequency domain resources includes the first random access resources and the second random access resources, and the frequency-domain resource indexes of the random access frequency domain resources are numbered in ascending order in the uplink bandwidth part starting from the lowest frequency of the random access frequency domain resources .

[0266] FIG. 6b is illustrated as an example below, and FIGS. 6a and 6c may be followed by analogy and will not be repeated. The number of random access frequency domain resources is M=6, including K=4 first ROs and 2 second ROs, and the frequency resource indexes of the second ROs are numbered in ascending order starting from the lowest frequency of the second ROs in the uplink bandwidth part, i.e., {0,1}, wherein the frequency of the second RO respective to an index 1 is greater than that respective to the second RO respective to an index 1; the first ROs frequency resource indexes may be numbered in ascending order starting from the lowest frequency of the random access resources in the uplink bandwidth part (the lowest frequency of the first ROs in the example) (the second ROs are included when indexing) to obtain the frequency resource indexes {0,1,4,5} respective to the first ROs, i.e., the first frequency numbers , where k=0,1,... , K-1=0,1,2,3, then an indexing method shown in FIG. 6b may be obtained according to a formula , where the first ROs are sorted from left to right in order of frequencies from small to large.

[0267] In yet another optional implementation, the first random access frequency resource indexes h may also be determined based on the frequency start location of the first random access resources, and the number of frequency domain resources of the first random access resources. This indexing method may be understood as a separate indexing method.

[0268] Specifically, as shown in FIG. 7, the first random access frequency resource indexing method may be that, within an uplink bandwidth part which does not contain the second random access resources among the uplink bandwidth part (e.g., the first random access resources shown in FIG. 7), the first random access frequency resource indexes are numbered in ascending order starting from the lowest frequency (i.e., the frequency start location of the first random access resources) of the first random access resources, wherein the start index of the first random access frequency resource indexes is #0.

[0269] In the embodiment of the present disclosure, the first random access frequency resource indexes may be determined based on the activated first random access resources.

[0270] Optionally, the first information indicates that the first random access resources are activated and / or deactivated, the activated first random access frequency resource indexes are determined based on at least one of:

[0271] (1) a frequency start location of the activated first random access resources and a number of frequency domain resources of the activated first random access resources;

[0272] (2) a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the activated first random access resources;

[0273] (3) the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and the number of frequency domain resources of the second random access resources;

[0274] (4) the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and a total number of frequency domain resources of the random access resources; or

[0275] (5) the frequency start location of the activated first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0276] In an optional implementation, as shown in FIG. 8, the method of determining the first random access frequency resource indexes is that, within an uplink bandwidth part that does not contain the second random access resources among the uplink bandwidth part, the first random access frequency resource indexes are determined by indexing the frequency domain resources of the activated first random access resources in ascending order starting from the lowest frequency of the activated first random access resources (i.e., the frequency start location of the first random access resources), wherein the start index of the first random access frequency resource indexes is equal to or greater (not less) than the number of frequency domain resources of the second random access resources (or the start index of the first random access frequency resource indexes is equal to or greater (not less) than the maximum index of frequency domain resources of the second random access resources), wherein the maximum index of frequency domain resources of the second random access resources is determined according to the number of frequency domain resources of the second random access resources included in the frequency domain related configuration information of the random access resources. The advantage of this indexing method is that by adopting a joint indexing method for the first ROs and the second ROs that overlap in the time domain and are frequency-division multiplexed, it can solve the problem of random access failures caused by the same RA-RNTI calculation results associated with the frequency division multiplexed first and second ROs (that overlap in the time domain), which helps to improve the success rate of random access for the UE and reduce the random access latency.

[0277] In another optional implementation, as shown in FIG. 9, the method of determining the first random access frequency resource indexes may also be as follows: , where is a modulo operation, e.g., MOD(4, 5) = 4, MOD(5, 5) = 0, and , , are the frequency-domain resource indexes of the first random access resources (which may be abbreviated as the first frequency numbers for convenience of description), P is the number of frequency domain resources of the activated first random access resources, M is the number of frequency domain resources of the random access resources (including the activated first and second ROs). Specifically, the first frequency numbers are sorted from left to right in order of frequencies of the activated first random access resources from small to large, where , correspond to the lowest frequency resource index, and corresponds to the highest frequency resource index. The advantage of this frequency resource indexing method of the first random access resources is that it can solve the problem of RA-RNTI inconsistency caused by a change in frequency domain logical indexes due to the adaptation of the first random access resources, increasing the success rate of random access, and reducing the random access latency.

[0278] The first frequency numbers are frequency numbers respective to the activated first ROs in the frequency numbers of the random access frequency domain resources. The random access frequency domain resources include the activated first and second ROs. The frequency numbers of the random access frequency domain resources are obtained by indexing the random access frequency domain resources in ascending order starting from the lowest frequency in the uplink bandwidth part.

[0279] In yet another optional implementation, as shown in FIG. 10, the method of determining the first random access frequency resource indexes may be that, within an uplink bandwidth part that does not contain the second random access resources among the uplink bandwidth part (e.g., the first random access resources shown in FIG. 10), the first random access frequency resource indexes are determined by indexing the frequency domain resources of the activated first random access resources in ascending order starting from the lowest frequency (i.e., the frequency start location of the first random access resource) of the activated first random access resources, wherein the start index of the first random access frequency resource indexes is #0.

[0280] Optionally, the link bandwidth part in at least one of the above embodiments may be an initial uplink bandwidth part or an active uplink bandwidth part. Optionally, upon initial access, the uplink bandwidth part is the initial uplink bandwidth part; otherwise, the uplink bandwidth part is the active uplink bandwidth part.

[0281] Optionally, the lowest frequency in at least one of the above embodiments may be a combination of one or more of:

[0282] (1) a frequency start of the first random access resources obtained according to the random access-related configuration information;

[0283] (2) a frequency start of the second random access resources obtained according to the random access-related configuration information; and / or

[0284] (3) one with a lower frequency of the frequency start of the first random access resources and the frequency start of the second random access resources obtained according to the random access-related configuration information.

[0285] Optionally, if the frequency start of the first random access resources and the frequency start of the second random access resources are the same, the lowest frequency is any one of the two.

[0286] In the embodiment of the present disclosure, the total of the number of frequency domain resources of the first random access resources (e.g., msg1-FDM2) and the number of frequency domain resources of the second random access resources (e.g., msg1-FDM) is not greater than a maximum value (e.g., 8) of the number of frequency domain resources of the second random access resources (msg1-FDM), which is advantageous in that it does not affect calculation of RA-RNTIs in the standard, and involves a little change in the standard.

[0287] As an example, the number of frequency domain resources of the first random access resources may be implicitly indicated. For example, based on the number of frequency domain resources of the second random access resources (e.g., msg1-FDM) and based on the maximum value (e.g., 8) of the number of frequency domain resources of the second random access resources, the maximum value of the number of frequency domain resources of the first random access resources may be determined.

[0288] In the embodiment of the present disclosure, the first uplink resource is a first available first random access resource among the activated first random access resources; and / or, the first uplink resource is selected from the configured second random access resources and the activated first random access resources in accordance with a first criterion; and / or, the first uplink resource is a first available random access resource among the second random access resources and the activated first random access resources.

[0289] Optionally, if indication information about whether only the activated first random access resources may be used which is included in the random access related configuration information is configured, the UE selects a first available first random access resource among the first random access resources or selects a random access resource in accordance with a first criterion; otherwise, the UE selects a first available random access resource among the second random access resources and the activated first random access resources.

[0290] In the embodiment of the present disclosure, the first criterion comprises at least one of:

[0291] (1) if the second random access resources and the activated first random access resources are time-division multiplexed (if the first ROs and the second ROs do not overlap in the time domain), and the first uplink resource is the first available random access resource among the second random access resources and the activated first random access resources, the UE selects a first available RO among the second ROs and the activate first ROs as the first uplink resource; or

[0292] (2) if the second random access resources and the activated first random access resources are frequency-division multiplexed (if the first ROs and the second ROs are on the same time unit, but do not overlap in the frequency domain), and the first uplink resource is the first available first random access resource among the activated first random access resources, the UE may selects a first available RO among the first ROs as the first uplink resource first.

[0293] Optionally, for a case where the first uplink resource is included in the second random access resources and the activated first random access resources, the second random access resources are the second random access resources in the configured second random access resources that are not associated with the SSB indexes during an association period and / or the second random access resources that are not associated with the SSB indexes after an integer number of association periods.

[0294] An embodiment of the present disclosure may reduce a random access conflict probability between a UE which is configured with the first ROs and a UE which is not configured with the first ROs, increase the success rate of random access for the UE, and reduce the random access latency.

[0295] In the embodiment of the present disclosure, step S430 may specifically comprise at least one of:

[0296] after a first time interval in which the first downlink control information is received, monitoring the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window; or

[0297] within the first time interval in which the first downlink control information is received, monitoring the PDCCH for receiving the random access response based on a second RA-RNTI, where the second RA-RNTI being determined based on the first uplink resource,

[0298] wherein the first time interval is an valid time interval for the first downlink control information.

[0299] Optionally, the UE monitors the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window, in a case that the first random access resources indicated by the first information are different from the first random access resources indicated by the first downlink control information.

[0300] Optionally, the PDCCH is monitored based on the first RA-RNTI in the second time window for receiving a random access response, when at least one of the following is satisfied:

[0301] (1) the frequency resource index of the first uplink resource is not equal to the frequency resource index of the second uplink resource; or

[0302] (2) the first downlink control information indicates that the first uplink resource is deactivated,

[0303] wherein the second uplink resource and the first uplink resource have the same frequency location, and / or an index s_id of the first OFDM symbol of the second uplink resource and an index t_id of the first slot of the second uplink control resource in a system frame, etc., are the same as that of the first uplink resource.

[0304] Optionally, the UE monitors the PDCCH for receiving the random access response based on the first RA-RNTI in the second time window, in a case that at least one of the following conditions is satisfied: the PDCCH is not monitored; and / or the PDCCH is monitored, but the least significant bit (LSB) of a SFN field of the monitored PDCCH is different from a corresponding LSB of the SFN of the first uplink resource.

