Ambient IoT device, reader, and methods thereof

Abstract

An Ambient Internet of Things (AIoT) device receives a first reader-to-device (R2D) message. The AIoT device transmits a device-to-reader (D2R) message in response to the first R2D message. The size of the D2R message, the length of a Protocol Data Unit (PDU) containing the D2R message, the length of a physical channel carrying the D2R message, the length of transmission duration of the physical channel, and the length of an access occasion over which the physical channel is transmitted are predefined fixed values. This contributes to solving problems related to supporting AIoT devices in cellular networks, for example.

Description

Ambient IoT Devices, Readers, and Methods Thereof

[0001] The present disclosure relates to wireless communication systems in which Ambient Internet of Things (AIoT) devices are used.

[0002] The 3rd Generation Partnership Project (3GPP (registered trademark)) is considering supporting AIoT devices in 5G NR for Release 19 and beyond (see, for example, non-patent documents 1-5). AIoT devices are ambient power-enabled IoT devices. AIoT devices are IoT devices that are powered by energy harvesting and are battery-less or have limited energy storage capabilities (e.g., using capacitors). Energy for AIoT devices is supplied by harvesting radio waves, light, motion, heat, or other suitable power sources.

[0003] AIoT device types may be distinguished by the presence or absence of power storage capabilities. Additionally or alternatively, AIoT device types may be distinguished by the magnitude of their peak power consumption. Additionally or alternatively, AIoT device types may be distinguished by whether they have uplink amplification and / or downlink amplification. Additionally or alternatively, AIoT device types may be distinguished by whether the device's uplink transmission is a backscatter transmission on an externally supplied carrier or is generated by the device's active Radio Frequency (RF) components.

[0004] Non-Patent Document 2 discloses roughly four connectivity topologies for AIoT devices, as follows: Topology 1 is direct communication between a base station and an AIoT device. In Topology 1, the AIoT device communicates directly and bidirectionally with the base station. The communication between the base station and the AIoT device includes one or both of AIoT data and signaling. Topology 1 includes the possibility that the base station transmitting to the AIoT device and the base station receiving from the AIoT device may be different.

[0005] Topology 2 is communication between a base station and an AIoT device via an intermediate node. In Topology 2, the AIoT device communicates bidirectionally with the intermediate node located between the device and the base station. The intermediate node can be a relay, Integrated Access and Backhaul (IAB) node, User Equipment (UE), or repeater, which are compatible with Ambient IoT. The intermediate node transfers AIoT data and / or signaling between the base station and the AIoT device.

[0006] Topology 3 is communication between a base station and an AIoT device via an assisting node. Topology 3 includes an option where the assisting node assists the downlink (Topology 3 with downlink assistance) and an option where the assisting node assists the uplink (Topology 3 with uplink assistance). In Topology 3 with downlink assistance, the AIoT device transmits data and / or signaling to the base station and receives data and / or signaling from the assisting node. In Topology 3 with uplink assistance, the AIoT device receives data and / or signaling from the base station and transmits data and / or signaling to the assisting node. The assisting node is a relay, IAB node, UE, repeater, etc. that supports ambient IoT.

[0007] Topology 4 is direct communication between the UE and the AIoT device. In Topology 4, the AIoT device communicates bidirectionally with the UE. The communication between the UE and the AIoT device includes AIoT data and / or signaling.

[0008] Non-Patent Document 1 presents a study item on solutions for AIoT in NR. The overall objective of this study item is to consider a harmonized air interface design for AIoT with minimized differences (if necessary) to enable the following two types of devices: The first type of AIoT device has a peak power consumption of approximately 1 μW or less, has energy storage, and does not have downlink or uplink amplification within the device. The uplink transmission of the first type of AIoT device is backscattered on an externally supplied carrier. The second type of AIoT device has a power consumption of several hundred μW or less, has energy storage, and has one or both downlink and uplink amplification. The uplink transmission of the second type of AIoT device is backscattered transmission on an externally supplied carrier or is generated by active RF components within the device.

[0009] The general scope of the study item defined in Non-Patent Document 1 assumes no Radio Resource Control (RRC) state, no mobility (i.e., at least no cell selection / re-selection-like functions), no Hybrid Automatic Repeat Request (HARQ), and no ARQ. In addition, the general scope of the study item targets Topology 1 and Topology 2 among the connection topologies described in Non-Patent Document 2, and assumes a UE as an intermediate node in Topology 2.

[0010] Section 8.2 of Non-Patent Document 4 describes the discussions and agreements regarding Ambient IoT at the 126th meeting of the 3GPP Technical Specification Group (TSG) Radio Access Network (RAN) Working Group #2 (WG2) (RAN2). Section 8.2.2 of Non-Patent Document 4 describes the following agreements regarding Stage 2 general aspects, particularly regarding the three cases of "inventory only," "command only," and "inventory and command."

[0011] As a baseline, the "inventory only" case is supported by the following steps: Step A: AIoT Paging; and Step B: Device ID transmission (via random access (RA) or without RA). Details of Step B will be discussed further.

[0012] As a baseline, the "inventory and command" case is supported by the following steps: Step A: AIoT paging; Step B: Device ID transmission (via random access (RA) or without RA); Step C: Reader to device (R2D) data transmission (e.g., R2D command); and Step D: Supported device to reader (D2R) data transmission (e.g., feedback). Whether Step D is optional is left for discussion in other WGs.

[0013] "Inventory and command" does not mean that AIoT paging includes both inventory and command in the same message. "Inventory and command" does not mean that inventory and command are received by the reader from upper layers at the same time.

[0014] RAN2 considers a "command only" use case. Options to support this will be further explored. In the "command only" use case, the initial trigger message from the reader is expected to contain the command, but the ultimate feasibility of this will depend on the work and conclusions of 3GPP TSG Service and System Aspects (SA) WG #2 (SA2) and WG #3 (SA3). The "command only" use case will use the "inventory and command" baseline procedure (i.e., first trigger the inventory procedure, then send the command).

[0015] Section 8.2.3 of Non-Patent Document 4 states the following agreement regarding functionality aspects:

[0016] Multiple AIoT logical channels for upper layer data are not supported. Whether the concept of AIoT logical channels will be used is further discussed and depends on the final modeling issue.

[0017] Neither the legacy NR Buffer Status Report (BSR) nor the Scheduling Request (SR) are required for AIoT communication. Whether additional indications regarding the size or status of device messages (i.e., D2R messages) are needed will be discussed further.

[0018] Access Stratum (AS) Radio Link Control (RLC)-like retransmissions or repetitions (above the physical layer) are not supported. This does not preclude readers and AIoT devices from retransmitting the payload as a new transmission from a Medium Access Control (MAC) perspective. How to handle segmentation cases will be discussed further if necessary.

[0019] Section 8.2.4 of Non-Patent Document 4 describes the following agreements regarding AIoT paging:

[0020] RAN2 considers the following cases for AIoT paging messages: - A message containing the ID of a single AIoT device; - A message containing a group ID corresponding to multiple AIoT devices; - A message without an ID, i.e., a message targeted at all devices that can receive AIoT messages; - A message containing multiple IDs of multiple AIoT devices.

[0021] Based on the discussion in SA2, the need for use cases of messages containing multiple IDs of multiple AIoT devices needs to be confirmed. What the device IDs, group IDs, and scenarios are depends on the discussion in SA2.

[0022] The AIoT paging message indicates information that allows the device to decide which resources to use for the response (D2R message). How (e.g., implicit / explicit / configured / preconfigured) and what resources (dedicated and / or shared) are provided to the device will be further considered in light of the discussions in 3GPP TSG RAN WG #1 (WG1) (RAN1).

[0023] From the perspective of RAN2, it is assumed that AIoT devices will be able to receive as long as there is sufficient energy. For details on device monitoring, we will await future progress on RAN1.

[0024] Section 8.2.5 of Non-Patent Document 4 describes the following agreements regarding AIoT random access (RA):

[0025] The four-step RA agreement includes the following: In the first AIoT RA message (Msg1), the device sends its ID to the reader. This ID is a random ID generated by the device. How the ID is generated, for example, whether it is randomly generated or generated based on the device ID, is further discussed. This does not exclude other RAN1 agreed information. In the second AIoT RA message (Msg2), the reader echoes the ID received in Msg1. Based on the RAN1 agreement, further information may be included in Msg2. In the third AIoT RA message (Msg3), the device sends its device ID and / or other upper layer data (depending on the upper layer requirements). If the device receives Msg2 containing the same random ID as Msg1, it considers the conflict resolution successful. RAN2 assumes that the size of the random ID in Msg1 is sufficient for conflict resolution purposes. The "fourth message (Msg4)" (i.e., the subsequent R2D transmission after a D2R transmission) does not necessarily have to be transmitted in random access. Msg4 can be considered to handle the failure of Msg3 transmission (due to various reasons). The use and existence of Msg4 can be further discussed. In RAN2, the term "Msg4" is not used in further discussions of random access.

[0026] Agreement on a two-step RA includes the following: In AIoT RA Msg1, the device sends the device ID and / or other upper layer data (depending on the upper layer requirements). What the device ID is and whether an additional random ID is required will be confirmed in further discussion. This does not exclude other RAN1 agreed information. In AIoT RA Msg2, the leader may echo some information from Msg1. What that information is, as well as the use and existence of Msg2, can be further discussed.

[0027] Section 8.2 of Non-Patent Document 5 describes the discussions and agreements regarding Ambient IoT at the 125bis meeting of 3GPP RAN2. Section 8.2.5 of Non-Patent Document 5 describes the following agreements regarding AIoT RA: RAN2 confirmed that the baseline for AIoT random access is slotted ALOHA. RAN2 considers support for access triggers for a single device, a group of devices, or all devices. RAN2 considers contention-based and contention-free access procedures and detailed solutions. Random access is triggered by the leader.

[0028] As can be understood from the above-mentioned RAN2 agreement on AIoT RA, an AIoT 4-step RA may not use Msg4 and may therefore actually consist of three steps (i.e., Msg1, Msg2, and Msg3 transmissions). Similarly, an AIoT 2-step RA may not use Msg2 and may therefore actually consist of only one step (i.e., Msg1 transmission). Taking these factors into consideration, the terms "4-step-like random access (procedure)" and "2-step-like random access (procedure)" are used herein. The term "4-step-like random access (procedure)" refers to a first type of AIoT RA procedure that may not use Msg4 and may therefore actually consist of three steps (i.e., Msg1, Msg2, and Msg3 transmissions). In other words, the term "4-step-like random access (procedure)" may refer to a 3-step RA or a 4-step RA. The term "two-step-like random access" refers to a second type of AIoT RA procedure that may not use Msg2 and therefore may actually consist of only one step (i.e., Msg1 transmission). In other words, the term "two-step-like random access" may refer to a one-step RA or a two-step RA.

[0029] Huawei, "New SID: Study on solutions for Ambient IoT (Internet of Things) in NR", RP-234058, 3GPP TSG RAN Meeting #102, Edinburgh, UK, December 11-15, 20233GPP TR 38.848 V18.0.0 (2023-09) "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on Ambient IoT (Internet of Things) in RAN (Release 18)", September 20233GPP TR 22.840 V19.0.0 (2023-12) "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Study on Ambient power-enabled Internet of Things (Release 19)", December 2023ETSI MCC, "Report of 3GPP TSG RAN WG2 meeting #126, Fukuoka, Japan", [online], [retrieved on 2024-7-28], Retrieved from the Internet: <URL: https: / / www.3gpp.org / ftp / TSG_RAN / WG2_RL2 / TSGR2_126 / Report / Draft_R2_126_Meeting_Report_v2.zip>ETSI MCC, "Report of 3GPP TSG RAN WG2 meeting #125bis, Changsha, China", R2-2404102, 3GPP TSG-RAN WG2 meeting #126, May 2024

[0030] The inventors have investigated communication between AIoT devices and a reader and found various issues. Here, the reader is a base station in the case of Topology 1, an intermediate node in the case of Topology 2, one or a combination of a base station and an assist node in the case of Topology 3, and a UE in the case of Topology 4.

[0031] Some of these challenges relate to the content and / or format of R2D messages sent from readers to AIoT devices. At present, it is not fully clear what content an R2D message should contain and how the format of the R2D message should be defined.

[0032] Some of the other challenges relate to random access using slotted ALOHA. As mentioned above, 3GPP RAN2 has confirmed that the baseline for AIoT random access is slotted ALOHA. However, when slotted ALOHA is used for D2R transmissions (e.g., RA Msg1 transmissions), it is not fully clear how to trigger D2R transmissions at each access occasion (or slot).

[0033] One of the objectives of the embodiments disclosed herein is to provide an apparatus, a method, and a program that contribute to solving at least one of the problems related to communication between an AIoT device and a reader, including the problems described above. It should be noted that this objective is only one of the objectives of the embodiments disclosed herein. Other objectives or objectives and novel features will become apparent from the description of this specification or the accompanying drawings.

[0034] In a first aspect, an AIoT device is configured to receive a first R2D message and transmit a D2R message in response to the first R2D message, wherein the size of the D2R message, the length of a Protocol Data Unit (PDU) containing the D2R message, the length of a physical channel carrying the D2R message, the length of a transmission duration of the physical channel, or the length of an access occasion on which the physical channel is transmitted are predefined fixed values.

[0035] In a second aspect, a method performed by an AIoT device includes (a) receiving a first R2D message, and (b) transmitting a D2R message in response to the first R2D message, wherein a size of the D2R message, a length of a PDU containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted is a predefined fixed value.

[0036] In a third aspect, a reader is configured to send a first R2D message and receive a D2R message sent by an AIoT device in response to the first R2D message, wherein the size of the D2R message, the length of a PDU containing the D2R message, the length of a physical channel carrying the D2R message, the length of a transmission duration of the physical channel, or the length of an access occasion on which the physical channel is transmitted are predefined fixed values.

[0037] In a fourth aspect, a method performed by a reader includes (a) transmitting a first R2D message, and (b) receiving a D2R message transmitted by an AIoT device in response to the first R2D message, wherein a size of the D2R message, a length of a PDU containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted is a predefined fixed value.

[0038] In a fifth aspect, an AIoT device is configured to receive a first R2D message, the first R2D message including a first field indicating a parameter for specifying a size of a D2R message to be transmitted in response to receiving the first R2D message, a length of a PDU containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion on which the physical channel is transmitted, and the AIoT device is configured to transmit the D2R message according to the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter.

