Signaling to support multicast-broadcast services (MBS) in cells with activated network energy savings mode

Abstract

A method includes receiving, by a user device from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receiving, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and performing, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

Description

SIGNALING TO SUPPORT MULTICAST-BROADCAST SERVICES (MBS) IN CELLS WITH ACTIVATED NETWORK ENERGY SAVINGS MODETECHNICAL FIELD[1] This description relates to wireless communications.BACKGROUND[2] A communication system may be a facility that enables communication between two or more nodes or devices, such as fixed or mobile communication devices. Signals can be carried on wired or wireless carriers.[3] An example of a cellular communication system is an architecture that is being standardized by the 3rd Generation Partnership Project (3GPP). A recent development in this field is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. E-UTRA (evolved UMTS Terrestrial Radio Access) is the air interface of 3GPP's Long Term Evolution (LTE) upgrade path for mobile networks. In LTE, base stations or access points (APs), which are referred to as enhanced Node AP (eNBs), provide wireless access within a coverage area or cell.In LTE, mobile devices, or mobile stations are referred to as user equipments (UE). LTE has included a number of improvements or developments. Aspects of LTE are also continuing to improve.[4] 5G New Radio (NR) development is part of a continued mobile broadband evolution process to meet the requirements of 5G, similar to earlier evolution of 3G and 4G wireless networks. In addition, 5G is also targeted at the new emerging use cases in addition to mobile broadband. A goal of 5G is to provide significant improvement in wireless performance, which may include new levels of data rate, latency, reliability, and security. 5G NR may also scale to efficiently connect the massive Internet of Things (loT) and may offer new types of mission-critical services. For example, ultra-reliable and low-latency communications (URLLC) devices may require high reliability and very low latency. 6G and other networks are also being developed.SUMMARY[5] A method may include receiving, by a user device from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receiving, by the user device from the first cell, a messageindicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and performing, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.[6] An apparatus may include at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: receive, by a user device from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receive, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and perform, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.[7] A method may include transmitting, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmitting, by the network node associated with the first cell to at least a first user device, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.[8] An apparatus may include at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: transmit, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmit, by the network node associated with the first cell to at least a first user device, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.[9] Other example embodiments are provided or described for each of the example methods, including: means for performing any of the example methods; a non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are configured to cause a computing system to perform any of the example methods; and an apparatus including at least one processor, and at leastone memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform any of the example methods.

[0010] The details of one or more examples of embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. l is a block diagram of a wireless network.

[0012] FIG. 2 is a flow chart illustrating operation of a UE (or user device) according to an example embodiment.

[0013] FIG. 3 is a flow chart illustrating operation of a gNB (or network node) according to an example embodiment.

[0014] FIG. 4 is a diagram illustrating an operation of a system according to embodiments 1-2.

[0015] FIG. 5 is a diagram illustrating example embodiment 3.

[0016] FIG. 6 is a diagram illustrating example embodiment 4.

[0017] FIG. 7 is a diagram illustrating example embodiment 5.

[0018] FIG. 8 is a block diagram of a wireless station or node (e.g., UE, user device, AP,BS, eNB, gNB, RAN node, network node, TRP, or other node) 1300 according to an example embodiment.DETAILED DESCRIPTION

[0019] FIG. 1 is a block diagram of a wireless network 130. In the wireless network 130 of FIG. 1, user devices 131, 132, 133 and 135, which may also be referred to as mobile stations (MSs) or user equipment (UEs), may be connected (and in communication) with a base station (BS) 134, which may also be referred to as an access point (AP), an enhanced Node B (eNB), a gNB or a network node. The terms user device and user equipment (UE) may be used interchangeably. A BS may also include or may be referred to as a RAN (radio access network) node, and may include a portion of a BS or a portion of a RAN node, such as (e.g., such as a centralized unit (CU) and / or a distributed unit (DU) in the case of a split BS or split gNB). At least part of the functionalities of a BS (e.g., access point (AP), base station (BS) or (e)Node B (eNB), gNB, RAN node) may also be carried out by any node, server or host which may be operably coupled to a transceiver, such as a remote radio head. BS (or AP) 134 provides wireless coverage within a cell 136, including to user devices (or UEs) 131,132, 133 and 135. Although only four user devices (or UEs) are shown as being connected or attached to BS 134, any number of user devices may be provided. BS 134 is also connected to a core network 150 via a SI interface 151. This is merely one simple example of a wireless network, and others may be used.

[0020] A base station (e.g., such as BS 134) is an example of a radio access network (RAN) node within a wireless network. A BS (or a RAN node) may be or may include(or may alternatively be referred to as), e.g., an access point (AP), a gNB, an eNB, or portion thereof (such as a central / centralized unit (CU) and / or a distributed unit (DU) in the case of a split BS or split gNB), or other network node.

[0021] Some functionalities of the communication network may be carried out, at least partly, in a central / centralized unit, CU, (e.g., server, host or node) operationally coupled to distributed unit, DU, (e.g., a radio head / node). Thus, 5G networks architecture may be based on a so-called CU-DU split. The gNB-CU (central node) may control a plurality of spatially separated gNB-DUs, acting at least as transmit / receive (Tx / Rx) nodes. In some examples, the gNB-DUs (also referred to as a DU) may comprise e.g., a radio link control (RLC), medium access control (MAC) layer and a physical (PHY) layer, whereas the gNB- CU (also referred to as a CU) may comprise the layers above RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) and an internet protocol (IP) layers. Other functional splits are possible too.

[0022] According to an illustrative example, a BS node (e.g., BS, eNB, gNB, CU / DU, . . .) or a radio access network (RAN) may be part of a mobile telecommunication system. A RAN (radio access network) may include one or more BSs or RAN nodes that implement a radio access technology, e.g., to allow one or more UEs to have access to a network or core network. Thus, for example, the RAN (RAN nodes, such as BSs or gNBs) may reside between one or more user devices or UEs and a core network. According to an example embodiment, each RAN node (e.g., BS, eNB, gNB, CU / DU, ...) or BS may provide one or more wireless communication services for one or more UEs or user devices, e.g., to allow the UEs to have wireless access to a network, via the RAN node. Each RAN node or BS may perform or provide wireless communication services, e.g., such as allowing UEs or user devices to establish a wireless connection to the RAN node, and sending data to and / or receiving data from one or more of the UEs. For example, after establishing a connection to a UE, a RAN node or network node (e.g., BS, eNB, gNB, CU / DU, . . .) may forward data to the UE that is received from a network or the core network, and / or forward data received from the UE to the network or core network. RAN nodes or network nodes (e.g., BS, eNB,gNB, CU / DU, . . .) may perform a wide variety of other wireless functions or services, e.g., such as broadcasting control information (e.g., such as system information or on-demand system information) to UEs, paging UEs when there is data to be delivered to the UE, assisting in handover of a UE between cells, scheduling of resources for uplink data transmission from the UE(s) and downlink data transmission to UE(s), sending control information to configure one or more UEs, and the like. These are a few examples of one or more functions that a RAN node or BS may perform.

[0023] A user device or user node (user terminal, user equipment (UE), mobile terminal, handheld wireless device, etc.) may refer to a portable computing device that includes wireless mobile communication devices operating either with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (MS), a mobile phone, a cell phone, a smartphone, a personal digital assistant (PDA), a handset, a device using a wireless modem (alarm or measurement device, etc.), a laptop and / or touch screen computer, a tablet, a phablet, a game console, a notebook, a vehicle, a sensor, and a multimedia device, as examples, or any other wireless device. It should be appreciated that a user device may also be (or may include) a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network.

[0024] Also, a user node may include a user equipment (UE), a user device, a user terminal, a mobile terminal, a mobile station, a mobile node, a subscriber device, a subscriber node, a subscriber terminal, or other user node. For example, a user node may be used for wireless communications with one or more network nodes (e.g., gNB, eNB, BS, AP, CU, DU, CU / DU) and / or with one or more other user nodes, regardless of the technology or radio access technology (RAT). In LTE (as an illustrative example), core network 150 may be referred to as Evolved Packet Core (EPC), which may include a mobility management entity (MME) which may handle or assist with mobility / handover of user devices between BSs, one or more gateways that may forward data and control signals between the BSs and packet data networks or the Internet, and other control functions or blocks. Other types of wireless networks, such as 5G (which may be referred to as New Radio (NR)) may also include a core network.

[0025] In addition, the techniques described herein may be applied to various types of user devices or data service types, or may apply to user devices that may have multiple applications running thereon that may be of different data service types. New Radio (5G) development may support a number of different applications or a number of different dataservice types, such as for example: machine type communications (MTC), enhanced machine type communication (eMTC), Internet of Things (loT), and / or narrowband loT user devices, enhanced mobile broadband (eMBB), and ultra-reliable and low-latency communications (URLLC). Many of these new 5G (NR) - related applications may require generally higher performance than previous wireless networks.

[0026] loT may refer to an ever-growing group of objects that may have Internet or network connectivity, so that these objects may send information to and receive information from other network devices. For example, many sensor type applications or devices may monitor a physical condition or a status, and may send a report to a server or other network device, e.g., when an event occurs. Machine Type Communications (MTC, or Machine to Machine communications) may, for example, be characterized by fully automatic data generation, exchange, processing and actuation among intelligent machines, with or without intervention of humans. Enhanced mobile broadband (eMBB) may support much higher data rates than currently available in LTE.

[0027] Ultra-reliable and low-latency communications (URLLC) is a new data service type, or new usage scenario, which may be supported for New Radio (5G) systems. This enables emerging new applications and services, such as industrial automations, autonomous driving, vehicular safety, e-health services, and so on. 3 GPP targets in providing connectivity with reliability corresponding to block error rate (BLER) of 10-5 and up to 1 ms U-Plane (user / data plane) latency, by way of illustrative example. Thus, for example, URLLC user devices / UEs may require a significantly lower block error rate than other types of user devices / UEs as well as low latency (with or without requirement for simultaneous high reliability). Thus, for example, a URLLC UE (or URLLC application on a UE) may require much shorter latency, as compared to an eMBB UE (or an eMBB application running on a UE).

[0028] The techniques described herein may be applied to a wide variety of wireless technologies or wireless networks, such as 5G (New Radio (NR)), cmWave, and / or mmWave band networks, loT, MTC, eMTC, eMBB, URLLC, 6G, etc., or any other wireless network or wireless technology. These example networks, technologies or data service types are provided only as illustrative examples.

[0029] A network node (e.g., RAN node, gNB CU / DU, or other network node) or a cell may enter or activate (or transition to) a network energy saving (NES) mode in order to conserve power. A NES mode is a mode of operation in which the gNB (or other network node) or cell may operate at a diminished operational capacity, in one or more ways or aspects.

