UE procedures for anchor cell failure

Abstract

An apparatus including circuitry configured to determine a failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; and determine a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and provide the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

Description

UE Procedures For Anchor Cell FailureTECHNICAL FIELD

[0001] The examples and non-limiting example embodiments relate generally to communications and, more particularly, to UE procedures for Anchor Cell failure.BACKGROUND

[0002] It is known for a communication device to gain access to a communication network via an access network node.SUMMARY

[0003] In accordance with an aspect, an apparatus includes 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 failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; and determine a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and provide the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

[0004] In accordance with an aspect, an apparatus includes 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: receive, from an anchor cell, an indication that the anchor cell is barred; determine whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and perform a cell selection or cell reselection based on measurements and information acquired.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The foregoing aspects and other features are explained in the following description, taken in connection with the accompanying drawings.

[0006] FIG. 1 is a block diagram of one possible and non-limiting system in which the example embodiments may be practiced.

[0007] FIG. 2 shows an example OD-SIB 1 functional architecture.

[0008] FIG. 3 shows an example message sequence chart.

[0009] FIG. 4A shows an example UE flow chart.

[0010] FIG. 4B shows an example gNB flow chart.

[0011] FIG. 5 is an example apparatus configured to implement the examples described herein.

[0012] FIG. 6 shows a representation of an example of non-volatile memory media used to store instructions that implement the examples described herein.

[0013] FIG. 7 is an example method, based on the examples described herein.

[0014] FIG. 8 is an example method, based on the examples described herein.DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0015] Turning to FIG. 1, this figure shows a block diagram of one possible and non-limiting example in which the examples may be practiced. A user equipment (UE) 110, radio access network (RAN) node 170, and network element(s) 190 are illustrated. In the example of FIG.1, the user equipment (UE) 110 is in wireless communication with a wireless network 100. A UE is a wireless device that can access the wireless network 100. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a module 140, comprising one of or both parts 140-1 and / or 140-2, which may be implemented in a number of ways. The module 140 may be implemented inhardware as module 140-1, such as being implemented as part of the one or more processors 120. The module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user equipment 110 to perform one or more of the operations as described herein. The UE 110 communicates with RAN node 170 via a wireless link 111.

[0016] The RAN node 170 in this example is a base station that provides access for wireless devices such as the UE 110 to the wireless network 100. The RAN node 170 may be, for example, a base station for 5G, also called New Radio (NR). In 5G, the RAN node 170 may be a NG-RAN node, which is defined as either a gNB or an ng-eNB. A gNB is a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface (such as connection 131) to a 5GC (such as, for example, the network element(s) 190). The ng-eNB is a node providing E-UTRA user plane and control plane protocol terminations towards the UE, and connected via the NG interface (such as connection 131) to the 5GC. The NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and distributed unit(s) (DUs) (gNB-DUs), of which DU 195 is shown. Note that the DU 195 may include or be coupled to and control a radio unit (RU). The gNB-CU 196 is a logical node hosting radio resource control (RRC), SDAP and PDCP protocols of the gNB or RRC and PDCP protocols of the en-gNB that control the operation of one or more gNB-DUs. The gNB-CU 196 terminates the Fl interface connected with the gNB-DU 195. The Fl interface is illustrated as reference 198, although reference 198 also illustrates a link between remote elements of the RAN node 170 and centralized elements of the RAN node 170, such as between the gNB-CU 196 and the gNB-DU 195. The gNB-DU 195 is a logical node hosting RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is partly controlled by gNB-CU 196. One gNB-CU 196 supports one or multiple cells. One cell may be supported with one gNB-DU 195, or one cell may be supported / shared with multiple DUs under RAN sharing. The gNB-DU 195 terminates the Fl interface 198 connected with the gNB-CU 196. Note that the DU 195 is considered to include the transceiver 160, e.g., as part of a RU, but some examples of this may have the transceiver 160 as part of a separate RU, e.g., under control of and connected to the DU 195.The RAN node 170 may also be an eNB (evolved NodeB) base station, for LTE (long term evolution), or any other suitable base station or node.

[0017] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N / W I / F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include the processor(s) 152, one or more memories 155, and network interfaces 161. Note that the DU 195 may also contain its own memory / memories and processor(s), and / or other hardware, but these are not shown.

[0018] The RAN node 170 includes a module 150, comprising one of or both parts 150-1 and / or 150-2, which may be implemented in a number of ways. The module 150 may be implemented in hardware as module 150-1, such as being implemented as part of the one or more processors 152. The module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 150 may be implemented as module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance, the one or more memories 155 and the computer program code 153 are configured to, with the one or more processors 152, cause the RAN node 170 to perform one or more of the operations as described herein. Note that the functionality of the module 150 may be distributed, such as being distributed between the DU 195 and the CU 196, or be implemented solely in the DU 195.

[0019] The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. Two or more gNBs 170 may communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards.

[0020] The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for gNB implementation for 5G, with the other elements of the RAN node 170 possibly being physically in a different location from theRRH / DU 195, and the one or more buses 157 could be implemented in part as, for example, fiber optic cable or other suitable network connection to connect the other elements (e.g., a central unit (CU), gNB-CU 196) of the RAN node 170 to the RRH / DU 195. Reference 198 also indicates those suitable network link(s).

[0021] A RAN node / gNB can comprise one or more TRPs to which the methods described herein may be applied. FIG. 1 shows that the RAN node 170 comprises TRP 51 and TRP 52, in addition to the TRP represented by transceiver 160. Similar to transceiver 160, TRP 51 and TRP 52 may each include a transmitter and a receiver. The RAN node 170 may host or comprise other TRPs not shown in FIG. 1.

[0022] A relay node in NR is called an integrated access and backhaul node. A mobile termination part of the IAB node facilitates the backhaul (parent link) connection. In other words, the mobile termination part comprises the functionality which carries UE functionalities. The distributed unit part of the IAB node facilitates the so called access link (child link) connections (i.e. for access link UEs, and backhaul for other IAB nodes, in the case of multi-hop IAB). In other words, the distributed unit part is responsible for certain base station functionalities. The IAB scenario may follow the so called split architecture, where the central unit hosts the higher layer protocols to the UE and terminates the control plane and user plane interfaces to the 5G core network.

[0023] It is noted that the description herein indicates that “cells” perform functions, but it should be clear that equipment which forms the cell may perform the functions. The cell makes up part of a base station. That is, there can be multiple cells per base station. For example, there could be three cells for a single carrier frequency and associated bandwidth, each cell covering one-third of a 360 degree area so that the single base station’s coverage area covers an approximate oval or circle. Furthermore, each cell can correspond to a single carrier and a base station may use multiple carriers. So if there are three 120 degree cells per carrier and two carriers, then the base station has a total of 6 cells.

[0024] The wireless network 100 may include a network element or elements 190 that may include core network functionality, and which provides connectivity via a link or links 181 with a further network, such as a telephone network and / or a data communications network (e.g., the Internet). Such core network functionality for 5G may include location management functions (LMF(s)) and / or access and mobility management function(s) (AMF(S)) and / or userplane functions (UPF(s)) and / or session management function(s) (SMF(s)). Such core network functionality for LTE may include MME (mobility management entity) / SGW (serving gateway) functionality. Such core network functionality may include SON (self- organizing / optimizing network) functionality. These are merely example functions that may be supported by the network element(s) 190, and note that both 5G and LTE functions might be supported. The RAN node 170 is coupled via a link 131 to the network element 190. The link 131 may be implemented as, e.g., an NG interface for 5G, or an SI interface for LTE, or other suitable interface for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N / W I / F(s)) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. Computer program code 173 may include SON and / or MRO functionality 172.

