Patent Description:
The UE may use Discontinuous Reception (DRX) in RRC_IDLE and RRC_INACTIVE state in order to reduce power consumption. The UE monitors one paging occasion (PO) per DRX cycle. A PO is a set of PDCCH monitoring occasions and can consist of multiple time slots (e.g. subframe or OFDM symbol) where paging DCI can be sent <NPL> ([<NUM>]). One Paging Frame (PF) is one Radio Frame and may contain one or multiple PO(s) or starting point of a PO.

In multi-beam operations, the UE assumes that the same paging message and the same Short Message are repeated in all transmitted beams and thus the selection of the beam(s) for the reception of the paging message and Short Message is up to UE implementation. The paging message is same for both RAN initiated paging and CN initiated paging.

The UE initiates RRC Connection Resume procedure upon receiving RAN initiated paging. If the UE receives a CN initiated paging in RRC _INACTIVE state, the UE moves to RRC_IDLE and informs NAS.

The PF and PO for paging are determined by the following formulae: SFN for the PF is determined by:<MAT> Index (i_s), indicating the index of the PO is determined by:<MAT>.

The PDCCH monitoring occasions for paging are determined according to pagingSearchSpace as specified in [<NUM>] and firstPDCCH-MonitoringOccasionOfPO if configured as specified in [<NUM>]. When SearchSpaceId = <NUM> is configured for pagingSearchSpace, the PDCCH monitoring occasions for paging are same as for RMSI as defined in clause <NUM> in [<NUM>].

When SearchSpaceId = <NUM> is configured for pagingSearchSpace, Ns is either <NUM> or <NUM>. For Ns = <NUM>, there is only one PO which starts from the first PDCCH monitoring occasion for paging in the PF. For Ns = <NUM>, PO is either in the first half frame (i_s = <NUM>) or the second half frame (i_s = <NUM>) of the PF.

When SearchSpaceId other than <NUM> is configured for pagingSearchSpace, the UE monitors the (i_s + <NUM>)th PO. A PO is a set of 'S' consecutive PDCCH monitoring occasions where 'S' is the number of actual transmitted SSBs determined according to ssb-PositionsInBurst in SIB1. The Kth PDCCH monitoring occasion for paging in the PO corresponds to the Kth transmitted SSB. The PDCCH monitoring occasions for paging which do not overlap with UL symbols (determined according to tdd-UL-DL-ConfigurationCommon) are sequentially numbered from zero starting from the first PDCCH monitoring occasion for paging in the PF. When firstPDCCH-MonitoringOccasionOfPO is present, the starting PDCCH monitoring occasion number of (i_s + <NUM>)th PO is the (i_s + <NUM>)th value of the firstPDCCH-MonitoringOccasionOfPO parameter; otherwise, it is equal to i_s * S.

NOTE <NUM>: A PO associated with a PF may start in the PF or after the PF.

NOTE <NUM>: The PDCCH monitoring occasions for a PO can span multiple radio frames. When SearchSpaceId other than <NUM> is configured for paging-SearchSpace the PDCCH monitoring occasions for a PO can span multiple periods of the paging search space.

The following parameters are used for the calculation of PF and i_s above:.

Parameters Ns, nAndPagingFrameOffset, and the length of default DRX Cycle are signaled in S1B1. The values of N and PF_offset are derived from the parameter nAndPagingFrameOffset as defined in <NPL> ([<NUM>]). The parameter first-PDCCH-MonitoringOccasionOfPO is signalled in SIB1 for paging in initial DL BWP. For paging in a DL BWP other than the initial DL BWP, the parameter first-PDCCH-MonitoringOccasionOfPO is signaled in the corresponding BWP configuration.

If the UE has no <NUM>-S-TMSI, for instance when the UE has not yet registered onto the network, the UE shall use as default identity UE_ID = <NUM> in the PF and i_s formulas above.

<NUM>-S-TMSI is a <NUM>-bit long bit string as defined in <NPL> ([<NUM>]). <NUM>-S-TMSI shall in the formulae above be interpreted as a binary number where the left most bit represents the most significant bit.

For protocol architecture for the user plane and control plane, relaying is performed above RLC sublayer. The evolved ProSe Remote UE's user plane and control plane data are relayed above RLC via the evolved ProSe UE-to-Network Relay UE from the evolved ProSe Remote UE to network and vice versa. Uu PDCP and RRC are terminated between the evolved ProSe Remote UE and the eNB while RLC, MAC and PHY and the non-3GPP transport layers are terminated in each link (i.e. the link between the evolved ProSe Remote UE and the evolved ProSe UE-to-Network Relay UE and the link between the evolved ProSe UE-to-Network Relay UE and the eNB). The user plane protocol stack and the control plane protocol stack when PC5 is used between the evolved ProSe remote UE and the evolved ProSe UE-to-Network Relay UE is shown in <FIG> and <FIG>.

It is assumed that the evolved ProSe Remote UE should be linked with the evolved ProSe UE-to-Network Relay UE in order to receive paging via the evolved ProSe UE-to-Network Relay UE. The evolved ProSe Remote UE supports reception of paging over the linked evolved ProSe UE-to-Network Relay UE while the evolved ProSe Remote UE is in and out of E-UTRAN coverage. The evolved ProSe UE-to-Network Relay UE supports forwarding of paging for the evolved ProSe Remote UE located in and out of E-UTRAN coverage. There are multiple possible paging options with which the evolved ProSe Remote UE in RRC_IDLE can be reachable in downlink when it is in E-UTRAN coverage or out of E-UTRAN coverage as shown below.

Option <NUM>: The evolved ProSe UE-to-Network Relay UE monitors its linked evolved ProSe Remote UE's PO in addition to its own PO. The evolved ProSe Remote UE does not need to attempt paging reception over downlink while linked to the evolved ProSe UE-to-Network Relay UE. The evolved ProSe UE-to-Network Relay UE may need to monitor multiple paging occasions. The evolved ProSe UE-to-Network Relay UE has to know the paging occasion of the evolved ProSe Remote UE and has to decode a paging message and determine which evolved ProSe Remote UE the paging is for. Also, the evolved ProSe UE-to-Network Relay UE may need to relay the evolved ProSe Remote UE's paging over short range link. This option is shown in <FIG>.

Option <NUM>: The evolved ProSe UE-to-Network Relay UE monitors its own PO only and paging for the linked evolved ProSe Remote UE is also sent in the evolved ProSe UE-to-Network Relay UE's PO. The evolved ProSe Remote UE does not need to attempt paging reception over downlink while linked to the evolved ProSe UE-to-Network Relay UE. The evolved ProSe UE-to-Network Relay UE has to decode a paging message, determine which evolved ProSe Remote UE the paging is for and needs to relay the evolved ProSe Remote UE's paging over short range link. In order to page the evolved ProSe Remote UE, the core network (i.e. MME) is required to know linked status between the evolved ProSe UE-to-Network Relay UE and the evolved ProSe Remote UE and remap evolved ProSe Remote UE's paging messages to occur on evolved ProSe UE-to-Network Relay UE's POs when evolved ProSe Remote UE are linked. This option is shown in <FIG>.

This background information is provided to reveal information believed by the applicant to be of possible relevance. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art. <CIT> discloses an arrangement in which a UE is configured to operate as a Relay between a Remote UE and a gNB.

Various aspects and features are defined in the appended claims. Disclosed herein is subject matter that may address issues for sending a paging message to a remote UE that is more than one hop from a base station. Specifically, the following subject matter is disclosed.

Relay UE election methods are disclosed for enabling or disabling the relay function of a relay capable UE to act as a UE-to-NW relay or UE-to-UE relay for paging message.

Paging path establishment methods are disclosed for establishing a path between a remote UE and a gNB before the gNB sends out a paging message to the remote UE. A paging path discovery procedure is disclosed for a gNB to discover multiple candidate paging paths between the remote UE and the gNB. Paging path configuration procedures are disclosed for a gNB to select and configure the adaptation layer of the UE-to-NW Relay and zero or more UE-to-UE Relays that forward the paging along the paging path. Also disclosed is a selection-based paging path establishment method that the remote UE establishes its paging path along the paging path of the relay UE by configuring the adaptation layer of UE-to-UE relays and the UE-to-NW relay on the paging path.

Paging propagation methods are disclosed for propagating a paging message from a gNB to a remote UE via an established paging path. In a first disclosed method, the UE-to-NW Relay UE monitors the remote UE's PO in addition to its own PO. In a second disclosed method, the UE-to-NW relay monitors its own PO only and paging for the remote UE is also sent in the UE-to-Network Relay UE's PO.

Paging path maintenance methods are disclosed for the remote UE, UE-to-UE relays, or UE-to-NW relays in the network dynamically maintaining the paging path between the remote UE and gNB when the topology changes. In a first disclosed method, a remote UE may select a new relay UE and establish a new paging path to the gNB. In a second disclosed method, one or more relay UEs on the paging path of the remote UE may select a new relay UE and establish a new paging path to the gNB.

UE reachability management methods are disclosed for a remote UE to maintain the paging path by periodically sending path update messages.

