WO2021165041A1

WO2021165041A1 - Coordination of serving cell configuration

Info

Publication number: WO2021165041A1
Application number: PCT/EP2021/052491
Authority: WO
Inventors: Subramanya CHANDRASHEKAR; Ethiraj Alwar
Original assignee: Nokia Technologies Oy
Priority date: 2020-02-17
Filing date: 2021-02-03
Publication date: 2021-08-26

Abstract

There is provided an apparatus comprising means for transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations. There is also provided an apparatus comprising means for receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

Description

TITEL

COORDINATION OF SERVING CELL CONFIGURATION

FIELD

The present application relates to a method, apparatus, system and computer program and in particular but not exclusively to coordination of serving cell configuration in wireless networking.

BACKGROUND

A communication system can be seen as a facility that enables communication sessions between two or more entities such as user terminals, base stations and/or other nodes by providing carriers between the various entities involved in the communications path. A communication system can 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, video, 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.

In a wireless communication system at least a part of a communication session between at least two stations occurs over a wireless link. Examples of wireless systems comprise public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). Some wireless systems can be divided into cells, and are therefore often referred to as cellular systems.

A user can access the communication system by means of an appropriate communication device or terminal. A communication device of a user may be referred to as user equipment (UE) or user device. 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 users. The communication device may access a carrier provided by a station, for example a base station of a cell, and transmit and/or receive communications on the carrier. The communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters which shall be used for the connection are also typically defined. One example of a communications system is UTRAN (3G radio). Other examples of communication systems are the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology and so-called 5G or New Radio (NR) networks. NR is being standardized by the 3rd Generation Partnership Project (3GPP).

SUMMARY

According to an aspect there is provided an apparatus comprising means for: transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations

The message comprising cell specific information comprising the one or more serving cell configurations may comprise a single serving cell configuration.

The message comprising the one or more serving cell configurations may comprise a plurality of serving cell configurations and an identifier of a default serving cell configuration comprised in the plurality of serving cell configurations.

The default serving cell configuration may be based on at least one of a user equipment service type and a user equipment category.

The means may be for: receiving, at the first node from the second node, a first further message comprising at least one of an indication of a user equipment resource request and a user equipment capability; selecting one of the one or more serving cell configurations based on the first further message; and transmitting, from the first node to the second node, a first further response message comprising an indication of an identifier corresponding to the selected one of the one or more serving cell configurations.

The first further message may be a user equipment context setup request or a user equipment context modification request. The means may be for: determining, at the first node, a change in cell configuration supported by the first node; transmitting, from the first node to the second node, a second further message comprising cell specific information based on the determined change in cell configuration supported by the first node; and receiving, at the first node from the second node, a second further response message acknowledging receipt of the further message comprising cell specific information.

According to an aspect, there is provided an apparatus comprising means for: receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

Encoding the user equipment specific message for transmission to the user equipment may be based on the single serving cell configuration.

The message comprising cell specific information comprising the one or more serving cell configurations may comprise a plurality of serving cell configurations and an identifier of a default serving cell configuration comprised in the plurality of serving cell configurations.

Encoding the user equipment specific message for transmission to the user equipment may be based on the serving cell configuration corresponding to the received identifier of the default serving cell configuration.

The means may be for: transmitting, from the second node to the first node, a first further user equipment specific message comprising at least one of an indication of a user equipment resource request and a user equipment capability; and receiving, at the second node from the first node, a first further response message comprising an indication of an identifier corresponding to a selected one of the one or more serving cell configurations. Encoding the user equipment specific message for transmission to the user equipment may be based on the serving cell configuration corresponding to the received identifier of the selected serving cell configuration.

The first further user equipment specific message may be a user equipment context setup request or a user equipment context modification request.

The means may be for determining, by the second node, a number of serving cell configurations supported by the first node.

The means may be for: receiving, at the second node from the first node, a second further message comprising cell specific information based on a determined change in cell configuration supported by the first node; and updating the cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations based on the received second further message.

The means may be for: receiving at second node, from a further first node, a third further message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations for the further first node; determining at the second node that the user equipment is handed over from the first node to the further node; and encoding the user equipment specific message for transmission to the user equipment based on one of the new one or more serving cell configurations supported by the further first node.

The user equipment may comprise one of: a user equipment, an eNB, and a gNB.

The serving cell configuration may comprise a bandwidth part configuration.

The bandwidth part configuration may comprise at least one of an uplink bandwidth part configuration and a downlink bandwidth part configuration.

The first node may comprise a distributed unit and the second node may comprise a central unit.

According to an aspect, there is provided an apparatus comprising: at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to:transmit, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

The at least one memory and at least one processor may be configured to cause the apparatus to: receive, at the first node from the second node, a first further message comprising at least one of an indication of a user equipment resource request and a user equipment capability; select one of the one or more serving cell configurations based on the first further message; and transmit, from the first node to the second node, a first further response message comprising an indication of an identifier corresponding to the selected one of the one or more serving cell configurations.

The first further message may be a user equipment context setup request or a user equipment context modification request.

