Selection of system information block transmission mode

Abstract

Example embodiments of the present disclosure are related to selection of a system information block 1 (SIB1) transmission mode. A method comprises based on detecting a trigger for system information block 1, SIB1, acquisition, determining, by a terminal device, a time duration until a next periodic SIB1 transmission; selecting either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; and initiating SIB1 acquisition according to the selected SIB1 transmission mode.

Description

SELECTION OF SYSTEM INFORMATION BLOCKTRANSMISSION MODEFIELD

[0001] Various example embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage medium for selection of a system information block 1 (SIB1) transmission mode.BACKGROUND

[0002] In communication networks, system information (SI) is an important component that provides user equipment (UE) with necessary network parameters and operational information. System information may include, but is not limited to, cell identification, access parameters, scheduling information, cell reselection and handover parameters, etc. This information allows the UE to correctly select and reselect serving cells, as well as to manage mobility effectively within the network.

[0003] System Information may be divided into master information block (MIB) and a number of system information blocks (SIBs). MIB may contains the fundamental system information in the network, such as the system frame number, subcarrier spacing, synchronization signal block (SSB) subcarrier offset, etc. MIB allows the UE to understand the basic physical layer parameters of the cell. SIBs are message blocks of system information, and each SIB carries a different type of information. For example, SIB1 may include information about the availability and transmission scheduling of other SIBs, as well as other information vital to accessing the network; SIB2 may include cell reselection information related to the serving cell; SIB3 may include cell reselection information related to intra-frequency neighboring areas; and the like.SUMMARY

[0004] In a first aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from a network node, an indication that the network node supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmissionmode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; select either the first SIB1 transmission mode or the second transmission mode for SIB1 acquisition; and initiate SIB1 acquisition according to the selected SIB1 transmission mode.

[0005] In a second aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: transmit, to a terminal device, an indication that the second apparatus supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; transmit SIB1 according to the first transmission mode; and based on a reception of an on-demand SIB1 request from the terminal device, transmit SIB1 to the terminal device according to the second SIB1 transmission mode.

[0006] In a third aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a network node, an indication that the network node supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; selecting either the first SIB1 transmission mode or the second transmission mode for SIB1 acquisition; and initiating SIB1 acquisition according to the selected SIB1 transmission mode.

[0007] In a fourth aspect of the present disclosure, there is provided a method. The method comprises: transmitting, to a terminal device, an indication that the second apparatus supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; transmitting SIB1 according to the first transmission mode; and based on a reception of an on-demand SIB1 request from the terminal device, transmitting SIB1 to the terminal device according to the second SIB1 transmission mode.

[0008] In a fifth aspect of the present disclosure, there is provided a first apparatus.The first apparatus comprises means for receiving, from a network node, an indication that the network node supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on- demand SIB1 transmission mode; means for selecting either the first SIB1 transmission mode or the second transmission mode for SIB 1 acquisition; and means for initiating SIB 1 acquisition according to the selected SIB1 transmission mode.

[0009] In a sixth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for transmitting, to a terminal device, an indication that the second apparatus supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; means for transmitting SIB1 according to the first transmission mode; and means for based on a reception of an on- demand SIB1 request from the terminal device, transmitting SIB1 to the terminal device according to the second SIB1 transmission mode.

[0010] In a seventh aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: receive, from a network node, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode; select, based on the at least one selection criterion, a SIB1 transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode; and initiate SIB1 acquisition according to the selected SIB1 transmission mode.

[0011] In an eighth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus at least to: transmit, to a terminal device, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1transmission modes comprise at least a periodic SIB1 transmission mode and an on- demand SIB1 transmission mode transmit SIB1 according to the periodic transmission mode; and based on a reception of an on-demand SIB1 request from the terminal device, transmit SIB1 to the terminal device according to the on-demand SIBltransmission mode.

[0012] In a ninth aspect of the present disclosure, there is provided a method. The method comprises: receiving, from a network node, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode; selecting, based on the at least one selection criterion, a SIB1 transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode; and initiating SIB1 acquisition according to the selected SIB1 transmission mode.

[0013] In a tenth aspect of the present disclosure, there is provided a method. The method comprises: transmitting, to a terminal device, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on- demand SIB1 transmission mode transmitting SIB1 according to the periodic transmission mode; and based on a reception of an on-demand SIB1 request from the terminal device, transmitting SIB1 to the terminal device according to the on-demand SIBltransmission mode.

[0014] In an eleventh aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for receiving, from a network node, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode; means for selecting, based on the at least one selection criterion, a SIB1 transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode; and means for initiating SIB1 acquisition according to the selected SIB1 transmission mode.

[0015] In a twelfth aspect of the present disclosure, there is provided a second apparatus. The second apparatus comprises means for transmitting, to a terminal device, a configuration indicating at least one selection criterion for a system information block1, SIB1, transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode means for transmitting SIB1 according to the periodic transmission mode; and means for based on a reception of an on-demand SIB1 request from the terminal device, transmitting SIB1 to the terminal device according to the on-demand SIBltransmission mode.

[0016] In a thirteen aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: based on detecting a trigger for system information block 1, SIB1, acquisition, determine a time duration until a next periodic SIB1 transmission; select either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; and initiate SIB1 acquisition with a network node according to the selected SIB1 transmission mode.

[0017] In a fourteenth aspect of the present disclosure, there is provided a method. The method comprises: based on detecting a trigger for system information block 1, SIB ling acquisition, determine a time duration until a next periodic SIB1 transmission; selecting either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; and initiating SIB1 acquisition with a network node according to the selected SIB1 transmission mode.

[0018] In a fifteenth aspect of the present disclosure, there is provided a first apparatus. The first apparatus comprises means for based on detecting a trigger for system information block 1, SIB ling acquisition, determine a time duration until a next periodic SIB1 transmission; means for selecting either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; and means for initiating SIB1 acquisition with a network node according to the selectedSIB1 transmission mode.

[0019] In a sixteenth aspect of the present disclosure, there is provided a computer readable medium. The computer readable medium comprises instructions stored thereon for causing an apparatus to perform at least the method according to any of the third, fourth, ninth, tenth, eighth, or thirteen aspects.

[0020] It is to be understood that the Summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Some example embodiments will now be described with reference to the accompanying drawings, where:

[0022] FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure can be implemented;

[0023] FIG. 2A and FIG. 2B illustrate example OD-SIB1 use cases in which example embodiments of the present disclosure may be implemented;

[0024] FIG. 3 illustrates a signaling flow of selection of SIB1 transmission mode in accordance with some example embodiments of the present disclosure;

[0025] FIG. 4 illustrates a flowchart of a process implemented at the terminal device for selection of a transmission mode in accordance with some example embodiments of the present disclosure;

[0026] FIG. 5 illustrates a flowchart of a process implemented at the terminal device for selection of a transmission mode using the time-based selection criterion in accordance with some example embodiments of the present disclosure.

[0027] FIG. 6 illustrates a timeline showing an example scenario of selection of SIB1 transmission mode in accordance with some example embodiments of the present disclosure;

[0028] FIG. 7 illustrates a signaling flow of selection of SIB1 transmission mode in accordance with some example embodiments of the present disclosure;

[0029] FIG. 8 A illustrates a flowchart of a process for selection of SIB1 transmission mode in accordance with some example embodiments of the present disclosure;

[0030] FIG. 8B illustrates a flowchart of a process for concurrent support of SIB1 transmission modes implemented in accordance with some other example embodiments of the present disclosure;

[0031] FIG. 9A illustrates a flowchart of a method implemented at a terminal device in accordance with some other example embodiments of the present disclosure;

[0032] FIG. 9B illustrates a flowchart of a method implemented at a network device in accordance with some other example embodiments of the present disclosure;

[0033] FIG. 10 illustrates a flowchart of a method implemented at a terminal device in accordance with some further example embodiments of the present disclosure;

[0034] FIG. 11 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure; and

[0035] FIG. 12 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

[0036] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0037] Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. Embodiments described herein can be implemented in various manners other than the ones described below.

[0038] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

[0039] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes 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 affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0040] It shall be understood that although the terms “first,” “second,”..., etc. in front of noun(s) and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another and they do not limit the order of the noun(s). For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0041] As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0042] As used herein, unless stated explicitly, performing a step “in response to A” does not indicate that the step is performed immediately after “A” occurs and one or more intervening steps may be included.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0044] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and / or digital hardware circuit(s) with software / firmware and(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0045] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0046] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G), the sixth generation (6G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodimentsof the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0047] As used herein, the term “network device” or “network node” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low power node such as a femto, a pico, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, an aircraft network device, and so forth, depending on the applied terminology and technology. In some example embodiments, radio access network (RAN) split architecture comprises a Centralized Unit (CU) and a Distributed Unit (DU) at an IAB donor node. An IAB node comprises a Mobile Terminal (IAB-MT) part that behaves like a UE toward the parent node, and a DU part of an IAB node behaves like a base station toward the next-hop IAB node.

