WO2021232239A1

WO2021232239A1 - Radio resource control inactive state for remote user equipment

Info

Publication number: WO2021232239A1
Application number: PCT/CN2020/091052
Authority: WO
Inventors: Xiang Xu; Ling Yu; Vinh Van Phan
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2020-05-19
Filing date: 2020-05-19
Publication date: 2021-11-25
Also published as: CN114026953A; CN114026953B

Abstract

Systems, methods, apparatuses, and computer program products for facilitating fast and efficient radio resource control (RRC) connection and protocol data unit (PDU) session setup for a remote-UE are provided. One method may include determining, by a core network node, that an establishment or modification of a radio resource control (RRC) inactive context for a remote user equipment is to be initiated, where the remote user equipment is in out-of-coverage, in RRC idle state, or in RRC inactive state of a radio access network. The method may also include initiating to a selected network node an establishment request or a modification request on the radio resource control (RRC) inactive context for the remote user equipment.

Description

RADIO RESOURCE CONTROL INACTIVE STATE FOR REMOTE USER EQUIPMENT

FIELD:

Some example embodiments may generally relate to mobile or wireless telecommunication systems, such as Long Term Evolution (LTE) or fifth generation (5G) radio access technology or new radio (NR) access technology, or other communications systems. For example, certain embodiments may relate to sidelink (SL) based user equipment (UE) -to-network (NW) relay.

BACKGROUND:

Examples of mobile or wireless telecommunication systems may include the Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) , Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN) , LTE-Advanced (LTE-A) , MulteFire, LTE-A Pro, and/or fifth generation (5G) radio access technology or new radio (NR) access technology. 5G wireless systems refer to the next generation (NG) of radio systems and network architecture. A 5G system is mostly built on a 5G new radio (NR) , but a 5G (or NG) network can also build on the E-UTRA radio. It is estimated that NR provides bitrates on the order of 10-20 Gbit/s or higher, and can support at least service categories such as enhanced mobile broadband (eMBB) and ultra-reliable low-latency-communication (URLLC) as well as massive machine type communication (mMTC) . NR is expected to deliver extreme broadband and ultra-robust, low latency connectivity and massive networking to support the Internet of Things (IoT) . With IoT and machine-to-machine (M2M) communication becoming more widespread, there will be a growing need for networks that meet the needs of lower power, low data rate, and long battery life. The next generation radio access network (NG-RAN) represents the RAN for 5G, which can provide both NR and LTE (and LTE-Advanced) radio accesses. It is noted that, in 5G, the nodes that can provide radio access functionality to a user equipment (i.e., similar to the Node B, NB, in UTRAN or the evolved NB, eNB, in LTE) may be named next-generation NB (gNB) when built on NR radio and may be named next-generation eNB (NG-eNB) when built on E-UTRA radio.

SUMMARY:

An embodiment is directed to an apparatus that may include at least one processor and at least one memory comprising computer program code. The at least one memory and computer program code configured, with the at least one processor, to cause the apparatus at least to determine that an establishment or modification of a radio resource control (RRC) inactive context for a remote user equipment is to be initiated. The remote user equipment may be in out-of-coverage, radio resource control (RRC) idle state, or radio resource control (RRC) inactive state of a radio access network. The at least one memory and computer program code may be further configured, with the at least one processor, to cause the apparatus at least to initiate to a selected network node an establishment request or a modification request on the radio resource control (RRC) inactive context for the remote user equipment.

Another embodiment may be directed to a method that may include determining, by a core network node, that an establishment or modification of a radio resource control (RRC) inactive context for a remote user equipment is to be initiated. The remote user equipment may be in out-of-coverage, radio resource control (RRC) idle state, or radio resource control (RRC) inactive state of a radio access network. The method may also include initiating to a selected network node an establishment request or a modification request on the radio resource control (RRC) inactive context for the remote user equipment.

In an embodiment, the method may also include receiving, from the selected network node, the established or modified radio resource control (RRC) inactive context for the remote user equipment, and updating the established or modified radio resource control (RRC) inactive context and related configurations for the remote user equipment.

In an embodiment, the method may also include requesting the remote user equipment to transition into radio resource control (RRC) connected to a selected network node for a state transition to radio resource control (RRC) inactive state.

In an embodiment, the determining that the establishment or modification of the radio resource control (RRC) inactive context for the remote user equipment is to be initiated may be based on at least one of: a need to provide a certain service continuity and/or power efficiency for the remote user equipment; or a received request, indication, or report from the remote user equipment, or from the relay user equipment, or from a serving network node of the relay user equipment, or from a serving network function (NF) of the relay user equipment or the remote user equipment.

In an embodiment, the method may include receiving, from the remote user equipment or from the relay user equipment, a report on neighboring cell measurements.

In an embodiment, the method may include receiving, from the remote user equipment, an indication of user equipment capability, and informing the selected network node of the user equipment capability of the remote user equipment.

In an embodiment, the method may also include receiving a suspend configuration parameter, wherein the suspend configuration parameter comprises a list of relay user equipment, transmitting the suspend configuration parameter to the relay user equipment for forwarding to the remote user equipment, and providing the remote user equipment with a time gap over PC5 interface to perform the state transition to radio resource control (RRC) inactive state.

In an embodiment, the selected network node is the same or different from a network node serving the relay user equipment. In one embodiment, the selected network node may be selected based on a report received from one of the remote user equipment, the relay user equipment or a serving network node of the relay user equipment.

In an embodiment, when requesting of the remote user equipment to transition into radio resource control (RRC) connected to the selected network node for the state transition to radio resource control (RRC) inactive state, the method may include transmitting a paging message indicating that paging is related to PC5 to setup the INACTIVE state for the remote user equipment.

Another embodiment is directed to an apparatus that may include at least one processor and at least one memory comprising computer program code. The at least one memory and computer program code configured, with the at least one processor, to cause the apparatus at least to transmit a measurement report to a relay user equipment, where the apparatus is in out-of-coverage (OoC) or radio resource control (RRC) idle state and is connected to a core network via the relay user equipment, to receive a request to transition into radio resource control (RRC) inactive state, and to transition from the out-of-coverage (OoC) or radio resource control (RRC) idle state to the radio resource control (RRC) inactive state.

Another embodiment is directed to a method that may include transmitting, by a remote user equipment, a measurement report to a relay user equipment. The remote user equipment may be in out-of-coverage (OoC) or radio resource control (RRC) idle state and is connected to a core network via the relay user equipment. The method may also include receiving a request to transition into radio resource control (RRC) inactive state, and transitioning, by the remote user equipment, from the out-of-coverage (OoC) or radio resource control (RRC) idle state to the radio resource control (RRC) inactive state.

In an embodiment, the request may include a request to transition into radio resource control (RRC) connected state to a selected network node for the state transition to the radio resource control (RRC) inactive state.

In an embodiment, the measurement report may include at least one of: information on neighbouring cells, or information on preferred network node, or an indication that the apparatus seeks to use the radio resource control (RRC) inactive state.

In an embodiment, the method may also include indicating a user equipment capability to the core network. In an embodiment, the method may include receiving the request for transition to the radio resource control (RRC) inactive state from the relay user equipment, or from the selected network node. According to one embodiment, the request may include at least a suspend configuration parameter.

In an embodiment, the method may include indicating, to the selected network node, a new cause of radio resource control (RRC) inactive state transition for requesting radio resource control (RRC) connection establishment.

In an embodiment, the method may include receiving a time gap over PC5 interface to perform the state transition to radio resource control (RRC) inactive state.

Another embodiment may be directed to an apparatus including at least one processor and at least one memory comprising computer program code. The at least one memory and computer program code configured, with the at least one processor, to cause the apparatus at least to receive a request to transition a remote user equipment from out-of-coverage (OoC) or radio resource control (RRC) idle state to radio resource control (RRC) inactive state, and to provide at least one suspend configuration parameter to the core network or to the remote user equipment.

Another embodiment is directed to a method that may include receiving, at a network node, a request to transition a remote user equipment from out-of-coverage (OoC) or radio resource control (RRC) idle state to radio resource control (RRC) inactive state, and providing at least one suspend configuration parameter to the core network or to the remote user equipment.

In an embodiment, the providing of the at least one suspend configuration parameter to the remote user equipment is triggered based on receiving a radio resource control (RRC) establishment request with an indication from the remote user equipment, and/or a request from the core network.

Another embodiment is directed to an apparatus that may include means for determining that an establishment or modification of a radio resource control (RRC) inactive context for a remote user equipment is to be initiated, where the remote user equipment is in out-of-coverage, radio resource control (RRC) idle state, or radio resource control (RRC) inactive state of a radio access network. The apparatus may also include means for imitating to a selected network node an establishment request or a modification request on the radio resource control (RRC) inactive context for the remote user equipment.

Another embodiment is directed to an apparatus that may include means for transmitting a measurement report to a relay user equipment, where the apparatus is in out-of-coverage (OoC) or radio resource control (RRC) idle state and is connected to a core network via the relay user equipment. The apparatus may also include means for receiving a request to transition into radio resource control (RRC) inactive state, and means for transitioning from the out-of-coverage (OoC) or radio resource control (RRC) idle state to the radio resource control (RRC) inactive state.

Another embodiment is directed to an apparatus that may include means for receiving a request to transition a remote user equipment from out-of-coverage (OoC) or radio resource control (RRC) idle state to radio resource control (RRC) inactive state, and means for providing at least one suspend configuration parameter to the core network or to the remote user equipment.