[0305] As an example, an example flow of a UE receiving a random access response is illustrated in FIG. 11, wherein UE1 transmits a PRACH, for example, UE1 transmits a preamble (msg1) on the first RO1 (first uplink resource), and UE1 attempts to detect a DCI format 1_0 scrambled with a corresponding RA-RNTI (the second RA-RNTI determined based on the first RO1) during a window (i.e., second time window) configured by higher layer signaling, in the first time window (the start time point of which is the same as that of the second time window), UE1 does not receive the msg2 transmitted to the UE1 based on the second RA-RNTI, and UE1 receives first downlink control information, and after the first downlink control information takes effect after the first time interval, UE1 will receive the msg2 (random access response) based on the first RA-RNTI in the third time window. The start time point of the first time interval is at the beginning of receiving the first downlink control information, and after a time interval for the first downlink control information to take effect, the third time window is started after the first time interval, and the end time point of the third time window is the end time point of the second time window.

[0306] After receiving the first downlink control information, UE2 transmits the msg1 on the first RO2 and will receive the Msg2 in a RAR reception window based on a third RA-RNTI, wherein the third RA-RNTI is determined based on the first RO2. Because the RA-RNTI based on the first RO1 (the second RA-RNTI) and the RA-RNTI based on the first RO2 (the third RA-RNTI) may have a same value due to a change in frequency resource indexes etc., UE1 receives the msg2 based on the first RA-RNTI to avoid conflicts. Specifically, when UE2 receives the msg2 transmitted to UE1, since the msg2 is transmitted based on the first RA-RNTI, UE2 will not decode the msg2 transmitted to UE1 based on the third RA-RNTI, which solves the problem of UE decoding the msg2 of other UEs due to the RA-RNTI conflict, reduces the conflict probability of random access and improves the reliability of random access.

[0307] Optionally, UE starts the second time window that begins with the reception of the first symbol of the earliest control resource set (CORESET) of a PDCCH of a Type1-PDCCH common search space (CSS) set, where the symbol has at least one symbol, and the symbol duration thereof corresponds to a subcarrier spacing (SCS) of the Type1-PDCCH CSS set, after the last symbol of the last PRACH occasion respective to the PRACH transmission. Based on the SCS of the Type1-PDCCH CSS set, a duration of the second time window expressed in number of slots is provided by higher layer signaling ra-ResponseWindow (random access response window).

[0308] In the second time window or during running of the second time window, UE may receive the msg2 based on the first RA-RNTI if UE satisfies at least one of the following conditions (referred to as the first conditions):

[0309] (1) the first downlink control information is received, and prior to that, the UE does not detect a DCI format 1_0 scrambled based on the second RA-RNTI;

[0310] (2) the UE detects the first downlink control information or format thereof scrambled based on a fifth RNTI, and the UE does not detect the DCI format 1_0 scrambled based on the second RA-RNTI;

[0311] (3) the UE receives the first downlink control information, and prior to that, detects the DCI format 1_0 scrambled based on the second RA-RNTI, but the LSB of the SFN field in the DCI format 1_0, if included and applicable, is different from the corresponding LSB of the SFN for which the UE transmits the PRACH (the first RO1);

[0312] (4) the UE detects the first downlink control information or format thereof scrambled based on the fifth RNTI, and prior to that, detects the DCI format 1_0 scrambled based on the second RA-RNTI, but the LSB of the SFN field in the DCI format 1_0, if included and applicable, is different from the corresponding LSB of the SFN for which the UE transmits the PRACH (the first RO1);

[0313] (5) the UE receives the first downlink control information, and prior to that, is unable to correctly receive transport blocks in the corresponding PDSCH;

[0314] (6) the UE detects the first downlink control information or format thereof scrambled based on the fifth RNTI, and prior to that, is unable to correctly receive transport blocks in the corresponding PDSCH;

[0315] (7) the UE receives the first downlink control information, and prior to that, the higher layer fails to recognize a random access preamble identifier (RAPID) related to the PRACH transmission from the PRACH transmission of the UE; or

[0316] (8) the UE detects the first downlink control information or format thereof scrambled based on the fifth RNTI, and prior to that, the higher layer fails to identify the RAPID related to the PRACH transmission from the PRACH transmission of the UE.

[0317] Specifically, if the above conditions are satisfied, the UE may perform the following operations:

[0318] (1) detecting the DCI format 1_0 respective to the random access response based on the first RA-RNTI;

[0319] (2) detecting, after the first time interval, the DCI format 1_0 respective to the random access response based on the first RA-RNTI;

[0320] (3) detecting, in the second time window or during the running of the second time window, the DCI format 1_0 respective to the random access response based on the first RA-RNTI;

[0321] (4) after the first time interval, detecting, in the second time window or during running of the second time window, the DCI format 1_0 respective to the random access response based on the first RA-RNTI;

[0322] (5) after the first downlink control information is received, or after the first time interval in which the first downlink control information or format thereof scrambled based on the fifth RNTI is detected, detecting, in the second time window or during running of the second time window, the DCI format 1_0 respective to the random access response based on the first RA-RNTI;

[0323] (6) the higher layer may instruct the physical layer to perform the PRACH transmission;

[0324] (7) after the first downlink control information is received, or after the first time interval in which the first downlink control information or format thereof scrambled based on the fifth RNTI is detected, the higher level may instruct the physical layer to perform the PRACH transmission;

[0325] (8) stopping the second time window and starting the third time window in which the DCI format 1_0 scrambled based on the first RA-RNTI is detected, with a start time of the third time window being after the UE receives the first downlink control information, or after the first downlink control information or format thereof scrambled based on the fifth RNTI is detected, or after the first time interval in which the first downlink control information is received, or after the first time interval in which the first downlink control information or format thereof scrambled based on the fifth RNTI is detected; or

[0326] (9) the higher layer may instruct the physical layer to perform the PRACH transmission. If the higher layer requires the UE to transmit a PRACH after the UE receives the first downlink control information, or after the first downlink control information or format thereof scrambled based on the fifth RNTI is detected, or after the first time interval in which the first downlink control information is received, or after the first time interval in which the first downlink control information or format thereof scrambled based on the fifth RNTI is detected.

[0327] Optionally, for the first time interval of at least one of the above embodiments, it may specifically refer to the following time intervals after the UE receives the first downlink control information or detects the last symbol of the first downlink control information or format thereof scrambled based on the fifth RNTI:

[0328] (1) NT1 (in milliseconds), where NT1 is a time duration of N1 symbols, which corresponds to the PDSCH processing time of a PDCCH payload for the smallest SCS configuration respective to μ in SCS configurations of the DCI format 1_0, the corresponding PDSCH, and the corresponding PRACH;

[0329] (2) NT2 (in milliseconds), where NT2 corresponds to a duration of N2 symbols of the PDCCH processing time of the UE processing capability 1; optionally, this duration is related to the SCS;

[0330] (3) NT3 (in milliseconds), where NT3 is a duration of N3 symbols, after NT3 information related to the activation of the first ROs in the first downlink control information takes effect; optionally, this duration is related to the SCS;

[0331] (4) NT2+ NT3 (in milliseconds); or

[0332] (5) NT2+ Delay or NT3+ Delayy or NT2+NT3+ Delay (in milliseconds), where Delay is related to a frequency range, e.g., Delay=0.5 milliseconds for FR1 and Delay=0.25 milliseconds for FR2.

[0333] In the embodiment of the present disclosure, the UE receives the random access response based on the second RA-RNTI within the first time interval in which the UE receives the first downlink control information, or within the first time interval in which the UE detects the first downlink control information or format thereof scrambled based on the fifth RNTI. The benefit is that the UE may still receive the random access response based on the second RA-RNTI before the first downlink control information, which avoids the problem of RA-RNTI conflict that occurs when different RA-RNTIs determined based on the newly indicated ROs are used within an valid time of the first downlink control information, and improves the performance of random access.

[0334] In the embodiment of the present disclosure, the first RA-RNTI is determined based on at least one of:

[0335] (1) the first uplink resource and the first random access resources indicated by the first downlink control information;

[0336] optionally, and specifically, may be activated first random access resources determined based on the first uplink resource and based on the first downlink control information.

[0337] (2) the first uplink resource and the second uplink resource;

[0338] wherein the second uplink resource is determined based on the first downlink control information, and specifically, the second uplink resource is determined based on the indication information about the first random access resources in the first downlink control information.

[0339] (3) the second RA-RNTI and the third RA-RNTI;

[0340] wherein the second RA-RNTI is determined based on the first uplink resource and the third RA-RNTI is determined based on the second uplink resource.

[0341] optionally, the first RA-RNTI is determined based on an absolute value of a difference between the second RA-RNTI and the third RA-RNTI;

[0342] optionally, the first RA-RNTI is determined based on a total of the second RA-RNTI and the third RA-RNTI.

[0343] (4) a frequency resource index of the first uplink resource and a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information;

[0344] optionally, the first RA-RNTI is determined based on a frequency resource index of the first uplink resource and a third number, the third number is a number of the first random access resources indicated by the first downlink control information, and specifically, the first RA-RNTI is determined based on a first index, the first index is a total of the frequency resource index of the first uplink resource and the third number; for example, if the first uplink resource has a frequency resource index of 3 and the third number is 4, then the first index is 3+4=7.

[0345] (5) the frequency resource index of the first uplink resource and a number of frequency domain resources respective to the first random access resources indicated by the first information;

[0346] optionally, the first RA-RNTI is determined based on the frequency resource index of the first uplink resource and a fourth number, the fourth number is a number of frequency domain resources respective to the first random access resources indicated by the first information, and the first RA-RNTI is determined based on a second index, the second index is a total of the frequency resource index of the first uplink resource and the fourth number, e.g., if the frequency resource index of the first uplink resource is 3 and the fourth number is 2, then the second index is 3+2=5.

