WO2023052220A1

WO2023052220A1 - Method, apparatus and computer program

Info

Publication number: WO2023052220A1
Application number: PCT/EP2022/076239
Authority: WO
Inventors: Subramanya CHANDRASHEKAR; Philippe Godin; Daniela Laselva
Original assignee: Nokia Technologies Oy
Priority date: 2021-10-01
Filing date: 2022-09-21
Publication date: 2023-04-06

Abstract

There is provided an apparatus comprising means configured to perform: receiving, at a distributed unit of a network node from a user equipment, a small data transmission in a cell; in response to receiving the small data transmission, determining to generate a configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; generating the configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; receiving, from the centralised unit of the network node, an activation indication for the configured grant- small data transmission configuration for the user equipment; and in response to receiving the activation indication, reserving resources associated with the configured grant-small data transmission configuration for a subsequent small data transmission.

Description

METHOD, APPARATUS AND COMPUTER PROGRAM

Field

The present application relates to a method, apparatus, and computer program for a wireless communication system.

Background

A communication system may be a facility that enables communication sessions between two or more entities such as user terminals, base stations/access points and/or other nodes by providing carriers between the various entities involved in the communications path. A communication system may be provided, for example, by means of a communication network and one or more compatible communication devices. The communication sessions may comprise, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and/or content data and so on. Non-limiting examples of services provided comprise two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet.

Summary

According to an aspect, there is provided an apparatus comprising means configured to perform: receiving, at a distributed unit of a network node from a user equipment, a small data transmission in a cell; in response to receiving the small data transmission, determining to generate a configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; generating the configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and in response to receiving the activation indication, reserving resources associated with the configured grant-small data transmission configuration for a subsequent small data transmission. In an example, the request is comprised in a message. In an example, the request is an indication included in a random access channel SDT request.

In an example, the user equipment is in RRC inactive mode.

In an example, in response to receiving the activation indication, providing an RRC release message and the configured grant-small data transmission configuration to the user equipment.

In an example, the small data transmission comprises a request of the user equipment to receive a configured grant-small data transmission configuration, and wherein the determining to generate the configured grant-small data transmission configuration is based on the received request from the user equipment.

In an example, the determining to generate the configured grant-small data transmission configuration is based on at least one of: a stored indication associated with a: type of the user equipment, and/or a type of data radio bearer, and/or a type of signalling radio bearer, which is involved in the small data transmission; an indication stored in a context associated with the user equipment involved in the small data transmission; an indication stored in a context associated with one of: the data radio bearer and/or the signalling radio bearer involved in small data transmission.

In an example, the small data transmission comprises a radio resource control message, which is provided to the centralised unit of the network node with the configured grant-small data transmission configuration.

In an example, the radio resource control message is: a radio resource control resume request, or a radio resource control message which is related to small data transmission.

In an example, the small data transmission comprises an inactive-radio network temporary identifier of the user equipment.

In an example, the configured grant-small data transmission configuration for the user equipment is generated using the l-RNTI of the user equipment comprised in the request.

In an example, the means are configured to perform, before receiving the small data transmission: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode; and in response to providing the indication, storing a context of the user equipment in the distributed unit of the network node. In an example, the context of the user equipment is stored in the distributed unit based on a predefined criteria, wherein the predefined criteria comprises at least one of: user equipment assistance information, a type of the user equipment, and a mobility history of the user equipment.

In an example, the means configurated to perform the generating the configured grant-small data transmission configuration comprises: identifying, at the distributed unit of the network node, that there is a stored context of the user equipment using the received inactive-radio network temporary identifier; retrieving the stored context of the user equipment; and using the context of the user equipment to generate the configured grant-small data transmission configuration in the cell.

In an example, the context of the user equipment comprises at least one of: data radio bearers eligible for small data transmission, and a data payload size for each of the data radio bearers.

In an example, the small data transmission comprises a data payload comprising a logical channel identifier, wherein the means configured to perform the generating the configured grant-small data transmission configuration comprises: using the logical channel identifier to generate the configured grant-small data transmission configuration.

In an example, the means are configured to perform: identifying at least one of: a type of the user equipment, a type of data radio bearer, and a type of signalling radio bearer, requested by the user equipment using one or more bits of the inactive-radio network temporary identifier of the user equipment comprised in the small data transmission; and generating the configured grant-small data transmission configuration for the user equipment based on the at least one of: the type of the user equipment, the type of data radio bearer, and the type of signalling radio bearer.

In an example, the means configured to perform the generating of the configured grant-small data transmission configuration is based on small data transmission context information, received in a message from the centralised unit, for each of the at least one of: the type of the user equipment, the type of data radio bearer, and the type of signalling radio bearer.

In an example, the means are configured to perform, before receiving the small data transmission: receiving, from the centralised unit of the network node, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises an associated payload size for data transmissions.

In an example, the means configurated to perform the generating the configured grant-small data transmission configuration comprises: selecting a data radio bearer from the set of one or more data radio bearers based on the received message; and generating the configured grant-small data transmission configuration using the selected data radio bearer and associated payload size.

In an example, the set of one or more data radio bearers are received at a time of a data radio bearer setup procedure using one of: a user equipment context setup, and a user equipment modification procedure.

In an example, the user equipment context setup is an F1 user equipment context setup, and/or the modification procedure is an F1 modification procedure.

In an example, the configured grant-small data transmission configuration for the user equipment is different to a previous configured grant-small data transmission configuration used by the user equipment when connected to a last serving cell.

In an example, the apparatus is for the distributed unit of the network node.

According to an aspect, there is provided an apparatus comprising: one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: receiving, at a distributed unit of a network node from a user equipment, a small data transmission in a cell; in response to receiving the small data transmission, determining to generate a configured grantsmall data transmission configuration for the cell for the user equipment based on the received small data transmission; generating the configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and in response to receiving the activation indication, reserving resources associated with the configured grant-small data transmission configuration for a subsequent small data transmission.

In an example, the request is comprised in a message. In an example, the request is an indication included in a random access channel SDT request.

In an example, the user equipment is in RRC inactive mode. In an example, in response to receiving the activation indication, providing an RRC release message and the configured grant-small data transmission configuration to the user equipment.

In an example, the apparatus is caused to perform, before receiving the small data transmission: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode; and in response to providing the indication, storing a context of the user equipment in the distributed unit of the network node.

In an example, the context of the user equipment is stored in the distributed unit based on a predefined criteria, wherein the predefined criteria comprises at least one of: user equipment assistance information, a type of the user equipment, and a mobility history of the user equipment. In an example, the apparatus being caused to perform the generating the configured grant-small data transmission configuration comprises: identifying, at the distributed unit of the network node, that there is a stored context of the user equipment using the received inactive-radio network temporary identifier; retrieving the stored context of the user equipment; and using the context of the user equipment to generate the configured grant-small data transmission configuration in the cell.

In an example, the apparatus is caused to perform: identifying at least one of: a type of the user equipment, a type of data radio bearer, and a type of signalling radio bearer, requested by the user equipment using one or more bits of the inactive-radio network temporary identifier of the user equipment comprised in the small data transmission; and generating the configured grant-small data transmission configuration for the user equipment based on the at least one of: the type of the user equipment, the type of data radio bearer, and the type of signalling radio bearer.

In an example, the apparatus being caused to perform the generating of the configured grant-small data transmission configuration is based on small data transmission context information, received in a message from the centralised unit, for each of the at least one of: the type of the user equipment, the type of data radio bearer, and the type of signalling radio bearer.

In an example, the apparatus is caused to perform, before receiving the small data transmission: receiving, from the centralised unit of the network node, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises an associated payload size for data transmissions.

In an example, the apparatus being caused to perform the generating the configured grant-small data transmission configuration comprises: selecting a data radio bearer from the set of one or more data radio bearers based on the received message; and generating the configured grant-small data transmission configuration using the selected data radio bearer and associated payload size.

In an example, the apparatus is for the distributed unit of the network node.

According to an aspect, there is provided a method comprising: receiving, at a distributed unit of a network node from a user equipment, a small data transmission in a cell; in response to receiving the small data transmission, determining to generate a configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; generating the configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; receiving, from the centralised unit of the network node, an activation indication for the configured grantsmall data transmission configuration for the user equipment; and in response to receiving the activation indication, reserving resources associated with the configured grant-small data transmission configuration for a subsequent small data transmission.

In an example, the user equipment is in RRC inactive mode.

In an example, the small data transmission comprises a request of the user equipment to receive a configured grant-small data transmission configuration, and wherein the determining to generate the configured grant-small data transmission configuration is based on the received request from the user equipment. In an example, the determining to generate the configured grant-small data transmission configuration is based on at least one of: a stored indication associated with a: type of the user equipment, and/or a type of data radio bearer, and/or a type of signalling radio bearer, which is involved in the small data transmission; an indication stored in a context associated with the user equipment involved in the small data transmission; an indication stored in a context associated with one of: the data radio bearer and/or the signalling radio bearer involved in small data transmission.

In an example, the method comprises, before receiving the small data transmission: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode; and in response to providing the indication, storing a context of the user equipment in the distributed unit of the network node.

In an example, the context of the user equipment is stored in the distributed unit based on a predefined criteria, wherein the predefined criteria comprises at least one of: user equipment assistance information, a type of the user equipment, and a mobility history of the user equipment.