BRIEF DESCRIPTION OF THE DRAWINGS:

For proper understanding of example embodiments, reference should be made to the accompanying drawings, wherein:

Fig. 1 illustrates an example of the protocol stack for LTE UE-to-Network relay;

Fig. 2 illustrates an example signaling diagram depicting UE triggered transition from RRC inactive state to RRC connected state, according to one example;

Fig. 3 illustrates an example diagram of UE state machine and state transitions between NR/5GC, E-UTRA/EPC and E-UTRA/5GC, according to one example;

Fig. 4 illustrates an example of the new state transitions for a remote-UE, according to certain embodiments;

Fig. 5 illustrates an example signaling diagram, according to an embodiment;

Fig. 6 illustrates an example of RAN notification area information IE, according to one embodiment;

Fig. 7a illustrates an example signaling diagram, according to an embodiment;

Fig. 7b illustrates an example signaling diagram, according to an embodiment;

Fig. 8a illustrates an example flow diagram of a method, according to an embodiment;

Fig. 8b illustrates an example flow diagram of a method, according to an embodiment;

Fig. 8c illustrates an example flow diagram of a method, according to an embodiment;

Fig. 9a illustrates an example block diagram of an apparatus, according to an embodiment; and

Fig. 9b illustrates an example block diagram of an apparatus, according to an embodiment.

DETAILED DESCRIPTION:

It will be readily understood that the components of certain example embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description provides some example embodiments of systems, methods, apparatuses, and computer program products for facilitating fast and efficient radio resource control (RRC) connection and protocol data unit (PDU) session setup for a remote-UE. The examples discussed herein are not intended to limit the scope of certain embodiments but is representative of some selected example embodiments.

The features, structures, or characteristics of example embodiments described throughout this specification may be combined in any suitable manner in one or more example embodiments. For example, the usage of the phrases “certain embodiments, ” “some embodiments, ” or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment. Thus, appearances of the phrases “in certain embodiments, ” “in some embodiments, ” “in other embodiments, ” or other similar language, throughout this specification do not necessarily all refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments.

Additionally, if desired, the different functions or procedures discussed below may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the described functions or procedures may be optional or may be combined. As such, the following description should be considered as illustrative of the principles and teachings of certain example embodiments, and not in limitation thereof.

An embodiment may relate to the SL based UE-to-NW relay, for example, as targeted for 3GPP Release-17 and beyond. Fig. 1 illustrates an example of the protocol stack for LTE UE-to-Network Relay. If layer 3 (L3) relay is adopted for NR, the protocol stack may be similar to that of Fig. 1.

The PC5 interface between the UE (i.e., remote-UE as described herein) and relay (i.e., relay-UE as described herein) can be based on 3GPP radio access technology (RAT) , e.g., 4G or 5G, or non-3GPP RAT (e.g., WLAN, Bluetooth) . One reason to use L3 Relay instead of L2 Relay is to minimize the impact to the RAN node and Uu interface. In current L3 relay, the remote-UE’s traffic is sent via the relay-UE’s packet data network (PDN) connection (for LTE) and PDU session (for 5G) . The remote-UE is invisible to the RAN node. There is no RRC message transmitted between the remote-UE and the RAN node via the relay-UE.

Fig. 2 illustrates an example signaling diagram depicting UE triggered transition from RRC INACTIVE state to RRC CONNECTED state. RRC INACTIVE is a state where a UE remains in a connection management (CM) CONNECTED state and can move within an area configured by NG-RAN (the RAN based notification area (RNA) ) without notifying NG-RAN. The UE is kept “always on” from the 5G core side, but the RRC connection between the UE and RAN can be suspended and resumed upon request. In RRC INACTIVE state, the last serving gNB node keeps the UE context and the UE-associated NG connection with the serving access and mobility management function (AMF) and user plane function (UPF) .

The suspension of the RRC connection may be initiated by the RAN node. When the RRC connection is suspended, the UE may store the UE inactive access stratum (AS) context and possibly a configuration received from the network, and transits to RRC_INACTIVE state.

The resumption of a suspended RRC connection is initiated by upper layers when the UE wants to transit from RRC_INACTIVE state to RRC_CONNECTED state or by RRC layer to perform a RNA update or by RAN paging from the RAN node. The RRC_INACTIVE state enables the UE to quickly resume the PDU session, when there is a need for uplink (UL) or downlink (DL) data transmission for the UE.

In current L3 UE-to-Network Relay (i.e., L3 Relay) , the serving RAN node (e.g., gNB) is unaware of the remote-UE (s) being connected to the relay-UE. The L3 relay specified in LTE is limited to public-safety uses. The remote-UE is considered being in either out-of-coverage (OoC) or in partial coverage of the serving RAN. Thus, the remote-UE may be in RRC_IDLE of a serving E-UTRAN while being served by the relay-UE in RRC_CONNECTED of the same or different serving E-UTRAN. There is no dedicated control plane (C-plane) or user plane (U-plane) connection provided by the serving network of the relay-UE for the remote-UE. Furthermore, no service continuity is provided for the remote-UE in LTE. It is noted that support for OoC operation of a UE may be for public-safety purposes (including road safety for V2X) , but not for commercial uses in general. For commercial uses, a UE is expected to be in coverage of a serving network and provided with both C-plane and U-plane connections. The service continuity is also expected at least to some extent for commercial UE. Thus, for supporting both public-safety and commercial use cases in 5GS or NR networks with the L3 Relay, the remote-UE connected to the serving network via the relay-UE is expected to be kept in the CM_CONNECTED state of the serving CN but transparent to RAN. That is, it can be assumed that the remote-UE may be in OoC or RRC_IDLE state of the serving RAN while being connected to the serving CN using the L3 relay via the relay-UE.

Presently, there is no support for service continuity in the current L3 relay. That is, a possible mode switch or handover between using L3 relay via PC5 and direct access via Uu for the remote-UE has not been supported in 3GPP standards. However, as the remote-UE is in RRC_IDLE or OoC of the serving RAN, the remote-UE may need to perform a full connection setup over Uu (including cell selection or reselection, initial access, RRC connection and PDU session setup) in order to obtain direct access to the serving network. This may not be preferable in terms of latency and protocol overhead for a support of service continuity or QoS enhancement upon a failure of the relayed connection for the remote-UE, for example.

It is noted that the above issue also concerns UE (s) accessing the serving network using an access point with non-3GPP RAT (such as WiFi) and not the serving RAN with 3GPP RAT. Thus, the remote-UE discussed herein may include such UE (s) as well.

Certain embodiments described herein can enable and facilitate fast and efficient RRC connection and PDU session setup for a remote-UE when the remote-UE has a need to return to the direct network access, e.g., using Uu from the current network access using L3 relay with 3GPP RAT or using an access point with non-3GPP RAT.

Fig. 3 illustrates an example diagram of UE state machine and state transitions between NR/5GC, E-UTRA/EPC and E-UTRA/5GC. In current NR networks, UE in coverage of a serving RAN may be in either RRC_IDLE, RRC_INACTIVE or RRC_CONNECTED state of the serving RAN. As illustrated in the example of Fig. 3, the state transition directly from RRC_IDLE to RRC_INACTIVE or from OoC to RRC_INACTIVE is not supported. In RRC-IDLE, the RAN does not have any context for the UE and, as a result, transition from IDLE state to INACTIVE state is not possible.

Certain embodiments may be based on utilizing the RRC_INACTIVE state and the fast resume from the RRC_INACTIVE state for the remote-UE as on-demand, in order to enable a fast connection setup over Uu when the remote-UE has a need to return to the direct network access via the serving gNB from the current network access using L3 Relay with 3GPP RAT or using an access point with non-3GPP RAT. Hence, an embodiment provides a method to enable and facilitate a proactive core network (CN) (e.g., AMF) initiated establishment or modification of RRC_INACTIVE context for the remote-UE which is currently in OoC or RRC_IDLE and using the L3 relay with 3GPP RAT or using an access point with non-3GPP RAT to obtain access to the serving network. This may cause a state transition from OoC or RRC_IDLE to RRC_INACTIVE for the remote-UE, either directly or indirectly via RRC_CONNECTED (i.e., with or without having the remote-UE transition into RRC_CONNECTED from RRC_IDLE for the state transition to RRC_INACTIVE, considering the impact on standards versus efficiency or signalling overhead) .

Fig. 4 illustrates an example of the new state transitions 101, 102, 103 for a remote-UE, according to certain example embodiments. For example, transition 101 may provide the state transition from OoC to RRC_INACTIVE, transition 102 may provide the state transition from RRC_IDLE to RRC_INACTIVE, and transition 103 may provide the state transition from RRC_IDLE to RRC_INACTIVE via RRC_CONNECTED state.

In the following, some example embodiments will be described in view of the serving CN node or AMF of the remote-UE, for instance. According to certain embodiments, the serving CN node or AMF of the remote-UE may perform the following procedures in any suitable order. In one embodiment, the CN node or AMF may determine a need to initiate an establishment or modification of RRC_INACTIVE context for the remote-UE while the remote-UE is being served using the L3 relay with 3GPP RAT or using an access point with non-3GPP RAT. This may be considered as a proactive action that may be based, for example, on: a need to provide a certain service continuity and/or power efficiency for the remote-UE as defined in the subscription or service profile of the remote-UE; a received request/indication/report from the remote-UE, from the relay-UE, the serving gNB of the relay-UE, or network functions (NFs) of the relay-UE or the remote-UE on, e.g., network connections, service flows, QoS, measurements (statuses or conditions) of either the relay-UE or the remote-UE, as well as the serving gNB or NFs of either the relay-UE or the remote-UE; or any other appropriate situation, etc.