In LTE and NR, the granularity for location context of a UE is at "Tracking Area" when a UE is in RRC_Idle and is at "RAN Notification Area" when a UE is in RRC_Inactive. To send a paging to a UE, a gNB within the TA and RNA broadcasts paging to all UEs within the area. However, in the scenario that there are multiple relays in an area, broadcast paging by relay UEs will cause paging message flooding in the area which introduces significant overhead. Therefore, there is a need to establish one or more paging paths to propagate a paging message from gNB to a remote UE. The first set of issues need to be addressed is how one or more paging paths are established between a gNB and a remote UE.

Issue <NUM> - Relay UE (s) election for relaying of paging: In the network, some UEs support a relay function to relay paging message and some do not, for example due to their hardware and software capability. However, for UEs that support the relay function, the relay function may not be enabled or elected to relay paging message as a result of UE conditions or network conditions. How does the relay function of a relay capable UE become enabled to act as a relay for paging message?.

Issue <NUM> - Remote UE selection of a Relay UE for paging reception: If a remote UE needs to select a (new)Relay UE for paging reception, how does a remote UE select a relay UE for paging reception?.

Issue <NUM> - Determination by the relay UE of which remote UE(s) to forward paging to: How does the relay UE know about which remote UE to relay paging to? Is this knowledge implicit or explicit?.

Issue <NUM> - Knowledge of Remote UE POs at the relay UE: How does the relay UE know the POs of the remote UEs paging are being relayed to?.

The remote UE may be moving. The mobility of remote UE introduces another set of issues.

Issue <NUM> - Traditional RAN area update procedure, registration area update procedure, or UE periodic registration area update are limited to one hop. The UE needs to switch to RRC connected mode to send a RANU or Registration area update. How a remote UE maintains UE reachability status in the NW (CN or RAN) through other relay UEs should be addressed.

Issue <NUM> - How can the paging relay path be quickly reestablished so that the remote UE can seamlessly receive paging from the NW.

Disclosed herein is subject matter that may address issues for sending a paging message to a remote UE that is more than one hop from a base station. The disclosed subject matter includes a remote UE that establishes one or multiple paths to receive a paging message from a gNB or a relay UE that forwards a paging message from gNB to a remote UE.

Methods, systems, and apparatuses, among other things, as described herein may provide for paging a remote UE. A method, system, computer readable storage medium, or apparatus provides for receiving relay context information from one or multiple neighbor UEs; based on obtained relay context information, initiating a discovery-based paging path establishment procedure to discover and establish one or multiple paging paths between the remote UE and the gNB by sending paging path discovery request to one or multiple neighbor relay UEs to discovery one or multiple paths to the gNB and receiving paging path discovery response from neighbor UEs or gNB to confirm the establishment of a paging path; based on obtained relay context information, indicating a selection-based paging path establishment procedure that the remote UE establishes its paging path along the paging path of the remote UE's neighbor relay UE by sending a paging path establishment request to select and configure the remote UE's neighbor UEs that has established one or more paging path to a gNB and receiving a paging path establishment response to confirm the establishment of a paging path; selecting a new relay UE and establish a new paging path to the gNB; and maintaining the paging path and update the reachability of the network by sending path update towards the gNB.

The control plane protocol stack and the user plane protocol stack when PC5 is used between the remote UE, the UE-to-UE Relay UEs, and the UE-to-Network Relay UE to relay traffic is shown in <FIG> and <FIG>. For protocol architecture for the user plane and control plane, relaying is performed above RLC sublayer. The user plane of remote UE <NUM> and control plane data are relayed above RLC via UE-to-UE Relay UE <NUM> or UE-to-Network Relay UE <NUM> from remote UE <NUM> to network and vice versa. Uu PDCP and RRC are terminated between remote UE <NUM> and gNB <NUM> while RLC, MAC and PHY are terminated in each link (e.g., the link between remote UE <NUM> and UE-to-UE Relay UE <NUM>, the link between UE-to-UE Relay UE <NUM> and Network Relay UE <NUM>, and the link between the UE-to-Network Relay UE <NUM> and gNB <NUM>). In the following (e.g., <FIG> or <FIG>), the RLC layer is shown terminating on each hop. However, the RLC layer from remote UE <NUM> may also terminate at gNB <NUM>.

A paging message may by sent by gNB <NUM> and forwarded by UE-to-NW relay <NUM> and zero or more UE-to-UE relays <NUM> to remote UE <NUM> along one or multiple paths. In this disclosure, these paths are named as paging paths. First, relay UE election methods are disclosed for enabling or disabling the relay function of a relay capable UE to act as a UE-to-NW relay <NUM> or UE-to-UE relay <NUM> for paging message as associated with Relay UE election. A paging path can be established between remote UE <NUM> and gNB <NUM> before gNB <NUM> sends out a paging message to remote UE <NUM> as associated with Paging path established. Methods are disclosed about how a paging message may be propagated from gNB <NUM> to remote UE <NUM> via an established paging path as associated with Paging propagation. Due to the topology changes caused by mobility and relay UE election change, remote UE <NUM>, UE-to-UE relays <NUM>, or UE-to-NW relays <NUM> in the network need to dynamically maintain the paging path between remote UE <NUM> and gNB <NUM> as associated with Paging Path Maintenance and Reachability Management.

In the network, some UEs support relay function to relay paging message and some do not due to their hardware and software capability. However, for UEs that support relay function, the relay function may not be enabled or not be elected to relay paging message. A UE becomes a relay UE when its relay function is enabled. To address issue <NUM> in in the problem statement, relay UE election methods are disclosed for enabling or disabling the relay function of a relay capable UE to act as a UE-to-NW relay <NUM> or UE-to-UE relay <NUM> for paging message.

A UE can enable and disable its relay function itself based on its status (e.g., capacity). For example, if the battery power of the UE is below a pre-configured threshold, the UE can disable its relay function. If a UE has a Uu interface with gNB <NUM>, the UE can enable its relay function and self-elects as a UE-to-NW relay UE <NUM>. If a UE does have a Uu interface with gNB <NUM>, the UE can enable its relay function and self-elects as a UE-to-UE relay <NUM>. If a relay UE is willing to serve as a relay UE for new neighbor UEs, it may periodically broadcast its relay context information as listed in Table <NUM> to its neighbors. Otherwise, based on its status, a relay UE can stop broadcasting its relay context information to its neighbors. For example, if the number of UEs that select the relay UE as relay is larger than a pre-configured threshold, the UE can stop broadcast its relay context information to its neighbors. When a UE receives a relay context information from a neighbor relay UE, it should know the neighbor relay UE is willing to serve as a relay UE. Note that when the relay function on a UE is disabled, the UE may send a stop relaying request to each UE that selects it as a relay UE, to its neighbor UEs that select the UE as a relay UE, or to all neighbor of the UE that the UE stops serving as relay UE. A relay UE may not send its relay context information until it receives a request from its neighbor UE.

A UE can enable and disable its relay function based on number of relay UE in its vicinity. For example, a UE can enable its relay function if there is no relay UE that broadcasts relay context information in its vicinity. A UE can disable its relay function if it receives relay context information from its neighbors. A relay UE may enable or disable broadcasting its relay context information based on number of relay UEs in its vicinity. For example, a UE can enable broadcasting if there is no relay UE that broadcasts relay context information in its vicinity. A UE can disable broadcasting if it receives relay context information from its neighbors.

A UE can enable and disable its relay function configured by gNB <NUM> as shown in <FIG> illustrates an exemplary Relay UE election and configuration by gNB. At step <NUM>, relay UE <NUM> may receive a relay configuration request from gNB <NUM>. At step <NUM>, based on the information (e.g., context information) of the relay configuration request of step <NUM>, configuring a relay parameter. At step <NUM>, sending a relay configuration response to gNB <NUM>. gNB <NUM> can send a relay configuration request to enable or disable the relay function, enable or disable the relay UE broadcasting its relay context information, based on criteria, such as the UE's location, beam direction, capability, traffic load or based on network requirement and policies via a dedicated message. gNB <NUM> can send criteria for a UE to enable or disable the relay function, enable or disable the relay UE broadcasting its relay context information, that the UE may use to determine whether to disable or enable. The relay UE may confirm or refuse the relay configuration request in the request.

A paging may be sent by gNB <NUM> and forwarded by the UE-to-NW relay <NUM> and zero or more UE-to-UE relays <NUM> to remote UE <NUM>. A paging path can be established between remote UE <NUM> and gNB <NUM> before gNB <NUM> sends out a paging message to remote UE <NUM>. To address issue <NUM>, issue <NUM>, or issue <NUM> in the problem statement, methods are disclosed for establishing one or multiple paging paths between gNB <NUM> or remote UE <NUM>. In the first disclosed method described (e.g., Discovery based Paging Path Establishment), a paging path discovery procedure may be triggered by remote UE <NUM> for gNB <NUM> to discover multiple candidate paging paths between remote UE <NUM> and gNB <NUM>. gNB <NUM> may then select and configure the adaptation layer of the UE-to-NW Relay <NUM> and zero or more UE-to-UE relays <NUM> that forward the paging along the paging path. In another disclosed method associated with Paging Path Establishment over Existing Paging Path, remote UE <NUM> may select one of relay UEs that has established one or multiple paging paths to gNB <NUM>, and may then establish its paging path following the paging path of the relay UE by configuring the adaptation layer of relay UEs on the paging path.

