Communication system

Abstract

To provide a method, a network node, and user equipment (UE) for improving access by the UE using a Listen-Before-Talk (LBT) procedure.SOLUTION: In a next generation mobile network, UE includes means for receiving configuration information, from an access network node, setting information for setting a duration of a fixed frame period (FFP) that the UE initiates during a period of channel occupancy for an LBT procedure, means for initiating the FFP period according to the duration, and means for adjusting the FFP period such that the duration of the FFP does not overlap with an idle period within the FFP period of the period of channel occupancy initiated by a base station.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to wireless communication systems and devices thereof operating in accordance with 3rd Generation Partnership Project (3GPP) standards or equivalents or derivatives thereof. The present disclosure is particularly, but not exclusively, related to improvements relating to User Equipment (UE) initiated access to unlicensed spectrum using a Listen-Before-Talk (LBT) approach. [Background technology]

[0002] The latest development in the 3GPP standard is the so-called "5G" or "New Radio" (NR) standard, which refers to an evolving communications technology that is expected to support a variety of applications and services, such as Machine Type Communication (MTC), Internet of Things (IoT) / Industrial Internet of Things (IIoT) communications, vehicular communications and automobiles, high-definition video streaming, and / or smart city services. 3GPP intends to support 5G via the so-called 3GPP NextGen Radio Access Network (RAN) and 3GPP NextGen core (NGC) networks. Various details of 5G networks are described, for example, in Non-Patent Document 1.

[0003] End-user communication devices are generally referred to as User Equipment (UE), which may be operated by a human or may include automated (MTC / IoT) devices. For simplicity, this application uses the terms mobile device, user device, or UE to refer to any communication device capable of connecting to a core network via one or more base stations. It will be appreciated that while base stations in 5G / NR communication systems are generally referred to as New Radio Base Stations ("NR-BS") or "gNBs," they may be referred to using the term "eNB" (or 5G / NR eNB), which is more typically associated with Long Term Evolution (LTE) base stations (also commonly referred to as "4G" base stations). Non-Patent Document 2 and Non-Patent Document 3 define, among other things, the following nodes: gNB: A node that provides NR user plane and control plane protocol termination towards the UE and is connected to the 5G core network (5GC) via the NG interface. ng-eNB: A node that provides Evolved Universal Terrestrial Radio Access (E-UTRA) user plane and control plane protocol termination towards the UE and is connected to the 5GC via the NG interface. En-gNB: A node that provides NR user plane and control plane protocol termination towards the UE and acts as a secondary node in E-UTRA-NR Dual Connectivity (EN-DC). NG-RAN node: either gNB or ng-eNB

[0004] 3GPP has also defined the so-called "Xn" interface as the network interface between neighboring NG-RAN nodes.

[0005] The Physical Uplink Control Channel (PUCCH) carries a set of information called Uplink Control Information (UCI). The format of the PUCCH depends on what kind of information the UCI carries. The PUCCH format to be used is determined by how many bits of information are to be carried and how many symbols are allocated. The UCI used in NR (5G) includes one or more of the following information: Channel State Information (CSI), ACK / NAK, and Scheduling Request (SR). This is entirely the same in LTE (4G).

[0006] Next-generation mobile networks support diverse service requirements, which have been classified by the International Telecommunication Union (ITU) into three categories: Enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low-Latency Communications (URLLC), and Massive Machine Type Communications (mMTC). eMBB aims to provide enhanced support for traditional mobile broadband, focusing on services that require large and guaranteed bandwidth, such as High Definition (HD) video, Virtual Reality (VR), and Augmented Reality (AR). URLLC is a requirement for critical applications such as autonomous driving and factory automation, which require guaranteed access within a very short time. MMTC needs to support a large number of connected devices, such as smart metering and environmental monitoring, but can usually tolerate some access delay. Some of those applications may have relatively loose Quality of Service / Quality of Experience (QoS / QoE) requirements, whereas some applications may have relatively stringent QoS / QoE requirements (e.g., high bandwidth and / or low latency).

[0007] 5G may be implemented using spectrum allocated to 4G communications (e.g., Long Term Evolution (LTE) or LTE-Advanced) or unlicensed / unallocated spectrum (e.g., unlicensed bands at 5 and 6 GHz, also known as mmWave, unlicensed bands up to 60 GHz). This scenario is referred to as spectrum sharing, which allows network operators to roll out 5G access technologies relatively quickly and cost-effectively. 5G's use of unlicensed spectrum, whether in a standalone context or in combination with unlicensed or shared spectrum, is referred to as NR-U.

[0008] To ensure that the disturbance / interference caused by 5G communications to other communications in 4G or unlicensed spectrum is kept to a minimum, 5G employs the so-called Listen-Before-Talk (LBT) approach. LBT is a mechanism whereby a communication device applies Clear Channel Assessment (CCA) before using a shared / unlicensed spectrum (or channel). When LBT is applied, a transmitter listens / senses the channel to determine whether the channel is free or busy, and performs transmission only if the channel is sensed as free. Effectively, a transmitter needs to determine whether a channel in the shared / unlicensed spectrum is used by another transmitter (e.g., UE or base station) before it is allowed to transmit ("talk") using that channel. In particular, CCA employs Energy Detection (ED) to determine whether the channel is clear or not.

[0009] NR radio access operating with shared spectrum channel access can operate using several different modes, where a primary cell (PCell), secondary cell (SCell), and / or primary SCell (PSCell) can operate using a shared spectrum and a SCell can be configured for downlink only. A gNB operates in either a dynamic channel access mode or a quasi-static channel access mode. In both channel access modes, a gNB and / or UE can apply LBT before performing a transmission on a cell configured with shared spectrum channel access.

[0010] In addition to dynamic scheduling of resources, there are two schemes for quasi-static scheduling of resources for uplink transmissions (referred to as "configured grant (CG)"). In the first type of quasi-static scheduling (referred to as configured grant type 1), all transmission parameters (including periodicity, time offset, and frequency resources) as well as modulation and coding schemes are configured by the base station using Radio Resource Control (RRC) signaling. In the type 1 configuration, the UE can start using the configured grant at a time set by the periodicity and offset. The offset parameter is used to effectively control the time when the UE activates the configured grant. In the second type of quasi-static scheduling (configured grant type 2), the periodicity is configured by the base station using Radio Resource Control (RRC) signaling, while the resources are provided when the grant is to be activated by the physical downlink control channel (PDCCH). In this case, no time offset is used since the activation time is well defined by the timing of the PDCCH.

[0011] The UE and gNB may be implemented as Frame Based Equipment (FBE), where the transmission / reception structure utilizes a frame-based approach to LBT access, which utilizes periodic timing with a period equal to the so-called Fixed Frame Period (FFP). Alternatively, the UE and gNB may be implemented as Load Based Equipment (LBE), where the transmission / reception structure utilizes a load-based approach to LBT access, where access is not fixed in time during the FFP, but is demand-driven (similar to Wi-Fi systems).

[0012] In the frame-based approach, the initiating FBE (which can be a gNB or a UE) performs CCA for a single observation slot (typically, for example, 9us) just before entering the start of a new FFP. An operating channel is considered occupied if the energy level in at least one operating channel exceeds the associated ED Threshold Level (TL). If the initiating device finds one or more operating channels to be clear, it can immediately start transmitting during the FFP. If the initiating device finds an operating channel to be occupied, it does not transmit on that channel during the subsequent FFP (although it may be allowed to continue short control signaling transmissions on this channel, provided that certain requirements are met). For devices with simultaneous transmissions on multiple (adjacent or non-adjacent) operating channels, the device is allowed to continue transmitting on the other operating channels, provided that the CCA check did not detect any signals on those channels.

[0013] The total time that an initiating FBE may transmit on a given channel following a successful CCA without re-evaluating the availability of that channel is defined as the Channel Occupancy Time (COT). During this COT, the initiating device may transmit and / or receive on the corresponding operating channel(s). The COT is followed by an idle period during which the initiating device does not transmit any communication to the responding device(s) until the start of the next FFP. In some cases, the responding device(s) also does not transmit to the initiating device during the idle period of the FFP to the initiating device. The maximum COT associated with a successful CCA for an FBE operation is generally no more than 95% of the FFP, and the idle period is generally at least 5% of the channel occupancy time, or 100 microseconds (if greater).

[0014] An initiating equipment may perform multiple transmissions during a given COT without performing additional CCA on the corresponding operating channel or channels, as long as the gap between such transmissions does not exceed a maximum transmission gap (typically, e.g., 16 us). If the gap exceeds the maximum transmission gap, the initiating equipment may continue transmitting, provided that the additional CCA indicates that no transmissions have an energy detection level above the associated ED TL. Any additional CCA is performed within the gap immediately preceding a transmission and within a single observation slot. Any transmission gap is treated as being part of the COT.

[0015] The initiator device may also receive transmissions during the COT from one or more associated responder devices (the responder devices may be UEs or gNBs) by granting permission to one or more responder devices to transmit on corresponding operating channels during the COT.

[0016] Any one or more responding devices that receive such a transmission grant from the associated initiating device may continue transmission on the current operating channel without performing CCA, as long as the transmission begins within the maximum transmission gap (typically, e.g., 16 us) following the last transmission by the initiating device that issued the grant. Any responding device that does not continue such transmission within the maximum transmission gap transmission following the last transmission from the initiating device that issued the grant performs CCA on the associated one or more operating channels during an observation slot during a period (typically, e.g., 25 us) that ends just before the allowed transmission time. If energy above the associated ED TL is detected, the transmission grant for the responding device is treated as withdrawn. If any detected energy falls below the associated ED TL, the responding device may perform transmission on the current operating channel for the remaining COT of the current FFP. The responding device may perform such transmission on this operating channel, provided that the gap between multiple transmissions does not exceed the maximum transmission gap. When the transmission by the responding device is completed, the transmission grant for the responding device is treated as withdrawn.

[0017] If the initiating device correctly receives a packet intended for that device, it skips the CCA and immediately proceeds with transmitting management and control frames (e.g., acknowledgement (ACK) and / or Block ACK frames). A successive series of such transmissions by the initiating device without performing a new CCA should still not exceed the maximum COT. For multicast purposes, each ACK transmission associated with the same data packet may be made by multiple individual devices in sequence.

