Dynamic handling of on-demand SIB1 transmission modes

Abstract

Methods, apparatuses, and systems are provided for a user equipment, (UE), in radio resource control, (RRC), idle or inactive mode for acquiring system information block 1, (SIB1), information of a cell operating in an on-demand SIB1 mode. The UE receives configuration information related to acquisition of SIB1 information of the cell, wherein the configuration information comprises information for transmitting an on-demand SIB1 request, for receiving an on-demand SIB1 response, and for receiving on-demand SIB1 information. In response to transmitting the on-demand SIB1 request for acquiring SIB1 information of the cell, the UE receives the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to transmission parameters for SIB1. Finally, the UE receives the SIB1 information according to the configuration information and the assistance information. Similar methods, apparatuses, and systems are provided for a network entity, too.

Description

DYNAMIC HANDLING OF ON-DEMAND SIB1 TRANSMISSION MODESTHECHNIC AL FIELD

[0001] The subject disclosure generally relates to wireless communication systems and, in particular, to on-demand system information block 1 (SIB1) procedures or to enablers thereof. Yet more particularly, the subject disclosure provides methods and apparatuses for dynamic handling of on-demand SIB1 transmission modes.BACKGROUND

[0002] Wireless telecommunication systems, also referred to mobile communication systems, are under constant development. One crucial aspect in these mobile communication systems is energy saving. For user equipments (UEs), several techniques have been developed, such as discontinuous reception (DRX), energy saving in Radio Resource Control (RRC) inactive and idle modes, etc., but many techniques for network energy savings (NES) are still in early phases of their development.

[0003] Usually, for example in the 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) mobile communication system, system information (SI) is broadcasted periodically over the entire cell area to inform UEs about parameters of the network in a continuous manner. The main drawback of this continuous broadcasting is a low energy efficiency, in particular, if a cell is faced with a low load or with no load in the cell (i.e., there are few or no UEs to benefit from the transmitted SI).

[0004] In the 3GPP 5th generation (5G) / New Radio (NR) mobile communication system, transmission of system information of other SI than minimum SI may be omitted. Minimum SI relates to information relating to master information block (MIB) and system information block 1 (SIB 1). The information of SIB2 to SIB19 may, additionally or alternatively to broadcasting, provided on demand. MIB and SIB1 are currently still broadcasted regularly in NR to carry basic information required for initial access of the UEs.

[0005] A further enhancement of NES could be to also provide SIB1 information only on demand. However, since SIB1 comprises essential system information for communicating with a cell, the procedures for on-demand SIB2 to SIB 19 may not be applied. Hence, methods and apparatuses supporting acquisition of SIB1 information of a cell operating in an on-demand SIB 1 mode are required.SUMMARY

[0006] According to a first aspect of the subject disclosure, a method performed by a user equipment, UE, in radio resource control, RRC, idle or inactive mode for acquiring system information block 1, SIB1, information of a cell operating in an on-demand SIB1 mode is provided. The method comprises receiving configuration information related to acquisition of SIB1 information of the cell, wherein the configuration information comprises information for transmitting an on-demand SIB 1 request, for receiving an on-demand SIB 1 response and for receiving on-demand SIB1 information, in response to transmitting the on-demand SIB1 request for acquiring SIB1 information of the cell, receiving the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE, and receiving the SIB1 information according to the configuration information and the assistance information.

[0007] According to a second aspect, a method performed by a network entity for providing system information block 1, SIB1, information of a cell to a user equipment, UE, in radio resource control, RRC, idle or inactive mode, wherein the cell operates in an on-demand SIB 1 mode, is provided. The method comprises transmitting configuration information related to acquisition of SIB1 information of the cell, wherein the configuration information comprises information for transmitting an on-demand SIB1 request, for receiving an on-demand SIB1 response and for receiving on-demand SIB1 information, in response to receiving the on- demand SIB1 request for acquiring SIB1 information of the cell, transmitting the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE and transmitting the SIB1 information according to the configuration information and the assistance information.

[0008] According to a third aspect, an apparatus of a user equipment, UE, operating in radio resource control, RRC, idle or inactive mode is provided, which is configured to receive configuration information related to acquisition system information block 1, SIB1, information of a cell operating in an on-demand SIB1 mode, wherein the configuration information comprises information for transmitting an on-demand SIB1 request, for receiving an on- demand SIB1 response and for receiving on-demand SIB1 information, in response to transmitting the on-demand SIB1 request for acquiring SIB1 information of the cell, receive the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmissionparameters to be used for SIB1 acquisition by the UE, and receive the SIB1 information according to the configuration information and the assistance information.

[0009] According to a fourth aspect, an apparatus of a network entity is provided, which is configured to transmit configuration information related to acquisition of system information block 1, SIB1, information of a cell operating in an on-demand SIB1 mode to a user equipment, UE, in radio resource control, RRC, idle or inactive mode, wherein the configuration information comprises information for transmitting an on-demand SIB1 request, for receiving an on-demand SIB1 response and for receiving on-demand SIB1 information, in response to receiving the on-demand SIB 1 request for acquiring SIB 1 information of the cell, transmit the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE, and transmit the SIB1 information according to the configuration information and the assistance information.

[0010] In embodiments, the one or more transmission parameters comprise one or more of a time-period, a periodicity, a number of repetitions, a specified transmission pattern, and a time offset before start of SIB1 transmission. In further embodiments, the SIB1 transmission mode is at least one of a regular periodic SIB1 transmission, a SIB1 transmission in a defined timeperiod, a number of SIB1 transmissions with a specified transmission pattern, and a SIB1 transmission start postponed by a time offset.

[0011] In embodiments, the SIB1 transmission mode and / or the one or more transmission parameters were selected by the cell based on at least one of a current traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE. In additional embodiments, the current radio conditions of the UE are indicated by the on-demand SIB1 request.

[0012] In embodiments, the on-demand SIB1 request is a first message, MSG1 or MSGA, or a third message, MSG3, in a random access procedure. In further embodiments, the on- demand SIB1 response is a second message, MSG2 or MSGB, or a fourth message, MSG4, in a random access procedure.

[0013] In embodiments, the configuration information includes values of the one or more transmission parameters to be used for SIB1 acquisition by the UE, and wherein the assistance information includes a modification of at least one transmission parameter of the one or more transmission parameters. In further embodiments, the modification of at least one transmission parameter includes at least one of overwriting one or more transmission parameters of the one or more transmission parameters to be used for SIB1 acquisition received within theconfiguration information and adding at least one transmission parameter to the one or more transmission parameters to be used for SIB1 acquisition received within the configuration information.

[0014] The above-noted aspects and features may be implemented in systems, apparatuses, methods, articles and non-transitory computer-readable media depending on the desired configuration. The subject disclosure may be implemented in and used with a number of different types of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices.

[0015] This summary is intended to provide a brief overview of some of the aspects and features according to the subject disclosure. Accordingly, it will be appreciated that the abovedescribed features are merely examples and should not be construed to narrow the scope of the subject disclosure in any way. Other features, aspects, and advantages of the subject disclosure will become apparent from the following detailed description, drawings and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A better understanding of the subject disclosure may be obtained when the following detailed description of various embodiments is considered in conjunction with the following drawings, in which:

[0017] FIG. 1 shows a schematic diagram of an example wireless network.

[0018] FIG. 2A shows a schematic diagram of an example wireless device.

[0019] FIG. 2B shows a schematic diagram of an example network node.

[0020] FIG. 3 is an overview on four possible scenarios for applying the methods described in this disclosure.

[0021] FIGs. 4 to 6 illustrate different possible information transfer scenarios according to the disclosure.

[0022] FIG. 7 presents a flow chart of a method performed by a user equipment according to the disclosure.

[0023] FIG. 8 presents a flow chart of a method performed by the network according to the disclosure.

[0024] FIG. 9 shows a message flow diagram of handling dynamic on-demand SIB1 transmission modes according to the disclosure.

[0025] FIG. 10 shows examples of SIB1 reception according to the indicated transmission mode according to the disclosure.DETAILED DESCRIPTION

[0026] The examples and embodiments set forth below represent information to enable those skilled in the art to practice the subject disclosure. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the description and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the description.

[0027] In the following description, numerous specific details are set forth. However, it is understood that embodiments may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure the understanding of the description. Those of ordinary skill in the art, with the included description, will be able to implement appropriate functionality without undue experimentation.

[0028] References in the specification to "one embodiment," "an embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0029] As used herein, "plurality" means two or more. As used herein, a "set" of items may include one or more of such items. As used herein, whether in the subject disclosure or the claims, the terms "comprising", "including", "carrying", "having", "containing", "involving", and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of' and "consisting essentially of', respectively, are closed or semi-closed transitional phrases with respect to claims. Use of ordinal terms such as "first", "second", "third", etc., in the claims or the subject disclosure to modify an element does not by itself connote any priority, precedence, or order of one element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one element having a certain name from another element having a same name (butfor use of the ordinal term) to distinguish the elements. As used herein, "and / or" and "at least one of means that the listed items are alternatives, but the alternatives also include any combination of the listed items.

