Determining whether to include barred cell as candidate cell

Abstract

Disclosed is a method comprising determining a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, SIB1, from the first cell; determining, before the pre-defined time period expires, whether the first cell supports on-demand SIB1 transmission; and based on determining whether the first cell supports the on-demand SIB1 transmission, determine whether to include or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires.

Description

DETERMINING WHETHER TO INCLUDE BARRED CELL AS CANDIDATE CELLFIELD

[0001] The following example embodiments relate to wireless communication.BACKGROUND

[0002] If a cell is considered as barred due to failed acquisition of system information block type one (S1B1), the user equipment may exclude the barred cell as a candidate for cell selection or cell reselection for 300 seconds.SUMMARY

[0003] The scope of protection sought for various example embodiments is set out by the claims. The example embodiments and features, if any, described in this specification that do not fall under the scope of the claims are to be interpreted as examples useful for understanding various embodiments.

[0004] According to a first aspect, there is provided an apparatus comprising: means for determining a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, S1B1, from the first cell; means for determining, before the pre-defined time period expires, whether the first cell supports on-demand S1B1 transmission; and means for determining whether to include or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires, based on determining whether the first cell supports the on-demand S1B1 transmission.

[0005] According to a second aspect, there is provided the apparatus of the first aspect, wherein the idle mode operation comprises at least one of: cell selection, cell reselection, public land mobile network selection, stand-alone nonpublic network selection, or location registration.

[0006] According to a third aspect, there is provided the apparatus of any of the first or second aspects, further comprising: means for receiving, from the first cell or from a second cell, an indication indicating that the first cell supports the on-demand SIB 1 transmission, wherein the means for determining whether thefirst cell supports the on-demand S1B1 transmission are configured to determine, based on the indication, that the first cell supports the on-demand S1B1 transmission, and wherein the means for determining whether to include or exclude the first cell as a candidate cell for the idle mode operation are configured to determine to include the first cell as a candidate cell for the idle mode operation before the pre-defined time period expires, based on determining that the first cell supports the on-demand S1B1 transmission.

[0007] According to a fourth aspect, there is provided the apparatus of the third aspect, wherein the determination to include the first cell as a candidate cell for the idle mode operation comprises determining to include the first cell as a candidate cell for cell selection or cell reselection before the pre-defined time period expires.

[0008] According to a fifth aspect, there is provided the apparatus of any of the first or second aspects, wherein the means for determining whether the first cell supports the on-demand S1B1 transmission are configured to determine that the first cell does not support the on-demand S1B1 transmission, if an indication indicating that the first cell supports the on-demand S1B1 transmission is not received from the first cell or from the second cell, and wherein the means for determining whether to include or exclude the first cell as a candidate cell for the idle mode operation are configured to determine to exclude the first cell as a candidate cell for the idle mode operation until the pre-defined time period expires, based on determining that the first cell does not support the on-demand S1B1 transmission.

[0009] According to a sixth aspect, there is provided the apparatus of the fifth aspect, wherein the determination to exclude the first cell as a candidate cell for the idle mode operation comprises determining to exclude the first cell as a candidate cell for cell selection or cell reselection until the pre-defined time period expires.

[0010] According to a seventh aspect, there is provided the apparatus of any of the third to sixth aspects, wherein the indication comprises a wake-upsignal configuration associated with a wake-up signal for requesting the on- demand S1B1 transmission of the first cell.

[0011] According to an eighth aspect, there is provided the apparatus of the seventh aspect, further comprising means for switching from the first cell to the second cell for attempting to receive the wake-up signal configuration from the second cell before the pre-defined time period expires.

[0012] According to a ninth aspect, there is provided the apparatus of any of the seventh or eighth aspects, further comprising: means for transmitting, to the first cell or to the second cell, the wake-up signal for requesting the on- demand S1B1 transmission of the first cell, based on determining to include the first cell as a candidate cell for the idle mode operation before the pre-defined time period expires; and means for receiving the on-demand S1B1 transmission of the first cell from the first cell or from the second cell.

[0013] According to a tenth aspect, there is provided the apparatus of any of the third to sixth aspects, wherein the indication is comprised in a master information block of the first cell.

[0014] According to an eleventh aspect, there is provided the apparatus of any of the third to sixth aspects, wherein the indication is comprised in downlink control information of the first cell.

[0015] According to a twelfth aspect, there is provided the apparatus of any of the third to sixth aspects, wherein the indication is comprised in downlink control information of the second cell.

[0016] According to a thirteenth aspect, there is provided the apparatus of any of the first to twelfth aspects, wherein the apparatus is a user equipment.

[0017] According to a fifteenth aspect, there is provided a method comprising: determining a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, S1B1, from the first cell; determining, before the pre-defined time period expires, whether the first cell supports on-demand S1B1 transmission; and based on determining whether the first cell supports the on-demand S1B1 transmission, determine whether toinclude or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires.

[0018] According to a sixteenth aspect, there is provided a computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: determining a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, S1B1, from the first cell; determining, before the predefined time period expires, whether the first cell supports on-demand S1B1 transmission; and based on determining whether the first cell supports the on- demand S1B1 transmission, determine whether to include or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires.

[0019] According to a seventeenth aspect, there is provided a non- transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: determining a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, S1B1, from the first cell; determining, before the pre-defined time period expires, whether the first cell supports on-demand S1B1 transmission; and based on determining whether the first cell supports the on-demand S1B1 transmission, determine whether to include or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires.

[0020] According to an eighteenth aspect, there is provided a computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: determining a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, S1B1, from the first cell; determining, before the pre-defined time period expires, whether the first cell supports on- demand S1B1 transmission; and based on determining whether the first cell supports the on-demand S1B1 transmission, determine whether to include orexclude the first cell as a candidate cell for an idle mode operation before the predefined time period expires.

[0021] According to a nineteenth aspect, there is provided an apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: determine a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, S1B1, from the first cell; determine, before the pre-defined time period expires, whether the first cell supports on-demand S1B1 transmission; and based on determining whether the first cell supports the on-demand S1B1 transmission, determine whether to include or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the following, various example embodiments will be described in greater detail with reference to the accompanying drawings, in which FIG. 1A illustrates an example of a wireless communication network; FIG. IB illustrates an example of a system;FIG. 2 illustrates a signal flow diagram;FIG. 3 illustrates a signal flow diagram;FIG. 4 illustrates a signal flow diagram;FIG. 5 illustrates a flow chart; andFIG. 6 illustrates an example of an apparatus.DETAILED DESCRIPTION

[0023] The following embodiments are exemplifying. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments within the scope of the claims. Furthermore, the words "comprising" and "including" should be understood as not limiting the described embodimentsto consist of only those features that have been mentioned, and such embodiments may also contain features that have not been specifically mentioned. Reference numbers, in the description and / or in the claims, serve to illustrate the embodiments with reference to the drawings, without limiting the embodiments to these examples only.

