SSB type adaptation for network energy saving

Abstract

A method includes receiving, by a user equipment (UE) in a radio resource control (RRC) idle or RRC inactive state, a first message from a first cell, the first message including an indication that the first cell is switched from a first synchronization signal block (SSB) mode to a second SSB mode. The UE bars the first cell, and switches to a second cell for communication.

Description

SSB TYPE ADAPTATION FOR NETWORK ENERGY SAVINGFIELD

[0001] Various example embodiments relate generally to wireless networks and, more particularly, for a method and apparatus for synchronization signal block (SSB) adaptation for network energy saving.BACKGROUND

[0002] In the case of a need to change the type of synchronization signal block (SSB) from a cell defining SSB (CD-SSB) to a non cell defining SSB (NCD-SSB), a system information (SI) update may be performed by user equipments (UEs) in a radio resource control (RRC) idle / inactive state.

[0003] In various cases, it may take significant time for a UE in the RRC idle / inactive state to identify that a cell has transitioned from a CD-SSB state to an NCD-SSB state.SUMMARY

[0004] In an aspect of the present disclosure, a method includes receiving, by a user equipment (UE) in a radio resource control (RRC) idle or RRC inactive state, a first message from a first cell, the first message including an indication that the first cell is switched from a first synchronization signal block (SSB) mode to a second SSB mode. The UE bars the first cell, and switches to a second cell for communication.

[0005] In an aspect of the method, the first message is a dynamic indication for SSB adaptation message.

[0006] In an aspect of the method, the first message includes a value indicated in a master information block (MIB) of the SSB for a ssb-SubcarrierOffset indicating the first cell is operating in the second SSB mode.

[0007] In an aspect of the method, the first SSB mode is a cell-defining SSB (CD-SSB) mode and the second SSB mode is a non-cell-defining SSB (NCD-SSB) mode.

[0008] In an aspect of the method, the method further includes determining, by the UE, that the first cell is operating in the second mode.

[0009] In an aspect of the method, the method further includes deleting, by the UE, a stored first system information block (SIB) version.

[0010] In an aspect of the method, the UE is not in a discontinuous reception (DRX) mode.

[0011] In an aspect of the present disclosure, a method includes determining, by a first cell, to switch from a first synchronization signal block (SSB) mode to a second SSB mode. The first cell transmits a first message to a user equipment (UE), the first message including an indication that the first cell is switched from first SSB mode to a second SSB mode. The first cell switches from the first SSB mode to the second SSB mode, and transmits a second message in the second SSB mode to the UE.

[0012] In an aspect of the method, the first message is a dynamic indication for SSB adaptation message.

[0013] In an aspect of the method, the first SSB mode is a cell-defining SSB (CD-SSB) mode and the second SSB mode is a non-cell-defining SSB (NCD-SSB) mode.

[0014] In an aspect of the method, the second message is an NCD-SSB broadcasting message.

[0015] In an aspect of the method, the method further includes determining, by the first cell, to switch from the second SSB mode back to the first SSB mode.

[0016] In an aspect of the present disclosure, a UE includes at least one processor and at least one memory storing instructions which, when executed by the at least one processor, causes the UE at least to perform any of the foregoing methods.

[0017] In an aspect of the present disclosure, an apparatus includes at least one processor and at least one memory storing instructions which, when executed by the at least one processor, causes the apparatus at least to perform any of the foregoing methods.

[0018] In an aspect of the present disclosure, a processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform any of the foregoing methods.

[0019] According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Some example embodiments will now be described with reference to the accompanying drawings.

[0021] FIG. 1 is a diagram of an example embodiment of wireless networking between a network system and a user equipment (UE), according to one illustrated aspect of the disclosure;

[0022] FIG. 2 is a diagram of example components of a network system, according to one illustrated aspect of the disclosure;

[0023] FIG. 3 is a diagram of an example embodiment of signals and operations among a UE and a cell according to one illustrated aspect of the disclosure;

[0024] FIG. 4 is a diagram of an example embodiment of components of a UE or of a network apparatus, according to one illustrated aspect of the present disclosure.DETAILED DESCRIPTION

[0025] In the following description, certain specific details are set forth in order to provide a thorough understanding of disclosed aspects. However, one skilled in the relevant art will recognize that aspects may be practiced without one or more of these specific details or with other methods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the aspects.

[0026] Reference throughout this specification to “one aspect” or “an aspect” means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, the appearances of the phrases “in one aspect” or “in an aspect” in various places throughout this specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more aspects.