[0048] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remotesurgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. The terminal device may also correspond to a Mobile Termination (MT) part of an IAB node (e.g., a relay node). In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0049] As used herein, the term “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing a communication, for example, a communication between a terminal device and a network device, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other combination of the time, frequency, space and / or code domain resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

[0050] FIG. 1 illustrates a schematic diagram of an example communication environment 100 in which example embodiments of the present disclosure may be implemented. In the communication environment 100, a plurality of communication devices, including terminal devices 110-1 to 110-3 and network nodes 120-1 and 120-2, may communicate with each other.

[0051] For purpose of discussion, the terminal devices 110-1 to 110-3 are collectively or individually referred to the terminal devices 110, and the network nodes 120-1 and 120- 2 are collectively or individually referred to the network nodes 120.

[0052] In the example of FIG. 1, the terminal device 110 may be a UE and the network node 120 may be a RAN network node such as a base station / gNB serving the UE. The serving area of a network node 120 may be called a cell. In communication environment 100, the network node 120-1 provides a cell 102 and the network node 120-2 provides a cell 104. Further, in some cases, for power saving purpose, the cell 104 may be operated in the NES mode. If so, the cell 104 also may be call as an NES cell 104 accordingly. Insome cases, the cell 102 may be an anchor cell 102 of the cell 104.

[0053] It is to be understood that the number of devices and their connections shown in FIG. 1 are only for the purpose of illustration without suggesting any limitation. The communication environment 100 may include any suitable number of devices configured to implementing example embodiments of the present disclosure. Although not shown, it would be appreciated that one or more additional devices may be located in the cell, and one or more additional cells may be deployed in the communication environment 100. It is noted that although illustrated as a RAN network node, the network node 120 may be another device than a RAN network node. Although illustrated as UE, the terminal device 110 may be another device than a terminal device.

[0054] In the following, for the purpose of illustration, some example embodiments are described with the terminal device 110 operating as a UE and the network node 120 operating as a base station. However, in some example embodiments, operations described in connection with a terminal device may be implemented at a network device or other device, and operations described in connection with a network device may be implemented at a terminal device or other device.

[0055] In some example embodiments, a communication direction from the network node 120 to the terminal device 110 is referred to as a downlink (DL), while a communication direction from the terminal device 110 to the network node 120 is referred to as an uplink (UL). In DL, the network node 120 is a transmitting (TX) device (or a transmitter) and the terminal device 110 is a receiving (RX) device (or a receiver). In UL, the terminal device 110 is a TX device (or a transmitter) and the network node 120 is a RX device (or a receiver).

[0056] Communications in the communication environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), and the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division MultipleAccess (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0057] System information is divided into the MIB and a number of SIBs, including SIB1, SIB2, SIB3, SIB4, etc. Normally, MIB and SIB1 may be transmitted periodically.

[0058] For example, the MIB may be transmitted on the broadcast channel (BCH) with a periodicity of 80 ms and repetitions made within 80 ms and it includes parameters that are needed to acquire SIB1 from the cell. The first transmission of the MIB is scheduled in some defined subframes and repetitions are scheduled according to the period of SSB.

[0059] In some examples, the SIB1 may be transmitted on the downlink shared channel (DL-SCH) with a periodicity of 160 ms and variable transmission repetition periodicity within 160 ms. The default transmission repetition periodicity of SIB1 may be 20 ms but the actual transmission repetition periodicity is up to network implementation. For example, for SSB and control resource set (CORESET) multiplexing pattern 1, SIB1 repetition transmission period may be set to 20 ms. For SSB and CORESET multiplexing pattern 2 / 3, SIB1 transmission repetition period may be the same as the SSB period. SIB1 may include information regarding the availability and scheduling (e.g. mapping of SIBs to SI message, periodicity, Si-window size) of other SIBs with an indication whether one or more SIBs are only provided on-demand and, in that case, the configuration needed by the UE to perform the SI request. SIB1 is a cell-specific SIB.

[0060] Network energy saving (NES) currently supports frequent system information broadcasting. The on-demand (OD)-SIBl feature is one of the objectives on NES enhancements. In the OD-SIB1 acquisition process, the network provides the terminal device with specific system information only when it requests it. This is in contrast to the periodic broadcasting of SIB Is, which happens irrespective of whether or not the terminal device needs the information at that time. The terminal device may request the SIB1 transmission by transmitting a wake-up signal to the (capacity) cell. The wake-up signal may be expected to be based on the random access channel (RACH) preamble, and the configuration may be provided by a coverage cell of the terminal device. The network may save energy by avoiding or reducing the periodic SIB1 transmissions and insteadonly provide the SIB1 based on the on-demand requests from terminal devices.

[0061] With the OD-SIB1 feature, aNES cell may save energy by enabling less frequent broadcast of the SIB1, as the SIB1 may be broadcasted only when needed, e.g., for the user equipment (UE) to camp on the cell. Radio resource control (RRC) idle / inactive mode UEs, needing SIB1 information from the NES cell, may request this information by means of indicating it via an uplink (UL) wake-up signal (WUS).

[0062] FIG. 2A and FIG. 2B illustrate example OD-SIB1 use cases in which example embodiments of the present disclosure may be implemented. FIG. 2A and FIG. 2B are discussed with reference to FIG. 1. In the examples shown in FIG. 2A and FIG. 2B, it is assumed that the cell 104 operates in an NES mode and the terminal device 110-3 in the cell 104 needs to request for SIB1.

[0063] FIG. 2A illustrates an OD-SIB1 use case where the OD-SIB1 operation is partially assisted by an anchor cell (represented as Cell A), e.g., the cell 102 provided by the network node 120-1. During the OD-SIB1 operation 202, the UL WUS configuration 220 is broadcasted by the Cell A. The terminal device 110-3 sends an UL WUS 222 to the NES Cell 104 provided by the network node 120-2. The NES cell 104 may transmit SIB1 224 upon UL WUS 222 indication forwarded from the Cell A 102 over network interface.

[0064] FIG. 2B illustrates another OD-SIB1 use case where the OD-SIB1 operation is fully assisted by Cell A provided by the network node 120-1. During the OD-SIB1 operation 203, the UL WUS configuration 230 is broadcasted by the Cell A 102. The terminal device 110-3 sends an UL WUS 232 to cell A 102. The Cell A 102 transmits SIB1 234 of the NES cell 104 upon the UL WUS 232 received from the terminal device 110-3.

[0065] It would be appreciated that the examples shown in FIG. 2A and FIG. 2B are provided for the purpose of illustration and there may be various variations for the OD- SIB1 transmission, some of which are provided as below.

[0066] In some example embodiments, more than one Cell A may provide the configuration for the same NES cell. In some example embodiments, the same Cell A may assist more than one NES cell. In some example embodiments, the RRC release message may be used to assist intra-cell WUS.

[0067] In some example embodiments, regarding information of WUS configuration,the physical cell identity (PCI) and the frequency of a NES cell may be used to associate the UL WUS configuration with a NES cell. In some example embodiments, for Message 1 based on-demand SIB1 request, the on-demand SI request configuration that is currently included in SIB1 may be used as the baseline.

[0068] In some example embodiments, regarding transmission of WUS configuration, the SIB of Cell A may be used to configure on-demand SIB1 related configuration for neighbour NES cells, e.g., via new SIB or the existing SIB.

[0069] In some example embodiments, regarding the triggering condition of WUS transmission, if the terminal device chooses the NES cell using legacy intra-frequency or inter-frequency cell re-selection procedure, the terminal device may trigger WUS transmission. In some example embodiments, after the terminal device successfully receives OD-SIB1 for that NES cell and if it is a suitable cell, the terminal device may camp in the NES Cell. If the NES cell updates the SIB1, it can notify the UE about system information (SI) change by paging the terminal device.

[0070] In some example embodiments, if the UE requests SIB1 to perform initial access in the NES cell, the on-demand SIB1 request may be combined with an initial access to perform RRC connection establishment / resume on the NES cell.

[0071] As discussed, there are more than one transmission mode for SIB1, including a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode. In the periodic SIB1 transmission mode, SIB1 may be broadcasted periodically. In some examples, the periodic SIB1 may be broadcasted infrequently. In the on-demand SIB1 transmission mode, the SIB1 may be provided as requested by the terminal device.

[0072] Each of the transmission modes may have benefits in some cases and drawbacks in others. For example, more frequent SIB1 information broadcasting may consume more network energy and generate interference in the network, but at the same time reduce the latency of acquiring the SIB1. On the other hand, on-demand SIB1 provisioning may consume both UE and network energy and generate interference in the network. However, on-demand SIB1 overhead may be needed more in some cases than others.

[0073] Thus, it is desired to provide a solution to maximize network and UE energy savings by supporting the least frequent SIB1 broadcast periodicity possible, e.g. by relying upon on-demand SIB1 when and where appropriate to reduce SIB1 acquisitiondelay; and keeping the number of on demand SIB1 procedures low, e.g. by relying upon periodic broadcast SIB1 when and where appropriate. However, there is a lack of mechanisms for a scenario, where the network utilizes or supports both SIB1 transmission modes at the same time.

[0074] In example embodiments of the present disclosure, some solutions are provided for a scenario wherein the network supports concurrently more than one SIB1 transmission mode. A terminal device may be configured to automatically select which SIB1 transmission mode to utilize for SIB1 acquisition. Methods as disclosed herein provide a balanced trade-off between network and UE energy consumption and SIB1 acquisition latency.