The at least one memory and at least one processor may be configured to cause the apparatus to: determine, at the first node, a change in cell configuration supported by the first node; transmitting, from the first node to the second node, a second further message comprising cell specific information based on the determined change in cell configuration supported by the first node; and receive, at the first node from the second node, a second further response message acknowledging receipt of the further message comprising cell specific information.

According to an aspect, there is provided an apparatus comprising: at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receive, at the second node, a connection request message from a user equipment; encode a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmit the encoded message to the user equipment in a response to the connection request message.

The at least one memory and at least one processor may be configured to cause the apparatus to: encode the user equipment specific message for transmission to the user equipment based on the single serving cell configuration.

The at least one memory and at least one processor may be configured to cause the apparatus to: encode the user equipment specific message for transmission to the user equipment based on the serving cell configuration corresponding to the received identifier of the default serving cell configuration.

The at least one memory and at least one processor may be configured to cause the apparatus to: transmit, from the second node to the first node, a first further user equipment specific message comprising at least one of an indication of a user equipment resource request and a user equipment capability; and receive, at the second node from the first node, a first further response message comprising an indication of an identifier corresponding to a selected one of the one or more serving cell configurations.

The at least one memory and at least one processor may be configured to cause the apparatus to: encode the user equipment specific message for transmission to the user equipment based on the serving cell configuration corresponding to the received identifier of the selected serving cell configuration.

The first further user equipment specific message may be a user equipment context setup request or a user equipment context modification request. The at least one memory and at least one processor may be configured to cause the apparatus to: determine, by the second node, a number of serving cell configurations supported by the first node.

The at least one memory and at least one processor may be configured to cause the apparatus to: receive, at the second node from the first node, a second further message comprising cell specific information based on a determined change in cell configuration supported by the first node; and update the cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations based on the received second further message.

The at least one memory and at least one processor may be configured to cause the apparatus to: receive, at second node from a further first node, a third further message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations for the further first node; determine, at the second node, that the user equipment is handed over from the first node to the further node; and encode the user equipment specific message for transmission to the user equipment based on one of the new one or more serving cell configurations supported by the further first node.

The user equipment may comprise one of: a user equipment, an eNB, and a gNB.

The serving cell configuration may comprise a bandwidth part configuration.

According to an aspect, there is provided a method comprising: transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

The message comprising cell specific information comprising the one or more serving cell configurations may comprise a single serving cell configuration. The message comprising the one or more serving cell configurations may comprise a plurality of serving cell configurations and an identifier of a default serving cell configuration comprised in the plurality of serving cell configurations.

The method may comprise: receiving, at the first node from the second node, a first further message comprising at least one of an indication of a user equipment resource request and a user equipment capability; selecting one of the one or more serving cell configurations based on the first further message; and transmitting, from the first node to the second node, a first further response message comprising an indication of an identifier corresponding to the selected one of the one or more serving cell configurations.

The method may comprise: determining, at the first node, a change in cell configuration supported by the first node; transmitting, from the first node to the second node, a second further message comprising cell specific information based on the determined change in cell configuration supported by the first node; and receiving, at the first node from the second node, a second further response message acknowledging receipt of the further message comprising cell specific information.

According to an aspect, there is provided a method comprising: receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

The message comprising cell specific information comprising the one or more serving cell configurations may comprise a single serving cell configuration. Encoding the user equipment specific message for transmission to the user equipment may be based on the single serving cell configuration.

The method may comprise: transmitting, from the second node to the first node, a first further user equipment specific message comprising at least one of an indication of a user equipment resource request and a user equipment capability; and receiving, at the second node from the first node, a first further response message comprising an indication of an identifier corresponding to a selected one of the one or more serving cell configurations.

Encoding the user equipment specific message for transmission to the user equipment may be based on the serving cell configuration corresponding to the received identifier of the selected serving cell configuration.

The method may comprise: determining, by the second node, a number of serving cell configurations supported by the first node.

The method may comprise: receiving, at the second node from the first node, a second further message comprising cell specific information based on a determined change in cell configuration supported by the first node; and updating the cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations based on the received second further message.

The method may comprise: receiving at second node, from a further first node, a third further message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations for the further first node; determining at the second node that the user equipment is handed over from the first node to the further node; and encoding the user equipment specific message for transmission to the user equipment based on one of the new one or more serving cell configurations supported by the further first node.

The user equipment may comprise one of: a user equipment, an eNB, and a gNB.

The serving cell configuration may comprise a bandwidth part configuration.

According to an aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at least the following: transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

The apparatus may be caused to perform: receiving, at the first node from the second node, a first further message comprising at least one of an indication of a user equipment resource request and a user equipment capability; selecting one of the one or more serving cell configurations based on the first further message; and transmitting, from the first node to the second node, a first further response message comprising an indication of an identifier corresponding to the selected one of the one or more serving cell configurations. The first further message may be a user equipment context setup request or a user equipment context modification request.

The apparatus may be caused to perform: determining, at the first node, a change in cell configuration supported by the first node; transmitting, from the first node to the second node, a second further message comprising cell specific information based on the determined change in cell configuration supported by the first node; and receiving, at the first node from the second node, a second further response message acknowledging receipt of the further message comprising cell specific information.