[0347] (6) the frequency resource index of the first uplink resource, the number of frequency domain resources respective to the first random access resources indicated by the first downlink control information, and the number of frequency domain resources respective to the first random access resources indicated by the first information;

[0348] optionally, the first RA-RNTI may be computed as:

[0349] RA-RNTI = 1 + s_id + 14 x t_id + 14 x 80 x f_id + 14 x 80 x 8 x ul_carrier_id + 14 x 80 x k x 2 x diff

[0350] where s_id is the index of the first OFDM symbol of the first uplink resource (0 ≤ s_id < 14), t_id is the index of the first slot of the first uplink resource in a system frame (0 ≤ t_id < 80), f_id is the index of the first uplink resource in the frequency domain (0 ≤ f_id <8), ul_carrier_id is the UL carrier used for random access preamble transmission (0 for NUL carrier, and 1 for SUL carrier), k is the maximum value of f_id (e.g., the number of frequency domain resources of the random access resources, e.g., k = 8), and diff is a difference between the third number and the fourth number, or an absolute value of the difference between the third number and the fourth number.

[0351] Optionally, the first RA-RNTI is determined based on the difference between the third number and the fourth number, the difference is an absolute value of the difference between the third number and the fourth number. As an example, the third number is 4, and the frequency resource indexes of the first ROs or the activated first ROs are in the range of 0,1,2,3. Based on the first downlink control information, it is determined that the first RO respective to a frequency resource index of 3 is deactivated, and the number of the first ROs in the frequency domain becomes 3 (the fourth number), i.e., 0,1,2, and the difference between the third number and the fourth number is 3-4=-1. If the UE selects the frequency resource index of 3 before receiving the first downlink control information, a new frequency resource index may be determined to be 3+(-1)=2 based on the formula by adding the frequency resource index to the difference, and the UE will calculate the first RA-RNTI based on the frequency resource index of 2. As another example, if, based on the first downlink control information, it is determined that the first RO with a frequency resource index of 4 is activated and the fourth number is 5, the difference between the third number and the fourth number is 5-4=1, and if the frequency resource index respective to the first uplink resource is 3, then a new frequency resource index may be determined to be 3+1=4 based on the formula by adding the frequency resource index to the difference, and the UE will calculate the first RA-RNTI based on the frequency resource index of 4.

[0352] Optionally, the first RA-RNTI may also be determined based on a modulo operation of the third number and / or the fourth number. As an example, the number (the third number) of frequency domain resources of the first ROs or the activated first ROs is 4, and the corresponding frequency resource indexes are 0,1,2,3. Based on the second downlink control information, it is determined that the first RO respective to a frequency resource index of 0 is deactivated, and at this time the number of frequency domain resources of the activated first ROs is 3. If the UE selects the frequency resource index of 3, then according to a formula of 3mod3=0, the UE will calculate the first RA-RNTI according to the frequency resource index of 0. As another example, if it is determined, based on the second downlink control information, that the frequency resource index of 1 is deactivated, the maximal frequency resource index range becomes 3, and if the UE selects the frequency resource index of 1, then according to a formula of 1mod3= 1, the UE will deactivate the first RA-RNTI according to the frequency resource index of 1; or

[0353] (7) a number of frequency domain resources respective to configured second random access.

[0354] Optionally, the third number and the fourth number described above may also include the number of frequency domain resources respective to the second random access resources. For example, the third number is a total of the number of frequency domain resources of the activated first random access resources determined based on the first downlink control information and the number of frequency domain resources respective to the second random access resources, and the fourth number is a total of the number of frequency domain resources of the activated first random access resources determined based on the first information and the number of frequency domain resources respective to the second random access resources, or the first RA-RNTI may be computed by directly substituting into the calculation of the third number and the fourth number as described above, and a similar calculation process will not be described in detail.

[0355] Optionally, the first RA-RNTI, the second RA-RNTI and / or the third RA-RNTI may be determined based on random access resource related information of the first uplink resource, the random access resource related information being used to indicate whether the first uplink resource is related to a second feature. Optionally, the random access resource related information may be represented with 1 bit. For example, 0 indicates that the first uplink resource is not related to the second feature, i.e., the type of the first uplink resource is a second random access resource, and 1 indicates that the first uplink resource is related to the second feature, i.e., the type of the first uplink resource is a first random access resource, but is not limited to thereto.

[0356] Optionally, the first RA-RNTI, the second RA-RNTI, and / or the third RA-RNTI may be computed as:

[0357] RA-RNTI = 1 + s_id + 14 x t_id + 14 x 80 x f_id + 14 x 80 x 8 x ul_carrier_id + 14 x 80 x k x 2 x RO_fdm_id

[0358] where s_id is the index of the first OFDM symbol of the first uplink resource (0 ≤ s_id < 14), t_id is the index of the first slot of the first uplink resource in a system frame (0 ≤ t_id < 80), f_id is the index of the first uplink resource in the frequency domain (0 ≤ f_id <8), ul_carrier_id is the UL carrier used for random access preamble transmission (0 for NUL carrier, and 1 for SUL carrier), k is the maximum value of f_id (e.g., the number of frequency domain resources of the random access resources, e.g., k = 8), and RO_fdm_id is the random access resource type of the first uplink resource. Optionally, RO_fdm_id = 0, 1 (indicating the first RO or the second RO), e.g., 0 for the first RO and 1 for the second RO, or 0 for the second RO and 1 for the first RO.

[0359] In the embodiment of the present disclosure, the advantage of receiving a random access response by the UE based on the first RA-RNTI is to solve the problem of inconsistent RA-RNTI calculation results associated with the same RO due to a change in the frequency resource indexes of the first ROs due to the activation or deactivation of the first random access resources, and to help increase the success rate of random access and reduce the random access latency.

[0360] When the UE random access load in the network is small, the scheme of the embodiment of the present disclosure can avoid that the base station still needs to frequently detect the PRACH to monitor the random access initiated by the UE, which leads to the waste of energy in the network, and can adaptively adjust the random access resources configured in the network without affecting the random access performance of the UE, to realize energy saving in the network.

[0361] In the embodiment of the present disclosure, there is provided a method for determining an RA-RNTI associated with first random access resources (e.g., first ROs), which may be applied to a four-step random access scenario, and optionally, the RA-RNTI may be used to determine a first RA-RNTI in the embodiment of the present disclosure.

[0362] In an optional implementation, if additional PRACH resources (e.g., the first random access resources, or the first ROs) are configured, the RA-RNTI associated with the additional PRACH occasion (e.g., the first RO or an additional RO) in which the random access preamble is transmitted or the RA-RNTI associated with the last valid additional PRACH occasion in the set of PRACH occasions for msg1 repetition is computed as:

[0363] RA-RNTI = 1 + s_id + 14 x t_id + 14 x 80 x f_id + 14 x 80 x 8 x ul_carrier_id

[0364] where s_id is the index of the first OFDM symbol of the additional PRACH occasion (0 ≤ s_id < 14), t_id is the index of the first slot of the additional PRACH occasion in a system frame (0 ≤ t_id < 80), where the subcarrier spacing to determine t_id is based on the value of μ for μ = {0, 1, 2, 3}, and for μ = {5, 6}, t_ id is the index of the 120 kHz slot in a system frame that contains the additional PRACH occasion (0 ≤ t_id < 80), ul_carrier_id is the UL carrier used for random access preamble transmission (0 for NUL carrier, and 1 for SUL carrier), and f_id is the index of the additional PRACH occasion in the frequency domain (M_RA ≤ f_id < 8), where the value of M_RA is determined according to at least one of the followings.

[0365] Optionally, if one time instance includes PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed (Frequency division multiplexed) with the additional PRACH occasion, M_RA is equal to a higher layer parameter msg1-FDM (if configured); otherwise, M_RA is equal to zero.

[0366] Optionally, if one time instance does not include PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, M_RA is equal to zero; otherwise, M_RA is equal to the higher layer parameter msg1-FDM (if configured).

[0367] Optionally, if one time instance includes PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, and PRACH occasion(s) and the additional PRACH occasion are on a same uplink (UL) carrier used for transmitting a random access preamble (e.g., a normal uplink (NUL) carrier or a supplementary uplink (SUL) carrier), M_RA is equal to the higher layer parameter msg1-FDM (if configured); otherwise, M_RA is equal to zero.

[0368] Optionally, if one time instance does not include PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed on the same uplink carrier (e.g., the NUL carrier or the SUL carrier) as the additional PRACH occasion, M_RA is equal to zero; otherwise, M_RA is equal to the higher layer parameter msg1-FDM (if configured).

[0369] Optionally, if one time instance includes both an additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble, M_RA is equal to the higher layer parameter msg1-FDM (if configured); otherwise, M_RA is equal to zero.

[0370] Optionally, if one time instance does not include both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble, M_RA is equal to zero; otherwise, M_RA is equal to the higher layer parameter msg1-FDM (if configured).

[0371] Optionally, if both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble are included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance, M_RA is equal to the higher layer parameter msg1-FDM (if configured); otherwise, M _RA is equal to zero.

[0372] Optionally, if both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or non-additional RO or a default RO) for transmitting the random access preamble are not included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance, M_RA is equal to zero; otherwise, M_RA is equal to the higher layer parameter msg1-FDM (if configured).

[0373] In another optional implementation, the RA-RNTI associated with the PRACH occasion in which the random access preamble is transmitted, or the RA-RNTI associated with the last valid PRACH occasion in the set of PRACH occasions for Msg1 repetition is computed as:

[0374] RA-RNTI = 1 + s_id + 14 x t_id + 14 x 80 x f_id + 14 x 80 x 8 x ul_carrier_id

[0375] where s_id is the index of the first OFDM symbol of the PRACH occasion (0 ≤ s_id < 14), and t_id is the index of the first slot of the PRACH occasion in a system frame (0 ≤ t_id < 80), where the subcarrier spacing to determine t_id is based on the value of μ for μ = {0, 1, 2, 3}, and for μ = {5, 6}, t_id is the index of the 120 kHz slot in a system frame that contains the PRACH occasion (0 ≤ t_id < 80), ul_carrier_id is the UL carrier used for random access preamble transmission (0 for NUL carrier, and 1 for SUL carrier), and f_id is the index of the PRACH occasion in the frequency domain (M_RA ≤ f_id < 8), where the value of M_RA is determined according to at least one of the followings.

[0376] Optionally, if the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) and one time instance includes PRACH occasion(s) (e.g., the second RO or a non-additional or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, M_RA is equal to the higher layer parameter msg1-FDM (if configured); otherwise, M_RA is equal to zero.