[0030] A cell (or gNB) may transition to a network energy savings (NES) mode of operation in order to conserve power or energy, e.g., during periods of low resource usage. A NES mode of operation may include a mode for the cell (or gNB) in which the cell operates at a reduced operational level or capacity in one or more respects. For example, in a NES mode of operation, various time, frequency, spatial and / or power domain techniques may be used to reduce energy consumption by the cell. For example, in a NES mode of operation, the cell may shut down or turn off, either continuously, or intermittently: one or more channels (where the cell is not transmitting and / or not receiving on one or more channels), one or more carriers (e.g., where the cell is not transmitting and / or not receiving on one or more carriers), one or more beams (e.g., where the cell is not transmitting and / or receiving via one or more beams or reference signals), or other resources. Also, for example, in some cases, an NES mode of operation may include the use of discontinuous transmission (DTX) and / or discontinuous reception (DRX) at the UE, wherein UE(s) that are connected to the cell are in sleeping mode most of the time (not receiving or transmitting) to conserve energy, and then periodically (at scheduled times) may wake up to transmit data to the cell or receive data from the cell. For example, if a cell places or configures all of the UEs that are connected to it into a DTX / DRX mode, then this may allow the cell to operate at a reduced capacity or reduced operational level to conserve energy. A non-NES mode of operation for a cell or gNB may refer to a mode of operation that is not a NES mode of operation, e.g., a mode in which the cell is not operating in a reduced capacity or reduced operational level.

[0031] A cell (or gNB) may, for example, transition (e.g., from a non-NES mode of operation) to a NES mode of operation when a cell load (e.g., an amount of traffic, an amount of connected UEs connected to the cell and / or a number of connected UEs that have been transmitting data within a past period of time, or other cell load) is less than a threshold. For example, a cell may activate (or transition to) NES mode of operation during late night hours when cell load for that cell is very low. The UEs in that area may use or connect to other / neighbor cells during this time period.

[0032] According to an example embodiment, a UE running or executing one or more high throughput applications may be impacted when a cell transitions from a non-NES mode of operation to a NES mode of operation. Example high throughput applications may include multicast and / or broadcast services, which may support streaming video from the cell to one or more UEs, for example. A broadcast transmission may be a data transmission to all or any UEs, while a multicast transmission may be a data transmission of data to UEs that are members of a multicast group (e.g., identified by a multicast group identifier). Therefore,multicast and / or broadcast services (MBS), or UEs receiving MBS, may be (negatively) impacted by serving or camped-on cells that transition from a non-NES mode of operation to a NES mode of operation (or cells that activate NES mode of operation) because those cells may then cease or discontinue transmitting data associated with one or more MBS sessions (multicast sessions and / or broadcast sessions).

[0033] Thus, for example, a UE may receive data associated with a MBS session from a cell. But if that cell activates NES mode of operation (transitions to NES mode of operation), that cell may typically cease or discontinue transmission of that MBS session. A UE may receive from a cell data associated with a MBS session, e.g., while in either idle state (received MBS data from a cell that the idle state UE is camped on) or connected state (receive MBS data from the cell the UE is connected to). However, that cell may, for example, may discontinue transmitting the MBS data when the cell activates NES mode (transitions to NES mode of operation).

[0034] Thus, according to an example embodiment, a UE may initially receive from a first cell (e.g., a source cell) data associated with a first MBS session. The source cell (first cell) may transition to (or activate) the NES mode of operation to conserve energy. According to an example embodiment, the UE may perform a cell switch (either cell reselection or handover to a target (or second) cell. Unfortunately, performing a cell switch to a target cell that is or will soon be in a NES mode of operation, or to a target cell that is not transmitting data associated with the first session of the MBS, will not allow the UE to continue receiving data associated with the first MBS session.

[0035] In addition, in scenarios where UEs interested in MBS services, there are no specified mechanisms defined by 3GPP which determines the behavior of UEs receiving MBS session is served by a cell which is or may transition to NES mode of operation. If the UEs receiving MBS session are in connected state and the serving cell decides to transition to NES mode of operation, it is not clear when the UEs will or should trigger a HO (handover). For broadcast sessions, the serving gNB may even be unaware that a UE is receiving an MBS service.

[0036] Furthermore, if the MBS UEs are in Inactive / Idle state of operation (broadcast can be in IDLE / INACTIVE, multicast can be in INACTIVE) camping in a cell and such cell transitions to NES mode of operation, further guidance for the UEs is needed to be able continue receiving the MBS services, e.g., so that a cell switch may be performed to allow the UE continue receiving the MBS services or session.

[0037] According to an example embodiment, a UE may perform a cell switch to a targetor second (e.g., a neighbor) cell that is transmitting data associated with a MBS session and is in a non-NES mode of operation, before the source cell transitions to the NES mode of operation. Various example techniques are described herein to allow a UE to receive information related to a NES mode of operation for a cell (that is currently transmitting data of a MBS session of interest to the UE) and then perform a cell switch to another cell that is transmitting data associated with the MBS session and is or will be in a non-NES mode of operation while the cell is or enters the NES mode of operation, e.g., in order for the UE to continue receiving data associated with the MBS session.

[0038] Therefore, according to an example embodiment, a UE, which may be (e.g., an idle state UE) camped-on a first cell or (e.g., a UE in connected state) connected to a first cell, may receive from the first cell data associated with a first session of a multicast and / or broadcast services (MBS). The UE may receive from the first cell a message (e.g., a MBS- NES flag) indicating that the MBS will be impacted (e.g., MBS services generally will be impacted) and / or the first session of the MBS will be impacted due to the NES mode of operation for the first cell (e.g., due to a soon or pending transition or activation of the NES mode of operation for the first cell). Thus, this message, e.g., an MBS-NES flag, may indicate that the first cell will be activating the NES mode of operation (e.g., transitioning from non- NES mode to the NES mode of operation). The flag may be a one-bit flag or a multi-bit flag.

[0039] Also, for example, a time period for which the first cell will be in the NES mode of operation or a time of transition to the NES mode of operation may be indicated in the message to indicate a time when the cell will transition to NES mode of operation. Other information or parameters may be included in the message, at least in some cases.

[0040] In an example embodiment, the UE may determine a second cell that is in a non- NES mode of operation and is transmitting the first session of the MBS. The determination may be based on the UE itself receiving information from other cells indicating (present and / or scheduled) NES mode or non-NES mode of operation of the other cells, the other cells including the second cell, or may receive NES mode of operation information from the first cell regarding other cells (at least the second cell). For example, the UE may itself receive system information or other information from one or more neighbor cells or other cells that may indicate, for each cell, a non-NES mode of operation for the respective cell and / or whether the respective cell is transmitting data associated with the first session of the MBS. The UE may receive from the first cell a NES mode of operation indication for one or more other (or neighbor cells) that may indicate a NES mode of operation or a non-NES mode of operation for the other cells (at least the second cell, optionally further cell(s)). Or, the UEmay receive from the first cell a handover configuration for a second cell that is in a non-NES mode of operation and is transmitting the first session of the MBS.

[0041] And, based on the received message (e.g., based on the received MBS-NES flag) indicating the MBS and / or the first session of the MBS will be impacted by the NES mode of operation (e.g., by the transition of the first cell to NES mode of operation) and / or other received information, the UE may perform a cell switch (e.g., a handover or a cell reselection) to the second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation, so that the UE may continue to receive data associated with the first session of the MBS.

[0042] In this manner, the UE may receive a notification (e.g., via the message or the MBS-NES flag or other indication) of a (e.g., pending or scheduled) transition of the first cell (e.g., that is currently serving the UE) to the NES mode of operation, and then the UE may advantageously perform a cell switch (e.g., handover or cell reselection) to a second cell that is transmitting data of the first session of the MBS and is in a non-NES mode of operation.

[0043] FIG. 2 is a flow chart illustrating operation of a UE (or user device) according to an example embodiment. Operation 210 includes receiving, by a user device (e.g., UE) from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS. Operation 220 includes receiving, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell. And, operation 230 includes performing, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0044] With respect to the method of FIG. 2, the cell switch may include either a handover or a cell reselection.

[0045] With respect to the method of FIG. 2, the message may include a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0046] With respect to the method of FIG. 2, the message may include a flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

[0047] With respect to the method of FIG. 2, wherein the first session may be a first broadcast session; wherein the receiving data may include receiving, by the user device that is in an idle or inactive state from the first cell to which the user device is camped-on, dataassociated with the first broadcast session; wherein the method further comprises receiving, by the user device from the first cell, control information indicating a list of neighbor cells that are transmitting the first broadcast session, and a NES mode of operation indication for one or more of the neighbor cells indicating a non-NES mode of operation for the one or more neighbor cells; and wherein the performing the cell switch comprises performing, by the user device, cell reselection to a second cell on the list of neighbor cells that is transmitting the first broadcast session and which is indicated by the control information to be in the non-NES mode of operation.

[0048] With respect to the method of FIG. 2, the NES mode of operation indication may indicate either a NES mode of operation or a non-NES mode of operation for each of the one or more neighbor cells. The indication per cell may be or comprise a flag such as a one-bit flag.

[0049] With respect to the method of FIG. 2, the control information may further include a NES mode of operation indication for additional one or more of the neighbor cells indicating a NES mode of operation for the additional one or more of the neighbor cells, and wherein performing the cell reselection may include: rejecting or omitting, by the user device, performing cell reselection to or camping on a neighbor cell of the list of neighbor cells for which the NES mode of operation indication indicates the NES mode of operation for the rejected or omitted cell.

[0050] With respect to the method of FIG. 2, the control information indicating the list of neighbor cells that are transmitting the first broadcast session, and the NES mode of operation indication for one or more of the neighbor cells may be received by the user device via either a system information block (SIB) information or multicast broadcast services control channel (MCCH) transmitted by the first cell, or both. Similarly, the gNB(s) may broadcast the NES mode of operation indication in the SIB and / or on the MCCH.

[0051] With respect to the method of FIG. 2, the first session is a first broadcast session; the method may further include: if the user device is in an idle or inactive state, establishing a connection to the first cell based on the message; and transmitting, by the user device to the first cell, a MBS interest indication to indicate an interest of the user device in continuing to receive the first broadcast session; and wherein the performing the cell switch may include performing, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first broadcast session and is in a non-NES mode of operation. In this embodiment, upon detecting that the NES mode of operation of the cell will impact the broadcast session, the user device indicates tothe first cell that the user device wants to continue the broadcast session during the NES mode of operation. Through this announcement, the first cell becomes aware of the user device’s intention and is able to switch the user device to a cell that provides the first broadcast session during the NES mode of operation of the first cell. This embodiment does not require the cell to transmit the information on the NES mode of operation of the neighbor cell(s). However, if the cell provides the information on the NES mode of operation of the neighbor cell(s), the user device may measure the neighbor cell(s) and indicate, based on the measurements such as based on a measured signal strength, a preferred neighbor cell for the handover.