[0024] Some example embodiments described herein may be implemented in a wireless communication network comprising a radio access network based on one or more of the following radio access technologies (RATs): global system for mobile communications (GSM) or any other second generation (2G) radio access technology, universal mobile telecommunication system (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), long term evolution (LTE), LTE -Advanced, fourth generation (4G), fifth generation (5G), 5G new radio (NR), 5G-Advanced (i.e., 3GPP NR Rel-18 and beyond), or sixth generation (6G). Some examples of radio access networks include the universal mobile telecommunications system (UMTS) radio access network (UTRAN), the evolved universal terrestrial radio access network (E- UTRA), or the next generation radio access network (NG-RAN). The wireless communication network may further comprise a core network, and some example embodiments may also be applied to network functions of the core network.

[0025] It should be noted that the embodiments are not restricted to the wireless communication network given as an example, but a person skilled in the art may also apply the solution to other wireless communication networks or systems provided with necessary properties. For example, some example embodiments may also be applied to a communication system based on IEEE 802.11 specifications, or a communication system based on IEEE 802.15 specifications. IEEE is an abbreviation for the Institute of Electrical and Electronics Engineers.

[0026] FIG. 1A depicts an example of a simplified wireless communication network showing some physical and logical entities. The connections shown in FIG. 1A may be physical connections or logical connections. It is apparent to a person skilled in the art that the wireless communicationnetwork may also comprise other physical and logical entities than those shown inFIG. 1A.

[0027] The example embodiments described herein are not, however, restricted to the wireless communication network given as an example but a person skilled in the art may apply the example embodiments described herein to other wireless communication networks provided with necessary properties.

[0028] The example wireless communication network shown in FIG. 1A includes a radio access network (RAN) and a core network 110.

[0029] FIG. 1A shows user equipment (UE) 100, 102 configured to be in a wireless connection on one or more communication channels in a radio cell with an access node 104 of a radio access network.

[0030] The access node 104 may comprise a computing device configured to control the radio resources of the access node 104 and to be in a wireless connection with one or more UEs 100, 102. The access node 104 may also be referred to as a base station, a base transceiver station (BTS), an access point, a cell site, a network node, a radio access network node, or a RAN node.

[0031] The access node 104 may be, for example, an evolved NodeB (abbreviated as eNB or eNodeB), or a next generation evolved NodeB (abbreviated as ng-eNB), or a next generation NodeB (abbreviated as gNB or gNodeB), providing the radio cell. The access node 104 may include or be coupled to transceivers. From the transceivers of the access node 104, a connection may be provided to an antenna unit that establishes a bi-directional radio link to one or more UEs 100, 102. The antenna unit may comprise an antenna or antenna element, or a plurality of antennas or antenna elements.

[0032] The wireless connection (e.g., radio link) from a UE 100, 102 to the access node 104 may be called uplink (UL) or reverse link, and the wireless connection (e.g., radio link) from the access node 104 to the UE 100, 102 may be called downlink (DL) or forward link. A UE 100 may also communicate directly with another UE 102, and vice versa, via a wireless connection generally referred to as a sidelink (SL). It should be appreciated that the access node 104 or itsfunctionalities may be implemented by using any node, host, server, access point or other entity suitable for providing such functionalities.

[0033] The radio access network may comprise more than one access node 104, in which case the access nodes may also be configured to communicate with one another over wired or wireless links. These links between access nodes may be used for sending and receiving control plane signaling and also for routing data from one access node to another access node.

[0034] The access node 104 may further be connected to a core network (CN) 110. The core network 110 may comprise an evolved packet core (EPC) network and / or a 5thgeneration core network (5GC). The EPC may comprise network entities, such as a serving gateway (S-GW for routing and forwarding data packets), a packet data network gateway (P-GW) for providing connectivity of UEs to external packet data networks, and / or a mobility management entity (MME). The 5GC may comprise one or more network functions, such as at least one of: a user plane function (UPF), an access and mobility management function (AMF), a location management function (LMF), and / or a session management function (SMF).

[0035] The core network 110 may also be able to communicate with one or more external networks 113, such as a public switched telephone network or the Internet, or utilize services provided by them. For example, in 5G wireless communication networks, the UPF of the core network 110 may be configured to communicate with an external data network via an N6 interface. In LTE wireless communication networks, the P-GW of the core network 110 may be configured to communicate with an external data network.

[0036] It should also be understood that the distribution of functions between core network operations and access node operations may differ in future wireless communication networks compared to that of the LTE or 5G, or even be non-existent.

[0037] The illustrated UE 100, 102 is one type of an apparatus to which resources on the air interface may be allocated and assigned. The UE 100, 102 may also be called a wireless communication device, a subscriber unit, a mobile station,a remote terminal, an access terminal, a user terminal, a terminal device, or a user device, just to mention but a few names. The UE 100, 102 may be a computing device operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of computing devices: a mobile phone, a smartphone, a personal digital assistant (PDA), a handset, a computing device comprising a wireless modem (e.g., an alarm or measurement device, etc.), a laptop computer, a desktop computer, a tablet, a game console, a notebook, a multimedia device, a reduced capability (RedCap) device, a wearable device (e.g., a watch, earphones or eyeglasses) with radio parts, a sensor comprising a wireless modem, or a computing device comprising a wireless modem integrated in a vehicle.

[0038] It should be appreciated that the UE 100, 102 may also be a nearly exclusive uplink-only device, of which an example may be a camera or video camera loading images or video clips to a network. The UE 100, 102 may also be a device having capability to operate in an Internet of Things (loT) network, which is a scenario in which objects may be provided with the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction.

[0039] The wireless communication network may also be able to support the usage of cloud services. For example, at least part of core network operations may be carried out as a cloud service (this is depicted in FIG. 1A by “cloud” 114). The UE 100, 102 may also utilize the cloud 114. In some applications, the computation for a given UE may be carried out in the cloud 114 or in another UE.

[0040] The wireless communication network may also comprise a central control entity, such as a network management system (NMS), or the like. The NMS is a centralized suite of software and hardware used to monitor, control, and administer the network infrastructure. The NMS is responsible for a wide range of tasks such as fault management, configuration management, security management, performance management, and accounting management. The NMS enables network operators to efficiently manage and optimize network resources, ensuring that the network delivers high performance, reliability, and security.

[0041] 5G enables using multiple-input and multiple-output (M1M0) antennas in the access node 104 and / or the UE 100, 102, many more base stations or access nodes than an LTE network (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and employing a variety of radio technologies depending on service needs, use cases and / or spectrum available. 5G wireless communication networks may support a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine-type applications, such as (massive) machine-type communications (mMTC), including vehicular safety, different sensors and real-time control.