[0018] If the initiating device is a gNB, the initiating gNB therefore occupies the channel at the beginning of a fixed frame period after the one-shot LBT. During each COT, multiple transmissions are allowed in different directions and are subject to the one-shot LBT. A UE served by a gNB can transmit during the COT, where the gNB is the initiating device and the served UE is the responding device in FBE. For the latest standard release, it has also been agreed that for semi-static channel access, the UE may be the COT initiator.

[0019] During a gNB's FFP, any UE served by the gNB should not transmit during idle periods of that gNB, whether it is operating as a COT responder or a COT initiator. Nevertheless, when the gNB operates as a COT initiator, it is permitted to transmit during idle periods of the UE's FFP. However, when the gNB operates as a COT responder, it is not permitted to transmit during idle periods of the UE that initiated the COT. Moreover, when the gNB operates as a COT responder, it is still not permitted to transmit during idle periods of its own FFP.

[0020] For UEs (especially URLLC / IIoT UEs) operating using shared / unlicensed spectrum, enhanced channel access mechanisms to support UE initiated COT are under development. These include support for semi-static channel access mode using any scheduled / configured UL channel / signal transmission to initiate COT by the UE in RRC connected ("RRC_CONNECTED") mode, with the possibility of later extension for the case when the UE is in IDLE / INACTIVE mode.

[0021] The channel access mechanism supports UE-gNB COT sharing in semi-static channel access mode. Moreover, for the semi-static channel access mode, the start of FFP during the UE-initiated COT may be different from the start of FFP during the gNB-initiated COT. Also, it is possible that the FFP period during the UE-initiated COT may be different from the FFP period during the gNB-initiated COT.

[0022] Each FFP is defined by respective FFP configuration parameters, which include an FFP offset parameter that defines when the corresponding FFP starts relative to a radio frame, and an FFP periodicity parameter that defines the period and / or duration of the corresponding FFP.

[0023] The possibility that different UEs may have different FFP offsets relative to the start of the radio frame during the UE initiated COT may result in collisions between different UEs, potentially causing a high priority transmission from one UE to be blocked by a low priority transmission from another UE.

[0024] For example, a first UE initiator with a first FFP offset may sense a clear channel and begin transmitting a configured grant uplink transmission during the FFP before a second UE with a second, longer, FFP offset has a chance to start transmitting. Thus, even if the second UE has data to transmit in the uplink using the configured grant in the uplink that is higher priority data than the first UE's priority, the transmission may be effectively blocked by the first UE's lower priority transmission when performing CCA because the second UE does not sense the first UE's transmission and start transmitting. This problem may result in long-term blocking of the second UE transmission because the UE may repeatedly start a COT for each FFP.

[0025] These issues are particularly relevant for URLLC devices, where low latency and high reliability are particularly important. Such URLLC devices typically use configured grants for communication in the uplink with CG periods and / or offsets that represent when the UE is allowed to transmit, and may have configured retransmission timers (e.g., cg-RetransmissionTimer) that dictate when the UE should attempt to retransmit data in the event that an acknowledgment is not received.

[0026] For example, the fact that a gNB may not know in advance that a given UE may need to transmit URLLC data, and that another (URLLC or non-URLLC) UE may detect during an idle period and initiate its own COT, can potentially lead to undesirable delays and associated latency in the transmission of the URLLC data.

[0027] To help harmonize UL CG enhancements for NR-U and URLLC, at least for FBE, it is currently believed that configuration of the CG retransmission timer should not be made mandatory when configured grant type 1 or type 2 is configured on unlicensed spectrum. This would potentially result in additional complexity for URLLC devices. Therefore, further development is likely to be required to help harmonize CG features for URLLC and NR-U.

[0028] Thus, there is a need for improvements in how LBT mechanisms are implemented, particularly in the context of UE-initiated COT. While those improvements are particularly needed to support semi-statically configured URLLC devices, it will be appreciated that the improvements may have broader benefits beyond URLLC devices and require improvements in the way in which either URLLC or non-URLLC devices operate. [Prior art documents] [Non-patent literature]

[0029] [Non-Patent Document 1] 'NGMN 5G White Paper' V1.0[online], Next Generation Mobile Networks (NGMN) Alliance, Internet<URL: https: / / www.ngmn.org / 5g-white-paper.html> [Non-Patent Document 2] 3GPP Technical Specification (TS) 38.300 V16.3.0 [Non-Patent Document 3] 3GPP Technical Specification (TS) 37.340 V16.3.0 Summary of the Invention

[0030] SUMMARY OF THE PRESENT EMBODIMENT The present invention therefore seeks to provide an improved method, and associated apparatus, that at least partially addresses the above needs.

[0031] For efficient understanding by those skilled in the art, the present invention will be described in detail in the context of a 3GPP system (5G network), but the principles of the present invention may be applied to other systems as well.

[0032] Exemplary aspects of the invention are set out in the accompanying independent claims. Optional but advantageous features are set out in the accompanying dependent claims.

[0033] In one exemplary aspect, a method is provided that is performed by a user equipment (UE) in communication with a radio access network (RAN), the method including: maintaining information for configuring timing of a fixed frame period (FFP) for a listen-before-talk (LBT) procedure; performing a clear channel assessment, CCA, when the UE has data to be transmitted to determine whether a communication channel is clear; initiating a channel occupation time, COT, for the UE during a subsequent FFP when the CCA indicates that the communication channel is clear; starting transmission of the data to be transmitted during the COT; receiving an indication from a node of the RAN that transmission should be stopped; and suspending transmission of the data in response to the received indication.

[0034] In one exemplary aspect, a method is provided that is performed by a user equipment (UE) in communication with a radio access network (RAN), the method including: maintaining information for configuring a fixed frame period (FFP) timing and a plurality of energy detection (ED) thresholds for a listen-before-talk (LBT) procedure, where each ED threshold of the plurality of thresholds is associated with a different respective possible data characteristic that data transmitted by the UE may have; performing a clear channel assessment, CCA, when the UE has data to be transmitted to determine whether the communication channel is clear, where the CCA includes comparing a detected energy level with an ED threshold of the plurality of ED thresholds associated with a corresponding characteristic of the data to be transmitted; and starting a channel occupation time, COT, for the UE during a subsequent FFP when the CCA indicates that the communication channel is clear; and starting transmission of the data to be transmitted during the COT.

[0035] In one exemplary aspect, a method is provided that is performed by a radio access network (RAN) serving a plurality of user equipments (UEs), each UE being each configured with a fixed frame period (FFP) for a listen-before-talk (LBT) procedure, the method including: receiving data transmitted by the first UE during a first channel occupation time, COT, whereby a first UE of the plurality of UEs is configured, and receiving a transmission by a second UE during a second COT, whereby a second UE of the plurality of UEs is configured, the transmission by the second UE being received during the first COT initiated by the first UE; determining whether transmission by the first UE should be stopped based on the transmission by the second UE; and when it is determined that transmission by the first UE should be stopped, sending to the first UE an indication that transmission by the first UE should be stopped.

[0036] In one exemplary aspect, a method is provided that is performed by a radio access network (RAN) serving at least one user equipment (UE), each UE being configured with a fixed frame period (FFP) for a listen-before-talk (LBT) procedure, the method including providing configuration information to each UE for the listen-before-talk (LBT) procedure, each capable of initiating a channel occupation time (COT) of the fixed frame period (FFP) for that UE that is subject to clear channel assessment (CCA), for at least partially configuring a timing of a respective FFP, the configuration information provided by the radio access network (RAN) being configured to configure a respective timing between the FFPs of each UE that is based on a corresponding FFP of a node of the RAN.

[0037] The configuration information provided by a radio access network (RAN) may be configured, based on the RAN node's corresponding FFPs, to ensure at least one of the following: respective timings during each UE's FFP, such that none of the FFPs for the UE are longer than a period corresponding to an idle period during that UE's FFP and do not overlap with the end of the RAN node's corresponding FFP; respective timings during each UE's FFP, such that all of the FFPs for the UE occur during the RAN node's corresponding FFP, such that none of the FFPs for the UE are longer than a period corresponding to an idle period during the UE's FFP and do not extend beyond the end of the RAN node's corresponding FFP; respective timings during each UE's FFP, such that at least a COT portion of the FFP for each UE does not coincide with at least a COT portion of an FFP for another UE served by the RAN node; a respective duration during at least one of each UE's FFPs equal to the duration of the RAN node's corresponding FFP divided by an integer divisor; or respective periodicity during each UE's FFP equal to the periodicity of the RAN node's corresponding FFP divided by an integer divisor.

[0038] In one exemplary aspect, a method is provided that is performed by a user equipment (UE) in communication with a radio access network (RAN), the method including receiving configuration information from a node of the RAN for at least partially configuring timing of fixed frame period (FFP) for a listen-before-talk (LBT) procedure for the UE, the UE being capable of starting a respective channel occupation time (COT) during each FFP that is subject to clear channel assessment (CCA), and determining timing of the FFP for the UE based on the received configuration information, the UE determining timing between the UE's FFPs that are based on corresponding FFPs of the RAN node based on the received configuration information.

[0039] The UE may determine the timing between the UE's FFPs based on the received configuration information, in which at least one of the following applies: none of the FFPs for the UE are longer than a period corresponding to an idle period between the UE's FFPs and do not overlap with the end of the corresponding FFP of the RAN node; all of the FFPs for the UE are longer than a period corresponding to an idle period between the UE's FFPs and occur during the corresponding FFP of the RAN node without extending beyond the end of the corresponding FFP of the RAN node; at least a COT portion of the FFP for the UE does not coincide with at least a COT portion of the FFP for another UE served by the RAN node; the respective duration between at least one of the UE's FFPs is equal to the duration of the corresponding FFP of the RAN node divided by an integer divisor; or the respective period between the UE's FFPs is equal to the period of the corresponding FFP of the RAN node divided by an integer divisor.