In an embodiment, the CN node or AMF may perform at least one of the options discussed in the following. In a first option (option 1) , which may be represented by the

direct lines

101, 102 from OoC and RRC_IDLE to RRC_INACTIVE in Fig. 4, the CN node or AMF may request a selected gNB to set up or modify RRC_INACTIVE UE context for the remote-UE. The selected gNB may be the same as or different from the serving gNB of the relay-UE. This selection of the gNB may be based, for example, on a provided neighbouring-cell list received from either the remote-UE, the relay-UE or the serving gNB of the relay-UE. The selected gNB may allow to select a different AMF for establishing or modifying RRC_INACTIVE UE context for the remote-UE.

In a second option (option 2) , which may be represented by the line 103 from RRC_IDLE via RRC_CONNECTED to RRC_INACTIVE in Fig. 4, the CN node or AMF may request the remote-UE to transition into RRC_CONNECTED to a selected gNB for a state transition to RRC_INACTIVE but not for a mode switch or handover (HO) . The selected gNB may be the same as or different from the serving gNB of the relay-UE. An indication of the selected gNB may be provided by the serving AMF in the request or left for the remote-UE to select within a given RAN-based notification area (RNA) .

According to an embodiment, the CN node or AMF may receive, from the selected gNB, the established or modified RRC_INACTIVE UE context for the remote-UE. In certain embodiments, the CN node or AMF may update the established or modified RRC_INACTIVE UE context as well as related configuration (triggers or rules for updating and using the RRC_INACTIVE UE context for examples) with the remote-UE while the remote-UE is being served using either the L3 relay with 3GPP RAT or an access point with non-3GPP RAT.

In one embodiment, a remote-UE may be configured to measure and report on, for example, inter-cell measurement to the serving AMF of the remote-UE. The remote-UE may also receive measurement-related configuration from the relay-UE, such as candidate neighbouring-cell list, time gap for performing measurement, etc.

According to one embodiment, a remote-UE may be configured to indicate UE capability to the serving AMF, which may be used for option 1 (the serving AMF may then inform the selected gNB of the UE capability of the remote-UE) , for example.

In one embodiment, a remote-UE in option 2 may indicate to the selected gNB a new cause of INACTIVE state transition for requesting RRC connection establishment. The remote-UE may further indicate L3 relay related context to the selected gNB.

According to an embodiment, a remote-UE in option 2 may be provided a time gap over PC5 to perform the requested state transition, from the relay-UE upon a request from either the remote-UE over PC or the serving gNB of the relay-UE over Uu or from the serving AMF of the remote-UE.

In one embodiment, there may be signalling transactions related to the state transition of the remote-UE to RRC_INACTIVE between the serving gNB of the relay-UE, the selected gNB of the remote-UE (which may be the same as or different from the serving gNB of the relay UE) , the serving AMF of the relay-UE and the serving AMF of the remote-UE (which may be the same as or different from the serving AMF of the relay-UE) .

Certain embodiments may be further extended for LTE L3 relay as well. In this case, as the relay-UE is fully in charge of admitting and serving the remote-UE, the remote-UE does not have either dedicated C-plane or U-plane connection to the serving CN of the relay-UE. However, the serving network, both CN and RAN, may be reported or informed of the remote-UE by the relay-UE. In this case, the serving network may be able to determine whether the remote-UE is allowed to have a direct access to the serving network of the relay-UE or not and, if allowed and possibly needed, the serving network of the relay-UE may initiate to set up INACTIVE UE context for the remote-UE via the relay-UE or by paging the remote-UE (provided that the remote-UE is in coverage of the serving 3GPP RAT coverage) .

Fig. 5 illustrates an example signaling diagram depicting an embodiment according to option 1. As illustrated in the example of Fig. 5, at 500, the remote-UE is RRC_IDLE, or the remote-UE is out of Uu coverage. The remote-UE is already connected to the CN via the relay-UE. At 501, the remote-UE may provide a measurement report to the relay-UE. The measurement report may be further forwarded to the CN node. The measurement may indicate the information of the neighboring gNB cells, either based on the remote-UE’s measurement when the remote-UE is in the Uu coverage, or the information provided by the relay-UE (e.g., the relay-UE may broadcast the serving cell information and optionally neighboring cell information for remote-UE to make a selection) . In an embodiment, the measurement report from the remote-UE may also indicate the preferred gNB cell, e.g., considering the information (e.g., PLMN ID) in the System Information Blocks (SIBs) of the gNB cell, as well as other information of the remote-UE (e.g., slicing information) . The measurement report may also indicate the remote-UE’s interest to use INACTIVE. In another example, the measurement report may also include an indication of the remote UE’s capability to use INACTIVE, as well as the remote-UE’s capability to use Option 1 or Option 2. Alternatively, the remote-UE’s capability and/or the remote-UE’s interest to use INACTIVE may be provided in a message separate to the measurement report.

Continuing with the example of Fig. 5, at 502, the relay-UE may send a non-access stratum (NAS) message indicating the need to use INACTIVE for the remote-UE, to the CN node (e.g., AMF) associated with the relay. The NAS message may indicate the information of the neighboring gNB cells and the preferred gNB cell. In some embodiments, the relay-UE may select a different AMF than the one serving the relay-UE. This selection may be based, for example, on the information received from the remote-UE, e.g., PLMN ID, slicing information. In another example, the relay-UE may send the NAS message to its AMF. The relay-UE’s AMF may select the AMF for the remote-UE. The relay-UE’s AMF may then invoke a Nasmf service including the NAS message to the remote-UE’s AMF. According to some embodiments, both

procedure

501 and 502 may be performed, or one of

procedure

501 or 502 may be performed. A purpose of procedure 501 and/or 502 is to provide the remote-UE’s capability, INACTIVE interest, as well as the information of the candidate gNB/cell to be used for INACTIVE to the CN node. In some examples, the remote-UE may send a message including the remote-UE’s capability, INACTIVE interest, and information of the candidate gNB/cell to the relay-UE, which is then forwarded to the CN node.

In an embodiment, at 503, the CN node may decide to configure the remote-UE in RRC_INACTIVE. The CN node may make this decision based, for example, on: a need to provide a certain service continuity and/or power efficiency for the remote-UE as defined in the subscription or service profile of the remote-UE; a received request/indication/report from the remote-UE, the relay-UE, the serving gNB of the relay-UE, or NFs of the relay-UE or the remote-UE on, e.g., network connections, service flows, QoS, measurements (statuses or conditions) of either the relay-UE or the remote-UE, as well as the serving gNB or NFs of either the relay-UE or the remote-UE, etc. The CN node may request the RAN node to establish the RRC_INACTIVE context for the remote-UE. According to an embodiment, the CN node may select the gNB based on the gNB cell information received from the relay-UE at 501 and/or 502. The gNB may be the same or different to the gNB serving the relay-UE. However, in some embodiments, the CN node may make the decision on which gNB to select without the indication or measurement report from the remote-UE/relay-UE. In one example, the CN node may use the relay-UE’s serving gNB for the remote-UE. In some other embodiment, 503 may include multiple procedures performed between the CN node and RAN node, for example, to authenticate the remote-UE, to provide the user plane information including the uplink General Packet Radio System (GPRS) Tunneling Protocol Fully Qualified Tunnel Endpoint Identifier User Plane (GTP-U TEID) , the QoS information of the PDU session resource, etc to the RAN node. The key point is to provide the necessary UE context information to the RAN node in order to establish or modify the RRC inactive context for the remote UE.

As further illustrated in the example of Fig. 5, at 504, upon reception of the request from the CN node (e.g., AMF) , the RAN node may establish the RRC_INACTIVE context for the remote-UE, and may provide the established RRC_INACTIVE UE context for the remote-UE, which may include the suspend configuration parameter and other parameters, e.g., the AMF UE NGAP Identity (ID) , RAN UE NGAP Identity (ID) , the DL General Packet Radio System (GPRS) Tunneling Protocol Fully Qualified Tunnel Endpoint Identifier User Plane (GTP-U TEID) , etc. to the CN node. The suspend configuration parameter may be similar to a suspend configuration (SuspendConfig) information element (IE) in a RRC release (RRCRelease) message, but may include additional information related to the relay-UE. For example, a RAN notification area information (RAN-NotificationAreaInfo) IE may include a list of relay-UEs, which indicates to the remote-UE to perform an RNA update when the remote-UE connects to a different relay-UE that is not in the list of relay-UEs. Fig. 6 illustrates an example of RAN notification area information (RAN-NotificationAreaInfo) IE, according to one embodiment.

Continuing with the example of Fig. 5, at 505, the CN node may send the suspend configuration parameter for the remote-UE to the relay-UE, which may be further forwarded to the remote-UE. The suspend configuration parameter may be the same as the one received from the RAN node at 504, or the one that is updated by the CN modified based on the suspend configuration parameter received from the RAN node at 504. At 506, the remote-UE may enter RRC_INACTIVE state. When the CN node (e.g., UPF) receives a DL data for the remote-UE, the UPF may use the relay-UE’s PDU session to send the DL data to the relay-UE, and then to the remote-UE. It is noted that the CN node as depicted in the example of Fig. 5 is for providing or representing different NFs of the CN on both control-plane and user-plane. At 507, when there is a need to resume the RRC connection, e.g., when the connection with the relay-UE is interrupted, when QoS is degraded, or the like, the remote-UE and RAN node may follow the normal resume procedure. This enables fast and efficient RRC connection and PDU session setup for the Remote-UE, without requiring the Remote-UE to perform a full connection setup over Uu (including cell selection or reselection, initial access, RRC connection and PDU session setup) in order to get a direct access to the serving network.