[0052] With respect to the method of FIG. 2, wherein the first session is a first multicast session; wherein the method may further include: receiving, by the user device from the camped-on cell, a group paging request indicating a multicast group identifier associated with the first multicast session; and establishing, by the user device based on the group paging request, a connection to the first cell; and wherein the performing the cell switch may include the performing, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first multicast session and is in a non-NES mode of operation. In this embodiment, since the first session is the multicast session, the first cell may be aware of the user devices that receive the first session and is capable of handling the handovers without a separate indication of an intent to continue the service from the user devices.

[0053] FIG. 3 is a flow chart illustrating operation of a gNB (or network node) according to an example embodiment. Operation 310 includes transmitting, by a network node (e.g., gNB) associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS). Operation 320 includes transmitting, by the network node associated with the first cell to at least a first user device (e.g., a first UE), a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0054] With respect to the method of FIG. 3, the cell switch may include either a handover or a cell reselection.

[0055] With respect to the method of FIG. 3, the message may include a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0056] With respect to the method of FIG. 3, the method may further include determining, by the network node, one or more neighbor cells that transmit the first session of the MBS and that are in a non-NES mode of operation; and providing, by the network node to the first user device that is in a connected state, a handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0057] With respect to the method of FIG. 3, the transmitting data may include transmitting, by the network node associated with the first cell that is at least one of a serving cell to one or more connected state user devices or is a camped-on cell for one or more user idle or inactive state user devices, data associated with the first session of the MBS.

[0058] With respect to the method of FIG. 3, the determining may include receiving, by the network node from another network node associated with one or more neighbor cells: an indication that one or more neighbor cells transmit the first session of the MBS; and a NES mode of operation indication for at least one of the one or more neighbor cells indicating a NES mode of operation that will impact the MBS (or the NES mode of operation for each of the neighbor cells may indicate either a NES mode of operation or a non-NES mode of operation for the cell).

[0059] With respect to the method of FIG. 3, the NES mode of operation indication may provide at least one of a current and / or future NES mode of operation indication for the one or more cells, indicating at least one of a current or future NES mode of operation.

[0060] With respect to the method of FIG. 3, the method may further include transmitting, by the network node to one or more user devices including the first user device, control information indicating a list of neighbor cells that are transmitting the first session of the MBS, and a NES mode of operation indication for one or more of the neighbor cells indicating either a NES mode of operation or a non-NES mode of operation for the neighbor cell, to enable the one or more user devices to perform a cell switch to one of the one or more neighbor cells that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0061] With respect to the method of FIG. 3, the control information indicating the list of neighbor cells that are transmitting the first session of the MBS, and the NES mode of operation indication for one or more of the neighbor cells may be transmitted via either a system information block (SIB) information or multicast broadcast services control channel (MCCH), or both.

[0062] With respect to the method of FIG. 3, the method may further includetransmitting, by the network node to another network node, a NES mode of operation indication for the first cell indicating a current or future NES mode of operation that will impact the MBS.

[0063] With respect to the method of FIG. 3, the method may further include establishing a connection between the first cell and the first user device; and receiving, by the network node from the first user device, a MBS interest indication to indicate an interest of the first user device in continuing to receive the first session of the MBS; and wherein the providing the handover configuration comprises providing, by the network node to the first user device based on receiving the MBS interest indication, the handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0064] With respect to the method of FIG. 3, the transmitting data may include transmitting, by the network node associated with the first cell, data associated with a first multicast session of the MBS; and, the method may include: transmitting, by the network node to the first user device that is in an inactive or idle state, a group paging request indicating a multicast group identifier associated with the first multicast session; and establishing a connection between the first cell associated with the network node and the first user device; and wherein the providing a handover configuration may include providing the handover configuration to the first user device via the connection established between the network node and the first user device.

[0065] With respect to the method of FIG. 3, the method may include transmitting, by the network node to at least some of the user devices, a release request and cell reselection flag to cause the at least some of the user devices to release their connection with the first cells associated with the network node and perform cell reselection; wherein the receiving the MBS interest indication comprises receiving, by the network node from one or more remaining user devices that are still connected to the first cell, a MBS interest indication to indicate an interest of the one or more remaining user devices in continuing to receive the first session of the MBS.

[0066] Example Embodiments 1-2:

[0067] Embodiment 1 : The serving cell (or serving gNB providing the serving cell) may know which neighbor cell(s) are providing or transmitting the same MBS session (e.g., the first broadcast session in the examples below of FIG. 4) based on the service areas received from the core network. For a MBS session, a gNB may know the cell(s) that provide the MBS session (transmit data associated with the MBS session) to UEs in RRC Inactive.Whenever, a serving gNB and / or serving or camped-on cell decides to transition to or activate the NES mode of operation or may transition to NES mode of operation in near future depending on the data traffic load, the serving or camped-on gNB sends an indication (NES indication flag) to neighbor cell(s) to inform them of the transition of the cell or serving or camped-on gNB to NES mode of operation. Similarly, the serving gNB (serving one or more UEs) may send the indication (e.g., NES indication flag) to neighbor gNBs (informing the neighboring gNBs of the serving gNBs transition to NES mode), and may also receive the indication from neighbor gNB(s) (e.g., indicating to the serving gNB that the neighbor gNB will be transitioning to NES mode of operation). Also, in some cases, a NES mode may or may not impact MBS sessions, and the serving gNB may also receive a MBS-NES flag from one or more neighbor cells to indicate that MBS services will be impacted by the transition of the neighbor gNB or neighbor cell to NES mode of operation. When MBS is impacted by NES mode, the source (or neighbor) gNB may include a duration time of impact or validity time of impact by which neighbor or receiving gNBs or cells can determine a time period for the NES mode of operation and / or can determine when the neighbor gNB or neighbor cell will transition back to non-NES mode of operation (normal state). When a serving gNB that provides a MBS service receives such indication from neighbor(s), the serving gNB may transmit control information (e.g., as SIB information or MCCH information) to UEs including a list of neighbor cells that are transmitting a particular MBS session(s) and a NES indication (or NES mode of operation indication) for one or more of the neighbor cells indicating either a NES mode or a non-NES mode of operation for the neighbor cell. As per 3 GPP agreement, the NES mode of operation of the cell(s) can impact either cell DTx (discontinuous transmission) / DRx (discontinuous reception) (e.g., a gNB may increase time period between active transmission periods while in NES mode) or beam level impacts (e.g., gNB may reduce the number of beams on which it may transmit reference signals while in NES mode) or paging (gNB may change its paging schedule to sleep longer). Therefore, in addition to the MBS-NES flag (e.g., which may be transmitted by serving gNB to neighbor cells or neighbor gNBs, and / or may be transmitted by serving gNB to UEs) indicating that the MBS service will be impacted by NES mode of operation of the gNB, an additional field (NES impact type) may be provided that specifies a type or kind of NES impact (e.g., indicating one or more of DRx / paging / beam impacted by NES mode) the NES mode can have on the UEs interested to receive MBS session. A serving gNB may transmit this NES impact type (e.g., indicating that one or more of DRx, paging, and / or beam may be impacted by the gNBs transition to NES mode) to neighbor gNBs or neighbor cells and / or may betransmitted to UEs.

[0068] Embodiment 2: In addition to the serving gNB transmitting a NES indication to UEs indicating that the serving gNB will be (or has planned or scheduled) a transition to NES mode of operation, the serving gNB may also transmit to UEs a MBS-NES flag to indicate that MBS services and / or specific MBS sessions will be impacted due to the transition of the serving gNB to NES mode of operation. The MBS-NES flag may be transmitted to UEs via SIB / MCCH information. Based on the information received from the serving gNB, UEs receiving MBS may trigger cell-reselection to camp on another cell that is transmitting the MBS session of interest and is in a non-NES mode of operation. Embodiments 1 and 2 are described in more detail with reference to FIG. 4.

[0069] FIG. 4 is a diagram illustrating an operation of a system according to embodiments 1-2. In embodiments 1 and 2, shown in FIG. 4, UEs in idle or inactive state may perform cell reselection to select serving (or camped-on) gNB 412 to camp on. As shown in FIG. 4, a MBS (multicast and / or broadcast services) UE 410 (a UE that is receiving MBS services, such as a first session of MBS, from gNB 412) may be in an idle or inactive state, in this example. Thus, the (idle or inactive state) MBS UE 410 may be camped-on a first cell provided by camped-on or serving gNB 412.

[0070] At step 1 of FIG. 4, some UEs, such as UE 410, within range of serving gNB 410 are in RRC inactive or idle state and decide to receive a MBS session (e.g., a first broadcast session) from a serving or camped-on gNB 410. At step 2, the serving or camped-on gNB 412 provides the MBS session, e.g., the first broadcast session, e.g., by broadcasting data associated with the first broadcast session. At step 3, UE 410 receives from gNB 412 data associated with the first broadcast session. At step 4, one or more of the neighbor (or other) gNB(s) decide to transition to the NES mode of operation. At step 5, a neighbor gNB(s) 414, which is or will be transitioning to NES mode of operation, transmits a NES mode of operation indication, e.g., a NES indication flag(s), to other gNBs including to gNB 412, to notify gNB 412 of the transition of the neighbor gNB 414 to NES mode of operation. At step 6, the serving (or camped-on) gNB 412 receives NES indication flag(s) from one or more neighbor gNBs 414. Also, the NES indication flags may indicate that a neighbor gNB or neighbor cell is either in a NES mode of operation or a non-NES mode of operation. Also, for example, the NES indication flag received by serving gNB 412 at step 6 may also or alternatively indicate that MBS (or even may indicate that specific sessions of MBS) will be (negatively) impacted by the neighbor gNB 414 transitioning to NES mode of operation. Such an indication that indicates that a gNB transitioning to NES mode of operation willimpact MBS or one or more specific MBS sessions may be referred to as MBS-NES flag.

[0071] At step 7 of FIG. 4, based at least on the information received at step 6, for example, the serving (or camped-on) gNB 412 transmits or broadcasts control information (that may be received by UE 410), e.g., including the NES indication flag for one or more neighbor (or other) cells (e.g., indicating whether the neighbor cell or neighbor gNB is in a NES mode of operation or a non-NES mode of operation) and a list of neighbor cells that are transmitting the first broadcast session. For example, this control information (e.g., including a NES indication flag for each of one or more cells and a list of one or more cells that are transmitting the first broadcast session) may be transmitted or broadcast by the serving or camped-on gNB 412 via system information block (SIB) information and / or via multicast and / or broadcast control channel (MCCH), which may be received by UEs such as UE 410.