[0042] In 5G wireless communication networks, access nodes and / or UEs may have multiple radio interfaces, such as below 6 gigahertz (GHz), centimeter wave (cmWave) and millimeter wave (mmWave), and also being integrable with legacy radio access technologies, such as LTE. Integration with LTE may be implemented, for example, as a system, where macro coverage may be provided by LTE, and 5G radio interface access may come from small cells by aggregation to LTE. In other words, a 5G wireless communication network may support both inter-RAT operability (such as interoperability between LTE and 5G) and inter-Rl operability (inter-radio interface operability, such as between below 6GHz, cmWave, and mmWave).

[0043] 5G wireless communication networks may also apply network slicing, in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the same physical infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

[0044] In one embodiment, an access node 104 may comprise: a radio unit (RU) 103 comprising a radio transceiver (TRX), i.e., a transmitter (Tx) and a receiver (Rx); one or more distributed units (DUs) 105 that may be used for the so- called Layer 1 (LI) processing and real-time Layer 2 (L2) processing; and a central unit (CU) 108 (also known as a centralized unit) that may be used for non-real-time L2 and Layer 3 (L3) processing. The CU 108 may be connected to the one or moreDUs 105 for example via an Fl interface. Such an embodiment of the access node 104 may enable the centralization of CUs relative to the cell sites and DUs, whereas DUs may be more distributed and may even remain at cell sites. The CU and DU together may also be referred to as baseband or a baseband unit (BBU). The CU and DU may also be comprised in a radio access point (RAP).

[0045] The CU 108 may be a logical node hosting radio resource control (RRC), service data adaptation protocol (SDAP) and / or packet data convergence protocol (PDCP), of the NR protocol stack for an access node 104. The CU 108 may comprise a control plane (CU-CP), which may be a logical node hosting the RRC and the control plane part of the PDCP protocol of the NR protocol stack for the access node 104. The CU 108 may further comprise a user plane (CU-UP), which may be a logical node hosting the user plane part of the PDCP protocol and the SDAP protocol of the CU for the access node 104.

[0046] The DU 105 may be a logical node hosting radio link control (RLC), medium access control (MAC) and / or physical (PHY) layers of the NR protocol stack for the access node 104. The operations of the DU 105 may be at least partly controlled by the CU 108. It should also be understood that the distribution of functions between the DU 105 and the CU 108 may vary depending on the implementation.

[0047] Cloud computing systems may also be used to provide the CU 108 and / or DU 105. A CU provided by a cloud computing system may be referred to as a virtualized CU (vCU). In addition to the vCU, there may also be a virtualized DU (vDU) provided by a cloud computing system. Furthermore, there may also be a combination, where the DU may be implemented on so-called bare metal solutions, for example application-specific integrated circuit (ASIC) or customerspecific standard product (CSSP) system-on-a-chip (SoC).

[0048] Edge cloud may be brought into the radio access network by utilizing network function virtualization (NFV) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a computing system operationally coupled to a remote radio head (RRH) or a radio unit (RU) 103 of an access node 104. It is also possible that accessnode operations may be performed on a distributed computing system or a cloud computing system located at the access node 104. Application of cloud RAN architecture enables RAN real-time functions being carried out at the radio access network (e.g., in a DU 105), and non-real-time functions being carried out in a centralized manner (e.g., in a CU 108).

[0049] 5G (or new radio, NR) wireless communication networks may support multiple hierarchies, where multi-access edge computing (MEC) servers may be placed between the core network 110 and the access node 104. It should be appreciated that MEC may be applied in LTE wireless communication networks as well.

[0050] A 5G wireless communication network (“5G network”) may also comprise a non-terrestrial communication network, such as a satellite communication network, to enhance or complement the coverage of the 5G radio access network. For example, satellite communication may support the transfer of data between the 5G radio access network and the core network 110, enabling more extensive network coverage. Possible use cases may include: providing service continuity for machine-to-machine (M2M) or Internet of Things (loT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, and future railway, maritime, or aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (i.e., systems in which hundreds of (nano)satellites are deployed). A given satellite 106 in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on-ground cells may be created through an on-ground relay access node or by an access node located on-ground or in a satellite.

[0051] It is obvious for a person skilled in the art that the access node 104 depicted in FIG. 1A is just an example of a part of a radio access network, and in practice the radio access network may comprise a plurality of access nodes 104, the UEs 100, 102 may have access to a plurality of radio cells, and the radio access network may also comprise other apparatuses, such as physical layer relay accessnodes or other entities. At least one of the access nodes may be a Home eNodeB or a Home gNodeB. A Home gNodeB or a Home eNodeB is a type of access node that may be used to provide indoor coverage inside a home, office, or other indoor environment.

[0052] Additionally, in a geographical area of a radio access network, a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which may be large cells having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The access node(s) 104 of FIG. 1A may provide any kind of these cells. A cellular radio network may be implemented as a multilayer access networks including several kinds of radio cells. In multilayer access networks, one access node may provide one kind of a radio cell or radio cells, and thus a plurality of access nodes may be needed to provide such a multilayer access network.

[0053] For fulfilling the need for improving performance of radio access networks, the concept of “plug-and-play” access nodes may be introduced. A radio access network, which may be able to use “plug-and-play” access nodes, may include, in addition to Home eNodeBs or Home gNodeBs, a Home Node B gateway (HNB-GW) (not shown in FIG. 1A). An HNB-GW, which may be installed within an operator’s radio access network, may aggregate traffic from a large number of Home eNodeBs or Home gNodeBs back to a core network 110 of the operator.

[0054] 6G wireless communication networks are expected to adopt flexible decentralized and / or distributed computing systems and architecture and ubiquitous computing, with local spectrum licensing, spectrum sharing, infrastructure sharing, and intelligent automated management underpinned by mobile edge computing, artificial intelligence, short-packet communication and blockchain technologies. Key features of 6G may include intelligent connected management and control functions, programmability, integrated sensing and communication, reduction of energy footprint, trustworthy infrastructure, scalability and affordability. In addition to these, 6G is also targeting new use casescovering the integration of localization and sensing capabilities into system definition to unifying user experience across physical and digital worlds.

[0055] Given that networks are dimensioned for peak load, and that the number of hours that cells are at peak load may be relatively low, there is a large amount of time where the cells are at low or medium loads. These periods of times, when the cell load is low, are an opportunity for network energy savings (NES). Some techniques for enabling network energy savings may include, for example, on-demand synchronization signal block (SSB), SSB-less cells, and on-demand system information block type 1 (S1B1).

