Communication device and communication method

Abstract

This communication device is provided with: a reception unit that receives a paging message from an ambient IoT (Internet of Things) reader; and a control unit that executes, on the basis of the paging message, a 2-step contention-based random access procedure or a contention-free random access procedure with the ambient IoT reader. The reception unit receives, from the ambient IoT reader, a message instructing a fallback to a 4-step contention-based random access procedure, and the control unit executes the 4-step contention-based random access procedure with the ambient IoT reader.

Description

Communication device and communication method

[0001] The present invention relates to a communication device and a communication method in a wireless communication system.

[0002] For NR (New Radio) (also known as "5G"), the successor system to LTE (Long Term Evolution), technologies are being considered that satisfy the requirements of a large-capacity system, high-speed data transmission speed, low latency, simultaneous connection of a large number of terminals, low cost, and low power consumption (for example, Non-Patent Document 1).

[0003] Furthermore, Release 18 of 3GPP (registered trademark) is studying Ambient Internet of Things (A-IoT) (see, for example, Non-Patent Document 2). Ambient IoT targets devices with extremely simple configurations for the lowest-end IoT applications that operate with extremely low power consumption.

[0004] 3GPP TS 38.300 V18.0.0 (2023-12)"New SID: Study on solutions for Ambient IoT (Internet of Things) in NR", RP-234058, 3GPP TSG RAN Meeting #102, December 20233GPP TR 38.848 V18.0.0 (2023-09)

[0005] When an ambient IoT device performs two-step contention-based random access or contention-free access, it is expected that random access may fail due to a deterioration in the wireless environment. In this case, the device needs to retry random access using an appropriate procedure.

[0006] The present invention has been made in view of the above points, and aims to improve the reliability of random access procedures for ambient IoT (Internet of Things) devices.

[0007] According to the disclosed technology, there is provided a communication device having a receiving unit that receives a paging message from an ambient Internet of Things (IoT) reader, and a control unit that executes a two-step contention-based random access procedure or a contention-free random access procedure with the ambient IoT reader based on the paging message, wherein the receiving unit receives a message from the ambient IoT reader instructing a fallback to a four-step contention-based random access procedure, and the control unit executes the four-step contention-based random access procedure with the ambient IoT reader.

[0008] According to the disclosed technology, it is possible to improve the reliability of random access procedures for ambient Internet of Things (IoT) devices.

[0009] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. FIG. 1 is a diagram illustrating an example of a system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a topology (1) according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a topology (2) according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of an architecture (1) according to an embodiment of the present invention. FIG. 5 is a diagram illustrating an example of an architecture (2) according to an embodiment of the present invention. FIG. 6 is a sequence diagram illustrating an example of a random access procedure (1) according to an embodiment of the present invention. FIG. 7 is a sequence diagram illustrating an example of a random access procedure (2) according to an embodiment of the present invention. FIG. 8 is a sequence diagram illustrating an example of a random access procedure (3) according to an embodiment of the present invention. FIG. 9 is a diagram illustrating a protocol stack according to an embodiment of the present invention. FIG. 10 is a sequence diagram illustrating an example of a random access procedure (4) according to an embodiment of the present invention. FIG. 11 is a sequence diagram illustrating an example of a random access procedure (5) according to an embodiment of the present invention. FIG. 12 is a sequence diagram illustrating an example of a random access procedure (6) according to an embodiment of the present invention. FIG. 13 is a sequence diagram illustrating an example of a random access procedure (7) according to an embodiment of the present invention. FIG. 14 is a sequence diagram illustrating an example of a random access procedure (8) according to an embodiment of the present invention. FIG. 15 is a sequence diagram illustrating an example of a random access procedure (9) according to an embodiment of the present invention. FIG. 16 is a diagram illustrating an example of the functional configuration of a base station 10 according to an embodiment of the present invention. FIG. 17 is a diagram illustrating an example of the functional configuration of a terminal 20 according to an embodiment of the present invention. FIG. 18 is a diagram illustrating an example of the hardware configuration of a base station 10 or a terminal 20 according to an FIG. 2 is a diagram showing an example of the configuration of a vehicle 2001 according to an embodiment of the present invention.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] In the operation of the wireless communication system according to the embodiment of the present invention, existing technology is used as appropriate. However, the existing technology is, for example, the existing LTE, but is not limited to the existing LTE. Furthermore, the term "LTE" used in this specification has a broad meaning including LTE-Advanced and systems subsequent to LTE-Advanced (e.g., NR), unless otherwise specified.

[0012] In addition, in the embodiments of the present invention described below, terms such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel) used in existing LTE are used. This is for convenience of description, and similar signals, functions, etc. may be called by other names. In addition, the above-mentioned terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, etc. However, even if a signal is used in NR, it is not necessarily stated as "NR-".