[0027] Embodiments described in the present disclosure may be implemented in wireless networking apparatuses, such as, without limitation, apparatuses utilizing Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), 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, enhanced LTE (eLTE), 5G New Radio (5G NR), 5G Advance, 6G (and beyond) and 802.1 lax (Wi-Fi 6), among other wireless networking systems. The term ‘eLTE’ here denotes the LTE evolution that connects to a 5G core. LTE is also known as evolved UMTS terrestrial radio access (EUTRA) or as evolved UMTS terrestrial radio access network (EUTRAN).

[0028] The present disclosure may use the term “serving network device” to refer to a network node or network device (or a portion thereof) that services a UE. As used herein, the terms “transmit to,” “receive from,” and “cooperate with,” (and their variations) include communications that may or may not involve communications through one or more intermediate devices or nodes. The term “acquire” (and its variations) includes acquiring in the first instance or reacquiring after the first instance. The term “connection” may mean a physical connection or a logical connection.

[0029] The present disclosure uses 5G NR as an example of a wireless network and may use smartphones and / or extended reality headsets as an example of UEs. It is intended and shall be understood that such examples are merely illustrative, and the present disclosure is applicable to other wireless networks and user equipment.

[0030] FIG. 1 is a diagram depicting an example of wireless networking between a network system 100 and a user equipment (UE) 150. The network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network equipment 130 (e.g., test equipment). The network nodes 120 will be described in more detail below. As used herein, the term “network apparatus” may refer to any component of the network system 100, such as the server 110, the network node 120, the network equipment 130, any component(s) of the foregoing, and / or any other component(s) of the network system 100. Examples of network apparatuses include, without limitation, apparatuses implementing aspects of 5G NR, among others. The present disclosure describes embodiments related to 5GNR and embodiments that involve aspects defined by 3rd Generation Partnership Project (3GPP). However, it is contemplated that embodiments relating to other wireless networking technologies are encompassed within the scope of the present disclosure.

[0031] The following description provides further details of examples of network nodes. In a 5G NR network, a gNodeB (also known as gNB) may include, e.g., a node that provides new radio (NR) user plane and control plane protocol terminations towards the UE and that is connected via a NG interface to the 5G core (5GC), e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 3.2, which is hereby incorporated by reference herein.

[0032] A gNB supports various protocol layers, e.g., Layer 1 (LI) - physical layer, Layer 2 (L2), and Layer 3 (L3).

[0033] The layer 2 (L2) of NR is split into the following sublayers: Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP) and Service Data Adaptation Protocol (SDAP), where, e.g.: o The physical layer offers to the MAC sublayer transport channels; o The MAC sublayer offers to the RLC sublayer logical channels; o The RLC sublayer offers to the PDCP sublayer RLC channels; o The PDCP sublayer offers to the SDAP sublayer radio bearers; o The SDAP sublayer offers to 5GC quality of service (QoS) flows; o Control channels include broadcast control channel (BCCH) and physical control channel (PCCH).

[0034] Layer 3 (L3) includes, e.g., radio resource control (RRC), e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 6, which is hereby incorporated by reference herein.

[0035] A gNB central unit (gNB-CU) includes, e.g., a logical node hosting, e.g., radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) protocols of the gNB or RRC and PDCP protocols of the en-gNB, that controls the operation of one or more gNB distributed units (gNB-DUs). The gNB-CU terminates the Fl interface connected with the gNB-DU. A gNB-CU may also be referred to herein as a CU, a central unit, a centralized unit, or a control unit.

[0036] A gNB Distributed Unit (gNB-DU) includes, e.g., a logical node hosting, e.g., radio link control (RLC), media access control (MAC), and physical (PHY) layers of the gNB or en- gNB, and its operation is partly controlled by the gNB-CU. One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface connected with the gNB-CU. A gNB-DU may also be referred to herein as DU or a distributed unit.

[0037] As used herein, the term “network node” may refer to any of a gNB, a gNB-CU, or a gNB-DU, or any combination of them. A RAN (radio access network) node or network node such as, e.g., a gNB, gNB-CU, or gNB-DU, or parts thereof, may be implemented using, e.g., an apparatus with at least one processor and / or at least one memory with processor-readable instructions (“program”) configured to support and / or provision and / or process CU and / or DUrelated functionality and / or features, and / or at least one protocol (sub-)layer of a RAN (radio access network), e.g., layer 2 and / or layer 3. Different functional splits between the central and distributed unit are possible. An example of such an apparatus and components will be described in connection with FIG. 4 below.