[0030] Before explaining the examples according to the subject disclosure in detail, certain general principles of a wireless communication system are briefly explained with reference to FIGS. 1 to 3 to assist in understanding the technology underlying the described examples.

[0031] FIG. 1 illustrates an example of a wireless network 100 that may be used for wireless communications. Wireless network 100 includes wireless devices, such as UEs 110 (e.g., 110A-110B), and network nodes, such as radio access nodes 120 (e.g., 120A-120B) (e.g., eNBs, gNBs, etc.), connected to one or more network nodes 130 over an interconnecting network 125. The network 100 may use any suitable deployment scenarios. UEs 110 within coverage area 115 may each be capable of communicating directly with radio access nodes 120 over a wireless or air interface. In some embodiments, UEs 110 may also be capable of communicating with each other via D2D communication.

[0032] As an example, UE 110A may communicate with radio access node 120A over a wireless or air interface. That is, UE 110A may transmit wireless signals to and / or receive wireless signals from radio access node 120A. The wireless signals may contain voice traffic, data traffic, control signals, and / or any other suitable information.

[0033] As used herein, the term "user equipment" (UE) has the full breadth of its ordinary meaning and may refer to any type of wireless device which may communicate with a network node and / or with another UE in a cellular or mobile or wireless communication system. Examples of UE are target device, D2D UE, machine type UE or UE capable of machine-to- machine (M2M) communication, personal digital assistant, tablet, mobile terminal, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, ProSe UE, vehicle-to-vehicle (V2V) UE, V2X UE, MTC UE, eMTC UE, FeMTC UE, UE Cat 0, UE Cat Ml, narrow band loT (NB-IoT) UE, UE Cat NB1, etc. Example embodiments of a UE are described in more detail below with respect to FIG. 2A.

[0034] In some embodiments, an area of wireless signal coverage 115 associated with a radio access node 120 may be referred to as a cell. However, particularly with respect to the 5thgeneration (5G) / New Radio (NR) mobile communication concepts, beams, such as the herein described multicast radio beams (MRBs) may be used within cells for communication. In some embodiments described herein, the UE 110 may be in an RRC inactive or idle mode and camp on a cell of radio access node 120 A, which be denoted as anchor or coverage cell, and may be in the coverage area 115 of radio access nodes 120A and 120B. The cell of radio access node120B may be denoted as non-anchor or capacity cell. Although not shown in FIG. 1, there may be more than one non-anchor cell provided by more than one other radio access node 120. The UE 100 may, in some embodiments, may want to switch the cells, i.e., transition to camp on an non-anchor cell.

[0035] With respect to a beam-based mobile communication system, the radio access node 120 (base station) may transmit a beamformed signal to the UE 110 in one or more transmit directions (transmission beam, Tx beam). The UE 110 may receive the beamformed signal from the base station 120 in one or more receive directions (reception beam, Rx beam). The UE 110 may also transmit a beamformed signal to the base station 120 in one or more directions and the base station 120 may receive the beamformed signal from the UE 110 in one or more directions. The base station 120 and the UE 110 may determine the best receive and transmit directions, e.g., best in the sense of these directions leading to the highest link quality or fulfilling other quality conditions in the most suitable manner, for each of the base station / UE pairs.

[0036] The interconnecting network 125 may refer to any interconnecting system capable of transmitting audio, video, signals, data, messages, etc., or any combination of the preceding. The interconnecting network 125 may include all or a portion of a public switched telephone network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, or any other suitable communication link, including combinations thereof.

[0037] In some embodiments, the network node 130 may be a core network node, managing the establishment of communication sessions and other various other functionalities for UEs 110. Examples of network node 130 may include mobile switching center (MSC), MME, serving gateway (SGW), packet data network gateway (PGW), operation and maintenance (O&M), operations support system (OSS), SON, positioning node (e.g., Enhanced Serving Mobile Location Center, E-SMLC), location server node, MDT node, etc. UEs 110 may exchange certain signals with the network node 130 using the non-access stratum (NAS) layer. In non-access stratum signaling, signals between UEs 110 and the network node 130 may be transparently passed through the radio access network. In some embodiments, radio access nodes 120 may interface with one or more network nodes 130 over an internode interface.

[0038] As used herein, the term "network node" has the full breadth of its ordinary meaning and may correspond to any type of radio access node (or radio network node) or any network node, which may communicate with a UE and / or with another network node in a cellular ormobile or wireless communication system. Examples of network nodes are NodeB, MeNB, SeNB, a network node may belonging to MCG or SCG, base station (BS), multi-standard radio (MSR) radio access node such as MSR BS, eNodeB, network controller, radio network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), access point (AP), transmission point, transmission node, RRU, RRH, node in distributed antenna system (DAS), core network node (e.g., MSC, MME, etc.), O&M, OSS, Self-organizing Network (SON), positioning node (e.g., E-SMLC), MDT, test equipment, etc. Example embodiments of a network node are described in more detail below with respect to FIG. 8.

[0039] In some embodiments, radio access node 120 may be a distributed radio access node. The components of the radio access node 120, and their associated functions, may be separated into two main units (or sub-radio network nodes) which may be referred to as the central unit (CU) and the distributed unit (DU). Different distributed radio network node architectures are possible. For instance, in some architectures, a DU may be connected to a CU via dedicated wired or wireless link (e.g., an optical fiber cable) while in other architectures, a DU may be connected a CU via a transport network. Also, how the various functions of the radio access node 120 are separated between the CU(s) and DU(s) may vary depending on the chosen architecture.

[0040] In some embodiments, radio access nodes 120 may communicate with each other over terrestrial or other connections. The communication between the radio access nodes 120 may, e.g., in a 5G / NR communication system may be achieved by using an Xn interface connecting the radio access nodes 120.

[0041] Exemplary wireless communication systems are architectures standardized by the 3rd Generation Partnership Project (3GPP). A latest 3GPP based development is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology (RAT). The various development stages of the 3GPP specifications are referred to as releases. More recent developments of the LTE are often referred to as LTE Advanced (LTE-A). The LTE (LTE-A) employs a radio mobile architecture known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and a core network known as the Evolved Packet Core (EPC). Base stations of such systems are known as evolved or enhanced Node Bs (eNBs) and provide E-UTRAN features such as user plane Packet Data Convergence / Radio Link Control / Medium Access Control / Physical layer protocol (PDCP / RLC / MAC / PHY) and control plane Radio Resource Control (RRC) protocol terminations towards the communication devices. Other RAT examples comprise thoseprovided by base stations of systems that are based on technologies such as WLAN and / or Worldwide Interoperability for Microwave Access (WiMax). A base station may provide coverage for an entire cell or similar radio service area. Core network elements include Mobility Management Entity (MME), Serving Gateway (S-GW) and Packet Gateway (P-GW).

[0042] An example of a suitable communications system is the 5G or NR concept. Network architecture in NR may be similar to that of LTE-A. Base stations of NR systems may be known as next generation Node Bs (gNBs). Changes to the network architecture may depend on the need to support various radio technologies and finer Quality of Service (QoS) support, and some on-demand requirements for QoS levels to support Quality of Experience (QoE) of user point of view. Also network aware services and applications, and service and application aware networks may bring changes to the architecture. Those are related to Information Centric Network (ICN) and User-Centric Content Delivery Network (UC-CDN) approaches. NR may use multiple input-multiple output (MIMO) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates.

[0043] Future networks may utilize network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications this may mean node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head. It is also possible that node operations will be distributed among a plurality of servers, nodes, or hosts. It should also be understood that the distribution of labour between core network operations and base station operations may differ from that of the LTE or even be non-existent.

[0044] An example 5G core network (CN) comprises functional entities. The CN is connected to a UE via the radio access network (RAN). An UPF (User Plane Function) whose role is called PSA (PDU Session Anchor) may be responsible for forwarding frames back and forth between the DN (data network) and the tunnels established over the 5G towards the UEs exchanging traffic with the data network (DN). The UPF is controlled by an SMF (Session Management Function) that receives policies from a PCF (Policy Control Function). The CN may also include an AMF (Access & Mobility Function).

[0045] Generally, all concepts disclosed herein may be applicable to different communication networks, comprising but not limited to LTE, LTE-A, 5G, 5G advanced, 6G, and other future or already implemented networks.

[0046] FIG. 2A is a schematic diagram of an apparatus for the UE. In an embodiment, the apparatus may comprise the UE, in yet another embodiment the apparatus is comprised in the UE, and in another embodiment the apparatus is the UE. The apparatus may comprise a wireless device. The apparatus may comprise at least one processor 220 and at least memory 230 storing computer program instructions that, when executed by the at least one processor 220, cause the apparatus to carry out the embodiments of the UE 110 described herein. UE 110 includes a transceiver 210, processor 220, memory 230, and a network interface 240. In some embodiments, the transceiver 210 facilitates transmitting wireless signals to and receiving wireless signals from radio access node 120 (e.g., via transmitter(s) (Tx), receiver(s) (Rx) and antenna(s)). The processor 220 executes instructions to provide some or all of the functionalities described herein as being provided by UE 110, and the memory 230 stores the instructions executed by the processor 220. In some embodiments, the processor 220 and the memory 230 form processing circuitry.