[0075] Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0076] FIG. 3 illustrates a signaling flow 300 of selection of SIB1 transmission mode in accordance with some example embodiments of the present disclosure. For purpose of illustration, the signaling flow 300 will be described with respect to FIG. 1. The signaling flow 300 involves the terminal device 110 and the network node 120 in FIG. 1.

[0077] In the signaling flow 300, the network node 120 transmits (302) an indication that the network node 120 supports a plurality of SIB1 transmission modes including a first SIB1 transmission mode and a second SIB1 transmission mode. Alternatively, or in addition, the network node 120 transmits (302) configuration information indicating at least one selection criterion for a SIB1 transmission mode. That is, the at least one selection criterion may be configured by the network node 120 to the terminal device 110. In an alternative, the at least one selection criterion may be pre-configured to the terminal device 110, e.g., may be pre-known to the terminal device 110 as standardized criteria. Configuration and configuration information may be used interchangeably, where appropriate.

[0078] The terminal device 110 receives (304) the indication that the network node 120 supports a plurality of SIB1 transmission modes including a first SIB1 transmission mode and a second SIB1 transmission mode. Alternatively, or in addition, the terminal device 110 receives (304) configuration information indicating at least one selection criterion for a SIB1 transmission mode.

[0079] Among the plurality of transmission modes, the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on- demand SIB1 transmission mode. As already mentioned above, SIB1 is transmitted periodically in the periodic SIB1 transmission mode, while in the on-demand SIB1 transmission mode, the network node transmits SIB1 upon a request from the terminal device. If it is indicated that the network node 120 operates using these two SIB1 transmission modes, the terminal device 110 may be allowed to select either one of them for SIB1 acquisition from the network node 120.

[0080] Hereinafter, “first SIB1 transmission mode” and “periodic SIB1 transmission mode” may be used interchangeably, and they may be called as “first transmission mode” or “periodic transmission mode” herein for short. Hereinafter, “second SIB1 transmission mode” and “on-demand SIB1 transmission mode” may be used interchangeably, and they may be called as “second transmission mode” or “on-demand transmission mode” herein for short.

[0081] It would be appreciated that in addition to the periodic SIB1 transmission mode and the on-demand SIB1 transmission mode, there may be other transmission modes defined for SIB1 provisioning. The example embodiments of the present disclosure are also applicable to those transmission modes.

[0082] In some example embodiments, the cell of the network node 120 may operate in a NES mode. In some example embodiments, the cell of the network node 120 may be an anchor cell for a NES cell.

[0083] In some example embodiments, the indication that the network node 120 supports the plurality of SIB1 transmission modes (e.g., the first SIB1 transmission mode and the second SIB1 transmission mode) may be received in MIB. That is, MIB may indicate simultaneous activation or enablement or support of the periodic SIBltransmission mode and the on-demand SIB1 transmission mode.

[0084] The terminal device 110 may receive WUS configuration information comprising the indication that the network node 120 supports the plurality of SIB1 transmission modes (e.g., the first SIB1 transmission mode and the second SIB1 transmission mode). The WUS configuration information may be associated with the cell of which SIB1 is needed by the terminal device 110.

[0085] The WUS configuration information may be received from a network node serving the terminal device 110 or another network node (e.g., a non-serving network node). For example, the serving network node of the terminal device 110 may be an NES cell, and the WUS configuration information may be provided by an anchor cell, or more specifically, by a network node of the anchor cell. Some example scenarios are shown in FIG. 2 A and FIG. 2B, where the terminal device 110-3 may receive UL WUS configuration associated with the NES cell 104 from the Cell A 102. As another example, the terminal device 110 may receive the UL WUS configuration from the network node in the NES cell.

[0086] In some example embodiments, the WUS configuration information may include information needed by the terminal device 110 to request for SIB1 in the on-demand SIB1 transmission mode. For example, the WUS configuration information may include the resources for the terminal device to transmit the SIB1 request. For example, the WUS configuration information may include a RACH configuration defining a certain time, frequency, and / or preamble resources to indicate the on-demand SIB1 request.

[0087] In some example embodiments, the WUS configuration information may also include at least one parameter for the periodic SIB1 transmission mode, e.g. the periodicity of SIB1 transmissions (transmission repetition periodicity). The at least one parameter may include at least one of a periodicity of SIB1 transmission, or a system frame number (SFN) offset to locate when SIB1 is transmitted in a radio frame. Scheduling of the SIB1 may be received via downlink control information, DCI.

[0088] In some example embodiments, the parameters for the periodic SIB1 transmission mode may be configured to the terminal device 110 in other ways, such as conveyed in the SSB or MIB transmission from the network node. For example, the periodicity for the periodic SIB1 transmission mode may be indicated in the MIB received by the terminal device 110.

[0089] Still referring to FIG. 3, the terminal device 110 selects (306) one of the plurality of SIB1 transmission modes for SIB1 acquisition. For example, the terminal device 110 selects (306) either the first SIB1 transmission mode or the second transmission mode for SIB1 acquisition. In some example embodiments, the terminal device 110 may detect a trigger for SIB1 acquisition. For example, SIB1 may be needed due to cell reselection, or the terminal device 110 powering on from a cold start. Based on detecting the trigger forSIB1 acquisition, the terminal device 110 may select either the first SIB1 transmission mode or the second SIB1 transmission mode for SIB1 acquisition.

[0090] In some example embodiments, the selecting either the first SIB1 transmission mode or the second SIB1 transmission mode for SIB1 acquisition may be performed based on at least one selection criterion. As mentioned above, the at least one selection criterion may be configured by the network node 120 or is pre-configured to the terminal device 110. The terminal device 110 may use the network-configured or the pre-configured selection criterion / criteria to determine whether to wait for a next periodic SIB1 transmission or request. With the selection criterion / criteria, the terminal device 110 may select a more appropriate SIB1 transmission mode that is suitable for the current scenario of the terminal device as well as the network device. The application of the at least one selection criterion will be described in detail below.

[0091] With the SIB1 transmission mode selected, the terminal device 110 initiates SIB1 acquisition with the network node 120 according to the selected SIB1 transmission mode. As shown in FIG. 3, if the selected SIB1 transmission mode is the first SIB1 transmission mode, the terminal device 110 may monitor (308) for scheduling of periodic SIB1 from the network node 120. If the selected SIB1 transmission mode is the second SIB1 transmission mode, the terminal device 110 may transmit (310) an on-demand SIB1 request to request for SIB 1.

[0092] At the network side, the network node 120 transmits (306) SIB1 according to the first transmission mode. For example, the network node 120 may broadcast SIB1 according to a periodicity configured for the first transmission mode in its cell, so that all terminal device 110s in the cell of the network node 120 may be able to receive the broadcast SIB1 if they determine to apply the periodic SIB1 transmission mode.

[0093] In the periodic SIB1 transmission mode, the configured periodicity of SIB1 may indicate when to monitor for SIB1, e.g. every 160 ms or other periodicity values. The periodicity of SIB1 may be configured to the terminal device 110 in the received WUS configuration information or in any other suitable information provided to the terminal device 110. As the actual scheduling of the SIB1 in terms of time (e.g., symbols) and frequency (e.g., physical resource blocks) resources and the applied modulation & coding scheme (MCS) may be unknown to the terminal device 110, the terminal device 110 may need to monitor for the scheduling of SIB1 from the network node 120 periodically. Theterminal device 110 may obtain the resource parameters when the terminal device 110 receives downlink control information (DCI) in the monitoring occasion. With the resource parameters, the terminal device 110 may detect and acquire the SIB1 broadcasted from the network node.

[0094] Further, if a terminal device 110 selects the second transmission mode and transmits an on-demand SIB1 request, the network node 120 may receive (312) the on- demand SIB1 request. In this case, based on a reception of an on-demand SIB1 request from the terminal device 110, the network node 120 may transmit (314) SIB1 to the terminal device 110 according to the second SIB1 transmission mode. Then the terminal device 110 120 may receive (316) SIB1 from the network node 120 as requested.

[0095] In the on-demand SIB1 transmission mode (the second SIB1 transmission mode), the on-demand SIB1 request may include a wake-up signal, which may be, for example, a random access preamble. As mentioned above, the configuration of the time and frequency resources for this preamble transmission may be included in the WUS configuration information (which may also be called the OD configuration).

[0096] Now it is further discussed some example selection criteria that may be applied for selection of a SIB1 transmission mode by the terminal device.

[0097] FIG. 4 illustrates a flowchart of a process 400 implemented at the terminal device 110 for selection of a transmission mode in accordance with some example embodiments of the present disclosure.

[0098] At block 410, the terminal device 110 may receive, from a network node 120, an indication of concurrent support of periodic SIB1 and on-demand SIB1 transmission modes, which indication may be included in MIB. With such an indication, the terminal device 110 may determine that the network node 120 supports or operates in the plurality of SIB1 transmission modes. The plurality of SIB1 transmission modes may include at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode.

[0099] At block 420, the terminal device 110 receives configuration information including at least one selection criterion for determining of whether the terminal device can use one of the plurality of SIB1 transmission mode. For example, the terminal device 110 may determine whether to use or wait for the periodic SIB1 according to the periodic SIB1 transmission mode, or whether to request for on-demand SIB1 based on the WUSconfiguration according to the on-demand SIB1 transmission mode.

