Random access technique

Abstract

A random access technique is described. As to one method aspect of the technique, a method (300) performed by a radio device (100; 1600) for transmitting a random access, RA, preamble in a radio access network, RAN (500), comprising: receiving (302), from the RAN (500), a configuration message (802) indicative of conditional RA occasions, ROs (702), that are subject to an activation status; and transmitting (306), to the RAN (500), the RA preamble in at least one of the conditional ROs (702) if the activation status is active.

Description

[0001]Telefonaktiebolaget LM Ericsson (publ) 1 / 47P112168WO01 25 Sep 2025Random Access TechniqueTechnical Field The present disclosure relates to a technique for random access (RA) in a wireless network. More specifically, and without limitation, methods and devices areprovided for transmitting or receiving a RA preamble in a radio access network.Background Up until Release 18, corresponding versions labelled 18.x.y of the 3GPP specification (e.g. according to 3GPP TS 38.331, version 18.3.0) specify that physical RA channel(PRACH) resources semi-statically configured in system information block type 1 (SIB1)may be updated by the radio access network (RAN) via a so-called system information update (SI update) procedure. If the information in the SIB1 as to the RA channel (RACH)configuration changes, an SI update will be signaled, via the paging downlink controlinformation (DCI) short message mechanism, in all paging occasions (POs) for thecurrent cell during a SI modification period to ensure the information is received by allradio devices (i.e., user equipments, UEs) camping on the cell. The actual change takesplace after the SI modification period. These changes of the RACH configuration are relevant for the RAN in order to optimize its power consumption by adapting the RACH configuration, e.g. the RA occasions (ROs), to the actual need for radio devices accessing the RAN.However, whenever the RAN adapts the RO configuration in the SIB1, it has to signal anSI update. Consequently, if the RO adaptation is dynamic and the RO configurationchanges frequently, the SI update signaling leads to a considerable signaling overheadon the physical downlink control channel (PDCCH). And if the SI update indication wouldbe omitted, the radio devices would need to continuously poll the SIB1 contents.SummaryAccordingly, there is a need for a technique that allows dynamic changes of ROavailability. As to a first method aspect, a method performed by a radio device for transmitting a random access preamble in a radio access network is provided. The methodTelefonaktiebolaget LM Ericsson (publ) 2 / 47P112168WO01 25 Sep 2025comprises receiving, from the radio access network, a configuration message indicative of conditional random access occasions (ROs) that are subject to an activation status. The method further comprises transmitting, to the radio access network, the random access preamble in at least one of the conditional ROs if the activation status is active. The first method aspect may be performed by a radio device, e.g., a user equipment (UE).The first method aspect may further comprise any feature and / or any stepdisclosed in the context of below second method aspect, or a feature and / or stepcorresponding thereto, e.g., a radio device counterpart to a network node feature or step. By virtue of the activation status, the RAN may be enabled to adapt the ROs with limited signaling overhead. Some embodiments of the technique may indicate the activations status in a control message that is related to the transmission or reception of the configuration message, e.g. within the same subframe or slot and / or that schedules the configuration message. Accordingly, radio devices switched on or reselecting to a cell of the RAN after a change of the ROs are notified of the currently available ROs. Same or further embodiments of the technique may indicate the activation status in a control message that is not related to the transmission or reception of the configuration message. Accordingly, radio devices already camping on a cell of the RAN are notified of the available ROs with limited signaling overhead and high robustness, i.e. a low probability of misalignment of radio device assumptions on which ROs are available. In particular, at least some embodiments of the technique can indicate to all idle and / or inactive radio devices, both camping on a cell and radio device reselecting to the cell, the currently available ROs with limited signaling overhead and high robustness. Transmitting a random access preamble (RAP) may equally be referred to as performing (for example, initiating) a random access procedure.Telefonaktiebolaget LM Ericsson (publ) 3 / 47P112168WO01 25 Sep 2025Subject to an activation status may mean that the conditional ROs are available or scheduled in the radio access network for (for example, at least) the radio device for transmitting the random access preamble if (for example, only if) the activation status is active. For example, if the activation status of the conditional ROs is not active (for example, inactive or invalid), the radio device may refrain from transmitting the random access preamble in the conditional ROs. Random access occasions in the radio access network may encompass specific time and / or frequency and / or spatial resources during which a radio device can transmit a random access preamble to initiate the random access procedure. Conventional random access occasions may be scheduled by the radio access network without further condition (for example, as a base set of resources forrandom access) and – according to the above configuration message – with anactivation condition, that is, the requirement that the activation status is set to active prior to or while using the conditional ROs. The conditional ROs may also be referred to as additional ROs (for example, in addition to unconditional ROs). In contrast to conventional (that is, unconditional) ROs, the conditional ROs may be deemed to be not scheduled (for example, not available for transmission) unless or until the activation status is active, for example by receiving further control signaling that is indicative of an activation of the conditional ROs. The radio access network may schedule the conditional ROs according to the above configuration message responsive to an increase in a number of radio devices connected to the radio access network (for example, in one cell of the radio access network) or responsive to a shortage of available ROs. By configuring the radio device, according to the configuration message, with conditional ROs, embodiments of the technique can enable the radio access network to control a number or a density of ROs available to radio devices, such as the radio device performing the method. The radio access network can be enabled to control the number or density of ROs with negligible signaling overhead and / or reduced latency, for example, as the scheduling information (that is, the identification of radio resources) for the conditional ROs is the major part of the configuration and provided once to the radio device in the configuration message. Alternatively or additionally, same or further embodiments of the technique can enable the radio access network to balance its power consumption (for example, associated with monitoring the activated conditional RO for random access preambles as opposed to deactivating a receiver amplifier when the activationTelefonaktiebolaget LM Ericsson (publ) 4 / 47P112168WO01 25 Sep 2025status of the conditional ROs is not active) with an access latency for radio devices or a number of radio devices active (for example, connected to) or accessing the radio access network. The radio access network may control a total number or density of ROs (for example, including conventional unconditional ROs and the conditional ROs) in one cell or in one beam of the radio access network. For example, the configuration message may be cell-specific or beam-specific. The activation status may provide a control mechanism for rapidly and efficiently controlling the number or density of ROs. Embodiments of the technique can enable the radio access network to control the number or density of ROs at a time scale (for example, in terms of latency) that is faster (for example, multiple times shorter) than a time scale (for example, in terms of a transmission periodicity) at which the configuration message is provided. The configuration message may be or may comprise a system information block type 1 (SIB1). The configuration message may be a broadcast or groupcast message of the radio access network, for example, within a cell or a beam of the radio access network. The configuration message may be or may comprise a master information block (MIB) and / or a system information block (SIB), for example a SIB type 1 (SIB1) or a SIB type x (SIBx) for x = 1, 2, 3, …, and / or an energy saving SIB and / or an SIB dedicated for configuring the conditional ROs. For example, the configuration message may comprise MIB or a SIB, for example SIB type 1 (SIB1). The configuration message may comprise any broadcast signal according to a 3GPP specification, for example for a fourth generation (4G) of radio access technology (RAT) (for example, LTE), or for a 5G RAT (for example, NR), or for a 6G RAT. The method may further comprise receiving, from the radio access network, a control message indicative of the activation status of the conditional ROs. At least one of the configuration message and the control message may be indicative of a validity duration for a validity timer. The method may further comprise receiving, from the radio access network, a control message. The control message may be indicative of the activation status of the conditional ROs, optionally for a predefined validity duration, for example starting from the reception of the control message. Alternatively or additionally, the control message may be indicative of whether or not the activation status ofTelefonaktiebolaget LM Ericsson (publ) 5 / 47P112168WO01 25 Sep 2025the conditional ROs is active, optionally for a predefined validity duration starting from the reception of the control message. Alternatively or additionally, the control message may be indicative of whether the conditional ROs are activated or deactivated for the random access, optionally for a predefined validity duration starting from the reception of the control message. The control message may be indicative of the activation status of the conditional ROs being either active or inactive. The activation status for the conditional ROs may be active (that is, set to activated) if the activation status is “on”. The activation status for the conditional ROs may be inactive (that is, not active or set to inactive) if the activation status is “off”. The activation status may be active upon receiving a control message indicative of an activation of the conditional ROs, optionally for a predefined validity duration starting from the reception of the control message. Alternatively or additionally, the activation status may be active if a validity timer initiated upon reception of the configuration message is running. The control message may be the aforementioned control message. Alternatively or additionally, the control message may be received at the radio device and / or from the radio access network. The control message may be the first event to activate the conditional ROs (for example, wherein the conditional ROs are deemed to be deactivated upon receiving the configuration message indicative of the conditional ROs). Alternatively, the conditional ROs may be initially activated (for example, by default or in the absence of a control message indicating deactivation). The control message may be the first event to deactivate the conditional ROs. Alternatively or additionally, the radio device may receive a sequence of control messages each indicating (for example, alternating) the activation status of the conditional ROs. Herein, running may mean not expired or within a validity duration of the validity timer. According to the second option, the validity timer may be the sole controlling element (optionally without DCI or another control message) for activating or deactivating the conditional ROs. The control message may be downlink control information (DCI). For example, the control message may be at least one of a physical layer message, downlink control information (DCI), a medium access control (MAC) layer message, and a MAC control element (MAC CE).Telefonaktiebolaget LM Ericsson (publ) 6 / 47P112168WO01 25 Sep 2025The control message may comprise an indicator that is indicative of an activation status of the conditional ROs. For example, the indicator may be a flag or a bit field comprising one or more bits. The activation status may comprise or indicate that the conditional ROs are either activated or deactivated for a random access in the radio access network. The activation status may be “on” for indicating the fulfilment of an activation condition at the radio access network and / or the availability of the conditional ROs in the radio access network. Alternatively, the activation status may be “off” for indicating that the activation condition is not fulfilled at the radio access network or that the conditional ROs are not available in the radio access network (for example, not monitored by the radio access network). The control message may