Fig. 7a illustrates an example signaling diagram depicting an embodiment according to another option. In the example of Fig. 7a, the Remote-UE is RRC_IDLE and the CN node first requests the remote-UE to enter the RRC-CONNECTED, then enter RRC_INACTIVE state (i.e., corresponding to option 2 discussed above) . As illustrated in the example of Fig. 7a, at 700, the remote-UE is RRC_IDLE and the remote-UE is already connected to the CN via the relay-UE. Similar to procedure 501 of Fig. 5, at 701, the remote-UE may provide a measurement report to the relay-UE. At 702, the relay-UE may send a NAS message indicating the need to use INACTIVE for the remote-UE, to the CN node (e.g., AMF) associated with the relay. The NAS message may indicate the information of the neighboring gNB cells and the preferred gNB cell.

As further illustrated in the example of Fig. 7a, at 703, the CN node may decide to configure the remote-UE in RRC_INACTIVE. The CN node can make this decision based, for example, on: a need to provide a certain service continuity and/or power efficiency for the remote-UE as defined in the subscription or service profile of the remote-UE; a received request/indication/report from the remote-UE, the relay-UE, the serving gNB of the relay-UE, or NFs of the relay-UE or the remote-UE on, e.g., network connections, service flows, QoS, measurements (statuses or conditions) of either the relay-UE or the remote-UE as well as the serving gNB or NFs of either the relay-UE or the remote-UE, etc. The CN node may send a NAS message to the relay-UE to request INACTIVE for the remote-UE. The request may be further sent to the remote-UE. The CN node may make the decision without the indication or measurement report from the remote-UE/Relay-UE.

Continuing with the example of Fig. 7a, at 704, upon reception of the request, the remote-UE may initiate a service request procedure to move to RRC CONNECTED. After the remote-UE is RRC CONNECTED, the CN node may request the RAN node to configure the RRC_INACTIVE for the remote-UE. The gNB may then suspend the RRC connection with the Remote-UE. The RRCRelease message may include the SuspendConfig IE, which may be similar to the SuspendConfig discussed above in connection with Figs. 5 and 6. Alternatively, in an embodiment, when the remote-UE initiates the service request procedure, the remote-UE may indicate the purpose is for INACTIVE. For example, the remote-UE may include a new cause of RRC inactive state transition when the remote-UE request RRC connection establishment. Based on this indication, the RAN node may initiate the suspension procedure after the UE is RRC CONNECTED. This avoids the CN node sending an INACTIVE request to the RAN node.

At 705, the remote-UE may enter RRC_INACTIVE state. The remote-UE may send, at 706, a confirmation to the relay-UE. The relay-UE may send a NAS message to the CN node to confirm that the remote-UE is in RRC INACTIVE. When the CN node (e.g., UPF) receives a DL data for the remote-UE, the CN node may use the relay-UE’s PDU session to send the DL data to the relay-UE, and then to the Remote-UE. At 707, when there is a need to resume the RRC connection, for example when the connection with the relay-UE is interrupted, when QoS is degraded, or the like, the remote-UE and RAN node may perform the normal resume procedure. This enables fast and efficient RRC connection and PDU session setup for the Remote-UE, without requiring the Remote-UE to perform a full connection setup over Uu (including cell selection or reselection, initial access, RRC connection and PDU session setup) in order to get a direct access to the serving network.

Fig. 7b illustrates another signaling diagram as a variation of the example signaling diagram of Fig. 7a, according to an embodiment. In the example of Fig. 7b, the CN node may use the network initiated service request procedure to request the remote-UE to enter the RRC_CONNECTED state, and then enter RRC_INACTIVE state. As illustrated in Fig. 7b, the call flow is similar to that of Fig. 7a with the exception of procedure 713 in which the CN node may initiate the service request by the paging procedure. For example, the NGAP PAGING message may indicate the paging is related to a remote UE with PC5 connection to relay UE, for example, to indicate the Paging is to setup the INACTIVE context. This indication may be implemented, e.g., via a new codepoint in a Paging Origin IE. The RAN node may forward the indication to the remote-UE. When the remote-UE initiates the service request procedure, the remote-UE may indicate the purpose is for INACTIVE. For example, the remote-UE may include a new cause of RRC inactive state transition when the remote-UE request RRC connection establishment. Based on this indication, the RAN node may initiate the suspension procedure after the UE is RRC CONNECTED. This avoids the CN node sending an INACTIVE request to the RAN node.

Fig. 8a illustrates an example flow diagram of a method for enabling or facilitating a CN initiated establishment or modification of RRC inactive context for a remote UE that is in OoC or RRC idle state, according to one example embodiment. In certain example embodiments, the flow diagram of Fig. 8a may be performed by a network entity or network node in a communication system, such as LTE or 5G NR. For instance, in some example embodiments, the network node performing the method of Fig. 8a may include a base station, access node, eNB, gNB, CN node and/or NG-RAN node, or the like. In one example embodiment, the network node may be CN node, such as an AMF. For example, in some embodiments, the method of Fig. 8a may be performed by the CN node illustrated in Figs. 5-7 and may include one or more of the procedures performed by the CN, as discussed in detail above.

As illustrated in the example of Fig. 8a, the method may include, at 800, determining that an establishment or modification of a RRC inactive context for a remote UE is to be initiated. According to certain embodiments, the remote UE may be in OoC, RRC idle state, and/or RRC inactive state of a RAN. In an embodiment, the remote UE may be connected to a CN via a relay UE. For example, the remote UE may be served using the L3 relay with 3GPP RAT or an access point with non-3GPP RAT. In certain embodiments, the determining 800 may include deciding to configure the remote UE in RRC inactive state based, for example, on: a need to provide a certain service continuity and/or power efficiency for the remote UE, e.g., as defined in the subscription or service profile of the remote UE; or a received request/indication/report from the remote UE, from the relay UE, from the serving gNB of the relay UE, or from serving NF (s) of the relay UE or the remote UE on, e.g., network connections, service flows, QoS, measurements (statuses or conditions) of either the relay UE or the remote UE as well as the serving gNB or NFs of either the Relay UE or the Remote UE, etc.

According to some embodiments, the method may include receiving, from the remote UE or the relay UE, a measurement report on neighbouring cell measurements. For example, the measurement may indicate information on the neighboring gNB cells, based on the remote UE’s measurements when the remote UE is in the Uu coverage, or based on information provided by the relay UE (e.g., the relay UE may broadcast the serving cell information and optionally neighboring cell information for remote UE to make a selection) . In one embodiment, the remote UE may be configured to measure and report on, e.g., inter-cell measurement to the serving AMF of the remote UE. The remote UE may also receive measurement-related configuration from the relay UE, such as candidate neighbouring-cell list, time gap for performing measurement, etc. The remote UE may also indicate a preferred gNB cell, e.g., considering the information (e.g. PLMN ID) in the SIBs of the gNB cell, as well as other information of the remote UE (e.g., slicing information) . The measurement report may also indicate the remote UE’s interest to use the inactive state.

In certain embodiments, the method may include receiving, by the CN node, a NAS message from the relay UE or from remote UE indicating the need to use inactive state for the remote UE associated with the relay UE. The NAS message may indicate the information of the neighboring gNB cells and the preferred gNB cell. According to some embodiments, the relay UE may select a different CN node or AMF than the one serving the relay UE. This selection may be based on the information received from the remote UE, such as PLMN ID or slicing information.

In an embodiment, the method may also include, at 805, initiating to a selected network node an establishment request or modification request on the RRC inactive context for the remote UE. Alternatively or additionally, the method may include requesting the remote UE to transition into RRC connected state to a selected network node for a subsequent state transition to RRC inactive state (but not for a mode switch or HO) . For example, the selected network node may be a RAN node or gNB. According to one embodiment, the selected network node may be selected based on the gNB cell information received from the relay UE. In further embodiments, the selected network node may be selected based on, e.g., a provided neighbouring cell list received from the remote UE, the relay UE or the serving gNB of the relay UE. The selected network node may allow for selecting a different core network node (e.g., AMF) for establishing or modifying the RRC inactive context for the remote UE. The selected network node may be the same or different from the network node (e.g., gNB) serving the relay UE. In some embodiments, the decision on the network node to select may be done without the indication or measurement report from the remote UE or relay UE. In one embodiment, for example, the relay UE’s serving gNB may be selected for the remote UE. In another embodiment, the selected network node may be provided in a request or left for the remote UE to select within a given RAN-based Notification Area (RNA) .

According to a further example embodiment, the initiating 805 of the remote user equipment to transition into RRC connected to the selected network node for a state transition to RRC inactive state may include transmitting a paging message indicating that paging is related to PC5 to setup the INACTIVE state for the remote user equipment.

According to certain embodiments, the method of Fig. 8a may also include, at 810, receiving, from the selected network node, the established or modified RRC inactive context for the remote UE. The RRC inactive context may include the suspend configuration parameter and other parameters, e.g., the AMF UE NGAP Identity (ID) , RAN UE NGAP Identity (ID) , the DL General Packet Radio System (GPRS) Tunneling Protocol Fully Qualified Tunnel Endpoint Identifier User Plane (GTP-U TEID) , etc. to the CN node. The method may also include, at 815, updating the established or modified RRC inactive context and related configurations for the remote UE. For instance, the updating 815 may include updating the established or modified RRC inactive UE context and related configurations (e.g., triggers or rules for updating and using the RRC_INACTIVE UE context for example) with the remote UE while the remote UE is being served using either the L3 relay 3GPP RAT or non-3GPP RAT.

In some embodiments, the method may also include receiving, from the remote UE, an indication of its UE capability. In this case, the method may also include informing the selected network node of the UE capability of the remote UE.

