Patent Description:
Future wireless communications networks will be expected to support communications routinely and efficiently with a wider range of devices associated with a wider range of data traffic profiles and types than current systems are optimised to support. For example it is expected future wireless communications networks will be expected to efficiently support communications with devices including reduced complexity devices, machine type communication (MTC) devices, high resolution video displays, virtual reality headsets and so on. Some of these different types of devices may be deployed in very large numbers, for example low complexity devices for supporting the "The Internet of Things", and may typically be associated with the transmissions of relatively small amounts of data with relatively high latency tolerance.

An example of such a new service is referred to as Ultra Reliable Low Latency Communications (URLLC) services which, as its name suggests, requires that a data unit or packet be communicated with a high reliability and with a low communications delay. URLLC type services therefore represent a challenging example for both LTE type communications systems and <NUM>/NR communications systems.

The increasing use of different types of communications devices associated with different traffic profiles gives rise to new challenges for efficiently handling communications in wireless telecommunications systems that need to be addressed.

<CIT> discloses an apparatus for, and method of, utilising wake up signals, and coverage enhancement levels, in order to manage the status of nodes in a network. <CIT> discloses the use of paging and a group ID to be used to communicate with a group of UEs in a network. <CIT> discloses a method of managing the coverage extension level for communication between a base station and a UE, and the indication of a change in the CE level to be sent to the base station.

The network <NUM> includes a plurality of base stations <NUM> connected to a core network part <NUM>. Each base station provides a coverage area <NUM> (e.g. a cell) within which data can be communicated to and from communications devices <NUM>. Data is transmitted from the base stations <NUM> to the communications devices <NUM> within their respective coverage areas <NUM> via a radio downlink. Data is transmitted from the communications devices <NUM> to the base stations <NUM> via a radio uplink. The core network part <NUM> routes data to and from the communications devices <NUM> via the respective base stations <NUM> and provides functions such as authentication, mobility management, charging and so on. Communications devices may also be referred to as mobile stations, user equipment (UE), user terminals, mobile radios, terminal devices, and so forth. Base stations, which are an example of network infrastructure equipment / network access nodes, may also be referred to as transceiver stations / nodeBs / e-nodeBs, g-nodeBs (gNB) and so forth. In this regard different terminology is often associated with different generations of wireless telecommunications systems for elements providing broadly comparable functionality. However, example embodiments of the disclosure may be equally implemented in different generations of wireless telecommunications systems such as <NUM> or new radio as explained below, and for simplicity certain terminology may be used regardless of the underlying network architecture. That is to say, the use of a specific term in relation to certain example implementations is not intended to indicate these implementations are limited to a certain generation of network that may be most associated with that particular terminology.

<FIG> is a schematic diagram illustrating a network architecture for a new RAT wireless communications network / system <NUM> based on previously proposed approaches which may also be adapted to provide functionality in accordance with embodiments of the disclosure described herein. The new RAT network <NUM> represented in <FIG> comprises a first communication cell <NUM> and a second communication cell <NUM>. Each communication cell <NUM>, <NUM>, comprises a controlling node (centralised unit) <NUM>, <NUM> in communication with a core network component <NUM> over a respective wired or wireless link <NUM>, <NUM>. The respective controlling nodes <NUM>, <NUM> are also each in communication with a plurality of distributed units (radio access nodes / remote transmission and reception points (TRPs)) <NUM>, <NUM> in their respective cells. Again, these communications may be over respective wired or wireless links. The distributed units <NUM>, <NUM> are responsible for providing the radio access interface for communications devices connected to the network. Each distributed unit <NUM>, <NUM> has a coverage area (radio access footprint) <NUM>, <NUM> where the sum of the coverage areas of the distributed units under the control of a controlling node together define the coverage of the respective communication cells <NUM>, <NUM>. Each distributed unit <NUM>, <NUM> includes transceiver circuitry for transmission and reception of wireless signals and processor circuitry configured to control the respective distributed units <NUM>, <NUM>.

A communications device or UE <NUM> is represented in <FIG> within the coverage area of the first communication cell <NUM>. This communications device <NUM> may thus exchange signalling with the first controlling node <NUM> in the first communication cell via one of the distributed units <NUM> associated with the first communication cell <NUM>. In some cases communications for a given communications device are routed through only one of the distributed units, but it will be appreciated in some other implementations communications associated with a given communications device may be routed through more than one distributed unit, for example in a soft handover scenario and other scenarios.

Thus example embodiments of the disclosure as discussed herein may be implemented in wireless telecommunication systems / networks according to various different architectures, such as the example architectures shown in <FIG> and <FIG>. It will thus be appreciated the specific wireless communications architecture in any given implementation is not of primary significance to the principles described herein. In this regard, example embodiments of the disclosure may be described generally in the context of communications between network infrastructure equipment / access nodes and a communications device, wherein the specific nature of the network infrastructure equipment / access node and the communications device will depend on the network infrastructure for the implementation at hand. For example, in some scenarios the network infrastructure equipment / access node may comprise a base station, such as an LTE-type base station <NUM> as shown in <FIG> which is adapted to provide functionality in accordance with the principles described herein, and in other examples the network infrastructure equipment / access node may comprise a control unit / controlling node <NUM>, <NUM> and / or a TRP <NUM>, <NUM> of the kind shown in <FIG> which is adapted to provide functionality in accordance with the principles described herein.