In the discovery-based paging path establishment method, a paging path discovery procedure may be triggered by remote UE <NUM> for gNB <NUM> to discover multiple candidate paging paths between remote UE <NUM> and gNB <NUM> as associated with paging path discovery procedure. Then gNB <NUM> may select one or more paging paths and establish the paging path via configuring relay UEs on the path as associated with the paging path configuration procedure.

A paging path discovery procedure is disclosed for gNB <NUM> to discover multiple candidate paging paths between remote UE <NUM> and gNB <NUM> as shown in <FIG>. remote UE <NUM> triggers the procedure by sending (e.g., at step <NUM>) a paging path discovery request to gNB <NUM>. The paging path discovery request is forward by one or multiple relay UEs to gNB <NUM> (e.g., step <NUM> - step <NUM>). Thus, gNB <NUM> can discover multiple candidate paging paths between remote UE <NUM> and gNB <NUM>. gNB <NUM> may select one or multiple paging paths at the end of the procedure based on several criteria (e.g., step <NUM>).

At step <NUM>, a discovery procedure may be executed between remote UE <NUM> and relay <NUM>. Remote UE <NUM> and the relay UE <NUM> may discover each other via the discovery procedure. During the discovery procedure, relay UE <NUM> may broadcast or transmit its relay context information as shown in Table <NUM>.

At step <NUM>, a PC5 connection may be established between remote UE <NUM> and relay <NUM>. Remote UE <NUM> and the Relay UE <NUM> may establish a PC5 connection after the discovery. Remote UE <NUM> may further collect relay context information of relay UE <NUM>, e.g., the link quality between relay UE <NUM>, Sidelink (SL) DRX cycle of relay UE <NUM>.

At step <NUM>, relay <NUM> receives a paging path discovery request from remote UE <NUM>. Remote UE <NUM> sends a paging path discovery request message to relay UEs discovered during step <NUM>. Remote UE <NUM> may send the message using broadcast to all relay UEs within broadcast communication range or using unicast to each discovered relay UE <NUM>. The paging path discovery request message may include but not limited to information shown in Table <NUM>.

At step <NUM>, relay <NUM> determines if it should act as a paging relay for remote UE <NUM>. When relay UE <NUM> receives a paging path discovery request message, it checks whether to serve as a paging relay for the remote UE and forward this paging message to the gNB based on the criteria, such as described in the following examples. In an example, there may be forwarding if gNB ID in the message is the same as gNB <NUM> that the relay UE <NUM> communicates with or gNB ID field is not specified. In an example, there may be forwarding if gNB ID in the message is the same as gNB <NUM> that relay UE <NUM> communicates to or the gNB ID field is not specified. In an example, there may be forwarding if relay UE <NUM> has the capability to serve as a paging relay. In an example, there may be forwarding if relay tier in the message is larger than the tier of relay UE <NUM>. The relay tier of a UE is number of hops the UE is away from the gNB. For example, the relay tier is <NUM> for a UE-to-NW relay UE since UE-to-NW relay is only <NUM> hop away from gNB. In another example, the relay tier is <NUM> for relay UE <NUM> shown in <FIG> since the UE-to-UE relay is <NUM> hops away from gNB. In an example, there may be forwarding if relay UE <NUM> has never received the message with the same sequence number originated from the same remote UE <NUM>.

If the relay UE <NUM> forwards the message, relay UE <NUM> may insert its UE ID appended in paging path discovery request message. The ID of relay UE <NUM> may be a AS layer ID or a network ID.

At step <NUM>, relay <NUM> may send a paging path discovery request to relay <NUM>. Relay UE <NUM> forwards the paging path discovery request message towards gNB <NUM>. Relay UE <NUM> may send the message using broadcast to relay UEs within the broadcast communication range. Alternatively, relay UE <NUM> may send the message using unicast to each relay UE it has a PC5 connection. Relay UE <NUM> may only send to another relay UE that connects with the same gNB <NUM> as indicated in the paging path discovery message, and the tier number of another UE is smaller than its own tier number.

At step <NUM>, relay <NUM> determines whether to act as a paging relay for remote UE <NUM>. Relay UE <NUM> checks whether to serve as a paging relay for remote UE <NUM> or forward this paging message to gNB <NUM> the same as step <NUM>.

At step <NUM>, relay <NUM> sends a paging path discovery request to gNB <NUM>. Relay UE <NUM> forwards the paging path discovery request message to gNB <NUM> since it has a direct connection with gNB <NUM>.

At step <NUM>, gNB <NUM> selects the paging path for remote UE <NUM>. The gNB <NUM> may receive multiple paging path discovery requests sent by the same remote UE <NUM> with the same sequence number, and gNB <NUM> may select one of the multiple paging paths for remote UE <NUM>.

Paging path configuration procedures are disclosed for a gNB <NUM> to establish one or multiple paging paths between remote UE <NUM> and gNB <NUM>. gNB <NUM> triggers the procedure after selecting one of multiple paging paths for remote UE <NUM>.

In the first disclosed procedure as shown in <FIG>, gNB <NUM> sends a paging path discovery response to remote UE <NUM>. The discovery response may include the full paging path information and may be forwarded via all or some of relay UEs <NUM> on the path. When relay UE <NUM> receives a paging path discovery response, relay UE <NUM> may configure its adaptation layer in order to forward a paging message from gNB <NUM> to remote UE <NUM> in the future.

With continued reference to <FIG>, at step <NUM>, gNB <NUM> sends a paging path discovery response to UE-to-NW relay <NUM> on the paging path. The message may include but not limited to the information shown in Table <NUM>.

At step <NUM>, UE-to-NW relay UE <NUM> r uses information received in the message of step <NUM> to configure its adaptation layer to receive and forward paging messages for remote UE <NUM> in the future. If UE-to-Network Relay UE <NUM> monitors remote UE's <NUM> PO in addition to its own PO, UE-to-Network Relay UE <NUM> extracts the parameters to calculate the paging occasion of remote UE <NUM>. UE-to-NW Relay UE <NUM> should also extract information about the next relay on the paging path. The information may be stored associated with remote UE ID or paging path ID. Thus, UE-to-NW Relay UE <NUM> can know which relay to forward the paging message in the future.

At step <NUM>, UE-to-NW Relay UE <NUM> may forward the paging path discovery response message to the next relay UE (e.g., relay UE <NUM>) on the paging path. UE-to-NW relay <NUM> may remove the parameter to calculate the paging occasion and DRX of remote UE <NUM> field in the paging path discovery response message before forwarding the message. Alternatively, UE-to-NW relay <NUM> may add the SL DRX configuration for the next hop relay UE about which slot to receiving paging messages in the future.

At step <NUM>, relay UE <NUM> receives the paging path discovery response and uses information in the message to configure its adaptation layer to receive or forward paging messages for remote UE <NUM> in the future. Relay UE <NUM> should extract information about the next relay on the paging path. The information may be stored associated with remote UE ID or paging path ID. Thus, relay UE <NUM> can know which relay to forward the paging message in the future. Relay UE <NUM> may add the SL DRX information for remote UE <NUM> about which slot to receiving paging message in the future.

At step <NUM>, relay UE <NUM> forwards the paging path discovery response message to remote UE <NUM>. After receiving the message, the remote UE establishes a paging path from the gNB. Remote UE <NUM> stores the ID of UE-to-NW relay UE <NUM>, the paging path ID, or the ID of relay UE that forwards the paging message to it in the future. Remote UE <NUM> may configure its DRX based on the SL DRX information in the message of step <NUM>.

<FIG> provides an exemplary hop by hop paging path configuration. In the second disclosed procedure, gNB <NUM> sends a paging path configuration message to each relay UE on the paging path and configures the adaptation layer. After configuring each relay UE on the paging path, gNB <NUM> sends a paging path discovery response direct to remote UE <NUM>.

At step <NUM>, gNB sends the paging path configuration message to UE-to-NW relay <NUM> on the paging path. The message may include but not limited to information shown in Table <NUM>.

At step <NUM>, UE-to-NW relay UE <NUM> receives the paging path configuration message and uses information in the message to configure the adaptation layer of UE-to-NW relay UE <NUM> to receive and forward paging messages for remote UE <NUM> in the future. If UE-to-Network Relay UE <NUM> monitors the PO of remote UE <NUM> in addition to its own PO, UE-to-NW relay UE <NUM> extracts the parameters to calculate the paging occasion of remote UE <NUM>. UE-to-NW relay UE <NUM> should also exact information about the next relay on the paging path. The information is stored associated with remote UE ID or paging path ID. Thus, UE-to-NW relay UE <NUM> can know which relay to forward the paging message in the future.

At step <NUM>, gNB <NUM> sends the paging path configuration message to the next relay UE <NUM> on the paging path. The message may include but not limited to information shown in Table <NUM>.

At step <NUM>, relay UE <NUM> uses information in the message of step <NUM> to configure its adaptation layer to receive or forward paging messages for remote UE <NUM> in the future. Relay UE <NUM> needs to extract information about the next relay on the paging path. The information may be stored associated with remote UE ID or paging path ID. Thus, relay UE <NUM> can know which relay to forward the paging message in the future.