[0377] Optionally, if the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) and one time instance includes PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, and the PRACH occasion(s) and the additional PRACH occasion are on the same UL carrier (e.g., the NUL carrier or the SUL carrier) used for transmitting the random-access preamble, M_RA is equal to the higher layer parameter msg1-FDM (if configured); otherwise, M_RA is equal to zero.

[0378] Optionally, if the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) and one time instance includes both the additional PRACH occasion (e.g., the first RO) for transmitting the random access preamble and PRACH occasion (s) (e.g., the second RO or a non-additional RO or a default RO), M_RA is equal to the higher layer parameter msg1-FDM ( if configured); otherwise, M_RA is equal to zero.

[0379] Optionally, if the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) and both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble are included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance, M_RA is equal to the higher layer parameter msg1-FDM (if configured); otherwise, M_RA is equal to zero.

[0380] Optionally, if the PRACH occasion is a non-additional PRACH occasion (e.g., the second RO or a non-additional RO or a default RO), or if the PRACH occasion is an additional PRACH occasion (if configured) and one time instance does not include PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, M _RA is equal to zero; otherwise, M_RA is equal to the higher layer parameter msg1-FDM (if configured).

[0381] Optionally, if the PRACH occasion is a non-additional PRACH occasion (e.g., the second RO or a non-additional RO or a default RO), or if the PRACH occasion is an additional PRACH occasion (if configured) and one time instance does not include PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency division multiplexed on the same uplink carrier (e.g., NUL carrier or SUL carrier) as the additional PRACH occasion , M_RA is equal to zero; otherwise, M_RA is equal to the higher layer parameter msg1-FDM (if configured).

[0382] Optionally, if the PRACH occasion is a non-additional PRACH occasion (e.g., the second RO or a non-additional RO or a default RO), or if the PRACH occasion is an additional PRACH occasion (if configured), one time instance does not include both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., a second RO or non-additional RO or a default RO) for transmitting a random access preamble, M_RA is equal to zero; otherwise, M_RA is equal to the higher layer parameter msg1-FDM (if configured).

[0383] Optionally, if the PRACH occasion is a non-additional PRACH occasion (e.g., the second RO or a non-additional RO or a default RO), or the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured), and both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble are not included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance, M_RA is equal to zero; otherwise, M_RA is equal to the higher layer parameter msg1-FDM (if configured).

[0384] The method for determining the RA-RNTI associated with the first RO used for transmitting the random access preamble which is presented in the embodiment of the present disclosure can effectively avoid the problem of RA-RNTI conflicts caused by the first RO and the second RO having the same frequency resource (or frequency domain) index when the first RO and the second RO are frequency-division multiplexed, reduce the probability of random access conflicts, and improve the performance of random access.

[0385] In the embodiment of the present disclosure, there is provided a method for determining an MSGB-RNTI associated with first random access resources (e.g., first ROs), which may be applied to a two-step random access scenario, and optionally, the MSGB-RNTI may be used to determine a first RA-RNTI in the embodiment of the present disclosure.

[0386] In an optional implementation, if additional PRACH resources (e.g., the first random access resources, or the first ROs) are configured, the MSGB-RNTI associated with the additional PRACH occasion (e.g., the first RO) in which the random access preamble (RAP) is transmitted or the MSGB-RNTI associated with the last valid additional PRACH occasion in the set of additional PRACH occasions for Msg1 repetition is computed as:

[0387] MSGB-RNTI = 1 + s_id + 14 x t_id + 14 x 80 x f_id + 14 x 80 x 8 x ul_carrier_id + 14 x 80 x 8 x 2

[0388] where s_id is the index of the first OFDM symbol of the additional PRACH occasion (0 ≤ s_id < 14), and t_id is the index of the first slot of the additional PRACH occasion in a system frame (0 ≤ t_id < 80), where the subcarrier spacing to determine t_id is based on the value of μ for μ = {0, 1, 2, 3}, and for μ = {5, 6}, t_id is the index of the 120 kHz slot in a system frame that contains the additional PRACH occasion (0 ≤ t_id < 80), ul_carrier_id is the UL carrier used for random access preamble transmission (0 for NUL carrier, and 1 for SUL carrier), and f_id is the index of the additional PRACH occasion in the frequency domain (M_RA2 ≤ f_id < 8), where the value of M_RA2 is determined according to at least one of the followings.

[0389] Optionally, if one time instance includes PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured); otherwise, M_RA2 is equal to zero.

[0390] Optionally, if one time instance does not include PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, M_RA2 is equal to zero; otherwise, M_RA2 is equal to a higher layer parameter msgA-RO-FDM (if configured).

[0391] Optionally, if one time instance includes PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, and PRACH occasion(s) and the additional PRACH occasion are on the same UL carrier (e.g., the NUL carrier or the SUL carrier) used for transmitting the random-access preamble, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured); otherwise, M_RA2 is equal to zero.

[0392] Optionally, if one time instance does not include PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed on the same uplink carrier (e.g., the NUL carrier or the SUL carrier) as the additional PRACH occasion, M_RA2 is equal to zero; otherwise, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured).

[0393] Optionally, if one time instance includes both an additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured); otherwise, M_RA2 is equal to zero.

[0394] Optionally, if one time instance does not include both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble, M_RA2 is equal to zero; otherwise, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured).

[0395] Optionally, if both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble are included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured); otherwise, M_RA2 is equal to zero.

[0396] Optionally, if both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or non-additional RO or a default RO) for transmitting the random access preamble are not included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance, M_RA2 is equal to zero; otherwise, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured).

[0397] In another optional implementation, the MSGB-RNTI associated with the PRACH occasion in which the random access preamble is transmitted, or the MSGB-RNTI associated with the last valid PRACH occasion in the set of PRACH occasions for the Msg1 repetition is computed as:

[0398] MSGB-RNTI = 1 + s_id + 14 x t_id + 14 x 80 x f_id + 14 x 80 x 8 x ul_carrier_id + 14 x 80 x 8 x 2

[0399] where s_id is the index of the first OFDM symbol of the PRACH occasion (0 ≤ s_id < 14), and t_id is the index of the first slot of the PRACH occasion in a system frame (0 ≤ t_id < 80), where the subcarrier spacing to determine t_id is based on the value of μ for μ = {0, 1, 2, 3}, and for μ = {5, 6}, t_id is the index of the 120 kHz slot in a system frame that contains the PRACH occasion (0 ≤ t_id < 80), ul_carrier_id is the UL carrier used for random access preamble transmission (0 for NUL carrier, and 1 for SUL carrier), and f_id is the index of the PRACH occasion(s) in the frequency domain (M_RA2 ≤ f_id < 8), where the value of M_RA2 is determined according to at least one of the followings.

[0400] Optionally, if the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) and one time instance includes PRACH occasion(s) (e.g., the second RO or a non-additional or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured); otherwise, M_RA2 is equal to zero.

[0401] Optionally, if the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) and one time instance includes PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, and the PRACH occasion(s) and the additional PRACH occasion are on the same UL carrier (e.g., the NUL carrier or the SUL carrier) used for transmitting the random-access preamble, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured); otherwise, M_RA2 is equal to zero.

[0402] Optionally, if the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) and one time instance includes both the additional PRACH occasion (e.g., the first RO) for transmitting the random access preamble and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO), M_RA2 is equal to the higher layer parameter msgA-RO-FDM ( if configured); otherwise, M_RA2 is equal to zero.

[0403] Optionally, if the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) and both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble are included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured); otherwise, M_RA2 is equal to zero.

[0404] Optionally, if the PRACH occasion is a non-additional PRACH occasion (e.g., the second RO or a non-additional RO or a default RO), or the PRACH occasion is an additional PRACH occasion (if configured) and one time instance does not include PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency-division multiplexed with the additional PRACH occasion, M _RA2 is equal to zero; otherwise, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured).

[0405] Optionally, if the PRACH occasion is a non-additional PRACH occasion (e.g., the second RO or a non-additional RO or a default RO), or the PRACH occasion is an additional PRACH occasion (if configured) and one time instance does not include PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) that is frequency division multiplexed on the same uplink carrier (e.g., NUL carrier or SUL carrier) as the additional PRACH occasion , M_RA2 is equal to zero; otherwise, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured).

[0406] Optionally, if the PRACH occasion is a non-additional PRACH occasion (e.g., the second RO or a non-additional RO or a default RO), or the PRACH occasion is an additional PRACH occasion (if configured), one time instance does not include both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., a second RO or non-additional RO or a default RO) for transmitting a random access preamble, M_RA2 is equal to zero; otherwise, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured).

[0407] Optionally, if the PRACH occasion is a non-additional PRACH occasion (e.g., the second RO or a non-additional RO or a default RO), or the PRACH occasion is an additional PRACH occasion (e.g., the first RO) (if configured) , and both the additional PRACH occasion (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or a non-additional RO or a default RO) for transmitting the random access preamble are not included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance, M_RA2 is equal to zero; otherwise, M_RA2 is equal to the higher layer parameter msgA-RO-FDM (if configured).

[0408] The method for determining the MSGB-RNTI associated with the first ROs used for transmitting the random access preamble which is presented in the embodiment of the present disclosure can effectively avoid the problem of MSGB-RNTI conflicts caused by the first RO and the second RO having the same frequency resource (or frequency domain) index when the first RO and the second RO are frequency-division multiplexed, reduce the probability of random access conflicts, and improve the performance of random access.

[0409] In an embodiment of the present disclosure, there is also provided a method for frequency resource indexes or frequency domain numbers associated with first random access resources (e.g., the first ROs), which may be applied to a four-step or two-step random access scenario, wherein the determined frequency resource indexes or frequency domain numbers may be used to calculate an RA-RNTI associated with the first RO for transmitting a random access preamble.

