Patent Description:
The present disclosure claims the Paris convention priority to European patent application <CIT>.

Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present invention.

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 support efficiently 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.

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) and Ultra Reliable & Low Latency Communications (URLLC) 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> <MAT>. 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.

Some services may require the transmission of small amounts of data. The transmission of small amounts of data efficiently can represent a technical challenge. Relevant background art includes "Channel Structure for Two-Step RACH" by Sony, which discusses a number of issues related to <NUM>-step and <NUM>-step RACH procedures, including MsgA PUSCH configurations in different scenarios.

Embodiments can provide flexible payload sizes, for example, for small data transmissions when a communications device is in an inactive (RRC INACTIVE) or idle (RRC IDLE) state.

<FIG>, <FIG> and <FIG> represent unclaimed aspects.

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 that 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 that 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.

As mentioned above, embodiments can provide an arrangement for transmitting small amounts of data using a RACH procedure, which may be a two step RACH procedure or a four step RACH procedure.

A more detailed illustration of two UEs/communications devices 270a, 270b is provided in <FIG>. As will be explained below, <FIG> provides an illustration of two example UEs, which may correspond to a communications device such as the communications device <NUM> of <FIG>. As shown in <FIG>, a first UE, UEa 270a performs a two step RACH procedure and a second UE, UEb 270b performs a four step RACH procedure. It will be appreciated however that two step and four-step RACH may be performed by either a conventional/legacy UE or a NR/<NUM> UE. For example a UE may fall-back to a four-step RACH if a two step RACH fails. Both UEa 270a and UEb 270b transmit signals on an uplink UL and receive signals on a downlink DL from 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>. The UEa 270a and UEb 270b are shown to transmit uplink data to the infrastructure equipment <NUM> via uplink resources UL of a wireless access interface as illustrated generally by arrows 274a, 274b to the infrastructure equipment <NUM>. The UEa 270a and the UEb 270b may similarly be configured to receive downlink data transmitted by the infrastructure equipment <NUM> via downlink resources DL as indicated by arrows 288a, 288b from the infrastructure equipment <NUM> to the UEa 270a and the UEb 270b. 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, both of the UEa 270a and the UEb 270b include a controller 290a, 290b connected to a receiver 292a, 292b which receives signals from an antenna 294a, 294b and a transmitter 296a, 296b also connected to the antenna 294a, 294b.

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 290a, 290b of the UEa 270a and the UEb 270b is configured to control the transmitter 296a, 296b and the receiver 292a, 292b 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 transmitters 296a, 296b, receivers 292a, 292b and controllers 290a, 290b 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 devices 270a, 270b 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.

The controllers <NUM>, 290a, 290b may be configured to carry out instructions which are stored on a computer readable medium, such as a non-volatile memory. The processing steps described herein may be carried out by, for example, a microprocessor in conjunction with a random access memory, operating according to instructions stored on a computer readable medium.

In wireless telecommunications networks, such as LTE type networks, there are different Radio Resource Control (RRC) modes for terminal devices. For example, it is common to support an RRC idle mode (RRC_IDLE) and an RRC connected mode (RRC_CONNECTED). A terminal device in the idle mode may transition to connected mode, for example because it needs to transmit uplink data or respond to a paging request, by undertaking a random access procedure. The random access procedure involves the terminal device transmitting a preamble on a physical random access channel and so the procedure is commonly referred to as a RACH or PRACH procedure / process.

In addition to a terminal device deciding itself to initiate a random access procedure to connect to the network, it is also possible for the network, e.g. a base station, to instruct a terminal device in connected mode to initiate a random access procedure by transmitting to the terminal device an instruction to do so. Such an instruction is sometimes referred to as a PDCCH order (Physical Downlink Control Channel order), see, for example, Section <NUM>. <NUM> in ETSI TS <NUM><NUM> V13. <NUM> (<NUM>-<NUM>) / 3GPP TS <NUM> version <NUM>. <NUM> Release <NUM> [<NUM>]. There are various scenarios in which a network triggered RACH procedure (PDCCH order) may arise.