comprise scheduling information for a downlink reception from the radio access network. Alternatively or additionally, the control message may comprise scheduling information for radio resources other than the conditional ROs. Alternatively or additionally, the control message may comprise scheduling information for a groupcast or broadcast message in the downlink of the radio access network, for example within a cell or a beam of the radio access network. Alternatively or additionally, the control message may comprise scheduling information for a physical downlink shared channel (PDSCH) of the radio access network. Alternatively or additionally, the scheduling information in the control message may be a scheduling assignment unrelated to or independent of the conditional ROs. A format of the control message may be DCI format 1_0. The control message may further be indicative of scheduling information for a paging message in the radio access network and / or the control message may be a paging DCI. The control message may further be indicative of scheduling information for radio resources other than the conditional ROs and / or the control message may further be indicative of scheduling information for a paging early indication (PEI) in the radio access network. In an embodiment, the control message is not indicative of scheduling information for the conditional ROs. Alternatively, the configuration message is indicative of scheduling information for the conditional ROs. A cyclic redundancy check (CRC) of the control message may be scrambled with a radio network temporary identifier (RNTI) for paging (P-RNTI). The control messageTelefonaktiebolaget LM Ericsson (publ) 7 / 47P112168WO01 25 Sep 2025may be broadcast or groupcast in the radio access network, for example within a cell or a beam of the radio access network. Alternatively or additionally, a cyclic redundancy check (CRC) of the control message may be scrambled with a radio network temporary identifier (RNTI) for system information (SI-RNTI) or for paging (P-RNTI) or for paging early indication (PEI-RNTI). The DCI may be scrambled with an RNTI (for example, according to 3GPP document TS 38.212, version 18.4.0) that is not specific for the radio device (for example, not UE-specific such as C-RNTI used for user-specific data or control information). The control message may further be indicative of scheduling information for the reception of the configuration message. For example, the control message is a DCI scheduling the configuration message. The same DCI that is scheduling the configuration message may also be indicative of the activation status (for example, activation or deactivation of the conditional ROs, that is, the activation status being active or inactive, respectively). This can enable immediate usage of the conditional ROs as additional ROs for the random access in the radio access network. The control message may be a DCI for a paging message. The control message may be a DCI for a paging message or a paging early indication in a paging occasion (PO). For example, the activation status indicated by the DCI may be PO-specific. Multiple control messages may be received. Each control message may set (for example, update or alter) the activation status, optionally without changing a configuration of the conditional ROs. The activation status indicated by a control message received after a previous reception of a control message indicating a previous activation status may overrule the previous activation status. Herein, the configuration of the conditional ROs may refer to the time and / or frequency and / or spatial resources of the conditional ROs. Multiple configuration messages may be received. Each configuration message may set (for example, update or alter), a configuration of the conditional ROs, optionally without changing the activation status of the conditional ROs. The configuration message may be indicative of a plurality of conditional ROs, for example periodic ROs. Alternatively or additionally, the transmitting of the random access preamble may comprise selecting one or at least one of the conditional ROs for which the activation status is active.Telefonaktiebolaget LM Ericsson (publ) 8 / 47P112168WO01 25 Sep 2025The radio device may be in an idle mode or an inactive mode with respect to the radio access network. As to a second method aspect, a method performed by a network node for receiving a random access preamble in a radio access network is provided. The method comprises broadcasting or groupcasting, to radio devices, a configuration message indicative of conditional random access occasions (ROs) that are subject to an activation status. The method further comprises receiving, from at least one of the radio devices, the random access preamble in at least one of the conditional ROs if the activation status is active. The broadcasting or groupcasting may be collectively referred to as transmitting. The configuration message may be a broadcast or groupcast message of the network node, for example within a cell or a beam of the network node. The second method aspect may be performed by a network node, e.g., a base station (e.g., eNodeB or gNodeB) or at least a distributed unit (DU) of the base station.The second method aspect may further comprise any feature and / or any stepdisclosed in the context of the first method aspect, or a feature and / or stepcorresponding thereto, e.g., a network counterpart to a radio device feature or step. The configuration message may comprise a system information block (SIB), for example a SIB type 1, and / or an energy saving SIB and / or an SIB dedicated for configuring the conditional ROs. The configuration message may be or may comprise a master information block (MIB) and / or a system information block (SIB), for example a SIB type 1 (SIB1), or a SIB type x (SIBx) for x = 1, 2, 3, etc. Alternatively or additionally, the configuration message may be or may comprise an energy saving SIB and / or an SIB dedicated for configuring the conditional ROs. The method may further comprise broadcasting, to the radio devices, or groupcasting, to a subset of the radio devices, a control message indicative of the activation status of the conditional ROs. The activation status indicated by the control message may be valid for a predefined validity duration, for example starting from the transmission of the control message. Alternatively or additionally, the control message may be indicative of whether or not the activation status of the conditional ROs is active, optionally for a predefined validity duration starting from the transmission of the control message.Telefonaktiebolaget LM Ericsson (publ) 9 / 47P112168WO01 25 Sep 2025Alternatively or additionally, the control message may be indicative of whether the conditional ROs are activated or deactivated for the random access, optionally for a predefined validity duration starting from the transmission of the control message. Herein, predefined may encompass configured (for example, by the configuration message or the control message) or specified by a technical standard. The activation status may be active upon transmitting a control message indicative of an activation of the conditional ROs, optionally for a predefined validity duration, for example starting from the transmission of the control message. Alternatively or additionally, the activation status may be active if a validity timer initiated upon transmission of the configuration message is running. The method may further comprise the steps or features of any one of the previous method aspects or any step or feature corresponding thereto. The configuration message and the control message may be transmitted to the radio device (for example, as a first radio device) in a cell. A repetition of the control message and the configuration message may be transmitted to a second radio device upon entering the cell. For example, the control message and the configuration message are transmitted to the second radio device in the same radio slot of the radio access network. The control message may comprise multiple DCIs for a paging message or a paging early indication in multiple paging occasions (POs). Alternatively or additionally, the activation status indicated by the DCIs in different POs may be different. Transmitting different activation statuses in different POs can enable the network node to selectively assign the conditional ROs or to assign different conditional ROs to different groups of radio devices. The technique may be implemented in the context of any radio access technology (RAT), including fifth generation (5G) new radio (NR) or beyond 5G. Any radio device may be a user equipment (UE), e.g., according to a 3GPP specification. The radio device and the RAN may be wirelessly connected in anuplink (UL) and / or a downlink (DL) through a Uu interface. Optionally, a sidelink(SL) may enable a direct radio communication between proximal radio devices,e.g., a remote radio device and a relay radio device, optionally using a PC5 interface.Telefonaktiebolaget LM Ericsson (publ) 10 / 47P112168WO01 25 Sep 2025The radio device and / or the RAN may form, or may be part of, a radio network,e.g., according to the Third Generation Partnership Project (3GPP) or according tothe standard family IEEE 802.11 (Wi-Fi). The first method aspect and the secondmethod aspect may be performed by one or more embodiments of the radiodevice and the RAN (e.g., a base station or any other network node), respectively.The RAN may comprise one or more base stations (e.g., network nodes), e.g.,performing the second method aspect. Alternatively or in addition, the radionetwork may be a vehicular, ad hoc and / or mesh network comprising two or moreradio devices, e.g., acting as the remote radio device and / or the relay radio device,which may perform the first and / or second method aspect. Any of the radio devices may be a 3GPP user equipment (UE) or a Wi-Fi station (STA). The radio device may be a mobile or portable station, a device for machine- type communication (MTC), a device for narrowband Internet of Things (NB-IoT) or a combination thereof. Examples for the UE and the mobile station include a mobile phone, a tablet computer and a self-driving vehicle. Examples for the portable station include a laptop computer and a television set. Examples for the MTC device or the NB-IoT device include robots, sensors and / or actuators, e.g., in manufacturing, automotive communication and home automation. The MTC device or the NB-IoT device may be implemented in a manufacturing plant, household appliances and consumer electronics. Whenever referring to the RAN, the RAN may be implemented by one or morebase stations (e.g., network nodes).The radio device may be wirelessly connected or connectable (e.g., according to a radio resource control, RRC, state or active mode) with at least one base station(e.g., network node) of the RAN. When performing the first method aspect, theradio device may be in an idle or inactive state (at least with respect to a pertinent cell of the RAN). The network node (e.g., a base station) may encompass any station that is configured to provide radio access to any of the radio devices. The base station may be a cell, a transmission and reception point (TRP), a central unit (CU), a distributed unit (DU), a radio access node or an access point (AP). The base station and / or the relay radio device may provide a data link to a host computer providingTelefonaktiebolaget LM Ericsson (publ) 11 / 47P112168WO01 25 Sep 2025user data to the (e.g., remote) radio device or gathering user data from the (e.g., remote) radio device. Examples for the base stations may include a 3G base station or Node B (NB), 4G base station or eNodeB (eNB), a 5G base station or gNodeB (gNB), a Wi-Fi AP and a network controller (e.g., according to Bluetooth, ZigBee or Z-Wave). The RAN may be implemented according to the Global System for Mobile Communications (GSM), the Universal Mobile Telecommunications System (UMTS), 3GPP Long Term Evolution (LTE) and / or 3GPP New Radio (NR). Any aspect of the technique may be implemented on a Physical Layer (PHY), a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a packetdata convergence protocol (PDCP) layer, and / or a Radio Resource Control (RRC)layer of a protocol stack for the radio communication. Herein, referring to a protocol of a layer may also refer to the corresponding layer in the protocol stack. Vice versa, referring to a layer of the protocol stack may also refer to the corresponding protocol of the layer. Any protocol may be implemented according to an embodiment of the disclosed first and / or secondmethod aspect.As to another aspect, a computer program product is provided. The computer program product comprises program code portions for performing any one of the steps of the first and / or second method aspect disclosed herein when the computer program product is executed by one or more computing devices. The computer program product may be stored on a computer-readable recording medium. The computer program product may also be provided for download, e.g., via the radio network, the RAN, the Internet and / or the host computer. Alternatively, or in addition, the method may be encoded in a Field-Programmable Gate Array (FPGA) and / or an Application-Specific Integrated Circuit (ASIC), or the functionality may be provided for download by means of a hardware description language. As to a first device aspect, a radio device