[0013] Furthermore, in the embodiment of the present invention, the duplex method may be a time division duplex (TDD) method, a frequency division duplex (FDD) method, or another method (for example, flexible duplex, etc.).

[0014] Furthermore, in the embodiments of the present invention, "configuring" radio parameters etc. may mean that predetermined values ​​are pre-configured, or that radio parameters notified from the base station 10 or the terminal 20 are set.

[0015] Fig. 1 is a diagram showing a configuration example (1) of a wireless communication system according to an embodiment of the present invention. As shown in Fig. 1, the wireless communication system according to the embodiment of the present invention includes a base station 10 and a terminal 20. Although Fig. 1 shows one base station 10 and one terminal 20, this is an example, and there may be a plurality of each.

[0016] The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of a wireless signal are defined in the time domain and the frequency domain. The time domain may be defined by the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. The base station 10 transmits a synchronization signal and system information to the terminal 20. The synchronization signal is, for example, NR-PSS and NR-SSS. The system information is, for example, transmitted via NR-PBCH and is also referred to as broadcast information. The synchronization signal and system information may also be referred to as SSB (SS / PBCH block). As shown in FIG. 1 , the base station 10 transmits control signals or data to the terminal 20 via DL (Downlink) and receives control signals or data from the terminal 20 via UL (Uplink). Both the base station 10 and the terminal 20 are capable of transmitting and receiving signals by performing beamforming. Furthermore, both the base station 10 and the terminal 20 can apply MIMO (Multiple Input Multiple Output) communication to DL or UL. Furthermore, both the base station 10 and the terminal 20 may communicate via a secondary cell (SCell: Secondary Cell) and a primary cell (PCell: Primary Cell) using CA (Carrier Aggregation). Furthermore, the terminal 20 may communicate via a primary cell of the base station 10 and a primary secondary cell group cell (PSCell: Primary SCG Cell) of another base station 10 using DC (Dual Connectivity).

[0017] The terminal 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, or an M2M (Machine-to-Machine) communication module. As shown in Fig. 1, the terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system. The terminal 20 also receives various reference signals transmitted from the base station 10 and measures propagation path quality based on the reception results of the reference signals.

[0018] The terminal 20 is capable of performing carrier aggregation, which aggregates multiple cells (multiple CCs (Component Carriers)) to communicate with the base station 10. In carrier aggregation, one PCell (Primary cell) and one or more SCells (Secondary cells) are used. Also, a PUCCH-SCell having a PUCCH may be used.

[0019] Here, a communication standard targeting devices with extremely simple configurations for the lowest-end IoT applications that operate with extremely low power consumption is being discussed in 3GPP (e.g., Non-Patent Document 2). This communication standard may be called, for example, Ambient Internet of Things (AIoT) or by other names. An ambient IoT device may be considered to be a device that receives power from energy harvesting. For example, an ambient IoT device may be considered to be a device that receives power from a continuous wave (CW) signal supplied from a base station or a reader.

[0020] For example, ambient IoT can be considered for the following deployment scenarios and characteristics:

[0021] 1) Indoor or outdoor environment. 2) Base station characteristics, e.g., macro, micro, or pico cell-based deployment. 3) Connectivity topology, e.g., which nodes (e.g., base stations, UEs, relays, repeaters, etc.) communicate with ambient IoT devices. 4) TDD or FDD, licensed or unlicensed frequency band. 5) Coexistence with UEs and infrastructure in frequency bands for existing 3GPP technologies. 6) Traffic assumptions originating from and / or terminating to the device.

[0022] RAN design targets based on the above deployment scenarios and characteristics for relevant use cases may include at least the following aspects:

[0023] 1) Power consumption 2) Complexity 3) Coverage 4) Data rate 5) Positioning accuracy

[0024] The feasibility of RAN design targets for use cases based on suitable deployment scenarios may be weighed to clarify expectations of required functionality to be supported.

[0025] For example, the following device categories may be envisioned for ambient IoT:

[0026] Device A has no power storage and is not capable of independent signal generation and amplification. Backscattering transmission is possible.

[0027] Device B has power storage and is not capable of independent signal generation. It is capable of backscatter transmission and amplifying the reflected signal using the stored power.

[0028] Device C has power storage and is capable of independently generating a signal, i.e., it has active RF components for transmission.

[0029] The complexity of device A may be assumed to be about the same as that of an RFID.

[0030] 2 is a diagram illustrating an example of a system according to an embodiment of the present invention. As shown in FIG. 2, in step 1, an Ambient IoT reader, which may be a BS or a UE, sends an R2D message to an Ambient IoT device (e.g., an RFID tag). The R2D message is a message from the reader to the device. In step 2, the Ambient IoT device sends a D2R message to the Ambient IoT reader. The D2R message is a message from the device to the reader. In step 3, the Ambient IoT reader reports to the Access and Mobility Management Function (AMF) of the CN or the new node.

