Wireless terminal, wireless access network node, and methods thereof

Abstract

A wireless terminal (1) selects, from a plurality of beamformed beams, a beam having a reference signal received power (RSRP) greater than a first RSRP threshold associated with a selected, desired, or intended characteristic / combination of characteristics. The wireless terminal (1) transmits a random access preamble using a first random access resource corresponding to the selected beam. This can contribute to making the wireless terminal able to consider the characteristic and / or combination of characteristics when selecting a beam, for example.

Description

Technical Field

[0001] The present disclosure relates to wireless communication networks, and more particularly to random access.

Background Art

[0002] The 3rd Generation Partnership Project (3GPP™) Radio Access Network (RAN) Working Group is currently considering support for additional random access resource partitioning. This feature is planned to be introduced in 3GPP Release 17 (see, e.g., Non-Patent Documents 1-4). Random access resource partitioning partitions the random access resources used for random access preamble transmission. Random access resource partitioning enables a wireless terminal (e.g., User Equipment (UE)) to inform a radio access network node (e.g., gNB, eNB) of information by the resources used in random access preamble transmission.

[0003] In this specification, random access resources refer to random access preambles, or combinations of random access occasions and random access preambles. Random access resource partitioning is also referred to as Random Access Channel (RACH) resource partitioning or RACH partitioning. Random access occasions are also called RACH occasions (ROs), and random access preambles are also called RACH preambles. One RACH occasion is the time and frequency resources for RACH preamble transmission. According to the current 3GPP Release 15 and Release 16 specifications, one RACH occasion has a maximum of 64 RACH preambles available for transmission.

[0004] In the RACH partitioning of 3GPP Release 16, the UE can inform the gNB of the following information depending on which RACH preamble is used. - The selected Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) block (SSB) (or the selected beam) - Contention-Free Random Access (CFRA) or Contention-Based RA (CBRA) cause - Payload size (preamble group B configured or not) - Random access type (2-Step or 4-step RA)

[0005] To enable a network (e.g., gNB) to identify features earlier, further RACH partitioning is being considered for several Release 17 features. These features include, for example, Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CE or CovEnh), and Slicing. All RACH resource partitions resulting from possible feature combinations (or combinations of features) need to be configured. Possible feature combinations include, for example, RedCap+SDT, RedCap+CovEnh, RedCap+Slicing, RedCap+SDT+CovEnh, RedCap+SDT+Slicing, RedCap+CovEnh+Slicing, etc. Features may be referred to as functional features.

[0006] RedCap indication in RACH is used to show reduced capabilities to the network in the first RACH message (MSG1 in 4-step RA, MSGA in 2-step RA), enabling the network to adapt subsequent transmissions.

[0007] SDT indication in RACH is used to show SDT to the network and to request a larger third RACH message (MSG3) size. Alternatively, the SDT indication is used to indicate that in the case of 2-step RA, the MSGA size (the size of the data part of MSGA) is larger.

[0008] The CovEnh indication in RACH is used to indicate the need for coverage enhancement and is used, for example, for the repetition requirement of the 3rd RACH message (MSG3 in 4-step RA). The CovEnh indication may be binary information indicating whether Msg3 PUSCH repetition is required.

[0009] The Slicing indication in RACH indicates a network slice with high priority to the network and is used to achieve slice isolation for RACH. The Slicing indication may be binary information for distinguishing between prioritized and non-prioritized network slices. Alternatively, the Slicing indication may indicate multi-level slice priority, the selected or intended network slice, or the selected or intended network slice group, which will lead to a further increase in the number of partitions.

Prior Art Documents

Non-Patent Documents

[0010]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

[0011] The inventor of the present case studied random access resource partitioning for Release 17 features and feature combinations and found various problems.

[0012] One of these issues relates to SSB beam selection. According to the provisions of Release 15 and Release 16, at initial attach, the UE performs beam selection based on the Reference Signal Received Power (RSRP) threshold in random access resource selection. Specifically, the gNB transmits the sequence of SSB beams in different directions. The different beams transmitted by the gNB are associated (or mapped) with different SSBs or different SSB indices. The UE selects an SSB (or beam) with an SS-RSRP exceeding the RSRP threshold (i.e., rsrp-ThresholdSSB or msgA-RSRP-ThresholdSSB) from these multiple SSB beams. Subsequently, the UE starts transmitting a random access preamble using the RACH resources associated (or mapped) with the selected SSB (or SSB index). However, it is not clear how the new features or feature combinations introduced in Release 17 are considered in SSB (or beam) selection.

[0013] Another one of these issues relates to uplink carrier selection. According to the provisions of Release 15 and Release 16, the UE makes a selection between the Normal Uplink (NUL) carrier and the Supplementary Uplink (SUL) carrier prior to random access resource selection. If the UE has to perform random access resource selection considering features or feature combinations after making a selection between the NUL carrier and the SUL carrier, the network (e.g., gNB) may have to configure the same feature combinations on both the NUL carrier and the SUL carrier. In other words, the same feature combinations may have to be supported on both the NUL carrier and the SUL carrier. However, as described in Non-Patent Document 4, for example, carrier selection may not have to be supported for Coverage Enhancement. Therefore, it is not clear how to coordinate random access resource selection based on Release 17 features or feature combinations with the selection between the NUL carrier and the SUL carrier.

[0014] Yet another one of these issues relates to the fragmentation of random access resources. Generally, the number of random access resource partitions increases exponentially with the number of features. If a cell has to provide separate random access partitions for all Release 17 features and all possible feature combinations, the number of available random access resources (e.g., RACH preambles) within each partition may be very small. The previous discussions of the 3GPP RAN Working Group are not clear on how to address this problem.

[0015] One of the objectives to be achieved by the embodiments disclosed in this specification is to provide an apparatus, a method, and a program that contribute to solving at least one of a plurality of problems related to random access resource partitioning including the problems described above. It should be noted that this objective is only one of the plurality of objectives to be achieved by the plurality of embodiments disclosed in this specification. Other objectives or problems and novel features will be clarified from the description of this specification or the accompanying drawings.

Means for Solving the Problems

[0016] In a first aspect, the wireless terminal includes at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to select, from a plurality of beamformed beams, a beam having a Reference Signal Received Power (RSRP) exceeding a first RSRP threshold associated with a selected, desired, or intended feature or feature combination. The at least one processor is configured to perform a random access preamble transmission using a first random access resource corresponding to the selected beam. The feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing. The feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing.

[0017] In a second aspect, a method performed by a wireless terminal includes: (a) selecting, from a plurality of beamformed beams, a beam having a reference signal received power (RSRP) exceeding a first RSRP threshold associated with a selected, desired, or intended feature or feature combination; and (b) performing a random access preamble transmission using a first random access resource corresponding to the selected beam. The feature is RedCap, SDT, CovEnh, or Slicing. The feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing.

[0018] In a third aspect, a radio access network (RAN) node includes at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to broadcast, in a cell, a first RSRP threshold associated with a feature or feature combination. The first RSRP threshold is used by a wireless terminal to select, from a plurality of beamformed beams, a beam having an RSRP exceeding the first RSRP threshold and to perform a random access preamble transmission using a first random access resource corresponding to the selected beam. The feature is RedCap, SDT, CovEnh, or Slicing. The feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing.

[0019] In a fourth aspect, the method performed by the RAN node includes broadcasting, in a cell, a first RSRP threshold associated with a feature or a combination of features. The first RSRP threshold is used by a wireless terminal to select, from a plurality of beamformed beams, a beam having an RSRP exceeding the first RSRP threshold and perform a random access preamble transmission using a first random access resource corresponding to the selected beam. The feature is RedCap, SDT, CovEnh, or Slicing. The combination of features includes at least two of RedCap, SDT, CovEnh, and Slicing.

[0020] In a fifth aspect, a wireless terminal includes at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to select, based on downlink measurement results, one of the NUL carrier and the SUL carrier if both the Normal Uplink (NUL) carrier and the Supplementary Uplink (SUL) carrier support a selected, desired, or intended feature or combination of features, or otherwise select, from the NUL carrier and the SUL carrier, the one that supports the feature or the combination of features. The at least one processor is configured to perform a random access preamble transmission using a random access resource associated with the selected uplink carrier.

[0021] In a sixth aspect, the method performed by a wireless terminal includes the following steps: (a) If both the NUL carrier and the SUL carrier support a selected, desired, or intended feature or combination of features, select one of the NUL carrier and the SUL carrier based on downlink measurement results, or otherwise select, from the NUL carrier and the SUL carrier, the one that supports the feature or the combination of features, and (b) Performing a random access preamble transmission using the random access resource associated with the selected uplink carrier.

[0022] In a seventh aspect, the wireless terminal includes at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to select one of a NUL carrier and a SUL carrier as an uplink carrier based on downlink measurement results. The at least one processor is configured to perform a random access preamble transmission using a random access resource associated with a feature subset included in the feature combination if the selected uplink carrier does not support the selected, desired, or intended feature combination.

[0023] In an eighth aspect, the method performed by the wireless terminal includes the following steps: (a) Selecting one of a NUL carrier and a SUL carrier as an uplink carrier based on downlink measurement results, and (b) Performing a random access preamble transmission using a random access resource associated with a feature subset included in the feature combination if the selected uplink carrier does not support the selected, desired, or intended feature combination.

[0024] In a ninth aspect, a wireless terminal includes at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to perform a random access preamble transmission using a random access resource selected from a first set of random access resources associated with a selected, desired, or intended feature combination if the first set is configured. The at least one processor is configured to perform a random access preamble transmission using a random access resource selected from a second set of random access resources associated with a feature subset included in the feature combination if the first set is not configured.

[0025] In a tenth aspect, a method performed by a wireless terminal includes the following steps: (a) performing a random access preamble transmission using a random access resource selected from a first set of random access resources associated with a selected, desired, or intended feature combination if the first set is configured; and (b) performing a random access preamble transmission using a random access resource selected from a second set of random access resources associated with a feature subset included in the feature combination if the first set is not configured.

[0026] In the eleventh aspect, the wireless terminal includes at least one memory and at least one processor coupled to the at least one memory. If a first set of random access resources associated with a selected, desired, or intended feature or combination of features is set, the at least one processor is configured to perform a random access preamble transmission using a random access resource selected from the first set. If the first set is not set, the at least one processor is configured to perform a random access preamble transmission using a random access resource selected from a second set of random access resources not associated with the feature or the combination of features.

[0027] The twelfth aspect is directed to a program. The program includes a set of instructions (software code) for causing a computer to perform the method according to the second, fourth, sixth, eighth, tenth, or twelfth aspect described above when loaded into the computer.

Advantages of the Invention

[0028] According to the above aspects, an apparatus, a method, and a program can be provided that contribute to solving at least one of a plurality of problems related to random access resource partitioning.

Brief Description of the Drawings

[0029]

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Embodiments for Carrying Out the Invention

[0030] Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted as necessary for clarity of explanation.