for transmitting a random access preamble in a radio access network is provided. The radio device may comprise memory operable to store instructions and processing circuitry operable to execute the instructions, such that the radio device is operable to receive, from the radio access network, a configuration message indicative of conditionalTelefonaktiebolaget LM Ericsson (publ) 12 / 47P112168WO01 25 Sep 2025random access occasions (ROs) that are subject to an activation status, and to transmit, to the radio access network, the random access preamble in at least one of the conditional ROs if the activation status is active. The radio device may further comprise the features and may be operable to perform the steps of any one of the method aspects described above. As to another first device aspect, a radio device for transmitting a random access preamble in a radio access network is provided. The radio device may be configured to receive, from the radio access network, a configuration message indicative of conditional random access occasions (ROs) that are subject to an activation status, and to transmit, to the radio access network, the random access preamble in at least one of the conditional ROs if the activation status is active. The radio device may further comprise the features and may be configured to perform the steps of any one of the method aspects described above. The devicemay be configured to perform any one of the steps of the first method aspect. Asto a further first device aspect, the device comprises processing circuitry (e.g., atleast one processor and a memory). Said memory comprises instructionsexecutable by said at least one processor whereby the radio device is operative toperform any one of the steps of the first method aspect. As to a second device aspect, a network node for receiving a random access preamble in a radio access network is provided. The network node may comprise memory operable to store instructions and processing circuitry operable to execute the instructions, such that the network node is operable to broadcast or groupcast, to radio devices, a configuration message indicative of conditional random access occasions (ROs) that are subject to an activation status, and to receive, from at least one of the radio devices, the random access preamble in at least one of the conditional ROs if the activation status is active. The network node may further comprise the features and may be operable to perform the steps of any one of the method aspects described above. As to another second device aspect, a network node for receiving a random access preamble in a radio access network is provided. The network node may be configured to broadcast or groupcast, to radio devices, a configuration message indicative of conditional random access occasions (ROs) that are subject to an activation status, and to receive, from at least one of the radio devices, theTelefonaktiebolaget LM Ericsson (publ) 13 / 47P112168WO01 25 Sep 2025random access preamble in at least one of the conditional ROs if the activation status is active. The network node may further comprise the features and may be configured to perform the steps of any one of the method aspects described above. The network node may be configured to perform any one of the steps of the second methodaspect. As to a further second device aspect, the network node comprisesprocessing circuitry (e.g., at least one processor and a memory). Said memory comprises instructions executable by said at least one processor whereby thenetwork node is operative to perform any one of the steps of the second methodaspect. As to a system aspect, a communication system including a host computer is provided. The host computer may comprise processing circuitry configured to provide user data, and a communication interface configured to forward the user data to a cellular or ad hoc radio network for transmission to a radio device. The radio device may comprise a radio interface and processing circuitry, the processing circuitry of the radio device being configured to execute the steps of any one of the method aspects described above responsive to a paging message indicating the availability of the user data.As to a still further aspect a communication system comprising at least onenetwork node according to the second device aspect and at least one radio device according to the first device aspect is provided. Alternatively or in addition, the communication system comprises a host computer. The host computer comprises a processing circuitry configured to provide user data, e.g., triggering the random access in the first and / or second method aspect. The host computer furthercomprises a communication interface configured to forward the user data to acellular network (e.g., the RAN and / or the network node of the second deviceaspect) for transmission to a radio device (e.g., UE) according to the first deviceaspect. A processing circuitry of the cellular network may be configured to executeany one of the steps of the second method aspect. Alternatively or in addition, theradio device comprises a radio interface and processing circuitry, which is configured to execute any one of the steps of the first method aspect. The cellular network may further include one or more base stations (e.g., networknodes) configured for radio communication with the radio device (e.g., UE) and / orto provide a data link between the radio device and the host computer using the first and / or second method aspects.Telefonaktiebolaget LM Ericsson (publ) 14 / 47P112168WO01 25 Sep 2025The processing circuitry of the host computer may be configured to execute a hostapplication, thereby providing the user data and / or any host computerfunctionality described herein. Alternatively, or in addition, the processing circuitry of the UE may be configured to execute a client application associated with the host application. Any one of the devices, the radio device, the UE, the base station, the network node, the communication system or any node or station for embodying the technique may further include any feature disclosed in the context of the methodaspect, and vice versa. Particularly, any one of the units and modules disclosedherein may be configured to perform or initiate one or more of the steps of themethod aspect. Brief Description of the Drawings Further details of embodiments of the technique are described with reference to the enclosed drawings, wherein:Fig. 1 shows a schematic block diagram of an embodiment of a device fortransmitting a random access preamble;Fig. 2 shows a schematic block diagram of an embodiment of a device forreceiving a random access preamble;Fig. 3 shows a flowchart for a method of transmitting a random accesspreamble, which method may be implementable by the device of Fig.1;Fig. 4 shows a flowchart for a method of receiving a random access preamble,which method may be implementable by the device of Fig.2;Fig. 5 schematically illustrates an example of a radio network comprisingembodiments of the devices of Figs. 1 and 2 for performing the methodsof Figs. 3 and 4, respectively;Fig. 6 schematically illustrates a first example section of a time domaincomprising 5 radio frames each having one subframe comprising a random access occasion (RO);Telefonaktiebolaget LM Ericsson (publ) 15 / 47P112168WO01 25 Sep 2025Fig. 7 schematically illustrates a second example section of a time domaincomprising 2 radio frames each having one subframe comprising a conditional RO;Fig. 8 schematically illustrates a first example of an event sequencecorresponding to embodiments of the methods of Figs. 3 and 4;Fig. 9 schematically illustrates a second example of an event sequencecorresponding to embodiments of the methods of Figs. 3 and 4;Fig. 10 schematically illustrates an example of the configuration message, whichmay be implemented in any embodiment of the devices of Figs. 1 and 2and the methods of Figs. 3 and 4;Fig. 11 schematically illustrates a third example of an event sequencecorresponding to embodiments of the methods of Figs. 3 and 4;Fig. 12 schematically illustrates a fourth example of an event sequencecorresponding to embodiments of the methods of Figs. 3 and 4;Fig. 13 schematically illustrates a fifth example of an event sequencecorresponding to embodiments of the methods of Figs. 3 and 4;Fig. 14 schematically illustrates a first example of the control message, which maybe implemented in any embodiment of the devices of Figs. 1 and 2 and themethods of Figs. 3 and 4;Fig. 15 schematically illustrates a second example of the control message, whichmay be implemented in any embodiment of the devices of Figs. 1 and 2and the methods of Figs. 3 and 4;Fig. 16 shows a schematic block diagram of a radio device embodying the deviceof Fig. 1;Fig. 17 shows a schematic block diagram of a radio access network embodying thedevice of Fig. 2; andTelefonaktiebolaget LM Ericsson (publ) 16 / 47P112168WO01 25 Sep 2025Fig. 18 schematically illustrates an example telecommunication networkconnected via an intermediate network to a host computer. Detailed Description In the following description, for purposes of explanation and not limitation, specific details are set forth, such as a specific network environment in order to provide a thorough understanding of the technique disclosed herein. It will be apparent to one skilled in the art that the technique may be practiced in other embodiments that depart from these specific details. Moreover, while thefollowing embodiments are primarily described for a New Radio (NR) or 5Gimplementation, it is readily apparent that the technique described herein may also be implemented for any other radio communication technique, including a Wireless Local Area Network (WLAN) implementation according to the standard family IEEE 802.11, 3GPP LTE (e.g., LTE-Advanced or a related radio access technique such as MulteFire), for Bluetooth according to the Bluetooth Special Interest Group (SIG), particularly Bluetooth Low Energy, Bluetooth Mesh Networking and Bluetooth broadcasting, for Z-Wave according to the Z-Wave Alliance or for ZigBee based on IEEE 802.15.4. Moreover, those skilled in the art will appreciate that the functions, steps, units and modules explained herein may be implemented using software functioning in conjunction with a programmed microprocessor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a Digital Signal Processor (DSP) or a general purpose computer, e.g., including an Advanced RISC Machine (ARM). It will also be appreciated that, while the following embodiments are primarily described in context with methods and devices, the invention may also be embodied in a computer program product as well as in a system comprising at least one computer processor and memory coupled to the at least one processor, wherein the memory is encoded with one or more programs that may perform the functions and steps or implement the units and modules disclosed herein.Fig. 1 schematically illustrates a block diagram of an embodiment of a device fortransmitting a random access (RA) preamble (RAP). The device is generically referred to by reference sign 100.Telefonaktiebolaget LM Ericsson (publ) 17 / 47P112168WO01 25 Sep 2025The device 100 comprises a configuration reception module 102 that receives (302), from a RAN (500), a configuration message (802) indicative of conditional RA occasions, ROs (702), that are subject to an activation status. The device 100 further comprises a RA transmission module 106 that transmits (306), to the RAN (500), the RA preamble in at least one of the conditional ROs (702) if the activation status is active.Optionally, the device 100 further comprises a control reception module 104 thatsets the activation status at the device 100 upon receiving (304) a control message (804; 806) indicative of an activation or deactivation of the conditional ROs. Any of the modules of the device 100 may be implemented by units configured to provide the corresponding functionality.The device 100 may also be referred to as, or may be embodied by, the radiodevice. The radio device 100 and the RAN (e.g., a network node of the RAN) maybe in direct radio communication, e.g., at least for the three steps. The RAN maybe embodied by the below device 200. Fig.2 schematically illustrates a block diagram of an embodiment of a device forreceiving a RA preamble. The device is generically referred to by reference sign200.The device 200 comprises a modules 202 and 206, and optionally module 204,mirroring the modules of the device 100. Furthermore, the device 200 may becapable of serving multiple radio device 100, optionally by differentiating groups of radio device 100, to which different sets of conditional ROs are assigned. Any of the modules of the device 200 may be implemented by units configured to provide the corresponding functionality.The device 200 may also be referred to as, or may be embodied by, the RAN (e.g.,a network node of the RAN). The network node 200 and the at least one radio device may be in direct radio communication, e.g., at least for the three steps. The radio device may be embodied by the above-mentioned device 100.Telefonaktiebolaget LM Ericsson (publ) 18 / 47P112168WO01 25 Sep 2025Fig. 3 shows an example flowchart for a method 300 of performing the firstmethod aspect. The method comprises the steps indicated in Fig. 3.The method 300 may be performed by the device 100. For example, the modules102, 104 and 106 may perform the steps 302, 304 and 306, respectively.Fig.4 shows an example