[0031] For ambient IoT devices, compact protocol stacks and reduced signaling procedures are being considered to enable device-originating - device-terminated triggered (DO-DTT) and device-terminated (DT) data transmission, including paging, random access, data transmission including radio resource control aspects, and higher layer operations.

[0032] For example, the following network topology may be envisaged for ambient IoT (see Non-Patent Document 3):

[0033] FIG. 3 is a diagram showing an example topology (1) according to an embodiment of the present invention. The topology 1 shown in FIG. 3 is a configuration in which a BS and an ambient IoT device communicate with each other. The ambient IoT device performs bidirectional communication directly with the base station. Furthermore, the BS is connected to an access and mobility management function (AMF) or a new node in a core network (CN). Hereinafter, the CN may refer to any node on the network.

[0034] FIG. 4 is a diagram illustrating an example topology (2) according to an embodiment of the present invention. The topology 2 illustrated in FIG. 4 is a configuration in which a base station and an ambient IoT device communicate via an intermediate node. The ambient IoT device performs bidirectional communication with the intermediate node located between the base station and the ambient IoT device. The intermediate node may be, for example, a relay, an integrated access and backhaul (IAB) node, a UE, a repeater, or the like. The intermediate node may receive DL data or signaling intended for an AIot terminal from the base station and transmit the DL data or signaling to the AIot terminal.

[0035] The intermediate node and the BS may be connected via a Uu interface. Uu is a wireless interface between a Universal Terrestrial Radio Access Network (UTRAN) and a User Equipment (UE). The intermediate node may transmit unmodulated waves to the IoT terminal, receive UL data or signaling from the IoT terminal, and transmit the UL data or signaling to the BS. The BS may also be connected to an AMF or a new node in the CN.

[0036] Furthermore, the base station, intermediate node, support node, or other node transmits an RF signal to the ambient IoT device. The ambient IoT device is activated and obtains power from an RF operating field from the base station, intermediate node, support node, or other node via inductive coupling. The ambient IoT device transmits information to the base station, intermediate node, support node, or other node by backscattering modulation of the RF signal received from the base station, intermediate node, support node, or other node by switching the reflection coefficient of its own antenna. For example, the ambient IoT device may transmit information by performing ON-OFF keying.

[0037] For RFID in the 860 MHz-960 MHz band, the reader of the RFID system corresponds to the base station, intermediate node, or support node of the ambient IoT system. The tag corresponds to the ambient IoT device. The RF signal from the reader to the tag is usually a sine wave of a predetermined frequency. ASK (Amplitude Shift Keying) modulation is used for DL ​​information from the reader to the tag. Also, PIE (Pulse Interval Encoding) coding is used for DL ​​information from the reader to the tag. ASK and / or PSK (Phase Shift Keying) modulation is used for UL backscattering. Also, FM0 coding and Miller coding are used for UL backscattering.

[0038] Additionally, the following device types may be defined:

[0039] Device 1) A device with a maximum power consumption of 1 μW or less, with energy storage and no DL or UL amplifiers. UL transmission is performed by backscattering an externally supplied carrier wave.

[0040] Device 2a) A device with a maximum power consumption of a few hundred μW or less, with power storage and with DL and / or UL amplifiers. UL transmission is performed by backscattering an externally supplied carrier wave.

[0041] Device 2b) A device with a maximum power consumption of a few hundred μW or less, with power storage and with DL and / or UL amplifiers, where the UL transmission is generated internally within the device.

[0042] Fig. 5 is a diagram showing an example (1) of an architecture according to an embodiment of the present invention. Fig. 6 is a diagram showing an example (2) of an architecture according to an embodiment of the present invention. Figs. 5 and 6 show examples of defining an architecture in which Topology 1 and Topology 2 are common. In Figs. 5 and 6, a BS or an intermediate node (e.g., a UE) has an internal reader function node, which functions as a reader. In addition to this node, the BS and UE also have an internal RAN function node. The RAN function node performs communication with a CN or a BS.

[0043] Here, the four-step A-IoT random access procedure may be defined as shown in 1)-5) below. Hereinafter, an A-IoT device will also be referred to as a device, and an A-IoT reader will also be referred to as a reader.

[0044] 1) Via A-IoT Msg1, the device sends its ID to the reader. For example, the ID may be randomly generated or generated based on the device ID. 2) Via A-IoT Msg2, the reader may send back to the device the ID received in Msg1. Further information may be included in Msg2. 3) Via A-IoT Msg3, the device sends its device ID and / or other upper layer data to the reader. 4) If Msg2 contains the same random ID as the one included in Msg1, the device may recognize that contention resolution is successful. The size of the random ID may be sufficient for contention resolution purposes. 5) Msg4 does not necessarily have to be sent. Msg4 may be used when Msg3 transmission fails.

[0045] A two-step A-IoT random access procedure may be defined as shown in 1) and 2) below.