[0038] The gNB-CU and gNB-DU parts may, e.g., be co-located or physically separated. The gNB-DU may even be split further, e.g., into two parts, e.g., one including processing equipment and one including an antenna. A central unit (CU) may also be called baseband unit / radio equipment controller / cloud-RAN / virtual-RAN (BBU / REC / C-RAN / V-RAN), open-RAN (O- RAN), or part thereof. A distributed unit (DU) may also be called remote radio head / remote radio unit / radio equipment / radio unit (RRH / RRU / RE / RU), or part thereof. Hereinafter, in various example embodiments of the present disclosure, a network node, which supports at least one of central unit functionality or a layer 3 protocol of a radio access network, may be, e.g., a gNB-CU. Similarly, a network node, which supports at least one of distributed unit functionality or a layer 2 protocol of the radio access network, may be, e.g., a gNB-DU.

[0039] A gNB-CU may support one or multiple gNB-DUs. A gNB-DU may support one or multiple cells and, thus, could support a serving cell for a user equipment (UE) or support a candidate cell for handover, dual connectivity, and / or carrier aggregation, among other procedures.

[0040] The user equipment (UE) 150 may be or include a wireless or mobile device, an apparatus with a radio interface to interact with a RAN (radio access network), a smartphone, an in-vehicle apparatus, an loT device, or a M2M device, among other types of user equipment. Such UE 150 may include: at least one processor; and at least one memory including program code; where the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform certain operations, such as, e.g., RRC connection to the RAN. An example of components of a UE will be described in connection with FIG. 5. In embodiments, the UE 150 may be configured to generate a message (e.g., including a cell ID) to be transmitted via radio towards a RAN (e.g., to reach and communicate with a serving cell). In embodiments, the UE 150 may generate and transmit and receive RRC messages containing one or more RRC PDUs (packet data units). Persons skilled in the art will understand RRC protocol as well as other procedures a UE may perform.

[0041] With continuing reference to FIG. 1, in the example of a 5G NR network, the network system 100 provides one or more cells, which define a coverage area of the network system 100.As described above, the network system 100 may include a gNB of a 5G NR network or may include any other apparatus configured to control radio communication and manage radio resources within a cell. As used herein, the term “resource” may refer to radio resources, such as a resource block (RB), a physical resource block (PRB), a radio frame, a subframe, a time slot, a sub-band, a frequency region, a sub-carrier, a beam, etc. In embodiments, the network node 120 may be called a base station.

[0042] FIG. 1 provides an example and is merely illustrative of a network system 100 and a UE 150. Persons skilled in the art will understand that the network system 100 includes components not illustrated in FIG. 1 and will understand that other user equipment may be in communication with the network system 100.

[0043] FIG. 2 is a block diagram of example components of the network system 100 of FIG. 1. A 5G NR network may be described as an example of the network system 100, and it is intended that aspects of the following description shall be applicable to other types of network systems, as well. The network system may operate in accordance with the signals and connections shown in FIG. 1 such that the UE 150 is in communication with the network system 100 through the radio access network 225. Additionally, the network system may be divided into user plane components and functions and control plane components and functions, as shown and described herein. Unless indicated otherwise, the terms “component”, “function”, and “service” may be used interchangeably herein, and they may refer to and be implemented by instructions executed by one or more processors.

[0044] Example functions of the components are described below. The example functions are merely illustrative, and it shall be understood that additional operations and functions may be performed by the components described herein. Additionally, the connections between components may be virtual connections over service-based interfaces such that any component may communicate with any other component. In this manner, any component may act as a service “producer,” for any other component that is a service “consumer,” to provide services for network functions.

[0045] For example, a core network 210 is described in the control plane of the network system. The core network 210 may include an authentication server function (AUSF) 211, an access and mobility function (AMF) 212, and a session management function (SME) 213. The core network 210 may also include a network slice selection function (NSSF) 214, a networkexposure function (NEF) 215, a network repository function (NRF) 216, and a unified data management function (UDM) 217, which may include a uniform data repository (UDR) 224.

[0046] Additional components and functions of the core network 210 may include an application function 218, policy control function (PCF) 219, network data analytics function (NWDAF) 220, analytics data repository function (ADRF) 221, management data analytics function (MDAF) 222, and operations and management function (0AM) 223.

[0047] The user plane includes the UE 150, a radio access network (RAN) 225, a user plane function (UPF) 226, and a data network (DN) 227. The RAN 225 may include one or more components described in connection with FIG. 1, such as one or more network nodes. However, the RAN 225 may not be limited to such components. The UPF 226 provides connection for data being transmitted over the RAN 225. The DN 226 identifies services from service providers, Internet access, and third party services, for example.

[0048] The AMF 212 processes connection and mobility tasks. The AUSF 211 receives authentication requests from the AMF 212 and interacts with UDM 217 to authenticate and validate network responses for determination of successful authentication. The SMF 213 conducts packet data unit (PDU) session management, as well as manages session context with the UPF 226.

