Method, communication device, and infrastructure equipment

Abstract

A method may be provided for operating a communication device configured to transmit signals to and / or receive signals from a wireless communication network via a wireless radio interface provided by the wireless communication network, the method including receiving a paging message from the wireless communication network while the communication device is operating in an inactive state, the paging message indicating that the wireless communication network is to transmit a downlink small data transmission, SDT, to the communication device, determining whether one or more predetermined conditions for receiving the downlink SDT are met in response to receiving the paging message, transmitting an indication of whether the one or more predetermined conditions are met to the wireless communication network, and receiving the downlink SDT from the wireless communication network in a manner dependent on whether the one or more predetermined conditions are met.

Description

[Technical field]

[0001] The present disclosure relates to communication devices, infrastructure equipment and methods for efficient reception of data by communication devices in a wireless communication network.

[0002] This application claims Paris Convention priority from European Patent Application No. EP22164839.7, filed March 28, 2022, the contents of which are incorporated herein by reference.

[0003] The "Background" description provided herein is intended to generally indicate the context of the present disclosure. The work of the present named inventors to the extent described in this Background section, and aspects of the present specification that may not qualify as prior art at the time of filing, are not admitted expressly or impliedly as prior art against the present invention. [Background technology]

[0004] Latest generation mobile telecommunications systems, such as those based on the UMTS and Long Term Evolution (LTE) architectures defined by 3GPP, can support a wider range of services than the simple voice and messaging services offered by previous generation mobile telecommunications systems. For example, the improved air interface and enhanced data rates offered by LTE systems allow users to enjoy high data rate applications such as mobile video streaming and mobile video conferencing that were previously only available over fixed line data connections. As such, there is a strong demand for the deployment of such networks, and the coverage areas of such networks, i.e., the geographic locations where the networks can be accessed, are expected to continue to expand rapidly.

[0005] Future wireless communication networks are expected to routinely and efficiently support communication with an ever-increasing range of devices associated with a wider range of data traffic profiles and types than existing systems are optimized to support. For example, future wireless communication networks are expected to efficiently support communication with devices including reduced complexity devices, machine type communication (MTC) devices, high resolution video displays, virtual reality headsets, etc. Some of these different types of devices may be deployed in very large quantities, e.g., low complexity devices to support the "Internet of Things," and may typically be associated with the transmission of relatively small amounts of data with relatively high latency tolerance. Other types of devices, e.g., supporting high definition video streaming, may be associated with the transmission of relatively large amounts of data with relatively low latency tolerance. Other types of devices, e.g., used for autonomous driving communications and other critical applications, may be characterized by data that must be transmitted over the network with low latency and high reliability. Also, one device type may be associated with different traffic profiles / characteristics depending on the application it runs on. For example, considerations for efficiently supporting data exchange with a smartphone may be different when it is running a video streaming application (high downlink data) versus an Internet browsing application (sporadic uplink and downlink data) or when it is being used for voice communications by emergency responders in an emergency scenario (data subject to stringent reliability and latency requirements).

[0006] In this regard, it is anticipated that future wireless communications networks, e.g., what may be referred to as 5G or New Radio (NR) systems / New Radio Access Technology (RAT) systems, as well as future iterations / releases of existing systems, will be desired to efficiently support connectivity for a wide range of devices associated with different applications and different characteristic data traffic profiles and requirements.

[0007] The increasing use of different types of network infrastructure equipment and terminal devices associated with different traffic profiles creates new challenges for efficiently handling communications in wireless communications systems that must be addressed. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] European Patent Application Publication No. EP3834524 [Non-patent literature]

[0009] [Non-Patent Document 1] Holma H. ​​and Toskala A, "LTE for UMTS OFDMA and SC-FDMA based radio access", John Wiley and Sons, 2009 [Non-Patent Document 2] RP-192330, "New work item: 2-step RACH for NR," ZTE Corporation, 3GPP TSG RAN Meeting #85 [Non-Patent Document 3] RP-192324, "Revised WID: Support of NR Industrial Internet of Things (IoT)," Nokia, Nokia Shanghai Bell, 3GPP TSG RAN Meeting #85 [Non-Patent Document 4] RP-191575, "NR-based Access to Unlicensed Spectrum," Qualcomm, Inc., 3GPP TSG RAN Meeting #84 [Non-Patent Document 5] RP- 193252, "New Work Item on NR small data transmission in INACTIVE state," ZTE Corporation, 3GPP TSG RAN Meeting #86 [Non-Patent Document 6] RP -213583, "New WI: Mobile Terminated-Small Data Transmission (MT-SDT) for NR", 3GPP [Non-Patent Document 7] R2-2102707, "Report from email discussion [POST113-e]

[0501] [SDT] Selection criteria and overall Procedure," Samsung, 3GPP RAN WG2 Meeting #113bis-e Summary of the Invention [Means for solving the problem]

[0010] The present disclosure may help address and / or alleviate at least some of the problems discussed above.

[0011] An embodiment of the present technology may provide a method of operating a communication device configured to transmit signals to and / or receive signals from a wireless communication network via a wireless radio interface provided by the wireless communication network, the method including receiving a paging message from the wireless communication network while the communication device is operating in an inactive state, the paging message indicating that the wireless communication network is to transmit a downlink small data transmission, SDT, to the communication device, determining whether one or more predetermined conditions for receiving the downlink SDT are met in response to receiving the paging message, transmitting an indication of whether the one or more predetermined conditions are met to the wireless communication network, and receiving the downlink SDT from the wireless communication network in a manner dependent on whether the one or more predetermined conditions are met.

[0012] In addition to methods of operating communication devices, embodiments of the present technology relate to communication devices, infrastructure equipment, methods of operating such infrastructure equipment, circuitry for such communication devices and infrastructure equipment, wireless communication systems, computer programs, and non-transitory computer-readable storage media that enable more efficient use of radio resources by communication devices.

[0013] Various aspects and features of the present disclosure are defined in the appended claims.

[0014] It is to be understood that both the foregoing general description and the following detailed description are exemplary of the present technology and are not restrictive. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0015] A more complete understanding of the present disclosure and many of the attendant advantages will be readily obtained as the same becomes better understood by reference to the following detailed description, taken in connection with the accompanying drawings, in which like reference numerals designate the same or corresponding parts throughout the several views, and in which: [Brief description of the drawings]

[0016] [Figure 1] 1 illustrates generally certain aspects of an LTE-type wireless telecommunications system that may be configured to operate in accordance with certain embodiments of the present disclosure; [Diagram 2] 1 illustrates generally certain aspects of a new Radio Access Technology (RAT) wireless telecommunications system that may be configured to operate in accordance with certain embodiments of the present disclosure; [Diagram 3] FIG. 1 is a schematic block diagram of example infrastructure equipment and communication devices that may be configured to operate in accordance with certain embodiments of the present disclosure. [Figure 4A] FIG. 4A illustrates how uplink small data transmission (SDT) may be performed by a user equipment (UE) using a random access (RACH) scheme while the UE is in an inactive state. [Figure 4B] FIG. 4B illustrates how uplink small data transmission (SDT) may be performed by a user equipment (UE) using a random access (RACH) scheme while the UE is in an inactive state. [Diagram 5] 1 shows a partially schematic, partially message flow diagram of a wireless communication system including communication devices and infrastructure equipment, in accordance with an embodiment of the present technology; [Figure 6] 1 is a flow diagram illustrating a first example process of communication in a communication system according to an embodiment of the present technology. [Figure 7] 4 is a flow diagram illustrating a second example process of communication in a communication system according to an embodiment of the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Long Term Evolution Advanced Wireless Access Technology (4G) Figure 1 is a schematic diagram illustrating some basic features of a mobile telecommunications network / system 6 that generally operates according to LTE principles, but may support other radio access technologies and be adapted to implement the embodiments of the present disclosure described herein. Certain aspects of the various elements of Figure 1 and their respective modes of operation are well known and defined in the relevant standards administered by the 3GPP (RTM) body, and are also described in many books on the subject, such as "3GPP LTE-2002.11.0 ...

[0018] The network 6 includes a number of base stations 1 connected to a core network 2. Each base station provides a coverage area 3 (i.e., a cell) over which data can be communicated to and from communication devices 4. Although each base station 1 is shown in Figure 1 as a single entity, those skilled in the art will appreciate that some of the functions of a base station may be performed by disparate interconnected elements, such as antennas (or aerials), remote radio heads, amplifiers, etc. Collectively, one or more base stations may form a radio access network.

[0019] Data is transmitted from the base stations 1 to the communication devices 4 in their respective coverage areas 3 via a wireless downlink (DL). Data is transmitted from the communication devices 4 to the base stations via a wireless uplink (UL). The core network 2 routes data to and from the communication devices 4 via their respective base stations 1 and provides functions such as authentication, mobility management, charging, etc. The terminal devices may also be referred to as mobile stations, user equipment (UE), user terminals, mobile radios, communication devices, etc. Services provided by the core network 2 may include connectivity to the Internet or external telephone services. The core network 2 may further track the location of the communication devices 4 so that it can efficiently contact (i.e., page) the communication devices 4 for transmitting downlink data towards them.

[0020] A base station, an example of network infrastructure equipment, may also be referred to as a transceiver station, Node B, e-Node B, eNB, g-Node B, gNB, etc. In this regard, different terminology is often associated with different generations of wireless telecommunications systems for elements that provide substantially equivalent functionality. However, certain embodiments of the present disclosure may be equally implemented in different generations of wireless telecommunications systems, and for simplicity, a particular terminology may be used regardless of the underlying network architecture. That is, the use of a particular terminology in connection with a particular example embodiment is not intended to indicate that these implementations are limited to a particular generation of networks that may be most relevant to that particular terminology.