[0046] 1) Via A-IoT Msg1, the device sends its device ID and / or other upper layer data to the reader. 2) Via A-IoT Msg2, the reader may send back the information contained in Msg1.

[0047] Contention-free access may also be introduced into the A-IoT random access procedure.

[0048] 7 is a sequence diagram illustrating an example (1) of a random access procedure according to an embodiment of the present invention. This figure shows an example in which four-step random access is applied to an A-IoT random access procedure. As shown in FIG. 7, the A-IoT reader may be a BS or a UE, which is an intermediate node. When an intermediate node is used, communication between the intermediate node and the CN may be performed via the BS.

[0049] Step 1: The CN sends a new NG-AP message to the A-IoT leader. The NG-AP message may specify the target device ID or device group ID, whether location information is required, etc.

[0050] Step 2: The A-IoT reader sends an A-IoT paging message to the A-IoT device. The A-IoT paging message may include the target device ID or device group ID, whether location information is required, etc.

[0051] Step 3: The A-IoT device sends Msg1 for 4-step random access to the A-IoT reader. This Msg1 may include a random ID. The A-IoT device may randomly select any resource to send this Msg1. The resource may be, for example, a time slot or may be specified in the frequency domain.

[0052] Step 4: The A-IoT reader sends Msg2 for 4-step random access to the A-IoT device. Msg2 may include the random ID included in Msg1.

[0053] Step 5: The A-IoT device sends Msg 3 for 4-step random access to the A-IoT reader, which may include the device ID or other information.

[0054] Step 6: The A-IoT reader sends Msg 3 for 4-step random access to the CN, which may include the device ID or other information.

[0055] As shown in FIG. 7, steps 3 to 6 correspond to four-step random access.

[0056] 8 is a sequence diagram illustrating an example (2) of a random access procedure according to an embodiment of the present invention. This figure illustrates an example in which 2-step contention-based random access (CBRA) is applied to an A-IoT random access procedure. As shown in FIG. 8, the A-IoT leader may be a BS or a UE, which is an intermediate node. When an intermediate node is used, communication between the intermediate node and the CN may be performed via the BS.

[0057] Step 1: The CN sends a new NG-AP message to the A-IoT leader. The NG-AP message may specify the target device ID or device group ID, whether location information is required, etc.

[0058] Step 2: The A-IoT reader sends an A-IoT paging message to the A-IoT device. The A-IoT paging message may include the target device ID or device group ID, whether location information is required, etc.

[0059] Step 3: The A-IoT device sends Msg1 for two-step contention-based random access to the A-IoT reader. This Msg1 may include a device ID or other information. The A-IoT device may randomly select any resource to send this Msg1. The resource may be, for example, a time slot or may be specified in the frequency domain.

[0060] Step 4: The A-IoT leader sends Msg1 for two-step contention-based random access to the CN, which may include the device ID or other information.

[0061] Step 4': The A-IoT reader sends Msg2 for two-step contention-based random access to the A-IoT device. Msg2 may be a reply to the content of the received Msg1.

[0062] As shown in FIG. 8, steps 3 to 4 correspond to two-step contention-based random access.

[0063] 9 is a sequence diagram illustrating an example (3) of a random access procedure according to an embodiment of the present invention. FIG. 9 illustrates an example in which 2-step contention-free random access (CFRA) is applied to an A-IoT random access procedure. As shown in FIG. 9, the A-IoT leader may be a BS or a UE, which is an intermediate node. When an intermediate node is used, communication between the intermediate node and the CN may be performed via the BS.

[0064] Step 1: The CN sends a new NG-AP message to the A-IoT leader. The NG-AP message may specify the target device ID or device group ID, whether location information is required, etc.

[0065] Step 2: The A-IoT reader sends an A-IoT paging message to the A-IoT device. The A-IoT paging message may include the target device ID or device group ID, whether location information is required, etc.

[0066] Step 3: The A-IoT device sends Msg1 for two-step contention-free random access to the A-IoT reader. This Msg1 may include a device ID or other information. The A-IoT device may send this Msg1 using a pre-configured resource. The resource may be, for example, a time slot or may be specified in the frequency domain.

[0067] Step 4: The A-IoT leader sends Msg1 for two-step contention-free random access to the CN, which may include the device ID or other information.

[0068] Step 4': The A-IoT reader sends Msg2 for two-step contention-free random access to the A-IoT device. Msg2 may be a reply to the content of the received Msg1.

[0069] 9, steps 3 and 4 correspond to two-step contention-free random access. Note that two-step contention-free random access may also be called contention-free access.

[0070] Fig. 10 is a diagram for explaining a protocol stack according to an embodiment of the present invention. It has been agreed that RRC, SDAP, PDCP, and RLC layers are not supported in communication between an ambient IoT device and a network. Therefore, as shown in Fig. 10, the following protocol stack is assumed.

