WO2022259537A1 - Terminal and wireless base station - Google Patents

Abstract

This terminal transmits an uplink data unit via a first wireless link control entity and a second wireless link control entity, and controls the submission of the uplink data unit to the first wireless link control entity and the second wireless link control entity, on the basis of the quality of communication with a first wireless base station and/or the quality of communication with a second wireless base station.

Description

Terminal and radio base station

The present disclosure relates to terminals and wireless base stations that support dual connectivity.

The 3rd Generation Partnership Project (3GPP) has specified Long Term Evolution (LTE) and 5th generation mobile communication system (also called 5G, New Radio (NR) or Next Generation (NG)), and Beyond 5G, 5G Evolution Alternatively, the next-generation specifications called 6G are also being developed.

In Release 16 of 3GPP, uplink (UL) packet data and ULDataSplitThreshold, which is a convergence protocol layer (PDCP) flow control parameter, is defined (Non-Patent Document 1). ULDataSplitThreshold can be set as a threshold for the amount of data that can be sent to the UL on the secondary node (SN) side, and the amount of data that can be sent to the master node (MN) and SN can be controlled by the value of ULDataSplitThreshold.

　However, although the maximum amount of data that the UE transmits to the SN can be controlled by the value of ULDataSplitThreshold, the distribution of UL data to the MN and SN depends on the implementation of the UE.

Therefore, if a large amount of UL data is transmitted while the UL communication quality (which can be called radio quality) with the SN (for example, NR) is deteriorating, data may be discarded. On the other hand, if UL data is distributed between the MN and the SN even though the UL communication quality with the SN is good, the waiting time in PDCP increases, and as a result, there is a possibility that the delay time increases.

Therefore, the following disclosure is made in view of this situation, and aims to provide a terminal and a radio base station that can realize more efficient allocation of UL data to MN and SN in dual connectivity. and

One aspect of the present disclosure is the transmission unit (PDU processing unit 220) that transmits uplink data units via the first radio link control entity and the second radio link control entity, the communication quality with the first radio base station, and A control unit (control unit 240) that controls submission of the uplink data unit to the first radio link control entity and the second radio link control entity based on at least one of communication quality with the second radio base station and a terminal (UE 200).

One aspect of the present disclosure is a receiving unit (radio communication unit 110) that receives reference signals from terminals connected to a plurality of radio base stations; A radio base station (for example, eNB100A) including a control unit (control unit 150) that instructs the terminal to change the destination radio base station.

One aspect of the present disclosure is a receiving unit (control information processing unit 140) that receives a report of communication quality related to uplink from a terminal connected to a plurality of radio base stations, and based on the report, an uplink data unit and a control unit (control unit 150) for instructing the terminal to change the destination radio base station (eNB100A, for example).

FIG. 1 is an overall schematic configuration diagram of a radio communication system 10. As shown in FIG. FIG. 2 is a functional block configuration diagram of the eNB100A. FIG. 3 is a functional block configuration diagram of UE200. FIG. 4 : is a figure which shows the transmission example (part 1) of UL data at the time of dual connectivity execution of UE200. FIG. 5 : is a figure which shows the transmission example (part 2) of UL data at the time of dual connectivity execution of UE200. FIG. 6 : is a figure which shows the example (3) of transmission of UL data at the time of dual connectivity execution of UE200. FIG. 7 is a diagram illustrating an example of a transmission sequence of a buffer status report (BSR) according to operation example 4; FIG. 8 is a diagram illustrating a sequence example of changing the Primary RLC entity (Primary UL path) according to Operation Example 5. In FIG. FIG. 9 is a diagram illustrating a sequence example of changing the Primary RLC entity (Primary UL path) according to Operation Example 6. In FIG. FIG. 10 is a diagram showing an example of the hardware configuration of eNB100A, gNB100B and UE200.

Hereinafter, embodiments will be described based on the drawings. The same or similar reference numerals are given to the same functions and configurations, and the description thereof will be omitted as appropriate.

(1) Overall Schematic Configuration of Radio Communication System FIG. 1 is an overall schematic configuration diagram of a radio communication system 10 according to the present embodiment. The radio communication system 10 is a radio communication system according to Long Term Evolution (LTE) and 5G New Radio (NR). Note that LTE may be called 4G, and NR may be called 5G. Also, the radio communication system 10 may be a radio communication system conforming to a scheme called Beyond 5G, 5G Evolution, or 6G.

LTE and NR may be interpreted as radio access technology (RAT), and in this embodiment, LTE may be referred to as the first radio access technology and NR may be referred to as the second radio access technology.

The wireless communication system 10 includes an Evolved Universal Terrestrial Radio Access Network 20 (hereinafter E-UTRAN 20) and a Next Generation-Radio Access Network 30 (hereinafter NG RAN 30). The wireless communication system 10 also includes a terminal 200 (hereafter UE 200, User Equipment).

　E-UTRAN20 includes eNB100A, which is a radio base station conforming to LTE. NG RAN30 includes gNB100B, a radio base station according to 5G (NR). Note that E-UTRAN 20 and NG RAN 30 (which may be eNB100A or gNB100B) may simply be referred to as networks.