[0025] The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, or a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented, at some level, using hardware such as processors 152 or 175 and memories 155 and 171, and also such virtualized entities create technical effects.

[0026] The computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, non-transitory memory, transitory memory, fixed memory and removable memory. The computer readable memories 125, 155, and 171 may be means for performing storage functions. The processors 120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as nonlimiting examples. The processors 120, 152, and 175 may be means for performing functions, such as controlling the UE 110, RAN node 170, network element(s) 190, and other functionsas described herein.

[0027] In general, the various example embodiments of the user equipment 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback devices having wireless communication capabilities, internet appliances including those permitting wireless internet access and browsing, tablets with wireless communication capabilities, head mounted displays such as those that implement virtual / augmented / mixed reality, as well as portable units or terminals that incorporate combinations of such functions. The UE 110 can also be a vehicle such as a car, or a UE mounted in a vehicle, a UAV such as e.g. a drone, or a UE mounted in a UAV. The user equipment 110 may be a terminal device, such as mobile phone, mobile device, sensor device etc., the terminal device being a device used by the user or not used by the user.

[0028] UE 110, RAN node 170, and / or network element(s) 190, (and associated memories, computer program code and modules) may be configured to implement (e.g. in part) the methods described herein. Thus, computer program code 123, module 140-1, module 140-2, and other elements / features shown in FIG. 1 of UE 110 may implement user equipment related aspects of the examples described herein. Similarly, computer program code 153, module 150-1, module 150-2, and other elements / features shown in FIG. 1 of RAN node 170 may implement gNB / TRP related aspects of the examples described herein. Computer program code 173 and other elements / features shown in FIG. 1 of network element(s) 190 may be configured to implement network element related aspects of the examples described herein.

[0029] Having thus introduced a suitable but non-limiting technical context for the practice of the example embodiments, the example embodiments are now described with greater specificity.

[0030] An Anchor Cell refers to a cell transmitting its own SIB1 regularly as per legacy procedures in e.g. 3GPP Rel 15. A legacy UE shall be able to detect and camp on an Anchor Cell. An Anchor Cell may provide Assistance Information of NES cell(s), e.g., on how to trigger the request for the NES cell on-demand SIB1 or the NES cell’s SIB1. An NES cell refers to a cell in an energy saving state where some procedures / messages may not beperiodically broadcasted but could be requested on demand by the UE, e.g. on-demand SIB1 requested via an uplink (UL) signal. A Cell can transition between the roles of Anchor Cells and NES cells depending on e.g. the NES procedures its hosting gNB triggers for it. gNB (NES) refers to a gNB hosting the NES cell, gNB (Anchor) refers to a gNB hosting the Anchor Cell, NES refers to Network Energy Savings, OD-SIB1 refers to On-Demand SIB1, and WUS refers to an Uplink Wake Up Signal for OD-SIB1.

[0031] Based on the outcome of RAN# 102 meeting, one of objectives (Objective-2) agreed in the Release 19 WID on Network Energy Saving Enhancements (RP -234065) is related to the support of On-Demand SIB1 for UEs in RRC Idle / Inactive states - the objective statement is as below:

[0032] The On-Demand SIB1 functionality calls for 2 types of cells - an Anchor Cell (or Cell-A) and a NES Cell, where the operation of the NES Cell in On-Demand SIB1 (OD-SIB1) mode is assisted by the Anchor Cell.

[0033] 3GPP is specifying the basic procedures to ensure a UE can request and acquire the OD-SIB1 for a NES cell and this should include Anchor Cell failure scenarios.

[0034] Described herein is a method where a UE, despite being indicated that the cell is barred for devices of its capability via the MIB, may determine to attempt to acquire some system information from the cell prior to initiating a cell selection or reselection ((re)selection) procedure.

[0035] An Anchor Cell provides means for a given UE to acquire, e.g., the on-demand SIB1 of a NES cell. As per definition, the NES cell may suspend regular transmission of somesignals / channels / messages (SIB1) to reduce the energy consumed during e.g. low traffic periods. A NES cell could for example transition to the OD-SIB1 mode and use the assistance of an Anchor Cell for the UE to receive information to acquire the NES cell’s SIB1. In this sense, the Anchor Cell plays a very critical role in supporting this NES Cell functionality, i.e., if the Anchor Cell experiences some type of failure or outage, there needs to be some means via which the UE can yet acquire NES cell information to e.g. camp on them. Otherwise, the UE access to the NES Cell will fail, and the Anchor Cell failure would result in no / reduced utilization of the NES capabilities.

[0036] FIG. 2 shows a simplified network architecture for supporting the OD-SIB1 procedure for two alternative designs being discussed in RANI (case 2 (201) on the left and case 3 (203) on the right in FIG. 2).

[0037] In particular, FIG. 2 shows Case 2 201 and Case 3 203. In Case 2 201, Cell A 170- 1 transmits UL WUS Config 210 to UE 110, UE 110 transmits UL WUS (PRACH) 212 to NES Cell 170-2, and NES Cell 170-2 transmits OD-SIB1 214 to UE 110. In Case 3 203, Cell A 170-1 transmits WUS Config 210 to UE 110, UE 110 transmits WUS 216 to Cell A 170-1, and Cell A 170-1 transmits OD-SIB1 218 to UE 110.

[0038] Thus, FIG. 2 shows a simplified network architecture for supporting on-demand SIB1 (OD-SIB1).

[0039] The examples described herein address the scenario where the Anchor Cell (e.g. RAN node 170 or Cell A 170-1) provides at least one user equipment (e.g. UE 110 or a plurality of user equipments (UEs)) assistance for at least one network energy savings cell.

[0040] The assistance provided to the at least one user equipment by the Anchor Cell may comprise an uplink signal configuration that the at least one user equipment uses to request system information for the at least one network energy savings cell. The Anchor Cell may receive, from the at least one user equipment, the request for the system information for the at least one network energy savings cell. The Anchor Cell may transmit, to the at least one user equipment, the system information for the at least one network energy savings cell.

[0041] The assistance provided to the at least one user equipment by the Anchor Cell may comprise system information for the at least one network energy savings cell. The system information for the at least one network energy savings cell may be provided by the AnchorCell to the at least one user equipment with an on-demand system information block 1.

[0042] The Cell A (Anchor Cell) (e.g. Cell A 170-1) and NES Cell (e.g. NES Cell 170-2) are the main roles attributed to NR cells.

[0043] The potential functions of the Anchor Cell (i.e. Cell A) and Anchor gNB for supporting OD-SIB1 operations of a NES cell include the following (1-4): 1) Receiving the WUS Config (case 2) or SIB1 Info (case 3) from the NES Cell or NES gNB over network interfaces (Xn or NG as applicable). In case of split architecture of NG-RAN node serving the cell A and / or the NES cell, also potentially transfer this information over Fl. 2) Sending WUS Config to the UE, e.g. via system information broadcast. 3) Receiving the UL-WUS from the UE. 4) Sending the OD-SIB1 of the NES cell to the UE (case 3), e.g. via system information broadcast, or send an indication over network interfaces (Xn or NG) to the NES cell to broadcast SIB1 (case 2).

[0044] Given these functions, there are multiple effects of Anchor Cell Failure while the Anchor Cell is assisting a NES cell operating in OD-SIB1 mode. Based on the type of failure in the Anchor Cell, the impact could be one or more of: Cell A unable to send WUS Config to the UE, and / or Cell A unable to receive or handle the UL-WUS transmitted by the UE, and / or Cell A unable to broadcast the OD-SIB1.