[0040] In one exemplary aspect, a user equipment (UE) in communication with a radio access network (RAN) is provided, the UE including a controller and a transceiver, the controller is configured to maintain information for configuring timing of a fixed frame period (FFP) for a listen-before-talk (LBT) procedure, perform a clear channel assessment, CCA, when the UE has data to be transmitted to determine whether a communication channel is clear, initiate a channel occupation time, COT, for the UE during a subsequent FFP when the CCA indicates that the communication channel is clear, control the transceiver to start transmitting the data to be transmitted during the COT, control the transceiver to receive an indication from a node of the RAN that transmission should be stopped, and control the transceiver to suspend transmission of the data in response to the received indication.

[0041] In one exemplary aspect, a user equipment (UE) in communication with a radio access network (RAN) is provided, the UE including a controller and a transceiver, the controller is configured to maintain information for configuring a fixed frame period (FFP) timing and a plurality of energy detection (ED) thresholds for a listen-before-talk (LBT) procedure, each ED threshold of the plurality of thresholds being associated with a different respective possible data characteristic that data transmitted by the UE may have, and to perform a clear channel assessment, CCA, when the UE has data to be transmitted to determine whether the communication channel is clear, the CCA including comparing a detected energy level with an ED threshold of the plurality of ED thresholds associated with a corresponding characteristic of the data to be transmitted, and when the CCA indicates that the communication channel is clear, to start a channel occupation time, COT, for the UE during a subsequent FFP and to control the transceiver to start transmitting the data to be transmitted during the COT.

[0042] In one exemplary aspect, a radio access network (RAN) node serving a plurality of user equipments (UEs), each UE being each configured with a fixed frame period (FFP) for a listen-before-talk (LBT) procedure, the RAN node including a controller and a transceiver, the controller configured to: control the transceiver to receive data transmitted by the first UE during a first channel occupation time, COT, initiated by the first UE during an FFP whereby a first UE of the plurality of UEs is configured; control the transceiver to receive a transmission by a second UE during a second COT initiated by the second UE during an FFP whereby a second UE of the plurality of UEs is configured, the transmission by the second UE being received during the first COT initiated by the first UE; determine based on the transmission by the second UE whether transmission by the first UE should be stopped; and when it is determined that transmission by the first UE should be stopped, control the transceiver to transmit to the first UE an indication that transmission by the first UE should be stopped.

[0043] In one exemplary aspect, a radio access network (RAN) node serving a plurality of user equipments (UEs), each configured with a fixed frame period (FFP) for a listen-before-talk (LBT) procedure, the RAN node including a controller and a transceiver, the controller configured to provide configuration information to each UE for the listen-before-talk (LBT) procedure, each capable of initiating a channel occupation time (COT) of the fixed frame period (FFP) for that UE subject to clear channel assessment (CCA), the configuration information provided by the radio access network (RAN) configured to configure respective timings between the FFPs of each UE based on a corresponding FFP of the RAN node.

[0044] In one exemplary aspect, a user equipment (UE) in communication with a radio access network (RAN) is provided, the UE including a controller and a transceiver, the controller controls the transceiver to receive configuration information from a node of the RAN for at least partially configuring timing of fixed frame period (FFP) for a listen-before-talk (LBT) procedure for the UE, the UE is capable of starting a respective channel occupation time (COT) during each FFP subject to clear channel assessment (CCA), and is configured to determine timing of the FFP for the UE based on the received configuration information, and the controller is configured to determine timing between the FFPs of the UE that is based on corresponding FFPs of the node of the RAN based on the received configuration information.

[0045] Exemplary aspects of the invention extend to corresponding systems, apparatus, and computer program products, such as computer-readable storage media having instructions stored thereon, the instructions being operable to program a programmable processor to perform the methods described in the above-identified exemplary aspects and implementations or recited in the claims, and / or to program a computer suitably adapted to provide an apparatus as recited in any of the claims.

[0046] Each feature disclosed in this specification (including the claim language) and / or illustrated in the drawings may be incorporated into the invention independently of (or in any combination with) any other disclosed and / or illustrated feature. Without specific limitation, any feature of a claim dependent on a particular independent claim may be incorporated into that independent claim in any combination or individually.

[0047] Exemplary embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0048] [Figure 1] 1 illustrates generally a mobile (cellular or wireless) telecommunications system in which exemplary embodiments of the present invention may be applied; [Diagram 2] 2 illustrates generally some improved LBT-related features that can be implemented in the system of FIG. 1. [Diagram 3] 2 illustrates generally some other improved LBT-related features that can be implemented in the system of FIG. 1. [Figure 4] 2A-2C are schematic illustrations of some variations of improved LBT-related features that can be implemented in the system of FIG. 1; [Diagram 5] 2 is a schematic block diagram of a mobile device forming part of the system shown in FIG. 1; [Figure 6]2 is a schematic block diagram of an access network node (eg a base station) forming part of the system shown in FIG. 1; [Figure 7] FIG. 2 is a simplified timing diagram illustrating a UE COT release procedure for the system shown in FIG. 1. [Figure 8] 2 is a simplified timing diagram illustrating a UE FFP configuration procedure for the system shown in FIG. 1.

[0049] overview An exemplary telecommunications system is now described, by way of example only, with reference to Figures 1-4.

[0050] FIG. 1 illustrates generally a mobile ("cellular" or "wireless") telecommunications system 1 in which exemplary embodiments of the present invention are applicable.

[0051] In network 1, user equipment (UE) 3-1, 3-2, 3-3 (e.g., cellular telephones and / or other mobile devices) may communicate with each other via base stations 5, which in turn may communicate with each other via Radio Access Network (RAN) nodes 5 operating according to one or more compatible Radio Access Technologies (RATs). In the illustrated example, the RAN nodes 5 include NR / 5G base stations or "gNBs" 5 that operate one or more associated cells 9. Communications via the base stations 5 are typically routed through a core network 7 (e.g., a 5G core network or an evolved packet core network (EPC)).

[0052] As one skilled in the art will appreciate, although three UEs 3 and one base station 5 are shown in FIG. 1 for illustrative purposes, the system will typically include other base stations and UEs when implemented.

[0053] Each base station 5 controls one or more cells associated therewith, either directly or indirectly via one or more other nodes (such as home base stations, repeaters, remote radio heads, and / or distributed units). It will be appreciated that the base stations 5 may be configured to support both 4G and 5G, and / or any other 3GPP or non-3GPP communication protocols.

[0054] The UEs 3 and their serving base stations 5 are coupled via a suitable air interface (e.g. the so-called "Uu" interface and / or similar). Neighbouring base stations 5 may be connected to each other via a suitable inter-base station interface (such as the so-called "X2" interface and / or "Xn" interface).

[0055] The core network 7 includes a number of logical nodes (or "functions") for supporting communications in the telecommunications system 1. In this example, the core network 7 includes a Control Plane Function (CPF) 10 and one or more User Plane Functions (UPF) 11. The CPF 10 includes one or more Access and Mobility Management Functions (AMF) 10-1, one or more Session Management Functions (SMF), and several other functions 10-n.

[0056] The base stations 5 are connected to the core network nodes via appropriate interfaces (or "reference points"), for example the N2 reference point between the base stations 5 and the AMF 10-1 for communication of control signaling, and the N3 reference point between the base stations 5 and the respective UPFs for communication of user data. The UEs 3 are each connected to the AMF 10-1 via a logical Non-Access Stratum (NAS) connection through an N1 reference point (similar to the S1 reference point in LTE).

[0057] The one or more UPFs 11 are connected to an external data network (eg, an IP network such as the Internet) via a reference point N6 for communication of user data.

[0058] The AMF 10-1 performs mobility management related functions, maintains a non-NAS signaling connection with each UE 3, and maintains UE registrations. The AMF 10-1 is also responsible for managing paging. The SMF 10-2 provides session management functionality (which in LTE formed part of the MME functionality) and in addition combines some control plane functions (provided by the Serving Gateway and Packet Data Network Gateway in LTE). The SMF 10-2 also allocates an IP address to each UE 3.

[0059] In this example, at least some of the UEs 3-1 are configured as URLLC UEs, however, it will be appreciated that each UE 3 may support one or more services that may fall into any of the above defined categories (URLLC / eMBB / mMTC), each of which typically has associated requirements (e.g., delay / data rate / packet loss requirements, etc.) that may differ for different services.

[0060] Each UE 3 operates as a Frame Based Equipment (FBE) and is each configured to implement a Listen-before-talk (LBT) procedure, in which each UE 3 is configured with a respective Fixed Frame Period (FFP) and can operate as a Channel Occupancy Time (COT) initiator or a COT responder. When operating as a COT initiator, the UE performs normal procedures for accessing the associated unlicensed or shared spectrum, including a Clear Channel Assessment (CCA) based on a comparison of a detected energy level with an Energy Detection (ED) threshold level (TL) during a single observation slot and immediately prior to entering the start of a new FFP. When a COT initiating UE finds that one or more operating channels are clear, it can immediately begin transmitting during the FFP. When the initiating UE finds that the operating channel should be occupied, it does not transmit on that channel during the subsequent FFP (although it may be allowed to continue short control signaling transmissions on this channel, provided that certain requirements are met).

[0061] Similarly, gNB5 is configured to operate as an FBE and implement an LBT procedure in which gNB5 is configured with a gNB FFP and can operate as a COT initiator or as a COT responder. When operating as a COT initiator, gNB5 performs normal procedures for accessing unlicensed or shared spectrum, including a CCA based on a comparison of detected energy levels with the ED TL, during a single observation slot and immediately prior to entering the start of a new FFP.

[0062] Each FFP is defined by respective FFP configuration parameters, including an FFP offset parameter that defines when the corresponding FFP starts, and an FFP period that defines the period and / or duration of the corresponding FFP. It will be appreciated that the respective proportions of the FFPs that may form the COT (when started) and associated idle time may be defined by other parameters that may be pre-configured in the UE 3 or gNB 5, or may be dynamically or semi-statically configured by the gNB 5.

[0063] In this example, each UE FFP may be configured with an FFP offset that is different from the FFP offset of the FFP for gNB5. Similarly, in this example, each UE FFP may be configured with an FFP periodicity that is different from the FFP periodicity of the FFP for gNB5.