According to an aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at least the following: receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

The apparatus may be caused to perform: transmitting, from the second node to the first node, a first further user equipment specific message comprising at least one of an indication of a user equipment resource request and a user equipment capability; and receiving, at the second node from the first node, a first further response message comprising an indication of an identifier corresponding to a selected one of the one or more serving cell configurations.

The apparatus may be caused to perform: determining, by the second node, a number of serving cell configurations supported by the first node.

The apparatus may be caused to perform: receiving, at the second node from the first node, a second further message comprising cell specific information based on a determined change in cell configuration supported by the first node; and updating the cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations based on the received second further message.

The apparatus may be caused to perform: receiving at second node, from a further first node, a third further message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations for the further first node; determining at the second node that the user equipment is handed over from the first node to the further node; and encoding the user equipment specific message for transmission to the user equipment based on one of the new one or more serving cell configurations supported by the further first node.

The user equipment may comprise one of: a user equipment, an eNB, and a gNB.

The serving cell configuration may comprise a bandwidth part configuration.

The first node may comprise a distributed unit and the second node may comprise a central unit. According to an aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any of the preceding aspects.

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

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 representation of a network system according to some example embodiments;

Figure 2 shows a representation of a control apparatus according to some example embodiments;

Figure 3 shows a representation of an apparatus according to some example embodiments; Figure 4 shows a method according to some example embodiments;

Figure 5 shows a method according to some example embodiments;

Figure 6 shows a method according to some example embodiments;

Figure 7 shows a method according to some example embodiments;

Figure 8 shows a method according to some example embodiments; and Figure 9 shows a method according to some example embodiments.

DETAILED DESCRIPTION

In the following certain embodiments 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 exemplifying embodiments, 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). The 5GS may be comprised by a terminal or user equipment (UE), a 5G radio access network (5GRAN) or next generation radio access network (NG-RAN), a 5G core network (5GC), one or more application function (AF) and one or more data networks (DN).

The 5G-RAN may comprise one or more gNodeB (GNB) or one or more gNodeB (GNB) distributed unit functions connected to one or more gNodeB (GNB) centralized unit functions. The 5GC may comprise the following entities: Network Slice Selection Function (NSSF); Network Exposure Function; Network Repository Function (NRF); Policy Control Function (PCF); Unified Data Management (UDM); Application Function (AF); Authentication Server Function (AUSF); an Access and Mobility Management Function (AMF); and Session Management Function (SMF).

Figure 2 illustrates an example of a control apparatus 200 for controlling a function of the 5GRAN or the 5GC as illustrated on Figure 1. The control apparatus may comprise at least one random access memory (RAM) 211a, at least on read only memory (ROM) 211b, 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 211a and the ROM 211b. 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 211b. The control apparatus 200 may be interconnected with another control apparatus 200 controlling another function of the 5GRAN or the 5GC. In some embodiments, each function of the 5GRAN or the 5GC comprises a control apparatus 200. In alternative embodiments, two or more functions of the 5GRAN 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, an Internet of things (loT) type communication 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 311a and the ROM 311b. 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 311b.

The processor, storage and other relevant control apparatus can 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 key pad 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.

A UE may be configured for operation in bandwidth parts (BWPs) of a serving cell. A bandwidth part is a contiguous set of physical resource blocks (PRBs) on a given carrier. The resource blocks may be selected from a contiguous subset of common resource blocks.

The UE may be configured by higher layers for the serving cell with a set of at most four bandwidth parts (BWPs). The UE may utilise the set of BWPs for reception (a so called downlink BWP set) in a downlink (DL) bandwidth. The higher layers may configure the UE using parameter BWP-Downlink or by parameter initialDownlinkBWP with a set of parameters configured by BWP-DownlinkCommon and BWP-DownlinkDedicated.

The UE be configured by the higher layers with a set of at most four BWPs for transmissions by the UE (a so called UL BWP set) in an UL bandwidth. The higher layers may configure the UE using parameter BWP-Uplink or by parameter initialUplinkBWP with a set of parameters configured by BWP-UplinkCommon and BWP-UplinkDedicated. In some examples, a UE may have a dedicated BWP configuration. The higher layers may provide the UE with a first active DL BWP for receptions using parameter firstActiveDownlinkBWP-ld and a first active UL BWP for transmissions on a carrier of the primary cell using parameter firstActiveUplinkBWP-ld.

The BWP may be used to configure generic parameters of a bandwidth part as defined in TS 38.211, clause 4.5, TS 38.213, clause 12, and TS 38.331.

For each serving cell, the network may configure at least an initial downlink BWP and one or more initial uplink BWPs. For example, if using a supplementary uplink (SUL), the network may configure two initial uplink BWPs. Furthermore, the network may configure additional uplink and downlink BWPs for a serving cell.

The uplink and downlink BWP configurations may be divided into common and dedicated parameters.