[0031] The plurality of embodiments described below can be implemented independently or in appropriate combination. These plurality of embodiments have different novel features from each other. Therefore, these plurality of embodiments contribute to solving different objects or problems and to achieving different effects.

[0032] The plurality of embodiments shown below are mainly described with respect to the 3GPP 5th generation mobile communication system (5G system). However, these embodiments may be applied to other wireless communication systems.

[0033] As used herein, depending on the context, "(if) ~ then" may be construed to mean "when", "at or around the time", "after", "upon", "in response to determining", "in accordance with a determination", or "in response to detecting". These expressions may be construed to have the same meaning depending on the context.

[0034] First, the configuration and operation of a plurality of network elements common to multiple embodiments are described. FIG. 1 shows a configuration example of a wireless communication system according to multiple embodiments. In the example of FIG. 1, the wireless communication system includes a wireless terminal (i.e., UE) 1 and a radio access network (RAN) node (e.g., gNB) 2. Each element (network function) shown in FIG. 1 can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform.

[0035] UE1 has at least one wireless transceiver and is configured to perform cellular communication with RAN node 2. RAN node 2 manages cell 21 and is configured to perform cellular communication with a plurality of UEs including UE1 using a cellular communication technology (e.g., NR Radio Access Technology (RAT)).

[0036] RAN Node 2 may be a Central Unit (e.g., gNB-CU) in a cloud RAN (C-RAN) deployment, or a combination of a CU and one or more Distributed Units (e.g., gNB-DUs). C-RAN is also referred to as CU / DU split. Further, the CU may include a Control Plane (CP) Unit (e.g., gNB-CU-CP) and one or more User Plane (UP) Units (e.g., gNB-CU-UP). Thus, RAN Node 2 may be a CU-CP, or a combination of a CU-CP and a CU-UP. The CU may be a logical node that hosts the Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols of the gNB (or the RRC and PDCP protocols of the gNB). The DU may be a logical node that hosts the Radio Link Control (RLC), Medium Access Control (MAC), and Physical (PHY) layers of the gNB.

[0037] RAN node 2 transmits signals including System Information (SI) 101 and other signals within cell 21. System Information 101 includes a Master Information Block (MIB) and many System Information Blocks (SIBs). System Information 101 is divided into Minimum SI and Other SI. Minimum SI is always broadcast periodically and includes the basic information necessary for initial access and the information necessary to obtain other SI. Other SI includes all SIBs that are not broadcast within Minimum SI. More specifically, Minimum SI includes the MIB and SIB type 1 (SIB1), and Other SI includes SIB types after SIB type 2 (SIB2). Each SIB included in Other SI is either always broadcast periodically, broadcast on demand based on requests from UEs that are RRC_IDLE or RRC_INACTIVE, or sent to UEs that are RRC_CONNECTED via dedicated RRC signaling. If RAN node 2 is in a C-RAN configuration, a DU (e.g., gNB-DU) may generate at least a part of the system information (e.g., MIB, SIB1). The DU may directly transmit the generated system information to UE1, or may transmit it to a CU (e.g., gNB-CU) so that the CU can transmit this to UE1 (via the DU).

[0038] In the example of FIG. 1, UE1 selects or reselects cell 21 of RAN node 2 and camps on cell 21. In other words, cell 21 is the serving cell of UE1. The serving cell of UE1 can be said to be the cell on which UE1 camps. The serving cell may also be called a camped cell. A UE in RRC_IDLE or RRC_INACTIVE camps on a suitable cell if it can select a suitable cell to camp on according to the cell selection criteria or cell reselection criteria. Camping on a cell means that the UE has completed the cell selection or reselection process and has selected a cell. In other words, the term "camp on" means a state in which the UE stays on the cell and is ready to start potential dedicated services on that cell.

[0039] FIG. 2 shows an example of the protocol stack of the control plane of UE1. The control plane protocol stack 200 of UE1 includes an Application (APP) layer 201, a Non-Access Stratum (NAS) layer 202, and an Access Stratum (AS) 208 layer. The AS layer 208 includes an RRC layer 203, a PDCP layer 204, an RLC layer 205, a MAC layer 206, and a PHY layer 207.

[0040] The NAS layer 202 utilizes the data communication on the radio interface provided by the AS layer 208 and the management of the radio interface, and communicates with the core network (i.e., 5G Core (5GC)) via the RAN node 2 in accordance with the 5G System (5GS) Mobility Management (5GMM) protocol and the 5GS Session Management (5GSM) protocol. The 5GMM protocol is executed between the UE1 and the Access and Mobility Management Function (AMF) in the 5GC and is used for UE registration, mobility, and the transport of 5GSM protocol messages. The 5GSM protocol is executed between the UE1 and the Session Management Function (SMF) in the 5GC via the AMF and supports the management of PDU Session connectivity.

[0041] The NAS layer 202 communicates with the RRC layer 203 to utilize the services provided by the AS layer 208 (i.e., data communication on the radio interface between the UE1 and the RAN node 2 and the management of the radio interface). The RRC layer 203 is a lower layer of the NAS layer 202, provides radio resource control (RRC), and manages the RRC state of the UE1 (i.e., RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED).

[0042] The AS layer 208 initiates an RRC connection establishment procedure or an RRC connection resume procedure in response to a request from the NAS layer 202 or spontaneously. For example, upon receiving a PDU Session establishment request from an upper layer (i.e., the application layer 201), if the 5GS mobility management (5GMM) mode of UE1 is 5GMM-IDLE, the NAS layer 202 starts a registration procedure or a service request procedure to transition to the 5GMM-CONNECTED mode and attempts to send an initial NAS message (e.g., a registration request message or a service request message) to the AMF. The initial NAS message from the NAS layer 202 triggers the AS layer 208 to establish an RRC connection between UE1 and the RAN node 2. If the 5GMM mode is 5GMM-CONNECTED or 5GMM-CONNECTED with RRC inactive indication, the NAS layer 202 attempts to send a NAS message (e.g., a PDU SESSION ESTABLISHMENT REQUEST message, a UL NAS TRANSPORT message, a PDU SESSION MODIFICATION REQUEST, or a service request message) that depends on the event that triggered the access attempt. Alternatively, if the 5GMM mode is 5GMM-CONNECTED or 5GMM-CONNECTED with RRC inactive indication and the access attempt was "an uplink user data packet is to be sent for a PDU session with suspended user-plane resources", the NAS layer 202 requests the AS layer 208 to transition to RRC_CONNETED to send an uplink user data packet (Mobile Originated (MO) data).

[0043] In response to the reception of an initial NAS message or a request for a transition to RRC_CONNECTED, the RRC layer 203 requests or triggers the MAC layer 206 to initiate a random access procedure to send an RRC message for establishing or resuming an RRC connection (i.e., an RRC Setup Request message or an RRC Resume Request message). Prior to this, the RRC layer 203 may perform one or more access barring checks. If the access barring check is passed, the RRC layer 203 may request the MAC layer 206 to initiate a random access procedure. Techniques for access barring include, for example, Access Class Barring (ACB), Extended Access Barring (EAB), Application specific Congestion control for Data Communication (ACDC), and Unified Access Control (UAC). The RRC layer 203 may perform a barring check for one or more of these access barring techniques.

[0044] The MAC layer 206 receives a trigger for a random access procedure from the RRC layer 203 based on events such as re - establishment and resumption of an RRC connection, and initiates a random access procedure accordingly. The MAC layer 206 may initiate a random access procedure by itself or by a Physical Downlink Control Channel (PDCCH) order.

[0045] In the random access procedure, the MAC layer 206 selects one RACH resource from a set of partitioned random access resources (RACH resources) for use in transmitting the RACH preamble. The set of RACH resources includes RACH preambles, or combinations of RACH occasions and RACH preambles. One RACH occasion is the time and frequency resources for RACH preamble transmission. According to the current 3GPP Release 15 and Release 16 specifications, one RACH occasion has 64 RACH preambles available for transmission.

[0046] The MAC layer 206 requests the PHY layer 207 to transmit a random access preamble (RACH preamble) using the selected RACH resource. The random access procedure further includes receiving a Random Access Response (RAR) and contention resolution.

[0047] The MAC layer 206 may follow the RACH partitioning of 3GPP Release 16. In the RACH partitioning of 3GPP Release 16, the UE can inform the gNB of the following information depending on which RACH preamble is used. - The selected Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) block (SSB) (or the selected beam) - Contention-Free Random Access (CFRA) or Contention-Based RA (CBRA) cause - Payload size (preamble group B configured or not) - Random access type (2-Step or 4-step RA)

[0048] In addition, the MAC layer 206 supports additional RACH partitioning for Release 17 features. This enables the RAN node 2 to early identify the Release 17 features or feature combinations selected, desired, or intended by the UE1. For example, RACH resource partitions are set for each of all or a subset of the Release 17 features, and further RACH resource partitions are set for each of the possible feature combinations (or combinations of features). Each Release 17 feature is, for example, Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CE or CovEnh), or Slicing. The feature combinations include, for example, at least two of RedCap, SDT, CovEnh, and Slicing. The term "feature" used hereinafter in this specification means any of these Release 17 features unless otherwise specified. Similarly, the term "feature combination" means a combination composed of at least two of these Release 17 features unless otherwise specified. The "feature combination" may be referred to as a "feature set" or a "set of features".

[0049] RedCap indication in RACH is used to indicate reduced capabilities to the network in the first RACH message (MSG1 in 4-step RA, MSGA in 2-step RA), enabling the network to adapt subsequent transmissions. The 3GPP RAN Working Group is currently considering support for RedCap UEs over New Radio (NR), which is planned to be introduced in 3GPP Release 17. The introduction of RedCap NR devices enables support for use cases that are not yet optimally provided in the current NR standard. Use cases motivating the standardization of NR RedCap include wearables (e.g., smart watches, wearable medical devices, Augmented Reality (AR) / Virtual Reality (VR) goggles), industrial wireless sensors, and video surveillance. These use cases do not have as stringent data rate requirements as enhanced mobile broadband (eMBB) use cases and do not require tight or deterministic latency requirements like time-critical communications use cases. Therefore, there is room to trade off device capabilities for complexity or cost reduction compared to Release 15 NR devices as a baseline. According to the currently envisioned capabilities of RedCap devices, the maximum device bandwidth, the minimum number of device receive branches, the maximum number of downlink MIMO layers, and the maximum downlink modulation order may be reduced or relaxed compared to those of Release 15 NR devices.

[0050] The SDT indication in the RACH is used to indicate the SDT to the network and to request a larger third RACH message (MSG3) size. Alternatively, the SDT indication is used to indicate that in the case of 2-step RA, it is a larger MSGA size (the size of the data part of MSGA). Further, similar to the RACH in 3GPP Release 15 / 16, the size of MSG3 or MSGA may be of two types. In this case, the SDT indication in the RACH may further indicate the size of MSG3 or MSGA. SDT, also called SDT in inactive state, is one of the new features introduced in 3GPP Release 17. This enables UEs in the RRC_INACTIVE state to send infrequent and small data without requiring an RRC state transition.

