On-demand transmission of system information block for network energy saving (NES) cells

Abstract

The present disclosure relates to On-Demand transmission of System Information Block (SIB) for Network Energy Saving (NES) cells. In one embodiment, the present disclosure discloses a method which comprises upon detecting that a current load of one or more IDLE / INACTIVE UEs experienced by an anchor cell (or Cell A) exceeds a threshold value, offloading the one or more IDLE / INACTIVE UEs to NES cells having overlapping coverage with the anchor cell. The offloading comprises transmitting a SystemInfoModification paging message instructing the IDLE / INACTIVE UEs to evaluate radio conditions of the NES cells for performing cell re-selection to at least one NES cell, or transmitting a backhaul signaling message to at least one other gNB serving the NES cells, instructing the at least one other gNB to initiate OD-SIB1 transmission for performing cell re-selection of the IDLE / INACTIVE UEs to the at least one NES cell.

Description

[0001] ON-DEMAND TRANSMISSION OF SYSTEM INFORMATION BLOCK FOR

[0002] NETWORK ENERGY SAVING (NES) CELLS

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004]

[0001] This application claims priority to Indian provisional patent application 202441057778, filed on July 30, 2024, and Indian non-provisional patent application 202441057778, filed on February 28, 2025, the entire contents of which are incorporated herein by reference.

[0005] FIELD

[0006]

[0002] The present disclosure relates to On-Demand transmission of System Information Block (SIB) for Network Energy Saving (NES) cells.

[0007] BACKGROUND

[0008]

[0003] The information disclosed in this background section is only for enhancement of understanding of the general background of the disclosure and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

[0009]

[0004] Mobile telecommunications industry is experiencing tremendous growth, driven by ever-increasing demand for connectivity and data sendees. To meet the ever-increasing demand of connectivity and data services, the wireless communication technologies or Radio Access Technologies (RATs) are continually advancing. To meet the increasing demand of expanded connectivity and higher data capacity, the existing wireless communication systems such as 4thGeneration (4G) or Long Term Evolution (LTE) wireless communication systems are evolving into next generation wireless communication systems such as 5G or 6G wireless communication systems.

[0010]

[0005] The next generation wireless communication systems (e.g., 5G wireless communication systems) are expected to accommodate more demanding services, e.g., Extended Reality (XR), Artificial Intelligence (Al), Machine Learning (ML), etc. which may require higher energyconsumption at device side (e.g., at UE side) as well as the network side (e.g., RAN and / or CN side). Thus, the advent of next generation technologies and the widespread use of mobile devices are resulting in a substantial rise in energy consumption. Network energy7saving is of great importance for environmental sustainability7, to reduce environmental impact (greenhouse gas emissions), and for operational cost savings.

[0011]

[0006] Consequently, Third Generation Partnership Project (3GPP) standards are designed to promote loy energy consumption, not only at device side, but also at the netyvork side. New features for energy savings (also termed as “Netyvork Energy Savings” or “NES” features) have been included, which introduce various mechanisms for energy saving. One such mechanism is deployment of NES cells. The NES cells are specialized cells which stay in dormant state or sleep state to save energy.

[0012]

[0007] In a typical network deployment, UEs are primarily served by an anchor cell. However, as a number of UEs which are in RRC IDLE and / or RRC INACTIVE state (referred to as “IDLE / INACTIVE UEs”) camping on the anchor cell increases, the anchor cell may become overloaded, leading to inefficiencies in resource utilization and higher energy7consumption. Since the IDLE / INACTIVE UEs are unaware of the overload status of the anchor cell, the IDLE / INACTIVE UEs continue to camp on the anchor cell. Thus, there is a need to offload UEs from the anchor cell to NES cells.

[0013] SUMMARY

[0014]

[0008] The present disclosure discloses techniques of offloading User Equipment (UEs) camping on an anchor cell to Netyvork Energy7Saving (NES) cells that share overlapping coverage yvith the anchor cell. Such offloading mechanisms help in balancing load on the anchor cell, optimizes netw ork resource usage, prevents netw ork congestion, enhances network energy efficiency.

[0015]

[0009] In one non-limiting embodiment, the present disclosure discloses a method which comprises upon detecting that a current load of one or more IDLE / INACTIVE UEs experienced by an anchor cell (Cell A) served by a base station (gNB) exceeds a threshold value, offloading the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell. In one aspect, the offloading comprises transmitting a System Information Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell. In another aspect, the offloading comprises transmitting a backhaul signaling message to at least one other gNB serving the at least one NES cell, instructing the at least one other gNB to initiate On-Demand System Information Block Type 1 (OD-SIB1) transmission for performing cell re-selection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

[0016]

[0010] In one non-limiting embodiment, the present disclosure discloses an apparatus which is configured to upon detecting that a current load of one or more IDLE / INACTIVE UEs experienced by an anchor cell (Cell A) served by a base station (gNB) exceeds a threshold value, offload the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell. In one aspect, the offloading comprises transmitting a System Information Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell. In another aspect, the offloading comprises transmitting a backhaul signaling message to at least one other gNB serving the at least one NES cell, instructing the at least one other gNB to initiate On-Demand System Information Block Type 1 (OD-SIB1) transmission for performing cell re-selection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

[0017] [OH] In one non-limiting embodiment, the present disclosure discloses a non-transitory computer readable media storing one or more computer executable instructions which, when executed by an apparatus, cause the apparatus to upon detecting that a current load of one or more IDLE / INACTIVE UEs experienced by an anchor cell (Cell A) served by a base station (gNB) exceeds a threshold value, offload the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell. In one aspect, the offloading comprises transmitting a System Information Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell. In another aspect, the offloading comprises transmitting a backhaul signaling message to at least one other gNB serving the at least one NES cell, instructing the at least one other gNB to initiate On-Demand System Information Block Type 1 (OD-SIB1) transmission for performing cell re-selection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019]

[0012] Features, aspects, and advantages of embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements, and wherein:

[0020]

[0013] FIG. 1 illustrates an example communication system 100 in which the techniques of offloading User Equipment (UEs) from an anchor cell to NES cells may be implemented.

[0014] FIG. 2 illustrates an exemplary signaling procedures 200 for offloading one or more IDLE / INACTIVE UEs from the anchor cell to the NES cells, in accordance with some embodiments of the present disclosure.

[0021]

[0015] FIG. 3 illustrates another exemplary signaling procedures 300 for offloading the one or more IDLE / INACTIVE UEs from the anchor cell to the NES cells, in accordance with some embodiments of the present disclosure.

[0022]

[0016] FIG. 4 illustrates an exemplary’ signaling procedures 400 for handing over one or more connected UEs from the anchor cell to the NES cells, in accordance with some embodiments of the present disclosure.

[0023]

[0017] FIG. 5 illustrates a communication system 500 showing offloading of one or more UEs from the anchor cell to the NES cells, in accordance with some embodiments of the present disclosure.

[0024]

[0018] FIG. 6 illustrates a block diagram of an apparatus 600, in accordance with some embodiments of the present disclosure.

[0025]

[0019] FIG. 7 illustrates a flowchart illustrating an example method 700 for offloading one or more UEs from the anchor cell to the NES cells, in accordance with some embodiments of the present disclosure.

[0026]

[0020] FIG. 8 illustrates an example topology 800 of NES Cell and Anchor cell for OD-S1B1, in accordance with some embodiments of the present disclosure.

[0027] DETAILED DESCRIPTION

[0028]

[0021] The following detailed description of example embodiments refers to the accompanying drawings. The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise form disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of the implementations. Further, one or more features or components of one embodiment may be incorporated into or combined with another embodiment (or one or more features of another embodiment). Additionally, the flowchart and description of operations provided below relate to one of the various embodiments. It should be noted that it is possible to make other embodiments that do not exactly match the flowchart and its description. It is understood that in other embodiments one or more operations may be omitted, one or more operations may be added, one or more operations may be performed simultaneously (at least in part).

[0029]

[0022] It will be apparent that systems and / or methods, described herein may be implemented in different forms of hardware, software, or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and / or methods is not limiting of the implementations. Thus, the operation and behavior of the systems and / or methods are described herein without reference to specific software code. It is understood that software and hardware may be designed to implement the systems and / or methods based on the description herein.

[0030]

[0023] Even though particular combinations of features are recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of implementations. In fact, many of these features may be combined in ways not specifically recited in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of implementations includes each dependent claim in combination with every other claim in the claim set.

[0031]

[0024] No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Also, as used herein, the tenns “‘has,” “have,” “having,” “‘include,” “including.” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Furthermore, expressions such as “at least one of [A] and [B],” “[A] and / or [B],” or “at least one of [A] or [B] ” are to be understood as including only A, only B, or both A and B.

[0032]

[0025] The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the implementations to the precise form disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of the implementations.

[0033]

[0026] In the present disclosure, the terms like “communication system”, “system”, “wireless communication system” have been used interchangeably throughout the specification. The terms like “anchor cell”, “Cell A” and “non-NES cell” may be used interchangeably throughout the description. The terms like “NES cell” and “non-anchor cell” may be used interchangeably throughout the description. The terms like “idle UE” and “idle mode UE” may be used interchangeably throughout the description. The terms like “inactive UE” and “inactive mode UE” may be used interchangeably throughout the description. It may be noted that the phrase “IDLE / INACTIVE UEs” used in the present disclosure covers one or more of: at least one IDLE mode UE, at least one INACTIVE mode UE, or a combination of at least one IDLE mode UE and at least one INACTIVE mode UE.