A better appreciation provided by the example embodiments can be gained from reviewing a proposed wireless access interface according to 3GPP LTE/<NUM> and NR/<NUM>. However it will be appreciated that the wireless access interface provides physical communications resources including shared channels for both uplink and the downlink which may be accessed by communicating appropriate control signalling as those acquainted with LTE will appreciate.

A more detailed illustration of a UE <NUM> and an example network infrastructure equipment <NUM>, which may be thought of as a gNB <NUM> or a combination of a controlling node <NUM> and TRP <NUM>, is presented in <FIG>. As shown in <FIG>, the UE <NUM> is shown to transmit uplink data to the infrastructure equipment <NUM> via grant free resources of a wireless access interface as illustrated generally by an arrow <NUM>. As with <FIG> and <FIG>, the infrastructure equipment <NUM> is connected to a core network <NUM> via an interface <NUM> to a controller <NUM> of the infrastructure equipment <NUM>. The infrastructure equipment <NUM> includes a receiver <NUM> connected to an antenna <NUM> and a transmitter <NUM> connected to the antenna <NUM>. Correspondingly, the UE <NUM> includes a controller <NUM> connected to a receiver <NUM> which receives signals from an antenna <NUM> and a transmitter <NUM> also connected to the antenna <NUM>.

The controller <NUM> is configured to control the infrastructure equipment <NUM> and may comprise processor circuitry which may in turn comprise various sub-units / sub-circuits for providing functionality as explained further herein. These sub-units may be implemented as discrete hardware elements or as appropriately configured functions of the processor circuitry. Thus the controller <NUM> may comprise circuitry which is suitably configured / programmed to provide the desired functionality using conventional programming / configuration techniques for equipment in wireless telecommunications systems. The transmitter <NUM> and the receiver <NUM> may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter <NUM>, the receiver <NUM> and the controller <NUM> are schematically shown in <FIG> as separate elements for ease of representation. However, it will be appreciated that the functionality of these elements can be provided in various different ways, for example using one or more suitably programmed programmable computer(s), or one or more suitably configured application-specific integrated circuit(s) / circuitry / chip(s) / chipset(s). As will be appreciated the infrastructure equipment <NUM> will in general comprise various other elements associated with its operating functionality.

Correspondingly, the controller <NUM> of the UE <NUM> is configured to control the transmitter <NUM> and the receiver <NUM> and may comprise processor circuitry which may in turn comprise various sub-units / sub-circuits for providing functionality as explained further herein. These sub-units may be implemented as discrete hardware elements or as appropriately configured functions of the processor circuitry. Thus the controller <NUM> may comprise circuitry which is suitably configured / programmed to provide the desired functionality using conventional programming / configuration techniques for equipment in wireless telecommunications systems. Likewise, the transmitter <NUM> and the receiver <NUM> may comprise signal processing and radio frequency filters, amplifiers and circuitry in accordance with conventional arrangements. The transmitter <NUM>, receiver <NUM> and controller <NUM> are schematically shown in <FIG> as separate elements for ease of representation. However, it will be appreciated that the functionality of these elements can be provided in various different ways, for example using one or more suitably programmed programmable computer(s), or one or more suitably configured application-specific integrated circuit(s) / circuitry / chip(s) / chipset(s). As will be appreciated the communications device <NUM> will in general comprise various other elements associated with its operating functionality, for example a power source, user interface, and so forth, but these are not shown in <FIG> in the interests of simplicity.

Systems incorporating NR technology are expected to support different services (or types of services), which may be characterised by different requirements for latency, data rate and/or reliability. For example, Enhanced Mobile Broadband (eMBB) services are characterised by high capacity with a requirement to support up to <NUM> Gb/s. The requirements for Ultra Reliable & Low Latency Communications (URLLC) [<NUM>] services are for a reliability of <NUM> - <NUM>-<NUM> (<NUM> %) or higher for one transmission of a <NUM> byte packet with a user plane latency of <NUM> [<NUM>]. In some scenarios, there may be a requirement for a reliability of <NUM> - <NUM>-<NUM> (<NUM> %) or higher with either <NUM> or <NUM> of user plane latency. Massive Machine Type Communications (mMTC) is another example of a service which may be supported by NR-based communications networks.

In addition, systems may be expected to support further enhancements related to Industrial Internet of Things (IIoT) in order to support services with new requirements of high availability, high reliability, low latency, and in some cases, high-accuracy positioning.

Industrial automation, energy power distribution and intelligent transport systems are examples of new use cases for Industrial Internet of Things (IIoT). In an example of industrial automation, the system may involve different distributed components working together. These components may include sensors, virtualized hardware controllers and autonomous robots, which may be capable of initiating actions or reacting to critical events occurring within a factory and communicating over a local area network.

The UEs in the network may therefore be expected to handle a mixture of different traffic, for example, associated with different applications and potentially different quality of service requirements (such as maximum latency, reliability, packet sizes, throughput). Some messages for transmission may be time sensitive and be associated with strict deadlines and the communications network may therefore be required to provide time sensitive networking (TSN).

In order to permit a communications device to transmit data associated with multiple traffic classes in a timely manner, multiple configured grants/semi-persistent scheduling (SPS) grants may be required in order to provide more flexibility while avoiding excessive dynamic downlink control signalling.