[0049] The NSSF 214 may select a network slicing instance (NSI) and determine the allowed network slice selection assistance information (NSSAI). This selection and determination is utilized to set the AMF 212 to provide service to the UE 150. The NEF 215 secures access to network services for third parties to create specialized network services. The NRF 216 acts as a repository to store network functions to allow the functions to register with and discover each other.

[0050] The UDM 217 generates authentication vectors for use by the AUSF 211 and ADM 212 and provides user identification handling. The UDM 217 may be connected to the UDR 224 which stores data associated with authentication, applications, or the like. The AF 218 provides application services to a user (e.g., streaming services, etc.). The PCF 219 provides policy control functionality. For example, the PCF 219 may assist in network slicing and mobility management, as well as provide quality of service (QoS) and charging functionality.

[0051] The NWDAF 220 collects data (e.g., from the UE 150 and the network system) to perform network analytics and provide insight to functions that utilize the analytics in theproviding of services. The ADRF 221 allows the storage, retrieval, and removal of data and analytics by consumers. The MDAF 222 provides additional data analytics services for network functions. The OAM 223 provides provisioning and management processing functions to manage elements in or connected to the network (e.g., UE 150, network nodes, etc.).

[0052] FIG. 2 is merely an example of components of a network system, and variations are contemplated to be within the scope of the present disclosure. In embodiments, the network system may include other components not illustrated in FIG. 2. In embodiments, the network system may not include every component illustrated in FIG. 2. In embodiments, the components and connections may be implemented with different connections than those illustrated in FIG. 2. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0053] Although further detail will be provided below, a method is described herein for synchronization signal block (SSB) type adaptation for network energy saving. In various embodiments, a UE receives information relating to a cell switching from a cell-defining SSB (CD-SSB) type to a non cell-defining SSB (NCD-SSB) type. In various embodiments, the UE discontinues or bars the cell and deletes prior versions of the system information block 1 (SIB1) that it has stored.

[0054] In various embodiments, a cell that provides initial access is associated to a CD-SSB (e.g., an SSB associated with a remaining minimum system information (RMSI) (SIB1)), located on a synchronization raster (as in 3GPP TS 38.300 5.2.4). UEs (e.g., legacy / non Rell9 UEs) in a radio resource control (RRC) idle / inactive mode may use such a cell for camping, since it can support procedures such as cell selection, cell reselection (as per clause 9.2.1, 3GPP TS 38.300).

[0055] In various embodiments, UEs in RRC connected mode can use the cell as a primary cell (PCell) and may need CD-SSB (e.g., for re-establishing RRC connection). Therefore, the periodicity of SSB in such a cell, in various embodiments, is not a value higher than 20ms as it may have a negative impact to those UEs attempting to perform initial cell (re-)selection as they may not be able to find SSBs of the cell, and thus the cell, as expected. In various embodiments, a UE that does not find an SSB within a 20ms window may conclude that the SSB was not transmitted and moves to another frequency.

[0056] In various embodiments, a cell not supporting initial access may be associated with a NCD-SSB only, (an SSB not associated with an RMSI). This cell may be used as a secondary cell(SCell) of a UE in RRC connected mode. The NCD-SSB can then support procedures for UEs in RRC connected mode, such as L1 / L3 measurements, T / F synchronization, etc.

[0057] Adapting the periodicity of an SSB that is not CD-SSB in the time domain to longer values (e.g., 40ms, 80ms, 160ms), may not impact legacy UEs, since they do not perform initial cell selection based on those SSBs, while all sync info can be acquired by the PCell. Therefore, adapting NCD-SSBs as in an SCell may be of minimal impact to legacy UEs, especially if the NCD-SSB is not in the sync raster (e.g., is not detectable to legacy UEs).

[0058] In various embodiments, a UE can determine if the SSB is CD-SSB or NCD-SSB based on the value of parameter ssb-SubcarrierOffset (as per 3GPP TS 38.331, which is kssB in TS 38.213) transmitted in the master information block (MIB). If the value indicates that control resource set (CORESET) for common search space (CSS) that is used to schedule SIB1 is not present, the SSB is not associated with SIB1.

[0059] Accordingly, as mentioned above, a cell may transition from a cell providing initial access to a cell that does not provide initial access. For example, when the number of UEs trying to access the network is low, a cell providing initial access to UEs (e.g., cells with CD-SSBs, can switch to a cell not providing initial access, such as to a cell with NCD-SSBs) for network energy saving purposes.

[0060] Conventional techniques for a UE to determine that a cell has transitioned may include an SI update procedure. In some cases, SI update / acquisition procedure does not require the UE to re-acquire the MIB and determine the current value of ssb-SubcarrierOffset, so the UE does not know that the SSB has changed to NCD-SSB and that SIB1 is not transmitted anymore.