BWP configuration is key aspect of UE configuration in 5G MR-DC and SA deployments. The BWP may be configured as part of Serving Cell Configuration (Primary and Secondary Cell). The Serving Cell Configuration may be part of CellGroupConfig information element (IE) sent from the gNB to the UE. That is to say, the BWP configuration may be comprised in the CellGroupConfig IE.

A gNB may comprise a Central Unit (CU) and Distributed Unit (DU). The gNB-DU may be a logical node hosting RLC, MAC and PHY layers of the gNB, and its operation may be partly controlled by a gNB Central Unit (gNB-CU). One gNB-DU may support one or more cells. One cell may be supported by only one gNB-DU. The gNB-DU may terminate the F1 interface connected with the gNB-CU. The gNB-CU may be a logical node hosting RRC, SDAP and PDCP protocols of the gNB that controls the operation of one or more gNB-DUs. The gNB- CU may terminate the F1 interface connected with the gNB-DU. The gNB-CU may be connected to more than one gNB-DU, or may be connected to only one gNB-DU.

The CellGroupConfig IE may be encoded by a gNB Distributed Unit (gNB-DU). As such, the gNB-DU may control the encoding of the BWP configuration.

Having encoded the CellGroupConfig IE, the gNB-DU may send the encoded IE to the gNB- CU. The gNB-CU may then transparently copy the CellGroupConfig IE in RRC Messages (RRC Setup or RRC Reconfiguration) to be sent to the UE. The information may be BWP specific and not UE specific. That is to say, the information may be BWP specific, and configured per UE dependent on UE capability, and not be specific to the UE itself. There may be a limited number of BWPs.

Signalling of the BWP configuration may be encoded per UE by the gNB-DU and sent over the F1 interface to the gNB-CU. This may result in unnecessary signalling overhead over the F1 interface, and therefore impact on latency of UE associated procedures.

Furthermore, the size of the BWP configuration carried in the Cel I Group Con fig IE may be relatively big, and as such signalling of the CellGroup Con fig IE per UE may be bandwidth consuming.

For example, when a UE requests radio access bearer (RAB) establishment, signalling radio bearers (SRBs) and dedicated radio bearers (DRBs) may be set up at both the gNB-CU and the gNB-DU.

The gNB-CU may send a UE Context Setup Request or a UE Context Modification Request to the gNB-DU over the F1 interface based on whether the RAB request is for a SRB or DRB.

The gNB-DU may receive a request from the gNB-CU and send a UE Context Setup Response or UE Context Modification Response back to the gNB-CU. The response may include the BWP Configuration encoded by the gNB-DU. This may occur each time an SRB or DRB is set up for every UE.

As explained above, the BWP configuration may be comprised in the CellGroup Con fig IE, which is encoded by the gNB-DU. The gNB-DU may encode the following lEs when sending the UE Context Setup Response, UE Context Modification Response, or during Initial UL RRC Message Transfer

• CellGroupConfig. SpCellConfig. downlinkB WP-ToA ddModList

• CellGroupConfig. SpCellConfig. uplinkConfiguplinkB WP-ToA ddModList

An exemplary CellGroup Con fig IE is shown below:

CellGroupConfig SEQUENCE { cellGroupId CellGroupId,

Some example embodiments relate to mechanisms for optimizing the Uplink and Downlink BWP signalling. Some example embodiments leverage information intelligently at the gNB- CU.

In the following description, references are made to a BWP configuration. However, it should be understood that the methods relating to BWP configuration may also be applied to other Serving Cell Configurations that are at cell-level but configured per UE - for example, the CSI- MeasConfig IE.

In some example embodiments, the gNB-DU may send, to the gNB-CU, BWP configuration information. The BWP configuration information may comprise a list of dedicated BWP configurations and an ID for each BWP configuration. Each BWP configuration may be specific to a particular cell. When selecting a BWP for each individual UE, the gNB-DU may send an indication of the ID of the selected BWP to the gNB-CU.

The gNB-CU, on receiving the indication of ID of the selected BWP, may use the corresponding ID to look up the corresponding BWP configurations from the list received from the gNB-DU. The gNB-CU may then encode RRC Messages using the BWP configuration selected from the list based on the received index.

As such, some embodiments may provide a method where the gNB-DU does not need to encode and send the BWP configuration every time per UE. Instead, the BWP configurations may only be encoded and sent once, thereby reducing signalling overhead over the F1 interface and reducing bandwidth consumption.

In some example embodiments, the BWP configuration information may further comprise one or more of:

• An initial BWP for downlink and/or uplink communications and an ID for each initial BWP configuration; and

• A BWP inactivity timer.

In some example embodiments, for example in stand-alone New Radio, an initial BWP for downlink/uplink communications may not be used, and instead initial BWP information may be broadcast in a system information block (SIB).

In some example embodiments, there is provided a method comprising transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

In some example embodiments, there is provided a method comprising receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based in the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

Reference is made to Figure 4, which shows an example method for setting up communications between the gNB-DU 400 and gNB-CU 402 over the F1 interface according to some embodiments.