[0021] New Wireless Access Technology (5G) 3GPP completed the basic version of 5G, known as New Radio Access Technology (NR), in Rel-15, which was further enhanced in Rel-16 to incorporate new features such as the two-step RACH procedure (Non-Patent Document 2), Industrial Internet of Things (IIoT) (Non-Patent Document 3), and NR-based access to unlicensed spectrum (NR-U) (Non-Patent Document 4).

[0022] Further enhancements have been agreed in Rel-17, such as small data transmission (SDT) in the uplink while the transmitting UE is in RRC_INACTIVE state, multicast broadcast service (MBS), and positioning enhancements. Referring to Non-Patent Document 5, the following use cases are considered as specific examples of mobile originated small data transmission (MO SDT) and infrequent data traffic: Smartphone application: Traffic from instant messaging services Heartbeat / keep-alive traffic from IM / email clients and other applications Push notifications from various applications Non-smartphone applications: Traffic from wearable devices (e.g., periodic positioning information) Sensors (e.g. industrial wireless sensor networks transmitting temperature or pressure measurements periodically or in an event-triggered manner) Smart meters and smart meter networks that periodically transmit meter readings.

[0023] Furthermore, based on the aforementioned Non-Patent Document 5, uplink small data transmission is enabled for UEs in RRC_INACTIVE state (i.e., without the UE transitioning to a fully connected state with the network) to reduce signaling overhead and power consumption at the UE, and mainly for infrequent data traffic. SDT transmission in uplink for UEs in RRC_INACTIVE state has been agreed for both RACH-based schemes (2-step and 4-step RACH), called Random Access SDT (RA-SDT), and Configuration Grant (CG)-based scheme (CG-SDT), which will be described in detail later. This includes a general procedure for enabling user plane data transmission of small data packets in uplink in inactive state (e.g., using either MsgA in the 2-step RACH procedure or Msg3 in the 4-step RACH procedure), and enabling flexible payload sizes larger than currently possible Rel-16 Common Control Channel (CCCH) message sizes for transmitting small data in MsgA or Msg3 for UEs in RRC_INACTIVE state to support user plane data transmission in uplink.

[0024] While support for SDT (i.e., MO SDT) in the uplink is still under development in Rel-17 (see, for example, Non-Patent Document 5), in Rel-18, discussions have also started on the need for Mobile Terminated (MT) transmission in the downlink for SDT, for example for positioning services and infrequent small data reception for UEs in RRC_INACTIVE state (Non-Patent Document 6). With reference to Non-Patent Document 6, the justification and objectives for MT SDT in Rel-18 are presented below: Justification - In Rel-17, MO-SDT was specified to enable small packet transmissions for UL-directed packets. For DL, MT-SDT (i.e. DL trigger small data) provides similar benefits, e.g. for positioning, by reducing signaling overhead and UE power consumption by not transitioning to RRC_CONNECTED, and by enabling faster transmission of (small and infrequent) packets, reducing latency. ·the purpose Specification of support for paging trigger SDT (MT-SDT) MT-SDT trigger mechanism for UE supporting RA-SDT and CG-SDT as UL responses in RRC_INACTIVE MT-SDT procedure for first DL data reception and subsequent UL / DL data transmission in RRC_INACTIVE

[0025] NR configuration example The NR radio access system employs Orthogonal Frequency Division Multiple Access (OFDMA), where different users are scheduled simultaneously on different subsets of subcarriers. However, OFDMA requires strict synchronization in uplink transmissions to achieve orthogonality of transmissions from different users. In essence, uplink transmissions from all users must arrive at the gNB receiver at the same time (i.e., synchronized). Therefore, UEs farther from the gNB must transmit earlier than UEs closer to the gNB due to different RF propagation delays. In NR, timing advance commands are applied to control the uplink transmission timing of individual UEs, mainly for the Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), and Sounding Reference Signal (SRS). The timing advance typically consists of twice the one-way propagation delay between the UE and the gNB, and therefore represents both the downlink and uplink delays.

[0026] An example of the configuration of a wireless communication network using some of the terminology proposed and used in NR and 5G is shown in FIG. 2. In FIG. 2, multiple transmission / reception points (TRP) 10 are connected to distributed control units (DUs) 41, 42 by connection interfaces represented by lines 16. Each TRP 10 is arranged to transmit and receive signals over a radio access interface (i.e., a radio interface for wireless access) within the radio frequency bandwidth available in the wireless communication network. Thus, within the range for wireless communication over the wireless access interface, each TRP 10 forms a cell of the wireless communication network, as represented by a circle 12. In this way, a wireless communication device 14 that is within the wireless communication range provided by the cell 12 can transmit and receive signals to and from the TRP 10 over the wireless access interface. Each distributed unit 41, 42 is connected to a central unit (CU) 40 (sometimes called a control node) via an interface 46. The central unit 40 is then connected to a core network 20 that includes all other functions necessary for data transmission to communicate to and from the wireless communication devices, and the core network 20 may be connected to other networks 30.

[0027] The elements of the wireless access network illustrated in Figure 2 may operate in a manner similar to the corresponding elements of the LTE network as described with respect to the example of Figure 1. It will be understood that operational aspects of the telecommunications network depicted in Figure 2, and other networks described herein in accordance with embodiments of the present disclosure that are not specifically described (e.g., those relating to particular communication protocols and physical channels for communicating between different elements), may be implemented in accordance with any known technique, e.g., in accordance with approaches currently used to implement such operational aspects of wireless telecommunications systems, e.g., in accordance with relevant standards.

[0028] The TRP 10 of FIG. 2 may have functionality corresponding in part to a base station or eNodeB of an LTE network. Similarly, the communication device 14 may have functionality corresponding to a UE device 4 known for operation in an LTE network. It will therefore be understood that the operational aspects of the new RAT network (e.g., in relation to specific communication protocols and physical channels for communicating between different elements) may differ from those known from LTE or other known mobile telecommunications standards. However, it will also be understood that each of the core network components, base stations, and communication devices of the new RAT network are functionally similar to the core network components, base stations, and communication devices of an LTE wireless communication network, respectively.

[0029] In terms of broad top-level functionality, the core network 20 connected to the new RAT telecommunication system depicted in Fig. 2 can be broadly considered to correspond to the core network 2 depicted in Fig. 1, and each central unit 40 and their associated distributed units / TRPs 10 can be broadly considered to provide functionality corresponding to the base stations 1 of Fig. 1. The term network infrastructure equipment / access nodes may be used to encompass these elements as well as traditional base station type elements of wireless telecommunication systems. The responsibility for scheduling transmissions scheduled on the air interface between each distributed unit and the communication device lies with the control node / central unit and / or the distributed units / TRPs, depending on the application at hand. In Fig. 2, a communication device 14 is depicted within the coverage area of ​​a first communication cell 12. This communication device 14 may therefore exchange signals with a first central unit 40 of the first communication cell 12 via one of the distributed units / TRPs 10 associated with the first communication cell 12.

[0030] Furthermore, it will be appreciated that FIG. 2 represents merely one example of a proposed architecture for a new RAT-based telecommunications system in which an approach consistent with the principles described herein may be employed, and that the functionality disclosed herein may also be applied in relation to wireless telecommunications systems having different architectures.

[0031] Accordingly, certain embodiments of the present disclosure described herein may be implemented in wireless telecommunications systems / networks according to a variety of different architectures, such as the exemplary architectures shown in Figures 1 and 2. Thus, it will be understood that the particular wireless telecommunications architecture in any given implementation is not of primary importance to the principles described herein. In this regard, certain embodiments of the present disclosure may be generally described in the context of communications between network infrastructure equipment / access nodes and communication devices, the particular nature of which will depend on the network infrastructure of the implementation at hand. For example, in some scenarios, the network infrastructure equipment / access nodes may include base stations, such as the LTE type base station 1 as shown in Figure 1, adapted to provide functionality in accordance with the principles described herein, and in other examples, the network infrastructure equipment may include a control unit / control node 40 and / or TRP 10 of the type shown in Figure 2, adapted to provide functionality in accordance with the principles described herein.

[0032] A more detailed view of some of the components of the network shown in Figure 2 is provided by Figure 3. In Figure 3, the TRP 10 as shown in Figure 2 includes, as a simplified representation, a wireless transmitter 30, a wireless receiver 32, and a controller or control processor 34 that may operate to control the transmitter 30 and the wireless receiver 32 to transmit and receive radio signals to one or more UEs 14 within the cell 12 formed by the TRP 10. As shown in Figure 3, an exemplary UE 14 is shown to include a corresponding transmitter 45, a receiver 48, and a controller 44 configured to control the transmitter 45 and the receiver 48 to transmit signals representing uplink (UL) data to a wireless communication network via a wireless access interface formed by the TRP 10, and to receive downlink (DL) data as signals transmitted by the transmitter 30 and received by the receiver 48 according to conventional operation.

[0033] The transmitters 30, 45 and receivers 32, 48 (as well as other transmitters, receivers and transceivers described in connection with examples and embodiments of the present disclosure) may include radio frequency filters and amplifiers as well as signal processing components and devices, for example, to transmit and receive wireless signals according to the 5G / NR standard. The controllers 34, 44 (as well as other controllers described in connection with examples and embodiments of the present disclosure) may be, for example, a microprocessor, a CPU, or a dedicated chipset, etc., configured to execute instructions stored in a computer-readable medium, such as a non-volatile memory. The processing steps described herein may be performed, for example, by a microprocessor in combination with a random access memory operating according to instructions stored in a computer-readable medium. The transmitters, receivers and controllers are shown in FIG. 3 as schematic separate elements for ease of representation. However, it will be appreciated that the functionality of these elements may be provided in a variety of different ways, for example, using one or more appropriately programmed programmable computers, or one or more appropriately configured application-specific integrated circuits / circuits / chips / chipsets. As will be appreciated, the infrastructure equipment / TRP / base station, as well as the UE / communication device, generally comprises various other elements related to its operational functionality.