[0061] In other cases, the UE applies the SI acquisition procedure only from the start of the next modification period or from the start of the next eDRX acquisition period boundary, respectively, which may cause additional delay to the process before the UE re-acquires the MIB indicating absence of SIB1, using its battery power to eventually switch to another cell.

[0062] The UE, therefore, may only realize that SIB1 is not transmitted with much delay, perform unnecessary procedures using its battery power and is eventually obliged to switch to another cell.

[0063] In various embodiments, therefore, a method is described herein where the network (e.g., the initial cell or network apparatus) sends an indication to UEs to dynamically inform themabout the SSB type change. In various embodiments, the network may also use the same dynamic indication to instruct UEs to delete any versions of SIB1 they have stored.

[0064] In various embodiments, when a UE in RRC idle / inactive mode detects, receives and decodes the dynamic indication sent by the network, it identifies that the cell has stopped operating with a CD-SSB and is now operating with an NCD-SSB, deletes any version of SIB1 it has stored, and treats the cell as if the cell status indicates a barring status.

[0065] In various embodiments, a cell providing initial access cell regularly transmits CD- SSBs.

[0066] Accordingly, the value of parameter ssb-SubcarrierOffset in the MIB indicates that SIB1 is transmitted in the cell. In various embodiments, system information is also periodically broadcasted by the cell. Moreover, thanks to the RMSI transmissions, the cell is providing random access channel (RACH) occasions for UEs performing initial cell selection to access the cell.

[0067] The CD-SSBs are transmitted with a periodicity up to the one assumed by the UE for initial cell selection. Such a cell is detectable by UEs in any RRC state and provides initial access to UEs.

[0068] FIG. 3 is a diagram of an example embodiment of signals and operations among a UE and a cell according to one illustrated aspect of the disclosure. In various embodiments, the components depicted in FIG. 3 may correspond to similar components described above in FIGS. 1 and 2. It will be understood that a described signal may have associated operations and a described operation may have associated signals.

[0069] As shown in FIG. 3, a Rel.19 UE (e.g. , UE) is camping in a cell providing initial access (e.g., a first cell) and is in RRC idle or RRC inactive mode.

[0070] At operation 301, the first cell transmits a CD-SSB broadcast message to the UE and the UE receives the CD-SSB broadcast message.

[0071] At operation 302, the cell decides to switch from CD-SSB to NCD-SSB (e.g., as described above). At operation 303, the UE is not in a discontinuous reception (DRX) mode.

[0072] Upon determining to switch from CD-SSB to NCD-SSB, at operation 304, the cell transmits a dynamic indication for SSB adaptation message to the UE and the UE receives the dynamic indication for SSB adaptation message. In various embodiments, the dynamic indication for SSB adaptation message includes or is interpreted as an indication for the UE to delete the SIB1 version that the UE has stored, and a new value of the SSB type (NCD-SSB or CD-SSB).The new value indicates that SIB1 is not transmitted in the cell. In various embodiments, the dynamic indication for SSB adaptation may be, for example, via LI signaling such as a group common DCI format that can be received by all the UEs in the cell.

[0073] The network applies the S SB-type adaptation (e.g., broadcasts according to new SSB type), for example, a few slots after sending the dynamic indication to the UEs. Accordingly, at operation 305, the cell transmits an NCD-SSB broadcast message to the UE and the UE may receive the NCD-SSB broadcast message.

[0074] At operation 306, the UE determines based on the dynamic indication (304) that the cell is switching from CD-SSB transmission to NCD-SSB transmission. In various embodiments, the UE may read the new value of ssb-SubcarrierOffset in of the MIB of the NCD-SSB (305) and / or obtain the information that cell has switched SSB type to NCD-SSB from the dynamic indication (304). In various embodiments, if the UE is not in DRX state, the UE may receive the dynamic indication for SSB adaptation at a time instance when UEs in RRC idle / inactive mode are receiving signals from the gNB, (e.g., during the first paging occasion after the network has sent the dynamic indication). Accordingly, the UE understands that the SSB is not associated with an RMSI and that the cell is not providing RACH occasions for UEs performing initial cell selection to access the cell, and that the SSB type is NCD-SSB, the stored version of SIB1, if any, is not valid anymore, and that the UE can neither access the cell nor perform any other idle mode operation.

[0075] Accordingly, at operation 307, the UE understands the cell works with NCD-SSB. At operation 308, the UE deletes any prior version of SIB1. At operation 309, the UE bars the cell.

[0076] At operation 310, the UE switches to another cell.

[0077] In various embodiments, there may exist RRC idle / inactive Rell9 UEs in the DRX state when the dynamic indication for SSB adaptation is sent at operation 304. Such UEs may not receive the dynamic indication and may continue monitoring for SSB and may not find the new SSB of this cell. In various embodiments, if such UE does not find the SSB in the previously configured time / frequency resources (e.g., based on the SSB-received-power) the UE may deduce that it has to resync with the new SSB pattern and read the new MIB. When doing so, it may understand that the cell has switched to transmission of NCD-SSB only.