At step <NUM>, gNB <NUM> sends a paging path discovery response message to remote UE 101on the paging path. The message may include but not limited to information shown in Table <NUM>. After receiving the message, remote UE <NUM> may establish a paging path from the gNB. Remote UE may store the ID of UE-to-NW relay UE <NUM>, the paging path ID, or the ID of relay UE <NUM> that forwards the paging message to it in the future.

In this paging path establishment method, remote UE <NUM> selects one or more relay UEs that have established one or more paging paths to gNB <NUM>, and then establishes its paging paths along the paging paths of the relay UE <NUM> by configuring the adaptation layer of UE-to-UE Relays and the UE-to-NW Relay on the paging path as shown in <FIG>. In this method, one or more neighbor relay UEs have been established a paging path from gNB <NUM>.

At step <NUM>, a paging path has been established. At step <NUM>, remote UE <NUM> and relay UE <NUM> discover each other via a discovery procedure. During the discovery procedure, relay UE <NUM> may broadcast or transmit its relay context information as shown in Table <NUM>.

At step <NUM>, remote UE <NUM> and the relay UE <NUM> may establish a PC5 connection after the discovery. Remote UE <NUM> may further collect information of relay UE <NUM>, e.g. the link quality between relay UE <NUM>, SL DRX cycle of relay UE202.

At step <NUM>, based on the discovered information, remote UE <NUM> selects one or more relay UEs that has established a paging path to gNB <NUM>, and then sends a paging path establishment request message to relay UE <NUM>. The paging path establishment request message may include but not limited to information shown in Table <NUM>.

At step <NUM>, when relay UE <NUM> receives a paging path establishment request message, relay UE <NUM> determines whether to serve as a paging relay for remote UE <NUM> or allow remote UE <NUM> to share the same paging paths. If relay UE <NUM> determines to serve as a paging relay for remote UE <NUM> or allow remote UE <NUM> to share the same paging paths, relay UE <NUM> configures its adaptation layer to receive the paging message or forward the paging message to remote UE <NUM>.

At step 265a, relay UE <NUM> forwards the paging path establishment request message towards gNB <NUM> along its paging path.

At step 265b, relay UE <NUM> sends a paging path establishment response to indicate whether to serve as a paging relay for the remote UE or allow the remote UE to share the same paging paths.

At step <NUM>, relay UE <NUM> configures its adaptation layer to receive and forward the paging message to remote UE <NUM>. When relay <NUM> in <FIG> receives a paging message to remote UE <NUM>, relay <NUM> forwards to relay <NUM>. If relay UE is UE-to-NW relay UE <NUM> and monitors the PO of remote UE <NUM> in addition to PO of relay UE <NUM>, relay UE <NUM> extracts the parameters to calculate the paging occasion of remote UE <NUM> in the request. If UE-to-NW relay <NUM> cannot know the paging occasion based on the information in the paging path establishment request, relay <NUM> sends the paging path establishment request to gNB <NUM> to obtain the paging occasion of remote UE <NUM>. Alternatively, if UE-to-NW relay <NUM> monitors its own PO only and paging for remote UE <NUM> is also sent in the UE-to-Network Relay UE's PO, relay <NUM> forwards the paging path establishment request to gNB <NUM> to inform gNB <NUM>.

At step <NUM>, relay UE <NUM> forwards the paging path establishment request message to gNB <NUM> since it has a direct connection with gNB <NUM>.

At step <NUM>, if UE-to-NW relay UE <NUM> monitors the PO of remote UE <NUM> in addition to its own PO, gNB <NUM> sends a response to UE-to-NW relay UE <NUM> with the parameters to calculate the paging occasion of the remote UE <NUM>. Alternatively, if UE-to-NW relay <NUM> monitors its own PO only and paging for remote UE <NUM> is also sent in UE-to-Network Relay UE's PO, gNB <NUM> updates the paging configuration of remote UE <NUM> and sends the paging using its UE-to-NW relay PO.

At step <NUM>, gNB <NUM> sends a response to UE-to-NW relay UE <NUM> with the parameters to calculate the paging occasion of remote UE <NUM>. The gNB <NUM> may also include the UE_ID, or the I-RNTI-Value of remote UE <NUM> in the response.

Methods are disclosed with regard to how a paging message is propagated from a gNB to a remote UE via an established paging path. In the first disclosed method, UE-to-NW Relay UE <NUM> monitors the PO of remote UE <NUM> in addition to its own PO as shown in <FIG>. In the paging message sent from gNB <NUM> at step <NUM>, the paging UE identity field in the paging record is the ID of remote UE <NUM> or the ID of the paging path associated with remote UE <NUM>. Upon receiving the paging message, for each of paging record, if the UE Identity in the paging record matches the UE identity of remote UE <NUM> that UE-to-NW relay <NUM> monitors, UE-to-NW relay <NUM> forwards (see step <NUM>) the paging message to the next relay UE, e.g. relay <NUM> over the Sidelink. At step <NUM>, the adaptation layer of relay <NUM> forwards the paging message to remote UE <NUM>.

In the second disclosed method, the UE-to-NW relay monitors its own PO only and paging for the remote UE is also sent in the UE-to-Network Relay UE's PO as shown in <FIG>. At step <NUM>, in the paging message sent from gNB <NUM>, the paging UE identity field in the paging record may be the ID of UE-to-NW relay <NUM>, an additional field is added in the paging record to indicate the destination UE identity of the paging message, e.g. identity of remote UE <NUM>. Alternatively, in the paging message sent from gNB <NUM>, the UE identity field in the paging record may be the ID of the destination UE, e.g. identity of remote UE <NUM>. Upon receiving the paging message, for each of paging record, if the destination UE Identity in the paging record matches the UE identity of remote UE <NUM> that UE-to-NW relay <NUM> monitors, UE-to-NW relay <NUM> forwards (see step <NUM>) the paging message to the next relay UE, e.g. relay <NUM> over the sidelink. Similarly, at step <NUM>, the adaptation layer of relay <NUM> forwards the paging message to remote UE <NUM>. In another alternative, in the paging message sent from gNB <NUM> at step <NUM>, the paging UE identity field in the paging record may be the ID of UE-to-NW relay <NUM> and no additional field is added in the paging record to indicate the destination UE identity of the paging message, e.g. identity of remote UE <NUM>. Upon receiving the paging message, UE-to-NW relay <NUM> forwards (see step <NUM>) the paging message to each remote UE it monitors. In each forwarding, UE-to-NW relay <NUM> inserts the identity of remote UE <NUM> and forwards the paging message to the next relay UE, e.g. relay <NUM> over the sidelink. Similarly, the adaptation layer of relay <NUM> forwards (see step <NUM>) the paging message to the remote UE.

To address issue <NUM> and <NUM> of the problem statement, methods are disclosed that the remote UE, UE-to-UE relays and UE-to-NW relays in the network may dynamically maintain the paging path between the remote UE and gNB when the topology changes. Disclosed are exemplary scenarios that a paging path is changed. In a first scenario, remote UE <NUM> selects a new relay UE and establishes a new paging path to gNB <NUM>. In the second scenario, one of relay UEs on the paging path of remote UE <NUM> selects a new relay UE and establishes a new paging path to gNB <NUM>. In this scenario, the paging path of remote UE <NUM> also should be updated. A number of events may trigger the UE for the paging path reselection, based on the change of status of the sidelink, e. g, signal quality of the link, and the status of neighbor relay UEs, e.g. a neighbor relay UE is fewer hops away from gNB or has more sidelink capacity, or lighter load, etc..

The procedure for a remote UE to select a new relay UE and establish a new relay path is shown in <FIG>. In <FIG>, remote UE <NUM> at step <NUM> has established a paging path via relay <NUM> and intends to establish a new paging path via relay <NUM>. The procedure is similar to the paging path establishment procedure associated with Paging Path Establishment over Existing Paging Path. When remote UE <NUM> discovers a new relay UE, e.g. relay <NUM>, relay UE <NUM> can obtain the ID of UE-to-NW relay UE <NUM> associated with relay <NUM> in step <NUM>. In the scenario that UE-to-NW relay <NUM> associated with relay <NUM> is the same as UE-to-NW relay <NUM> on its previous paging path, remote UE <NUM> may not need to include its parameter to calculate the paging occasion and DRX in the paging path establishment request in step <NUM>. In this scenario, UE-to-NW relay <NUM> does not need to send a paging path establishment request to gNB <NUM> if it still has the parameter to calculate the paging occasion and DRX of remote UE <NUM> as in step <NUM>. Step <NUM> is the same as step <NUM> in <FIG>. Step <NUM>-<NUM> are the same as step <NUM>-<NUM> in <FIG>. Step <NUM>-<NUM> are the same as step <NUM>-<NUM> in <FIG>.