[0072] At step 8 of FIG. 4, the serving or camped-on gNB 412 may make a decision to transition to (or activate) the NES mode of operation, e.g., based on an amount of traffic or cell load (for one or more cells provided by gNB 412) being less than a threshold. At step 9 of FIG. 4, the camped-on or serving gNB 412 may transmit to other gNBs / neighbor gNBs 414 and / or to neighbor cells, a NES indication flag that indicates an intent of gNB 412 to transition (e.g., indicating a planned or scheduled transition of gNB 412) to NES mode of operation.

[0073] At step 10 of FIG. 4, according to embodiment 2, the camped-on or serving gNB 412 transmits to the UE(s) 410 a message, which may be or may include a MBS-NES flag, indicating that MBS services and / or a specific MBS session(s) (which may be identified, such as broadcast session 1, by indicating the session ID for the MBS session) may be or will be impacted by the (scheduled or planned) transition of the gNB 412 to the NES mode of operation. For example, the MBS-NES flag may indicate that MBS services, and / or one or more specific (or specifically indicated or identified) broadcast and / or multicast sessions of MBS, will be or may be impacted by the planned or scheduled transition of gNB 412 to NES mode of operation. Providing the MBS-NES flag at step 10 to indicate that MBS services or sessions may or will be impacted by NES mode of operation may result from or may be based on, e.g., a full or partial ceasing or stopping of transmission of data (including MBS data) by gNB 412 or a scheduled reduced or intermittent transmission of data by gNB 412 while gNB 412 is in NES mode of operation, as examples, which will prevent the UE 410 from continuing to receive the MBS session or broadcast session from gNB 412 while in NES mode of operation.

[0074] At step 11, the UE 410 receives the MBS-NES flag indicating that MBS services(or MBS sessions) and / or indicating that the first broadcast session (that is being received by the UE 410 from gNB 412) will be or may be impacted (e.g., negatively impacted, such as stopped, ceased or slowed down the transmission of data associated with the MBS or broadcast session) due to a transition of the camped-on or serving gNB 412 to the NES mode of operation. Based on this received MBS-NES flag, the UE 410 determines that MBS service and / or the first broadcast session will be impacted due to the transition of the gNB 412 to NES mode of operation.

[0075] At step 12 of FIG. 4, the UE 410 initiates cell reselection to search for the best frequencies and / or cells to camp on. At step 13, while measuring signals or frequencies to determine the best frequency or cell to camp on, the UE 410 may select a cell that is: 1) transmitting the first broadcast session, and 2) in a non-NES mode of operation, e.g., based on the control information received from gNB 412 at step 7 of FIG. 4, for example, in order to continue receiving the first broadcast session. Also, for example, at step 13 of FIG. 4, the UE 410 may reject or omit performing cell reselection to or camping on a neighbor cell (or cell provided by a gNB) for which the control information received at step 7 indicates that the neighbor cell or neighbor gNB is in (or is planned to be in) a NES mode of operation and / or is not transmitting the first broadcast session or other MBS session of interest.

[0076] Example Embodiment 3 :

[0077] Embodiment 3 is a variant of embodiment 2. In embodiment 3, the serving gNB instructs the UE to establish a connection to the camped-on cell. After establishing a connection to the serving cell / camped on cell (or if the UE was already in a connected state), the UE may transmit a MBS interest indication (Mil) to the serving cell / serving gNB, to indicate the UE’s interest in continuing to receive data associated with an indicated MBS session. As part of the Mil, UE may identify the MBS session of interest by providing a MBS session identifier, or a multicast group identifier (e.g., TMGIs of multicast group sessions of interest, in the case of multicast session(s)). The advantage of having the UE connect to the serving (or camped-on) cell is that, rather than the UE performing cell reselection by itself, the serving gNB can now (after UE has established a connection) assist or facilitate (e.g., by providing one or more handover configurations to the UE) with handover of the UE to a cell that provides the MBS session of interest and is in a non-NES mode of operation. Embodiment 3 is described hereinbelow with reference to FIG. 5.

[0078] FIG. 5 is a diagram illustrating example embodiment 3. At step 1, a MBS UE 410 (a UE that may be receiving a MBS session from a first cell (cell 1) of a serving gNB 412) may be in an idle, inactive or connected state. Thus, for example, the UE 410 may either becamped-on the first cell provided by gNB 412 or may be connected to the first cell provided by gNB 412, in order to receive data associated with a first broadcast session. At step 2, the serving gNB provides the first MBS broadcast session, e.g., by transmitting data associated with the first MBS broadcast session. At step 3, the UE 410 receives data associated with the first broadcast session from the serving gNB 412. At step 4, the serving gNB 412 decides to transition (or schedule a transition) to the NES mode of operation, e.g., based on cell load or traffic load for one or more cells being less than a threshold. At step 5, per embodiment 2, the serving gNB 412 transmits a MBS-NES flag to UEs (including UE 410) to indicate that MBS and / or specific MBS sessions may or will be (adversely or negatively) impacted due to the transition of the serving gNB 412 to NES mode of operation. At step 6, based on received MBS-NES flag, UE 410 determines that MBS services, e.g., the first broadcast session, will be impacted due to NES mode of operation for gNB 412 (or due to transition of gNB 412 to NES mode).

[0079] Steps 7-10 of FIG. 5 are performed if the UE 410 is initially in an idle or inactive state (scenarios 0-1 of embodiment 3). At step 7, the UE 410 establishes a connection to the camped-on cell (cell camped-on by the UE 410) provided by the serving gNB 412, based on UE 410 determining the that first broadcast session will be impacted by the NES mode of operation. At step 8, as part of the UE establishing or re-establishing or resuming a connection to the first cell provided by gNB 412, the UE may transmit a RRC Setup Request, or a RRC Reestablishment Request or a RRC Resume Request to the gNB 412 upon which the gNB 412 transmits to the UE 410 a RRC Setup or a RRC Reestablishment or a RRC Resume, to return the UE to a connected state with respect to the first cell of the gNB 412. At step 10, the UE (which is now connected to first cell or gNB 412) creates a MBS interest indication, which may indicate the MBS session ID or multicast group ID.

[0080] Step 11 of FIG. 5 is performed if the UE 410 was already in a connected state (scenario 2 of embodiment 3). At step 11, UE 410 creates a MBS interest indication, which may indicate the MBS session ID or multicast group ID.

[0081] At step 12 of FIG. 5, the UE 410 transmits to gNB 412 the MBS interest indication (Mil), e.g., which may include the session ID and / or groupcast ID (identifier) of the MBS sessions of interest. This informs the serving gNB 412 about the particular MBS session(s) or services that the UE 410 is interested in continuing to receive, and also informs the gNB 412 about the location of the UE (e.g., such as which cell the UE is connected to). This information may allow the serving gNB 412 to configure prepared cells for UE handover more efficiently, which may include the gNB determining one or more cells thattransmit the MBS session of interest and are provided by gNBs that are in a non-NES mode of operation. The gNB 412 may then send a handover configuration for one or more of these cells to the UE 410 before the serving gNB 412 transitions to NES mode. At step 13, the serving gNB 412 performs a handover of the UE 410 to one of these cells where the UE can continue to receive the MBS session of interest, e.g., the first broadcast session.

[0082] Example Embodiment 4:

[0083] The example embodiment 4 covers or includes operation for multicast reception while a UE is in an inactive (RRC Inactive) state, rather than for receiving a broadcast session as covered above in some of the earlier embodiments. Embodiment 4 (including 4a and 4b) includes an operation that is similar to operation of embodiment 3, but is for multicast group or multicast sessions. In 4a, the UE receives the MBS-NES flag to indicate that MBS sessions (including the multicast session) will be impacted by serving gNB transition to NES mode. In 4b, the serving gNB pages, or perform a group paging request to the multicast group identifier (or TMGI) associated with or identifying the multicast session that the UE 410 is receiving, which causes the UE 410 to establish a connection to the first cell or serving gNB 412. Embodiment 4 is described with reference to FIG. 6.

[0084] FIG. 6 is a diagram illustrating example embodiment 4. At step 1, UE 410 is in an inactive state and decides to receive a first MBS multicast session (or multicast session 1) from serving gNB 412. At step 2, the serving gNB 412 initiates the first MBS multicast session, e.g., by transmitting data associated with the first MBS multicast session. At step 3, the UE 410 (or UEs within the serving gNB) begin receiving data associated with the first MBS multicast session. At step 4, the serving cell or serving gNB 412 that provides the serving cell or first cell decides or makes a determination to transition to a NES mode of operation. Steps 5-6 are for embodiment 4a. At step 5, the serving gNB 412 transmits or broadcasts the MBS-NES flag to indicate that MBS sessions and / or specific MBS sessions will or may be impacted by the NES mode of operation that is planned or scheduled for the serving gNB 412. At step 6, the UE 410 receives the MBS-NES flag, and determines that the first MBS multicast session that is being received by UE 410 will be impacted by the transition of the serving gNB 412 to NES mode. Steps 7-8 are for embodiment 4b. At step 7, the gNB 412 pages or transmits a group paging request addressed to the multicast group ID (e.g., TMGI) for the first MBS multicast session. At step 8, UE 410 receives the group paging request for the first MBS multicast group session. At steps 9-10, in response to receiving the paging request or the MBS-NES flag to indicate that MBS sessions and / or specific MBS sessions will or may be impacted by the NES mode of operation that is plannedor scheduled for the serving gNB 412, the UE 410 performs cell reconnection to the serving cell provided by the serving gNB 412 and UE 410 is now in a connected state at step 11. At step 12, with the assistance of serving gNB 412 (e.g., based on a handover configuration provided by serving gNB to UE 410), the serving gNB 412 performs or assists the UE in performing a handover of UE 410 to a cell that provides the first MBS multicast session (transmits data associated with the first MBS multicast session) and the gNB associated with such cell is in a non-NES mode of operation.

[0085] Example Embodiment 5:

[0086] Example embodiment 5 covers a situation where UEs in a connected state are receiving a MBS broadcast session. The serving gNB, which will be transitioning to NES mode, may first move or send some or all of its UEs in a connected state (RRC Connected) to inactive state (RRC Inactive) and then may trigger or cause cell reselection for these inactive UEs. The purpose of this action may be to allow the NES mode (e.g., to be performed without impacting these UEs). At the same time, the serving gNB may opportunistically reduce the number of UEs that will require the handover in order to continue reception of the MBS broadcast session. The serving gNB may also transmit the MBS-NES flag, which is received by the remaining UEs still in connected state. The remaining UEs that are still in a connected state may perform handover to another cell to continue receiving the MBS broadcast session. Example embodiment 5 is described in more detail with reference to FIG. 7.