[0078] RRC idle / inactive legacy UEs in any DRX state when the dynamic indication is sent will not be able decode it, thus will not be informed about absence of SIB1 proactively. It willmonitor for SSBs and after reading MIB it will realize it may not be able to find SIB1. The legacy UE may then follow the legacy procedure of cell re-selection. In various embodiments, if a legacy UE does not acquire SIB1 for a period (e.g., 300 sec) it may bar the cell.

[0079] In various embodiments, any UE in an RRC connected state, Rell9 or legacy, that uses the cell as an SCell when the dynamic indication is sent, may continue using the cell.

[0080] In various embodiments, any UE in RRC connected state, Rell9 or legacy, that uses the cell as a PCell when the dynamic indication is sent, may continue using the cell if they do not need SI. In case they need to acquire SI, they may perform handover.

[0081] The operations of FIG. 3 are merely illustrative, and variations are contemplated to be within the scope of the present disclosure. In embodiments, the operations may include other operations not illustrated in FIG. 3. In embodiments, the operations may not include every operation illustrated in FIG. 3. In embodiments, the operations may be implemented in a different order than that illustrated in FIG. 3. Such and other embodiments are contemplated to be within the scope of the present disclosure. Persons of skill in the art will appreciate that, although various example components are described as perform various functions, other components may perform those functions described in FIG. 3.

[0082] In various embodiments, the SSB adaptation may be enabled in a network with at least two frequency layers, one of which is the coverage layer that always provides initial cell selection to idle / inactive UEs with CD-SSB. The SSB adaptation may be applied in a frequency layer that provides additional capacity to UEs (e.g., a frequency layer other than the coverage layer).

[0083] In various embodiments, if the cell determines to transition again from a cell broadcasting NCD-SSB to a cell broadcasting CD-SSB, it may transmit a dynamic indication to Rell 9 UEs in the RRC connected state with the dynamic indication including at least the new value for the ssb-SubcarrierOffset in the MIB of the SSB. In various embodiments, the new value indicates that SIB1 is transmitted in the cell.

[0084] In various embodiments, the network may transmit the dynamic indication N times in sync with the first paging occasions of Rell 9 UEs that operate with different (e)DRX cycles (e.g., with various combinations of ns and nAndPagingFrameOffset) while preserving network energy saving gains. Thus, if the UE is in DRX state when the first dynamic indication is sent, it may receive a repetition of it in its first paging occasion after the first dynamic indication is sent.

[0085] In various embodiments, the network may indicate new time / frequency resources where the UE can find the SSB together with SSB type (e.g., in or out of the sync raster for NCD- SSBs) or a new value for the transmission periodicity of SSB. In various embodiments, the new time / frequency resources may be included in the dynamic indication sent by the network.

[0086] In various embodiments, the network may configure two or more SSB configurations to the UEs. For example, these configurations may include at least a value of ssb-SubcarrierOffset, the indication to delete the saved version of SIB1 and optionally time / frequency resources to find the new SSB, ssb-PositionsInBurst to indicate (e.g., spatial adaptation of SSBs in different configurations). Dynamic indication of LI signaling may be used to indicate which configuration is used in the cell.

[0087] In various embodiments, the UE may be refrained from performing any unnecessary procedure related to the SI update. Thus, the UE battery may be preserved from using power / consuming energy for these unnecessary procedures.

[0088] In various embodiments, the UE may re-select to a new cell and regain network service within a smaller time window than with the SI update procedure.

[0089] In various embodiments, a cell that changed from CD-SSB to NCD-SSB may be able to save power due to fewer transmissions (e.g., of SIB1 which may be energy consuming for the network). Moreover, with a longer NCD-SSB periodicity used in the cell, more energy may be saved from the fewer transmissions of SSB. Additionally, fewer / scarcer transmission of these reference signals may enable the gNB to enter deeper sleep states.

[0090] In various embodiments, the cell may switch the type of the transmitted SSB in a faster and more dynamic way than with SI adaptation and achieve a trade-off between achieving network energy saving gain and serving UEs quality.

[0091] The following describes operations from the perspective of a UE. From such a perspective, a method may include receiving, by the UE in a radio resource control (RRC) idle or RRC inactive state, a first message from a first cell, the first message including an indication that the first cell is switched from a first synchronization signal block (SSB) mode to a second SSB mode. The UE bars the first cell, and switches to a second cell for communication.