[0064] It will be appreciated that the FFP offset parameters for configuring the start of each UE's respective FFP during the UE-initiated COT for a radio frame are provided to the UE 3 by dedicated RRC signaling from the gNB 5, but may alternatively or additionally be provided using a System Information Block (SIB), e.g., by a Type 1 SIB (SIB1). The UE FFP period may also be explicitly configured using RRC signaling and / or a SIB (e.g., SIB1), or may be implicitly determined at the UE 3 based on other higher layer parameters. For example, it will be appreciated that the UE FFP period and / or duration may be implicitly determined based on other configurations, such as Random Access Channel (RACH) configuration parameters or uplink configured grant (CG) configuration parameters.

[0065] With particular reference to Figures 2 and 3, the gNB 5 and UE 3 are advantageously configured with several optional features to mitigate or avoid collisions between different UEs using the shared / unlicensed spectrum, prohibit one UE from interfering with another, and / or make handling of collisions simpler.

[0066] FIG. 2 illustrates generally some improved LBT-related features that can be implemented in the system of FIG.

[0067] As can be seen in FIG. 2, the gNB 5 in this example is configured to be able to cancel an uplink transmission of a transmitting UE 3-1 when another UE 3-2 has uplink data to transmit with higher priority (e.g., a higher priority URLLC transmission). In this example, this is achieved by sending an indication to the transmitting UE that the transmission should be stopped (e.g., in the form of a COT "cancel" or "release" indicator) using appropriate signaling during the downlink period of the transmitting UE's FFP. The release indication is provided in this example in the form of a Downlink Control Information (DCI) field or similar, which is an appropriate form of a Physical Downlink Control Channel (PDCCH). The release indicator triggers the UE 3-1 to release the COT initiated by the corresponding UE, and doing so supports the higher priority transmission from the other UE 3-2.

[0068] In this example, when a transmission or service of UE3-1 is cancelled and the corresponding COT is released by the downlink release indicator, the UE3-1 for which the transmission was cancelled will not attempt to start another COT for the same transmission or service until the gNB5 reschedules UL transmission for that UE3-1.

[0069] The COT release indicator may be provided in any suitable manner. The COT release indicator may be in the form of, for example, a single bit of a DCI set to "1" (or "0") to indicate that the UE should release an ongoing UE initiated COT or a shared COT that the UE shares with the gNB5. The single bit indicator may include a newly added bit of the DCI format or may reuse an existing bit of the DCI format. The COT release indicator may instead include a DCI field containing a CG configuration index of the configured grant for the UE transmission to be canceled. The COT release indicator may include, for example, a DCI field containing a bitmap indicator for deactivating one or more indicated configured grants with each bit corresponding to the respective configured grant, the bit being set to "1" to indicate that the corresponding grant should be canceled and to "0" (or vice versa) to indicate that the corresponding grant is not canceled. It will be appreciated that the options do not have to be mutually exclusive, and that the gNB may be capable of using (and the UE may be capable of interpreting) different DCI configurations in different circumstances.

[0070] Advantageously, each UE 3 is configured with different ED threshold levels for different transmission priorities. Thus, a UE 3 (UE2 3-2 in FIG. 2) with data to transmit with high priority (e.g., URLLC) can perform CCA in its observation slot to determine whether the corresponding uplink channel is occupied using a higher ED threshold than if it only had data to transmit with low priority. Thus, a UE 3-2 with data to transmit with high priority can start COT at the start of its next FFP and begin transmitting high priority data even if the channel is considered to be otherwise occupied based on a lower ED threshold level for data transmitted by another UE 3 (e.g., UE1 3-1 in FIG. 2) with lower priority (e.g., URLLC). Thus, a UE 3-2 with a higher priority transmission is not prevented from simply starting its COT by the channel being occupied by a lower priority transmission from another UE 3-1.

[0071] The gNB5 is configured to detect high priority UL transmissions from the corresponding UE 3-2 based on the FFP for that UE. Since the gNB5 configures the UE's transmission opportunities via the UL configured grant, the gNB5 can identify high priority UEs from their transmission timing. Moreover, the gNB5 may also blind decode the UE's transmissions to (ideally) pass a Cyclic Redundancy Check (CRC) to verify the priority level. In this variation, the high priority UE may first transmit a scheduling request instead of an actual transmission, and the gNB5 may identify that it has data to transmit with high priority based on the scheduling request.

[0072] Thus, as shown in Figure 2, when another UE 3-1 is already transmitting lower priority data to the gNB 5 using the same channel, the gNB 5 can determine that this lower priority transmission should be canceled and can send a COT release indicator to the UE 3-1 transmitting the lower priority transmission. The lower priority transmission is then canceled and the higher priority transmission or transmissions can continue, if necessary, during one or more subsequent FFPs without interference from the ongoing lower priority transmission from the other UE 3-1.

[0073] Different ED threshold levels for different priority data may be pre-configured and may be associated with different L1 (physical (PHY) layer) priorities that may be assigned to a particular physical uplink shared channel when resources for that channel are configured. For example, for a UE that may need to transmit high priority data (e.g., a UE that supports URLLC), at least two levels of energy detection thresholds (e.g., a high threshold "EDThreshHigh" and a low threshold "EDThreshLow") may be configured based on the L1 priority as follows: - EDThresHigh corresponding to the configured grant uplink channel with PHY L1 priority indicator set to high (e.g., "1"); and EDThresLow corresponding to the configured grant uplink channel with PHY L1 priority indicator set to low (e.g., “0”)

[0074] In this example, traffic having only two priority levels is assumed, whereas it will be appreciated that if traffic may have more than two priority levels, a different respective ED threshold level may be assigned for each priority level.

[0075] Advantageously, the gNB5 is also configured to set an FFP offset for each UE3, which in this example serves to be longer than that of the gNB5, relative to the start of the radio frame, so that the start of the COT of the gNB is different from that of the UE (value off in FIG. 2). start ) slightly before the gNB FFP start position. This effectively gives the gNB priority to acquire the channel if necessary. The minimum gap between the gNB FFP start position and the UE start position may be relatively small, enough for the gNB to transmit for a few symbols and for the UE to detect during its observation slot (e.g., 9 us). This helps avoid the possibility that the gNB may not be able to stop the UE from transmitting, which occurs when the FFP start positions of the gNB and a given UE are aligned.

[0076] FIG. 3 illustrates generally some other improved LBT-related features that can be implemented in the system of FIG.

[0077] In the example illustrated in Figure 3, the FFP for UE3 is intentionally configured to avoid the UE-initiated COT being split by the idle periods of the corresponding gNB FFP. As explained in the introduction, UE3 is not permitted to transmit during the idle periods of gNB5, and this configuration advantageously avoids complications that would otherwise arise due to avoiding transmissions during idle periods of gNB5 during the UE-initiated COT during which the UE is permitted to transmit otherwise.

[0078] In the example in FIG. 3, the UE FFP during the UE initiated COT is effectively configured to avoid the UE FFP extending (significantly) beyond the end of the corresponding gNB FFP. In particular, in the example in FIG. 3, the FFP for UE3 is configured to extend beyond any offset between the start of the gNB FFP and the start of the first UE FFP. start) (if such a starting offset is implemented) and is configured to ensure that it does not extend beyond the end of the gNB FFP.

[0079] It will be appreciated that in a variation of this feature, the UE FFP during the UE initiated COT may be configured to be longer than the length of the UE idle period to avoid the UE FFP extending beyond the end of the corresponding gNB FFP. In this variation, it can be seen that the UE FFP during the UE initiated COT is effectively configured to avoid the COT portion of the UE FFP extending beyond the end of the corresponding gNB FFP, while allowing the idle portion of the UE FFP to extend beyond the end of the gNB FFP. This effectively reduces the final COT, extending the period during which the UE is not permitted to transmit at the end of the UE FFP which corresponds to the end of the gNB FFP, while this avoids the UE initiated COT being interrupted by the idle period of the gNB FFP.

[0080] In the example illustrated in FIG. 3, the FFP of UE3 is also purposefully configured to avoid having to handle complex COT collisions, providing benefits in terms of improved reliability.

[0081] In particular, as can be seen in Figure 3, the gNB5 is configured to ensure the configuration of the UE's FFP, particularly for URLLC UEs, such that (at least) a COT portion of the UE FFP does not overlap with a COT portion of another UE's FFP. In this way, configuring the UE FFP ensures that collisions between at least a COT portion of FFPs for different UEs are avoided.

[0082] It will be appreciated that in the example of Figure 2, the FFPs for a given UE are contiguous, and thus the FFP offset and the FFP period (which is equal to the FFP duration for which the FFP is contiguous) are sufficient to define when the UE's FFP starts and ends. In Figure 3, however, the FFPs for different UEs are specifically configured to at least avoid overlapping with the UE COT. Thus, in the example of Figure 3, the period and duration of each UE FFP for each UE are configured separately.

[0083] Moreover, in the example illustrated in FIG. 3, the FFP(s) for each UE (or at least the FFP(s) per URLLC UE) may be such that all FFPs are necessarily within the FFP of the gNB5 serving that UE (i.e., the FFP for UE3 extends beyond the end of the gNB FFP). start ) (ensuring a small amount, equal to the URLLC per-UE FFP). That is, all FFPs for the UE and serving gNB are mutually configured to ensure that the gNB's FFP substantially all overlaps the one or more FFPs per UE (or at least the URLLC per-UE FFP). In the illustrated example, it will be appreciated that the FFP for UE3 extends slightly beyond the end of the gNB FFP, whereas the one or more FFPs per UE (or at least the URLLC per-UE FFP) may be mutually configured to ensure that the UE FFP is entirely within the FFP of gNB5 serving that UE.

[0084] Advantageously, in the example illustrated in FIG. 3, the periodicity of each of the gNB FFP and the UE FFP is set to a periodicity of the gNB FFP (P gNB ) is the period of the UE FFP (P UE ), so that: P UE =P gNB / Np_ UE and Np_ UE is the value of Np for a given UE.

[0085] The duration of the gNB FFP and the duration of the UE FFP are also configured to be integer multiples of some minimum period T (e.g., T=1 ms (or some minimum period defined in slots or symbols)). Thus, the gNB FFP (FFP gNB ) for UE FFP (FFP UE ) duration: FFP UE =FFP gNB / N Given by FFP UE = M_ue × T, FFP gNB = N × M_ue × T, where M_ue is an integer greater than or equal to 1.