In an example, the generating the configured grant-small data transmission configuration comprises: identifying, at the distributed unit of the network node, that there is a stored context of the user equipment using the received inactive-radio network temporary identifier; retrieving the stored context of the user equipment; and using the context of the user equipment to generate the configured grant-small data transmission configuration in the cell. In an example, the context of the user equipment comprises at least one of: data radio bearers eligible for small data transmission, and a data payload size for each of the data radio bearers.

In an example, the method comprises: identifying at least one of: a type of the user equipment, a type of data radio bearer, and a type of signalling radio bearer, requested by the user equipment using one or more bits of the inactive-radio network temporary identifier of the user equipment comprised in the small data transmission; and generating the configured grant-small data transmission configuration for the user equipment based on the at least one of: the type of the user equipment, the type of data radio bearer, and the type of signalling radio bearer.

In an example, the generating of the configured grant-small data transmission configuration is based on small data transmission context information, received in a message from the centralised unit, for each of the at least one of: the type of the user equipment, the type of data radio bearer, and the type of signalling radio bearer.

In an example, the method comprises, before receiving the small data transmission: receiving, from the centralised unit of the network node, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises an associated payload size for data transmissions.

In an example, the generating the configured grant-small data transmission configuration comprises: selecting a data radio bearer from the set of one or more data radio bearers based on the received message; and generating the configured grantsmall data transmission configuration using the selected data radio bearer and associated payload size.

In an example, the user equipment context setup is an F1 user equipment context setup, and/or the modification procedure is an F1 modification procedure. In an example, the configured grant-small data transmission configuration for the user equipment is different to a previous configured grant-small data transmission configuration used by the user equipment when connected to a last serving cell.

In an example, the method is performed by the distributed unit of the network node.

According to an aspect, there is provided an apparatus comprising means configured to perform: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration for a user equipment generated by the distributed unit of the network node, wherein the configured grantsmall data transmission configuration is received within a message comprising a radio resource control message; determining to activate the configured grant-small data transmission configuration for the user equipment; providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and providing a radio resource control release message to the user equipment including the configured grant-small data transmission configuration when the activation indication is provided to the distributed unit.

In an example, the means are configured to perform, before receiving the configured grant-small data transmission configuration: providing, to the distributed unit, at least one of: an indication to keep the user equipment context when moving the user equipment to radio resource control inactive mode; an indication to keep the user equipment context when moving the user equipment to radio resource control inactive mode together with an indication to generate a configured grant-small data transmission configuration at a subsequent small data transmission; a set of one or more data radio bearers and/or signalling radio bearers that are eligible for small data transmissions, wherein each data radio bearer and/or signalling radio bearers in the set comprises at least an associated payload size for data transmissions; and a set of data radio bearer types and/or signalling radio bearers types or user equipment types that are eligible for generating a configured grant configuration at next small data transmission.

In an example, the set of one or more data radio bearers and/or signalling radio bearers are provided at a time of a data radio bearer and/or signalling radio bearer setup procedure using one of: a user equipment context setup, and a user equipment modification procedure. In an example, the means are configured to perform: providing, as part of a non-user equipment associated message to the distributed unit, a set of small data transmission context pieces of information associated with a data radio bearer type and/or a signalling radio bearer type and/or a user equipment type to be used when generating a configured grant configuration.

According to an aspect, there is provided an apparatus comprising: one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration for a user equipment generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is received within a message comprising a radio resource control message; determining to activate the configured grant-small data transmission configuration for the user equipment; providing, to the distributed unit of the network node, an activation indication for the configured grantsmall data transmission configuration for the user equipment; and providing a radio resource control release message to the user equipment including the configured grant-small data transmission configuration when the activation indication is provided to the distributed unit.

In an example, the apparatus is caused to perform, before receiving the configured grant-small data transmission configuration: providing, to the distributed unit, at least one of: an indication to keep the user equipment context when moving the user equipment to radio resource control inactive mode; an indication to keep the user equipment context when moving the user equipment to radio resource control inactive mode together with an indication to generate a configured grant-small data transmission configuration at a subsequent small data transmission; a set of one or more data radio bearers and/or signalling radio bearers that are eligible for small data transmissions, wherein each data radio bearer and/or signalling radio bearers in the set comprises at least an associated payload size for data transmissions; and a set of data radio bearer types and/or signalling radio bearers types or user equipment types that are eligible for generating a configured grant configuration at next small data transmission.

In an example, the set of one or more data radio bearers and/or signalling radio bearers are provided at a time of a data radio bearer and/or signalling radio bearer setup procedure using one of: a user equipment context setup, and a user equipment modification procedure.

In an example, the apparatus is caused to perform: providing, as part of a nonuser equipment associated message to the distributed unit, a set of small data transmission context pieces of information associated with a data radio bearer type and/or a signalling radio bearer type and/or a user equipment type to be used when generating a configured grant configuration.

According to an aspect, there is provided a method comprising: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration for a user equipment generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is received within a message comprising a radio resource control message; determining to activate the configured grant-small data transmission configuration for the user equipment; providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and providing a radio resource control release message to the user equipment including the configured grant-small data transmission configuration when the activation indication is provided to the distributed unit.

In an example, the method comprises, before receiving the configured grantsmall data transmission configuration: providing, to the distributed unit, at least one of: an indication to keep the user equipment context when moving the user equipment to radio resource control inactive mode; an indication to keep the user equipment context when moving the user equipment to radio resource control inactive mode together with an indication to generate a configured grant-small data transmission configuration at a subsequent small data transmission; a set of one or more data radio bearers and/or signalling radio bearers that are eligible for small data transmissions, wherein each data radio bearer and/or signalling radio bearers in the set comprises at least an associated payload size for data transmissions; and a set of data radio bearer types and/or signalling radio bearers types or user equipment types that are eligible for generating a configured grant configuration at next small data transmission.

In an example, the set of one or more data radio bearers and/or signalling radio bearers are provided at a time of a data radio bearer and/or signalling radio bearer setup procedure using one of: a user equipment context setup, and a user equipment modification procedure. In an example, the method comprises: providing, as part of a non-user equipment associated message to the distributed unit, a set of small data transmission context pieces of information associated with a data radio bearer type and/or a signalling radio bearer type and/or a user equipment type to be used when generating a configured grant configuration.

According to an aspect, there is provided an apparatus comprising means configured to perform: providing, to a distributed unit of a network node within a small data transmission, a request for a configured grant small data transmission configuration for a serving cell; and receiving, from a centralised unit of the network node, a configured grant-small data transmission configuration to be used by a user equipment in the serving cell.

In an example, the request is indicated in a random access channel.

In an example, the request is comprised in a message terminated in the distributed unit of the network node.

In an example, the means are configured to perform: providing, to the distributed unit of the network node, within the small data transmission a radio resource control message together with the request to receive configured grant resources for small data transmissions in a cell.

In an example, the radio resource control message is a radio resource control resume request message.

In an example, the means are configured to perform: receiving, from the centralised unit of the network node, a radio resource control release message with the configured grant-small data transmission configuration for the user equipment.

In an example, the user equipment is in radio resource control inactive mode.

In an example, the apparatus is for the user equipment.

According to an aspect, there is provided an apparatus comprising: one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: providing, to a distributed unit of a network node within a small data transmission, a request for a configured grant small data transmission configuration for a serving cell; and receiving, from a centralised unit of the network node, a configured grant-small data transmission configuration to be used by a user equipment in the serving cell. In an example, the request is indicated in a random access channel.

In an example, the apparatus is caused to perform: providing, to the distributed unit of the network node, within the small data transmission a radio resource control message together with the request to receive configured grant resources for small data transmissions in a cell.

In an example, the apparatus is caused to perform: receiving, from the centralised unit of the network node, a radio resource control release message with the configured grant-small data transmission configuration for the user equipment.

In an example, the user equipment is in radio resource control inactive mode.

In an example, the apparatus is for the user equipment.

According to an aspect, there is provided a method comprising: providing, to a distributed unit of a network node within a small data transmission, a request for a configured grant small data transmission configuration for a serving cell; and receiving, from a centralised unit of the network node, a configured grant-small data transmission configuration to be used by a user equipment in the serving cell.

In an example, the request is indicated in a random access channel.

In an example, the method comprises: providing, to the distributed unit of the network node, within the small data transmission a radio resource control message together with the request to receive configured grant resources for small data transmissions in a cell.

In an example, the method comprises: receiving, from the centralised unit of the network node, a radio resource control release message with the configured grantsmall data transmission configuration for the user equipment. In an example, the small data transmission comprises an inactive-radio network temporary identifier of the user equipment.

In an example, the user equipment is in radio resource control inactive mode.

In an example, the method is performed by the user equipment.

According to an aspect, there is provided a computer program comprising computer executable instructions which when run on one or more processors perform: receiving, at a distributed unit of a network node from a user equipment, a small data transmission in a cell; in response to receiving the small data transmission, determining to generate a configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; generating the configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and in response to receiving the activation indication, reserving resources associated with the configured grant-small data transmission configuration for a subsequent small data transmission.

According to an aspect, there is provided a computer program comprising computer executable instructions which when run on one or more processors perform: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration for a user equipment generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is received within a message comprising a radio resource control message; determining to activate the configured grant-small data transmission configuration for the user equipment; providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and providing a radio resource control release message to the user equipment including the configured grant-small data transmission configuration when the activation indication is provided to the distributed unit.