[0410] In an optional implementation, the random access preamble may be transmitted in a frequency resource specified by a higher layer parameter msg1-FrequencyStart or msg1-FrequencyStart2 or msgA-RO-FrequencyStart or msgA-RO-FrequencyStart2 (if configured), wherein the msg1-FrequencyStart is an offset of the lowest PRACH transmission occasion (e.g., the second RO) in the frequency domain with respect to PRB 0, for determining a frequency start (location) of the second RO; the msg1-FrequencyStart2 is an offset of the lowest additional PRACH transmission occasion (e.g., the first RO) in the frequency domain with respect to PRB 0, for determining a frequency start (location) of the first RO; the msgA-RO-FrequencyStart is an offset of the lowest PRACH transmission occasion (e.g., the second RO) in the frequency domain with respect to PRB 0, for determining a frequency start (location) of the second RO related to the two-step random access; and the msgA-RO-FrequencyStart2 is an offset of the lowest PRACH transmission occasion (e.g., the first RO) in the frequency domain with respect to PRB 0, for determining a frequency start (location) of the first RO related to the two-step random access.

[0411] When the PRACH frequency resources are additional PRACH frequency resources (e.g., the first random access resources, if configured), if one time instance includes additional PRACH occasion(s) (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or the non-additional or the default RO) that are frequency-division multiplexed (for transmission of the random access preamble); or,

[0412] if one time instance includes additional PRACH occasion(s) (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or the non-additional RO or the default RO) that are frequency-division multiplexed (for transmission of the random access preamble), and the additional PRACH occasion(s) and the PRACH occasion(s) are on the same UL carrier used for transmitting the random access preamble (e.g., the NUL carrier or the SUL carrier) ; or

[0413] if one time instance includes both additional PRACH occasion(s) (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or the non-additional RO or the default RO) for transmitting the random access preamble; or

[0414] if both additional PRACH occasion(s) (e.g., the first RO) and PRACH occasion(s) (e.g., the second RO or the non-additional RO or the default RO) for transmitting the random access preamble are included on an uplink carrier (e.g., the NUL carrier or the SUL carrier) in one time instance,

[0415] the PRACH frequency resources n_RA∈{msg1-FDM,msg1-FDM+1,...,M-1} (e.g., for the four-step random access scenario) are incrementally indexed starting from the lowest frequency in an initial uplink bandwidth part (initial UL BWP) during initial access. Otherwise, the incremental indexing starts at the lowest frequency in an active uplink bandwidth part (active UL BWP), where the higher layer parameter msg1-FDM is the number of frequency division multiplexed PRACH transmission occasions (e.g., the second ROs) in one time instance, and M is equal to the higher layer parameter msg1-FDMTotal, and if configured, msg1-FDMTotal is a total number of frequency division multiplexed PRACH transmission occasions in one time instance (e.g., including the Frequency division multiplexed PRACH occasion and additional PRACH occasion); and / or, M may be the maximum value of the number of frequency domain ROs (e.g., equal to the maximum value of the number of second frequency domain ROs, e.g., 8); and / or,

[0416] the PRACH frequency resources n_RA∈{msgA-RO-FDM,msgA-RO-FDM+1,...,M-1} (e.g., for the two-step random access scenario), are incrementally indexed starting with the lowest frequency in the initial uplink bandwidth part during initial access. Otherwise, the incremental indexing starts at the lowest frequency in an active UL BWP, where the higher layer parameter msgA-RO-FDM is the number of frequency division multiplexed PRACH transmission occasions (e.g., the second ROs) in one time instance for two-step random access, and M is equal to the higher layer parameter msg1-FDMTotal, and if configured, msg1-FDMTotal is a total number of frequency division multiplexed PRACH transmission occasions in one time instance (e.g., including the Frequency division multiplexed PRACH occasion(s) and additional PRACH occasion(s)); and / or, M may be the maximum value of the number of frequency domain ROs (e.g., equal to the maximum value of the number of second frequency domain ROs, e.g., 8). For example, FIG. 5b gives an example in which there are a total of 6 random access resources ROs in one time instance, including 4 first ROs and 2 second ROs, where frequency resource indexes of the second ROs are incrementally indexed from 0, i.e., 0, 1; for the first ROs, the frequency start location of the first random access resources is determined based on the lowest frequency start of the initial uplink bandwidth part or the active uplink bandwidth part as well as the higher layer parameter msg1-FrequencyStart2, and frequency resource indexes of the first ROs are incrementally indexed from 2, i.e., 2, 3, 4, 5, that is, the lowest frequency resource index of the first ROs is 2 (2 is the number of the second ROs in the frequency domain).

[0417] Otherwise, the PRACH frequency resources n_RA∈{0,1,...,M-1} are incrementally indexed starting from the lowest frequency in the initial uplink bandwidth part during initial access. Otherwise, the incremental indexing starts at the lowest frequency in an active uplink bandwidth part, where M is equal to the higher layer parameter msg1-FDM2 or msgA-RO-FDM2 (msg1-FDM2 is the number of additional frequency division multiplexed PRACH transmission occasions (e.g., the first ROs) in one time instance, and msgA-RO-FDM2 is the number of additional frequency division multiplexed PRACH transmission occasions (e.g., the first ROs) in one time instance for two-step random access); and / or, M may be determined based on the higher layer parameter msg1-FDM or msgA-RO-FDM and the maximum value of the number of ROs in the frequency domain (which may be equal to the maximum value of the number of the second ROs in the frequency domain, e.g., 8), and, specifically, M may be equal to a difference between the maximum value of the number of ROs in the frequency domain and the maximum value of msg1-FDM or msgA-RO-FDM (e.g., M=the maximum value of the number of ROs in the frequency domain - msg1-FDM or M=the maximum value of the number of ROs in the frequency domain - msgA-RO-FDM), wherein msg1-FDM is the number of frequency division multiplexed PRACH transmission occasions (e.g., the second ROs) in one time instance, and msgA-RO-FDM is the number of the frequency division multiplexed PRACH transmission occasions (e.g., the second ROs) in one time instance for two-step random access.

[0418] When the PRACH frequency resources are normal PRACH resources (i.e., when the PRACH frequency resources are not additional PRACH frequency resources, e.g., when the PRACH frequency resources are the second random access resources, if configured), the PRACH frequency resources n_RA∈{0,1,...,M-1} are incrementally indexed starting from the lowest frequency in the initial uplink bandwidth part during initial access; otherwise, they are incrementally indexed starting from the lowest frequency in the active uplink bandwidth part, where M is equal to the higher layer parameter msg1-FDM or msgA-RO-FDM (if configured).

[0419] The method for determining frequency resource indexes or numbers of the first ROs used for transmitting the random access preamble which is presented in the embodiment of the present disclosure can effectively avoid the problem of RA-RNTI or MSGB-RNTI conflicts caused by the first RO and the second RO having the same frequency resource (or frequency domain) index when the first RO and the second RO are frequency-division multiplexed, reduce the probability of random access conflicts, and improve the performance of random access.

[0420] An embodiment of the present disclosure provides another method performed by a UE in a communication system. As shown in FIG. 12, the method comprises S1210, S1220, S1230, etc. It should be noted that at least one of the above operations may be omitted, or, alternatively, additional operations may be included, e.g., one or more operations of the method described according to the embodiment of the present disclosure.

[0421] In step S1210, the UE receives first information, the first information being used to indicate first random access resources.

[0422] Optionally, the specific performance of step S1210 may be found in the description of step S410 and will not be repeated herein.

[0423] In step S1220, the UE transmits a preamble on a first uplink resource, the first uplink resource is determined based on the first random access resources indicated by the first information.

[0424] Optionally, the specific performance of step S1220 may be found in the description of step S420 and will not be repeated herein.

[0425] In step S1230, if the UE receives first downlink control information in a second time window, the second time window is stopped and a preamble is transmitted on a second uplink resource, the second uplink resource is determined based on the first downlink control information, the transmission power for the preamble is related to a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information.

[0426] Optionally, if the UE satisfies the above conditions (e.g., the first condition), the UE may carry out PRACH transmission (retransmission) based on a higher layer indication, wherein the power of the PRACH transmission (the transmitted preamble) is determined based on the first downlink control information.

[0427] For example, the UE may stop the second time window and transmit the preamble on the second uplink resource, in a case that the first random access resources indicated by the first information are different from the first random access resources indicated by the first downlink control information.

[0428] For another example, the UE stops the second time window and transmits the preamble on the second uplink resource, in a case that a second random access radio network temporary identifier (RA-RNTI) is different from a third RA-RNTI, wherein the second RA-RNTI is determined based on the first uplink resource and the third RA-RNTI is determined based on the second uplink resource.

[0429] For yet another example, the UE may stop the second time window and transmit the preamble on the second uplink resource in the case that at least one of the following is satisfied: the PDCCH is not monitored; and / or, the PDCCH is monitored, but the least significant bit (LSB) of a system frame number (SFN) field of the monitored PDCCH is different from a corresponding LSB of an SFN of the first uplink resource.

[0430] It can be understood that similar conditions (e.g., the first condition) as described above may also apply to the embodiments of the present disclosure, and the non-exhaustive description may be found in the introduction above and will not be repeated herein.

[0431] In the embodiment of the present disclosure, the transmission time of the retransmitted preamble may be determined based on a time associated with the reception of the first downlink control information and a fixed time interval preset by the protocol.

[0432] Optionally, an interval between a transmission time of transmitting the preamble on the second uplink resource and an end time of the second time window is greater than a second time interval, the second time interval being preset and / or determined based on a capability of the UE.

[0433] In the embodiment of the present disclosure, in step S1230, the UE may transmit a preamble based on first transmission power, the first transmission power is determined based on a first power step, the first power step is determined by the first downlink control information.

[0434] Specifically, if the UE determines that the first ROs are activated or deactivated based on the first downlink control information, the UE may determine a power step of the transmitted preamble based on a number of frequency domain resources of the activated or deactivated first ROs and / or a number of time domain resources of the first ROs, where the power step is a power step that the UE increases the power when it performs re-transmission of the preamble on the first ROs.

[0435] The power step may be associated with the number of frequency domain resources of the activated first ROs and / or the number of time domain resources of the first ROs as indicated according to the first downlink control information, the association may be configured or may be preset.

[0436] Optionally, the transmission power for transmitting the preamble on the second uplink resource is determined based on a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information and at least one threshold.