[0086] The UE FFP Periodicity and / or UE FFP Duration (e.g., a multiple of integers N and / or Np) may be explicitly configured using dedicated RRC signaling and / or a SIB (e.g., SIB1) or may be implicitly determined in the UE 3 based on other higher layer parameters.

[0087] FIG. 4 illustrates, in a simplified manner, some variations of improved LBT-related features that can be implemented in the system of FIG.

[0088] In the example of FIG. 4, most of the UE FFPs have a duration given by UE_FFP=gNB_FFP / N (as in FIG. 3). However, one UE FFP (in this example, the first FFP) has a duration given by a start offset (off start Advantageously, the UE FFP is configured to be shorter than any other UE FFP by a value equal to: FFP UE0 =(FFP gNB / N)-off start It is.

[0089] This advantageously ensures that the last UE FFP does not extend beyond the end of the gNB FFP, even by a small amount corresponding to the starting offset, as seen in Figure 4. It will be appreciated that whereas the periodicity between the first UE FFP is shortened in the illustrated example, the duration of any UE FFP (the last UE FFP) may be shortened.

[0090] In another variation, the starting offset, the duration of the gNB FFP, and the duration of the UE FFP are all set to be equal to (or an integer multiple of) a minimum period T (e.g., T=0.5 ms (or some minimum period defined in slots or symbols)).

[0091] It will be appreciated that whereas only an FFP for a single UE 3 is shown in FIG. 4, multiple UE FFPs may be configured, for example as shown in FIG.

[0092] User Equipment (UE) Figure 5 is a block diagram illustrating the main components of a UE 3 as shown in Figure 1, and in particular, a URLLC / IIoT UE 3. It will be appreciated that while the UE 3 is described as being a URLLC / IIoT UE, the UE 3 may be configured to operate as another, non-URLLC / non-IIoT UE 3.

[0093] As shown, the UE 3 has a transceiver circuit 31 operable to transmit signals to and receive signals from the base station 5 via one or more antennas 33. The UE 3 has a controller 37 for controlling the operation of the UE 3. The controller 37 is associated with a memory 39 and coupled to the transceiver circuit 31. Although not necessarily required for its operation, the UE 3 may of course have all the usual functionality of a conventional UE 3 (user interface 35 such as touch screen / keypad / microphone / speaker and / or the like to allow direct control and interaction with a user), which may be provided by any one or any combination of hardware, software and firmware as required. The software may be pre-installed in the memory 39 and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD).

[0094] The controller 37, in this example, is configured to control the overall operation of the UE by way of program or software instructions stored in memory 39. As shown, the software instructions include, among others, an operating system 41, a communication control module 43, an LBT management module 45, a power saving management module 47, an RRC module 51, and a system information module 53.

[0095] The communication control module 43 is operable to control communication between the UE 3 and its one or more serving base stations 5 (as well as other communication devices connected to the base stations 5, such as further UEs and / or core network nodes). The communication control module 43 is configured to generally handle uplink communication over an associated uplink channel (e.g. uplink control information over a Physical Uplink Control Channel (PUCCH) and / or other uplink data over a Physical Uplink Shared Channel (PUSCH)) and to handle reception of downlink communication over an associated downlink channel (e.g. downlink control information over a Physical Downlink Control Channel (PDCCH) and / or other downlink data over a Physical Downlink Shared Channel (PDSCH)). The communication control module 43 is responsible for identifying resources to be used by the UE 3 for uplink communication (e.g. dynamically scheduled resources or semi-statically configured resources for configured grant). The communication control module 43 is responsible for activating the configured grant at the appropriate time based on either RRC signalling providing the configured grant (in the case of type 1) or L1 / L2 signalling (in the case of type 2).

[0096] The LBT management module 45 is typically responsible for managing the execution of listen-before-talk communications using the shared / unlicensed spectrum and related tasks. Those LBT related tasks include, for example, CCA in observation slots based on appropriate ED threshold levels (which may be priority-based thresholds where the UE is configured with such thresholds). The LBT related tasks also typically include initiating COT for the UE when acting as a COT initiator, receiving and responding to transmission grants from the initiating gNB when acting as a COT responder, and / or configuring the UE's FFP according to appropriate configuration parameters 47 (such as FFP offset and periodicity (and / or duration)) explicitly or implicitly indicated by the gNB 5 and maintained in the UE. If the UE 3 implements a COT cancellation mechanism such as that described in the overview, the LBT related tasks include receiving COT release indicators from the gNB and responding appropriately to them, for example by interrupting uplink transmissions and releasing the ongoing COT, before doing anything else according to the FFP configuration associated with that COT.

[0097] The RRC module 51 is responsible for receiving RRC signaling from and transmitting RRC signaling to the base station 5. The RRC signaling may be used to obtain one or more of the configuration parameters used to configure the UE's FFP, such as, for example, an offset parameter defining when the UE's FFP starts an FFP, and a periodicity parameter defining the periodicity (and duration, if the FFP is consecutive) of the UE's FFP, and / or a duration parameter defining the duration of each FFP (if required).

[0098] The system information module 53 is responsible for receiving system information from the base station 5. The received system information may include a system information block (e.g. SIB1) containing one or more of the configuration parameters used to configure the UE's FFP, such as, for example, an offset parameter defining when the UE's FFP starts the FFP, and a periodicity parameter defining the periodicity (and duration, if the FFP is consecutive) of the UE's FFP, and / or a duration parameter defining the duration of each FFP (if required).

[0099] Access network node (base station) FIG. 6 is a block diagram illustrating the main components of a base station 5 for the telecommunication system 1 shown in FIG. 1. As shown, the base station 5 has one or more antennas 53 (e.g., antenna arrays / massive antennas) for transmitting signals to and receiving signals from network nodes in the core network 7, as well as transceiver circuitry 51 for transmitting signals to and receiving signals from communication devices (such as UE 3) via a core network interface 55 (e.g., N2, N3, and other reference points / interfaces). Although not shown, the base station 5 may also be coupled to other base stations via appropriate interfaces (e.g., the so-called "Xn" interface in NR). The base station 5 has a controller 57 for controlling the operation of the base station 5. The controller 57 is associated with a memory 59. Software may be pre-installed in the memory 59 and / or downloaded, for example, via the communication network 1 or from a removable data storage device (RMD). The controller 57 is configured to control the overall operation of the base station 5 by program or software instructions stored in the memory 59, in this example.

[0100] As shown, these software instructions include, among others, an operating system 61, a communications control module 63, an LBT management module 65, a UE FFP configuration module 69, an RRC module 71, and a system information module 73.

[0101] The communication control module 63 is operable to control communication between the base station 5 and the UE 3 and other network entities connected to the base station 5. The communication control module 63 is configured to generally control the reception of uplink communications via associated uplink channels (e.g., uplink control information via a Physical Uplink Control Channel (PUCCH) and / or other uplink data via a Physical Uplink Shared Channel (PUSCH)) and / or handle the transmission of downlink communications via associated downlink channels (e.g., downlink control information via a Physical Downlink Control Channel (PDCCH) and / or other downlink data via a Physical Downlink Shared Channel (PDSCH)). The communication control module 63 is responsible for determining the resources (e.g., dynamically scheduled resources or semi-statically configured resources versus configured grant) used by the UE 3 for uplink communications. The communications control module 63 is also responsible for signaling the resources to be configured to the UE using RRC signaling, and for indicating when the grant should be activated using either RRC signaling providing the configured grant (in the case of type 1) or L1 / L2 signaling (in the case of type 2).

[0102] The LBT management module 65 is responsible for managing the execution and related tasks of listen-before-talk communication using the shared / unlicensed spectrum. Those LBT related tasks typically include CCA in observation slots, for example, based on appropriate ED threshold levels for the gNB5. The LBT related tasks also typically include initiating a COT for the gNB5 when acting as a COT initiator, receiving a transmission grant from the initiating UE when acting as a COT responder, and responding to the transmission grant, and / or configuring the gNB's FFP according to appropriate configuration parameters 67 (such as FFP offset and periodicity and / or duration) maintained in the gNB5. If the gNB5 implements a COT revocation mechanism such as the one described in the overview, the LBT related tasks include determining when a particular UE3 needs to release the COT and sending a COT release indicator to that UE3.

[0103] The UE FFP configuration module 69 is responsible for determining appropriate FFP parameters (such as FFP offset and periodicity and / or duration) for the UEs 3 served by the gNB 5, and for sending respective signaling to each UE 3 to configure the corresponding respective FFP.

[0104] The RRC module 71 is responsible for receiving and transmitting RRC signaling from the UE 3. The RRC signaling may be used to obtain one or more of the configuration parameters used to configure the UE's FFP, such as, for example, an offset parameter that defines when the UE's FFP starts the FFP, and possibly a periodicity parameter that defines the periodicity (and duration, if the FFP is consecutive) of the UE's FFP, and / or a duration parameter that defines the duration of each FFP (if required).

[0105] The system information module 73 is responsible for transmitting system information to the UEs in the base station's cell. The transmitted system information may include a system information block (e.g., SIB1) containing one or more of the configuration parameters used to configure the UE's FFP, such as, for example, an offset parameter defining when the UE's FFP starts the FFP, and possibly a periodicity parameter defining the periodicity (and duration, if the FFP is continuous) of the UE's FFP, and / or a duration parameter defining the duration of each FFP (if necessary).

[0106] UE COT release As introduced with reference to FIG. 2, a possible mechanism for canceling the uplink transmission of one UE 3-1 when another UE 3-2 has uplink data to transmit with higher priority is explained, by way of example, with reference to FIG. 7, which is a simplified timing diagram illustrating a UE COT release procedure.

[0107] 7, at S710, the gNB5 performs CCA during the observation slot and determines that the detected energy is less than the ED threshold configured at the gNB5. Thus, the gNB5 may begin COT of the gNB FFP at S712 and proceed to transmit on the downlink to one or more UEs 3.