[0100] At block 430, the terminal device 110 detects a trigger for SIB1 acquisition. The terminal device 110 may repeat the detecting of SIB1 acquisition if no trigger is detected. If the trigger for SIB1 acquisition is detected, the terminal device 110 may determine a need for SIB1 and thus at block 450, the terminal device 110 applies the configured selection criterion / criteria to select a SIB1 transmission mode. Based on the SIB1 transmission mode selection, the terminal device 110 may determine if the terminal device 110 uses or waits for the periodic SIB1 or will request for on-demand SIB1. As an alternative, instead of being configured by the network node, the selection criterion / criteria may be pre-configured to the terminal device 110.

[0101] As the terminal device 110 selects among the periodic SIB1 transmission mode and the on-demand SIB1 transmission mode, depending on the selection result, the terminal device 110 may either use or wait for the periodic SIB1 at block 450 A, or request for on-demand SIB1 at block 450B.

[0102] In some example embodiments, the selection criterion / criteria may include a first selection criterion based on at least one time threshold for a time duration until a next periodic SIB1 transmission. The first selection criterion may also be referred to as a timebased selection criterion. In some example embodiments, the time duration may be a duration between the time of triggering SIB1 acquisition and the next periodic SIB1 transmission.

[0103] FIG. 5 illustrates a flowchart of a process 500 implemented at the terminal device 110 for selection of a transmission mode using the time-based selection criterion in accordance with some example embodiments of the present disclosure.

[0104] At block 510, the terminal device 110 detects a trigger for SIB1 acquisition. The terminal device 110 may repeat the detecting of SIB1 acquisition if no trigger is detected.

[0105] If a trigger for SIB1 acquisition is detected, at block 520, the terminal device 110 determines a time duration until a next periodic SIB1 transmission.

[0106] At block 530, the terminal device 110 selects either the first SIB1 transmission mode or the second SIB1 transmission mode based on a comparison result between the time duration and a time threshold. Then at block 540, the terminal device 110 initiates SIB1 acquisition according to the selected SIB1 transmission mode.

[0107] In some example embodiments, the terminal device 110 may receive, from the network node 120, an indication that the network node 120 supports the first SIB1 transmission mode and the second SIB1 transmission mode. Based on the indication, the terminal device 110 may determine to select either the first SIB1 transmission mode or the second SIB1 transmission mode for SIB1 acquisition.

[0108] In some example embodiments, the terminal device 110 may receive, from the network node 120, configuration information indicating a time-based selection criterion to be applied in selecting either the first SIB1 transmission mode or the second SIB1 transmission mode. Alternatively, or in addition, in some example embodiments, the terminal device 110 may receive, from the network node 120, configuration information indicating at least one of the time threshold to be applied in selecting either the first SIB1 transmission mode or the second SIB1 transmission mode. In some other example embodiments, the time-based selection criterion or the time threshold applied in the timebased selection criterion may be pre-configured to the terminal device 110.

[0109] In some example embodiments, if the terminal device 110 determines that the time-based selection criterion is configured by the network or pre-configured for the selecting of either the first SIB1 transmission mode or the second SIB1 transmission mode, the terminal device 110 may determine the time duration until a next periodic SIB1 transmission for the selecting.

[0110] In some example embodiments, based on the time duration until the next periodic SIB1 transmission being below a time threshold, the terminal device 110 may select the first SIB1 transmission mode (i.e., the periodic SIB1 transmission mode). Then the terminal device 110 may monitor for scheduling of periodic SIB1 from the network node according to the periodic SIB1 transmission mode.[OHl] Based on the time duration until the next periodic SIB1 transmission exceeding the time threshold, the terminal device 110 may select the second SIB1 transmission (i.e., the periodic SIB1 transmission mode). Then the terminal device 110 may transmit an on- demand SIB1 request to request for SIB1. The network node 120 may transmit the requested SIB1 to the terminal device 110 upon reception of the on-demand SIB1 request.

[0112] FIG. 6 illustrates a timeline showing an example scenario 600 of selection of a SIB1 transmission mode in accordance with some example embodiments of the presentdisclosure. A plurality of SIB1 in FIG. 6 show periodic SIB1 transmissions. SIB1 transmissions are broadcasted infrequently in the example of FIG. 6 with relatively large periodicity, e.g. 160 ms or more. As shown, at tl, UE1 intends to acquire SIB1 of a cell, but the time duration wl from the time tl to the next SIB1 transmission SI is larger than a time threshold. This is because UE1 just missed the previous periodic SIB1 when UE1 has a need for SIB1 at the time tl. Due to the large periodicity of SIB1, UE1 may request for on-demand SIB1, otherwise UE1 may need a long wait time until the next SIB1.

[0113] It is further assumed that UE1 wants to acquire SIB1 again at the time t2. The time duration w2 from the time t2 to the next SIB1 transmission S2 is small (e.g., smaller than the time threshold). In this case, UE1 may wait for the next SIB1, instead of requesting for on-demand SIB1.

[0114] In some example embodiments, the time threshold applied with the time-based selection criterion may be determined by the terminal device 110 (e.g., up to UE implementation), configured by the network node, or may be pre-configured to the terminal device 110.

[0115] In some cases, by configuring the time threshold, the network node may control the terminal device(s) in its cell to wait and not trigger too many on-demand SIB1 procedures. In some cases, with the application of the time-based selection criterion and with the controlled time threshold, the terminal device 110 may have the flexibility in the selection decision to optimize the SIB1 acquisition procedure with a short delay. In some cases, the terminal device 110 may save its battery life, e.g., by not initiating too many on-demand SIB1 procedures because initiating the on-demand SIB1 procedure may consume more energy for the terminal device than simply monitoring for the periodic SIB1 transmissions. At the network side, the network node may sometimes want to limit the number of on-demand SIB1 in its cell also due to the additional energy consumption.

[0116] In some example embodiments, in addition to the time-based selection criterion or as an alternative, the selection criterion / criteria may include a second selection criterion based on a mobility status of the terminal device 110. The second selection criterion may also be referred to as a mobility -based selection criterion.

[0117] With the second selection criterion, the terminal device 110 may select the first SIB1 transmission mode based on the mobility status of the terminal device 110 being afirst mobility status, or may select the second SIB1 transmission mode based on the mobility status of the terminal device 110 being a second mobility status with a higher mobility level than the first mobility status. The first mobility status may be a low mobility status or a stationary status. The second mobility status may be a high mobility status or a medium mobility status. Mobility statuses have been defined, e.g. in TS 38.304.

[0118] Depending on the mobility of the terminal device 110, its mobility status may include a low mobility status, a normal mobility status, a medium mobility status, or a high mobility status. The mobility status of the terminal device 110 may be determined based on the number of cell reselections during a time period or the variation of radio power measurements. For example, if the number of cell reselections during a time period is less than a first threshold, the mobility status may be determined as the low mobility status or the normal mobility status. If the number of cell reselections during a time period is greater than the first threshold but is less than or equal to a second threshold, the mobility status may be determined as the medium mobility status. If the number of cell reselections during a time period is greater than the second threshold, the mobility status may be determined as the high mobility status.

[0119] A stationary terminal device or a terminal device with low mobility may not be in urgent need of the SIB1, because it is unlikely to perform a cell reselection in the near future. Therefore, if the terminal device 110 has the low mobility status, then the terminal device 110 may wait for the periodic SIB1, even if the SIB1 transmissions are infrequent.

[0120] A terminal device with the medium or high mobility status may be approaching the cell edge soon and in order to perform the related mobility procedure the terminal device 110 may first acquire SIB1 to obtain information on how to acquire SIB2 / SIB3 / SIB4 (the SIBs defining the cell reselection parameters). Therefore, if the terminal device 110 has the medium or higher mobility status, then the terminal device 110 may be allowed to request for on-demand SIB1 to acquire the SIB1 with a lower latency.

[0121] In some example embodiments, the selection criterion of allowing the terminal device with high mobility to select the on-demand SIB1 transmission mode may not be configured for a cell that supports high mobile UEs as too many on-demand SIB1 procedures may be triggered, which may increase the network energy consumption.

[0122] In some example embodiments, the mobility-based selection criterion and the time-based selection criterion may be combined for use in selecting either the periodic SIB1 transmission mode or the on-demand SIB1 transmission mode.

[0123] In some example embodiments, the terminal device 110 may select the periodic SIB1 transmission mode based on the mobility status of the terminal device 110 being a first mobility status and the time duration until the next periodic SIB1 transmission being below a time threshold. For example, if the terminal device 110 has a low mobility status, and the time until the next SIB1 transmission is less than a first time threshold, then the terminal device 110 may wait for the (infrequent) periodic SIB1. In another example, if the terminal device 110 has a high mobility status, and the time until the next SIB1 is less than a second time threshold (which is smaller than the first time threshold), then the terminal device 110 may wait for the (infrequent) periodic SIB1.

[0124] As shown in the example scenario of FIG. 6, it is assumed that UE2 wants to acquire SIB1 at the time t3, e.g., due to cell reselection. The time duration w3 from the time t3 to the next SIB1 transmission S3 is larger than a time threshold, but UE2 is in a low mobility status. In this case, UE2 may wait for the next SIB1.