[0045] Anchor Cell’s failure could result in that cell being barred or inaccessible for the UE - this would result in the NES cell also becoming inaccessible since the UE depends on the Anchor Cell to receive the OD-SIB1 / WUS Config of the NES cell.

[0046] In summary, such a failure in the cell A could impair UEs from receiving the SIB 1 of the NES cell, and as a result the NES cell will become inaccessible. As can be readily observed, this would be a catastrophic situation for the affected UEs since they in the scenario of a single cell A will have no means of accessing the network.

[0047] From a NES perspective the goal would be to transition as many cells as possible to NES states and this can only be facilitated for certain NES states, if Anchor Cells are highly reliable in providing the basic functions for the NES cells and appropriate fallback procedures are enabled for failure cases.

[0048] Not addressing Anchor Cell failures could lead to operators having to tradeoff NESin favor of better end user experience.

[0049] When an Anchor Cell fails, the network could wake up all the associated NES Cells, but this could lead to unnecessarily increase of network energy consumption because, depending on the network deployment and configuration, there may be other suitable Anchor Cells for a given NES Cell. Higher network energy saving (NES) gain can be obtained if only the NES cells for which this is necessary transition out of their NES state.

[0050] Described herein is a framework to enable the UE acquisition of e.g. the on-demand SIB1 of a NES cell (operating in on-demand SIB1 mode with the assistance of an Anchor Cell) when the Anchor Cell fails, for at least certain types of failures. This would allow for minimized impact to UEs (e.g. service availability interruption) while recovery procedures for the Anchor Cell are executed.

[0051] The high-level description of the framework is provided below from the gNB and UE point of view.

[0052] gNB perspective:

[0053] A gNB (gNB-CU / DU) controlling an Anchor Cell detects or is informed (via e.g. O&M interface) of a failure scenario for the Anchor Cell.

[0054] The gNB (gNB-CU / DU) determines whether the reported failure impacts the transmission of Assistance Information related to the NES cell(s) assisted by the failing Anchor Cell. Assistance Information may for example include an UL WUS configuration for the UE to request the NES cell’s SIB1 from the NES Cell or an UL WUS configuration for the UE to request the NES cell’s SIB1 from the Anchor Cell. Other types of Assistance Information are not excluded.

[0055] If the Anchor Cell failure is impacting the ability to provide data services to UEs the Anchor Cell sets its status to barred (e.g. cell barring set in MIB)

[0056] Optionally, MIB / PBCH content may be indicate ‘cell barring’ but ‘NES Cell’s Assistance Information Provisioning continues.”

[0057] Depending on the identified failure type of the Anchor Cell, the gNB (gNB-CU / DU) determines whether it is feasible to continue the provisioning of the NES Cell’s AssistanceInformation via the Anchor Cell despite its failure and while the Anchor Cell’s MIB indicates cell barring (and potentially ‘NES Cell’s Assistance Information Provisioning continues”). If deemed feasible, the cell further determines which transmission mode to use for provisioning the Assistance Information, as follows with Scenario#! and Scenario#2:

[0058] Scenario#! i.e. prior to the failure the NES Cell’s Assistance Information is provided by the Anchor Cell in one or more SIBs (other than SIB1) which is provided on-demand. In this scenario the Anchor Cell either does one of the following (a) or (b) (the choice could be up to network implementation if both are supported by 3 GPP): a) stops broadcasting the Assistance Information in one or more SIBs and instead starts broadcasting it as part of SIB1. In this case contents of normal SIB may be severely truncated since access to the Anchor Cell does not need to be facilitated; b) starts broadcasting the one or more SIBs regularly (stops the on-demand mode), and the gNB (gNB-CU / DU) determines the periodicity of broadcasting of the SIBx carrying the Assistance Information associated with its configured NES Cells.

[0059] The gNB may determine to employ SIB1 transmission of Assistance Information for NES cells which are most frequently requested (based on e.g. historic data). For the remainder of the NES cells, the Assistance Information could be broadcasted via one more other SIBs with each other SIB having a periodicity correlated to a frequency of requested Assistance Information requests.

[0060] If the Assistance Information does not fit all in one SIB or it is decided in 3GPP to split the Assistance Information based on intra frequency and inter frequency, several SIBs may be used to transmit the Assistance Information.

[0061] Scenario#! (i.e. the NES Cell’s Assistance Information is transmitted by the Anchor Cell as part of SIB1 or another one or more SIBs which is transmitted regularly prior to the failure): The cell will then continue with the same operation despite the failure. That is, the Anchor Cell will continue transmitting the SIB1 (and one or more SIBs) periodically, however the periodicity of other SIBs relaying Assistance Information in this scenario may be modified to allow for more frequent broadcasting.

[0062] UE perspective:

[0063] UE is camping on the Anchor Cell and detects that its serving Anchor Cell has transitioned to cell barred status based on the MIB.

[0064] UE further determines that the MIB / PBCH content indicates ‘cell barring’ and ‘NES Cell’s Assistance Information Provisioning continues”. Note that this indication could be optional, and it could be left to the UE determine if the barred cell is an Anchor Cell (based on other methods, such as content of Sis) and whether it should attempt retrieval of Assistance Information for NES cells via this barred Anchor Cell.

[0065] UE determines whether there would be any benefit from attempting to acquire any Assistance Information for cell (re)selection purposes from the Anchor Cell. This determination could be based on if the UE has recently measured other cells which are deemed suitable, and it has recently acquired a valid version of the SIB1 for these other potentially suitable cells.

[0066] If the UE determines it would benefit from Assistance Information to e.g., speed up cell (re)selection the UE may attempt to acquire Anchor Cell SIB1 and potentially other Sis of the Anchor Cell which provide the Assistance Information. The Assistance Information could be e.g. the UL-WUS for NES Cells. Based on SIB1 UE could potentially determine which Assistance Information Sis are required and to avoid having to acquire them all for UE energy saving purposes. These other Sis to be acquired could be based on measurements it has of other cells deemed as potentially suitable.

[0067] UE acquires Assistance Information from the Anchor Cell based on the transmission mode the Anchor Cell advertises.

[0068] FIG. 3 provides a message sequence chart of how the Anchor Cell failure can be handled. In particular, FIG. 3 shows a message sequence 300 between UE 110 and Anchor Cell / node 170-1.

[0069] At 310, a UE is camping on an Anchor Cell. It is assumed that a UE can determine that its serving cell is an Anchor Cell based on e.g. presence of certain SI messages or configuration / information elements within Sis.

[0070] At 320, a gNB detects or is informed (via .e.g. O&M interface or NMS or over any network interface) of a failure scenario associated with an Anchor Cell. The gNB proceeds to determining if the failure reported impacts the delivery of Assistance Information related NES cells associated with the failing Anchor Cell.

[0071] Here Assistance Information here refers to e.g., delivery of an UL WUS configuration of a NES Cell or a UL WUS configuration for the Anchor Cell via which the UE can retrieve information of at least one NES Cell. It may also mean the OD-SIB1 of the NES cell.

[0072] The gNB-CU or gNB-DU could determine that the reported failure does impact the Anchor Cell’s ability to provide the Assistance Information if e.g.: The RACH success rate has been reported as below an established target. Note the target could be preconfigured in the gNB or in the Network Management System(NMS) or based on a percentage of degradation from historical performance. Fl / Xn Transport interface failure: For NES Cells under the control of a different gNB the Anchor Cell gNB would not be able to receive updates on the NES Cell configurations or status if e.g. the Xn interface is experiencing an outage. Similarly, if the NES Cells associated with the Anchor Cell are part of the same gNB but different DU, Fl interface failures could lead to Anchor Cell DU not possessing the latest information of the NES Cells, e.g., changes in UL WUS configuration or updated SIB1 information.