[0039] In a sixth aspect, a method performed by an AIoT device includes: (a) receiving a first R2D message, wherein the first R2D message includes a first field indicating a parameter for specifying a size of a D2R message to be transmitted in response to receiving the first R2D message, a length of a PDU containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted; and (b) transmitting the D2R message in accordance with the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter.

[0040] In a seventh aspect, a reader is configured to transmit a first R2D message, the first R2D message including a first field indicating a parameter for specifying a size of a D2R message to be transmitted in response to receiving the first R2D message, a length of a PDU containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted.

[0041] In an eighth aspect, a method performed by a reader includes transmitting a first R2D message, the first R2D message including a first field indicating parameters for specifying a size of a D2R message to be transmitted in response to receiving the first R2D message, a length of a PDU containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted.

[0042] In a ninth aspect, an AIoT device is configured to receive a first type access occasion initiation message, the first type access occasion initiation message being sent to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, the first type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an AIoT device to respond to the access occasion initiated by the first type access occasion initiation message.

[0043] In a tenth aspect, a method performed by an AIoT device includes receiving a first-type access occasion initiation message, the first-type access occasion initiation message being sent to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, the first-type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first-type access occasion initiation message or a second parameter for specifying an AIoT device to respond to the access occasion initiated by the first-type access occasion initiation message.

[0044] In an eleventh aspect, a reader is configured to transmit a first type access occasion initiation message, the first type access occasion initiation message being transmitted to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, the first type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an AIoT device that should respond to the access occasion initiated by the first type access occasion initiation message.

[0045] In a twelfth aspect, a method performed by a reader includes transmitting a first type access occasion initiation message, the first type access occasion initiation message being transmitted to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, the first type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an AIoT device to respond to the access occasion initiated by the first type access occasion initiation message.

[0046] In a thirteenth aspect, an AIoT device is configured to include or add a predetermined end marker or postamble to a D2R message transmitted in an access occasion, a PDU containing the D2R message, or a physical channel carrying the D2R message if D2R transmission is completed within the access occasion. The AIoT device is configured not to include or add the end marker or postamble to the D2R message, the PDU, or the physical channel if D2R transmission is not completed within the access occasion and there is pending data.

[0047] In a fourteenth aspect, a method performed by an AIoT device includes: (a) if a D2R transmission is completed within an access occasion, including or adding a predetermined end marker or postamble to a D2R message transmitted in the access occasion, a PDU containing the D2R message, or a physical channel carrying the D2R message; and (b) if a D2R transmission is not completed within the access occasion and there is pending data, the AIoT device does not include or add the end marker or postamble to the D2R message, the PDU, or the physical channel.

[0048] In a fifteenth aspect, an AIoT device is configured to receive an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, wherein the access occasion initiation message includes information indicating the order of a current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

[0049] In a sixteenth aspect, a method performed by an AIoT device includes receiving an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, wherein the access occasion initiation message includes information indicating the order of a current access occasion within the plurality of access occasions initiated by the access occasion initiation message.

[0050] In a seventeenth aspect, a reader is configured to transmit an access occasion initiation message to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, the access occasion initiation message including information indicating the order of a current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

[0051] In an eighteenth aspect, a method performed by a reader includes transmitting an access occasion initiation message to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger or paging message, the access occasion initiation message including information indicating the order of a current access occasion within the plurality of access occasions initiated by the access occasion initiation message.

[0052] In a nineteenth aspect, a program includes a group of instructions (software code) that, when loaded into a computer, causes the computer to perform a method according to any of the above aspects.

[0053] According to the above-mentioned aspects, it is possible to provide an apparatus, a method, and a program that contribute to solving at least one of multiple problems related to communication between an AIoT device and a reader, including the problems described above.

[0054]

[0014] Figure 1 illustrates an example connection topology for an AIoT device, which relates to one or more embodiments.

[0015] Figure 2 illustrates an example connection topology for an AIoT device, which relates to one or more embodiments.

[0016] Figure 3 illustrates an example connection topology for an AIoT device, which relates to one or more embodiments.

[0017] Figure 4 illustrates an example connection topology for an AIoT device, which relates to one or more embodiments.

[0018] Figure 5 illustrates an example inventory procedure, which relates to one or more embodiments.

[0019] Figure 6 illustrates an example inventory and command procedure, which relates to one or more embodiments.

[0020] Figure 7 illustrates an example command procedure, which relates to one or more embodiments.

[0021] Figure 8 illustrates an example random access using slotted ALOHA, which relates to one or more embodiments.

[0022] Figure 9 illustrates an example inventory procedure using slotted ALOHA, which relates to one or more embodiments.

[0023] Figure 10 illustrates an example inventory procedure using slotted ALOHA, which relates to one or more embodiments.

[0024] Figure 11 illustrates an example inventory procedure using slotted ALOHA, which relates to one or more embodiments.

[0025] Figure 12 illustrates an example inventory procedure using slotted ALOHA, which relates to one or more embodiments.

[0026] Figure 13 illustrates a flowchart illustrating an example operation of an AIoT device, which relates to one or more embodiments.

[0027] Figure 14 illustrates an example R2D message format, which relates to one or more embodiments. FIG. 1 is a flowchart illustrating an example of an AIoT device operation, in accordance with one or more embodiments; FIG. 2 is a diagram illustrating an example of an R2D message format, in accordance with one or more embodiments; FIG. 3 is a diagram illustrating an example of an AIoT device and reader operation, in accordance with one or more embodiments; FIG. 4 is a flowchart illustrating an example of an AIoT device operation, in accordance with one or more embodiments; FIG. 5 is a flowchart illustrating an example of an AIoT device operation, in accordance with one or more embodiments;

[0014] Figure 1 illustrates an example inventory procedure using slotted ALOHA, in accordance with one or more embodiments.

[0015] Figure 2 illustrates an example flow chart of an AIoT device operation, in accordance with one or more embodiments.

[0016] Figure 3 illustrates an example configuration of an AIoT device, in accordance with one or more embodiments.

[0017] Figure 4 illustrates an example configuration of a base station, in accordance with one or more embodiments.

[0018] Figure 5 illustrates an example configuration of an intermediate node, in accordance with one or more embodiments.

[0055] Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are designated by the same reference numerals, and for clarity of explanation, duplicate explanations will be omitted as necessary.

[0056] The multiple embodiments described below may be used independently, or two or more embodiments may be combined as appropriate. These multiple embodiments may have different novel features. Therefore, these multiple embodiments may contribute to achieving different objectives or solving different problems, and may contribute to achieving different effects.

[0057] Each drawing is merely an example for describing one or more embodiments. Each drawing may not relate to only one particular embodiment, but may also relate to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0058] The following embodiments will be described with a focus on the 3GPP 5th generation mobile communication system (5G system), but may also be applied to other wireless communication systems that support AIoT devices.

[0059] As used herein, depending on the context, "if" may be interpreted to mean "when," "while," "at or around the time," "after," "upon," "in response to determining," "in accordance with a determination," or "in response to detecting." These expressions may be interpreted to have the same meaning, depending on the context.

[0060] First, the configurations and operations of several network elements common to several embodiments will be described. Figures 1 to 4 show several example connection topologies for an AIoT device 1. Each element (network function) shown in Figures 1 to 4 can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform.

[0061] The AIoT device 1 is an ambient power-enabled IoT device. The AIoT device 1 is an IoT device that is powered by energy harvesting and is battery-less or has limited energy storage capability (e.g., using a capacitor). Energy for the AIoT device 1 is supplied by harvesting radio waves, light, motion, heat, or other suitable power sources.

[0062] The types of AIoT devices 1 may be distinguished by whether they have power storage capabilities. Additionally or alternatively, the types of AIoT devices may be distinguished by the magnitude of their peak power consumption. Additionally or alternatively, the types of AIoT devices 1 may be distinguished by whether they have uplink amplification and / or downlink amplification. Additionally or alternatively, the types of AIoT devices 1 may be distinguished by whether their uplink transmissions are backscattered transmissions on an externally supplied carrier or generated by the device's active RF components.

[0063] In one example, the AIoT device 1 may be either of the first or second types described in Non-Patent Document 1. The first type of AIoT device has a peak power consumption of about 1 μW or less, has energy storage, and does not have downlink or uplink amplification within the device. The uplink transmission of the first type of AIoT device is backscattered on an externally supplied carrier. The second type of AIoT device has a power consumption of several hundred μW or less, has energy storage, and has one or both downlink and uplink amplification. The uplink transmission of the second type of AIoT device is backscattered transmission on an externally supplied carrier or is generated by active RF components within the device.

[0064] The AIoT device 1 may have a shift register or a control module. The shift register or the control module may store multiple control functions. The control function in the AIoT device 1 may be a pre-configured or pre-programmed control signaling function stored in the shift register (or memory). Alternatively, the control function in the AIoT device 1 may be a thin protocol state control module. The thin protocol state control module may be a control module with simpler functions than the RRC state control module of existing UEs (e.g., Release 18 UEs, Narrow Band IoT (NB-IoT) devices).

[0065] Figures 1, 2, 3, and 4 correspond to Topology 1, Topology 2, Topology 3 with Downlink Assistance, and Topology 3 with Uplink Assistance, respectively, shown in Non-Patent Document 2. In Topology 1 shown in Figure 1, AIoT devices 1 communicate directly and bidirectionally with base stations 2. Communication between base stations 2 and AIoT devices 1 includes AIoT data and / or signaling. Base stations 2 may include multiple base stations. The base station that performs downlink transmissions to AIoT devices 1 may be different from the base station that receives uplink transmissions from AIoT devices 1.

[0066] In Topology 2 shown in Figure 2, an AIoT device 1 communicates bidirectionally with an intermediate node 5 located between the device and a base station 2. The intermediate node 5 may be a relay, an IAB node, a UE, or a repeater, depending on the Ambient IoT. The intermediate node 5 transfers AIoT data and / or signaling between the base station 2 and the AIoT device 1.

[0067] In the topology 3 with downlink assistance shown in Figure 3, the AIoT device 1 transmits data and / or signaling to the base station 2 and receives data and / or signaling from the assist node 6. In the topology 3 with uplink assistance shown in Figure 4, the AIoT device 1 receives data and / or signaling from the base station 2 and transmits data and / or signaling to the assist node 6. The assist node 6 may be a relay, an IAB node, a UE, or a repeater, which is compatible with Ambient IoT.

[0068] 1 to 4, the base station 2 belongs to a radio access network (RAN) 3. The RAN 3 includes one or more base stations 2. The RAN 3 may be an NG Radio Access Network (NG-RAN), and the base station 2 may be a gNB.

[0069] The base station 2 may include one or more transmitting nodes and one or more receiving nodes. Each transmitting node is configured to transmit a wireless signal to the AIoT device 1. Each receiving node is configured to receive a wireless signal transmitted by the AIoT device 1.

[0070] In the connection topologies of Figures 1 to 4, a base station 2 or RAN 3 is connected to a Core Network (CN) 4. The CN 4 includes one or more core network nodes. These core network nodes include one or more control plane nodes and one or more user plane (or data plane) nodes. In the case of a 5G system, the control plane nodes include an Access and Mobility Management Function (AMF), a Session Management Function (SMF), and other nodes (e.g., a Unified Data Management (UDM) and a Policy Control Function (PCF)), and the user plane nodes include a User Plane Function (UPF).

[0071] Additionally or alternatively, the CN4 may include new control plane nodes and / or new user plane nodes for supporting AIoT devices, which may include, for example, AIoT management functions and / or AIoT application functions.

[0072] In the connection topologies of Figures 1 to 4, the RAN 3, CN 4, intermediate node 5 (in the case of topology 2), and assist node 6 (in the case of topology 3) may forward AIoT data from the AIoT device 1 to the application server. Similarly, the RAN 3, CN 4, intermediate node 5 (in the case of topology 2), and assist node 6 (in the case of topology 3) may forward AIoT data from the application server to the AIoT device 1.

[0073] The AIoT device 1 may be referred to by other terms such as an AIoT wireless terminal, an AIoT mobile terminal, an AIoT mobile station, an AIoT wireless transmit receive unit (WTRU), an AIoT UE, or a UE in Ambient IoT. The base station 2 may be referred to by other terms such as a RAN node, an access point, or a radio station.

[0074] The user plane protocol stack of the air interface between the AIoT device 1 and the base station 2, intermediate node 5, and assist node 6 may differ from that of the air interface of 3GPP Release 18 and earlier (e.g., Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), Evolved UTRA (E-UTRA), and NR). According to the current agreement of 3GPP RAN2, the Service Data Adaptation Protocol (SDAP) sublayer, Packet Data Convergence Protocol (PDCP) sublayer, and RLC sublayer may not be required in the AIoT user plane protocol stack. Hybrid automatic repeat request (HARQ) and RLC Acknowledged Mode (AM) may not be required. Per-packet Quality of Service (QoS) and per-flow QoS may not be supported at the AS level (both uplink and downlink).

[0075] Hereinafter, the base station 2, the intermediate node 5, and the assist node 6 are collectively referred to as the "leader." As used below, the term "leader" refers to the base station 2 (in the case of Topologies 1 and 3), the intermediate node 5 (in the case of Topology 2), the assist node 6 (in the case of Topology 3), or any combination thereof. Specifically, the leader is the base station 2 in the case of Topology 1, the intermediate node 5 in the case of Topology 2, and one or a combination of the base station 2 and the assist node 6 in the case of Topology 3.

[0076] 5 shows an example of an inventory procedure. The inventory procedure may also be referred to as an inventory only procedure. In step 501, the CN4 (e.g., AIoT management function or AIoT application function) sends an inventory request message to the reader 8. As described above, the reader 8 may be a base station 2, an intermediate node 5, an assist node 6, or any combination thereof. The inventory request message may provide assistance information to the reader 8. The assistance information may include information for identifying one or more AIoT devices to be paged, such as one or more device IDs, device group IDs, or a mask (or matching filter).

[0077] If the reader 8 is an intermediate node 5, an assist node 6, or any combination thereof, the CN4 may send an inventory request message to the base station 2, and the base station 2 may further send the inventory request message to the reader 8 using the Uu interface. When transferring AIoT data and / or signaling using the Uu interface, the control plane or the user plane is used. Transfer of AIoT data and / or signaling via the control plane may use RRC signaling (including new signaling radio bearers), MAC control element (CE), and DL Control Information (DCI) format on the Uu interface. Transfer of AIoT data and / or signaling via the user plane may use dedicated data radio bearers.

[0078] In step 502, the reader 8 performs AIoT paging for inventory. Specifically, the reader 8 triggers or initiates a paging round by sending an R2D message for inventory. This R2D message is referred to herein as an initial trigger message or paging message. One paging round consists of one or more access occasions for slotted ALOHA.