[0071] NAS (Non-access stratum) / A-IoT NAS: A layer that transmits control information related to ambient IoT devices. It may be assumed to support end-to-end security protection. Note that "NAS / A-IoT NAS" may also mean "NAS or A-IoT NAS."

[0072] MAC / A-IoT MAC: Supports A-IoT random access procedures. May also support other functions, such as BSR and SR-like functions. Note that "MAC / A-IoT MAC" may also mean "MAC or A-IoT MAC."

[0073] PHY / A-IoT PHY: Supports physical channels (PDRSH, PRDSH) specific to the A-IoT system. Other required physical layer protocols may also be supported. Note that "PHY / A-IoT PHY" may also mean "PHY or A-IoT PHY."

[0074] 11 is a sequence diagram illustrating an example (4) of a random access procedure according to an embodiment of the present invention. When an ambient IoT reader attempts two-step CBRA with an ambient IoT device, as in Case 1 shown in FIG. 11, the reader may receive Msg1 and complete collision resolution, but the CN may not be able to decode the NAS / A-IoT NAS message. In this case, it is desirable to have the ambient IoT device retransmit only the NAS / A-IoT NAS message.

[0075] Furthermore, when an ambient IoT reader attempts a two-step CBRA with an ambient IoT device, the ambient IoT reader may not be able to recognize Msg1 at all, resulting in failure of collision resolution and NAS / A-IoT NAS message reception, as in Case 2 shown in Figure 11. In this case, it is desirable to attempt a four-step random access procedure, taking into account the possibility that the wireless environment may be deteriorating.

[0076] 12 is a sequence diagram illustrating an example (5) of a random access procedure according to an embodiment of the present invention. When an ambient IoT reader attempts contention-free access to an ambient IoT device, as in Case 1 shown in FIG. 12, the reader may successfully receive Msg1, but the CN may not be able to decode the NAS / A-IoT NAS message. In this case, the radio resources used by the ambient IoT device to transmit Msg1 during this contention-free access are no longer available, so the random access procedure must be restarted from the beginning. In this case, considering the possibility that the radio environment may have deteriorated, it is desirable to attempt a four-step random access procedure.

[0077] Furthermore, when an ambient IoT reader attempts contention-free access to an ambient IoT device, the ambient IoT reader may not be able to recognize Msg1 at all, resulting in failure to receive the NAS / A-IoT NAS message, as in Case 2 shown in Figure 12. In this case, it is desirable to attempt a four-step random access procedure, taking into consideration the possibility that the wireless environment may be deteriorating.

[0078] 13 is a sequence diagram illustrating an example (6) of a random access procedure according to an embodiment of the present invention. As shown in FIG. 13, if the CN fails to decode the message in STEP 4 of the two-step CBRA, it may execute STEPs 5 to 8.

[0079] When the CN fails to decode the NAS / A-IoT NAS message received from the ambient IoT device, the CN may notify the ambient IoT reader of the failure to decode (STEP 5). The notification may include the device ID.

[0080] When the ambient IoT reader receives a notification from the CN that it has failed to decode the NAS / A-IoT NAS message for an ambient IoT device for which it has instructed 2-step CBRA, it may send a message to the ambient IoT device instructing it to fall back to 4-step CBRA (STEP 6).

[0081] When the ambient IoT device receives a message from the ambient IoT reader instructing it to fall back to four-step CBRA, it may send msg 3 of the four-step CBRA, i.e., a NAS / A-IoT NAS message (STEP 7 and STEP 8).

[0082] The ambient IoT reader may notify the ambient IoT device of radio resource information for transmitting Msg3 when the ambient IoT device falls back to 4-step CBRA via an A-IoT paging message (STEP 2), or may notify the ambient IoT device of radio resource information for transmitting Msg3 when the ambient IoT device falls back to 4-step CBRA via a message instructing the ambient IoT device to fall back to 4-step CBRA (STEP 6).

[0083] An ambient IoT device may report to the network via a device capability message that it supports the ability to fall back to 4-step CBRA or 4-step RA while performing 2-step CBRA.

[0084] 14 is a sequence diagram illustrating an example (7) of a random access procedure according to an embodiment of the present invention. As shown in FIG. 14, the ambient IoT reader may manage the following timers:

[0085] Start: When an A-IoT paging message instructing the triggering of a two-step CBRA or contention-free access is sent. Stop: When Msg1 is received from the ambient IoT device. Ambient IoT reader operation upon expiration: Send an A-IoT paging message instructing a four-step CBRA.

[0086] When the ambient IoT device receives the A-IoT paging message with the timer expiring, it may perform the normal four-step random access procedure.

[0087] 15 is a sequence diagram illustrating an example (8) of a random access procedure according to an embodiment of the present invention. As shown in FIG. 15, when the CN completes decoding of the NAS / A-IoT NAS message, the CN may notify the ambient IoT reader of the successful decoding (STEP 5). The notification may include the device ID of the ambient IoT device that sent the message.