[0108] At S714, a UE (UE1) 3-1 served by gNB5 has URLLC data to transmit at low priority. UE1 3-1 then performs CCA during an observation slot at S716 just before the FFP configured for that UE 3-1 starts and determines that the detected energy is below a low URLLC ED threshold corresponding to the low L1 (PHY) priority configured in UE1 3-1. Thus, UE1 3-1 starts the COT of its FFP at S718 and proceeds to start transmitting in uplink to gNB5 at S720 (e.g., using semi-statically configured resources of a configured grant). UE1 3-1's UE FFP has a longer FFP offset to the start of the radio frame than the gNB FFP in this example, but a shorter offset than UE2 3-2's FFP.

[0109] At S722, another UE (UE2) 3-2 served by gNB5 has URLLC data to transmit at low priority. Thus, UE2 3-2 performs CCA during an observation slot at S724 just before the FFP configured for that UE 3-2 starts and determines that the detected energy is higher than a low URLLC ED threshold corresponding to a low L1 (PHY) priority configured in UE2 3-2 due to one or more ongoing transmissions of UE1 3-1. Thus, UE2 3-2 does not start the COT of its FFP at S726, and instead its low priority URLLC transmission is effectively blocked. The UE FFP of UE2 3-2 has a longer FFP offset to the start of the radio frame than both the gNB FFP and the FFP of UE2 3-2 in this example.

[0110] At S728, the COT for UE1 3-1 ends, and UE1 3-1 enters the idle period of the corresponding FFP. At S730, UE1 3-1 still has URLLC data to transmit at low priority, so it performs CCA during the observation slot just before the next FFP for that UE3-1 starts, and determines that the detected energy is still below the low URLLC ED threshold corresponding to the low L1 (PHY) priority configured in UE1 3-1 (because UE2's transmission is disturbed and therefore the corresponding channel is still clear). Thus, UE1 3-1 starts COT during the next FFP at S732, and continues to transmit in the uplink to gNB5 at S734 (e.g., using the semi-statically configured resources of the configured grant).

[0111] In S736, UE2 3-2 now has URLLC data to transmit with high priority. Thus, UE2 3-2 performs CCA during an observation slot in S738 just before the next FFP configured for that UE 3-2 starts, and determines that the detected energy is lower than a high URLLC ED threshold corresponding to a high L1 (PHY) priority configured in UE2 3-2. Thus, even when the detected energy remains higher than a low URLLC ED threshold corresponding to a low L1 (PHY) priority (due to one or more ongoing transmissions of UE1 3-1), UE2 3-2 starts the COT of the UE's next FFP in S740, and continues to start transmitting high priority data in the uplink to gNB5 in S742 (e.g., using semi-statically configured resources of a configured grant).

[0112] The gNB5 detects the transmission of UE2 3-2 and determines in S744 that the FFP for UE1 3-1 should be released. The gNB5 then transmits an indicator to UE1 3-1 in S746 (e.g., using DCI on the PDCCH) that UE1 3-1 should release / cancel its ongoing COT. It will be appreciated that whereas the release indicator is shown as being transmitted during a downlink period during the current COT initiated by UE1, it may be received during an idle period of the current UE FFP. Moreover, whereas it is advantageous to receive the indicator as early as possible during the COT or idle period of the current FFP, it may also be received during the COT or idle period of a subsequent FFP, as the case may be.

[0113] UE1 3-1 detects the release indicator and stops its uplink transmission at S748, thereby releasing its COT and freeing the channel for further transmission of high priority URLLC data by UE2 3-2.

[0114] Once a transmission or service of UE1 3-1 is cancelled and the corresponding COT is released by the downlink release indicator, UE1 3-1 will not attempt to start another COT for the same transmission or service until the gNB5 schedules a UL transmission for that UE 3-1.

[0115] UE FFP configuration Possible methods for configuring one or more FFPs for one or more UEs served by a gNB as described with reference to Figures 2-4 will now be described by way of example only with reference to Figure 8, which is a simplified timing diagram illustrating a UE FFP configuration procedure.

[0116] As can be seen in FIG. 8, gNB5 determines the FFP configuration for one or more UEs 3 that it serves based on the FFP configuration for gNB5.

[0117] This can be done, for example, by configuring the FFP offset of each UE 3 served by the gNB 5 relative to the start of a radio frame to be longer than its own FFP offset, thereby (values ​​off in Figures 2-4) start It will be appreciated that a common offset value may be configured for two or more groups of UEs (e.g., a group of UEs of a particular type, such as URLLC UEs) and / or individual offsets may be configured.

[0118] Similarly, this may include configuring the FFP for the UE 3 to avoid a UE-initiated COT being divided by an idle period of the corresponding gNB FFP, as described with reference to FIG. 3, by ensuring that the UE FFP (or at least a COT portion of the UE FFP) does not extend beyond (or does not extend significantly beyond) the end of the gNB FFP.

[0119] In particular, the UE FFP for a URLLC UE may be configured such that (at least) the COT portion of the UE FFP does not overlap with the COT portion of the FFP of another UE. Furthermore, the UE FFP for a URLLC UE may be configured such that each FFP is entirely within the gNB FFP (or beyond the end of the egNB FFP with a starting offset). start ) may be configured to extend no longer than a small amount equal to

[0120] The periodicity between UE FFPs may be configured based on the gNB FFP to ensure that the periodicity of the gNB FFP is an integer multiple Np of the periodicity of the UE FFP as described with reference to Figures 3 or 4. Similarly, the duration between UE FFPs may be configured based on the gNB FFP to ensure that the duration of the gNB FFP is an integer multiple N of the duration of the UE FFP as described with reference to Figures 3 or 4.

[0121] At S812, the gNB 5 transmits at least a portion of the UE FFP configuration to one or more UEs 3 that it serves. FFP offset parameters for configuring the start of each UE's respective FFP during the UE-initiated COT for a radio frame may be provided to the UEs 3, for example, by dedicated RRC signaling from the gNB 5. The FFP offset parameters may alternatively or additionally be provided as common offset parameters for a group of UEs (e.g., UEs of a particular type, or UEs serving a particular service, such as URLLC) using a system information block (SIB), for example, a type 1 SIB (SIB1).

[0122] The UE FFP period may also be explicitly configured using RRC signaling and / or a SIB (e.g., SIB1), or may be implicitly determined at the UE 3 based on other higher layer parameters. For example, it will be appreciated that the UE FFP period and / or duration may be implicitly determined based on other configurations, such as a random access channel (RACH) configuration parameter or an uplink configured grant (CG) configuration parameter. If the UE FFP period is related to the gNB FFP period by a parameter Np, the UE FFP period may be configured by signaling a value of an integer N to the UE. If the UE FFP duration is related to the gNB FFP duration by a parameter N, the UE FFP duration may be configured by signaling a value of an integer N to the UE.

[0123] At S814, each UE 3 determines the UE FFP configuration and implements this configuration for subsequent LBT procedures.

[0124] Modifications and Alternatives Detailed examples of various improvements have been described above. As those skilled in the art will recognize, several modifications and alternatives may be made to the above examples while still benefiting from the invention embodied therein.

[0125] For example, while new and advantageous features of devices of a 5G telecommunications network have been described with particular reference to 5G / NR communications technologies, it will be appreciated that the advantageous features may also be implemented in devices of a telecommunications system using other communications technologies, such as other communications technologies developed as part of 3GPP. For example, while the base stations and UEs have been described as 5G base stations (gNBs) and corresponding UEs, it will be appreciated that the above-described features may apply to RAN nodes (eNBs) and UEs implementing LTE / LTE-Advanced communications technologies, or RAN nodes and UEs implementing other communications technologies developed using 3GPP-derived communications technologies.

[0126] It will be appreciated that the various improvements described above have particular utility when implemented as appropriate in URLLC UEs, and in base stations and other devices for supporting URLLC UEs. Nevertheless, the improvements may also be implemented in non-URLLC UEs and associated devices to provide similar advantages.

[0127] While examples have been described in which different ED thresholds are each associated with URLLC data having different priorities, it will be appreciated that different ED thresholds may also each be associated with many other different characteristics, such as the type of data, the originator or source of the data, the recipient or target of the data, etc.

[0128] In the above example, the base station uses 3GPP wireless communication (radio access) technology to communicate with the UE. However, in accordance with the above exemplary embodiment, any other wireless communication technology (i.e., WLAN, Wi-Fi, WiMAX, Bluetooth, etc.) may be used between the base station and the UE. The above exemplary embodiment is also applicable to "non-mobile" or generally stationary user equipment.

[0129] In the above description, for ease of understanding, the UE and base station have been described as having several discrete modules (such as a communication control module), as such, the modules may be provided for some applications, e.g., applications where existing systems have been modified to implement the invention, and for other applications, e.g., applications where the system was designed with inventive features in mind from the beginning, and the modules may be built into an overall operating system or code, and thus may not be identifiable as discrete entities.

[0130] In the above exemplary embodiment, several software modules have been described. As those skilled in the art will appreciate, the software modules may be provided in compiled or uncompiled form and may be provided to the base station, the mobility management entity, or the UE as a signal over a computer network or on a recording medium. Furthermore, the functionality performed by some or all of this software may be performed using one or more dedicated hardware circuits. However, the use of software modules is preferred to facilitate the updating of the base station or the UE to update their functionality.

[0131] Each controller may include any suitable type of processing circuitry, including, but not limited to, one or more hardware-implemented computer processors, microprocessors, Central Processing Units (CPUs), Arithmetic Logic Units (ALUs), input / output (IO) circuitry, internal memory / cache (program and / or data), processing registers, communication buses (e.g., control buses, data buses, and / or address buses), Direct Memory Access (DMA) facilities, and / or hardware or software-implemented counters, pointers, and / or timers, etc. Various other modifications will be apparent to those skilled in the art and will not be described in further detail herein.

[0132] The base station may include a "distributed" base station having a central unit "CU" and one or more separate distributed units (DU).

[0133] User equipment (or "UE", "mobile base station", "mobile device", or "wireless device") in this disclosure is an entity that connects to a network via a wireless interface.

[0134] It should be noted that the present disclosure is not limited to dedicated communication devices, but may apply to any device having communication capabilities as described in the following paragraphs.

[0135] The terms "user equipment" or "UE" (as the terms are used by 3GPP), "mobile base station," "mobile device," and "wireless device" are generally intended to be synonymous with each other and include terminals, mobile phones, smartphones, tablets, cellular IoT devices, IoT devices, and standalone mobile base stations such as machinery. It will be appreciated that the terms "mobile base station" and "mobile device" also encompass devices that remain stationary for extended periods of time.

