WO2024009521A1 - Wireless base station, terminal, and wireless communication system - Google Patents

Abstract

This wireless base station performs communication with a terminal via a wireless communication device connected to the same base station device. When the terminal transitions from a first cell to a second cell that are formed by the wireless communication device, the wireless base station uses Layer 1 functionality to establish a state in which the terminal is connected to both the first cell and the second cell.

Description

Wireless base stations, terminals and wireless communication systems

The present disclosure relates to a wireless base station, a terminal, and a wireless communication system.

The 3rd Generation Partnership Project (3GPP: registered trademark) specifies the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and furthermore specifies the next generation called Beyond 5G, 5G Evolution or 6G. Generation specifications are also being developed.

For example, in 3GPP Release 18, the mobility of terminals (User Equipment, UE) is planned to be expanded (Non-Patent Document 1). Specifically, mobility control at Layer 1 and/or Layer 2 (which may be referred to as L1/L2 Mobility) aims at lower latency, smaller overhead, and shorter downtime than the existing mobility at Layer 3. ) are being considered.

However, when realizing L1/L2 Mobility, there are the following issues. For example, a radio base station (gNB) includes a central unit (CU) and a distributed unit (DU: Distributed Unit), and the UE is connected between multiple DUs (intercells) connected to the same CU. In the case of handover (transition), the medium access control layer (MAC) and/or the radio link control layer (RLC) cannot be reset, and the handover may fail.

Furthermore, existing handovers are triggered based on measurement reports in layer 3 from the UE, but in the case of L1/L2 Mobility, handovers triggered by such measurement reports cannot be performed.

Therefore, the following disclosure was made in view of this situation, and aims to provide a wireless base station, a terminal, and a wireless communication system that can realize more reliable L1/L2 Mobility.

One aspect of the present disclosure includes a communication unit (wireless communication unit 110) that performs communication with a terminal (UE 200) via a wireless communication device (DU) connected to the same base station device (CU), and a control for establishing a state in which the terminal is connected to both the first cell and the second cell using a layer 1 function when the terminal transitions from a first cell to a second cell formed by the device; (control unit 140).

One aspect of the present disclosure includes a control unit (control unit 240) that controls measurement of a cell including a serving cell, and a transmission unit (measurement report unit 220) that transmits a report of the measurement, and the control unit This is a terminal (UE 200) that controls measurements in layer 1 of the serving cell and neighboring cells.

One aspect of the present disclosure is a wireless communication system (wireless communication system 10) including a terminal and a wireless base station, wherein the terminal includes a control unit (control unit 240) that performs measurement of a serving cell, and a control unit (control unit 240) that performs measurement of a serving cell. The wireless base station includes a transmitting unit (measurement reporting unit 220) that transmits a report, the radio base station includes a receiving unit (measurement setting unit 130) that receives the report, and the control unit controls the layer of the serving cell and neighboring cells. 1, and the receiving unit receives the report including the measurement results of the serving cell and the neighboring cells.

FIG. 1 is an overall schematic configuration diagram of a wireless communication system 10. FIG. 2 is a diagram illustrating a configuration example of Inter-DU inter-cell handover. FIG. 3 is a diagram illustrating a configuration example of intra-DU inter-cell handover. FIG. 4 is a functional block diagram of the gNB 100. FIG. 5 is a functional block diagram of the UE 200. FIG. 6 is a diagram illustrating an operation example from a user plane perspective when Intra-DU L1/L2 Mobility or Inter-DU L1/L2 Mobility is applied. FIG. 7 is a diagram illustrating a configuration example (dual connectivity connection) of a cell and a radio link control layer when an L1/L2 Mobility procedure is executed. FIG. 8 is a diagram illustrating a configuration example of a radio link control layer and a packet data convergence protocol layer (user plane) during dual connectivity. FIG. 9 is a diagram illustrating a sequence example of an Inter-DU L1/L2 Mobility procedure based on dual connectivity. FIG. 10 is a diagram illustrating a sequence example of an intra-DU L1/L2 Mobility procedure based on carrier aggregation. FIG. 11 is a diagram illustrating an example of forwarding downlink (DL) data (packets) when the Inter-DU L1/L2 Mobility procedure is executed. FIG. 12 is a diagram illustrating an example of forwarding uplink (UL) data (packets) when the Inter-DU L1/L2 Mobility procedure is executed. FIG. 13 is a diagram illustrating a sequence example of an Inter-DU L1/L2 Mobility procedure based on dual connectivity (part 1 when setting multiple candidate cells to the UE without DC connection in advance). FIG. 14 is a diagram illustrating a sequence example of the Inter-DU L1/L2 Mobility procedure based on dual connectivity (case 2 when setting multiple candidate cells to the UE without DC connection in advance). FIG. 15 is a diagram illustrating an example of the configuration of a cell and a radio link control layer (in a case where a plurality of candidate cells are set in a UE) when an L1/L2 Mobility procedure is executed. FIG. 16 is a diagram illustrating a sequence example of an intra-DU L1/L2 Mobility procedure based on carrier aggregation (part 1 when setting multiple candidate cells to the UE without CA connection in advance). FIG. 17 is a diagram illustrating a sequence example of an intra-DU L1/L2 Mobility procedure based on carrier aggregation (case 2 in which multiple candidate cells are configured in the UE without CA connection in advance). FIG. 18 is a diagram showing an example of the hardware configuration of the gNB 100 and the UE 200. FIG. 19 is a diagram showing an example of the configuration of vehicle 2001.

Hereinafter, embodiments will be described based on the drawings. Note that the same functions and configurations are given the same or similar symbols, and the description thereof will be omitted as appropriate.

(1) Overall schematic configuration of wireless communication system FIG. 1 is an overall schematic configuration diagram of a wireless communication system 10 according to the present embodiment. The radio communication system 10 is a radio communication system according to 5G New Radio (NR), and includes a Next Generation-Radio Access Network 20 (hereinafter referred to as NG-RAN 20) and a terminal 200 (User Equipment 200, hereinafter referred to as UE 200).

Note that the wireless communication system 10 may be a wireless communication system that follows a method called Beyond 5G, 5G Evolution, or 6G, or may include a wireless communication system that follows a method called Long Term Evolution (LTE) or 4G. good. The wireless communication system 10 may support functions related to Industrial Internet of Things (IIoT) and URLLC (Ultra-Reliable and Low Latency Communications).

NG-RAN 20 includes a radio base station 100 (hereinafter referred to as gNB 100). Note that the specific configuration of the wireless communication system 10, including the number of gNBs (eNBs or the like) and UEs, is not limited to the example shown in FIG. 1.

Additionally, the gNB100 may adopt a fronthaul (FH) interface specified by O-RAN (Open Radio Access Network Alliance). gNB100 may include O-DU (O-RAN Distributed Unit) and O-RU (O-RAN Radio Unit). gNB100 can function as a type of NG-RAN node.

NG-RAN20 actually includes multiple NG-RAN Nodes, specifically gNB (or ng-eNB), and is connected to a 5G-compliant core network (5GC, not shown). 5GC may introduce the concept of CUPS (Control and User Plane Separation), which clearly separates the functions of the user plane and control plane.