[0073] At 330 the gNB decides to set the Anchor Cell status to barred. Based on the failure type identified for the Anchor Cell, the gNB could determine whether to initiate periodic transmission of the Assistance Information if e.g., the Assistance Information was broadcast on demand before the failure. For example, if the failure is associated with RACH performance degradation and RACH is the means for a UE to trigger the Anchor Cell for UL WUS configuration or OD-SIB1 of the NES cell, the Anchor Cell could broadcast the Assistance Information periodically to facilitate UE acquisition without the need for a UE triggering procedure, UL WUS.

[0074] If the failure is associated with a transport failure which impedes the gNB of obtaining the latest configuration of the NES cells, then the Anchor Cell could refrain from providing any Assistance Information.

[0075] For scenarios where periodic transmission of the Assistance Information is initiated, the periodicity of the transmissions may be determined based on the amount of information assistance that needs to be delivered (e.g. grouping of information of different NES Cells) and number of Anchor Cells associated with each NES cell (if this information is available to the gNB) to attempt to minimize UE cell re-selection times. For example, if no grouping of NES Cell information is employed; and NES Cell# 1 is associated with another 3 Anchor Cells;and NES Cell#2 is associated only with the failing Anchor Cell, the Anchor Cell may determine to broadcast the Assistance Information of NES Cell#2 with higher frequency than NES Cell#l.

[0076] Whether Assistance Information of different NES Cells could be grouped to be transmitted on a single time occasion (e.g. slot) could depend on specifications adopted and the reliability with which the gNB is configured to deliver the Assistance Information. If grouping is possible, NES Cells requiring the same periodicity could be prioritized to be included in the same group.

[0077] At 340 the Anchor Cell transmits it barred status over the MIB. In some embodiments the MIB / PBCH content may indicate the ‘cell barring’ along with an indication that ‘NES Cell’s Assistance Information Provisioning continues. This could be enabled via for example employing the spare bit of the MIB.

[0078] At 350, the UE upon detection of the cell barred status of the Anchor Cell determines whether there would be any benefit from attempting to acquire any Assistance Information for cell (re)selection purposes from the Anchor Cell. This determination could be based on if the UE has: recently measured other cells which are deemed suitable; and it has recently acquired a valid version of the SIB1 for these other potentially suitable cells; or has a valid version of the UL-WUS configuration to obtain the OD-SIB1 from the NES Cells.

[0079] For example: assume UE#1 and UE#2 are in idle mode and their serving cells is an Anchor Cell for other cells in NES state.

[0080] Example#! (1-7):

[0081] 1. UE#1 in idle mode in poor radio conditions, i.e., UE measurements of RSRP andRSRQ of the serving cell are below a predefined threshold which lead the UE to initiate measurements of intra-and inter frequency neighbor cells.

[0082] 2. UE#1 acquires Assistance Information from Anchor Cell to obtain SIB-1 OD of NES cells.

[0083] 3. UE#1 initiates measurements of neighbor cells but none meet cell re-selection criterion.

[0084] 4. Anchor Cell fails and switches to cell barred state and continues to provide Assistance Information.

[0085] 5. UE#1 has recent SIB-1 of other neighbor cells (which can be other Anchor Cells or NES cells)

[0086] 6. UE#1 proceeds to camp on the best of the other cells it has measured and for which it has SIB1.

[0087] 7. In this case UE#1 upon detecting the failed Anchor Cell is barred determines it does not need to see if the Anchor Cell is yet providing any Assistance Information since it already has candidate cells for cell selection

[0088] Example #2 (1-7):

[0089] 1. UE#2 in idle mode in good radio conditions, i.e., UE measurements of RSRP andRSRQ of the serving cell are above a predefined threshold which allow the UE to save power by not needing to perform measurements or by performing relaxed measurements, i.e., UE#2 is not performing frequent measurements.

[0090] 2. UE#2 does not acquire Assistance Information for acquisition of SIB-1 OD of NES cells

[0091] 3. Anchor Cell fails and switches to cell barred state and continues to provide Assistance Information.

[0092] 4. UE#2 does not have a recent SIB-1 of other neighbor cells (which can be other Anchor Cells or NES cells)

[0093] 5. In this case UE#2 upon detecting the failed Anchor Cell is barred determines to continue listening to the Anchor Cell to see if the Anchor Cell is yet providing any Assistance Information, since it has no candidate cells for cell selection

[0094] 6. UE#2 acquires the Assistance Information from the barred Anchor Cell while performing measurements of other cells

[0095] 7. UE#2 now possesses the method to obtain SIB1-OD of NES cells it may have measured and determined as suitable to camp on.

[0096] Example#3 : Anchor Cell failure does not allow it to provide Assistance Information (1-7):

[0097] 1. UE#2 in idle mode in good radio conditions, i.e., UE measurements of RSRP andRSRQ of the serving cell are above a predefined threshold which allow the UE to save power by not needing to perform measurements or by performing relaxed measurements, i.e., UE#2 is not performing frequent measurements.

[0098] 2. UE#2 does not acquire Assistance Information for acquisition of SIB-1 OD of NES cells.

[0099] 3. Anchor Cell fails and switches to cell barred state and does not provide Assistance Information.

[0100] 4. UE#2 does not have a recent SIB-1 of other neighbor cells (which can be other Anchor Cells or NES cells).

[0101] 5. In this case UE#2 upon detecting the failed Anchor Cell is barred determines to continue listening to the Anchor Cell to see if the Anchor Cell is yet providing any Assistance Information, since it has no candidate cells for cell selection.

[0102] 6. UE#2 cannot acquire the Assistance Information from the barred Anchor Cell, but continues to perform measurements of other cells.

[0103] 7. UE#2 will continue to search for a suitable cell for which SIB-1 can be acquired. In this case the UE could select another Anchor Cell or a NES cell for which SIB1-OD is triggered by some other UE which acquired the Assistance Information from some other Anchor Cell.

[0104] In example 2 and 3 when the UE determines to try to acquire the Assistance Information from a barred Anchor Cell, the UE can acquire the timing information of when the cell Assistance Information would be periodically broadcasted via .e.g. SIB1. Since the UE has this timing information the delay impact from acquisition of Assistance Information can be minimized. Furthermore in Example 3, after the UE fails to acquire SIB1 or the Assistance Information XX times (e.g. XX=1 if measurements of the Anchor Cell are good) it could assume the Anchor Cell is not providing the Assistance Information and furtherminimize any delay impacts on the measurements of other cells.

[0105] In example 2 , UE#2 upon detecting that its Anchor Cell is barred could just decide to try to select another cell without attempting to acquire Assistance Information, but the issue arises when there are no suitable neighbor Anchor Cells. The other suitable cells for this UE could be in NES state employing SIB-1 OD. In this case UE#2 could experience an outage and this is where the above scheme could help.

[0106] At 360, if the UE determines it would benefit from Assistance Information to e.g., speed up cell (re)selection the UE may attempt to acquire Anchor Cell SIB1 and potentially other Sis of the barred Anchor Cell. The Assistance Information could be e.g. the UL-WUS for NES Cells.

[0107] Note that until the acquisition of the SIB 1 of the barred Anchor Cell the UE may not know if there is a periodic transmission of the Assistance Information for the NES Cells or for which NES Cells the Assistance Information is periodically transmitted.

[0108] Based on the SIB1, the UE could potentially determine which Assistance Information Sis are required to avoid having to acquire them all for UE energy saving purposes. These other Sis to be acquired could be based on measurements it has of other cells deemed as potentially suitable.