[0034] 3, the TRP 10 also includes a network interface 47 that connects to the DU 42 via the physical interface 16. The network interface 47 thus provides a communication link for data and signaling traffic from the TRP 10 to the core network 20 via the DU 42 and the CU 40.

[0035] The interface 46 between the DU 42 and the CU 40 is known as the F1 interface, which may be a physical interface or a logical interface. The Fl interface 46 between the CU and the DU operates according to the specifications 3GPP TS 38.470 and 3GPP TS 38.473 and may be formed of optical fiber or other wired or wireless high bandwidth connections. In one example, the connection 16 from the TRP 10 to the DU 42 is via optical fiber. The connection between the TRP 10 and the core network 20 can generally be referred to as the backhaul, which consists of the interface 16 from the network interface 47 of the TRP 10 to the DU 42 and the Fl interface 46 from the DU 42 to the CU 40.

[0036] Mobile Originated Small Data Transmission (MO SDT) As mentioned, there are three schemes agreed by 3GPP for initiation of SDT transmission in the inactive mobile UE originated uplink. These are: - 4-step RACH-based scheme - Two-step RACH-based scheme -CG based scheme

[0037] Figure 4A shows an example of a 4-step RACH-based scheme and how such a scheme can initiate an MO SDT. When a UE has a UL SDT ready for transmission, it can initiate a 4-step RACH procedure, which includes the following steps, as shown in Figure 4A. The UE starts transmitting a Physical Random Access (PRACH) preamble, message 1, from the set of preambles allocated for SDT in the current cell (50). When the gNB receives the preamble, it identifies this as the start of SDT and responds with message 2. The gNB transmits message 2 (51) containing a UL timing alignment command and UL PUSCH scheduling for message 3. The UE receives Radio Resource Control (RRC) signaling (i.e., the RRCResumeRequest ), and if there is remaining space in the scheduled PUSCH, transmits message 3 containing the SDT data (52). Similar to the general 4-step RACH procedure, the gNB provides contention resolution (53) after the UE that transmitted the preamble in the first step 50 has been identified and confirmed. In this step 53, DL and UL feedback or acknowledgement is transmitted. For UL feedback received by the gNB from the UE in response to transmission of a DL PDSCH to the UE, a HARQ-ACK is transmitted on the cell-specific PUCCH resources configured in the system information (note however that from the third step 52 the UE is already UL synchronized). For DL ​​feedback received by the UE in response to transmission of UL message 3 in the third step 52, receipt of message 4 at the UE in a fourth step 53 is considered as a positive acknowledgement. After the fourth step 53, the UE is already identified by the network and UL synchronized. Therefore, if necessary, subsequent UL and DL SDT with dynamic scheduling can be performed while the UE remains in INACTIVE state (54). Once SDT is completed and neither the gNB nor the UE has small data to transmit, the gNB can choose to keep the UE in RRC_INACTIVE state by sending RRCRelease with suspend indication (55).

[0038] Figure 4B shows an example of a two-step RACH-based scheme and how such a scheme can initiate an MO SDT. When the UE has a UL SDT ready for transmission, the UE may initiate a two-step RACH procedure as shown in Figure 4B. The UE starts transmitting the PRACH preamble for SDT and the associated PUSCH msgA in the current cell (56). The PUSCH contains no RRC signaling (i.e., the PRACH preamble for SDT). RRC Resume Request ) and, if there is space remaining in the PUSCH, SDT data. · Similar to the general two-step RACH procedure, when the gNB receives msgA it identifies this as an SDT start (56) and responds with msgB (57) containing both a UL timing alignment command and a contention resolution where the UE that transmitted msgA in the first step is identified and acknowledged (56). In this step 57 DL and UL feedback or acknowledgement is transmitted. For UL feedback received by the gNB from the UE in response to a DL PDSCH transmitted from the gNB to that UE, a HARQ-ACK is transmitted from the UE on the cell specific PUCCH resources configured in the system information. For DL ​​feedback received by the UE from the gNB (56) in response to msgA transmitted by the UE, receipt of msgB (57) at the UE is considered a positive acknowledgment. After the second step 57, the UE is already identified by the network and the UL is synchronized. Therefore, the UE can perform subsequent UL and DL SDT with dynamic scheduling, if necessary, while remaining in INACTIVE state. Once SDT is completed and neither the gNB nor the UE has any small data to transmit, the UE will be switched to the UE with a suspend indication 59. RRC Release The gNB may choose to keep the UE in RRC_INACTIVE state by transmitting (59).

[0039] If a UE stays in the same cell for a certain period of time, it may be able to use pre-configured UL resources for data transmission while in INACTIVE state if the UE is UL synchronized. Therefore, in Rel-17, it is agreed that the network may configure dedicated CG PUSCH resources for SDT in a Dedicated Bandwidth Part (BWP) or in an initial BWP just before the UE transitions to RRC_INACTIVE state. The use of CG PUSCH resources is subject to several criteria, e.g., UL time alignment has not expired and DL Reference Signal Received Power (RSRP) has not changed significantly (e.g., the UL time alignment has not expired and the DL Reference Signal Received Power (RSRP) has not changed significantly (e.g., the UL time alignment has not changed significantly ...) (e.g., the UL time alignment has not changed significantly and the DL Reference Signal Received Power (RSRP) has not changed significantly). delta value). In addition, there is also a DL acknowledgement (i.e., explicit or implicit HARQ-ACK feedback) for the transmitted CG-SDT. Note that after the first transmission using CG PUSCH, the UE is also allowed to be scheduled on DL PDSCH (i.e., subsequent UL and DL SDT transmissions are possible).

[0040] In the current discussion of Rel-17 (Non-Patent Document 7), the high level procedure for selection between SDT and non-SDT procedures upon arrival of only UL data for an SDT enabled Data Radio Bearer (DRB) / Signaling Radio Bearer (SRB) is as follows: · If the CG-SDT criteria are met: The UE selects CG-SDT and initiates the SDT procedure. · Else, if the RA-SDT criteria are met: the UE selects RA-SDT and initiates the SDT procedure. · Otherwise: The UE initiates a non-SDT procedure.

[0041] The criteria for CG-SDT and RA-SDT specified in Non-Patent Document 7 are as follows: · A patient is considered to meet the CG-SDT criteria if all of the following conditions are met: The amount of available data is less than or equal to the data amount threshold of the SDT. RSRP is greater than or equal to a configured threshold. CG-SDT resources are configured and valid for the selected UL carrier. · The RA-SDT criteria are considered to be met if all of the following conditions are met: The amount of available data is less than or equal to the data amount threshold of the SDT. RSRP is greater than or equal to a configured threshold. A 4-step RA-SDT resource is configured on the selected UL carrier and the criteria for selecting a 4-step RA SDT are met, or a 2-step RA-SDT resource is configured on the selected UL carrier and the criteria for selecting a 2-step RA SDT are met.

[0042] Mobile Terminated Small Data Transmission (MT SDT) In Rel-17, development is still underway to support Small Data Transmission (SDT) for inactive uplink (aka Mobile Originated (MO) transmission), while in Rel-18 discussions have also started regarding the need for Mobile Terminated (MT) transmission on the downlink for SDT, e.g., for positioning services and infrequent small data reception for inactive UEs. Possible triggering mechanisms for MT-SDT (described in detail in co-pending European patent application Ser. No. 60 / 2009 / 023635, the contents of which are incorporated herein by reference) include: · Paging message to trigger SDT transmission in DL. · Specific dynamic DCI to trigger SDT transmission in DL. · Semi-Persistent Scheduling (SPS) configuration for triggering SDT transmissions in DL.

[0043] If a paging message is used to trigger SDT transmission to the UE, then when the UE receives such a paging trigger, it is clear that the UE first needs to synchronize with the network before receiving DL SDT data, because the UE needs to transmit HARQ-ACK feedback in uplink (e.g., via PUCCH) for the received DL SDT data, and needs to synchronize with the network to transmit the HARQ-ACK feedback.

[0044] The UE may respond to the network request / indication in the triggering paging message in different ways or using different procedures. One such way is that if the UE has already configured CG-SDT in the current cell, the UE may already be synchronized with the network and may immediately transmit a UL response (e.g., CCCH message) on CG resources to indicate successful reception of DL SDT data. Alternatively, if the UE is not configured with CG, the UE may trigger an SDT RACH procedure to synchronize with the network in the uplink. However, before performing a preferred UL response (e.g., transmission of HARQ-ACK feedback), the UE must check certain conditions upon receipt of the paging-triggered SDT. If one or more of these specific conditions are not met, the UE may not be able to perform a preferred UL response. That is, the network may not know if the SDT was successfully received and may determine that it needs to retransmit the SDT or may unnecessarily request the UE to transition to CONNECTED state. Both of these increase power usage and reduce efficiency at the UE.

[0045] Thus, when a UE receives a paging trigger for SDT transmission in the downlink (MT-SDT), the problem to be solved is how the UE should respond in the UL to an SDT paging trigger that depends on such conditions, so that the network can transmit the SDT in such a way that the UE can respond in the UL. Embodiments of the present technology provide a solution to this problem, related to both the conditions that the UE (operating in INACTIVE state) must check before responding to the network, and the procedure that the UE (operating in INACTIVE state) should follow if some of these conditions are not met.