Access and Mobility Management Function (AMF), which is included in the 5G system architecture and provides access and mobility management functions for UE200, and Session Management Function (SMF), which provides session management functions, are connected to NG-RAN20. be done. Further, a UDM/UDR (Unified Data Management/User Data Repository) may be connected to the AMF and/or the SMF. Note that NG-RAN20 and 5GC may be simply expressed as "networks".

gNB100 is a radio base station that complies with NR, and performs radio communication with UE200 that complies with NR. Note that the gNB 100 may be configured with a CU (Central Unit) and a DU (Distributed Unit), and the DU may be separated from the CU and installed in a geographically different location. Furthermore, the gNBs 100 (gNB-CUs) may be connected by an Xn interface.

gNB100 and UE200 utilize Massive MIMO, which generates a highly directional beam by controlling radio signals transmitted from multiple antenna elements, Carrier Aggregation (CA), which uses multiple component carriers (CC) in a bundle, It is also possible to support dual connectivity (DC), which allows simultaneous communication between the UE and multiple NG-RAN nodes.

In addition, in the wireless communication system 10, not only mobility control of the UE 200 at layer 3 (also referred to as L3 Mobility) but also mobility control at layer 1 and/or layer 2 (L1/L2 Mobility) is applied. You can. L3 Mobility may be interpreted as mobility control at the Radio Resource Control Layer (RRC). On the other hand, L1/L2 Mobility is interpreted as mobility control at the physical layer (PHY), medium access control layer (MAC), radio link control layer (RLC) and packet data convergence protocol layer (PDCP). Good too.

Layer 1 may be interpreted to include lower layers such as PHY. Layer 3 is a layer higher than layer 1. The upper layer may include RRC, and may include at least one of MAC, RLC, and PDCP.

The mobility of the UE 200 may mean the ease of movement and maneuverability of the UE 200 in a broad sense, but in this embodiment, it may mean transition between cells. Transitions between cells may include handovers and cell selection (including cell reselection). Note that the mobility of the UE 200 may mean minimizing call drops, wireless link (including beam) failures, unnecessary handovers, ping-pong situations, and the like.

L1/L2 Mobility, which is a lower layer than L3 Mobility, can achieve lower delay, smaller overhead, shorter interruption time, etc. than L3 Mobility.

Figure 2 shows an example of the configuration of Inter-DU inter-cell handover. FIG. 3 shows a configuration example of intra-DU inter-cell handover.

As mentioned above, the gNB 100 can adopt the CU-DU configuration. As shown in FIG. 2, a plurality of DUs may be connected to one CU, and as shown in FIG. 3, one DU may be connected to one CU. A DU may form one or more cells, specifically cell C1 and cell C2.

For example, as shown in FIG. 2, one DU may form the cell C1, and the other DU may form the cell C2. Alternatively, as shown in FIG. 3, one DU may form cell C1 and cell C2.

Handover between cells as shown in FIG. 2 may be referred to as Inter-DU inter-cell handover. Furthermore, handover between cells as shown in FIG. 3 may be referred to as intra-DU inter-cell handover.

In the case of L3 Mobility, when such handover is performed, the MAC and RLC may be reset and PDCP reconfiguration or data recovery may be performed. In the case of L1/L2 Mobility, the MAC and/or RLC do not necessarily need to be reset (some may be reset).

(2) Functional block configuration of wireless communication system Next, the functional block configuration of the wireless communication system 10 will be explained. Specifically, the functional block configurations of gNB 100 and UE 200 will be explained. FIG. 4 is a functional block diagram of the gNB 100. FIG. 5 is a functional block diagram of the UE 200.

(2.1) gNB100
As shown in FIG. 4, the gNB 100 includes a wireless communication section 110, a handover processing section 120, a measurement setting section 130, and a control section 140.

The wireless communication unit 110 transmits a downlink signal (DL signal) according to NR. Furthermore, the wireless communication unit 110 receives an uplink signal (UL signal) according to the NR.

In this embodiment, the wireless communication unit 110 may constitute a communication unit that communicates with a terminal via a wireless communication device connected to the same base station device. Specifically, the wireless communication unit 110 can communicate with the UE 200 via DUs connected to the same CU.

Note that the CU may be called a central device, aggregation device, etc., and the DU may be called a distribution device, an overhang device, etc.

The handover processing unit 120 executes handover of the UE 200. Specifically, handover processing unit 120 executes handover from the serving cell of UE 200 to another nearby cell.

Note that the serving cell may simply be interpreted as the cell to which the UE 200 is connected, but more precisely, in the case of an RRC_CONNECTED UE for which carrier aggregation (CA) is not set, there is only one serving cell that constitutes the primary cell. Only one. For an RRC_CONNECTED UE configured with CA, the serving cell may be interpreted to refer to a set of one or more cells including the primary cell and all secondary cells.

Additionally, handover may include conditional handover (CHO). The CHO can perform a UE 200-initiated handover when certain execution conditions are met. If CHO is not applicable, normal handover may be performed (may be referred to as CHO recovery). In CHO recovery, the UE 200 performs cell selection after CHO failure, but if a CHO candidate cell is selected, it is possible to reconnect by directly applying the conditional RRCReconfiguration of the cell without sending an RRCRestablishmentRequest to the candidate target cell.

The execution condition may be composed of one or two trigger conditions (CHO events A3/A5 specified in 3GPP TS38.331). A single reference signal (RS) type is triggered and up to two different trigger quantities (e.g. Reference Signal Received Power (RSRP) and Reference Signal Received Quality (RSRQ) ), RSRP and Signal-to-Interference plus Noise power Ratio (SINR), etc.) may be configured at the same time.

The measurement setting unit 130 executes settings for quality measurement of the serving cell and neighboring cells (measurement settings) by the UE 200. Specifically, the measurement configuration unit 130 may perform measurement configuration at layer 3, or measurement configuration at layer 1 and/or layer 2.

The measurement setting unit 130 can notify the UE 200 of the contents of the measurement settings. UE 200 may measure the quality of the serving cell and/or neighboring cells based on the notified measurement settings. The measurement setting unit 130 can receive a measurement report indicating the measurement result of the cell quality from the UE 200. In this embodiment, the measurement setting section 130 constitutes a receiving section that receives the measurement report.

The control unit 140 controls each functional block that configures the gNB 100. In particular, in this embodiment, the control unit 140 can perform control regarding the mobility of the UE 200.

Specifically, the control unit 140 may execute control regarding L3 Mobility and/or control regarding L1/L2 Mobility. For example, regarding L1/L2 Mobility, the control unit 140 controls the layer 1 (and/or layer 2) may be used to establish a state in which the terminal is connected to both the first cell and the second cell.

Here, the state in which the terminal is connected to both the first cell and the second cell may mean dual connectivity (DC) or carrier aggregation (CA).

More specifically, in the case of Intra-CU inter-DU HO, the control unit 140 may execute DC-based L1/L2 Mobility. Furthermore, in the case of Intra-CU intra-DU HO, the control unit 140 may execute L1/L2 Mobility based on CA. The control unit 140 may determine handover (HO) after receiving the layer 1 measurement report from the UE 200.

The type of DC may be Multi-RAT Dual Connectivity (MR-DC), which uses multiple radio access technologies, or NR-NR Dual Connectivity (NR-DC), which uses only NR. In addition, MR-DC may be E-UTRA-NR Dual Connectivity (EN-DC), where the eNB constitutes the master node (MN) and the gNB constitutes the secondary node (SN), or vice versa. -E-UTRA Dual Connectivity (NE-DC) may also be used.

