Terminal, base station, and communication control method

Abstract

A terminal according to the present invention comprises: a reception unit that receives, from a base station, change information which indicates a change in packet data convergence protocol sequence number (PDCP SN) length from a currently applied PDCP SN length; and a control unit that applies the change in PDCP SN length without re-establishment of a PDCP, in response to reception of the change information by the reception unit.

Description

Terminal, base station and communication control method

[0001] The present disclosure relates to a terminal, a base station, and a communication control method.

[0002] The 3rd Generation Partnership Project (3GPP: registered trademark) is developing specifications for the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also developing specifications for the next generation, known as Beyond 5G, 5G Evolution, or 6G.

[0003] 5G Evolution and the next-generation 6G communications technology are expected to further enhance the 5G characteristics of "high speed and large capacity," "low latency," and "multiple connections," while also expanding the technology into new areas such as "expanding communication areas to the sky, sea, and space," "realizing ultra-low power consumption and low-cost communications," and "ultra-reliable communications for industrial applications."

[0004] In the current specifications of wireless communication systems, a Packet Data Convergence Protocol (PDCP) layer is defined above a Radio Link Control (RLC) layer (see Non-Patent Document 1).

[0005] When PDCP is reestablished, such as when a terminal performs a handover to another cell or reconnects to a cell, the terminal transmits a PDCP status report to the base station.

[0006] The purpose of the PDCP status report is to report the reception status at the PDCP level of the terminal to the base station, thereby avoiding duplicate transmission of Protocol Data Units (PDUs) at the PDCP level, i.e., PDCP PDUs, after terminal handover or reconnection.

[0007] 3GPP TS 38.323 V17.5.0 (2023-06)

[0008] In future wireless communication systems, data traffic is expected to increase compared to current wireless communication systems due to the above-mentioned technological advancements. Accordingly, it is expected that the length of the PDCP Sequence Number (SN) will be extended (e.g., to 32 bits) to manage PDCP PDUs. However, no specification has been made regarding the operation related to control when the PDCP SN length is extended. If such operation is not properly specified, it may lead to degradation of the wireless communication system.

[0009] One aspect of the present disclosure provides a terminal, a base station, and a communication control method that can prevent or suppress degradation of a wireless communication system when the length of the PDCP SN is extended.

[0010] A terminal according to one embodiment of the present disclosure includes: a receiving unit that receives, from a base station, change information indicating a change in Packet Data Convergence Protocol Sequence Number (PDCP SN) length from a currently applied PDCP SN length; and a control unit that, in response to the receiving unit receiving the change information, applies the PDCP SN length change without re-establishing PDCP.

[0011] FIG. 1 is a diagram showing an example of a wireless communication system according to an embodiment. FIG. 1 is a diagram showing example configurations of radio frames, subframes, and slots used in the wireless communication system. FIG. 2 is a diagram showing an example of an NR protocol stack. FIG. 2 is a diagram showing a PDCP control PDU format for a PDCP status report. FIG. 3 is a diagram explaining a D / C field. FIG. 4 is a diagram explaining a PDU Type field. FIG. 4 is a diagram showing an example configuration of a COUNT value. FIG. 5 is a diagram showing an example configuration of a PDCP control PDU format for a PDCP status report according to an embodiment. FIG. 5 is a diagram showing an example configuration of a COUNT value according to an embodiment. FIG. 6 is a diagram showing an example configuration of a PDCP control PDU format for PDCP SN length change according to an embodiment. FIG. 7 is a diagram showing an example configuration of a PDCP control PDU format for PDCP SN length change according to an embodiment. FIG. 8 is a diagram showing an example configuration of a PDCP control PDU format for PDCP SN length change according to an embodiment. FIG. 9 is a diagram showing an example configuration of a PDCP control PDU format for PDCP SN length change according to an embodiment. FIG. 10 is a diagram showing an example configuration of a PDCP control PDU format for PDCP SN length change according to an embodiment. It is a block diagram showing an example of the configuration of a terminal according to an embodiment.It is a diagram showing an example of the hardware configuration of a base station and a terminal according to an embodiment.It is a diagram showing an example of the configuration of a vehicle.

[0012] Hereinafter, an embodiment according to one aspect of the present disclosure will be described with reference to the drawings.

[0013] <Wireless System Configuration> Fig. 1 is a diagram showing an example of a wireless communication system 10 according to an embodiment. The wireless communication system 10 is a wireless communication system conforming to New Radio (NR) and includes a Next Generation-Radio Access Network (hereinafter referred to as NG-RAN 20 and a terminal 200). The wireless communication system 10 may be a wireless communication system conforming to a scheme called 5G, Beyond 5G, 5G Evolution, or 6G. The terminal is also referred to as User Equipment (UE).

[0014] The NG-RAN 20 includes a base station 100. The base station 100 may be, for example, a gNB or an ng-eNB. The NG-RAN 20 is connected to a core network (e.g., 5GC, not shown) conforming to NR. The NG-RAN 20 and the 5GC may be simply referred to as a network.

[0015] The base station 100 is a radio base station conforming to NR, and performs NR radio communication with the terminal 200. The base station 100 and the terminal 200 are capable of supporting Massive MIMO (Multi-Input Multi-Output), which generates a more directional beam by controlling radio signals transmitted from multiple antenna elements, Carrier Aggregation (CA), which uses multiple component carriers (CCs) by bundling them together, and Dual Connectivity (DC), which performs simultaneous communication between multiple NG-RAN nodes and the terminal.

[0016] The wireless communication system 10 supports FR1 and FR2. The frequency bands of each FR (Frequency Range) are as follows: FR1: 410 MHz to 7.125 GHz FR2: 24.25 GHz to 52.6 GHz

[0017] FR1 may use a sub-carrier spacing (SCS) of 15 kHz, 30 kHz, or 60 kHz, and may use a bandwidth (BW) of 5 to 100 MHz. FR2 is a higher frequency than FR1, and may use an SCS of 60 kHz or 120 kHz (including 240 kHz), and may use a bandwidth (BW) of 50 to 400 MHz.

[0018] Note that SCS may be interpreted as numerology, which is defined in 3GPP TS38.300 and corresponds to one subcarrier spacing in the frequency domain.