[0034]

[0027] In the context of present disclosure, different Radio Resource Control (RRC) states of a User Equipment (UE) include RRC IDLE state (also referred to as “idle state”), RRC INACTIVE state (also referred to as “inactive state”), and RRC CONNECTED state (also referred to as “connected state”), as defined by the 3GPP. A UE which is in the RRC CONNECTED state may be called a “connected UE” or “connected mode UE”, a UE which is in the RRC IDLE state may be called an “idle UE” or “idle mode UE”, and a UE which is in the RRC_INACTIVE state may be called an “inactive UE” or “inactive mode UE”.

[0028] The RRC CONNECTED state is where the UE actively communicates with a network (or a base station) and has an established RRC connection. The UE remains in the RRC_CONNECTED state as long as there is an active data transmission, and when there is no active data transmission, the UE may move to the RRC INACTIVE or RRC IDLE state to conserve resources. The RRC IDLE state is a low-power state where a UE is not actively communicating with the network but can still receive system information and paging messages. In RRC IDLE state, the UE does not have an active RRC connection. The UE moves to RRC CONNECTED state when there is uplink or downlink data to be sent (triggered by paging) and remains in RRC IDLE state if there is no data activity.

[0035]

[0029] In RRC INACTIVE state, the UE has an inactive RRC connection which means the UE does not need to re-establish full RRC procedures when resuming activity . UE’s context is stored in both the base station and the UE, which allows for faster reactivation. The UE moves to RRC_CONNECTED state when uplink or downlink data transmission is required and moves to RRC IDLE state if the network decides to fully release the RRC context due to inactivity. It may be noted that in both RRC IDLE and RRC CONNECTED states, the UE is still reachable via paging.

[0036]

[0030] In the context of present disclosure, the term “dormant UEs’’ refer to those UEs which are in RRC IDLE state and / or in RRC IN ACTIVE states. The dormant UEs are not actively engaged in data transmission and help conserve network and device energy by reducing unnecessary signaling and resource allocations.

[0037]

[0031] In the context of present disclosure, System Information Blocks (SIBs) refer to downlink broadcast messages or information blocks transmitted periodically by a base station to UEs. The SIBs comprise information relevant when evaluating whether a UE is allowed to access a cell and defines scheduling of other system information. A UE needs the SIB for cell camping when the UE is powered on, and for cell selection and cell re-selection when the UE is in RRC IDLE mode. The SIB provides all necessary details like system frame number, system bandwidth, Public Land Mobile Network (PLMN), cell selection and re-selection thresholds, and the like, to access a network. The SIB also indicates whether one or more SIBs are only provided on-demand. In such case, the SIB may also provide Physical Random Access Channel (PRACH) configuration needed by the UE to request for a required or On-Demand SIB (OD-SIB).

[0038]

[0032] In an effort to enhance energy efficiency, the 3rd Generation Partnership Project (3GPP) is introducing new features for energy savings or reducing power consumption in networks. For example, much longer durations and higher ratio of discontinuous transmission (DTX) is supported in New Radio (NR) compared to the 3GPP Long Term Evolution (LTE) standard. Another possible network energy saving feature under discussion in 3GPP is transmitting SIBs on-demand, rather than periodic broadcasting / transmissions. To enable this feature, the 3GPP has introduced the concept of Network Energy Saving (NES) cells. The NES cells are those cells which do not periodically transmit broadcast signals, thereby reducing network energy consumption. Specifically, 3GPP, Release 19 has a work item for Network Energy Savings with an objective to implement On-Demand System Information Block Type 1 (OD-SIB 1) transmission. This mechanism allows configured NES cells to transmit SIB1 selectively in response to specific UE triggers such as Uplink Wake-Up (UL WUS) signals transmitted over existing uplink channels.

[0039]

[0033] In the context of present disclosure, an '“anchor cell” or a “‘Cell A” is a cell where a UE is capable of receiving Synchronization Signal Block (SSB), system information, and paging. The anchor cell periodically transmits system information (e.g.. at least its own SIB 1 ) to UEs. Conversely, a “non-anchor cell” or a “NES cell” is a cell without periodic transmission of svstem information.

[0034] A NES cell without periodic transmission of SIB1 is a cell where a UE cannot receive the SIB1 all the time (or periodically) like in a normal cell. Such cell may also be referred to as a “SIB-less cell”. A NES cell without periodic transmission of SSB and SIB1 is a cell where a UE receives neither SSB nor SIB1. In other words, some NES cells may not periodically transmit SIB as well as SSB for further energy saving. Such cells may also be referred to as “SIB / S SB-less cells”. It may be noted that the concept of a NES cell without periodic SIB1 transmission is only applicable in multi-carrier scenarios, wirere a UE is in a coverage of an anchor cell and one or more NES cells.

[0040]

[0035] Depending on a network design, UE access may occur only via anchor cell and / or directly in the NES cell. If a direct access to a non-anchor cell is supported, the SIB1 transmitted by anchor cell may also include the necessary information to send a w ake up signal and access the NES cell. The anchor cell periodically transmits at least its own SIB1 to the UE. However, the NES cell may transmit SIB1 in response to a wake-up signal received from the UE.

[0041]

[0036] FIG. 1 illustrates an example communication system 100 in which the techniques of offloading UEs from an anchor cell (or Cell A) to NES cells of the present disclosure may be implemented. The communication system 100 may comprise one or more base stations 102, 104 which may be communicating with a plurality of UEs 110. The one or more base stations 102, 104 serve as centralized radio access points, responsible for managing communication within their respective coverage areas. The base stations 102, 104 facilitate downlink (from base stations to UEs) and / or uplink (from UEs to base stations) transmission.

[0042]

[0037] In the context of a fourth generation (4G) Long Term Evolution (LTE) communication system, a base station 102, 104 may be referred to as an “evolved NodeB” or “eNodeB.” and in the context of a fifth generation (5G) communication system, the base station may be referred to as a “gNodeB” or ’gNB". A distributed gNB can be partitioned into one or more networking applications which may include one or more central unit entities (CUs), one or more distributed unit entities (DUs), and one or more radio units (RUs). The one or more RUs may be deployed in a physical location where radio coverage is to be provided to the plurality of UEs 110. In the present disclosure, the term “base station” may be interchangeably used with “gNB” and / or “eNB”.

[0043]

[0038] The communication system may comprise a plurality' of cells 106, 108, which represent distinct coverage areas managed by the base stations 102, 104. Each base station may serve one or more cells, depending on a network topology and a deployment strategy. Each cell of the plurality of cells 106, 108 may denote a logical communication entity7utilized for establishing connectivity7with one or more respective base stations 102, 104 (e.g., through a specific carrier frequency). The cell may be uniquely identified using an identifier that differentiates the cell from other neighboring cells. Such identifier may include a Physical Cell Identifier (PCID), a Virtual Cell Identifier (VCID), or other cell-specific identifiers. In certain scenarios, the term “cell” may also refer to a coverage area within which the logical communication entity operates or serves the plurality of UEs 110.

[0044]

[0039] The plurality of UEs 110 are distributed across the plurality of cells 106, 108 and may include any mobile or non-mobile computing device including, but not limited to, a phone (e.g., a cellular phone or smart phone), a pager, a laptop computer, a desktop computer, a wireless handset, a portable communication device, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g.. a music or video device, or a satellite radio), a global positioning system device, or any other suitable computing device including a wired or wireless communications interface. In some embodiments of the present disclosure, the plurality of UEs

[0045] 110 may include Intemet-of-Things (loT)-enabled device including, but not limited to, vehicles configured to communicate with the base stations or a core network.

[0040] Though not explicitly shown in FIG. 1, the communication system 100 may comprise a core netw ork (CN) and a Radio Access Netw ork (RAN). The CN orchestrates the various network functions and sendees. The CN employs virtualized network functions (VNFs) and software-defined networking (SDN) principles to provide flexible and scalable connectivity services. The RAN serves as a bridge between the CN and the one or more UEs 110. The RAN may include the one or more base stations 102, 104 to deliver high-speed, low-latency wireless connectivity to the one or more UEs 110.

[0046]

[0041] FIG. 1 illustrate an example scenarios where the plurality of cells 106, 108 may include an anchor cell or Cell A 106 served by a base station 102 (also referred to as an '‘anchor base station”) and one or more NES cells 108 served by respective base stations 104 (also referred to as “non-anchor base stations” or '‘NES base stations”). The cells (the anchor cell 106 and the NES cells 108) are configured to serve the plurality of UEs 110. The anchor cell 106 is configured to periodically transmit at least its own SIB 1. The NES cells 108 stay in dormant state or sleep state to save energy, until a wake-up signal is received. The NES cells 108 may be configured to perform SIB1 transmissions in response to an Uplink Wake-up Signal (UL WUS). Each of the plurality of UEs 110 may be in different RRC states depending on their activity.

[0047] 1042] The plurality of UEs 110 primarily establish connection with the anchor cell 106, which serves as the main point of access for network services. The anchor cell 106 is responsible for providing coverage that is required for the plurality of UEs 110 and is responsible for periodically transmitting essential system information, maintaining synchronization, and managing mobility procedures. Elowever, as the number of dormant UEs (i.e., the UEs which are in idle and / or inactive modes, also referred to as 'TDLE / INACTIVE UEs”) increases, the anchor cell 106 may become overloaded due to the accumulation of passive connections. This overload not only results in inefficient resource allocation but also leads to increased power consumption as the anchor cell 106 continues to sen e a large number of IDLE / INACTIVE UEs. In one example, the overload may arise due to increased paging overhead, signaling overhead, cell reselection events, etc. due to the IDLE / INACTIVE UEs. The overload may be defined in terms of a number of IDLE / INACTIVE UEs camping on the anchor cell 106.