A master cell group (MCG) and a secondary cell group (SCG) may be set in the DC. The MCG may include a primary cell (PCell), and the SCG may include a secondary cell (SCell).

The control unit 140 may put the SCG in an active state and switch between PCell and PSCell, release the SCG after HO is completed, or put it in a deactivated state. Furthermore, the control unit 140 may activate PDCP duplication to operate two PDCPs simultaneously at the time of HO.

Additionally, the SCell may include a primary/secondary cell (PSCell). PSCell is a type of SCell, but may be interpreted as a special SCell that has functions equivalent to PCell. Similar to PCell, PSCell may perform functions such as PUCCH (Physical Uplink Control Channel) transmission, contention-based random access procedure (CBRA), and Radio Link Monitoring (downlink radio quality monitoring) functions. .

The RA procedure may be simply read as the Random Access Channel (RACH). The RA procedure (RACH) may include a 2-step RACH and a 4-step RACH.

The RA procedure (RACH) may include 2-step RACH and 4-step RACH. In the two-step RACH, messages (MSG) A and B (Random Access Preamble, Contention Resolution/Random Access Response) may be sent and received. In the 4-step RACH, MSGs 1 to 4 (Random Access Preamble, Random Access Response, Scheduled Transmission, Contention Resolution) may be transmitted and received.

Note that in this embodiment, the channels include a control channel and a data channel. Control channels include PDCCH (Physical Downlink Control Channel), PUCCH (Physical Uplink Control Channel), PRACH (Physical Random Access Channel), PBCH (Physical Broadcast Channel), and the like.

Additionally, data channels include PDSCH (Physical Downlink Shared Channel), PUSCH (Physical Uplink Shared Channel), and the like.

Reference signals include Demodulation reference signal (DMRS), Sounding Reference Signal (SRS), Phase Tracking Reference Signal (PTRS), Channel State Information-Reference Signal (CSI-RS), etc. Contains channels and reference signals. Data may also refer to data transmitted via a data channel.

Further, the control unit 140 causes the PDCP on the CU (base station device) side to transmit unacknowledged data in the RLC (first radio link control layer) on the first cell side of the DU, and The PDCP may cause the RLC (second radio link control layer) on the second cell side of the DU to transmit the data. Un-Acked data may be interpreted as data for which the gNB 100 has not received an acknowledgment. The data may be read as a packet, a protocol data unit (PDU), or the like.

Furthermore, after resetting the first radio link control layer, the RLC (first radio link control layer) on the first cell side of the DU transmits the data to the RLC (second radio link control layer) on the second cell side of the DU. You may resend it. Alternatively, the data may be retransmitted to the second radio link control layer without resetting the first radio link control layer, and after the data is retransmitted, the first radio link control layer may be reset. Note that there may be a time when both the RLC on the first cell side of the DU and the RLC on the second cell side of the DU are set.

(2.2) UE200
As shown in FIG. 5, the UE 200 includes a wireless communication section 210, a measurement reporting section 220, a handover execution section 230, and a control section 240.

The wireless communication unit 210 transmits an uplink signal (UL signal) according to NR. Furthermore, the wireless communication unit 210 receives an uplink signal (DL signal) according to NR.

The measurement reporting unit 220 can measure the quality of the serving cell of the UE 200 and the neighboring cells of the serving cell, and can report the measurement results (Measurement Report) to the network. The measurement reporting unit 220 may perform measurement reporting of the source cell and target cell upon handover. In this embodiment, the measurement report section 220 constitutes a transmitter that transmits a measurement report.

The quality of the measurement target may be, for example, the quality included in the Measurement Report specified in 3GPP TS38.331 (for example, Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ)), etc.

The measurement reporting unit 220 may perform not only measurements at layer 3 but also measurements at layer 1 (and/or layer 2) of the serving cell and neighboring cells. Measurement at layer 1 and/or layer 2 is interpreted as measurement using layer functions in at least one of PHY, MAC, RLC, PDCP, and reporting of the measurement results, similar to L1/L2 Mobility. good.

The handover execution unit 230 executes handover of the UE 200. Specifically, the handover execution unit 230 may execute the handover to the transition destination cell (NG-RAN node) based on the control by the gNB 100.

Furthermore, the handover execution unit 230 can execute processing related to normal handover (legacy handover) and conditional handover (CHO).

In the case of CHO, the handover execution unit 230 may transition to a candidate cell when an execution condition is met. As described above, the execution conditions may be determined based on the quality of the reference signal (RS), specifically, the value of RSRP, RSRQ, or SINR.

Furthermore, the transition destination of CHO may not be accompanied by an SCG, or may be accompanied by an SCG. In other words, the cell to which the CHO transitions may be a single cell, or may be composed of a plurality of cells (which may be read as a cell group) according to the DC.

The control unit 240 controls each functional block that configures the UE 200. Specifically, the control unit 240 can perform control regarding registration of the UE 200 with the network (standby in a specific cell), measurement reporting, and handover of the UE 200.

The control unit 240 controls measurement of cells including the serving cell. Specifically, the control unit 240 can control measurements at layer 1 (and/or layer 2) of the serving cell and neighboring cells. In other words, the control unit 240 can perform measurements of the serving cell and neighboring cells (which may also be referred to as L1 measurements) using the layer 1 (and/or layer 2) functions.

When a failure occurs in layer 1 (and/or layer 2), the control unit 240 may notify the RRC of its own station of the failure information. Note that the failure information may be notified to a layer other than RRC (for example, MAC, RLC, PDCP). The failure information includes, but is not limited to, the identification information (ID) of the source cell (handover source), the identification information (ID) of the target cell (handover destination), and/or the quality of the cell (or beam). May be included.

(3) Operation of wireless communication system Next, the operation of the wireless communication system 10 will be explained. Specifically, operations related to mobility control (L1/L2 Mobility) at layer 1 and/or layer 2 will be described.

(3.1) Operation example 1
(3.1.1) Issues In intra-CU inter-cell handover (intra-DU inter-cell handover (HO) or inter-DU inter-cell handover (HO)) according to conventional L3 Mobility, MAC and RLC is reset, and for PDCP, PDCP re-establishment or PDCP data recovery is performed. PDCP data recovery refers to the related retransmission of PDCP data PDUs that were previously sent to a re-established or released AM (Acknowledged Mode) RLC entity and whose successful delivery has not been acknowledged by lower layers. This may be interpreted as executing in ascending order of the COUNT values.

In the case of L1/L2 Mobility, in Intra-DU/inter-DU inter-cell HO, MAC and RLC may not be reset, or may be partially reset, and normal handover may not be possible. In particular, when a part of the layer is to be reset, the problem is which part should be reset.

(3.1.2) Solution Below, we will show an example of a solution from the user plane (U plane) perspective that solves the above-mentioned problems.

(3.1.2.1) Intra-DU L1/L2 Mobility or Inter-DU L1/L2 Mobility
FIG. 6 shows an operation example from a user plane perspective when Intra-DU L1/L2 Mobility or Inter-DU L1/L2 Mobility is applied.

As shown in FIG. 6, some functions (procedures) of the MAC may be reset in Intra-DU L1/L2 Mobility or Inter-DU L1/L2 Mobility. Furthermore, not only the MAC but also some functions (procedures) of the RLC may be reset.

When resetting some functions of the MAC, for example, among the functions (procedures) of the MAC shown below, functions (procedures) other than those enclosed in [] may be reset.