[0079] The term "paging round" may be referred to by other terms such as an access round, an inventory round, a paging frame, or an access frame. The term "access occasion" may be referred to by other terms such as a time occasion, a slot, a time slot, an access slot, a response window, etc. The term "initial trigger message" or "paging message" may be referred to by other terms such as an initial paging message, a paging round initiation message, a paging round trigger message, an access round initiation message, an access round trigger message, an inventory round initiation message, or an inventory round trigger message.

[0080] The initial trigger message may include a random access (RA) setting. The RA setting may indicate the number of access occasions allocated to the paging round. To specify the number of one or more access occasions, the initial trigger message may indicate a Q value. In this case, the AIoT device may determine whether the number of access occasions in the paging round is equal to or greater than the Q power of 2 (i.e., 2 Q ) Additionally or alternatively, the RA configuration may indicate frequency resources, time resources, or both. The reader 8 may repeatedly transmit the initial trigger message so that AIoT devices that missed the initial trigger message can participate in the paging round.

[0081] In step 503, the AIoT device 1 sends a D2R message for an inventory response to the reader 8. The D2R message includes a device ID. In other words, the AIoT device 1 sends its own device ID (e.g., a device ID (AIoT device ID) of an upper layer).

[0082] In the case of an inventory of multiple AIoT devices, the AIoT device 1 transmits its device ID via contention-based RA (CBRA). The inventory of multiple AIoT devices may be an inventory targeted at a group of multiple AIoT devices, or may be an inventory targeted at all AIoT devices without including an AIoT ID. In CBRA, the AIoT device 1 randomly selects one of multiple access occasions within the paging round initiated by the initial trigger message and performs an RA procedure at the selected access occasion. The AIoT device 1 may perform a four-step-like (CB) RA procedure or a two-step-like (CB) RA procedure. The AIoT device 1 may also perform other types of random access procedures.

[0083] In the four-step-like (CB)RA procedure, the AIoT device 1 sends Msg1 containing its contention resolution ID (e.g., a random value, random ID) to the reader 8 at the selected access occasion. The contention resolution ID may be called a temporary ID. Next, the AIoT device 1 receives Msg2 for contention resolution (e.g., an echoed contention resolution ID) from the reader 8. If the contention resolution is successful, the AIoT device 1 sends Msg3 containing its device ID (upper layer device ID) to the reader 8. Msg3 may include other upper layer data. As explained in the Background section, the transmission of Msg4 in the four-step-like RA procedure may be omitted.

[0084] In a two-step-like (CB) RA procedure, the AIoT device 1 transmits Msg1, which includes its device ID (upper layer device ID) or a contention resolution ID (e.g., a random value, random ID) and its device ID, to the reader 8 in a selected access occasion. Following the terminology of NR random access, Msg1 in the two-step-like RA procedure may be referred to as message A (MsgA). The AIoT device 1 may receive Msg2 (e.g., an echoed contention resolution ID or (part of) the echoed device ID) from the reader 8. As explained in the Background section, the transmission of Msg2 in the two-step-like RA procedure may be omitted.

[0085] In step 504, the reader 8 sends the inventory response (e.g., device ID) received from the AIoT device 1 to the CN4.

[0086] As can be seen from the example of Figure 5 and as described in the Background section, communication between the AIoT device 1 and the reader 8 during the inventory procedure may be carried out in two steps: AIoT paging (step 502) and device ID transmission (step 503).

[0087] 6 shows an example of an inventory and command procedure. Steps 601 to 604 correspond to the inventory procedure. Steps 601 to 604 are similar to steps 501 to 504 in FIG.

[0088] In step 605, the CN4 (e.g., AIoT management function or AIoT application function) sends a command request to the reader 8. The command request targets any of the AIoT devices most recently inventoried in steps 601 to 604. The command may be a read command, a write command, or a disable command. A read command requests reading of data from the AIoT device 1. A write command requests storing or writing of data to the AIoT device 1. A disable command requests deactivation of the AIoT device. A disable command may request permanent deactivation of the AIoT device.

[0089] In step 606, the reader 8 sends an R2D message for a command request. The R2D message may indicate the device ID (e.g., AS Device ID) of the target AIoT device 1. The AS Device ID may be a different ID from the device ID (i.e., upper layer Device ID) sent in the inventory procedure (step 603), such as a part of the upper layer Device ID, or an ID suitable for the AIoT air interface that is shorter than the upper layer Device ID.

[0090] In step 607, the AIoT device 1 sends a D2R message to the reader 8 for a command response. In the case of a read command, the D2R message includes the data requested by the read command. In the case of a write command, the D2R message may indicate the AIoT device 1's feedback to the write command, such as an acknowledgement (ACK) or negative acknowledgement (NACK). In the case of an invalidation command, the D2R message may indicate the AIoT device 1's feedback to the invalidation command, such as an ACK or NACK.

[0091] In step 608, the reader 8 sends the command response received from the AIoT device 1 to the CN4.

[0092] 6, and as described in the Background section, communication between the AIoT device 1 and the reader 8 in the inventory and command procedure may be performed in four steps: AIoT paging (step 602), device ID transmission (step 603), command transmission (step 606), and command response (step 607). As described in the Background section, in some cases, the command response (step 607) may be omitted.

[0093] FIG. 7 shows an example of a command procedure. The command procedure may also be referred to as a command-only procedure. Steps 701 to 704 are similar to steps 605 to 608 in FIG. 6. The command-only procedure can be performed when the CN4, or the CN4 and the reader 8, know the device ID of the AIoT device. For example, the command-only procedure may be performed in a case where the AIoT device 1 recently performed an inventory procedure and the CN4 and the reader 8 still have valid context information (e.g., device ID). Alternatively, the command-only procedure may be performed in a case where the AIoT device 1 was inventoried a long time ago and the reader 8 does not have the context information (e.g., device ID) of the AIoT device 1, but the CN4 does.

[0094] Figures 8 and 9 show examples of AIoT paging and random access using slotted ALOHA. Figure 8 relates to a four-step-like (CB)RA. A leader 8 sends an initial trigger message 801. The initial trigger message 801 targets a group of AIoT devices or all AIoT devices. The initial trigger message 801 initiates a paging round 820. The paging round 820 consists of multiple access occasions, including access occasions #1 to #4.

[0095] The initial trigger message 801 includes information or a parameter (e.g., Q value) for specifying the number of access occasions in the paging round 820. Each of the multiple AIoT devices 1 randomly selects one of the multiple access occasions in the paging round 820 and attempts to transmit Msg1 including its own contention resolution ID (e.g., random value) in the selected access occasion.

[0096] Alternatively, if the initial trigger message 801 includes a single AIoT device ID or multiple IDs for multiple AIoT devices, the initial trigger message 801 may not include information or parameters for specifying the number of access occasions. In this case, each AIoT device 1 receiving the initial trigger message 801 may consider the number of access occasions to be equal to the number of AIoT devices to be paged. Each AIoT device 1 may understand that the order of its own ID within the list of one or more device IDs specified in the initial trigger message 801 corresponds to the ID or order of the access occasions assigned to it.

[0097] In the example of Figure 8, only AIoT device 1A sends Msg1 at access occasion #1. The contention resolution for this Msg1 is successful, and the leader 8 sends Msg2 indicating the contention resolution. In response to receiving Msg2, AIoT device 1A sends Msg3 (e.g., device ID, and optionally other upper layer data).

[0098] In the example of FIG. 8 , the initial trigger message 801 starts the first access occasion (i.e., access occasion #1) in the paging round 820. Alternatively, an access occasion start message for starting access occasion #1 may be transmitted separately from the initial trigger message 801. The reader 8 may transmit an independent access occasion start message for starting access occasion #1 after transmitting the initial trigger message 801. Such an implementation may be effective when the AIoT device 1A transmitting at access occasion #1 requires time for energy harvesting between receiving the initial trigger message 801 and starting to transmit Msg1.

[0099] Each subsequent access occasion is initiated by an access occasion start message. The term "access occasion start message" may be referred to by other terms such as access occasion trigger message, slot start message, slot trigger message, access slot start message, access slot trigger message, response window start message, response window trigger message, etc.

[0100] The access occasion start message 802 starts access occasion #2. In other words, the access occasion start message 802 notifies multiple AIoT devices 1 of the start of access occasion #2. Multiple AIoT devices 1 recognize the start of access occasion #2 based on receiving the access occasion start message 802. Multiple AIoT devices 1 may also recognize the end of access occasion #1 based on receiving the access occasion start message 802. In the example of FIG. 8, two AIoT devices 1B and 1C transmit Msg1 in access occasion #2. These two Msg1 transmissions collide, and contention resolution fails. Therefore, the leader 8 does not transmit Msg2. AIoT devices 1B and 1C detect a random access failure based on not receiving Msg2 for contention resolution.

[0101] The access occasion start message 803 starts access occasion #3. In other words, the access occasion start message 803 notifies multiple AIoT devices 1 of the start of access occasion #3. Multiple AIoT devices 1 recognize the start of access occasion #3 based on receiving the access occasion start message 803. Multiple AIoT devices 1 may also recognize the end of access occasion #2 based on receiving the access occasion start message 803. In the example of FIG. 8, access occasion #3 is idle. That is, since no AIoT device selected access occasion #3, Msg1 is not transmitted in access occasion #3. The leader 8 may end access occasion #3 and transmit an access occasion start message 804 to start the next access occasion #4 after the waiting time for receiving Msg1 has elapsed. For example, the leader 8 may determine that the waiting time for receiving Msg1 has elapsed by the expiration of a timer that was started upon transmission of the access occasion start message 803 for access occasion #3.

[0102] The access occasion start message 804 starts access occasion #4. In other words, the access occasion start message 804 notifies multiple AIoT devices 1 of the start of access occasion #4. Multiple AIoT devices 1 recognize the start of access occasion #4 based on receiving the access occasion start message 804. Multiple AIoT devices 1 may also recognize the end of access occasion #3 based on receiving the access occasion start message 804. In the example of FIG. 8, only AIoT device 1D sends Msg1 in access occasion #4. Contention resolution for this Msg1 is successful, and the leader 8 sends Msg2 indicating contention resolution. In response to receiving Msg2, AIoT device 1D sends Msg3 (e.g., device ID, and optionally other upper layer data).

[0103] The access occasion start message 805 starts access occasion #5. In other words, the access occasion start message 805 notifies multiple AIoT devices 1 of the start of access occasion #5. Multiple AIoT devices 1 recognize the start of access occasion #5 based on receiving the access occasion start message 805. Multiple AIoT devices 1 may also recognize the end of access occasion #4 based on receiving the access occasion start message 805.

[0104] FIG. 9 illustrates a two-step-like (CB)RA. The roles of the initial trigger message 901 and the access occasion initiation messages 902 to 905 are similar to those of the initial trigger message 801 and the access occasion initiation messages 802 to 805 shown in FIG. 8. Specifically, the initial trigger message 901 initiates a paging round 920. The paging round 920 consists of multiple access occasions, including access occasions #1 to #4. The access occasion initiation message for initiating access occasion #1 may be sent separately from the initial trigger message 901. After sending the initial trigger message 901, the leader 8 may send an independent access occasion initiation message for initiating access occasion #1. The access occasion initiation messages 902 to 905 initiate access occasions #2 to #5, respectively.

[0105] In the example of FIG. 9, only AIoT device 1A transmits Msg1 in access occasion #1. As described above, Msg1 of the 2-step-like RA may be referred to as MsgA. MsgA of the 2-step-like RA corresponds to Msg1 and Msg3 of the 4-step-like RA (FIG. 8). MsgA includes a device ID, or a contention resolution ID (e.g., a random value) and a device ID. MsgA may optionally include other upper layer data. Contention resolution for this MsgA is successful. The reader 8 may transmit Msg2 indicating contention resolution. AIoT device 1A may detect successful contention resolution and data transmission based on the reception of Msg2. However, as described above, transmission of Msg2 of the 2-step-like RA may be omitted regardless of whether contention resolution is successful or not.

[0106] In the example of Figure 9, two AIoT devices 1B and 1C transmit MsgA in access occasion #2. These two MsgA transmissions collide, and contention resolution fails. Therefore, the leader 8 does not transmit Msg2. AIoT devices 1B and 1C may detect a random access failure based on not receiving Msg2 for contention resolution.

[0107] In the example of Figure 9, access occasion #3 is idle. That is, since no AIoT device selected access occasion #3, MsgA is not transmitted during access occasion #3. The leader 8 may end access occasion #3 and transmit an access occasion start message 804 to start the next access occasion #4 when the waiting time for receiving MsgA has elapsed. For example, the leader 8 may determine that the waiting time for receiving MsgA has elapsed by detecting the expiration of a timer started upon transmission of the access occasion start message 903 for access occasion #3.

[0108] In the example of Figure 9, only AIoT device 1D transmits MsgA in access occasion #4. The contention resolution for this MsgA is successful. The leader 8 may transmit Msg2 indicating the contention resolution. The AIoT device 1D may detect the success of the contention resolution and the success of the data transmission based on the reception of Msg2. However, as described above, the transmission of Msg2 for the 2-step-like RA may be omitted regardless of whether the contention resolution is successful or not.

[0109] Figures 10 and 11 show examples of the operations of the AIoT device 1 and reader 8 in an inventory procedure using slotted ALOHA. These operations may be performed in the AIoT paging (step 502) and device ID transmission (step 503) of the inventory procedure in Figure 5. Additionally or alternatively, these operations may be performed in the AIoT paging (step 602) and device ID transmission (step 603) of the inventory and command procedure in Figure 6. Figure 10 relates to the case where the AIoT device 1 selects the first access occasion in the paging round. Meanwhile, Figure 11 relates to the case where the AIoT device 1 selects the second or subsequent access occasion in the paging round. In Figures 10 and 11, the AIoT device 1 uses a four-step-like RA procedure for device ID transmission in the selected access occasion.

[0110] 10, in step 1001, the reader 8 sends an initial trigger message. The initial trigger message indicates that a group of AIoT devices or all AIoT devices will be paged. The initial trigger message includes information or parameters (e.g., Q value) for specifying the number of access occasions in the paging round initiated by the initial trigger message.

[0111] The AIoT device 1 receives the initial trigger message. In step 1002, the AIoT device 1 randomly selects an access occasion within the paging round. Here, it is assumed that the AIoT device 1 selects the first access occasion #1.