[0088] As shown in FIG. 15, the ambient IoT reader may manage the following timers:

[0089] Start: When an A-IoT paging message instructing a two-step CBRA or contention-free access trigger is sent. Stop: When a notification is received from the CN informing that the decoding of the NAS / A-IoT NAS message sent by the ambient IoT device has been completed. Ambient IoT reader operation upon expiration: Sends an A-IoT paging message instructing a four-step CBRA.

[0090] When the ambient IoT device receives the A-IoT paging message with the timer expiring, it may perform the normal four-step random access procedure.

[0091] 16 is a sequence diagram illustrating an example (9) of a random access procedure according to an embodiment of the present invention. As shown in FIG. 16, the ambient IoT reader may notify the D2R radio resource information for transmitting Msg1 of the 4-step CBRA via an A-IoT paging message instructing the 2-step CBRA or contention-free access (STEP 2).

[0092] As shown in FIG. 16, the ambient IoT device may manage timers such as:

[0093] Start: When Msg 1 for 2-step CBRA or contention-free access is transmitted. Stop: When a message for 2-step CBRA completion notification or contention-free access completion notification is received from the ambient IoT reader. Operation of the ambient IoT device at expiration: Transmits Msg 1 for 4-step CBRA based on the D2R radio resource information notified via the A-IoT paging message.

[0094] When the CN successfully decodes the NAS / A-IoT NAS message received from the ambient IoT device, the CN may notify the ambient IoT reader of the successful decoding (STEP 5). The notification may include the device ID.

[0095] When the ambient IoT reader receives notification from the CN that the NAS / A-IoT NAS message has been successfully decoded for an ambient IoT device that has instructed two-step CBRA or contention-free access, the ambient IoT reader may send a message to the ambient IoT device notifying it that two-step CBRA or contention-free access has been completed (STEP 6).

[0096] The ambient IoT device may report to the network via a device capability message that it supports the ability to fall back to a four-step RA and send Msg1 upon timer expiration.

[0097] As described above, in an ambient IoT system, it becomes possible to dynamically select a random access procedure that takes into account the wireless environment.

[0098] In other words, the reliability of the random access procedure of ambient Internet of Things (IoT) devices can be improved.

[0099] (Device Configuration) Next, a functional configuration example of the base station 10 and the terminal 20 that execute the processes and operations described above will be described. The base station 10 and the terminal 20 include functions for implementing the above-described embodiments. However, the base station 10 and the terminal 20 may each include only a part of the functions of the embodiments.

[0100] <Base Station 10> Figure 17 is a diagram showing an example of the functional configuration of the base station 10 in the embodiment of the present invention. As shown in Figure 17, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Figure 17 is merely an example. The names of the functional divisions and functional units may be any names as long as they can perform the operations related to the embodiment of the present invention.

[0101] The transmitter 110 has a function of generating a signal to be transmitted to the terminal 20 side and transmitting the signal wirelessly. The transmitter 110 also transmits inter-network node messages to other network nodes. The receiver 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of higher layers from the received signals. The transmitter 110 also has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, etc. to the terminal 20. The receiver 120 also receives inter-network node messages from other network nodes.

[0102] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20. The content of the setting information is, for example, information related to communication with an ambient IoT device.

[0103] The control unit 140 performs control to realize the functions described in the embodiments. Furthermore, as described in the embodiments, the control unit 140 performs control related to communication with the ambient IoT device. A functional unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and a functional unit related to signal reception in the control unit 140 may be included in the receiving unit 120.

[0104] <Terminal 20> Fig. 18 is a diagram showing an example of the functional configuration of terminal 20 in an embodiment of the present invention. As shown in Fig. 18, terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 18 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations related to the embodiment of the present invention.

[0105] The transmitter 210 creates a transmission signal from transmission data and transmits the transmission signal wirelessly. The receiver 220 wirelessly receives various signals and acquires higher layer signals from the received physical layer signals. The receiver 220 also has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals, and the like transmitted from the base station 10. For example, the transmitter 210 transmits a PSCCH (Physical Sidelink Control Channel), a PSSCH (Physical Sidelink Shared Channel), a PSDCH (Physical Sidelink Discovery Channel), a PSBCH (Physical Sidelink Broadcast Channel), and the like to another terminal 20 as D2D communication, and the receiver 220 receives the PSCCH, PSSCH, PSDCH, or PSBCH, and the like, from the other terminal 20.

[0106] The setting unit 230 stores various setting information received from the base station 10 by the receiving unit 220. The setting unit 230 also stores setting information that is set in advance. The content of the setting information is, for example, information related to communication with an ambient IoT device.