[0048]

[0043] Overload in the anchor cell 106 may arise due to multiple factors such as UE transitions between different RRC states, when NES mode is enabled in neighboring cells, but not limited thereto. For example, consider that a UE of the plurality of UEs 110 is under the coverage of the anchor cell 106. When the UE is in connected state, the UE actively exchanges data with the network (or base station), utilizing radio resources assigned by the anchor cell 106. If there is no data transmission for a certain period, the UE may transition to inactive or idle state to conserve network and UE power. Since such dormant UEs (IDLE / INACTIVE UEs) still need system information updates (e g., paging, cell reselection information, etc ), the IDLE / INACTIVE UEs remain camped on the anchor cell 106 instead of being fully disconnected. As the number of such dormant UEs (IDLE / INACTIVE UEs) increases, the anchor cell 106 experiences a higher load which may lead to a potential overload scenario.

[0049]

[0044] Another possible overload scenario occurs when an operator decides to switch off periodic SIB transmissions in a cell 108 and enable NES mode in the cell 108. As discussed previously, the NES cells do not periodically transmit SIB and remain in sleep state unless woken up by a wakeup signal. However, when the periodic SIB transmission is disabled in the cell 108, UEs 110 served by the cell 108 cannot directly camp on the same cell 108 (which is converted into NES cell) due to lack of required system information for cell selection. Thus, the UEs which were previously camping on the NES cell 108, perform cell reselection and start camping on the anchor cell 106 which is having overlapping coverage with the NES cell 108. As a result, the anchor cell 108 is now serving a larger number of IDLE / INACTIVE UEs, leading to the potential overload scenario.

[0045] A key challenge in such overload scenarios is that the UEs 110 are not aware of overloading of the anchor cell 106. As a result, the UEs 110 continue to camp on the anchor cell 106, leading to network congestion, inefficient resource utilization, and increased overall energy7consumption.

[0050]

[0046] The present disclosure discloses various techniques of proactively offloading some or all of the plurality of UEs 110 to the NES cells 108 having overlapping coverages with the anchor cell 106. The techniques of offloading the UEs from the anchor cell 106 to the one or more NES cells 108 are discussed in the forthcoming paragraphs.

[0051]

[0047] FIG. 2 illustrates an exemplary signaling procedures 200 for offloading one or more IDLE / INACTIVE UEs 110 from the anchor cell 106 to the one or more NES cells 108, in accordance with some embodiments of the present disclosure.

[0052]

[0048] The procedure starts at Step 1, a plurality of UEs 110 are currently camping or served by the anchor cell or Cell A 106 associated with the anchor gNB 102. The plurality of UEs 110 may include one or more dormant UEs (i.e., IDLE / INACTIVE UEs) and one or more connected UEs. The one or more connected UEs may be actively transmitting and / or receiving data, while the one or more IDLE / INACTIVE UEs may not be actively transmitting but are still camping on the anchor cell 106 for paging and cell reselection purpose. Some or all of the one or more IDLE / INACTIVE UEs may be offloaded to one or more of the NES cells 108 served by the neighbouring or NES gNBs 104, which operate in a low-power state and do not periodically transmit SIB1 unless explicitly woken up.

[0053]

[0049] In Step 2, the gNB 102 associated with the anchor cell 106 may determine a cunent load experienced by the anchor cell 106. The current load may be determined in multiple ways.

[0054] In one example, the current load may be determined based on a number of one or more

[0055] IDLE / INACTIVE UEs camping on the anchor cell 106. In one example, the gNB 102 may proactively and periodically measure the current load on the anchor cell 106. In another example, the gNB 102 may measure the current load in response to certain events such as when there is a sudden increase in a number of the IDLE / INACTIVE UEs served by the anchor cell 106.

[0056]

[0050] Upon detecting that the current load experienced by the anchor cell 106 exceeds a threshold value (e.g., an overload threshold value), the gNB 102 initiates offloading of the one or more IDLE / INACTIVE UEs to at least one NES cell 108 of the one or more NES cells 108. The one or more NES cells 108 have overlapping coverage with the anchor cell 106 and may be served by one or more neighboring gNBs 104. The gNB 102 may transmit a paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells 108 for performing cell re-selection to the at least one NES cell 108 of the one or more NES cells 108, as further described in the forthcoming paragraphs.

[0057]

[0051] In Step 3, once overload is detected in the anchor cell 106, the gNB 102 may identify the one or more NES cells 108 (or the gNBs 104) within the coverage area of the anchor cell 106, which can accommodate the one or more IDLE / INACTIVE UEs. The gNB 102 may modify or update its SIB to include information of the one or more NES cells 108 to which offloading is intended to be performed. The information comprises a list of the one or more NES cells 108 or PCIs of the one or more NES cells 108 to which offloading is to be performed. In one example, the information may also comprise a cause or an indication of offloading (e.g., ■'Overload Based Offloadmg”) to notify the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells 108 for performing the cell re-selection to the at least one NES cell 108 of the one or more NES cells 108 when a predefined Radio Resource Management (RRM) criteria is satisfied. The modified SIB may be either SIB 1 or another SIB which can be acquired by the one or more IDLE / INACTIVE UEs.

[0058]

[0052] It may be noted that there may be multiple NES cells 108 having overlapping coverage with the anchor cell 106 and offloading is performed to suitable NES cells only from the one or more NES cells 108. The gNB may dynamically identify the suitable NES cell(s) based on one or more factors such as coverage overlap with the anchor cell 106, density of IDLE / INACTIVE UEs in different regions, load distribution among multiple NES cells 108, cell reselection parameters so that NES cell(s) meet required signal quality7thresholds, but not limited thereto.

[0059]

[0053] In Step 4, the gNB 102 may transmit (or broadcast) a paging message with System Information Modification (i.e., paging with the modified SIB) to the one or more IDLE / INACTIVE UEs. The paging message instructs or prompts the one or more IDLE / INACTIVE UEs to read the modified or updated SIB and evaluate radio conditions of the one or more NES cells 108 for performing the cell re-selection. The paging message may be a System Information Modification (SystemlnfoModification) paging message.

[0060]

[0054] In Step 5, upon receiving the SystemlnfoModification paging message, the one or more IDLE / INACTIVE UEs read the modified SIB, which includes at least the PCIs of the one or more NES cells 108. The one or more IDLE / INACTIVE UEs may measure or evaluate radio conditions of the one or more NES cells 108 based on one or more cell selection criteria e.g., using Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), Signal-to-Interference-plus-Noise Ratio (SINR) etc. Based on a result of the evaluation, each of the one or more UEs determine whether cell-reselection to any of the one or more NES cells 108 is possible. Consider that at least one NES cell 108 of the one or more NES cells 108 is identified to which cell-reselection is possible and eligible IDLE / INACTIVE UEs (i.e., those meeting the reselection criteria) may proceed with cell-reselection to the at least one NES cell 108. Here it is assumed that all of the one or more IDLE / INACTIVE UEs are eligible for cell- reselection. However, the present disclosure is not limited thereto and in one example, at least one IDLE / INACTIVE UE of the one or more IDLE / INACTIVE UEs may be eligible for cell reselection and the subsequent steps may be performed by / for the at least one IDLE / INACTIVE UE.

[0061]

[0055] In Step 6, the one or more IDLE / INACTIVE UEs which are eligible for cell-reselection may initiate Uplink Wake-Up Signal (UL WUS) procedure. Specifically, the one or more IDLE / INACTIVE UEs may transmit UL WUSs to their respective NES cell(s) of the at least one NES cell 108. The UL WUS are transmitted via Physical Random Access Channel (PRACH) as part of an initial access procedure. The UL WUSs may be configured to wake up the at least one NES cell 108 for initiating transmission of the OD-SIB1. Generally, a UL WUS refers to a Layer 1 (LI) signaling transmitted by a UE to notify / request a base station to wake up from a sleep state. It may be noted that each of the one or more IDLE / INACTIVE UEs already have UL WUS configurations for target NES cell(s) of the at least one NES cell 108.

[0062]

[0056] In Step 7, the at least one NES cell 108, upon receiving the UL WUS from their associated IDLE / INACTIVE UE(s), initiate a Random Access (RACH) response procedure. Specifically, each of the at least one NES cell 108 may process the received UL WUS(s) to wake up from sleep mode and respond or acknowledge via RACH Response Message.

[0063]

[0057] In Step 8, once awake, the at least one NES cell 108 may start transmitting the OD- SIB1 to the one or more IDLE / INACTIVE UEs. The OD-SIBls may carry critical information required for the one or more IDLE / INACTIVE UEs to access the at least one NES cell 108. The information carried by the OD-SIB1 may include cell sei ection / resel ection related information, cell access related information. PLMN related information, PCIs, but not limited thereto.

[0064]

[0058] In Step 9, the one or more IDLE / INACTIVE UEs acquire the OD-SIBl(s) transmitted by their identified NES cell(s) 108 and perform cell re-selection process to move from the anchor cell 106 to the at least one NES cell 108.

[0059] In Step 10, the one or more IDLE / INACTIVE UEs complete the cell-reselection process and start camping on the at least one NES cell 108. This offloading of the one or more IDLE / INACTIVE UEs from the anchor cell 106 to the at least one NES cell 108 reduces and balances load on the anchor cell 106 thereby freeing up resources for the one or more connected UEs.

[0065]

[0060] FIG. 3 illustrates another exemplary signaling procedures 300 for offloading one or more IDLE / INACTIVE UEs 110 from the anchor cell 106 to the one or more NES cells 108, in accordance with some embodiments of the present disclosure.

[0066]

[0061] The Steps 11-12 of the procedure 300 are same as Steps 1-2 of the procedure 200. In Step 11, a plurality of UEs 110 are currently camping or served by the anchor cell 106. The plurality of UEs 110 may include one or more dormant UEs (i.e., IDLE / INACTIVE UEs) and one or more connected UEs. In Step 12, the gNB 102 may determine a current load experienced by the anchor cell 106 based on a total number of the one or more IDLE / INACTIVE UEs camping on the anchor cell 106.