[0056] An SSB-less cell means that the cell may transition to a mode where it stops broadcasting the SSB based on a predetermined condition being met. This can contribute to reducing the energy consumption of the network, and therefore make the network more sustainable.

[0057] On-demand SSB means that the access node 104 may stop the periodic legacy transmissions of the SSB of the cell, but a UE 100, 102 may request the access node 104 to transmit the SSB of the cell when it is needed.

[0058] On-demand S1B1 (OD-S1B1) means that the access node 104 may stop the periodic legacy transmissions of S1B1 of the cell, but a UE 100, 102 may request the access node 104 to transmit the S1B1 of the cell when it is needed by transmitting an uplink wake-up signal (WUS) from the UE 100, 102 to the access node 104.

[0059] FIG. IB illustrates an example of a wireless communication system. FIG. IB may be understood to depict a part of the wireless communication network of FIG. 1A, but with greater accuracy with respect to an OD-S1B1 scenario. The system of FIG. IB comprises a NES cell 121 controlled by a first access node 104, a cell A 122 controlled by a second access node 104B, and a UE 100 in an idle (RRCJDLE) mode or inactive (RRCJNACT1VE) mode. Alternatively, the NES cell 121 and the cell A 122 may be controlled by the same access node (e.g., access node 104).

[0060] The NES cell 121 refers to a cell that may transmit an on- demand S1B1 transmission in response to an uplink wake-up signal transmittedfrom a UE 100. The NES cell 121 may support switching between on-demand S1B1 and legacy S1B1 operations (i.e., the periodic S1B1 transmission of the legacy procedure can be deactivated or activated as needed). The NES cell 121 may also be referred to as a non-anchor cell or a first cell herein.

[0061] The cell A 122 refers to a cell that is periodically transmitting at least its own S1B1 according to a legacy procedure (e.g., up to NR Release 18). The UE 100 is able to detect the cell A 122 and camp on it. The cell A 122 may also be referred to as an anchor cell or a second cell herein.

[0062] The UE 100 may transmit the uplink wake-up signal to the NES cell 121 or to the cell A 122 for requesting the on-demand S1B1 transmission of the NES cell 121. The UE 100 may obtain the wake-up signal configuration associated with the uplink wake-up signal from the NES cell 121 or from the cell A 122.

[0063] For example, the UE 100 may camp on the NES cell 121 and obtain the wake-up signal configuration from the cell A 122 (or from the access node 104B controlling the cell A 122). In this case, the UE 100 may need to switch from the NES cell 121 to the cell A 122 to obtain the wake-up signal configuration. However, before switching to the cell A 122, the UE 100 is not able to receive any S1B1 from the NES cell 121, since the on-demand S1B1 is transmitted based on an uplink wake-up signal request from the UE 100. As the UE 100 is camping on the NES cell 121, the UE 100 has not yet received the wake-up signal configuration from the cell A 122. Therefore, for a UE 100 camping on a NES cell 121, there is a challenge in how the UE 100 can identify that the NES cell 121 is an on-demand S1B1 cell. Without this identification, the UE 100 may bar the NES cell 121 due to no reception of S1B1 (i.e., exclude the NES cell 121 as a candidate cell for cell selection or cell reselection for up to 300 seconds).

[0064] Some options for the UE 100 to identify a NES cell (i.e., to identify that the cell is operating in OD-S1B1 transmission mode) may include: by the wake-up signal configuration, by the master information block (M1B) of the NES cell 121, by downlink control information (DC1) from the NES cell 121 (e.g., DC1 l_0), or by UE blind detection, or any combination of these.

[0065] For example, for identifying the NES cell 121 based on the wakeup signal configuration, the UE 100 (which is camping on the NES cell 121) may need to select or reselect the cell A 122 to receive the wake-up signal configuration for requesting the OD-S1B1 of the NES cell 121, and thus identify that the previous cell 121 was a NES cell. However, the UE 100 may treat the NES cell 121 as if the cell status is “barred” due to being unable to acquire the legacy S1B1 from the NES cell 121, which means that the UE 100 may exclude the barred cell 121 as a candidate cell for cell selection or cell reselection for up to 300 seconds (5 minutes). Herein a barred cell refers to a cell that the UE 100 is notallowed to camp on, and an unbarred (not barred) cell refers to a cell that the UE 100 is allowed to camp on. Barring the cell 121 for up to 300 seconds may be excessive and impractical, if the cell 121 supports on-demand S1B1.

[0066] FIG. 2 illustrates a signal flow diagram depicting one of OD-S1B1 scenarios.

[0067] Referring to FIG. 2, at 201, the first cell 121 (or the NES cell, the first access node 104) and the second cell 122 (or the Cell A, the second access node 104B) may exchange information via backhaul signaling. For example, the first cell 121 (or the first access node 104) may provide a wake-up signal configuration to the second cell 122 (or the second access node 104B) for the uplink wake-up signal to be used for requesting the OD-S1B1 transmission of the first cell 121. The wakeup signal configuration may indicate, for example, the radio resources to be used for transmitting the wake-up signal.

[0068] Alternatively, the second cell 122 (or the second access node 104B) may generate the wake-up signal configuration for the uplink wake-up signal to be used for requesting the OD-S1B1 transmission of the first cell 121.

[0069] At 202, the UE 100 selects or reselects the first cell 121. The UE 100 monitors system information and possibly paging information from the first cell 121.

[0070] At 203, the UE 100 fails to acquire S1B1 from the first cell 121 after completing the cell selection or cell reselection to the first cell 121.

[0071] At 204, the UE 100 determines or considers the first cell 121 as barred for a pre-defined time period (e.g., 300 seconds) due to being unable to acquire the S1B1 from the first cell 121.

[0072] At 205, after barring the first cell (NES cell) 121, the UE 100 selects or reselects the second cell (cell A) 122. Upon completing the cell selection or cell reselection, the UE 100 is camping on the second cell 122 in idle (RRCJDLE) mode or in inactive (RRCJNACT1VE) mode. The UE 100 monitors the control channel of the second cell 122.

[0073] At 206, the UE 100 receives, from the second cell 122 (or from the second access node 104B), before the pre-defined time period (e.g., 300 seconds) expires, a wake-up signal configuration associated with a wake-up signal for requesting the OD-S1B1 transmission of the first cell 121. The wake-up signal configuration may be carried on, for example, S1B1 or other SIB (SIBx) or an RRC release message of the second cell 122. Alternatively, the wake-up signal configuration may be received from the first cell 121, for example in an RRC release message. Alternatively, the wake-up signal configuration may be pre-defined (e.g., hard-coded at the UE 100, or pre-defined in specifications), in which case the UE 100 may not need to receive the wake-up signal configuration from the second cell 122 or from the first cell 121, or the UE 100 may receive an indication or a pointer from the second cell 122 or from the first cell 121 to indicate which wake-up signal configuration to use from the pre-defined wake-up signal configurations.