flowchart for a method 400 of performing the secondmethod aspect. The method comprises the steps indicated in Fig. 4.The method 400 may be performed by the device 200. For example, the modules 202, 204 and 206 may perform the steps 402, 404 and 406, respectively. In any aspect, the technique may be applied to uplink (UL), downlink (DL) or direct communications between radio devices, e.g., device-to-device (D2D) communications or sidelink (SL) communications.Each of the radio device 100 and network node 200 may be a UE or a base station.Herein, any radio device may be a mobile or portable station and / or any radio device wirelessly connectable to a base station or RAN, or to another radio device.For example, the radio device may be a user equipment (UE), a device formachine-type communication (MTC) or a device for (e.g., narrowband) Internet of Things (IoT). Two or more radio devices may be configured to wirelessly connect toeach other, e.g., in an ad hoc radio network or via a 3GPP SL connection.Furthermore, any base station may be a station providing radio access, may be part of a radio access network (RAN) and / or may be a node connected to the RANfor controlling the radio access. For example, the base station may be an accesspoint, for example a Wi-Fi access point. Furthermore, "predefined" may encompass stored in memory (e.g., in a Subscriber Identity Module, SIM) of the transmitting wireless device, or hard- coded or hard-wired in the transmitting wireless device, or preconfigured or configured by a network node or radio access network (RAN) for the transmitting wireless device (e.g., preconfigured while in coverage prior to performing the method out of coverage, or configured while in coverage when performing the method). Herein, a list of the form A, B, and / or C (also written as A, B and / or C) may correspond to at least one or each of A, B, and C, i.e., A and / or B and / or C.Telefonaktiebolaget LM Ericsson (publ) 19 / 47P112168WO01 25 Sep 2025Embodiments of the technique may relate to a random access channel (RACH) procedure, and / or RACH occasions (ROs), and / or may enable an adaptation of RO provision, optionally for network energy savings (NES). Fig.5 schematically illustrates an example of a radio network including a radio access network 500 comprising embodiments of the radio devices 100 and at least one embodiment of the network node 200 for performing the methods 300 and 400, respectively, optionally within a cell 201 served by the network node 200. A second radio device 100 may be outside of the cell 201 when a change of the conditionally RO occurs. Embodiments of the technique enable the second radio device 100 to be configured with the available ROs including their activation status upon entering the cell 201. Any embodiment of the radio device 100 or the network node 200 may implement at least one of the following features and steps of a RACH procedure. RACH and RA may be understood synonymously. For concreteness and without limitation to a particular 3GPP specification, the radio device is referred to as a UE 100 and the network node is referred to as a gNodeB 200 herein below. RACH resources are configured via higher layers (e.g. system information) andtypical RACH resources may occur periodically as shown in Fig. 6, where each cellcorresponds to a slot or a subframe. After sending a RACH message (RA preamble), the UE monitors for a RACH response in a search space (e.g. ra- searchSpace, that is configured by higher layers), and if it does not receive a response within a pre-determined amount of time, the UE tries to send RACH again.Fig. 6 schematically illustrates uplink resources for random access (e.g., oneRACH occasion in subframe #4 of each radio frame). NR provides 2 types of RACH procedures in terms of contention: contention- based RACH and contention free RACH. Each RACH procedure can be performed by a 4-step RA or 2-step RA. NW decides which type of RA is adopted based on channel statues and latency requirements, and other elements.Telefonaktiebolaget LM Ericsson (publ) 20 / 47P112168WO01 25 Sep 2025A configuration of the 4-step RACH may comprise at least one of the following parameters (represented using Abstract Syntax Notation One, ASN1), which may be configured via broadcast system information block type 1 (SIB1).-- ASN1START-- TAG-RACH-CONFIGCOMMON-STARTRACH-ConfigCommon ::= SEQUENCE { rach-ConfigGeneric RACH-ConfigGeneric, totalNumberOfRA-Preambles INTEGER (1..63)OPTIONAL, -- Need Sssb-perRACH-OccasionAndCB-PreamblesPerSSB CHOICE { oneEighth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64}, oneFourth ENUMERATED{n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64}, oneHalf ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64}, one ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64}, two ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32}, four INTEGER (1..16), eight INTEGER (1..8), sixteen INTEGER (1..4) }OPTIONAL, -- Need MgroupBconfigured SEQUENCE { ra-Msg3SizeGroupA ENUMERATED {b56, b144, b208, b256, b282, b480, b640, b800, b1000, b72, spare6, Telefonaktiebolaget LM Ericsson (publ) 21 / 47P112168WO01 25 Sep 2025}-- TAG-RACH-CONFIGCOMMON-STOP-- ASN1STOPThe parameters of 2-step RACH may be defined as follows, e.g. in a radioresource control (RRC) information element (IE), such as the RACH-ConfigCommonTwoStepRA information element.-- ASN1START-- TAG-RACH-CONFIGCOMMONTWOSTEPRA-START restrictedSetTypeB} OPTIONAL, -- Cond 2StepOnly ra-PrioritizationForAccessIdentityTwoStep-r16 SEQUENCE { ra-Prioritization-r16 RA-Prioritization, ra-PrioritizationForAI-r16 BIT STRING (SIZE (2)) } OPTIONAL, -- Cond InitialBWP-Only ra-ContentionResolutionTimer-r16 ENUMERATED {sf8, sf16, sf24, sf32,sf40, sf48, sf56, sf64} OPTIONAL, -- Cond 2StepOnly..., [[ ra-PrioritizationForSlicingTwoStep-r17 RA-PrioritizationForSlicing-r17OPTIONAL, -- Cond InitialBWP-OnlyfeatureCombinationPreamblesList-r17 SEQUENCE (SIZE(1..maxFeatureCombPreamblesPerRACHResource-r17)) OF FeatureCombinationPreambles-r17OPTIONAL -- Cond AdditionalRACH]] } GroupB-ConfiguredTwoStepRA-r16 ::= SEQUENCE {Telefonaktiebolaget LM Ericsson (publ) 22 / 47P112168WO01 25 Sep 2025ra-MsgA-SizeGroupA-r16 ENUMERATED {b56, b144, b208, b256, b282, b480, b640, b800, b1000, b72, spare6, spare5, spare4, spare3, spare2, spare1}, messagePowerOffsetGroupB-r16 ENUMERATED {minusinfinity, dB0, dB5, dB8, dB10, dB12, dB15, dB18}, numberOfRA-PreamblesGroupA-r16 INTEGER (1..64) }-- TAG-RACH-CONFIGCOMMONTWOSTEPRA-STOP-- ASN1STOPIn this context, SSB refers to a Synchronization Signal Block (i.e., Synchronization / PBCH block, wherein a synchronization signal and a physical broadcast channel (PBCH) are integrated into a single block that is contained together in the time and frequency. Furthermore, this context, CB refers to a contention-based transmission, i.e., a situation wherein multiple UEs can transmit using the same resources without dedicated resource assigned to a specific UE, which means multiple devices might attempt to transmit at the same time, leading to potential collisions. Contention-based random access is one of the methods used by UEs to initiate communication with the network.The technique may provide additional RACH occasions (ROs) as the conditionalROs.Alternatively or in addition, the technique may be implemented in Release 19Network Energy Saving (NES), which introduces dynamic adaptation of RACH occasions. As such additional ROs are provided beyond a baseline ROconfiguration (i.e., the unconditional ROs). This is exemplified in Fig. 7 wherein abaseline configuration is provided in SIB1 according to legacy means (top subfigure). Additional ROs are also configured in SIB1 (mid subfigure) but only intended to be used when indicated by the NW. Bottom subfigure shows the sum of available ROs for the UE where the additional ROs are also activated. Any embodiment may use a downlink control information (DCI) message (briefly:DCI) as an example of the control message. The DCI messages are referred to byreference signs 804 and 806 herein. Alternatively or in addition, the information transmitted in a DCI message 804 of DCI format 1_0 with CRC scrambled by SI-RNTI may be comprise any information indicated 3GPP TS 38.212, version 18.4.0, clauses 7.3.1.1.1 and 7.3.1.2.1 on DCI formats for scheduling of PUSCH or at least one of the following.Telefonaktiebolaget LM Ericsson (publ) 23 / 47P112168WO01 25 Sep 2025- Frequency domain resource assignment – bits- the size of CORESET 0- Time domain resource assignment – 4 bits as defined in Clause 5.1.2.1 of3GPP TS 38.214, e.g. version 19.0.0.- a virtual resource block to physical resource block mapping (VRB-to-PRBmapping) – 1 bit according to Table 7.3.1.2.2-5- Modulation and coding scheme – 5 bits as defined in Clause 5.1.3 of 3GPPTS 38.214, e.g. version 19.0.0, using Table 5.1.3.1-1- Redundancy version – 2 bits as defined in Table 7.3.1.1.1-2- System information indicator – 1 bit as defined in Table 7.3.1.2.1-2Alternatively or in addition, any embodiment of the technique may use at least one of the following reserved bits for indicating the activation status.- Reserved bits – 17 bits for operation in a cell with shared spectrumchannel access in frequency range 1 or for operation in a cell in frequency range 2-2; otherwise 15 bits. Bit field System information indicator0 SIB1 [e.g., 3GPP TS 38.331, Clause 5.2.1]1 SI message [e.g., 3GPP TS 38.331, Clause 5.2.1]Alternatively or in addition, any embodiment may use at least some of the following information transmitted by means of the DCI format 1_0 with CRCscrambled by P-RNTI as an example of the DCI message 806.- Short Messages Indicator - 2 bits according to Table 7.3.1.2.1-1.- Short Messages - 8 bits, according to Clause 6.5 of 3GPP TS 38.331. If onlythe scheduling information for Paging, and TRS availability indication if trs-ResourceSetConfig or trs-ResourceSetConfig-r18 is configured, are carried, this bitfield is reserved.- Frequency domain resource assignment bits. Ifonly the short message, and TRS availability indication if trs-ResourceSetConfig ortrs-ResourceSetConfig-r18 is configured, are carried, this bit field is reserved.- is the size of CORESET 0Telefonaktiebolaget LM Ericsson (publ) 24 / 47P112168WO01 25 Sep 2025- Time domain resource assignment - 4 bits as defined in Clause 5.1.2.1 of3GPP TS 38.214, e.g. version 19.0.0. If only the short message, and TRSavailability indication if trs-ResourceSetConfig or trs-ResourceSetConfig-r18 isconfigured, are carried, this bit field is reserved.- VRB-to-PRB mapping - 1 bit according to Table 7.3.1.2.2-5. If only the shortmessage, and TRS availability indication if trs-ResourceSetConfig or trs-ResourceSetConfig-r18 is configured, are carried, this bit field is reserved.- Modulation and coding scheme - 5 bits as defined in Clause 5.1.3 of 3GPPTS 38.214, e.g. version 19.0.0, using Table 5.1.3.1-1. If only the short message,and TRS availability indication if trs-ResourceSetConfig or trs-ResourceSetConfig-r18 is configured, are carried, this bit field is reserved.- TB scaling - 2 bits as defined in Clause 5.1.3.2 of 3GPP TS 38.214, e.g.version 19.0.0. If only the short message, and TRS availability indication if trs-ResourceSetConfig or trs-ResourceSetConfig-r18 is configured, are carried, this bitfield is reserved.- TRS availability indication - 1, 2, 3, 4, 5, or 6 bits, where the number of bitsis equal to one plus the highest value of all the indBitID(s) provided by the trs-ResourceSetConfig if configured or the number of bits is equal to one plus thehighest value of all the indBitID-r18(s) provided by the trs-ResourceSetConfig-r18 if configured; 0 bits otherwise.- Reserved bits - (8 - M) bits for operation in a cell with shared spectrumchannel access in frequency range 1 or for operation in a cell in frequency range2-2; (6 - M) bits for operation in a cell without shared spectrum channel access,where the value of M is the number of bits for the field of 'TRS availabilityindication' as defined above. DCI format 2_7 is used for notifying the paging early indication (PEI) and TRS availability indication for one or more UEs. The following information is transmitted by means of the DCI format 2_7 with CRC scrambled by PEI-RNTI:- Paging indication field - ^^^^^^^^^^^bit(s), where- ^^^^^^is the number of paging occasions configured by higher layerparameter po-NumPerPEI as defined in Clause 10.4A in 3GPP TS 38.213;- ^^^^^is the number of sub-groups of a paging occasion configured by higher layer parameter subgroupsNumPerPO.- Each bit in the field indicates one UE subgroup of a paging occasion.