[0125] In some example embodiments, the terminal device 110 may select the on- demand SIB1 transmission mode based on the mobility status of the terminal device 110 being a second mobility status, or the time duration until the next periodic SIB1 transmission exceeding the time threshold. For example, if the terminal device 110 has a low mobility status, but the time until the next SIB1 transmission is greater than the first time threshold, then the terminal device 110 may be allowed to request for OD-SIB1. In the other example, if the terminal device 110 has a high mobility status and the time until the next SIB1 is more than the corresponding time threshold, then the terminal device 110 may be allowed to request for OD-SIB1.

[0126] In some example embodiments, as an alternative or additionally, the selection criterion / criteria may include a third selection criterion based on at least one radio threshold for a radio metric of the terminal device 110. The third selection criterion may also be referred to as a radio condition-based selection criterion, to rely on the radio condition of the terminal device 110 in the cell for SIB1 transmission mode selection. The terminal device 110 may select the first SIB1 transmission mode based on the radio metric of the terminal device 110 exceeding a radio threshold. In some cases, the terminal device110 may select the second SIB1 transmission mode based on the radio metric of the terminal device 110 being below the radio threshold.

[0127] The radio condition of the terminal device 110 may be measured using any suitable radio metrics, examples of which may include reference signal received power (RSRP), reference signal received quality (RSRQ), a signal to interference plus noise ratio (SINR), and variants thereof.

[0128] If the terminal device 110 is at the cell edge (and thus with a low radio metric), it may need to receive multiple SIB1 repetitions to accumulate sufficient received power for decoding the SIB1 successfully. It may be beneficial to transmit the on-demand SIB1 request to acquire SIB1. In some example embodiments, in response to the on-demand SIB1 request, the network node 120 may transmit the on-demand SIB1 to the terminal device 110 using a more robust transmission scheme (based on the network noticing the on-demand SIB1 request is indicating poor coverage), to allow the terminal device 110 to successfully decode the SIB1. The network device 110 may determine to use the more robust transmission scheme either based on resource selection or the preamble received power in the network node.

[0129] The indication of the poor coverage of the terminal device 110 may be determined based on the Message 1 based indication of coverage enhancement need. For example, the physical random access channel (PRACH) preamble, which is transmitted as an on-demand SIB1 request, may indicate the need for coverage extension, based on which the network node 120 may schedule the number of required SIB1 repetitions accordingly. The number of SIB1 repetitions may be indicated in DCI.

[0130] If the terminal device 110 experiences a bad radio condition (e.g., a low RSRP) and SIB1 is not repeated frequently in the periodic SIB1 transmission mode, the terminal device 110 may request for OD-SIB1 transmission with robust coding. In some cases, the terminal device 110 may be configured by the network node such that if the terminal device 110 detects RSRP is below a threshold (and / or the terminal device 110’s decoding of periodic SIB1 has failed more than a threshold number of times) then the terminal device 110 is allowed to use OD-SIB1.

[0131] In some example embodiments, as an alternative or additionally, the selection criterion / criteria may include a fourth selection criterion based on at least one latencythreshold for a latency requirement of a service, and / or a fifth selection criterion based on at least one quality of service (QoS) threshold for a QoS requirement of a service. The fourth selection criterion may also be referred to as a latency-based selection criterion. The fifth selection criterion may also be referred to as a QoS-based selection criterion.

[0132] In some example embodiments, the terminal device 110 may select the first SIB1 transmission mode based on at least one of the following: the latency requirement of the service exceeding a latency threshold, or the quality of service requirement of the service exceeding a quality of service threshold. The terminal device 110 may select the second SIB1 transmission mode based on at least one of the following: the latency requirement of the service being below a latency threshold, or the quality of service requirement of the service being below a quality of service threshold.

[0133] In some example embodiments, as an alternative or additionally, the selection criterion / criteria may include a sixth selection criterion based on a service type. The sixth selection criterion may also be referred to as a service type-based selection criterion. For example, the service type may be configured as a delay-critical service. The terminal device 110 may select the first (periodic) SIB1 transmission mode based on the terminal device 110 failing to support or be configured with the delay-critical service. The terminal device 110 may select the second (on-demand) SIB1 transmission mode based on the terminal device 110 supporting or being configured with the delay-critical service, so as to obtain SIB1 with a lower latency in some cases.

[0134] In some examples, if the terminal device 110 has pending traffic, potentially with strict latency or QoS requirements (e.g. for ultra reliable and low latency communications, URLLC, service), the terminal device 110 may be allowed to transmit the OD-SIB1 request. In general, the terminal device 110 with the URLLC service or which may need delay-stringent traffic is allowed to trigger OD-SIB1. In some example embodiments, the services or data resource bearers (DRBs) that are eligible for OD-SIB1 may be configured by the network node. In a further embodiment, the terminal device 110 may be allowed select the OD-SIB1 transmission mode if the time until the next periodic SIB 1 transmission exceeds a traffic related threshold, a latency related threshold, or a QoS related threshold.

[0135] In some example embodiments, as an alternative or additionally, the selection criterion / criteria may include a seventh selection criterion based on at least one deviceenergy threshold for a device energy consumption of the terminal device 110. The seventh selection criterion may also be referred to as an energy consumption-based selection criterion. In some example embodiments, the terminal device 110 may select the first SIB1 transmission mode based on a device energy consumption of the terminal device 110 exceeding a device energy threshold. The terminal device 110 may select the second SIB1 transmission mode based on a device energy consumption of the terminal device 110 being below the device energy threshold.

[0136] It would be appreciated that although only the combination of the time-based selection criterion and the mobility -based selection criterion are described above, two or more of the above mentioned selection criteria may be combined together to be applied for selecting a SIB1 transmission mode by the terminal device.

[0137] It would also be appreciated that although some example selection criteria for selecting a SIB1 transmission mode for use are described above, there may be other selection criteria that may be defined and applied to find a balance between network energy consumption and SIB1 acquisition latency.

[0138] In some example embodiments, the terminal device 110 may receive from the network node 120, configuration information comprising a configuration of the at least one selection criterion. Alternatively, or in addition, the terminal device 110 may receive, from the network node 120, configuration information comprising at least one threshold applied with the at least one selection criterion.

[0139] In some example embodiments, the at least one selection criterion and / or at least one threshold applied with the at least one selection criterion to be applicable for the selecting may be determined based on the type or the cause for triggering SIB 1 acquisition by the terminal device 110. In some example, if the cause for triggering SIB1 acquisition is that the terminal device 110 is performing a cell reselection, then the terminal device 110 may apply one or more of the above mentioned selection criteria, with a first set of corresponding thresholds. The first set of thresholds may be set with more relaxed SIB1 acquisition delay as the delay in this case the terminal device 110 may not be so critical as no U-plane may be present. In some other cases, if the cause for triggering SIB1 acquisition is that the terminal device 110 is powering up from cold start, then the terminal device 110 may apply one or more of the above mentioned selection criteria, with a different second set of thresholds. The second set of thresholds may be configured withthe goal to reduce SIB1 acquisition delay.

[0140] In some example embodiments, the at least one selection criterion and / or at least one threshold applied with the at least one selection criterion to be applicable for the selecting may be alternatively or additionally determined based on a device battery status of the terminal device 110, and / or an overheating status of the terminal device 110. For example, if the terminal device 110 is not in a state with low battery life or is not thermally overheating, then the terminal device 110 may be allowed to apply one or more of the above mentioned selection criteria, with a baseline set of thresholds. In some example embodiments, if the terminal device 110 is in a state with low battery life or is thermally overheating, then the terminal device 110 may be allowed to apply one or more of the above mentioned selection criteria, with an alternate set of thresholds.

[0141] In some example embodiments, the determination of the at least one selection criterion and / or the at least one threshold may be performed by the terminal device 110. For example, as for the time-based selection criterion (the first selection criterion), the terminal device 110 may determine the time threshold to be applied with the first selection criterion based on a cause for triggering SIB1 acquisition by the terminal device 110, a device battery status of the terminal device 110, and / or an overheating status of the terminal device 110. Alternatively, the determination of the at least one selection criterion and / or the at least one threshold may be performed by the network node 120.

[0142] The example embodiments of the present disclosure propose mechanisms for a scenario wherein a network node supports concurrently different SIB1 transmission modes including the periodic and OD-SIB1 transmission modes. Proposed mechanisms provide a balanced trade-off between network energy consumption and SIB1 acquisition latency.

[0143] On one hand, compared to the legacy approach of periodic SIB1 transmissions, the network may utilize a much longer SIB1 periodicity, e.g. 160 ms or longer, compared to the current 20-ms periodicity. This saves network energy at the cost of increased SIB1 acquisition latency. On the other hand, compared to OD-SIB1 transmissions, the solution herein may avoid the network having to respond to too many SIB1 requests, because there will be a criterion or criteria a terminal device has to fulfil in order to be allowed to perform the OD-SIB1 request.

[0144] Furthermore, the OD-SIB1 transmissions may not be beneficial when the number of OD-SIB1 requests is high because the signaling overhead of the OD-SIB1 procedure becomes too large and the network energy saving reduces. This means the network may be benefit from the OD-SIB1 transmission mode under a low-load scenario but may have to fall back to the legacy approach of periodic SIB1 transmissions when the load level increases. The combination of periodic and OD-SIB1 transmission modes may address this issue, by enabling the network to use an infrequent transmission periodicity (e.g. 160 ms) and at the same time handle terminal devices with stricter latency requirements by conditionally allowing OD-SIB1. Therefore, this solution may increase the applicability to a wider range of load scenarios.