The eNB100A, gNB100B, and UE200 can support carrier aggregation (CA) using multiple component carriers (CC), and dual connectivity that simultaneously transmits component carriers between multiple NG-RAN Nodes and UEs. .

eNB100A, gNB100B and UE200 perform radio communication via radio bearers, specifically Signaling Radio Bearer (SRB) or DRB Data Radio Bearer (DRB).

In this embodiment, eNB100A configures the master node (MN) and gNB100B configures the secondary node (SN) Multi-Radio Dual Connectivity (MR-DC), specifically E-UTRA-NR Dual Connectivity ( EN-DC) or NR-E-UTRA Dual Connectivity (NE-DC) in which the gNB 100B configures the MN and the eNB 100A configures the SN. Alternatively, NR-NR Dual Connectivity (NR-DC) may be implemented in which the gNB configures the MN and SN.

In this way, the UE200 supports dual connectivity connecting to multiple wireless communication units 110 (eNB100A, gNB100B).

eNB100A is included in the master cell group (MCG) and gNB100B is included in the secondary cell group (SCG). In other words, gNB100B is an SN included in the SCG.

The eNB100A and gNB100B may be called radio base stations or network devices.

Also, in the radio communication system 10, parameters may be introduced that control UL data that the UE 200 transmits to the eNB 100A (E-UTRAN 20) and gNB 100B (NG RAN 30) in dual connectivity.

Specifically, the threshold of UL data that the UE 200 can transmit to the E-UTRAN 20 (which may be interpreted as the primary side (or secondary side)) or the NG RAN 30 (which may be interpreted as the secondary side (or primary side)) A parameter (ULDataSplitThreshold) indicating (upper limit) may be introduced.

　ULDataSplitThreshold is specified in 3GPP TS38.323 and TS38.331. ULDataSplitThreshold may be interpreted as a Packet Data Convergence Protocol Layer (PDCP) flow control parameter. ULDataSplitThreshold may define the threshold of the amount of data that can be transmitted to the UL on the SN side, but may also define the threshold of the amount of data that can be transmitted to the UL on the MN side.

　ULDataSplitThreshold may be defined by the number of bytes (eg, 0 bytes, 100 bytes, 200 bytes, etc.), but may also be defined by the number of protocol data units (PDUs), throughput, etc.

(2) Functional Block Configuration of Radio Communication System Next, the functional block configuration of the radio communication system 10 will be described. Specifically, functional block configurations of eNB 100A and UE 200 will be described.

(2.1) eNB100A
FIG. 2 is a functional block configuration diagram of the eNB100A. As shown in FIG. 2, the eNB 100A includes a wireless communication unit 110, a NW connection unit 120, a PDU processing unit 130, a control information processing unit 140 and a control unit 150. The gNB100B may also have the same functions as the eNB100A, although the gNB100B is different in that it supports NR.

The radio communication unit 110 transmits downlink signals (DL signals) according to LTE. Radio communication section 110 also receives an uplink signal (UL signal) according to LTE.

The radio communication unit 110 can receive a reference signal (RS) from the UE200. Specifically, radio communication section 110 can receive SRS (Sounding reference signal) and DMRS (Demodulation reference signal), which are UL reference signals transmitted from UE 200 .

A sounding reference signal (SRS) is a UL reference signal for measuring UL channel quality, reception timing, etc. on the radio base station side. A demodulation reference signal (DMRS) is a known reference signal between a terminal-specific base station and a terminal for estimating a fading channel used for data demodulation.

The NW connection unit 120 provides interfaces required for connection with other RAN nodes and core network nodes that make up the network. In particular, in this embodiment, the NW connection unit 120 can provide connection interfaces (X2/Xn, etc.) with the gNB 100B via the E-UTRAN 20 and NG RAN 30. Also, data (mainly user data) transmitted and received between the UE 200 and the network may be relayed via the interface. Specifically, a PDU (data PDU, control PDU) storing user data (or control data) may be relayed via the interface. A PDU may be broadly interpreted as an IP (Internet Protocol) packet or simply a packet.

The PDU processing unit 130 executes processing related to assembly and disassembly of PDUs. Specifically, the PDU processing unit 130 processes PDU/SDU in multiple layers (medium access control layer (MAC), radio link control layer (RLC), packet data convergence protocol layer (PDCP), etc.). (service data unit) assembly/disassembly, etc.

The control information processing unit 140 executes processing related to various control signals transmitted and received by the eNB 100A and processing related to various reference signals transmitted and received by the eNB 100A.

Specifically, the control information processing unit 140 receives various control signals transmitted from the UE 200 via a predetermined control channel, for example, radio resource control layer (RRC) control signals. Also, the control information processing unit 140 transmits various control signals to the UE 200 via a predetermined control channel.

The control information processing unit 140 may execute various processes in the radio resource control layer (RRC). Specifically, control information processing section 140 can transmit RRC Reconfiguration to UE 200 . Also, control information processing section 140 can receive RRC Reconfiguration Complete, which is a response to RRC Reconfiguration, from UE 200 .