[0019] Furthermore, the wireless communication system 10 may also support frequency bands higher than the FR2 frequency band. Specifically, the wireless communication system 10 may support frequency bands above 52.6 GHz up to 114.25 GHz. For convenience, such high frequency bands may be referred to as "FR2x." When using a frequency band above 52.6 GHz, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) / Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) with a larger SCS may be applied.

[0020] <Radio Frame, Subframe, and Slot Configuration> Figure 2 is a diagram showing an example of the configuration of a radio frame, subframe, and slot used in the wireless communication system 10. As shown in Figure 2, one slot is composed of 14 symbols, and the larger (wider) the SCS, the shorter the symbol period (and slot period). Note that the number of symbols constituting one slot does not necessarily have to be 14 symbols (e.g., 28 or 56 symbols). Also, the number of slots per subframe may differ depending on the SCS. Furthermore, the SCS may be wider than 240 kHz.

[0021] The time direction (t) shown in Fig. 2 may be called a time domain, a time region, a symbol period, a symbol time, etc. The frequency direction may be called a frequency domain, a resource block, a resource block group, a subcarrier, a BWP (Bandwidth Part), a subchannel, a common frequency resource, etc.

[0022] <Protocol Stack> Figure 3 shows an example of an NR protocol stack. As shown in Figure 3, the NR protocol stack is divided into a user plane (U-Plane) protocol stack and a control plane (C-Plane) protocol stack.

[0023] The U-plane protocol stack processes user data. The terminal (UE) and base station (gNB) have a protocol stack consisting of PHY (physical), MAC (medium access control), RLC (radio link control), PDCP (packet data convergence protocol), and SDAP (service data adaptation protocol) in the U-plane protocol stack. NR Layer 2 (L2) is divided into MAC, RLC, PDCP, and SDAP sublayers.

[0024] The C-Plane protocol stack processes control data such as signaling messages. In the C-Plane protocol stack, the terminal and the base station have protocol stacks of PHY, MAC, RLC, PDCP, and RRC (Radio Resource Control). In addition, the terminal and the AMF (Access and Mobility Management Function) have a protocol stack of NAS (Medium Access Control).

[0025] <PDCP Functions> PDCP (PDCP layer) supports, for example, the following functions (see, for example, Chapter 4.4 of Non-Patent Document 1): Data transfer (U-Plane or C-Plane) Maintenance of PDCP SN (Sequence Number) Compression and decompression of headers using the RObust Header Compression (ROHC) protocol Compression and decompression of headers using the Ethernet Header Compression (EHC) protocol Compression and decompression of uplink data using the Uplink Data Compression (UDC) protocol Ciphering and deciphering (deciphering) Integrity protection and integrity verification Timer-based SDU (Service Data Unit) discarding Routing for split bearers and DAPS (Dual Active Protocol Stack) bearers Duplication Reordering and in-order delivery (or delivery or sending) Out-of-order delivery Duplicate discarding

[0026] <PDCP PDU> PDCP PDU (Protocol Data Unit) is divided into data PDU and control PDU.

[0027] A data PDU contains a PDCP SN, which is assigned by the transmitting PDCP entity. The length of the PDCP SN is 12 or 18 bits and is set by the upper layer (pdcp-SN-SizeUL, pdcp-SN-SizeDL, or sl-PDCP-SN-Size). The PDCP SN ranges from 0 to (2pdcp-SN-SizeUL-1), (2pdcp-SN-SizeDL-1), or (2sl-PDCP-SN-Size-1). It is incremented each time a PDCP-PDU is generated and sent to the RLC layer, and after reaching its upper limit, it loops around (returning to 0). The transmitting PDCP entity performs encryption and tamper detection processing on the PDCP SDU (Service Data Unit), and then sends the PDCP PDU with the PDCP SN added as a header to the RLC layer. On the other hand, the receiving PDCP entity performs, for example, deciphering and tamper detection processing based on the COUNT value and PDCP SN, and determines whether the received data is delivered in order, whether there is any duplicate data, etc.

[0028] Control PDUs are divided into a control PDU for a PDCP status report, a control PDU for interspersed ROHC feedback, a control PDU for EHC feedback, and a control PDU for UDC feedback (see, for example, Chapter 6.2.3 of Non-Patent Document 2). The format of the control PDU for a PDCP status report is described below.

[0029] 4 shows the format of a PDCP control PDU for a PDCP status report. As shown in FIG. 4, the PDCP control PDU for a PDCP status report has fields of D / C, PDU Type, R, FMC, and Bitmap.

[0030] The D / C field indicates whether the corresponding PDCP PDU is a PDCP data PDU or a PDCP control PDU.

[0031] 5 is a diagram illustrating the D / C field. As shown in FIG. 5, the D / C field has a 1-bit field. When the D / C field is "0," it indicates that the corresponding PDCP PDU is a control PDU. When the D / C field is "1," it indicates that the corresponding PDCP PDU is a data PDU.

[0032] Since FIG. 4 shows the PDCP control PDU format for a PDCP status report, "0" is stored in the D / C field in FIG.

[0033] The PDU Type field indicates the type of control information contained in the corresponding PDCP control PDU.

[0034] 6 is a diagram illustrating the PDU Type field. As shown in FIG. 6, the PDU Type field has a 3-bit field. If the PDU Type field is "000", it indicates that the corresponding PDCP control PDU is a control PDU for a PDCP status report. If the PDU Type field is "001", it indicates that the corresponding PDCP control PDU is a control PDU for interspersed ROHC feedback. If the PDU Type field is "010", it indicates that the corresponding PDCP control PDU is a control PDU for EHC feedback. If the PDU Type field is "011", it indicates that the corresponding PDCP control PDU is a control PDU for UDC feedback.

[0035] Since FIG. 4 shows the PDCP control PDU format for a PDCP status report, "000" is stored in the PDU Type field in FIG.

[0036] The R field has a 4-bit field and is a reserved field.

[0037] The FMC (First Missing COUNT) field has a 32-bit field. The FMC field indicates the COUNT value (RX_DELIV) of the first (oldest) missing PDCP SDU within the reordering window (size: 2[pdcp-SN-SizeDL]-1 or 2[sl-PDCP-SN-Size]-1). In other words, the FMC or RX_DELIV indicates the COUNT value of the first (oldest) PDCP SDU that has not been delivered to the upper layer and is still waiting.

[0038] As shown in Figure 7, the COUNT value (or simply COUNT) is composed of an HFN (Hyper Frame Number) and a PDCP SN, and is 32 bits long. The size of the HFN is 32 bits minus the length of the PDCP SN (12 or 18 bits). Note that the COUNT does not circulate.