One of the aspects of URLLC being developed for <NUM>/NR to support IIoT is a requirement for URLLC to provide a low latency, measured from the ingress of a layer <NUM> packet to its egress from the network, with a proposed target of <NUM> with a reliability of <NUM>%, and later it has been extended to <NUM> with a reliability of <NUM>,<NUM>%. This is required in order to support the services for IIoT which require high availability, high reliability, low latency, and in some cases, high-accuracy positioning [<NUM>]. Furthermore, one of the requirements for communicating uplink data from a UE is to manage intra-UE packet prioritization and multiplexing. This is a requirement to prioritise the communication of uplink data and control packets from different categories of traffic within the UE. A better appreciation of the generation of uplink data of different logical types will be provided in the following section.

Paging permits the transmission downlink data without requiring each communications device <NUM> to continuously monitor downlink data channels (such as physical downlink shared channels, PDSCHs). Instead, each communications device <NUM> determines a sequence of time windows, which may be referred as paging frames, during which it monitors a subset of communications resources, such as a paging channel. The sequence of time windows or paging frames for each communications device <NUM> is also known to the infrastructure equipment <NUM>.

In some examples, paging frames may occur in subframes having subframe number SFN, where equation (<NUM>) is satisfied: <MAT> where UE_ID is an identifier of the communications device <NUM>, such as a temporary mobile subscriber identity (TMSI), which may be a <NUM>-S-TMSI, SFN is a subframe number, N is a number of paging groups, and T and PF_offset are parameters configured (that is, indicated in transmitted control messages) by the network.

When the infrastructure equipment <NUM> determines that it has downlink data to transmit to the communications device <NUM>, it determines the next paging frame when the communications device <NUM> will monitor the paging channel.

The infrastructure equipment <NUM> may determine that it has downlink data to transmit in response to receiving the downlink data from the core network <NUM>, or based on a generation of data by the infrastructure equipment <NUM> for transmission to the communications device <NUM>.

During the next paging frame, it transmits a paging message to the communications device <NUM>. The paging message comprises an indication of an identity of the communications device <NUM> and an indication that the infrastructure equipment <NUM> has downlink data for transmission to the communications device <NUM>.

In response to receiving the paging message, the communications device <NUM> transmits a response message to the infrastructure equipment <NUM>. Subsequently, the communications device <NUM> monitors communications resources on which the infrastructure equipment <NUM> transmits the downlink data.

It will be appreciated that intermediate steps for, for example, establishing or resuming an RRC connection by means of a random access procedure may occur between the transmission of the paging message and the transmission of the data. The response message may be transmitted on a random access channel, such as on a physical random access channel (PRACH).

Different communications devices may be configured with different sets of paging frames, in order to avoid congestion on the paging channel and on the PRACH.

It may be that, in accordance with conventional techniques, two or more communications devices select a same instance of the PRACH to transmit a random access request. The random access requests may be in response to paging or in response to a determination by the communications device that it has uplink data to transmit.

In order to increase the probability of a successful random access procedure, the random access request may comprise an element, such as a random access preamble, randomly selected by the communications device. Each communications devices selects, at random and independently of the random selection by the other communications device(s), from a number of predetermined RACH preambles. Thus, even if two communications devices transmit on a same PRACH instance, their random access requests may still be decoded by the infrastructure equipment if they comprise different preambles.

Nevertheless, there remains a possibility that both communications devices select the same preamble for transmission on the same PRACH instance. In such circumstances, it is highly likely that one or both random access attempts will fail.

<FIG> illustrates a message sequence chart for the transmission of downlink data to multiple communications devices, in accordance with conventional techniques for transmitting downlink data.

It will be appreciated that certain steps and messages have been omitted or conflated for conciseness.

<FIG> shows three communications devices, UE1 104a, UE2 104b and UE3 104c, and an infrastructure equipment, such as a gNB <NUM>.

At steps S402, S404 and S406 respectively, the gNB <NUM> configures each of UE1 104a, 104b and 104c with a paging configuration. The paging configuration permits the communications devices to determine their subsequent paging frames. In the example of <FIG>, the paging configuration may be carried out while the communications devices are in an RRC connected mode, although the establishment of the RRC connections is not shown for conciseness.

The paging configuration may comprise an indication of a temporary identifier, such as a TMSI, based on which each UE or communications device (and similarly, the infrastructure equipment <NUM>) is able to determine subsequent paging frames, for example, based on a modulo operation on the TMSI value. The TMSI value and corresponding DRX cycle for monitoring the downlink paging channel may be allocated by the core network; this step is omitted from <FIG> for conciseness.

Subsequently, at steps S408, S410 and S412, the infrastructure equipment <NUM> transmits an RRC suspend message to each of the communications device 104a, 104b, 104c, having the effect that the RRC connection for each communications device is suspended. The communications devices may thus enter the RRC INACTIVE state from the RRC CONNECTED state. In the RRC INACTIVE state, state associated with the RRC connection is maintained at the communications devices and the infrastructure equipment. The respective RRC connections are not active and the communications devices monitor a paging channel during respective paging frames in accordance with the configuration at steps S402, S404 and S406 to determine if the infrastructure equipment has downlink data for transmission to it. Uplink data cannot be transmitted during the RRC INACTIVE state.

In general, the RRC INACTIVE state may reduce the requirements on the communications device to monitor downlink communications resources, so that its power consumption is reduced, compared with when in the RRC CONNECTED mode.

Thus, the communications devices 104a, 104b, 104c enter a state in which monitoring requirements are reduced and/or power consumption may be reduced, relative to an active state. In some embodiments, the new state is the RRC INACTIVE state.

Subsequently, the communications devices 104a, 104b, 104c monitor the paging channel during their respective paging frames. In the example of <FIG>, the paging frames (shown by dashed rectangles <NUM>, <NUM>, <NUM>) for the three communications devices do not overlap.