[0067]

[0062] Upon detecting that the current load experienced by the anchor cell 106 exceeds the threshold value, the gNB 102 initiates offloading of the one or more IDLE / INACTIVE UEs to at least one NES cell 108 of the one or more NES cells 108. The one or more NES cells 108 have overlapping coverage with the anchor cell and may be served by one or more neighboring gNBs 104. Here, the gNB 108 may transmit backhaul signaling messages to the one or more neighboring gNBs 104 serving the one or more NES cells 108. The signaling message instructs the one or more neighboring gNBs 104 to initiate OD-SIB1 transmission for performing cell re-selection of the one or more IDLE / INACTIVE UEs to the one or more NES cells 108, as further described in the forthcoming paragraphs.

[0068]

[0063] In Step 13, once overload is detected in the anchor cell 106. the gNB 102 may identify the one or more NES cells 108 (or the gNBs 104) within the coverage area of the anchor cell 106, which can accommodate the one or more IDLE / IN ACTIVE UEs. The gNB 102, instead of relying on the one or more IDLE / INACTIVE UEs to wake up the one or more NES cells 108, sends backhaul signaling messages (e.g., over Xn interface) to the one or more neighboring gNBs 104 serving the one or more NES cells 108. Each backhaul signaling message may comprise instruction to initiate OD-SIB 1 transmission from a corresponding NES cell. The backhaul signaling message may further comprise PCIs of the corresponding NES cell so that only relevant NES cell activate OD-SIB1 transmission, a cause for offloading (e.g., “Overload Based Offloading’), an expected number of IDLE / INACTIVE UEs to be offloaded so that the corresponding NES cell’s gNB may allocate sufficient resources.

[0069]

[0064] In Step 14, upon receiving the backhaul signaling messages, the one or more gNBs 104 of the one or more NES cells 108 may start transmitting the OD-SIB Is to the one or more IDLE / INACTIVE UEs. The OD-SIB Is may cany' critical information required for the one or more IDLE / INACTIVE UEs to access the one or more NES cells 108. The information earned by the OD-SIB 1 may include the cell selection / reselection related information, the cell access related information, the PLMN related information, the PCIs, but not limited thereto.

[0070]

[0065] In one example, the gNB 102 may also transmit (or broadcast) a message to the one or more IDLE / INACTIVE UEs instructing the one or more IDLE / INACTIVE UEs to read OD- SIB 1 transmitted by the one or more NES cells 108 and evaluate radio conditions of the one or more NES cells 108 to perform the cell re-selections. The one or more IDLE / INACTIVE UEs may measure or evaluate the radio conditions of the one or more NES cells 108 based on the one or more cell selection criteria. Based on a result of the evaluation, each of the one or more UEs determine whether cell-reselection to any of the one or more NES cells 108 is possible. Consider that at least one NES cell 108 of the one or more NES cells 108 is identified to which cell-reselection is possible and eligible IDLE / INACTIVE UEs (i.e.. those meeting the reselection criteria) may proceed with cell-reselection to the at least one NES cell 108.

[0066] In Step 15, the one or more IDLE / INACTIVE UEs may acquire the OD-SIBl(s) transmitted by their identified NES cell(s) 108 and perform cell re-selection process to move from the anchor cell 106 to the at least one NES cell 108.

[0071]

[0067] In Step 16, the one or more IDLE / INACTIVE UEs complete the cell-reselection process and start camping on the at least one NES cell 108. This offloading of the IDLE / INACTIVE UEs from the anchor cell 106 to the at least one NES cell 108 reduces and balances load on the anchor cell 106 thereby freeing up resources for actively connected UEs. The anchor cell 108 directly coordinates with the one or more NES cells 108 via backhaul signaling, which facilitates immediate OD-SIB1 transmissions from the NES cells 108. Since the one or more IDLE / INACTIVE UEs do not transmit UL WUSs to the one or more NES cells 108, uplink resource usage is minimized and signaling load is also reduced.

[0072]

[0068] It may be noted that the procedures 200 and 300 of UE offloading are mainly applicable for IDLE / INACTIVE UEs (i.e., the UEs which are in idle and / or inactive states). A different mechanism is needed to handle UEs which are transitioning from an RRC_CONNECTED state to either RRC IDLE or RRC INACTIVE state while ensuring efficient energy savings and load distribution in the communication system, as discussed in the forthcoming paragraphs.

[0073]

[0069] The gNB 102 of the anchor cell 106 may continuously monitor states of the one or more connected UEs being served by the anchor cell 106. When a UE has no data to transmit or receive for a certain time duration, the UE may initiate state transition to the RRC_IDLE state (if the UE is entirely inactive and releases all context at the gNB) or the RRC INACTIVE state (if the UE context is preserved at the gNB 102). The gNB 102 detects such state transition events and prepares to offload the UE to a suitable NES cell before the UE enters into the idle or inactive state.

[0074]

[0070] The gNB 102 proactively provides necessary infonnation to the UE for cell-reselection at the time of RRC release, instead of using the SIB modification and paging-based approach. The gNB 102 may transmit an “RRC Release message’' to the UE, explicitly including UL WUS configuration for the UE to directly request OD-SIB1 transmission from one or more NES cells 108. The UL WUS configuration may include PCIs of the one or more NES cells 108. The one or more NES cells 108 are target NES cells where the UE attempts to move after transitioning to the idle or inactive state. The UL WUS configuration may define procedures for the UE to send UL WUS(s) to the one or more NES cells 108 to request OD-SIB1 transmissions. It may be noted here that after receiving the UL WUS configuration and the PCIs of the one or more NES cells 108, the UE may utilize the procedure 200 to perform cell re-selection process to move from the anchor cell 106 to the suitable NES cell 108, which is briefly discussed in the forthcoming paragraphs.

[0075]

[0071] After receiving the UL WUS configuration and the PCIs of the one or more NES cells 108, the UE may measure or evaluate radio conditions of the one or more NES cells 108 to determine whether cell -res el ection to any of the one or more NES cells 108 is possible. Consider that at least one NES cell 108 of the one or more NES cells 108 is identified to which cell-reselection is possible. The UE may immediately transmit UL WUSs to the at least one NES cell 108 (which may be referred to as “at least one first NES cell”). The at least one NES cell 108 may process the received UL WUS to wake up from sleep mode and respond via RACH Response Message. Once awake, the at least one NES cell 108 may start transmitting the OD-SIB1 to the UE. The UE may acquire the OD-SIB1 and perform cell re-selection process to move from the anchor cell 106 to a suitable NES cell of the at least one NES cell 108

[0076]

[0072] Finally, the UE may start camping on the NES cell, thereby reducing the load on the anchor cell 106. Here, unlike already IDLE / INACTIVE UEs (which require SIB modification and paging). UL WUS configuration is preassigned at the time of RRC release which significantly reduces signaling overhead on the anchor cell. Further, the UEs transitioning to idle or inactive states do not camp on the anchor cell first and later reselect NES cells 108. Instead, such UEs directly trigger offloading via UL WUS and OD-SIB1 acquisition, making the offloading process faster and more efficient.

[0077]

[0073] In one non-limiting embodiment, the techniques described herein may facilitate handover of connected state UEs from an overloaded anchor cell 106 to NES cells 108 that have overlapping coverages.

[0078]

[0074] FIG. 4 illustrates an exemplar}’ signaling procedures 400 for handing over one or more connected UEs 110 from the anchor cell 106 to the one or more NES cells 108, in accordance with some embodiments of the present disclosure.

[0079]

[0075] The procedure starts at Step 21, a plurality of UEs 110 are currently camping or served by the anchor cell 106 associated with the gNB 102. The plurality of UEs 110 may include one or more dormant UEs (i.e., IDLE / INACTIVE UEs) and one or more connected UEs. The one or more connected UEs may be actively transmitting and / or receiving data.

[0080]

[0076] In Step 22, the gNB 102 associated with the anchor cell 106 may determine a current load experienced by the anchor cell 106. Upon detecting that the current load experienced by the anchor cell 106 exceeds the threshold value, the gNB 102 initiates handover of at least one connected UE from the one or more connected UEs to at least one NES cell 108 of the one or more NES cells 108.

[0081]

[0077] In Step 23, once overload is detected in the anchor cell 106, the gNB 102 may identify the one or more NES cells 108 (or the gNBs 104) within the coverage area of the anchor cell 106, which can accommodate the at least one connected UE. The gNB 102 may modify or update its SIB to include information of the one or more NES cells which are potential candidates for handover. The information comprises a list of the one or more NES cells or PCIs of the one or more NES cells. In one example, the information may also comprise a cause or an indication of offloading (e.g., ‘“Overload Based Handover”) to notify the one or more connected UEs to evaluate radio conditions of the one or more NES cells 108 for performing handover to at least one NES cell of the one or more NES cells. The modified SIB is either SIB 1 or another SIB acquired by the at least one connected UE.

[0082]

[0078] In Step 24, the gNB 102 may transmit an RRC message with System Information Modification to the one or more connected UEs instructing the one or more connected UEs to read the modified or updated SIB and evaluate radio conditions of the one or more NES cells 108 for performing handover.

[0083]

[0079] In Step 25, upon receiving the RRC message, the one or more connected UEs read the modified SIB, which includes at least the PCIs of the one or more NES cells 108. The one or more UEs may measure or evaluate radio conditions of the one or more NES cells 108 and determine whether handover to any of the one or more NES cells 108 is possible. Consider that at least one NES cell 108 of the one or more NES cells 108 is identified to which handover is possible and eligible connected UEs (i.e., those meeting the handover criteria) may proceed with handover to the at least one NES cell 108. Here, the at least one NES cell 108 may also be referred to as "at least one second NES cell”. Also, it is assumed that all of the one or more connected UEs are eligible for handover. However, the present disclosure is not limited thereto and in one example, at least one connected UE of the one or more connected UEs may be eligible for handover and the subsequent steps may be performed by / for the at least one connected UE.