[0112] In response to the selection of access occasion #1, the AIoT device 1 initiates a four-step-like RA procedure at access occasion #1. The four-step-like RA procedure includes sending Msg1 from the AIoT device 1 to the reader 8 (step 1003), sending Msg2 from the reader 8 to the AIoT device 1 (step 1004), and sending Msg3 from the AIoT device 1 to the reader 8 (step 1005). The four-step-like RA procedure may also include sending Msg4 from the reader 8 to the AIoT device 1 (step 1006).

[0113] As described above, an access occasion start message for starting access occasion #1 may be sent separately from the initial trigger message (1001). In this case, the AIoT device 1 that selects access occasion #1 also operates as shown in FIG.

[0114] Referring to Figure 11, steps 1101 and 1102 are similar to steps 1001 and 1002 in Figure 10. However, in step 1102, it is assumed that the AIoT device 1 selects the second or later first access occasion #n in the paging round.

[0115] In step 1103, the reader 8 sequentially transmits multiple access occasion start messages. Each of the multiple access occasion start messages starts a respective one of the second and subsequent access occasions. In response to receiving the access occasion start message for access occasion #n, the AIoT device 1 initiates a four-step-like RA procedure for access occasion #n. Steps 1104 to 1107 are similar to steps 1003 to 1006 in FIG. 10.

[0116] 12 and 13 show other examples of the operations of the AIoT device 1 and reader 8 in an inventory procedure using slotted ALOHA. These operations may be performed in the AIoT paging (step 502) and device ID transmission (step 503) of the inventory procedure in FIG. 5. Additionally or alternatively, these operations may be performed in the AIoT paging (step 602) and device ID transmission (step 603) of the inventory and command procedure in FIG. 6. FIG. 12 relates to the case where the AIoT device 1 selects the first access occasion in the paging round. On the other hand, FIG. 13 relates to the case where the AIoT device 1 selects the second or subsequent access occasion in the paging round. In FIGS. 12 and 13, the AIoT device 1 uses a two-step-like RA procedure for device ID transmission in the selected access occasion.

[0117] The procedure in Figure 12 is the same as the procedure in Figure 10, except that a two-step-like RA procedure is used instead of a four-step-like RA procedure. Steps 1201 and 1202 correspond to steps 1001 and 1002 in Figure 10. In response to selecting access occasion #1, AIoT device 1 initiates a two-step-like RA procedure at access occasion #1. The two-step-like RA procedure includes sending Msg1 (or MsgA) from the AIoT device 1 to the reader 8 (step 1203). The two-step-like RA procedure may also include sending Msg2 from the reader 8 to the AIoT device 1 (step 1204).

[0118] The procedure in Figure 13 is the same as the procedure in Figure 11, except that a two-step-like RA procedure is used instead of a four-step-like RA procedure. Steps 1301, 1302, and 1303 correspond to steps 1101, 1102, and 1103 in Figure 11. In response to selecting access occasion #n, the AIoT device 1 initiates a two-step-like RA procedure at access occasion #n. The two-step-like RA procedure includes sending Msg1 (or MsgA) from the AIoT device 1 to the reader 8 (step 1304). The two-step-like RA procedure may also include sending Msg2 from the reader 8 to the AIoT device 1 (step 1305).

[0119] 14 shows an example of the operation of the AIoT device 1 related to D2R transmission. In step 1401, the AIoT device 1 receives an R2D message. The R2D message may be an initial trigger message or an access occasion start message.

[0120] In step 1402, in response to the R2D message, the AIoT device 1 transmits a D2R message. Here, the size of the D2R message, the length of the PDU (e.g., MAC PDU) containing the D2R message, the length of the Physical Device to Reader Channel (PDRCH), the length of the PDRCH transmission duration, or the length of the access occasion in which the PDRCH is transmitted are predefined fixed values. The PDRCH is a physical channel transmitted by the AIoT device 1 to the reader 8 and carries the D2R message.

[0121] The fixed values ​​for the D2R message size, PDU length, PDRCH length, PDRCH transmission duration length, and access occasion length in which the PDRCH is transmitted may be maximum values ​​of these sizes and lengths. In other words, one or more maximum values ​​of these sizes and lengths may be predefined. One or more fixed values ​​or maximum values ​​of these sizes and lengths may be defined in a (future) 3GPP specification. One or more fixed values ​​or maximum values ​​of these sizes and lengths may be determined based on the maximum duration of timing synchronization that the AIoT device 1 acquires based on receiving an R2D message transmitted by the reader 8. The AIoT device 1 may receive a Physical Reader to Device Channel (PRDCH) carrying an R2D message from the reader 8 and acquire new timing synchronization using a preamble located at the beginning or immediately before the PRDCH. The PRDCH preamble may include an R2D timing acquisition signal.

[0122] The R2D message of step 1401 may not include a field indicating the size of the D2R message, the length of the PDU containing the D2R message, the length of the PDRCH carrying the D2R message, the length of the transmission duration of the PDRCH, or the length of the access occasion.

[0123] The operation described with reference to Figure 14 can provide details of the operation of the AIoT device 1 for D2R transmission.

[0124] Figure 15 shows an example of an R2D message format. In the example of Figure 15, an R2D message 1500 includes one or more common fields 1520 and one or more dedicated fields 1540. Each common field is a field that is included in multiple types of R2D messages. Each dedicated field is a field that is included in a specific type of R2D message but not in other types of R2D messages.

[0125] The one or more common fields 1520 include a field 1521 (e.g., a command indication field or a message type field) that indicates the message type of the R2D message 1500. For example, the field 1521 may indicate whether the R2D message 1500 is an initial trigger message, an access occasion initiation message, or an Ms2.

[0126] If the R2D message 1500 is an initial trigger message, one or more individual fields 1540 may include a field indicating a parameter (e.g., Q value) for specifying the number of multiple access occasions in one paging round initiated by the R2D message 1500. Additionally or alternatively, one or more individual fields 1540 may include a field indicating whether or not to transmit Msg4 or Msg2 (or MsgB) in a four-step-like or two-step-like RA procedure in multiple access occasions in one paging round initiated by the R2D message 1500.

[0127] If the R2D message 1500 is an access occasion initiation message, one or more individual fields 1540 may include a field indicating a parameter for identifying the access occasion initiated by the R2D message 1500. The parameter may indicate a serial number, a sequence number, or an index of the access occasion, which allows the AIoT device 1 to know the order in the paging round of the current access occasion initiated by the access occasion initiation message (1500).

[0128] Additionally or alternatively, if the R2D message 1500 is an access occasion initiation message, one or more individual fields 1540 may include a parameter for identifying an AIoT device that should respond to the access occasion initiated by the R2D message 1500. The parameter may indicate a random value or a temporary device identifier (e.g., a contention resolution ID) sent by the AIoT device in a previous access occasion within the paging round. In other words, the parameter may indicate an ID (random value or contention resolution ID) included in Msg1 (or MsgA) sent by the AIoT device in a previous access occasion within the paging round.

[0129] These types of access occasion initiation messages can be used to initiate additional or supplementary access occasions separate from the multiple access occasions that make up a paging round. If the reader 8 was unable to successfully receive a D2R transmission by an AIoT device in a previous access occasion, the reader 8 may send this type of access occasion initiation message to prompt the AIoT device to retransmit the data transmitted in the previous access occasion. Alternatively, if the reader 8 recognizes that there is pending data that could not be transmitted in the D2R transmission by an AIoT device in a previous access occasion, the reader 8 may send this type of access occasion initiation message to prompt the AIoT device to transmit the pending data. In this case, one or more individual fields 1540 may include a request to transmit the pending data.

[0130] <Second embodiment> Figure 16 shows an example of the operation of the AIoT device 1 related to D2R transmission. In step 1601, the AIoT device 1 receives an R2D message. The R2D message may be an initial trigger message or an access occasion start message. The R2D message includes fields indicating parameters for specifying the size of a D2R message to be sent by the AIoT device 1 in response to receiving the R2D message, the length of a PDU (e.g., MAC PDU) containing the D2R message, the length of a PDRCH carrying the D2R message, the length of the transmission duration of the PDRCH, or the length of the access occasion in which the PDRCH is transmitted.

[0131] In step 1602, the AIoT device 1 transmits a D2R message according to the D2R message size, PDU length, PDRCH length, PDRCH transmission duration length, or access occasion length determined based on the parameters.

[0132] The operation described with reference to Figure 16 can provide details of the operation of the AIoT device 1 for D2R transmission.

[0133] Figure 17 shows an example of an R2D message format. In the example of Figure 17, an R2D message 1700 includes one or more common fields 1720 and one or more dedicated fields 1740. Each common field is a field that is included in multiple types of R2D messages. Each dedicated field is a field that is included in a specific type of R2D message but not in other types of R2D messages.

[0134] The one or more common fields 1720 include a field 1721 (e.g., a command indication field or a message type field) that indicates the message type of the R2D message 1700. For example, the field 1721 may indicate whether the R2D message 1700 is an initial trigger message, an access occasion initiation message, or an Ms2.

[0135] One or more common fields 1720 include a field 1722 (eg, PDRCH duration field) that indicates the parameters described above.

[0136] If the R2D message 1700 is an initial trigger message, one or more individual fields 1740 may include a field indicating a parameter (e.g., Q value) for specifying the number of multiple access occasions in one paging round initiated by the R2D message 1700. Additionally or alternatively, one or more individual fields 1740 may include a field indicating whether or not to transmit Msg4 or Msg2 (or MsgB) in a four-step-like or two-step-like RA procedure in multiple access occasions in one paging round initiated by the R2D message 1700.

[0137] If the R2D message 1700 is an access occasion initiation message, one or more individual fields 1740 may include a field indicating a parameter for identifying the access occasion initiated by the R2D message 1700. The parameter may indicate a serial number, sequence number, or index of the access occasion. In one example, this allows the AIoT device 1 to know the order in the paging round of the current access occasion initiated by the access occasion initiation message (1700).

[0138] Additionally or alternatively, if the R2D message 1700 is an access occasion initiation message, one or more individual fields 1740 may include a parameter for identifying an AIoT device that should respond to the access occasion initiated by the R2D message 1700. The parameter may indicate a random value or a temporary device identifier (e.g., a contention resolution ID) sent by the AIoT device in a previous access occasion within the paging round. In other words, the parameter may indicate an ID (random value or contention resolution ID) included in Msg1 (or MsgA) sent by the AIoT device in a previous access occasion within the paging round.

[0139] These types of access occasion initiation messages can be used to initiate additional or supplementary access occasions separate from the multiple access occasions that make up a paging round. If the reader 8 was unable to successfully receive a D2R transmission by an AIoT device in a previous access occasion, the reader 8 may send this type of access occasion initiation message to prompt the AIoT device to retransmit. Alternatively, if the reader 8 recognizes that there is pending data that could not be transmitted in a D2R transmission by an AIoT device in a previous access occasion, the reader 8 may send this type of access occasion initiation message to prompt the AIoT device to transmit the pending data. In this case, one or more individual fields 1740 may include a request to transmit the pending data.

[0140] <Third embodiment> Figure 18 shows an example of D2R message transmission from an AIoT device 1 to a reader 8. In step 1801, the reader 8 sends an access occasion start message. The AIoT device 1 receives the access occasion start message. The access occasion start message includes a parameter (e.g., a serial number, a sequence number, or an index) for identifying the access occasion started by the access occasion start message.

[0141] The access occasion start message (1801) in Figure 18 enables AIoT device 1 to know the order in the paging round of the current access occasion initiated by the access occasion start message (1801).

[0142] The access occasion initiation message (1801) of Figure 18 can be used to initiate an additional or supplemental access occasion apart from the multiple access occasions that make up the paging round.

[0143] In one example, if the reader 8 was unable to successfully receive a D2R transmission by an AIoT device in a previous access occasion, the reader 8 may send this type of access occasion start message to prompt the AIoT device to retransmit the data transmitted in the previous access occasion. If the access occasion start message (1801) indicates the serial number of an access occasion in which the AIoT device 1 previously performed a D2R transmission, the AIoT device 1 may retransmit the same data transmitted in the specified previous access occasion in an additional or supplementary access occasion initiated by the access occasion start message (1801).

[0144] Alternatively, if the reader 8 recognizes that there is pending data that could not be transmitted in a D2R transmission by an AIoT device in a previous access occasion, the reader 8 may send this type of access occasion start message to prompt the AIoT device to transmit the pending data. If the access occasion start message (1801) indicates the serial number of an access occasion in which the AIoT device 1 previously performed a D2R transmission, the AIoT device 1 may transmit the pending data that could not be transmitted in the specified previous access occasion in an additional or supplementary access occasion started by the access occasion start message (1801). In this case, the access occasion start message (1801) may include a request to transmit the pending data. This transmission request may be included in a separate field in the access occasion start message.

[0145] The AIoT device 1 may inform the reader 8 that there is pending data by not including or not adding a predetermined end marker or postamble to a D2R message, a PDU (e.g., MAC PDU) containing a D2R message, or a PDRCH carrying a D2R message transmitted in a previous access occasion. The reader 8 may detect that the AIoT device 1 has pending data waiting to be transmitted based on the fact that a predetermined end marker or postamble is not included or added to a D2R message, a PDU containing a D2R message, or a PDRCH carrying a D2R message transmitted in a previous access occasion. The reader 8 may store the data received from the AIoT device 1 in a buffer and reassemble it when it receives the remaining data via an additional D2R transmission with an end marker or postamble.

[0146] As described above, the access occasion start message (1801) in Fig. 18 may start an additional or supplementary access occasion other than the multiple access occasions that make up the paging round. In this case, the AIoT device 1 may control a counter for determining the arrival of its own access occasion (i.e., an access occasion selected by itself) as follows. This counter may be called an occasion counter or a slot counter.

[0147] At the start of the paging round, the AIoT device 1 selects an access occasion and sets an initial value corresponding to the selected access occasion in the occasion counter. For example, if the AIoT device 1 receives a Q value, the AIoT device 1 sets the occasion counter from 0 to 2. Q It may randomly select an integer value between -1 and set the occasion counter to the selected value.

[0148] The AIoT device 1 receives a normal access occasion start message (e.g., access occasion start message 1103 in FIG. 11 or access occasion start message 1303 in FIG. 13) that does not include a specification of a past access occasion. In this case, the AIoT device 1 decrements the occasion counter. When the occasion counter reaches a predetermined value (e.g., zero), the AIoT device 1 attempts D2R data transmission (e.g., device ID transmission) during that access occasion.

[0149] On the other hand, if the AIoT device 1 receives an access occasion start message (1801) indicating the serial number of a past access occasion, the AIoT device 1 does not decrement the occasion counter. In other words, the AIoT device 1 understands that the current access occasion is an additional or supplementary access occasion separate from the multiple access occasions that make up the paging round.