- TRS availability indication - 1, 2, 3, 4, 5, or 6 bits, where the number of bitsis equal to one plus the highest value of all the indBitID(s) provided by the trs-ResourceSetConfig or the number of bits is equal to one plus the highest value ofTelefonaktiebolaget LM Ericsson (publ) 25 / 47P112168WO01 25 Sep 2025all the indBitID-r18(s) provided by the trs-ResourceSetConfig-r18 if configured ifconfigured; 0 bits otherwise. The size of DCI format 2_7 is indicated by the higher layer parameterpayloadSizeDCI-2-7, according to Clause 10.4A of 3GPP TS 38.213. The number ofinformation bits in format 2_7 shall be equal to or less than the payload size of format 2_7. If the number of information bits in format 2_7 is less than the size of format 2_7, the remaining bits are reserved. Any embodiment may use at least one of the above-mentioned reserved bits to indicate the activation status. These or further embodiments can address at least one of the followingproblems of the prior art.When the UE 100 loses synchronization with the serving cell in the uplinkdirection (due to mobility or timing issues), it needs to re-establish uplink synchronization using the random access (RA) procedure. This happens, e.g., when the UE’s Timing Advance (TA) becomes invalid or when a certain TA timer expires. In an exemplary scenario, as the UE 100 moves further away from the base station 200 (e.g., gNB), it may experience uplink timing misalignment, requiring a random access (RA) procedure to correct this. When additional RA occasions (ROs) are activated or deactivated by the NW, UEs 100 in the RRC_CONNECTED mode may be informed via dedicated RRC signaling. However, UEs that are in an idle state (e.g., RRC_IDLE) or in an inactive state (e.g., RRC_INACTIVE) conventionally need to receive the relevant indications via system broadcast signaling. When a UE in RRC_IDLE mode has uplink data to send or when the network requests the UE to transition to RRC_CONNECTED (e.g., for incoming downlink data or response to network paging), the UE must perform a random access procedure to establish or resume its connection with the network. In an exemplary scenario, the UE has uplink data (like a phone call, message, or internet data) or has received a paging request for downlink data and needs to switch to RRC_CONNECTED mode. It initiates random access to request resources from the network. A straightforward extension of the legacy RO approach would be to indicate the additional RO configuration, together with its current ON / OFF status, in the SIB1, or another SIB, and signal a SI update whenever the status changes. However, ifTelefonaktiebolaget LM Ericsson (publ) 26 / 47P112168WO01 25 Sep 2025the RO adaptation is dynamic and the state changes frequently, the SI update signaling may lead to a considerable PDCCH signaling overhead. If the SI update indication would be omitted, the UEs would need to continuously poll the SIBx contents. On the other hand, if the dynamic indication is done via a separate indication, such as a DCI, a UE entering the cell after the indication will not know about the additional resources until a new set of indications are transmitted by the NW.Embodiments of the technique provide a method that allows dynamic indicationof additional RO availability to all idle and / or inactive UEs 100 both camping on acell and UEs reselecting to the cell after the indication, with limited signaling overhead and high robustness, i.e. a low probability of misalignment of UE assumptions on which ROs are available. An independent aspect performed by corresponding methods at the UE 100 and the network node 200 provides solutions for signaling from the RAN 500 to the UE 100 for providing additional RO configuration information (i.e., aconfiguration of the conditional ROs) and indicating the current availability (i.e.,the activation status being an ON or OFF status) of the additional ROs 702.In an embodiment, the signaling includes a combination of SIBx payload as the configuration message 802 (for the SIB type x being 1, 2, 3 etc.) and its accompanied DCI signaling 804, and / or in addition to a separate DCI signaling 806, without having negative impact on an energy consumption of the UE 100 (i.e., no extra wakeups for the sake of receiving the extra signaling).As such, both UEs 100 already in the cell 201 and new UEs 100 entering the cell201 will be made aware of the additional available ROs 702.The SIBx may be SIB1 or another SIB, e.g., an energy savings SIB or a new dedicated SIB for additional common signal adaptation support. The DCI may be one or more of: the SIBx scheduling DCI and the paging DCI. The SIBx 802 and / or DCI signaling 804 and / or 806 may include validity timer signaling, where the validity timer value 1202 or 1204 may contain the totalduration 1202 or the remaining duration 1204 of the additional RO availability.Telefonaktiebolaget LM Ericsson (publ) 27 / 47P112168WO01 25 Sep 2025In any embodiment, a synchronization signal block (SSB) may enable the radiodevice 100 (e.g., a user equipment, UE) to monitor a physical downlink control channel (PDCCH) for downlink control information (DCI), which schedules the system information blocks (SIBs), e.g. SIB1, SIB2, SIB3, etc., any one of which may be referred to as SIBx herein.The SSB may comprise a primary synchronization signal (PSS) and a secondarysynchronization signal (SSS), which allow the radio device to achieve initial timeand frequency synchronization in the downlink with a cell of the RAN.Furthermore, by decoding the SSS, the radio device 100 may determine a cellidentity of the cell and a timing of the radio frame.The MIB may be carried by a physical broadcast channel (PBCH), e.g. as is part ofthe SSB. The MIB may contain minimal system information required for the radio device to initially access a cell, such as the system frame number (SFN), subcarrier spacing (SCS), and / or information about a control resource set 0 (CORESET0). The CORESET0 may define a configuration of the PDCCH for scheduling initial system information (SIBx). The DCI, which is scheduling the SIBx, may comprise a cyclic redundancy check (CRC) value that is scrambled by a radio network temporary identifier for system information (SI-RNTI). Optionally, the SI-RNTI is not explicitly signaled to the radio device but is part of a (e.g., 5G NR or 6G) specification of a radio accesstechnology used by the RAN 500. Alternatively or in addition, the SI-RNTI may bea globally fixed value, e.g. defined in 3GPP specifications, optionally in 3GPP document TS 38.321, version 18.3.0, and / or 3GPP document TS 38.331, version 18.3.0.The DCI 804 scheduling the SIBx 802 may be indicative of the exact time andfrequency resources, e.g. on a physical downlink shared channel (PDSCH), onwhich the SIBx is transmitted. That is scheduling information for the SIBx 802. Bydecoding the DCI 804 with the SI-RNTI, the radio device 100 may receive thescheduling information for the SIBx 802. Based on the scheduling information,the radio device 100 may receive the SIBx 802 from the PDSCH. The SIB1802 may contain more detailed information such as cell access-relatedparameters, scheduling of other SIBs 802, and / or network configuration.Telefonaktiebolaget LM Ericsson (publ) 28 / 47P112168WO01 25 Sep 2025Independent or in addition to the above embodiments and the list of embodiments, the first method aspect may comprise a method 300 in a UE 100 for additional RO utilization. The method 300 comprises receiving 302 a firstmessage 802, comprising one or more additional RO configurations, e.g., whereinthe first message 802 is provided via a first SIBx payload component.In a step 304, one or both of a second message 804 and a third message 806 isreceived, which messages 804 and / or 806 are referred to as control message and comprising an additional RO availability indication. For example, the second message 804 may comprises additional RO status (ON / OFF) information and is provided via a second SIBx payload component or a first DCI transmission. Alternatively or in addition, the third message 806 may comprise additional ROstatus change (from ON to OFF or vice versa) information and is provided via asecond DCI transmission.In a step 306, the UE 100 may perform a RACH procedure based on the additionalRO configuration, if the additional RO availability indication signals ON-status, or based on the legacy RO configuration if the additional RO availability indication signals OFF-status. Optionally, the additional RO configuration is associated with at least of 2-step RACH, 4-step RACH, IAB-MT RACH and RACH for slicing. Alternatively or in addition, the first message 802 or the second message 804may comprise an additional RO validity timer. In a first variant, the validity timerindicates a minimum guaranteed availability duration after an availabilityindication is received. In a second variant, which may be combined with the firstvariant, the validity timer may indicate a total availability time fromcorresponding activation. In a third variant, which may be combined with the firstand / or second variant, the validity timer indicates a remaining availability time.Alternatively or in addition, the first DCI transmission 804 is an SIBx-schedulingDCI. In a first variant, the UE 100 may assume the indicated additional RO statusimmediately from the reception instance of the first DCI transmission. In asecond variant, which may be combined with the first variant, the additional ROTelefonaktiebolaget LM Ericsson (publ) 29 / 47P112168WO01 25 Sep 2025validity timer 1204 of the first message 802 or the second message 804 isrefreshed by the second DCI transmission 806. In a third variant, which may becombined with the first and / or second variant, another SIBx 802 after the firstDCI 804 compensate their timer offset corresponding to the second DCI 806.Alternatively or in addition, the second DCI transmission 806 may be a paging DCItransmission. In a first variant, a short message or a (e.g., previously reserved) bitvalue in the paging DCI indicates an additional RO status change. Optionally, theUE 100 may assume the indicated additional RO status starting from the nextSIBx transmission after the second DCI transmission. Alternatively or in addition,the UE 100 may assume the indicated additional RO status immediately from thereception instance of the second DCI transmission. In a second variant, whichmay be combined with the first variant, a short message in the paging DCI indicates SI update. Alternatively or in addition, the second DCI transmission 806 is a paging earlyindication (PEI) DCI transmission. In a variant, a (e.g., previously reserved) bitvalue in the PEI DCI indicates an additional RO status change. Alternatively or in addition, the SIBx 802 is SIB1 or another SIBn. Alternatively or in addition, the first DCI 804 and / or the second DCI 806 further include information on whether the use of additional ROs are for one or more of RRC_IDLE, or RRC_INACTIVE, or RRC CONNECTED mode operation. Alternatively or in addition, the first DCI 804 and / or the second DCI 806 further include information on whether the UEs 100 are allowed to use both (e.g., aunion or any of) the legacy (i.e., unconditional) ROs and the additional (i.e.,conditional) ROs. Any of the above embodiments and the embodiments in the list of embodiments may further comprise at least one of the features of the following detailed embodiments. Using only prior art technical specifications, configurations provided to RRC-idleand / or RRC-inactive UEs are provided via System Information (SI). As such, theadditional RO configuration described above is provided in one of the system information blocks SIBx. In addition to the additional RO configuration, the gNBTelefonaktiebolaget LM Ericsson (publ) 30 / 47P112168WO01 25 Sep 2025needs to also control whether said configuration is currently activated or deactivated, i.e., UEs need to be made aware of the status (called RoCfgStatus hereafter) of the configuration. One way to convey the RoCfgStatus to the UEs in RRC Idle / Inactive would be to also provide the status as part of SIBx, however this would not be an optimal way of informing the UEs. As mentioned earlier, content of a SIBx cannot be changed at any point in time but is subject to SI modification period boundaries. A typical example of such period is 5.12 seconds. Therefore, incorporating RoCfgStatus into SIBx would lead to a slow update mechanism. Instead, a typical workaround would be to separate the RoCfgStatus indication into its own message, such as a DCI which is not bound to any modification period. Such a scheme is exemplified below where a DCI is used toupdate the UEs of the cell (UE1) regarding the RoCfgStatus. However, as alsoexemplified in the Fig. 9, new UEs entering the cell 201 after the DCI has beenprovided (UE2) might miss out on the activation status. As such UE2 will need to assume that no additional ROs are allowed to be used unless the gNB (re- )transmits the DCI containing RoCfgStatus. Constant retransmission of the DCI is not a desired process for the gNB as such extra transmissions imply extra energy consumption. The disclosed technique utilize the fact that SIBx content (e.g., an RRCinformation), which is subject and / or bound to SI modification boundaries, iswithin the PDSCH part of the SIBx transmission, while the accompanied DCI scrambled with SI-RNTI used for providing the physical layer information is not.Fig. 10 schematically illustrates an example of the configuration message 802 andassociated scheduling DCI as the control message 804, which messages may be used in any embodiment of the devices 100 and 200 and the methods 300 and 400.A main principle of any embodiment may enable use of more efficient signalingschemes that separate the dynamic RO availability indication (i.e., the control message 804 or 806 for the activation status or "RoCfgStatus") from itsconfiguration information (i.e., the configuration message 802).This may be done by a combination of both a separate DCI 806 and the SIBx-accompanied DCI 804 to convey RoCfgStatus to the UEs 100 of the cell 201. Thisscheme is exemplified in the Fig. 8. As can be seen, UE2 100 entering the cell 201will also, as part of its SIBx 802 reading, become aware of the RoCfgStatus. TheTelefonaktiebolaget LM Ericsson (publ) 31 / 47P112168WO01 25 Sep 2025reason for the two DCIs 804 and 806 in this scheme is that existing UEs 100 in thecell 201 need not be forced to wake up an