The procedure when one of relay UEs on the paging path of the remote UE selects a new relay UE is shown in <FIG>. In <FIG>, remote UE <NUM> has established, at a first period, a paging path via relay <NUM> and relay <NUM> intends, at a second period, to establish a new paging path via relay <NUM>. Relay <NUM> should establish a new paging path to gNB <NUM>. The procedure (e.g., <FIG>) is similar to the paging path establishment procedure associated with Paging Path Establishment over Existing Paging Path (e.g., <FIG>). During the paging path establishment procedure, relay <NUM> sends the paging path establishment request at step <NUM> to all relay UEs on its paging path, e.g. relay <NUM> and UE-to-NW relay <NUM>, to re-establish paging path for all UEs that it forwards paging message to. For example, in step <NUM> relay <NUM> indicates in the paging path establishment request that a paging path also needs to be re-established for remote UE <NUM>. Upon receiving the message of <NUM>, relay <NUM> configures its adaptation layer (at step <NUM>) to forward paging for both remote UE <NUM> and relay <NUM> (step 305a and step 305b). Similarly, when relay <NUM> forwards the paging path establishment request to UE-to-NW relay in step 305a, relay 207indicates that a paging path also needs to be re-established for remote UE <NUM> and relay <NUM>. Upon receiving the message, UE-to-NW relay <NUM> configures (at step 306a) its adaptation layer to forward paging for both remote UE <NUM> and relay <NUM>. If UE-to-NW relay <NUM> on the paging path is changed and option <NUM> approach (e.g., <FIG>) is used, the paging path establishment also includes the parameter to calculate the paging occasion and DRX of relay <NUM> and remote UE <NUM> in the paging path establishment. If UE-to-NW relay <NUM> does not know the parameter to calculate the paging occasion and DRX of relay <NUM> or remote UE <NUM>, relay <NUM> can send requests to relay <NUM>, remote UE <NUM>, or gNB <NUM> to obtain this information. If the UE-to-NW relay <NUM> on the paging path is changed and option <NUM> approach (e.g., <FIG>) is used, UE-to-NW relay <NUM> forwards the paging path establishment request at step <NUM> to gNB <NUM> that the paging for remote UE <NUM> should be sent in the new UE-to-Network Relay UE's PO. If the UE-to-NW relay <NUM> on the paging path is changed, the relay <NUM> needs to update new paging path information to the UEs that it forwards paging message to. For example, relay <NUM> informs remote UE <NUM> about the information of the new UE-to-NW relay <NUM>. Those steps that are not explicitly called out are the same as steps in <FIG>.

A remote UE should maintain the paging path by periodically sending path updates. During the paging path establishment, a paging path update timer may be configured at remote UE <NUM> by gNB <NUM> or relay UEs on the paging path. The paging path update timer may be smaller than the periodical registration update timer and RAN Notification Area update of the UE-to-NW relay associated with the remote UE. Upon the paging path update timer expiring, remote UE <NUM> sends a paging path update at step <NUM> towards gNB <NUM> to update the reachability of the network as shown in <FIG>. The paging path update may include the ID of remote UE <NUM> or paging path ID. When a relay UE on the path, e.g. relay <NUM>, receives the paging path update from remote UE <NUM>, relay UE <NUM> knows remote UE can still be reached via the page path and reset the timer associated the paging path of remote UE <NUM> as shown in step <NUM>. If relay UE <NUM> is not the UE-to-NW relay <NUM>, relay <NUM> forwards the paging path update to the next relay towards gNB <NUM> as in step <NUM>. Relay UE <NUM> may also piggy back (e.g., insert) its UE ID or paging path ID when forwarding the paging path to the next relay UE on the paging path. In this scenario, the paging path update may include UE reachability information of remote UE <NUM> or relay <NUM>. When the next relay UE on the paging path receives the message, e.g. Relay <NUM>, it extracts the reachability information and knows remote UE <NUM> and relay <NUM> can still be reached via the page path and reset the timer associated the paging path of remote UE <NUM> and relay <NUM> as shown in step <NUM>. If relay UE <NUM> is the UE-to-NW relay <NUM> of remote UE <NUM>, relay <NUM> sending an RNA update or registration update to gNB <NUM> depends on its RRC state (see step <NUM>). Further explaining step <NUM>, Note that since remote UE <NUM> does not have a direct link with gNB <NUM>, the RRC state of remote UE <NUM> may be the same with UE-to-NW relay <NUM> on its paging path, and UE-to-NW relay fulfills the RNA update and registration update on behalf of the remote UE <NUM> and all UEs it forwards paging message to. At step <NUM>, fulfill RNA update or registration update.

<FIG> illustrates an exemplary method for paging UE. As disclosed herein, it is contemplated that subject matter associated with other FIGs, such as <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, Table <NUM>, Table <NUM>, or the like may be combined.

At step <NUM>, a first device (UE-to-UE relay <NUM>) may enable or disable the relay function for relaying paging message. A trigger to enable may be a self-initiated request or a request from an external physical or virtual device. The request may include configurations for serving as a paging relay or the configurations may be obtained after the determination of step <NUM>. The configurations may include the paging occasion or the parameter to calculate paging occasion for the second device, an indication of the next device to forward the paging message toward. For example, see Table <NUM> or Table <NUM>.

At step <NUM>, determine whether to serve as a paging relay (e.g., enable or disable relay function) for a second device (e.g., UE <NUM>). Step <NUM> may be triggered by the request of step <NUM> or another request. The determination may be based on status (e.g., capacity). For example, if the battery power of the UE is below a pre-configured threshold, the UE can disable its relay function. The determination may be based on proximity. For example, whether or not there is a relay UE that broadcasts relay context information in the first device's vicinity, such as within threshold radial distance (e.g., within <NUM> feet). The determination may be based on analysis of relay context information (e.g., one or combination of relay context information of Table <NUM>). For example, detection of a particular TrackingAreaCode may help determine whether to disable or enable paging relay function. The determination may be based on analysis of criteria received from the second device. At step <NUM>, the first device may monitor a paging occasion based on information of a second device (e.g., UE-to-NW relay <NUM> or UE <NUM>). This information may be received from the second device, preconfigured, or the like. At step <NUM>, if the first device determines and also is enabled as a paging relay, the first device may receive and process a paging message from a third device (e.g., UE-to-NW relay <NUM> or gNB <NUM>). At step <NUM>, the first device may forward the paging message from one or more other devices (e.g., the third device). At step <NUM>, the first device may maintain (e.g., update) the status as paging relay for the second device. Other devices (e.g., the third device and second device) may be sent messages with an update of the status. The paging path may be updated based on a detection of a topology change or threshold signal quality, among other things. The first device may serve as paging relay or disable such function. The second device may be a remote UE (e.g., UE <NUM>). The third device may be a base station.

It is understood that the entities performing the steps illustrated herein may be logical entities. The steps may be stored in a memory of, and executing on a processor of, a device, server, or computer system such as those illustrated in <FIG> or <FIG>. Skipping steps, combining steps, or adding steps between exemplary methods disclosed herein (e.g., <FIG>) is contemplated. Table <NUM> provides abbreviations and definitions for subject matter herein.

<FIG> illustrates an exemplary display (e.g., graphical user interface) that may be generated based on the methods, systems, and devices of methods and apparatus for paging a remote UE, as discussed herein. Display interface <NUM> (e.g., touch screen display) may provide text in block <NUM> associated with methods and apparatus for paging remote UE, such as RRC related parameters. Progress of any of the steps (e.g., sent messages or success of steps) discussed herein may be displayed in block <NUM>. In addition, graphical output <NUM> may be displayed on display interface <NUM>. Graphical output <NUM> may be the topology of the devices implementing the methods, systems, and devices for paging remote UEs, a graphical output of the progress of any method or systems discussed herein, or the like.

The 3rd Generation Partnership Project (3GPP) develops technical standards for cellular telecommunications network technologies, including radio access, the core transport network, and service capabilities - including work on codecs, security, and quality of service. Recent radio access technology (RAT) standards include WCDMA (commonly referred as <NUM>), LTE (commonly referred as <NUM>), LTE-Advanced standards, and New Radio (NR), which is also referred to as "<NUM>". 3GPP NR standards development is expected to continue and include the definition of next generation radio access technology (new RAT), which is expected to include the provision of new flexible radio access below <NUM>, and the provision of new ultra-mobile broadband radio access above <NUM>. The flexible radio access is expected to consist of a new, non-backwards compatible radio access in new spectrum below <NUM>, and it is expected to include different operating modes that may be multiplexed together in the same spectrum to address a broad set of 3GPP NR use cases with diverging requirements. The ultra-mobile broadband is expected to include cmWave and mmWave spectrum that will provide the opportunity for ultra-mobile broadband access for, e.g., indoor applications and hotspots. In particular, the ultra-mobile broadband is expected to share a common design framework with the flexible radio access below <NUM>, with cmWave and mmWave specific design optimizations.

3GPP has identified a variety of use cases that NR is expected to support, resulting in a wide variety of user experience requirements for data rate, latency, and mobility. The use cases include the following general categories: enhanced mobile broadband (eMBB) ultra-reliable low-latency Communication (URLLC), massive machine type communications (mMTC), network operation (e.g., network slicing, routing, migration and interworking, energy savings), and enhanced vehicle-to-everything (eV2X) communications, which may include any of Vehicle-to-Vehicle Communication (V2V), Vehicle-to-Infrastructure Communication (V2I), Vehicle-to-Network Communication (V2N), Vehicle-to-Pedestrian Communication (V2P), and vehicle communications with other entities. Specific service and applications in these categories include, e.g., monitoring and sensor networks, device remote controlling, bi-directional remote controlling, personal cloud computing, video streaming, wireless cloud-based office, first responder connectivity, automotive ecall, disaster alerts, real-time gaming, multi-person video calls, autonomous driving, augmented reality, tactile internet, virtual reality, home automation, robotics, and aerial drones to name a few. All of these use cases and others are contemplated herein.