・[initialize Bj for each logical channel to zero;]
・stop (if running) all timers;
・consider all timeAlignmentTimers as expired and perform the corresponding actions in clause 5.2;
・[set the NDIs for all uplink HARQ processes to the value 0]
・stop, if any, ongoing RACH procedure;
・discard explicitly signaled contention-free Random Access Resources, if any
・[flush Msg3 buffer;]
・cancel, if any, triggered Scheduling Request procedure;
・cancel, if any, triggered Buffer Status Reporting procedure;
・cancel, if any, triggered Power Headroom Reporting procedure;
・[flush the soft buffers for all DL HARQ processes;]
・[for each DL HARQ process, consider the next received transmission for a TB as the very first transmission;]
・release, if any, Temporary C-RNTI;
・reset BFI_COUNTER.
Functions (procedures) enclosed in [ ] are interpreted as U-plane functions (procedures), and functions (procedures) not enclosed in [ ] are interpreted as control-plane (C-plane) functions (procedures). You can. In other words, the C-plane functions (procedures) may be reset.

(3.1.2.2) Intra-CU inter-DU HO or Intra-CU intra-DU HO
In the case of Intra-CU inter-DU HO (see Figure 2), DC based L1/L2 Mobility may be performed. Furthermore, in the case of Intra-CU intra-DU HO (see FIG. 3), CA based L1/L2 Mobility may be executed.

Specifically, a DC state may be established between the source DU and candidate target DU. The candidate target DU may be interpreted as a DU (cell) that can be a candidate for handover.

In the case of Intra-DU HO, a candidate target cell may be added as an SCell within the DU. Alternatively, the candidate target cell configuration may be preset in the UE without establishing a DC state. The configuration may be instructed to the UE by a message such as MAC or RRC, or may be set in the UE in advance.

Furthermore, in order to save power and use resources effectively, the SCG and/or SCell may be placed in a deactivated state. The inactive state may be interpreted as a state in which the settings of the cell (or cell group) are released, or a state in which all settings are not released and some settings are maintained.

The SCG may be set to the DRX (Discontinuous Reception) state, or may not be set to the deactivated state or the DRX state.

Additionally, the Source DU may determine the HO after receiving the quality measurement result (L1 measurement report) from the UE. Specifically, L1/L2 Mobility (HO) may be performed by any of the following.

- After the UE receives the L1L2 mobility command from the gNB - When the UE does not receive the HO instruction from the gNB and satisfies the predetermined execution conditions (event X) L1/L2 Mobility (HO) is executed using the L1L2 mobility command This may be done at the same time as receiving the L1L2 mobility command or satisfying event X, or within a predetermined time after receiving the L1L2 mobility command or satisfying event X.

The predetermined execution condition (event X) may be, for example, any of the following.

- The quality of the target cell is better than the source cell by the offset - The quality of the target cell is better than a predetermined threshold - The quality of the source cell is worse than a predetermined threshold and the quality of the target cell is better than a predetermined threshold Furthermore, in the case of DC based L1/L2 Mobility, at the time of HO, the SCG may be brought into an activated state to switch between PCell and PSCell. In the case of CA based L1/L2 Mobility, at the time of HO, the cell may be brought into the activated state and switched between PCell and SCell, or between PSCell and SCell.

In this case, PDCP duplication may be activated during HO. Further, the RLC of the source DU may transfer unacknowledged data to the PDCP on the CU side, and the PDCP on the CU side may transfer the data to the RLC of the target DU. Specifically, the source RLC may resend unacknowledged data after being reset, or the source RLC may transfer unacknowledged data to the target RLC without resetting immediately and then reset. good.

Here, the RLC of the source DU and the RLC of the target DU may be in a state of duplication (both active) temporarily. The RLC of the source DU may be reset after receiving the transmission completion indication from the CU to the target RLC.

In addition, the CU refers to the highest delivered sequence number/highest transmitted sequence number (highest delivered/highest transmitted) based on the DDDS (Downlink Data Delivery status) feedback from the Source DU, and the delivery to the UE is not successful. The PDU may be determined. The CU may retransmit PDUs that are not successfully delivered by the source DU to the target DU. After HO is completed, the SCG may be released or placed in a deactivated state.

After completing L1/L2 Mobility, the UE may retain the configuration of the candidate target cell without resetting it, or may retain the configuration of the source cell without resetting it. This has the advantage that if the quality of the target cell is poor immediately after handover to the target cell, it can be immediately handed over to the source cell or another candidate target cell. The UE may release the configuration of the candidate target cell or the source cell after receiving an instruction to release the configuration of the candidate target cell or the source cell through layer 1 and/or layer 2 signaling or an RRC message from the network.

FIG. 7 shows an example of the configuration of the cell and radio link control layer (dual connectivity connection) when executing the L1/L2 Mobility procedure. As shown in FIG. 7, in the gNB 100, RLC for each cell is configured, and among them, RLC for PCell may be activated. The UE may perform HO to the PSCell or SCell. PCell and PSCell, and PSCell and SCell may be switched as described above.

FIG. 8 shows an example of the configuration of the radio link control layer and packet data convergence protocol layer (user plane) during dual connectivity. As shown in FIG. 8, the PDCP of the gNB 100 may receive measurement reports from the UE via the source RLC. The PDCP may retransmit unacknowledged data via the target RLC.

Figure 9 shows a sequence example of the Inter-DU L1/L2 Mobility procedure based on dual connectivity. As shown in FIG. 9, the CU establishes an Intra-CU DC in response to a measurement report from the UE, and puts the PSCell in a deactivated state (S1).

The UE transmits the L1 measurement report, and the gNB100 (CU and DU) switches the PSCell to the PCell, switches the PCell to the PSCell, and completes L1/L2 Mobility (S2). Note that when switching a PSCell to a PCell and a PCell to a PSCell, the MAC entity may be partially reset, or the MAC entity may not be reset.

FIG. 10 shows a sequence example of the Intra-DU L1/L2 Mobility procedure based on carrier aggregation. As shown in FIG. 10, in the case of CA based Intra-DU L1/L2 Mobility, SCell may be switched to PCell (PSCell), and PCell (PSCell) may be switched to SCell. Note that when switching SCell to PCell (PSCell) and switching PCell (PSCell) to SCell, the MAC entity may be partially reset, or the MAC entity may not be reset.

FIG. 11 shows an example of forwarding downlink (DL) data (packets) when the Inter-DU L1/L2 Mobility procedure is executed. The example in FIG. 11 shows a state in which "3" packets (which may also be PDUs) are not delivered to the UE. PDCP of the gNB 100 (CU) may forward packet “3” to the target RLC. Packet "3" is sent to the UE via the target DU. Alternatively, PDCP data recovery may be executed in the PDCP of the gNB to recover the un-Acked "3" packet and forward it to the target RLC.

FIG. 12 shows an example of uplink (UL) data (packet) transfer when the Inter-DU L1/L2 Mobility procedure is executed. In the example of FIG. 12, similarly to FIG. 11, a state is shown in which "3" packets (which may be PDUs) are not delivered to the gNB 100. The PDCP of the UE 200 may forward packet "3" to the RLC for the target DU. Packet “3” is transmitted to gNB 100 via RLC for target DU. Alternatively, PDCP data recovery may be executed in the PDCP of the UE to recover the un-Acked "3" packet, and the "3" packet may be forwarded to the RLC for the target DU.