[0109] At 360 the Anchor Cell broadcasts information regarding a modification on the method to acquire the NES Cell information, e.g., from on-demand to periodically broadcast, along with information of how and when to acquire the periodically broadcasted information.

[0110] Note in an Anchor Cell which is set to cell barred there is technically no other traffic in the cell, hence the at least some of the cell DL resources can be used for the periodic transmissions of the Assistance Information.[OHl] At 370, based on acquired Assistance Information from barred Anchor Cell, the UE proceeds to initiate cell (re)selection procedures.

[0112] FIG. 4 A and FIG. 4B provide flow charts from the perspective of the UE 110 and Anchor Cell node 170-1, for which the description is analogous.

[0113] FIG. 4A shows an example UE flow chart for UE 110. At 402, the UE is campingon the Anchor Cell. At 404, the UE decodes an Anchor Cell MIB indicating that the cell is barred. At 406, the UE determines whether Assistance Information is required for cell selection or reselection. In response to the UE determining at 406 that Assistance Information is required for cell selection or reselection (e.g. “Yes”), the method transitions to 408. In response to the UE determining at 406 that Assistance Information is not required for cell selection or reselection (e.g. “No”), the method transitions to 416.

[0114] At 408, the UE acquires SIB1 of the Anchor Cell. At 410, the UE determines whether Assistance Information is being transmitted periodically. In response to the UE determining at 410 that Assistance Information is being transmitted periodically (e.g. “Yes”), the method transitions to 412. In response to the UE determining at 410 that Assistance Information is not being transmitted periodically (e.g. “No”), the method transitions to 416. At 412, the UE determines other Sis to be acquired based on measurements of neighbor cells. At 414, the UE acquires the other Sis. At 416, the UE initiates cell selection or reselection.

[0115] FIG. 4B shows an example Anchor Cell flow chart for the Anchor Cell node 170-1, where the Anchor Cell node 170-1 is for example a gNB. At 422, the Anchor Cell node receives an indication of or determines a failure related to an Anchor Cell. At 424, the Anchor Cell node determines if the failure impacts the Anchor Cell’s ability to provide Assistance Information of NES cells. In response to the Anchor Cell node determining at 424 that the failure does impact the Anchor Cell’s ability to provide information of NES cells (e.g. “Yes”), the method transitions to 426. In response to the Anchor Cell node determining at 424 that the failure does not impact the Anchor Cell’s ability to provide information of NES cells (e.g. “No”), the method transitions to 428.

[0116] At 426, the Anchor Cell node determines whether the Anchor Cell can facilitate the Assistance Information via other methods (e.g. periodic transmissions). In response to the Anchor Cell node determining at 426 that the Anchor Cell can facilitate the Assistance Information via other methods (e.g. periodic transmissions) (e.g. “Yes”), the method transitions to 430. In response to the Anchor Cell node determining at 426 that the Anchor Cell cannot facilitate the Assistance Information via other methods (e.g. periodic transmissions) (e.g. “No”), the method transitions to 428. At 428, the Anchor Cell node operates as per other procedures.

[0117] At 430, the Anchor Cell node sets MIB to indicate the cell is barred. At 432, theAnchor Cell node determines periodicity of transmissions of the Assistance Information for each NES cell or group of NES cells. At 434, the Anchor Cell node initiates periodic transmissions of Assistance Information with scheduling provided via e.g. SIB1.

[0118] Advantages and technical effects of the methods described herein include that the solution attempts to conserve higher NES even when Anchor Cells fail by allowing UEs to determine which NES cells associated with the Anchor Cell need to exit NES state, and assists in improving UE cell (re)selection times when an Anchor Cell fails. From the UE’s perspective, the methods described herein enable them to access an NES cell even when the Anchor Cell fails. This improves the overall user experience in the network.

[0119] The examples described herein may be applicable to 3GPP TS 38.331 and TS 38.304.

[0120] FIG. 5 is an example apparatus 500, which may be implemented in hardware, configured to implement the examples described herein. The apparatus 500 comprises at least one processor 502 (e.g. an FPGA and / or CPU), one or more memories 504 including computer program code 505, the computer program code 505 having instructions to carry out the methods described herein, wherein the at least one memory 504 and the computer program code 505 are configured to, with the at least one processor 502, cause the apparatus 500 to implement circuitry, a process, component, module, or function (implemented with control module 506) to implement the examples described herein. The one or more memories 504 may include a non-transitory memory, a transitory memory, a volatile memory (e.g. RAM), or a non-volatile memory (e.g. ROM).

[0121] Failure procedures 530 implements the examples described herein related to UE and Anchor Cell procedures for Anchor Cell failure.

[0122] The apparatus 500 includes a display and / or VO interface 508, which includes user interface (UI) circuitry and elements, that may be used to display aspects or a status of the methods described herein (e.g., as one of the methods is being performed or at a subsequent time), or to receive input from a user such as with using a keypad, camera, touchscreen, touch area, microphone, biometric recognition, one or more sensors, etc. The apparatus 500 includes one or more communication e.g. network (N / W) interfaces (VF(s)) 510. The communication I / F(s) 510 may be wired and / or wireless and communicate over the Internet / other network(s) via any communication technique including via one or more links 524. The link(s) 524 maybe the link(s) 131 and / or 176 from FIG. 1. The link(s) 131 and / or 176 from FIG. 1 may also be implemented using transceiver(s) 516 and corresponding wireless link(s) 526. The communication I / F(s) 510 may comprise one or more transmitters or one or more receivers.

[0123] The transceiver 516 comprises one or more transmitters 518 and one or more receivers 520. The transceiver 516 and / or communication I / F(s) 510 may comprise standard well-known components such as an amplifier, filter, frequency-converter, (de)modulator, and encoder / decoder circuitries and one or more antennas, such as antennas 514 used for communication over wireless link 526.

[0124] The control module 506 of the apparatus 500 comprises one of or both parts 506-1 and / or 506-2, which may be implemented in a number of ways. The control module 506 may be implemented in hardware as control module 506-1, such as being implemented as part of the one or more processors 502. The control module 506-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the control module 506 may be implemented as control module 506-2, which is implemented as computer program code (having corresponding instructions) 505 and is executed by the one or more processors 502. For instance, the one or more memories 504 store instructions that, when executed by the one or more processors 502, cause the apparatus 500 to perform one or more of the operations as described herein. Furthermore, the one or more processors 502, the one or more memories 504, and example algorithms (e.g., as flowcharts and / or signaling diagrams), encoded as instructions, programs, or code, are means for causing performance of the operations described herein.

[0125] The apparatus 500 to implement the functionality of control 506 may be UE 110, RAN node 170 (e.g. gNB), or network element(s) 190 (e.g. LMF 190). Thus, processor 502 may correspond to processor(s) 120, processor(s) 152 and / or processor(s) 175, memory 504 may correspond to one or more memories 125, one or more memories 155 and / or one or more memories 171, computer program code 505 may correspond to computer program code 123, computer program code 153, and / or computer program code 173, control module 506 may correspond to module 140-1, module 140-2, module 150-1, and / or module 150-2, and communication I / F(s) 510 and / or transceiver 516 may correspond to transceiver 130, antenna(s) 128, transceiver 160, antenna(s) 158, N / W I / F(s) 161, and / or N / W I / F(s) 180. Alternatively, apparatus 500 and its elements may not correspond to either of UE 110, RANnode 170, or network element(s) 190 and their respective elements, as apparatus 500 may be part of a self-organizing / optimizing network (SON) node or other node, such as a node in a cloud.