[0084]

[0080] In Step 26. the one or more connected UEs which are eligible may transmit UE WUSs for OD-SIB1 transmissions from their respective NES cell(s) of the at least one NES cell 108. The UL WUS are transmitted via Physical Random Access Channel (PRACH) as part of an initial access procedure.

[0081] In Step 27, the at least one NES cell 108, upon receiving the UL WUS from their associated connected UE(s) may process the received UL WUS(s) to wake up from sleep mode and respond via a Response Message, acknowledging request for sendee.

[0085]

[0082] In Step 28, once awake, the at least one NES cell 108 may start transmitting the OD- SIB1 to the one or more connected UEs. The OD-SIBls may cany' critical information required for the one or more connected UEs to access the at least one NES cell 108.

[0086]

[0083] In Step 29, the one or more connected UEs acquire the OD-SIBl(s) transmitted by their identified NES cell(s) 108 and perform measurements related to signal strengths and quality of the at least one NES cell 108. Each connected UE sends a measurement report to the gNB 102 of the anchor cell 106. The measurement report may include measured RSRP, RSRQ, and / or SINR of the anchor cell and at least one NES cell 108. Based on the measurement reports received from the at least one connected UE, the gNB 102 may determine a best NES cell for each of the at least one connected UE and triggers RRC Reconfiguration and handover signaling. For each of the at least one connected UE, the gNB 102 may send an RRC Reconfiguration message to the UE instructing the UE to perform handover to a selected NES cell. The UE then performs handover to the selected NES cell to reduce load on the anchor cell 106 thereby freeing up resources for other UEs.

[0087]

[0084] In the above described procedures, the current load experience by the anchor cell 106 is determined based on the number of one or more IDLE / INACTIVE UEs camping on the anchor cell 106. However, the present disclosure is not limited thereto and in another example, the current load of the anchor cell 106 may be indicative of an overall load on the anchor cell 106 and may be determined based on a count of total UEs served by the anchor cell 106 and various other parameters such as Physical Resource Block (PRB) utilization, number of active bearers, RRC signaling load, but not limited thereto.

[0085] In this manner, the present disclosure discloses techniques of efficiently offloading and / or handing over UEs from an overloaded anchor cell 106 to NES cells 108 which reduces and balances load on the anchor cell 106 and also frees up resources for other UEs served by the anchor cell. By offloading the UEs to the NES cells 108, network congestion may be prevented, signaling load on the anchor cells may be reduced, network resource utilization or usage may be optimized, and overall energy' consumption and energy' efficiency in the communication system / network may be improved. Thus, the techniques of the present disclosure provide seamless UE transitions while maintaining network performance and reducing energy consumption in the network.

[0088]

[0086] FIG. 5 illustrates an example communication system 500 showing offloading of UEs from an anchor cell to NES cells. The communication system 100 may7include an anchor cell 106 served by an anchor gNB 102, a first NES cell 108-1 served by a first NES gNB 104-1, and a second NES cell 108-2 served by a second NES gNB 104-2. Consider that initially, the anchor gNB 102 is serving a plurality of UEs 110-1, 110-2, . . . , 110-i (collectively denoted as UEs 110). Upon detecting overload on the anchor cell 106, the anchor gNB 102 may decide to offload some of the plurality7of UEs 110 to the NES cells 108-1, 108-2. As shown in FIG. 5, the UE 110-1 and UE 110-2 are within the coverage of the anchor cell 106, the UE 110-3 is within the coverage of the anchor cell 106 and the first NES cell 108-1, and the UE 110-4 and UE 110-5 are within the coverage of the anchor cell 106 and the second NES cell 108-2. Further, consider that the UE 110-5 is within the coverage of the anchor cell 106. the first NES cell 108- 1, and the second NES cell 108-2.

[0089]

[0087] In a first example, consider that the UEs 110-1, 110-3. 110-4, and 110-6 are in dormant (idle and / or inactive) states, while the UEs 110-2 and 110-5 are currently in connected states. Upon detecting the overload on the anchor cell 106, the anchor gNB 102 may offload the IDLE / INACTIVE UE 110-3 to the first NES cell 108-1 and offload UE 110-4 to the second NES cell 108-2(e.g., using the procedure 200 or 300). Further, for the UE 110-6, there are two candidate NES cells 108-1 and 108-2. Consider that the UE 110-6 evaluates radio conditions of the NES cells 108-1 and 108-2 based on the one or more cell selection criteria and identifies that the first NES cells 108-1 is best candidate NES cell for the UE 110-6. The gNB may then facilitate offloading of the IDLE / INACTIVE UE 110-6 to the first NES cell 108-1 (e.g., using the procedure 200 or 300). Consider that the UE 110-5 is transitioning from the connected state to idle or inactive state. The gNB 102 may perform offloading of the UE 110-5 to the second NES cell 108-2 by transmitting the “RRC Release message” to the UE 110-5, explicitly including UL WUS configuration for the UE 110-5 to directly request the OD-SIB1 transmission from NES cells e.g., from the second NES cell 108-2.

[0090]

[0088] In a second example, consider that at least the UEs 110-1, 110-2, and 110-3 are in dormant (idle and / or inactive) states, while the UEs 110-4 to 110-6 are in connected states. Upon detecting the overload on the anchor cell 106, the anchor gNB 102 may offload the IDLE / INACTIVE UE 110-3 to the first NES cell 108-1 (e.g., using the procedure 200 or 300). Further, forthe UEs 110-1 and 110-2, offloading is not possible because there is no overlapping NES cell for the UEs 110-1 and 110-2. The anchor gNB 102 may further handover one or more of the connected UEs 110-4 to 110-6 to the first or second NES cells, as applicable (e.g., using the procedure 400). In this manner, the techniques of the present disclosure efficiently offloads and / or handing over UEs from an overloaded anchor cell 106 to NES cells 108.

[0091]

[0089] FIG. 6 illustrates a block diagram of an apparatus or device 600, in accordance with some embodiments of the present disclosure. As shown in FIG. 6. the apparatus 600 may include a processor 610, a memory 620, a storage component 630, an input component 640, an output component 650, a communication interface 660, a bus 670, but not limited thereto.

[0092]

[0090] The processor 610. as used herein, means any type of computational circuit that may comprise hardware elements and software elements. The processor 610 may be embodied as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and / or one or more single core processors, a distributed processing system, or the like. The processor 610 may be a Central Processing Unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), an application-specific integrated circuit (ASIC), or another type of processing component.

[0093]

[0091] The memory 620 includes a non-transitory computer readable medium. The memory' 620 includes a random-access memory (RAM), a read only memory (ROM), and / or another ty pe of dynamic or static storage device (e.g., a flash memory', a magnetic memory', and / or an optical memory) that stores information and / or instructions for use by' processor 610. The memory 620 comprises machine-readable instructions which are executable by the processor 610. These machine-readable instructions when executed by' the processor 610 cause the processor 610 to perform one or more method steps of an embodiment described in the present disclosure.

[0094]

[0092] The storage component 630 stores information and / or software related to the operation and use of the apparatus 600. For example, the storage component 630 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optic disk, and / or a solid-state disk), a compact disc (CD), a digital versatile disc (DVD), a floppy disk, a cartridge, a magnetic tape, and / or another type of non-transitory computer-readable medium, along with a corresponding drive.

[0095]

[0093] The input component 640 is configured to receive information, such as user input. For example, the input component 640 may include, but not be limited to, a touch screen display, a keyboard, a keypad, a mouse, a button, a switch, and / or a microphone. Additionally, or alternatively, the input component 640 may include a sensor for sensing information (e.g., a global positioning system (GPS), an accelerometer, a gyroscope, and / or an actuator).

[0094] The output component 650 is configured to provide output information from the apparatus 600. For example, the output component 650 may be, but not limited to, a display, a speaker, an instruction device to an external device, and / or one or more light-emitting diodes (LEDs).

[0096]

[0095] The communication interface 660 is an interface that provides a communication connection to other devices, such as external devices and internal devices. The connection by the communication interface 660 can be a wired connection, a wireless connection, or a combination of wired and wireless connections, and can be a direct connection or an indirect connection via a communication network that exists between the apparatus 600 and other devices. In other words, the standard of the communication interface 660 is not limited.

[0097]

[0096] The bus 670 acts as an interconnect between the processor 610, the memory' 620, the storage component 630, the input component 640, the output component 650, and the communication interface 660 of the apparatus 600. The bus 670 may include a wired interconnection or a wireless interconnection.

[0098]

[0097] The number and arrangement of components shown in FIG. 6 are provided as an example. In practice, the apparatus 600 may include additional components, fewer components, different components, or differently arranged components than those shown in FIG. 6. Additionally, or alternatively, a set of components (e.g., one or more components) of the apparatus 600 may perform one or more functions described as being performed by another set of components of the apparatus 600. Further, one or more method steps described in any of the embodiments may be performed utilizing a plurality of apparatuses 600 in communication with one another.

[0099]

[0098] In one non-limiting embodiment, the apparatus 600 may be used to implement some or all functions of any entity including UEs, various network entities of the RAN, various entities of the core network, but not limited thereto. Specifically, the apparatus 600 may implement the functionalities of the gNBs 102, 104, and the UEs 110.

[0100]

[0099] Referring now to FIG. 7, a flowchart is described illustrating an example method 700 performed by the gNB 102 for offloading one or more UEs 110 from the anchor cell 106 to the NES cells 108, according to an embodiment of the present disclosure. The operations of the gNB 102 may be implemented with the help of the apparatus 600 (and particularly, with the help of the at least one processor 610).