[0039] The Bitmap field has a variable bit field, which indicates which SDUs are missing and which SDUs are correctly received by the receiving PDCP entity.

[0040] <Consideration> In future wireless communication systems (e.g., 6G), data traffic is expected to increase compared to current wireless communication systems. Accordingly, it is expected that the length of the PDCP SN will be extended (e.g., to 32 bits) to manage PDCP PDUs. Note that "length" may be read as "size."

[0041] In addition, it is expected that the length of the COUNT value will also be extended (for example, to 64 bits) in accordance with the extension of the length of the PDCP SN (see FIG. 7).

[0042] If the length of the PDCP SN and COUNT values ​​is extended, the size of PDCP control PDUs, such as the control PDU for the PDCP status report, will increase, resulting in increased signaling overhead (related to Proposal 1 below).

[0043] In addition, it is expected that the dynamic range of throughput will expand in future wireless communication systems, and it is anticipated that different PDCP SN lengths will be used, for example, a 32-bit PDCP SN will be used for high traffic data, while a 12-bit PDCP SN will be used for low traffic data.

[0044] In the current specifications, when the PDCP SN length is changed in this way, PDCP reestablishment is required, which may result in delays or losses of PDCP-related data (e.g., PDCP data PDUs) due to the PDCP entity being reset (see Proposals 2 and 3 below). Furthermore, if there is a misunderstanding between the terminal and the base station regarding the timing at which the PDCP SN length change is applied or implemented, communication may not be performed properly (see Proposal 3 below).

[0045] Therefore, unless the operation related to the length of the PDCP SN and COUNT value is properly defined, there is a risk that the performance of the wireless communication system will be degraded due to increased signaling overhead, delays, loss, and the like.

[0046] Therefore, the following describes proposals (Proposals 1 to 3) for dealing with the above-mentioned problems when the length of the PDCP SN is extended.

[0047] As a premise for the proposal described below, for example, the maximum values ​​of the RRC parameters pdcp-SN-SizeUL, pdcp-SN-SizeDL, and / or sl-PDCP-SN-Size (i.e., the length of the PDCP SN) in the PDCP-Config information element and the SL-PDCP-Config information element may be extended. For example, the maximum values ​​of pdcp-SN-SizeUL, pdcp-SN-SizeDL, and / or sl-PDCP-SN-Size may be specified as 32 bits (e.g., len32bits), 64 bits (e.g., len64bits), etc. For example, pdcp-SN-SizeUL, pdcp-SN-SizeDL, and / or sl-PDCP-SN-Size may be selected from 12 bits, 18 bits, and 32 bits. The PDCP-Config information element and the SL-PDCP-Config information element may be referred to as (configuration) information related to PDCP, and pdcp-SN-SizeUL, pdcp-SN-SizeDL, and sl-PDCP-SN-Size may be referred to as (configuration) information indicating the length of a PDCP SN, (configuration) information related to the length of a PDCP SN, (configuration) information related to PDCP, etc. For example, base station 100 may transmit PDCP-related configuration information etc. to terminal 200, and terminal 200 may receive PDCP-related configuration information etc. from base station 100.

[0048] <Proposal 1> If the length of the PDCP SN and the length of the COUNT value are extended, the size of the FMC field of the PDCP status report will increase (for example, from the current 32 bits to 64 bits). To address this, terminal 200 may transmit a PDCP status report using the PDCP SN field to base station 100 (e.g., target base station (node) 100) instead of using the FMC field, as shown in FIG. 8 , during handover or reconnection, for example. As described above, the FMC, i.e., COUNT, is composed of the HFN and PDCP SN, and therefore the length of the PDCP SN is shorter than the length of the FMC (COUNT). Therefore, if the COUNT value is extended from the current 32 bits, using the PDCP SN field instead of the FMC field can suppress an increase in signaling overhead. Note that the PDCP status report may simply be referred to as a status report, and the PDCP SN may also be referred to as identification information, an identification number, an identifier, or the like of data or a data packet.

[0049] Also, for example, the length of the PDCP SN field (i.e., PDCP SN) may be 32 bits. By making the PDCP SN field 32 bits long, the format (size portion) in the current specification can be reused as the PDCP control PDU format for the PDCP status report, and the impact (changes) on the specification can be reduced.

[0050] Furthermore, terminal 200 may transmit the HFN portion constituting FMC (COUNT) to base station 100 by RRC (as an RRC parameter).

[0051] On the other hand, for example, when base station 100 starts PDCP re-establishment, base station 100 may receive a PDCP status report using a PDCP SN field instead of using an FMC field from terminal 200. Furthermore, base station 100 may receive an HFN from terminal 200 via RRC (as an RRC parameter).

[0052] In this way, the PDCP SN is transmitted from terminal 200 to base station 100 by a PDCP status report, and the HFN is transmitted from terminal 200 to base station 100 by RRC, thereby allowing the COUNT value to be shared between terminal 200 and base station 100 and enabling appropriate communication (such as retransmission control).

[0053] Next, an example of the operation of terminal 200 according to this embodiment in accordance with Proposal 1 will be described with reference to FIG.

[0054] For example, at the time of handover or reconnection, in step S11, terminal 200 generates a PDCP status report including the PDCP SN instead of a COUNT value including the PDCP SN.

[0055] In step S12 , terminal 200 transmits the generated PDCP status report to base station 100 .

[0056] As described above, according to Proposal 1, a PDCP status report using a PDCP SN, which is smaller in size than an FMC, is communicated instead of an FMC, thereby suppressing an increase in signaling overhead and preventing or suppressing degradation of the performance of the wireless communication system.

[0057] <Proposal 2> The terminal 200 (and the base station 100) may not perform PDCP re-establishment (i.e., may not perform the PDCP re-establishment procedure) when applying (or implementing) PDCP SN length modification (or when changing the PDCP SN length). In other words, the terminal 200 (and the base station 100) may apply PDCP SN length modification without performing PDCP re-establishment. Note that the procedure according to Proposal 2 described below may also be referred to as a PDCP SN length modification procedure, etc. Accordingly, the terminal 200 (and the base station 100) may perform the PDCP SN length modification procedure without performing PDCP re-establishment. Furthermore, in Proposal 2, the expression "applying PDCP SN length modification (or changing the PDCP SN length)" or similar expressions described below may be interpreted as "deciding to apply PDCP SN length modification (or changing the PDCP SN length)" or similar expressions.