[0107] The control unit 240 performs control to realize the functions described in the embodiments. Furthermore, as described in the embodiments, the control unit 240 performs control related to communication with the ambient IoT device. A functional unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and a functional unit related to signal reception in the control unit 240 may be included in the receiving unit 220.

[0108] (Hardware Configuration) The block diagrams (FIGS. 17 and 18) 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 (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or the multiple devices.

[0109] Functions include, but are not limited to, judgment, determination, judgment, 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.

[0110] For example, the base station 10, the terminal 20, etc. 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. 19 is a diagram illustrating an example of the hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The base station 10 and the terminal 20 described above may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0111] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 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.

[0112] Each function in the base station 10 and the terminal 20 is realized by loading specified software (programs) onto hardware such as the processor 1001, the memory device 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls at least one of reading and writing data in the memory device 1002 and the auxiliary memory device 1003.

[0113] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as 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 140, control unit 240, etc. may be realized by the processor 1001.

[0114] Furthermore, the processor 1001 reads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002 and executes various processes in accordance with the programs. 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 140 of the base station 10 shown in FIG. 17 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. Furthermore, for example, the control unit 240 of the terminal 20 shown in FIG. 18 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. 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.

[0115] The storage device 1002 is a computer-readable recording medium and may be configured, for example, by at least one of a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory, etc. The storage device 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0116] The secondary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of 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. The above-mentioned storage medium may be, for example, a database, a server, or other appropriate medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0117] 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, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated.

[0118] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts 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. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0119] Furthermore, each device such as the processor 1001 and the storage device 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.

[0120] Furthermore, the base station 10 and the terminal 20 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, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0121] Fig. 20 shows an example configuration of a vehicle 2001. As shown in Fig. 20, 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.

[0122] 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.

[0123] 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).

[0124] 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 front or rear wheel rotation speed signal obtained by a rotation speed sensor 2022, a front or rear wheel air pressure signal 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.

[0125] 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 for controlling these devices. The information service unit 2012 uses information acquired from external devices via the communication module 2013 or the like to provide various types of multimedia information and multimedia services to the occupants of the vehicle 2001. The information service unit 2012 may include input devices (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, a touch panel, etc.) that accept input from the outside, and may also include output devices (e.g., a display, a speaker, an LED lamp, a touch panel, etc.) that output information to the outside.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] The communication module 2013 may transmit at least one of signals from the above-mentioned various sensors 2021-2028 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 2021-2028, 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.

[0130] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may 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 (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the 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, axles 2009, sensors 2021 to 2029, etc. provided in the vehicle 2001.

[0131] (Summary of Embodiments) As described above, according to the embodiments of the present invention, there is provided a communications device including: a receiver that receives a paging message from an ambient Internet of Things (IoT) reader; and a controller that executes a two-step contention-based random access procedure or a contention-free random access procedure with the ambient IoT reader based on the paging message, wherein the receiver receives a message from the ambient IoT reader instructing a fallback to a four-step contention-based random access procedure, and the controller executes the four-step contention-based random access procedure with the ambient IoT reader.

[0132] The above configuration enables an ambient IoT system to dynamically select a random access procedure that takes into account the wireless environment, thereby improving the reliability of the random access procedure of ambient IoT (Internet of Things) devices.

[0133] The device may further include a transmitter that, when the receiver receives a message from the ambient IoT reader instructing the device to fall back to the four-step contention-based random access procedure, transmits Msg3 in the four-step contention-based random access procedure to the ambient IoT reader. This configuration enables the ambient IoT system to dynamically select a random access procedure that takes into account the wireless environment.

[0134] The device may further include a transmitter that transmits a Msg1 in the four-step contention-based random access procedure to the ambient IoT reader when the receiver receives a message instructing the ambient IoT reader to fall back to the four-step contention-based random access procedure from the ambient IoT reader. This configuration enables the ambient IoT system to dynamically select a random access procedure taking into account the wireless environment.

[0135] The control unit may start a timer when transmitting Msg1 in a two-step contention-based random access procedure or a contention-free random access procedure, and may stop the timer when the receiving unit receives a notification of completion of the two-step contention-based random access procedure or the contention-free random access procedure. With this configuration, it becomes possible to dynamically select a random access procedure taking into account the wireless environment in an ambient IoT system.

[0136] The control unit may further include a transmitter that starts a timer when transmitting Msg1 in the two-step contention-based random access procedure or the contention-free random access procedure, and transmits Msg1 in the four-step contention-based random access procedure to the ambient IoT reader when the timer expires. This configuration enables the ambient IoT system to dynamically select a random access procedure taking into account the wireless environment.

[0137] Also, according to an embodiment of the present invention, there is provided a communication method in which a communication device performs the following procedures: receiving a paging message from an ambient Internet of Things (IoT) reader; performing a two-step contention-based random access procedure or a contention-free random access procedure with the ambient IoT reader based on the paging message; receiving a message from the ambient IoT reader instructing a fallback to a four-step contention-based random access procedure; and performing the four-step contention-based random access procedure with the ambient IoT reader.