[0047] The processor 220 may include any suitable combination of hardware to execute instructions and manipulate data to perform some or all of the described functions of UE 110 described herein. In some embodiments, the processor 220 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs) and / or other logic.

[0048] The memory 230 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and / or other instructions capable of being executed by a processor 220. Examples of memory 230 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or or any other volatile or non-volatile, non- transitory computer-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processor 220 of UE 110. For example, the memory 230 includes computer program code causing the processor 220 to perform processing according to the methods described herein, e.g., the method of FIG. 7.

[0049] The network interface 240 is communicatively coupled to the processor 220 and may refer to any suitable device operable to receive input for UE 110, send output from UE 110, perform suitable processing of the input or output or both, communicate to other devices, or any combination thereof. The network interface 240 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

[0050] Other embodiments of UE 110 may include additional components beyond those shown in FIG. 2 A that may be responsible for providing certain aspects of the wireless device’s functionalities, including any of the functionalities described herein and / or any additional functionalities (including any functionality necessary to support the mechanisms according to the subject disclosure). As an example, UE 110 may include input devices and circuits, output devices, and one or more synchronization units or circuits, which may be part of the processor 220. Input devices include mechanisms for entry of data into UE 110. For example, input devices may include input mechanisms, such as a microphone, input elements, a display, etc. Output devices may include mechanisms for outputting data in audio, video and / or hard copy format. For example, output devices may include a speaker, a display, etc.

[0051] In some embodiments, the wireless device UE 110 may comprise a series of modules configured to implement the functionalities of the wireless device described herein. Moreover, in some embodiments, the UE 110 may also comprise means for the functionalities described herein.

[0052] It will be appreciated that the various modules may be implemented as combination of hardware and software, for instance, the processor, memory, and transceiver(s) of UE 110 shown in FIG. 2A. Some embodiments may also include additional modules to support additional and / or optional functionalities.

[0053] FIG. 2B is a schematic diagram of an example of an apparatus for a radio access node 120 or network node 130. The apparatus may comprise at least one processor 220 and at least memory 230 storing computer program instructions that, when executed by the at least one processor 220, cause the apparatus to carry out the embodiments of the network node 130 or radio access node 120 described herein. The example radio access node 120 or network node 130 may include one or more of a transceiver 310, processor 320, memory 330, and network interface 340. In some embodiments, the transceiver 310 facilitates transmitting wireless signals to and receiving wireless signals from wireless devices, such as UE 110 (e.g., via transmitted s) (Tx), receiver(s) (Rx), and antenna(s)). The processor 320 executes instructions to provide some or all of the functionalities described herein as being provided by the radio access node 120 orthe network node 130, the memory 330 stores the instructions executed by the processor 320. In some embodiments, the processor 320 and the memory 330 form processing circuitry. The network interface 340 may communicate signals to backend network components, such as a gateway, switch, router, Internet, Public Switched Telephone Network (PSTN), core network nodes or radio network controllers, etc.

[0054] The processor 320 may include any suitable combination of hardware to execute instructions and manipulate data to perform some or all of the described functions of the radio access node 120 or the network node 130, such as those described herein. In some embodiments, the processor 320 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs) and / or other logic.

[0055] The memory 330 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and / or other instructions capable of being executed by a processor 320. Examples of memory 330 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or or any other volatile or non-volatile, non- transitory computer-readable and / or computer-executable memory devices that store information. For example, the memory 330 includes computer program code causing the processor 320 to perform processing according to the methods described herein, e.g., the method of FIG. 8.

[0056] In some embodiments, the network interface 340 is communicatively coupled to the processor 320 and may refer to any suitable device operable to receive input for the radio access node 120 or the network node 130, send output from the radio access node 120 or the network node 130, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding. The network interface 340 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

[0057] Other embodiments of the radio access node 120 or the network node 130 may include additional components beyond those shown in FIG. 2B that may be responsible for providing certain aspects of the node’s functionalities, including any of the functionalities described herein and / or any additional functionalities (including any functionality necessary to support the solutions described herein). The various different types of radio access nodes ornetwork nodes may include components having the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may represent partly or entirely different physical components.

[0058] Processors, interfaces, and memory similar to those described with respect to FIG. 2B may be included in other nodes (such as UE 110, radio access node 120, etc.). Other nodes may optionally include or not include a wireless interface (such as the transceiver described in FIG. 2B).

[0059] In some embodiments, the radio access node 120 or the network node 130 may comprise a series of modules configured to implement the functionalities of the radio access node 120 or the network node 130 described herein. Moreover, in some embodiments, the radio access node 120 or the network node 130 may also comprise means for the functionalities described herein.

[0060] It will be appreciated that the various modules may be implemented as combination of hardware and software, for instance, the processor, memory, and transceiver(s) of the radio access node 120 or the network node 130 shown in FIG. 2B. Some embodiments may also include additional modules to support additional and / or optional functionalities.

[0061] Before referring to FIGs. 4 to 10 and describing methods of dynamic on-demand SIB1 transmission mode handling according to the disclosure, some background information and aspects related to the subject disclosure will be provided. It should be noted that all concepts described herein, although described, e.g., for one communication direction, e.g., for downlink communication, are applicable for the other direction as well, e.g., in the uplink (UL) communication. Moreover, concepts described for one entity, e.g., a UE 110, are applicable to another entity, e.g., a base station or network node 120, when considering for example another communication direction or another network setting as will be apparent to the skilled person.

[0062] Network energy saving plays an important role in modem communication networks. One approach to save energy is directed to transmission or non-transmission of system information (SI), which is usually broadcasted periodically over an entire cell area to inform UEs about parameters of the network in a continuous manner. The main drawback of this periodic broadcasting is a low energy efficiency, in particular, if a cell is faced with a low load or with no load in the cell (i.e., there are few or no UEs to benefit from the transmitted SI). In the 3 GPP 5th generation (5G) / New Radio (NR) mobile communication system, transmission of system information of other SI than minimum SI may be omitted. Minimum SI relates to information of master information block (MIB) and system information block 1 (SIB 1). The information of SIB2 to SIB19, which carry non-essential SI, may, additionally oralternatively to broadcasting, be provided on demand. MIB and SIB1 are currently still broadcasted regularly in NR to carry basic information required for initial access of the UEs.

[0063] A further enhancement of NES could be to also provide SIB1 only on demand. However, since SIB1 is essential system information for communicating with a cell, the procedures for on-demand SIB2 to SIB 19 may not be applied. Further information flow may be required, such as providing the UE with on-demand SIB1 configuration information carrying information required to receive / request SIB1 information and / or interplay of two different cells.

[0064] Therefore, in some embodiments described herein, the on-demand SIB1 cell is a non-anchor cell (also denoted in this disclosure as capacity cell or CapCell or first cell), in which SIB1 is only provided on-demand. The anchor cell (also denoted in this disclosure as coverage cell or CovCell or second cell) is regularly broadcasting the anchor cell’s SIB1, as per legacy operations. Moreover, the UE is in an idle or inactive mode (RRC IDLE, RRC IN ACTIVE) and camping on the anchor cell. The non-anchor cell refers to a cell that supports on-demand SIB or also denoted as SIBl-less function (without transmitting SIB1) apart from legacy SIB1 operation, where the SIB1 information of the non-anchor cell may be transmitted either via anchor cell or non-anchor cell according to different embodiments described herein.

[0065] In embodiments of the disclosure, the on-demand SIB1 transmission is triggered by a wake-up signal (WUS) or, more generally referred to as on-demand SIB1 request, from the UE, which may be similar to or different from the on-demand SIB request for other SIBs based on physical random access channel (PRACH) in legacy specifications, e.g., as defined in 3GPP TS 38.331 Release 17 or 18. The configuration information of the WUS / on-demand SIB1 request, of the WUS / on-demand SIB1 response and / or for receiving the SIB1 information is provided by the network (NW) to the UEs. The configuration information may be transmitted by the network using one or more messages. For example, a first message may include information for transmitting an on-demand SIB1 request and for receiving an on-demand SIB1 response, and a second message may include information for receiving on-demand SIB1 information. Alternatively, the first message may include information for transmitting an on- demand SIB1 request, the second message information for receiving an on-demand SIB1 response, and the third message information for receiving on-demand SIB1 information.

[0066] Regarding on-demand SIB1 transmission from gNBs to RRC IDLE / INACTIVE UEs, two deployment cases may generally be considered:• Case-A: Co-located anchor and non-anchor cell in the same gNB, where the information exchange between the two cells is via internal interface. The RUs of anchor and non-anchor cells are physically located.• Case-B: Non-co-located anchor and non-anchor cell in different gNBs, e.g., in gNB 120 A and gNB 120B as described with respect to FIG. 1, where the information exchange between the two cells is via a backhaul interface, i.e. an Xn interface. The RUs of anchor and non-anchor cells are physically non-located.