At step S414, the infrastructure equipment <NUM> receives downlink data for transmission to the three communications devices 104a, 104b, 104c. In response, it determines the next instance 450b of the paging frames <NUM> for paging the first communications device 104a, and similarly determines instances 452b and 454b for paging the second and third communications device 104b, 104c.

During the determined paging frames 450b, 452b, 454b, the infrastructure equipment <NUM> transmits paging messages to the first, second and third communications devices 104a, 104b, 104c at steps S416, S420 and S418, respectively.

Accordingly, (and with intervening steps and messages not shown) at steps S422, S426 and S424, the infrastructure equipment transmits the downlink data to the first, second and third communications devices 104a, 104b, 104c, respectively.

There remains, however, a need to provide low latency delivery of data from an infrastructure equipment to one or more communications devices which are in a reduced power mode, such as the RRC INACTIVE state.

In one application a group of UEs are operating as part of a financial service such as a trading floor and require rapid paging to receive contemporaneously the latest financial information. As such there is a desire for each of the UEs which are configured with a conventional pattern of paging frames which are determined by the UE using the above technique to be re-configured when the UEs are on the trading floor to monitor the same pattern of trading feeds so that a gNB providing a cell serving the trading floor can page all the UEs in the group and therefore transfer down link data more rapidly compared with going to each of the UEs separately as would be the case for a conventional operation in which the UEs determined their paging frames.

Accordingly, the present disclosure provides a method of operating an infrastructure equipment of a wireless communications network, the method comprising transmitting control information via a wireless access interface provided by the wireless communications network to a communications device to configure the communications device to receive paging messages as part of a group of one or more communications devices, the communications device being configured by the control information from a first state in which the communications device monitors a pattern of paging frames of the wireless access interface for receiving paging messages determined by the communications device to a second state in which the communications device is configured to monitor the same pattern of paging frames of the wireless access interface for receiving paging messages as the group of one or more communications devices. <FIG> illustrates a message sequence chart showing the transmission of downlink data in accordance with embodiments of the present technique.

The process starts at step S502 with a selection of a group of a plurality of communications devices to receive fast downlink data transmissions. The group of communications devices may be selected according to an associated network slice or subscription parameters (for example, that they all subscribe to a certain service, or are associated with a certain commercial entity). For example, the communications devices may be selected based on their being associated with a subscription for low latency financial information. The financial information may comprise stock exchange prices, or foreign exchange rates, trading information and/or any other similar information.

In some embodiments, location determination is based on measurements of an indoor beacon, device-to-device proximity detection in respect of one or more additional communications devices, and/or radio resource management (RRM) measurements.

In some embodiments, the communications device may be selected as a group member based on an application associated with (e.g. running on) the communications device.

In some embodiments, the criteria for inclusion in the group may be pre-determined and known to the communications devices. In some embodiments, the criteria are pre-determined at the infrastructure equipment <NUM> and not at the communications devices.

In the example of <FIG>, first, second and third communications device 104a, 104b and 104c are selected at step S502.

In some embodiments, step S502 and the subsequent configuration steps described below may occur multiple times, such as in response to determining that a communications device <NUM> has newly satisfied the requirements for selection. For example, the infrastructure equipment may determine that a communications device <NUM> has moved to be within a pre-determined area, such as within a coverage area of the cell <NUM> controlled by the infrastructure equipment <NUM>. The cell <NUM> may correspond, for example, to a trading floor of a stock exchange. In response, the infrastructure equipment <NUM> may perform step S502 and subsequent configuration steps as described below.

At steps S504, S506 and S508 respectively, each of the selected communications devices 104a, 104b, 104c are configured with a same, synchronised, sequence of paging frames by the infrastructure equipment <NUM>.

In some embodiments, the configuration of the synchronised paging frames comprises transmitting to each of the selected communications devices an indication of a value to use in the determination of paging frames, in place of a temporary identifier, such that the paging frames, when determined using each of the values, are the same (i.e. synchronised with respect to each other).

In some embodiments, each value is different; in some embodiments, the same value is used, and in some such embodiments, the value is zero.

For example, in some embodiments, at each of step S504, S506 and S508, the infrastructure equipment <NUM> transmits a paging configuration message indicating that the value <NUM> (zero) is to be used in place of the <NUM>-S-TMSI (i.e. as the value UE_ID) in determining the paging frames for each of the selected communications devices 104a, 104b, 104c.

In some embodiments, the value is a predetermined value to be used when no temporary identifier has been assigned.

In some embodiments, the configuration of the same paging frames is by assigning each of the selected communications devices with a temporary identifier to use in the determination of paging frames such that the paging frames, when determined using each of the values (for example, in accordance with conventional techniques and/or using equation (<NUM>) above), are the same.

In some embodiments, the configuration of the same paging frames is by assigning each of the selected communications devices with a parameter UE_ID_MOD_N to use in the equation (<NUM>) in place of the expression (UE_ID mod N). Thus, paging frames are determined according to equation (<NUM>): <MAT>.

In the example of <FIG>, at each of steps S510, S512 and S514, an RRC connection associated with a respective one of the communications device 104a, 104b and 104c are suspended and the communications devices enter the RRC INACTIVE state.

In some embodiments, the RRC connections are terminated or released, and the new state is the RRC IDLE state. In the RRC IDLE state, no state associated with the (most recent) RRC connection of the communications device is maintained at the infrastructure equipment.