<FIG> shows a typical RACH procedure used in LTE systems such as that described by reference to <FIG> which could also be applied to an NR wireless communications system such as that described by reference to <FIG>. A communications device (or UE) 270b, which could be in an inactive or idle mode, may have some data which it needs to send to the network. To do so, the UE sends a random access preamble <NUM> (message <NUM>) to a gNodeB <NUM>. This random access preamble <NUM> indicates the identity of the communications device <NUM> to the gNodeB <NUM>, such that the gNodeB <NUM> can address the communications device <NUM> during later stages of the RACH procedure. Assuming the random access preamble <NUM> is successfully received by the gNodeB <NUM>, the gNodeB <NUM> will transmit a random access response <NUM> message (message <NUM>) to the communications device <NUM> based on the identity indicated in the received random access preamble <NUM>. The random access response <NUM> message carries a further identity which is assigned by the gNodeB <NUM> to identify the communications device <NUM>, as well as a timing advance value such that the communications device <NUM> can change its timing to compensate for the round trip delay caused by its distance from the gNodeB <NUM> and grant uplink resources for the communications device <NUM> to transmit the data in.

Following the reception of the random access response message <NUM>, the communications device <NUM> transmits the scheduled transmission of data <NUM> to the gNodeB <NUM> (message <NUM>), using the identity assigned to it in the random access response message <NUM>. Assuming there are no collisions with other UEs, which may occur if another UE and the communications device <NUM> send the same random access preamble <NUM> to the gNodeB <NUM> at the same time and using the same frequency resources, the scheduled transmission of data <NUM> is successfully received by the gNodeB <NUM>. The gNodeB <NUM> will respond to the scheduled transmission <NUM> with a contention resolution message <NUM> (message <NUM>).

In <NUM>/NR systems, an "inactive" RRC state may be used, where a UE is able to start data transfer with a low delay in the inactive state without transition to a connected state. Various possible solutions have been proposed to permit this, one of which is a two step RACH procedure.

A development to transmit data more quickly for particular applications is known as a two step RACH [<NUM>]. As will be appreciated, compared with the four-step RACH process, the two step RACH process can provide a facility for transmitting data more quickly. Accordingly it has been proposed to develop general MAC procedures covering both physical layer and higher layer aspects for the two step RACH process. In general, the benefit of the two step RACH procedure compared with the four-step PRACH procedure is to reduce the time it takes for connection setup/resume procedure. For example in an ideal situation the two step RACH will reduce the latency by halving the number of steps from four to two for initial access UEs.

In addition, it is considered that a two step RACH procedure has potential benefits for channel access in NR unlicensed spectrum (NR-U) (see e.g. [<NUM>]).

Broadly, the two step RACH allows the combination of the transmission of the random access preamble <NUM> with the transmission of data <NUM> of <FIG> as an initial transmission ("Message A" or "MsgA"), and similarly the combination of the transmission of the random access response <NUM> and contention resolution message <NUM> as a response ("Message B", or "MsgB").

A fallback procedure may be provided to allow a RACH procedure which is started according to the specifications for a two step RACH to instead proceed according to the four-step RACH procedure. Two-step RACH may be applicable for communications devices in the RRC_INACTIVE, RRC_CONNECTED and RRC_IDLE states.

A message flow diagram illustrating the two step RACH process is shown in <FIG>. As its name suggests, in the two step RACH process, there are only two steps as follows:.

Downlink messages (i.e. messages transmitted by the base station <NUM>), such as the Message B (MsgB) or the Message <NUM>, may be preceded by a transmission of downlink control information (DCI) as a resource allocation message to indicate downlink communications resources on which the downlink message is to be transmitted.

A communications device which has recently transmitted either a Message A or a random access request may therefore monitor a downlink control channel on which the DCI may be transmitted. The communications device may determine that the DCI allocates resources for a message transmitted as part of the RACH procedure based on a temporary identity used to encode the DCI. For example, the DCI may be encoded using a random access radio network temporary identity (RA-RNTI), specifically preallocated for the purpose of encoding a DCI which allocates resources for a random access response (RAR) message.

In contrast for the transmission of uplink data, a communications device may transmit a RACH preamble in a PRACH channel and then transmit uplink information (control of data) in resources of a shared uplink channel (PUSCH) which is associated with the PRACH channel. The transmission of small amounts of uplink data in the following description can for example therefore comprises transmission of a preamble and then transmission of uplink data in associated resources of an uplink shared channel.