[0058] (Option 2-1) The PDCP SN length may be changed via RRC. When the PDCP SN length (e.g., pdcp-SN-SizeUL, pdcp-SN-SizeDL, etc.) is reset from 18 bits to 32 bits (when terminal 200 receives reset information indicating the PDCP SN length from base station 100), terminal 200 (and base station 100) may apply the PDCP SN length change without re-establishing PDCP (or may simply apply the PDCP SN length to the reset 32 ​​bits).

[0059] When the PDCP SN length is changed (e.g., from 18 bits to 32 bits), the COUNT value itself may be the same as before the change. For example, if the length of the COUNT value is extended from the current 32 bits to 64 bits, the COUNT value itself may remain the same as before the change, and only the boundary between the HFN and the PDCP SN in the COUNT may be changed, as shown in Figure 9. In this way, when the COUNT value is extended, the size of the HFN is the length of the COUNT value (e.g., 64 bits) minus the length of the PDCP SN (12 bits, 18 bits, 32 bits, etc.).

[0060] (Option 2-2) The PDCP SN length may be changed via a PDCP control PDU. For example, terminal 200 may receive a PDCP control PDU such as that shown below from base station 100, and may change the PDCP SN length based on the received PDCP control PDU without re-establishing PDCP.

[0061] [Examples of PDCP Control PDU Formats] FIGS. 10 to 15 are diagrams showing examples of PDCP control PDU formats used to change the PDCP SN length.

[0062] In one example, the PDCP control PDU may be used to instruct a change to the PDCP SN length or to indicate the PDCP SN length after the change. For example, as shown in Fig. 10, the format of the PDCP control PDU transmitted from base station 100 to terminal 200 may include a field in Oct 2 indicating a change to the PDCP SN length or a changed PDCP SN length. When a field indicating a change to the PDCP SN length is used, for example, two PDCP SN lengths may be set in advance, and the PDCP SN length may be switched each time a change to the PDCP SN length is instructed.

[0063] In one example, the PDCP control PDU may be used for acknowledgment of the change of the PDCP SN length. For example, as shown in FIG. 11 , the format of the PDCP control PDU transmitted from terminal 200 to base station 100 may include a field in Oct 2 indicating an acknowledgment of the change of the PDCP SN length.

[0064] For example, when the PDCP control PDU shown in FIG. 10 is transmitted from base station 100 to terminal 200, and in response, the PDCP control PDU shown in FIG. 11 is transmitted from terminal 200 to base station 100, the PDCP SN length change may be applied.

[0065] In one example, the PDCP control PDU may be used for the PDCP COUNT value length. For example, as shown in FIG. 12 , the format of the PDCP control PDU transmitted from base station 100 to terminal 200 may include a field in Oct 2 that indicates the PDCP COUNT value length.

[0066] In one example, the PDCP control PDU may be used for a PDCP COUNT delimiter change instruction. For example, as shown in FIG. 13 , the format of the PDCP control PDU transmitted from base station 100 to terminal 200 may include a field indicating a PDCP COUNT delimiter change instruction in Oct 2. In this case, for example, two PDCP COUNT delimiters (positions) may be set in advance, and the PDCP COUNT delimiter (position) may be switched each time a PDCP COUNT delimiter change instruction is issued.

[0067] In one example, the PDCP control PDU may be used for the changed COUNT delimiter. For example, as shown in FIG. 14 , the format of the PDCP control PDU transmitted from base station 100 to terminal 200 may include a field in Oct 2 that indicates the changed COUNT delimiter (position).

[0068] In one example, the PDCP control PDU may be used for acknowledgment of the change of the COUNT delimiter. For example, as shown in FIG. 15 , the format of the PDCP control PDU transmitted from terminal 200 to base station 100 may include a field indicating the acknowledgment of the change of the COUNT delimiter in Oct 2.

[0069] For example, when the PDCP control PDU shown in FIG. 15 is transmitted from terminal 200 to base station 100 in response to the PDCP control PDU shown in FIG. 12, 13, or 14 being transmitted from base station 100 to terminal 200, a change in the COUNT delimiter (and therefore a change in the PDCP SN length) may be applied.

[0070] 10, 12, 13, or 14 may be transmitted from terminal 200 to base station 100, and the PDCP control PDUs shown in FIGS. 11 and 15 may be transmitted from base station 100 to terminal 200. In this case, for example, when the PDCP control PDU shown in FIG. 10 is transmitted from terminal 200 to base station 100, and in response to the PDCP control PDU shown in FIG. 11 being transmitted from base station 100 to terminal 200, a PDCP SN length change may be applied. Similarly, for example, when the PDCP control PDU shown in FIG. 15 is transmitted from base station 100 to terminal 200, in response to the PDCP control PDU shown in FIG. 12, 13, or 14 being transmitted from terminal 200 to base station 100, a change in COUNT delimiter (and therefore a change in PDCP SN length) may be applied.

[0071] The above-mentioned configuration information and PDCP control PDU indicating the PDCP SN length may also be referred to as change information indicating a PDCP SN length change from the currently applied PDCP SN length, information regarding the PDCP SN length change, information regarding the PDCP SN length, information regarding PDCP, etc.

[0072] On the other hand, base station 100 may decide to change the PDCP SN length from the currently applied PDCP SN, apply the PDCP SN length change without re-establishing PDCP, and transmit change information indicating the change in PDCP SN length from the currently applied PDCP SN length to terminal 200.

[0073] Next, an example of the operation of terminal 200 according to this embodiment in accordance with Proposal 2 will be described with reference to FIG.

[0074] In step S21, terminal 200 receives, from base station 100, change information indicating a change in the PDCP SN length from the currently applied PDCP SN length.

[0075] In step S22, in response to receiving the change information in step S21, terminal 200 applies the PDCP SN length change without re-establishing PDCP.

[0076] As described above, according to Proposal 2, the PDCP SN length can be changed by RRC or PDCP control PDU without the need for PDCP re-establishment, thereby preventing or suppressing delays and losses of PDCP-related data and preventing or suppressing performance degradation of the wireless communication system.