extra time per paging cycle (DRX cycle)to read the SIBx DCI 804, instead for these UEs 100 already in the cell the secondDCI 806 is provided at an occasion in which the UE 100 is already awake, e.g., in the Paging / PEI DCI occasion of the UE1. Such schemes may be generally described via the following steps:1. The UE 100 obtains legacy RO and additional RO configuration info 802 aspart of SIBx.2. The UE 100 obtains info 804 or 806 as to whether additional RO is currentlyavailable / activated (RoCfgStatus): Current status info, status change info, etc.3. If the availability info (RoCfgStatus) indicates that the additional RO iscurrently OFF (i.e. inactive or deactivated), the UE 100 performs RACHprocedure according to the legacy RO configuration. On the other hand, if RoCfgStatus indicates that the additional RO is currently ON (i.e., available,activated or active), the UE 100 performs RACH procedure according to theadditional RO configuration 802. In one embodiment, if RoCfgStatus indicatesthat the additional RO 702 is currently ON, the UE 100 may perform RACHbased on the union of (i.e., any of) the legacy and additional RO. In yet another embodiment, when additional ROs 702 are activated, the RoCfgStatus indicates further whether only the additional or the union of both additional and legacy may be used. In one aspect, the availability info (RoCfgStatus) may indicate that a subset of the configured additional ROs is turned ON. In one aspect, the gNB 200 can indicate different availability information (RoCfgStatus) to different UEs. For example, for one or more first UEs or group(s) of UEs, the additional ROs are OFF / not available, while for second UEs only a subset is ON / available, and for a third set of UEs all ROs are ON / available, etc. In one embodiment, the different availability information (RoCfgStatus) provision is done by means of DCI transmission at different occasions, such as in different paging occasions with different contents each addressing different UEs. In another embodiment, a DCI includes different RoCfgStatus fields for different UEgroups, i.e., each UE group only obey the RoCfgStatus relevant for the group. TheUEs in this embodiment are in addition to the additional RO configuration alsoTelefonaktiebolaget LM Ericsson (publ) 32 / 47P112168WO01 25 Sep 2025preconfigured with which bits within the DCI that is conveying the group-specific RoCfgStatus. In yet another embodiment, a bitmap (e.g., each bit representing a UE group) in the DCI informs for which group the additional ROs are (de- )activated / (not)available. Any embodiment may perform any one of the following example signaling timelines to support additional RO provision. Using the additional RO configuration signaling and additional RO availability signaling actions, a number of effective signaling solutions may be devised. Some examples are provided below. For the purposes of providing concrete examples, we use following timeline assumptions: -SIBx TTI (contents unchanged): 160 ms- SIBx transmission period: 80 ms- UE DRX period (i.e., paging cycle): 1.28 s- 1 PO per paging frame; every frame is a paging frame- Typical additional RO availability duration: at least 10 s0. Baseline solution using legacy signaling principles The additional RO configuration info is located in a new SIBx or as an additional information element (IE) in and existing SIBx when the additional ROs are available, and the configuration info is not present when they are not available. When the availability status changes, the configuration info is inserted or removed, as appropriate, and a SI update signaling is performed. In a related embodiment, the additional RO configuration is added to and removed from the legacy RO information IE in SIB1, where the change is similarly indicated via SI update signaling. Configuration signaling by NW: SIB1 payload contains legacy RO and additional RO configuration. Alternatively, the additional RO configuration info may be provided in a separate SIBx. Current status indication by NW: If the additional RO configuration is present in SIB1 / SIBx, the ROs are available. If the additional RO configuration is not present, the ROs are not available.Telefonaktiebolaget LM Ericsson (publ) 33 / 47P112168WO01 25 Sep 2025Status switch indication by NW: Status switch is indirectly indicated via SI update short message in the paging DCI. The UE then checks the SIB1 / SIBx contexts at the next occasion. (Not all SI update indications lead to additional RO status updates.). Validity assumptions: The validity assumption for an additional RO configuration present in SIB1 / SIBx can be same as the validity assumption for other IEs in the SIB1 / SIBx, i.e. the additional RO configuration is valid (i.e. additional ROs are available) until the UE receives a SIB1 / SIBx change notification or a SIB1 / SIBx timer (e.g.3 hours) elapses. UE actions: A UE reselecting to the cell reads the SIBx payload to obtain additional RACH configuration info and implied availability of the additional RO. Subsequently, the UE updates its status information by checking the SIBx contents when SI update indication is received via paging DCI. In aspects below with DCI-based availability indication, there could be embodiments in which one or both DCIs include indicators for whether the activated additional ROs are relevant for (allowed to be used by) RRC_IDLE, or RRC_INACTIVE, or RRC_CONNECTED UEs. For example, 2 bits could be used in the DCI where 00 means for RRC_IDLE / INACTIVE UEs and 01 means for RRC_CONNECTED UEs, and 11 means for both RRC_IDLE / INACTIVE and RRC_CONNECTED UEs. Note that this is an example, finer or coarser granularity can also be used by more or fewer bits to address UEs of said states. A. DCI-based availability indication in SIBx scheduling DCI Configuration signaling by NW: SIBx payload contains additional RO configuration, optionally including a validity time T (preferably set by the NW equal to the largest DRX cycle in the cell, or a multiple thereof). The additional RO configuration may include one or more legacy / baseline RO instances, or itmay be disjoint with respect to the legacy RO pattern; the latter option includesthe embodiment where the additional RO configuration is provided as a deltawith respect to the legacy / baseline RO pattern.Current status indication by NW: SIBx scheduling DCI uses one currently reserved bit (e.g. using the detailed signaling described in subclause 2.7.1.3) to show whether the additional ROs are currently ON / OFF (1 / 0). When the additional RO is activated, the NW sets the indication to ON the next SIBxTelefonaktiebolaget LM Ericsson (publ) 34 / 47P112168WO01 25 Sep 2025occasion. When the additional RO is inactivated, the NW sets the indication to OFF at the SIBx occasion T time units before the before the inactivation. Status switch indication by NW: There is no separate state switching signaling outside the SIBx transmission times; any state switch occurs at these points. Validity assumptions: The UE assumes the additional ROs are available for T time units after reading the availability indication =1 in the scheduling DCI. The cell keeps the additional ROs on for T time units after the latest SIBx transmission where the indication =1. UE actions: A UE reselecting to the cell reads the SIBx payload to obtain additional RACH configuration info and the status bit in the corresponding SIBx scheduling DCI to obtain the current availability status. Subsequently, the UE updates its status info by checking the SIBx scheduling DCI every Paging cycle, once every N paging cycles, or every T time units (preferably, if T=DRX period, close to its PO monitoring). B. DCI-based availability and status change indication Configuration signaling by NW: As in A. Current status indication by NW: As in A. Status switch indication by NW: When the additional RO status is changed (ONto OFF, OFF to ON), the paging DCI indicates via a new short message, or viaother reserved bits within the P-RNTI encoded DCI. In another embodiment, the PEI DCI (DCI 2_7) is used for the status switching. Validity assumptions: The UE 100 assumes that the current status of the additional RO 702 is valid until a new status switch indication is received. The cell 201 or the corresponding network node 200 keeps the additional ROs 702 on for T time units after the latest SIBx transmission where the indication equals 1.When receiving an OFF to ON switching indication, the UE assumes the additionalRO are immediately available (the current status indication in the scheduling DCI has had the status ON since at least the most recent SIBx occasion). Whenreceiving an ON to OFF switching indication, the UE assumes the additional ROare no longer available (the current status indication in the scheduling DCI has had the status OFF since at least the most recent SIBx occasion).Telefonaktiebolaget LM Ericsson (publ) 35 / 47P112168WO01 25 Sep 2025UE actions: A UE 100 reselecting to the cell reads the SIBx payload to obtainadditional RACH configuration info and the status bit in the corresponding SIBx scheduling DCI to obtain the current availability status. Subsequently, the UE monitors its PO and receives any status switch info via the short message in thepaging DCI 806. The UE 100 may additionally double-check / verify its statusassumption by checking the SIBx-scheduling DCI 804 occasionally, close to its PO monitoring.Fig. 11 further depicts the signaling sequence for example C:In one related embodiment, the status switch signaling via the paging DCI may be used to indicate the additional RO availability individually to different UEs or UEgroups. In this embodiment, to avoid misalignment between the paging DCI- andSIBx-DCI-based indications, one or more UEs that receive individual indications via the paging DCI may be configured or indicated whether to use the current status indication in the SIBx-DCI. Such configuration may be provided in an RRC_RELEASE message or via other RRC signaling, or such indication may be provided via DCI signaling. Alternatively, the status switch signaling in the paging DCI may include a flag whether the indication is cell-specific or UE / group specific; in the latter case, the UE may not use SIBx-DCI-based current status indication. The individual indication may be associated with a validity duration during which the SIBx-DCI indication is ignored; after the validity expires and the UE has notreceived a new individual indication, the SIBx-DCI- and paging DCI-basedindication may be assumed to be aligned again. C. Alternation of B. Configuration signaling by NW: As in B. Current status indication by NW: As in B. Status switch indication by NW: As in B. Validity assumptions: The UE assumes the additional ROs are available as soon as it reads the availability indication =1 in the SIBx scheduling DCI, and a validity timer starts. If the UE still stays in idle and receives an ON indication through paging / PEI DCI, the timer refreshes. The indication in SIBx turns to OFF after the timer runs out. The SIBx after the first SIBx which indicates the ON state of ROTelefonaktiebolaget LM Ericsson (publ) 36 / 47P112168WO01 25 Sep 2025compensate the validity timer based on the time offset between paging DCI and previous SIBx. UE actions: A UE reselecting to the cell reads the SIBx payload to obtain additional RACH configuration info and the status bit in the corresponding SIBx scheduling DCI to obtain the current availability status. It assumes the ROs are available immediately after the indication of SIBx until the timer runs out. Subsequently, the UE monitors its PO and refresh the timer once receives the indication in the paging / PEI DCI. A UE, which has already camped on the cell before the SIBx indication turns to ON, monitors its PO and if a ON indication via paging / PEI DCI is received, it starts the validity timer.The Fig. 12 provides an example on how the timer 1204 is refreshed:The Fig. 13 provides an example on how to use timer 1202 and 1204 to provideROs 702 for each group of UEs 100 in order. In one embodiment, each timer corresponds to its own activation indication. The time in first msg tells the valid duration since the activation indication in the first msg`s DCI. The second timer in the second msg tell the duration from the activation indication from the second DCI indication of the second msg. etc. Any embodiment may comprise at least one of the following additional details of DCI-based signaling. In the following some additional details of the DCI-based signaling are disclosed.A. Configuration details of the DCI fieldsIn an embodiment, UE obtains a higher layer parameter that indicates thepresence of a field (Field1) for indication of availability and / or activation and / orunavailable and / or deactivation of additional RO (or RACH resources) associatedwith an additional RACH configuration in at least one or more of a DCI format 1_0 with CRC scrambled by SI-RNTI, DCI format 1_0 with CRC scrambled by P-RNTI, and a DCI format 2_7 with CRC scrambled by PEI-RNTI. In an embodiment, the UE further obtains a higher layer parameter indicating at least length of the field (Field1) within the DCI format 1_0 with CRC scrambled by SI-RNTI. In an example, the field is located immediately after a System information indicator field in the DCI format. In an example, the location of theTelefonaktiebolaget LM Ericsson (publ) 37 / 47P112168WO01 25 Sep 2025field within the DCI format is configured by higher layers, and the field can be located within a range of fifteen