As mentioned above, a concept previously proposed in 3GPP for <NUM>/NR is that of small data transmission. Some examples of small data transmission and infrequent data traffic can include:.

As part of a standardisation process, 3GPP has already completed a basic version of <NUM> in Rel-<NUM> known as New Radio (NR). In addition, further enhancements have been proposed for Rel-<NUM>, incorporating new features such as two step RACH [<NUM>], Industrial Internet of Things (IIoT) [<NUM>] and NR-based Access to Unlicensed Spectrum [<NUM>].

In accordance with 3GPP current work item [<NUM>], example embodiments described below can enable small data transmission in an RRC_INACTIVE state as follows:.

Example embodiments of the present technique can provide a method of transmitting data by a communications device in a wireless communications network, the method comprising determining an amount of uplink data to be transmitted by the communications device to the wireless communications network, selecting a random access preamble from one of a plurality of groups of random access preambles, selecting modulation and coding for transmitting the uplink data, and transmitting a random access message on a wireless access interface to the wireless communications network as part of a random access procedure. The random access message includes the selected random access preamble which has been selected from one of the groups of the random access preambles. The group of the random access preambles from which the random access preamble is selected is determined according to at least one of an estimate of a transmission path loss for the communications device and the determined amount of the uplink data for transmission, and the modulation and coding for transmitting the uplink data is selected from one or more modulation and coding levels or parameters allocated for the determined group of random access preambles. According to example embodiments therefore each of the groups of random access preambles has associated with it a payload size, a path loss and or more MCS levels. According to example embodiments, each of the groups of random access preambles has associated with it a PRB set. Transmission path loss is a known expression representing a loss of signal strength with distance. It can be estimated by a communications device by known techniques.

<FIG> is a schematic diagram illustrating instructions executed by the controller <NUM> of a communications device <NUM>, which may correspond to a communications device such as the communications device <NUM> in <FIG>, in accordance with at least some of the embodiments described herein. The controller <NUM> determines an amount of uplink data to be transmitted <NUM>, estimates a path loss <NUM> of signals transmitted between the communications device <NUM> and a gNB, compares the path loss with a path loss threshold <NUM> and, on the basis of at least one of the path loss and the amount of uplink data to be transmitted, compares the determined amount of the uplink data with one or more data size thresholds <NUM>, , selects at least a random access preamble group and an MCS level <NUM>. In some examples, the communications device <NUM> may also select a PRB set in step <NUM>.

In some examples the uplink data is transmitted in or as part of a MessageA of a two-step random access procedure. In other examples the uplink data is transmitted in or as part of a Message <NUM> of a four step random access procedure. Embodiments therefore include application with the two step or the four step random access procedure which may be configured by the wireless communications network. In one embodiment, the network may provide signalling information to the communications device <NUM> indicating whether the uplink data is to be transmitted as part of a Message A of a two step random access procedure or whether the uplink data is to be transmitted as part of a Message <NUM> in a four step random access procedure. Further embodiments discussed herein are appropriate for a two step random access procedure although it will be appreciated that a four step random access procedure could be used.

In some examples, the communications device <NUM> may compare a determined amount of uplink data to one or more data thresholds which may be set by a network, such as the network <NUM> in <FIG>. The one or more data thresholds may be predetermined. <FIG> is a schematic diagram illustrating the comparison of a determined amount of uplink data <NUM> with one or more data thresholds according to one embodiment. The communications device <NUM> may compare the determined amount of the uplink data <NUM> with a data threshold Y3 <NUM> defined by the network. If the determined amount of uplink data to be transmitted <NUM> is larger than the data threshold Y3 <NUM> defined by the network then the communications device <NUM> may transition to an RRC_CONNECTED state <NUM>. If the determined amount of uplink data to be transmitted <NUM> is less than the data threshold Y3 <NUM> defined by the network then the communications device <NUM> may transition to an RRC_INACTIVE state <NUM> or may transmit uplink data whilst in the RRC_INACTIVE state <NUM>.