[0437] As an example, the number of frequency-domain and / or time-domain resources of the activated first ROs determined based on the first downlink control information is N, and a threshold related to the number of the activated first ROs is Nr, wherein Nr is configured by higher layer signaling or is preset by the protocol, thus:

[0438] when N is less than or equal to Nr, the power step is P1; otherwise, the power step is P2, where P1>P2; or,

[0439] when N is less than Nr, the power step is P1; otherwise, the power step is P2, where P1>P2; or,

[0440] when N is large than Nr, the power step is P1; otherwise, the power step is P2, where P1<P2; or,

[0441] when N is large than or equal to Nr, the power step is P1; otherwise, the power step is P2, where P1<P2;

[0442] wherein the units of P1 and P2 may be dB, and N and Nr are integers greater than 0.

[0443] As another example, the number of frequency-domain and / or time-domain resources of the activated first ROs and the power step may be associated in such a way that when the number of frequency-domain and / or time-domain resources of the activated first ROs is less than N4, the power step associated therewith is P1; when the number of frequency-domain and / or time-domain resources of the activated first ROs is greater than or equal to N4 and less than N5, the power step associated therewith is P2; and so on, when the number of frequency-domain and / or time-domain resources of the activated first ROs is greater than or equal to N_L-1 and less than N_L, the power step associated therewith is P_L, where L=1,2,3,..., N4<N5<...<N_L-1<N_L; the associated configuration may be notified via higher layer signaling or may be preset. For example, when the number of frequency-domain and / or time-domain resources of the activated first ROs is M2, the power step is P1 for M2<N4, the power step is P2 for N4≤M2<N5, and the power step is PL for N_L-1≤M<N_L.

[0444] Based on at least one of the embodiments above, in an embodiment of the present disclosure, the UE may determine whether or not to retransmit the preamble based on the random access response (msg2), and specifically, the random access response comprises a response indication information, the response indication information is used to indicate an index of an RO which is a response respective to the random access response. The advantage is that the UE may be prevented from receiving an erroneous random access response due to RA-RNTI conflicts, thus increase the success rate of random access of the UE, reduce the random access latency, and, furthermore, reuse an existing RA-RNTI, thereby reduce the complexity due to calculating or managing a new RA-RNTI.

[0445] The response indication information may be a PRACH mask that indicates the first ROs associated with one or more SSB indexes which are activated or deactivated among the first ROs, for example the PRACH mask may be used to indicate that all of the first ROs are available, or that even-numbered first ROs are available, or that odd-numbered first ROs are available, or that the first RO with a number of x is available (where a range of the number x is determined based on a frequency resource index range of the first ROs, and may be for example from 0 to M1-1, where M1 is a number of the first ROs used for frequency division multiplexing (FDM) for the first random access).

[0446] Based on at least one of the embodiments above, in an embodiment of the present disclosure, if it is satisfied that the UE repeatedly transmits the preamble on the first ROs more than H times consecutively, the UE re-transmits the preamble on the second ROs, wherein H may be obtained by a threshold of the number of preambles to be transmitted in configuration information related to random access, which is advantageous in avoiding that the UE fails to determine a suitable random access resource (e.g., the activated first ROs) due to the failure of the UE to receive the first downlink control information where the problem of random access failure occurs, and reducing the higher random access latency caused by the UE.

[0447] In an embodiment of the present disclosure, frequency resource indexes of the first random access resources are determined based on at least one of:

[0448] a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources;

[0449] a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources;

[0450] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources;

[0451] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; or

[0452] the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0453] For example, a minimum frequency resource index of the first random access resources is greater than a maximum frequency resource index of the second random access resources, the maximum frequency resource index of the second random access resources is determined based on the number of frequency domain resources of the second random access resources, and the first random access frequency resource indexes are in ascending order of frequencies from low to high, based on the number of frequency domain resources of the first random access resources, starting from the frequency start location of the first random access resources.

[0454] For another example, the first random access frequency resource indexes are determined based on the following formula:

[0455]

[0456] where denotes a frequency-domain resource index of the first random access resources, denotes the number of frequency domain resources of the first random access resources, denotes the total number of frequency domain resources, and denotes a modulo operation.

[0457] Alternatively, the first information indicates that the first random access resources are activated and / or deactivated, the frequency resource indexes of the activated first random access resources is determined based on at least one of:

[0458] a frequency start location of the activated first random access resources and a number of frequency domain resources of the activated first random access resources;

[0459] a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the activated first random access resources;

[0460] the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and the number of frequency domain resources of the second random access resources;

[0461] the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and a total number of frequency domain resources of the random access resources; or

[0462] the frequency start location of the activated first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0463] The non-exhaustive description of the method of determining the first random access frequency resource indexes may be found in the introduction above, and will not be repeated herein.

[0464] In an embodiment of the present disclosure, the method of determining the first uplink resource may comprise: the first uplink resource is a first available first random access resource among the activated first random access resources; and / or, the first uplink resource is selected from the configured second random access resources and the activated first random access resources in accordance with a first criterion; and / or, the first uplink resource is a first available random access resource among the second random access resources and the activated first random access resources; wherein the first criterion comprises at least one of:

[0465] if the second random access resources and the activated first random access resources are time-division multiplexed, the first uplink resource is the first available random access resource among the second random access resources and the activated first random access resources; or

[0466] if the second random access resources and the activated first random access resources are frequency-division multiplexed, the first uplink resource is the first available first random access resource among the activated first random access resources.

[0467] The non-exhaustive description of the method of determining the first uplink resource may be found in the introduction above, and will not be repeated herein.

[0468] In an embodiment of the present disclosure, the first information comprises at least one of: mask information for mapping of SSBs to the activated first random access resources; a period index for mapping of SSBs to the activated first random access resources; a physical random access channel (PRACH) association pattern period index; at least one fourth RA-RNTI; a reference fourth RA-RNTI and a number of the fourth RA-RNTIs; a frequency unit index; or a time unit index. Optionally, the first information comprises random access related configuration information and / or downlink control information. The non-exhaustive description of the first information and / or the first downlink control information may be found in the introduction above and will not be repeated herein.

[0469] An embodiment of the present disclosure provides yet another method performed by a UE in a communication system, the method comprises:

[0470] receiving first configuration information related to a first random access and second configuration information related to a second random access, wherein the first configuration information is related to a second feature;

[0471] transmitting a preamble on a first uplink resource, the first uplink resource being determined based on the first configuration information; and

[0472] monitoring a physical downlink control channel (PDCCH) for receiving a random access response based on a second random access radio network temporary identifier (RA-RNTI), the second RA-RNTI is determined based on the first configuration information and the second configuration information or determined based on the first configuration information.

[0473] The description of the first configuration information, the second configuration information, the second feature and the second RA-RNTI may be found above and will not be repeated herein.

[0474] Optionally, the second RA-RNTI is determined based on random access resource related information of the first uplink resource, the random access resource related information is used to indicate whether the first uplink resource is related to a second feature.

[0475] Optionally, the method further comprises: receiving second downlink control information, the second downlink control information is used to indicate the first random access resource, the first uplink resource is determined based on the first configuration information and the second downlink control information.

[0476] Optionally, frequency resource indexes of the first random access resources are determined based on at least one of:

[0477] a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources;

[0478] a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources;

[0479] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources;

[0480] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; or

[0481] the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0482] Optionally, the method further comprises: if first downlink control information is received in a second time window, monitoring a physical downlink control channel (PDCCH) for receiving a random access response based on a first random access radio network temporary identifier (RA-RNTI) in the second time window, wherein the first downlink control information is used to indicate the first random access resources, and the first RA-RNTI is determined based on the first uplink resource and the first downlink control information.

[0483] The non-exhaustive description of the embodiments of the present disclosure may be found in the introduction above and will not be repeated herein.

[0484] In an embodiment of the present disclosure, a schematic diagram of the 4-step random access procedure is shown in FIG. 13. For example, the contention-based random access procedure is divided into four steps. In step 1, the UE randomly selects a preamble from a pool of preamble resources and transmits it to the base station. The base station performs correlation detection on the received signal to recognize the preamble transmitted by the UE. In step 2, the base station transmits a random access response (RAR) to the UE. The RAR may comprise a random access preamble identifier, a timing advance instruction determined based on a latency estimation between the UE and the base station, a temporary cell-radio network temporary identifier (C-RNTI), and / or time-frequency resources allocated for the UE's next uplink transmission (the time-and-frequency resources may refer to time-domain resources and / or frequency-domain resources). The UE will search for a PDCCH carrying the feedback based on a RA-RNTI associated with a PRACH occasion(s) for transmitting the random access preamble. In step 3, the UE transmits a third message (Message 3, Msg3) to the base station based on the information in the RAR. The Msg3 contains information such as a user terminal identifier and an RRC link request, where the user terminal identifier is unique to the UE and is used for conflict resolution. In step 4, the base station transmits a conflict resolution identifier to the UE which contains the user terminal identifier that wins in conflict resolution. The UE, after detecting his / her own identity, upgrades the temporary C-RNTI to the C-RNTI and transmits an acknowledge character (ACK) signal to the base station, to complete the random access procedure and wait for scheduling by the base station. Otherwise, the UE will start a new random access procedure after a period of delay.

[0485] For contention-free random access procedure, since the base station has known the user identity, it may allocate a preamble to the UE. Therefore, instead of randomly selecting a sequence, the UE will use an allocated preamble when transmitting the preamble. After detecting the allocated preamble, the base station transmits a corresponding random access response, including information such as timing advance and uplink resource allocation. After receiving the random access response, the UE considers that the uplink synchronization has been completed and waits for further scheduling by the base station. Therefore, the contention-free random access procedure comprises only two steps: step 1 is transmitting the preamble; and step 2 is transmitting the random access response.

[0486] The random access method of the embodiment of the present disclosure may be used for the four-step or two-step random access procedure described above. However, it is not limited thereto and may be expanded or replaced with random access configurations for other features.

[0487] Optionally, the random access procedure of the embodiment of the present disclosure may be applied to the following scenarios:

[0488] 1. initial access in an idle state (RRC_IDLE);

[0489] 2. re-establishment of RRC connection;

[0490] 3. cell handover;

[0491] 4. downlink data arrival and request for random access procedure in a RRC connection state (when the uplink is in non-synchronization);

[0492] 5. uplink data arrival and request for random access procedure in a RRC connection state (when the uplink is in non-synchronization or no resources are allocated to the scheduling request in the PUCCH resources); and / or

[0493] 6. localization.