[0126] Apparatus 500 may correspond to any of the other apparatuses described herein, such as Anchor Cell / node 170-1, or NES cell / node 170-2.

[0127] The apparatus 500 may also be distributed throughout the network (e.g. 100) including within and between apparatus 500 and any network element (such as a network control element (NCE) 190 and / or the RAN node 170 and / or UE 110).

[0128] Interface 512 enables data communication and signaling between the various items of apparatus 500, as shown in FIG. 5. For example, the interface 512 may be one or more buses such as address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. Computer program code (e.g. instructions) 505, including control 506 may comprise object-oriented software configured to pass data or messages between objects within computer program code 505, or computer program code (e.g. instructions) 505, including control 506 may include functional, scripting, or procedural code. The apparatus 500 need not comprise each of the features mentioned, or may comprise other features as well. The various components of apparatus 500 may at least partially reside in a common housing 528, or a subset of the various components of apparatus 500 may at least partially be located in different housings, which different housings may include housing 528.

[0129] FIG. 6 shows a schematic representation of non-volatile memory media 600a (e.g. computer / compact disc (CD) or digital versatile disc (DVD)) and 600b (e.g. universal serial bus (USB) memory stick) and 600c (e.g. cloud storage for downloading instructions and / or parameters 602 or receiving emailed instructions and / or parameters 602) storing instructions and / or parameters 602 which when executed by a processor allows the processor to perform one or more of the steps of the methods described herein. Instructions and / or parameters 1002 may represent a computer readable medium.

[0130] FIG. 7 is an example method 700 based on the examples described herein. At 710, the method includes determining a failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration.At 720, the method includes determining a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration. At 730, the method includes providing the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state. Method 700 may be performed with RAN node 170, Anchor Node 170-1, Anchor Cell 170-1, or apparatus 500.

[0131] FIG. 8 is an example method 800 based on the examples described herein. At 810, the method includes receiving, from an anchor cell, an indication that the anchor cell is barred. At 820, the method includes determining whether to acquire assistance information from an anchor cell for cell selection or cell reselection. At 830, the method includes performing a cell selection or cell reselection based on measurements and information acquired. Method 800 may be performed with UE 110 or apparatus 500.

[0132] The following examples are provided and described herein.

[0133] Example 1. An apparatus including: 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 failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; determine a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and provide the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

[0134] Example 2. The apparatus of example 1, wherein the apparatus is further caused to: determine a periodicity with which to provide the assistance information of the at least one network energy saving cell; and provide the assistance information of the at least one network energy saving cell periodically, based on the determined periodicity; wherein the determinedmethod of providing the assistance information of the at least one network energy saving cell based on the second configuration comprises periodic transmission of the assistance information of the at least one network energy saving cell.

[0135] Example 3. The apparatus of example 2, wherein the periodicity is determined per group of network energy saving cells and the assistance information for each group of network energy saving cells is broadcasted with the respective periodicity determined for each group of the network energy saving cells.

[0136] Example 4. The apparatus of example 3, wherein the grouping of the network energy saving cells is based on at least one of: a frequency carrier of the network energy saving cells, or a frequency of requests of assistance information, or a number of anchor cells associated with the network energy saving cells.

[0137] Example 5. The apparatus of any of examples 2 to 4, wherein the assistance information of the at least one network energy saving cell was provided with the apparatus on-demand based on the first configuration, prior to determining to provide the assistance information of the at least one network energy saving cell periodically based on the second configuration.

[0138] Example 6. The apparatus of any of examples 1 to 5, wherein the apparatus is further caused to: transmit, to at least one user equipment, an indication of the method of providing the assistance information of the at least one network energy saving cell.

[0139] Example 7. The apparatus of any of examples 1 to 6, wherein the assistance information comprises system information of at least one network energy saving cell that is provided to at least one user equipment.

[0140] Example 8. The apparatus of any of examples 1 to 7, wherein the apparatus is further caused to: transmit, to at least one user equipment, an indication that: the anchor cell is barred, and provisioning of the assistance information is broadcasted for at least one of the at least one network energy saving cell.

[0141] Example 9. The apparatus of any of examples 1 to 8, wherein the apparatus is further caused to: stop broadcasting the assistance information of the at least one network energy saving cell as part of a system information block other than a system information block 1; startbroadcasting the assistance information of the at least one network energy saving cell as part of the system information block 1.

[0142] Example 10. The apparatus of example 9, wherein prior to stopping the broadcasting, the assistance information of the at least one network energy saving cell transmitted by the system information block other than the system information block is requested on demand by the user equipment.

[0143] Example 11. The apparatus of any of examples 1 to 10, wherein the apparatus is further caused to: stop providing the assistance information of the at least one network energy saving cell with a system information block on demand; wherein the assistance information of the at least one network energy saving cell is provided with the system information block on demand prior to the failure of the anchor cell; determine a periodicity with which to start broadcasting the assistance information of the at least one network energy saving cell with the system information block regularly; and start broadcasting the assistance information of the at least one network energy saving cell with the system information block regularly based on the determined periodicity, without a request from a user equipment.

[0144] Example 12. The apparatus of any of examples 1 to 11, wherein the apparatus is further caused to: continue providing the assistance information of the at least one network energy saving cell regularly with a given periodicity despite the failure of the anchor cell; wherein the assistance information of the at least one network energy saving cell is provided regularly with the given periodicity prior to the failure of the anchor cell.

[0145] Example 13. An apparatus including: 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: receive, from an anchor cell, an indication that the anchor cell is barred; determine whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and perform a cell selection or cell reselection based on measurements and information acquired.

[0146] Example 14. The apparatus of example 13, wherein the determination to acquire assistance information is based on at least one of: available measurements of candidate cells for cell selection or cell reselection, or available SIB1 information for the candidate cells, or suitability for cell selection or cell reselection of the candidate cells, or an indication ofassistance information being broadcast by the anchor cell, or a capability to decode the assistance information.

[0147] Example 15. The apparatus of example 14, wherein the capability to decode the assistance information comprises a capability of the apparatus to decode assistance information scheduling information.

[0148] Example 16. The apparatus of any of examples 13 to 15, wherein the information acquired comprises the assistance information acquired via the anchor cell, or assistance information acquired via a network energy saving cell with assistance from the anchor cell.

[0149] Example 17. The apparatus of any of examples 13 to 16, wherein the apparatus is further caused to: receive an indication of a method to acquire the assistance information from the anchor cell; wherein the assistance information is acquired from the anchor cell based on the received indication of the method to acquire the assistance information from the anchor cell.

[0150] Example 18. The apparatus of example 17, wherein the apparatus is further caused to: acquire the assistance information from the anchor cell based on a periodic broadcast of the assistance information; wherein the indication of the method to acquire the assistance information from the anchor cell informs the apparatus of assistance information broadcast occasions and periodicity of at least one group of network energy saving cells.

[0151] Example 19. The apparatus of example 18, wherein the apparatus is further caused to: update a method of the apparatus to acquire the assistance information from the anchor cell, from on demand based acquisition to acquisition based on periodic transmissions of the assistance information.

[0152] Example 20. The apparatus of any of examples 13 to 19, wherein the assistance information acquired from the anchor cell comprises system information of at least one network energy saving cell.

[0153] Example 21. The apparatus of any of examples 13 to 20, wherein the apparatus is further caused to: receive, from the anchor cell, an indication that provisioning of the assistance information continues with a broadcast; wherein the assistance information is of at least one network energy saving cell.

[0154] Example 22. The apparatus of example 21, wherein determining whether to acquire the assistance information from the anchor cell for cell selection or cell reselection is performed in response to receiving the indication from the anchor cell that: the anchor cell is barred, or the provisioning of the assistance information continues.