FIG. 13 shows a sequence example of the Inter-DU L1/L2 Mobility procedure based on dual connectivity (Part 1 when setting multiple candidate cells to the UE without DC connection in advance). Specifically, as shown in FIG. 13, multiple candidate cells (multiple candidate cells config) are configured in the UE without DC connection in advance. Such an operation has some similarities with CHO and may be interpreted as CHO.

Note that the L1L2 mobility completed command indicating completion of L1/L2 mobility may be a layer 1 or layer 2 message. For example, it may be PUCCH or MAC CE (Control Element). Alternatively, HARQ (hybrid automatic repeat request) Ack may be used.

FIG. 14 shows a sequence example of the Inter-DU L1/L2 Mobility procedure based on dual connectivity (case 2 when setting multiple candidate cells to the UE without DC connection in advance). As shown in FIG. 14, the UE may monitor the execution conditions (event In this case, as in FIG. 13, the L1L2 mobility completed command may be PUCCH or MAC CE.

FIG. 15 shows an example of the configuration of cells and radio link control layers (when multiple candidate cells are set in the UE) when executing the L1/L2 Mobility procedure. As shown in FIG. 15, in the gNB 100, RLCs for a source cell and a plurality of candidate cells are configured, and the RLC for the source cell may be activated.

FIG. 16 shows a sequence example of an intra-DU L1/L2 Mobility procedure based on carrier aggregation (part 1 when setting multiple candidate cells to the UE without CA connection in advance). As shown in FIG. 16, multiple candidate cells (multiple candidate cells config) are configured in the UE without DC connection in advance.

Note that, similarly to FIG. 13, the L1L2 mobility completed command indicating completion of L1/L2 Mobility may be a layer 1 or layer 2 message. For example, it may be PUCCH or MAC CE (Control Element). Alternatively, HARQ (hybrid automatic repeat request) Ack may be used.

FIG. 17 shows a sequence example of the Intra-DU L1/L2 Mobility procedure based on carrier aggregation (case 2 when multiple candidate cells are set in the UE without CA connection in advance).

As shown in FIG. 17, the UE monitors the execution condition (event In this case, as in FIG. 16, the L1L2 mobility completed command may be PUCCH or MAC CE.

According to operation example 1 explained above, by applying measurements at layer 1 and messages at layer 1 and/or layer 2, the CU-DU configuration is adopted and the measurement at layer 1 and/or layer 2 is performed. UE mobility control can be achieved more reliably. Thereby, lower delay, less overhead and shorter downtime may be achieved with respect to UE mobility control, especially in the U-plane.

(3.2) Operation example 2
In operation example 1, the operation was mainly explained from the U-plane perspective, but below, the operation from the C-plane perspective will be mainly explained.

(3.2.1) Issues Regarding the C-plane of L1/L2 Mobility, the following issues need to be considered.

・How to specify the frequency for L1 measurement ・Whether or not averaging is required when reporting L1 measurement ・Whether or not an event that triggers L1/L2 Mobility is necessary ・Timer settings to manage L1/L2 Mobility ・Requirements for RRC in the event of a failure Notification - Necessity of reconnection in the event of a failure or necessity of failure recognition in RRC - Necessity of reconnection in the event of a DC based L1/L2 Mobility failure - CU-DU connection during RACH-less L1/L2 Mobility Necessity of signaling?

(3.2.2) Solution Conventional L1 measurement basically only supports measurement of serving cells (which may include PCell, PSCell, and SCell). Cell identification information (Cell ID) at the time of measurement reporting is specified by servCellIndex, which is an RRC parameter.

In order to support L1/L2 mobility, specifically L1L2 inter-cell mobility, L1 measurement may be able to measure not only the serving cell but also neighboring cells.

In this case, measObject, which is a parameter indicating the measurement target, may specify the frequency of L1 measurement. Alternatively, a new information element (IE) that specifies the frequency of L1 measurement may be set. Cell identification information (Cell ID) may be specified by PCI (Physical Cell ID) at the time of measurement report.

Note that instead of the frequency, a resource block, resource block group, subcarrier, BWP (Bandwidth part), subchannel, etc. may be specified.

In the case of L1 RSRP, the value fluctuates rapidly, so there is a risk of a ping-pong situation (repeated HO). Therefore, in order to prevent such a situation, the UE may report L1 RSRP after averaging the measured RSRP values.

Additionally, for example, the following new events may be defined for L1/L2 Mobility. The MAC entity may manage the event.

・Event X: Neighbor becomes amount of offset better than Pcell/PScell (expressed by formula: Mn > Mp + Off)
Note that event X may be, for example, any of the following.

- The quality of the target cell is better than the source cell by the offset - The quality of the target cell is better than a predetermined threshold - The quality of the source cell is worse than a predetermined threshold and the quality of the target cell is better than a predetermined threshold Note that "Neighbor" may be called a target cell or a Candidate target cell. PCell/PSCell may also be called a source cell.

Alternatively, a new timer may be defined for L1/L2 Mobility. Such a timer may be similar to the existing tire T304. Timer T304 is started when an RRCReconfiguration message with reconfigurationWithSync is received, or when performing a conditional reconfiguration, i.e. when applying a stored RRCReconfiguration message with reconfigurationWithSync, and the successful completion of a random access on the corresponding SpCell. May be stopped upon completion.

The MAC entity may manage the timer. The CU may start the timer when receiving the L1L2 mobility command from the source DU and stop it when the random access (RACH) with the target DU is successful. When the timer expires, L1/L2 Mobility may be determined to be faulty.

L1/L2 Mobility failure information may be notified to RRC. Specifically, any of the PHY, MAC, RLC, or PDCP may notify the RRC of the failure information. The failure information may include the identification information (ID) of the source cell (handover source), the identification information (ID) of the target cell (handover destination), and/or the quality of the cell (for example, SIR). .

Additionally, when an L1/L2 Mobility failure occurs, the RRC reestablishment procedure may be triggered directly. Specifically, in the event of a DC based L1/L2 Mobility failure, reconnection may be performed using the PCI of the source cell (PCell) and C-RNTI (Cell Radio Network Temporary Identifier). Alternatively, reconnection may be performed using the PCI and C-RNTI of the target cell (PSCell).

When an L1/L2 Mobility failure occurs, the UE selects a cell, and if the UE has the configuration of the selected cell, the UE directly applies the configuration of the cell without sending an RRC reestablishment request to the network. You may.

Alternatively, if an L1/L2 Mobility failure occurs, it may fall back to the conventional L3 Mobility procedure.

In addition, in DC based L1/L2 Mobility, if a failure occurs in the target cell (MCG) and the source cell (SCG) is in the deactivated state, the UE performs RACH in the source cell (SCG) and activates the SCG. You may also do so. This allows you to avoid RRC reestablishment.

Alternatively, the CU obtains the transmission timing difference between the target cell and the source cell and the TA (Timing Advance) value of the target cell from the DU, and performs RACH-less with the UE. , the UE may be connected to the target cell. The timing difference and TA values of the target cell and source cell may be sent from the target DU to the CU, and if possible, from the source DU to the CU. .The CU may also send the timing difference and TA value to the source DU.

According to the operation example 2 explained above, by clarifying the measurement related to L1/L2 Mobility in the C plane and the operation in the event of a failure, the UE at layer 1 and/or layer 2 can be mobility control can be achieved more reliably. Thereby, lower delay, less overhead and shorter downtime can be achieved for UE mobility control.