[0046] DL SDT Procedures and Conditions for Inactive State 5 is a partial schematic, partial message flow diagram of a first wireless communication system including a communication device 101 and infrastructure equipment 102, according to at least some embodiments of the present technology. The communication device 101 is configured to transmit signals to and / or receive signals from a wireless communication network, for example to and from the infrastructure equipment 102. In particular, the communication device 101 may be configured to transmit and / or receive data to and / or through a wireless radio interface provided by the wireless communication network (e.g., a Uu interface between the communication device 101 and a radio access network (RAN), including the infrastructure equipment 102) to and from the wireless radio interface provided by the wireless communication network. The communication device 101 and the infrastructure equipment 102 each include a transceiver (or transceiver circuit) 101.1, 102.1 and a controller (or controller circuit) 101.2, 102.2. Each controller 101.2, 102.2 may be, for example, a microprocessor, a CPU, or a dedicated chipset, etc.

[0047] 5, the transceiver circuitry 101.1 and the controller circuitry 101.2 of the communication device 101 are configured in combination to receive (103) a paging message from a wireless communication network (e.g., from infrastructure equipment 102) while the communication device is operating in an inactive state. The paging message indicates that the wireless communication network (e.g., infrastructure equipment 102) is to transmit a downlink small data transmission, SDT, to the communication device 101, and in response to receiving (103) the paging message, determine (104) whether one or more predefined conditions for receiving the downlink SDT are met, transmit (105) an indication to the wireless communication network (e.g., infrastructure equipment 102) of whether the one or more predefined conditions are met, and receive (106) the downlink SDT from the wireless communication network (e.g., from infrastructure equipment 102) in a manner dependent on whether the one or more predefined conditions are met.

[0048] Basically, the embodiments of the present technology propose that the UE checks certain conditions when responding to a paging triggered MT-SDT in INACTIVE state, such conditions checking, firstly, whether the UE can receive and respond to the MT-SDT, and secondly, how this procedure should be performed. These conditions can be configured explicitly or implicitly. Here, it is assumed that: -UE has suspend indicator RRCRelease In the IEEE 802.11b, the IEEE 802.11b protocol is (or should be) configured with at least one radio bearer for DL ​​SDT (i.e. a radio bearer transporting the downlink SDT), which may have an identifier or ID associated with it. · The UE is configured with a DL RSRP threshold via system information to exclude cell edge UEs in large cells from receiving DL SDT data (such UEs may be able to receive such DL SDT data, but the issue here may be in the transmission of feedback in the uplink by such UEs). The UE is configured with a UL SDT Data Volume Threshold (DVT) via system information to preclude large data transmissions in the uplink (if any) when responding to a paging triggered MT-SDT.

[0049] Figure 6 is a flow diagram illustrating a first example process of communication in a communication system according to an embodiment of the present technology. The process illustrated in Figure 6 is an example of the overall procedure performed by a UE with respect to determining whether certain conditions are satisfied upon receipt of a paging message that triggers downlink MT-SDT, and with respect to the steps to be performed by the UE depending on which conditions are or are not satisfied. At some point before the method illustrated in the example of Figure 6 begins, the network may receive a suspendConfig with a suspendConfig indication. RRCRelease This transitions the UE to RRC_INACTIVE state.

[0050] The method starts at step S1, where the UE receives a Radio Access Network (RAN) paging from the network. At step S2, the UE reads the paging message and determines whether it triggers MT-SDT / DL SDT or whether it is instead related to a legacy or normal paging procedure. In the latter case, the process proceeds to step S3, where the UE may respond appropriately to the legacy / non-MT-SDT paging message and / or paging DCI by performing an action or transmitting a response to the network. However, if the paging message does trigger MT-SDT, the process proceeds to step S4. Now, at steps S4, S6, S7, S8 and S9 of the example process of FIG. 6, the UE may check several conditions based on the content of the paging message.

[0051] The content of the paging message may include one or more of the following: It is expected that a new cause value or a similar indication will be included in the paging message so that the UE knows that the paging message is for DL-SDT. Currently, the paging message includes the UE ID and the access type (which is only applicable for non-3GPP access). In other words, the paging message may include a flag indicating that the wireless communication network transmits a downlink SDT to the communication device. The paging message may carry the Radio Bearer ID of the radio bearer used to carry DL-SDT data to the UE. In other words, the paging message may contain an identifier of the data radio bearer used to transport the downlink SDT from the wireless communication network to the communication device. Those skilled in the art will note that the Radio Bearer ID is unique per UE. The paging message may indicate a logical channel ID and / or an RLC channel ID instead of (or in addition to) the radio bearer ID. In other words, the paging message may contain an identifier of a logical channel used for the transport of data related to the downlink SDT and / or the paging message may contain an identifier of an RLC channel used for the transport of data related to the downlink SDT.

[0052] Alternatively, a universal radio bearer ID or logical channel ID may be reserved for DL-SDT for all UEs.

[0053] The UE may be configured to check one or more of the following conditions according to the example process of FIG. At least one radio bearer / logical channel / RLC channel for DL ​​SDT is configured (e.g., as shown in step S4 of the example of FIG. 6). In other words, the one or more predefined conditions may include at least one data radio bearer configured for the communication device to receive a downlink SDT from the wireless communication network while operating in the inactive state, and / or the one or more predefined conditions may include a logical channel configured for the communication device to receive data associated with the downlink SDT from the wireless communication network while operating in the inactive state, and / or the one or more predefined conditions include a radio link control, RLC, channel configured for the communication device to receive data associated with the downlink SDT from the wireless communication network while operating in the inactive state. The measured downlink RSRP / RSRP of the downlink path loss reference is higher than a configured DL RSRP threshold (e.g., as shown in example step S6 of FIG. 6). In other words, the one or more predetermined conditions may include a measured quality of a reference signal received by the communication device from the wireless communication network being higher than a pre-configured threshold quality required for the communication device to receive a signal from the wireless communication network. Here, the configured DL RSRP threshold may be common (i.e., the same threshold) for both DL and UL SDT. In other words, the pre-configured threshold quality required for the communication device to receive a signal from the wireless communication network may be the same as the pre-configured threshold quality required for the communication device to transmit a signal to the wireless communication network. The UE also checks that the UL SDT data size in its buffer is less than a data volume threshold (DVT) (e.g. as shown in step S7 of the example of FIG. 6). In other words, the one or more predefined conditions may include the amount of data currently stored in the buffer of the communication device being lower than a preconfigured threshold amount. In the absence of a UL SDT, the data size is zero, and this condition is always applicable even if there is no UL data available. However, in many cases, the availability of uplink data may be contingent. For example, by the time the UE receives a DL SDT trigger, there may be UL SDT data that has just arrived in the UE's buffer for transmission. · The UE checks whether there are any uplink SDT resources configured for it (eg as shown in steps S8 and S9 in the example of FIG. 6).

[0054] If in any of steps S4, S6 or S7 the UE determines that the conditions are not satisfied, the process proceeds to step S5, where it declares that the conditions necessary for initiating an MT-SDT procedure are not met and indicates this to the network. In other words, if at least one of the one or more predetermined conditions is not met, the communications device may be configured to transmit a message to the wireless communications network indicating that the one or more conditions are not met and therefore the communications device is not able to receive downlink SDT from the wireless communications network while operating in an inactive state.

[0055] In such a case, the UE may initiate a procedure to transition from RRC_INACTIVE to RRC_CONNECTED, so that it can receive (and acknowledge) downlink SDT data and indeed other data of any size in the CONNECTED mode. In other words, the communication device may be configured to transition from an inactive state to a connected state (e.g., by initiating a legacy RACH procedure), receive downlink data (which may be downlink SDT data or other SDT / non-SDT data) from the wireless communication network while in the connected state, and transmit a feedback signal to the wireless communication network while in the connected state indicating whether the downlink data (which may be downlink SDT data or other SDT / non-SDT data) was successfully received by the communication device. After receiving and acknowledging the downlink data, the UE returns to RRC_INACTIVE or transitions to an RRC_IDLE state. In other words, the communication device may be configured to transition from a connected state to an inactive state after transmitting the feedback signal to the wireless communication network, or to transition from a connected state to an idle state after transmitting the feedback signal to the wireless communication network.

[0056] The UE behavior may also be based on whether it is determined in step S8 (and indeed step S9) whether there is an uplink SDT resource configured for the UE. In other words, the one or more predefined conditions may include a set of grant free resources of the wireless air interface configured for the communication device, under which the communication device can transmit an uplink SDT to the wireless communication network, the grant free resources being valid at the time of receiving a downlink SDT from the wireless communication network. Here, the "valid" grant free resources may include a time alignment timer associated with the grant free resources that have not expired, the time alignment timer indicating a period during which the communication device is synchronized with the wireless communication network in the uplink and / or downlink. That is,

[0057] If the UE determines in step S8 that the CG-SDT resource is configured and valid (i.e., the UL time alignment timer has not expired), then in step S10, the UE's response to the network is to select the CG-SDT for transmission of feedback for the MT-SDT, which may include a CCCH message in the first UL transmission, so that (based on this CCCH message indicating a positive response) the UE can receive the MT-SDT while the MT-SDT is still RRC_INACTIVE. In other words, the communication device may be configured to transmit a feedback signal to the wireless communication network in the grant-free resource if the grant-free resource is configured and valid, the feedback signal indicating that the communication device can receive the downlink SDT from the wireless communication network while operating in the inactive state. Here, the feedback signal is transmitted in a common control channel, a CCCH message, and the transmission of the CCCH message indicates that the communication device can receive the downlink SDT from the wireless communication network while operating in the inactive state.

[0058] If the UE determines in step S8 that the CG-SDT resource is not configured or is not valid, the UE then determines in step S9 whether the RA-SDT resource is configured for the UE. In other words, the one or more predefined conditions may include a set of random access resources of a wireless radio interface configured for the communication device when the communication device may initiate a random access procedure for transmitting an uplink SDT to the wireless communication network.