In addition, in this embodiment, the eNB 100A supports LTE, but in this case, the name of the RRC message may be RRC Connection Reconfiguration or RRC Connection Reconfiguration Complete.

Also, the control information processing unit 140 may receive a communication quality report related to UL from the UE 200 . In this embodiment, the control information processing unit 140 may constitute a receiving unit that receives communication quality reports. Specifically, the control information processing unit 140 may report UL RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality) or SINR (Signal-to-Interference plus Noise power Ratio).

RSRP (Reference Signal Received Power) is the received level of the reference signal measured by UE200, and RSRQ (Reference Signal Received Quality) is the received quality of the reference signal measured by UE200 (cell-specific reference signal power and , which may be interpreted as the ratio of the total power within the receive bandwidth). That is, the reported communication quality (which may be referred to as radio quality) is not necessarily measured at the UL receiver side, but may be estimated based on measurements at the downlink (DL) side. .

Also, communication quality may be measured at Layer 1 (L1) or Layer 3 (L3). Layer 1 may be interpreted to include lower layers such as the physical layer. Layer 3 is a higher layer than layer 1 . The upper layer may include at least one of RLC, PDCP, and RRC, and MAC may be located between the lower layer and the upper layer.

The layer on which UL-related communication quality reporting is performed is not particularly limited, but may be included in UE Assistance Information (see 3GPP TS38.331) and transmitted from UE 200, for example.

The control unit 150 controls each functional block that configures the eNB 100A. In particular, in the present embodiment, the control unit 150 executes control regarding the transmission destination of UL data transmitted from the UE200.

Specifically, the control unit 150 may control the destination of the UL-direction PDU (which may be called an uplink data unit) transmitted from the UE 200 . When the communication quality of the reference signal (SRS or DMRS) received from UE 200 is below a specific threshold, control section 150 can instruct UE 200 to change the radio base station to which the PDU is transmitted.

The control unit 150 can also instruct the UE 200 to change the PDU transmission destination radio base station based on the UL-related communication quality report received from the UE 200 .

For example, when the communication quality is below the threshold set in the network, the control unit 150 changes the transmission destination of the PDU in the UL direction from gNB100B to eNB100A (or vice versa) for the UE200 executing DC. may be instructed to do so.

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

In addition, data channels include PDSCH (Physical Downlink Shared Channel) and PUSCH (Physical Uplink Shared Channel).

Reference signals include demodulation reference signal (DMRS), sounding reference signal (SRS), phase tracking reference signal (PTRS), and channel state information-reference signal (CSI-RS). Channels and reference signals are included. Data may also refer to data transmitted over a data channel.

(2.2) UE200
FIG. 3 is a functional block configuration diagram of UE200. As shown in FIG. 3, the UE 200 includes a radio communication section 210, a PDU processing section 220, a quality measurement section 230 and a control section 240.

The radio communication unit 210 transmits an uplink signal (UL signal) according to LTE or NR. Also, the radio communication unit 210 receives a downlink signal (DL signal) according to LTE. That is, UE200 can access eNB100A (E-UTRAN20) and gNB100B (NG RAN30), and can support dual connectivity (specifically, EN-DC).

The PDU processing unit 220 executes processing related to assembly and disassembly of PDUs. Specifically, the PDU processing unit 220 assembles/disassembles PDU/SDU in MAC, RLC, PDCP, and the like.

The PDU processing unit 220 can transmit PDUs (uplink data units) in the UL direction via multiple radio link control entities (RLC entities). Specifically, the PDU processing unit 220 performs UL direction PDU processing via a radio link control entity for eNB 100A (first radio link control entity) and a radio link control entity for gNB 100B (second radio link control entity). can be sent. In the present embodiment, the PDU processing unit 220 may constitute a transmitting unit for transmitting upstream data units.

A first radio link control entity may be called a Primary RLC entity. Also, the secondary radio link control entity may be called a secondary RLC entity. PDCP data (PDU) located above RLC may be submitted to any RLC entity.

The quality measurement unit 230 measures the communication quality (radio quality) of radio signals transmitted and received by the UE200. Specifically, quality measuring section 230 can measure the RSRP and RSRQ of the reference signal received by UE 200 or the SINR of the radio signal in the frequency band received by UE 200 . Also, the quality measurement unit 230 may report the communication quality measurement result to the network. As described above, the report may use, for example, UE Assistance Information.

In addition, the quality measurement unit 230 may report to the network a report indicating the status of the buffer provided in the UE 200 (the amount of UL data retained, etc.), specifically, a buffer status report (BSR).

Furthermore, the quality measurement unit 230 may estimate the distance to the radio base station based on information on transmission power (PHR: power headroom) or timing information (TA: Timing Advance). Specifically, quality measurement section 230 determines that the distance is short if the PHR (the difference between the estimated value of the required transmission power of PUSCH and the maximum transmission power) is large, and that the distance is long if the PHR is small. You can Also, the quality measuring section 230 may determine that the distance is longer as the value of TA is larger.

The control unit 240 controls each functional block that configures the UE200. In particular, in this embodiment, the control unit 240 executes control related to transmission of PDUs (uplink data units) in the UL direction when dual connectivity (DC) is executed.