[0494] An embodiment of the present disclosure also provides a method performed by a base station in a communication system, the method comprises:

[0495] transmitting first information, the first information being used to indicate first random access resources;

[0496] receiving a preamble transmitted by a user equipment (UE), the preamble being transmitted on a first uplink resource, the first uplink resource being determined by the UE based on the first random access resources indicated by the first information;

[0497] transmitting first downlink control information, the first downlink control information being used to indicate the first random access resources; and

[0498] transmitting a physical downlink control channel (PDCCH) for transmitting a random access response based on a first random access radio network temporary identifier (RA-RNTI), the first RA-RNTI being determined based on the first uplink resource and the first downlink control information.

[0499] Optionally, the first RA-RNTI is determined based on at least one of:

[0500] the first uplink resource and the first random access resources indicated by the first downlink control information;

[0501] a frequency resource index of the first uplink resource and a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information;

[0502] the frequency resource index of the first uplink resource and a number of frequency domain resources respective to the first random access resources indicated by the first information;

[0503] the frequency resource index of the first uplink resource, the number of frequency domain resources respective to the first random access resources indicated by the first downlink control information, and the number of frequency domain resources respective to the first random access resources indicated by the first information; or

[0504] a number of frequency domain resources respective to configured second random access resources.

[0505] Optionally, the first RA-RNTI is determined based on random access resource related information of the first uplink resource, the random access resource related information being used to indicate whether the first uplink resource is related to a second feature.

[0506] Optionally, frequency resource indexes of the first random access resources are determined based on at least one of:

[0507] a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources;

[0508] a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources;

[0509] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources;

[0510] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; or

[0511] the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0512] Optionally, a minimum frequency resource index of the first random access resources is greater than a maximum frequency resource index of the second random access resources, the maximum frequency resource index of the second random access resources is determined based on the number of frequency domain resources of the second random access resources, and the first random access frequency resource indexes are in ascending order of frequencies from low to high, based on the number of frequency domain resources of the first random access resources, starting from the frequency start location of the first random access resources.

[0513] Optionally, the first random access frequency resource indexes are determined based on the following formula:

[0514]

[0515] where denotes a frequency-domain resource index of the first random access resources, denotes the number of frequency domain resources of the first random access resources, denotes the total number of frequency domain resources, and denotes a modulo operation.

[0516] Optionally, the first information indicates that the first random access resources are activated and / or deactivated, the frequency resource indexes of the activated first random access resources being determined based on at least one of:

[0517] a frequency start location of the activated first random access resources and a number of frequency domain resources of the activated first random access resources;

[0518] a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the activated first random access resources;

[0519] the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and the number of frequency domain resources of the second random access resources;

[0520] the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and a total number of frequency domain resources of the random access resources; or

[0521] the frequency start location of the activated first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0522] Optionally, the first information indicates that the first random access resources are activated and / or deactivated,

[0523] the first uplink resource is a first available first random access resource among the activated first random access resources; and / or, the first uplink resource is selected from the configured second random access resources and the activated first random access resources in accordance with a first criterion; and / or, the first uplink resource is a first available random access resource among the second random access resources and the activated first random access resources;

[0524] wherein the first criterion comprises at least one of:

[0525] if the second random access resources and the activated first random access resources are time-division multiplexed, the first uplink resource is the first available random access resource among the second random access resources and the activated first random access resources; or

[0526] if the second random access resources and the activated first random access resources are frequency-division multiplexed, the first uplink resource is the first available first random access resource among the activated first random access resources.

[0527] Optionally, the first information and / or the first downlink control information comprises at least one of:

[0528] mask information for mapping of synchronization signal blocks (SSBs) to the activated first random access resources;

[0529] a period index for mapping of SSBs to the activated first random access resources;

[0530] a physical random access channel (PRACH) association period index;

[0531] a PRACH association pattern period index;

[0532] at least one fourth RA-RNTI;

[0533] a reference fourth RA-RNTI and a number of the fourth RA-RNTIs;

[0534] a frequency unit index; or

[0535] a time unit index.

[0536] Optionally, the first information comprises random access related configuration information and / or downlink control information.

[0537] An embodiment of the present disclosure also provides a method performed by a base station in a communication system, the method comprises:

[0538] transmitting first information, the first information being used to indicate first random access resources;

[0539] receiving a preamble transmitted by a user equipment (UE), the preamble being transmitted on a first uplink resource, the first uplink resource being determined by the UE based on the first random access resources indicated by the first information;

[0540] transmitting first downlink control information, the first downlink control information being used to indicate the first random access resources; and

[0541] receiving a preamble transmitted by the UE, the preamble being transmitted on a second uplink resource, the second uplink resource being determined based on the first downlink control information, the received power of the preamble being related to a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information.

[0542] Optionally, an interval between a transmission time of transmitting the preamble on the second uplink resource and an end time of the second time window is greater than a second time interval, the second time interval being preset and / or determined based on a capability of the UE.

[0543] Optionally, the transmission power for transmitting the preamble on the second uplink resource by the UE is determined based on a number of frequency domain resources respective to the first random access resources indicated by the first downlink control information and at least one threshold.

[0544] Optionally, frequency resource indexes of the first random access resources are determined based on at least one of:

[0545] a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources;

[0546] a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources;

[0547] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources;

[0548] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; or

[0549] the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0550] Optionally, a minimum frequency resource index of the first random access resources is greater than a maximum frequency resource index of the second random access resources, the maximum frequency resource index of the second random access resources is determined based on the number of frequency domain resources of the second random access resources, and the first random access frequency resource indexes are in ascending order of frequencies from low to high, based on the number of frequency domain resources of the first random access resources, starting from the frequency start location of the first random access resources.

[0551] Optionally, the first random access frequency resource indexes are determined based on the following formula:

[0552]

[0553] where denotes a frequency-domain resource index of the first random access resources, denotes the number of frequency domain resources of the first random access resources, denotes the total number of frequency domain resources, and denotes a modulo operation.

[0554] Optionally, the first information indicates that the first random access resources are activated and / or deactivated, the activated first random access frequency resource indexes being determined based on at least one of:

[0555] a frequency start location of the activated first random access resources and a number of frequency domain resources of the activated first random access resources;

[0556] a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the activated first random access resources;

[0557] the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and the number of frequency domain resources of the second random access resources;

[0558] the frequency start location of the activated first random access resources, the number of frequency domain resources of the activated first random access resources, and a total number of frequency domain resources of the random access resources; or

[0559] the frequency start location of the activated first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0560] Optionally, the first information indicates that the first random access resources are activated and / or deactivated,

[0561] the first uplink resource is a first available first random access resource among the activated first random access resources; and / or, the first uplink resource is selected from the configured second random access resources and the activated first random access resources in accordance with a first criterion; and / or, the first uplink resource is a first available random access resource among the second random access resources and the activated first random access resources;

[0562] wherein the first criterion comprises at least one of:

[0563] if the second random access resources and the activated first random access resources are time-division multiplexed, the first uplink resource is the first available random access resource among the second random access resources and the activated first random access resources; or

[0564] if the second random access resources and the activated first random access resources are frequency-division multiplexed, the first uplink resource is the first available first random access resource among the activated first random access resources.

[0565] Optionally, the first information and / or the first downlink control information comprises at least one of:

[0566] mask information for mapping of synchronization signal blocks (SSBs) to the activated first random access resources;

[0567] a period index for mapping of SSBs to the activated first random access resources;

[0568] a physical random access channel (PRACH) association period index;

[0569] a PRACH association pattern period index;

[0570] at least one fourth RA-RNTI;

[0571] a reference fourth RA-RNTI and a number of the fourth RA-RNTIs;

[0572] a frequency unit index; or

[0573] a time unit index.

[0574] Optionally, the first information comprises random access related configuration information and / or downlink control information.

[0575] According to a further aspect of embodiments of the present disclosure, there is also provided a method performed by a base station in a communication system, the method comprises:

[0576] transmitting first configuration information related to a first random access and second configuration information related to a second random access, wherein the first configuration information is related to a second feature;

[0577] monitoring a preamble transmitted by a user equipment (UE), the preamble being transmitted on a first uplink resource, the first uplink resource being determined based on the first configuration information; and

[0578] transmitting a physical downlink control channel (PDCCH) for transmitting a random access response based on a second random access radio network temporary identifier (RA-RNTI), the second RA-RNTI being determined based on the first configuration information and the second configuration information or determined based on the first configuration information.

[0579] Optionally, the second RA-RNTI is determined based on random access resource related information of the first uplink resource, the random access resource related information being used to indicate whether the first uplink resource is related to a second feature.

[0580] Optionally, the method further comprises: transmitting second downlink control information, the second downlink control information being used to indicate the first random access resource, the first uplink resource being determined based on the first configuration information and the second downlink control information.

[0581] Optionally, the first random access frequency resource indexes are determined based on at least one of:

[0582] a frequency start location of the first random access resources and a number of frequency domain resources of the first random access resources;

[0583] a frequency start location of the configured second random access resources, a number of frequency domain resources of the second random access resources, and the number of frequency domain resources of the first random access resources;

[0584] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and the number of frequency domain resources of the second random access resources;

[0585] the frequency start location of the first random access resources, the number of frequency domain resources of the first random access resources, and a total number of frequency domain resources of the random access resources; or

[0586] the frequency start location of the first random access resources, the number of frequency domain resources of the second random access resources, and the total number of frequency domain resources of the random access resources.

[0587] Optionally, the method further comprises: transmitting first downlink control information, the first downlink control information being used to indicate the first random access resources; and transmitting a physical downlink control channel (PDCCH) for transmitting a random access response based on a first random access radio network temporary identifier (RA-RNTI), the first RA-RNTI being determined based on the first uplink resource and the first downlink control information.

[0588] The steps of the method performed by a base station according to the embodiment of the present disclosure correspond to the steps of the method performed by a UE, which have similar implementation principles and have corresponding technical effects. For a detailed functional description of the method performed by the base station, the description in the method performed by the UE shown in the above may be referred to, and will not be repeatedly described herein.