<FIG> illustrates an example communications system <NUM> in which the methods and apparatuses of for paging a remote UE, such as the systems and methods illustrated in <FIG> described and claimed herein may be used. The communications system <NUM> may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, 102e, 102f, or <NUM> (which generally or collectively may be referred to as WTRU <NUM> or WTRUs <NUM>). The communications system <NUM> may include, a radio access network (RAN) <NUM>/<NUM>/<NUM>/103b/104b/105b, a core network <NUM>/<NUM>/<NUM>, a public switched telephone network (PSTN) <NUM>, the Internet <NUM>, other networks <NUM>, and Network Services <NUM>. Network Services <NUM> may include, for example, a V2X server, V2X functions, a ProSe server, ProSe functions, IoT services, video streaming, or edge computing, etc..

It will be appreciated that the concepts disclosed herein may be used with any number of WTRUs, base stations, networks, or network elements. Each of the WTRUs 102a, 102b, 102c, 102d, 102e, 102f, or102g may be any type of apparatus or device configured to operate or communicate in a wireless environment. Although each WTRU 102a, 102b, 102c, 102d, 102e, 102f, or <NUM> may be depicted in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, or <FIG> as a hand-held wireless communications apparatus, it is understood that with the wide variety of use cases contemplated for <NUM> wireless communications, each WTRU may comprise or be embodied in any type of apparatus or device configured to transmit or receive wireless signals, including, by way of example only, user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a tablet, a netbook, a notebook computer, a personal computer, a wireless sensor, consumer electronics, a wearable device such as a smart watch or smart clothing, a medical or eHealth device, a robot, industrial equipment, a drone, a vehicle such as a car, bus, truck, train, or airplane, and the like.

The communications system <NUM> may also include a base station 114a and a base station 114b. In the example of <FIG>, each base stations 114a and 114b is depicted as a single element. In practice, the base stations 114a and 114b may include any number of interconnected base stations or network elements. Base stations 114a may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, and 102c to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, Network Services <NUM>, or the other networks <NUM>. Similarly, base station 114b may be any type of device configured to wiredly or wirelessly interface with at least one of the Remote Radio Heads (RRHs) 118a, 118b, Transmission and Reception Points (TRPs) 119a, 119b, or Roadside Units (RSUs) 120a and 120b to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, other networks <NUM>, or Network Services <NUM>. RRHs 118a, 118b may be any type of device configured to wirelessly interface with at least one of the WTRUs <NUM>, e.g., WTRU 102c, to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, Network Services <NUM>, or other networks <NUM>.

TRPs 119a, 119b may be any type of device configured to wirelessly interface with at least one of the WTRU 102d, to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, Network Services <NUM>, or other networks <NUM>. RSUs 120a and 120b may be any type of device configured to wirelessly interface with at least one of the WTRU 102e or 102f, to facilitate access to one or more communication networks, such as the core network <NUM>/<NUM>/<NUM>, the Internet <NUM>, other networks <NUM>, or Network Services <NUM>. By way of example, the base stations 114a, 114b may be a Base Transceiver Station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a Next Generation Node-B (gNode B), a satellite, a site controller, an access point (AP), a wireless router, and the like.

The base station 114a may be part of the RAN <NUM>/<NUM>/<NUM>, which may also include other base stations or network elements (not shown), such as a Base Station Controller (BSC), a Radio Network Controller (RNC), relay nodes, etc. Similarly, the base station 114b may be part of the RAN 103b/104b/105b, which may also include other base stations or network elements (not shown), such as a BSC, a RNC, relay nodes, etc. The base station 114a may be configured to transmit or receive wireless signals within a particular geographic region, which may be referred to as a cell (not shown). Similarly, the base station 114b may be configured to transmit or receive wired or wireless signals within a particular geographic region, which may be referred to as a cell (not shown) for methods, systems, and devices of for paging a remote UE, as disclosed herein. Similarly, the base station 114b may be configured to transmit or receive wired or wireless signals within a particular geographic region, which may be referred to as a cell (not shown). Thus, in an example, the base station 114a may include three transceivers, e.g., one for each sector of the cell. In an example, the base station 114a may employ multiple-input multiple output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell.

The base stations 114a may communicate with one or more of the WTRUs 102a, 102b, 102c, or <NUM> over an air interface <NUM>/<NUM>/<NUM>, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface <NUM>/<NUM>/<NUM> may be established using any suitable radio access technology (RAT).

The base stations 114b may communicate with one or more of the RRHs 118a, 118b, TRPs 119a, 119b, or RSUs 120a, 120b, over a wired or air interface 115b/116b/117b, which may be any suitable wired (e.g., cable, optical fiber, etc.) or wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115b/116b/117b may be established using any suitable radio access technology (RAT).

The RRHs 118a, 118b, TRPs 119a, 119b or RSUs 120a, 120b, may communicate with one or more of the WTRUs 102c, 102d, 102e, 102f over an air interface 115c/116c/117c, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115c/116c/117c may be established using any suitable radio access technology (RAT).

The WTRUs 102a, 102b, 102c,102d, 102e, or 102f may communicate with one another over an air interface 115d/116d/117d, such as Sidelink communication, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface 115d/116d/117d may be established using any suitable radio access technology (RAT).

The communications system <NUM> may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN <NUM>/<NUM>/<NUM> and the WTRUs 102a, 102b, 102c, or RRHs 118a, 118b,TRPs 119a, 119b and RSUs 120a, 120b, in the RAN 103b/104b/105b and the WTRUs 102c, 102d, 102e, 102f, may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface <NUM>/<NUM>/<NUM> or 115c/116c/117c respectively using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA) or High-Speed Uplink Packet Access (HSUPA).

In an example, the base station 114a and the WTRUs 102a, 102b, 102c, or RRHs 118a, 118b, TRPs 119a, 119b, or RSUs 120a, 120b in the RAN 103b/104b/105b and the WTRUs 102c, 102d, may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface <NUM>/<NUM>/<NUM> or 115c/116c/117c respectively using Long Term Evolution (LTE) or LTE-Advanced (LTE-A). In the future, the air interface <NUM>/<NUM>/<NUM> or 115c/116c/117c may implement 3GPP NR technology. The LTE and LTE-A technology may include LTE D2D and V2X technologies and interfaces (such as Sidelink communications, etc.). Similarly, the 3GPP NR technology includes NR V2X technologies and interface (such as Sidelink communications, etc.).

The base station 114a in the RAN <NUM>/<NUM>/<NUM> and the WTRUs 102a, 102b, 102c, and <NUM> or RRHs 118a, 118b, TRPs 119a, 119b or RSUs 120a, 120b in the RAN 103b/104b/105b and the WTRUs 102c, 102d, 102e, 102f may implement radio technologies such as IEEE <NUM> (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard <NUM> (IS-<NUM>), Interim Standard <NUM> (IS-<NUM>), Interim Standard <NUM> (IS-<NUM>), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

The base station 114c in <FIG> may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a train, an aerial, a satellite, a manufactory, a campus, and the like, for implementing the methods, systems, and devices for paging a remote UE, as disclosed herein. In an example, the base station 114c and the WTRUs <NUM>, e.g., WTRU 102e, may implement a radio technology such as IEEE <NUM> to establish a wireless local area network (WLAN). similarly, the base station 114c and the WTRUs 102d, may implement a radio technology such as IEEE <NUM> to establish a wireless personal area network (WPAN). In yet another example, the base station 114c and the WTRUs <NUM>, e.g., WTRU 102e, may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, NR, etc.) to establish a picocell or femtocell. As shown in <FIG>, the base station 114cmay have a direct connection to the Internet <NUM>. Thus, the base station 114c may not be required to access the Internet <NUM> via the core network <NUM>/<NUM>/<NUM>.

The RAN <NUM>/<NUM>/<NUM> or RAN 103b/104b/105b may be in communication with the core network <NUM>/<NUM>/<NUM>, which may be any type of network configured to provide voice, data, messaging, authorization and authentication, applications, or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. For example, the core network <NUM>/<NUM>/<NUM> may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, packet data network connectivity, Ethernet connectivity, video distribution, etc., or perform high-level security functions, such as user authentication.

Although not shown in <FIG>, it will be appreciated that the RAN <NUM>/<NUM>/<NUM> or RAN 103b/104b/105b or the core network <NUM>/<NUM>/<NUM> may be in direct or indirect communication with other RANs that employ the same RAT as the RAN <NUM>/<NUM>/<NUM> or RAN 103b/104b/105b or a different RAT. For example, in addition to being connected to the RAN <NUM>/<NUM>/<NUM> or RAN 103b/104b/105b, which may be utilizing an E-UTRA radio technology, the core network <NUM>/<NUM>/<NUM> may also be in communication with another RAN (not shown) employing a GSM or NR radio technology.