[0067] In the embodiments described herein, the UL on-demand SIB1 request, also called wake-up-signal (WUS), may be received either by the anchor cell or the non-anchor cell. Different scenarios are conceivable for each of cases A and B as are shown in FIG. 3 Since the information transmission between two different gNBs may be more relevant to be defined, case B is (mainly) considered in the following but not limiting the disclosure.

[0068] Scenario 1 : The backhaul signaling of on-demand SIB1 request / WUS configuration may be exchanged between anchor cells 120-2 and non-anchor cells 120-1 (via backhaul for non-co-located case or via internal interface for collocated case). The anchor cell 120-2 may handle the on-demand SIB1 request configuration, herein also denoted as configuration information, to the RRC IDLE / RRC INACTIVE UEs as well as the on-demand SIB1 request reception from the RRC IDLE / RRC INACTIVE UEs. In the meanwhile, the anchor cell 120- 2 may also handle the delivery of on-demand non-anchor cell SIB1 to the RRC IDLE / RRC INACTIVE UEs based on the exchanged information via backhauling. From network energy saving perspective, in this case, the non-anchor cell 120-1 could achieve the best network side energy saving performance because of the only network side energy consumption is for information exchange of backhauling. This case does not require UE 110 switching between anchor cell 120-2 and non-anchor cell 120-1 for acquiring the on-demand SIB1.

[0069] Scenario-2: The anchor cell 120-2 may trigger the non-anchor cell 120-1 to send the on-demand SIB1 by non-anchor cell 120-1 itself. The anchor cell 120-2 may then handle the transmission of on-demand SIB1 request configuration to the RRC IDLE / RRC INACTIVE UEs as well as the on-demand SIB1 request reception from the RRC IDLE / RRC INACTIVE UEs. This case requires UE 110 switching between anchor cell 120-2 and non-anchor cell 120-1 for acquiring the on-demand SIB1 since the non-anchor cell's SIB1 is transmitted from the non-anchor cell 120-1 itself.

[0070] Scenario-3: The anchor cell 120-2 only handles the on-demand configuration to the RRC IDLE / RRC INACTIVE UEs, e.g. the information of on-demand SIB1 requestconfiguration may be exchanged via backhauling beforehand for non-collocated case. And the non-anchor cell 120-1 may then handle the on-demand reception from the RRC IDLE / RRC IN ACTIVE UEs as well as the transmission of on-demand SIB1 by itself. This case requires the non-anchor cell 120-1 to monitor for on-demand SIB1 request / WUS reception, which increases the energy consumption for non-anchor cell 120-1 compared to scenarios 1 and 2. This case requires UE 110 switching between anchor cell 120-2 and non- anchor cell 120-1 for acquiring the on-demand SIB1.

[0071] Scenario-4: The operation of on-demand SIB1 is independent from the anchor cell 120-2. The non-anchor cell 120-1 may handle the on-demand SIB1 request configuration to the RRC IDLE / RRC INACTIVE UEs as well as the on-demand SIB1 request reception from the RRC IDLE / RRC INACTIVE UEs. In the meanwhile, the non-anchor cell 120-1 will also handle the delivery of on-demand SIB1 to the RRC IDLE / RRC INACTIVE UEs. This case requires a mechanism to point to UE 110 the on-demand SIB1 request / WUS. This case requires UE 110 switching between anchor cell 120-2 and non-anchor cell 120-1 for acquiring the on- demand SIB 1.

[0072] As explained above, there may be two options regarding transmission of on-demand SIB1 request / WUS configuration.• Optionl : The anchor cell transmits WUS configuration. Practically, it may be assumed that the anchor cell provides the IDLE mode functions for camping and initial access. The common signals / channels including synchronization signal block (SSB / SIB / paging / random access channel (RACH) may be transmitted to or received from the RRC IDLE / RRC INACTIVE UEs camping on this cell. Thus, the anchor cell may be used also to transmit the on-demand SIB1 WUS configuration to UE. The on-demand SIB1 request configuration may be added as part of system information, in MIB, SIB1, any of SIB 2 to SIB 19, or any other, possibly newly defined SIB of the anchor cell.• Option 2: The non-anchor cell transmits WUS configuration. As explained for scenario-4, the non-anchor cell may provide SSB transmission, as well as on- demand SIB1 transmission, by itself. In this case, the on-demand SIB1 WUS configuration must be delivered to the RRC IDLE / RRC INACTIVE UEs by the non-anchor cell itself.

[0073] Generally, in legacy operations, a first message for RRC IDLE / INACTIVE UEs to communicate with NW is sending of UL PRACH signal. In addition, in legacy operations for RRC IDLE / RRC INACTIVE UEs requesting the on-demand SIB(s) other than SIB1information, it is also required for the RRC IDLE / RRC INACTIVE UEs to perform PRACH transmission as requesting indication to receive on-demand SIBs. To align with the legacy operation for on-demand SIB operation, PRACH may be used as on-demand SIB 1 request for triggering of on-demand SIB1 transmission for RRC IDLE / RRC INACTIVE UEs.

[0074] The UL on-demand SIB1 request / WUS may be transmitted towards and received from either the anchor cell or the non-anchor cell. Practically, monitoring of on-demand SIB1 request may cause extra network energy consumption with network reception. But on the other hand, it allows the non-anchor cell to operate the on-demand SIB1 request independently from the anchor cell, i.e., without the need of backhaul signaling back and forth.

[0075] The on-demand SIB1 may be delivered to the RRC IDLE / RRC IN ACTIVE UE either via anchor cell (as described for scenario- 1) or non-anchor cell (as described for scenarios-2 / 3 / 4). For the delivery of on-demand SIB1 via anchor cell, it may be added and delivered as part of the system information of anchor cell. And for the delivery of on-demand SIB1 via non-anchor cell, it may be either triggered by anchor cell via backhaul signaling or it may be performed in a configuration manner by non-anchor cell itself.

[0076] In the most straight forward attempt for supporting acquisition of on-demand SIB1 information, the on-demand SIB1 information may be provided by returning to legacy SIB1 transmission to the requesting UE(s). However, this approach is inflexible and different SIB1 transmission modes may be provided to support different situations determined at the network side, e.g., for the non-anchor cell.

[0077] The SIB1 transmission mode may depend on different factors such as the number of UEs requesting the on-demand SIB1 transmission or benefiting from the SIB1 transmission or estimated need from UEs based on WUS reception. In some examples, UE capabilities and / or radio coverage conditions can be implicitly provided through, e.g., a selected preamble / PRACH resources as WUS / on-demand SIB1 request or a Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) level of the WUS / on-demand SIB1 request received at the gNB. This may impact the SIB1 transmission mode selected by the cell. For instance, a UE in poor radio conditions (e.g. at cell edge) may require more than one SIB1 transmission to successfully acquire SIB1 (i.e. the gNB may consider use of repetitions for SIB1 transmission).

[0078] In this disclosure, methods and systems for enabling a dynamic handling of on- demand SIB1 transmission modes are provided and respective UE and network behavior is disclosed. Two stages are considered: Stage 1 relates to the network (e.g., gNB providing a cell) deciding which on-demand SIB1 transmission mode to be used for transmitting SIB1 in a cell,which does not periodically and continuously broadcast SIB1. Stage 2 then relates to informing the UE about the SIB1 transmission mode to be used.

[0079] For example, there may be four possible transmission modes (or combination of those) defined, such as:• Mode#l : Regular SIB 1 transmission mode as per legacy, i.e., resuming periodic SIB 1 broadcast.• Mode#2: Time-confined regular SIB1 transmission, e.g., resuming periodic SIB1 broadcast for a defined time period or time window "T".• Mode#3: Repeated SIB1 transmission, i.e., "N" repetitions in time with a specified pattern (N > 1).• Mode#4: Postposed SIB1 transmission by a time offset "O", e.g., combined with any of modes mode#l to mode#3.

[0080] Selection criteria of the SIB1 transmission mode may be based on the current and / or expected traffic in the cell within a certain time duration (e.g. number of UEs supporting on- demand reception of SIB1 or number of legacy UEs) or the sum of the latter two, a traffic type, and the like. The estimated traffic (volume, type, UEs etc.) may be determined by machine learning algorithms using historical data on cell activity, as well as from network observations or measurements.

[0081] In one example, if the number of UEs (including legacy UEs) is expected to increase within a certain time of the day, the mode#l (back to legacy SIB1 transmission mode) is more suitable because the cell will be visible to all, i.e., also legacy UEs, which can, thus, also camp on the cell and initiate service. Likewise, when the number of UEs (including legacy UEs) is expected to be low / static, the cell can revert back to the on-demand SIB1 mode. This may happen during the daytime in a residential area, when most people are at work or elsewhere.

[0082] Any of the SIB1 transmission modes can be configured to the UE along with / within the WUS configuration. Alternatively, it can be signaled dynamically by the cell providing SIB1, i.e., in response to the WUS reception.

[0083] In one example, the NW would indicate to the UE the whether the cell is back to legacy mode of operation. The indication, in the following also referred to assistance information, could be in a form of a flag, when present, the UE is instructed to reacquire MIB which includes SIB 1 -related information, as per legacy behavior.