[0150] <Fourth embodiment> Figure 19 shows an example of D2R message transmission from an AIoT device 1 to a reader 8. In step 1901, the reader 8 sends an access occasion start message. The AIoT device 1 receives the access occasion start message. The access occasion start message includes a parameter for identifying an AIoT device that should respond to the access occasion started by the access occasion start message. The parameter may indicate a random value or a temporary device identifier (e.g., a contention resolution ID) sent by the AIoT device in a previous access occasion within the paging round. In other words, the parameter may indicate an ID (random value or contention resolution ID) included in Msg1 (or MsgA) sent by the AIoT device in a previous access occasion within the paging round.

[0151] The access occasion initiation message (1901) of Figure 19 can be used to initiate an additional or supplemental access occasion apart from the multiple access occasions that make up the paging round.

[0152] In one example, if the reader 8 was unable to successfully receive a D2R transmission by an AIoT device in a previous access occasion, the reader 8 may send this type of access occasion start message to prompt the AIoT device to retransmit the data transmitted in the previous access occasion. If the access occasion start message (1901) indicates a random value or temporary device identifier (e.g., a contention resolution ID) transmitted by the AIoT device 1 in the previous access occasion, the AIoT device 1 may retransmit the same data transmitted in the specified previous access occasion in an additional or supplementary access occasion initiated by the access occasion start message (1901).

[0153] Alternatively, if the reader 8 recognizes that there is pending data that could not be transmitted in a D2R transmission by an AIoT device in a previous access occasion, the reader 8 may send this type of access occasion start message to prompt the AIoT device to transmit the pending data. If the access occasion start message (1901) indicates a random value or temporary device identifier (e.g., a contention resolution ID) transmitted by the AIoT device 1 in a previous access occasion, the AIoT device 1 may transmit the pending data that could not be transmitted in the specified previous access occasion in an additional or supplementary access occasion initiated by the access occasion start message (1901). In this case, the access occasion start message (1901) may include a request to transmit the pending data. This transmission request may be included in a separate field within the access occasion start message.

[0154] The AIoT device 1 may inform the reader 8 that there is pending data by not including or not adding a predetermined end marker or postamble to a D2R message, a PDU (e.g., MAC PDU) containing a D2R message, or a PDRCH carrying a D2R message transmitted in a previous access occasion. The reader 8 may detect that the AIoT device 1 has pending data waiting to be transmitted based on the fact that a predetermined end marker or postamble is not included or added to a D2R message, a PDU containing a D2R message, or a PDRCH carrying a D2R message transmitted in a previous access occasion. The reader 8 may store the data received from the AIoT device 1 in a buffer and reassemble it when it receives the remaining data via an additional D2R transmission with an end marker or postamble.

[0155] As described above, the access occasion start message (1901) in Figure 19 may start an additional or supplementary access occasion other than the multiple access occasions that make up the paging round. In this case, the AIoT device 1 may control a counter for determining the arrival of its own access occasion (i.e., an access occasion selected by itself). This counter may be called an occasion counter or a slot counter. Details of the occasion counter control may be similar to those described in the third embodiment.

[0156] Fifth Embodiment FIG. 20 shows an example of the operation of the AIoT device 1 related to D2R transmission. In step 2001, the AIoT device 1 receives an access occasion start message. The access occasion start message starts one of multiple access occasions in a paging round initiated by an initial trigger (or paging) message. The access occasion start message includes information indicating the order of the current access occasion initiated by the access occasion start message within the paging round (i.e., multiple access occasions). This information enables the AIoT device 1 to know the order of the current access occasion from the first access occasion in the paging round. This information may be a parameter for specifying the serial number, sequence number, or index of the current access occasion. This information may also be the serial number, sequence number, or index of the current access occasion. In step 2002, the AIoT device 1 recognizes the order of the current access occasion within the multiple access occasions based on the received information.

[0157] The operation shown in FIG. 20 enables the AIoT device 1 to determine the order of the current access occasion in the paging round initiated by the access occasion start message based on information included in the received access occasion start message. According to the operation shown in FIG. 20, the AIoT device 1 can determine the order of the current access occasion in the paging round without counting the number of access occasion start messages transmitted within the access occasion. In other words, the AIoT device 1 is not necessarily required to receive and count all access occasion start messages transmitted within an access occasion to determine the arrival of its selected access occasion. For example, this can enable the AIoT device 1 to enter a sleep state after the start of an access round but before its own access occasion arrives. Such an implementation may be effective when the AIoT device 1 requires time for energy harvesting after receiving the initial trigger message and before starting to transmit Msg1.

[0158] The AIoT device 1 may control a counter for determining the arrival of its own access occasion (i.e., an access occasion selected by itself) as shown in FIG. 21. This counter may be called an occasion counter or a slot counter. In step 2101, the AIoT device 1 selects an access occasion at the start of a paging round and sets an initial value corresponding to the selected access occasion in the occasion counter. For example, if the AIoT device 1 receives a Q value, the AIoT device 1 counts the Q value from 0 to 2. Q It may randomly select an integer value between -1 and set the occasion counter to the selected value.

[0159] After step 2101, the AIoT device 1 may enter a sleep state. In the sleep state, the AIoT device 1 may not receive an R2D message including an access occasion start message.

[0160] Step 2102 is similar to step 2001 in Figure 20. That is, the AIoT device 1 receives an access occasion start message containing information indicating the current access occasion order. Before step 2102, the AIoT device 1 may return from a sleep state to an on state.

[0161] In step 2103, the AIoT device 1 updates the occasion counter by decrementing the number corresponding to the current access occasion from the initial value of the counter, thereby allowing the AIoT device 1 to update the occasion counter to the latest state without having to receive and count all access occasion start messages sent within the access occasion.

[0162] 22 shows an example of the operation of the AIoT device 1 and the reader 8. In step 2201, the reader 8 sends an initial trigger message. The initial trigger message indicates that a group of AIoT devices or all AIoT devices will be paged. The initial trigger message includes information or a parameter (e.g., Q value) for specifying the number of access occasions in the paging round initiated by the initial trigger message.

[0163] The AIoT device 1 receives the initial trigger message. In step 2202, the AIoT device 1 randomly selects an access occasion within the paging round. Here, it is assumed that the AIoT device 1 selects the third or later first access occasion #n within the paging round. The AIoT device 1 sets the initial value of the occasion counter to a number (e.g., n or n-1) corresponding to the selected access occasion.

[0164] In step 2203, the AIoT device 1 enters a sleep state. In the sleep state, the AIoT device 1 may not receive an R2D message including an access occasion start message 2204.

[0165] In step 2205, after returning from the sleep state to the on state, the AIoT device 1 receives an access occasion start message indicating access occasion #m. Here, it is assumed that access occasion #m precedes access occasion #n, that is, integer m is smaller than integer n. In step 2206, the AIoT device 1 updates the occasion counter by decrementing the number corresponding to the current access occasion (e.g., m or m-1) from the initial value (e.g., n or n-1).

[0166] In step 2207, the AIoT device 1 receives an access occasion start message indicating access occasion #n. In response, the AIoT device 1 initiates random access at access occasion #n (step 2208). This random access may be the four-step-like RA procedure or the two-step-like RA procedure described above. This random access may also be another type of RA procedure.

[0167] <Sixth embodiment> Figure 23 shows an example of the operation of the AIoT device 1 related to D2R transmission. In step 2301, the AIoT device 1 determines the start or arrival of a selected access occasion. In the selected access occasion, the AIoT device 1 performs D2R data transmission. If the D2R transmission is completed within the access occasion, the AIoT device 1 includes (or adds) an end marker or postamble to the D2R message, the PDU (e.g., MAC PDU) containing the D2R message, or the PDRCH carrying the D2R message (step 2302). On the other hand, if the D2R transmission is not completed within the access occasion and there is pending data, the AIoT device 1 does not include (or add) an end marker or postamble to the D2R message, PDU, or PDRCH (step 2303).

[0168] For example, the operation shown in Figure 23 allows the reader 8 to know whether a D2R transmission has been completed within an access occasion (i.e., whether there is pending data waiting to be transmitted). If the reader 8 recognizes that there is pending data that could not be transmitted in a D2R transmission by an AIoT device in a previous access occasion, the reader 8 may prompt the AIoT device to transmit the pending data. To trigger the transmission of the pending data, for example, the reader 8 may transmit an access occasion start message of the type described in the second embodiment. Alternatively, the reader 8 may transmit an access occasion start message of the type described in the third embodiment.

[0169] FIG. 24 shows an example of the operation of the reader 8. In step 2401, the reader 8 determines that there is pending data that could not be transmitted in a D2R transmission by the AIoT device 1 in a previous access occasion. As described above, the reader 8 may determine that the AIoT device 1 has pending data if the D2R message, the PDU (e.g., MAC PDU) containing the D2R message, or the PDRCH carrying the D2R message received from the AIoT device 1 in the access occasion does not include or is not accompanied by a predetermined end marker or postamble. In step 2402, the reader 8 transmits an access occasion start message including information identifying the serial number of the previous access occasion. This type of access occasion start message initiates an additional or supplementary access occasion separate from the multiple access occasions that make up the paging round. This type of access occasion start message prompts the AIoT device 1 that transmitted in the previous access occasion identified by the serial number specified in the message to transmit the pending data.

[0170] Additionally or alternatively, the operation shown in Figure 23 can enable the reader 8 to know that the D2R transmission within an access occasion has completed early, before the arrival of the access occasion duration. In this case, if the actual D2R transmission duration is shorter than a predetermined default value (e.g., a maximum value, a fixed value), the AIoT device 1 may indicate the completion or early completion of the D2R transmission to the reader 8 by including or adding an end marker or postamble to the D2R message, the PDU containing the D2R message, or the PDRCH carrying the D2R message. Upon detecting the completion or early completion of the D2R transmission, the reader 8 can end the access occasion and start the next access occasion before the period corresponding to the default value has elapsed.

[0171] Seventh Embodiment This embodiment relates to how to support command (only) procedures.

[0172] In some other implementations, the command type that can use the command procedure is limited to only the disable command. The command procedure cannot be used for read commands and write commands. In this case, the CN4 and reader 8 may use the command procedure to send a disable command to the AIoT device 1. When sending a read command or a write command, the CN4 and reader 8 always use the inventory and command procedure.

[0173] In other implementations, the command procedure can only be used when the command targets only one AIoT device. The command procedure cannot be used for commands targeting a group of AIoT devices or all AIoT devices. In this case, the CN4 and reader 8 may use the command procedure to send a command targeting one AIoT device. When sending a command targeting a group of AIoT devices or all AIoT devices, the CN4 and reader 8 always use the inventory and command procedure.

[0174] <Eighth embodiment> This embodiment relates to whether step D, i.e., D2R transmission (e.g., feedback) from the corresponding AIoT device 1 to the reader 8, is used in the inventory and command procedure.

[0175] In some implementations, whether to use step D is predefined for each type of command sent from the reader 8 to the AIoT device 1 in step C of the inventory and command procedure. This definition may be specified in a (future) 3GPP specification. Step C of the inventory and command procedure is R2D data transmission (e.g., R2D command) from the reader 8 to the AIoT device 1. Command types include, for example, read commands, write commands, and invalidation commands. For example, if a read command is sent in step C, the AIoT device 1 performs D2R transmission in step D and transmits AIoT device data to the reader 8. If a write command is sent in step C, the AIoT device 1 may not need to send an ACK / NACK response to the write command to the reader 8 in step D. If an invalidation command is sent in step C, the AIoT device 1 may not need to send an ACK / NACK response to the invalidation command to the reader 8 in step D.

[0176] In another implementation, the reader 8 sets or indicates to the AIoT device 1 whether step D is required when sending a command from the reader 8 to the AIoT device 1 in step C. The AIoT device 1 decides whether to perform D2R transmission in step D according to the setting or instruction received in step C.

[0177] Ninth Embodiment This embodiment relates to specifying resources used for D2R transmission (PDRCH transmission). The resources include one or both of frequency resources and time resources. The resources may be resources for random access (e.g., Msg1 transmission).

[0178] In some implementations, one or both of the initial trigger (or paging) message and the access occasion start message explicitly indicate information that allows the AIoT device 1 to determine the resources to use for the response (i.e., PDRCH transmission). For example, one or both of the initial trigger message and the access occasion start message indicate the identification of a pre-configured resource set.

[0179] The initial trigger message may not include an explicit indication of whether the resources for PDRCH transmission are dedicated resources or shared resources. For example, the initial trigger message may implicitly indicate that the resources for PDRCH transmission are shared by including information for specifying the number of access occasions. On the other hand, the initial trigger message may implicitly indicate that the resources for PDRCH transmission are dedicated resources by not including information for specifying the number of access occasions (e.g., by including the ID of a single AIoT device or multiple IDs of multiple AIoT devices).

[0180] Similarly, the access occasion start message may not include an explicit indication of whether the resources for PDRCH transmission are dedicated resources or shared resources. For example, the access occasion start message may implicitly indicate that the resources for PDRCH transmission are shared by not including a dedicated field. Conversely, the access occasion start message may implicitly indicate that the resources for PDRCH transmission are dedicated resources by including a dedicated field.

[0181] In these cases, if the initial trigger message or the access occasion start message indicates only one resource, the AIoT device 1 may understand that the resource is a dedicated resource. On the other hand, if the initial trigger message or the access occasion start message indicates multiple resources, the AIoT device 1 may understand that these resources are shared resources.

[0182] In another implementation, a fixed correspondence between (random access) resources for PDRCH transmission and the initial trigger message is predefined. Additionally or alternatively, a fixed correspondence between (random access) resources for PDRCH transmission and the access occasion start message is predefined. These definitions may be specified in (future) 3GPP specifications. Alternatively, these correspondences may be configured in advance in the AIoT device 1. For example, the correspondence between the frequency of the carrier on which the initial trigger message or the access occasion start message is transmitted and the frequency resource for PDRCH transmission may be fixed. Alternatively, this correspondence may be predefined in the AIoT device 1. In this case, one or both of the initial trigger message and the access occasion start message may not include an explicit indication of the resource for PDRCH transmission.

[0183] Next, configuration examples of the AIoT device 1, base station 2, intermediate node 5, and assist node 6 related to the above-described embodiments will be described below. FIG. 25 shows a configuration example of the AIoT device 1. Referring to FIG. 25, the AIoT device 1 includes an energy harvester 2501, a power management 2502, an energy storage 2503, a controller 2504, a memory 2505, an RF circuit 2506, and an antenna 2507. The energy harvester 2501 converts radio waves, light, motion, heat, or other energy into electric power. The power management 2502 stores the power generated by the energy harvester 2501 in the energy storage 2503 (e.g., a capacitor) and controls the power supply to the controller 2504, the memory 2505, and the RF circuit 2506.