[0101]

[0100] The method 700 may include, at block 702, offloading one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell 108 of one or more NES cells 108 having overlapping coverage with an anchor cell 106, upon detecting that a current load of the one or more IDLE / INACTIVE UEs experienced by the anchor cell 106 (or Cell A) served by a base station 102 exceeds a threshold value. At block 704, the method 700 may include offloading the one or more IDLE / INACTIVE UEs to the at least one NES cell 108 by transmitting a SystemlnfoModification paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells 108 for performing cell re-selection to the at least one NES cell 108.

[0102]

[0101] At block 706, the method 700 may include offloading the one or more IDLE / INACTIVE UEs to the at least one NES cell 108 by transmitting a backhaul signaling message to at least one gNB 104 serving the at least one NES cell 108, instructing the at least one gNB 104 to initiate OD-SIB1 transmission for performing cell re-selection of the one or more IDLE / INACTIVE UEs to the at least one NES cell 108.

[0103]

[0102] Embodiments:

[0104]

[0103] Embodiment 1. A method comprising: upon detecting that a current load of one or more IDLE / INACTIVE UEs experienced by an anchor cell (Cell A) served by a base station

[0105] (gNB) exceeds a threshold value, offloading the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell by performing one of: transmitting a System Information Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell; or transmitting a backhaul signaling message to at least one gNB serving the at least one NES cell, instructing the at least one gNB to initiate On-Demand System Information Block Type 1 (OD-SIB1) transmission for performing cell re-selection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

[0106]

[0104] Embodiment 2. The method of embodiment 1, wherein transmitting the SystemlnfoModification paging message instructing the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells comprises: modifying a System Information Block (SIB) to include Physical Cell Identities (PCIs) of the one or more NES cells having the overlapping coverage with the anchor cell; and transmitting the modified SIB instructing the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells.

[0107]

[0105] Embodiment 3. The method of embodiment 2, wherein the modified SIB is either SIB 1 or another SIB acquired by the one or more IDLE / INACTIVE UEs.

[0108]

[0106] Embodiment 4. The method of any of embodiments 1-3, wherein the anchor cell is configured to periodically transmit a System Information Block Type 1 (SIB 1 ), and wherein the one or more NES cells are configured to omit periodic transmission of the SIB 1 and instead perform the OD-SIB1 transmission.

[0109]

[0107] Embodiment 5. The method of any of embodiments 1-4, wherein the one or more

[0110] IDLE / INACTIVE UEs comprise one or more of: at least one UE which is in an idle state having no active Radio Resource Control (RRC) connection with the gNB. and at least one UE which is in an inactive state having an inactive RRC connection with the gNB, and wherein the gNB is configured to server one or more connected UEs having an active RRC connection with the gNB.

[0111]

[0108] Embodiment 6. The method of embodiment 5, further comprising: detecting that a UE of the one or more connected UEs is going to transition from a connected state to the idle or inactive state; and upon detecting transition of the UE from the connected state to the idle or inactive state, transmitting an RRC release message including Uplink Wake Up Signal (UL WUS) configuration for the UE to directly request OD-SIB1 transmission from at least one first NES cell of the one or more NES cells, wherein the UL WUS configuration includes Physical Cell Identities (PCIs) of the one or more first NES cells.

[0112]

[0109] Embodiment 7. The method of embodiment 5 or 6, further comprising: upon detecting that the current load experienced by the anchor cell exceeds the threshold value, performing handover of at least one connected UE of the one or more connected UEs by performing: modifying a System Information Block (SIB) to include Physical Cell Identities (PCIs) of the one or more NES cells; transmitting the modified SIB instructing the at least one connected UE to evaluate the radio conditions of the one or more NES cells; and performing a handover of the at least one connected state UE to at least one second NES cell of the one or more NES cells based on measurements of the radio conditions received from the at least one connected UE.

[0113] [HO] Embodiment 8. The method of embodiment 7, wherein the modified SIB is either SIB1 or another SIB acquired by the at least one connected UE.

[0114] [Hl] Embodiment 9. The method of any of embodiments 1-8, further comprising: determining the current load experienced by the anchor cell based at least on a number of the IDLE / INACTIVE UEs which are served by the anchor cell.

[0115]

[0112] Embodiment 10. The method of any of embodiments 1-9, wherein the SystemlnfoModification paging message includes information indicating reason of offloading to inform the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells and perform cell re-selection when a predefined Radio Resource Management (RRM) criteria is satisfied.

[0116]

[0113] Embodiment 11. An apparatus configured to: upon detecting that a current load of one or more IDLE / INACTIVE UEs experienced by an anchor cell (Cell A) served by a base station (gNB) exceeds a threshold value, offload the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell by performing one of: transmitting a System Information Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell; or transmitting a backhaul signaling message to at least one gNB serving the at least one NES cell, instructing the at least one gNB to initiate On-Demand System Information Block Type 1 (OD-SIB1) transmission for performing cell re-selection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

[0117]

[0114] Embodiment 12. The apparatus of embodiment 11, wherein to transmit the SystemlnfoModification paging message instructing the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells, the apparatus is configured to: modify a System Information Block (SIB) to include Physical Cell Identities (PCIs) of the one or more NES cells having the overlapping coverage with the anchor cell; and transmit the modified SIB instructing the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells.

[0118]

[0115] Embodiment 13. The apparatus of embodiment 12, wherein the modified SIB is either SIB1 or another SIB acquired by the one or more IDLE / INACTIVE UEs.

[0119]

[0116] Embodiment 14. The apparatus of any of embodiments 11-13, wherein the anchor cell is configured to periodically transmit a System Information Block Type 1 (SIB1). and wherein the one or more NES cells are configured to omit periodic transmission of the SIB1 and instead perform the OD-SIB1 transmission.

[0120]

[0117] Embodiment 15. The apparatus of any of embodiments 11-14, wherein the one or more IDLE / INACTIVE UEs comprise one or more of: at least one UE which is in an idle state having no active Radio Resource Control (RRC) connection with the gNB, and at least one UE which is in an inactive state having an inactive RRC connection with the gNB, and wherein the gNB is configured to server one or more connected UEs having an active RRC connection with the gNB.

[0121]

[0118] Embodiment 16. The apparatus of embodiment 15, wherein the apparatus is further configured to: detect that a UE of the one or more connected UEs is going to transition from a connected state to the idle or inactive state; and upon detecting transition of the UE from the connected state to the idle or inactive state, transmit an RRC release message including Uplink Wake Up Signal (UL WUS) configuration for the UE to directly request OD-SIB1 transmission from at least one first NES cell of the one or more NES cells, wherein the UL WUS configuration includes Physical Cell Identities (PCIs) of the one or more first NES cells.

[0122]

[0119] Embodiment 17. The apparatus of embodiment 15 or 16, wherein the apparatus is further configured to: upon detecting that the current load experienced by the anchor cell exceeds the threshold value, perform handover of at least one connected UE of the one or more connected UEs by performing: modifying a System Information Block (SIB) to include Physical Cell Identities (PCIs) of the one or more NES cells; transmitting the modified SIB instructing the at least one connected UE to evaluate the radio conditions of the one or more NES cells, wherein the modified SIB is either SIB1 or another SIB acquired by the at least one connected UE; and performing a handover of the at least one connected state UE to at least one second NES cell of the one or more NES cells based on measurements of the radio conditions received from the at least one connected UE.

[0120] Embodiment 18. The apparatus of any of embodiments 11-17, wherein the apparatus is further configured to: determine the current load experienced by the anchor cell based at least on a number of IDLE / INACTIVE UEs which are served by the anchor cell.

[0123]

[0121] Embodiment 19. The apparatus of any of embodiments 11-18, wherein the SystemlnfoModification paging message includes information indicating reason of offloading to inform the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells and perform cell re-selection when a predefined Radio Resource Management (RRM) criteria is satisfied.

[0124]

[0122] Embodiment 20. A non-transitoiy computer readable media storing one or more computer executable instructions which, when executed by an apparatus, cause the apparatus to: upon detecting that a current load of one or more IDLE / INACTIVE UEs experienced by an anchor cell (Cell A) served by a base station (gNB) exceeds a threshold value, offload the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell by performing one of: transmitting a System Information Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell; or transmitting a backhaul signaling message to at least one gNB serving the at least one NES cell, instructing the at least one gNB to initiate On-Demand System Information Block Type I (OD-SIB1) transmission for performing cell re-selection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

[0125]

[0123] In a non-limiting embodiment of the present disclosure, one or more non-transitoiy computer-readable media may be utilized for implementing the embodiments consistent with the present disclosure. A computer-readable media refers to any type of physical memory (such as the memory 620) on which information or data readable by a processor may be stored. Thus, a computer-readable media may store one or more instructions for execution by the apparatus or by the at least one processor 610, including instructions for causing the at least one processor 608 to perform steps or stages consistent with the embodiments described herein. Certain nonlimiting embodiments may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer readable media having instructions stored (and / or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein.

[0126]

[0124] It may be noted here that the subj ect matter of some or all embodiments described with reference to FIG. 1-5 may be relevant for the method 700 and the same is not repeated for the sake of brevity. The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the disclosure be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present disclosure are intended to be illustrative, but not limiting, of the scope of the disclosure, which is set forth in the appended claims.

[0127] Additional Description:

[0128]

[0125] 1. Introduction

[0129] The Rel-19 WI on enhancements of network energy savings for NR (RP-234065) includes the objective to study on-demand SIB1 for idle / inactive UEs as mentioned below:

[0130] Study procedures and signaling method(s) to support on-demand SIB1 for UEs in idle / inactive mode, including: [RAN 1 / 2 / 3]

[0131] • Triggering method by uplink wake-up-signal using an existing signal / channel.