[0051] The CovEnh indication in RACH is used to indicate the need for coverage enhancement and is used, for example, for the repetition request of the 3rd RACH message (MSG3 in 4-step RA). The CovEnh indication may be binary information indicating whether Msg3 PUSCH repetition is required. Alternatively, the CovEnh indication may indicate one of multiple coverage enhancement (CE) levels. The CovEnh indication may indicate one of two or more CE level groups (or CE modes). One CE level group or CE mode includes one or more CE levels. For example, the CE defined in 3GPP Release 14 supports up to 4 CE levels (i.e., CE levels 0 to 3). The UE determines the CE level based on the measured RSRP level. CE level 0 is associated with the highest RSRP threshold, and CE level 3 is associated with the lowest RSRP threshold. In other words, a UE at CE level 0 enjoys relatively low path loss and high downlink received power, and a UE at CE level 3 enjoys relatively high path loss and low downlink received power.

[0052] The Slicing indication in RACH indicates a network slice with high priority to the network and is used to achieve slice isolation for RACH. The Slicing indication may be binary information for distinguishing between prioritized and non-prioritized network slices. Alternatively, the Slicing indication may be information indicating one of three or more multi-level slice priorities. The Slicing indication may indicate the network slice selected or intended by UE1, or the selected or intended network slice group. The network slice group includes one or more network slices.

[0053] Network slicing enables the creation of multiple virtualized logical networks on top of a physical network using Network Function Virtualization (NFV) technology and software-defined networking (SDN) technology. Each virtualized logical network is called a network slice or network slice instance, includes logical nodes and functions, and is used for specific traffic and signaling. The network slice may be a network slice provided by the core network (e.g., 5GC). Multiple network slices are distinguished, for example, by the services or use cases provided to UE1 on each network slice. Use cases include, for example, enhanced Mobile Broad Band (eMBB), Ultra-Reliable and Low Latency Communication (URLLC), and massive Machine Type Communication (mMTC). These are called slice types (e.g., Slice / Service Type (SST)). The RAN node 2 may allocate a RAN slice and a radio slice associated with the network slice of the core network selected for UE1 to UE1 to provide end-to-end network slicing to UE1. From the above, the Slicing indication at RACH may be information about the network slice of the core network, or information about the RAN or radio slice, or information about the end-to-end network slice.

[0054] A network slice may be indicated by Network Slice Selection Assistance Information (NSSAI) or Single NSSAI (S-NSSAI). This is notified, for example, from the core network (e.g., 5GC) to the NAS layer 202 of UE1 and from the NAS layer 202 of UE1 to the AS layer 208 (e.g., RRC). The network slice selected by UE1 and the intended network slice may be referred to as selected NSSAI and intended NSSAI, respectively. The selected network slice (selected NSSAI) may be referred to as allowed NSSAI in the sense of the network slice permitted for use by the core network. SST may be included in the S-NSSAI (i.e., the S-NSSAI contains the information of SST).

[0055] More specifically, each of the network slices selected or intended by UE1 may be identified by an identifier known as Single Network Slice Selection Assistance Information (S-NSSAI). The selected or intended network slice may be the S-NSSAI(s) included in the Configured NSSAI or the S-NSSAI(s) included in the Allowed NSSAI. Note that the S-NSSAIs within the Requested NSSAI included in the NAS registration request message need to be part of the Configured NSSAI and / or Allowed NSSAI. Therefore, the intended network slice may be the S-NSSAI(s) included in the Requested NSSAI.

[0056] The Configured NSSAI includes one or more S-NSSAIs, each of which is applicable to one or more Public Land Mobile Networks (PLMNs). The Configured NSSAI is set, for example, by the Serving PLMN and applied to the Serving PLMN. The Allowed NSSAI is provided to UE1 by the Serving PLMN and indicates one or more S-NSSAIs that UE1 can use in the current Registration Area of the Serving PLMN. The Configured NSSAI may be the Default Configured NSSAI. The Default Configured NSSAI is set by the Home PLMN (HPLMN) and applied to any PLMNs for which no specific Configured NSSAI is provided. UE1 may be pre-configured with the Default Configured NSSAI. UE1 may be provisioned or updated with the Default Configured NSSAI determined by the Unified Data Management (UDM) of the HPLMN. The Allowed NSSAI is determined, for example, by the AMF of the Serving PLMN during the registration procedure. The Allowed NSSAI is signaled to UE1 by the network (i.e., AMF) and stored in the respective (non-volatile) memories of the AMF and UE1.

[0057] In some implementations, the AS layer 208 may determine or select a feature combination. In one example, the RRC layer 203 of the UE1 may determine or select a feature combination. Specifically, the RRC layer 203 of the UE1 may determine a feature combination and indicate the determined feature combination to the MAC layer 206 of the UE1. Alternatively, the final determination or selection of the feature combination may be performed by the MAC layer 206 of the UE1. Specifically, the RRC layer 203 of the UE1 may determine one or more features to be included in the feature combination and indicate the determined one or more features to the MAC layer 206 of the UE1. The MAC layer 206 may further determine the required features and determine the feature combination.

[0058] In other implementations, the NAS layer 202 may determine or select a feature combination. The NAS layer 208 may indicate the feature combination to the AS layer 208 (e.g., the RRC layer 203).

[0059] <First Embodiment> The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in FIG. 1. The protocol stack of the control plane of the UE1 may be the same as the example shown in FIG. 2.

[0060] FIG. 3 shows an example of the operation of the UE1 in the random access procedure. Step 301 relates to the RACH resource selection performed by the MAC layer 206 of the UE1. In step 301, the MAC layer 206 of the UE1 selects an SSB having an RSRP exceeding the RSRP threshold associated with the feature or feature combination selected, desired, or intended by the UE1. The SSB selection may also be referred to as beam selection or SSB beam selection. Different beams transmitted by the RAN node 2 are associated with (or mapped to) different SSBs or different SSB indexes. If there is no SSB having an RSRP exceeding the RSRP threshold, the UE1 may select any SSB. The selected, desired, or intended feature or feature combination may be passed from the RRC layer 203 to the MAC layer 206.

[0061] The RSRP threshold may be, for example, rsrp-ThresholdSSB associated with a specific feature or feature combination, or msgA-RSRP-ThresholdSSB associated with a specific feature or feature combination. rsrp-ThresholdSSB is the RSRP threshold for the selection of SSB for 4-step RA. msgA-RSRP-ThresholdSSB is the RSRP threshold for the selection of SSB for 2-step RA.

[0062] The name of the RSRP threshold associated with a specific feature may be defined to indicate the feature. For example, the name may be redCap-rsrp-ThresholdSSB, sdt-rsrp-ThresholdSSB, covEnh-rsrp-ThresholdSSB, and slicing-rsrp-ThresholdSSB (or slice-rsrp-ThresholdSSB). One or more RSRP thresholds may be set for the selection of SSB for each feature.

[0063] Similarly, the name of the RSRP threshold associated with a specific feature combination may be defined to indicate the feature combination. For example, in the case of the combination of RedCap and SDT, the name may be redCap-sdt-rsrp-ThresholdSSB. In the case of the combination of Coverage enhancement and Slicing, the name may be covEnh-Slicing-rsrp-ThresholdSSB. The same may be stipulated for the case of a feature combination including three or more features. When a feature that does not require a special (individual) RSRP threshold is included in a feature combination, the feature may or may not be indicated in the threshold name.

[0064] RAN node 2 may configure UE1 with RSRP thresholds for each feature (e.g., rsrp-ThresholdSSB or msgA-RSRP-ThresholdSSB or both). Specifically, as shown in step 401 of FIG. 4, RAN node 2 may broadcast random access configuration in cell 21. The random access configuration may include, for example, a RACH-ConfigCommon Information element (IE), or may include an IE newly defined within the BWP-UplinkCommon IE (e.g., RACH-ConfigFeatureCombination). The random access configuration may be included in SIB1. For example, the random access configuration includes a plurality of RSRP thresholds each associated with one of a plurality of features or one or more combinations of two or more features each included in a plurality of features. In other words, each of these plurality of RSRP thresholds is associated with any feature or any feature combination. Each of these plurality of RSRP thresholds is used by UE1 for the selection of SSB (or beam). The RRC layer 203 of UE1 provides the plurality of RSRP thresholds included in the random access configuration to the MAC layer 206. The MAC layer 206 selects the RSRP threshold associated with (or corresponding to) the selected feature or feature combination from the plurality of RSRP thresholds.

[0065] Returning to FIG. 3, in step 302, UE1 performs a random access preamble (or RACH preamble) transmission using the random access resource (or RACH resource) corresponding to the selected SSB. Specifically, the MAC layer 206 of UE1 selects one RACH resource for preamble transmission from a set of RACH resources within the RACH resource partition. The RACH resource partition is associated with the selected SSB and is associated with the selected feature or feature combination. The MAC layer 206 of UE1 requests the PHY layer 207 to perform a RACH preamble transmission on the selected RACH resource.

[0066] According to the operation of UE1 described with reference to FIG. 3, UE1 uses the RSRP threshold for each new feature or feature combination introduced in 3GPP Release 17 for SSB (or beam) selection. Therefore, the operation of UE1 described with reference to FIG. 3 enables UE1 to consider a new feature or feature combination or both introduced in 3GPP Release 17 in SSB (or beam) selection. The operation of RAN node 2 described with reference to FIG. 4 sets the RSRP threshold for SSB (or beam) selection for each feature or feature combination. Therefore, the operation of RAN node 2 described with reference to FIG. 4 can assist UE1 in performing SSB (or beam) selection considering features or feature combinations.

[0067] Some variations of the operation shown in FIG. 3 are described below. FIGS. 5 and 6 provide a fallback for the case where there is no SSB (or beam) with an RSRP exceeding the RSRP threshold associated with the selected feature or feature combination. The RSRP measured for the SSB may be the Synchronization Signal RSRP (SS-RSRP).

[0068] Steps 501 and 502 in FIG. 5 correspond to step 301 in FIG. 3. In step 501, UE1 (MAC layer 206) determines whether there is at least one SSB having an RSRP exceeding a first RSRP threshold associated with a selected, desired, or intended feature or feature combination. In other words, UE1 determines whether at least one SSB having an RSRP exceeding the first RSRP threshold associated with the feature or feature combination is available. If there is at least one SSB having an RSRP exceeding the first RSRP threshold (YES in step 501), UE1 selects the SSB having an RSRP exceeding the first RSRP threshold (step 502). The selected, desired, or intended feature or feature combination may be passed from the RRC layer 203 to the MAC layer 206.