[0074] The wake-up signal configuration may comprise an identifier, such as a physical cell identity (PCI) of the first cell 121. Herein the wake-up signal configuration is used as an example of an indication, which indicates that the first cell 121 supports OD-S1B1 transmission.

[0075] At 207, based on the wake-up signal configuration, the UE 100 determines that the first cell 121 supports OD-S1B1 transmission (i.e., that the first cell 121 is a NES cell) before the pre-defined time period (e.g., 300 seconds) expires. However, at this point, the UE 100 is unable to (re)selectthe first cell 121, since the pre-defined time period (e.g., 300 seconds) has not expired yet.

[0076] At 208, the UE 100 is able to select or reselect the first cell 121 eventually after the pre-defined time period (e.g., 300 seconds) has expired. In other words, the UE 100 has to wait for 300 seconds before being able to (re)select the first cell 121.

[0077] To solve the above problem, some example embodiments provide a method that allows the UE 100 to (re)select the barred cell based on determining that it supports on-demand S1B1, even if the pre-defined time period has not expired yet. In other words, in this case, the UE 100 may treat the barred cell as unbarred (not barred), and it does not have to wait for 300 seconds before being able to (re)select the barred cell. Thus, the UE 100 can (re)select the barred cell sooner, thus potentially providing better service quality and / or performance.

[0078] In one embodiment, after selecting or reselecting a cell from which a WUS configuration is received, the UE 100 may check from the “barred” cell list if any “barred” cell supports OD-S1B1 operation. Herein a barred cell refers to a cell that the UE 100 treats as if the cell status is barred, for example due to being unable to acquire S1B1 from the cell. If a barred cell supports OD-S1B1 operation, the UE 100 may revert the cell status to “not barred” (before the predefined time period expires), i.e., the UE 100 may treat the cell as if the cell status is not barred.

[0079] Some example embodiments are described below using principles and terminology of 5G radio access technology without limiting the example embodiments to 5G radio access technology, however.

[0080] FIG. 3 illustrates a signal flow diagram according to an example embodiment. Although one UE 100 is shown in FIG. 3, it should be noted that the number of UEs may also be different than one. In other words, there may be one or more UEs. In addition, the signaling procedure illustrated in FIG. 3 may be extended and applied according to the actual number of UEs.

[0081] Referring to FIG. 3, at 301, the first cell 121 (or the first access node 104) and the second cell 122 (or the second access node 104B) may exchange information via backhaul signaling. For example, the first cell 121 (or the first access node 104) may provide a wake-up signal configuration to the second cell122 (or the second access node 104B) for the uplink wake-up signal to be used for requesting the OD-S1B1 transmission of the first cell 121. The wake-up signal configuration may indicate, for example, the radio resources to be used for transmitting the wake-up signal.

[0082] Alternatively, the second cell 122 (or the second access node 104B) may generate the wake-up signal configuration for the uplink wake-up signal to be used for requesting the OD-S1B1 transmission of the first cell 121.

[0083] At 302, the UE 100 selects or reselects the first cell 121. The UE 100 monitors system information and possibly paging information from the first cell 121.

[0084] At 303, the UE 100 fails to acquire S1B1 from the first cell 121 after completing the cell selection or cell reselection to the first cell 121.

[0085] At 304, the UE 100 determines or considers the first cell 121 as barred for up to a pre-defined time period (e.g., 300 seconds) due to being unable to acquire the S1B1 from the first cell 121.

[0086] At 305, after barring the first cell (NES cell) 121, the UE 100 selects or reselects the second cell (cell A) 122, and the UE 100 is then camping on the second cell 122 in idle mode or in inactive mode. In other words, the UE 100 switches from the first cell 121 to the second cell 122 for attempting to receive the wake-up signal configuration of the first cell 121 from the second cell 122 before the pre-defined time period expires. The UE 100 monitors the control channel of the second cell 122.

[0087] At 306, the UE 100 receives, from the second cell 122 (or from the second access node 104B), before the pre-defined time period (e.g., 300 seconds) expires, the wake-up signal configuration associated with the wake-up signal for requesting the OD-S1B1 transmission of the first cell 121. The wake-up signal configuration may be carried on, for example, S1B1 or other SIB (SIBx) or an RRC release message of the second cell 122. Alternatively, the wake-up signal configuration may be received from the first cell 121, for example in an RRC release message. Alternatively, the wake-up signal configuration may be pre-defined (e.g., hard-coded at the UE 100, or pre-defined in specifications), in which case the UE100 may not need to receive the wake-up signal configuration from the second cell 122 or from the first cell 121, or the UE 100 may receive an indication or a pointer from the second cell 122 or from the first cell 121 to indicate which wake-up signal configuration to use from the pre-defined wake-up signal configurations.

[0088] The wake-up signal configuration may comprise an identifier, such as a physical cell identity (PCI) of the first cell 121. Herein the wake-up signal configuration is used as an example of an indication, which indicates that the first cell 121 supports OD-S1B1 transmission.

[0089] At 307, based on the wake-up signal configuration, the UE 100 determines, before the pre-defined time period (e.g., 300 seconds) expires, that the first cell 121 supports OD-S1B1 transmission (i.e., that the first cell 121 is a NES cell).

[0090] At 308, based on determining that the first cell 121 supports the OD-S1B1 transmission, the UE 100 determines to include the first cell 121 as a candidate cell for cell selection or cell reselection (or any other idle mode operation) before the pre-defined time period (e.g., 300 seconds) expires. In other words, the UE 100 treats the first cell 121 as if the cell status of the first cell 121 is unbarred, even though the pre-defined time period has not expired yet. Thus, the UE 100 shall not exclude the first cell 121 (barred cell) for any idle mode operation, such as cell selection or cell reselection. The UE 100 may revert or modify the cell status of the first cell 121 from barred to unbarred, so that the first cell 121 can be reselected.

[0091] At 309, based on determining to include the first cell 121 as a candidate cell for cell selection or cell reselection, the UE 100 selects or reselects the first cell 121 before the pre-defined time period (e.g., 300 seconds) expires, and the UE 100 is then camping on the second cell 122 in idle mode or in inactive mode. In other words, the UE 100 does not need to wait for 300 seconds before being able to (re)selectthe first cell 121.

[0092] At 310, while camping on the first cell 121 after the cell (re)selection of 309, the UE 100 may transmit the wake-up signal to the first cell 121 (or to the first access node 104) for requesting the OD-S1B1 transmission ofthe first cell 121. The wake-up signal may be transmitted based on the wake-up signal configuration. The first cell 121 (or the first access node 104) may provide feedback, such as an acknowledgement, to the request.