According to an aspect, there is provided a computer program comprising computer executable instructions which when run on one or more processors perform: providing, to a distributed unit of a network node within a small data transmission, a request for a configured grant small data transmission configuration for a serving cell; and receiving, from a centralised unit of the network node, a configured grant-small data transmission configuration to be used by a user equipment in the serving cell.

According to an aspect, there is provided an apparatus comprising means configured to perform: receiving, at a distributed unit of a network node from a user equipment, a request to receive configured grant resources for small data transmissions in a cell; in response to receiving the request, generating a configured grant-small data transmission configuration for the user equipment based on the received request; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; and receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment.

In an example, the user equipment is in RRC inactive mode.

In an example, the request comprises an inactive-radio network temporary identifier of the user equipment.

In an example, the means are configured to perform, before receiving the request: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode; and in response to providing the indication, storing a context of the user equipment in the distributed unit of the network node.

In an example, the means configurated to perform the generating the configured grant-small data transmission configuration comprises: identifying, at the distributed unit of the network node, that the user equipment has performed an intradistributed unit cell change; retrieving the stored context of the user equipment; and using the context of the user equipment to generate the configured grant-small data transmission configuration in the cell requested by the user equipment.

In an example, the request comprises a data payload comprising a logical channel identifier, wherein the means configured to perform the generating the configured grant-small data transmission configuration comprises: using the logical channel identifier to generate the configured grant-small data transmission configuration.

In an example, the means are configured to perform: identifying a type of the user equipment using one or more bits of the inactive-radio network temporary identifier of the user equipment comprised in the request; and generating the configured grant-small data transmission configuration for the user equipment based on the type of the user equipment.

In an example, the means are configured to perform, before receiving the request: receiving, from the centralised unit of the network node, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises an associated payload size for data transmissions.

In an example, the set of one or more data radio bearers are received at a time of a data radio bearer setup procedure using one of: a user equipment context setup, and a modification procedure.

In an example, the user equipment context setup is an F1 user equipment context setup, and/or the modification procedure is an F1 modification procedure

In an example, the configured grant-small data transmission configuration for the user equipment is different to a previous configured grant-small data transmission configuration used by the UE when connected to a last serving cell.

In an example, the request for resources for small data transmissions is comprised within a radio resource control resume request. In an example, the apparatus is for a target cell.

In an example, the apparatus is for the distributed unit of the network node.

According to another aspect, there is provided an apparatus comprising means configured to perform: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is for a user equipment; and providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment.

In an example, the means are configured to perform: providing a radio resource control release message and the configured grant-small data transmission configuration to the user equipment.

In an example, the means are configured to perform, before receiving the configured grant-small data transmission configuration: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode.

In an example, the means are configured to perform, before receiving the request: providing, to the distributed unit, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises at least an associated payload size for data transmissions.

In an example, the set of one or more data radio bearers are provided at a time of a data radio bearer setup procedure using one of: a user equipment context setup, and a modification procedure.

According to another aspect, there is provided an apparatus comprising means configured to perform: providing, to a distributed unit of a network node, a request to receive configured grant resources for small data transmissions in a cell; and receiving, from a centralised unit of the network node, an activation indication for a configured grant-small data transmission configuration for a user equipment.

In an example, the request is included as an indicator in a random access channel-based small data transmission procedure.

In an example, the request is comprised in a message provided to the distributed unit of the network node. In an example, the means are configured to perform: providing, to the distributed unit of the network node, a radio resource control resume request with the request to receive configured grant resources for small data transmissions in a cell.

In an example, the user equipment is in radio resource control inactive mode.

In an example, the apparatus is for the user equipment.

According to another aspect, there is provided a method comprising: receiving, at a distributed unit of a network node from a user equipment, a request to receive configured grant resources for small data transmissions in a cell; in response to receiving the request, generating a configured grant-small data transmission configuration for the user equipment based on the received request; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; and receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment.

In an example, the user equipment is in RRC inactive mode.

In an example, the method comprises, before receiving the request: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode; and in response to providing the indication, storing a context of the user equipment in the distributed unit of the network node. In an example, the context of the user equipment is stored in the distributed unit based on a predefined criteria, wherein the predefined criteria comprises at least one of: user equipment assistance information, a type of the user equipment, and a mobility history of the user equipment.

In an example, the generating the configured grant-small data transmission configuration comprises: identifying, at the distributed unit of the network node, that the user equipment has performed an intra-distributed unit cell change; retrieving the stored context of the user equipment; and using the context of the user equipment to generate the configured grant-small data transmission configuration in the cell requested by the user equipment.

In an example, the request comprises a data payload comprising a logical channel identifier, wherein the generating the configured grant-small data transmission configuration comprises: using the logical channel identifier to generate the configured grant-small data transmission configuration.

In an example, the method comprises: identifying a type of the user equipment using one or more bits of the inactive-radio network temporary identifier of the user equipment comprised in the request; and generating the configured grant-small data transmission configuration for the user equipment based on the type of the user equipment.

In an example, the method comprises, before receiving the request: receiving, from the centralised unit of the network node, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises an associated payload size for data transmissions.

In an example, the set of one or more data radio bearers are received at a time of a data radio bearer setup procedure using one of: a user equipment context setup, and a modification procedure. In an example, the user equipment context setup is an F1 user equipment context setup, and/or the modification procedure is an F1 modification procedure

In an example, the request for resources for small data transmissions is comprised within a radio resource control resume request.

In an example, the distributed unit is for a target cell.

According to another aspect, there is provided a method comprising: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is for a user equipment; and providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment.

In an example, the method comprises: providing a radio resource control release message and the configured grant-small data transmission configuration to the user equipment.

In an example, the method comprises, before receiving the configured grantsmall data transmission configuration: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode.

In an example, the method comprises, before receiving the request: providing, to the distributed unit, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises at least an associated payload size for data transmissions.

In an example, the method is performed by a centralised unit of the network node.

According to another aspect, there is provided a method comprising: providing, to a distributed unit of a network node, a request to receive configured grant resources for small data transmissions in a cell; and receiving, from a centralised unit of the network node, an activation indication for a configured grant-small data transmission configuration for a user equipment.

In an example, the request is comprised in a message provided to the distributed unit of the network node.

In an example, the method comprises: providing, to the distributed unit of the network node, a radio resource control resume request with the request to receive configured grant resources for small data transmissions in a cell.

In an example, the method comprises: receiving, from the centralised unit of the network node, a radio resource control release message with the configured grantsmall data transmission configuration for the user equipment.

In an example, the user equipment is in radio resource control inactive mode.

In an example, the method is performed by the user equipment.

According to an aspect, there is provided a computer program comprising computer executable instructions which when run on one or more processors perform: receiving, at a distributed unit of a network node from a user equipment, a request to receive configured grant resources for small data transmissions in a cell; in response to receiving the request, generating a configured grant-small data transmission configuration for the user equipment based on the received request; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; and receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment.

According to an aspect, there is provided a computer program comprising computer executable instructions which when run on one or more processors perform: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is for a user equipment; and providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment. According to an aspect, there is provided a computer program comprising computer executable instructions which when run on one or more processors perform: providing, to a distributed unit of a network node, a request to receive configured grant resources for small data transmissions in a cell; and receiving, from a centralised unit of the network node, an activation indication for a configured grant-small data transmission configuration for a user equipment.

According to an aspect, there is provided an apparatus comprising: one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: receiving, at a distributed unit of a network node from a user equipment, a request to receive configured grant resources for small data transmissions in a cell; in response to receiving the request, generating a configured grant-small data transmission configuration for the user equipment based on the received request; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; and receiving, from the centralised unit of the network node, an activation indication for the configured grantsmall data transmission configuration for the user equipment.

In an example, the user equipment is in RRC inactive mode.

In an example, the apparatus is caused to perform, before receiving the request: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode; and in response to providing the indication, storing a context of the user equipment in the distributed unit of the network node.

In an example, the apparatus being caused to perform the generating the configured grant-small data transmission configuration comprises: identifying, at the distributed unit of the network node, that the user equipment has performed an intradistributed unit cell change; retrieving the stored context of the user equipment; and using the context of the user equipment to generate the configured grant-small data transmission configuration in the cell requested by the user equipment.

In an example, the request comprises a data payload comprising a logical channel identifier, wherein the apparatus being caused to perform the generating the configured grant-small data transmission configuration comprises: using the logical channel identifier to generate the configured grant-small data transmission configuration.

In an example, the apparatus is caused to perform: identifying a type of the user equipment using one or more bits of the inactive-radio network temporary identifier of the user equipment comprised in the request; and generating the configured grantsmall data transmission configuration for the user equipment based on the type of the user equipment.

In an example, the apparatus is caused to perform, before receiving the request: receiving, from the centralised unit of the network node, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises an associated payload size for data transmissions.

In an example, the apparatus is for a target cell.

In an example, the apparatus is for the distributed unit of the network node.

According to an aspect, there is provided an apparatus comprising: one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is for a user equipment; and providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment.

In an example, the apparatus is caused to perform: providing a radio resource control release message and the configured grant-small data transmission configuration to the user equipment.

In an example, the apparatus is caused to perform, before receiving the configured grant-small data transmission configuration: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode.