bits after the System information indicator field in the DCI. In yet another example, the location of the field within the DCI format is configured by higher layers, and the field can be located at any location within the DCI (e.g. anywhere from position 0 to 42 bits). In an embodiment, the UE further obtains a higher layer parameter indicating at least length of the field (Field2) within the DCI format 1_0 with CRC scrambled by P-RNTI. In an example, the field is located immediately after a TRS availability indication (if configured) or after a TB Scaling field in the DCI format. In an example, the location of the field within the DCI format is configured by higher layers, and the field can be located within a range of N bits after the TRS availability indication (if configured) or a TB scaling field in the DCI format, when N >0. In yet another example, the location of the field within the DCI format is configured by higher layers, and the field can located at any location within the DCI (e.g. anywhere from position 0,….42 bits). In an embodiment, the UE further obtains a higher layer parameter indicating at least position of the field (Field1) within the DCI format 2_7 with CRC scrambled by PEI-RNTI, wherein the position is 0 and 43 bits. In an example, the location of the field within the DCI format is configured by higher layers, and the field can be located within a range of N bits after the TRS availability indication (if configured) or a Paging indicator field in the DCI format, when N >0. In yet another example, the location of the field within the DCI format is configured by higher layers, and the field can located at any location within the DCI (e.g. anywhere from position0 to 42 bits).B. DCI field linkage in case of adaptation of multiple additional RACH resourcesIn an embodiment, the UE may be configured with multiple sets of additional RACH resources (e.g. that may be adapted). For a set of additional RACH resources, higher layers can configure a set index and / or a bit index. The set index (or bit index) is used to determine the field and / or bit location within the DCI for indication of availability / activation / unavailable / deactivation of the additional ROs (or RACH resources) of the set within a DCI format. For instance, a first set of additional RACH resources may have a set index (or bit index) 0, and a second set of additional RACH resources may have a set index (or bit index) 1. In this case, the field may have a block of two bits, or two blocks each comprisingTelefonaktiebolaget LM Ericsson (publ) 38 / 47P112168WO01 25 Sep 2025one bit, and wherein each bit is associated with a respective set of additional resources. For example, a first set of additional RACH resources may be configured for 4- step RACH procedure. A second set of additional RACH resources may be configured for a 2-step RACH procedure. In yet another example, a set of additional RACH resources may be configured for a first type of slice e.g. in cases where slice-based RACH is configured in the cell. For instance, a set of additional RACH resources may be configured for NR Coverage Enhancements, another set of additional RACH resources may be configured for Reduced Capability devices (see Section 4.7); and another set of additional RACH resources may be configured for Small Data Transmission. Each such set of additional RACH resources may have an associated set index (or bit index) , and the set index (or bit index) may be used to determine the field and / or bit location within the DCI for indication of availability / activation / unavailability / deactivation of the additional ROs (or RACH resources) of the set within a DCI format. In some embodiments, the configuration of additional RACH resources may also include at least of a DCI format, the location of the field with a DCI format availability / activation / unavailability / deactivation of the additional ROs (or RACH resources) of the set.An example is illustrated in Fig. 14, where the higher layers may indicate threeset of additional RACH resources. Each set may include at least the RACH resource information, and one or more of a set index (or bit index) and locationWithinDCI (or a position within DCI) to indicate the associated field for indication of availability / activation / unavailability / deactivation of the additional ROs (or RACH resources) of the set within a DCI format. In another embodiment, the DCI may be configured with a positionWithinDCI parameter to identify thelocation of a field block for indication of availability and / or activation and / orunavailability and / or deactivation of the additional ROs 702, and the set index (orbit index) is used to identify the position within the field block of the field associated with the indication of a particular set of additional RACH resources.In some examples, the set index and bit index may be same. In some examples,the set index and bit index may be different. In some examples, only a set indexmay be configured. In some examples, only a bit index may be configured.Fig. 14 schematically illustrates a DCI format containing field for indication of oneor multiple set of additional RACH resources.Telefonaktiebolaget LM Ericsson (publ) 39 / 47P112168WO01 25 Sep 2025Fig. 15 schematically illustrates a DCI format containing field for indication of oneor multiple set of additional RACH resources. In certain embodiments, the field in the DCI may also be used to indicate a ‘continue’ or reserved field that indicates that the UE may continue its previous assumption regarding availability or unavailability. This may be useful in instances wherein the gNB wishes to continue sending the DCI format for regular scheduling of paging messages but does not wish to extend the validity indication.C. DCI content in case of RACH partition adaptation of multiple additionalRACH resources In one embodiment, a RACH configuration Index is shared between of multiple additional RACH resources. Then after the field and / or bit location of each additional RACH resource, there may also be a RACH mask and / or preamble index following, to specify the ROs and / or preambles for current RACH resource.For example, if a UE is indicated by a PDCCH order for RACH and the RACHconfiguration is given, the UE applies a RACH mask and / or RACH preambles among multiple RACH masks and / or preambles for RACH corresponding to the RACH resource that is given.Fig. 16 shows a schematic block diagram for an embodiment of the device 100. Thedevice 100 comprises processing circuitry, e.g., one or more processors 1604 forperforming the method 300 and memory 1606 coupled to the processors 1604.For example, the memory 1606 may be encoded with instructions that implementat least one of the modules 102, 104 and 106.The one or more processors 1604 may be a combination of one or more of amicroprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and / or encoded logic operable to provide, either alone or in conjunction with other components of the device 100, such as the memory 1606,radio device functionality. For example, the one or more processors 1604 mayexecute instructions stored in the memory 1606. Such functionality may include providing various features and steps discussed herein, including any of the benefitsTelefonaktiebolaget LM Ericsson (publ) 40 / 47P112168WO01 25 Sep 2025disclosed herein. The expression "the device being operative to perform an action" may denote the device 100 being configured to perform the action. As schematically illustrated in Fig.16, the device 100 may be embodied by a radiodevice 1600, e.g., functioning as a UE attempting radio access. The radio device1600 comprises a radio interface 1602 coupled to the device 100 for radiocommunication with one or more network node, e.g., functioning as base stations of the RAN.Fig. 17 shows a schematic block diagram for an embodiment of the device 200. Thedevice 200 comprises processing circuitry, e.g., one or more processors 1704 forperforming the method 400 and memory 1706 coupled to the processors 1704.For example, the memory 1706 may be encoded with instructions that implementat least one of the modules 202, 204 and 206.The one or more processors 1704 may be a combination of one or more of amicroprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, microcode and / or encoded logic operable to provide, either alone or in conjunction with other components of the device 200, such as the memory 1706,network node functionality. For example, the one or more processors 1704 mayexecute instructions stored in the memory 1706. Such functionality may include providing various features and steps discussed herein, including any of the benefitsdisclosed herein. The expression "the device being operative to perform an action"may denote the device 200 being configured to perform the action. As schematically illustrated in Fig.17, the device 200 may be embodied by a network node 1700, e.g., functioning as a base station of the RAN. The networknode 1700 comprises a radio interface 1702 coupled to the device 200 for radiocommunication with one or more radio devices, e.g., functioning as UEs. With reference to Fig.18, in accordance with an embodiment, a communication system 1800 includes a telecommunication network 1810, such as a 3GPP-type cellular network, which comprises an access network 1811, such as a radio access network, and a core network 1814. The access network 1811 comprises a plurality of base stations 1812a, 1812b, 1812c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1813a, 1813b,Telefonaktiebolaget LM Ericsson (publ) 41 / 47P112168WO01 25 Sep 20251813c. Each base station 1812a, 1812b, 1812c is connectable to the core network 1814 over a wired or wireless connection 1815. A first user equipment (UE) 1891 located in coverage area 1813c is configured to wirelessly connect to, or be paged by, the corresponding base station 1812c. A second UE 1892 in coverage area 1813a is wirelessly connectable to the corresponding base station 1812a. While a plurality of UEs 1891, 1892 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1812. Any of the base stations 1812 may be embodied by the network node 200, and the UEs 1891, 1892 may embody the radio device 100. The telecommunication network 1810 is itself connected to a host computer 1830, which may be embodied in the hardware and / or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 1830 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 1821, 1822 between the telecommunication network 1810 and the host computer 1830 may extend directly from the core network 1814 to the host computer 1830 or may go via an optional intermediate network 1820. The intermediate network 1820 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 1820, if any, may be a backbone network or the Internet; in particular, the intermediate network 1820 may comprise two or more sub-networks (not shown). The communication system 1800 of Fig.18 as a whole enables connectivity between one of the connected UEs 1891, 1892 and the host computer 1830. The connectivity may be described as an over-the-top (OTT) connection 1850. The host computer 1830 and the connected UEs 1891, 1892 are configured to communicate data and / or signaling via the OTT connection 1850, using the access network 1811, the core network 1814, any intermediate network 1820 and possible further infrastructure (not shown) as intermediaries. The OTT connection 1850 may be transparent in the sense that the participating communication devices through which the OTT connection 1850 passes are unaware of routing of uplink and downlink communications. For example, a base station 1812 need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 1830 to be forwarded (e.g., handed over) to aTelefonaktiebolaget LM Ericsson (publ) 42 / 47P112168WO01 25 Sep 2025connected UE 1891. Similarly, the base station 1812 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1891 towards the host computer 1830. By virtue of the method 300 being performed by any one of the UEs 1891 or 1892and / or any one of the base stations 1812 performing the method 400, theperformance or range of the OTT connection 1850 can be improved or established,e.g., in terms of increased throughput and / or reduced latency. More specifically, the host computer 1830 may indicate to the RAN 500 (e.g., the network node 200) or the radio device 100 (e.g., on an application layer) the availability of user data for triggering the random access. As has become apparent from above description, at least some embodiments of the technique allow efficient signaling (e.g., regarding RAN resources and / orenergy consumption) and / or monitoring (e.g., regarding UE energy consumption)of an availability of additional ROs (i.e., conditional ROs). This allows dynamic adaptation of the additional ROs by the RAN (e.g., the network node), optionally maximizing NES without degrading RAN access latency and / or without compromising user experience when the RACH load is high. At least someembodiments simultaneously allow all UEs 100, regardless of when they havereselected to a cell, to (e.g., maximally) utilize all available ROs.Many advantages of the present invention will be fully understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the units and devices without departing from the scope of the invention and / or without sacrificing all of its advantages. Since the invention can be varied in many ways, it will be recognized that the invention should be limited only by the scope of the following claims.