The core network <NUM>/<NUM>/<NUM> may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d, 102e to access the PSTN <NUM>, the Internet <NUM>, or other networks <NUM>. The networks <NUM> may include wired or wireless communications networks owned or operated by other service providers. For example, the networks <NUM> may include any type of packet data network (e.g., an IEEE <NUM> Ethernet network) or another core network connected to one or more RANs, which may employ the same RAT as the RAN <NUM>/<NUM>/<NUM> or RAN 103b/104b/105b or a different RAT.

Some or all of the WTRUs 102a, 102b, 102c, 102d, 102e, and 102f in the communications system <NUM> may include multi-mode capabilities, e.g., the WTRUs 102a, 102b, 102c, 102d, 102e, and 102f may include multiple transceivers for communicating with different wireless networks over different wireless links for implementing methods, systems, and devices for paging a remote UE, as disclosed herein. For example, the WTRU <NUM> shown in <FIG> may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114c, which may employ an IEEE <NUM> radio technology.

Although not shown in <FIG>, it will be appreciated that a User Equipment may make a wired connection to a gateway. The gateway maybe a Residential Gateway (RG). The RG may provide connectivity to a Core Network <NUM>/<NUM>/<NUM>. It will be appreciated that many of the ideas included herein may equally apply to UEs that are WTRUs and UEs that use a wired connection to connect with a network. For example, the ideas that apply to the wireless interfaces <NUM>, <NUM>, <NUM> and 115c/116c/117c may equally apply to a wired connection.

<FIG> is a system diagram of an example RAN <NUM> and core network <NUM> that may implement methods, systems, and devices for paging a remote UE, as disclosed herein. As noted above, the RAN <NUM> may employ a UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface <NUM>. As shown in <FIG>, the RAN <NUM> may include Node-Bs 140a, 140b, and 140c, which may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface <NUM>. The Node-Bs 140a, 140b, and 140c may each be associated with a particular cell (not shown) within the RAN <NUM>. The RAN <NUM> may also include RNCs 142a, 142b. It will be appreciated that the RAN <NUM> may include any number of Node-Bs and Radio Network Controllers (RNCs.

As shown in <FIG>, the Node-Bs 140a, 140b may be in communication with the RNC 142a. Additionally, the Node-B 140c may be in communication with the RNC 142b. The Node-Bs 140a, 140b, and 140c may communicate with the respective RNCs 142a and 142b via an Iub interface. The RNCs 142a and 142b may be in communication with one another via an Iur interface. Each of the RNCs 142aand 142b may be configured to control the respective Node-Bs 140a, 140b, and 140c to which it is connected. In addition, each of the RNCs 142aand 142b may be configured to carry out or support other functionality, such as outer loop power control, load control, admission control, packet scheduling, handover control, macrodiversity, security functions, data encryption, and the like.

The core network <NUM> shown in <FIG> may include a media gateway (MGW) <NUM>, a Mobile Switching Center (MSC) <NUM>, a Serving GPRS Support Node (SGSN) <NUM>, or a Gateway GPRS Support Node (GGSN) <NUM>. While each of the foregoing elements are depicted as part of the core network <NUM>, it will be appreciated that any one of these elements may be owned or operated by an entity other than the core network operator.

The MSC <NUM> and the MGW <NUM> may provide the WTRUs 102a, 102b, and 102c with access to circuit-switched networks, such as the PSTN <NUM>, to facilitate communications between the WTRUs 102a, 102b, and 102c, and traditional land-line communications devices.

The SGSN <NUM> and the GGSN <NUM> may provide the WTRUs 102a, 102b, and 102c with access to packet-switched networks, such as the Internet <NUM>, to facilitate communications between and the WTRUs 102a, 102b, and 102c, and IP-enabled devices.

The core network <NUM> may also be connected to the other networks <NUM>, which may include other wired or wireless networks that are owned or operated by other service providers.

<FIG> is a system diagram of an example RAN <NUM> and core network <NUM> that may implement methods, systems, and devices for paging a remote UE, as disclosed herein. As noted above, the RAN <NUM> may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, and 102c over the air interface <NUM>.

The RAN <NUM> may include eNode-Bs 160a, 160b, and 160c, though it will be appreciated that the RAN <NUM> may include any number of eNode-Bs. The eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface <NUM>. For example, the eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

Each of the eNode-Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink or downlink, and the like. As shown in <FIG>, the eNode-Bs 160a, 160b, and 160c may communicate with one another over an X2 interface.

The core network <NUM> shown in <FIG> may include a Mobility Management Gateway (MME) <NUM>, a serving gateway <NUM>, and a Packet Data Network (PDN) gateway <NUM>. While each of the foregoing elements are depicted as part of the core network <NUM>, it will be appreciated that any one of these elements may be owned or operated by an entity other than the core network operator.

The MME <NUM> may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN <NUM> via an S1 interface and may serve as a control node. For example, the MME <NUM> may be responsible for authenticating users of the WTRUs 102a, 102b, and 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, and 102c, and the like. The MME <NUM> may also provide a control plane function for switching between the RAN <NUM> and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.

The serving gateway <NUM> may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN <NUM> via the S1 interface. The serving gateway <NUM> may generally route and forward user data packets to/from the WTRUs 102a, 102b, and 102c. The serving gateway <NUM> may also perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs 102a, 102b, and 102c, managing and storing contexts of the WTRUs 102a, 102b, and 102c, and the like.

The serving gateway <NUM> may also be connected to the PDN gateway <NUM>, which may provide the WTRUs 102a, 102b, and 102c with access to packet-switched networks, such as the Internet <NUM>, to facilitate communications between the WTRUs 102a, 102b, 102c, and IP-enabled devices.

For example, the core network <NUM> may provide the WTRUs 102a, 102b, and 102c with access to circuit-switched networks, such as the PSTN <NUM>, to facilitate communications between the WTRUs 102a, 102b, and 102c and traditional land-line communications devices. For example, the core network <NUM> may include, or may communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the core network <NUM> and the PSTN <NUM>. In addition, the core network <NUM> may provide the WTRUs 102a, 102b, and 102c with access to the networks <NUM>, which may include other wired or wireless networks that are owned or operated by other service providers.

<FIG> is a system diagram of an example RAN <NUM> and core network <NUM> that may implement methods, systems, and devices for paging a remote UE, as disclosed herein. The RAN <NUM> may employ an NR radio technology to communicate with the WTRUs 102a and 102b over the air interface <NUM>. A Non-3GPP Interworking Function (N3IWF) <NUM> may employ a non-3GPP radio technology to communicate with the WTRU 102c over the air interface <NUM>. The N3IWF <NUM> may also be in communication with the core network <NUM>.

The RAN <NUM> may include gNode-Bs 180a and 180b. It will be appreciated that the RAN <NUM> may include any number of gNode-Bs. The gNode-Bs 180a and 180b may each include one or more transceivers for communicating with the WTRUs 102a and 102b over the air interface <NUM>. When integrated access and backhaul connection are used, the same air interface may be used between the WTRUs and gNode-Bs, which may be the core network <NUM> via one or multiple gNBs. The gNode-Bs 180a and 180b may implement MIMO, MU-MIMO, or digital beamforming technology. Thus, the gNode-B 180a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a. It should be appreciated that the RAN <NUM> may employ of other types of base stations such as an eNode-B. It will also be appreciated the RAN <NUM> may employ more than one type of base station. For example, the RAN may employ eNode-Bs and gNode-Bs.

The N3IWF <NUM> may include a non-3GPP Access Point 180c. It will be appreciated that the N3IWF <NUM> may include any number of non-3GPP Access Points. The non-3GPP Access Point 180c may include one or more transceivers for communicating with the WTRUs 102c over the air interface <NUM>. The non-3GPP Access Point 180c may use the <NUM> protocol to communicate with the WTRU 102c over the air interface <NUM>.

Each of the gNode-Bs 180a and 180b may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink or downlink, and the like. As shown in <FIG>, the gNode-Bs 180a and 180b may communicate with one another over an Xn interface, for example.

The core network <NUM> shown in <FIG> may be a <NUM> core network (5GC). The core network <NUM> may offer numerous communication services to customers who are interconnected by the radio access network. The core network <NUM> comprises a number of entities that perform the functionality of the core network. As used herein, the term "core network entity" or "network function" refers to any entity that performs one or more functionalities of a core network. It is understood that such core network entities may be logical entities that are implemented in the form of computer-executable instructions (software) stored in a memory of, and executing on a processor of, an apparatus configured for wireless or network communications or a computer system, such as system <NUM> illustrated in <FIG>.

In the example of <FIG>, the <NUM> Core Network <NUM> may include an access and mobility management function (AMF) <NUM>, a Session Management Function (SMF) <NUM>, User Plane Functions (UPFs) 176a and 176b, a User Data Management Function (UDM) <NUM>, an Authentication Server Function (AUSF) <NUM>, a Network Exposure Function (NEF) <NUM>, a Policy Control Function (PCF) <NUM>, a Non-3GPP Interworking Function (N3IWF) <NUM>, a User Data Repository (UDR) <NUM>. While each of the foregoing elements are depicted as part of the <NUM> core network <NUM>, it will be appreciated that any one of these elements may be owned or operated by an entity other than the core network operator. It will also be appreciated that a <NUM> core network may not consist of all of these elements, may consist of additional elements, and may consist of multiple instances of each of these elements. <FIG> shows that network functions directly connect with one another, however, it should be appreciated that they may communicate via routing agents such as a diameter routing agent or message buses.