[0589] An embodiment of the present disclosure provides an electronic device comprising a processor, and optionally further comprising a transceiver and / or a memory coupled to the processor, the processor being configured to perform the steps of the method according to any optional embodiment of the present disclosure. Optionally, the electronic device may refer to a UE, whereby the processor is configured to implement the steps of the respective method embodiments performed by the UE, the detailed functional description and beneficial effects resulting therefrom may be specifically described hereinabove in the respective method embodiments performed by the UE, and will not be repeatedly described herein. Optionally, the electronic device may refer to a base station, whereby the processor is configured to implement the steps of the respective method embodiments performed by the base station, the detailed functional descriptions and the beneficial effects resulting therefrom may be referred to hereinabove in the description of the respective method embodiment performed by the base station, and will not be repeatedly described herein. In practical applications, the UE or the base station may be understood as different network nodes.

[0590] An embodiment of the present disclosure further provides an electronic device, including at least one controller / processor, and optionally at least one transceiver coupled to the at least one controller / processor. The processor is configured to implement the method provided in any one of optional embodiments of the present disclosure.

[0591] FIG. 14 shows a schematic structure diagram of an electronic device to which the solution of the embodiment of the present disclosure is applied. As shown in FIG. 14, the electronic device 4000 shown in FIG. 14 may include a processor 4001 and a memory 4003. The processor 4001 is connected to the memory 4003, for example, through a bus 4002. Optionally, the electronic device 4000 may further include a transceiver 4004 that may be used for data exchange, for example, transmission and reception of data, between the electronic device and other electronic device. It should be noted that, in practical applications, the number of transceiver 4004 is not limited to one, and the structure of the electronic device 4000 does not constitute any limitations to the embodiments of the present disclosure. Optionally, the electronic device may be gNB, UE or other entities or node in communication networks.

[0592] The processor 4001 may be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), or a field programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute various exemplary logical blocks, modules and circuits described in connection with the present disclosure. The processor 4001 may also be a combination for realizing computing functions, for example, a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0593] The bus 4002 may include a path to transfer information between the components described above. The bus 4002 may be a peripheral component interconnect (PCI) bus, or an extended industry standard architecture (EISA) bus, etc. The bus 4002 may be an address bus, a data bus, a control bus, etc. For ease of presentation, the bus is represented by only one thick line in FIG. 14. However, it does not mean that there is only one bus or one type of buses.

[0594] The memory 4003 may be, but not limited to, read only memories (ROMs) or other types of static storage devices that may store static information and instructions, random access memories (RAMs) or other types of dynamic storage devices that may store information and instructions, may be electrically erasable programmable read only memories (EEPROMs), compact disc read only memories (CD-ROMs) or other optical disk storages, optical disc storages (including compact discs, laser discs, discs, digital versatile discs, blue-ray discs, etc.), magnetic storage media or other magnetic storage devices, or any other media that may carry or store desired program codes in the form of instructions or data structures and that may be accessed by computers.

[0595] The memory 4003 is used to store computer program for executing the solutions of the present disclosure, and is controlled by the processor 4001. The processor 4001 is used to execute the computer program stored in the memory 4003 to implement the solution provided in any method embodiment described above.

[0596] Embodiments of the present disclosure provide a computer-readable storage medium having a computer program stored on the computer-readable storage medium, the computer program, when executed by a processor, implements the steps and corresponding contents of the foregoing method embodiments.

[0597] Embodiments of the present disclosure also provide a computer program product including a computer program, the computer program when executed by a processor realizing the steps and corresponding contents of the preceding method embodiments.

[0598] The terms "first", "second", "third", "fourth", "1", "2", etc. (if present) in the specification and claims of this disclosure and the accompanying drawings above are used to distinguish similar objects and need not be used to describe a particular order or sequence. It should be understood that the data so used is interchangeable where appropriate so that embodiments of the present disclosure described herein may be implemented in an order other than that illustrated or described in the text.

[0599] It should be understood that while the flow diagrams of embodiments of the present disclosure indicate the individual operational steps by arrows, the order in which these steps are performed is not limited to the order indicated by the arrows. Unless explicitly stated herein, in some implementation scenarios of embodiments of the present disclosure, the implementation steps in the respective flowcharts may be performed in other orders as desired. In addition, some, or all of the steps in each flowchart may include multiple sub-steps or multiple phases based on the actual implementation scenario. Some or all of these sub-steps or stages may be executed at the same moment, and each of these sub-steps or stages may also be executed at different moments separately. The order of execution of these sub-steps or stages may be flexibly configured according to requirements in different scenarios of execution time, and the embodiments of the present disclosure are not limited thereto.

[0600] The above-mentioned description and the drawings are provided merely as examples to help readers to understand the present disclosure, and they should not be interpreted or aim to limit the scope of the present disclosure in any way. Although some embodiments are provided, it is apparent for those skilled in the art to adopt other similar implementation means based on the technical idea of the present disclosure without departing from the technical concept of the solution of the present disclosure.

Claims

1.A method performed by a user equipment (UE) in a wireless communication system, the method comprising:receiving, from a base station (BS), configuration information regarding a plurality of physical random access channel (PRACH) transmission occasions frequency-division multiplexed in one time instance, wherein the plurality of PRACH transmission occasions include a first PRACH transmission occasion that is a non-additional PRACH transmission occasion and a second PRACH transmission occasion that is an additional PRACH transmission occasion; anddetermining a minimum random access (RA) frequency resource index of the second PRACH transmission occasion to be greater than a maximum RA frequency resource index of the first PRACH transmission occasion,wherein the maximum RA frequency resource index of the first PRACH transmission occasion is determined based on a number of frequency resources for the first PRACH transmission occasion included in the configuration information.2.The method of claim 1,wherein the configuration information further includes a maximum number, M, of the first PRACH transmission occasion frequency-division multiplexed in one time instance.3.The method of claim 1, wherein a frequency start location of the first PRACH transmission occasion is determined based on the configuration information, andwherein a frequency start location of the second PRACH transmission occasion is determined based on the first PRACH transmission occasion.4.The method of claim 1,wherein RA frequency resource indexes of the second PRACH transmission occasion are numbered in an ascending order starting from a lowest frequency of the frequency resources for the second PRACH transmission occasion.5.The method of claim 1,wherein the configuration information further includes a number of frequency resources for the second PRACH transmission occasion.6.A user equipment (UE) in a wireless communication system, the UE comprising:a transceiver; andat least one processor coupled with the transceiver and configured to:receive, from a base station (BS), configuration information regarding a plurality of physical random access channel (PRACH) transmission occasions frequency-division multiplexed in one time instance, wherein the plurality of PRACH transmission occasions include a first PRACH transmission occasion that is a non-additional PRACH transmission occasion and a second PRACH transmission occasion that is an additional PRACH transmission occasion, anddetermine a minimum random access (RA) frequency resource index of the second PRACH transmission occasion to be greater than a maximum RA frequency resource index of the first PRACH transmission occasion,wherein the maximum RA frequency resource index of the first PRACH transmission occasion is determined based on a number of frequency resources for the first PRACH transmission occasion included in the configuration information.7.The UE of claim 6,wherein the configuration information further includes a maximum number, M, of the first PRACH transmission occasion frequency-division multiplexed in one time instance.8.The UE of claim 6, wherein a frequency start location of the first PRACH transmission occasion is determined based on the configuration information, andwherein a frequency start location of the second PRACH transmission occasion is determined based on the first PRACH transmission occasion.9.The UE of claim 6,wherein RA frequency resource indexes of the second PRACH transmission occasion are numbered in an ascending order starting from a lowest frequency of the frequency resources for the second PRACH transmission occasion.10.The UE of claim 6,wherein the configuration information further includes a number of frequency resources for the second PRACH transmission occasion.11.A method performed by a base station (BS) in a wireless communication system, the method comprising:transmitting, to a user equipment (UE), configuration information regarding a plurality of physical random access channel (PRACH) transmission occasions frequency-division multiplexed in one time instance, wherein the plurality of PRACH transmission occasions include a first PRACH transmission occasion that is a non-additional PRACH transmission occasion and a second PRACH transmission occasion that is an additional PRACH transmission occasion; andin case that a preamble for a random access (RA) is received from the UE, transmitting a random access response based on a RA-network temporary identifier (RNTI),wherein the RA-RNTI is determined based on a RA frequency resource index of the first PRACH transmission occasion or the second PRACH transmission occasion,a minimum RA frequency resource index of the second PRACH transmission occasion is determined to be greater than a maximum RA frequency resource index of the first PRACH transmission occasion, andthe maximum RA frequency resource index of the first PRACH transmission occasion is determined based on a number of frequency resources for the first PRACH transmission occasion included in the configuration information.12.The method of claim 11,wherein the configuration information further includes a maximum number, M, of the first PRACH transmission occasion frequency-division multiplexed in one time instance.13.The method of claim 11,wherein a frequency start location of the first PRACH transmission occasion is determined based on the configuration information, anda frequency start location of the second PRACH transmission occasion is determined based on the first PRACH transmission occasion.14.A base station (BS) in a wireless communication system, the BS comprising:a transceiver; andat least one processor coupled with the transceiver and configured to:transmit, to a user equipment (UE), configuration information regarding a plurality of physical random access channel (PRACH) transmission occasions frequency-division multiplexed in one time instance, wherein the plurality of PRACH transmission occasions include a first PRACH transmission occasion that is a non-additional PRACH transmission occasion and a second PRACH transmission occasion that is an additional PRACH transmission occasion, andin case that a preamble for a random access (RA) is received from the UE, transmit a random access response based on a RA-network temporary identifier (RNTI),wherein the RA-RNTI is determined based on a RA frequency resource index of the first PRACH transmission occasion or the second PRACH transmission occasion,a minimum RA frequency resource index of the second PRACH transmission occasion is determined to be greater than a maximum RA frequency resource index of the first PRACH transmission occasion, andthe maximum RA frequency resource index of the first PRACH transmission occasion is determined based on a number of frequency resources for the first PRACH transmission occasion included in the configuration information.15.The BS of claim 14,wherein the configuration information further includes a maximum number, M, of the first PRACH transmission occasion frequency-division multiplexed in one time instance.

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