[0087] FIG. 7 is a diagram illustrating example embodiment 5. At steps 1-3 of FIG. 7, a UE in a connected state receives data associated with a first MBS broadcast session from a first cell of serving gNB 412. At step 4, serving gNB 412 makes a determination to transition to NES mode of operation, e.g., based on cell load that is less than a threshold. At step 5 of embodiment 5, serving gNB 412 decides (or determines) to send (or cause) some of its connected UEs to enter an inactive state and perform cell reselection. At step 6, the serving gNB 412 transmits a RRC Release with suspend configuration along with cell reselection flag to some of the UEs that are connected to the cell(s) provided by the serving gNB 412. The UEs sent to the inactive state may be selected according to various criteria. For example, the selected UEs may exclude any UE that transmits or receives time-critical data, e.g. has an ultra-reliable low latency (URLLC) connection. On the other hand, any UE not having such a low-latency or time-critical connection may be selected. At step 7, this RRC Release with suspend configuration with cell reselection flag is received by one or more of these UEs including UE 410, which causes or triggers these UEs (including UE 410) to transition toinactive state and perform cell reselection to camp on another cell within the RAN notification area. The serving gNB 412 may include in the RRC Release the NES indication flag for one or more neighbor (or other) cells (e.g., indicating whether the neighbor cell or neighbor gNB is in a NES mode of operation or a non-NES mode of operation) and a list of neighbor cells that are transmitting the first MBS broadcast session. Based on the NES indication flag for one or more neighbor (or other) cells, these UEs which transitioned to inactive state may reselect a cell that is transmitting the first MBS broadcast session and is in a non-NES mode of operation. At step 8, the serving gNB 412 may evaluate or determine if gNB 412 transitioning to NES mode will impact the first MBS broadcast session that the gNB 412 is transmitting. At steps 9-10, after determining the NES mode will impact the MBS broadcast session, the gNB 412 transmits to UE 410 the MBS-NES flag, and UE 410 determines that the first MBS broadcast session will be impacted by NES mode. For example, MBS-NES flag set to 1 indicates that MBS or MBS session will be impacted, and is set to 0 to indicate that MBS or a MBS session is not impacted by NES mode. At steps 11- 12, the UE 410 creates and sends to gNB 412 a MBS interest indication to indicate the UE’s interest in continuing to receive the first MBS broadcast session. At step 13, the serving gNB 412 performs or initiates a handover of the UE 410 (e.g., by providing a handover configuration to the UE 410) to another cell or neighbor cell that is transmitting the first MBS broadcast session and is in a non-NES mode.

[0088] Example 1. 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, by a user device from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receive, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and perform, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0089] Example 2. The apparatus of example 1, wherein the cell switch comprises either a handover or a cell reselection.

[0090] Example 3. The apparatus of any of examples 1-2, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0091] Example 4. The apparatus of any of examples 1-3, wherein the message comprisesa flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

[0092] Example 5. The apparatus of any of examples 1-4: wherein the first session is a first broadcast session; wherein the apparatus caused to receive data comprises the apparatus caused to receive, by the user device that is in an idle or inactive state from the first cell to which the user device is camped-on, data associated with the first broadcast session; wherein the apparatus is further caused to receive, by the user device from the first cell, control information indicating a list of neighbor cells that are transmitting the first broadcast session, and a NES mode of operation indication for one or more of the neighbor cells indicating a non-NES mode of operation for the one or more neighbor cells; wherein the apparatus caused to perform the cell switch comprises the apparatus caused to perform, by the user device, cell reselection to a second cell on the list of neighbor cells that is transmitting the first broadcast session and which is indicated by the control information to be in the non-NES mode of operation.

[0093] Example 6. The apparatus of example 5 wherein the NES mode of operation indication indicates either a NES mode of operation or a non-NES mode of operation for each of the one or more neighbor cells.

[0094] Example 7. The apparatus of example 5, wherein the control information further comprises NES mode of operation indication for additional one or more of the neighbor cells indicating a NES mode of operation for the additional one or more of the neighbor cells, and wherein the apparatus caused to perform the cell reselection comprises the apparatus caused to: reject or omit, by the user device, performing cell reselection to or camping on a neighbor cell of the list of neighbor cells for which the NES mode of operation indication indicates the NES mode of operation for the rejected or omitted cell.

[0095] Example 8. The apparatus of any of examples 5-7, wherein the control information indicating the list of neighbor cells that are transmitting the first broadcast session, and the NES mode of operation indication for one or more of the neighbor cells is received by the user device via either a system information block (SIB) information or multicast broadcast services control channel (MCCH) transmitted by the first cell.

[0096] Example 9. The apparatus of example 1 : wherein the first session is a first broadcast session; wherein the apparatus is further caused to: if the user device is in an idle or inactive state, establish a connection to the first cell based on the message; and transmit, by the user device to the first cell, a MBS interest indication to indicate an interest of the user device in continuing to receive the first broadcast session; and wherein the apparatus causedto perform the cell switch comprises the apparatus caused to perform, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first broadcast session and is in a non-NES mode of operation.

[0097] Example 10. The apparatus of example 1 : wherein the first session is a first multicast session; wherein the apparatus is further caused to: receive, by the user device from the camped-on cell, a group paging request indicating a multicast group identifier associated with the first multicast session; establish, by the user device based on the group paging request, a connection to the first cell; and wherein the apparatus caused to perform the cell switch comprises the apparatus caused to perform, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first multicast session and is in a non-NES mode of operation.

[0098] Example 11. A method comprising: receiving, by a user device from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receiving, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and performing, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0099] Example 12. The method of example 11, wherein the cell switch comprises either a handover or a cell reselection.

[0100] Example 13. The method of any of examples 11-12, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0101] Example 14. The method of any of examples 11-13, wherein the message comprises a flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

[0102] Example 15. The method of any of examples 11-14: wherein the first session is a first broadcast session; wherein the receiving data comprises receiving, by the user device that is in an idle or inactive state from the first cell to which the user device is camped-on, data associated with the first broadcast session; wherein the method further comprises receiving, by the user device from the first cell, control information indicating a list of neighbor cells that are transmitting the first broadcast session, and a NES mode of operationindication for one or more of the neighbor cells indicating a non-NES mode of operation for the one or more neighbor cells; and wherein the performing the cell switch comprises performing, by the user device, cell reselection to a second cell on the list of neighbor cells that is transmitting the first broadcast session and which is indicated by the control information to be in the non-NES mode of operation.

[0103] Example 16. The method of example 15 wherein the NES mode of operation indication indicates either a NES mode of operation or a non-NES mode of operation for each of the one or more neighbor cells.

[0104] Example 17. The method of example 15, wherein the control information further comprises NES mode of operation indication for additional one or more of the neighbor cells indicating a NES mode of operation for the additional one or more of the neighbor cells, and wherein performing the cell reselection comprises: rejecting or omitting, by the user device, performing cell reselection to or camping on a neighbor cell of the list of neighbor cells for which the NES mode of operation indication indicates the NES mode of operation for the rejected or omitted cell.

[0105] Example 18. The method of any of examples 15-17, wherein the control information indicating the list of neighbor cells that are transmitting the first broadcast session, and the NES mode of operation indication for one or more of the neighbor cells is received by the user device via either a system information block (SIB) information or multicast broadcast services control channel (MCCH) transmitted by the first cell.

[0106] Example 19. The method of example 11 : wherein the first session is a first broadcast session; the method further comprising: if the user device is in an idle or inactive state, establishing a connection to the first cell based on the message; and transmitting, by the user device to the first cell, a MBS interest indication to indicate an interest of the user device in continuing to receive the first broadcast session; and wherein the performing the cell switch comprises performing, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first broadcast session and is in a non-NES mode of operation.

[0107] Example 20. The method of example 11 : wherein the first session is a first multicast session; wherein the method further comprises: receiving, by the user device from the camped-on cell, a group paging request indicating a multicast group identifier associated with the first multicast session; and establishing, by the user device based on the group paging request, a connection to the first cell; and wherein the performing the cell switch comprises the performing, by the user device based on a handover configuration received bythe user device from the first cell, a handover to the second cell that is transmitting the first multicast session and is in a non-NES mode of operation.

[0108] Example 21. 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: transmit, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmit, by the network node associated with the first cell to at least a first user device, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energysaving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0109] Example 22. The apparatus of example 21, wherein the cell switch comprises either a handover or a cell reselection.

[0110] Example 23. The apparatus of any of examples 21-22, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0111] Example 24. The apparatus of any of examples 21-23, wherein the apparatus is further caused to: determine, by the network node, one or more neighbor cells that transmit the first session of the MBS and that are in a non-NES mode of operation; provide, by the network node to the first user device that is in a connected state, a handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0112] Example 25. The apparatus of any of examples 21-24, wherein the apparatus caused to transmit data comprises the apparatus caused to: transmit, by the network node associated with the first cell that is at least one of a serving cell to one or more connected state user devices or is a camped-on cell for one or more user idle or inactive state user devices, data associated with the first session of the MBS.

[0113] Example 26. The apparatus of any of examples 24-25, wherein the apparatus caused to determine comprises the apparatus caused to: receive, by the network node from another network node associated with one or more neighbor cells: an indication that one or more neighbor cells transmit the first session of the MBS; and a NES mode of operation indication for at least one of the one or more neighbor cells indicating a NES mode of operation that will impact the MBS.

[0114] Example 27. The apparatus of example 26, wherein the NES mode of operationindication provides at least one of a current and / or future NES mode of operation indication for the one or more cells, indicating at least one of a current or future NES mode of operation.

[0115] Example 28. The apparatus of any of examples 21-27, wherein the apparatus is further caused to: transmit, by the network node to one or more user devices including the first user device, control information indicating a list of neighbor cells that are transmitting the first session of the MBS, and a NES mode of operation indication for one or more of the neighbor cells indicating either a NES mode of operation or a non-NES mode of operation for the neighbor cell, to enable the one or more user devices to perform a cell switch to one of the one or more neighbor cells that is transmitting the first session of the MBS and is in a non- NES mode of operation.

[0116] Example 29. The apparatus of example 28, wherein the control information indicating the list of neighbor cells that are transmitting the first session of the MBS, and the NES mode of operation indication for one or more of the neighbor cells is transmitted via either a system information block (SIB) information or multicast broadcast services control channel (MCCH).

[0117] Example 30. The apparatus of any of examples 21-29, wherein the apparatus is further caused to: transmit, by the network node to another network node, a NES mode of operation indication for the first cell indicating a current or future NES mode of operation that will impact the MBS.