At step 404, the gNB-DU 400 sends a message comprising cell specific information over the F1 interface to the gNB-CU 402. For example, the message comprising cell specific information may comprise a setup request comprising a list of BWP configurations and a corresponding ID for each BWP configuration.

At step 406, the gNB-CU 402 may store the list of BWP configurations and corresponding IDs.

At step 408, the gNB-CU 402 sends a setup response over the F1 interface to the gNB-DU 400. The setup response may acknowledge receipt of the message comprising cell specific information. In some example embodiments, the gNB-DU 400 may support more than one dedicated BWP, and may indicate which of the more than one dedicated BWP is the default dedicated BWP based on a condition, for example the user equipment’s service type, or the user equipment category. In some examples, the gNB-DU 400 may only support a single dedicated BWP.

The gNB-CU 402 may determine the number of dedicated BWP that is supported by the gNB- DU, and perform one or more operations accordingly.

Reference is made to Figure 5, which shows an example method according to some embodiments.

In the example method of Figure 5, the gNB-DU 500 supports only a single dedicated BWP.

At step 504, the gNB-DU 500 sends a message comprising cell specific information, for example a setup request, over the F1 interface to the gNB-CU 502. The setup request may comprise a list of BWP configurations and a corresponding ID for each BWP configuration. In this example, as only a single dedicated BWP is supported by the gNB-DU 500, the list of BWP configurations comprises only a single BWP.

At step 506, the gNB-CU 502 may store the list of BWP configurations and corresponding IDs.

At step 508, the gNB-CU 502 sends a setup response over the F1 interface to the gNB-DU 500. The setup response may acknowledge receipt of the message comprising cell specific information.

At step 510, the gNB-CU 502 may receive a message comprising a communication request from the UE 516. In some example embodiments, the message may be received either directly from the UE, or from the UE via an eNB or gNB.

At step 512, the gNB-CU 502 may perform a communication setup procedure. The gNB-CU 502 may use the single dedicated BWP received from the gNB-DU 500 in the setup request at step 504 to encode messages specific to the user equipment using the single dedicated BWP.

At step 514, the gNB-CU 502 may send the encoded messages to UE 516. Reference is made to Figure 6, which shows an example method according to some embodiments.

In the example method of Figure 6, the gNB-DU 600 supports more than one dedicated BWP, one of which is designated as a default BWP.

At step 604, the gNB-DU 600 sends a message comprising cell specific information, for example a setup request as described previously, over the F1 interface to the gNB-CU 602. The setup request may comprise a list of BWP configurations and a corresponding ID for each BWP configuration. The setup request also comprises an indication of an ID corresponding to the BWP configuration that is designated as the default BWP configuration.

At step 606, the gNB-CU 602 may store the list of BWP configurations and corresponding IDs.

At step 608, the gNB-CU 602 sends a setup response over the F1 interface to the gNB-DU 600. The setup response may acknowledge receipt of the message comprising cell specific information.

At step 610, the gNB-CU 602 may receive a message comprising a communication request from the UE 616. In some example embodiments, the message may be received either directly from the UE, or from the UE via an eNB or gNB

At step 612, the gNB-CU 602 may perform a communication setup procedure. The gNB-CU 602 may select the dedicated BWP from the list that is indicated as the default BWP received from the gNB-DU 600 in the setup request at step 604, and encode messages specific to the user equipment using the default dedicated BWP.

At step 614, the gNB-CU 602 may send the encoded messages to UE 616.

The default BWP configuration may be based on at least one of a UE service type and a UE category. For example, the gNB-DU 600 may indicate an ID corresponding to a BWP configuration which is a default BWP configuration for a given UE category or a given UE service type. For example, the BWP configuration corresponding to ID = 1 may be the default BWP configuration for a first UE category, and BWP configuration corresponding to ID = 4 may be the default BWP configuration for a second UE category. Reference is made to Figure 7, which shows an example method according to some embodiments.

In the example method of Figure 7, the gNB-DU 700 supports more than one dedicated BWP, but does not indicate a default BWP to the gNB-CU 702.

At step 704, the gNB-DU 700 sends a message comprising cell specific information over the F1 interface to the gNB-CU 702. For example, the message comprising cell specific information may comprise a setup request comprising a list of BWP configurations and a corresponding ID for each BWP configuration.

At step 706, the gNB-CU 702 may store the list of BWP configurations and corresponding IDs.

At step 708, the gNB-CU 702 sends a setup response over the F1 interface to the gNB-DU 700. The setup response may acknowledge receipt of the message comprising cell specific information.

As no default BWP has been indicated by the gNB-DU 700, the gNB-CU 702 may not select a BWP from the list, and instead wait for the gNB-DU 700 to subsequently select a BWP and indicate a BWP ID to the gNB-CU 702.

At step 710, the gNB-CU 702 may receive a message comprising a communication request from the UE 722. In some example embodiments, the message may be received either directly from the UE, or from the UE via an eNB or gNB

At step 712, responsive to the communication request, the gNB-CU 702 may send a further message to the gNB-DU 700. The further message may comprise a UE Context Setup Request, or a UE Context Modification Request. The further message may be specific to a particular user equipment.