Note that in the operation example described above, the name L1/L2 Mobility was used, but L1/L2 Mobility may be a provisional name or may be called by another similar name (for example, lower layer mobility). Furthermore, resetting the RLC may be interpreted as synonymous with stopping, restarting, initializing, and the like.

(4) Effects and Effects According to the embodiment described above, the detailed operations of the UE and network in the U-plane and C-plane when L1/L2 Mobility is applied are clarified, and L1/L2 Mobility can be realized more reliably. obtain.

(5) Other Embodiments Although the embodiments have been described above, it is obvious to those skilled in the art that the embodiments are not limited to the description of the embodiments, and that various modifications and improvements can be made.

For example, in the above description, the words configure, activate, update, indicate, enable, specify, and select may be used interchangeably. good. Similarly, link, associate, correspond, and map may be used interchangeably; allocate, assign, and monitor. , map may also be read interchangeably.

Further, the terms "specific", "dedicated", "UE specific", and "UE individual" may be interchanged. Similarly, common, shared, group-common, UE-common, and UE-shared may be interchanged.

Furthermore, the block configuration diagrams (FIGS. 4 and 5) used to explain the embodiments described above show blocks in functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using one physically or logically coupled device, or may be realized using two or more physically or logically separated devices directly or indirectly (e.g. , wired, wireless, etc.) and may be realized using a plurality of these devices. The functional block may be realized by combining software with the one device or the plurality of devices.

Functions include judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, These include, but are not limited to, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assigning. I can't do it. For example, a functional block (configuration unit) that performs transmission is called a transmitting unit or a transmitter. In either case, as described above, the implementation method is not particularly limited.

Furthermore, the gNB 100 and UE 200 (the devices) described above may function as a computer that performs processing of the wireless communication method of the present disclosure. FIG. 18 is a diagram showing an example of the hardware configuration of the device. As shown in FIG. 18, the device may be configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

Note that in the following description, the word "apparatus" can be read as a circuit, a device, a unit, etc. The hardware configuration of the device may include one or more of the devices shown in the figure, or may not include some of the devices.

Each functional block of the device (see FIGS. 4 and 5) is realized by any hardware element of the computer device or a combination of hardware elements.

In addition, each function in the device is performed by loading predetermined software (programs) onto hardware such as the processor 1001 and memory 1002, so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls the memory This is realized by controlling at least one of data reading and writing in the storage 1002 and the storage 1003.

The processor 1001, for example, operates an operating system to control the entire computer. The processor 1001 may be configured by a central processing unit (CPU) that includes interfaces with peripheral devices, a control device, an arithmetic device, registers, and the like.

Furthermore, the processor 1001 reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 to the memory 1002, and executes various processes according to these. As the program, a program that causes a computer to execute at least part of the operations described in the above embodiments is used. Further, the various processes described above may be executed by one processor 1001, or may be executed by two or more processors 1001 simultaneously or sequentially. Processor 1001 may be implemented by one or more chips. Note that the program may be transmitted from a network via a telecommunications line.

The memory 1002 is a computer-readable recording medium, and includes at least one of Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), Random Access Memory (RAM), etc. may be done. Memory 1002 may be called a register, cache, main memory, or the like. The memory 1002 can store programs (program codes), software modules, etc. that can execute a method according to an embodiment of the present disclosure.

The storage 1003 is a computer-readable recording medium, such as an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (such as a compact disk, a digital versatile disk, or a Blu-ray disk). (registered trademark disk), smart card, flash memory (eg, card, stick, key drive), floppy disk, magnetic strip, etc. Storage 1003 may also be called auxiliary storage. The above-mentioned recording medium may be, for example, a database including at least one of memory 1002 and storage 1003, a server, or other suitable medium.

The communication device 1004 is hardware (transmission/reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, network controller, network card, communication module, etc.

The communication device 1004 includes, for example, a high frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). It may be composed of.

The input device 1005 is an input device (eg, keyboard, mouse, microphone, switch, button, sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs output to the outside. Note that the input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

Further, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses for each device.

Furthermore, the device includes hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA). A part or all of each functional block may be realized by the hardware. For example, processor 1001 may be implemented using at least one of these hardwares.

Furthermore, the notification of information is not limited to the aspects/embodiments described in this disclosure, and may be performed using other methods. For example, information notification can be performed using physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), upper layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination thereof. RRC signaling may also be referred to as RRC messages, such as RRC Connection Setup (RRC Connection Setup). ) message, RRC Connection Reconfiguration message, etc.

Each aspect/embodiment described in this disclosure includes Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system ( 5G), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)) , IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), and other appropriate systems and next-generation systems enhanced based on these. may be applied to. Furthermore, a combination of multiple systems (for example, a combination of at least one of LTE and LTE-A with 5G) may be applied.

The order of the processing procedures, sequences, flowcharts, etc. of each aspect/embodiment described in this disclosure may be changed as long as there is no contradiction. For example, the methods described in this disclosure use an example order to present elements of the various steps and are not limited to the particular order presented.

In some cases, the specific operations performed by the base station in this disclosure may be performed by its upper node. In a network consisting of one or more network nodes including a base station, various operations performed for communication with a terminal are performed by the base station and other network nodes other than the base station (e.g., MME or It is clear that this can be done by at least one of the following: (conceivable, but not limited to) S-GW, etc.). Although the case where there is one network node other than the base station is illustrated above, it may be a combination of multiple other network nodes (for example, MME and S-GW).

Information, signals (information, etc.) can be output from an upper layer (or lower layer) to a lower layer (or upper layer). It may be input/output via multiple network nodes.

The input/output information may be stored in a specific location (for example, memory) or may be managed using a management table. Information that is input and output may be overwritten, updated, or additionally written. The output information may be deleted. The input information may be sent to other devices.

Judgment may be made using a value expressed by 1 bit (0 or 1), a truth value (Boolean: true or false), or a comparison of numerical values (for example, a predetermined value). (comparison with a value).

Each aspect/embodiment described in the present disclosure may be used alone, in combination, or may be switched and used in accordance with execution. In addition, notification of prescribed information (for example, notification of "X") is not limited to being done explicitly, but may also be done implicitly (for example, not notifying the prescribed information). Good too.

Software includes instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, whether referred to as software, firmware, middleware, microcode, hardware description language, or by any other name. , should be broadly construed to mean an application, software application, software package, routine, subroutine, object, executable, thread of execution, procedure, function, etc.

Additionally, software, instructions, information, etc. may be sent and received via a transmission medium. For example, if the software uses wired technology (coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), etc.) and/or wireless technology (infrared, microwave, etc.) to When transmitted from a server or other remote source, these wired and/or wireless technologies are included within the definition of transmission medium.

The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may refer to voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of the foregoing. It may also be represented by a combination of

Note that terms explained in this disclosure and terms necessary for understanding this disclosure may be replaced with terms that have the same or similar meanings. For example, at least one of the channel and the symbol may be a signal. Also, the signal may be a message. Further, a component carrier (CC) may also be called a carrier frequency, cell, frequency carrier, etc.

As used in this disclosure, the terms "system" and "network" are used interchangeably.

In addition, the information, parameters, etc. described in this disclosure may be expressed using absolute values, relative values from a predetermined value, or using other corresponding information. may be expressed. For example, radio resources may be indicated by an index.