In an example, the apparatus is caused to perform, before receiving the request: providing, to the distributed unit, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises at least an associated payload size for data transmissions.

According to an aspect, there is provided an apparatus comprising: one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: providing, to a distributed unit of a network node, a request to receive configured grant resources for small data transmissions in a cell; and receiving, from a centralised unit of the network node, an activation indication for a configured grant-small data transmission configuration for a user equipment.

In an example, the apparatus is caused to perform: providing, to the distributed unit of the network node, a radio resource control resume request with the request to receive configured grant resources for small data transmissions in a cell.

In an example, the user equipment is in radio resource control inactive mode.

In an example, the apparatus is for the user equipment.

A computer product stored on a medium may cause an apparatus to perform the methods as described herein.

An electronic device may comprise apparatus as described herein.

In the above, various aspects have been described. It should be appreciated that further aspects may be provided by the combination of any two or more of the various aspects described above.

Various other aspects and further embodiments are also described in the following detailed description and in the attached claims.

According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims. The embodiments that do not fall under the scope of the claims are to be interpreted as examples useful for understanding the disclosure.

List of abbreviations:

AF: Application Function

AMF: Access Management Function 1

AN: Access Network

BAT: Burst Arrival Time

BS: Base Station

CG: Configured Grant

CN: Core Network

CP: Control Plane

CU: Centralised Unit

DL: Downlink

DU: Distributed Unit

EDT: Early Data Transmission eNB: eNodeB gNB: gNodeB

HoT: Industrial Internet of Things

LTE: Long Term Evolution

MAC-1: Message Authentication Code - Integrity

MAC-CE: Medium Access Control-Control Element

NEF: Network Exposure Function

NG-RAN: Next Generation Radio Access Network

NF: Network Function

NR: New Radio

NRF: Network Repository Function

NW: Network

MS: Mobile Station

PCF Policy Control Function

PLMN: Public Land Mobile Network

PRB: Physical Resource Block

RAN: Radio Access Network

RF: Radio Frequency

SDT: Small Data Transmission

SI: System Information

SIB: System Information Block

SS: Search Space

SSB: Synchronization Signal block

SSS: Secondary Synchronization Signal SMF: Session Management Function

SRB: Signalling Radio Bearer

TA: Timing Advance

UE: User Equipment

UDR: Unified Data Repository

UDM: Unified Data Management

UL: Uplink

UP: User Plane

UPF: User Plane Function

3GPP: 3^rd Generation Partnership Project

5G: 5^th Generation

5GC: 5G Core network

5G-AN: 5G Radio Access Network

5GS: 5G System

Description of Figures

Embodiments will now be described, by way of example only, with reference to the accompanying Figures in which:

Figure 1 shows a schematic representation of a 5G system;

Figure 2 shows a schematic representation of a control apparatus;

Figure 3 shows a schematic representation of a terminal;

Figures 4a, 4b and 4c each show example signalling diagrams for random access channel procedures;

Figure 5 shows a schematic representation of an uplink medium access control protocol data unit;

Figure 6 shows an example signalling diagram between network entities and a user equipment;

Figure 7 shows another example signalling diagram between network entities and a user equipment;

Figure 8 shows another example signalling diagram between network entities and a user equipment;

Figure 9 shows another example signalling diagram between network entities and a user equipment; Figure 10 shows example signalling between a user equipment and network entities for an intra-d istributed unit handover;

Figure 11 shows example signalling between a user equipment and network entities for an inter-distributed unit handover;

Figure 12 shows an example signalling diagram between network entities;

Figure 13 shows an example method flow diagram performed by a network entity;

Figure 14 shows another example method flow diagram performed by another network entity;

Figure 15 shows another example method flow diagram performed by a user equipment; and

Figure 16 shows a schematic representation of a non-volatile memory medium storing instructions which when executed by a processor allow a processor to perform one or more of the steps of the method of Figures 13, 14 and 15.

Detailed description

Before explaining in detail some examples of the present disclosure, certain general principles of a wireless communication system and mobile communication devices are briefly explained with reference to Figures 1 to 3 to assist in understanding the technology underlying the described examples.

In a wireless communication system 100, such as that shown in Figure 1 , mobile communication devices/terminals or user apparatuses, and/or user equipments (UE), and/or machine-type communication devices 102 are provided wireless access via at least one base station (not shown) or similar wireless transmitting and/or receiving node or point. A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other devices. The communication device may access a carrier provided by a station or access point, and transmit and/or receive communications on the carrier.

In the following certain examples are explained with reference to mobile communication devices capable of communication via a wireless cellular system and mobile communication systems serving such mobile communication devices. Before explaining in detail the examples of disclose, certain general principles of a wireless communication system, access systems thereof, and mobile communication devices are briefly explained with reference to Figures 1 , 2 and 3 to assist in understanding the technology underlying the described examples.

Figure 1 shows a schematic representation of a 5G system (5GS) 100. The 5GS may comprises a device 102 such as user equipment or terminal, a 5G access network (5G-AN) 106, a 5G core network (5GC) 104, one or more network functions (NF), one or more application function (AF) 108 and one or more data networks (DN) 110.

The 5G-AN 106 may comprise one or more gNodeB (gNB) distributed unit functions connected to one or more gNodeB (gNB) centralized unit functions.

The 5GC 104 may comprise an access management function (AMF) 112, a session management function (SMF) 114, an authentication server function (ALISF) 116, a user data management (UDM) 118, a user plane function (UPF) 120, a network exposure function (NEF) 122 and/or other NFs. Some of the examples as shown below may be applicable to 3GPP 5G standards. However, some examples may also be applicable to 4G, 3G and other 3GPP standards.

In a communication system, such as that shown in Figure 1 , mobile communication devices/terminals or user apparatuses, and/or user equipments (UE), and/or machine-type communication devices are provided with wireless access via at least one base station or similar wireless transmitting and/or receiving node or point. The terminal is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other devices. The communication device may access a carrier provided by a station or access point, and transmit and/or receive communications on the carrier.

Figure 2 illustrates an example of a control apparatus 200 for controlling a function of the 5G-AN or the 5GC as illustrated on Figure 1 . The control apparatus may comprise at least one random access memory (RAM) 211 a, at least on read only memory (ROM) 211 b, at least one processor 212, 213 and an input/output interface 214. The at least one processor 212, 213 may be coupled to the RAM 211 a and the ROM 211 b. The at least one processor 212, 213 may be configured to execute an appropriate software code 215. The software code 215 may for example allow to perform one or more steps to perform one or more of the present aspects. The software code 215 may be stored in the ROM 211 b. The control apparatus 200 may be interconnected with another control apparatus 200 controlling another function of the 5G-AN or the 5GC. In some examples, each function of the 5G-AN or the 5GC comprises a control apparatus 200. In alternative examples, two or more functions of the 5G-AN or the 5GC may share a control apparatus.

Figure 3 illustrates an example of a terminal 300, such as the terminal illustrated on Figure 1 . The terminal 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a user equipment, a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, a machine-type communications (MTC) device, a Cellular Internet of things (CloT) device or any combinations of these or the like. The terminal 300 may provide, for example, communication of data for carrying communications. The communications may be one or more of voice, electronic mail (email), text message, multimedia, data, machine data and so on.

The terminal 300 may receive signals over an air or radio interface 307 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 3 transceiver apparatus is designated schematically by block 306. The transceiver apparatus 306 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

The terminal 300 may be provided with at least one processor 301 , at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 302a and the ROM 302a. The at least one processor 301 may be configured to execute an appropriate software code 308. The software code 308 may for example allow to perform one or more of the present aspects. The software code 308 may be stored in the ROM 302a.

The processor, storage and other relevant control apparatus may be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 304. The device may optionally have a user interface such as keypad 305, touch sensitive screen or pad, combinations thereof or the like. Optionally one or more of a display, a speaker and a microphone may be provided depending on the type of the device.

One or more of the following examples are associated with small data transmissions (SDT). The transmission of data packets typically requires an established Radio Resource Control (RRC) connection between a UE and base station. When an RRC connection has been established, then a UE is said to be in RRC_Connected mode. After period of inactivity, or if that UE is signalled to, then the UE changes to RRC_ldle/RRC_lnactive mode. Typically, if an idle device wants to communicate with the network, it requests to establish the RRC connection and request resources again. This may not be efficient for SDT. Three ways of enabling SDT in the uplink in, for example, a 5G system are shown as illustrated in Figures 4a, 4b and 4c.

Figure 4a shows an example signalling diagram for a 4-step random access channel (RACH) procedure for SDT. In Figure 4a, user-plane (UP) data is transmitted in Msg3 of the 4-step RACH procedure. For example, a small payload is multiplexed with an RRC Connection Resume Request message.

Figure 4b shows an example signalling diagram for a 2-step random access channel (RACH) procedure for SDT. In Figure 4b, UP data transmission happens with MsgA of the 2-step RACH procedure and specifically on the PUSCH resources that are pre-configured by the gNB and broadcast in system information with associated physical transmission parameters.

Figure 4c shows an example signalling diagram for configured grant (CG) based SDT. In Figure 4c, a UE in RRC_Connected state can receive a CG typel configuration that indicates the specific pre-configured PUSCH resources to be used for UL data transmission. This CG configuration can also be used when in RRCJnactive state as long as the timing alignment is valid.