[0069] On the contrary, if there is no SSB with an RSRP exceeding the first RSRP threshold (NO in step 502), UE1 attempts to select an SSB using a second RSRP threshold not associated with the selected feature or feature combination (step 503). For example, UE1 may perform random access resource selection in the same way as the random access procedures in 3GPP Release 15 and / or Release 16. In other words, the second threshold may be the same as the RSRP threshold (i.e., rsrp-ThresholdSSB or msgA-RSRP-ThresholdSSB) used in the random access procedures of 3GPP Release 15 and / or Release 16. UE1 may determine whether at least one SSB with an RSRP exceeding the second RSRP threshold is available. If there is an SSB with an RSRP exceeding the second RSRP threshold, UE1 may select the SSB with an RSRP exceeding the second RSRP threshold. If there is no SSB with an RSRP exceeding the second RSRP threshold, UE1 may select any SSB.

[0070] In step 504, UE1 performs RACH preamble transmission using the RACH resource corresponding to the selected SSB. Specifically, the MAC layer 206 of UE1 selects one RACH resource for preamble transmission from the RACH resources within the RACH resource partition. The RACH resource partition is associated with the selected SSB and is the RACH resource partition associated with the selected feature or feature combination. The MAC layer 206 of UE1 requests the PHY layer 207 to perform RACH preamble transmission on the selected RACH resource.

[0071] Figure 6 provides a fallback different from that of Figure 5. Steps 601 and 602 in Figure 6 correspond to step 301 in Figure 3. In step 601, UE1 (MAC layer 206) determines whether there is at least one SSB having an RSRP exceeding a first RSRP threshold associated with a selected, desired, or intended feature combination. In other words, UE1 determines whether at least one SSB having an RSRP exceeding the first RSRP threshold associated with the feature combination is available. If there is at least one SSB having an RSRP exceeding the first RSRP threshold (YES in step 601), UE1 selects an SSB having an RSRP exceeding the first RSRP threshold (step 602). The selected, desired, or intended feature combination may be passed from the RRC layer 203 to the MAC layer 206.

[0072] On the contrary, if there is no SSB having an RSRP exceeding the first RSRP threshold (NO in step 602), UE1 attempts to select an SSB using a third RSRP threshold associated with a feature subset included in the selected feature combination (step 603). The feature subset may be referred to as a subset of features, a feature subcombination, or a subcombination of features. The feature subset includes one or more features. For example, when the selected feature combination is RedCap+Slicing, the feature subset may be RedCap. When the selected feature combination is RedCap+CovEnh+Slicing, the feature subset may be RedCap+CovEnh, RedCap, or CovEnh. UE1 may select a feature subset to be prioritized or a feature subset having a high necessity (or importance). For example, when the feature combination includes RedCap and one or more other features, UE1 may always include RedCap in the feature subset.

[0073] In step 603, UE1 may determine whether at least one SSB with an RSRP exceeding a third RSRP threshold is available. If there is an SSB with an RSRP exceeding the third RSRP threshold, UE1 may select the SSB with an RSRP exceeding the third RSRP threshold. If there is no SSB with an RSRP exceeding the third RSRP threshold, UE1 may select any SSB.

[0074] In step 604, UE1 performs RACH preamble transmission using the RACH resource corresponding to the selected SSB. Specifically, the MAC layer 206 of UE1 selects one RACH resource for preamble transmission from the RACH resources within the RACH resource partition. The RACH resource partition is associated with the selected SSB and is also associated with the selected feature or combination of features. The MAC layer 206 of UE1 requests the PHY layer 207 to perform RACH preamble transmission on the selected RACH resource.

[0075] <Second Embodiment> The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in FIG. 1. The protocol stack of the control plane of UE1 may be the same as the example shown in FIG. 2.

[0076] FIG. 7 shows an example of the operation of UE1 in the random access procedure. In step 701, UE1 performs random access resource selection considering the features or combinations of features selected, desired, or intended by UE1. The random access resource selection includes SSB (or beam) selection. In the random access resource selection, the MAC layer 206 of UE1 first selects an SSB.

[0077] By way of example and not limitation, UE1 may select an SSB in the same manner as step 301 in FIG. 3. The MAC layer 206 of UE1 may select an SSB having an RSRP that exceeds an RSRP threshold associated with a feature or combination of features selected, desired, or intended by UE1. The selected, desired, or intended feature or combination of features may be passed from the RRC layer 203 to the MAC layer 206. Alternatively, the MAC layer 206 of UE1 may perform random access resource selection in the same manner as the random access procedures in 3GPP Release 15 and / or Release 16. In other words, the RSRP threshold for SSB selection may be the same as the RSRP threshold (i.e., rsrp-ThresholdSSB or msgA-RSRP-ThresholdSSB) used in the random access procedures in 3GPP Release 15 and / or Release 16. After selecting an SSB, the MAC layer 206 of UE1 selects a random access resource from a set of random access resources associated with the selected SSB and associated with the selected feature or combination of features. The set of random access resources (or RACH resources) includes RACH preambles, or combinations of RACH opportunities and RACH preambles.

[0078] In step 702, the MAC layer 206 of UE1 performs a random access preamble transmission using the selected random access resource. The MAC layer 206 of UE1 requests the preamble transmission at the selected random access resource from the PHY layer 207.

[0079] In step 703, if the random access response (RAR) reception or contention resolution is not successful, UE1 performs random access resource selection involving the selection of an SSB. UE1 may perform the same random access resource selection as in step 701. That is, UE1 retries the selection of an SSB having an RSRP exceeding the RSRP threshold. The selected SSB may be different from the SSB selected in step 701 for the most recent RACH preamble transmission. For example, as a result of UE1's movement, the SSB currently having the best RSRP may be different from the SSB selected in step 701 in the past. After (re)selecting the SSB, the MAC layer 206 of UE1 selects a random access resource from a set of random access resources associated with the (re)selected SSB and associated with the selected feature or feature combination.

[0080] In step 704, UE1 performs a random access preamble (re)transmission using the (re)selected random access resource. The MAC layer 206 of UE1 requests the PHY layer 207 to transmit a preamble using the (re)selected random access resource.

[0081] The operation of UE1 described with reference to FIG. 7 enables UE1 to perform random access resource selection involving SSB selection prior to retransmitting a random access preamble. The agreement described on page 20 of Non-Patent Document 4 states that "[a]s a general rule, all RACH retransmissions shall be performed over the same RACH resources (and same carrier - NUL / SUL) as the one selected for initial RACH resource." This agreement may have problems from several viewpoints. According to this agreement, for example, even if the best beam (i.e., the beam with the largest SS-RSRP) changes, UE1 cannot change the beam selected in the past. This is because in order to indicate to the network a change in the selected beam (or SSB), UE1 has to change the random access preamble. The operation of UE1 described with reference to FIG. 7 can address this problem.

[0082] <The Third Embodiment> The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in FIG. 1. The protocol stack of the control plane of UE1 may be the same as the example shown in FIG. 2.

[0083] FIG. 8 shows an example of the operation of UE1 in a random access procedure. In step 801, UE1 (MAC layer 206) selects an uplink carrier. In other words, UE1 (MAC layer 206) performs a selection between a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier prior to random access resource selection. The SUL carrier can be set as a complement to the NUL carrier. Generally, in order to complement the coverage of the NUL carrier, the SUL carrier uses a lower uplink frequency than the NUL carrier.

[0084] Specifically, in step 801, the MAC layer 206 of UE1 determines whether both the NUL carrier and the SUL carrier support the features or feature combinations selected, desired, or intended by UE1. In other words, the MAC layer 206 of UE1 determines whether the selected, desired, or intended features or feature combinations are feasible (can be executed) on both the NUL carrier and the SUL carrier. The selected, desired, or intended features or feature combinations may be passed from the RRC layer 203 to the MAC layer 206.

[0085] If the result in step 801 is YES, UE1 (MAC layer 206) selects one of the NUL carrier and the SUL carrier based on the downlink measurement results (step 802). For example, UE1 may operate in the same manner as the selection between the NUL and SUL carriers in 3GPP Release 15 and / or Release 16. If the RSRP of the downlink pathloss reference is lower than the RSRP threshold for uplink carrier selection (e.g., rsrp-ThresholdSSB-SUL), UE1 may select the SUL carrier to perform the random access procedure. Otherwise, UE1 may select the NUL carrier to perform the random access procedure.

[0086] If the result in step 801 is NO, UE1 (MAC layer 206) selects one that supports the selected, desired, or intended features or feature combinations from the NUL carrier and the SUL carrier (step 803).

[0087] In step 804, UE1 performs a random access preamble transmission using the random access resources associated with the selected uplink carrier (NUL or SUL). Specifically, the MAC layer 206 of UE1 selects one RACH resource for use in RACH preamble transmission from a set of random access resources (RACH resources) associated with the selected uplink carrier and associated with the selected feature or combination of features. The set of RACH resources includes RACH preambles, or combinations of RACH occasions and RACH preambles. One RACH occasion is the time and frequency resources for RACH preamble transmission. The MAC layer 206 of UE1 requests the PHY layer 207 to transmit a random access preamble (RACH preamble) using the selected RACH resource.

[0088] According to the operation of UE1 described with reference to FIG. 8, UE1 considers whether the selected feature or combination of features is feasible (supported) in the NUL carrier and / or the SUL carrier in the selection between the NUL carrier and the SUL carrier. Therefore, the operation of UE1 described with reference to FIG. 8 enables UE1 to coordinate the random access resource selection based on Release 17 features or combinations of features with the selection between the NUL carrier and the SUL carrier. Also, this allows the network to not necessarily support the same feature or the same combination of features on both the NUL carrier and the SUL carrier. In other words, the network does not necessarily have to configure the same feature or the same combination of features on both the NUL carrier and the SUL carrier.

[0089] As an example, consider the case where the feature combination includes RedCap and SDT. In this case, UE1 selects an uplink carrier that supports both RedCap and SDT (step 801). If both the NUL carrier and the SUL carrier support both RedCap and SDT, UE1 selects one of the NUL carrier and the SUL carrier based on the downlink measurement results (step 802). On the other hand, if only one of the NUL carrier and the SUL carrier (for example, the NUL carrier) supports both RedCap and SDT, UE1 selects the uplink carrier of that one (for example, the NUL carrier) (step 803). The RedCap UE may not support carrier aggregation (CA), and it is assumed that there is a case where only the NUL carrier needs to be assigned RACH resources for the RedCap UE. The procedure or operation in FIG. 8 is beneficial for this case. Specifically, if the uplink carrier selection is performed based on the downlink measurement results without considering the feature or feature combination, the RedCap UE may select the SUL carrier, and as a result, may not be able to transmit a RACH preamble in the current cell. The procedure or operation in FIG. 8 can solve this problem. Note that regardless of whether the feature combination includes RedCap, the procedure or operation in FIG. 8 can be similarly applied to the case of any combination of two or more features.

[0090] <Fourth Embodiment> The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in FIG. 1. The protocol stack of the control plane of UE1 may be the same as the example shown in FIG. 2.