[0059] If the UE determines in step S9 that the RA-SDT resource is configured, the UE's response to the network (step S11) is to select the RA-SDT for transmission of the feedback of the MT-SDT, which may include a CCCH message for UL transmission (i.e., message 3 or message A), and thus receive the MT-SDT while in RRC_INACTIVE. In other words, the communication device is configured to initiate a random access procedure with the wireless communication network when the grant free resource is not configured and / or is not valid, and when the random access resource is configured, such that the uplink message of the random access procedure transmitted by the communication device to the wireless communication network includes a feedback signal indicating that the communication device can receive the downlink SDT from the wireless communication network while operating in the inactive state. Here, the feedback signal is transmitted within a common control channel, a CCCH message, and the transmission of the CCCH message indicates that the communication device can receive the downlink SDT from the wireless communication network while operating in the inactive state.

[0060] If the UE determines in step S9 that the RA-SDT resources are not configured, the UE's response to the network (step S5) declares that the necessary conditions for initiating the MT-SDT procedure are not met and indicates this to the network. In other words, the communication device may be configured to transmit a message to the wireless communication network indicating that if the grant free resources are not configured and / or are not valid and if the random access resources are not configured, that one or more conditions are not met and therefore that the communication device cannot receive downlink SDT from the wireless communication network while operating in the inactive state. In such a case, the UE may re-initiate the procedure of transitioning from RRC_INACTIVE to RRC_CONNECTED so that it can receive (and confirm) downlink SDT. In other words, the communications device may be configured to initiate a random access procedure with the wireless communications network in response to the received paging message, and the message indicating that one or more conditions are not met and therefore the communications device is unable to receive downlink SDT from the wireless communications network while operating in an inactive state is (for example) a random access procedure uplink message transmitted by the communications device to the wireless communications network including an indication of the cause of initiation of the random access procedure (for example if this cause is mobile terminated data arrival and the network is able to understand the reason for initiation of a RACH procedure or other message indicating that one or more conditions are not met), and in a random access procedure downlink message from the wireless communications network, the communications device receives a configuration of the communications device for receiving downlink data from the wireless communications network.Here, the configuration of the communication device for receiving downlink data from the wireless communication network may include transitioning by the communication device from an inactive state to a connected state, during which the communication device can receive downlink SDT from the wireless communication network. However, the network may instead instruct the UE to remain in the inactive state, and in the case of a RACH procedure, inform the UE of this decision (inactive or connected) in an RRC Resume message. After receiving and acknowledging the downlink SDT, the UE returns to RRC_INACTIVE again or transitions to an RRC_IDLE state. In other words, the communication device is configured to transition from a connected state to an inactive state after transmitting a feedback signal to the wireless communication network, or transition from a connected state to an idle state after transmitting a feedback signal to the wireless communication network.

[0061] In some other configurations of the embodiments of the present technology, if CG-SDT and RA-SDT resources are not configured for the UE, but the UE is in RRC_INACTIVE state and receives a DL-SDT paging message, the UE may perform the RACH procedure using normal RACH resources in this case (i.e., without using the DL-SDT paging message). The UE may then include a new resume cause in the RRC Resume Request message, which notifies the gNB that the UE has responded to the DL-SDT paging message. The gNB may then configure in the RRC Resume message that the UE remains in the INACTIVE state and subsequently receives DL data. In other words, the communication device may be configured to initiate a random access procedure with the wireless communication network in response to the received paging message if the grant free resources are not configured and / or are not valid and if the random access resources are not configured, and an uplink message of the random access procedure transmitted by the communication device to the wireless communication network includes an indication of the cause of the initiation of the random access procedure and receives from the wireless communication network in a downlink message of the random access procedure a configuration of the communication device for the communication device to receive downlink data from the wireless communication network. The advantage of this approach is that DL-SDT and UL-SDT can be configured independently for different UEs, i.e., the DL-SDT procedure works without configuring CG-SDT and special RACH resource partitioning. The UE may use an existing resume cause while responding to the paging message, and the network may extract the UE context based on the RRC Resume Request message received from the UE and decide whether the UE should stay in the inactive mode or move to the connected mode. This decision is informed to the UE in an RRC Resume message.

[0062] After performing any one of steps S3, S5, S10, or SI1, the example process of FIG. 6 ends at step S12.

[0063] 7 is a flow diagram illustrating a second example process for communication in a communication system according to an embodiment of the present technology. The process illustrated in FIG. 7 is a method of operating a communication device configured to transmit signals to and / or receive signals from a wireless communication network (e.g., to or from infrastructure equipment of the wireless communication network).

[0064] The method, which is performed while the communication device is operating in an inactive state, starts at step S21. The method includes receiving a paging message from a wireless communication network in step S22, the paging message indicating that the wireless communication network is to transmit a downlink small data transmission, SDT, to the communication device. In step S23, the process includes determining whether one or more predefined conditions for reception of the downlink SDT are met in response to receiving the paging message. The method then includes transmitting an indication of whether the one or more predefined conditions are met to the wireless communication network in step S24. Following this, in step S25, the process includes receiving the downlink SDT from the wireless communication network in a manner dependent on whether the one or more predefined conditions are met. The process ends in step S26.

[0065] Those skilled in the art will understand that the method shown in Figure 7 may be adapted in accordance with embodiments of the present technology. For example, other intermediate steps may be included in the method, and the steps may be performed in any logical order. Furthermore, although the embodiments of the present technology have been described primarily through the example communication system shown in Figure 5 and through the example flow diagrams of Figures 6 and 7, those skilled in the art will appreciate that what is described herein may be applied to other systems as well.

[0066] Those skilled in the art will further appreciate that the infrastructure equipment and / or communication devices as defined herein may be further defined according to the various configurations and embodiments set out in the previous paragraph. Those skilled in the art will further appreciate that the infrastructure equipment and communication devices as defined and described herein may form part of a communication system other than the communication system defined by the present disclosure, without departing from the scope of the claims.