[0077] <Proposal 3> In relation to Proposal 2, when changing the PDCP SN length without re-establishing PDCP, the following issues arise: should the change be applied synchronously (at what timing) or asynchronously (at what timing)? If it is applied synchronously, how should it be synchronized? Therefore, this proposal describes options (Options 3-1 to 3-4) for addressing these issues. Note that the processing and interactions related to Proposal 2 (e.g., the processing shown in FIG. 17) may have already been performed before the processing and interactions related to Proposal 3 described below.

[0078] (Option 3-1) When synchronizing PDCP SN length changes, the timing for applying the PDCP SN length change may be notified. For example, terminal 200 may receive control information notifying the timing from base station 100. Also, for example, terminal 200 may transmit control information notifying the timing to base station 100. Terminal 200 and base station 100 may apply the PDCP SN length change at the timing based on the control information notifying the timing.

[0079] (Option 3-2) When the PDCP SN length change is synchronized, the PDCP SN length may be changed during RRC reconfiguration. For example, the PDCP SN length may be changed during reconfiguration with synchronization (reconfigurationWithSync). For example, terminal 200 may receive a "reconfigurationWithSync" information element from base station 100 and may apply the PDCP SN length change at the timing of receiving this information element, or base station 100 may apply the PDCP SN length change at the timing of transmitting this information element.

[0080] (Option 3-3) When the PDCP SN length change is not synchronized, a flag indicating the PDCP SN length or a flag indicating a PDCP SN length change may be provided in the PDCP data PDU header. For example, the flag may correspond to a predetermined reserved field in the PDCP data PDU format in the current specifications. For example, the terminal 200 may receive a PDCP data PDU with the flag set from the base station 100 and apply the PDCP SN length change at the timing of receiving the PDCP data PDU, and the base station 100 may apply the PDCP SN length change at the timing of transmitting the PDCP data PDU. Also, for example, the base station 100 may receive a PDCP data PDU with the flag set from the terminal 200 and apply the PDCP SN length change at the timing of receiving the PDCP data PDU, and the terminal 200 may apply the PDCP SN length change at the timing of transmitting the PDCP data PDU.

[0081] (Option 3-4) If the PDCP SN length change is not synchronized, base station 100 may halt transmission of new data (e.g., a new PDCP data PDU) until the above-described PDCP SN length change procedure is completed. For example, base station 100 may not transmit new data to terminal 200 until the above-described PDCP SN length change procedure is completed, and terminal 200 may assume that base station 100 will not transmit new data until the above-described PDCP SN length change procedure is completed. Furthermore, terminal 200 may assume that the PDCP SN length has been changed for new data received after the above-described PDCP SN length change procedure is completed. Therefore, terminal 200 may apply the PDCP SN length change at the timing of receiving the first PDCP data PDU after receiving the change information described in Proposal 2. Furthermore, for example, terminal 200 may not transmit new data to base station 100 until the above-described PDCP SN length change procedure is completed, and base station 100 may assume that terminal 200 will not transmit new data until the above-described PDCP SN length change procedure is completed. Furthermore, base station 100 may assume that the PDCP SN length has been changed for new data received after the above-described PDCP SN length change procedure has been completed, and therefore may apply the PDCP SN length change at the timing when the first PDCP data PDU is received after receiving the above-described change information in Proposal 2.

[0082] The above-mentioned control information and reconfigurationWithSync information element indicating the timing to apply the PDCP SN length change may also be referred to as timing information indicating the timing to apply the PDCP SN length change, timing information regarding the timing to apply the PDCP SN length change, information regarding the PDCP SN length change, etc. The PDCP data PDU may also be referred to as data, PDCP data, data packet, PDCP data packet, etc.

[0083] Next, the configurations of the base station 100 and the terminal 200 will be described. Note that the configurations of the base station 100 and the terminal 200 described below are examples of functions related to this embodiment. The base station 100 and the terminal 200 may have functions not shown. Furthermore, the names of the functional divisions and / or functional units are not limited as long as they are functions that perform operations related to this embodiment.

[0084] <Configuration of Base Station> Fig. 18 is a block diagram showing an example of the configuration of base station 100 according to this embodiment. Base station 100 includes, for example, a transmitting unit 101, a receiving unit 102, and a control unit 103. Base station 100 communicates with terminal 200 (see Fig. 19) by radio.

[0085] The transmitter 101 transmits a downlink (DL) signal to the terminal 200. For example, the transmitter 101 transmits the DL signal under the control of the controller 103.

[0086] For example, transmitting section 101 may transmit to terminal 200 (setting) information regarding PDCP, change information indicating a PDCP SN length change from the currently applied PDCP SN length, timing information indicating the timing at which the PDCP SN length change is applied, a PDCP data packet including information indicating the PDCP SN length (such as a flag), a PDCP data packet, etc.

[0087] The DL signal may include, for example, a downlink data signal and control information (e.g., Downlink Control Information (DCI)). The DL signal may also include information indicating scheduling related to signal transmission of the terminal 200 (e.g., an UL grant). The DL signal may also include control information of higher layers (e.g., control information of Radio Resource Control (RRC)). The DL signal may also include a reference signal.

[0088] The channels used for transmitting DL signals include, for example, a downlink data channel and a downlink control channel. For example, the downlink data channel may include a PDSCH (Physical Downlink Shared Channel), and the downlink control channel may include a PDCCH (Physical Downlink Control Channel). For example, the base station 100 transmits downlink control information to the terminal 200 using the PDCCH and transmits downlink data signals using the PDSCH.

[0089] The reference signal included in the DL signal may include at least one of a demodulation reference signal (Demodulation Reference Signal (DMRS)), a Phase Tracking Reference Signal (PTRS), a Channel State Information-Reference Signal (CSI-RS), a Sounding Reference Signal (SRS), and a Positioning Reference Signal (PRS) for position information. For example, reference signals such as DMRS and PTRS are used for demodulating downlink data signals and are transmitted using the PDSCH.

[0090] The receiving unit 102 receives an uplink (UL) signal transmitted from the terminal 200. For example, the receiving unit 102 receives the UL signal under the control of the control unit 103.

[0091] For example, receiving unit 102 may receive from terminal 200 a PDCP status report including a PDCP SN (e.g., in response to the start of PDCP re-establishment) instead of a count value including the PDCP SN, an RRC parameter indicating the hyperframe number included in the count value, a PDCP data packet including information indicating the PDCP SN length (such as a flag), a PDCP data packet, etc.