At step 714, and in response to receiving the further message sent by the gNB-CU 702 in step 710, the gNB-DU 700 may select a dedicated BWP. Where the further message comprises a UE Context Setup Request, the gNB-DU 700 may select a dedicated BWP from a plurality of dedicated BWPs. Where the further message comprises a UE Context Modification Request, the gNB-DU 700 may select a dedicated BWP from the plurality of BWPs that is different to a currently selected dedicated BWP. At step 716, the gNB-DU 700 may send a further response to the gNB-CU 702. The further response may comprise a UE Context Setup Response or a UE Context Modification Response, and may comprise the ID corresponding to the dedicated BWP selected by the gNB-DU 700 at step 714.

At step 718, the gNB-CU 702 may perform a communication setup procedure. The gNB-CU 702 may select a dedicated BWP from the list received from the gNB-DU 700 in the setup request at step 704 based on the ID indicated in the message received from the gNB-DU 700 at step 716. The gNB-CU 702 may then encode messages specific to the user equipment using the selected dedicated BWP.

At step 720, the gNB-CU 702 may send the encoded messages to UE 722.

Reference is made to Figure 8, which shows a method according to some example embodiments.

At step 804, the gNB-DU 800 sends a message comprising cell specific information over the F1 interface to the gNB-CU 802. For example, the message comprising cell specific information may comprise a setup request comprising a list of BWP configurations and a corresponding ID for each BWP configuration.

At step 806, the gNB-CU 802 may store the list of BWP configurations and corresponding IDs.

At step 808, the gNB-CU 802 sends a setup response over the F1 interface to the gNB-DU 800. The setup response may acknowledge receipt of the message comprising cell specific information.

At step 810, the gNB-DU 800 may determine a change in BWP configuration(s) supported by the gNB-DU 800.

At step 812, the gNB-DU 800 may transmit a further message to the gNB-CU 802. The further message may comprise a BWP configuration update, indicating the change in BWP configuration supported by the gNB-DU 800.

At step 814, the gNB-CU 802 may update the list of BWP configurations based on the further message sent by the gNB-DU 800 at step 812. Having updated the list, at step 816 the gNB-CU 802 may send a further response message to the gNB-DU 800 indicating that the list of BWP configurations stored at the gNB-CU 802 has been updated.

It should be understood that the method described with reference to Figure 8 may be combined with any of the previously described methods. Thus, for example, if the gNB-DU determines a change in supported BWP configuration during any of the previously described methods, the gNB-DU may perform the method described with reference to Figure 8 in order to update the list of configurations at the gNB-CU.

Reference is made to Figure 9, which shows a method according to some example embodiments.

In some example embodiments, a gNB-CU 904 may be in communication with two or more gNB-DUs. For example, the gNB-CU may be in communication with a first gNB-DU 900 and a second gNB-DU 902.

Each of the first and second gNB-DUs 900, 902 may perform a setup procedure as described previously with reference to Figure 4. However, in some example implementations, the list of BWP configurations supported by the first gNB-DU may be different to the list of BWP configurations supported by the second gNB-DU.

Thus, at step 906a and 906b, the first and second gNB-DUs 900, 902 send a message comprising cell specific information over the F1 interface to the gNB-CU 904. The message comprising cell specific information may comprise a setup request comprising a list of BWP configurations and a corresponding ID for each BWP configuration supported by the gNB-DU that sends the message.

At step 908, the gNB-CU 904 may store the list of BWP configurations and corresponding IDs for both gNB-DUs 900, 902.

At step 910a and 910b, the gNB-CU 904 sends a setup response over the F1 interface to the gNB-DUs 900, 902. The setup response may acknowledge receipt of the message comprising cell specific information.

Initially, the UE 918 may be in communication with the gNB via the first gNB-DU 900, using any of the previously described methods, the steps of which are not shown in Figure 9. The UE may then be handed over from the first gNB-DU 900 to the second gNB-DU 902.

At step 912, the gNB-CU 904 may determine that the UE is to be handed over, is being handed over, or has been handed over, from the first gNB-DU 900 to the second gNB-DU 902.

At step 914, the gNB-CU 904 may perform a communication setup procedure by selecting a BWP from the list that is supported by gNB-DU2 902, and encode messages specific to the UE using the selected dedicated BWP. gNB-CU 904 may thus encode user equipment specific messages for transmission to the UE using a BWP configuration supported by the second gNB-DU 902 in response to determining handover of the UE from the first gNB-DU 900 to the second gNB-DU 902. That is to say, the user equipment specific message may be based on one or more BWP configurations for the second gNB-DU.

At step 916, the gNB-CU 904 may send the encoded messages to the UE.

Reference has been made above to the gNB-CU receiving a communication request, and transmitting an encoded message to the UE.

In some example embodiments, such as but not limited to Stand Alone operation, the communication request may comprise an RRC Setup Request, and the encoded message may comprise an RRC Setup Response or RRC Reconfiguration Response. In some example embodiments, the communication request may be sent from a UE to the gNB-CU, and the encoded message may be sent from the gNB-CU to the eNB.