Claims

1. Telefonaktiebolaget LM Ericsson (publ) 43 / 47P112168WO01 25 Sep 2025Claims1. A method (300) performed by a radio device (100; 1600) for transmitting arandom access, RA, preamble in a radio access network, RAN (500), the method (300) comprising: receiving (302), from the RAN (500), a configuration message (802) indicative of conditional RA occasions, ROs (702), that are subject to an activation status; and transmitting (306), to the RAN (500), the RA preamble in at least one of the conditional ROs (702) if the activation status is active.

2. The method (300) of claim 1, wherein the configuration message (802) is orcomprises a system information block type 1, SIB1.

3. The method (300) of claim 1 or 2, further comprising receiving (304), fromthe RAN (500), a control message (804; 806) indicative of the activation status of the conditional ROs (702).

4. The method (300) of any one of claims 1 to 3, wherein at least one of theconfiguration message (802) and the control message (804; 806) is indicative of a validity duration (1204) for a validity timer.

5. The method (300) of claim 3 or 4, wherein the control message (804; 806) isdownlink control information, DCI.

6. The method (300) of any one of claims 3 to 5, wherein the control message(804; 806) comprise an indicator that is indicative of an activation status of the conditional ROs (702).

7. The method (300) of any one of claims 3 to 6, wherein a format of thecontrol message (804; 806) is DCI format 1_0.

8. The method (300) of any one of claims 3 to 7, wherein the control message(804; 806) is further indicative of scheduling information for a paging message in the RAN (500) and / or wherein the control message (804; 806) is a paging DCI.Telefonaktiebolaget LM Ericsson (publ) 44 / 47P112168WO01 25 Sep 20259. The method (300) of any one of claims 3 to 8, wherein a cyclic redundancycheck, CRC, of the control message (804; 806) is scrambled with a radio network temporary identifier, RNTI, for paging, P-RNTI.

10. The method (300) of any one of claims 3 to 9, wherein the control message(804; 806) is a DCI for a paging message.

11. The method (300) of any one of claims 1 to 10, wherein the configurationmessage (802) is indicative of a plurality of conditional ROs (702), optionally periodic ROs (702); and / or wherein the transmitting (306) of the RA preamble comprises selecting one or at least one of the conditional ROs (702) for which the activation status is active.

12. A method (400) performed by a network node (200; 1700) for receiving arandom access, RA, preamble in a radio access network, RAN (500), the method (400) comprising: broadcasting (402) or groupcasting (402), to radio devices (100; 1600), a configuration message (802) indicative of conditional RA occasions, ROs (702), that are subject to an activation status; and receiving (406), from at least one of the radio devices (100; 1600), the RA preamble in at least one of the conditional ROs (702) if the activation status is active.

13. The method (400) of claim 12, wherein the configuration message (802)comprises a system information block, SIB, optionally a SIB type 1, and / or an energy saving SIB and / or an SIB dedicated for configuring the conditional ROs (702).

14. The method (400) of claim 12 or 13, further comprising broadcasting (404),to the radio devices (100; 1600), or groupcasting (404), to a subset of the radio devices (100; 1600), a control message (804; 806) indicative of the activation status of the conditional ROs (702).

15. The method (400) of any one of claims 12 to 14, further comprising thesteps or features of any one of claims 2 to 11 or any step or feature corresponding thereto.Telefonaktiebolaget LM Ericsson (publ) 45 / 47P112168WO01 25 Sep 202516. The method (400) of any one of claims 12 to 15, wherein the controlmessage (804; 806) comprises multiple DCIs for a paging message or a paging early indication in multiple paging occasions, POs, optionally wherein the activation status indicated by the DCIs in different POs is different.

17. A computer program product comprising program code portions forperforming the steps of any one of the claims 1 to 11 and / or 12 to 16 when the computer program product is executed on one or more computing devices (1604; 1704), optionally stored on a computer-readable recording medium (1606; 1706).

18. A radio device (100; 1600) for transmitting a random access, RA, preamblein a radio access network, RAN (500), the radio device (100; 1600) comprisingmemory operable to store instructions and processing circuitry operable to execute the instructions, such that the radio device (100; 1600) is operable to: receive (302), from the RAN (500), a configuration message (802) indicative of conditional RA occasions, ROs (702), that are subject to an activation status; and transmit (306), to the RAN (500), the RA preamble in at least one of the conditional ROs (702) if the activation status is active.

19. The radio device (100; 1600) of claim 18, further comprising the featuresand operable to perform the steps of any one of claims 2 to 11.

20. A radio device (100; 1600) for transmitting a random access, RA, preamblein a radio access network, RAN (500), the radio device (100; 1600) beingconfigured to: receive (302), from the RAN (500), a configuration message (802) indicative of conditional RA occasions, ROs (702), that are subject to an activation status; and transmit (306), to the RAN (500), the RA preamble in at least one of the conditional ROs (702) if the activation status is active.

21. The radio device (100; 1600) of claim 20, further comprising the featuresand configured to perform the steps of any one of claims 2 to 11.

22. A network node (200; 1700) for receiving a random access, RA, preamble ina radio access network, RAN (500), the network node (200; 1700) comprising memory operable to store instructions and processing circuitry operable to execute the instructions, such that the network node (200; 1700) is operable to:Telefonaktiebolaget LM Ericsson (publ) 46 / 47P112168WO01 25 Sep 2025broadcast (402) or groupcast (402), to radio devices (100; 1600), a configuration message (802) indicative of conditional RA occasions, ROs (702), that are subject to an activation status; and receive (406), from at least one of the radio devices (100; 1600), the RA preamble in at least one of the conditional ROs (702) if the activation status is active.

23. The network node (200; 1700) of claim 22, further comprising the featuresand operable to perform the steps of any one of claims 13 to 16.

24. A network node (200; 1700) for receiving a random access, RA, preamble ina radio access network, RAN (500), the network node (200; 1700) being configured to: broadcast (402) or groupcast (402), to radio devices (100; 1600), a configuration message (802) indicative of conditional RA occasions, ROs (702), that are subject to an activation status; and receive (406), from at least one of the radio devices (100; 1600), the RA preamble in at least one of the conditional ROs (702) if the activation status is active.

25. The network node (200; 1700) of claim 24, further comprising the featuresand configured to perform the steps of any one of claim 13 to 16.

26. A communication system (1800) including a host computer (1830)comprising: processing circuitry configured to provide user data; and a communication interface (1816) configured to forward the user data to a cellular or ad hoc radio network (500; 1810) for transmission to a radio device (100; 1600) wherein the radio device (100; 1600) comprises a radio interface (1602) and processing circuitry (1604), the processing circuitry (1604) of the radio device (100; 1600) being configured to execute the steps of any one of claims 1 to 11 responsive to a paging message indicating the availability of the user data.

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