[0118] Example 31. The apparatus of example 24, wherein the apparatus is further caused to: establish a connection between the first cell and the first user device; receive, by the network node from the first user device, a MBS interest indication to indicate an interest of the first user device in continuing to receive the first session of the MBS; and wherein the apparatus caused to provide the handover configuration comprises the apparatus configured to provide, by the network node to the first user device based on receiving the MBS interest indication, the handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0119] Example 32. The apparatus of example 24: wherein the apparatus is caused to transmit data comprises the apparatus caused to transmit, by the network node associated with the first cell, data associated with a first multicast session of the MBS; wherein the apparatus is caused to: transmit, by the network node to the first user device that is in an inactive or idle state, a group paging request indicating a multicast group identifier associated with the first multicast session; and, establish a connection between the first cell associated with the network node and the first user device; and wherein the apparatus caused to providea handover configuration comprises the apparatus caused to provide the handover configuration to the first user device via the connection established between the network node and the first user device.

[0120] Example 33. The apparatus of example 31, wherein the apparatus is caused to: transmit, by the network node to at least some of the user devices, a release request and cell reselection flag to cause the at least some of the user devices to release their connection with the first cells associated with the network node and perform cell reselection; wherein the apparatus caused to receive the MBS interest indication comprises the apparatus caused to receive, by the network node from one or more remaining user devices that are still connected to the first cell, a MBS interest indication to indicate an interest of the one or more remaining user devices in continuing to receive the first session of the MBS.

[0121] Example 34. A method comprising: transmitting, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmitting, by the network node associated with the first cell to at least a first user device, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0122] Example 35. The method of example 34, wherein the cell switch comprises either a handover or a cell reselection.

[0123] Example 36. The method of any of examples 34-35, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0124] Example 37. The method of any of examples 34-36, further comprising: determining, by the network node, one or more neighbor cells that transmit the first session of the MBS and that are in a non-NES mode of operation; and providing, by the network node to the first user device that is in a connected state, a handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0125] Example 38. The method of any of examples 34-37, wherein the transmitting data comprises: transmitting, by the network node associated with the first cell that is at least one of a serving cell to one or more connected state user devices or is a camped-on cell for one or more user idle or inactive state user devices, data associated with the first session of the MBS.

[0126] Example 39. The method of any of examples 37-38, wherein the determining comprises: receiving, by the network node from another network node associated with one or more neighbor cells: an indication that one or more neighbor cells transmit the first session of the MBS; and a NES mode of operation indication for at least one of the one or more neighbor cells indicating a NES mode of operation that will impact the MBS.

[0127] Example 40. The apparatus of example 39, wherein the NES mode of operation indication provides at least one of a current and / or future NES mode of operation indication for the one or more cells, indicating at least one of a current or future NES mode of operation.

[0128] Example 41. The method of any of examples 34-40, further comprising: transmitting, by the network node to one or more user devices including the first user device, control information indicating a list of neighbor cells that are transmitting the first session of the MBS, and a NES mode of operation indication for one or more of the neighbor cells indicating either a NES mode of operation or a non-NES mode of operation for the neighbor cell, to enable the one or more user devices to perform a cell switch to one of the one or more neighbor cells that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0129] Example 42. The method of example 41, wherein the control information indicating the list of neighbor cells that are transmitting the first session of the MBS, and the NES mode of operation indication for one or more of the neighbor cells is transmitted via either a system information block (SIB) information or multicast broadcast services control channel (MCCH).

[0130] Example 43. The method of any of examples 34-42, further comprising: transmitting, by the network node to another network node, a NES mode of operation indication for the first cell indicating a current or future NES mode of operation that will impact the MBS.

[0131] Example 44. The method of example 37, further comprising: establishing a connection between the first cell and the first user device; and receiving, by the network node from the first user device, a MBS interest indication to indicate an interest of the first user device in continuing to receive the first session of the MBS; and wherein the providing the handover configuration comprises providing, by the network node to the first user device based on receiving the MBS interest indication, the handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0132] Example 45. The method of example 37: wherein the transmitting data comprisestransmitting, by the network node associated with the first cell, data associated with a first multicast session of the MBS; the method comprising: transmitting, by the network node to the first user device that is in an inactive or idle state, a group paging request indicating a multicast group identifier associated with the first multicast session; and establishing a connection between the first cell associated with the network node and the first user device; and wherein the providing a handover configuration comprises the providing the handover configuration to the first user device via the connection established between the network node and the first user device.

[0133] Example 46. The method of example 44, comprising: transmitting, by the network node to at least some of the user devices, a release request and cell reselection flag to cause the at least some of the user devices to release their connection with the first cells associated with the network node and perform cell reselection; wherein the receiving the MBS interest indication comprises receiving, by the network node from one or more remaining user devices that are still connected to the first cell, a MBS interest indication to indicate an interest of the one or more remaining user devices in continuing to receive the first session of the MBS.

[0134] Example 47. 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, by a user device in a connected state from a first cell that is a serving cell, data associated with a first session of a multicast and / or broadcast services, MBS; receive, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and perform, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0135] Example 48. The apparatus of example 47, wherein the cell switch comprises a handover.

[0136] Example 49. The apparatus of any of examples 47-48, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0137] Example 50. The apparatus of any of examples 47-49, wherein the message comprises a flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

[0138] Example 51. The apparatus of any of examples 47-50, further configured to: receive, from the first cell, a release request comprising a cell reselection flag; based on the received release request, release a connection with the serving cell; and based on the cell reselection flag, continue the first session in the second cell in an idle state, inactive state, or connected state.

[0139] Example 52. The apparatus of any of examples 47-51, further configured to: based on the received message, transmit to the first cell a message indicating that the user device wants to continue the first session; based on the transmitted message, receive a handover message from the first cell; and based on the received handover message, perform a handover to the second cell and continue the first session in the second cell.

[0140] Example 53. The apparatus of example 52, configured to transmit the message together with a measurement report based on measuring the second cell.

[0141] Example 54. A method comprising: receiving, by a user device in a connected state from a first cell that is a serving cell, data associated with a first session of a multicast and / or broadcast services, MBS; receiving, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and perform, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0142] Example 55. The method of example 54, wherein the cell switch comprises a handover.

[0143] Example 56. The method of any of examples 54-55, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0144] Example 57. The method of any of examples 54-56, wherein the message comprises a flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

[0145] Example 58. The method of any of examples 54-57, further comprising by the user device: receiving, from the first cell, a release request comprising a cell reselection flag; based on the received release request, releasing a connection with the serving cell; and based on the cell reselection flag, continuing the first session in the second cell in an idle state, inactive state, or connected state.

[0146] Example 59. The method of any of examples 54-58, further comprising by theuser device: based on the received message, transmitting to the first cell a message indicating that the user device wants to continue the first session; based on the transmitted message, receiving a handover message from the first cell; and based on the received handover message, perform a handover to the second cell and continue the first session in the second cell.

[0147] Example 60. The method of example 59, wherein the user device measures the second cell and transmits the message together with a measurement report based on said measuring the second cell.

[0148] Example 61. 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: transmit, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmit, by the network node associated with the first cell to at least a first user device that is in a connected state, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0149] Example 62. The apparatus of example 61, wherein the cell switch comprises a handover.

[0150] Example 63. The apparatus of any of examples 61-62, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0151] Example 64. The apparatus of any of examples 61-63, wherein the apparatus is further caused to: determine, by the network node, one or more neighbor cells that transmit the first session of the MBS and that are in a non-NES mode of operation; provide, by the network node to the first user device that is in a connected state, a handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0152] Example 65. The apparatus of any of examples 61-64, wherein the apparatus is caused to: transmit, by the network node to the first user device, a release request and cell reselection flag to cause the first user device to release its connection with the first cell and perform cell reselection.

[0153] Example 66. The apparatus of any of examples 61-64, wherein the apparatus is caused to: based on the transmitted message, receive from the first user device a messageindicating that the first user device wants to continue the first session; based on the received message, transmit to the first user device a handover message to cause the first user device to perform a handover to the second cell and continue the first session in the second cell.

[0154] Example 67. The apparatus of claim 66, configured to: receive the message together with a measurement report based on measuring the second cell; and select the second cell as a target cell for the handover based on the received measurement report.

[0155] Example 68. A method comprising: transmitting, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmitting, by the network node associated with the first cell to at least a first user device that is in a connected state, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0156] Example 69. The method of example 68, wherein the cell switch comprises a handover.

[0157] Example 70. The method of any of examples 68-69, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0158] Example 71. The method of any of examples 68-70, further comprising by the network node: determining one or more neighbor cells that transmit the first session of the MBS and that are in a non-NES mode of operation; providing, to the first user device that is in a connected state, a handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0159] Example 72. The method of any of examples 68-71, further comprising: transmitting, by the network node to the first user device, a release request and cell reselection flag to cause the first user device to release its connection with the first cell and perform cell reselection.

[0160] Example 73. The method of any of examples 68-72, further comprising by the network node: based on the transmitted message, receiving from the first user device a message indicating that the first user device wants to continue the first session; based on the received message, transmitting to the first user device a handover message to cause the first user device to perform a handover to the second cell and continue the first session in the second cell.

[0161] Example 74. The method of example 73, further comprising by the network node: receiving the message together with a measurement report based on measuring the second cell; and selecting the second cell as a target cell for the handover based on the received measurement report.

[0162] Example 75. 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, by a user device from a first cell that is a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receive, by the user device in an inactive state or idle state from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and perform, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0163] Example 76. The apparatus of example 75, wherein the cell switch comprises a cell reselection.

[0164] Example 77. The apparatus of any of examples 75-76, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0165] Example 78. The apparatus of any of examples 75-77, wherein the message comprises a flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

[0166] Example 79. The apparatus of any of examples 75-78: wherein the first session is a first broadcast session; wherein the apparatus caused to receive data comprises the apparatus caused to receive, by the user device that is in the idle or inactive state from the first cell to which the user device is camped-on, data associated with the first broadcast session; wherein the apparatus is further caused to receive, by the user device from the first cell, control information indicating a list of neighbor cells that are transmitting the first broadcast session, and a NES mode of operation indication for one or more of the neighbor cells indicating a non-NES mode of operation for the one or more neighbor cells; wherein the apparatus caused to perform the cell switch comprises the apparatus caused to perform, by the user device, cell reselection to a second cell on the list of neighbor cells that is transmitting the first broadcast session and which is indicated by the control information to be in the non-NES mode of operation.

[0167] Example 80. The apparatus of example 79, wherein the control information further comprises NES mode of operation indication for additional one or more of the neighbor cells indicating a NES mode of operation for the additional one or more of the neighbor cells, and wherein the apparatus caused to perform the cell reselection comprises the apparatus caused to: reject or omit, by the user device, performing cell reselection to or camping on a neighbor cell of the list of neighbor cells for which the NES mode of operation indication indicates the NES mode of operation for the rejected or omitted cell.