[0067] The following numbered paragraphs provide further exemplary aspects and features of the present technology. Paragraph 1. 1. A method of operating a communication device configured to transmit signals to and / or receive signals from a wireless communication network over a wireless radio interface provided by the wireless communication network, the method comprising: while the communication device is operating in an inactive state, receiving a paging message from the wireless communication network, the paging message indicating that the wireless communication network is to transmit a downlink small data transmission, SDT, to the communication device; determining whether one or more predetermined conditions for receiving the downlink SDT are met in response to receiving the paging message; transmitting an indication of whether the one or more predetermined conditions are met to the wireless communications network; receiving the downlink SDT from the wireless communications network in a manner dependent on whether the one or more predetermined conditions are met; A method comprising: Paragraph 2. The method of paragraph 1, wherein the one or more predetermined conditions include a set of grant free resources of the wireless radio interface configured for the communication device on which the communication device can transmit an uplink SDT to the wireless communication network and grant free resources that are valid when receiving a downlink SDT from the wireless communication network. Paragraph 3. The method of paragraph 2, wherein the valid grant-free resources include a time alignment timer associated with the non-expired grant-free resources, the time alignment timer indicating a period during which the communications device is synchronized with the wireless communications network in an uplink and / or downlink. Paragraph 4. The method of paragraph 2 or paragraph 3, comprising transmitting a feedback signal to the wireless communications network in the grant free resources if the grant free resources are configured and valid, the feedback signal indicating that the communications device is capable of receiving downlink SDT from the wireless communications network while operating in an inactive state. Paragraph 5. The method of paragraph 4, wherein the feedback signal is transmitted within a common control channel, CCCH message, the transmission of the CCCH message indicating that the communications device is capable of receiving the downlink SDT from the wireless communications network while operating in the inactive state. Paragraph 6. The method of any of paragraphs 2 to 5, wherein the one or more predetermined conditions include a set of random access resources of the wireless radio interface configured for the communication device, at which the communication device may initiate a random access procedure for transmitting an uplink SDT to the wireless communication network. Paragraph 7. The method of paragraph 6, comprising initiating a random access procedure with the wireless communications network if the grant free resource is not configured and / or is not valid and if the random access resource is configured, wherein an uplink message of the random access procedure transmitted by the communications device to the wireless communications network includes a feedback signal indicating that the communications device is able to receive the downlink SDT from the wireless communications network while operating in the inactive state. Paragraph 8. The method of paragraph 7, wherein the feedback signal is transmitted within a Common Control Channel, CCCH message, the transmission of the CCCH message indicating that the communication device is capable of receiving the downlink SDT from the wireless communication network while operating in the inactive state. Paragraph 9. The method of paragraph 7 or 8, comprising the step of transmitting a message to the wireless communications network indicating that if the grant free resource is not configured and / or is not valid and if the random access resource is not configured, the one or more conditions are not met and therefore, while operating in the inactive state, the communications device is not able to receive the downlink SDT from the wireless communications network. Paragraph 10. if the grant free resources are not configured and / or valid and if random access resources are not configured, initiating a random access procedure with the wireless communications network in response to the received paging message, wherein an uplink message of the random access procedure transmitted by the communications device to the wireless communications network includes an indication of a cause for initiation of the random access procedure; 10. The method of any of paragraphs 7 to 9, comprising receiving, in a downlink message of the random access procedure, a configuration of the communications device for receiving downlink data from the wireless communications network. Paragraph 11. 11. The method of any of paragraphs 1 to 10, wherein the one or more predetermined conditions include at least one data radio bearer for which the communications device is configured to receive the downlink SDT from the wireless communications network while operating in the inactive state. Paragraph 12. 12. The method of any of paragraphs 1 to 11, wherein the one or more predetermined conditions include a logical channel configured for the communications device to receive data associated with the downlink SDT from the wireless communications network while operating in the inactive state. Paragraph 13. 13. The method of any of paragraphs 1 to 12, wherein the one or more predetermined conditions include a radio link control, RLC, channel configured for the communications device to receive data associated with the downlink SDT from the wireless communications network while operating in the inactive state. Paragraph 14. 14. The method of any of paragraphs 1 to 13, wherein the one or more predetermined conditions include a measured quality of a reference signal received by the communications device from the wireless communications network that is higher than a preconfigured threshold quality required for the communications device to receive a signal from the wireless communications network. Paragraph 15. 15. The method of paragraph 14, wherein the preconfigured threshold quality required for the communication device to receive a signal from the wireless communication network is the same as the preconfigured threshold quality required for the communication device to transmit a signal to the wireless communication network. Paragraph 16. 16. The method of any of paragraphs 1 to 15, wherein the one or more predetermined conditions include an amount of data currently stored in a buffer of the communications device being lower than a preconfigured threshold amount. Paragraph 17. 17. The method of any of paragraphs 1 to 16, comprising, if at least one of the one or more predetermined conditions is not met, transmitting a message to the wireless communications network indicating that the one or more conditions are not met and therefore, while operating in the inactive state, the communications device is not able to receive the downlink SDT from the wireless communications network. Paragraph 18. initiating a random access procedure with the wireless communications network in response to the received paging message, wherein a message indicating that the one or more conditions are not met and therefore that the communications device is unable to receive the downlink SDT from the wireless communications network while operating in the inactive state is an uplink message of the random access procedure transmitted by the communications device to the wireless communications network, the uplink message including an indication of a cause for initiation of the random access procedure; 18. The method of paragraph 17, comprising receiving, in a downlink message of the random access procedure, a configuration of the communication device for receiving downlink data from the wireless communication network. Paragraph 19. The method of paragraph 18, wherein configuring the communication device to receive downlink data from the wireless communications network includes transitioning, by the communication device, from the inactive state to a connected state, and the communication device is capable of receiving the downlink SDT from the wireless communications network while in the connected state. Paragraph 20. 20. The method of paragraph 19, comprising transitioning from the connected state back to the inactive state after receiving the downlink SDT from the wireless communications network. Paragraph 21. 21. The method of paragraph 19 or paragraph 20, comprising transitioning from the connected state to an idle state after receiving the downlink SDT from the wireless communications network. Paragraph 22. 22. The method of any of paragraphs 1 to 21, wherein the paging message includes a flag indicating that the wireless communications network transmits the downlink SDT to the communications device. Paragraph 23. 23. The method of any of paragraphs 1 to 22, wherein the paging message includes an identifier of a data radio bearer used to transport the downlink SDT from the wireless communications network to the communications device. Paragraph 24. 24. A method according to any of paragraphs 1 to 23, wherein the paging message includes an identifier of a logical channel used to transport data associated with the downlink SDT. Paragraph 25. 25. A method according to any of paragraphs 1 to 24, wherein the paging message includes an identifier of an RLC channel used to transport data associated with the downlink SDT. Paragraph 26. 1. A communications device configured to transmit signals to and / or receive signals from a wireless communications network, comprising: a transceiver circuit configured to transmit and receive signals over a wireless radio interface provided by the wireless communications network; While the communication device is operating in an inactive state, receiving a paging message from the wireless communication network indicating that the wireless communication network will transmit a downlink small data transmission, SDT, to the communication device; determining whether one or more predetermined conditions for receiving the downlink SDT are satisfied in response to receiving the paging message; transmitting an indication of whether the one or more predetermined conditions are met to the wireless communications network; and a controller circuit configured in combination with the transceiver circuit to receive the downlink SDT from the wireless communications network in a manner dependent on whether the one or more predetermined conditions are met. Paragraph 27. 1. A circuit for a communications device configured to transmit signals to and / or receive signals from a wireless communications network, the communications device comprising: a transceiver circuit configured to transmit and receive signals over a wireless radio interface provided by the wireless communications network; While the communication device is operating in an inactive state, receiving a paging message from the wireless communication network indicating that the wireless communication network will transmit a downlink small data transmission, SDT, to the communication device; determining whether one or more predetermined conditions for receiving the downlink SDT are satisfied in response to receiving the paging message; transmitting an indication of whether the one or more predetermined conditions are met to the wireless communications network; and a controller circuit configured in combination with the transceiver circuit to receive the downlink SDT from the wireless communications network in a manner dependent on whether the one or more predetermined conditions are met. Paragraph 28. 1. A method of operating infrastructure equipment forming part of a wireless communications network arranged to transmit signals to and / or receive signals from communications devices over a wireless radio interface provided by the infrastructure equipment, comprising: the infrastructure equipment transmitting a paging message to the communication device, the paging message indicating that a downlink small data transmission, SDT, is to be transmitted; receiving, in response to transmitting the paging message, from the communications device an indication of whether one or more predetermined conditions for reception of the downlink SDT by the communications device are met; and transmitting the downlink SDT to the communications device in a manner dependent on whether the one or more predetermined conditions are met. Paragraph 29. The method of paragraph 28, wherein the one or more predetermined conditions include a set of grant free resources of a wireless radio interface configured for the communication device over which the communication device can transmit an uplink SDT to the infrastructure equipment and grant free resources that are valid when the downlink SDT is transmitted by the infrastructure equipment. Paragraph 30. 30. The method of paragraph 29, wherein the valid grant-free resources include a time alignment timer associated with the unexpired grant-free resources, the time alignment timer indicating a period during which the communications device is synchronized with the infrastructure equipment in the uplink and / or the downlink. Paragraph 31. The method of paragraph 29 or paragraph 30, comprising receiving a feedback signal from the communications device in the grant free resources if the grant free resources are configured and valid, the feedback signal indicating that the communications device is capable of receiving downlink SDT from the infrastructure equipment while operating in the inactive state. Paragraph 32. 32. The method of paragraph 31, wherein the feedback signal is received within a Common Control Channel, CCCH message, receipt of the CCCH message indicating that the communications device is capable of receiving the downlink SDT from the wireless communications network while operating in the inactive state. Paragraph 33. 33. The method of any of paragraphs 29 to 32, wherein the one or more predetermined conditions include a set of random access resources of a wireless radio interface configured for the communication device, within which the communication device can initiate a random access procedure for transmitting an uplink SDT to the infrastructure equipment. Paragraph 34. The method of paragraph 33, comprising receiving, if the grant free resource is not configured and / or is not valid and if the random access resource is configured, a feedback signal from the communications device indicating that the communications device is capable of receiving the downlink SDT from the infrastructure equipment while operating in the inactive state within an uplink message of a random access procedure initiated by the communications device with the infrastructure equipment. Paragraph 35. 35. The method of paragraph 34, wherein the feedback signal is received within a Common Control Channel, CCCH message, receipt of the CCCH message indicating that the communications device is capable of receiving the downlink SDT from the wireless communications network while operating in the inactive state. Paragraph 36. A method as described in any of paragraphs 33 to 35, comprising the step of receiving a message from the communications device indicating that the one or more conditions are not met and therefore that the communications device is unable to receive the downlink SDT from the infrastructure equipment while operating in the inactive state if the grant free resource is not configured and / or is not valid and if the random access resource is not configured. Paragraph 37. if the grant free resources are not configured and / or are not valid and if random access resources are not configured, receiving from the communications device in an uplink message of a random access procedure initiated by the communications device with the infrastructure equipment an indication of the cause of initiation of the random access procedure; 37. A method according to any of paragraphs 33 to 36, comprising a step in which, in a downlink message of the random access procedure, the communications device transmits to the communications device a configuration of the communications device for receiving downlink data from the infrastructure equipment. Paragraph 38. 38. A method according to any of paragraphs 28 to 37, wherein the one or more predetermined conditions include at least one data radio bearer for which the communications device is configured to receive the downlink SDT from the infrastructure equipment while operating in the inactive state. Paragraph 39. 39. The method of any of paragraphs 28 to 38, wherein the one or more predetermined conditions include a logical channel configured for the communications device to receive data associated with the downlink SDT from the infrastructure equipment while operating in the inactive state. Paragraph 40. 40. The method of any of paragraphs 28 to 39, wherein the one or more predetermined conditions include a radio link control, RLC, channel, on which the communications device is configured to receive data associated with the downlink SDT from the infrastructure equipment while operating in the inactive state. Paragraph 41. 41. The method of any of paragraphs 28 to 40, wherein the one or more predetermined conditions include a measured quality of a reference signal received by the communications device from the infrastructure equipment being higher than a preconfigured threshold quality required for the communications device to receive a signal from the infrastructure equipment. Paragraph 42. 42. The method of paragraph 41, wherein the preconfigured threshold quality required for the communications device to receive a signal from the infrastructure equipment is the same as the preconfigured threshold quality required for the communications device to transmit a signal to the infrastructure equipment. Paragraph 43. 43. The method of any of paragraphs 28 to 42, wherein the one or more predetermined conditions include an amount of data currently stored in a buffer of the communications device being lower than a preconfigured threshold amount. Paragraph 44. A method according to any of paragraphs 28 to 43, comprising, if at least one of the one or more predetermined conditions is not met, receiving a message from the communications device indicating that one or more conditions are not met and therefore that the communications device is unable to receive the downlink SDT from the infrastructure equipment while operating in an inactive state. Paragraph 45. receiving a message from the communications device indicating that the one or more conditions are not met and therefore that the communications device is unable to receive the downlink SDT from the infrastructure equipment while operating in the inactive state as an uplink message of a random access procedure initiated by the communications device with the infrastructure equipment, the uplink message of the random access procedure including an indication of the cause of initiation of the random access procedure; 45. The method of paragraph 44, comprising a step in which the communications device transmits to the communications device in a downlink message of the random access procedure a configuration of the communications device for receiving downlink data from the infrastructure equipment. Paragraph 46. Configuring the communications device to receive downlink data from the infrastructure equipment includes transitioning, by the communications device, from the inactive state to a connected state; 46. ​​The method of paragraph 45, wherein the communications device is capable of receiving the downlink SDT from the infrastructure equipment while in the connected state. Paragraph 47. 47. The method of paragraph 46, comprising determining, after receiving the downlink SDT from the infrastructure equipment, that the communications device transitions from the connected state back to the inactive state. Paragraph 48. 48. The method of paragraph 46 or 47, comprising a step of the communications device determining, after receiving the downlink SDT from the infrastructure equipment, to transition from the connected state to an idle state. Paragraph 49. 49. The method of any of paragraphs 28 to 48, wherein the paging message includes a flag indicating that the infrastructure equipment transmits the downlink SDT to the communications device. Paragraph 50. 50. A method according to any of paragraphs 28 to 49, wherein the paging message includes an identifier of a data radio bearer used to transport the downlink SDT from the infrastructure equipment to the communication device. Paragraph 51. A method according to any of paragraphs 28 to 50, wherein the paging message includes an identifier of a logical channel used to transport data associated with the downlink SDT. Paragraph 52. 52. A method according to any of paragraphs 28 to 51, wherein the paging message includes an identifier of an RLC channel used to transport data associated with the downlink SDT. Paragraph 53. 1. Infrastructure equipment forming part of a wireless communications network arranged to transmit signals to and / or receive signals from communications devices, comprising: a transceiver circuit configured to transmit and receive signals over a wireless radio interface provided by the infrastructure equipment; a controller circuit configured in combination with the transceiver circuit while the communications device is operating in an inactive state; transmitting a paging message to the communication device indicating that the infrastructure equipment is to transmit a downlink small data transmission, SDT, to the communication device; receiving, in response to transmitting the paging message, from the communications device an indication of whether one or more predetermined conditions for reception of the downlink SDT by the communications device are satisfied; transmitting the downlink SDT to the communication device in a manner dependent on whether the one or more predetermined conditions are met. Paragraph 54. 1. A circuit for infrastructure equipment forming part of a wireless communications network arranged to transmit signals to and / or receive signals from a communications device, comprising: a transceiver circuit configured to transmit and receive signals over a wireless radio interface provided by the infrastructure equipment; a controller circuit configured in combination with the transceiver circuit while the communications device is operating in an inactive state; transmitting a paging message to the communication device indicating that the infrastructure equipment is to transmit a downlink small data transmission, SDT, to the communication device; receiving, in response to transmitting the paging message, from the communications device an indication of whether one or more predetermined conditions for reception of the downlink SDT by the communications device are satisfied; and transmitting the downlink SDT to the communications device in a manner dependent on whether the one or more predetermined conditions are met. Paragraph 55. A telecommunications system comprising a communications device according to paragraph 26 and infrastructure equipment according to paragraph 53. Paragraph 56. A computer program comprising instructions which, when loaded into a computer, cause the computer to carry out the method according to any of paragraphs 1 to 25 or 28 to 52. Paragraph 57. 57. A non-transitory computer-readable storage medium storing a computer program according to paragraph 56.