In Figures 4a, 4b and 4c, the RRC-based approach is assumed. This includes the UE sending an RRC message including information about the UE identity and its authentication token (i.e. MAC-I). It is assumed that the RRC Resume Request message is used for this purpose and Figure 5 shows the UL MAC PDU. The RRC- less approach instead assumes that the RRC layer need not be involved and the necessary information, such as, for example, a UE identity and a UE authentication token, can be provided by the UE in the MAC header or as a MAC CE. Figure 5 shows a schematic representation of an uplink (UL) medium access control (MAC) protocol data unit (PDU). The content of the UL MAC PDU may be used for SDT Msg3 for the 4-step RACH procedure. The content of the UL MAC PDU may also be used for SDT Msg3 for the 2-step RACH procedure. The content of the UL MAC PDU may also be used for CG-based SDT transmission for the baseline RRC- based method.

In current systems, a CG-SDT configuration is allocated for a user equipment (UE) but is valid only in the last serving cell of the UE. For example, if a UE is to move the RRC-lnactive and is released upon a cell change, then the CG-SDT is no longer valid for the UE. After a cell change, there is no mechanism to provide a new CG-SDT configuration to the UE without a network interaction. When a UE performs cell change inside its radio access network notification area (RNA), the UE does not send an RAN Update (RNAU). In this way, the network is not aware of the location of the UEs in RRC Inactive state at a cell level. In order to generate a new CG-SDT configuration for the UE in a target/new cell, network entities will communicate with one other to generate said CG-SDT.

As the network interaction to allocate a new CG-SDT configuration after cell change does not use optimised signalling, the reconfiguration of the CG-SDT leads to additional latency, additional UE power consumption and additional signalling overhead. For example, the UE (e.g. if it has limited mobility) may request CG-SDT resources after it reselects to a cell inside its RNA. However, CG-SDT resources might be refused by the network (e.g. due to cell load). Also, acquiring a new CG-SDT configuration in the new cell entails latency and UE power consumption. For example, there is network signalling between a distributed unit (DU) and a controlling centralised unit user-plane (CU-CP). The DU and the CU may be comprised with a network node such as a base station. The base station may be, for example, an eNB or a gNB. The CU may be configured to provide functions related to higher protocol stacks than the that provided by the DU. For example, the CU may provide functions related to the service data adaption protocol (SDAP), the radio resource control (RRC) and the packet data convergence protocol (PDCP) protocol layers. The DU may provide functions related to the radio link control (RLC), medium access control (MAC) and physical (PHY) protocol layers. The base station may comprise a plurality of DUs. Each DU of the base station may support a plurality of different cells. The DU and the CU are involved in the procedure, with signalling required between both entities, as shown in Figure 6.

Figure 6 shows an example signalling diagram between network entities and a user equipment. Before the signalling between entities starts, it is assumed that the UE is in RRC connected mode. Figure 6 shows the CG-SDT configuration for a UE going from connected to inactive state.

First, the UE may request new CG-SDT resources after a cell change. This UE request for CG-SDT resources is sent from UE to the centralised unit control plane (CU-CP) via the distributed unit (DU) (not shown in Figure 6).

At step 1 of Figure 6, the CU-CP requests the DU to create and provide, to the CU-CP, a CG-SDT configuration for the UE. At step 2, the DU provides the CG-SDT to the CU-CP.

At step 3 and step 4 of Figure 6, the CU-CP sends to the UE the CG-SDT configuration via the DU. The CU-CP also sends an RRC release indication to the UE, which sends the UE to RRC inactive mode.

The UE context will be stored at the serving CU-CP when the UE goes inactive. In some examples, the UE context will also be stored at the serving DU.

In some examples, there is a shared responsibility between the DU and CU-CP in assigning a CG-SDT resource configuration to the UE, as the configuration depends on multiple aspects. For example, the DU may be aware of lower layer aspects of such configuration. The CU-CP may be aware of aspects such as the traffic characteristics of the UE. The traffic characteristics may be relevant to define, for example, the payload size and/or resource periodicity of the configuration.

Figure 7 shows another example signalling diagram between network entities and a UE. Figure 7 shows a CG-SDT resource reconfiguration, when the UE has moved to a new cell, wherein the DU remains the same. This is referred to as ‘intra- DU’. In the example of Figure 7, the last serving DU (DU1 ) has not stored a UE context.

As seen in Figure 7, DU1 shall monitor all CG-SDT occasions configured to any UEs in RRC Inactive. The DU1 is not monitoring for UE-specific CG-SDT occasions.

At steps 0a and 0b of Figure 7, the UE, which is in RRC inactive mode, provides an RRC resume request with SDT payload to the last serving CP, via DU1. DU1 is monitoring for this transmission from the UE.

At steps 1 and 2 of Figure 7, the CP and DU signal with one another to configure a UE context and CG-SDT for the UE. At steps 3a and 4 of Figure 7, the CG-SDT reconfiguration is provided to UE, after UE context setup at DU. The UE can perform CG-SDT after the new CG-SDT configuration is received.

Between steps 0 and 1 of Figure 7, and between steps 2 and 3 of Figure 7, the last serving DU1 will perform radio link control (RLC) protocol data unit (PDU) buffering and processing respectively.

Therefore, as seen in Figure 7, the CG-SDT configuration in a new cell is provided, to the UE, when the UE performs RACH based SDT.

Figure 8 shows another example signalling diagram between network entities and a UE. Figure 8 shows a CG-SDT resource reconfiguration, when the UE has moved to a new cell, wherein the DU remains the same. This is referred to as ‘intra- DU’.

In the example of Figure 8, the last serving DU (DU1 ) has stored a UE context. A difference between the signalling in Figure 8 compared to Figure 7 is that the UE context need not be setup by CU-CP, since the DU’s UE context is assumed to be already stored locally while the UE, configured with CG-SDT Configuration, when the UE is moved to RRC Inactive state. When the last serving DU1 stores the UE context there may be, for example, two options to identify the UE when it initiates an access to its last serving DU:

In a first example, the UE may be identified at last serving DU1 using an inactive radio network temporary identifier (l-RNTI) included, by the UE, in an RRC resume request message. In this case, the UE provides the l-RNTI in the RRC resume request message to the CP, via the DU. The DU and the CU identify the UE based on this I- RNTI, as both the DU and CU have stored the UE context.

In a second example, the UE is identified at the last serving DU1 using a physical uplink shared channel (PUSCH) resource and/or demodulation reference signal (DMRS) that the UE uses in making a transmission to the DU, as shown in step 0a of Fig 5. In the second example, the UE does not need to include the l-RNTI in the RRC resume request message for the DU/CU to identify the UE.

In steps 0a and 0b of Figure 8, the UE provides an SDT including CG-SDT configuration request to the CU, via the DU. The DU and CU can identify the UE as discussed above. In steps 1 and 2 of Figure 8, the CU and DU signal one another in order to request and generate an CG-SDT configuration for the UE. The generation of the CG- SDT, by the DU, may be based on, for example, traffic characteristics.

In step 3a of Figure 8, the CU will provide the newly generated CG-SDT configuration to the UE, as well as an RRC release indication.

Figure 9 shows another example signalling diagram between network entities and a UE. Figure 9 shows a CG-SDT resource reconfiguration when a UE move to a new cell, wherein the DU also changes. This is referred to as ‘inter-DU’.

At steps 0a and 0b of Figure 9, the UE provides a CG-SDT configuration request message to the last serving CU-CP, via the last serving DU1 .

At steps 1 to 3 of Figure 9, the CU-CP requests and receives a configuration for a CG-SDT from DU1. The CU-CP then provides an RRC release indication with the CG-SDT configuration to the UE. This causes the UE to go to RRC inactive.

At step 4 of Figure 9, the UE changes from cell 1 to cell 2. This causes the CG- SDT configuration received from the network to be released.

At steps 5 and 6 of Figure 9, the UE has some uplink data to be transmitted and performs an initial random access (RA) SDT transmission to the CU, via a target DU2. The transmission also includes an RRC resume request.

At steps 6 to 8b of Figure 9, the CU-CP requests and receives an updated CG- SDT configuration from DU2. The CU-CP then provides an RRC release indication with the updated CG-SDT configuration to the UE. The previous CG-SDT configuration and the updated CG-SDT configuration may be different.

Following step 8b of Figure 9, the UE is now configured for any SDT transmissions that may be performed, as long as the UE remains connected to the same cell.

At steps 8d to 10b of Figure 9, the UE two separate SDT transmissions to the network, using the updated CG-SDT configuration. DU2 is always monitoring for potential SDT transmissions from the UE, based on the updated CG-SDT configuration. Completed SDT transmissions from the UE will be provided to the CU.

In an example, in preconfigured UL Resources (PUR) based early data transmissions (EDT), a PUR configuration request may be provides by a UE to a network, while the UE is in RRC connected mode. When the network decides to move the UE to RRC idle mode, the network will provide a PUR configuration message within an RRC connection release message, to the UE. In this example, PUR will be enabled in the cell that the UE is connected to. In some examples, a UE is allowed to send a CG request message to request appropriate CG configuration from the network for CG-SDT, for example, using the UE assistance framework.

As shown above in the example signalling diagrams of Figures 6 to 9, when the UE moves to another cell, in order to generate an updated CG-SDT configuration, for both inter-DU and intra-DU, additional signalling is required. The additional signalling means that resources are used, and network latency may be increased.