[0093] At 311, the UE 100 may receive the OD-S1B1 transmission of the first cell 121 from the first cell 121 (or from the first access node 104) based on or in response to transmitting the wake-up signal. The UE 100 may synchronize with the first cell 121 and read and store the on-demand S1B1 of the first cell 121. The on-demand S1B1 may comprise S1B1 information elements, i.e., the minimum system information needed for initial access to the first cell 121.

[0094] The first cell 121 (or the first access node 104) may transmit the on-demand S1B1, for example, by broadcasting the on-demand S1B1, or transmitting the on-demand S1B1 via unicast or groupcast to the UE 100 that requested the on-demand S1B1 via the wake-up signal (i.e., the transmission may be UE-specific or UE-group specific or a broadcast).

[0095] Alternatively, based on receiving the wake-up signal from the UE 100, the first cell 121 (or the first access node 104) may transmit an indication to the second cell 122 (or to the second access node 104B) to transmit the OD-S1B1 of the first cell 121 to the UE 100, and the second cell 122 (or the second access node 104B) may then transmit the OD-S1B1 of the first cell 121 to the UE 100 based on receiving the indication.

[0096] At 312, based on the information comprised in the OD-S1B1 transmission of the first cell 121, the UE 100 may access the first cell 121 (by performing a random-access channel procedure) and establish an RRC connection to the first cell 121.

[0097] FIG. 4 illustrates a signal flow diagram according to an example embodiment. Although one UE 100 is shown in FIG. 4, it should be noted that the number of UEs may also be different than one. In other words, there may be one or more UEs. In addition, the signaling procedure illustrated in FIG.4 may be extended and applied according to the actual number of UEs.

[0098] Referring to FIG. 4, at 401, the first cell 121 (or the first access node 104) and the second cell 122 (or the second access node 104B) may exchangeinformation via backhaul signaling. For example, the first cell 121 (or the first access node 104) may provide a wake-up signal configuration to the second cell 122 (or the second access node 104B) for the uplink wake-up signal to be used for requesting the OD-S1B1 transmission of the first cell 121. The wake-up signal configuration may indicate, for example, the radio resources to be used for transmitting the wake-up signal. Alternatively, or additionally, the first cell 121 (or the first access node 104) may provide, to the second cell 122 (or to the second access node 104B) a configuration for an on-demand S1B1 of the first cell 121.

[0099] Alternatively, the second cell 122 (or the second access node 104B) may generate the wake-up signal configuration for the uplink wake-up signal to be used for requesting the OD-S1B1 transmission of the first cell 121.

[0100] At 402, the UE 100 selects or reselects the first cell 121. The UE 100 monitors system information and possibly paging information from the first cell 121.

[0101] At 403, the UE 100 fails to acquire S1B1 from the first cell 121 after completing the cell selection or cell reselection to the first cell 121.

[0102] At 404, the UE 100 determines or considers the first cell 121 as barred for up to a pre-defined time period (e.g., 300 seconds) due to being unable to acquire the S1B1 from the first cell 121.

[0103] At 405, after barring the first cell (NES cell) 121, the UE 100 selects or reselects the second cell (cell A) 122, and the UE 100 is then camping on the second cell 122 in idle mode or in inactive mode. In other words, the UE 100 switches from the first cell 121 to the second cell 122 for attempting to receive the wake-up signal configuration from the second cell 122 before the pre-defined time period expires. The UE 100 monitors the control channel of the second cell 122.

[0104] At 406, the UE 100 receives, from the second cell 122 (or from the second access node 104B), before the pre-defined time period (e.g., 300 seconds) expires, the wake-up signal configuration associated with the wake-up signal for requesting the OD-S1B1 transmission of the first cell 121. The wake-up signal configuration may be carried on, for example, S1B1 or other SIB (SIBx) or an RRC release message of the second cell 122. Alternatively, the wake-up signalconfiguration may be received from the first cell 121, for example in an RRC release message. Alternatively, the wake-up signal configuration may be pre-defined (e.g., hard-coded at the UE 100, or pre-defined in specifications), in which case the UE 100 may not need to receive the wake-up signal configuration from the second cell 122 or from the first cell 121, or the UE 100 may receive an indication or a pointer from the second cell 122 or from the first cell 121 to indicate which wake-up signal configuration to use from the pre-defined wake-up signal configurations.

[0105] The wake-up signal configuration may comprise an identifier, such as a physical cell identity (PCI) of the first cell 121. Herein the wake-up signal configuration is used as an example of an indication, which indicates that the first cell 121 supports OD-S1B1 transmission.

[0106] At 407, based on the wake-up signal configuration, the UE 100 determines, before the pre-defined time period (e.g., 300 seconds) expires, that the first cell 121 supports OD-S1B1 transmission (i.e., that the first cell 121 is a NES cell).

[0107] At 408, based on determining that the first cell 121 supports the OD-S1B1 transmission, the UE 100 determines to include the first cell 121 as a candidate cell for cell selection or cell reselection (or any other idle mode operation) before the pre-defined time period (e.g., 300 seconds) expires. In other words, the UE 100 treats the first cell 121 as if the cell status of the first cell 121 is unbarred, even though the pre-defined time period has not expired yet. Thus, the UE 100 shall not exclude the first cell 121 (barred cell) for any idle mode operation, such as cell selection or cell reselection. The UE 100 may revert or modify the cell status of the first cell 121 from barred to unbarred, so that the first cell 121 can be reselected.

[0108] At 409, while camping on the second cell 122, the UE 100 may transmit the wake-up signal to the second cell 122 (or to the second access node 104B) for requesting the OD-S1B1 transmission of the first cell 121. The wake-up signal may be transmitted based on the wake-up signal configuration. The second cell 122 (or the second access node 104B) may provide feedback, such as an acknowledgement, to the request.

[0109] At 410, the UE 100 may receive the OD-SIB1 transmission of the first cell 121 from the second cell 122 (or from the second access node 104B) based on or in response to transmitting the wake-up signal. The on-demand S1B1 may comprise S1B1 information elements, i.e., the minimum system information needed for initial access to the first cell 121.

[0110] The second cell 122 (or the second access node 104B) may transmit the on-demand S1B1, for example, by broadcasting the on-demand S1B1, or transmitting the on-demand S1B1 via unicast or groupcast to the UE 100 that requested the on-demand S1B1 via the wake-up signal (i.e., the transmission may be UE-specific or UE-group specific or a broadcast). For example, the OD-S1B1 of the first cell 121 may be multiplexed with S1B1 of the second cell 122. The second cell 122 (or the second access node 104B) may transmit the on-demand S1B1 of the first cell 121 based on (or in response to) receiving the wake-up signal from the UE 100.