[0091] Figure 9 shows an example of the operation of UE1. In step 901, UE1 (MAC layer 206) selects one of the NUL carrier and the SUL carrier based on the downlink measurement result (step 802). For example, UE1 may operate in the same manner as the selection between the NUL and SUL carriers in 3GPP Release 15 and / or Release 16. If the RSRP of the downlink pathloss reference is lower than the RSRP threshold for uplink carrier selection (e.g., rsrp-ThresholdSSB-SUL), UE1 may select the SUL carrier to perform the random access procedure. Otherwise, UE1 may select the NUL carrier to perform the random access procedure.

[0092] In step 902, UE1 (MAC layer 206) determines whether the uplink carrier selected in step 801 supports the feature combination selected, desired, or intended by UE1. In other words, the MAC layer 206 of UE1 determines whether the selected, desired, or intended feature combination is executable (can be executed) on the uplink carrier selected in step 801 based on the downlink measurement. The selected, desired, or intended feature combination may be passed from the RRC layer 203 to the MAC layer 206.

[0093] If the answer is YES in step 902, UE1 selects a random access resource from the set of random access resources associated with the selected feature or feature combination (step 903). Specifically, the MAC layer 206 of UE1 selects one RACH resource for RACH preamble transmission from the set of random access resources (RACH resources) associated with the selected uplink carrier and associated with the selected feature or feature combination. The set of RACH resources includes RACH preambles, or combinations of RACH occasions and RACH preambles. One RACH occasion is the time and frequency resources for RACH preamble transmission.

[0094] On the contrary, if the answer is NO in step 902, UE1 selects a random access resource from the set of random access resources associated with the feature subset included in the selected feature combination (step 904). The feature subset includes one or more features. For example, when the selected feature combination is RedCap+Slicing, the feature subset may be RedCap. When the selected feature combination is RedCap+CovEnh+Slicing, the feature subset may be RedCap+CovEnh, RedCap, or CovEnh. The feature subset may be one or more features supported (or executable) by the uplink carrier selected in step 801. UE1 may select the feature subset to be prioritized or the feature subset with high necessity (or importance). For example, when the feature combination includes RedCap and one or more other features, UE1 may always include RedCap in the feature subset.

[0095] In step 905, the MAC layer 206 of UE1 performs a random access preamble transmission using the selected random access resource. Specifically, the MAC layer 206 of UE1 requests the PHY layer 207 to transmit a random access preamble (RACH preamble) using the selected RACH resource.

[0096] When performing the fallback operations in steps 904 and 905, the AS layer 208 of UE1 may notify the NAS layer 202 of a random access failure corresponding to the originally intended feature combination or a fallback to a feature subset. Additionally or alternatively, if the feature subset is also not available in step 904, the AS layer 208 may notify the NAS layer 202 of a random access failure corresponding to the originally intended feature or feature combination. In this case, the AS layer 208 may notify the NAS layer 202 of the failure of the (most) prioritized feature among the feature combinations. Alternatively, the AS layer 208 may notify the NAS layer 202 of a failure regarding a feature for which it is not allowed to determine the necessity or feasibility of executing the function by the feature (e.g., in the MAC layer 206).

[0097] According to the operation of UE1 described with reference to FIG. 9, UE1 first makes a selection between the NUL carrier and the SUL carrier based on downlink measurements. Thereafter, if the feature combination is not supported (or not executable) on the selected uplink carrier, UE1 selects a random access resource associated with the feature subset included in the feature combination. Therefore, the operation of UE1 described with reference to FIG. 9 enables UE1 to coordinate the random access resource selection based on the Release 17 feature combination with the selection between the NUL carrier and the SUL carrier. Also, this allows the network to not necessarily support the same feature or the same feature combination on both the NUL carrier and the SUL carrier. In other words, the network does not necessarily have to configure the same feature or the same feature combination on both the NUL carrier and the SUL carrier.

[0098] <Fifth Embodiment> The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in FIG. 1. The protocol stack of the control plane of UE1 may be the same as the example shown in FIG. 2.

[0099] Figure 10 shows an example of the operation of UE1 in the random access procedure. Steps 1001 to 1003 relate to random access resource selection. In step 1001, UE1 (MAC layer 206) determines whether a first set of random access resources associated with a feature combination selected, desired, or intended by UE1 is set (or available). Note that the RRC layer 203 can configure the MAC layer 206 with a plurality of resource sets (or resource partitions) including the first set. The RRC layer 203 receives the random access configuration from RAN node 2 via broadcast and configures the MAC layer 206 with the plurality of resource sets (or resource partitions) indicated in the random access configuration. Therefore, if it is YES in step 1001, this means that RAN node 2 provides a random access resource set (or resource partition) associated with the feature combination selected, desired, or intended by UE1 in cell 21. In other words, if it is YES in step 1001, this means that the feature combination selected, desired, or intended by UE1 is supported (or available) in cell 21. In contrast, if it is NO in step 1001, this means that RAN node 2 does not provide a random access resource set (or resource partition) associated with the feature combination selected, desired, or intended by UE1 in cell 21. In other words, if it is NO in step 1001, this means that the feature combination selected, desired, or intended by UE1 is not supported (or not available) in cell 21.

[0100] If it is YES in step 1001, UE1 (MAC layer 206) selects a random access resource from the first set (step 1002).

[0101] If the answer is NO in step 1001, UE1 (MAC layer 206) selects a random access resource from a second set of random access resources associated with the feature subset included in the selected feature combination (step 1003). The feature subset includes one or more features. For example, when the selected feature combination is RedCap+Slicing, the feature subset may be RedCap. When the selected feature combination is RedCap+CovEnh+Slicing, the feature subset may be RedCap+CovEnh, RedCap, or CovEnh. The feature subset may be one or more features supported (or executable) in cell 21. UE1 may select a feature subset to be prioritized or a feature subset with high necessity (or importance). For example, when the feature combination includes RedCap and one or more other features, UE1 may always include RedCap in the feature subset.

[0102] In step 1004, the MAC layer 206 of UE1 performs a random access preamble transmission using the selected random access resource. Specifically, the MAC layer 206 of UE1 requests the PHY layer 207 to transmit a random access preamble (RACH preamble) on the selected RACH resource.

[0103] When performing the fallback operations in steps 1003 and 1004, the AS layer 208 of UE1 may notify the NAS layer 202 of a random access failure corresponding to the originally intended feature combination or a fallback to a feature subset. Additionally or alternatively, if the feature subset is also not available in step 1003, the AS layer 208 may notify the NAS layer 202 of a random access failure corresponding to the originally intended feature or feature combination. In this case, the AS layer 208 may notify the NAS layer 202 of the failure of the (most) prioritized feature among the feature combinations. Alternatively, the AS layer 208 may notify the NAS layer 202 of a failure regarding a feature for which it is not allowed to determine the necessity or feasibility of executing the function of the feature (e.g., MAC layer 206) in the AS layer 208.

[0104] According to the operation of UE1 described with reference to FIG. 10, if cell 21 does not provide a RACH resource set associated with a feature combination selected, desired, or intended by UE1, UE1 selects a RACH resource for random access to cell 21 from among alternative RACH resource sets associated with a feature subset included in the feature combination and provided by cell 21. This operation of UE1 allows cell 21 or RAN node 2 to provide only a plurality of RACH resource sets for some of all possible feature combinations. Therefore, cell 21 does not necessarily have to provide all RACH resource sets for all possible feature combinations. This can contribute to reducing the fragmentation of random access resources.

[0105] <Sixth Embodiment> The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in FIG. 1. The protocol stack of the control plane of UE1 may be the same as the example shown in FIG. 2.

[0106] FIG. 11 shows an example of the operation of UE1 in the random access procedure. Steps 1101 to 1103 relate to random access resource selection. In step 1101, UE1 (MAC layer 206) determines whether a first set of random access resources associated with a feature or combination of features selected, desired, or intended by UE1 is set (or available). Note that the RRC layer 203 can configure the MAC layer 206 with a plurality of resource sets (or resource partitions) including the first set. The RRC layer 203 receives the random access configuration via broadcast from RAN node 2 and configures the MAC layer 206 with the plurality of resource sets (or resource partitions) indicated in the random access configuration. Therefore, if it is YES in step 1101, this means that RAN node 2 provides a random access resource set (or resource partition) associated with the feature or combination of features selected, desired, or intended by UE1 in cell 21. In other words, if it is YES in step 1101, this means that the feature or combination of features selected, desired, or intended by UE1 is supported (or available) in cell 21. In contrast, if it is NO in step 1101, this means that RAN node 2 does not provide a random access resource set (or resource partition) associated with the feature or combination of features selected, desired, or intended by UE1 in cell 21. In other words, if it is NO in step 1101, this means that the feature or combination of features selected, desired, or intended by UE1 is not supported (or not available) in cell 21.

[0107] If the result in step 1101 is YES, UE1 (MAC layer 206) selects a random access resource from the first set (step 1102).

[0108] If the result in step 1101 is NO, UE1 (MAC layer 206) selects a random access resource from a second set of random access resources not associated with the selected feature or feature combination (step 1103). For example, UE1 may select a random access resource in the same way as the random access procedure in 3GPP Release 15 and / or Release 16.

[0109] In step 1104, the MAC layer 206 of UE1 performs a random access preamble transmission using the selected random access resource. Specifically, the MAC layer 206 of UE1 requests the PHY layer 207 to transmit a random access preamble (RACH preamble) using the selected RACH resource.

[0110] When performing the fallback operations in steps 1103 and 1104, the AS layer 208 of UE1 may notify the NAS layer 202 of a random access failure corresponding to the originally intended feature combination or a fallback to a random access that does not consider the feature combination.

[0111] According to the operation of UE1 described with reference to FIG. 11, if cell 21 does not provide a RACH resource set associated with the feature combination selected, desired, or intended by UE1, UE1 selects a RACH resource for random access to cell 21 from among alternative RACH resource sets not associated with the feature combination. This operation of UE1 allows cell 21 or RAN node 2 to provide only a plurality of RACH resource sets for some of all possible features and feature combinations. Therefore, cell 21 does not necessarily have to provide all RACH resource sets for all possible features and feature combinations. This can contribute to reducing the fragmentation of random access resources.

[0112] <Seventh Embodiment> A configuration example of the wireless communication system according to this embodiment may be the same as the example shown in FIG. 1. The protocol stack of the control plane of UE1 may be the same as the example shown in FIG. 2.

[0113] This embodiment relates to handling of features and feature combinations selected, desired, or intended by UE1. Features can be classified into at least two types. In the first type, the MAC layer 206 of UE1 determines the necessity (or possibility) of executing the feature based on information or conditions predetermined by itself. Additionally or alternatively, the MAC layer 206 may make the above determination based on information received or specified from an upper layer (e.g., RRC layer 203) of UE1. In this type, when the MAC layer 206 of UE1 determines that at least one feature of the selected, desired, or intended feature combination does not need to be executed (or cannot be executed), the MAC layer 206 may change the content (i.e., the included features) of the feature combination so as to select a RACH resource for the remaining features or feature combination excluding the said feature. In other words, the MAC layer 206 may select a feature subset excluding the feature that does not need to be executed (or cannot be executed). In this case, the MAC layer 206 may notify the RRC layer 203 of the determination result (for example, information on the feature combination to be executed, information on the excluded feature).