[0184] Controller 2504 receives signaling, data, and signals via RF circuitry 2506. Controller 2504 accesses memory 2505 and generates signaling, data, and signals that are transmitted via RF circuitry 2506. Controller 2504 may be pre-set or pre-programmed control signaling functions stored in memory 2505 (e.g., shift registers). Alternatively, controller 2504 may be a thin protocol state control module.

[0185] The RF circuit 2506 is coupled to an antenna 2507. If the AIoT device 1 is a device that performs backscatter communication, the RF circuit 2506 may include RF circuits such as a demodulator and a modulator (frequency multiplier). If the AIoT device 1 generates an uplink signal using its own active RF components, the RF circuit 2506 may be an active RF transceiver.

[0186] Figure 26 shows an example configuration of a base station 2. Referring to Figure 26, the base station 2 includes an RF transceiver 2601, a network interface 2603, a processor 2604, and a memory 2605. The RF transceiver 2601 performs analog RF signal processing to communicate with the AIoT device 1, the intermediate node 5, the assist node 6, and other UEs. The RF transceiver 2601 may include multiple transceivers. In particular, the RF transceiver 2601 may include one or more transceivers for a Uu interface with the intermediate node 5, the assist node 6, and other UEs, and a transceiver for communicating with multiple AIoT devices including the AIoT device 1. In addition to the RF transceiver 2601, the base station 2 may also include an RF transmitter for supplying RF power to the AIoT devices.

[0187] The RF transceiver 2601 is coupled to the antenna array 2602 and the processor 2604. For example, the RF transceiver 2601 receives modulation symbol data from the processor 2604, generates a transmit RF signal, and provides the transmit RF signal to the antenna array 2602. The RF transceiver 2601 also generates a baseband receive signal based on the receive RF signal received by the antenna array 2602 and provides the baseband receive signal to the processor 2604. The RF transceiver 2601 may include an analog beamformer circuit for beamforming. The analog beamformer circuit includes, for example, multiple phase shifters and multiple power amplifiers.

[0188] The network interface 2603 is used to communicate with network nodes (e.g., other base stations, control plane nodes and user plane nodes in the CN4), and may include, for example, a network interface card (NIC) conforming to the IEEE 802.3 series.

[0189] The processor 2604 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The processor 2604 may include multiple processors. For example, the processor 2604 may include a modem processor (e.g., a Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., a Central Processing Unit (CPU) or a Micro Processing Unit (MPU)) that performs control plane processing.

[0190] For example, digital baseband signal processing by processor 2604 may include signal processing for the Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and Physical (PHY) layer. Control plane processing by processor 2604 may also include processing of Non-Access Stratum (NAS) messages, RRC messages, MAC Control Elements (CEs), and Downlink Control Information (DCI).

[0191] The processor 2604 may include a digital beamformer module for beamforming, which may include a Multiple Input Multiple Output (MIMO) encoder and precoder.

[0192] The memory 2605 is configured by a combination of volatile memory and non-volatile memory. The volatile memory is, for example, Static Random Access Memory (SRAM), Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is, for example, Mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. The memory 2605 may include storage located remotely from the processor 2604. In this case, the processor 2604 may access the memory 2605 via the network interface 2603 or an I / O interface (not shown).

[0193] The memory 2605 may store one or more software modules (computer programs) 2606 including instructions and data for performing the processes of the base station 2 described in the above embodiments. In some implementations, the processor 2604 may be configured to read and execute the software modules 2606 from the memory 2605 to perform the processes of the base station 2 described in the above embodiments.

[0194] It should be noted that the control plane processing and operations performed by base station 2 described in the above embodiment can be realized by elements other than RF transceiver 2601 and antenna array 2602, namely processor 2604 and memory 2605 storing software module 2606.

[0195] Figure 27 shows an example configuration of the intermediate node 5. In the example of Figure 27, the intermediate node 5 is a UE. The configuration of the assist node 6 may also be similar to the configuration shown in Figure 27. The RF transceiver 2701 performs analog RF signal processing to communicate with the base station 2. In addition, the RF transceiver 2701 performs analog RF signal processing to communicate with multiple AIoT devices including the AIoT device 1. The RF transceiver 2701 may include multiple transceivers. In particular, the RF transceiver 2701 may include one or more transceivers for a Uu interface with the base station 2 and a transceiver for communicating with multiple AIoT devices including the AIoT device 1.

[0196] The analog RF signal processing performed by the RF transceiver 2701 includes frequency up-conversion, frequency down-conversion, and amplification. The RF transceiver 2701 is coupled to the antenna array 2702 and the baseband processor 2703. For example, the RF transceiver 2701 receives modulation symbol data (or orthogonal frequency-division multiplexing (OFDM) symbol data) from the baseband processor 2703, generates a transmit RF signal, and provides the transmit RF signal to the antenna array 2702. The RF transceiver 2701 also generates a baseband receive signal based on the receive RF signal received by the antenna array 2702 and provides it to the baseband processor 2703. The RF transceiver 2701 may include an analog beamformer circuit for beamforming. The analog beamformer circuit may include, for example, multiple phase shifters and multiple power amplifiers.

[0197] The baseband processor 2703 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communications. Digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) transmission format (transmission frame) generation / decomposition, (d) transmission path coding / decoding, (e) modulation (symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) using Inverse Fast Fourier Transform (IFFT). Meanwhile, control plane processing includes communication management for Layer 1 (e.g., transmit power control), Layer 2 (e.g., radio resource management and hybrid automatic repeat request (HARQ) processing), and Layer 3 (e.g., signaling related to attachment, mobility, and call management).

[0198] For example, the digital baseband signal processing by the baseband processor 2703 may include signal processing of the SDAP layer, PDCP layer, RLC layer, MAC layer, and PHY layer. Also, the control plane processing by the baseband processor 2703 may include processing of the Non-Access Stratum (NAS) protocol, the RRC protocol, MAC CEs, and DCIs.

[0199] The baseband processor 2703 may perform MIMO encoding and precoding for beamforming.

[0200] The baseband processor 2703 may include a modem processor (e.g., DSP) that performs digital baseband signal processing and a protocol stack processor (e.g., CPU or MPU) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 2704, which will be described later.

[0201] The application processor 2704 is also referred to as a CPU, MPU, microprocessor, or processor core. The application processor 2704 may include multiple processors (multiple processor cores). The application processor 2704 executes a system software program (operating system (OS)) and various application programs read from the memory 2706 or a memory not shown, thereby realizing various functions of the intermediate node 5.

[0202] In some implementations, the baseband processor 2703 and the application processor 2704 may be integrated on a single chip, as shown by the dashed line (2705) in Figure 27. In other words, the baseband processor 2703 and the application processor 2704 may be implemented as a single System on Chip (SoC) device 2705. An SoC device is sometimes called a system Large Scale Integration (LSI) or chipset.

[0203] The memory 2706 is volatile memory, nonvolatile memory, or a combination thereof. The memory 2706 may include multiple physically independent memory devices. The volatile memory is, for example, SRAM, DRAM, or a combination thereof. The nonvolatile memory is, for example, MROM, EEPROM, flash memory, or a hard disk drive, or any combination thereof. For example, the memory 2706 may include an external memory device accessible from the baseband processor 2703, the application processor 2704, and the SoC 2705. The memory 2706 may also include an internal memory device integrated within the baseband processor 2703, the application processor 2704, or the SoC 2705. Furthermore, the memory 2706 may include memory within a Universal Integrated Circuit Card (UICC).

[0204] The memory 2706 may store one or more software modules (computer programs) 2707 including instructions and data for performing the processing by the intermediate node 5 described in the above-described embodiments. In some implementations, the baseband processor 2703 or the application processor 2704 may be configured to read and execute the software modules 2707 from the memory 2706, thereby performing the processing by the intermediate node 5 described in the above-described embodiments using the drawings.

[0205] It should be noted that the control plane processing and operations performed by the intermediate node 5 described in the above embodiment can be realized by elements other than the RF transceiver 2701 and the antenna array 2702, namely, at least one of the baseband processor 2703 and the application processor 2704, and the memory 2706 storing the software module 2707.

[0206] As described with reference to FIGS. 25 to 27 , each of the processors included in the AIoT device 1, base station 2, intermediate node 5, and assist node 6 according to the above-described embodiments can execute one or more programs including instructions for causing a computer to perform the algorithms described with reference to the drawings. The programs include instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The programs may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disk (DVD), Blu-ray (registered trademark) disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage device. The programs may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0207] The above-described embodiments are merely examples of application of the technical ideas obtained by the inventors of the present invention. In other words, the technical ideas are not limited to the above-described embodiments, and various modifications are possible.

[0208] For example, some or all of the above embodiments may also be described as, but are not limited to, the following appendices. Some or all of the elements (e.g., configurations and functions) described in appendices directed to apparatuses (e.g., AIoT devices, readers) may naturally also be described as appendices directed to methods and programs. For example, some or all of the elements described in appendices 2-7, which are dependent on appendices 1, may also be described as appendices dependent on appendices 8 and 9, due to the same dependency relationship as appendices 2-7. Similarly, some or all of the elements described in appendices 11-16, which are dependent on appendices 10, may also be described as appendices dependent on appendices 17 and 18, due to the same dependency relationship as appendices 11-16. Some or all of the elements described in any appendice may be applicable to various hardware, software, recording means for recording software, systems, and methods.