Specifically, based on at least one of the communication quality with eNB 100A (first radio base station) and the communication quality with gNB 100B (second radio base station), the control unit 240 controls the first radio link control entity (Primary RLC entity) and the submission of PDUs to the secondary radio link control entity (Secondary RLC entity).

More specifically, the control unit 240 may perform control so that PDUs are preferentially submitted to RLC entities with good communication quality. In other words, control may be performed so that more PDUs are submitted to RLC entities with good communication quality.

In addition, when the amount of PDUs in the UL direction exceeds, for example, the UL data threshold (ULDataSplitThreshold) with gNB100B (second radio base station), eNB100A (first radio base station and gNB100B) UL direction PDUs may be indicated to MAC entities associated with RLC entities for radio base stations with good communication quality.

Specifically, the control unit 240 converts PDCP data (PDU, which may be referred to as data volume) to the MAC entity associated with the Primary RLC entity or the MAC entity associated with the Secondary RLC entity. can be presented to any This makes it possible to preferentially present PDCP PDUs to MAC entities associated with RLC entities with good communication quality.

Also, the control unit 240 may preferentially submit UL-direction PDUs (uplink data units) with high required quality of service (QoS) to the RLC entity. For example, the control unit 240 may determine the QoS required for the PDU based on the QoS level of the data flow in the UL direction or the network slice information.

Also, the control unit 240 can control transmission of a buffer status report (BSR) to a radio base station with good communication quality among eNB100A and gNB100B. Specifically, control section 240 can cause quality measuring section 230 to transmit BSR to a radio base station with good communication quality.

(3) Operation of Radio Communication System Next, the operation of the radio communication system 10 will be described. Specifically, operations related to throughput improvement in the UL direction when UE 200 executes dual connectivity will be described.

(3.1) Premise FIG. 4 shows an example (part 1) of transmission of UL data when the UE 200 performs dual connectivity. As shown in FIG. 4, UE200 can transmit UL data (PDU) toward NR (gNB100B), but if NR communication quality (for example, radio link quality between UE200 and gNB100B) is poor (UE200 NR cell edge), gNB 100B cannot receive UL data normally, and an event may occur in which UL data is retained or discarded.

As described above, by lowering the value of ULDataSplitThreshold, which is a type of UL PDCP flow control parameter, UL data can be flowed to the LTE (eNB100A) side, and UL data retention (may be called packet clogging, etc.) There is a certain effect in eliminating such as.

However, there are still the following problems. Specifically, how UE200 distributes UL data to LTE/NR depends on the implementation of UE200. Therefore, when a large amount of UL data is sent to NR, UL data retention occurs.

Also, when the communication quality of NR is good (such as when the UE 200 is located in the center of the NR cell), queuing in the PDCP layer can be reduced by sending UL data only to NR where higher throughput can be expected. In such a case, if UL data is also sent to LTE, there is a concern that the delay will increase.

Thus, when the UE 200 is located in a place (area) where NR communication quality is poor, UL data retention is likely to occur.

FIG. 5 shows an example (part 2) of UL data transmission when the UE 200 executes dual connectivity. As shown in Figure 5, even if the value of ULDataSplitThreshold is set low, UL PDCP flow control in UE200 does not consider UL quality, so UL data may flow to NR with poor quality, and UL data Stagnation can occur.

FIG. 6 shows an example (part 3) of UL data transmission when the UE 200 executes dual connectivity. As shown in FIG. 6, even when the NR communication quality recovers (for example, the UE 200 moves to the center of the NR cell), the UE 200 may flow the UL data to the LTE side, thereby assembling the PDU in the PDCP layer. , resulting in an increase in delay.

In the following, an operation example that can solve such problems, achieve more efficient allocation of UL data to MN and SN when executing dual connectivity of UE 200, and improve throughput in the UL direction will be described.

(3.2) Operation example (3.2.1) Operation example 1
In this operation example, the UE 200 determines the communication quality of the Primary RLC entity or the Secondary RLC entity (hereinafter, abbreviated to quality as appropriate) in the UL PDCP data transfer transmit operation, and determines the UL direction PDU, specifically, PDCP The data PDUs may be sent (submitted) to the RLC entity with better quality.

In this case, the UE 200 refers to the DL layer 1 (L1) or layer 3 (L3) quality measurement result in the cell (primary cell (PCell) or secondary cell (SCell)), and estimates the UL quality in the cell. You can

Note that, as described above, the quality may be at least one of RSRP, RSRQ, or SINR. Alternatively, the UE 200 may estimate the distance to the radio base station based on the PHR (power headroom) or TA (timing advance) value, and estimate the UL quality according to the estimated distance.

Also, the UL quality information estimated in this way may be provided from the PHY or RRC layer of the UE 200 to the PDCP layer as assistance information.

The PHR is the difference between the estimated PUSCH transmission power requirement and the maximum transmission power. If the PHR is large, it may be determined that the distance is short, and if the PHR is small, it may be determined that the distance is long. Since TA increases in conjunction with the distance to the radio base station, it may be determined that the greater the value of TA, the longer the distance.