[0092] The following describes operations from the perspective of a first cell. In various embodiments, an apparatus (e.g., network apparatus) of the first cell may perform the operations described herein. From such a perspective, a method may include determining, by the first cell, toswitch from a first synchronization signal block (SSB) mode to a second SSB mode. The first cell transmits a first message to a user equipment (UE), the first message including an indication that the first cell is switched from first SSB mode to a second SSB mode. The first cell switches from the first SSB mode to the second SSB mode, and transmits a second message in the second SSB mode to the UE.

[0093] Referring now to FIG. 4, there is shown a block diagram of example components of a UE or a network apparatus (e.g., of a RAN or a core network). The apparatus includes an electronic storage 410, a processor 420, a network interface 440, and a memory 450. The various components may be communicatively coupled with each other. The processor 420 may be and may include any type of processor, such as a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a System- on- Chip (SoC), or any other type of processor. The memory 450 may be a volatile type of memory, e.g., RAM, or a non-volatile type of memory, e.g., NAND flash memory. The memory 450 includes processor-readable instructions that are executable by the processor 420 to cause the apparatus to perform various operations, including those mentioned herein, such as the operations described in FIG. 3.

[0094] The electronic storage 410 may be and include any type of electronic storage used for storing data, such as hard disk drive, solid state drive, optical disc, and / or other non-transitory computer-readable mediums, among other types of electronic storage. The electronic storage 410 stores processor-readable instructions for causing or configured for causing the apparatus to perform its operations and also stores data associated with such operations, such as storing data relating to 5 G NR standards, among other data. The network interface 440 may implement wireless networking technologies such as 5G NR and / or other wireless networking technologies.

[0095] The components shown in FIG. 5 are merely examples, and persons skilled in the art will understand that an apparatus includes other components not illustrated and may include multiples of any of the illustrated components. Such and other embodiments are contemplated to be within the scope of the present disclosure. For example, a transmitter and a receiver may be included as components for transmitting and receiving signals.

[0096] Further embodiments of the present disclosure include the following examples.

[0097] Example 1.1. A user equipment (UE), comprising:means for receiving, by the UE in a radio resource control (RRC) idle or RRC inactive state, a first message from a first cell, the first message including an indication that the first cell is switched from a first synchronization signal block (SSB) mode to a second SSB mode; means for barring, by the UE, the first cell; and means for switching, by the UE, to a second cell for communication.

[0098] Example 1.2. The UE of example 1.1, wherein the first message is a dynamic indication for SSB adaptation message.

[0099] Example 1.3. The UE as in any one of examples 1.1 or 1.2, wherein the first message includes a value indicated in a master information block (MIB) of the SSB for a ssb- SubcarrierOffset indicating the first cell is operating in the second SSB mode.

[0100] Example 1.4. The UE as in any one of examples 1.1 to 1.3, wherein the first SSB mode is a cell-defining SSB (CD-SSB) mode and the second SSB mode is a non-cell-defining SSB (NCD-SSB) mode.

[0101] Example 1.5. The UE as in any one of examples 1.1 to 1.4, further comprising means for determining, by the UE, that the first cell is operating in the second mode.

[0102] Example 1.6. The UE as in any one of examples 1.1 to 1.5, further comprising means for deleting, by the UE, a stored first system information block (SIB) version.

[0103] Example 1.7. The UE as in any one of examples 1.1 to 1.6, wherein the UE is not in a discontinuous reception (DRX) mode.

[0104] Example 2.1. An apparatus, comprising: means for determining, by a first cell, to switch from a first synchronization signal block (SSB) mode to a second SSB mode; means for transmitting, by the first cell, a first message to a user equipment (UE), the first message including an indication that the first cell is switched from first SSB mode to a second SSB mode; means for switching, by the first cell, from the first SSB mode to the second SSB mode; and means for transmitting, by the first cell, a second message in the second SSB mode to the UE.

[0105] Example 2.2. The apparatus of example 2.1, wherein the first message is a dynamic indication for SSB adaptation message.

[0106] Example 2.3. The apparatus as in any one of examples 2.1 or 2.2, wherein the first SSB mode is a cell-defining SSB (CD-SSB) mode and the second SSB mode is a non-cell-defining SSB (NCD-SSB) mode.

[0107] Example 2.4. The apparatus as in any one of examples 2.1 to 2.3, wherein the second message is an NCD-SSB broadcasting message.

[0108] Example 2.5. The apparatus as in any one of examples 2.1 to 2.4, further comprising determining, by the first cell, to switch from the second SSB mode back to the first SSB mode.

[0109] The embodiments and aspects disclosed herein are examples of the present disclosure and may be embodied in various forms. For instance, although certain embodiments herein are described as separate embodiments, each of the embodiments herein may be combined with one or more of the other embodiments herein. Specific structural and functional details disclosed herein are not to be interpreted as limiting, but as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. Like reference numerals may refer to similar or identical elements throughout the description of the figures.