[0209] (Supplementary Note 1) An Ambient Internet of Things (AIoT) device comprising: means for receiving a first reader to device (R2D) message; and means for transmitting a device to reader (D2R) message in response to the first R2D message, wherein a size of the D2R message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion on which the physical channel is transmitted are predefined fixed values. (Supplementary Note 2) The AIoT device according to Supplementary Note 1, wherein the first R2D message does not include a field indicating the size of the D2R message, the length of the PDU, the length of the physical channel, the length of the transmission duration of the physical channel, or the length of the access occasion. (Supplementary Note 3) The AIoT device according to Supplementary Note 1 or 2, wherein the first R2D message includes one or more common fields and one or more individual fields, wherein each common field is a field that is included in multiple types of R2D messages, and each individual field is a field that is included in a specific type of R2D message but not in other types of R2D messages, and the one or more common fields include a field that indicates a message type of the first R2D message. (Supplementary Note 4) The AIoT device according to Supplementary Note 3, wherein the first R2D message is a paging message or an initial trigger message, and the one or more individual fields include a field that indicates a parameter for specifying the number of multiple access occasions in one paging round initiated by the first R2D message.(Supplementary Note 5) The AIoT device of Supplementary Note 3, wherein the first R2D message is an access occasion initiation message for initiating one of a plurality of access occasions in a paging round initiated by an initial trigger or a paging message, and the one or more individual fields include a field indicating a parameter for identifying the access occasion initiated by the first R2D message. (Supplementary Note 6) The AIoT device of Supplementary Note 3, wherein the first R2D message is an access occasion initiation message for initiating one of a plurality of access occasions in a paging round initiated by an initial trigger or a paging message, and the one or more individual fields include a parameter for identifying an AIoT device that should respond in the access occasion initiated by the first R2D message. (Supplementary Note 7) The AIoT device of Supplementary Note 6, wherein the parameter indicates a random value or a temporary device identifier sent by the AIoT device in a past access occasion in the paging round. (Supplementary Note 8) A method performed by an Ambient Internet of Things (AIoT) device, comprising: receiving a first reader to device (R2D) message; and transmitting a device to reader (D2R) message in response to the first R2D message; wherein a size of the D2R message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion on which the physical channel is transmitted is a predefined fixed value.(Supplementary Note 9) A program causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, comprising: receiving a first reader to device (R2D) message; and transmitting a device to reader (D2R) message in response to the first R2D message; wherein the size of the D2R message, the length of a Protocol Data Unit (PDU) containing the D2R message, the length of a physical channel carrying the D2R message, the length of a transmission duration of the physical channel, or the length of an access occasion over which the physical channel is transmitted are predefined fixed values. (Supplementary Note 10) A reader comprising: means for transmitting a first reader to device (R2D) message; and means for receiving a device to reader (D2R) message transmitted by an Ambient Internet of Things (AIoT) device in response to the first R2D message, wherein a size of the D2R message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted is a predefined fixed value. (Supplementary Note 11) The reader according to Supplementary Note 10, wherein the first R2D message does not include a field indicating the size of the D2R message, the length of the PDU, the length of the physical channel, the length of the transmission duration of the physical channel, or the length of the access occasion. (Supplementary Note 12) The reader described in Supplementary Note 10 or 11, wherein the first R2D message includes one or more common fields and one or more individual fields, each common field being a field that is included in multiple types of R2D messages, and each individual field being a field that is included in a particular type of R2D message but not in other types of R2D messages, and the one or more common fields include a field that indicates the message type of the first R2D message.(Supplementary Note 13) The reader according to Supplementary Note 12, wherein the first R2D message is a paging message or an initial trigger message, and the one or more individual fields include a field indicating a parameter for specifying a number of multiple access occasions in one paging round initiated by the first R2D message. (Supplementary Note 14) The reader according to Supplementary Note 12, wherein the first R2D message is an access occasion initiation message for initiating one of multiple access occasions in a paging round initiated by an initial trigger or a paging message, and the one or more individual fields include a field indicating a parameter for identifying the access occasion initiated by the first R2D message. (Supplementary Note 15) The reader of Supplementary Note 12, wherein the first R2D message is an access occasion initiation message for initiating one of a plurality of access occasions in a paging round initiated by an initial trigger or a paging message, and the one or more individual fields include a parameter for identifying an AIoT device that should respond in the access occasion initiated by the first R2D message. (Supplementary Note 16) The reader of Supplementary Note 15, wherein the parameter indicates a random value or a temporary device identifier sent by the AIoT device in a previous access occasion in the paging round. (Supplementary Note 17) A method performed by a reader, comprising: transmitting a first reader to device (R2D) message; and receiving a device to reader (D2R) message transmitted by an Ambient Internet of Things (AIoT) device in response to the first R2D message, wherein a size of the D2R message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion on which the physical channel is transmitted is a predefined fixed value.(Supplementary Note 18) A program that causes a computer to perform a method for a reader, comprising: sending a first reader to device (R2D) message; and receiving a device to reader (D2R) message sent by an Ambient Internet of Things (AIoT) device in response to the first R2D message, wherein the size of the D2R message, the length of a Protocol Data Unit (PDU) containing the D2R message, the length of a physical channel carrying the D2R message, the length of a transmission duration of the physical channel, or the length of an access occasion over which the physical channel is transmitted are predefined fixed values. (Supplementary Note 19) An AIoT device comprising: means for receiving a first reader to device (R2D) message, wherein the first R2D message includes a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be sent in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted; and means for transmitting the D2R message in accordance with the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter. (Supplementary Note 20) The AIoT device described in Supplementary Note 19, wherein the first R2D message includes one or more common fields and one or more individual fields, each common field being a field that is included in multiple types of R2D messages, each individual field being a field that is included in a particular type of R2D message but not in other types of R2D messages, and the first field is one of the one or more common fields.(Supplementary Note 21) The AIoT device according to Supplementary Note 19 or 20, wherein the first R2D message is a paging message or an initial trigger message for initiating a paging round including multiple access occasions. (Supplementary Note 22) The AIoT device according to Supplementary Note 19 or 20, wherein the first R2D message is an access occasion initiation message for initiating one of multiple access occasions in a paging round initiated by the initial trigger or paging message. (Supplementary Note 23) A method performed by an AIoT device, comprising: receiving a first reader to device (R2D) message, wherein the first R2D message includes a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be transmitted in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted; and transmitting the D2R message in accordance with the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter.(Supplementary Note 24) A program for causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, comprising: receiving a first reader to device (R2D) message, wherein the first R2D message includes a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be transmitted in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted; and transmitting the D2R message in accordance with the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter. (Supplementary Note 25) A reader comprising: means for transmitting a first reader to device (R2D) message, the first R2D message including a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be transmitted by an Ambient Internet of Things (AIoT) device in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted. (Supplementary Note 26) The reader according to Supplementary Note 25, further comprising means for receiving the D2R message transmitted by the AIoT device according to the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter.(Supplementary Note 27) The reader according to Supplementary Note 25 or 26, wherein the first R2D message includes one or more common fields and one or more individual fields, wherein each common field is a field that is included in multiple types of R2D messages, and each individual field is a field that is included in a specific type of R2D message but not in other types of R2D messages, and the first field is one of the one or more common fields. (Supplementary Note 28) The reader according to any one of Supplements 25 to 27, wherein the first R2D message is a paging message or an initial trigger message for initiating a paging round including multiple access occasions. (Supplementary Note 29) The reader according to any one of Supplements 25 to 27, wherein the first R2D message is an access occasion initiation message for initiating one of multiple access occasions in a paging round initiated by the initial trigger or paging message. (Supplementary Note 30) A method performed by a reader, comprising: transmitting a first reader to device (R2D) message, the first R2D message including a first field indicating parameters for specifying a size of a device to reader (D2R) message to be sent by an Ambient Internet of Things (AIoT) device in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted.(Supplementary Note 31) A program causing a computer to perform a method for a reader, comprising transmitting a first reader to device (R2D) message, the first R2D message including a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be sent by an Ambient Internet of Things (AIoT) device in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted. (Supplementary Note 32) An AIoT device comprising: means for receiving a first type access occasion initiation message, wherein the first type access occasion initiation message is transmitted to initiate one of a plurality of access occasions in a paging round initiated by an initial trigger message or a paging message, and wherein the first type access occasion initiation message includes a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message. (Supplementary Note 33) The AIoT device according to Supplementary Note 32, wherein the first type access occasion initiation message includes the second parameter. (Supplementary Note 34) The AIoT device according to Supplementary Note 33, wherein the second parameter indicates a random value or a temporary device identifier transmitted by the AIoT device in a previous access occasion in the paging round. (Supplementary Note 35) The AIoT device of Supplementary Note 32, wherein the first type access occasion start message includes the first parameter.(Supplementary Note 36) The AIoT device according to any one of Supplements 32 to 35, further comprising means for operating a counter for determining the arrival of its own access occasion, wherein the receiving means is configured to receive a second type access occasion start message that does not include the first parameter or the second parameter, and the operating means is configured to: decrement the counter when receiving the second type access occasion start message, and not decrement the counter when receiving the first type access occasion start message. (Supplementary Note 37) The AIoT device according to any one of Supplements 32 to 36, wherein the access occasion started by the first type access occasion start message is an additional or supplementary access occasion separate from the multiple access occasions specified by the initial trigger message or the paging message. (Supplementary Note 38) The AIoT device according to any one of Supplements 32 to 37, wherein the first type access occasion start message is transmitted by the reader when the reader was unable to successfully receive a device to reader (D2R) transmission by the AIoT device in a past access occasion. (Supplementary Note 39) The AIoT device according to Supplementary Note 38, further comprising: means for retransmitting data transmitted in the past access occasion in an access occasion initiated by the first type access occasion start message. (Supplementary Note 40) The AIoT device according to any one of Supplements 32 to 37, wherein the first type access occasion start message is transmitted by the reader when the reader recognizes that there is pending data that could not be transmitted in a device to reader (D2R) transmission by the AIoT device in a past access occasion. (Supplementary Note 41) The AIoT device according to Supplementary Note 40, further comprising: means for transmitting the pending data in an access occasion initiated by the first type access occasion start message.(Supplementary Note 42) The AIoT device according to Supplementary Note 40 or 41, further comprising means for notifying the reader of the presence of the pending data by not including or not adding a predetermined end marker or postamble to a D2R message transmitted in the previous access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message. (Supplementary Note 43) A method performed by an AIoT device, comprising receiving a first type access occasion initiation message, the first type access occasion initiation message being transmitted to initiate one of a plurality of access occasions in a paging round initiated by an initial trigger message or a paging message, the first type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first type access occasion initiation message, or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message. (Supplementary Note 44) A program causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, the method comprising receiving a first type access occasion initiation message, the first type access occasion initiation message being sent to initiate one of a plurality of access occasions in a paging round initiated by an initial trigger message or a paging message, the first type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first type access occasion initiation message, or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message.(Supplementary Note 45) A reader comprising: means for transmitting a first type access occasion initiation message, wherein the first type access occasion initiation message is transmitted to initiate one of a plurality of access occasions in a paging round initiated by an initial trigger message or a paging message, and wherein the first type access occasion initiation message includes a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message. (Supplementary Note 46) The reader according to Supplementary Note 45, wherein the first type access occasion initiation message includes the second parameter. (Supplementary Note 47) The reader according to Supplementary Note 46, wherein the second parameter indicates a random value or a temporary device identifier transmitted by the AIoT device in a previous access occasion in the paging round. (Supplementary Note 48) The reader according to Supplementary Note 45, wherein the first type access occasion start message includes the first parameter. (Supplementary Note 49) The reader according to any one of Supplements 45 to 48, wherein the transmitting means is configured to transmit a second type access occasion start message that does not include the first parameter or the second parameter, the second type access occasion start message causing the AIoT device to decrement a counter for determining the arrival of its own access occasion when receiving the second type access occasion start message, and the first type access occasion start message causing the AIoT device not to decrement the counter when receiving the first type access occasion start message.(Supplementary Note 50) The reader according to any one of Supplements 45 to 49, wherein the access occasion initiated by the first type access occasion initiation message is an additional or auxiliary access occasion separate from the multiple access occasions specified by the initial trigger message or the paging message. (Supplementary Note 51) The reader according to any one of Supplements 45 to 50, wherein the transmitting means is configured to transmit the first type access occasion initiation message when the reader was unable to successfully receive a device to reader (D2R) transmission by the AIoT device in a previous access occasion. (Supplementary Note 52) The reader according to Supplementary Note 51, wherein the first type access occasion initiation message causes the AIoT device to retransmit data transmitted in the previous access occasion in the access occasion initiated by the first type access occasion initiation message. (Supplementary Note 53) The reader according to any one of Supplements 45 to 50, wherein the transmitting means is configured to transmit the first type access occasion start message when the reader recognizes that there is pending data that could not be transmitted in a device to reader (D2R) transmission by the AIoT device in a past access occasion. (Supplementary Note 54) The reader according to Supplementary Note 53, wherein the first type access occasion start message causes the AIoT device to transmit the pending data in the access occasion initiated by the first type access occasion start message. (Supplementary Note 55) The reader according to Supplementary Note 53 or 54, further comprising means for detecting the presence of the pending data based on the absence of a predetermined end marker or postamble in a D2R message transmitted in the past access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message.(Supplementary Note 56) A method performed by a reader, comprising: transmitting a first type access occasion initiation message, wherein the first type access occasion initiation message is transmitted to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, and the first type access occasion initiation message includes a first parameter for identifying the access occasion initiated by the first type access occasion initiation message, or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message. (Supplementary Note 57) A program causing a computer to perform a method for a reader, the method comprising transmitting a first type access occasion initiation message, the first type access occasion initiation message being transmitted to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, the first type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first type access occasion initiation message, or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message.(Supplementary Note 58) An Ambient Internet of Things (AIoT) device comprising: means for including or adding a predetermined end marker or postamble to a D2R message transmitted in an access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message, if a Device to reader (D2R) transmission is completed within the access occasion; and means for not including or adding the end marker or postamble to the D2R message, the PDU, or the physical channel, if a D2R transmission is not completed within the access occasion and there is pending data. (Supplementary Note 59) The AIoT device according to Supplementary Note 58, wherein the size of the D2R message, the length of the PDU, the length of the physical channel, the length of the transmission duration of the physical channel, or the length of the access occasion is a predefined fixed value. (Supplementary Note 60) A method performed by an Ambient Internet of Things (AIoT) device, comprising: if a Device to reader (D2R) transmission is completed within an access occasion, including or adding a predetermined end marker or postamble to a D2R message transmitted in the access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message; and if a D2R transmission is not completed within the access occasion and there is pending data, not including or adding the end marker or postamble to the D2R message, the PDU, or the physical channel.(Supplementary Note 61) A program for causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, comprising: if a Device to reader (D2R) transmission is completed within an access occasion, including or adding a predetermined end marker or postamble to a D2R message transmitted in the access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message; and if a D2R transmission is not completed within the access occasion and there is pending data, not including or adding the end marker or postamble to the D2R message, the PDU, or the physical channel. (Supplementary Note 62) An Ambient Internet of Things (AIoT) device, comprising: means for receiving an access occasion start message for starting one of a plurality of access occasions in a paging round started by an initial trigger or a paging message, the access occasion start message including information indicating the order of a current access occasion started by the access occasion start message within the plurality of access occasions. (Supplementary Note 63) The AIoT device according to Supplementary Note 62, further comprising: means for recognizing the order of the current access occasion among the plurality of access occasions based on the information. (Supplementary Note 64) The AIoT device according to Supplementary Note 62 or 63, further comprising: means for updating a counter for determining the arrival of an access occasion transmitted by the AIoT device by decrementing a number corresponding to the current access occasion from an initial value of the counter. (Supplementary Note 65) The AIoT device according to any one of Supplements 62 to 64, wherein the information is a serial number or index of the current access occasion.(Supplementary Note 66) A method performed by an Ambient Internet of Things (AIoT) device, comprising receiving an access occasion initiation message for initiating one of a plurality of access occasions in a paging round initiated by an initial trigger or a paging message, the access occasion initiation message including information indicating the order of a current access occasion initiated by the access occasion initiation message within the plurality of access occasions. (Supplementary Note 67) A program causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, comprising receiving an access occasion initiation message for initiating one of a plurality of access occasions in a paging round initiated by an initial trigger or a paging message, the access occasion initiation message including information indicating the order of a current access occasion initiated by the access occasion initiation message within the plurality of access occasions. (Supplementary Note 68) A reader according to Supplementary Note 68, comprising means for transmitting an access occasion initiation message for initiating one of a plurality of access occasions in a paging round initiated by an initial trigger or a paging message, the access occasion initiation message including information indicating an order of a current access occasion initiated by the access occasion initiation message within the plurality of access occasions. (Supplementary Note 69) The reader according to Supplementary Note 68, wherein the information causes an Ambient Internet of Things (AIoT) device to recognize an order of the current access occasion within the plurality of access occasions based on the information.(Supplementary Note 70) The reader of Supplementary Note 68 or 69, wherein the information causes an Ambient Internet of Things (AIoT) device to update a counter for determining the arrival of an access occasion transmitted by the AIoT device by decrementing a number corresponding to the current access occasion from an initial value of the counter. (Supplementary Note 71) The reader of any one of Supplementary Notes 68 to 70, wherein the information is a serial number or index of the current access occasion. (Supplementary Note 72) A method performed by a reader, comprising: transmitting an access occasion start message for starting one of multiple access occasions in a paging round started by an initial trigger or a paging message, wherein the access occasion start message includes information indicating the order of the current access occasion started by the access occasion start message within the multiple access occasions. (Supplementary Note 73) A program that causes a computer to perform a method for a reader, comprising sending an access occasion initiation message to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, wherein the access occasion initiation message includes information indicating the order of the current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

[0210] This application claims priority based on Japanese Patent Application No. 2024-129699, filed August 6, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0211] 1 AIoT device 2 Base station 3 Radio access network 4 Core network 5 Intermediate node 6 Assist node 8 Reader 2504 Controller 2505 Memory 2604 Processor 2605 Memory 2606 Modules 2703 Baseband processor 2704 Application processor 2706 Memory 2707 Modules

Claims

1. An Ambient Internet of Things (AIoT) device comprising: means for receiving a first reader to device (R2D) message; and means for transmitting a device to reader (D2R) message in response to the first R2D message, wherein a size of the D2R message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion on which the physical channel is transmitted is a predefined fixed value.

2. The AIoT device of claim 1, wherein the first R2D message does not include a field indicating the size of the D2R message, the length of the PDU, the length of the physical channel, the length of the transmission duration of the physical channel, or the length of the access occasion.

3. The AIoT device of claim 1 or 2, wherein the first R2D message includes one or more common fields and one or more individual fields, each common field being a field that is included in multiple types of R2D messages, and each individual field being a field that is included in a particular type of R2D message but not in other types of R2D messages, and the one or more common fields include a field that indicates the message type of the first R2D message.

4. The AIoT device of claim 3, wherein the first R2D message is a paging message or an initial trigger message, and the one or more individual fields include a field indicating a parameter for specifying the number of multiple access occasions within one paging round initiated by the first R2D message.

5. The AIoT device of claim 3, wherein the first R2D message is an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, and the one or more individual fields include a field indicating parameters for identifying the access occasion initiated by the first R2D message.

6. The AIoT device of claim 3, wherein the first R2D message is an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, and the one or more individual fields include parameters for identifying an AIoT device that should respond to the access occasion initiated by the first R2D message.