According to an embodiment, the method may include receiving a suspend configuration parameter that may include a list of relay UE (s) , and transmitting the suspend configuration parameter to the relay UE for forwarding to the remote UE. According to one example, the suspend configuration parameter and other parameters (e.g., DL GTP-U TEID) may be received from a RAN node. In an embodiment, the list of relay UE (s) may indicate to the remote UE to perform RNA update when the remote UE connects to a relay UE that is not in the list of relay UE (s) . In an example embodiment, the method may also include providing the remote UE with a time gap over PC5 interface to perform the state transition to RRC inactive state.

In an embodiment, when DL data is received for the remote-UE, the method may include using the relay UE’s PDU session to send the DL data to the relay UE, then to the Remote-UE. According to certain embodiments, when there is a need to resume the RRC connection, e.g., when the connection with the relay UE is interrupted, when there is degraded QoS, or other interruption, the normal resume procedure may be performed.

Fig. 8b illustrates an example flow diagram of a method for enabling or facilitating a CN initiated establishment or modification of RRC inactive context for a remote UE that is in OoC or RRC idle state, according to one example embodiment. In certain example embodiments, the flow diagram of Fig. 8b may be performed by a network entity or network node in a communications system, such as LTE or 5G NR. For instance, in some example embodiments, the network entity performing the method of Fig. 8b may include a UE, mobile station, user device, IoT device, or the like. For example, in an embodiment, the method of Fig. 8b may be performed by the remote UE illustrated in Figs. 5-7 and may include one or more of the procedures performed by the remote UE, as discussed in detail above. According to an embodiment, the remote UE may be in OoC or RRC idle state and may be connected to a CN via the relay UE.

In an embodiment, the method of Fig. 8b may include, at 830, transmitting a measurement report to a relay user equipment and/or a network node via a relay user equipment. The measurement report may include: a preferred cell, information on neighbouring cells, and/or an indication that the apparatus seeks to use the radio resource control (RRC) inactive state. In an embodiment, the method may include indicating a UE capability to the core network.

According to one embodiment, the method may include, at 835, receiving a request to transition to RRC inactive state. In an embodiment, the request may include the established or modified RRC inactive context for the remote UE. In an embodiment, the request may trigger the remote UE to get into RRC connected state to a selected network node for a state transition to RRC inactive state. In an embodiment, the request may be received from the relay UE or, that is, from a network node via the relay UE. In an embodiment, the request may be received from a network node directly, for example, a gNB. When the request is received from the network node directly, for example, a gNB, the remote UE may first perform a transition into RRC connected state to a selected network node. The remote UE may indicate the transition is for further transition to RRC inactive state, to the network node, for example, a gNB, by a new cause of RRC inactive state transition for requesting RRC connection establishment. Alternatively, the transition into RRC connected state may be based on the request from the network node, for example, a PAGING from the network node. After the remote UE is RRC CONNECTED, the network node may provide the suspension configuration parameter (s) to the remote UE. According to an embodiment, the method may include, at 840, transitioning from the OoC or RRC idle state to the RRC inactive state. In one example, the remote UE may receive a suspension configuration parameter (s) from the relay UE.

In some embodiment, the method may include indicating, to the core network, a preferred cell for the transition to the radio resource control (RRC) inactive state. According to an embodiment, the method may also include indicating, to the selected network node, a new cause of RRC inactive state transition for requesting RRC connection establishment. In certain embodiments, the method may include indicating L3 relay related context to the selected network node. In one embodiment, the method may include receiving a time gap over PC5 interface to perform the state transition to RRC inactive state. In another embodiment, the method may include receiving a suspend configuration parameter (s) which may include additional information related to the relay-UE, e.g., a RAN notification area information (RAN-NotificationAreaInfo) IE may include a list of relay-UEs, which indicates to the remote-UE to perform an RNA update when the UE connects to a different relay-UE that is not in the list of relay-UEs. In one example, the suspend configuration parameter (s) may be received with the request at 835 or 840.

According to an embodiment, the method may include receiving DL data from the CN via the relay UE. In some embodiments, when there is a need to resume the RRC connection, the method may include performing the normal resume procedure.

Fig. 8c illustrates an example flow diagram of a method for enabling or facilitating a CN initiated establishment or modification of RRC inactive context for a remote UE that is in OoC or RRC idle state, according to one example embodiment. In certain example embodiments, the flow diagram of Fig. 8c may be performed by a network entity or network node in a communication system, such as LTE or 5G NR. For instance, in some example embodiments, the network node performing the method of Fig. 8c may include a base station, access node, eNB, gNB, CN node and/or NG-RAN node, or the like. In one example embodiment, the network node may be a RAN node or gNB, e.g., as illustrated in the examples of Figs. 7a or 7b.

As illustrated in the example of Fig. 8c, the method may include, at 870, receiving a request to transition a remote UE from OoC or RRC idle state or RRC connected state to RRC inactive state. The method may also include, at 880, providing at least one suspend configuration parameter to the core network or to the remote UE. In one example, the method may also include, at 880, providing other parameters, e.g., the AMF UE NGAP Identity (ID) , RAN UE NGAP Identity (ID) , the DL General Packet Radio System (GPRS) Tunneling Protocol Fully Qualified Tunnel Endpoint Identifier User Plane (GTP-U TEID) to the core network. In an embodiment, the providing of the at least one suspend configuration parameter to the remote UE may be triggered based on receiving a RRC establishment request with an indication from the remote UE, and/or receiving a request from the core network.

Fig. 9a illustrates an example of an apparatus 10 according to an embodiment. In an embodiment, apparatus 10 may be a node, host, or server in a communications network or serving such a network. For example, apparatus 10 may be a satellite, base station, a Node B, an evolved Node B (eNB) , 5G Node B or access point, next generation Node B (NG-NB or gNB) , high altitude platform station (HAPS) , IAB node, and/or WLAN access point, associated with a radio access network, such as a LTE network, 5G or NR. In example embodiments, apparatus 10 may be or may include a core network node, such as an AMF or UPF, a RAN node, or the like.

It should be understood that, in some example embodiments, apparatus 10 may be comprised of an edge cloud server as a distributed computing system where the server and the radio node may be stand-alone apparatuses communicating with each other via a radio path or via a wired connection, or where they may be located in a same entity communicating via a wired connection. For instance, in certain example embodiments where apparatus 10 represents a gNB, it may be configured in a central unit (CU) and distributed unit (DU) architecture that divides the gNB functionality. In such an architecture, the CU may be a logical node that includes gNB functions such as transfer of user data, mobility control, radio access network sharing, positioning, and/or session management, etc. The CU may control the operation of DU (s) over a front-haul interface. The DU may be a logical node that includes a subset of the gNB functions, depending on the functional split option. It should be noted that one of ordinary skill in the art would understand that apparatus 10 may include components or features not shown in Fig. 9a.

As illustrated in the example of Fig. 9a, apparatus 10 may include a processor 12 for processing information and executing instructions or operations. Processor 12 may be any type of general or specific purpose processor. In fact, processor 12 may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) , field-programmable gate arrays (FPGAs) , application-specific integrated circuits (ASICs) , and processors based on a multi-core processor architecture, or any other processing means, as examples.

While a single processor 12 is shown in Fig. 9a, multiple processors may be utilized according to other example embodiments. For example, it should be understood that, in certain embodiments, apparatus 10 may include two or more processors that may form a multiprocessor system (e.g., in this case processor 12 may represent a multiprocessor) that may support multiprocessing. In some embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster) .

Processor 12 may perform functions associated with the operation of apparatus 10, which may include, for example, precoding of antenna gain/phase parameters, encoding and decoding of individual bits forming a communication message, formatting of information, and overall control of the apparatus 10, including processes related to management of communication resources.

Apparatus 10 may further include or be coupled to a memory 14 (internal or external) , which may be coupled to processor 12, for storing information and instructions that may be executed by processor 12. Memory 14 may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and/or removable memory. For example, memory 14 can be comprised of any combination of random access memory (RAM) , read only memory (ROM) , static storage such as a magnetic or optical disk, hard disk drive (HDD) , or any other type of non-transitory machine or computer readable media, or other appropriate storing means. The instructions stored in memory 14 may include program instructions or computer program code that, when executed by processor 12, enable the apparatus 10 to perform tasks as described herein.

In an embodiment, apparatus 10 may further include or be coupled to (internal or external) a drive or port that is configured to accept and read an external computer readable storage medium, such as an optical disc, USB drive, flash drive, or any other storage medium. For example, the external computer readable storage medium may store a computer program or software for execution by processor 12 and/or apparatus 10.

In some embodiments, apparatus 10 may also include or be coupled to one or more antennas 15 for transmitting and receiving signals and/or data to and from apparatus 10. Apparatus 10 may further include or be coupled to a transceiver 18 configured to transmit and/or receive information. The transceiver 18 may include, for example, a plurality of radio interfaces that may be coupled to the antenna (s) 15, or may include any other appropriate transceiving means. In certain embodiments, the radio interfaces may correspond to a plurality of radio access technologies including one or more of GSM, NB-IoT, LTE, 5G, WLAN, Bluetooth, BT-LE, NFC, radio frequency identifier (RFID) , ultrawideband (UWB) , MulteFire, and/or the like. According to an example embodiment, the radio interface may include components, such as filters, converters (e.g., digital-to-analog converters and the like) , mappers, a Fast Fourier Transform (FFT) module, and/or the like, e.g., to generate symbols or signals for transmission via one or more downlinks and to receive symbols (e.g., via an uplink) .