One or more of the following examples propose improved signalling mechanisms for CG-SDT resource re-allocation for a UE that moves to a different cell. In examples, when a UE with a CG-SDT resources/configuration provisioned in the last serving cell, undergoes mobility to a new cell, the CG-SDT resources/configuration to be used in the new cell are efficiently reconfigured in the new cell. In the following examples, both ‘intra-DU’ and ‘inter-DU’ cell changes are considered.

In one or more examples related to intra-DU cell reselection, a last serving DU for a UE stores the context of the UE, when the UE goes to RRC inactive state. The UE context may be stored at the last serving DU. When the UE moves to a new cell, of the same DU (last serving DU), the CG-SDT resources will be assigned by the DU. This allows the DU to generate a new CG-SDT configuration without the need for the CU-CP to execute a F1 UE context setup procedure. In some examples, the decision for the DU to store the UE context may be based on UE assistance information. The UE assistance information may comprise, for example, a type of the UE, a mobility history of the UE, and a capability of the UE.

In some examples, a device such as, a robot, or an energy harvesting sensor may have very limited mobility and is therefore eligible for UE context storage at the DU. In this example, the robot or energy harvesting sensor may have limited mobility compared to, for example, a mobile phone.

In one or more examples, determining a CG-SDT resource configuration for the UE at the DU, without being requested by the CU-CP, may reduce signalling and latency. Furthermore, by ‘piggybacking’ the CG-SDT configuration from the DU to the CU-CP with an RRC resume request message received from the UE, can also reduce the signalling and latency.

These examples related to intra-DU will be discussed in more detail below, in particular alongside Figure 10. In one or more examples related to inter-DU cell reselection, a DU can generate an CG-SDT configuration without the involvement of CU-CP by using a default CG SDT configuration. In some examples, the default CG-SDT configuration may be based on a data radio bearer (DRB) type, a data size, and a type of the UE. In some examples, one or more bits of the l-RNTI of the UE may be used to identify pre-agreed types of DRBs and data sizes. It should be understood that when DRBs are referenced, signalling radio bearers are equally applicable.

In some examples, the DU can use the l-RNTI to identify a type of the UE, which enables the DU to prepare a default CG-SDT configurations for UEs, or ‘special’ UEs. A special UE is a UE which may be eligible to receive a CG-SDT configuration and are indicated to the DU, using the l-RNTI of the UE.

These examples related to inter-DU will be discussed in more detail below, in particular alongside Figure 11 .

Figure 10 shows an example signalling diagram between network entities and a user equipment. During the signalling the UE moves from a serving cell (cell 1 ) to a target cell (cell 2), wherein both cell 1 and cell 2 are of the same DU (DU1 ).

At S1000a, the UE provides a CG-SDT configuration request to the DU associated with cell 1. The CG-SDT request may be provided by the UE using RRC signalling. During S1000a, the UE is in RRC connected mode.

At S1000b, the DU1 transparently forwards the CG-SDT configuration request to the serving CU-CP.

At S1001 , CU-CP provides a request to allocate resources for a CG-SDT and provide the configuration from DU1 .

At S1002, the DU1 provides a CG-SDT configuration to the CU-CP.

At S1003a and S103b, the CU-CP provides an RRC release message comprising the CG-SDT configuration to the UE, via cell 1 of DU1. The reception of the RRC release message at the UE will cause the UE to enter RRC inactive mode.

DU1 then stores a UE context. In an example, the UE context may be stored locally at DU1. In another example, the UE context is stored externally to DU1 , at a location accessible to DU1 . The UE context may comprise, for example, at least one of: an l-RNTI of the UE, DRB details of the UE, an RLC context of the DRBs of the UE.

At S1004, the serving cell of the UE changes from cell 1 to cell 2. Due to this change, the CG-SDT configuration of the old cell (cell 1 ) is released. At S1005, there is a trigger for an SDT (uplink payload) at the UE. In another example, there is a trigger for a configured grant request at the UE.

At S1006, the UE provides an SDT transmission to cell 2. The SDT may comprise a request, to cell 2, for resources for SDTs. The request for resources may comprise an RRC resume request message. The request may comprise an RA-SDT transmission including an RRC resume request. The RRC resume request may comprise an l-RNTI of the UE. The transmission may take place via beam 1 of cell 2. In other examples, the transmission may take place via another beam of the cell 2.

In some examples, the UE can indicate the request for CG-SDT resources by including an identifier/indication in a RACH-based SDT procedure. In this way, an additional request message to be sent by the UE is saved, which means that transmission resources may be saved. Further, since the UE is in RRC inactive mode, it may also save power for the UE.

At S1007a, the DU1 determines to generate an updated CG-SDT configuration. In an example, the CG-SDT configuration may be generated by DU1 using the received SDT and/or request from the UE. The DU1 may determine the UE using the l-RNTI comprises within the RRC resume request. In an example, the updated CG- SDT configuration may be based on a logical channel (LCH) included in the payload of the transmission from the UE. In an example, the CG-SDT config update/reconfiguration may be triggered, by the DU, upon the UE providing an RA- SDT to the DU via the same last serving cell (but using a beam not configured with CG-SDT resources). In an example, the CG-SDT config update/reconfiguration may be triggered, by the DU, upon the UE performing an RA-SDT to the DU via a different cell than last serving cell (of the same serving DU).

In some examples, both an LCH ID and a UE context are used to generate the updated CG-SDT configuration. For example, the LCH ID helps to identify the bearer type for CG-SDT. For example, the UE context provides further details for the updated CG-SDT configuration including, for example, UE type, and payload size.

In some examples, a UE impact may be considered if there is CG-SDT request indication from UE. This means that the UE may explicitly send a CG-SDT request indication to the network. In an example, this may be done by including a parameter in RACH-based SDT. In another example, this may be done using a further message for the request, sent by the UE. In some example, the DU may generate the updated CG-SDT based on small data transmission context information, received in a message from the centralised unit, for each of at least one of: a type of the user equipment, a type of data radio bearer, and a type of signalling radio bearer, for the SDT received from the UE.

At S1007b, the DU1 provides the updated CG-SDT configuration to the CU-CP. The updated CG-SDT configuration may be provided with the RRC resume request received from the UE. The provision of the updated CG-SDT configuration means that the DU1 is proposing, to the CU-CP, that the updated CG-SDT configuration be used by the UE for SDTs. In some examples, the updated CG configuration may be different compared to the first CG-SDT configuration used by the UE. The CG-SDT configuration may be different because the serving cell of the DU is different.

At S1008a, the CU-CP provides an activation indication for the updated CG- SDT configuration to the DU1. The CU-CP may also provide an RRC release indication to the DU1 . The RRC release indication may comprise the updated CG-SDT configuration. In some examples, upon receiving the activation, the DU will reserve resources associated with the updated CG-SDT for a subsequent small data transmissions by the UE.

At S1008b, the DU1 provides, via cell 2, the RRC release indication comprising the updated CG-SDT configuration to the UE. Upon receiving the message, the UE will remain in RRC inactive mode.

At S1008c, in response to receiving the activation indication from the CU-CP, DU1 will monitor for potential transmissions from the UE using the updated CG-SDT configuration.

At S1008d, there is a trigger for a transmission at the UE. For example, the transmission may be an SDT transmission.

At S1009a, the UE performs a first transmission to cell 2. The first transmission may be an SDT using the updated CG-SDT configuration.

At S1009b, DU1 provides the received SDT to a CU-UP. The SDT may comprise one or more SDT packets.

At S1010a, the UE performs a second transmission to cell 2. The second transmission may be an SDT using the updated CG-SDT configuration.

At S1010b, DU1 provides the received SDT to the CU-UP. The SDT may comprise one or more SDT packets. The first and second transmissions are shown as examples only. In some other examples, the UE may not perform any transmissions using the updated CG-SDT configuration. In other examples, the UE may perform more than two separate transmissions using the updated CG-SDT configuration.

In an example, the UE context is stored in the last serving DU after the UE is moved to RRC inactive state. The UE context may include at least one of: bearer information, associated CU-UP tunnel information, and other parameters for SDT. The serving DU may use, for example, the l-RNTI of the UE to retrieve the stored context of a given UE. The l-RNTI of the UE may be provided by the UE in the RRC resume request message when initiating an SDT transmission. In another example, another UE identifier is used to retrieve the context. In another example, part of the l-RNTI is used to retrieve the context.

This context of the UE may be used by the DU1 in steps 1007a/1007b where an updated CG-SDT configuration is to be allocated to the UE based on an LCH ID in the UE’s SDT associated with the transmitted payload. The updated CG-SDT configuration may be based on the information retrieved from the UE context. For example, the DRBs eligible for SDT, and/or the DRB’s payload size.

Figure 11 shows an example signalling diagram between network entities and a user equipment. During the signalling the UE moves from a serving cell to a target cell, wherein the serving cell is of DU1 and the target cell is of DU2.

At S1100a, the UE provides a CG-SDT configuration request to the serving cell. The CG-SDT may be provided by the UE using RRC signalling. During S1100a, the UE is in RRC connected mode.

At S1100b, the DU1 forwards the CG-SDT configuration request to the serving CU-CP.

At S1101 , CU-CP provides a request for a CG-SDT configuration from DU1 .

At S1102, the DU1 provides a CG-SDT configuration to the CU-CP.