[0168] Example 81. The apparatus of any of example 75-79, configured to receive the message via either a system information block (SIB) information or multicast broadcast services control channel (MCCH) transmitted by the first cell.

[0169] Example 82. The apparatus of example 75: wherein the first session is a first broadcast session; wherein the apparatus is further caused to: establish a connection to the first cell based on the message; and transmit, by the user device to the first cell, a MBS interest indication to indicate an interest of the user device in continuing to receive the first broadcast session; and wherein the apparatus caused to perform the cell switch comprises the apparatus caused to perform, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first broadcast session and is in a non-NES mode of operation and continue the first session in the second cell.

[0170] Example 83. The apparatus of examples 75: wherein the first session is a first multicast session; wherein the apparatus is further caused to: receive, by the user device from the camped-on cell, a group paging request indicating a multicast group identifier associated with the first multicast session; establish, by the user device based on the group paging request, a connection to the first cell; and wherein the apparatus caused to perform the cell switch comprises the apparatus caused to perform, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first multicast session and is in a non-NES mode of operation.

[0171] Example 84. A method comprising: receiving, by a user device from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receiving, by the user device in an idle state or an inactive state from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and performing, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode ofoperation.

[0172] Example 85. The method example 84, wherein the cell switch comprises a cell reselection.

[0173] Example 86. The method of any of examples 84-85, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0174] Example 87. The method of any of examples 84-86, wherein the message comprises a flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

[0175] Example 88. The method of any of examples 84-87: wherein the first session is a first broadcast session; wherein the receiving data comprises receiving, by the user device in the idle or inactive state from the first cell to which the user device is camped-on, data associated with the first broadcast session; wherein the method further comprises receiving, by the user device from the first cell, control information indicating a list of neighbor cells that are transmitting the first broadcast session, and a NES mode of operation indication for one or more of the neighbor cells indicating a non-NES mode of operation for the one or more neighbor cells; and wherein the performing the cell switch comprises performing, by the user device, cell reselection to a second cell on the list of neighbor cells that is transmitting the first broadcast session and which is indicated by the control information to be in the non-NES mode of operation.

[0176] Example 89. The method of example 88, wherein the control information further comprises NES mode of operation indication for additional one or more of the neighbor cells indicating a NES mode of operation for the additional one or more of the neighbor cells, and wherein performing the cell reselection comprises: rejecting or omitting, by the user device, performing cell reselection to or camping on a neighbor cell of the list of neighbor cells for which the NES mode of operation indication indicates the NES mode of operation for the rejected or omitted cell.

[0177] Example 90. The method of any of examples 84-89, wherein the message is received by the user device via either a system information block (SIB) information or multicast broadcast services control channel (MCCH) transmitted by the first cell.

[0178] Example 91. The method of example 84: wherein the first session is a first broadcast session; the method further comprising: establishing a connection to the first cell based on the message; and transmitting, by the user device to the first cell, a MBS interestindication to indicate an interest of the user device in continuing to receive the first broadcast session; and wherein the performing the cell switch comprises performing, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first broadcast session and is in a non-NES mode of operation and continuing the first session in the second cell.

[0179] Example 92. The method of example 84: wherein the first session is a first multicast session; wherein the method further comprises: receiving, by the user device from the camped-on cell, a group paging request indicating a multicast group identifier associated with the first multicast session; and establishing, by the user device based on the group paging request, a connection to the first cell; and wherein the performing the cell switch comprises the performing, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first multicast session and is in a non-NES mode of operation.

[0180] Example 93. 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: transmit, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmit, by the network node associated with the first cell to at least a first user device that is in an inactive state or idle state, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0181] Example 94. The apparatus of example 93, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0182] Example 95. The apparatus of any of examples 93-94, wherein the apparatus caused to transmit data comprises the apparatus caused to: transmit, by the network node associated with the first cell that is a camped-on cell for one or more user idle or inactive state user devices, data associated with the first session of the MBS.

[0183] Example 96. The apparatus of any of examples 93-95, configured to transmit the message via either a system information block (SIB) information or multicast broadcast services control channel (MCCH).

[0184] Example 97. The apparatus of any of exapmles 93-96, wherein the apparatus is further caused to: establish a connection between the first cell and the first user device;receive, by the network node from the first user device, a MBS interest indication to indicate an interest of the first user device in continuing to receive the first session of the MBS; and wherein the apparatus caused to provide the handover configuration comprises the apparatus configured to provide, by the network node to the first user device based on receiving the MBS interest indication, the handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0185] Example 98. The apparatus of any of examples 93-97: wherein the apparatus is caused to transmit data comprises the apparatus caused to transmit, by the network node associated with the first cell, data associated with a first multicast session of the MBS; wherein the apparatus is caused to: transmit, by the network node to the first user device that is in the inactive or idle state, a group paging request indicating a multicast group identifier associated with the first multicast session; and establish a connection between the first cell associated with the network node and the first user device; and wherein the apparatus caused to provide a handover configuration comprises the apparatus caused to provide the handover configuration to the first user device via the connection established between the network node and the first user device.

[0186] Example 99. A method comprising: transmitting, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmitting, by the network node associated with the first cell to at least a first user device that is in a inactive state or in an idle state, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

[0187] Example 100. The method of example 99, wherein the message comprises a MBS- NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

[0188] Example 101. The method of any of examples 99-100, wherein said data transmission comprises transmitting, by the network node associated with the first cell that is a camped-on cell for one or more user idle or inactive state user devices, data associated with the first session of the MBS.

[0189] Example 102. The method of any of examples 99-101, wherein the network node transmits the message via either a system information block (SIB) information or multicastbroadcast services control channel (MCCH).

[0190] Example 103. The method of any of examples 99-102, further comprising: establishing, by the network node, a connection between the first cell and the first user device; receiving, by the network node from the first user device, a MBS interest indication to indicate an interest of the first user device in continuing to receive the first session of the MBS; and providing, by the network node to the first user device based on receiving the MBS interest indication, the handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

[0191] Example 104. The method of any of examples 99-103, further comprising: transmitting, by the network node associated with the first cell, data associated with a first multicast session of the MBS; transmitting, by the network node to the first user device that is in the inactive or idle state, a group paging request indicating a multicast group identifier associated with the first multicast session; establishing, by the network node, a connection between the first cell associated with the network node and the first user device; and providing the handover configuration to the first user device via the connection established between the network node and the first user device.

[0192] FIG. 8 is a block diagram of a wireless station or node (e.g., UE, user device, AP, BS, eNB, gNB, RAN node, network node, TRP, or other node) 1300 according to an example embodiment. The wireless station 1300 may include, for example, one or more (e.g., two as shown in FIG. 8) RF (radio frequency) or wireless transceivers 1302 A, 1302B, where each wireless transceiver includes a transmitter to transmit signals and a receiver to receive signals. The wireless station also includes a processor or control unit / entity (controller) 1304 to execute instructions or software and control transmission and receptions of signals, and a memory 1306 to store data and / or instructions.

[0193] Processor 1304 may also make decisions or determinations, generate frames, packets or messages for transmission, decode received frames or messages for further processing, and other tasks or functions described herein. Processor 1304, which may be a baseband processor, for example, may generate messages, packets, frames or other signals for transmission via wireless transceiver 1302 (1302A or 1302B). Processor 1304 may control transmission of signals or messages over a wireless network, and may control the reception of signals or messages, etc., via a wireless network (e.g., after being down-converted by wireless transceiver 1302, for example). Processor 1304 may be programmable and capable of executing software or other instructions stored in memory or on other computer media toperform the various tasks and functions described above, such as one or more of the tasks or methods described above. Processor 1304 may be (or may include), for example, hardware, programmable logic, a programmable processor that executes software or firmware, and / or any combination of these. Using other terminology, processor 1304 and transceiver 1302 together may be considered as a wireless transmitter / receiver system, for example.

[0194] In addition, referring to FIG. 8, a controller (or processor) 1308 may execute software and instructions, and may provide overall control for the station 1300, and may provide control for other systems not shown in FIG. 8, such as controlling input / output devices (e.g., display, keypad), and / or may execute software for one or more applications that may be provided on wireless station 1300, such as, for example, an email program, audio / video applications, a word processor, a Voice over IP application, or other application or software.

[0195] In addition, a storage medium may be provided that includes stored instructions, which when executed by a controller or processor may result in the processor 1304, or other controller or processor, performing one or more of the functions or tasks described above.

[0196] According to another example embodiment, RF or wireless transceiver(s) 1302A / 1302B may receive signals or data and / or transmit or send signals or data. Processor 1304 (and possibly transceivers 1302A / 1302B) may control the RF or wireless transceiver 1302 A or 1302B to receive, send, broadcast or transmit signals or data.

[0197] Example embodiments are provided or described for each of the example methods, including: An apparatus (e.g., 1300, FIG. 8) including means (e.g., processor 1304, RF transceivers 1302A and / or 1302B, and / or memory 1306, in FIG. 8) for carrying out any of the methods; a non-transitory computer-readable storage medium (e.g., memory 1306, FIG.8) comprising instructions stored thereon that, when executed by at least one processor (processor 1304, FIG. 8), are configured to cause a computing system (e.g., 1300, FIG. 8) to perform any of the example methods; and an apparatus (e.g., 1300, FIG. 8) including at least one processor (e.g., processor 1304, FIG. 8), and at least one memory (e.g., memory 1306, FIG. 8) including computer program code, the at least one memory (1306) and the computer program code configured to, with the at least one processor (1304), cause the apparatus (e.g., 1300) at least to perform any of the example methods.

[0198] Embodiments of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Embodiments may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storagedevice or in a propagated signal, for execution by, or to control the operation of, a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. Embodiments may also be provided on a computer readable medium or computer readable storage medium, which may be a non-transitory medium. Embodiments of the various techniques may also include embodiments provided via transitory signals or media, and / or programs and / or software embodiments that are downloadable via the Internet or other network(s), either wired networks and / or wireless networks. In addition, embodiments may be provided via machine type communications (MTC), and also via an Internet of Things (IOT).

[0199] As used in this application, the term ‘circuitry’ or “circuit” refers to all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of circuits and soft-ware (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 memory(ies) 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. This definition of ‘circuitry’ applies to all uses of this term in this application. As a further example, as used in this application, 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.

[0200] The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and / or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer, or it may be distributed amongst a number of computers.

[0201] Furthermore, embodiments of the various techniques described herein may use a cyber-physical system (CPS) (a system of collaborating computational elements controllingphysical entities). CPS may enable the embodiment and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers,...) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals. The rise in popularity of smartphones has increased interest in the area of mobile cyber-physical systems. Therefore, various embodiments of techniques described herein may be provided via one or more of these technologies.