[0111] Alternatively, based on receiving the wake-up signal from the UE 100, the second cell 122 (or the second access node 104B) may transmit an indication to the first cell 121 (or to the first access node 104) to transmit the OD- S1B1 of the first cell 121 to the UE 100, and the first cell 121 (or the first access node 104) may then transmit the OD-S1B1 of the first cell 121 to the UE 100 based on receiving the indication.

[0112] At 411, based on the information comprised in the OD-S1B1 transmission of the first cell 121, the UE 100 may access the first cell 121 (by performing a random-access channel procedure) and establish an RRC connection to the first cell 121.

[0113] FIG. 5 illustrates a flow chart according to an example embodiment of a method for cell status and cell reservations with OD-S1B1 operation. The method may be performed by an apparatus 600 depicted in FIG. 6. For example, the apparatus 600 may be, or comprise, or be comprised in, a user equipment (UE) 100, 102.

[0114] Referring to FIG. 5, in block 501, the apparatus 600 determines (a status of) a first cell 121 as barred for up to a pre-defined time period due tobeing unable to acquire a system information block type one (S1B1) from the first cell 121.

[0115] In block 502, the apparatus 600 determines, before the predefined time period expires, whether the first cell 121 supports on-demand S1B1 transmission.

[0116] In block 503, based on determining that the first cell 121 supports the on-demand S1B1 transmission (block 502: yes), the apparatus 600 determines to include the first cell 121 as a candidate cell for an idle mode operation before the pre-defined time period expires. In other words, the apparatus 600 may treat the status of the first cell 121 as if it is unbarred, or the apparatus 600 may modify the status of the first cell 121 from barred to unbarred before the pre-defined time period expires.

[0117] For example, the apparatus 600 may receive, from the first cell 121 or from a second cell 122, an indication indicating that the first cell 121 supports the on-demand S1B1 transmission, and the first cell 121 may be determined to support the on-demand S1B1 transmission based on the indication.

[0118] The idle mode operation may comprise, for example, at least one of: cell selection, cell reselection, public land mobile network (PLMN) selection, stand-alone non-public network (SNPN) selection, or location registration. For example, the determination to include the first cell 121 as a candidate cell for the idle mode operation may comprise determining to include the first cell 121 as a candidate cell for cell selection or cell reselection before the pre-defined time period expires.

[0119] As an example, the indication may comprise a wake-up signal configuration associated with a wake-up signal for requesting the on-demand S1B1 transmission of the first cell 121. The apparatus 600 may switch from the first cell 121 to the second cell 122 for attempting to receive the wake-up signal configuration from the second cell 122 before the pre-defined time period expires. The apparatus 600 may transmit, to the first cell 121 or to the second cell 122, based on the wake-up signal configuration, the wake-up signal for requesting the on-demand S1B1 transmission of the first cell 121, based on determining to includethe first cell as a candidate cell for the idle mode operation before the pre-defined time period expires; and receive the on-demand S1B1 transmission of the first cell 121 from the first cell 121 or from the second cell 122.

[0120] As another example, the indication may be comprised in a master information block (i.e., physical broadcast channel payload) of the first cell 121.

[0121] As another example, the indication may be comprised in downlink control information of the first cell 121.

[0122] As another example, the indication may be comprised in downlink control information of the second cell 122

[0123] Alternatively, in block 504, based on determining that the first cell 121 does not support the on-demand S1B1 transmission (block 502: no), the apparatus 600 determines to exclude the first cell 121 as a candidate cell for the idle mode operation until the pre-defined time period expires. The excluding means that the status of the first cell 121 is maintained as barred until the predefined time period expires.

[0124] For example, the first cell 121 may be determined to notsupport the on-demand S1B1 transmission, if the indication indicating that the first cell 121 supports the on-demand S1B1 transmission is not received from the first cell 121 or from the second cell 122 (e.g., within a pre-defined time window).

[0125] For example, the determination to exclude the first cell 121 as a candidate cell for the idle mode operation may comprise determining to exclude the first cell 121 as a candidate cell for cell selection or cell reselection until the pre-defined time period expires.

[0126] The blocks, related functions, and information exchanges (messages) described above by means of FIGS. 2 to 5 are in no absolute chronological order, and some of them may be performed simultaneously or in an order differing from the described one. Other functions can also be executed between them or within them, and other information may be sent, and / or other rules applied. Some of the blocks or part of the blocks or one or more pieces of information can also be left out or replaced by a corresponding block or part of theblock or one or more pieces of information.

[0127] Herein the terms ‘first cell’ and ‘second cell’ are used to distinguish the cells, and they do not necessarily mean a specific order or specific identifiers of the cells. Similarly, the terms ‘first access node’ and ‘second access node’ are used to distinguish the access nodes, and they do not necessarily mean a specific order or specific identifiers of the access nodes.

[0128] 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.

[0129] FIG. 6 illustrates an example of an apparatus 600 comprising means for performing one or more of the example embodiments (e.g., the operations of the UE 100 in FIG. 3 or 4, or the method of FIG. 5) described above. For example, the apparatus 600 may be an apparatus such as, or comprising, or comprised in, a user equipment (UE) 100, 102.

[0130] The apparatus 600 may comprise a circuitry or a chipset applicable for realizing one or more of the example embodiments described above. For example, the apparatus 600 may comprise at least one processor 610. The at least one processor 610 interprets instructions (e.g., computer program instructions) and processes data. The at least one processor 610 may comprise one or more programmable processors. The at least one processor 610 may comprise programmable hardware with embedded firmware and may, alternatively or additionally, comprise one or more application-specific integrated circuits (ASICs).

[0131] The at least one processor 610 is coupled to at least one memory 620. The at least one processor is configured to read and write data to and from the at least one memory 620. The at least one memory 620 may comprise one or more memory units. The memory units may be volatile or non-volatile. It is to be noted that there may be one or more units of non-volatile memory and one or more units of volatile memory or, alternatively, one or more units of non-volatile memory, or, alternatively, one or more units of volatile memory. Volatile memory may be forexample random-access memory (RAM), dynamic random-access memory (DRAM) or synchronous dynamic random-access memory (SDRAM). Non-volatile memory may be for example read-only memory (ROM), programmable read-only memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash memory, optical storage or magnetic storage. In general, memories may be referred to as non-transitory computer readable media. 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). The at least one memory 620 stores computer readable instructions that are executed by the at least one processor 610 to perform one or more of the example embodiments described above. For example, non-volatile memory stores the computer readable instructions, and the at least one processor 610 executes the instructions using volatile memory for temporary storage of data and / or instructions. The computer readable instructions may refer to computer program code.