[0155] Example 23. The apparatus of any of examples 13 to 22, wherein the apparatus is further caused to: perform at least one measurement of at least one candidate cell; acquire system information of the at least one candidate cell; determine that the at least one measurement of the at least one candidate cell satisfies a performance criterion; and determine to not acquire the assistance information from the anchor cell for cell selection or cell reselection, in response to: determining that the at least one measurement of the at least one candidate cell satisfies the performance criterion, and having acquired the system information of the at least one candidate cell.

[0156] Example 24. The apparatus of any of examples 13 to 23, wherein the apparatus is further caused to: perform at least one measurement of at least one candidate cell; acquire at least one item of the assistance information from the anchor cell, based on the at least one measurement of the at least one candidate cell.

[0157] Example 25. The apparatus of example 24, where in the apparatus determines to acquire the at least one item of assistance information from the anchor cell based on a prioritization of: measurement timing windows of neighbor cells that neighbor the anchor cell or the apparatus, and transmission occasions of the assistance information from the anchor cell.

[0158] Example 26. The apparatus of example 25, wherein the prioritization of: the measurement timing windows of the neighbor cells that neighbor the anchor cell or the apparatus, and the transmission occasions of the assistance information from the anchor cell, is based on inter-frequency switching times of the apparatus.

[0159] Example 27. The apparatus of any of examples 13 to 26, wherein the apparatus is further caused to: determine that the anchor cell is not providing the assistance information, when the apparatus fails to acquire system information block 1 or the assistance information from the anchor cell for a number of times, wherein the number of times is two or greater; and determine to measure information of at least one other cell, when the apparatus fails to acquirethe system information block 1 or the assistance information from the anchor cell for the number of times that is two or greater.

[0160] Example 28. The apparatus of any of examples 13 to 27, wherein the apparatus is further caused to: determine that at least one measurement of the anchor cell is satisfactory, when the apparatus is able to acquire system information block 1 or the assistance information from the anchor cell after one attempt.

[0161] Example 29. A method including: determining a failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; determining a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and providing the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

[0162] Example 30. A method including: receiving, from an anchor cell, an indication that the anchor cell is barred; determining whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and performing a cell selection or cell reselection based on measurements and information acquired.

[0163] Example 31. An apparatus including: means for determining a failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; means for determining a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and means for providing the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

[0164] Example 32. An apparatus including: means for receiving, from an anchor cell, anindication that the anchor cell is barred; means for determining whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and means for performing a cell selection or cell reselection based on measurements and information acquired.

[0165] Example 33. A computer readable medium including instructions stored thereon for performing at least the following: determining a failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; determining a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and providing the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

[0166] Example 34. A computer readable medium including instructions stored thereon for performing at least the following: receiving, from an anchor cell, an indication that the anchor cell is barred; determining whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and performing a cell selection or cell reselection based on measurements and information acquired.

[0167] References to a ‘computer’, ‘processor’, etc. should be understood to encompass not only computers having different architectures such as single / multi-processor architectures and sequential or parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGAs), application specific circuits (ASICs), signal processing devices and other processing circuitry. References to computer program, instructions, code etc. should be understood to encompass software for a programmable processor or firmware such as, for example, the programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device etc.

[0168] The memories as described herein may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, non-transitory memory, transitory memory, fixed memory and removable memory. The memories may comprise adatabase for storing data.

[0169] 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).

[0170] As used herein, the term ‘circuitry’ may refer to the following: (a) hardware circuit implementations, such as implementations in analog and / or digital circuitry, and (b) combinations of circuits and software (and / or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s) / software including digital signal processor(s), software, and memories that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor s), that require software or firmware for operation, even if the software or firmware is not physically present. As a further example, as used herein, the term ‘circuitry’ would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and / or firmware. The term ‘circuitry’ would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device.

[0171] It should be understood that the foregoing description is only illustrative. Various alternatives and modifications may be devised by those skilled in the art. For example, features recited in the various dependent claims could be combined with each other in any suitable combination(s). In addition, features from different example embodiments described above could be selectively combined into a new example embodiment. Accordingly, this description is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.

[0172] The following acronyms and abbreviations that may be found in the specification and / or the drawing figures are given as follows (the abbreviations and acronyms may be appended / combined with each other or with other characters using e.g. a dash, hyphen, slash, letter, or number, and may be case insensitive):3 GPP third generation partnership project4G fourth generation5G fifth generation5GC 5G core networkAMF access and mobility management functionASIC application-specific integrated circuitCD compact / computer discConfig configurationCPU central processing unitCU central unit or centralized unitDC dual connectivityDL downlinkDSP digital signal processorDU distributed unitDVD digital versatile disc eNB evolved Node B (e.g., an LTE base station)EN-DC E-UTRAN new radio - dual connectivity en-gNB node providing NR user plane and control plane protocol terminations towards the UE, and acting as a secondary node in EN- DCE-UTRA evolved UMTS terrestrial radio access, i.e., the LTE radio access technologyE-UTRAN E-UTRA networkF 1 interface between the CU and the DUFPGA field-programmable gate array gNB generalized node B, base station for 5G / NR, i.e., a node providingNR user plane and control plane protocol terminations towards theUE, and connected via the NG interface to the 5GCIAB integrated access and backhaulI / F interfaceI / O input / outputLMF location management functionLTE long term evolution (4G)MAC medium access controlMIB master information blockMME mobility management entity MRO mobility robustness optimization NCE network control element NES network energy savings, or network energy saving ng or NG new generation ng-eNB new generation eNB NG-RAN new generation radio access network NMS network management system NR new radio N / W network O&M operation and management OD on demand OD-SIB1 on-demand SIB1 Opt. option PBCH physical broadcast channel PDA personal digital assistant PDCP packet data convergence protocol PHY physical layer PRACH physical random access channel RACH random access channel RAM random access memory RAN radio access network RAN# RAN meeting RANI RAN WG1 RAN2 RAN WG2 RAN3 RAN WG3 Rel release RLC radio link control ROM read-only memory RP RAN plenary RRC radio resource control RRM radio resource management RSRP reference signal received powerRSRQ reference signal received qualityRU radio unitRx receive, or receiver, or receptionSDAP service data adaptation protocolSGW serving gatewaySI system information (e.g. Sis)SIB system information block (e.g. SIBx)SIB1 system information block type 1SMF session management functionSON self-organizing / optimizing networkSSB synchronization signal block, or synchronization signal and physical broadcast channel blockTRP transmission reception pointTx transmit, or transmitter, or transmissionUAV unmanned aerial vehicleUE user equipment (e.g., a wireless, typically mobile device)UI user interfaceUL uplinkUMTS Universal Mobile Telecommunications SystemUPF user plane functionUSB universal serial busWG working groupWID work item descriptionWUS wake up signalX2 network interface between RAN nodes and between RAN and the core networkXn network interface between NG-RAN nodes

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 failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; determine a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and provide the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

2. The apparatus of claim 1, wherein the apparatus is further caused to: determine a periodicity with which to provide the assistance information of the at least one network energy saving cell; and provide the assistance information of the at least one network energy saving cell periodically, based on the determined periodicity; wherein the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration comprises periodic transmission of the assistance information of the at least one network energy saving cell.

3. The apparatus of claim 2, wherein the periodicity is determined per group of network energy saving cells and the assistance information for each group of network energy saving cells is broadcasted with the respective periodicity determined for each group of the network energy saving cells.