Also, the UE 200 may set a threshold for UL quality (the UE 200 itself may hold the threshold). The UE 200 may determine that the UL quality of the cell (RLC entity) is good when the UL quality exceeds the threshold.

　UE 200 may transmit a PDCP data PDU to the RLC entity estimated to have good UL quality. Also, when the UL quality of both the NR cell and the LTE cell (RLC entity) is good, the UE 200 may preferentially transmit (submit) the PDCP data PDU to the NR cell (RLC entity).

　3GPP TS 38.323 5.2.1 describes ULDataSplitThreshold as follows.

- if the total amount of PDCP data volume and RLC data volume pending for initial transmission (as specified in TS 38.322 [5]) in the primary RLC entity and the split secondary RLC entity is equal to or larger than ul-DataSplitThreshold:
- submit the PDCP PDU to either the primary RLC entity or the split secondary RLC entity;
In this operation example, as described above, a PDCP data PDU (PDCP data volume) is submitted to the RLC entity whose quality is estimated to be good.

In 3GPP Release 16, up to four RLC entities can be set, and three secondary RLC entities can be set. It may be taken to refer to an entity, i.e. an RLC entity that is responsible for Split bearer operations in one or more Secondary RLC entities.

(3.2.2) Operation example 2
In this operation example, UE 200 preferentially presents PDCP data PDU (PDCP data volume) to a MAC entity associated with an RLC entity (which may be interpreted as a cell) with good UL quality. You may (indicate).

Specifically, when calculating the PDCP data volume, the UE 200 calculates the Primary RLC entity and (Split) Secondary RLC entity if the total amount value of the PDCP data volume and RLC data volume pending for initial transmission is greater than ULDataSplitThreshold. Among them, the PDCP data volume may be indicated for the MAC entity associated with the RLC entity with good quality.

On the other hand, when the quality of both the Primary RLC entity and (Split) Secondary RLC entity is good, the UE 200 gives priority to the MAC entity associated with the RLC entity on the NR side (higher throughput can be expected) You may indicate the PDCP data volume.

Specifically, the UE 200 may indicate all PDCP data volumes to the MAC entity associated with the NR-side RLC entity, or indicate to the MAC entity associated with the NR-side RLC entity the LTE-side RLC entity. MAY indicate more PDCP data volumes than MAC entities associated with it.

Also, the UE 200 may indicate the PDCP data volume as "0" for MAC entities associated with RLC entities with poor quality (below the threshold).

　3GPP TS 38.323 Chapter 5.6 describes the PDCP data volume and MAC entity as follows.

- indicate the PDCP data volume to both the MAC entity associated with the primary RLC entity and the MAC entity associated with the split secondary RLC entity;
In this operation example, as described above, the PDCP data volume may be preferentially indicated to MAC entities associated with RLC entities (cells) with good quality.

(3.2.3) Operation example 3
In this operation example, the UE 200 may determine the RLC entity to which the PDCP data PDU is transmitted (submitted) based on the quality of service (QoS) of the UL data.

Specifically, the UE 200 gives priority to PDCP data PDUs assigned to radio bearers with high QoS requirements, taking into consideration the QoS of the UL data flow or network slice (which may be simply referred to as slice) information. may be (first) submitted to the RLC entity.

A network slice is a platform that provides functions and performance adapted to the characteristics of the services provided (e.g., enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low Latency Communications (URLLC), etc.). The required QoS (delay, etc.) can be different. QoS information may be obtained from Service Data Adaptation Protocol (SDAP) entities.

Also, the UE 200 may first submit PDCP data PDUs with high QoS requirements to RLC entities with good quality.

(3.2.4) Operation example 4
In this operation example, the UE 200 may determine the RLC entity to which the buffer status report (BSR) is to be transmitted (submitted) based on the quality (UL quality) of the RLC entity.

FIG. 7 shows a transmission sequence example of a buffer status report (BSR) according to operation example 4. As shown in FIG. 7, the UE 200 may estimate the UL quality according to the quality estimation method of the operation example described above when transmitting the BSR from the MAC entity to the network (step 1).

The UE 200 may select any RLC entity with good quality and transmit the BSR via that RLC entity (steps 2 and 3).

Note that a threshold for UL quality determination that is applied when the UE 200 selects an RLC entity may be set. Note that the threshold may be preset in the UE 200, or may be notified by signaling from the network.

When the UL quality of both the primary RLC entity and the secondary RLC entity, that is, both the NR cell and the LTE cell exceeds the threshold and the quality is good, the UE 200 may preferentially transmit the BSR to the NR cell.

Also, the estimated UL quality information may be provided from the PHY or RRC layer of the UE 200 to the MAC layer as assistance information.

(3.2.5) Operation example 5
In this operation example, the network may change the Primary RLC entity (Primary UL path) used for transmitting UL data based on the quality of the reference signal (RS) from UE200.

FIG. 8 shows a sequence example of changing the Primary RLC entity (Primary UL path) according to Operation Example 5. As shown in FIG. 8, UE200 transmits SRS and/or DMRS to the network (eNB100A, gNB100B) (step 1).