7. The AIoT device of claim 6, wherein the parameter indicates a random value or a temporary device identifier sent by the AIoT device in a previous access occasion within the paging round.

8. A method performed by an Ambient Internet of Things (AIoT) device, comprising: receiving a first reader to device (R2D) message; and transmitting a device to reader (D2R) message in response to the first R2D message; wherein a size of the D2R message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion on which the physical channel is transmitted is a predefined fixed value.

9. A program causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, comprising: receiving a first reader to device (R2D) message; and transmitting a device to reader (D2R) message in response to the first R2D message; wherein the size of the D2R message, the length of a Protocol Data Unit (PDU) containing the D2R message, the length of a physical channel carrying the D2R message, the length of a transmission duration of the physical channel, or the length of an access occasion over which the physical channel is transmitted are predefined fixed values.

10. A reader comprising: means for transmitting a first reader to device (R2D) message; and means for receiving a device to reader (D2R) message transmitted by an Ambient Internet of Things (AIoT) device in response to the first R2D message, wherein a size of the D2R message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted is a predefined fixed value.

11. The reader of claim 10, wherein the first R2D message does not include a field indicating the size of the D2R message, the length of the PDU, the length of the physical channel, the length of the transmission duration of the physical channel, or the length of the access occasion.

12. The reader of claim 10 or 11, wherein the first R2D message includes one or more common fields and one or more individual fields, each common field being a field that is included in multiple types of R2D messages, and each individual field being a field that is included in a particular type of R2D message but not in other types of R2D messages, and the one or more common fields include a field that indicates the message type of the first R2D message.

13. The reader of claim 12, wherein the first R2D message is a paging message or an initial trigger message, and the one or more individual fields include a field indicating a parameter for specifying the number of multiple access occasions within one paging round initiated by the first R2D message.

14. The reader of claim 12, wherein the first R2D message is an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or paging message, and the one or more individual fields include a field indicating parameters for identifying the access occasion initiated by the first R2D message.

15. The reader of claim 12, wherein the first R2D message is an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, and the one or more individual fields include parameters for identifying an AIoT device that should respond to the access occasion initiated by the first R2D message.

16. The reader of claim 15, wherein the parameter indicates a random value or a temporary device identifier sent by the AIoT device in a previous access occasion within the paging round.

17. A method performed by a reader, comprising: sending a first reader to device (R2D) message; and receiving a device to reader (D2R) message sent by an Ambient Internet of Things (AIoT) device in response to the first R2D message, wherein a size of the D2R message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion on which the physical channel is transmitted is a predefined fixed value.

18. A program causing a computer to perform a method for a reader, the method comprising: sending a first reader to device (R2D) message; and receiving a device to reader (D2R) message sent by an Ambient Internet of Things (AIoT) device in response to the first R2D message, wherein the size of the D2R message, the length of a Protocol Data Unit (PDU) containing the D2R message, the length of a physical channel carrying the D2R message, the length of a transmission duration of the physical channel, or the length of an access occasion over which the physical channel is transmitted are predefined fixed values.

19. An AIoT device comprising: means for receiving a first reader to device (R2D) message, wherein the first R2D message includes a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be sent in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted; and means for transmitting the D2R message in accordance with the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter.

20. The AIoT device of claim 19, wherein the first R2D message includes one or more common fields and one or more individual fields, each common field being a field that is included in multiple types of R2D messages, and each individual field being a field that is included in a particular type of R2D message but not in other types of R2D messages, and the first field is one of the one or more common fields.

21. The AIoT device of claim 19 or 20, wherein the first R2D message is a paging message or an initial trigger message for initiating a paging round including multiple access occasions.

22. The AIoT device of claim 19 or 20, wherein the first R2D message is an access occasion initiation message for initiating one of multiple access occasions within a paging round initiated by an initial trigger or a paging message.

23. A method performed by an AIoT device, comprising: receiving a first reader to device (R2D) message, wherein the first R2D message includes a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be transmitted in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted; and transmitting the D2R message in accordance with the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter.

24. A program for causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, comprising: receiving a first reader to device (R2D) message, wherein the first R2D message includes a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be sent in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion in which the physical channel is transmitted; and transmitting the D2R message in accordance with the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion specified based on the parameter.

25. A reader, comprising: means for transmitting a first reader to device (R2D) message, the first R2D message including a first field indicating parameters for specifying a size of a device to reader (D2R) message to be transmitted by an Ambient Internet of Things (AIoT) device in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted.

26. The reader of claim 25, further comprising means for receiving the D2R message transmitted by the AIoT device according to the size, length of the PDU, length of the physical channel, length of the transmission duration, or length of the access occasion, determined based on the parameters.

27. The reader of claim 25 or 26, wherein the first R2D message includes one or more common fields and one or more individual fields, each common field being a field that is included in multiple types of R2D messages, and each individual field being a field that is included in a particular type of R2D message but not in other types of R2D messages, and the first field is one of the one or more common fields.

28. The reader of any one of claims 25 to 27, wherein the first R2D message is a paging message or an initial trigger message for initiating a paging round including multiple access occasions.

29. A reader as described in any one of claims 25 to 27, wherein the first R2D message is an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or paging message.

30. A method performed by a reader, comprising: transmitting a first reader to device (R2D) message, the first R2D message including a first field indicating parameters for specifying a size of a device to reader (D2R) message to be sent by an Ambient Internet of Things (AIoT) device in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted.

31. A program causing a computer to perform a method for a reader, comprising transmitting a first reader to device (R2D) message, the first R2D message including a first field indicating a parameter for specifying a size of a device to reader (D2R) message to be sent by an Ambient Internet of Things (AIoT) device in response to receiving the first R2D message, a length of a Protocol Data Unit (PDU) containing the D2R message, a length of a physical channel carrying the D2R message, a length of a transmission duration of the physical channel, or a length of an access occasion over which the physical channel is transmitted.

32. An Ambient Internet of Things (AIoT) device, comprising: means for receiving a first type access occasion initiation message, wherein the first type access occasion initiation message is transmitted to initiate one of a plurality of access occasions in a paging round initiated by an initial trigger message or a paging message; and the first type access occasion initiation message includes a first parameter for identifying the access occasion initiated by the first type access occasion initiation message, or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message.

33. The AIoT device of claim 32, wherein the first type access occasion initiation message includes the second parameter.

34. The AIoT device of claim 33, wherein the second parameter indicates a random value or a temporary device identifier transmitted by the AIoT device in a previous access occasion within the paging round.

35. The AIoT device of claim 32, wherein the first type access occasion initiation message includes the first parameter.

36. The AIoT device of any one of claims 32 to 35, further comprising means for operating a counter for determining the arrival of its own access occasion, wherein the receiving means is configured to receive a second type access occasion start message that does not include the first parameter or the second parameter, and the operating means is configured to: decrement the counter when receiving the second type access occasion start message; and not decrement the counter when receiving the first type access occasion start message.

37. The AIoT device of any one of claims 32 to 36, wherein the access occasion initiated by the first type access occasion initiation message is an additional or supplementary access occasion separate from the multiple access occasions specified by the initial trigger message or the paging message.

38. The AIoT device described in any one of claims 32 to 37, wherein the first type access occasion initiation message is transmitted by the reader when the reader was unable to successfully receive a device to reader (D2R) transmission by the AIoT device in a previous access occasion.

39. The AIoT device of claim 38, further comprising means for retransmitting data transmitted in the previous access occasion in the access occasion initiated by the first type access occasion initiation message.

40. The AIoT device described in any one of claims 32 to 37, wherein the first type access occasion initiation message is sent by the reader when the reader recognizes that there is pending data that could not be sent in a device to reader (D2R) transmission by the AIoT device in a previous access occasion.

41. The AIoT device of claim 40, further comprising: means for transmitting the pending data in an access occasion initiated by the first type access occasion initiation message.

42. The AIoT device of claim 40 or 41, further comprising means for notifying the reader of the presence of the pending data by not including or not adding a predetermined end marker or postamble to the D2R message transmitted in the past access occasion, the Protocol Data Unit (PDU) containing the D2R message, or the physical channel carrying the D2R message.

43. A method performed by an Ambient Internet of Things (AIoT) device, comprising receiving a first type access occasion initiation message, wherein the first type access occasion initiation message is sent to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, and the first type access occasion initiation message includes a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message.

44. A program causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, the method comprising receiving a first type access occasion initiation message, the first type access occasion initiation message being sent to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, the first type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message.

45. A reader comprising: means for transmitting a first type access occasion initiation message, wherein the first type access occasion initiation message is transmitted to initiate one of a plurality of access occasions in a paging round initiated by an initial trigger message or a paging message, and wherein the first type access occasion initiation message includes a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message.

46. ​​The reader of claim 45, wherein the first type access occasion initiation message includes the second parameter.

47. The reader of claim 46, wherein the second parameter indicates a random value or a temporary device identifier sent by the AIoT device in a previous access occasion within the paging round.

48. The reader of claim 45, wherein the first type of access occasion initiation message includes the first parameter.

49. The reader of any one of claims 45 to 48, wherein the transmitting means is configured to transmit a second type access occasion start message that does not include either the first parameter or the second parameter, the second type access occasion start message causing the AIoT device to decrement a counter for determining the arrival of its own access occasion when receiving the second type access occasion start message, and the first type access occasion start message causing the AIoT device not to decrement the counter when receiving the first type access occasion start message.

50. A reader as described in any one of claims 45 to 49, wherein the access occasion initiated by the first type access occasion initiation message is an additional or supplementary access occasion separate from the plurality of access occasions specified by the initial trigger message or the paging message.

51. A reader as described in any one of claims 45 to 50, wherein the transmitting means is configured to transmit the first type of access occasion start message when the reader was unable to successfully receive a device to reader (D2R) transmission by the AIoT device in a previous access occasion.

52. The reader of claim 51, wherein the first type access occasion initiation message causes the AIoT device to retransmit data transmitted in the previous access occasion in the access occasion initiated by the first type access occasion initiation message.

53. A reader as described in any one of claims 45 to 50, wherein the transmitting means is configured to transmit the first type of access occasion start message when the reader recognizes that there is pending data that could not be transmitted in a device to reader (D2R) transmission by the AIoT device in a previous access occasion.

54. The reader of claim 53, wherein the first type access occasion initiation message causes the AIoT device to transmit the pending data in an access occasion initiated by the first type access occasion initiation message.

55. The reader of claim 53 or 54, further comprising means for detecting the presence of the pending data based on the absence of a predetermined end marker or postamble in or attached to a D2R message transmitted in the previous access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message.

56. A method performed by a reader, comprising: transmitting a first type access occasion initiation message, wherein the first type access occasion initiation message is transmitted to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, and the first type access occasion initiation message includes a first parameter for identifying the access occasion initiated by the first type access occasion initiation message or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond with the access occasion initiated by the first type access occasion initiation message.

57. A program causing a computer to perform a method for a reader, the method comprising transmitting a first type access occasion initiation message, the first type access occasion initiation message being transmitted to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger message or a paging message, the first type access occasion initiation message including a first parameter for identifying the access occasion initiated by the first type access occasion initiation message, or a second parameter for specifying an Ambient Internet of Things (AIoT) device that should respond to the access occasion initiated by the first type access occasion initiation message.

58. An Ambient Internet of Things (AIoT) device comprising: means for including or adding a predetermined end marker or postamble to a Device to reader (D2R) message transmitted in an access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message, if a Device to reader (D2R) transmission is completed within the access occasion; and means for not including or adding the end marker or postamble to the D2R message, the PDU, or the physical channel if a D2R transmission is not completed within the access occasion and there is pending data.

59. The AIoT device of claim 58, wherein the size of the D2R message, the length of the PDU, the length of the physical channel, the length of the transmission duration of the physical channel, or the length of the access occasion is a predefined fixed value.

60. A method performed by an Ambient Internet of Things (AIoT) device, comprising: if a Device to reader (D2R) transmission is completed within an access occasion, including or adding a predetermined end marker or postamble to a D2R message transmitted in the access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message; and if a D2R transmission is not completed within the access occasion and there is pending data, not including or adding the end marker or postamble to the D2R message, the PDU, or the physical channel.

61. A program for causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, comprising: if a Device to reader (D2R) transmission is completed within an access occasion, including or adding a predetermined end marker or postamble to a D2R message transmitted in the access occasion, a Protocol Data Unit (PDU) containing the D2R message, or a physical channel carrying the D2R message; and if a D2R transmission is not completed within the access occasion and there is pending data, not including or adding the end marker or postamble to the D2R message, the PDU, or the physical channel.

62. An Ambient Internet of Things (AIoT) device, comprising: means for receiving an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, wherein the access occasion initiation message includes information indicating the order of a current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

63. The AIoT device of claim 62, further comprising: means for recognizing the order of the current access occasion within the plurality of access occasions based on the information.

64. The AIoT device of claim 62 or 63, further comprising means for updating a counter for determining the arrival of an access occasion transmitted by the AIoT device by decrementing a number corresponding to the current access occasion from the initial value of the counter.

65. An AIoT device as described in any one of claims 62 to 64, wherein the information is a serial number or index of the current access occasion.

66. A method performed by an Ambient Internet of Things (AIoT) device, comprising receiving an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, wherein the access occasion initiation message includes information indicating the order of the current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

67. A program causing a computer to perform a method for an Ambient Internet of Things (AIoT) device, comprising receiving an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, wherein the access occasion initiation message includes information indicating the order of the current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

68. A reader comprising means for transmitting an access occasion initiation message for initiating one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, wherein the access occasion initiation message includes information indicating the order of the current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

69. The reader of claim 68, wherein the information causes an Ambient Internet of Things (AIoT) device to recognize the order of the current access occasion within the plurality of access occasions based on the information.

70. The reader of claim 68 or 69, wherein the information causes the Ambient Internet of Things (AIoT) device to update a counter for determining the arrival of an access occasion sent by the AIoT device by decrementing the counter's initial value by a number corresponding to the current access occasion.

71. A reader according to any one of claims 68 to 70, wherein the information is a serial number or index of the current access occasion.

72. A method performed by a reader, comprising: transmitting an access occasion initiation message to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, wherein the access occasion initiation message includes information indicating the order of the current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

73. A program causing a computer to perform a method for a reader, the method comprising sending an access occasion initiation message to initiate one of a plurality of access occasions within a paging round initiated by an initial trigger or a paging message, the access occasion initiation message including information indicating the order of the current access occasion initiated by the access occasion initiation message within the plurality of access occasions.

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