[0084] In another example, the assistance information defines monitoring occasions for the first SIB1 transmission and its (N-l) repetitions, if configured. The N SIB1 transmission occasions are provided to the UE with respect to a certain pattern defining time / frequencyresources, in which SIB1 is expected to be scheduled by the cell. The pattern may be a periodic pattern indicated by a periodicity or another aperiodic transmission pattern indicated, e.g., by a bitmap.

[0085] In another example, the assistance information defines monitoring occasions within a time window T, in which SIB1 transmission is expected. If the first SIB1 is not received successfully, the UE can continue monitoring for SIB1 transmission within the configured time window, e.g., with a specific periodicity t or any other transmission pattern p.

[0086] In another example, the assistance information defines a time offset O starting e.g., from the transmission time of the assistance information or another point in time, e.g. start of new transmission window (frame, subframe, slot etc.). The UE may then know when to start monitoring for SIB1 transmission, e.g., according to legacy periodic transmission, a transmission pattern, a number of repetitions, and the like.

[0087] Assistance information comprised by the cell response to the received WUS, e.g., the on-demand SIB1 (request) response, will overwrite one or more transmission parameters of any assistance information of configured SIB1 transmission modes provided in the WUS configuration, e.g., the configuration information as described in the following. Hence, the configuration information and / or the on-demand SIB 1 response can indicate the use of the time window, the repetitions, the time offset (if any and if combined with other modes), etc. as proposed above. For example, the configuration information may provide a full configuration of all transmission parameters required to receive SIB1 information and the on-demand SIB1 response may provide a kind of delta configuration for overwriting and / or adding some of the transmission parameters provided in the configuration information. In some examples, the on- demand SIB1 response may also define a complete set of transmission parameters, i.e., a new full configuration, replacing the transmission parameters provided in the configuration information. In some examples, receiving the on-demand SIB1 response may also lead to cancelling / discarding all transmission parameters, which represents a stopping of the WUS mode of operation, and subsequently switching to normal SIB1 mode (without on-demand SIB! and without power savings).

[0088] The cell receiving the on-demand SIB1 request, transmitting the on-demand SIB1 response and / or providing the on-demand SIB1 information can be the coverage or the capacity cell. In some examples described herein, the on-demand SIB1 request (WUS) can be in a form of a PRACH preamble (MSG1) and the on-demand SIB1 response to the received WUS may be a RAR (MSG2) of a 4-message random access procedure. Alternatively, the on-demand SIB1 request may be a MSG3 and the on-demand SIB1 response may be a MSG4 in the 4-message random access procedure. Yet alternatively, the on-demand SIB1 request may be a MSGA and the on-demand SIB1 response may be a MSGB in a 2-message random access procedure.

[0089] Now turning to FIGs. 4 to 6, which illustrate different possible information transfer scenarios according to the disclosure. In these examples, a UE 110, which may correspond to the UEs 110 as described with respect to FIG. 1, is in communication with a cell of a network entity 120, such as gNBs 120A and gNB 120B of FIG. 1. The cell can be either a non-anchor cell 120-1 or an anchor cell 120-2 as described with respect to FIG. 3. In the following, the examples consider the non-anchor cell 120-1 to transmit all messages but, as is apparent to the skilled person, at least some of the messages may be transmitted by the anchor cell 120-2 in accordance with the scenarios-1 / 2 / 3 / 4 described above.

[0090] In the most basic example as shown in FIG. 4, the non-anchor cell 120-1, which is in on-demand SIB1 mode transmits assistance information for a SIB1 transmission mode to the UE 110 as is shown with arrow 410. The UE 110 therewith knows how to receive the SIB1 information and receives the SIB1 information accordingly, which is shown with arrow 420.

[0091] The assistance information may be comprised by on-demand SIB1 configuration information sent before the UE 110 transmits its on-demand SIB1 request. Additionally or alternatively, the assistance information may be comprised by the on-demand SIB1 response as is described in detail with respect to Figs. 7 to 10 below.

[0092] The SIB1 transmission mode may be at least one of a regular periodic SIB1 transmission, a SIB1 transmission in a defined time-period, a number of SIB1 transmissions with a specified transmission pattern, and a SIB1 transmission start postponed by a time offset. The assistance information may indicate the SIB1 transmission mode (e.g., using a predefined number for each SIB1 transmission mode) and / or comprise information related to one or more transmission parameters of the SIB1 information, such as, e.g., one or more of a time-period, a periodicity, a number of repetitions, a specified transmission pattern, and a time offset before start of SIB1 transmission. The information related to one or more transmission parameters may also be a flag that indicates to use the transmission parameters provided in MIB or the like.

[0093] The SIB1 transmission mode and / or the one or more transmission parameters may be selected by the network, e.g., the base station providing the anchor cell 120-2 or the non- anchor cell 120-1, based on at least one of a current traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE 110.

[0094] For example, the non-anchor cell 120-1 may decide to return to legacy behavior and indicate the presence of SIB1 in MIB. The SIB1 periodicity may be standardized, e.g., asdefined in TS 38.331, as per legacy. The decision to return back to legacy mode may depend on the number of on-demand SIB1 requests received from one / multiple UEs 110 during an observation period and may, thus, be a cell-specific parameter. In one example, if the cell 120- 1 (or 120-2 as said before) receives a total number of on-demand SIB1 requests from different UEs 110 for requesting SIB1 transmission that exceeds a (possibly network-specific) threshold, e.g., 2, 3, 4, . . ., during an observation period, which may start at the reception of the first on- demand SIB1 request, the cell 120-1 decides to disable the SIB1 on-demand operations and return back to legacy mode of operation, i.e., with regular SIB1 transmissions, as the expected NES gain from providing SIBl-on demand has been seen to decrease due to frequent requests and responses with SIB1 transmissions.

[0095] The threshold on the number of on-demand SIB1 requests should not be set too low so that the switch to regular SIB1 transmission does not happen shortly after the switch to on- demand SIB1 mode and should not be too high, too. For example, the threshold should be set such that UEs 100 can discover the cell 120-1 that did not receive SIB1 before in a reasonable time in order to enable the UEs 110 to camp and to initiate service in the cell 120-1.

[0096] When the cell 120-1 is switched to regular SIB1 transmission mode, it can switch again to on-demand SIB1 mode based on pre-defined, configured or otherwise indicated rules. For example, if the load in the cell 120-1 decreased below a certain threshold, the cell 120-1 can return to on-demand SIB1 transmission mode.

[0097] In another situation, the cell 120-1 may decide to perform N SIB1 transmissions (repetitions). The number N may be a cell-specific and flexibly adjustable parameter that may depend on the radio conditions of the requesting UE 110. The current radio conditions can be indicated by the UE 110 based on, e.g., a selected preamble or selected PRACH resources corresponding to a coverage level or radio conditions measured. The current radio conditions may be indicated explicitly to the cell 120-1, e.g., by a mapping from RSRP / RSRQ to a number of bits, in a MSG3 transmission if msg3 transmission is applied for the on-demand SIB1 procedure. The current radio conditions may alternatively or additionally be inferred by the cell 120-1 based on the received on-demand SIB1 request.

[0098] If the UE 110 is determined in good radio coverage, a single SIB1 transmission would be sufficient; otherwise, multiple SIB1 transmissions would be scheduled to ensure its good reception by the UE 110. The repetition of SIB1 in time may be performed with respect to a pre-defined pattern. In one example, the pattern could be defined by a periodicity “f ’ that may take values from current spec or not, e.g., SIB1 repetitions can exceed the 160 ms. Thevalue of N should be reasonably chosen to avoid losing the NES gain from enabling this on- demand-SIBl mode.

[0099] This repetition mode of is advantageous in terms of NES gain when a single / few on-demand SIB1 requests are received; So the cell 120-1 would reply with N SIB1 without switching back to regular SIB1 transmission mode. The approach is also advantageous when the requesting UE 110 is in poor radio conditions as noted above.

[0100] In another scenario, the cell 120-1 may enable regular SIB1 transmissions but only in a time window “T”. The time window length is cell-specific parameter that may depend on the radio conditions of the requesting UE 110. The radio conditions are indicated to the cell 120-1 as explained above. The SIB1 periodicity t within the time window T (t < T) could be based on regular SIB1 periodicity indicated in the last SIB1 provided by the network before switching to on-demand SIB1 mode or provided as an additional parameter “t” that that can take values from current standard documents or not, e.g., SIB1 repetitions can exceed the 160 ms.

[0101] The SIB1 periodicity may also be based on the legacy specification, where it is linked to the SSB periodicity (e.g., as in clause 5.2.1 of TS 38.331) :The SIB1 is transmitted on the DL-SCH with a periodicity of 160 ms and variable transmission repetition periodicity within 160 ms as specified in TS 38.213, clause 13. The default transmission repetition periodicity of SIB1 is 20 ms but the actual transmission repetition periodicity is up to network implementation. For SSB and control resource set (CORESET) multiplexing pattern 1, SIB1 repetition transmission period is 20 ms. For SSB and CORESET multiplexing pattern 2 / 3, SIB1 transmission repetition period is the same as the SSB period (TS 38.213, clause 13).