The network (here, the eNB 100A) decides to change the Primary RLC entity (Primary UL path) used for UL data transmission when the quality of the RS falls below the threshold (step 2). Here, it is assumed that the NR side is changed to the LTE side.

The network transmits RRC Reconfiguration including the change instruction to the UE 200 (step 3).

The UE 200 switches the Primary RLC entity (Primary UL path) used for UL data transmission from NR to LTE based on the change instruction included in RRC Reconfiguration (step 4).

(3.2.6) Operation example 6
In this operation example, the network may change the Primary RLC entity (Primary UL path) used for UL data transmission based on the UL quality report from the UE 200 .

FIG. 9 shows a sequence example of changing the Primary RLC entity (Primary UL path) according to Operation Example 6. As shown in FIG. 9, UE200 transmits UE Assistance Information to the network (here, eNB100A) (step 1).

　UE Assistance Information may include information indicating that the UL quality on the Primary RLC entity side is poor. Note that, as described above, the UE 200 may estimate the UL quality from the DL quality.

The network (here, the eNB 100A) decides to change the Primary RLC entity (Primary UL path) used for UL data transmission based on the contents of the UE Assistance Information (step 2). Here, it is assumed that the NR side is changed to the LTE side.

The network transmits RRC Reconfiguration including the change instruction to the UE 200 (step 3).

The UE 200 switches the Primary RLC entity (Primary UL path) used for UL data transmission from NR to LTE based on the change instruction included in RRC Reconfiguration (step 4).

(4) Functions and Effects According to the above-described embodiment, the following functions and effects are obtained. Specifically, the UE 200 and the network can control the RLC entity to which PDCP data PDUs in the UL direction are transmitted (submitted) based on the UL quality. The UE 200 can also indicate PDCP data volume for MAC entities associated with RLC entities with good quality.

Therefore, the UE200 can control the flow of UL data according to the UL quality, and more reliably avoid UL data retention (packet clogging) when located in a location (area) with poor NR quality. obtain.

Also, for example, ULDataSplitThreshold is set to a low value, and even if the UL quality on the NR side recovers, UL data continues to be transmitted to the LTE side, resulting in an increase in delay due to waiting in the PDCP layer between NR and LTE. can also be avoided.

That is, according to this embodiment, more efficient distribution of UL data to MN and SN (for example, LTE and NR sides) can be realized in dual connectivity.

In this embodiment, the UE 200 may preferentially submit to the RLC entity UL-direction PDCP data PDUs with higher required QoS. Also, the UE 200 can transmit a buffer status report (BSR) to a radio base station with good communication quality. Therefore, more efficient allocation of UL data to MN and SN can be achieved.

In this embodiment, the network can instruct UE200 to change the transmission destination of PDCP data PDU in the UL direction based on the quality of the reference signal (RS) received from UE200 or the UL quality reported from UE200. Therefore, it is possible to efficiently distribute UL data to MN and SN according to UL quality.

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

For example, in the above-described embodiment, the EN-DC in which the MN is the eNB and the SN is the gNB was described as an example, but other DCs may be used as described above. Specifically, NR-DC in which MN is gNB and SN is gNB, or NE-DC in which MN is gNB and SN is eNB may be used.

In the above description, configure, activate, update, indicate, enable, specify, and select may be read interchangeably. Similarly, link, associate, correspond, and map may be read interchangeably to allocate, assign, monitor. , map, may also be read interchangeably.

Furthermore, specific, dedicated, UE-specific, and UE-specific may be read interchangeably. Similarly, common, shared, group-common, UE common, and UE shared may be read interchangeably.

Also, the block configuration diagrams (FIGS. 2 and 3) used to describe the above-described embodiment show blocks in units of functions. These functional blocks (components) are realized by any combination of at least one of hardware and software. Also, the method of implementing each functional block is not particularly limited. That is, each functional block may be implemented using one device physically or logically coupled, or directly or indirectly using two or more physically or logically separate devices (e.g. , wired, wireless, etc.) and may be implemented using these multiple devices. A functional block may be implemented by combining software in the one device or the plurality of devices.

Functions include judging, determining, determining, calculating, calculating, processing, deriving, investigating, searching, checking, receiving, transmitting, outputting, accessing, resolving, selecting, choosing, establishing, comparing, assuming, expecting, assuming, Broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc. can't For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. In either case, as described above, the implementation method is not particularly limited.

Furthermore, the above-described eNB100A, gNB100B and UE200 (applicable device) may function as a computer that performs processing of the wireless communication method of the present disclosure. FIG. 10 is a diagram showing an example of the hardware configuration of the device. As shown in FIG. 10, the device may be configured as a computing device including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, bus 1007, and the like.

In the following explanation, the term "apparatus" can be read as a circuit, device, unit, or the like. The hardware configuration of the device may be configured to include one or more of each device shown in the figure, or may be configured without some of the devices.

Each functional block of the device (see Fig. 2.3) is realized by any hardware element of the computer device or a combination of the hardware elements.

In addition, each function of the device is implemented by causing the processor 1001 to perform calculations, controlling communication by the communication device 1004, and controlling the It is realized by controlling at least one of data reading and writing in 1002 and storage 1003 .