[0136] The UE may be, for example, an item of equipment for production or manufacturing and / or an item of energy-related machinery (e.g., boilers, engines, turbines, solar panels, wind turbines, hydroelectric generators, thermal generators, nuclear generators, batteries, nuclear systems and / or related equipment, heavy electrical machinery, pumps including vacuum pumps, compressors, fans, blowers, hydraulic equipment, pneumatic equipment, metal processing machinery, manipulators, robots and / or application systems thereof, tools, moulds or dies, rolls, conveying equipment, lifting equipment, material handling equipment, textile machinery, sewing machines, printing and / or related machinery, paper converting machinery, chemical machinery, mining and / or construction machinery and / or related equipment, machinery and / or implements for agriculture, forestry, and / or fishing, safety and / or environmental protection equipment, tractors, precision bearings, chains, gears, power transmission equipment, lubrication equipment, valves, fittings, and / or application systems for any of the previously mentioned equipment or machinery, etc.).

[0137] A UE may be, for example, an item of transportation equipment (e.g., vehicles, automobiles, motorcycles, bicycles, trains, buses, carts, rickshaws, ships and other watercraft, aircraft, rockets, satellites, drones, balloons, etc.).

[0138] A UE may be, for example, an item of information and communications equipment (eg, information and communications equipment such as electronic computers and related equipment, communications and related equipment, electronic components, etc.).

[0139] The UE may be, for example, a refrigeration machine, a refrigeration application product, an item of trade and / or service industry equipment, a vending machine, an automated service machine, an office machine or equipment, a consumer electronic device (e.g., consumer electronic devices such as audio equipment, video equipment, loudspeakers, radios, televisions, microwave ovens, rice cookers, coffee makers, dishwashers, washing machines, dryers, electric fans or related devices, vacuum cleaners, etc.).

[0140] The UE may be, for example, an electrical application system or equipment (eg, an electrical application system or equipment such as an x-ray system, a particle accelerator, a radioisotope equipment, an acoustic equipment, an electromagnetic application equipment, a power application equipment, etc.).

[0141] The UE may be, for example, an electronic lamp, a lighting fixture, a measuring instrument, an analyzer, a tester, or a survey or detector (e.g., a smoke alarm, a motion sensor, a radio tag, or the like survey or detector), a watch or clock, laboratory equipment, optical equipment, medical equipment and / or systems, a weapon, an item of cutlery, or a hand tool, etc.

[0142] The UE may be, for example, a radio-equipped personal digital assistant or related equipment, such as a wireless card or module designed for attachment or insertion into another electronic device (eg, a personal computer, an electrical measuring instrument), etc.

[0143] The UE may be, for example, a device or part of a system that uses various wired and / or wireless communication technologies to provide the applications, services, and solutions described below for the “Internet of Things” (IoT).

[0144] Internet of Things devices (or "Things") may be equipped with appropriate electronics, software, sensors, and / or network connectivity that enable them to collect and exchange data with each other and with other communicating devices. IoT devices may include automated machines that follow software instructions stored in internal memory. IoT devices can operate without the need for human supervision or interaction. IoT devices may also remain stationary and / or inactive for long periods of time. IoT devices may be implemented as part of a (totally) stationary apparatus. IoT devices may also be incorporated into non-stationary apparatus (e.g., vehicles) or attached to animals or humans to be monitored / tracked.

[0145] It will be appreciated that IoT technologies may be implemented on any communication device capable of connecting to a communication network to transmit / receive data, whether such communication device is controlled by human input or by software instructions stored in memory.

[0146] It will be appreciated that an IoT device may also be referred to as a machine type communication (MTC) device or a machine-to-machine (M2M) communication device. It will be appreciated that a UE may support one or more IoT or MTC applications. Some examples of MTC applications are listed in the table below (Source: Non-Patent Document 3, the contents of which are incorporated herein by reference). This list is not comprehensive and is intended to illustrate some examples of machine type communication applications. [Table 1]

[0147] The applications, services, and solutions may be Mobile Virtual Network Operator (MVNO) emergency wireless communication systems, Private Branch eXchange (PBX) systems, PHS / digital cordless telecommunications systems, Point of Sales (POS) systems, advertising call systems, Multimedia Broadcast and Multicast Services (MBMS), Vehicle-to-Everything (V2X) systems, train radio systems, location-related services, disaster / emergency wireless communication services, community services, video streaming services, femtocell application services, Voice over LTE (VoLTE) services, billing services, radio on demand services, roaming services, behavior monitoring services, carrier / network selection services, functional restriction services, Proof of Concept (PoC) services, personal information management services, ad hoc networks / DTN (Delay Tolerant Networking) services, and the like.

[0148] Furthermore, the above-described UE categories are merely examples of applications of the technical ideas and exemplary embodiments described herein, and it should be understood that the technical ideas and exemplary embodiments are not limited to the above-described UEs, and various modifications may be made thereto.

[0149] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

[0150] The whole or part of the above disclosed exemplary embodiments can be described as follows, but is not limited thereto.

[0151] (Appendix 1) 1. A method performed by a user equipment (UE) in communication with a radio access network (RAN), comprising: maintaining information for configuring fixed frame period (FFP) timing for a listen-before-talk (LBT) procedure; When the UE has data to be transmitted, performing a clear channel assessment (CCA) to determine whether a communication channel is clear; When the CCA indicates that the communication channel is clear, initiating a channel occupation time, COT, for the UE during a subsequent FFP; commencing transmission of the data to be transmitted during the COT; receiving an indication from a node of the RAN that the transmission should be stopped; interrupting the transmission of the data in response to the received indicator; A method comprising:

[0152] (Appendix 2) 2. The method of claim 1, wherein the indication that the transmission should be stopped is received in a physical downlink control channel (PDCCH), optionally in a downlink control information (DCI) field.

[0153] (Appendix 3) 3. The method of claim 2, wherein the indicator that the transmission should be stopped comprises a single bit of the DCI field.

[0154] (Appendix 4) 3. The method of claim 1 or 2, wherein the indication that the transmission should be stopped indicates that at least one configured grant for the UE should be deactivated.

[0155] (Appendix 5) 5. The method of claim 4, wherein the indicator that the transmission should be stopped includes at least one index of a configured grant to be deactivated.

[0156] (Appendix 6) 5. The method of claim 4, wherein the indicator that the transmission should be stopped comprises a bitmap, each bit of the bitmap corresponding to a configured grant for the UE, and each bit of the bitmap being set to indicate whether the corresponding configured grant should be deactivated.

[0157] (Appendix 7) 7. The method of claim 1, wherein the indication that the transmission should be stopped is received during a COT initiated by a UE.

[0158] (Appendix 8) 8. The method of claim 1, wherein subsequent receipt of the indication that the transmission should be stopped and subsequent opportunities for transmission to attempt to initiate another COT for the same transmission are suspended until the transmission is rescheduled by the node of the RAN.

[0159] (Appendix 9) 1. A method performed by a user equipment (UE) in communication with a radio access network (RAN), comprising: maintaining information for configuring a fixed frame period (FFP) timing and a plurality of energy detection (ED) thresholds for a listen-before-talk (LBT) procedure, each ED threshold of the plurality of thresholds being associated with a different respective possible data characteristic that data transmitted by the UE may have; performing a clear channel assessment, CCA, when the UE has data to be transmitted to determine whether a communication channel is clear, the CCA including comparing a detected energy level with an ED threshold of the plurality of ED thresholds associated with a corresponding characteristic of the data to be transmitted; When the CCA indicates that the communication channel is clear, initiating a channel occupation time, COT, for the UE during a subsequent FFP; commencing transmission of the data to be transmitted during the COT; A method comprising:

[0160] (Appendix 10) 10. The method of claim 9, wherein the different possible data characteristics to which the plurality of thresholds are associated include a plurality of different priorities, and each ED threshold of the plurality of thresholds is associated with a different respective priority.

[0161] (Appendix 11) 1. A method performed by a radio access network (RAN) serving a plurality of user equipments (UEs), each UE being configured with a fixed frame period (FFP) for a listen-before-talk (LBT) procedure; receiving data transmitted by a first UE of the plurality of UEs during a first channel occupancy time, COT, initiated by the first UE during an FFP whereby the first UE of the plurality of UEs is configured; receiving a transmission by a second UE of the plurality of UEs during a second COT initiated by the second UE during an FFP whereby the second UE is configured, the transmission by the second UE being received during the first COT initiated by the first UE; determining whether transmission by the first UE should be stopped based on the transmission by the second UE; When it is determined that transmission by the first UE should be stopped, transmitting to the first UE an indication that transmission by the first UE should be stopped; A method comprising:

[0162] (Appendix 12) 12. The method of claim 11, wherein the transmission by the second UE has a higher priority than the data transmitted by the first UE.

[0163] (Appendix 13) 12. The method of claim 11, wherein the transmission by the second UE is a scheduling request for a subsequent transmission of data having a higher priority than the data transmitted by the first UE.

[0164] (Appendix 14) 1. A method performed by a radio access network (RAN) serving at least one user equipment (UE), each UE being individually configured with a fixed frame period (FFP) for a listen-before-talk (LBT) procedure; providing configuration information to each UE for at least partially configuring the timing of a respective fixed frame period (FFP) for a listen-before-talk (LBT) procedure, each of which is capable of initiating a channel occupation time (COT) of a respective FFP for that UE subject to clear channel assessment (CCA); the configuration information provided by the Radio Access Network (RAN) is configured to configure respective timings between the FFPs of each UE based on corresponding FFPs of nodes of the RAN; method.