[0102] In another scenario, the cell 120-1 providing the SIB1 may indicate to the UE 110 that, e.g., the SIB 1 request was received but that the SIB 1 transmission is postponed by an offset O. The cell 120-1 may also indicate a time window where the SIB 1 transmission will take place starting at an earliest point of transmission according to O. The indication, i.e., comprised by the assistance information, may be a guarantee of transmission or an expected transmission (e.g., cell 120-1 or the network entity 120 in general may decide to further postpone the transmission). The UE 110 will then monitor for downlink control information (DCI) in physical downlink control channel (PDCCH) scheduling the SIB1 according to the time indication from the cell 120-1. The UE 110 may also be not allowed to repeat SIB1 requests until the time offset O (plus possible a reception time) as indicated by the cell is reached.

[0103] In this example, if the cell 120-1 decides to postpone the SIB1 transmission, the cell's 120-1 acknowledgement of receiving the on-demand SIB1 request can be a simpleacknowledgment, i.e., ACK-type transmission using the DCI. If the DCI does not schedule the SIB1 or indicates non-acknowledgment, i.e., NACK, the UE may know, based on prior configuration, that the SIB1 transmission is postponed. Hence, the assistance information indicating the SIB1 transmission mode can be the reception of ACK or NACK as explained above.

[0104] This postponement approach may be applied when the number of requesting UEs 110 is too low and the SIB1 transmission to several UEs 110 is postponed until it is expected that more UEs than a threshold number have sent their SIB1 request. This estimation of number of UEs 110 to determine the value of the offset may be determined by machine learning approaches. For example, the cell 120-1 may decide that the SIB1 is not transmitted until at least 4 UEs 110 have requested the SIB1, leading to an offset of 500 ms or the like depending on the location, time of the day, etc. of the base station providing the cell 120-1.

[0105] FIG. 5 depicts an example of when the assistance information is provided in the on- demand SIB1 response, which is sent in response to the on-demand SIB1 request. In detail, the UE 110 transmits the on-demand SIB1 request as shown with arrow 510 to the cell 120-1. As explained above, information on how to transmit the on-demand SIB1 request to the cell 120- 1 may be received by the UE 110 in configuration information sent, e.g., from the capacity cell 120-1 or the coverage cell 120-2 in broadcast or paging information but may also be provided otherwise.

[0106] The cell 120-1 then responds with the on-demand SIB1 response as shown with arrow 520. The on-demand SIB1 response may in this example comprise the assistance information indicating the SIB1 transmission mode. Hence, the UE 110 receives information on one or more transmission parameters (e.g., how they are set or which parameters to apply) in the on-demand SIB1 response. Finally, the UE 110 receives the SIB1 information according to the assistance information received within the on-demand SIB1 response as shown with arrow 530.

[0107] FIG. 6 relates to an example, in which the assistance information is provided in on- demand SIB1 configuration information and in the on-demand SIB1 response. In this example, the UE 110 receives configuration information related to acquisition of SIB1 information of the cell 120-1, which is shown with arrow 610. The configuration information comprises information for transmitting an on-demand SIB1 request, for receiving an on-demand SIB1 response and for receiving on-demand SIB1 information, which may comprise assistance information indicating a SIB1 transmission mode as explained above.

[0108] The information for transmitting an on-demand SIB1 request may include an indication related to a preamble group or set usable to select a preamble for the on-demand SIB1 request. The preamble group or set may be different from a preamble group or set useable to select a preamble for a SIB2 to SIB 19 request as known in the art. For example, in current 3GPP TS 38.321 specification (e.g., Release 17 or 18), an information element ra- PreambleStartlndex is defined for indicating the start index of preambles for requesting SIB2 to SIB 19. For further indicating the start index of preambles for requesting SIB1, two information elements ra-PreambleStartlndexl and ra-PreambleStartIndex2 may be defined for requesting SIB2 to SIB 19 and SIB1, respectively.

[0109] In some examples, the information for transmitting an on-demand SIB1 request may include an indication related to a RACH resource or occasion usable to select a resource or occasion for the on-demand SIB1 request, wherein the RACH resource or occasion is different from a RACH resource or occasion useable to select a RACH resource or occasion for an on-demand SIB2 to SIB 19 request. Additionally or alternatively, the network may configure different preambles and / or resources for different UEs, e.g., legacy UEs (e.g., up to Release 18) may have different RACH resources / occasions / preambles configured than on-demand SIB1 capable UEs (e.g., Release 19). Therefore, the network will know according to the selected RACH resources / occasions / preambles, which type of UE is requesting the SIB1 information. Typically, legacy UEs will not be able to acquire configuration information and, thus, not able to send the on-demand SIB 1 request for requesting SIB 1.

[0110] The cell 120-1 then receives from the UE 110 the on-demand SIB1 request, e.g., a specific preamble or PRACH resources that indicate that the UE requests on-demand SIB1 request or an explicit request comprised by MSGA or MSG3. This is shown with arrow 620. In response to that, the cell 120-1 transmits the on-demand SIB1 response to the UE 100 as shown with arrow 630. The on-demand SIB1 response again comprises assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE.[OHl] In this example, if the configuration information and the on-demand SIB1 response both comprise transmission parameters of the assistance information indicating a SIB1 transmission mode and comprising information relating to the transmission parameter(s), the UE selects the SIB1 transmission mode and the assistance information as indicated in the on- demand SIB1 response as SIB1 transmission mode for acquiring the SIB1 information. Hence, the assistance information provided in on-demand SIB1 response overwrites at least part of the previous (pre-configured) information provided in the configuration information and the UE110 receives the SIB1 information according to the assistance information received within the on-demand SIB1 response as shown with arrow 640. Of course, configuration information may comprise more information than only the assistance information for receiving the on-demand SIB 1. Therefore, the UE 110 may receive the on-demand SIB 1 response based on (at least some parts of) the configuration information and the assistance information received with the on- demand SIB 1 response.

[0112] In other words, the configuration information may include values of the one or more transmission parameters to be used for SIB1 acquisition by the UE and the assistance information may include a modification of at least one transmission parameter of these (or preconfigured) transmission parameters. The modification of at least one transmission parameter may include at least one of overwriting one or more transmission parameters of the one or more transmission parameters to be used for SIB1 acquisition received within the configuration information and adding at least one transmission parameter to the one or more transmission parameters to be used for SIB1 acquisition received within the configuration information. In these examples, the UE 110 may determine whether the assistant information includes a modification of at least one transmission parameter of the configuration information, and, if so, the UE 110 may modify the corresponding transmission parameter(s) and receive the SIB1 information based on the modified transmission parameter(s) of the assistant information and the transmission parameters of configuration information that were not modified.

[0113] FIG. 7 presents a flow chart of a method performed by a user equipment 110 according to the disclosure. The UE 110, which is in radio resource control, RRC, idle or inactive mode and needs to receive system information block 1, SIB1, information of a cell 120-1 operating in an on-demand SIB1 mode, receives (block 710) configuration information related to acquisition of SIB1 information of the cell 120-1. The configuration information comprises information for transmitting an on-demand SIB1 request, for receiving an on- demand SIB1 response and for receiving on-demand SIB1 information, i.e., it enables the UE 110 to acquire on-demand SIB1 from the cell 120-1.

[0114] In response to transmitting (block 720) the on-demand SIB1 request for acquiring SIB1 information of the cell, the UE 110 receives (block 730) the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode. The assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE.

[0115] The one or more transmission parameters may comprise one or more of a timeperiod, a periodicity, a number of repetitions, a specified transmission pattern, and a time offsetbefore start of SIB1 transmission. The SIB1 transmission mode may be at least one of a regular periodic SIB1 transmission, a SIB1 transmission in a defined time-period, a number of SIB1 transmissions with a specified transmission pattern, and a SIB1 transmission start postponed by a time offset. The SIB1 transmission mode and / or the one or more transmission parameters may have been selected by the cell 120-1 based on at least one of a current traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE. The current radio conditions of the UE 110 may be indicated by the on- demand SIB 1 request.

[0116] The on-demand SIB1 request may be a first message, MSG1 or MSGA, or a third message, MSG3, in a random access procedure. The on-demand SIB1 response may be a second message, MSG2 or MSGB, or a fourth message, MSG4, in a random access procedure. Finally, the UE 110 receives (block 740) the SIB1 information according to the configuration information and the assistance information.

[0117] FIG. 8 presents a flow chart of a method performed by the network entity according to the disclosure. The UE 110 is in radio resource control, RRC, idle or inactive mode and needs to receive system information block 1, SIB1, information of a cell 120-1 operating in an on- demand SIB1 mode. The network entity 120 may be a base station, such as gNB 120A or gNB 120B. The network entity 120 transmits (block 810) configuration information related to acquisition of SIB1 information of the cell 120-1. The configuration information comprises information for transmitting an on-demand SIB1 request, for receiving an on-demand SIB1 response and for receiving on-demand SIB1 information, i.e., it enables the UE 110 to acquire on-demand SIB1 from the cell 120-1.