[0145] FIG. 7 illustrates a more specific example of a signaling flow 700 of selection of SIB1 transmission mode in accordance with some example embodiments of the present disclosure. The signaling flow 700 involves a network node 120 and one or more terminal devices 110. The signaling flow 700 will be described from the perspective of one terminal device, the i-th terminal device 110.

[0146] In the signaling flow 700, the network node 120 transmits (705) an indication (MIB or other indication information) to indicate concurrent support of periodic SIB1 and on-demand SIB1 transmission modes. The terminal device 110 receives (710) such an indication.

[0147] The network node 120 transmits (715) configuration information including at least one selection criterion for determining whether the terminal device can use one of the plurality of SIB1 transmission modes. Upon reception (720) of the configuration information, the terminal device 110 may determine whether to use or wait for the periodic SIB1 according to the periodic SIB1 transmission mode, or whether to request for on- demand SIB1 based on the WUS configuration according to the on-demand SIB1 transmission mode.

[0148] At the side of the terminal device 110, the terminal device 110 detects (725) a trigger for SIB1 acquisition. The terminal device 110 may repeat the detecting of SIB1 acquisition if no trigger is detected. If the trigger for SIB1 acquisition is detected, the terminal device 110 may determine a need for SIB1 and thus the terminal device 110 applies (730) the configured selection criterion / criteria to select a SIB1 transmission mode, e.g., to determine if the terminal device 110 uses or wats for the periodic SIB1 or torequest for on-demand SIB1. As an alternative, instead of being configured by the network node, the selection criterion / criteria may be pre-configured to the terminal device 110.

[0149] If the terminal device 110 determines (735 A) to use or wait for the periodic SIB1, it may monitor for the next periodic SIB1 transmission. At the network side, the network node 120 transmits (720) SIB1 according to the periodic SIB1 transmission mode, using the configured periodicity. The terminal device 110 may receive and successfully decode SIB1 in the next SIB1 transmission.

[0150] If the terminal device 110 determines (735B) to request for on-demand SIB1, the terminal device 110 transmits (740) an on-demand SIB1 request to the network node 120. The network node 120 receives (745) the on-demand SIB1 request and may transmit (750) SIB1 to the terminal device 110. As such, the terminal device 110 receives (755) SIB1 according to the on-demand SIB1 transmission mode.

[0151] The example embodiments of the present disclosure provide a solution to maximize network energy savings by supporting the least frequent SIB1 transmission possible, e.g. by relying upon on demand SIB1 when and where appropriate, and supporting the minimum amount of on demand SIB1, e.g. by relying upon the next upcoming SIB1 when and where appropriate. The example embodiments of the present disclosure may provide for the network utilizing both of these mechanisms at the same time, where the terminal device may be configured to automatically select what combination of these two approaches to utilize based upon the particular UE scenario.

[0152] FIG. 8A shows a flowchart of an example method 800A implemented at a terminal device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 800A will be described from the perspective of the terminal device. In some example embodiments, the terminal device may be or may be comprised in the terminal device 110 in FIG. 1.

[0153] At block 810, the terminal device 110 receives, from a network node, an indication that the network node supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode. At block 820, the terminal device 110 selects either the first SIB1 transmission mode or the second transmissionmode for SIB1 acquisition. At block 830, the terminal device 110 initiates SIB1 acquisition according to the selected SIB1 transmission mode.

[0154] In some example embodiments, the selecting either the first SIB1 transmission mode or the second SIB1 transmission mode for SIB1 acquisition comprises: detecting a trigger for SIB1 acquisition; and based on detecting the trigger for SIB1 acquisition, selecting either the first SIB1 transmission mode or the second SIB1 transmission mode for SIB1 acquisition.

[0155] In some example embodiments, the indication that the network node supports the first SIB1 transmission mode and the second SIB1 transmission mode is received in a master information block. In some example embodiments, the method 800A comprises: receiving a wake-up signal configuration comprising the indication that the network node supports the first SIB1 transmission mode and the second SIB1 transmission mode. In some example embodiments, the method 800A further comprises: receiving wake-up signal configuration comprising a transmission repetition periodicity of the first SIB1 transmission mode.

[0156] In some example embodiments, the selecting either the first SIB1 transmission mode or the second SIB1 transmission mode for SIB1 acquisition is based on at least one selection criterion. In some example embodiments, the at least one selection criterion comprises at least one of: a first selection criterion based on at least one time threshold for a time duration until a next periodic SIB1 transmission, a second selection criterion based on a mobility status of the terminal device, a third selection criterion based on at least one radio threshold for a radio metric of the terminal device, a fourth selection criterion based on at least one latency threshold for a latency requirement of a service, a fifth selection criterion based on at least one quality of service threshold for a quality of service requirement of a service, a sixth selection criterion based on a service type, or a seventh selection criterion based on at least one device energy threshold for a device energy consumption of the terminal device.

[0157] In some example embodiments, the at least one selection criterion is configured by the network node or is pre-configured to the terminal device.

[0158] In some example embodiments, the method 800A further comprises: receiving, from the network node, a configuration comprising a configuration of the at least oneselection criterion and / or at least one threshold applied with the at least one selection criterion.

[0159] In some example embodiments, the method 800A further comprises: determining the at least one selection criterion and / or at least one threshold applied with the at least one selection criterion to be applicable for the selecting based on at least one of the following: a cause for triggering SIB1 acquisition by the terminal device; a device battery status of the terminal device; or an overheating status of the terminal device.

[0160] In some example embodiments, initiating SIB1 acquisition comprises: based on the selected SIB1 transmission mode being the first SIB1 transmission mode, monitoring for scheduling of periodic SIB1 from the network node; and monitoring for SIB1 according to the scheduling and a transmission repetition periodicity received via wakeup signal configuration. In some example embodiments, based on the selected SIB1 transmission mode being the second SIB1 transmission mode, transmitting an on-demand SIB1 request to request for SIB1 according to a received wake-up signal configuration.

[0161] In some example embodiments, a first apparatus capable of performing any of the method 800 (for example, the terminal device 110 in FIG. 1) may comprise means for performing the respective operations of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the terminal device 110 in FIG. 1. The first apparatus comprises means for receiving, from a network node, an indication that the network node supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; means for selecting either the first SIB1 transmission mode or the second transmission mode for SIB1 acquisition; and means for initiating SIB1 acquisition according to the selected SIB1 transmission mode. In some example embodiments, the first apparatus comprises other means for performing other actions or steps as described in the method 800A.

[0162] FIG. 8B shows a flowchart of an example method 800B implemented at a network node in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 800B will be described from the perspective of the network node 120 in FIG. 1.

[0163] At block 850, the network node 120 transmits, to a terminal device, an indication that the network node supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on- demand SIB1 transmission mode. At block 860, the network node 120 transmits SIB1 according to the first transmission mode. At block 870, based on a reception of an on- demand SIB1 request from the terminal device, the network node 120 transmits SIB1 to the terminal device according to the second SIB1 transmission mode.

[0164] In some example embodiments, the indication that the network node supports the first SIB1 transmission mode and the second SIB1 transmission mode is transmitted in a master information block. In some example embodiments, the method 800B comprises: transmitting, to the terminal device, a wake-up signal configuration comprising the indication that the network node supports the first SIB 1 transmission mode and the second SIB1 transmission mode. In some example embodiments, the method 800B comprises: transmitting, to the terminal device, a wake-up signal configuration comprising a transmission repetition periodicity of the first SIB1 transmission mode.

[0165] In some example embodiments, the method 800B comprises: transmitting, to the terminal device, a configuration comprising at least one of the following: at least one selection criterion, the at least one selection criterion being applicable by the terminal device for selecting either the first SIB1 transmission mode or the second transmission mode for SIB1 acquisition, or at least one threshold applied with the at least one selection criterion.

[0166] In some example embodiments, a second apparatus capable of performing any of the method 800B (for example, the network node 120 in FIG. 1) may comprise means for performing the respective operations of the method 800B. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the network node 120 in FIG. 1. In some example embodiments, the second apparatus comprises means for transmitting, to a terminal device, an indication that the second apparatus supports a first system information block 1, SIB1, transmission mode and a second SIB1 transmission mode, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1transmission mode; means for transmitting SIB1 according to the first transmission mode; and means for based on a reception of an on-demand SIB1 request from the terminal device, transmitting SIB1 to the terminal device according to the second SIB1 transmission mode. In some example embodiments, the first apparatus comprises other means for performing other actions or steps as described in the method 800B.

[0167] FIG. 9A shows a flowchart of an example method 900A implemented at a first apparatus in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 900A will be described from the perspective of the terminal device 110 in FIG. 1.

[0168] At block 910, the terminal device 110 receives, from a network node, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode. At block 920, the terminal device 110 selects, based on the at least one selection criterion, a SIB1 transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode. At block 930, the terminal device 110 initiates SIB1 acquisition according to the selected SIB1 transmission mode.