The communications device <NUM> may compare the determined amount of the uplink data <NUM> with a data threshold Y2 <NUM>. If the determined amount of uplink data <NUM> is less than the data threshold Y2 <NUM>, then the network may have partitioned the random access preambles into two random access preamble groups <NUM> for the communications device <NUM> in a cell, such as communications cell <NUM> in <FIG>, associated with a gNB, such as controlling node <NUM> in <FIG>, to which the communications device <NUM> is attempting to transmit uplink data. Each random access preamble group may correspond to a different payload size.

In some examples, a transmission of uplink data by the communications device <NUM> which is below the data threshold Y2 <NUM> is associated with a 3GPP Release-<NUM> two step RACH procedure and a transmission of uplink data by the communications device which is above the data threshold Y2 <NUM> but below the data threshold Y3 <NUM> is associated with a 3GPP Release-<NUM> two step RACH procedure. Thus, according to the Release-<NUM> two-step RACH procedure multiple MCS levels are provided for one or more groups of preambles and/or multiple PRB sets may be associated with the same preamble group. Alternatively more than two preamble groups are defined in Release-<NUM>. As will be appreciated, this is just one example and in other embodiments, the threshold Y2 may not be used in order to reduce the number of thresholds. Furthermore Y2 may not be configured by system information, but may be predefined.

If the network partitions the random access preambles into two groups <NUM> where each group corresponds to a different payload size as explained above, the two random access preamble groups may be random access preamble group A and random access preamble group B.

In this embodiment, the communication device <NUM> may select one of the random access preamble groups for use in an uplink data transmission procedure when the communications device <NUM> is in the RRC_INACTIVE state <NUM>. The random access preamble group A or B may have been signalled to the communications device <NUM> in a System Information Block (SIB). As will be explained below, a path loss threshold and a data threshold Y1 may be used by the communications device <NUM> to select either preamble group A or B. The data threshold Y1 may be given by, for example:.

In this embodiment, a Modulation and Coding Scheme (MCS) level and a Physical Resource Block (PRB) sets are associated respectively with each random access preamble group. The MCS levels refer to different combinations of modulation and coding parameters which may increase redundancy to improve a likelihood of data being communicated but which may reduce capacity to transmit data. The MCS level and PRB set may be signalled in the SIB for each of random access preamble Groups A and B. The payload size for each of random access preamble Groups A and B may be derived from the MCS and the number of PRBs which are signalled in the SIB for each preamble group. For example, for random access preamble group A, the SIB may signal MCS level <NUM> with PRB set <NUM> and, for random access preamble group B, the SIB may signal MCS level <NUM> with PRB set <NUM>. In this embodiment, MCS level <NUM> may have a higher modulation and/or coding rate than MCS level <NUM>.

<FIG> is a flow diagram showing a sequence of instructions which may be executed by the controller <NUM> of the communications device <NUM> when the network configures two random access preamble groups A and B. The instructions may be based on instructions <NUM>, <NUM> and <NUM> of <FIG>. As shown in <FIG>, from a start <NUM>, the communications device <NUM> proceeds to a first decision point <NUM> and compares a path loss of the uplink data to be transmitted with a path loss threshold. If the path loss of the uplink data to be transmitted is less than the path loss threshold then processing proceeds to decision step <NUM>. Otherwise processing proceeds to step <NUM> and preamble group A, MCS level <NUM> and PRB set <NUM> are selected. As will be understood from Table <NUM> below, if the path loss is greater than the path loss threshold, then the communications device <NUM> is at the cell edge and therefore will have only one data size configured. If the processing proceeds to a second decision point <NUM>, the communications device <NUM> compares the amount of the uplink data to be transmitted to a data threshold Y1 <NUM>. If the amount of the uplink data to be transmitted is less than the data threshold Y1 <NUM> then processing proceeds to step <NUM> and preamble group A, MCS level <NUM> and PRB set <NUM> are selected. Otherwise processing proceeds to step <NUM> and preamble group B, MCS level <NUM> and PRB set <NUM> are selected <NUM>.

According to this example, the communications device <NUM> is configured to select between the random access preamble groups A and B based on the conditions outlined in Table <NUM> below. The communications device <NUM> compares <NUM> the path loss of the uplink data to be transmitted from the communications device to the gNB with a path loss threshold. The communications device <NUM> compares <NUM> the determined amount of uplink data to be transmitted with a data threshold Y1 <NUM>.