As such, transceiver 18 may be configured to modulate information on to a carrier waveform for transmission by the antenna (s) 15 and to demodulate information received via the antenna (s) 15 for further processing by other elements of apparatus 10. In other example embodiments, transceiver 18 may be capable of transmitting and receiving signals or data directly. Additionally or alternatively, in some embodiments, apparatus 10 may include an input device and/or output device (I/O device) , or an input/output means.

In an embodiment, memory 14 may store software modules that provide functionality when executed by processor 12. The modules may include, for example, an operating system that provides operating system functionality for apparatus 10. The memory may also store one or more functional modules, such as an application or program, to provide additional functionality for apparatus 10. The components of apparatus 10 may be implemented in hardware, or as any suitable combination of hardware and software.

According to some embodiments, processor 12 and memory 14 may be included in or may form a part of processing circuitry or control circuitry. In addition, in some embodiments, transceiver 18 may be included in or may form a part of transceiver circuitry.

As used herein, the term “circuitry” may refer to hardware-only circuitry implementations (e.g., analog and/or digital circuitry) , combinations of hardware circuits and software, combinations of analog and/or digital hardware circuits with software/firmware, any portions of hardware processor (s) with software (including digital signal processors) that work together to cause an apparatus (e.g., apparatus 10) to perform various functions, and/or hardware circuit (s) and/or processor (s) , or portions thereof, that use software for operation but where the software may not be present when it is not needed for operation. As a further example, as used herein, the term “circuitry” may also cover an implementation of merely a hardware circuit or processor (or multiple processors) , or portion of a hardware circuit or processor, and its accompanying software and/or firmware. The term circuitry may also cover, for example, a baseband integrated circuit in a server, cellular network node or device, or other computing or network device.

As introduced above, in certain embodiments, apparatus 10 may be a network node or RAN node, such as a base station, access point, Node B, eNB, gNB, HAPS, IAB node, WLAN access point, AMF, UPF, or the like. For example, in some embodiments, apparatus 10 may be configured to perform one or more of the processes depicted in any of the flow charts or signaling diagrams described herein, such as those illustrated in Figs. 5-8. In some embodiments, as discussed herein, apparatus 10 may be configured to perform a procedure relating to establishment or modification of RRC inactive context for a remote UE that is in OoC or RRC idle state.

According to this embodiment, apparatus 10 may be controlled by memory 14 and processor 12 to determine that an establishment or modification of a RRC inactive context for a remote UE is to be initiated. In an embodiment, the remote UE may be in OoC, RRC idle state, and/or RRC inactive state of a RAN and may be connected to a CN via a relay UE. For example, the remote UE may be served using the L3 relay with 3GPP RAT or an access point with non-3GPP RAT. In certain embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to decide to configure the remote UE in RRC inactive state based, for example, on: a need to provide a certain service continuity and/or power efficiency for the remote UE, e.g., as defined in the subscription or service profile of the remote UE; or a received request/indication/report from the remote UE, from the relay UE, from the serving gNB of the relay UE, or from serving NF (s) of the relay UE or the remote UE on, e.g., network connections, service flows, QoS, measurements (statuses or conditions) of either the relay UE or the remote UE as well as the serving gNB or NFs of either the Relay UE or the Remote UE, etc.

According to some embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to receive, from the remote UE or a relay UE, a measurement report on neighbouring cell measurements. For example, the measurement may indicate information on the neighboring gNB cells, based on the remote UE’s measurements when the remote UE is in the Uu coverage, or based on information provided by the relay UE (e.g., the relay UE may broadcast the serving cell information and optionally neighboring cell information for remote UE to make a selection) . In one embodiment, the remote UE may be configured to measure and report on, e.g., inter-cell measurement to the serving AMF of the remote UE. The remote UE may also receive measurement-related configuration from the relay UE, such as candidate neighbouring-cell list, time gap for performing measurement, etc. The apparatus 10 may also receive, from the remote UE, an indication of its preferred gNB cell, e.g., considering the information (e.g. PLMN ID) in the SIBs of the gNB cell, as well as other information of the remote UE (e.g., slicing information) . The apparatus 10 may also receive, from the remote UE, an indication of the remote UE’s interest to use inactive state.

In certain embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to receive a NAS message from the relay UE indicating the need to use inactive state for the remote UE associated with the relay. The NAS message may indicate the information of the neighboring gNB cells and the preferred gNB cell. According to some embodiments, the relay UE may select a different CN node or AMF than the one serving the relay UE. This selection may be based on the information received from the remote UE, such as PLMN ID or slicing information.

In an embodiment, apparatus 10 may be controlled by memory 14 and processor 12 to initiate to a selected network node an establishment request or a modification request on the RRC inactive context for the remote UE. Additionally or alternatively, apparatus 10 may be controlled by memory 14 and processor 12 to request the remote UE to transition into RRC connected state to a selected network node for a subsequent state transition to RRC inactive state (but not for a mode switch or HO) . For example, the selected network node may be a RAN node or gNB. According to one embodiment, the selected network node may be selected based on the gNB cell information received from the relay UE. In further embodiments, the selected network node may be selected based on, e.g., a provided neighbouring cell list received from the remote UE, the relay UE or the serving gNB of the relay UE. The selected network node may allow for selecting a different core network node (e.g., AMF) for establishing or modifying the RRC inactive context for the remote UE. The selected network node may be the same or different from the network node (e.g., gNB) serving the relay UE. In some embodiments, the decision on the network node to select may be done without the indication or measurement report from the remote UE or relay UE. In one embodiment, for example, the relay UE’s serving gNB may be selected for the remote UE. In another embodiment, the selected network node may be provided in a request or left for the remote UE to select within a given RAN-based Notification Area (RNA) .

According to an embodiment, to initiate the remote UE to transition into RRC connected to the selected network node for a state transition to RRC inactive state, apparatus 10 may be controlled by memory 14 and processor 12 to transmit a paging message indicating that paging is related to PC5 to setup the INACTIVE state for the remote user equipment.

According to certain embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to receive, from the selected network node, the established or modified RRC inactive context for the remote UE. In an embodiment, apparatus 10 may be controlled by memory 14 and processor 12 to update the established or modified RRC inactive context and related configurations for the remote UE. For instance, apparatus 10 may be controlled by memory 14 and processor 12 to update the established or modified RRC inactive UE context and related configurations (e.g., triggers or rules for updating and using the RRC_INACTIVE UE context for example) with the remote UE while the remote UE is being served using either the L3 relay with 3GPP RAT or an access point with non-3GPP RAT.

In some embodiments, apparatus 10 may be controlled by memory 14 and processor 12 to receive, from the remote UE, an indication of its UE capability. In this case, apparatus 10 may be controlled by memory 14 and processor 12 to inform the selected network node of the UE capability of the remote UE.

According to an embodiment, apparatus 10 may be controlled by memory 14 and processor 12 to receive a suspend configuration parameter that may include a list of relay UE (s) , and to transmit the suspend configuration parameter to the relay UE for forwarding to the remote UE. According to one example, the suspend configuration parameter and other parameters (e.g., the AMF UE NGAP Identity (ID) , RAN UE NGAP Identity (ID) , DL GTP-U TEID) may be received from a RAN node. In an embodiment, the list of relay UE (s) may indicate to the remote UE to perform RNA update when the remote UE connects to a relay UE that is not in the list of relay UE (s) . In an example embodiment, apparatus 10 may be controlled by memory 14 and processor 12 to provide the remote UE with a time gap over PC5 interface to perform the state transition to RRC inactive state.

In an embodiment, when DL data is received for the remote-UE, apparatus 10 may be controlled by memory 14 and processor 12 to use the relay UE’s PDU session to send the DL data to the relay UE, then to the Remote-UE. According to certain embodiments, when there is a need to resume the RRC connection, e.g., when the connection with the relay UE is interrupted, when there is degraded QoS, or other interruption, apparatus 10 may be controlled by memory 14 and processor 12 to perform the normal resume procedure.

Fig. 9b illustrates an example of an apparatus 20 according to another embodiment. In an embodiment, apparatus 20 may be a node or element in a communications network or associated with such a network, such as a UE, mobile equipment (ME) , mobile station, mobile device, stationary device, IoT device, or other device. As described herein, UE may alternatively be referred to as, for example, a mobile station, mobile equipment, mobile unit, mobile device, user device, subscriber station, wireless terminal, tablet, smart phone, IoT device, sensor or NB-IoT device, or the like. As one example, apparatus 20 may be implemented in, for instance, a wireless handheld device, a wireless plug-in accessory, or the like.

In some example embodiments, apparatus 20 may include one or more processors, one or more computer-readable storage medium (for example, memory, storage, or the like) , one or more radio access components (for example, a modem, a transceiver, or the like) , and/or a user interface. In some embodiments, apparatus 20 may be configured to operate using one or more radio access technologies, such as GSM, LTE, LTE-A, NR, 5G, WLAN, WiFi, NB-IoT, Bluetooth, NFC, MulteFire, and/or any other radio access technologies. It should be noted that one of ordinary skill in the art would understand that apparatus 20 may include components or features not shown in Fig. 9b.

As illustrated in the example of Fig. 9b, apparatus 20 may include or be coupled to a processor 22 (or processing means) for processing information and executing instructions or operations. Processor 22 may be any type of general or specific purpose processor. In fact, processor 22 may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) , field-programmable gate arrays (FPGAs) , application-specific integrated circuits (ASICs) , and processors based on a multi-core processor architecture, as examples. While a single processor 22 is shown in Fig. 9b, multiple processors may be utilized according to other embodiments. For example, it should be understood that, in certain embodiments, apparatus 20 may include two or more processors that may form a multiprocessor system (e.g., in this case processor 22 may represent a multiprocessor) that may support multiprocessing. In certain embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster) .