At S1103a and S103b, the CU-CP provides an RRC release message comprising the CG-SDT configuration to the UE, via the serving cell of DU1. The reception of the RRC release message at the UE will cause the UE to enter RRC inactive mode.

At S1104, the serving cell of the UE changes from the serving cell of DU1 to the target cell of DU2. Due to this change, the CG-SDT configuration is released. At S1105, there is a trigger for an SDT (uplink payload) at the UE. In another example, there is a trigger for a configured grant request at the UE.

At S1106, the UE provides an SDT to the target cell. The SDT may comprise a request, to the target cell, for resources for a subsequent SDT. The request for resources may comprise an RRC resume request message. The request may comprise an RA-SDT transmission including an RRC resume request. The RRC resume request may comprise an l-RNTI of the UE. The UE may acquire a valid timing advance (TA) via the RA-SDT. In some examples, the UE also provides a medium access control control element (MAC CE) with the resource request. In some examples, the UE can indicate the request for CG-SDT resources by including an identifier/indication in a RACH-based SDT procedure.

The transmission of the request may take place via beam 1 of the target cell. In other examples, the transmission of the request may take place via another beam of the target cell.

At S1107a, the DU2 determines to generate an updated CG-SDT configuration. In some examples, the CG-SDT configuration may be generated by DU2 based on the received SDT and/or request from the UE.

In some examples, the DU2 can generate the CG-SDT configuration based on the received l-RNTI (from the RRC resume request) to indicate the type of UE that provided the request, to enable the DU2 to generate the configuration.

In some examples, the DU2 can generate the CG-SDT configuration based on a DRB type and/or data size of the intended SDT transmission from the UE in the target cell. One or more bits of the received l-RNTI (from the RRC resume request) may be used to identify DRB types and/or data size. One or more bits of the received l-RNTI may also be used to identify any other information that may be used to generate a CG-SDT configuration for the UE.

The DU2 may use a default CG SDT configuration for the updated CG-SDT configuration based on pre-agreed DRBs and/or SDT payload data sizes. For example, a default set of one or more DRBs that are eligible for SDTs is known at DU2, where each DRB in the set can be associated with a given payload size. The DU2 can select an DRB from the set of DRBs based on the payload size of the received SDT from the UE. The default set of one or more DRBs that are eligible for allocation of such CG-SDT configuration and the SDT data size may be signalled by the CU-CP to the DU at the time of DRB setup in RRC Connected mode. For example, the default set of one or more DRBs may be signalled using the F1 UE context setup and/or modification procedure. The types of DRB may be configured by the operator. In other examples, the types of DRBs and their corresponding SDT payload size are determined by a vendor based on artificial intelligence/machine learning (AI/ML) methods. For example, by gathering information regarding the users of CG-SDT resources, the most common DRB types used by them and the payload sizes transmitted by such users can be determined. The DRB type may be determined by the CU-CP based on the characteristics of the PDU session.

In some examples, upon receiving the SDT transmission from the UE including the resource request indication, via beaml , the DU2 can generate an updated CG- SDT configuration for the new cell for the UE. If the transmission is received via beam 1 , then the CG-SDT may include PUSCH/DMRS resources that are associated with the serving beam 1 of the target cell.

In examples, if the UE transmits small data together with the RA-SDT to DU2, the small data is sent to the CU-UP using one of the existing known methods.

In examples, the CG-SDT configuration for the UE may not be provided by the DU. For example, the DU may not provide a CG-SDT configuration in a case of overload of resources at the DU.

At S1107b, the DU2 provides the updated CG-SDT configuration to the CU-CP. In some examples, the DU2 provides the updated CG-SDT configuration to the CU- CP with an RRC resume request.

In some examples, the DU2 can provide the updated CG-SDT configuration per beam. In some examples, the DU2 can provide the updated CG-SDT configuration per cell of the DU2.

In some examples, the DU2 can provide the updated CG-SDT configuration based on one or more traffic demands upfront to the CU-CP. In this example, one or more CG-SDT configurations can be transmitted to the CU-CP before the UE requests for CG resources which can be received by the DU (in S1106/S1107). In this way, the CU-CP can select one of the received CG-SDT configurations for the UE from the one or more CG-SDT configurations generated and provided earlier by the DU2.

In some examples, the provisioning of the updated CG-SDT reconfiguration to the UE from the CU-CP may not occur. In some examples, the CU-CP may not provide the CG-SDT to the UE if, for example, there is a case of network overload. At S1108a, the CU-CP provides, to DU2, an activation indication for the updated CG-SDT configuration for the UE. In some examples, the CU-CP may also provide an RRC release indication. In some examples, upon receiving the activation, the DU will reserve resources associated with the updated CG-SDT for a subsequent small data transmissions by the UE.

In some examples, the CU-CP or DU2 is able to re-configure the updated CG- SDT configuration as necessary, when the UE is not camping in the target cell.

At S1108b, the DU2 provides, via the target cell, the RRC release indication comprising the updated CG-SDT configuration to the UE. Upon receiving the message, the UE will remain in RRC inactive mode.

At S1108c, in response to receiving the activation indication from the CU-CP, DU2 will monitor for potential transmissions from the UE using the updated CG-SDT configuration.

At S1108d, there is a trigger for a transmission at the UE. For example, the transmission may be an SDT transmission.

At S1109a, the UE performs a first transmission to the target cell. The first transmission may be an SDT using the updated CG-SDT configuration.

At S1109b, DU2 provides the received SDT to a CU-UP. The SDT may comprise one or more SDT packets.

At S1110a, the UE performs a second transmission to the target cell. The second transmission may be an SDT using the updated CG-SDT configuration.

At S1110b, DU2 provides the received SDT to the CU-UP. The SDT may comprise one or more SDT packets.

The first and second transmissions are shown as examples only. In some other examples, the UE may not perform any transmissions using the updated CG-SDT configuration. In other examples, the UE may perform more than two separate transmissions using the updated CG-SDT configuration.

In Figures 10 and 11 , the DU1 and serving CU may be part of a network node. A network node may be, for example, a base station.

In some examples, mapping between a UE type and default CG-SDT (CU CP) context information can be obtained by the DU in advance. In examples, this information can be obtained through an F1 setup procedure. This can be seen in Figure 12.

Figure 12 shows an example signalling diagram between network entities. At S1201 , the DU provides an F1 setup request message to the CU-CP.

At S1203, the CU-CP sends an F1 setup response message. In some examples, the F1 setup response message may comprise a list of UE types, and associated default SDT context information related to each UE type.

In some examples, the CU-CP of the gNB can send to one or more DUs, the default SDT context information per UE, or per DRB type, that will be further encoded within l-RNTI. Then, if a UE re-connects to a cell of another DU of same gNB, that DU already has the default SDT context information to build the updated CG SDT configuration. If the DU did not know about the default SDT context information, then the CU-CP would have sent this information in an F1 UE context setup message, at the request of the DU.

In this way, one or more of the examples discussed above means that there is a reduction in the amount of resources used when a UE moves to a new cell and requires an SDT configurations. Furthermore, the network latency can be reduced. This is due to fewer signalling steps being performed for the UE to receive the updated SDT configuration from the network. In this way, an efficient mechanism for providing an SDT configuration to a UE, after a cell change, is presented.

Figure 13 shows an example method flow performed by an apparatus. The apparatus may be comprised within a network entity. In an example, the network entity may be a distributed unit. The distributed unit may be comprised in a network node. A network node may be a base station in some examples, such as an eNB or gNB.

In S1301 , the method comprises receiving, at a distributed unit of a network node from a user equipment, a small data transmission in a cell.

In S1303, the method comprises in response to receiving the small data transmission, determining to generate a configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission.

In S1305, the method comprises generating the configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission;

In S1307, the method comprises providing, to a centralised unit of the network node, the configured grant-small data transmission configuration. In S1309, the method comprises receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment.

In S1311 , the method comprises in response to receiving the activation indication, reserving resources associated with the configured grant-small data transmission configuration for a subsequent small data transmission.

Figure 14 shows an example method flow performed by an apparatus. The apparatus may be comprised within network entity. In an example, the network entity may be a centralised unit. The centralised unit may be comprised in a network node.

In S1401 , the method comprises receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration for a user equipment generated by the distributed unit of the network node, wherein the configured grantsmall data transmission configuration is received within a message comprising a radio resource control message

In S1403, the method comprises determining to activate the configured grantsmall data transmission configuration for the user equipment.

In S1405, the method comprises providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment.

In S1407, the method comprises providing a radio resource control release message to the user equipment including the configured grant-small data transmission configuration when the activation indication is provided to the distributed unit.

Figure 15 shows an example method flow performed by an apparatus. In an example, the apparatus may be comprised within a user equipment. In an example, the apparatus may be comprised within a terminal.

In S1501 , the method comprises providing, to a distributed unit of a network node within a small data transmission, a request for a configured grant small data transmission configuration for a serving cell; and

In S1503, the method comprises receiving, from a centralised unit of the network node, a configured grant-small data transmission configuration to be used by a user equipment in the serving cell.

Figure 16 shows a schematic representation of non-volatile memory media 1600a (e.g. computer disc (CD) or digital versatile disc (DVD)) and 1600b (e.g. universal serial bus (USB) memory stick) storing instructions and/or parameters 1602 which when executed by a processor allow the processor to perform one or more of the steps of the methods of Figure 13, Figure 14 or Figure 15.