[0138] The above configuration enables an ambient IoT system to dynamically select a random access procedure that takes into account the wireless environment, thereby improving the reliability of the random access procedure of ambient IoT (Internet of Things) devices.

[0139] (Supplementary Notes on the Embodiments) Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention; matters described in two or more items may be used in combination as needed, and matters described in one item may apply to matters described in another item (as long as there is no contradiction). Boundaries between functional units or processing units in functional block diagrams do not necessarily correspond to boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the base station 10 and terminal 20 have been described using functional block diagrams, but such devices may be realized by hardware, software, or a combination thereof. The software operated by the processor of the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

[0140] Furthermore, the 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 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, the 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.

[0141] Each aspect / embodiment described in the present disclosure may be implemented using any of the following standards: 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 number)), 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 ( 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).

[0142] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein may be rearranged unless it is consistent. 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.

[0143] In this specification, a specific operation described as being performed by the base station 10 may be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and another network node other than the base station 10 (such as, but not limited to, an MME or an S-GW). Although the above example illustrates a case where there is one other network node other than the base station 10, the other network node may be a combination of multiple other network nodes (such as an MME and an S-GW).

[0144] The information, signals, etc. described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0145] Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be transmitted to another device.

[0146] In the present disclosure, the determination may be made by a value represented by one bit (0 or 1), by a Boolean value (true or false), or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0147] 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.

[0148] 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.

[0149] 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 be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0150] 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.

[0151] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0152] Furthermore, 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. For example, a radio resource may be indicated by an index.

[0153] 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.

[0154] In the present disclosure, terms such as "base station (BS)," "radio base station," "base station device," "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.

[0155] 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 small indoor base station (RRH: Remote Radio Head)). The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage.

[0156] 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.

[0157] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," and the like may be used interchangeably.

[0158] 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.

[0159] 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 a mobile object that moves autonomously 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.

[0160] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple terminals 20 (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0161] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station may be configured to have the functions of the user terminal described above.

[0162] 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 in a table, database, or other data structure), ascertaining, 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. 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.

[0163] 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.

[0164] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0165] 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."

[0166] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. 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 in some way precede the second element.

[0167] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0168] 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.

[0169] 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.

[0170] Numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as 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, specific windowing operations performed by the transceiver in the time domain, etc.

[0171] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may be a time unit based on numerology.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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 wireless resources (such as frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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 the numerology, for example, 12. The number of subcarriers included in an RB may be determined based on the numerology.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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."

[0187] 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.

[0188] 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 in the plural form.

[0189] 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 "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0190] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0191] 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.

[0192] REFERENCE SIGNS LIST 10 Base station 110 Transmitter 120 Receiver 130 Setting unit 140 Control unit 20 Terminal 210 Transmitter 220 Receiver 230 Setting unit 240 Control unit 30 Core network 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Front wheels 2008 Rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 RPM sensor 2023 Tire pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driving assistance system unit 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port (IO port)

Claims

1. A communications device comprising: a receiver that receives a paging message from an ambient IoT (Internet of Things) reader; and a controller that executes a two-step contention-based random access procedure or a contention-free random access procedure with the ambient IoT reader based on the paging message, wherein the receiver receives a message from the ambient IoT reader instructing a fallback to a four-step contention-based random access procedure, and the controller executes the four-step contention-based random access procedure with the ambient IoT reader.

2. The communication device of claim 1, further comprising a transmitter that transmits Msg3 in the four-step contention-based random access procedure to the ambient IoT reader when the receiver receives a message from the ambient IoT reader instructing fallback to the four-step contention-based random access procedure.

3. The communication device of claim 1, further comprising a transmitter that transmits Msg1 in the four-step contention-based random access procedure to the ambient IoT reader when the receiver receives a message from the ambient IoT reader instructing fallback to the four-step contention-based random access procedure.

4. The communication device of claim 1, wherein the control unit starts a timer when it transmits Msg1 in a two-step contention-based random access procedure or a contention-free random access procedure, and the control unit stops the timer when the receiving unit receives a notification of completion of the two-step contention-based random access procedure or the contention-free random access procedure.

5. The communication device of claim 1, further comprising a transmitting unit that starts a timer when the control unit transmits Msg1 in a two-step contention-based random access procedure or a contention-free random access procedure, and transmits Msg1 in a four-step contention-based random access procedure to the ambient IoT reader when the timer expires.

6. A communication method in which a communication device performs the following steps: receiving a paging message from an ambient Internet of Things (IoT) reader; executing a two-step contention-based random access procedure or a contention-free random access procedure with the ambient IoT reader based on the paging message; receiving a message from the ambient IoT reader instructing a fallback to a four-step contention-based random access procedure; and executing a four-step contention-based random access procedure with the ambient IoT reader.

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