[0132] The computer readable instructions may have been pre-stored to the at least one memory 620 or, alternatively or additionally, they may be received, by the apparatus, via an electromagnetic carrier signal and / or may be copied from a physical entity such as a computer program product. Execution of the computer readable instructions by the at least one processor 610 causes the apparatus 600 to perform one or more of the example embodiments described above. That is, the at least one processor and the at least one memory storing the instructions may provide the means for providing or causing the performance of any of the methods and / or blocks described above.

[0133] In one embodiment, the apparatus 600 comprises at least one processor 610, and at least one memory 620 storing instructions that, when executed by the at least one processor 610, cause the apparatus 600 at least to: determine a first cell 121 as barred for up to a pre-defined time period due to being unable to acquire a system information block type one (S1B1) from the first cell 121; determine, before the pre-defined time period expires, whether the first cell 121 supports on-demand S1B1 transmission; and based on determining whetherthe first cell 121 supports the on-demand S1B1 transmission, determine whether to include or exclude the first cell 121 as a candidate cell for an idle mode operation before the pre-defined time period expires.

[0134] In the context of this document, a “memory” or “computer- readable media” or “computer-readable medium” may be any non-transitory media or medium or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. 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).

[0135] The apparatus 600 may further comprise, or be connected to, an input unit 630. The input unit 630 may comprise one or more interfaces for receiving input. The one or more interfaces may comprise for example one or more temperature, motion and / or orientation sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons and / or one or more touch detection units. Further, the input unit 630 may comprise an interface to which external devices may connect to.

[0136] The apparatus 600 may also comprise an output unit 640. The output unit may comprise or be connected to one or more displays capable of rendering visual content, such as a light emitting diode (LED) display, a liquid crystal display (LCD) and / or a liquid crystal on silicon (LCoS) display. The output unit 640 may further comprise one or more audio outputs. The one or more audio outputs may be for example loudspeakers.

[0137] The apparatus 600 further comprises a connectivity unit 650. The connectivity unit 650 enables wireless connectivity to one or more external devices, such as an access node 104, 104B of a radio access network. The connectivity unit 650 comprises at least one transmitter and at least one receiver that may be integrated to the apparatus 600 or that the apparatus 600 may be connected to. The at least one transmitter comprises at least one transmission antenna, and the at least one receiver comprises at least one receiving antenna. The connectivity unit 650 may comprise an integrated circuit or a set of integratedcircuits that provide the wireless communication capability for the apparatus 600. Alternatively, the wireless connectivity may be a hardwired application-specific integrated circuit (ASIC). The connectivity unit 650 may also provide means for performing at least some of the blocks or functions of one or more example embodiments described above. The connectivity unit 650 may comprise one or more components, such as: power amplifier, digital front end (DFE), analog-to- digital converter (ADC), digital-to-analog converter (DAC), frequency converter, (de) modulator, and / or encoder / decoder circuitries, controlled by the corresponding controlling units.

[0138] It is to be noted that the apparatus 600 may further comprise various components not illustrated in FIG. 6. The various components may be hardware components and / or software components.

[0139] 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, 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 (for example firmware) for operation, but the software may not be present when it is not needed for operation.

[0140] 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 computingor network device.

[0141] The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of example embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chipset (for example procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of the systems described herein may be rearranged and / or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

[0142] It will be obvious to a person skilled in the art that, as technology advances, the inventive concept may be implemented in various ways within the scope of the claims. The embodiments are not limited to the example embodiments described above, but may vary within the scope of the claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate, not to restrict, the embodiments.

Claims

CLAIMS1. An apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: determine a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, SIB1, from the first cell; determine, before the pre-defined time period expires, whether the first cell supports on-demand SIB1 transmission; and based on determining whether the first cell supports the on-demand SIB1 transmission, determine whether to include or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires.

2. The apparatus of claim 1, wherein the idle mode operation comprises at least one of: cell selection, cell reselection, public land mobile network selection, stand-alone non-public network selection, or location registration.

3. The apparatus of any preceding claim, caused to: receive, from the first cell or from a second cell, an indication indicating that the first cell supports the on-demand SIB1 transmission, wherein the first cell is determined to support the on-demand SIB1 transmission based on the indication, and wherein the first cell is determined to be included as a candidate cell for the idle mode operation before the pre-defined time period expires, based on determining that the first cell supports the on-demand SIB1 transmission.

4. The apparatus of claim 3, wherein the determination to include the first cell as a candidate cell for the idle mode operation comprises determining toinclude the first cell as a candidate cell for cell selection or cell reselection before the pre-defined time period expires.

5. The apparatus of any of claims 1 to 2, wherein the first cell is determined to not support the on-demand S1B1 transmission, if an indication indicating that the first cell supports the on-demand S1B1 transmission is not received from the first cell or from the second cell, wherein the first cell is determined to be excluded as a candidate cell for the idle mode operation until the pre-defined time period expires, based on determining that the first cell does not support the on-demand S1B1 transmission.

6. The apparatus of claim 5, wherein the determination to exclude the first cell as a candidate cell for the idle mode operation comprises determining to exclude the first cell as a candidate cell for cell selection or cell reselection until the pre-defined time period expires.

7. The apparatus of any of claims 3 to 6, wherein the indication comprises a wake-up signal configuration associated with a wake-up signal for requesting the on-demand S1B1 transmission of the first cell.

8. The apparatus of claim 7, caused to: switch from the first cell to the second cell for attempting to receive the wake-up signal configuration from the second cell before the pre-defined time period expires.

9. The apparatus of any of claims 7 to 8, caused to: transmit, to the first cell or to the second cell, the wake-up signal for requesting the on-demand S1B1 transmission of the first cell, based on determining to include the first cell as a candidate cell for the idle mode operation before the pre-defined time period expires; andreceive the on-demand SIB1 transmission of the first cell from the first cell or from the second cell.

10. The apparatus of any of claims 3 to 6, wherein the indication is comprised in a master information block of the first cell.

11. The apparatus of any of claims 3 to 6, wherein the indication is comprised in downlink control information of the first cell.

12. The apparatus of any of claims 3 to 6, wherein the indication is comprised in downlink control information of the second cell.

13. The apparatus of any preceding claim, wherein the apparatus is a user equipment.

14. A method comprising: determining a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, S1B1, from the first cell; determining, before the pre-defined time period expires, whether the first cell supports on-demand S1B1 transmission; and based on determining whether the first cell supports the on-demand S1B1 transmission, determine whether to include or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires.

15. A non-transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following:determining a first cell as barred for up to a pre-defined time period due to being unable to acquire a system information block type one, S1B1, from the first cell; determining, before the pre-defined time period expires, whether the first cell supports on-demand S1B1 transmission; and based on determining whether the first cell supports the on-demand S1B1 transmission, determine whether to include or exclude the first cell as a candidate cell for an idle mode operation before the pre-defined time period expires.

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