[0202] A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit or part of it suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[0203] Method steps may be performed by one or more programmable processors executing a computer program or computer program portions to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (applicationspecific integrated circuit).

[0204] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer, chip or chipset. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0205] To provide for interaction with a user, embodiments may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a user interface, such as a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0206] Embodiments may be implemented in a computing system that includes a backend component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a frontend component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an embodiment, or any combination of such backend, middleware, or frontend components. Components may be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.

[0207] While certain features of the described embodiments have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the various embodiments.

Claims

WHAT IS CLAIMED IS:

1. 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, by a user device from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receive, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and perform, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

2. The apparatus of claim 1, wherein the cell switch comprises either a handover or a cell reselection.

3. The apparatus of any of claims 1-2, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

4. The apparatus of any of claims 1-3, wherein the message comprises a flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

5. The apparatus of any of claims 1-4: wherein the first session is a first broadcast session; wherein the apparatus caused to receive data comprises the apparatus caused to receive, by the user device that is in an idle or inactive state from the first cell to which the user device is camped-on, data associated with the first broadcast session; wherein the apparatus is further caused to receive, by the user device from the first cell, control information indicating a list of neighbor cells that are transmitting the firstbroadcast session, and a NES mode of operation indication for one or more of the neighbor cells indicating a non-NES mode of operation for the one or more neighbor cells; wherein the apparatus caused to perform the cell switch comprises the apparatus caused to perform, by the user device, cell reselection to a second cell on the list of neighbor cells that is transmitting the first broadcast session and which is indicated by the control information to be in the non-NES mode of operation.

6. The apparatus of claim 5 wherein the NES mode of operation indication indicates either a NES mode of operation or a non-NES mode of operation for each of the one or more neighbor cells.

7. The apparatus of claim 5, wherein the control information further comprises NES mode of operation indication for additional one or more of the neighbor cells indicating a NES mode of operation for the additional one or more of the neighbor cells, and wherein the apparatus caused to perform the cell reselection comprises the apparatus caused to: reject or omit, by the user device, performing cell reselection to or camping on a neighbor cell of the list of neighbor cells for which the NES mode of operation indication indicates the NES mode of operation for the rejected or omitted cell.

8. The apparatus of any of claims 5-7, wherein the control information indicating the list of neighbor cells that are transmitting the first broadcast session, and the NES mode of operation indication for one or more of the neighbor cells is received by the user device via either a system information block (SIB) information or multicast broadcast services control channel (MCCH) transmitted by the first cell.

9. The apparatus of claim 1 : wherein the first session is a first broadcast session; wherein the apparatus is further caused to: if the user device is in an idle or inactive state, establish a connection to the first cell based on the message; and transmit, by the user device to the first cell, a MBS interest indication to indicate an interest of the user device in continuing to receive the first broadcast session; andwherein the apparatus caused to perform the cell switch comprises the apparatus caused to perform, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first broadcast session and is in a non-NES mode of operation.

10. The apparatus of claim 1 : wherein the first session is a first multicast session; wherein the apparatus is further caused to: receive, by the user device from the camped-on cell, a group paging request indicating a multicast group identifier associated with the first multicast session; establish, by the user device based on the group paging request, a connection to the first cell; and wherein the apparatus caused to perform the cell switch comprises the apparatus caused to perform, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first multicast session and is in a non-NES mode of operation.

11. A method comprising: receiving, by a user device from a first cell that is either a serving cell or a camped-on cell, data associated with a first session of a multicast and / or broadcast services, MBS; receiving, by the user device from the first cell, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell; and performing, by the user device based on the message, a cell switch to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

12. The method of claim 11, wherein the cell switch comprises either a handover or a cell reselection.

13. The method of any of claims 11-12, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

14. The method of any of claims 11-13, wherein the message comprises a flag that indicates that MBS or the first session of the MBS will be impacted due to a transition of the first cell from the non-NES mode of operation to the NES mode of operation.

15. The method of any of claims 11-14: wherein the first session is a first broadcast session; wherein the receiving data comprises receiving, by the user device that is in an idle or inactive state from the first cell to which the user device is camped-on, data associated with the first broadcast session; wherein the method further comprises receiving, by the user device from the first cell, control information indicating a list of neighbor cells that are transmitting the first broadcast session, and a NES mode of operation indication for one or more of the neighbor cells indicating a non-NES mode of operation for the one or more neighbor cells; and wherein the performing the cell switch comprises performing, by the user device, cell reselection to a second cell on the list of neighbor cells that is transmitting the first broadcast session and which is indicated by the control information to be in the non-NES mode of operation.

16. The method of claim 15 wherein the NES mode of operation indication indicates either a NES mode of operation or a non-NES mode of operation for each of the one or more neighbor cells.

17. The method of claim 15, wherein the control information further comprises NES mode of operation indication for additional one or more of the neighbor cells indicating a NES mode of operation for the additional one or more of the neighbor cells, and wherein performing the cell reselection comprises: rejecting or omitting, by the user device, performing cell reselection to or camping on a neighbor cell of the list of neighbor cells for which the NES mode of operation indication indicates the NES mode of operation for the rejected or omitted cell.

18. The method of any of claims 15-17, wherein the control information indicating the list of neighbor cells that are transmitting the first broadcast session, and the NES mode of operation indication for one or more of the neighbor cells is received by the user device viaeither a system information block (SIB) information or multicast broadcast services control channel (MCCH) transmitted by the first cell.

19. The method of claim 11 : wherein the first session is a first broadcast session; the method further comprising: if the user device is in an idle or inactive state, establishing a connection to the first cell based on the message; and transmitting, by the user device to the first cell, a MBS interest indication to indicate an interest of the user device in continuing to receive the first broadcast session; and wherein the performing the cell switch comprises performing, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first broadcast session and is in a non-NES mode of operation.

20. The method of claim 11 : wherein the first session is a first multicast session; wherein the method further comprises: receiving, by the user device from the camped-on cell, a group paging request indicating a multicast group identifier associated with the first multicast session; and establishing, by the user device based on the group paging request, a connection to the first cell; and wherein the performing the cell switch comprises the performing, by the user device based on a handover configuration received by the user device from the first cell, a handover to the second cell that is transmitting the first multicast session and is in a non-NES mode of operation.

21. 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: transmit, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); andtransmit, by the network node associated with the first cell to at least a first user device, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

22. The apparatus of claim 21, wherein the cell switch comprises either a handover or a cell reselection.

23. The apparatus of any of claims 21-22, wherein the message comprises a MBS-NES flag indicating that at least one of the MBS or the first session of the MBS will be impacted by the NES mode of operation for the first cell.

24. The apparatus of any of claims 21-23, wherein the apparatus is further caused to: determine, by the network node, one or more neighbor cells that transmit the first session of the MBS and that are in a non-NES mode of operation; provide, by the network node to the first user device that is in a connected state, a handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non-NES mode of operation.

25. The apparatus of any of claims 21-24, wherein the apparatus caused to transmit data comprises the apparatus caused to: transmit, by the network node associated with the first cell that is at least one of a serving cell to one or more connected state user devices or is a camped-on cell for one or more user idle or inactive state user devices, data associated with the first session of the MBS.

26. The apparatus of any of claims 24-25, wherein the apparatus caused to determine comprises the apparatus caused to: receive, by the network node from another network node associated with one or more neighbor cells: an indication that one or more neighbor cells transmit the first session of the MBS; and a NES mode of operation indication for at least one of the one or more neighbor cells indicating a NES mode of operation that will impact the MBS.

27. The apparatus of claim 26, wherein the NES mode of operation indication provides at least one of a current and / or future NES mode of operation indication for the one or more cells, indicating at least one of a current or future NES mode of operation.

28. The apparatus of any of claims 21-27, wherein the apparatus is further caused to: transmit, by the network node to one or more user devices including the first user device, control information indicating a list of neighbor cells that are transmitting the first session of the MBS, and a NES mode of operation indication for one or more of the neighbor cells indicating either a NES mode of operation or a non-NES mode of operation for the neighbor cell, to enable the one or more user devices to perform a cell switch to one of the one or more neighbor cells that is transmitting the first session of the MBS and is in a non- NES mode of operation.

29. The apparatus of claim 28, wherein the control information indicating the list of neighbor cells that are transmitting the first session of the MBS, and the NES mode of operation indication for one or more of the neighbor cells is transmitted via either a system information block (SIB) information or multicast broadcast services control channel (MCCH).

30. The apparatus of any of claims 21-29, wherein the apparatus is further caused to: transmit, by the network node to another network node, a NES mode of operation indication for the first cell indicating a current or future NES mode of operation that will impact the MBS.

31. The apparatus of claim 24, wherein the apparatus is further caused to: establish a connection between the first cell and the first user device; receive, by the network node from the first user device, a MBS interest indication to indicate an interest of the first user device in continuing to receive the first session of the MBS; and wherein the apparatus caused to provide the handover configuration comprises the apparatus configured to provide, by the network node to the first user device based on receiving the MBS interest indication, the handover configuration for a handover of the first user device to the second cell that is transmitting the first session of the MBS and is in a non- NES mode of operation.

32. The apparatus of claim 24: wherein the apparatus is caused to transmit data comprises the apparatus caused to transmit, by the network node associated with the first cell, data associated with a first multicast session of the MBS; wherein the apparatus is caused to: transmit, by the network node to the first user device that is in an inactive or idle state, a group paging request indicating a multicast group identifier associated with the first multicast session; and establish a connection between the first cell associated with the network node and the first user device; and wherein the apparatus caused to provide a handover configuration comprises the apparatus caused to provide the handover configuration to the first user device via the connection established between the network node and the first user device.

33. The apparatus of claim 31, wherein the apparatus is caused to: transmit, by the network node to at least some of the user devices, a release request and cell reselection flag to cause the at least some of the user devices to release their connection with the first cells associated with the network node and perform cell reselection; wherein the apparatus caused to receive the MBS interest indication comprises the apparatus caused to receive, by the network node from one or more remaining user devices that are still connected to the first cell, a MBS interest indication to indicate an interest of the one or more remaining user devices in continuing to receive the first session of the MBS.

34. A method comprising: transmitting, by a network node associated with a first cell, data associated with a first session of a multicast and / or broadcast services (MBS); and transmitting, by the network node associated with the first cell to at least a first user device, a message indicating that the MBS or the first session of the MBS will be impacted due to a network energy-saving, NES, mode of operation for the first cell, thereby causing a cell switch of at least the first user device to a second cell that is transmitting the first session of the MBS and is operating in a non-NES mode of operation.

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