The names used for the parameters mentioned above are not restrictive in any respect. Furthermore, the mathematical formulas etc. using these parameters may differ from those explicitly disclosed in this disclosure. Since the various channels (e.g. PUCCH, PDCCH, etc.) and information elements can be identified by any suitable designation, the various names assigned to these various channels and information elements are in no way exclusive designations. isn't it.

In this disclosure, "base station (BS)", "wireless base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", " "access point", "transmission point", "reception point", "transmission/reception point", "cell", "sector", "cell group", " The terms "carrier", "component carrier", etc. may be used interchangeably. A base station is sometimes referred to by terms such as macrocell, small cell, femtocell, and picocell.

A base station can accommodate one or more (eg, three) cells (also called sectors). If a base station accommodates multiple cells, the overall coverage area of the base station can be partitioned into multiple smaller areas, and each smaller area is divided into multiple subsystems (e.g., small indoor base stations (Remote Radio Communication services can also be provided by Head: RRH).

The term "cell" or "sector" refers to part or all of the coverage area of a base station and/or base station subsystem that provides communication services in this coverage.

In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably. .

A mobile station is defined by a person skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless It may also be referred to as a terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

At least one of a base station and a mobile station may be called a transmitting device, a receiving device, a communication device, etc. Note that at least one of the base station and the mobile station may be a device mounted on a mobile body, the mobile body itself, or the like. The moving object may be a vehicle (for example, a car, an airplane, etc.), an unmanned moving object (for example, a drone, a self-driving car, etc.), or a robot (manned or unmanned). ). Note that at least one of the base station and the mobile station includes devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

Additionally, the base station in the present disclosure may be read as a mobile station (user terminal, hereinafter the same). For example, communication between a base station and a mobile station is replaced with communication between multiple mobile stations (for example, it may be called Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). Regarding the configuration, each aspect/embodiment of the present disclosure may be applied. In this case, the mobile station may have the functions that the base station has. Further, words such as "up" and "down" may be replaced with words corresponding to inter-terminal communication (for example, "side"). For example, uplink channels, downlink channels, etc. may be replaced with side channels.

Similarly, the mobile station in the present disclosure may be read as a base station. In this case, the base station may have the functions that the mobile station has.
A radio frame may be composed of one or more frames in the time domain. Each frame or frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (eg, 1 ms) that does not depend on numerology.

The numerology may be a communication parameter applied to at least one of transmission and reception of a certain signal or channel. Numerology includes, for example, subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, transmission and reception. It may also indicate at least one of a specific filtering process performed by the device in the frequency domain, a specific windowing process performed by the transceiver in the time domain, etc.

A slot may be composed of one or more symbols (Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.) in the time domain. A slot may be a unit of time based on numerology.

A slot may include multiple mini-slots. Each minislot may be made up of one or more symbols in the time domain. Furthermore, a mini-slot may also be called a sub-slot. A minislot may be made up of fewer symbols than a slot. PDSCH (or PUSCH) transmitted in time units larger than minislots may be referred to as PDSCH (or PUSCH) mapping type A. PDSCH (or PUSCH) transmitted using minislots may be referred to as PDSCH (or PUSCH) mapping type B.

Radio frames, subframes, slots, minislots, and symbols all represent time units when transmitting signals. Other names may be used for the radio frame, subframe, slot, minislot, and symbol.

For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, and one slot or minislot may be called a TTI. In other words, at least one of the subframe and TTI may be a subframe (1ms) in existing LTE, a period shorter than 1ms (for example, 1-13 symbols), or a period longer than 1ms. It may be. Note that the unit representing TTI may be called a slot, minislot, etc. instead of a subframe.

Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (frequency bandwidth, transmission power, etc. that can be used by each user terminal) to each user terminal on a TTI basis. Note that the definition of TTI is not limited to this.

The TTI may be a unit of transmission time such as a channel-coded data packet (transport block), a code block, or a codeword, or may be a unit of processing such as scheduling or link adaptation. Note that when a TTI is given, the time interval (for example, the number of symbols) to which transport blocks, code blocks, code words, etc. are actually mapped may be shorter than the TTI.

Note that when one slot or one minislot is called a TTI, one or more TTIs (that is, one or more slots or one or more minislots) may be the minimum time unit for scheduling. Further, the number of slots (minislot number) that constitutes the minimum time unit of the scheduling may be controlled.

A TTI with a time length of 1 ms may be called a normal TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, normal subframe, normal subframe, long subframe, slot, etc. A TTI that is shorter than the normal TTI may be referred to as a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

Note that long TTI (e.g., normal TTI, subframe, etc.) may be read as TTI with a time length exceeding 1ms, and short TTI (e.g., shortened TTI, etc.) may be interpreted as TTI with a time length of less than the long TTI and 1ms. It may also be read as a TTI having a TTI length of the above length.

A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more continuous subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of the new merology, and may be 12, for example. The number of subcarriers included in an RB may be determined based on newerology.

Additionally, the time domain of an RB may include one or more symbols and may be one slot, one minislot, one subframe, or one TTI in length. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

Note that one or more RBs are classified into physical resource blocks (Physical RBs: PRBs), sub-carrier groups (Sub-Carrier Groups: SCGs), resource element groups (Resource Element Groups: REGs), PRB pairs, RB pairs, etc. May be called.

Additionally, a resource block may be configured by one or more resource elements (RE). For example, 1 RE may be a radio resource region of 1 subcarrier and 1 symbol.

Bandwidth Part (BWP) (also called partial bandwidth, etc.) refers to a subset of contiguous common resource blocks for a certain numerology in a certain carrier. good. Here, the common RB may be specified by an RB index based on a common reference point of the carrier. PRBs may be defined in a BWP and numbered within that BWP.

BWP may include BWP for UL (UL BWP) and BWP for DL (DL BWP). One or more BWPs may be configured within one carrier for the UE.

At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal/channel outside the active BWP. Note that "cell", "carrier", etc. in the present disclosure may be replaced with "BWP".

The structures of radio frames, subframes, slots, minislots, symbols, etc. described above are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of symbols included in an RB, The number of subcarriers, the number of symbols within a TTI, the symbol length, the cyclic prefix (CP) length, and other configurations can be changed in various ways.

The terms "connected", "coupled", or any variations thereof, refer to any connection or coupling, direct or indirect, between two or more elements and to each other. It can include the presence of one or more intermediate elements between two elements that are "connected" or "coupled." The bonds or connections between elements may be physical, logical, or a combination thereof. For example, "connection" may be replaced with "access." As used in this disclosure, two elements may include one or more electrical wires, cables, and/or printed electrical connections, as well as in the radio frequency domain, as some non-limiting and non-inclusive examples. , electromagnetic energy having wavelengths in the microwave and optical (both visible and non-visible) ranges, and the like.

The reference signal can also be abbreviated as Reference Signal (RS), and may be called a pilot depending on the applied standard.

As used in this disclosure, the phrase "based on" does not mean "based solely on" unless explicitly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

"Means" in the configurations of each of the above devices may be replaced with "unit", "circuit", "device", etc.

As used in this disclosure, any reference to elements using the designations "first," "second," etc. does not generally limit the amount or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Thus, reference to a first and second element does not imply that only two elements may be employed therein or that the first element must precede the second element in any way.