[0114] The second type is such that the MAC layer 206 of the UE1 does not or must not determine the necessity of executing that feature (or whether the execution of that feature is possible). In this type, the RRC layer 203 of the UE1 determines the necessity of executing that feature (or whether the execution of that feature is possible), and notifies the necessary information to the MAC layer 206. The determination by the RRC layer 203 may be made based on one or both of the UE capability of the UE1 and the predetermined information held by the RRC layer 203. Further or alternatively, the RRC layer 203 may make the above determination based on the information received or specified from a higher layer (e.g., NAS layer 202) of the UE1. The MAC layer 206 selects a RACH resource corresponding to that feature or a feature combination including that feature. If the MAC layer 206 determines that there is no RACH resource corresponding to that feature, it may report a failure indication of RACH resource selection to the RRC layer 203. On the other hand, if the MAC layer 206 determines that there is no RACH resource corresponding to a feature combination including that feature, the MAC layer 206 excludes any one or more features corresponding to the first type from the feature combination, and may select a RACH resource corresponding to a feature subset including the features of the second type and the remaining one or more features corresponding to the first type. Alternatively, the MAC layer 206 may select a RACH resource corresponding only to the features of the second type. In other words, when it is necessary to select a feature subset from the feature combination, the MAC layer 206 may always include one or more features of the second type (e.g., RedCap) included in the feature combination in the feature subset. Then, the MAC layer 206 may adjust the number of features in the feature subset depending on whether to include the features of the first type included in the feature combination in the feature subset.

[0115] The feature combination selected, desired, or intended by UE1 may include only one of the above two types, or may include both types. When the feature combination includes both types, MAC layer 206 may preferentially consider the features of the second type. For example, MAC layer 206 may prioritize executing the features of the second type. MAC layer 206 may preferentially select RACH resources corresponding to the features of the second type.

[0116] <Eighth Embodiment> The configuration example of the wireless communication system according to this embodiment may be the same as the example shown in FIG. 1. The protocol stack of the control plane of UE1 may be the same as the example shown in FIG. 2.

[0117] RAN node 2 broadcasts a random access configuration (e.g., RACH-ConfigCommon) in cell 21. The random access configuration provides, together with other settings, partitions of random access resources to UE1. In other words, the random access configuration indicates a random access resource configuration indicating partitions of random access resources. According to the received random access resource configuration, UE1 selects a random access resource partition corresponding to the selected, desired, or intended feature or feature combination, and selects a random access resource from the partition.

[0118] The RAN node 2 can generate random access resource settings as follows. The random access resource partitioning for only one feature is different from the random access resource partitioning for a combination of multiple features including the said feature in terms of the granularity (resolution) of distinguishing or identifying the said feature. This contributes to suppressing the increase in the number of random access resource partitions for the feature combination. In other words, this can contribute to reducing the fragmentation of random access resources.

[0119] In one example, the random access resource partitioning for only the feature Slicing may provide three or more resource partitions for distinguishing three or more network slice groups. Thereby, the Slicing indication by the random access resource selection of the UE1 can provide the RAN node 2 with the distinction between two or less network slice groups.

[0120] In contrast, the random access resource partitioning for a feature combination including the feature Slicing (e.g., SDT + Slicing, RedCap + Slicing) may provide the distinction between two or less network slice groups. Therefore, regarding the feature Slicing, the said resource partitioning may provide two or less resource partitions for enabling the distinction between two or less network slice groups.

[0121] Alternatively, the random access resource partitioning for a feature combination including the feature Slicing may provide only a two-dimensional (binary) distinction between prioritized and non-prioritized network slices. Thus, with respect to the feature Slicing, the resource partitioning may provide only one resource partition for distinguishing prioritized network slices.

[0122] In other examples, the random access resource partitioning for only the feature CovEnh may provide three or more resource partitions for enabling the distinction of three or more CE levels.

[0123] In contrast, the random access resource partitioning for a feature combination including the feature CovEnh (e.g., SDT+CovEnh, RedCap+CovEnh) may provide the distinction of two or more CE level groups. Thus, with respect to the feature CovEnh, the resource partitioning may provide two or more resource partitions for enabling the distinction of two or more CE level groups.

[0124] Alternatively, the random access resource partitioning for a feature combination including the feature CovEnh may provide only a two-dimensional (binary) distinction as to whether Msg3 PUSCH repetition is required. Thus, with respect to the feature CovEnh, the resource partitioning may provide only one resource partition to be used when Msg3 PUSCH repetition is required.

[0125] Next, a configuration example of the UE1 and the RAN node 2 according to the above-described plurality of embodiments will be described below. FIG. 12 is a block diagram showing a configuration example of the UE1. A Radio Frequency (RF) transceiver 1201 performs analog RF signal processing to communicate with a RAN node. The RF transceiver 1201 may include a plurality of transceivers. The analog RF signal processing performed by the RF transceiver 1201 includes frequency up-conversion, frequency down-conversion, and amplification. The RF transceiver 1201 is coupled to an antenna array 1202 and a baseband processor 1203. The RF transceiver 1201 receives modulation symbol data (or OFDM symbol data) from the baseband processor 1203, generates a transmission RF signal, and supplies the transmission RF signal to the antenna array 1202. Also, the RF transceiver 1201 generates a baseband reception signal based on the reception RF signal received by the antenna array 1202 and supplies this to the baseband processor 1203. The RF transceiver 1201 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, a plurality of phase shifters and a plurality of power amplifiers.

[0126] The baseband processor 1203 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) generation / decomposition of a transmission format (transmission frame), (d) channel coding / decoding, (e) modulation (symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) by Inverse Fast Fourier Transform (IFFT), etc. On the other hand, the control plane processing includes communication management of layer 1 (e.g., transmission power control), layer 2 (e.g., radio resource management, and hybrid automatic repeat request (HARQ) processing), and layer 3 (e.g., signaling related to attachment, mobility, and call management).

[0127] For example, the digital baseband signal processing by the baseband processor 1203 may include signal processing of the Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and Physical (PHY) layer. Also, the control plane processing by the baseband processor 1203 may include processing of the Non-Access Stratum (NAS) protocol, Radio Resource Control (RRC) protocol, MAC Control Elements (CEs), and Downlink Control Information (DCIs).

[0128] The baseband processor 1203 may perform Multiple Input Multiple Output (MIMO) encoding and precoding for beamforming.

[0129] The baseband processor 1203 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., Central Processing Unit (CPU) or Micro Processing Unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 1204 described later.

[0130] The application processor 1204 is also referred to as a CPU, MPU, microprocessor, or processor core. The application processor 1204 may include a plurality of processors (a plurality of processor cores). The application processor 1204 realizes various functions of the UE1 by executing a system software program (Operating System (OS)) read from the memory 1206 or a memory not shown and various application programs (for example, a call application, a WEB browser, a mailer, a camera operation application, a music playback application).

[0131] In some implementations, as shown by the dashed line (1205) in FIG. 12, the baseband processor 1203 and the application processor 1204 may be integrated on one chip. In other words, the baseband processor 1203 and the application processor 1204 may be implemented as one System on Chip (SoC) device 1205. The SoC device may also be referred to as a system Large Scale Integration (LSI) or a chipset.

[0132] The memory 1206 is a volatile memory, a non-volatile memory, or a combination thereof. The memory 1206 may physically include a plurality of independent memory devices. The volatile memory is, for example, Static Random Access Memory (SRAM), Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is a mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. For example, the memory 1206 may include an external memory device accessible from the baseband processor 1203, the application processor 1204, and the SoC 1205. The memory 1206 may include an embedded memory device integrated within the baseband processor 1203, within the application processor 1204, or within the SoC 1205. Further, the memory 1206 may include a memory within a Universal Integrated Circuit Card (UICC).

[0133] The memory 1206 may store one or more software modules (computer programs) 1207 including instruction groups and data for performing the processing by the UE1 described in the above-described multiple embodiments. In some implementations, the baseband processor 1203 or the application processor 1204 may be configured to perform the processing of the UE1 described with reference to the drawings in the above-described embodiments by reading and executing the software module 1207 from the memory 1206.

[0134] Note that the control plane processing and operations performed by the UE1 described in the above-described embodiments can be realized by other elements excluding the RF transceiver 1201 and the antenna array 1202, that is, at least one of the baseband processor 1203 and the application processor 1204 and the memory 1206 storing the software module 1207.

[0135] FIG. 13 is a block diagram showing a configuration example of the RAN node 2 according to the above-described embodiment. Referring to FIG. 13, the RAN node 2 includes a Radio Frequency transceiver 1301, a network interface 1303, a processor 1304, and a memory 1305. The RF transceiver 1301 performs analog RF signal processing to communicate with UEs including the UE1. The RF transceiver 1301 may include a plurality of transceivers. The RF transceiver 1301 is coupled to the antenna array 1302 and the processor 1304. The RF transceiver 1301 receives modulation symbol data from the processor 1304, generates a transmission RF signal, and supplies the transmission RF signal to the antenna array 1302. Also, the RF transceiver 1301 generates a baseband reception signal based on the reception RF signal received by the antenna array 1302 and supplies this to the processor 1304. The RF transceiver 1301 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, a plurality of phase shifters and a plurality of power amplifiers.

[0136] The network interface 1303 is used to communicate with network nodes (e.g., SN2, as well as control nodes and transfer nodes of the core network). The network interface 1303 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0137] Processor 1304 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Processor 1304 may include a plurality of processors. For example, Processor 1304 may include a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., Central Processing Unit (CPU) or Micro Processing Unit (MPU)) that performs control plane processing. Processor 1304 may include a digital beamformer module for beamforming. The digital beamformer module may include a Multiple Input Multiple Output (MIMO) encoder and a precoder.

[0138] Memory 1305 is composed of a combination of volatile memory and non-volatile memory. The volatile memory is, for example, Static Random Access Memory (SRAM) or Dynamic RAM (DRAM) or a combination thereof. The non-volatile memory is a mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. Memory 1305 may include storage located away from Processor 1304. In this case, Processor 1304 may access Memory 1305 via Network Interface 1303 or an I / O interface (not shown).

[0139] Memory 1305 may store one or more software modules (computer programs) 1306 containing instruction groups and data for the processing by the RAN node 2 described in the above-described multiple embodiments. In some implementations, the processor 1304 may be configured to perform the processing of the RAN node 2 described in the above-described embodiments by reading out and executing the software module 1306 from the memory 1305.

[0140] Note that when the RAN node 2 is a CU (e.g., gNB-CU) or a CU-CP (e.g., gNB-CU-CP), the RAN node 2 may not include the RF transceiver 1301 (and the antenna array 1302).