[0132] Wake-up-signal configuration provisioning to UE o Note: No modification of SSB will be discussed under this objective • Information exchange between gNBs at least for the configuration of wake-up signal, if necessary.

[0133] • Checkpoint for normative work in RAN# 105

[0134] The present disclosure discusses some important aspects associated with OD-SIB1, focussed on the highlighted objective.

[0135]

[0126] 2. Discussion

[0136] In this disclosure, the following nomenclature is referred.

[0137] The gNB associated with the NES cell as NES cell gNB

[0138] The gNB-CU associated with the NES cell as NES cell gNB-CU

[0139] The gNB-DU associated wi th the NES cell as NES cell gNB-DU

[0140] The gNB associated with the Cell A as Cell A gNB

[0141] The gNB-CU associated with the Cell A as Cell A gNB-CU

[0142] The gNB-DU associated with the Cell A as Cell A gNB-DU

[0143]

[0127] 2.1 Introduction

[0144] RAN1#116 (February 2024) made the following assumptions for the purpose of discussion:

[0145] For discussion purpose, the following assumption will be used in RANI

[0146] • Cell A: A cell that is periodically transmitting at least its own SIB1.

[0147] • NES Cell: A cell that may transmit SIB1 transmission in response to UL WUS from a UE

[0148] The cell A in the below example is a macro cell and the NES cell is a small cell which has at least partial overlapping coverage with the macro cell.

[0149]

[0128] 2.2 IDLE / INACTIVE mode overload in Cell A

[0150] When an overload condition is detected in Cell A with respect to IDLE / INACTIVE mode UEs, a percentage of IDLE / INACTIVE UEs have to be offloaded to the NES cells. Further, all new UEs coming to Cell A have to be re-directed to the NES cells until the overload condition eases. When the IDLE / INACTIVE UEs overload condition is detected, the anchor cell gNB shall offload UEs to one or more NES cells having overlapping coverage with it, an exemplary topography of anchor cell with overlapping NES cell(s) is shown in FIG. 8 which illustrates an example topology 800 of NES Cell and Anchor cell for OD-SIB1.

[0151] Proposal 1: When an overload condition of IDLE / INACTIVE UEs is detected in Cell A, the Cell A gNB shall initiate offloading of IDLE / INACTIVE UEs to NES cells.

[0152] To execute this offloading, the Cell A modifies its SIB1 to include the list of NES cell IDs to which offloading is intended. In addition to this, the cause “Overload Based Offloading” may also be indicated, so that the UEs can transmit a UL WUS to the NES cell and perform cell- reselection to NES cell after acquiring UL WUS configuration. Cell A gNB sends a Paging with System Info Modification to all UEs camped on it to read SIB1 modification. This enables the UEs to read the modified Cell A SIB 1 and evaluate the radio condition of NES cell and perform cell re-selection to NES cell, if feasible. Alternatively, if the Cell A gNB wants to take proactive action to just prevent new incoming UEs, it could send a backhaul signaling to the NES cell gNB to initiate OD-SIB1 transmission, so that all the incoming UEs could directly camp on the NES cell without coming to Cell A.

[0153] Proposal 2: Dunng overload, Cell A gNB initiates a Paging message with System Info Modification to trigger camped UEs to read modified SIB1 and transmit UL WUS and perform cell re-selection to NES cell.

[0154] Proposal 3: The Paging message with modified SIB1 may include the list of NES Cell IDs selected for offloading UEs and the cause.

[0155] Proposal 4: Cell A gNB may request NES cell gNB to trigger OD-SIB1 transmission without a UL WUS. RAN2 asks RAN3 to discuss and agree a solution to handle this issue.

[0156]

[0129] 2.3 SIB1 reacquisition in an NES cell Once a UE in IDLE / IN ACTIVE mode camps on NES cell, it may have to re-acquire SIB1 for reasons mentioned below.

[0157] RRC TS 38.331 :

[0158] 5.2.2.2 SIB validity and need to (re)-acquire SIB

[0159] 5.2.2.2.1 SIB validity'

[0160] The UE shall apply the SI acquisition procedure as defined in clause 5.2.2.3 upon cell selection (e.g. upon power on), cell-reselection, return from out of coverage, after reconfiguration with sync completion, after entering the network from another RAT, upon receiving an indication that the system information has changed, upon receiving a PWS notification, upon receiving request (e.g., a positioning request) from upper layers; and whenever the UE does not have a valid version of a stored SIB or posSIB or a valid version of a requested SIB.

[0161] It is observed that UEs might need to reacquire SIB1 under certain circumstances as mentioned above.

[0162] Observation 1: UEs might need to reacquire SIB1 of an NES cell after having camped there.

[0163] If the NES cell is transmitting OD-SIB1, then it can be assumed that the UE can perform a SIB1 re-acquisition. In case the NES cell is in Energy saving mode i.e., there is no periodic SIB transmission or OD-SIB1 transmission is stopped, then the most straightforward solution for UEs to reacquire SIB1 is to perform cell reselection to cell A where it can reacquire NES Cell UL WUS configuration. Subsequently it sends UL WUS to NES cell i.e., performs RACH procedure and requests OD-SIB1 transmission from the NES cell. Thus it can re-acquire the latest SIB1. This is sub-optimal as the UE has to perform cell reselection to cell A all over again. It incurs additional UE power as well as signaling towards the network.

[0164] Observation 2: For a UE camped on NES cell, it is suboptimal to perform cell re-selection to Cell A to acquire UL WUS configuration of NES cell, request NES cell to transmit OD-SIB1 again and re-acquire SIB1 of NES cell. Instead, the UL WUS configuration of an NES cell could be considered to be valid until explicitly indicated. This implies that whenever the UL WUS configuration of an NES cell is modified when the NES cell is in ES mode, the NES cell initiates OD-SIB1 broadcast proactively (i.e., deactivates ES mode) and sends a Paging message w ith System Info Broadcast to IDLE / INACTIVE UEs camped on it. This triggers the camped UEs to acquire the UL WUS configuration from the NES cell itself. Further, the UEs may use the UL WUS to re-acquire SIB 1 whenever required.

[0165] Proposal 5: UL WUS configuration of a NES cell acquired by a UE is considered valid unless explicitly indicated to the UE.

[0166] Proposal 6: Whenever an NES cell is in non-ES mode, the NES cell broadcasts its own UL WUS configuration in its SIB1.

[0167] Proposal 7: Whenever there is a modification in the UL WUS configuration of the NES cell, the NES cell proactively initiates OD-SIB1 transmission and sends a Paging message with System Info Broadcast to all IDLE / INACTIVE UEs.

[0168]

[0130] 2.4 Synergizing OD-SIB1 transmission in an NES cell

[0169] OD-SIB1 transmission is based on UL wake-up signal directly sent to NES cell (or via Cell A) from individual UEs and there could be multiple UEs in the coverage area of an NES cell who are eligible to camp on the NES cell, waiting for OD-S1B1 transmission.

[0170] NES cell triggering OD-SIB1 transmission per UE is sub-optimal from energy savings perspective. Moreover, the other eligible UEs in IDLE / INACTIVE mode are not aware of OD- SIB 1 transmission, as they may not try to perform cell re-selection at the same time.

[0171] Observation 3: NES cell triggering OD-SIB1 transmission per UE is sub-optimal from energy savings perspective.

[0172] Observation 4: Eligible UEs in IDLE / INACTIVE mode which are camped on Cell A are not aware of NES cell's OD-SIB1 transmission. To mitigate this, the NES cell may decide when to start the OD-SIB1 transmission. For example, the gNB could configure a threshold number of “n” UEs requesting OD-SIB1, before initiating OD-SIB1 transmission, i.e., the OD-SIB1 transmission could be initiated only after ‘n’ UEs have sent UL wake-up signal to the NES cell.

[0173] In such a case where the NES is not going to start the OD-SIB1 transmission immediately upon receiving the UL WUS, the gNB may indicate to the UE, for example in the Random Access Response(RAR), that the UE need not monitor PDCCH in the RAR-window. The UE may also implicitly understand that the network will communicate whenever OD-SIB1 transmission is initiated.

[0174] Proposal 8: gNB shall be able to be configured to wait until a threshold number of “n” UEs request OD-SIB1 before initiating OD-SIB1 transmission in an NES cell.

[0175] Proposal 9: Post receiving a UL WUS request, the gNB shall be able to indicate to the UE to not monitor PDCCH in the RAR-window, when the OD-SIB 1 transmission is not initiated immediately.

[0176] Subsequently, when the ‘n’ number of UL WUS requests are received, the gNB may initiate the OD-SIB1 transmission at the NES cell. Since the intention is to inform all the eligible UEs (including those that have already sent a UL WUS requesting OD-SIB1 earlier), the NES cell gNB has to notify the cell A gNB to notify the IDLE / lNACTfVE UEs camped on cell A, so that they can access the OD-SIB1 transmission.

[0177] Proposal 10: The NES cell gNB shall notify the Cell A gNB about the NES Cell ID and its OD-SIB1 transmission. RAN2 asks RAN3 to discuss and agree a way forward for this issue. Proposal 11: The Cell A gNB shall send a Paging message to all the IDLE / INACTIVE UEs to inform them about the NES Cell ID and its OD-SIB 1 transmission. Proposal 12: The IDLE / INACTIVE UEs on Cell A, who already have the WUS configuration of the given NES cell, may access OD-SIB1 of NES cell and perform cell re-selection to NES cell.

[0178]

[0131] 3. Conclusion

[0179] In summary. following are observations:

[0180] Observation 1 UEs might need to reacquire SIB1 of an NES cell after having camped there.

[0181] Observation 2 For a UE camped on NES cell, it is suboptimal to perform cell re-selection to Cell A to acquire UL WUS configuration of NES cell, request NES cell to transmit OD-SIB1 again and re-acquire SIB1 of NES cell.