4. The apparatus of claim 3, wherein the grouping of the network energy saving cells is based on at least one of: a frequency carrier of the network energy saving cells, or a frequency of requests of assistance information, or a number of anchor cells associated with the network energy saving cells.

5. The apparatus of any of claims 2 to 4, wherein the assistance information of the at least one network energy saving cell was provided with the apparatus on-demand based on the first configuration, prior to determining to provide the assistance information of the at least one network energy saving cell periodically based on the second configuration.

6. The apparatus of any of claims 1 to 5, wherein the apparatus is further caused to: transmit, to at least one user equipment, an indication of the method of providing the assistance information of the at least one network energy saving cell.

7. The apparatus of any of claims 1 to 6, wherein the assistance information comprises system information of at least one network energy saving cell that is provided to at least one user equipment.

8. The apparatus of any of claims 1 to 7, wherein the apparatus is further caused to: transmit, to at least one user equipment, an indication that: the anchor cell is barred, and provisioning of the assistance information is broadcasted for at least one of the at least one network energy saving cell.

9. The apparatus of any of claims 1 to 8, wherein the apparatus is further caused to: stop broadcasting the assistance information of the at least one network energy saving cell as part of a system information block other than a system information block 1; start broadcasting the assistance information of the at least one network energy saving cell as part of the system information block 1.

10. The apparatus of claim 9, wherein prior to stopping the broadcasting, the assistance information of the at least one network energy saving cell transmitted by the system information block other than the system information block is requested on demand by the user equipment.

11. The apparatus of any of claims 1 to 10, wherein the apparatus is further caused to: stop providing the assistance information of the at least one network energy saving cell with a system information block on demand; wherein the assistance information of the at least one network energy saving cell is provided with the system information block on demand prior to the failure of the anchor cell; determine a periodicity with which to start broadcasting the assistance information of the at least one network energy saving cell with the system information block regularly; and start broadcasting the assistance information of the at least one network energy saving cell with the system information block regularly based on the determined periodicity, without a request from a user equipment.

12. The apparatus of any of claims 1 to 11, wherein the apparatus is further caused to: continue providing the assistance information of the at least one network energy saving cell regularly with a given periodicity despite the failure of the anchor cell; wherein the assistance information of the at least one network energy saving cell is provided regularly with the given periodicity prior to the failure of the anchor cell.

13. 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: receive, from an anchor cell, an indication that the anchor cell is barred;determine whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and perform a cell selection or cell reselection based on measurements and information acquired.

14. The apparatus of claim 13, wherein the determination to acquire assistance information is based on at least one of: available measurements of candidate cells for cell selection or cell reselection, or available SIB1 information for the candidate cells, or suitability for cell selection or cell reselection of the candidate cells, or an indication of assistance information being broadcast by the anchor cell, or a capability to decode the assistance information.

15. The apparatus of claim 14, wherein the capability to decode the assistance information comprises a capability of the apparatus to decode assistance information scheduling information.

16. The apparatus of any of claims 13 to 15, wherein the information acquired comprises the assistance information acquired via the anchor cell, or assistance information acquired via a network energy saving cell with assistance from the anchor cell.

17. The apparatus of any of claims 13 to 16, wherein the apparatus is further caused to: receive an indication of a method to acquire the assistance information from the anchor cell; wherein the assistance information is acquired from the anchor cell based on the received indication of the method to acquire the assistance information from the anchor cell.

18. The apparatus of claim 17, wherein the apparatus is further caused to: acquire the assistance information from the anchor cell based on a periodic broadcast of the assistance information;wherein the indication of the method to acquire the assistance information from the anchor cell informs the apparatus of assistance information broadcast occasions and periodicity of at least one group of network energy saving cells.

19. The apparatus of claim 18, wherein the apparatus is further caused to: update a method of the apparatus to acquire the assistance information from the anchor cell, from on demand based acquisition to acquisition based on periodic transmissions of the assistance information.

20. The apparatus of any of claims 13 to 19, wherein the assistance information acquired from the anchor cell comprises system information of at least one network energy saving cell.

21. The apparatus of any of claims 13 to 20, wherein the apparatus is further caused to: receive, from the anchor cell, an indication that provisioning of the assistance information continues with a broadcast; wherein the assistance information is of at least one network energy saving cell.

22. The apparatus of claim 21, wherein determining whether to acquire the assistance information from the anchor cell for cell selection or cell reselection is performed in response to receiving the indication from the anchor cell that: the anchor cell is barred, or the provisioning of the assistance information continues.

23. The apparatus of any of claims 13 to 22, wherein the apparatus is further caused to: perform at least one measurement of at least one candidate cell; acquire system information of the at least one candidate cell; determine that the at least one measurement of the at least one candidate cell satisfies a performance criterion; and determine to not acquire the assistance information from the anchor cell for cell selection or cell reselection, in response to: determining that the at least one measurement of the at least one candidate cell satisfies the performance criterion, and having acquired thesystem information of the at least one candidate cell.

24. The apparatus of any of claims 13 to 23, wherein the apparatus is further caused to: perform at least one measurement of at least one candidate cell; acquire at least one item of the assistance information from the anchor cell, based on the at least one measurement of the at least one candidate cell.

25. The apparatus of claim 24, where in the apparatus determines to acquire the at least one item of assistance information from the anchor cell based on a prioritization of: measurement timing windows of neighbor cells that neighbor the anchor cell or the apparatus, and transmission occasions of the assistance information from the anchor cell.

26. The apparatus of claim 25, wherein the prioritization of: the measurement timing windows of the neighbor cells that neighbor the anchor cell or the apparatus, and the transmission occasions of the assistance information from the anchor cell, is based on interfrequency switching times of the apparatus.

27. The apparatus of any of claims 13 to 26, wherein the apparatus is further caused to: determine that the anchor cell is not providing the assistance information, when the apparatus fails to acquire system information block 1 or the assistance information from the anchor cell for a number of times, wherein the number of times is two or greater; and determine to measure information of at least one other cell, when the apparatus fails to acquire the system information block 1 or the assistance information from the anchor cell for the number of times that is two or greater.

28. The apparatus of any of claims 13 to 27, wherein the apparatus is further caused to: determine that at least one measurement of the anchor cell is satisfactory, when the apparatus is able to acquire system information block 1 or the assistance information from the anchor cell after one attempt.

29. A method comprising: determining a failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; determining a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and providing the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

30. A method comprising: receiving, from an anchor cell, an indication that the anchor cell is barred; determining whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and performing a cell selection or cell reselection based on measurements and information acquired.

31. An apparatus comprising: means for determining a failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; means for determining a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and means for providing the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of theat least one network energy saving cell based on the second configuration in a cell barred state.

32. An apparatus comprising: means for receiving, from an anchor cell, an indication that the anchor cell is barred; means for determining whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and means for performing a cell selection or cell reselection based on measurements and information acquired.

33. A computer readable medium comprising instructions stored thereon for performing at least the following: determining a failure that impacts an ability of an anchor cell to provide assistance information of at least one network energy saving cell based on a first configuration; determining a method of providing the assistance information of the at least one network energy saving cell based on a second configuration, in response to determining the failure that impacts the ability of the anchor cell to provide the assistance information of the at least one network energy saving cell based on the first configuration; and providing the assistance information of the at least one network energy saving cell, based on the determined method of providing the assistance information of the at least one network energy saving cell based on the second configuration in a cell barred state.

34. A computer readable medium comprising instructions stored thereon for performing at least the following: receiving, from an anchor cell, an indication that the anchor cell is barred; determining whether to acquire assistance information from an anchor cell for cell selection or cell reselection; and performing a cell selection or cell reselection based on measurements and information acquired.

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