Table <NUM> shows the conditions for selecting a random access preamble group by the communications device <NUM> based on the path loss threshold and the data threshold Y1 <NUM>. If the path loss of the determined amount of uplink data to be transmitted is greater than or equal to the path loss threshold and the data size of the determined amount of uplink data to be transmitted is less than or equal to the data threshold Y1 <NUM> then the communications device <NUM> may select random access preamble group A, MCS level <NUM> and PRB set <NUM><NUM>. If the path loss of the determined amount of uplink data to be transmitted is less than the path loss threshold and the data size of the determined amount of uplink data to be transmitted is less than or equal to the data threshold Y1 <NUM> then the communications device <NUM> may select random access preamble group A, MCS level <NUM> and PRB set <NUM><NUM>. If the path loss of the uplink data to be transmitted is less than the path loss threshold and the determined amount of uplink data to be transmitted is greater than the data threshold Y1 <NUM> then the communications device <NUM> may select random access preamble group B, MCS level <NUM> and PRB set <NUM><NUM>.

In the above description the uplink data for transmission may be determined from an amount of data present in an input buffer of the communications device transmitter at a predetermined time, which may be based on a radio frame of the wireless access interface.

As an illustrative example based on this embodiment, <FIG> shows a gNB <NUM> forming a cell in which a UE <NUM><NUM>, UE <NUM><NUM> and/or UE <NUM><NUM> are attached and can communicate uplink data via a wireless access interface. In particular, UE <NUM><NUM>, UE <NUM> and/or UE <NUM><NUM> may attempt to transmit uplink data to the gNB <NUM> in Message A of a two step RACH procedure. Each of UE <NUM><NUM>, UE <NUM><NUM> and UE <NUM><NUM> determines an amount of the uplink data to be transmitted <NUM>, estimates a transmission path loss <NUM> of signals transmitted between the communications device and a gNB <NUM>, compares <NUM> the transmission path loss with a path loss threshold <NUM>, compares <NUM> the determined amount of the uplink data with a data threshold Y1 <NUM>, and, on the basis of at least one of the transmission path loss and the amount of uplink data to be transmitted, selects <NUM> a random access preamble group and an MCS level. For example, UE1 <NUM> determines <NUM> that a path loss of the uplink data to be transmitted is below a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is above a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group B, MCS level <NUM> and PRB set <NUM>. UE2 <NUM> determines <NUM> that the path loss of the uplink data to be transmitted is below a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is below a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group A, MCS level <NUM> and PRB set <NUM>. UE3 <NUM> determines <NUM> that the path loss of the uplink data to be transmitted is above a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is below a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group A, MCS level <NUM> and PRB set <NUM>.

In an alternative embodiment, if the communications device <NUM> determines that the amount of uplink data to be transmitted is larger than the data threshold Y2 <NUM> and below the data threshold Y3 <NUM>, then the network may configure two random access preamble groups for the communications device <NUM> in the cell associated with the gNB, and define multiple MCS levels <NUM> for one or more of the random access preamble groups as will be explained below. In this embodiment, the uplink data to be transmitted using random access preamble group B may encounter less path loss than the uplink data to be transmitted using random access preamble group A. In this embodiment, additional MCS levels may therefore be defined for random access preamble group B. For example, the SIB for random access preamble group B may signal one of MCS levels <NUM>, <NUM> or <NUM> and PRB set <NUM>. In this embodiment, the SIB for random access preamble group A may signal MCS level <NUM> and PRB set <NUM>. In this embodiment, there are three payload sizes associated with random access preamble B corresponding to MCS levels <NUM>, <NUM> and <NUM>.