In some example embodiments, such as but not limited to EUTRA-NR Dual Connectivity, the communication request may comprise an X2 access protocol (AP) SgNB Addition Request, and the encoded message may comprise an X2AP SgNB Addition Request Acknowledgement.

In some example embodiments, such as but not limited to NR Dual Connectivity, the communication request may comprise an XnAP S-Node Addition Request, and the encoded message may comprise an XnAP S-Node Addition Request Acknowledgement.

In some cases, for example where the gNB-CU selects a dedicated BWP for a UE based on a default dedicated BWP indicated by the gNB-DU, and the gNB-DU subsequently determines that a different dedicated BWP is to be assigned to the UE, the gNB-DU may select a new dedicated BWP and send a message comprising the ID of the new dedicated BWP to the gNB- CU.

In some example embodiments, the list of BWP configurations comprises a list of downlink and/or uplink BWP. The list may be comprised in a Serving Cell List IE. An example set of lEs for the setup request is provided below:

In some example embodiments, a Selected-BWP-lndex IE may be added to the gNB-CU. An example Selected-BWP-lndex IE is as follows:

In some example embodiments, the User Context Setup Response and/or User Context Modification Response may comprise a gNB-DU to gNB-CU RRC Container. The RRC Container may be split in to two parts.

A first part may comprise a ServingCellConfig IE, which excludes the BWP configuration. This information may be specific to the serving cell, but not the UE. A second part may comprise a ServingCellConfig index to be added or released. This information may be specific to the UE. The gNB-CU may concatenate the first part and the second part to create a CellGroupConfig IE. Example lEs are shown below:

An exemplary Cell Group Config IE according to some embodiments is shown below:

CellGroupConfig ::= SEQUENCE { cellGroupId CellGroupId, rlc-BearerToAddModList SEQUENCE

(SIZE(1..maxLC-ID)) OF RLC-BearerConfig OPTIONAL,

— Need N rlc-BearerToReleaseList SEQUENCE

(SIZE (1..maxLC-ID)) OF LogicalChannelldentity OPTIONAL,

-- Need N mac-CellGroupConfig MAC-CellGroupConfig OPTIONAL, — Need M physicalCellGroupConfig PhysicalCellGroupConfig OPTIONAL, — Need M spCellConfig-Parti SpCellConfig OPTIONAL, — Need M spCellConfig·"Part2 BWPConfig

OPTIONAL, — Need M sCellToAddModList SEQUENCE (SIZE (1..maxNrofSCells)) OF SCellConfig OPTIONAL,

Need N sCellToReleaseList SEQUENCE (SIZE (1..maxNrofSCells)) OF SCelllndex OPTIONAL,

Need N

[ [ reportUplinkTxDirectCurrent-vl530 ENUMERATED {true} OPTIONAL — Cond BWP-Reconfig

] ]

}

While the foregoing description has been provided with reference to a gNB-DU and a gNB- CU, it should be understood that any logical node(s) or node(s) suitable for performing the abovementioned method may be used. That is to say, for example, a first node that performs the same functions as the gNB-DU may be used, and a second node that performs the same functions as the gNB-CU may be used. In some example embodiments, a first node, or distributed unit, and a second node, or central unit, may be used to perform the methods described previously. In some example embodiments, the first and second node may be comprised in the same physical apparatus - for example, the first and second nodes may be comprised in the same network node such as a gNB.

Furthermore, while the forgoing description has been provided with reference to a BWP configuration, it should be understood that the methods may also be applied to other Information Elements relating to a Serving Cell that are at cell-level but configured per UE - for example, the CSI-MeasConfig IE.

This may ensure that only UE-specific aspects are handled during UE-dedicated procedures, and Serving Cell Configurations common to all UEs are handled in non-UE associated procedures like the F1 setup procedure described with reference to Figure 4, and gNB-CU/DU Configuration Update procedures. In some example embodiments, there is provided an apparatus comprising means for transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

In some example embodiments, there is provided an apparatus comprising means for receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based in the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

In some example embodiments, there is provided an apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: transmit, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

In some example embodiments, there is provided an apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receive, at the second node, a connection request message from a user equipment; encode a user equipment specific message for transmission to the user equipment based in the cell specific information comprising the one or more serving cell configurations; and transmit the encoded message to the user equipment in a response to the connection request message

It should be understood that the apparatuses may comprise or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and/or reception. Although the apparatuses have been described as one entity, different modules and memory may be implemented in one or more physical or logical entities. It is noted that whilst some embodiments have been described in relation to 5G networks, similar principles can be applied in relation to other networks and communication systems. Therefore, although certain embodiments were described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.

It is also noted herein 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.

In general, the various embodiments may be implemented in hardware or special purpose circuitry, software, logic or any combination thereof. Some aspects of the disclosure 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 the disclosure is not limited thereto. While various aspects of the disclosure 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.

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 analog and/or digital circuitry) and

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

(i) a combination of analog 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 a mobile phone or server, to perform various functions) 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 and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

The embodiments of this disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and/or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computer- executable components which, when the program is run, are configured to carry out embodiments. The one or more computer-executable components may be at least one software code or portions of it.