Processor 22 may perform functions associated with the operation of apparatus 20 including, as some examples, precoding of antenna gain/phase parameters, encoding and decoding of individual bits forming a communication message, formatting of information, and overall control of the apparatus 20, including processes related to management of communication resources.

Apparatus 20 may further include or be coupled to a memory 24 (internal or external) , which may be coupled to processor 22, for storing information and instructions that may be executed by processor 22. Memory 24 may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and/or removable memory. For example, memory 24 can be comprised of any combination of random access memory (RAM) , read only memory (ROM) , static storage such as a magnetic or optical disk, hard disk drive (HDD) , or any other type of non-transitory machine or computer readable media, or other storage means. The instructions stored in memory 24 may include program instructions or computer program code that, when executed by processor 22, enable the apparatus 20 to perform tasks as described herein.

In an embodiment, apparatus 20 may further include or be coupled to (internal or external) a drive or port that is configured to accept and read an external computer readable storage medium, such as an optical disc, USB drive, flash drive, or any other storage medium. For example, the external computer readable storage medium may store a computer program or software for execution by processor 22 and/or apparatus 20.

In some embodiments, apparatus 20 may also include or be coupled to one or more antennas 25 for receiving a downlink signal and for transmitting via an uplink from apparatus 20. Apparatus 20 may further include a transceiver 28 (or transceiving means) configured to transmit and receive information. The transceiver 28 may also include a radio interface (e.g., a modem) coupled to the antenna 25. The radio interface may correspond to a plurality of radio access technologies including one or more of GSM, LTE, LTE-A, 5G, NR, WLAN, NB-IoT, Bluetooth, BT-LE, NFC, RFID, UWB, and the like. The radio interface may include other components, such as filters, converters (for example, digital-to-analog converters and the like) , symbol demappers, signal shaping components, an Inverse Fast Fourier Transform (IFFT) module, and the like, to process symbols, such as OFDMA symbols, carried by a downlink or an uplink.

For instance, transceiver 28 may be configured to modulate information on to a carrier waveform for transmission by the antenna (s) 25 and demodulate information received via the antenna (s) 25 for further processing by other elements of apparatus 20. In other embodiments, transceiver 28 may be capable of transmitting and receiving signals or data directly. Additionally or alternatively, in some embodiments, apparatus 20 may include an input and/or output device (I/O device) or input/output means. In certain embodiments, apparatus 20 may further include a user interface, such as a graphical user interface or touchscreen.

In an embodiment, memory 24 stores software modules that provide functionality when executed by processor 22. The modules may include, for example, an operating system that provides operating system functionality for apparatus 20. The memory may also store one or more functional modules, such as an application or program, to provide additional functionality for apparatus 20. The components of apparatus 20 may be implemented in hardware, or as any suitable combination of hardware and software. According to an example embodiment, apparatus 20 may optionally be configured to communicate with apparatus 10 via a wireless or wired communications link 70 according to any radio access technology, such as NR.

According to some embodiments, processor 22 and memory 24 may be included in or may form a part of processing circuitry or control circuitry. In addition, in some embodiments, transceiver 28 may be included in or may form a part of transceiving circuitry.

As discussed above, according to some embodiments, apparatus 20 may be a UE, mobile device, mobile station, ME, IoT device and/or NB-IoT device, for example. According to certain embodiments, apparatus 20 may be controlled by memory 24 and processor 22 to perform the functions associated with example embodiments described herein. For example, in some embodiments, apparatus 20 may be configured to perform one or more of the processes depicted in any of the flow charts or signaling diagrams described herein, such as those illustrated in Figs. 5-8. For instance, in an embodiment, apparatus 20 may be a remote UE as illustrated in Figs. 5-7 and may perform any of the procedures depicted therein. In certain embodiments, apparatus 20 may be configured to perform a process relating to the establishment or modification of RRC inactive context for the apparatus 20, which may begin in OoC or RRC idle state and may be connected to a CN via a relay UE, for instance.

For example, in some embodiments, apparatus 20 may be controlled by memory 24 and processor 22 to transmit a measurement report to a relay UE and/or to a network node via a relay UE. The measurement report may include one or more of: information on neighbouring cells, and/or an indication that the apparatus seeks to use the radio resource control (RRC) inactive state. In an embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to indicate a UE capability to the CN.

According to one embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to receive a request to transition into RRC inactive state. In an embodiment, the request may include the established or modified RRC inactive context for the apparatus 20. In an embodiment, the request may trigger the apparatus 20 to get into RRC connected state to a selected network node for a state transition to RRC inactive state. In an embodiment, the request may be received from the relay UE or, that is, from a network node via the relay UE. In an embodiment, the request may be received from a network node directly, for example, a gNB. When the request is received from the network node directly, for example from a gNB, apparatus 20 may be controlled by memory 24 and processor 22 to first perform a transition into RRC connected state to a selected network node. In this embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to indicate the transition is for further transition to RRC inactive state, to the network node, such as a gNB, by a new cause of RRC inactive state transition for requesting RRC connection establishment. Alternatively, the transition into RRC connected state may be based on the request from the network node, for example, a PAGING from the network node. In an embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to transition from the OoC or RRC idle state to the RRC inactive state.

In some embodiments, apparatus 20 may be controlled by memory 24 and processor 22 to indicate, to the CN, a preferred cell for the transition to the radio resource control (RRC) inactive state. According to an embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to indicate, to the selected network node, a new cause of RRC inactive state transition for requesting RRC connection establishment. In certain embodiments, apparatus 20 may be controlled by memory 24 and processor 22 to indicate L3 relay related context to the selected network node. In one embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to receive a time gap over PC5 interface to perform the state transition to RRC inactive state. In another embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to receive a suspend configuration parameter (s) which may include additional information related to the relay-UE, e.g., a RAN notification area information (RAN-NotificationAreaInfo) IE may include a list of relay-UEs, which indicates to the apparatus 20 to perform an RNA update when the apparatus 20 connects to a different relay-UE that is not in the list of relay-UEs. In one example, the suspend configuration parameter (s) may be received with the request to transition into RRC inactive state.

According to an embodiment, apparatus 20 may be controlled by memory 24 and processor 22 to receive DL data from the CN via the relay UE. In some embodiments, when there is a need to resume the RRC connection, apparatus 20 may be controlled by memory 24 and processor 22 to perform the normal resume procedure.

Therefore, certain example embodiments provide several technological improvements, enhancements, and/or advantages over existing technological processes and constitute an improvement at least to the technological field of wireless network control and management. As discussed in detail above, certain embodiments enable and facilitate fast and efficient RRC connection and PDU session setup for a remote UE, for example, when the remote UE seeks to return to the direct network access, e.g., using Uu from the current network access using L3 Relay with 3GPP RAT or an access point with non-3GPP RAT. Accordingly, the use of certain example embodiments results in improved functioning of communications networks and their nodes, such as base stations, eNBs, gNBs, and/or UEs or mobile stations.

In some example embodiments, the functionality of any of the methods, processes, signaling diagrams, algorithms or flow charts described herein may be implemented by software and/or computer program code or portions of code stored in memory or other computer readable or tangible media, and executed by a processor.

In some example embodiments, an apparatus may be included or be associated with at least one software application, module, unit or entity configured as arithmetic operation (s) , or as a program or portions of it (including an added or updated software routine) , executed by at least one operation processor. Programs, also called program products or computer programs, including software routines, applets and macros, may be stored in any apparatus-readable data storage medium and may include program instructions to perform particular tasks.

A computer program product may include one or more computer-executable components which, when the program is run, are configured to carry out some example embodiments. The one or more computer-executable components may be at least one software code or portions of code. Modifications and configurations required for implementing functionality of an example embodiment may be performed as routine (s) , which may be implemented as added or updated software routine (s) . In one example, software routine (s) may be downloaded into the apparatus.

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

In other example embodiments, the functionality may be performed by hardware or circuitry included in an apparatus, for example through the use of an application specific integrated circuit (ASIC) , a programmable gate array (PGA) , a field programmable gate array (FPGA) , or any other combination of hardware and software. In yet another example embodiment, the functionality may be implemented as a signal, such as a non-tangible means, that can be carried by an electromagnetic signal downloaded from the Internet or other network.

According to an example embodiment, an apparatus, such as a node, device, or a corresponding component, may be configured as circuitry, a computer or a microprocessor, such as single-chip computer element, or as a chipset, which may include at least a memory for providing storage capacity used for arithmetic operation (s) and/or an operation processor for executing the arithmetic operation (s) .

One having ordinary skill in the art will readily understand that the example embodiments as discussed above may be practiced with procedures in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although some embodiments have been described based upon these example embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of example embodiments.