[0092] The transmitting unit 101 and the receiving unit 102 may be collectively referred to as a communication unit.

[0093] The control unit 103 controls the communication operations of the base station 100 , including the transmission processing of the transmission unit 101 and the reception processing of the reception unit 102 .

[0094] For example, the control unit 103 acquires information such as data and control information from the upper layer and outputs it to the transmitting unit 101. The control unit 103 also outputs the data, control information, etc. received from the receiving unit 102 to the upper layer.

[0095] For example, the control unit 103 allocates resources (or channels) used for transmitting and receiving DL signals and / or resources used for transmitting and receiving UL signals based on signals (e.g., data and control information, etc.) received from the terminal 200 and / or data and control information, etc. acquired from a higher layer. Information on the allocated resources may be included in control information transmitted to the terminal 200.

[0096] For example, control unit 103 may perform PDCP re-establishment, including initiating PDCP re-establishment. Alternatively, for example, control unit 103 may change the PDCP SN length from the currently applied PDCP SN length without performing PDCP re-establishment.

[0097] 19 is a block diagram showing an example of the configuration of terminal 200 according to this embodiment. Terminal 200 includes, for example, receiving section 201, transmitting section 202, and control section 203. Terminal 200 communicates with base station 100, for example, wirelessly.

[0098] The receiving unit 201 receives a DL signal transmitted from the base station 100. For example, the receiving unit 201 receives the DL signal under the control of the control unit 203.

[0099] For example, the receiving unit 201 may receive from the base station 100 (setting) information regarding PDCP, change information indicating a PDCP SN length change from the currently applied PDCP SN length, timing information indicating the timing to apply the PDCP SN length change, a PDCP data packet including information indicating the PDCP SN length (such as a flag), and the like.

[0100] The transmitting unit 202 transmits the UL signal to the base station 100. For example, the transmitting unit 202 transmits the UL signal under the control of the control unit 203.

[0101] For example, the transmitting unit 202 may transmit to the base station 100 a PDCP status report that includes a PDCP SN (e.g., 32 bits in length) instead of a count value that includes the PDCP SN, an RRC parameter that indicates the hyperframe number included in the count value, a PDCP data packet that includes information (such as a flag) that indicates the PDCP SN length, a PDCP data packet, or the like.

[0102] The UL signal may include, for example, an uplink data signal and control information (e.g., UCI). For example, information related to the processing capability of the terminal 200 (e.g., UE capability) may be included. The UL signal may also include a reference signal.

[0103] Channels used for transmitting UL signals include, for example, an uplink data channel and an uplink control channel. For example, the uplink data channel includes a PUSCH (Physical Uplink Shared Channel), and the uplink control channel includes a PUCCH (Physical Uplink Control Channel). For example, terminal 200 transmits uplink control information to base station 100 using the PUCCH and transmits uplink data signals using the PUSCH.

[0104] The reference signals included in the UL signal may include, for example, at least one of DMRS, PTRS, CSI-RS, SRS, and PRS. For example, the reference signals such as DMRS and PTRS are used for demodulating the uplink data signal and are transmitted using an uplink channel (for example, PUSCH).

[0105] The receiving unit 201 and the transmitting unit 202 may be collectively referred to as a communication unit.

[0106] The control unit 203 controls the communication operations of the terminal 200 , including the reception processing in the receiving unit 201 and the transmission processing in the transmitting unit 202 .

[0107] For example, the control unit 203 acquires information such as data and control information from the upper layer and outputs it to the transmitting unit 202. Also, the control unit 203 outputs, for example, the data and control information received from the receiving unit 201 to the upper layer.

[0108] For example, the control unit 203 controls transmission of information to be fed back to the base station 100. The information to be fed back to the base station 100 may include, for example, HARQ-ACK, Channel State Information (CSI), or a Scheduling Request (SR). The information to be fed back to the base station 100 may be included in the UCI.

[0109] For example, control unit 203 may generate a PDCP status report that includes the PDCP SN instead of a count value that includes the PDCP SN. Furthermore, for example, control unit 203 may apply a PDCP SN length change without re-establishing PDCP communication in response to receiving unit 201 receiving change information indicating a change in the PDCP SN length from the currently applied PDCP SN length. Furthermore, for example, control unit 203 may apply a PDCP SN length change at the timing indicated by timing information received by receiving unit 201 ... Furthermore, for example, control unit 203 may apply a PDCP SN length change at the timing when receiving unit 201 receives a PDCP data packet that includes information (such as a flag) indicating the PDCP SN length after receiving the change information. Furthermore, for example, control unit 203 may apply a PDCP SN length change at the timing indicated by timing information received by receiving unit 201. Furthermore, for example, control unit 203 may apply a PDCP SN length change at the timing when receiving unit 201 receives the first PDCP data packet after receiving the change information.

[0110] Note that the channel used for transmitting the DL signal and the channel used for transmitting the UL signal are not limited to the above-mentioned example. For example, the channel used for transmitting the DL signal and the channel used for transmitting the UL signal may include a Random Access Channel (RACH) and a Physical Broadcast Channel (PBCH). The RACH may be used to transmit Downlink Control Information (DCI) including a Random Access Radio Network Temporary Identifier (RA-RNTI), for example.

[0111] With the above configuration, it is possible to prevent or suppress degradation of the wireless communication system when the length of the PDCP SN is extended.

[0112] <Summary of the embodiment> As described above, according to one aspect of the present disclosure, there is provided a terminal including: a control unit that generates a PDCP status report that includes a Packet Data Convergence Protocol Sequence Number (PDCP SN) instead of a count value that includes the PDCP SN; and a transmission unit that transmits the PDCP status report to a base station.

[0113] The above configuration makes it possible to suppress an increase in signaling overhead and to prevent or suppress degradation of the performance of the wireless communication system.

[0114] In one example, the PDCP SN is 32 bits long.

[0115] The above configuration can reduce the impact (changes) on specifications.

[0116] In one example, the transmitter transmits a radio resource control (RRC) parameter to the base station indicating a hyperframe number included in the count value.

[0117] With the above configuration, the count value can be shared between the terminal and the base station.

[0118] According to one aspect of the present disclosure, there is provided a base station including: a control unit that initiates PDCP re-establishment; and a receiving unit that receives, in response to the initiation of the PDCP re-establishment, a PDCP status report from a terminal, the PDCP status report including the PDCP SN instead of a count value including the PDCP SN.