[0182] Observation 3 NES cell triggering OD-SIB1 transmission per UE is sub-optimal from energy savings perspective.

[0183] Observation 4 Eligible UEs in IDLE / INACTIVE mode which are camped on Cell A are not aware of NES cell’s OD-SIB1 transmission.

[0184] In summaiy, following are the proposals:

[0185] Proposal 1 When an overload condition of IDLE / INACTIVE UEs is detected in Cell A, the

[0186] Cell A gNB shall initiate offloading of IDLE / INACTIVE UEs to NES cells.

[0187] Proposal 2 During overload. Cell A gNB initiates a Paging message with System Info Modification to trigger camped UEs to read modified S1B1 and transmit UL WUS and perform cell re-selection to NES cell.

[0188] Proposal 3 The Paging message with modified SIB1 may include the list of NES Cell IDs selected for offloading UEs and the cause.

[0189] Proposal 4 Cell A gNB may request NES cell gNB to trigger OD-SIB1 transmission without a UL WUS. RAN2 asks RAN3 to discuss and agree a solution to handle this issue.

[0190] Proposal 5 UL WUS configuration of an NES cell acquired by a UE is considered valid unless explicitly indicated to the UE. Proposal 6 Whenever an NES cell is in non-ES mode, the NES cell broadcasts its own UL WUS configuration in its SIB1.

[0191] Proposal 7 Whenever there is a modification in the UL WUS configuration of the NES cell, the NES cell proactively initiates OD-SIB1 transmission and sends a Paging message with System Info Broadcast to all IDLE / INACTIVE UEs.

[0192] Proposal 8 gNB shall be able to be configured to wait until a threshold number of “n” UEs request OD-SIB1 before initiating OD-SIB1 transmission in an NES cell.

[0193] Proposal 9 Post receiving a UL WUS request, the gNB shall be able to indicate to the UE to not monitor PDCCH in the RAR- window, when the OD-SIB1 transmission is not initiated immediately.

[0194] Proposal 10 The NES cell gNB shall notify the Cell A gNB about the NES Cell ID and its OD-SIB1 transmission. RAN2 asks RAN3 to discuss and agree a way forw ard for this issue.

[0195] Proposal 1 1 The Cell A gNB shall send a Paging message to all the IDLE / INACTIVE UEs to inform them about the NES Cell ID and its OD-SIB1 transmission.

[0196] Proposal 12 The IDLE / INACTIVE UEs on Cell A, who already have the WUS configuration of the given NES cell, may access OD-SIB1 of NES cell and perform cell reselection to NES cell.

Claims

1. WE CLAIM1. A method comprising: upon detecting that a current load of one or more IDLE / INACTIVE User Equipment (UEs) experienced by an anchor cell (Cell A) served by a base station (gNB) exceeds a threshold value, offloading the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell by performing one of: transmitting a System Information Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell; or transmitting a backhaul signaling message to at least one other gNB serving the at least one NES cell, instructing the at least one other gNB to initiate On-Demand System Information Block Type 1 (OD-SIB1) transmission for performing cell reselection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

2. The method as claimed in claim 1, wherein transmitting the SystemlnfoModification paging message instructing the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells comprises: modifying a System Information Block (SIB) to include Physical Cell Identities (PCIs) of the one or more NES cells having the overlapping coverage with the anchor cell; and transmitting the modified SIB instructing the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells.

3. The method as claimed in claim 2, wherein the modified SIB is either SIB1 or anotherSIB acquired by the one or more IDLE / INACTIVE UEs.

4. The method as claimed in claim 1, wherein the anchor cell is configured to periodically transmit a System Information Block Type 1 (SIB1), and wherein the one or more NES cells are configured to omit periodic transmission of the SIB1 and instead perform the OD-SIB1 transmission.

5. The method as claimed in claim 1, wherein the one or more IDLE / INACTIVE UEs comprise one or more of: at least one UE which is in an idle state having no active Radio Resource Control (RRC) connection with the gNB, and at least one UE which is in an inactive state having an inactive RRC connection with the gNB, and wherein the gNB is configured to server one or more connected UEs having an active RRC connection with the gNB.

6. The method as claimed in claim 5, further comprising: detecting that a UE of the one or more connected UEs is going to transition from a connected state to the idle or inactive state; and upon detecting transition of the UE from the connected state to the idle or inactive state, transmitting an RRC release message including Uplink Wake Up Signal (UL WUS) configuration for the UE to directly request OD-SIB1 transmission from at least one first NES cell of the one or more NES cells, wherein the UL WUS configuration includes Physical Cell Identities (PCIs) of the one or more first NES cells.

7. The method as claimed in claim 5, further comprising:upon detecting that the current load experienced by the anchor cell exceeds the threshold value, perfonning handover of at least one connected UE of the one or more connected UEs by perfonning: modifying a System Information Block (SIB) to include Physical Cell Identities (PCIs) of the one or more NES cells; transmitting the modified SIB instructing the at least one connected UE to evaluate the radio conditions of the one or more NES cells; and performing a handover of the at least one connected state UE to at least one second NES cell of the one or more NES cells based on measurements of the radio conditions received from the at least one connected UE.

8. The method as claimed in claim 7, wherein the modified SIB is either SIB1 or another SIB acquired by the at least one connected UE.

9. The method as claimed in claim 1, further comprising: determining the current load experienced by the anchor cell based at least on a number of the IDLE / INACTIVE UEs which are served by the anchor cell.

10. The method as claimed in claim 1, wherein the SystemlnfoModifi cation paging message includes information indicating reason of offloading to inform the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells and perform cell re-selection when a predefined Radio Resource Management (RRM) criteria is satisfied.

11. An apparatus configured to:upon detecting that a current load of one or more IDLE / INACTIVE User Equipment (UEs) experienced by an anchor cell (Cell A) served by a base station (gNB) exceeds a threshold value, offload the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell by performing one of: transmitting a System Information Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell; or transmitting a backhaul signaling message to at least one other gNB serving the at least one NES cell, instructing the at least one other gNB to initiate On -Demand System Information Block Type 1 (OD-SIB1) transmission for performing cell reselection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

12. The apparatus as claimed in claim 11, wherein to transmit the SystemlnfoModification paging message instructing the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells, the apparatus is configured to: modify a System Information Block (SIB) to include Physical Cell Identities (PCIs) of the one or more NES cells having the overlapping coverage with the anchor cell; and transmit the modified SIB instructing the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells.

13. The apparatus as claimed in claim 12, wherein the modified SIB is either SIB1 or another SIB acquired by the one or more IDLE / INACTIVE UEs.

14. The apparatus as claimed in claim 11, wherein the anchor cell is configured to periodically transmit a System Information Block Type 1 (SIB1), and wherein the one or more NES cells are configured to omit periodic transmission of the SIB1 and instead perform the OD-SIB1 transmission.

15. The apparatus as claimed in claim 11, wherein the one or more IDLE / INACTIVE UEs comprise one or more of at least one UE which is in an idle state having no active Radio Resource Control (RRC) connection with the gNB, and at least one UE which is in an inactive state having an inactive RRC connection with the gNB, and wherein the gNB is configured to server one or more connected UEs having an active RRC connection with the gNB.

16. The apparatus as claimed in claim 15, wherein the apparatus is further configured to: detect that a UE of the one or more connected UEs is going to transition from a connected state to the idle or inactive state; and upon detecting transition of the UE from the connected state to the idle or inactive state, transmit an RRC release message including Uplink Wake Up Signal (UL WUS) configuration for the UE to directly request OD-SIB1 transmission from at least one first NES cell of the one or more NES cells, wherein the UL WUS configuration includes Physical Cell Identities (PCls) of the one or more first NES cells.

17. The apparatus as claimed in claim 15, wherein the apparatus is further configured to: upon detecting that the current load experienced by the anchor cell exceeds the threshold value, perfonn handover of at least one connected UE of the one or more connectedUEs by performing:modifying a System Information Block (SIB) to include Physical Cell Identities(PCIs) of the one or more NES cells; transmitting the modified SIB instructing the at least one connected UE to evaluate the radio conditions of the one or more NES cells, wherein the modified SIB is either SIB 1 or another SIB acquired by the at least one connected UE; and performing a handover of the at least one connected state UE to at least one second NES cell of the one or more NES cells based on measurements of the radio conditions received from the at least one connected UE.

18. The apparatus as claimed in claim 11, wherein the apparatus is further configured to: determine the current load experienced by the anchor cell based at least on a number of the IDLE / INACTIVE UEs which are served by the anchor cell.

19. The apparatus as claimed in claim 11, wherein the SystemlnfoModification paging message includes information indicating reason of offloading to inform the one or more IDLE / INACTIVE UEs to evaluate the radio conditions of the one or more NES cells and perform cell re-selection when a predefined Radio Resource Management (RRM) criteria is satisfied.

20. A non-transitory computer readable media storing one or more computer executable instructions which, when executed by an apparatus, cause the apparatus to: upon detecting that a current load of one or more IDLE / INACTIVE UEs experienced by an anchor cell (Cell A) served by a base station (gNB) exceeds a threshold value, offload the one or more IDLE / INACTIVE UEs to at least one Network Energy Saving (NES) cell of one or more NES cells having overlapping coverage with the anchor cell by performing one of:transmitting a System Infonnation Modification (SystemlnfoModification) paging message instructing the one or more IDLE / INACTIVE UEs to evaluate radio conditions of the one or more NES cells for performing cell re-selection to the at least one NES cell; or transmitting a backhaul signaling message to at least one other gNB serving the at least one NES cell, instructing the at least one other gNB to initiate On-Demand System Information Block Type 1 (OD-SIB1) transmission for performing cell reselection of the one or more IDLE / INACTIVE UEs to the at least one NES cell.

Images