Further in this regard it should be noted that any blocks of the logic flow as in the Figures 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 physical media is a non-transitory media.

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 comprise one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples.

Embodiments of the disclosure may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate. The scope of protection sought for various embodiments of the disclosure is set out by the independent claims. The embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the disclosure.

The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiment of this disclosure. 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 of this disclosure will still fall within the scope of this invention as defined in the appended claims. Indeed, there is a further embodiment comprising a combination of one or more embodiments with any of the other embodiments previously discussed.

Claims

1. An apparatus comprising means for: transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

2. The apparatus of claim 1, wherein the message comprising cell specific information comprising the one or more serving cell configurations comprises a single serving cell configuration.

3. The apparatus of claim 1, wherein the message comprising the one or more serving cell configurations comprises a plurality of serving cell configurations and an identifier of a default serving cell configuration comprised in the plurality of serving cell configurations.

4. The apparatus of claim 3, wherein the default serving cell configuration is based on at least one of a user equipment service type and a user equipment category.

5. The apparatus of claim 1 , wherein the means is for: receiving, at the first node from the second node, a first further message comprising at least one of an indication of a user equipment resource request and a user equipment capability; selecting one of the one or more serving cell configurations based on the first further message; and transmitting, from the first node to the second node, a first further response message comprising an indication of an identifier corresponding to the selected one of the one or more serving cell configurations.

6. The apparatus of claim 5, wherein the first further message is a user equipment context setup request or a user equipment context modification request.

7. The apparatus of any preceding claim, wherein the means is for: determining, at the first node, a change in cell configuration supported by the first node; transmitting, from the first node to the second node, a second further message comprising cell specific information based on the determined change in cell configuration supported by the first node; and receiving, at the first node from the second node, a second further response message acknowledging receipt of the further message comprising cell specific information.

8. An apparatus comprising means for: receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

9. The apparatus of claim 8, wherein the message comprising cell specific information comprising the one or more serving cell configurations comprises a single serving cell configuration.

10. The apparatus of claim 9, wherein encoding the user equipment specific message for transmission to the user equipment is based on the single serving cell configuration.

11. The apparatus of claim 8, wherein the message comprising cell specific information comprising the one or more serving cell configurations comprises a plurality of serving cell configurations and an identifier of a default serving cell configuration comprised in the plurality of serving cell configurations.

12. The apparatus of claim 11 , wherein encoding the user equipment specific message for transmission to the user equipment is based on the serving cell configuration corresponding to the received identifier of the default serving cell configuration.

13. The apparatus of any of claims 8 to 12, wherein the means is for: transmitting, from the second node to the first node, a first further user equipment specific message comprising at least one of an indication of a user equipment resource request and a user equipment capability; and receiving, at the second node from the first node, a first further response message comprising an indication of an identifier corresponding to a selected one of the one or more serving cell configurations.

14. The apparatus of claim 13, wherein encoding the user equipment specific message for transmission to the user equipment is based on the serving cell configuration corresponding to the received identifier of the selected serving cell configuration.

15. The apparatus of claims 13 or 14, wherein the first further user equipment specific message is a user equipment context setup request or a user equipment context modification request.

16. The apparatus of any of claims 8 to 15, wherein the means is for determining, by the second node, a number of serving cell configurations supported by the first node.

17. The apparatus of any of claims 8 to 16, wherein the means is for: receiving, at the second node from the first node, a second further message comprising cell specific information based on a determined change in cell configuration supported by the first node; and updating the cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations based on the received second further message.

18. The apparatus of any of claims 8 to 17, wherein the means is for: receiving at second node, from a further first node, a third further message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations for the further first node; determining at the second node that the user equipment is handed over from the first node to the further node; and encoding the user equipment specific message for transmission to the user equipment based on one of the new one or more serving cell configurations supported by the further first node.

19. The apparatus of any preceding claim, wherein the serving cell configuration comprises a bandwidth part configuration.

20. The apparatus of claim 19, wherein the bandwidth part configuration comprises at least one of an uplink bandwidth part configuration and a downlink bandwidth part configuration.

21. The apparatus of any preceding claim, wherein the first node comprises a distributed unit and the second node comprises a central unit.

22. An apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: transmit, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

23. An apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receive, at the second node, a connection request message from a user equipment; encode a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmit the encoded message to the user equipment in a response to the connection request message.

24. A method comprising: transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

25. A method comprising: receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

26. A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least: transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

27. A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least: receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.

28. A computer readable medium comprising program instructions for causing an apparatus to perform at least: transmitting, from a first node to a second node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations.

29. A computer readable medium comprising program instructions for causing an apparatus to perform at least: receiving, at a second node from a first node, a message comprising cell specific information comprising one or more serving cell configurations and a corresponding identifier for each of the one or more serving cell configurations; receiving, at the second node, a connection request message from a user equipment; encoding a user equipment specific message for transmission to the user equipment based on the cell specific information comprising the one or more serving cell configurations; and transmitting the encoded message to the user equipment in a response to the connection request message.