In any case, while no longer in the RRC CONNECTED state, the communications devices 104a, 104b, 104c monitor the downlink paging channel in synchronised paging frames determined in accordance with the configuration at steps S504, S506, S508 described above. All of the selected communications devices <NUM> which are not in the RRC CONNECTED state monitor the paging channel at the same paging frames. In the example of <FIG>, these are shown by dashed rectangles at times t1 and t2.

At step S516, the infrastructure equipment <NUM> determines that it has (or will soon receive or generate) downlink data to transmit to each of the communications devices 104a, 104b, 104c in the group. In some embodiments, the same downlink data is to be transmitted to each of the communications devices. In some embodiments, different downlink data is to be transmitted to each of the communications devices.

In the example of <FIG>, the determination at step S516 is based on receiving, while the communications devices are in the RRC INACTIVE state, downlink data from the core network <NUM>.

In some embodiments, the determination is based on generating at the infrastructure equipment <NUM>, downlink data for transmission to the communications devices.

In some embodiments, the determination is based on receiving by the infrastructure equipment <NUM> a paging message from the core network <NUM>. In some such embodiments, the communications devices 104a, 104b, 104c may be in the RRC IDLE state.

In response to the determination at step S516, the infrastructure equipment <NUM> determines that the next synchronised paging frame to be monitored by the communications devices 104a, 104b, 104c is at time t2. As a result of the paging configuration at steps S504, S506, S508, the next synchronised paging frame to be monitored by one of the selected communications devices at time t2 will also be monitored by the other selected communications devices.

At step S518, the infrastructure equipment <NUM> transmits in the determined next paging frame a paging message <NUM>. The paging message <NUM> comprises an indication that downlink data is to be transmitted to each of the communications devices 104a, 104b, 104c.

After receiving the paging message <NUM>, each of the communications devices 104a, 104b, 104c enters the RRC CONNECTED state and receives, at steps S530, S532, and S534, the downlink data <NUM>, <NUM>, <NUM>, respectively.

In some embodiments, the transition from RRC INACTIVE or RRC IDLE to RRC CONNECTED in response to receiving the paging message <NUM> is automatic, and the communications device enters the RRC CONNECTED mode without additional transmissions.

In some embodiments, each communications device responds to the paging message <NUM> by transmitting one or more messages before receiving the data, for example in a conventional manner. In some embodiments, in response to receiving the paging message <NUM>, a communications device transmits a random access message on the PRACH to initiate a random access procedure. The random access procedure results in the establishment or resumption of an RRC connection, and the subsequent reception of the downlink data.

In some embodiments, one or more of the selected communications devices performs a random access procedure prior to receiving the downlink data, and one or more of the selected communications devices enters the RRC CONNECTED state automatically. In some such embodiments, the infrastructure equipment <NUM> may transmit (for example, as part of the configuration steps S504, S506, S508) a random access permission indication to each of the selected communications devices to indicate that one of the following applies to the communications device:.

In some embodiments, where the random access permission indication indicates that the communications device is required to initiate a random access procedure, the random access permission indication may further indicate that the communications device is to perform a <NUM>-step RACH or a <NUM>-step RACH procedure.

In response to the indication and the reception of a paging message transmitted during a synchronised paging frame, each communications device may proceed in accordance with the configuration.

In some embodiments, the infrastructure equipment <NUM> configures exactly one of the selected communications devices to be required to initiate a random access procedure in response to a paging message transmitted during a synchronised paging frame.

In the example of <FIG>, the first communications device 104a responds to the paging message <NUM> by initiating a <NUM>-step RACH procedure by transmitting, at step S520, a random access message <NUM> on the PRACH. In response to receiving the random access message <NUM>, the infrastructure equipment <NUM> transmits a random access response <NUM> at step S522.

At step S524, in response to receiving the random access response <NUM>, the communications device 104a transmits a `message <NUM>', such as an RRC Resume request message <NUM>. At step S526, the infrastructure equipment <NUM> transmits an RRC Resume message <NUM> in response to receiving the RRC Resume request message <NUM>.

At step S528, in response to receiving the RRC Resume message <NUM>, the communications device 104a transmits an RRC Resume Complete message <NUM>. The communications device 104a enters RRC CONNECTED state.

The first communications device 104a therefore receives the data <NUM> in step S530.

In the example of <FIG>, the second and third communications devices 104b, 104c are configured to enter the RRC CONNECTED state without completing a random access procedure. Thus, as indicated by the dashed double-headed arrows, they enter the RRC CONNECTED state and, at steps S532 and S534, receive the data <NUM>, <NUM> without completing a random access procedure. Details of this step are provided below.

For the purposes of clarity, steps are shown sequentially in <FIG>; however, this may not be the case in some embodiments. In particular, the second and third communications devices 104b, 104c may enter the RRC CONNECTED mode directly in response to receiving the paging message <NUM>, and may thus receive the data <NUM>, <NUM> earlier than is shown in the sequence of <FIG>. For example, they may receive the data prior to the completion of the random access procedure of the first communications device 104a.

It should also be readily apparent that while the sequence chart of <FIG> broadly illustrates the sequence of messages and actions as time progresses from top to bottom, as with all message sequence charts for the present application, the (vertical) time axis is not to scale.

The process of <FIG> may be repeated for different selected groups of communications devices. In some embodiments, the steps of the process of <FIG> may be repeated in respect of a given communications device, whereby different synchronised paging frames may be configured for different selected groups to which the communications device belongs, or for different traffic types (for example, for downlink data having different quality of service requirements, or associated with different services).