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

Also, 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 them. 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 an electric communication line.

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

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

The communication device 1004 is hardware (transmitting/receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also called a network device, a network controller, a network card, a communication module, or the like.

The communication device 1004 includes a high-frequency switch, duplexer, filter, frequency synthesizer, etc., for realizing at least one of frequency division duplex (FDD) and time division duplex (TDD). may consist of

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

Also, 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 between devices.

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

In addition, notification of information is not limited to the aspects/embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may include physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB), other signals, or combinations thereof, and RRC signaling may also be referred to as RRC messages, e.g., RRC Connection Setup ) message, RRC Connection Reconfiguration message, or the like.

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®), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth®, other suitable systems, and/or next-generation systems enhanced therefrom. may be applied to Also, a plurality of systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A and 5G).

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

A specific operation that is performed by a base station in the present disclosure may be performed by its upper node in some cases. In a network consisting of one or more network nodes with a base station, various operations performed for communication with a terminal may be performed by the base station and other network nodes other than the base station (e.g. MME or S-GW, etc., but not limited to). Although the case where there is one network node other than the base station is exemplified above, it may be a combination of a plurality of other network nodes (for example, MME and S-GW).

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

Input/output information may be stored in a specific location (for example, memory) or managed using a management table. Input and output information may be overwritten, updated, or appended. The output information may be deleted. The entered information may be transmitted to other devices.

The determination may be made by a value represented by one bit (0 or 1), by a true/false value (Boolean: true or false), or by numerical comparison (for example, a predetermined value).

Each aspect/embodiment described in the present disclosure may be used alone, may be used in combination, or may be used by switching along with execution. In addition, the notification of predetermined information (for example, notification of “being X”) is not limited to being performed explicitly, but may be performed implicitly (for example, not notifying the predetermined information). good too.

Software, whether referred to as software, firmware, middleware, microcode, hardware description language or otherwise, includes instructions, instruction sets, code, code segments, program code, programs, subprograms, and software modules. , applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, and the like.

In addition, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, 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 access websites, Wired and/or wireless technologies are included within the definition of transmission medium when sent from a server or other remote source.

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 these. may be represented by a combination of

The terms explained in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, the channel and/or symbols may be signaling. A signal may also be a message. A component carrier (CC) may also be called a carrier frequency, a cell, a frequency carrier, or the like.

The terms "system" and "network" used in this disclosure are used interchangeably.

In addition, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values from a predetermined value, or may be expressed using other corresponding information. may be represented. For example, radio resources may be indexed.

The names used for the parameters described above are not restrictive names in any respect. Further, the formulas, etc., using these parameters may differ from those expressly 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 designations assigned to these various channels and information elements are in no way restrictive designations. is not.

In the present disclosure, "base station (BS)", "radio base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", " "access point", "transmission point", "reception point", "transmission/reception point", "cell", "sector", "cell group", " Terms such as "carrier", "component carrier" may be used interchangeably. A base station may also be referred to by terms such as macrocell, small cell, femtocell, picocell, and the like.

A base station can accommodate one or more (eg, three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of the base station can be partitioned into multiple smaller areas, each smaller area corresponding to a base station subsystem (e.g., a small indoor base station (Remote Radio)). Head: RRH) can also provide communication services.

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

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

A mobile station is defined by those 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 called a terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term.

At least one of the base station and mobile station may be called a transmitting device, a receiving device, a communication device, or the like. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, or the like. The mobile body may be a vehicle (e.g., car, airplane, etc.), an unmanned mobile body (e.g., drone, 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 mobile station may be an Internet of Things (IoT) device such as a sensor.

Also, 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, 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. Also, 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 read as side channels.

Similarly, mobile stations in the present disclosure may be read as base stations. In this case, the base station may have the functions that the mobile station has.
A radio frame may consist of one or more frames in the time domain. Each frame or frames in the time domain may be referred to as a subframe. A subframe may also consist of one or more slots in the time domain. A subframe may be a fixed time length (eg, 1 ms) independent of numerology.

A numerology may be a communication parameter that applies to the transmission and/or reception of a signal or channel. Numerology, for example, subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, transmission and reception specific filtering operations performed by the receiver in the frequency domain, specific windowing operations performed by the transceiver in the time domain, and/or the like.

A slot may consist 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 contain multiple mini-slots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be referred to as a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) that is transmitted in time units larger than a minislot 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. Radio frames, subframes, slots, minislots and symbols may be referred to by other corresponding designations.

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

Here, TTI refers to, for example, the minimum scheduling time unit in wireless communication. For example, in the 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 transmission time unit for channel-encoded data packets (transport blocks), code blocks, codewords, etc., or may be a processing unit for scheduling, link adaptation, etc. Note that when a TTI is given, the time interval (for example, the number of symbols) in which transport blocks, code blocks, codewords, etc. are actually mapped may be shorter than the TTI.

If 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 scheduling time unit. Also, the number of slots (the number of mini-slots) constituting 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 a regular TTI may also be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a minislot, a subslot, a slot, and so on.