<FIG> is a flow diagram showing a sequence of instructions which may be executed by the controller <NUM> of the communications device <NUM> when the network configures two random access preamble groups A and B and defines more than one MCS level for at least one random access preamble group. The instructions may be based on instructions <NUM>, <NUM> and <NUM> of <FIG>. As shown in <FIG>, from a start <NUM>, the communications device <NUM> proceeds to a first decision point <NUM> and compares a path loss of the uplink data to be transmitted with a path loss threshold. If the path loss of the uplink data to be transmitted is less than the path loss threshold then processing proceeds to decision step <NUM>. Otherwise processing proceeds to step <NUM> and preamble group A, MCS level <NUM> and PRB set <NUM> are selected. As will be understood from Table <NUM> below, if the path loss is greater than the path loss threshold, then the communications device <NUM> is at the cell edge and therefore will have only one data size configured. If the processing proceeds to decision point <NUM>, the communications device <NUM> may compare <NUM> the amount of the uplink data to be transmitted to a data threshold Y1 <NUM>. If the amount of the uplink data to be transmitted is less than the data threshold Y1 <NUM> then processing proceeds to step <NUM> and preamble group A, MCS level <NUM> and PRB set <NUM> are selected. Otherwise processing proceeds to step <NUM> and preamble group B, one of MCS levels <NUM>, <NUM> or <NUM> and PRB set <NUM> are selected <NUM>.

Table <NUM> shows the conditions for selecting a random access preamble by the communications device <NUM> based on the path loss threshold and the data threshold Y1 <NUM>. If the path loss of the determined amount of uplink data to be transmitted is greater than or equal to the path loss threshold and the data size of the determined amount of uplink data to be transmitted is less than or equal to the data threshold Y1 <NUM> then the communications device <NUM> may select random access preamble group A, MCS level <NUM> and PRB set <NUM><NUM>. If the path loss of the determined amount of uplink data to be transmitted is less than the path loss threshold and the data size of the determined amount of uplink data to be transmitted is less than or equal to the data threshold Y1 <NUM> then the communications device <NUM> may select random access preamble group A, MCS level <NUM> and PRB set <NUM><NUM>. If the path loss of the uplink data to be transmitted is less than the path loss threshold and the determined amount of uplink data to be transmitted is greater than the data threshold Y1 <NUM> then the communications device <NUM> may select random access preamble group B, one of MCS levels <NUM>, <NUM> or <NUM> and PRB set <NUM><NUM>. In this example embodiment, the communications device <NUM> selects one of MCS levels <NUM>, <NUM> or <NUM> according to at least one of the determined amount of uplink data to be transmitted and the condition of the radio channel used to transmit the uplink data.

As an illustrative example based on this embodiment, <FIG> shows a gNB <NUM> forming a cell in which a UE <NUM><NUM>, UE <NUM><NUM> and/or UE <NUM><NUM> are attached and can communicate uplink data via a wireless access interface. In particular, UE <NUM><NUM>, UE <NUM> and/or UE <NUM><NUM> may attempt to transmit uplink data to the gNB <NUM> in Message A of a two step RACH procedure. Each of UE <NUM><NUM>, UE <NUM><NUM> and UE <NUM><NUM> determines an amount of the uplink data to be transmitted <NUM>, estimates <NUM> a transmission path loss of signals transmitted between the communications device and a gNB <NUM>, compares <NUM> the transmission path loss with a path loss threshold <NUM>, compares <NUM> the determined amount of the uplink data with a data threshold Y1 <NUM>, and, on the basis of at least one of a transmission path loss and the amount of uplink data to be transmitted, selects a random access preamble group and an MCS level <NUM>. For example, UE1 <NUM> determines <NUM> that a path loss of the uplink data to be transmitted is below a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is above a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group B, one of MCS levels <NUM>, <NUM> or <NUM> and PRB set <NUM>. UE2 <NUM> determines <NUM> that the path loss of the uplink data to be transmitted is below a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is below a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group A, MCS level <NUM> and PRB set <NUM>. UE3 <NUM> determines <NUM> that the path loss of the uplink data to be transmitted is above a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is below a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group A, MCS level <NUM> and PRB set <NUM>.

In this embodiment, the gNB may attempt to determine the payload associated with the selected random access preamble by blindly decoding the uplink data transmitted to the gNB by the communications device by, for example, first attempting to decode the data using MCS level <NUM>. If this fails, the gNB may attempt to decode the uplink data using MCS3. If this fails, the gNB may attempt to decode the uplink data using MCS4. It will be appreciated that the order in which the eNB attempts to use MCS levels to blindly decode the small data transmitted can be changed.