As described above, in some embodiments, one or more of the communications devices 104a, 104b, 104c may enter the RRC CONNECTED state directly in response to receiving the paging message <NUM>.

In some embodiments, one or more of the communications devices 104a, 104b, 104c may have been in a first state in which they were configured with paging frames which are not synchronised with those of the other selected communications devices. This may be, for example, prior to step S502. In some such embodiments, the non-synchronised paging frames may have been configured in accordance with conventional techniques, such as those illustrated in <FIG> and described above, for example, based on the assigned <NUM>-S-TMSI, when the <NUM>-S-TMSI is assigned in a manner which does not ensure synchronised paging frames for the selected communications devices.

In response to receiving the configuration at steps S504, S506, S508, the communications devices may enter a second state in which the synchronised paging frames are configured.

In some embodiments, a communications device may be configured only in the second state by means of one of the steps S504, S506, S508 if, for example, on initial connection to the wireless communications network (such as after being switched on or reset) it is determined to satisfy the criteria for being configured in the second state.

In some embodiments, the synchronised paging frames are used for all paging message for the communications devices and as such, replace any non-synchronised paging frames. Therefore, in the second state, the communications device <NUM> may monitor only synchronised paging frames.

In some embodiments, the synchronised paging frames are configured in addition to non-synchronised paging frames. In the second state, the communications device <NUM> may monitor synchronised paging frames and non-synchronised paging frames. The infrastructure equipment <NUM> may determine, in such embodiments, whether to page the communications devices within the selected group using a synchronised paging frame, or a non-synchronised paging frame. This determination may be based on a latency requirement associated with the downlink data (so that, downlink data having a maximum permitted latency below a predetermined threshold is notified using a synchronised paging frame). Additionally or alternatively, the determination may be based on whether application data is to be transmitted only to a single communications device, or to all communications devices within the selected group. Where the data is to be transmitted to all communications devices within the selected group, then the infrastructure equipment may use a next synchronised paging frame. This may ensure that the data is transmitted with improved (i.e. lower) latency and/or making more efficient use of the communications resources of the wireless access interface to all communications devices, collectively, compared with using conventional paging techniques for each communications device.

In the example shown in <FIG>, the configuration of the synchronised paging frames is carried out separately from the suspension of the RRC connections. However, in some embodiments, these steps may be combined. That is, for example, at step S514 in which the infrastructure equipment <NUM> transmits to the first communications device 104a a message indicating that the RRC connection is to be suspended or released, the same message may also comprise an indication of the synchronised paging frames, such as an indication of the temporary identifier as described above.

Thus, in some embodiments, steps S504 and S514 may be combined, steps S506 and S512 may be combined and/or steps S508 and S510 may be combined. As part of one or more of the configuration steps S504, S506, S508, the infrastructure equipment <NUM> may, in addition, indicate to the respective communications device <NUM> whether, in response to subsequently receiving a paging message, one or both of a random access (RACH) procedure and/or an RRC Resume/RRC establishment procedure are to be skipped prior to the RRC connection being established or resumed.

In some embodiments, the selected plurality of communications devices may comprise all communications devices currently having the same serving cell. For example, in some embodiments, access to a particular cell may be restricted a priori to communications devices within the selected group, for example, based on an associated subscription. For example, the infrastructure equipment <NUM> may be provided for the exclusive use of employees at a particular company, or participants in a particular activity at a particular location (for example, traders at a stock market). Each communications device associated with such employees or participants may be associated with a subscription (known to the wireless communications network) permitting the communications device to access a cell provided by the infrastructure equipment <NUM>.

In some embodiments, the configuration of the synchronised paging frames may be by means of a broadcast transmission by the infrastructure equipment <NUM>. The broadcast transmission may indicate a UE_ID value for use in a conventional paging frame calculation technique, such as in accordance with equation (<NUM>) above. The broadcast transmission may be a system information message transmitted on a broadcast channel.

In some embodiments, at steps S504, S506, and S508, the infrastructure equipment <NUM> may additionally or alternatively indicate whether the respective communications device 104a, 104b, 104c is to monitor the synchronised paging frames, paging frames determined in a conventional manner, or both.

The infrastructure equipment <NUM> may subsequently transmit paging messages to a communications device in one or more paging frames which the respective communications device has been indicated to monitor in step S504, S506 or S508.

In some embodiments of the present technique, a communications device (such as one of the communications devices 104a, 104b, 104c) may transmit a synchronised paging capability indication to the infrastructure equipment that indicates that the communications device is capable of being configured to monitor synchronised paging frames. For example, the synchronised paging capability may indicate that the communications device will, in response to the configuration described at steps S504, S506 or S508 above, monitor the synchronised paging frames at t1 and t2, as described above. In addition, the communications device <NUM> may also indicate its capability to skip the RACH procedure and/or the RRC Resume/Establishment procedure in response to receiving the paging message.

In the example of <FIG>, all of the selected group of communications devices <NUM> are in the RRC INACTIVE state when the infrastructure equipment <NUM> determines that there is downlink data to send at step S516. In some embodiments, the infrastructure equipment <NUM> may determine for which of the selected group of communications devices <NUM> there is data to be transmitted, and of those, which state each is in.