[0110] The phrases “in an aspect,” “in aspects,” “in various aspects,” “in some aspects,” or “in other aspects” may each refer to one or more of the same or different aspects in accordance with this present disclosure. The phrase “a plurality of’ may refer to two or more.

[0111] In various embodiments, the terms “first message” and “second message”, as well as any subsequent messages may refer to any messages that are transmitted or received in an order and are not necessarily limited to any particular message.

[0112] The phrases “in an embodiment,” “in embodiments,” “in various embodiments,” “in some embodiments,” or “in other embodiments” may each refer to one or more of the same or different embodiments in accordance with the present disclosure. A phrase in the form “A or B” means “(A), (B), or (A and B).” A phrase in the form “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C) ”

[0113] Any of the herein described methods, programs, algorithms or codes may be converted to, or expressed in, a programming language or computer program. The terms “programming language” and “computer program,” as used herein, each include any language used to specify instructions to a computer, and include (but is not limited to) the following languages and theirderivatives: Assembler, Basic, Batch files, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, metalanguages which themselves specify programs, and all first, second, third, fourth, fifth, or further generation computer languages. Also included are database and other data schemas, and any other meta- languages. No distinction is made between languages which are interpreted, compiled, or use both compiled and interpreted approaches. No distinction is made between compiled and source versions of a program. Thus, reference to a program, where the programming language could exist in more than one state (such as source, compiled, object, or linked) is a reference to any and all such states. Reference to a program may encompass the actual instructions and / or the intent of those instructions.

[0114] While aspects of the present disclosure have been shown in the drawings, it is not intended that the present disclosure be limited thereto, as it is intended that the present disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular aspects. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. A method, comprising: receiving, by a user equipment (UE) in a radio resource control (RRC) idle or RRC inactive state, a first message from a first cell, the first message including an indication that the first cell is switched from a first synchronization signal block (SSB) mode to a second SSB mode; barring, by the UE, the first cell; and switching, by the UE, to a second cell for communication.

2. The method of claim 1, wherein the first message is a dynamic indication for SSB adaptation message.

3. The method as in any one of claims 1 or 2, wherein the first message includes a value indicated in a master information block (MIB) of the SSB for a ssb-SubcarrierOffset indicating the first cell is operating in the second SSB mode.

4. The method as in any one of claims 1 to 3, wherein the first SSB mode is a celldefining SSB (CD- SSB) mode and the second SSB mode is a non-cell-defining SSB (NCD-SSB) mode.

5. The method as in any one of claims 1 to 4, further comprising determining, by the UE, that the first cell is operating in the second mode.

6. The method as in any one of claims 1 to 5, further comprising deleting, by the UE, a stored first system information block (SIB) version.

7. The method as in any one of claims 1 to 6, wherein the UE is not in a discontinuous reception (DRX) mode.

8. A method, comprising: determining, by a first cell, to switch from a first synchronization signal block (SSB) mode to a second SSB mode; transmitting, by the first cell, a first message to a user equipment (UE), the first message including an indication that the first cell is switched from first SSB mode to a second SSB mode; switching, by the first cell, from the first SSB mode to the second SSB mode; and transmitting, by the first cell, a second message in the second SSB mode to the UE.

9. The method of claim 8, wherein the first message is a dynamic indication for SSB adaptation message.

10. The method as in any one of claims 8 or 9, wherein the first SSB mode is a celldefining SSB (CD- SSB) mode and the second SSB mode is a non-cell-defining SSB (NCD-SSB) mode.

11. The method as in any one of claims 8 to 10, wherein the second message is an NCD-SSB broadcasting message.

12. The method as in any one of claims 8 to 11, further comprising determining, by the first cell, to switch from the second SSB mode back to the first SSB mode.

13. A user equipment (UE), comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, causes the UE at least to perform: receiving, by the UE in a radio resource control (RRC) idle or RRC inactive state, a first message from a first cell, the first message including an indication that the first cell is switched from a first synchronization signal block (SSB) mode to a second SSB mode; barring, by the UE, the first cell; and switching, by the UE, to a second cell for communication.

14. An apparatus, comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, causes the apparatus at least to perform: determining, by a first cell, to switch from a first synchronization signal block (SSB) mode to a second SSB mode; transmitting, by the first cell, a first message to a user equipment (UE), the first message including an indication that the first cell is switched from first SSB mode to a second SSB mode; switching, by the first cell, from the first SSB mode to the second SSB mode; and transmitting, by the first cell, a second message in the second SSB mode to the UE.

15. A processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform a method as in any one of claims 1 to 12.

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