In addition, long TTI (for example, normal TTI, subframe, etc.) may be read as TTI having a time length exceeding 1 ms, and short TTI (for example, shortened TTI, etc.) is less than the TTI length of long TTI and 1 ms. A TTI having a TTI length greater than or equal to this value may be read as a replacement.

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

Also, the time domain of an RB may include one or more symbols and may be 1 slot, 1 minislot, 1 subframe, or 1 TTI long. One TTI, one subframe, etc. may each consist of one or more resource blocks.

One or more RBs are physical resource blocks (Physical RB: PRB), sub-carrier groups (SCG), resource element groups (REG), PRB pairs, RB pairs, etc. may be called.

In addition, a resource block may be composed of one or more resource elements (Resource Element: RE). For example, 1 RE may be a radio resource region of 1 subcarrier and 1 symbol.

A Bandwidth Part (BWP) (which may also be called a Bandwidth Part) represents a subset of contiguous common resource blocks (RBs) for a neumerology in a carrier. good. Here, the common RB may be identified by an RB index based on the 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 in one carrier for a 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 read as "BWP".

The structures such as radio frames, subframes, slots, minislots and symbols described above are only 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 Configurations such as the number of subcarriers and the number of symbols in a TTI, symbol length, cyclic prefix (CP) length, etc. can be varied.

The terms "connected," "coupled," or any variation thereof mean any direct or indirect connection or coupling between two or more elements, It can include the presence of one or more intermediate elements between two elements being "connected" or "coupled." Couplings or connections between elements may be physical, logical, or a combination thereof. For example, "connection" may be read as "access". As used in this disclosure, two elements are defined using at least one of one or more wires, cables and printed electrical connections and, as some non-limiting and non-exhaustive examples, in the radio frequency domain. , electromagnetic energy having wavelengths in the microwave and light (both visible and invisible) regions, and the like.

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

The term "based on" as used in this disclosure does not mean "based only on" unless otherwise specified. In other words, the phrase "based on" means both "based only on" and "based at least on."

"Means" in the configuration of each device described above may be replaced with "unit", "circuit", "device", or the like.

Any reference to elements using the "first," "second," etc. designations used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, references to first and second elements do 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 are inclusive, as is the term "comprising." is intended. Furthermore, the term "or" as used in this disclosure is not intended to be an exclusive OR.

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

The terms "determining" and "determining" used in this disclosure may encompass a wide variety of actions. "Judgement" and "determination" are, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (eg, lookup in a table, database, or other data structure), ascertaining as "judged" or "determined", and the like. Also, "judgment" and "determination" are used for receiving (e.g., receiving information), transmitting (e.g., transmitting information), input, output, access (accessing) (for example, accessing data in memory) may include deeming that a "judgment" or "decision" has been made. In addition, "judgment" and "decision" are considered to be "judgment" and "decision" by resolving, selecting, choosing, establishing, comparing, etc. can contain. In other words, "judgment" and "decision" can include considering that some action is "judgment" and "decision". Also, "judgment (decision)" may be read as "assuming", "expecting", "considering", or the like.

In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean that "A and B are different from C". Terms such as "separate," "coupled," etc. may also be interpreted in the same manner as "different."

Although the present disclosure has been described in detail above, it is clear to 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 practiced with modifications and variations without departing from the spirit and scope of the present disclosure as defined by the claims. Accordingly, the description of the present disclosure is for illustrative purposes and is not meant to be limiting in any way.

10 Radio communication system 20 E-UTRAN
30NG RAN
100A eNB
100B gNB
110 wireless communication unit 120 NW connection unit 130 PDU processing unit 140 control information processing unit 150 control unit 200 UE
210 wireless communication unit 220 PDU processing unit 230 quality measurement unit 240 control unit 1001 processor 1002 memory 1003 storage 1004 communication device 1005 input device 1006 output device 1007 bus

Claims (6)

1. a transmitter for transmitting uplink data units via the first radio link control entity and the second radio link control entity;
   transmitting the uplink data unit to the first radio link control entity and the second radio link control entity based on at least one of communication quality with the first radio base station and communication quality with the second radio base station; and a control unit for controlling submission.
2. When the amount of the uplink data unit exceeds a threshold value for uplink data with the second radio base station, the control unit determines which of the first radio base station and the second radio base station has better communication quality. The terminal according to claim 1, wherein the uplink data unit is presented to a medium access control layer entity associated with a radio link control entity intended for a radio base station.
3. 　The terminal according to claim 1, wherein the control unit preferentially submits the uplink data unit for which the required service quality is high.
4. The terminal according to claim 1, wherein the control unit controls transmission of the buffer status report to a radio base station with good communication quality among the first radio base station and the second radio base station.
5. a receiving unit that receives reference signals from terminals connected to a plurality of wireless base stations;
   and a control unit that instructs the terminal to change the radio base station to which the uplink data unit is transmitted when the communication quality of the reference signal is below a specific threshold.
6. a receiving unit that receives uplink-related communication quality reports from terminals connected to a plurality of radio base stations;
   and a control unit that instructs the terminal to change the destination radio base station of the uplink data unit based on the report.

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