[0068] It will be appreciated that for clarity, the above description has described embodiments with reference to different functional units, circuits and / or processors. However, it will be apparent that any suitable distribution of functionality between different functional units, circuits and / or processors may be used without detracting from the embodiments.

[0069] The described embodiments may be implemented in any suitable form including hardware, software, firmware or any combination of these. The described embodiments may optionally be implemented at least in part as computer software running on one or more data processors and / or digital signal processors. The elements and components of any embodiment may be physically, functionally and logically implemented in any suitable way. Indeed functionality may be implemented in a single unit, in multiple units or as part of other functional units. Thus, the disclosed embodiments may be implemented in a single unit or may be physically and functionally distributed between different units, circuits and / or processors.

[0070] Although the present disclosure has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Moreover, while certain features may appear to be described in connection with particular embodiments, those skilled in the art will recognize that the various features of the described embodiments can be combined in any manner suitable for implementing the technology.

Claims

1. 1. A method of operating a communication device configured to transmit signals to and / or receive signals from a wireless communication network over a wireless radio interface provided by the wireless communication network, the method comprising the steps of: while the communication device is operating in an inactive state, receiving a paging message from the wireless communication network, the paging message indicating that the wireless communication network is to transmit a downlink small data transmission, SDT, to the communication device; determining whether one or more predetermined conditions for receiving the downlink SDT are met in response to receiving the paging message; transmitting an indication of whether the one or more predetermined conditions are met to the wireless communications network; receiving the downlink SDT from the wireless communications network in a manner dependent on whether the one or more predetermined conditions are met; A method comprising:

2. 2. The method of claim 1 , wherein the one or more predetermined conditions include a set of grant free resources of the wireless air interface configured for the communication device on which the communication device can transmit uplink SDT to the wireless communication network and grant free resources that are valid when receiving downlink SDT from the wireless communication network.

3. 3. The method of claim 2, wherein the valid grant free resources include a time alignment timer associated with the grant free resources that have not expired, the time alignment timer indicating a period during which the communications device is synchronized with the wireless communications network in an uplink and / or a downlink.

4. 3. The method of claim 2, comprising transmitting a feedback signal to the wireless communication network in the grant free resource if the grant free resource is configured and valid, the feedback signal indicating that the communications device is capable of receiving downlink SDT from the wireless communication network while operating in an inactive state.

5. 5. The method of claim 4, wherein the feedback signal is transmitted within a Common Control Channel, CCCH message, the transmission of the CCCH message indicating that the communications device is capable of receiving the downlink SDT from the wireless communications network while operating in the inactive state.

6. 3. The method of claim 2, wherein the one or more predetermined conditions include a set of random access resources of the wireless radio interface configured for the communication device on which the communication device may initiate a random access procedure for transmitting uplink SDT to the wireless communication network.

7. 7. The method of claim 6, comprising initiating a random access procedure with the wireless communications network if the grant free resources are not configured and / or are not valid and if the random access resources are configured, wherein an uplink message of the random access procedure transmitted by the communications device to the wireless communications network includes a feedback signal indicating that the communications device is able to receive the downlink SDT from the wireless communications network while operating in the inactive state.

8. 8. The method of claim 7, wherein the feedback signal is transmitted within a Common Control Channel, CCCH message, the transmission of the CCCH message indicating that the communications device is capable of receiving the downlink SDT from the wireless communications network while operating in the inactive state.

9. 8. The method of claim 7, comprising: if the grant free resources are not configured and / or valid and if the random access resources are not configured, transmitting a message to the wireless communications network indicating that the one or more conditions are not met and therefore, while operating in the inactive state, the communications device is not able to receive the downlink SDT from the wireless communications network.

10. if the grant free resources are not configured and / or are not valid and if random access resources are not configured, initiating a random access procedure with the wireless communications network in response to the received paging message, wherein an uplink message of the random access procedure transmitted by the communications device to the wireless communications network includes an indication of a cause for initiation of the random access procedure; 8. The method of claim 7, comprising receiving in a downlink message of the random access procedure a configuration of the communication device for the communication device to receive downlink data from the wireless communication network.

11. 2. The method of claim 1, wherein the one or more predetermined conditions include at least one data radio bearer for which the communications device is configured to receive the downlink SDT from the wireless communications network while operating in the inactive state.

12. 2. The method of claim 1, wherein the one or more predetermined conditions include a logical channel over which the communications device is configured to receive data associated with the downlink SDT from the wireless communications network while operating in the inactive state.

13. 2. The method of claim 1, wherein the one or more predetermined conditions include a Radio Link Control, RLC, channel over which the communications device is configured to receive data associated with the downlink SDT from the wireless communications network while operating in the inactive state.

14. 2. The method of claim 1 , wherein the one or more predetermined conditions include a measured quality of a reference signal received by the communications device from the wireless communications network being higher than a preconfigured threshold quality required for the communications device to receive a signal from the wireless communications network.

15. 15. The method of claim 14, wherein a preconfigured threshold quality required for the communication device to receive a signal from the wireless communication network is the same as a preconfigured threshold quality required for the communication device to transmit a signal to the wireless communication network.

16. The method of claim 1 , wherein the one or more predetermined conditions comprises an amount of data currently stored in a buffer of the communication device being lower than a preconfigured threshold amount.

17. 2. The method of claim 1, comprising, if at least one of the one or more predetermined conditions is not met, transmitting a message to the wireless communications network indicating that the one or more conditions are not met and therefore, while operating in the inactive state, the communications device is not able to receive the downlink SDT from the wireless communications network.

18. initiating a random access procedure with the wireless communications network in response to the received paging message, wherein a message indicating that the one or more conditions are not met and therefore that the communications device is unable to receive the downlink SDT from the wireless communications network while operating in the inactive state is an uplink message of the random access procedure transmitted by the communications device to the wireless communications network, the uplink message including an indication of a cause for initiation of the random access procedure; and receiving, in a downlink message of the random access procedure, a configuration of the communications device for receiving downlink data from the wireless communications network.

19. 20. The method of claim 18, wherein configuring the communications device to receive downlink data from the wireless communications network includes transitioning, by the communications device, from the inactive state to a connected state, wherein the communications device is capable of receiving the downlink SDT from the wireless communications network while in the connected state.

20. 20. The method of claim 19, comprising transitioning from the connected state back to the inactive state after receiving the downlink SDT from the wireless communications network.

21. 20. The method of claim 19, comprising transitioning from the connected state to an idle state after receiving the downlink SDT from the wireless communications network.