Claims

An apparatus, comprising:

at least one processor; and

at least one memory comprising computer program code,

the at least one memory and computer program code configured, with the at least one processor, to cause the apparatus at least to

determine that an establishment or modification of a radio resource control (RRC) inactive context for a remote user equipment is to be initiated, wherein the remote user equipment is in out-of-coverage, radio resource control (RRC) idle state, or radio resource control (RRC) inactive state of a radio access network;

initiate to a selected network node an establishment request or a modification request on the radio resource control (RRC) inactive context for the remote user equipment.
The apparatus according to claim 1, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to:

receive, from the selected network node, the established or modified radio resource control (RRC) inactive context for the remote user equipment; and

update the established or modified radio resource control (RRC) inactive context and related configurations for the remote user equipment.
The apparatus according to claim 1, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to:

request the remote user equipment to transition into radio resource control (RRC) connected to a selected network node for a state transition to radio resource control (RRC) inactive state.
The apparatus according to any of claims 1-3, wherein the apparatus is configured to determine that the establishment or modification of the radio resource control (RRC) inactive context for the remote user equipment is to be initiated based on at least one of:

a need to provide a certain service continuity and/or power efficiency for the remote user equipment; or

a received request, indication, or report from the remote user equipment, or from the relay user equipment, or from a serving network node of the relay user equipment, or from a serving network function (NF) of the relay user equipment or the remote user equipment.
The apparatus according to any of claims 1-4, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to:

receive, from the remote user equipment or from the relay user equipment, a report on neighboring cell measurements.
The apparatus according to any of claims 1-5, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to:

receive, from the remote user equipment, an indication of user equipment capability; and

inform the selected network node of the user equipment capability of the remote user equipment.
The apparatus according to any of claims 1-6, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to:

receive a suspend configuration parameter, wherein the suspend configuration parameter comprises a list of relay user equipment; and

transmit the suspend configuration parameter to the relay user equipment for forwarding to the remote user equipment; and

provide the remote user equipment with a time gap over PC5 interface to perform the state transition to radio resource control (RRC) inactive state.
The apparatus according to any of claims 1-7, wherein the selected network node is the same or different from a network node serving the relay user equipment.
The apparatus according to any of claims 1-8, wherein the selected network node is selected based on a report received from one of the remote user equipment, the relay user equipment or a serving network node of the relay user equipment.
The apparatus according to any of claims 1-9, wherein, to request the remote user equipment to transition into radio resource control (RRC) connected to a selected network node for a state transition to radio resource control (RRC) inactive state, the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to:

transmit a paging message indicating that paging is related to PC5 to setup the INACTIVE state for the remote user equipment.
The apparatus according to any of claims 1-10, wherein the remote user equipment is connected to a core network via a relay user equipment.
A method, comprising:

determining, by a core network node, that an establishment or modification of a radio resource control (RRC) inactive context for a remote user equipment is to be initiated, wherein the remote user equipment is in out-of-coverage, radio resource control (RRC) idle state, or radio resource control (RRC) inactive state of a radio access network;

initiating to a selected network node an establishment request or a modification request on the radio resource control (RRC) inactive context for the remote user equipment.
The method according to claim 12, further comprising:

receiving, from the selected network node, the established or modified radio resource control (RRC) inactive context for the remote user equipment; and

updating the established or modified radio resource control (RRC) inactive context and related configurations for the remote user equipment.
The method according to claims 12 or 13, further comprising:

requesting the remote user equipment to transition into radio resource control (RRC) connected to a selected network node for a state transition to radio resource control (RRC) inactive state.
The method according to any of claims 12-14, wherein the determining that the establishment or modification of the radio resource control (RRC) inactive context for the remote user equipment is to be initiated is based on at least one of:

a need to provide a certain service continuity and/or power efficiency for the remote user equipment; or

a received request, indication, or report from the remote user equipment, or from the relay user equipment, or from a serving network node of the relay user equipment, or from a serving network function (NF) of the relay user equipment or the remote user equipment.
The method according to any of claims 12-15, further comprising:

receiving, from the remote user equipment or from the relay user equipment, a report on neighboring cell measurements.
The method according to any of claims 12-16, further comprising:

receiving, from the remote user equipment, an indication of user equipment capability; and

informing the selected network node of the user equipment capability of the remote user equipment.
The method according to any of claims 12-17, further comprising:

receiving a suspend configuration parameter, wherein the suspend configuration parameter comprises a list of relay user equipment;

transmitting the suspend configuration parameter to the relay user equipment for forwarding to the remote user equipment; and

providing the remote user equipment with a time gap over PC5 interface to perform the state transition to radio resource control (RRC) inactive state.
The method according to any of claims 12-18, wherein the selected network node is the same or different from a network node serving the relay user equipment.
The method according to any of claims 12-19, wherein the selected network node is selected based on a report received from one of the remote user equipment, the relay user equipment or a serving network node of the relay user equipment.
The method according to any of claims 12-20, wherein said requesting the remote user equipment to transition into radio resource control (RRC) connected to the selected network node for the state transition to radio resource control (RRC) inactive state, the method further comprises:

transmitting a paging message indicating that paging is related to PC5 to setup the INACTIVE state for the remote user equipment.
The method according to any of claims 12-21, wherein the remote user equipment is connected to a core network via a relay user equipment.
An apparatus, comprising:

at least one processor; and

at least one memory comprising computer program code,

the at least one memory and computer program code configured, with the at least one processor, to cause the apparatus at least to

transmit a measurement report to a relay user equipment, wherein the apparatus is in out-of-coverage (OoC) or radio resource control (RRC) idle state and is connected to a core network via the relay user equipment;

receive a request to transition into radio resource control (RRC) inactive state; and

transition from the out-of-coverage (OoC) or radio resource control (RRC) idle state to the radio resource control (RRC) inactive state.
The apparatus according to claim 23, wherein the request comprises a request to transition into radio resource control (RRC) connected state to a selected network node for the state transition to the radio resource control (RRC) inactive state.
The apparatus according to claims 23 or 24, wherein the measurement report further comprises at least one of: information on neighbouring cells, or information on preferred network node, or an indication that the apparatus seeks to use the radio resource control (RRC) inactive state.
The apparatus according to any of claims 23-25, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to indicate a user equipment capability to the core network.
The apparatus according to any of claims 23-26, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus to receive the request for transition to the radio resource control (RRC) inactive state from the relay user equipment, or from the selected network node.
The apparatus according to any of claims 23-27, wherein the request comprises at least a suspend configuration parameter.
The apparatus according to any of claims 23-28, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to indicate, to the selected network node, a new cause of radio resource control (RRC) inactive state transition for requesting radio resource control (RRC) connection establishment.
The apparatus according to any of claims 23-29, wherein the at least one memory and computer program code are configured, with the at least one processor, to cause the apparatus at least to receive a time gap over PC5 interface to perform the state transition to radio resource control (RRC) inactive state.
A method, comprising:

transmitting, by a remote user equipment, a measurement report to a relay user equipment, wherein the remote user equipment is in out-of-coverage (OoC) or radio resource control (RRC) idle state and is connected to a core network via the relay user equipment;

receiving a request to transition into radio resource control (RRC) inactive state; and

transitioning, by the remote user equipment, from the out-of-coverage (OoC) or radio resource control (RRC) idle state to the radio resource control (RRC) inactive state.
The method according to claim 31, wherein the request comprises a request to transition into radio resource control (RRC) connected state to a selected network node for the state transition to the radio resource control (RRC) inactive state.
The method according to claims 31 or 32, wherein the measurement report further comprises at least one of: information on neighbouring cells, or information on preferred network node, or an indication that the apparatus seeks to use the radio resource control (RRC) inactive state.
The method according to any of claims 31-33, further comprising indicating a user equipment capability to the core network.
The method according to any of claims 31-34, further comprising receiving the request for transition to the radio resource control (RRC) inactive state from the relay user equipment, or from the selected network node.
The method according to any of claims 31-35, wherein the request comprises at least a suspend configuration parameter.
The method according to any of claims 31-36, further comprising indicating, to the selected network node, a new cause of radio resource control (RRC) inactive state transition for requesting radio resource control (RRC) connection establishment.
The method according to any of claims 31-37, further comprising receiving a time gap over PC5 interface to perform the state transition to radio resource control (RRC) inactive state.
An apparatus, comprising:

at least one processor; and

at least one memory comprising computer program code,

the at least one memory and computer program code configured, with the at least one processor, to cause the apparatus at least to

receive a request to transition a remote user equipment from out-of-coverage (OoC) or radio resource control (RRC) idle state or radio resource control (RRC) connected state to radio resource control (RRC) inactive state; and

provide at least one suspend configuration parameter to the core network or to the remote user equipment.
The apparatus according to claim 39, wherein the providing of the at least one suspend configuration parameter to the remote user equipment is triggered based on at least one of:

receiving a radio resource control (RRC) establishment request with an indication from the remote user equipment; or

a request from the core network.
A method, comprising:

receiving, at a network node, a request to transition a remote user equipment from out-of-coverage (OoC) or radio resource control (RRC) idle state or radio resource control (RRC) connected state to radio resource control (RRC) inactive state; and

providing at least one suspend configuration parameter to the core network or to the remote user equipment.
The method according to claim 41, wherein the providing of the at least one suspend configuration parameter to the remote user equipment is triggered based on at least one of:

receiving a radio resource control (RRC) establishment request with an indication from the remote user equipment; or

a request from the core network.
An apparatus, comprising:

means for determining that an establishment or modification of a radio resource control (RRC) inactive context for a remote user equipment is to be initiated, wherein the remote user equipment is in out-of-coverage, radio resource control (RRC) idle state, or radio resource control (RRC) inactive state of a radio access network;

means for initiating to a selected network node an establishment request or a modification request on the radio resource control (RRC) inactive context for the remote user equipment.
An apparatus, comprising:

means for transmitting a measurement report to a relay user equipment, wherein the apparatus is in out-of-coverage (OoC) or radio resource control (RRC) idle state and is connected to a core network via the relay user equipment;

means for receiving a request to transition into radio resource control (RRC) inactive state; and

means for transitioning from the out-of-coverage (OoC) or radio resource control (RRC) idle state to the radio resource control (RRC) inactive state.
An apparatus, comprising:

means for receiving a request to transition a remote user equipment from out-of-coverage (OoC) or radio resource control (RRC) idle state to radio resource control (RRC) inactive state; and

means for providing at least one suspend configuration parameter to the core network or to the remote user equipment.
A computer readable medium comprising program instructions stored thereon for performing at least the method according to any of claims 12-22, 31-38, or 41-42.