[0119] The above configuration makes it possible to suppress an increase in signaling overhead and to prevent or suppress degradation of the performance of the wireless communication system.

[0120] According to one aspect of the present disclosure, there is provided a communication control method in which a terminal generates a PDCP status report including a PDCP SN instead of a count value including the PDCP SN, and transmits the PDCP status report to a base station.

[0121] The above configuration makes it possible to suppress an increase in signaling overhead and to prevent or suppress degradation of the performance of the wireless communication system.

[0122] According to one aspect of the present disclosure, there is provided a terminal including: a receiving unit that receives, from a base station, modification information indicating a change in PDCP SN length from a currently applied PDCP SN length; and a control unit that, in response to the receiving unit receiving the modification information, applies the PDCP SN length change without re-establishing PDCP.

[0123] With the above configuration, it is possible to prevent or suppress delays and losses of data related to PDCP, and to prevent or suppress degradation of performance of the wireless communication system.

[0124] In one example, the receiving unit receives timing information from the base station indicating a timing for applying the PDCP SN length change, and the control unit applies the PDCP SN length change at the timing indicated by the timing information.

[0125] With the above configuration, the PDCP SN length change can be applied without misunderstanding between the terminal and the base station.

[0126] In one example, the control unit applies the PDCP SN length change at the timing when the receiving unit receives a PDCP data packet including information indicating the PDCP SN length after receiving the change information from the base station.

[0127] With the above configuration, the PDCP SN length change can be applied without misunderstanding between the terminal and the base station.

[0128] In one example, the control unit applies the PDCP SN length modification at the timing when the receiving unit receives the first PDCP data packet after receiving the modification information from the base station.

[0129] With the above configuration, the PDCP SN length change can be applied without misunderstanding between the terminal and the base station.

[0130] According to one aspect of the present disclosure, there is provided a base station including: a control unit that applies a PDCP SN length change from a currently applied PDCP SN length without performing PDCP re-establishment; and a transmission unit that transmits change information indicating the PDCP SN length change to a terminal.

[0131] With the above configuration, it is possible to prevent or suppress delays and losses of data related to PDCP, and to prevent or suppress degradation of performance of the wireless communication system.

[0132] According to one aspect of the present disclosure, there is provided a communication control method in which a terminal receives, from a base station, change information indicating a change in PDCP SN length from a currently applied PDCP SN length, and, in response to receiving the change information, applies the changed PDCP SN length without re-establishing PDCP.

[0133] With the above configuration, it is possible to prevent or suppress delays and losses of data related to PDCP, and to prevent or suppress degradation of performance of the wireless communication system.

[0134] The present disclosure has been described above. Note that the division of items in the above description is not essential to the present disclosure, and items described in two or more items may be used in combination as needed, and items described in one item may be applied to items described in another item (unless they are inconsistent).

[0135] <Hardware Configuration, etc.> The block diagrams used to explain the above embodiments show functional blocks. 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 a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (e.g., using wires, wirelessly, etc.) and these multiple devices. The functional block may also be realized by combining software with the single device or the multiple devices.

[0136] Functions include, but are not limited to, judgment, determination, assessment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how these functions are implemented.

[0137] For example, a base station, a terminal, or the like according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 20 is a diagram illustrating an example of the hardware configuration of a base station and a terminal according to this embodiment. The above-described base station 100 and terminal 200 may be physically 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.

[0138] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of base station 100 and terminal 200 may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0139] Each function in the base station 100 and the terminal 200 is realized by loading specified software (programs) onto hardware such as the processor 1001 and the memory 1002, causing the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of reading and writing data in the memory 1002 and the storage 1003.

[0140] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 103 and control unit 203 may be realized by the processor 1001.

[0141] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 203 of the terminal 200 may be implemented by a control program stored in the memory 1002 and running on the processor 1001, and similar implementations may be made for other functional blocks. While the above-described various processes have been described as being executed by one processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may also be transmitted from a network via a telecommunications line.

[0142] The memory 1002 is a computer-readable recording medium and may be configured by, for example, at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 can store executable programs (program codes), software modules, etc. for implementing a wireless communication method according to an embodiment of the present disclosure.

[0143] Storage 1003 is a computer-readable recording medium, and may be composed of at least one of, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned storage medium may be, for example, a database, a server, or other appropriate medium including at least one of memory 1002 and storage 1003.

[0144] 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, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include 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). For example, the above-mentioned transmitter 101, receiver 102, receiver 201, transmitter 202, etc. may be realized by the communication device 1004.

[0145] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0146] Furthermore, 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 each device.

[0147] Furthermore, base station 100 and terminal 200 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, processor 1001 may be implemented using at least one of these pieces of hardware.

[0148] <Notification of Information, Signaling> Notification of information is not limited to the embodiments described in the present disclosure and may be performed using other methods. For example, notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination thereof. Furthermore, RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0149] <Applicable Systems> The embodiments described in the present disclosure are applicable to LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.17 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 (WiMAX (registered trademark)), IEEE 802.30 (WiMAX (registered trademark)), IEEE 802.31 (Wi-Fi (registered trademark)), IEEE 802.32 (WiMAX (registered trademark)), IEEE 802.33 (WiMAX (registered trademark)), IEEE 802.34 (WiMAX (registered trademark The present invention may be applied to at least one of systems using 802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), or other suitable systems, and next-generation systems that are extended, modified, created, or defined based on these systems. The present invention may also be applied to a combination of multiple systems (e.g., a combination of LTE and / or LTE-A with 5G).

[0150] <Processing Procedures, etc.> The processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be rearranged unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0151] <Operation of Base Station> In the present disclosure, specific operations described as being performed by a base station may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (for example, an MME or an S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (for example, an MME and an S-GW) may also be used.

[0152] <Direction of Input / Output> Information, etc. (see <Information, Signal>) can be output from a higher layer (or a lower layer) to a lower layer (or a higher layer). It may also be input / output via multiple network nodes.

[0153] <Handling of Input / Output Information, etc.> Input / output information, etc. may be stored in a specific location (for example, memory) or may be managed using a management table. Input / output information, etc. may be overwritten, updated, or added. Output information, etc. may be deleted. Input information, etc. may be sent to another device.