[0169] In some example embodiments, the method 900A further comprises: receiving, from the network node, a wake-up signal configuration comprising the configuration information indicating the at least one selection criterion for a SIB1 transmission mode.

[0170] In some example embodiments, the configuration further indicates that the network node supports the plurality of SIB1 transmission modes, and the method 900A further comprises: based on the configuration indicating that the network node supports the plurality of SIB1 transmission mode, selecting, based on the at least one selection criterion, a SIB1 transmission mode from the plurality of SIB1 transmission modes for SIB1 acquisition.

[0171] In some example embodiments, the at least one selection criterion comprises at least one of: a first selection criterion based on at least one time threshold for a time duration until a next periodic SIB1 transmission, a second selection criterion based on a mobility status of the first apparatus, a third selection criterion based on at least one radio threshold for a radio metric of the first apparatus, a fourth selection criterion based on atleast one latency threshold for a latency requirement of a service type, a fifth selection criterion based on at least one quality of service threshold for a quality of service requirement of a service type, a sixth selection criterion based on a service type, or a seventh selection criterion based on at least one device energy threshold for a device energy consumption of the first apparatus.

[0172] In some example embodiments, the method 900A further comprises: determining the at least one selection criterion and / or at least one threshold applied with the at least one selection criterion based on at least one of the following: a cause for triggering SIB1 acquisition by the first apparatus; a device battery status of the first apparatus; or an overheating status of the first apparatus.

[0173] In some example embodiments, the at least one selection criterion comprises the first selection criterion, and the selecting comprises: selecting the first SIB1 transmission mode based on the time duration until the next periodic SIB1 transmission being below a time threshold; or selecting the second SIB1 transmission based on the time duration until the next periodic SIB1 transmission exceeding the time threshold.

[0174] In some example embodiments, the at least one selection criterion comprises the second selection criterion, and the selecting comprises: selecting the first SIB1 transmission mode based on the mobility status of the first apparatus being a first mobility status; or selecting the second SIB1 transmission mode based on the mobility status of the first apparatus being a second mobility status with a higher mobility level than the first mobility status.

[0175] In some example embodiments, the at least one selection criterion comprises the third selection criterion, and the selecting comprises: selecting the first SIB1 transmission mode based on the radio metric of the first apparatus exceeding a radio threshold, selecting the second SIB1 transmission mode based on the radio metric of the first apparatus being below the radio threshold.

[0176] In some example embodiments, the at least one selection criterion comprises at least one of the fourth selection criterion and the fifth selection criterion, and the selecting comprises: selecting the first SIB1 transmission mode based on at least one of the following: the latency requirement of the service exceeding a latency threshold, or the quality of service requirement of the service exceeding a quality of service threshold; orselecting the second SIB1 transmission mode based on at least one of the following: the latency requirement of the service being below a latency threshold, or the quality of service requirement of the service being below a quality of service threshold.

[0177] In some example embodiments, the at least one selection criterion comprises the sixth selection criterion, and the service type is a delay-critical service; and the selecting comprises: selecting the first SIB1 transmission mode based on the first apparatus failing to support or be configured with the delay-critical service; or selecting the second SIB1 transmission mode based on the first apparatus supporting or being configured with the delay-critical service.

[0178] In some example embodiments, the at least one selection criterion comprises the seventh selection criterion, and the selecting comprises: selecting the first SIB1 transmission mode based on a device energy consumption of the first apparatus exceeding a device energy threshold; or selecting the second SIB1 transmission mode based on a device energy consumption of the first apparatus being below the device energy threshold.

[0179] In some example embodiments, the initiating SIB1 acquisition comprises: based on the selected SIB1 transmission mode being the periodic SIB1 transmission mode, monitoring for scheduling of periodic SIB1 from the network node; or based on the selected SIB1 transmission mode being the on-demand SIB1 transmission mode, transmitting an on-demand SIB1 request to request for SIB1.

[0180] In some example embodiments, a first apparatus capable of performing any of the method 900A (for example, the terminal device 110 in FIG. 1) may comprise means for performing the respective operations of the method 900A. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The first apparatus may be implemented as or included in the terminal device 110 in FIG. 1. In some example embodiments, the first apparatus comprises means for receiving, from a network node, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode; means for selecting, based on the at least one selection criterion, a SIB1 transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode; and means for initiating SIB1 acquisition according to the selected SIB1 transmission mode. In some example embodiments, the first apparatus comprisesother means for performing other actions or steps as described in the method 900A.

[0181] FIG. 9B shows a flowchart of an example method 900B implemented at a network node in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 900B will be described from the perspective of the network node 120 in FIG. 1.

[0182] At block 950, the network node 120 transmits, to a terminal device, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode. At block 960, the network node 120 transmits SIB1 according to the periodic transmission mode. At block 970, based on a reception of an on-demand SIB1 request from the terminal device, the network node 120 transmits SIB1 to the terminal device according to the on-demand SIBltransmission mode.

[0183] In some example embodiments, the method 900B further comprises: transmitting, to the terminal device, a wake-up signal configuration comprising the configuration indicating the at least one selection criterion for a SIB1 transmission mode. In some example embodiments, the configuration further indicates that the second apparatus supports the plurality of SIB1 transmission modes.

[0184] In some example embodiments, the at least one selection criterion comprises at least one of a first selection criterion based on at least one time threshold for a time duration until a next periodic SIB1 transmission, a second selection criterion based on a mobility status of the terminal device, a third selection criterion based on at least one radio threshold for a radio metric of the terminal device, a fourth selection criterion based on at least one latency threshold for a latency requirement of a service type, a fifth selection criterion based on at least one quality of service threshold for a quality of service requirement of a service type, a sixth selection criterion based on a service type, or a seventh selection criterion based on at least one device energy threshold for a device energy consumption of the terminal device.

[0185] In some example embodiments, a second apparatus capable of performing any of the method 900B (for example, the network node 120 in FIG. 1) may comprise means forperforming the respective operations of the method 900B. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module. The second apparatus may be implemented as or included in the network node 120 in FIG. 1. In some example embodiments, the second apparatus comprises means for transmitting, to a terminal device, a configuration indicating at least one selection criterion for a system information block 1, SIB1, transmission mode from a plurality of SIB1 transmission modes for SIB1 acquisition, wherein the plurality of SIB1 transmission modes comprise at least a periodic SIB1 transmission mode and an on-demand SIB1 transmission mode means for transmitting SIB1 according to the periodic transmission mode; and means for based on a reception of an on-demand SIB1 request from the terminal device, transmitting SIB1 to the terminal device according to the on-demand SIB transmission mode. In some example embodiments, the second apparatus comprises other means for performing other actions or steps as described in the method 900B.

[0186] FIG. 10 shows a flowchart of an example method 1000 implemented at a terminal device in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the method 1000 will be described from the perspective of the terminal device 110 in FIG. 1.

[0187] At block 1010, based on detecting a trigger for system information block 1, SIBling acquisition, the terminal device 110 determines a time duration until a next periodic SIB1 transmission. At block 1020, the terminal device 110 selects either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode. At block 1030, the terminal device 110 initiates SIB1 acquisition with a network node according to the selected SIB1 transmission mode.

[0188] In some example embodiments, the method 1000 further comprises: receiving, from the network node, a configuration indicating at least one of thing time threshold to be applied in selecting either the first SIB1 transmission mode or the second SIB1 transmission mode; or a time-based selection criterion to be applied in selecting either the first SIB1 transmission mode or the second SIB1 transmission mode, wherein the timebased selection criterion is based on the time threshold for the time duration until the next periodic SIB1 transmission. In some example embodiments, the method 1000 furthercomprises: receiving, from the network node, an indication that the network node supports the first SIB1 transmission mode and the second SIB1 transmission mode.

[0189] In some example embodiments, the method 1000 further comprises: determining the time threshold based on at least one of the following: a cause for triggering SIB1 acquisition by the first apparatus; a device battery status of the first apparatus; or an overheating status of the first apparatus.

[0190] In some example embodiments, the method 1000 further comprises: selecting the first SIB1 transmission mode based on the time duration until the next periodic SIB1 transmission being below a time threshold; or selecting the second SIB1 transmission based on the time duration until the next periodic SIB1 transmission exceeding the time threshold. In some example embodiments, the method 1000 further comprises: selecting either the first SIB1 transmission mode or the second SIB1 transmission mode further based on a mobility status of the first apparatus.

[0191] In some example embodiments, the method 1000 further comprises: selecting the first SIB1 transmission mode based on the mobility status of the first apparatus being a first mobility status and the time duration until the next periodic SIB1 transmission being below a time threshold; or selecting the second SIB1 transmission mode based on the mobility status of the first apparatus being a second mobility status, or the time duration until the next periodic SIB1 transmission exceeding the time threshold, wherein the second mobility status has a higher mobility level than the first mobility status. In some example embodiments, the first mobility status is a low mobility status or a stationary status, and the second mobility status is a high mobility status or a medium mobility status.

[0192] In some example embodiments, the method 1000 further comprises: based on the selected SIB1 transmission mode being the periodic SIB1 transmission mode, monitoring for scheduling of periodic SIB1 from the network node; and based on the selected SIB1 transmission mode being the on-demand SIB1 transmission mode, transmitting an on-demand SIB1 request to request for SIB1.