In an alternative embodiment, as shown in <FIG>, if the communications device <NUM> determines that an amount of uplink data to be transmitted <NUM> is above a data threshold Y2 <NUM> and below a data threshold Y3 <NUM> then the network may configure more than two random access preamble groups <NUM> for the communications device <NUM> in the cell associated with the gNB. <FIG> is broadly based on <FIG>, with the exception that in a case where the amount of the uplink data <NUM> to be transmitted is between the data threshold Y2 <NUM> and data threshold Y3 <NUM>, it may be possible to perform further preamble grouping <NUM>. In this embodiment, for example when the path loss of the uplink data is small, further preamble grouping is possible and a different PRB set for each group can be supported. For example, if the path loss of the uplink data to be transmitted is less than the path loss threshold and the determined amount of uplink data to be transmitted <NUM> is greater than the data threshold Y1 <NUM>, then the communications device <NUM> may select random access preamble group B, C or D. The preamble groups may be communicated by the network in SIB. For random access preamble group B, MCS level <NUM> and PRB set <NUM> may be defined, for random access preamble group C, MCS level <NUM> and PRB set <NUM> may be defined. For random access preamble group D, MCS level <NUM> and PRB set <NUM> may be defined. The random access preamble groups A, B, C and D may each correspond to a different payload size.

<FIG> is a flow diagram showing a sequence of instructions which may be executed by the controller <NUM> of the communications device <NUM> when the network configures more than two random access preamble groups. The instructions may be based on instructions <NUM>, <NUM> and <NUM> of <FIG>. As shown in <FIG>, from a start <NUM>, the communications device <NUM> proceeds to a first decision point <NUM> and compares a path loss of the uplink data to be transmitted with a path loss threshold. If the path loss of the uplink data to be transmitted is less than the threshold then processing proceeds to decision step <NUM>. Otherwise processing proceeds to step <NUM> and preamble group A, MCS level <NUM> and PRB set <NUM> are selected. As will be understood from Table <NUM> below, if the path loss is greater than the path loss threshold, then the communications device <NUM> is at the cell edge and therefore will have only one data size configured. If the processing proceeds to decision point <NUM>, the communications device <NUM> may compare <NUM> the amount of the uplink data to be transmitted to a data threshold Y1 <NUM>. If the amount of the uplink data to be transmitted is less than the data threshold Y1 <NUM> then processing proceeds to step <NUM> and preamble group A, MCS level <NUM> and PRB set <NUM> are selected. Otherwise processing proceeds to step <NUM> selects either preamble group B, MCS level <NUM> and PRB set <NUM> or preamble group C, MCS level <NUM> and PRB set <NUM> or preamble group D, MCS level <NUM> and PRB <NUM>.

Table <NUM> shows the conditions for selecting a random access preamble by the communications device <NUM> based on the path loss threshold and the data threshold Y1 <NUM>. If the path loss of the determined amount of uplink data to be transmitted is greater than or equal to the path loss threshold and the data size of the determined amount of uplink data to be transmitted is less than or equal to the data threshold Y1 <NUM> then the communications device <NUM> may select random access preamble group A, MCS level <NUM> and PRB set <NUM><NUM>. If the path loss of the determined amount of uplink data to be transmitted is less than the path loss threshold and the data size of the determined amount of uplink data to be transmitted is less than or equal to the data threshold Y1 <NUM> then the communications device <NUM> may select random access preamble group A, MCS level <NUM> and PRB set <NUM><NUM>. If the path loss of the uplink data to be transmitted is less than the path loss threshold and the determined amount of uplink data to be transmitted is greater than the data threshold Y1 <NUM> then the communications device <NUM> selects <NUM> either preamble group B, MCS level <NUM> and PRB set <NUM> or preamble group C, MCS <NUM> and PRB set <NUM> or preamble group D, MCS level <NUM> and PRB <NUM>.