For example, in another example, the selected group of communications devices may comprise the three communications devices 104a, 104b, 104c as well as one or more additional communications devices. When the determination at step S516 is made, the infrastructure equipment may determine that each of the additional communications devices are either in the RRC CONNECTED state (in which case the data may be transmitted using conventional techniques for downlink data transmission during RRC CONNECTED state), or there may be no data to be transmitted to that communications device. The infrastructure equipment <NUM> may transmit the data to the three communications devices illustrated in <FIG> as described above.

In some embodiments, the infrastructure equipment may treat communications devices in the RRC IDLE mode in the same manner as communications devices in the RRC INACTIVE state. In some embodiments, the infrastructure equipment may transmit separate paging message to communications devices in the RRC IDLE state and to communications devices in RRC INACTIVE state.

In some embodiments, the same data may be for transmission to all communications devices in the selected group, in which case the determination may be made only in respect of the RRC state of each device in the group.

<FIG> is a message sequence chart showing a transmission of downlink data in accordance with embodiments of the present technique.

At the start of the sequence shown in <FIG>, none of the three communications devices 104a, 104b, 104c are in the RRC CONNECTED state. For example, all three may be in the RRC INACTIVE state or in the RRC IDLE state. In some embodiments, some or all of the steps S502 to S514 as shown in <FIG> and described above may have occurred prior to the sequence shown in <FIG>.

In addition, at least the second and third communications devices 104b, 104c are configured to monitor via a receiver for a wake-up trigger message, which may be transmitted by another communications device.

The configuration may comprise determining a nature (e.g. modulation scheme, message contents, encoding) of the wake-up trigger message, and means for its transmission (e.g. carrier frequency, schedule of possible time(s) of transmission).

In some embodiments, the periodicity of potential times of transmission of the wake-up trigger message is smaller than that of the non-synchronised paging frame occurrences monitored by the second and/or third communications devices 104b, 104c.

Alternatively, in some embodiments, the potential times of transmission of the wake-up trigger are aperiodic. In some embodiments, the wake-up trigger message is transmitted by the communications device 104a multiple times in response to a trigger event (e.g. the receipt of the paging message <NUM>). The multiple transmissions may be in accordance with a predetermined rule known to both the first communications device 104a and the other communications devices 104b, 104c.

Similarly, at least the first communications device 104a is configured with (i.e. determines) the nature and means for transmission for the wake-up trigger message.

In some embodiments, the configuration is by means of the transmission by the infrastructure equipment <NUM> and receipt by the communications device <NUM> of a configuration message, such as the messages transmitted in step S504-S508 described above.

In the example of <FIG>, at least the first communications device 104a is monitoring paging frames which are not synchronised with those of the other communications devices 104b, 104c. For example, the paging frame occurrence 450c may be determined based on an assigned TMSI, as described above in the example of <FIG>. In some embodiments, as described above, the monitoring of the non-synchronised paging frames may be in addition to the monitoring of the synchronised paging frames.

In some embodiments, steps S504-S508 are omitted, such that each communications device <NUM> is configured to monitor only non-synchronised paging frames, for example in accordance with conventional techniques.

In the example of <FIG>, at step S702, the infrastructure equipment receives data from the core network <NUM> (not shown) for transmission to the three communications devices 104a, 104b, 104c. It will be appreciated, as described above, that the downlink data may also be generated by the infrastructure equipment <NUM>.

In response to the determination at step S702 that there is downlink data to be transmitted, the infrastructure equipment <NUM> determines the next paging frame to be monitored by any of the communications devices 104a, 104b, 104c. In the example of <FIG>, this is determined to be the paging frame occurrence 450c being monitored by the first communications device 104a.

In response to this determination, at step S704, the infrastructure equipment <NUM> transmits a paging message <NUM> to the first communications device 104a, such that it is received within the paging frame occurrence 450c.

The paging message <NUM> comprises an indication that the infrastructure equipment <NUM> has downlink data to be transmitted to each of the three communications devices 104a, 104b, 104c. Alternatively, in some embodiments, the paging message <NUM> may indicate simply that the infrastructure equipment <NUM> has downlink data to be transmitted to at least one communications device in addition to the first communications device 104a.

In response to receiving the paging message <NUM>, the first communications devices 104a transmits, at step S706, a wake-up trigger message <NUM>. This is received by the second and third communications devices 104b, 104c.

In response to receiving the wake-up trigger message <NUM>, the second and third communications devices 104b, 104c leave the RRC INACTIVE state. The second and third communications devices 104b, 104c may perform either.

The second and third communications devices 104b, 104c may then monitor a downlink channel for a transmission of data by the infrastructure equipment <NUM>. The infrastructure equipment <NUM> may decide to omit the random access procedure if, for example, time alignment does not change compared to previous RA procedure. This may be because, for example, one or both of the communications devices 104b, 104c are stationary. The infrastructure equipment <NUM> may configure one or both of the communications devices 104b, 104c to skip an RRC Resume procedure if infrastructure equipment <NUM> determines that there is no security risk associated with such a modified procedure for this UE and authentication token/ new key generation is not required.

Subsequently, at step S708, the infrastructure equipment <NUM> transmits the data <NUM> to the first, second and third communications devices 104a, 104b, 104c.

In the example of <FIG>, no additional transmissions occur to or by the communications devices between the transmission of the wake-up trigger message <NUM> and the transmission of the data <NUM>. In some embodiments, however, each of the communications devices may carry out a procedure to request the resumption or establishment of an RRC connection with the infrastructure equipment <NUM>, for example by means of a <NUM>-step or <NUM>-step RACH procedure.