[0193] In some example embodiments, a first apparatus capable of performing any of the method 1000 (for example, the terminal device 110 in FIG. 1) may comprise means for performing the respective operations of the method 1000. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry orsoftware module. The first apparatus may be implemented as or included in the terminal device 110 in FIG. 1. In some example embodiments, the first apparatus comprises means for based on detecting a trigger for system information block 1, SIBling acquisition, determine a time duration until a next periodic SIB1 transmission; means for selecting either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; and means for initiating SIB1 acquisition with a network node according to the selected SIB1 transmission mode. In some example embodiments, the second apparatus comprises other means for performing other actions or steps as described in the method 1000.

[0194] FIG. 11 is a simplified block diagram of a device 1100 that is suitable for implementing example embodiments of the present disclosure. The device 1100 may be provided to implement a communication device, for example, the terminal device 110 or the network node 120 as shown in FIG. 1. As shown, the device 1100 includes one or more processors 1111, one or more memories 1120 coupled to the processor 1110, and one or more communication modules 1140 coupled to the processor 1110.

[0195] The communication module 1140 is for bidirectional communications. The communication module 1140 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interfaces may represent any interface that is necessary for communication with other network elements. In some example embodiments, the communication module 1140 may include at least one antenna.

[0196] The processor l l lOmay be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1100 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0197] The memory 1120 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1124, an electrically programmable read onlymemory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), an optical disk, a laser disk, and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random-access memory (RAM) 1122 and other volatile memories that will not last in the power-down duration.

[0198] A computer program 1130 includes computer executable instructions that are executed by the associated processor 1110. The instructions of the program 1130 may include instructions for performing operations / acts of some example embodiments of the present disclosure. The program 1130 may be stored in the memory, e.g., the ROM 1124. The processor 1110 may perform any suitable actions and processing by loading the program 1130 into the RAM 1122.

[0199] The example embodiments of the present disclosure may be implemented by means of the program 1130 so that the device 1100 may perform any process of the disclosure as discussed with reference to FIG. 3 to FIG. 10. The example embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0200] In some example embodiments, the program 1130 may be tangibly contained in a computer readable medium which may be included in the device 1100 (such as in the memory 1120) or other storage devices that are accessible by the device 1100. The device 1100 may load the program 1130 from the computer readable medium to the RAM 1122 for execution. In some example embodiments, the computer readable medium may include any types of non-transitory storage medium, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0201] FIG. 12 shows an example of the computer readable medium 1110 which may be in form of CD, DVD or other optical storage disk. The computer readable medium 1110 has the program 1130 stored thereon.

[0202] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, and other aspects may be implemented infirmware or software which may be executed by a controller, microprocessor or other computing device. Although various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method 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.

[0203] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer readable medium, such as a non- transitory computer readable medium. The computer program product includes computerexecutable instructions, such as those included in program modules, being executed in a device on a target physical or virtual processor, to carry out any of the methods as described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0204] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0205] In the context of the present disclosure, the computer program code or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0206] The computer readable medium may be a computer readable signal medium ora computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0207] Further, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, although several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless explicitly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated, various features that are described in the context of a single embodiment may also be implemented in a plurality of embodiments separately or in any suitable sub-combination.

[0208] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:

1. A first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: based on detecting a trigger for system information block 1, SIB1, acquisition, determine a time duration until a next periodic SIB1 transmission; select either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; and initiate SIB1 acquisition with a network node according to the selected SIB1 transmission mode.

2. The first apparatus of claim 1, wherein the first apparatus is caused to: receive, from the network node, a configuration indicating at least one of: the time threshold to be applied in selecting either the first SIB1 transmission mode or the second SIB1 transmission mode; or a time-based selection criterion to be applied in selecting either the first SIB1 transmission mode or the second SIB1 transmission mode, wherein the time-based selection criterion is based on the time threshold for the time duration until the next periodic SIB1 transmission.

3. The first apparatus of claim 1 or 2, wherein the first apparatus is caused to: receive, from the network node, an indication that the network node supports the firstSIB1 transmission mode and the second SIB1 transmission mode.

4. The first apparatus of any of claims 1 to 3, wherein the first apparatus is further caused to: determine the time threshold based on at least one of the following: a cause for triggering SIB1 acquisition by the first apparatus; a device battery status of the first apparatus; or an overheating status of the first apparatus.

455. The first apparatus of any of claims 1 to 4, wherein the first apparatus is caused to: select the first SIB 1 transmission mode based on the time duration until the next periodic SIB1 transmission being below a time threshold; or select the second SIB1 transmission based on the time duration until the next periodic SIB 1 transmission exceeding the time threshold.

6. The first apparatus of any of claims 1 to 5, wherein the first apparatus is caused to: select either the first SIB1 transmission mode or the second SIB1 transmission mode further based on a mobility status of the first apparatus.

7. The first apparatus of claim 6, wherein the first apparatus is caused to: select the first SIB 1 transmission mode based on the mobility status of the first apparatus being a first mobility status and the time duration until the next periodic SIB1 transmission being below a time threshold; or select the second SIB1 transmission mode based on the mobility status of the first apparatus being a second mobility status, or the time duration until the next periodic SIB1 transmission exceeding the time threshold, wherein the second mobility status has a higher mobility level than the first mobility status.

8. The first apparatus of claim 7, wherein the first mobility status is a low mobility status or a stationary status, and the second mobility status is a high mobility status or a medium mobility status.

9. The first apparatus of any of the claims 1 to 8, wherein the first apparatus is caused to: based on the selected SIB1 transmission mode being the periodic SIB1 transmission mode, monitor for scheduling of periodic SIB 1 from the network node; and monitor for SIB1 according to the scheduling and a transmission repetition periodicity received via wake-up signal configuration.

10. The first apparatus of any of the claims 1 to 8, wherein the first apparatus is caused to:46based on the selected SIB1 transmission mode being the on-demand SIB1 transmission mode, transmit an on-demand SIB1 request to request for SIB1 according to a received wakeup signal configuration.

11. A method comprising: based on detecting a trigger for system information block 1, SIB1, acquisition, determining, by a terminal device, a time duration until a next periodic SIB1 transmission; selecting either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; and initiating SIB1 acquisition according to the selected SIB1 transmission mode.

12. The method of claim 11, further comprising: receiving, from the network node, configuration indicating at least one of: the time threshold to be applied in selecting either the first SIB1 transmission mode or the second SIB1 transmission mode; or a time-based selection criterion to be applied in selecting either the first SIB1 transmission mode or the second SIB1 transmission mode, wherein the time-based selection criterion is based on the time threshold for the time duration until the next periodic SIB1 transmission.

13. The method of claim 11 or 12, further comprising: receiving, from the network node, an indication that the network node supports the first SIB1 transmission mode and the second SIB1 transmission mode.

14. The method of any of claims 11 to 13, further comprising: determining the time threshold based on at least one of the following: a cause for triggering SIB1 acquisition by the terminal device; a device battery status of the terminal device; or an overheating status of the terminal device.

15. The method of any of claims 11 to 14, wherein selecting either a first SIB147transmission mode or a second SIB1 transmission mode comprises: selecting the first SIB1 transmission mode based on the time duration until the next periodic SIB1 transmission being below a time threshold; or selecting the second SIB 1 transmission based on the time duration until the next periodic SIB 1 transmission exceeding the time threshold.

16. The method of any of claims 11 to 15, wherein selecting either a first SIB1 transmission mode or a second SIB1 transmission mode comprises: selecting either the first SIB1 transmission mode or the second SIB1 transmission mode further based on a mobility status of the terminal device.17 The method of claim 16, wherein selecting either the first SIB1 transmission mode or the second SIB1 transmission mode further based on a mobility status of the terminal device comprises: selecting the first SIB1 transmission mode based on the mobility status of the terminal device being a first mobility status and the time duration until the next periodic SIB1 transmission being below a time threshold; or selecting the second SIB1 transmission mode based on the mobility status of the terminal device being a second mobility status, or the time duration until the next periodic SIB1 transmission exceeding the time threshold, wherein the second mobility status has a higher mobility level than the first mobility status.

18. The method of any of the claims 11 to 17, wherein initiating SIB1 acquisition comprises: based on the selected SIB1 transmission mode being the periodic SIB1 transmission mode, monitoring for scheduling of periodic SIB1 from the network node; and monitoring for SIB1 according to the scheduling and a transmission repetition periodicity received via wake-up signal configuration, or based on the selected SIB1 transmission mode being the on-demand SIB1 transmission mode, transmitting an on-demand SIB1 request to request for SIB1 according to a received wake-up signal configuration.

19. A first apparatus, comprising: means for, based on detecting a trigger for system information block 1, SIB 1, acquisition, determining a time duration until a next periodic SIB1 transmission; means for selecting either a first SIB1 transmission mode or a second SIB1 transmission mode based on a comparison result between the time duration and a time threshold, wherein the first SIB1 transmission mode is a periodic SIB1 transmission mode and the second SIB1 transmission mode is an on-demand SIB1 transmission mode; and means for initiating SIB1 acquisition according to the selected SIB1 transmission mode.

20. A computer readable medium comprising instructions stored thereon for causing an apparatus at least to perform the method of any of claims 11 to 18.

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