Where "include", "including" and variations thereof are used in this disclosure, these terms, like the term "comprising," are inclusive. It is intended that Furthermore, the term "or" as used in this disclosure is not intended to be exclusive or.

In the present disclosure, when articles are added by translation, such as a, an, and the in English, the present disclosure may include that the nouns following these articles are plural.

As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of operations. "Judgment" and "decision" include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, search, and inquiry. (e.g., searching in a table, database, or other data structure), and regarding an ascertaining as a "judgment" or "decision." In addition, "judgment" and "decision" refer to receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, and access. (accessing) (e.g., accessing data in memory) may include considering something as a "judgment" or "decision." In addition, "judgment" and "decision" refer to resolving, selecting, choosing, establishing, comparing, etc. as "judgment" and "decision". may be included. In other words, "judgment" and "decision" may include regarding some action as having been "judged" or "determined." Further, "judgment (decision)" may be read as "assuming", "expecting", "considering", etc.

In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." Note that the term may also mean that "A and B are each different from C". Terms such as "separate" and "coupled" may also be interpreted similarly to "different."

FIG. 19 shows an example of the configuration of the vehicle 2001. As shown in FIG. 19, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, Equipped with various sensors 2021 to 2029, an information service section 2012, and a communication module 2013.

The drive unit 2002 includes, for example, an engine, a motor, or a hybrid of an engine and a motor.
The steering unit 2003 includes at least a steering wheel (also referred to as a steering wheel), and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.
The electronic control unit 2010 includes a microprocessor 2031, memory (ROM, RAM) 2032, and communication port (IO port) 2033. Signals from various sensors 2021 to 2027 provided in the vehicle are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

Signals from various sensors 2021 to 2028 include current signals from current sensor 2021 that senses motor current, front and rear wheel rotation speed signals obtained by rotation speed sensor 2022, and front wheel rotation speed signals obtained by air pressure sensor 2023. and rear wheel air pressure signal, vehicle speed signal acquired by vehicle speed sensor 2024, acceleration signal acquired by acceleration sensor 2025, accelerator pedal depression amount signal acquired by accelerator pedal sensor 2029, and brake pedal sensor 2026. These include a brake pedal depression amount signal, a shift lever operation signal acquired by the shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. acquired by the object detection sensor 2028.

The Information Services Department 2012 provides various devices such as car navigation systems, audio systems, speakers, televisions, and radios that provide various information such as driving information, traffic information, and entertainment information, as well as one or more devices that control these devices. It consists of an ECU. The information service unit 2012 provides various multimedia information and multimedia services to the occupants of the vehicle 1 using information acquired from an external device via the communication module 2013 and the like.

The driving support system unit 2030 includes millimeter wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g. GNSS, etc.), map information (e.g. high definition (HD) maps, autonomous vehicle (AV) maps, etc.) ), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors that prevent accidents and reduce the driver's driving burden. It consists of various devices that provide functions for the purpose and one or more ECUs that control these devices. Further, the driving support system unit 2030 transmits and receives various information via the communication module 2013, and realizes a driving support function or an automatic driving function.

The communication module 2013 can communicate with the microprocessor 2031 and the components of the vehicle 1 via the communication port. For example, the communication module 2013 communicates with the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, which are included in the vehicle 2001, through the communication port 2033. Data is transmitted and received between the axle 2009, the microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and the sensors 2021 to 2028.

The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with external devices. For example, various information is transmitted and received with an external device via wireless communication. Communication module 2013 may be located either inside or outside electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

The communication module 2013 transmits the current signal from the current sensor input to the electronic control unit 2010 to an external device via wireless communication. In addition, the communication module 2013 also receives the front wheel and rear wheel rotational speed signals acquired by the rotational speed sensor 2022, the front wheel and rear wheel air pressure signals acquired by the air pressure sensor 2023, and the vehicle speed sensor, which are input to the electronic control unit 2010. A vehicle speed signal obtained by the acceleration sensor 2024, an acceleration signal obtained by the acceleration sensor 2025, an accelerator pedal depression amount signal obtained by the accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by the brake pedal sensor 2026, and a shift lever. The shift lever operation signal acquired by the sensor 2027, the detection signal for detecting obstacles, vehicles, pedestrians, etc. acquired by the object detection sensor 2028 are also transmitted to the external device via wireless communication.

The communication module 2013 receives various information (traffic information, signal information, inter-vehicle information, etc.) transmitted from external devices, and displays it on the information service section 2012 provided in the vehicle. Communication module 2013 also stores various information received from external devices into memory 2032 that can be used by microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 controls the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, and left and right rear wheels provided in the vehicle 2001. 2008, axle 2009, sensors 2021 to 2028, etc. may be controlled.

Although the present disclosure has been described in detail above, it is clear for those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented as modifications and variations without departing from the spirit and scope of the present disclosure as determined by the claims. Therefore, the description of the present disclosure is for the purpose of illustrative explanation and is not intended to have any limiting meaning on the present disclosure.

10 Wireless communication system 20 NG-RAN
40 OAM/RIC
100 gNB
110 Wireless communication section 120 Handover processing section 130 Measurement setting section 140 Control section 200 UE
210 Wireless communication section 220 Measurement report section 230 Handover execution section 240 Control section 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive section 2003 Steering section 2004 Accelerator pedal 2005 Brake pedal 2006 shift lever 2007 left and right front wheels 2008 left and right back and right rear wheels 2009 axle 2010 axle control department 2012 information service department 2012 communication modules 2021 Current sensor 2022 rotation sensor 2023 air pressure sensor 2024 vehicle speed sensor 2025 acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 object detection Sensor 2029 Accelerator pedal sensor 2030 Driving support system section 2031 Microprocessor 2032 Memory (ROM, RAM)
2033 communication port

Claims (6)

1. a communication unit that communicates with the terminal via a wireless communication device connected to the same base station device;
   When the terminal transitions from a first cell to a second cell formed by the wireless communication device, a state in which the terminal is connected to both the first cell and the second cell using layer 1 functions is established. A wireless base station comprising a control unit to be established.
2. The control unit includes:
   transmitting unconfirmed data in a first radio link control layer on the first cell side to a packet data convergence protocol layer on the base station device side;
   The radio base station according to claim 1, wherein the packet data convergence protocol layer causes a second radio link control layer on the second cell side to transmit the data.
3. The first radio link control layer is configured to retransmit the data to the second radio link control layer after resetting the first radio link control layer, or to transmit the data to the second radio link control layer without resetting the first radio link control layer. The radio base station according to claim 2, wherein the radio base station retransmits the data to a radio link control layer, and resets the first radio link control layer after retransmitting the data.
4. a control unit that controls cell measurements including a serving cell;
   and a transmitter that transmits the measurement report,
   The control unit is a terminal that controls measurements in layer 1 of the serving cell and neighboring cells.
5. The terminal according to claim 4, wherein when a failure occurs in the layer 1, the control unit notifies the radio resource control layer of information about the failure.
6. A wireless communication system including a terminal and a wireless base station,
   The terminal is
   a control unit that performs measurement of the serving cell;
   and a transmitter that transmits the measurement report,
   The wireless base station includes a receiving unit that receives the report,
   The control unit performs layer 1 measurements of the serving cell and neighboring cells,
   The receiving unit is a wireless communication system that receives the report including measurement results of the serving cell and the neighboring cells.

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