[0141] As described with reference to FIGS. 12 and 13, each of the processors included in the UE 1 and the RAN node 2 according to the above-described embodiments can execute one or more programs including instruction groups for causing a computer to perform the algorithms described with reference to the drawings. The program includes instruction groups (or software code) for causing a computer to perform one or more functions described in the embodiments when loaded into the computer. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, the computer-readable medium or the tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD), or other memory technologies, CD-ROM, digital versatile disk (DVD), Blu-ray (registered trademark) disk, or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage devices. The program may be transmitted on a transitory computer-readable medium or a communication medium. By way of example and not limitation, the transitory computer-readable medium or the communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0142] <Other Embodiments> In the above embodiments, the "feature" may be a feature newly introduced in future 3GPP Release 18 or later. Similarly, in the above embodiments, the "feature combination" may include features newly introduced in future 3GPP Release 18 or later. For example, in addition to Mobile Originated (MO) SDT introduced in Release 17, Mobile Terminated (MT) SDT is planned to be additionally introduced in 3GPP Release 18. In one implementation, the feature MT-SDT may be distinguished from the feature MO-SDT, and an individual RACH resource set (or partition, or pool) may be configured for the feature MT-SDT. In this case, the feature combination may include MT-SDT. The RAN node 2 may inform the UE1, via broadcast (e.g., SIB) or individual RRC signaling, whether MO-SDT and MT-SDT are distinguished in the RACH resource partition. Specifically, the random access configuration (e.g., RACH-Config) sent from the RAN node 2 to the UE1 may include a 1-bit flag (e.g., "mt-SDT") as an optional element. If the random access configuration includes the flag, the UE1 may use the RACH resource set for the feature (MO-)SDT for MT-SDT. On the contrary, if the random access configuration does not include the flag, the UE1 may check whether an individual RACH resource set (or partition, or pool) is configured for MT-SDT, and if it is configured, use the individual RACH resource set for the MT-SDT. If the random access configuration does not include the flag and no individual RACH resource set is configured for MT-SDT, the UE1 may understand that MT-SDT is not supported. In this case, if the UE1 triggers MT-SDT, the UE1 may use the RACH resource set for the feature (MO-)SDT for MT-SDT, or use a RACH resource set similar to Release 15 and / or Release 16 for MT-SDT.

[0143] In the above embodiments, if the configuration, information, or field related to the features (e.g., Release 17 features) not supported by UE1 is included in the configuration (e.g., random access configuration) received via RRC signaling (e.g., SIB), UE1 may operate so as not to ignore the value (or code point) of the configuration, information, or field.

[0144] For example, UE1 may recognize the size of the RACH resource set (or partition) of the feature or feature combination it desires based on the value of the first ra-PreambleStartIndex field related to the feature or feature combination it desires and the value of the second ra-PreambleStartIndex field of another feature or feature combination immediately following it. In this case, regardless of whether UE1 supports the feature or feature combination associated with the second ra-PreambleStartIndex field, the value of the second ra-PreambleStartIndex field shall not be ignored.

[0145] In some of the above embodiments, for a specific feature or a feature combination including it, UE1 may perform operations (or processes) different from those of the above embodiments. For example, regarding uplink carrier selection, for a specific feature (e.g., RedCap) or a feature combination including it, the uplink carrier to be selected (e.g., NUL carrier) may be predetermined (or specified in the specification). This is beneficial for fully utilizing the function of the feature or considering the limitations in the function of the feature.

[0146] In some of the above embodiments, for a specific feature or a combination of features including the same, UE1 may perform operations (or processes) different from those of the above embodiments. For example, for a specific feature (e.g., Coverage enhancement), after uplink carrier selection, UE1 may determine the necessity of the feature (or whether to execute the feature). This is beneficial when the function of the feature depends on the result of uplink carrier selection.

[0147] Furthermore, the above-described embodiments are merely examples regarding the application of the technical idea obtained by the present inventor. That is, the technical idea is not limited to only the above-described embodiments, and it goes without saying that various modifications are possible.

[0148] For example, some or all of the above embodiments may be described as follows in the appended claims, but are not limited thereto.

[0149] (Appended Claim 1) At least one memory, At least one processor coupled to the at least one memory, The at least one processor is configured to select a beam having a Reference Signal Received Power (RSRP) exceeding a first RSRP threshold associated with a selected, desired, or intended feature or combination of features from a plurality of beamformed beams, perform a random access preamble transmission using a first random access resource corresponding to the selected beam, wherein the feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing, the combination of features includes at least two of RedCap, SDT, CovEnh, and Slicing, Wireless terminal. (Appendix 2) If there is no beam having an RSRP exceeding the first RSRP threshold, the at least one processor is configured to perform beam selection using a second RSRP threshold not associated with the feature or the feature combination. The wireless terminal according to Appendix 1. (Appendix 3) If there is no beam having an RSRP exceeding the first RSRP threshold, the at least one processor is configured to perform beam selection using a third threshold associated with a feature subset included in the feature combination. The wireless terminal according to Appendix 1 or 2. (Appendix 4) If random access response reception or contention resolution fails after transmission of the first random access resource, the at least one processor is configured to perform random access resource selection before retransmitting the random access preamble. The random access resource selection includes retrying to select a beam having an RSRP exceeding the first RSRP threshold. The wireless terminal according to any one of Appendices 1 to 3. (Appendix 5) The at least one processor receives a plurality of RSRP thresholds, each associated with one of a plurality of features or one or more combinations of two or more features included in the plurality of features, from a radio access network node. Selects the first RSRP threshold from the plurality of RSRP thresholds. Is configured as The plurality of features includes at least two of RedCap, SDT, CovEnh, and Slicing. The wireless terminal according to any one of Appendices 1 to 4. (Appendix 6) The plurality of beams are associated with different Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) blocks (SSBs), The selection of the beam by the at least one processor is performed by selecting an SSB, The wireless terminal according to any one of Appendices 1 to 5. (Appendix 7) The at least one processor, If both a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier support the feature or the feature combination, select one of the NUL carrier and the SUL carrier based on downlink measurement results; otherwise, select one of the NUL carrier and the SUL carrier that supports the feature or the feature combination from the NUL carrier and the SUL carrier, Select the first random access resource from a set of random access resources associated with the selected uplink carrier, is configured to, The wireless terminal according to any one of Appendices 1 to 6. (Appendix 8) The at least one processor, Select one of the uplink carriers of a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier based on downlink measurement results, If the selected uplink carrier does not support the feature combination, select the first random access resource from a set of random access resources associated with a feature subset included in the feature combination, is configured to, The wireless terminal according to any one of Appendices 1 to 6. (Appendix 9) The at least one processor, If a first set of random access resources associated with the feature combination is set, select the first random access resource from the first set; If the first set is not set, select the first random access resource from a second set of random access resources associated with a feature subset included in the feature combination; is configured to The wireless terminal according to any one of Appendices 1 to 8. (Appendix 10) The at least one processor If a first set of random access resources associated with the feature or the feature combination is set, select the first random access resource from the first set; If the first set is not set, select the first random access resource from a second set of random access resources not associated with the feature or the feature combination; is configured to The wireless terminal according to any one of Appendices 1 to 8. (Appendix 11) Selecting a beam having a Reference Signal Received Power (RSRP) exceeding a first RSRP threshold associated with a selected, desired, or intended feature or feature combination from a plurality of beamformed beams, and Performing random access preamble transmission using a first random access resource corresponding to the selected beam; comprising The feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing; The feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing; A method performed by a wireless terminal. (Appendix 12) A program for causing a computer to perform a method for a wireless terminal, wherein the method comprises: selecting, from a plurality of beamformed beams, a beam having a Reference Signal Received Power (RSRP) exceeding a first RSRP threshold associated with a selected, desired, or intended feature or feature combination; and performing a random access preamble transmission using a first random access resource corresponding to the selected beam, comprising: wherein the feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing; wherein the feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing; a program. (Appendix 13) at least one memory; at least one processor coupled to the at least one memory; comprising: wherein the at least one processor is configured to broadcast, in a cell, a first Reference Signal Received Power (RSRP) threshold associated with a feature or feature combination; wherein the first RSRP threshold is used by a wireless terminal to select, from a plurality of beamformed beams, a beam having an RSRP exceeding the first RSRP threshold, and to perform a random access preamble transmission using a first random access resource corresponding to the selected beam; ​The feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing, The feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing, A radio access network node. (Appendix 14) The at least one processor is configured to broadcast a plurality of RSRP thresholds including the first RSRP threshold, The plurality of RSRP thresholds are each associated with one of a plurality of features or one or more combinations of two or more features included in the plurality of features, The plurality of features includes at least two of RedCap, SDT, CovEnh, and Slicing, The radio access network node according to Appendix 13. (Appendix 15) Comprising broadcasting, in a cell, a first Reference Signal Received Power (RSRP) threshold associated with a feature or feature combination, The first RSRP threshold is used by a wireless terminal to select a beam having an RSRP exceeding the first RSRP threshold from a plurality of beamformed beams and perform a random access preamble transmission using a first random access resource corresponding to the selected beam, The feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing, The feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing, A method performed by a radio access network node. (Appendix 16) A program for causing a computer to perform a method for a radio access network node, The method comprises broadcasting, in a cell, a first Reference Signal Received Power (RSRP) threshold associated with a feature or combination of features, The first RSRP threshold is used by a wireless terminal to select, from a plurality of beamformed beams, a beam having an RSRP exceeding the first RSRP threshold and perform a random access preamble transmission using a first random access resource corresponding to the selected beam, The feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing, The combination of features includes at least two of RedCap, SDT, CovEnh, and Slicing, Program. (Appendix 17) At least one memory, At least one processor coupled to the at least one memory, The at least one processor, If both a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier support a selected, desired, or intended feature or combination of features, select one of the NUL carrier and the SUL carrier based on downlink measurement results; otherwise, select the one of the NUL carrier and the SUL carrier that supports the feature or combination of features, Perform a random access preamble transmission using a random access resource associated with the selected uplink carrier, Is configured to, Wireless terminal. (Appendix 18) The feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing, The feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing, The wireless terminal according to Supplementary Note 17. (Supplementary Note 19) If both a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier support a selected, desired, or intended feature or feature combination, select one of the NUL carrier and the SUL carrier based on downlink measurement results; otherwise, select the one of the NUL carrier and the SUL carrier that supports the feature or the feature combination, and Perform random access preamble transmission using the random access resources associated with the selected uplink carrier, Comprising A method performed by a wireless terminal. (Supplementary Note 20) A program for causing a computer to perform a method for a wireless terminal, The method is If both a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier support a selected, desired, or intended feature or feature combination, select one of the NUL carrier and the SUL carrier based on downlink measurement results; otherwise, select the one of the NUL carrier and the SUL carrier that supports the feature or the feature combination, and Perform random access preamble transmission using the random access resources associated with the selected uplink carrier, Comprising A program. (Supplementary Note 21) At least one memory, and at least one processor coupled to the at least one memory, wherein the at least one processor selects one of a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier as an uplink carrier based on downlink measurement results, and if the selected uplink carrier does not support a selected, desired, or intended feature combination, performs a random access preamble transmission using random access resources associated with a feature subset included in the feature combination. is configured to a wireless terminal. (Appendix 22) wherein the at least one processor is configured to perform a random access preamble transmission using random access resources associated with the feature combination if the selected uplink carrier supports the feature combination. The wireless terminal according to Appendix 21. (Appendix 23) The feature combination includes at least two of Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing. The wireless terminal according to Appendix 21 or 22. (Appendix 24) selecting one of a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier as an uplink carrier based on downlink measurement results, and if the selected uplink carrier does not support a selected, desired, or intended feature combination, performing a random access preamble transmission using random access resources associated with a feature subset included in the feature combination. comprising A method performed by a wireless terminal. (Appendix 25) A program for causing a computer to perform a method for a wireless terminal, wherein the method comprises: selecting one of a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier as an uplink carrier based on downlink measurement results, and performing a random access preamble transmission using a random access resource associated with a feature subset included in the feature combination if the selected uplink carrier does not support the selected, desired, or intended feature combination. A program. (Appendix 26) At least one memory, and At least one processor coupled to the at least one memory, wherein the at least one processor is configured to: perform a random access preamble transmission using a random access resource selected from a first set of random access resources associated with a selected, desired, or intended feature combination if the first set is configured; or perform a random access preamble transmission using a random access resource selected from a second set of random access resources associated with a feature subset included in the feature combination if the first set is not configured. A wireless terminal. (Appendix 27) The feature combination includes at least two of Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing. The wireless terminal according to Appendix 26. (Appendix 28) If a first set of random access resources associated with a selected, desired, or intended feature combination is set, performing a random access preamble transmission using a random access resource selected from the first set, and if the first set is not set, performing a random access preamble transmission using a random access resource selected from a second set of random access resources associated with a feature subset included in the feature combination, comprising A method performed by a wireless terminal. (Appendix 29) A program for causing a computer to perform a method for a wireless terminal, the method comprising if a first set of random access resources associated with a selected, desired, or intended feature combination is set, performing a random access preamble transmission using a random access resource selected from the first set, and if the first set is not set, performing a random access preamble transmission using a random access resource selected from a second set of random access resources associated with a feature subset included in the feature combination, comprising A program. (Appendix 30) (Appendix 30) at least one memory, and at least one processor coupled to the at least one memory, wherein the at least one processor performs a random access preamble transmission using a random access resource selected from a first set of random access resources associated with a selected, desired, or intended feature or feature combination if the first set is set, ​If the first set is not set, perform random access preamble transmission using a random access resource selected from a second set of random access resources not associated with the feature or the feature combination. configured as a wireless terminal. (Appendix 31) The feature is Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing, and the feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing. The wireless terminal according to Appendix 30. (Appendix 32) If a first set of random access resources associated with a selected, desired, or intended feature or feature combination is set, perform random access preamble transmission using the random access resource selected from the first set, and if the first set is not set, perform random access preamble transmission using a random access resource selected from a second set of random access resources not associated with the feature or the feature combination. comprising A method performed by a wireless terminal. (Appendix 33) A program for causing a computer to perform a method for a wireless terminal, the method comprising: If a first set of random access resources associated with a selected, desired, or intended feature or feature combination is set, perform random access preamble transmission using the random access resource selected from the first set, and if the first set is not set, perform random access preamble transmission using a random access resource selected from a second set of random access resources not associated with the feature or the feature combination. If the first set is not set, perform random access preamble transmission using a random access resource selected from a second set of random access resources not associated with the feature or the feature combination. Comprising Program.