22. The method of claim 1 , wherein the paging message includes a flag indicating that the wireless communication network transmits the downlink SDT to the communication device.

23. The method of claim 1 , wherein the paging message includes an identifier of a data radio bearer used to transport the downlink SDT from the wireless communication network to the communication device.

24. The method of claim 1 , wherein the paging message includes an identifier of a logical channel used to transport data associated with the downlink SDT.

25. The method of claim 1 , wherein the paging message includes an identifier of an RLC channel used to transport data associated with the downlink SDT.

26. 1. A communications device configured to transmit signals to and / or receive signals from a wireless communications network, comprising: a transceiver circuit configured to transmit and receive signals over a wireless radio interface provided by the wireless communications network; While the communication device is operating in an inactive state, receiving a paging message from the wireless communication network indicating that the wireless communication network will transmit a downlink small data transmission, SDT, to the communication device; determining whether one or more predetermined conditions for reception of the downlink SDT are satisfied in response to receiving the paging message; transmitting an indication of whether the one or more predetermined conditions are met to the wireless communications network; and a controller circuit configured in combination with the transceiver circuit to receive the downlink SDT from the wireless communications network in a manner dependent on whether the one or more predetermined conditions are met.

27. 1. A circuit for a communications device configured to transmit signals to and / or receive signals from a wireless communications network, the communications device comprising: a transceiver circuit configured to transmit and receive signals over a wireless radio interface provided by the wireless communications network; While the communication device is operating in an inactive state, receiving a paging message from the wireless communication network indicating that the wireless communication network will transmit a downlink small data transmission, SDT, to the communication device; determining whether one or more predetermined conditions for reception of the downlink SDT are satisfied in response to receiving the paging message; transmitting an indication of whether the one or more predetermined conditions are met to the wireless communications network; and a controller circuit configured in combination with the transceiver circuit to receive the downlink SDT from the wireless communications network in a manner dependent upon whether the one or more predetermined conditions are met.

28. 1. A method of operating infrastructure equipment forming part of a wireless communications network arranged to transmit signals to and / or receive signals from communications devices over a wireless radio interface provided by the infrastructure equipment, the method comprising the steps of: the infrastructure equipment transmitting a paging message to the communication device indicating that a downlink small data transmission, SDT, is to be transmitted; receiving, in response to transmitting the paging message, from the communication device, an indication of whether one or more predetermined conditions for reception of the downlink SDT by the communication device are met; transmitting the downlink SDT to the communications device in a manner dependent on whether the one or more predetermined conditions are met.

29. 30. The method of claim 28, wherein the one or more predetermined conditions include a set of grant free resources of a wireless radio interface configured for the communication device over which the communication device can transmit an uplink SDT to the infrastructure equipment and grant free resources that are valid when the downlink SDT is transmitted by the infrastructure equipment.

30. 30. The method of claim 29, wherein the valid grant free resources include a time alignment timer associated with the grant free resources that have not expired, the time alignment timer indicating a period during which the communications device is synchronized with the infrastructure equipment in the uplink and / or the downlink.

31. 30. The method of claim 29, comprising receiving a feedback signal from the communication device in the grant free resources if the grant free resources are configured and valid, the feedback signal indicating that the communication device can receive downlink SDT from the infrastructure equipment while operating in the inactive state.

32. 32. The method of claim 31 , wherein the feedback signal is received in a Common Control Channel, CCCH, message, receipt of the CCCH message indicating that the communications device is capable of receiving the downlink SDT from the wireless communications network while operating in the inactive state.

33. 30. The method of claim 29, wherein the one or more predetermined conditions include a set of random access resources of a wireless radio interface configured for the communication device on which the communication device may initiate a random access procedure for transmitting an uplink SDT to the infrastructure equipment.

34. 34. The method of claim 33, comprising receiving, in an uplink message of a random access procedure initiated by the communications device with the infrastructure equipment, a feedback signal from the communications device indicating that the communications device is capable of receiving the downlink SDT from the infrastructure equipment while operating in the inactive state, if the grant free resources are not configured and / or are not valid and if the random access resources are configured.

35. 35. The method of claim 34, wherein the feedback signal is received in a Common Control Channel, CCCH message, receipt of the CCCH message indicating that the communications device is able to receive the downlink SDT from the wireless communications network while operating in the inactive state.

36. 34. The method of claim 33, comprising receiving a message from the communications device indicating that, if the grant free resources are not configured and / or are not valid and if the random access resources are not configured, that the one or more conditions are not met and therefore that the communications device is unable to receive the downlink SDT from the infrastructure equipment while operating in the inactive state.

37. if the grant free resources are not configured and / or are not valid and if random access resources are not configured, receiving from the communications device in an uplink message of a random access procedure initiated by the communications device with the infrastructure equipment an indication of the cause of initiation of the random access procedure; 34. The method of claim 33, comprising: in a downlink message of the random access procedure, the communications device transmitting to the communications device a configuration of the communications device for receiving downlink data from the infrastructure equipment.

38. 30. The method of claim 28, wherein the one or more predetermined conditions include at least one data radio bearer for which the communications device is configured to receive the downlink SDT from the infrastructure equipment while operating in the inactive state.

39. 30. The method of claim 28, wherein the one or more predetermined conditions include a logical channel over which the communications device is configured to receive data associated with the downlink SDT from the infrastructure equipment while operating in the inactive state.

40. 30. The method of claim 28, wherein the one or more predetermined conditions include a Radio Link Control, RLC, channel over which the communications device is configured to receive data associated with the downlink SDT from the infrastructure equipment while operating in the inactive state.

41. 30. The method of claim 28, wherein the one or more predetermined conditions include a measured quality of a reference signal received by the communications device from the infrastructure equipment being higher than a preconfigured threshold quality required for the communications device to receive a signal from the infrastructure equipment.

42. 42. The method of claim 41, wherein a preconfigured threshold quality required for the communications device to receive a signal from the infrastructure equipment is the same as a preconfigured threshold quality required for the communications device to transmit a signal to the infrastructure equipment.

43. 30. The method of claim 28, wherein the one or more predetermined conditions comprises an amount of data currently stored in a buffer of the communications device being lower than a preconfigured threshold amount.

44. 29. The method of claim 28, comprising, if at least one of the one or more predetermined conditions is not met, receiving a message from the communications device indicating that one or more conditions are not met and therefore that the communications device is unable to receive the downlink SDT from the infrastructure equipment while operating in an inactive state.

45. receiving a message from the communications device as an uplink message of a random access procedure initiated by the communications device with the infrastructure equipment, indicating that the one or more conditions are not met and therefore that the communications device is unable to receive the downlink SDT from the infrastructure equipment while operating in the inactive state, the uplink message of the random access procedure including an indication of the cause of initiation of the random access procedure; 45. The method of claim 44, comprising: in a downlink message of the random access procedure, the communications device transmitting to the communications device a configuration of the communications device for receiving downlink data from the infrastructure equipment.

46. Configuring the communications device to receive downlink data from the infrastructure equipment includes transitioning, by the communications device, from the inactive state to a connected state; 46. ​​The method of claim 45, wherein the communications device is capable of receiving the downlink SDT from the infrastructure equipment while in the connected state.

47. 47. The method of claim 46, comprising determining, after receiving the downlink SDT from the infrastructure equipment, that the communications device transitions from the connected state back to the inactive state.

48. 47. The method of claim 46, comprising determining, after receiving the downlink SDT from the infrastructure equipment, that the communications device transitions from the connected state to an idle state.

49. 30. The method of claim 28, wherein the paging message includes a flag indicating that the infrastructure equipment transmits the downlink SDT to the communications device.

50. 30. The method of claim 28, wherein the paging message includes an identifier of a data radio bearer used to transport the downlink SDT from the infrastructure equipment to the communication device.

51. 30. The method of claim 28, wherein the paging message includes an identifier of a logical channel used to transport data associated with the downlink SDT.

52. 30. The method of claim 28, wherein the paging message includes an identifier of an RLC channel used to transport data associated with the downlink SDT.

53. 1. Infrastructure equipment forming part of a wireless communications network arranged to transmit signals to and / or receive signals from communications devices, comprising: a transceiver circuit configured to transmit and receive signals over a wireless radio interface provided by the infrastructure equipment; a controller circuit configured in combination with the transceiver circuit while the communications device is operating in an inactive state; transmitting a paging message to the communication device indicating that the infrastructure equipment will transmit a downlink small data transmission, SDT, to the communication device; receiving, in response to transmitting the paging message, from the communication device, an indication of whether one or more predetermined conditions for reception of the downlink SDT by the communication device are satisfied; transmitting the downlink SDT to the communication device in a manner dependent on whether the one or more predetermined conditions are met.

54. 1. A circuit for infrastructure equipment forming part of a wireless communications network arranged to transmit signals to and / or receive signals from a communications device, comprising: a transceiver circuit configured to transmit and receive signals over a wireless radio interface provided by the infrastructure equipment; a controller circuit configured in combination with the transceiver circuit while the communications device is operating in an inactive state; transmitting a paging message to the communication device indicating that the infrastructure equipment will transmit a downlink small data transmission, SDT, to the communication device; receiving, in response to transmitting the paging message, from the communication device, an indication of whether one or more predetermined conditions for reception of the downlink SDT by the communication device are satisfied; and transmitting the downlink SDT to the communications device in a manner dependent on whether the one or more predetermined conditions are met.

55. A telecommunications system comprising a communication device according to claim 26 and infrastructure equipment according to claim 53.

56. A computer program comprising instructions which, when loaded into a computer, cause said computer to carry out the method of any of claims 1 to 25 or claims 28 to 52.

57. 57. A non-transitory computer readable storage medium storing the computer program of claim 56.

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