It is noted that while the above describes example embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

The examples may thus vary within the scope of the attached claims. In general, some embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although embodiments are not limited thereto. While various embodiments may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The examples may be implemented by computer software stored in a memory and executable by at least one data processor of the involved entities or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any procedures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi core processor architecture, as non-limiting examples.

Alternatively, or additionally some examples may be implemented using circuitry. The circuitry may be configured to perform one or more of the functions and/or method steps previously described. That circuitry may be provided in the base station and/or in the communications device.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analogue and/or digital circuitry);

(b) combinations of hardware circuits and software, such as:

(i) a combination of analogue and/or digital hardware circuit(s) with software/firmware and

(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as the communications device or base station to perform the various functions previously described; and

(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example integrated device.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of some embodiments. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings will still fall within the scope as defined in the appended claims.

Claims

49 Claims:

1 . An apparatus comprising means configured to perform: receiving, at a distributed unit of a network node from a user equipment, a small data transmission in a cell; in response to receiving the small data transmission, determining to generate a configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; generating the configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and in response to receiving the activation indication, reserving resources associated with the configured grant-small data transmission configuration for a subsequent small data transmission.

2. The apparatus according to claim 1 , wherein the small data transmission comprises a request of the user equipment to receive a configured grant-small data transmission configuration, and wherein the determining to generate the configured grant-small data transmission configuration is based on the received request from the user equipment.

3. The apparatus according to claim 1 , wherein the determining to generate the configured grant-small data transmission configuration is based on at least one of: a stored indication associated with a: type of the user equipment, and/or a type of data radio bearer, and/or a type of signalling radio bearer, which is involved in the small data transmission; an indication stored in a context associated with the user equipment involved in the small data transmission; and an indication stored in a context associated with one of: the data radio bearer and/or the signalling radio bearer involved in small data transmission. 50

4. The apparatus according to any of claims 1 to 3, wherein the small data transmission comprises a radio resource control message, which is provided to the centralised unit of the network node with the configured grant-small data transmission configuration.

5. The apparatus according to claim 4, wherein the radio resource control message is: a radio resource control resume request, or a radio resource control message which is related to small data transmission.

6. The apparatus according to any of claims 1 to 5, wherein the small data transmission comprises an inactive-radio network temporary identifier of the user equipment.

7. The apparatus according to any of claims 1 to 6, wherein the means are configured to perform, before receiving the small data transmission: providing, to the user equipment, an indication for the user equipment to move to radio resource control inactive mode; and in response to providing the indication, storing a context of the user equipment in the distributed unit of the network node.

8. The apparatus according to claim 7, wherein the context of the user equipment is stored in the distributed unit based on a predefined criteria, wherein the predefined criteria comprises at least one of: user equipment assistance information, a type of the user equipment, and a mobility history of the user equipment.

9. The apparatus according to claim 7 or claim 8, wherein the means configurated to perform the generating the configured grant-small data transmission configuration comprises: identifying, at the distributed unit of the network node, that there is a stored context of the user equipment using the received inactive-radio network temporary identifier; retrieving the stored context of the user equipment; and 51 using the context of the user equipment to generate the configured grant-small data transmission configuration in the cell.

10. The apparatus according to any of claims 7 to 9, wherein the context of the user equipment comprises at least one of: data radio bearers eligible for small data transmission, and a data payload size for each of the data radio bearers.

11. The apparatus according to any of claims 1 to 10, wherein the small data transmission comprises a data payload comprising a logical channel identifier, wherein the means configured to perform the generating the configured grant-small data transmission configuration comprises: using the logical channel identifier to generate the configured grant-small data transmission configuration.

12. The apparatus according to claim 6, wherein the means are configured to perform: identifying at least one of: a type of the user equipment, a type of data radio bearer, and a type of signalling radio bearer, requested by the user equipment using one or more bits of the inactive-radio network temporary identifier of the user equipment comprised in the small data transmission; and generating the configured grant-small data transmission configuration for the user equipment based on the at least one of: the type of the user equipment, the type of data radio bearer, and the type of signalling radio bearer.

13. The apparatus of claim 12, wherein the means configured to perform the generating of the configured grant-small data transmission configuration is based on small data transmission context information, received in a message from the centralised unit, for each of the at least one of: the type of the user equipment, the type of data radio bearer, and the type of signalling radio bearer.

14. The apparatus according to claim 1 to 6, wherein the means are configured to perform, before receiving the small data transmission: 52 receiving, from the centralised unit of the network node, a set of one or more data radio bearers that are eligible for small data transmissions, wherein each data radio bearer in the set comprises an associated payload size for data transmissions.

15. The apparatus according to claim 14, wherein the means configurated to perform the generating the configured grant-small data transmission configuration comprises: selecting a data radio bearer from the set of one or more data radio bearers based on the received message; and generating the configured grant-small data transmission configuration using the selected data radio bearer and associated payload size.

16. The apparatus according to claim 14 or claim 15, wherein the set of one or more data radio bearers are received at a time of a data radio bearer setup procedure using one of: a user equipment context setup, and a user equipment modification procedure.

17. The apparatus according to any of claims 1 to 16, wherein the configured grantsmall data transmission configuration for the user equipment is different to a previous configured grant-small data transmission configuration used by the user equipment when connected to a last serving cell.

18. An apparatus comprising means configured to perform: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration for a user equipment generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is received within a message comprising a radio resource control message; determining to activate the configured grant-small data transmission configuration for the user equipment; providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and providing a radio resource control release message to the user equipment including the configured grant-small data transmission configuration when the activation indication is provided to the distributed unit.

19. The apparatus according to claim 18, wherein the means are configured to perform, before receiving the configured grant-small data transmission configuration: providing, to the distributed unit, at least one of: an indication to keep the user equipment context when moving the user equipment to radio resource control inactive mode; an indication to keep the user equipment context when moving the user equipment to radio resource control inactive mode together with an indication to generate a configured grant-small data transmission configuration at a subsequent small data transmission; a set of one or more data radio bearers and/or signalling radio bearers that are eligible for small data transmissions, wherein each data radio bearer and/or signalling radio bearers in the set comprises at least an associated payload size for data transmissions; and a set of data radio bearer types and/or signalling radio bearers types or user equipment types that are eligible for generating a configured grant configuration at next small data transmission.

20. The apparatus according to claim 19, wherein the set of one or more data radio bearers and/or signalling radio bearers are provided at a time of a data radio bearer and/or signalling radio bearer setup procedure using one of: a user equipment context setup, and a user equipment modification procedure.

21 . An apparatus according to claim 19 or 20, wherein the means are configured to perform: providing, as part of a non-user equipment associated message to the distributed unit, a set of small data transmission context pieces of information associated with a data radio bearer type and/or a signalling radio bearer type and/or a user equipment type to be used when generating a configured grant configuration.

22. An apparatus comprising means configured to perform: providing, to a distributed unit of a network node within a small data transmission, a request for a configured grant small data transmission configuration for a serving cell; and receiving, from a centralised unit of the network node, a configured grantsmall data transmission configuration to be used by a user equipment in the serving cell.

23. The apparatus according to claim 22, wherein the request is indicated in a random access channel.

24. The apparatus according to claim 22 or 23, wherein the request is comprised in a message terminated in the distributed unit of the network node.

25. The apparatus according to any of claims 22 to 24, wherein the means are configured to perform: providing, to the distributed unit of the network node, within the small data transmission a radio resource control message together with the request to receive configured grant resources for small data transmissions in a cell.

26. The apparatus of claim 25 wherein the radio resource control message is a radio resource control resume request message.

27. The apparatus according to any of claims 22 to 26, wherein the means are configured to perform: receiving, from the centralised unit of the network node, a radio resource control release message with the configured grant-small data transmission configuration for the user equipment.

28. The apparatus according to any of claims 22 to 27, wherein the small data transmission comprises an inactive-radio network temporary identifier of the user equipment.

29. The apparatus according to any of claims 22 to 28, wherein the user equipment is in radio resource control inactive mode. 55

30. The apparatus according to any of claims 22 to 29, wherein the apparatus is for the user equipment.

31 . A method comprising: receiving, at a distributed unit of a network node from a user equipment, a small data transmission in a cell; in response to receiving the small data transmission, determining to generate a configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; generating the configured grant-small data transmission configuration for the cell for the user equipment based on the received small data transmission; providing, to a centralised unit of the network node, the configured grant-small data transmission configuration; receiving, from the centralised unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and in response to receiving the activation indication, reserving resources associated with the configured grant-small data transmission configuration for a subsequent small data transmission.

32. A method comprising: receiving, from a distributed unit of a network node, a configured grant-small data transmission configuration for a user equipment generated by the distributed unit of the network node, wherein the configured grant-small data transmission configuration is received within a message comprising a radio resource control message; determining to activate the configured grant-small data transmission configuration for the user equipment; providing, to the distributed unit of the network node, an activation indication for the configured grant-small data transmission configuration for the user equipment; and 56 providing a radio resource control release message to the user equipment including the configured grant-small data transmission configuration when the activation indication is provided to the distributed unit.

33. A method comprising: providing, to a distributed unit of a network node within a small data transmission, a request for a configured grant small data transmission configuration for a serving cell; and receiving, from a centralised unit of the network node, a configured grant- small data transmission configuration to be used by a user equipment in the serving cell.