[0150] This application claims priority based on Japanese Patent Application No. 2021-171920 filed on October 20, 2021, and incorporates the entire disclosure thereof herein.

Explanation of Signs

[0151] 1 UE 2 RAN Node 21 Cell 1203 Baseband Processor 1204 Application Processor 1206 Memory 1207 Modules 1304 Processor 1305 Memory 1306 Modules

Claims

1. means for selecting an SSB having an RSRP exceeding a first Reference Signal Received Power (RSRP) threshold associated with a feature or combination of features and configured for Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) block (SSB) selection; means for transmitting a random access preamble using a first random access opportunity corresponding to the selected SSB; comprising; wherein the feature is any one of Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing; wherein the combination of features includes at least two of RedCap, SDT, CovEnh, and Slicing; a wireless terminal.

2. further comprising means for performing SSB selection using a second RSRP threshold not associated with the feature or the combination of features if there is no SSB having an RSRP exceeding the first RSRP threshold; The wireless terminal according to claim 1.

3. further comprising means for performing SSB selection using a third threshold associated with a subset of features included in the combination of features if there is no SSB having an RSRP exceeding the first RSRP threshold; The wireless terminal according to claim 1.

4. further comprising means for performing random access resource selection before retransmitting a random access preamble if random access response reception or contention resolution fails after transmission at the first random access opportunity, wherein the random access resource selection includes retrying to select an SSB having an RSRP exceeding the first RSRP threshold; The wireless terminal according to any one of claims 1 to 3.

5. means for receiving a plurality of RSRP thresholds, each associated with one of a plurality of features or one or more combinations of two or more features included in the plurality of features, from a radio access network node; means for selecting the first RSRP threshold from the plurality of RSRP thresholds; further comprising; wherein the plurality of features includes at least two of RedCap, SDT, CovEnh, and Slicing; The wireless terminal according to any one of claims 1 to 3.

6. If both a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier support the feature or the combination of features, means for selecting one of the NUL carrier and the SUL carrier based on a downlink measurement result, and otherwise means for selecting one of the NUL carrier and the SUL carrier that supports the feature or the combination of features from the NUL carrier and the SUL carrier; Means for selecting the first random access opportunity from a set of random access resources associated with the selected uplink carrier; Further comprising The wireless terminal according to any one of claims 1 to 3.

7. Means for selecting one of a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier as an uplink carrier based on a downlink measurement result; If the selected uplink carrier does not support the combination of features, means for selecting the first random access opportunity from a set of random access resources associated with a feature subset included in the combination of features; Further comprising The wireless terminal according to any one of claims 1 to 3.

8. If a first set of random access resources associated with the combination of features is set, means for selecting the first random access opportunity from the first set; If the first set is not set, means for selecting the first random access opportunity from a second set of random access resources associated with a feature subset included in the combination of features; Further comprising The wireless terminal according to any one of claims 1 to 3.

9. If a first set of random access resources associated with the feature or the combination of features is set, means for selecting the first random access opportunity from the first set; If the first set is not set, means for selecting the first random access opportunity from a second set of random access resources not associated with the feature or the combination of features; Further comprising The wireless terminal according to any one of claims 1 to 3.

10. Selecting an SSB having an RSRP exceeding a first Reference Signal Received Power (RSRP) threshold associated with a feature or feature combination and configured for Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) block (SSB) selection, and Performing a random access preamble transmission using a first random access opportunity corresponding to the selected SSB, Comprising: The feature is any one of Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing, The feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing, A method performed by a wireless terminal.

11. Further comprising, if there is no SSB having an RSRP exceeding the first RSRP threshold, performing SSB selection using a second RSRP threshold not associated with the feature or the feature combination, The method according to claim 10.

12. Further comprising, if there is no SSB having an RSRP exceeding the first RSRP threshold, performing SSB selection using a third threshold associated with a feature subset included in the feature combination, The method according to claim 10.

13. Further comprising, if random access response reception or contention resolution fails after transmission at the first random access opportunity, performing random access resource selection before retransmitting the random access preamble, The random access resource selection includes retrying to select an SSB having an RSRP exceeding the first RSRP threshold, The method according to any one of claims 10 to 12.

14. Receiving a plurality of RSRP thresholds, each associated with one of a plurality of features or one or more combinations of two or more features included in the plurality of features, from a radio access network node, and Selecting the first RSRP threshold from the plurality of RSRP thresholds, Further comprising, The plurality of features includes at least two of RedCap, SDT, CovEnh, and Slicing. The method according to any one of claims 10 to 12.

15. If both a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier support the feature or the feature combination, select one of the NUL carrier and the SUL carrier based on downlink measurement results; otherwise, select one of the NUL carrier and the SUL carrier that supports the feature or the feature combination, and select the first random access opportunity from a set of random access resources associated with the selected uplink carrier. further comprising The method according to any one of claims 10 to 12.

16. Select one of the uplink carriers of a Normal Uplink (NUL) carrier and a Supplementary Uplink (SUL) carrier based on downlink measurement results, and if the selected uplink carrier does not support the feature combination, select the first random access opportunity from a set of random access resources associated with a feature subset included in the feature combination. further comprising The method according to any one of claims 10 to 12.

17. If a first set of random access resources associated with the feature combination is set, select the first random access opportunity from the first set, and if the first set is not set, select the first random access opportunity from a second set of random access resources associated with a feature subset included in the feature combination. further comprising The method according to any one of claims 10 to 12.

18. If a first set of random access resources associated with the feature or the feature combination is set, select the first random access opportunity from the first set, and If the first set is not set, selecting the first random access opportunity from a second set of random access resources not associated with the feature or the feature combination further comprising The method according to any one of claims 10 to 12

19. means for broadcasting, in a cell, a first Reference Signal Received Power (RSRP) threshold associated with a feature or feature combination and used for Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) block (SSB) selection; means for receiving a random access preamble transmitted using a first random access opportunity corresponding to an SSB having an RSRP exceeding the first RSRP threshold; comprising wherein the feature is any one of Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing; wherein the feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing; a radio access network node

20. the means for broadcasting is configured to broadcast a plurality of RSRP thresholds including the first RSRP threshold; each of the plurality of RSRP thresholds is associated with one of a plurality of features or one or more combinations of two or more features included in the plurality of features; the plurality of features includes at least two of RedCap, SDT, CovEnh, and Slicing; The radio access network node according to claim 19

21. broadcasting, in a cell, a first Reference Signal Received Power (RSRP) threshold associated with a feature or feature combination and used for Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) block (SSB) selection, and Receiving a random access preamble transmission transmitted using a first random access opportunity corresponding to an SSB having an RSRP exceeding the first RSRP threshold value, comprising, wherein the feature is any one of Reduced Capability (RedCap), Small Data Transmission (SDT), Coverage Enhancement (CovEnh), or Slicing, wherein the feature combination includes at least two of RedCap, SDT, CovEnh, and Slicing, A method performed by a radio access network node.

22. The broadcasting includes broadcasting a plurality of RSRP threshold values including the first RSRP threshold value, wherein each of the plurality of RSRP threshold values is associated with one of a plurality of features or one or more combinations of two or more features included in the plurality of features, wherein the plurality of features includes at least two of RedCap, SDT, CovEnh, and Slicing, The method according to claim 21.

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