In the example of <FIG>, a single transmission is made at step S708 of the data <NUM>.

In some embodiments, the data <NUM> is transmitted in one or more separate messages, each to one or more of the communications devices.

In some embodiments, in response to a paging message, a communications device <NUM> performs a random access procedure in order to request establishment or resumption of an RRC connection, for example as illustrated in steps S520 to S528 of <FIG>, and described above.

One use of a RACH procedure is to determine a timing advance for uplink transmissions by the communications device. In some embodiments, the communications devices <NUM> determines that a timing advance determined while the RRC connection was active (i.e. not suspended) is still valid, based on a determination that a distance moved by the communications device <NUM> since the timing advance was previously determined to be valid is less than a predetermined threshold.

In some embodiments, in response to determining that the previous timing advance is still valid, then, in response to a paging message, a communications device <NUM> performs an uplink transmission using the previous timing advance. The uplink transmission may be on communications resources of an uplink shared channel of the wireless access interface.

The uplink transmission may comprise a `message <NUM>' (i.e., a message which may be the third message sent in a conventional random access procedure), such as the RRC Resume Request <NUM>, transmitted at step S524 as described above.

The uplink transmission may be in accordance with further parameters configured prior to the suspension of the RRC connection. For example, the communications device <NUM> may receive, while the RRC connection is active, or as part of the suspension of the RRC connection, an indication of allocated communications resources, from which the communications resources for the uplink transmission may be selected.

In some embodiments, the allocated communications resources comprise a configured grant (CG) or 'grant free' resources. CG or grant free resources are a set of periodically repeating uplink communications resources which are semi-statically configured by the network for the use of the communications device for uplink transmission.

Preferably, the allocated communications resources are periodic having a periodicity such that the transmission of the uplink message using the allocated communications resources may occur before the transmission of the `message <NUM>' of a conventional random access procedure comprising a random access transmission on the PRACH. For example, in some embodiments, the periodicity of the allocated communications resources (i.e. the time duration between consecutive instances of the allocated communications resources) is lower than a time duration between the reception of a paging message and an earliest opportunity for a subsequent transmission of a `message <NUM>'.

It will be appreciated that in some embodiments, steps and features described herein may be combined in ways other than described above. In some embodiments, steps and features may be combined with or replace those of conventional techniques.

Thus there has been described a method of operating an infrastructure equipment of a wireless communications network, the method comprising transmitting control information via a wireless access interface provided by the wireless communications network to a communications device to configure the communications device to receive paging messages as part of a group of one or more communications devices, the communications device being configured by the control information from a first state in which the communications device monitors a pattern of paging frames of the wireless access interface for receiving paging messages determined by the communications device to a second state in which the communications device is configured to monitor the same pattern of paging frames of the wireless access interface for receiving paging messages as the group of one or more communications devices.

There has also been described communications devices and methods.

It may be noted various example approaches discussed herein may rely on information which is predetermined / predefined in the sense of being known by both the base station and the communications device. It will be appreciated such predetermined / predefined information may in general be established, for example, by definition in an operating standard for the wireless telecommunication system, or in previously exchanged signalling between the base station and communications devices, for example in system information signalling, or in association with radio resource control setup signalling, or in information stored in a SIM application. That is to say, the specific manner in which the relevant predefined information is established and shared between the various elements of the wireless telecommunications system is not of primary significance to the principles of operation described herein. It may further be noted various example approaches discussed herein rely on information which is exchanged / communicated between various elements of the wireless telecommunications system and it will be appreciated such communications may in general be made in accordance with conventional techniques, for example in terms of specific signalling protocols and the type of communication channel used, unless the context demands otherwise. That is to say, the specific manner in which the relevant information is exchanged between the various elements of the wireless telecommunications system is not of primary significance to the principles of operation described herein.

It will be appreciated that the principles described herein are not applicable only to certain types of communications device, but can be applied more generally in respect of any types of communications device, for example the approaches are not limited to machine type communication devices / IoT devices or other narrowband communications devices, but can be applied more generally, for example in respect of any type communications device operating with a wireless link to the communication network.

It will further be appreciated that the principles described herein are not applicable only to LTE-based wireless telecommunications systems, but are applicable for any type of wireless telecommunications system that supports a random access procedure comprising an exchange of random access procedure messages between a communications device and a base station.

Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. It will be appreciated that features of the dependent claims may be combined with features of the independent claims in combinations other than those explicitly set out in the claims.

Thus, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention.

Claim 1:
A method of operating an infrastructure equipment (<NUM>, <NUM>) of a wireless communications network, the method comprising:
transmitting control information (S504, S506, S508) via a wireless access interface provided by the wireless communications network to a communications device (<NUM>, <NUM>) to configure the communications device to receive paging messages (<NUM>) as part of a group of one or more communications devices, the communications device being configured by the control information from a first state in which the communications device monitors a first pattern of paging frames of the wireless access interface for receiving paging messages determined by the communications device to a second state in which the communications device is configured to monitor the same second pattern of paging frames of the wireless access interface for receiving paging messages as the group of one or more communications devices,
determining that data is to be transmitted to each of the one or more communications devices of the group and that each of the one or more communications devices has a respective radio resource control , RRC, connection which is suspended,
in response to the determining, transmitting within a paging frame of the second pattern of paging frames a paging message (<NUM>) indicating that the infrastructure equipment has data to be transmitted to each of the group of one or more communications devices; and
transmitting the data to each of the group of one or more communications devices (<NUM>, <NUM>, <NUM>).