[0118] In response to receiving (block 820) the on-demand SIB1 request for acquiring SIB1 information of the cell, the network entity 120 (e.g., via cell 120-1 or cell 120-2 as described above) transmits (block 830) the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode. The assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE.

[0119] The one or more transmission parameters may comprise one or more of a timeperiod, a periodicity, a number of repetitions, a specified transmission pattern, and a time offset before start of SIB1 transmission. The SIB1 transmission mode may be at least one of a regular periodic SIB1 transmission, a SIB1 transmission in a defined time-period, a number of SIB1 transmissions with a specified transmission pattern, and a SIB1 transmission start postponed by a time offset. The SIB1 transmission mode and / or the one or more transmission parameters may have been selected by the network entity 120, e.g., for the cell 120-1 based on at least one of acurrent traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE. The current radio conditions of the UE 110 may be indicated by the on-demand SIB1 request.

[0120] The on-demand SIB1 request may be a first message, MSG1 or MSGA, or a third message, MSG3, in a random access procedure. The on-demand SIB1 response may be a second message, MSG2 or MSGB, or a fourth message, MSG4, in a random access procedure. Finally, the network entity 120 transmits (block 840) the SIB1 information according to the configuration information and the assistance information.

[0121] FIG. 9 shows a message flow diagram of handling dynamic on-demand SIB1 transmission modes according to the disclosure. The example is based on that the capacity cell 120-1, e.g., of gNB 120B as described above transmits the shown messages. However, as already explained above, at least some of the messages may be transmitted to the coverage cell 120-2 of gNB 120A. Also, both cells may be provided by one gNB 120 (not shown). Hence, the examples of Fig. 9 showing messages from / to the cell 120-1 only are of a non-limiting nature.

[0122] As depicted in box 900, the cell 120-1 is in on-demand SIB1 mode, i.e., SIB1 is not broadcasted periodically. For example, ssb-subcarrierOffset (Kssb) IE of MIB may be set to a value higher than 23 (resp. 11) for FR1 (resp. for FR2) to indicate to UE 110 that control resource set zero for TypeO-PDCCH common search space is not present, i.e., SIB1 is not broadcasted. Such an indication is depicted with arrow 901. The UE 110 then obtains on- demand SIB1 configuration information as shown with arrow 902. This information may in some embodiments also comprise assistance information, e.g., a flag for legacy mode, a repetition parameter N, a pattern (i.e., periodicity or other pattern) for receiving SIB1, a time window W, and / or a time offset O). The assistance information indicates the SIB1 transmission mode and give further information, which transmission / reception parameters to be used.

[0123] The UE 110 may - at least after reception of the on-demand SIB1 configuration - be in RRC IDLE or RRC INACTIVE mode as shown in box 903. Hence, the UE 110 may receive the messages 901 and 902 still in RRC CONNECTED mode and then transition to RRC IDLE or RRC INACTIVE mode. Alternatively, the UE 110 may have been in RRC IDLE or RRC INACTIVE mode before receiving the messages 901 and 902. Therefore, at least message 902 may be transmitted over the coverage cell 120-2.

[0124] The UE 110 then transmits the on-demand SIB1 request, e.g., according to information received in on-demand SIB1 configuration. This is shown with arrow 904. The UE 110 then starts monitoring for reception of on-demand SIB1 response as is shown in box 905. 1The UE 110 may have been informed by the on-demand SIB1 configuration where and when to transmit the on-demand SIB1 request and receive the on-demand SIB1 response. The cell 120-1 then may select or reevaluate (if it was already indicated in the on-demand SIB1 configuration) the SIB1 transmission mode, which will be used for transmitting the SIB1 information. This process performed by the cell 120-1 is depicted with box 906 and has been described above, i.e., how the network entity 120 or the cells 120-1 or 120-2 can determine which SIB1 transmission mode to use. It is noted that not all SIB1 transmission modes described herein may be supported in a wireless communication network. However, for having flexibility, at least two SIB1 transmission modes should be supported, while one of them is indicated to the UE 110 before the UE 110 can acquire the SIB1 information.

[0125] Depending on which SIB1 transmission mode and which transmission parameters therefore are decided to be used by the cell 120-1, the cell 120-1 transmits one of the on-demand SIB1 response messages 907 to 910 to the UE 110. The selection of the SIB1 transmission mode and the assistance information may be based on at least one of a current traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE 110 as has been described above in detail. The differences in the on- demand SIB1 responses may be achieved by providing an information element included in the on-demand SIB1 response, which defines the transmission mode and the respective parameters for the respective transmission mode.

[0126] For example (arrow 907), if the cell 120-1 decided to return to legacy SIB1 transmission mode, i.e., periodically broadcasting SIB1, the cell 120-1 may indicate in the on- demand SIB1 response with a flag that the SIB1 is now broadcasted regularly. In another example (arrow 908), if the cell 120-1 decided to use repetition of SIB1 as transmission mode, the cell 120-1 may indicate in the on-demand SIB1 response a repetition parameter N and a pattern (e.g., periodicity or other aperiodic pattern) for reception of SIB1. In yet another example (arrow 909), if the cell 120-1 decided to transmit SIB1 within a time window T, the cell 120-1 may indicate the time window T (e.g., by indicating a starting symbol or slot and a duration, by indicating explicitly the time window in terms of from transmission unit to transmission unit, or the like) and a pattern (e.g., periodicity or other aperiodic pattern) for reception of SIB1. In yet another example (arrow 910), if the cell 120-1 decided to postpose SIB1 transmission and, in this example, only transmit SIB1 once, the cell 120-1 may only indicate the time offset O in the on-demand SIB1 response.

[0127] It is noted that different combinations of the SIB1 transmission modes are possible. The cell 120-1 may, e.g., indicate a time offset O with a pattern and a time window T, a timeoffset O with legacy operation, or a time offset O without a pattern but with a time window T. In the latter example, the pattern (i.e., periodicity) as pre-defined in standard documents may be used. The skilled person is aware of possible technical sensible combination of the above described transmission modes.

[0128] How the UE 110 receives the SIB1 information after receiving the on-demand SIB1 responses 907 to 910 of FIG. 9, is further explained now with respect to FIG. 10. The first part relates to the cell 120-1 having signaled to the UE 110 that the SIB1 is to be transmitted as in legacy, i.e., broadcasted periodically. The assistance information relates to a flag in the on- demand SIB1 response 907. The UE 110 then starts monitoring for MIB of the cell 120-1. The previous received MIB from the cell 120-1 may have indicated that no SIB1 is currently transmitted as has been explained above. However, the new MIB, which is received with arrow 907-1 will indicate transmission parameters (e.g., periodicity, resources etc.) for receiving SIB 1. According to these transmission parameters, the UE 110 monitors for receiving SIB 1 and finally receives the SIB1 as is shown with arrow 907-2.

[0129] In the second part of FIG. 10, the cell 120-1 indicates in the on-demand SIB1 response 908 a repetition parameter N and a pattern (e.g., periodicity) for receiving SIB1. In this example, the UE 110 starts monitoring for first SIB1 transmission, which is shown with arrow 908-1. If the first SIB1 was not received or could not successfully be decoded, the UE 110 continues to monitor for the next SIB1 transmission 908-2 according to the pattern. If the UE 110 is not able to successfully receive SIB1 after the total of N repetitions, the UE 110 may transmit a new on-demand SIB 1 request.

[0130] The third part is similar to the second part but the cell 120-1 does not indicate a repetition parameter N but a time window T and a pattern in the on-demand SIB 1 response 909. In this example, the UE 110 starts monitoring for first SIB1 transmission 909-1 in the indicated time window T. If the first SIB1 was not received or could not successfully be decoded, the UE 110 continues to monitor for the next SIB1 transmission 909-2 according to the pattern. If the UE 110 is not able to successfully receive SIB1 within the time window T, the UE 110 may transmit a new on-demand SIB 1 request.

[0131] In the last part of FIG. 10, the cell 120-1 sends the on-demand SIB1 response 910 that includes a time offset O for postponing the SIB1 transmission. Only after the time offset O, the UE 110 starts monitoring for reception of SIB1 information and then receives SIB1 in arrow 910-1. In this example, only one SIB1 information is transmitted. This may also be indicated explicitly in the assistance information of on-demand SIB1 response, e.g., by a repetition parameter of 1.

[0132] The herein described procedures may be applied per model or per functionality level (identified by an identifier) or across models or functionalities of a given entity, e.g., as a UE feature. It should be understood that the apparatuses described herein may comprise or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and / or reception. Although the apparatuses have been described as one entity, different modules and memory may be implemented in one or more physical or logical entities.

[0133] It is noted that whilst embodiments have been described in relation to LTE and 5G NR, similar principles may be applied in relation to other networks and communication systems where enforcing fast connection re-establishment is required. Therefore, although certain embodiments were described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.

[0134] It is also noted herein that while the above describes exemplary embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the subject disclosure.

[0135] In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the subject disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the subject disclosure is not limited thereto. While various aspects of the subject disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0136] Example embodiments of the subject disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and / or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computerexecutable components which, when the program is run, are configured to carry outembodiments. The one or more computer-executable components may be at least one software code or portions of it.