[0165] (Appendix 15) The configuration information provided by the Radio Access Network (RAN) is based on the corresponding FFP of the node of the RAN, as follows: a respective timing between the FFPs of each UE, such that any of the FFPs for a UE is longer than a corresponding idle period between the FFPs of that UE and does not overlap with the end of the corresponding FFP of the node of the RAN; a respective timing during the FFPs of each UE, all of the FFPs for a UE occurring during the corresponding FFPs of the node of the RAN, without extending beyond the end of the corresponding FFPs of the node of the RAN for a period longer than a period corresponding to an idle period during the FFPs of the UE; a respective timing during the FFP for each UE, wherein at least a COT portion of the FFP for each UE does not coincide with at least a COT portion of the FFP for another UE served by the node of the RAN; a respective duration between at least one of the FFPs of each UE equal to the duration of the corresponding FFP of the node of the RAN divided by an integer divisor; or a respective period between the FFPs of each UE equal to the period of the corresponding FFP of the node of the RAN divided by an integer divisor; 15. The method of claim 14, configured to ensure at least one of the following:

[0166] (Appendix 16) 16. The method of claim 14 or 15, wherein the configuration information provided by the radio access network (RAN) is adjusted to configure at least one respective duration between at least one of the FFPs of each UE equal to the duration of the corresponding FFP of the node of the RAN divided by an integer divisor, and both the respective duration between at least one of the FFPs of each UE and the duration of the corresponding FFP of the node of the RAN are integer multiples of a minimum period.

[0167] (Appendix 17) 1. A method performed by a user equipment (UE) in communication with a radio access network (RAN), comprising: receiving configuration information from a RAN node for at least partially configuring a timing of a fixed frame period (FFP) for a listen-before-talk (LBT) procedure for the UE, the UE being capable of starting a respective channel occupation time (COT) during each FFP that is subject to clear channel assessment (CCA); and determining the timing of the FFP for the UE based on the received configuration information; The UE determines a timing between the UE's FFPs based on the received configuration information, the timing being based on corresponding FFPs of the RAN nodes. method.

[0168] (Appendix 18) The UE is as follows: any FFP for the UE does not overlap with the end of the corresponding FFP of the node of the RAN for a period longer than a period corresponding to an idle period between the FFPs of the UE; all of the FFPs for the UE occur during the corresponding FFPs of the nodes of the RAN without extending beyond the end of the corresponding FFPs of the nodes of the RAN for a period longer than a period corresponding to an idle period between the FFPs of the UE; at least a COT portion of the FFP for the UE does not match at least a COT portion of the FFP for another UE served by the node of the RAN; a respective duration between at least one of the FFPs of the UE equal to the duration of a corresponding FFP of the node of the RAN divided by an integer divisor; or each period during the FFP of the UE is equal to the period of the corresponding FFP of the node of the RAN divided by an integer divisor; 18. The method of claim 17, further comprising determining a timing during the FFP of the UE based on the received configuration information to which at least one of the following applies:

[0169] (Appendix 19) A user equipment (UE) in communication with a radio access network (RAN), the UE comprising: A controller and a transceiver, the controller comprising: maintaining information for configuring fixed frame period (FFP) timing and multiple energy detection (ED) thresholds for a listen-before-talk (LBT) procedure; When the UE has data to be transmitted, perform a clear channel assessment (CCA) to determine whether the communication channel is clear; When the CCA indicates that the communication channel is clear, initiating a channel occupation time, COT, for the UE during the subsequent FFP; controlling the transceiver to commence transmission of the data to be transmitted during the COT; controlling the transceiver to receive an indication from a node of the RAN that the transmission should be stopped; controlling the transceiver to interrupt the transmission of the data in response to the received indicator. The UE is configured as follows.

[0170] (Appendix 20) A user equipment (UE) in communication with a radio access network (RAN), the UE comprising: A controller and a transceiver, the controller comprising: maintaining information for configuring a fixed frame period (FFP) timing and a plurality of energy detection (ED) thresholds for a listen-before-talk (LBT) procedure, each ED threshold of the plurality of thresholds being associated with a different respective possible data characteristic that data transmitted by the UE may have; When the UE has data to be transmitted, perform a clear channel assessment (CCA) to determine whether a communication channel is clear, the CCA including comparing a detected energy level with an ED threshold of the plurality of ED thresholds associated with a corresponding characteristic of the data to be transmitted; When the CCA indicates that the communication channel is clear, initiating a channel occupation time, COT, for the UE during the subsequent FFP; controlling the transceiver to start transmitting the data to be transmitted during the COT; The UE is configured as follows.

[0171] (Appendix 21) A node of a Radio Access Network (RAN) serving a plurality of User Equipments (UEs), each UE being individually configured with a Fixed Frame Period (FFP) for a Listen-before-talk (LBT) procedure, the node of the RAN comprising: A controller and a transceiver, the controller comprising: controlling the transceiver to receive data transmitted by a first UE of the plurality of UEs during a first channel occupation time, COT, initiated by the first UE during an FFP whereby the first UE of the plurality of UEs is configured; and controlling the transceiver to receive a transmission by the second UE during a second COT initiated by the second UE during an FFP whereby a second UE of the plurality of UEs is configured, the transmission by the second UE being received during the first COT initiated by the first UE; determining whether transmission by a first UE should be stopped based on the transmission by the second UE; When it is determined that transmission by the first UE should be stopped, controlling the transceiver to transmit to the first UE an indication that transmission by the first UE should be stopped; A RAN node configured as follows:

[0172] (Appendix 22) A node of a Radio Access Network (RAN) serving a plurality of User Equipments (UEs), each UE being individually configured with a Fixed Frame Period (FFP) for a Listen-before-talk (LBT) procedure, the node of the RAN comprising: A controller and a transceiver, the controller comprising: each UE is configured to provide configuration information to each UE for at least partially configuring a timing of a fixed frame period (FFP) for a listen-before-talk (LBT) procedure, each of which is capable of initiating a channel occupation time (COT) of a fixed frame period (FFP) for that UE subject to clear channel assessment (CCA); the configuration information provided by the Radio Access Network (RAN) is configured to configure respective timings between the FFPs of each UE based on corresponding FFPs of the nodes of the RAN; A node in the RAN.

[0173] (Appendix 23) The configuration information provided by the Radio Access Network (RAN) is based on the corresponding FFP of the node of the RAN, as follows: a respective timing between the FFPs of each UE, such that any of the FFPs for a UE is longer than a corresponding idle period between the FFPs of that UE and does not overlap with the end of the corresponding FFP of the node of the RAN; a respective timing during the FFPs of each UE, all of the FFPs for a UE occurring during the corresponding FFPs of the node of the RAN, without extending beyond the end of the corresponding FFPs of the node of the RAN for a period longer than a period corresponding to an idle period during the FFPs of the UE; a respective timing during the FFP for each UE, wherein at least a COT portion of the FFP for each UE does not coincide with at least a COT portion of the FFP for another UE served by the node of the RAN; a respective duration between at least one of the FFPs of each UE equal to the duration of the corresponding FFP of the node of the RAN divided by an integer divisor; or a respective period between the FFPs of each UE equal to the period of the corresponding FFP of the node of the RAN divided by an integer divisor; 23. A node of the RAN as claimed in claim 22, configured to ensure at least one of:

[0174] (Appendix 24) A user equipment (UE) in communication with a radio access network (RAN), the UE comprising: A controller and a transceiver, the controller controls the transceiver to receive configuration information from a RAN node for at least partially configuring timing of Fixed Frame Periods (FFPs) for a Listen-before-talk (LBT) procedure for the UE, the UE being capable of initiating a respective Channel Occupancy Time (COT) during each FFP that is subject to Clear Channel Assessment (CCA), and configured to determine the timing of the FFPs for the UE based on the received configuration information; The controller is configured to determine a timing between the FFPs of the UE based on a corresponding FFP of the node of the RAN based on the received configuration information. U.E.

[0175] (Appendix 25) The controller comprises: any FFP for the UE does not overlap with the end of the corresponding FFP of the node of the RAN for a period longer than a period corresponding to an idle period between the FFPs of the UE; all of the FFPs for the UE occur during the corresponding FFPs of the nodes of the RAN without extending beyond the end of the corresponding FFPs of the nodes of the RAN for a period longer than a period corresponding to an idle period between the FFPs of the UE; at least a COT portion of the FFP for the UE does not match at least a COT portion of the FFP for another UE served by the node of the RAN; a respective duration between at least one of the FFPs of the UE equal to the duration of a corresponding FFP of the node of the RAN divided by an integer divisor; or each period during the FFP of the UE is equal to the period of the corresponding FFP of the node of the RAN divided by an integer divisor; 25. The UE of claim 24, configured to determine a timing during the FFP of the UE based on the received configuration information to which at least one of:

[0176] This application claims the benefit of priority from UK Patent Application No. 2016472.9, filed October 16, 2020, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A user equipment (UE), means for receiving configuration information from an access network node for configuring a duration of a Fixed Frame Period (FFP) that the UE starts during a period of channel occupation for a Listen-Before-Talk (LBT) procedure; means for initiating an FFP period according to said period; means for adjusting said FFP period so as not to overlap with idle periods within an FFP period during a period of channel occupancy initiated by a base station; A UE comprising:

2. The UE of claim 1 , wherein the means for adjusting adjusts the FFP period to not extend beyond an end of an idle period within an FFP period of a period of channel occupancy initiated by a base station.

3. The UE of claim 1 , wherein a corresponding transmission is avoided if the FFP period exceeds an end of an idle period within an FFP period of a period of channel occupancy initiated by a base station.

4. An access network node, The method includes: transmitting configuration information to a user equipment (UE) for setting a period of a fixed frame period (FFP) that the UE starts during a period of channel occupation for a listen-before-talk (LBT) procedure; The period is used by the UE to start an FFP period; The access network node, wherein the FFP period is adjusted by the UE so as not to overlap with idle periods within an FFP period of a period of channel occupancy initiated by a base station.

5. 1. A method in a User Equipment (UE), comprising: receiving configuration information from an access network node for configuring a duration of a Fixed Frame Period (FFP) that the UE initiates during a period of channel occupation for Listen-Before-Talk (LBT); initiating an FFP period according to said period; adjusting said FFP period so as not to overlap with idle periods within an FFP period of a period of channel occupancy initiated by a base station; A method comprising:

6. A method in an access network node, comprising: transmitting configuration information to a User Equipment (UE) for configuring a duration of a Fixed Frame Period (FFP) that the UE starts during a period of channel occupation for a Listen-Before-Talk (LBT) procedure; The period is used by the UE to start an FFP period; The method of claim 1, wherein the FFP period is adjusted by the UE to not overlap with idle periods within an FFP period of a period of channel occupancy initiated by a base station.

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