As an illustrative example based on this embodiment, <FIG> shows a gNB <NUM> forming a cell in which a UE <NUM><NUM>, UE <NUM><NUM> and/or UE <NUM><NUM> are attached and can communicate uplink data via a wireless access interface. In particular, UE <NUM><NUM>, UE <NUM> and/or UE <NUM><NUM> may attempt to transmit uplink data to the gNB <NUM> in Message A of a two step RACH procedure. Each of UE <NUM><NUM>, UE <NUM><NUM> and UE <NUM><NUM> determines an amount of the uplink data to be transmitted <NUM>, estimates <NUM> a transmission path loss of signals transmitted between the communications device and a gNB <NUM>, compares <NUM> the transmission path loss with a path loss threshold <NUM>, compares <NUM> the determined amount of the uplink data with a data threshold Y1 <NUM>, and, on the basis of at least one of a transmission path loss and the amount of uplink data to be transmitted, selects a random access preamble group and an MCS level <NUM>. For example, UE1 <NUM> determines <NUM> that a path loss of the uplink data to be transmitted is below a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is above a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group B, MCS level <NUM> and PRB set <NUM>. UE2 <NUM> determines <NUM> that the path loss of the uplink data to be transmitted is below a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is above a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group C, MCS level <NUM> and PRB set <NUM>. UE3 <NUM> determines <NUM> that the path loss of the uplink data to be transmitted is above a path loss threshold <NUM> and determines <NUM> that the amount of the uplink data to be transmitted is below a data threshold Y1 <NUM>, and therefore selects <NUM> preamble group A, MCS level <NUM> and PRB set <NUM>. It will be appreciated that either of UE <NUM><NUM> or UE <NUM><NUM> could have been configured to choose preamble group D, MCS level <NUM> and PRB set <NUM>.

In an alternative embodiment, if it is determined that the determined amount of the uplink data is above a data threshold Y2 <NUM>, <NUM> and below a data threshold Y3 <NUM>, <NUM> a procedure may be employed involving an uplink data transmission on pre-configured PUSCH (Physical Uplink Shared Channel) resources. In this embodiment, a number of PRBs and one or more MCS levels may be pre-defined. In this example embodiment, the communications device <NUM> selects an MCS level according to at least one of the determined amount of uplink data to be transmitted and the condition of the radio channel used to transmit the uplink data.

In any of the above example embodiments, if the communications device <NUM> detects that the data to be transmitted is larger than the data threshold Y3 defined by the network <NUM>, <NUM>, the communications device <NUM> may connect to the network and transmit data in the RRC_CONNECTED state <NUM>, <NUM>. The communications device <NUM> may detect that the uplink data to be transmitted is larger than the data threshold Y3 <NUM>, <NUM> defined by the network. This data threshold Y3 <NUM>, <NUM> may be predefined. In this embodiment, the communications device <NUM> may transmit a buffer status report (BSR). In some embodiments, the communications device <NUM> may provide a BSR with an exaggerated buffer level so that the network allows the communications device <NUM> to move into the RRC_CONNECTED state to transmit data.

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 URLLC / IIoT devices or other low latency communications devices, but can be applied more generally, for example in respect of any type of communications device operating with a wireless link to the communication network.

Claim 1:
A method of transmitting data by a communications device (<NUM>, <NUM>) in a wireless communications network (<NUM>), the method comprising
determining (<NUM>) an amount of uplink data to be transmitted by the communications device to the wireless communications network, and either
transitioning (<NUM>) to a connected state if the determined amount of the uplink data is greater than a first threshold (Y3) or, if the determined amount of the uplink data is less than the first threshold (Y3),
selecting (<NUM>) a random access preamble from one of a plurality of groups of random access preambles,
selecting (<NUM>) modulation and coding for transmitting the uplink data, and
transmitting a random access message (<NUM>, <NUM>) on a wireless access interface to the wireless communications network as part of a random access procedure, the random access message including the selected random access preamble from one of the plurality of groups of the random access preambles, wherein the group of the random access preambles from which the random access preamble is selected is determined according to at least one of an estimate (<NUM>) of a transmission path loss for the communications device and the determined amount of the uplink data for transmission and each of the groups of the random access preambles has a plurality of modulating and coding scheme levels associated with it, and the modulation and coding for transmitting the uplink data is selected from one or more modulation and coding scheme levels allocated for the determined group of random access preambles, at least two of the modulation and coding scheme levels correspond to a different payload size, and the selecting the modulation and coding scheme level includes selecting one of the plurality of modulation and coding scheme levels associated with the selected one of the group of random access preambles.