[0137] Further in this regard it should be noted that any blocks of the logic flow as in the figures may represent program processes, or interconnected logic circuits, blocks and functions, or a combination of program processes and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media.

[0138] The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), FPGA, gate level circuits and processors based on multicore processor architecture, as non-limiting examples.

[0139] Example embodiments of the subject disclosure may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0140] The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiment of the subject disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this disclosure will still fall within the scope of the subject disclosure as defined in the appended claims. Indeed, there is a further embodiment comprising a combination of one or more embodiments with any of the other embodiments previously discussed.

Claims

Claims:

1. A method performed by a user equipment, UE, in radio resource control, RRC, idle or inactive mode for acquiring system information block 1, SIB1, information of a cell operating in an on-demand SIB1 mode, comprising:- receiving configuration information related to acquisition of SIB1 information of the cell, wherein the configuration information comprises information for transmitting an on-demand SIB 1 request, for receiving an on-demand SIB 1 response and for receiving on-demand SIB 1 information;- in response to transmitting the on-demand SIB 1 request for acquiring SIB 1 information of the cell, receiving the on-demand SIB 1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE; and- receiving the SIB1 information according to the configuration information and the assistance information.

2. The method of claim 1, wherein the one or more transmission parameters comprise one or more of a time-period, a periodicity, a number of repetitions, a specified transmission pattern, and a time offset before start of SIB1 transmission.

3. The method of claim 1 or claim 2, wherein the SIB1 transmission mode is at least one of a regular periodic SIB1 transmission, a SIB1 transmission in a defined time-period, a number of SIB1 transmissions with a specified transmission pattern, and a SIB1 transmission start postponed by a time offset.

4. The method of any one of claims 1 to 3, wherein the SIB1 transmission mode and / or the one or more transmission parameters were selected by the cell based on at least one of a current traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE.

5. The method of claim 4, wherein the current radio conditions of the UE are indicated by the on-demand SIB 1 request.

6. The method of one of claims 1 to 5, wherein the on-demand SIB1 request is a first message, MSG1 or MSGA, or a third message, MSG3, in a random access procedure.

7. The method of any one of claims 1 to 6, wherein the on-demand SIB1 response is a second message, MSG2 or MSGB, or a fourth message, MSG4, in a random access procedure.

8. The method of any one of claims 1 to 7, wherein the configuration information includes values of the one or more transmission parameters to be used for SIB1 acquisition by the UE, and wherein the assistance information includes a modification of at least one transmission parameter of the one or more transmission parameters.

9. The method of claim 8, wherein the modification of at least one transmission parameter includes at least one of overwriting one or more transmission parameters of the one or more transmission parameters to be used for SIB1 acquisition received within the configuration information and adding at least one transmission parameter to the one or more transmission parameters to be used for SIB1 acquisition received within the configuration information.

10. A method performed by a network entity for providing system information block 1, SIB1, information of a cell to a user equipment, UE, in radio resource control, RRC, idle or inactive mode, wherein the cell operates in an on-demand SIB1 mode, comprising:- transmitting configuration information related to acquisition of SIB1 information of the cell, wherein the configuration information comprises information for transmitting an on-demand SIB 1 request, for receiving an on-demand SIB 1 response and for receiving on-demand SIB 1 information;- in response to receiving the on-demand SIB 1 request for acquiring SIB 1 information of the cell, transmitting the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE; and- transmitting the SIB 1 information according to the configuration information and the assistance information.

11. The method of claim 10, wherein the one or more transmission parameters comprise one or more of a time-period, a periodicity, a number of repetitions, a specified transmission pattern, and a time offset before start of SIB1 transmission.

12. The method of claim 10 or claim 11, wherein the SIB1 transmission mode is at least one of a regular periodic SIB1 transmission, a SIB1 transmission in a defined time-period, a number of SIB1 transmissions with a specified transmission pattern, and a SIB1 transmission start postponed by a time offset.

13. The method of any one of claims 10 to 12, wherein the SIB1 transmission mode and / or the one or more transmission parameters are selected by the network based on at least one of a current traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE.

14. The method of claim 13, wherein the current radio conditions of the UE are indicated by the on-demand SIB 1 request.

15. The method of one of claims 8 to 12, wherein the on-demand SIB1 request is a first message, MSG1 or MSGA, or a third message, MSG3, in a random access procedure.

16. The method of any one of claims 10 to 14, wherein the on-demand SIB1 response is a second message, MSG2 or MSGB, or a fourth message, MSG4, in a random access procedure.

17. The method of any one of claims 10 to 16, wherein the configuration information includes values of the one or more transmission parameters to be used for SIB1 acquisition by the UE, and wherein the assistance information includes a modification of at least one transmission parameter of the one or more transmission parameters.

18. The method of claim 17, wherein the modification of at least one transmission parameter includes at least one of overwriting one or more transmission parameters of the one or more transmission parameters to be used for SIB1 acquisition received within the configuration information and adding at least one transmission parameter to the one ormore transmission parameters to be used for SIB1 acquisition received within the configuration information.

19. An apparatus of a user equipment, UE, operating in radio resource control, RRC, idle or inactive mode configured to:- receive configuration information related to acquisition system information block 1, SIB1, information of a cell operating in an on-demand SIB1 mode, wherein the configuration information comprises information for transmitting an on-demand SIB1 request, for receiving an on-demand SIB1 response and for receiving on- demand SIB1 information;- in response to transmitting the on-demand SIB 1 request for acquiring SIB 1 information of the cell, receive the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE; and- receive the SIB1 information according to the configuration information and the assistance information.

20. The apparatus of claim 19, wherein the one or more transmission parameters comprise one or more of a time-period, a periodicity, a number of repetitions, a specified transmission pattern, and a time offset before start of SIB1 transmission.

21. The apparatus of claim 19 or claim 20, wherein the SIB1 transmission mode is at least one of a regular periodic SIB1 transmission, a SIB1 transmission in a defined time-period, a number of SIB1 transmissions with a specified transmission pattern, and a SIB1 transmission start postponed by a time offset.

22. The apparatus of any one of claims 19 to 21, wherein the SIB1 transmission mode and / or the one or more transmission parameters were selected by the cell based on at least one of a current traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE.

23. The apparatus of claim 22, wherein the current radio conditions of the UE are indicated by the on-demand SIB 1 request.

24. The apparatus of one of claims 19 to 23, wherein the on-demand SIB1 request is a first message, MSG1 or MSGA, or a third message, MSG3, in a random access procedure.

25. The apparatus of any one of claims 19 to 24, wherein the on-demand SIB1 response is a second message, MSG2 or MSGB, or a fourth message, MSG4, in a random access procedure.

26. An apparatus of a network entity configured to:- transmit configuration information related to acquisition of system information block 1, SIB1, information of a cell operating in an on-demand SIB1 mode to a user equipment, UE, in radio resource control, RRC, idle or inactive mode, wherein the configuration information comprises information for transmitting an on-demand SIB 1 request, for receiving an on-demand SIB 1 response and for receiving on-demand SIB1 information;- in response to receiving the on-demand SIB 1 request for acquiring SIB 1 information of the cell, transmit the on-demand SIB1 response comprising assistance information for a SIB1 transmission mode, wherein the assistance information comprises information related to one or more transmission parameters to be used for SIB1 acquisition by the UE; and- transmit the SIB 1 information according to the configuration information and the assistance information.

27. The apparatus of claim 26, wherein the one or more transmission parameters comprise one or more of a time-period, a periodicity, a number of repetitions, a specified transmission pattern, and a time offset before start of SIB1 transmission.

28. The apparatus of claim 26 or claim 27, wherein the SIB1 transmission mode is at least one of a regular periodic SIB1 transmission, a SIB1 transmission in a defined time-period, a number of SIB1 transmissions with a specified transmission pattern, and a SIB1 transmission start postponed by a time offset.

29. The apparatus of any one of claims 26 to 28 wherein the SIB1 transmission mode and / or the one or more transmission parameters are selected by the network based on at least oneof a current traffic volume, an expected traffic volume, a current traffic type, an expected traffic type, and current radio conditions of the UE.

30. The apparatus of claim 29, wherein the current radio conditions of the UE are indicated by the on-demand SIB 1 request.

31. The apparatus of one of claims 26 to 30, wherein the on-demand SIB1 request is a first message, MSG1 or MSGA, or a third message, MSG3, in a random access procedure.

32. The apparatus of any one of claims 26 to 31 wherein the on-demand SIB1 response is a second message, MSG2 or MSGB, or a fourth message, MSG4, in a random access procedure.

33. The method of any one of claims 26 to 32, wherein the configuration information includes values of the one or more transmission parameters to be used for SIB1 acquisition by the UE, and wherein the assistance information includes a modification of at least one transmission parameter of the one or more transmission parameters.

34. The method of claim 33, wherein the modification of at least one transmission parameter includes at least one of overwriting one or more transmission parameters of the one or more transmission parameters to be used for SIB1 acquisition received within the configuration information and adding at least one transmission parameter to the one or more transmission parameters to be used for SIB1 acquisition received within the configuration information.

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