[0154] <Determination method> The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0155] <Variations of Aspects, etc.> Each aspect / embodiment described in the present disclosure may be used alone, in combination, or switched depending on the implementation. In addition, notification of predetermined information (e.g., notification that "X is true") is not limited to being done explicitly, but may be done implicitly (e.g., by not notifying the predetermined information).

[0156] 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 herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0157] <Software> Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0158] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0159] 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., which may be referred to throughout the above description, may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0160] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0161] <System, Network> As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0162] <Parameter and Channel Names> Furthermore, the information, parameters, and the like described in the present disclosure may be expressed using absolute values, relative values ​​from a predetermined value, or other corresponding information. For example, a radio resource may be indicated by an index.

[0163] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0164] <Base Station> In the present disclosure, terms such as "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," "carrier," and "component carrier" may be used interchangeably. A base station may also be referred to by terms such as a macrocell, a small cell, a femtocell, and a picocell.

[0165] A base station can accommodate one or more (e.g., three) cells. When 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 can also be provided with communication services by a base station subsystem (e.g., a remote radio head (RRH)). The terms "cell" or "sector" refer to part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0166] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0167] Mobile Station In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," and the like may be used interchangeably.

[0168] A mobile station may also be referred to 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 terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0169] <Base Station / Mobile Station> At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object refers to a movable object, and may move at any speed. Naturally, this also includes cases where the mobile object is stationary. Examples of the mobile object include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and objects mounted thereon. The mobile object may also be an autonomous mobile object operating based on an operational command. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0170] Furthermore, the base station in the present disclosure may be read as a terminal. For example, the embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the terminal 200 may be configured to have the functions of the base station 100 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to communication between terminals (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0171] Similarly, the term "terminal" in the present disclosure may be read as "base station." In this case, the base station 100 may be configured to have the functions of the terminal 200 described above.

[0172] Fig. 21 shows an example configuration of a vehicle 2001. As shown in Fig. 21, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in the present disclosure may be applied to a communication device mounted on the vehicle 2001, and may be applied to the communication module 2013, for example.

[0173] The drive unit 2002 is configured, for example, by an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) 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.

[0174] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2029 provided in the vehicle 2001. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0175] The signals from the various sensors 2021 to 2029 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0176] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing (outputting) various types of information, such as driving information, traffic information, and entertainment information, and one or more ECUs that control these devices. The information service unit 2012 provides various types of multimedia information and multimedia services to the occupants of the vehicle 2001 by using information acquired from external devices via the communication module 2013, etc.

[0177] The information service unit 2012 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0178] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driving burden on the driver, such as 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, as well as one or more ECUs that control these devices. In addition, the driving assistance system unit 2030 transmits and receives various information via the communication module 2013 to realize the driving assistance function or the autonomous driving function.

[0179] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 29, which are provided in the vehicle 2001.

[0180] 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 an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0181] The communication module 2013 may transmit at least one of signals from the above-mentioned various sensors 2021 to 2029 input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021 to 2029, the information service unit 2012, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above-mentioned input.

[0182] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from an external device and displays it on the information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH received by the communication module 2013 (or data / information decoded from the PDSCH)).

[0183] Furthermore, the communication module 2013 stores various information received from external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, sensors 2021 to 2029, and the like provided in the vehicle 2001.

[0184] <Meaning and Interpretation of Terms> As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching a table, database, or other data structure), ascertaining something that is considered to be a "judging" or "determining," and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like that are considered to be a "judging" or "determining." Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0185] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0186] <Reference Signal> A reference signal can also be abbreviated as RS (Reference Signal), and may also be called a pilot depending on the applicable standard.

[0187] <Meaning of "based on"> As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0188] "First," "Second" Any reference to an element using designations such as "first," "second," etc., 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, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some way.

[0189] <Means> The "means" in the configuration of each device above may be replaced with "section," "circuit," "device," etc.

[0190] Open Format: When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0191] <Time Units such as TTI, Frequency Units such as RB, and Radio Frame Configuration> A radio frame may be composed of one or more frames in the time domain. Each of the one or more 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 (e.g., 1 ms) that is independent of numerology.

[0192] Numerology may be a communication parameter that applies to the transmission and / or reception of a signal or channel, and may indicate, for example, at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0193] A slot may be composed of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol). A slot may be a time unit based on numerology.

[0194] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0195] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0196] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc. instead of a subframe.

[0197] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. Note that the definition of TTI is not limited to this.

[0198] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0199] When one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0200] A TTI having a time length of 1 ms may be called a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0201] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and greater than or equal to 1 ms.

[0202] A resource block (RB) is a resource allocation unit in the time domain and the 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 numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0203] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0204] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0205] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0206] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a Common Reference Point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

[0207] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0208] 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 the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0209] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples, and various changes may be made to 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 subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc.

[0210] <Maximum Transmit Power> The "maximum transmit power" in the present disclosure may refer to the maximum value of transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0211] Articles In this disclosure, where 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.

[0212] <"Different"> 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 "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0213] One aspect of the present disclosure is useful in wireless communication systems.

[0214] 10 Wireless communication system 100 Base station 200 Terminal 101, 202 Transmitter 102, 201 Receiver 103, 203 Controller

Claims

1. A terminal comprising: a receiving unit that receives from a base station change information indicating a change in the Packet Data Convergence Protocol (PDCP) sequence number (SN) length from the currently applied PDCP SN length; and a control unit that applies the PDCP SN length change without performing PDCP re-establishment in response to the receiving unit receiving the change information.

2. The terminal according to claim 1, wherein the receiving unit receives from the base station timing information indicating the timing at which the PDCP SN length change is to be applied, and the control unit applies the PDCP SN length change at the timing indicated by the timing information.

3. The terminal according to claim 1, wherein the control unit applies the PDCP SN length change at the timing when the receiving unit receives a PDCP data packet including information indicating the PDCP SN length after receiving the change information from the base station.

4. The terminal according to claim 1, wherein the control unit applies the PDCP SN length change at the timing when the receiving unit first receives a PDCP data packet after receiving the change information from the base station.

5. A base station comprising: a control unit that applies a change in the PDCP SN length from the currently applied PDCP SN length without performing PDCP re-establishment; and a transmitting unit that transmits to the terminal change information indicating the PDCP SN length change.

6. A communication control method, wherein a terminal receives from a base station change information indicating a change in the PDCP SN length from the currently applied PDCP SN length, and applies the PDCP SN length change without performing PDCP re-establishment in response to receiving the change information.

Images