In the example of <FIG>, connectivity between network functions is achieved via a set of interfaces, or reference points. It will be appreciated that network functions could be modeled, described, or implemented as a set of services that are invoked, or called, by other network functions or services. Invocation of a Network Function service may be achieved via a direct connection between network functions, an exchange of messaging on a message bus, calling a software function, etc..

The AMF <NUM> may be connected to the RAN <NUM> via an N2 interface and may serve as a control node. For example, the AMF <NUM> may be responsible for registration management, connection management, reachability management, access authentication, access authorization. The AMF may be responsible forwarding user plane tunnel configuration information to the RAN <NUM> via the N2 interface. The AMF <NUM> may receive the user plane tunnel configuration information from the SMF via an N11 interface. The AMF <NUM> may generally route and forward NAS packets to/from the WTRUs 102a, 102b, and 102c via an N1 interface. The N1 interface is not shown in <FIG>.

The SMF <NUM> may be connected to the AMF <NUM> via an N11 interface. Similarly the SMF may be connected to the PCF <NUM> via an N7 interface, and to the UPFs 176a and 176b via an N4 interface. The SMF <NUM> may serve as a control node. For example, the SMF <NUM> may be responsible for Session Management, IP address allocation for the WTRUs 102a, 102b, and 102c, management and configuration of traffic steering rules in the UPF 176a and UPF 176b, and generation of downlink data notifications to the AMF <NUM>.

The UPF 176a and UPF176b may provide the WTRUs 102a, 102b, and 102c with access to a Packet Data Network (PDN), such as the Internet <NUM>, to facilitate communications between the WTRUs 102a, 102b, and 102c and other devices. The UPF 176a and UPF 176b may also provide the WTRUs 102a, 102b, and 102c with access to other types of packet data networks. For example, Other Networks <NUM> may be Ethernet Networks or any type of network that exchanges packets of data. The UPF 176a and UPF 176b may receive traffic steering rules from the SMF <NUM> via the N4 interface. The UPF 176a and UPF 176b may provide access to a packet data network by connecting a packet data network with an N6 interface or by connecting to each other and to other UPFs via an N9 interface. In addition to providing access to packet data networks, the UPF <NUM> may be responsible packet routing and forwarding, policy rule enforcement, quality of service handling for user plane traffic, downlink packet buffering.

The AMF <NUM> may also be connected to the N3IWF <NUM>, for example, via an N2 interface. The N3IWF facilitates a connection between the WTRU 102c and the <NUM> core network <NUM>, for example, via radio interface technologies that are not defined by 3GPP. The AMF may interact with the N3IWF <NUM> in the same, or similar, manner that it interacts with the RAN <NUM>.

The PCF <NUM> may be connected to the SMF <NUM> via an N7 interface, connected to the AMF <NUM> via an N15 interface, and to an Application Function (AF) <NUM> via an N5 interface. The N15 and N5 interfaces are not shown in <FIG>. The PCF <NUM> may provide policy rules to control plane nodes such as the AMF <NUM> and SMF <NUM>, allowing the control plane nodes to enforce these rules. The PCF <NUM>, may send policies to the AMF <NUM> for the WTRUs 102a, 102b, and 102c so that the AMF may deliver the policies to the WTRUs 102a, 102b, and 102c via an N1 interface. Policies may then be enforced, or applied, at the WTRUs 102a, 102b, and 102c.

The UDR <NUM> may act as a repository for authentication credentials and subscription information. The UDR may connect with network functions, so that network function can add to, read from, and modify the data that is in the repository. For example, the UDR <NUM> may connect with the PCF <NUM> via an N36 interface. Similarly, the UDR <NUM> may connect with the NEF <NUM> via an N37 interface, and the UDR <NUM> may connect with the UDM <NUM> via an N35 interface.

The UDM <NUM> may serve as an interface between the UDR <NUM> and other network functions. The UDM <NUM> may authorize network functions to access of the UDR <NUM>. For example, the UDM <NUM> may connect with the AMF <NUM> via an N8 interface, the UDM <NUM> may connect with the SMF <NUM> via an N10 interface. Similarly, the UDM <NUM> may connect with the AUSF <NUM> via an N13 interface. The UDR <NUM> and UDM <NUM> may be tightly integrated.

The AUSF <NUM> performs authentication related operations and connects with the UDM <NUM> via an N13 interface and to the AMF <NUM> via an N12 interface.

The NEF <NUM> exposes capabilities and services in the <NUM> core network <NUM> to Application Functions (AF) <NUM>. Exposure may occur on the N33 API interface. The NEF may connect with an AF <NUM> via an N33 interface and it may connect with other network functions in order to expose the capabilities and services of the <NUM> core network <NUM>.

Application Functions <NUM> may interact with network functions in the <NUM> Core Network <NUM>. Interaction between the Application Functions <NUM> and network functions may be via a direct interface or may occur via the NEF <NUM>. The Application Functions <NUM> may be considered part of the <NUM> Core Network <NUM> or may be external to the <NUM> Core Network <NUM> and deployed by enterprises that have a business relationship with the mobile network operator.

Network Slicing is a mechanism that could be used by mobile network operators to support one or more 'virtual' core networks behind the operator's air interface. This involves 'slicing' the core network into one or more virtual networks to support different RANs or different service types running across a single RAN. Network slicing enables the operator to create networks customized to provide optimized solutions for different market scenarios which demands diverse requirements, e.g. in the areas of functionality, performance and isolation.

3GPP has designed the <NUM> core network to support Network Slicing. Network Slicing is a good tool that network operators can use to support the diverse set of <NUM> use cases (e.g., massive IoT, critical communications, V2X, and enhanced mobile broadband) which demand very diverse and sometimes extreme requirements. Without the use of network slicing techniques, it is likely that the network architecture would not be flexible and scalable enough to efficiently support a wider range of use cases need when each use case has its own specific set of performance, scalability, and availability requirements. Furthermore, introduction of new network services should be made more efficient.

Referring again to <FIG>, in a network slicing scenario, a WTRU 102a, 102b, or 102c may connect with an AMF <NUM>, via an N1 interface. The AMF may be logically part of one or more slices. The AMF may coordinate the connection or communication of WTRU 102a, 102b, or 102c with one or more UPF 176a and 176b, SMF <NUM>, and other network functions. Each of the UPFs 176a and 176b, SMF <NUM>, and other network functions may be part of the same slice or different slices. When they are part of different slices, they may be isolated from each other in the sense that they may utilize different computing resources, security credentials, etc..

For example, the core network <NUM> may include, or may communicate with, an IP gateway, such as an IP Multimedia Subsystem (IMS) server, that serves as an interface between the <NUM> core network <NUM> and a PSTN <NUM>. For example, the core network <NUM> may include, or communicate with a short message service (SMS) service center that facilities communication via the short message service. For example, the <NUM> core network <NUM> may facilitate the exchange of non-IP data packets between the WTRUs 102a, 102b, and 102c and servers or applications functions <NUM>. In addition, the core network <NUM> may provide the WTRUs 102a, 102b, and 102c with access to the networks <NUM>, which may include other wired or wireless networks that are owned or operated by other service providers.

The core network entities described herein and illustrated in <FIG>, <FIG>, <FIG>, or <FIG> are identified by the names given to those entities in certain existing 3GPP specifications, but it is understood that in the future those entities and functionalities may be identified by other names and certain entities or functions may be combined in future specifications published by 3GPP, including future 3GPP NR specifications. Thus, the particular network entities and functionalities described and illustrated in <FIG>, <FIG>, <FIG>, <FIG>, or <FIG> are provided by way of example only, and it is understood that the subject matter disclosed and claimed herein may be embodied or implemented in any similar communication system, whether presently defined or defined in the future.

<FIG> illustrates an example communications system <NUM> in which the systems, methods, apparatuses that implement paging a remote UE, described herein, may be used. Communications system <NUM> may include Wireless Transmit/Receive Units (WTRUs) A, B, C, D, E, F, a base station gNB <NUM>, a V2X server <NUM>, and Road Side Units (RSUs) 123a and 123b. In practice, the concepts presented herein may be applied to any number of WTRUs, base station gNBs, V2X networks, or other network elements. One or several or all WTRUs A, B, C, D, E, and F may be out of range of the access network coverage <NUM>. WTRUs A, B, and C form a V2X group, among which WTRU A is the group lead and WTRUs B and C are group members.

WTRUs A, B, C, D, E, and F may communicate with each other over a Uu interface <NUM> via the gNB <NUM> if they are within the access network coverage <NUM>. In the example of <FIG>, WTRUs B and F are shown within access network coverage <NUM>. WTRUs A, B, C, D, E, and F may communicate with each other directly via a Sidelink interface (e.g., PC5 or NR PC5) such as interface 125a, 125b, or <NUM>, whether they are under the access network coverage <NUM> or out of the access network coverage <NUM>. For instance, in the example of <FIG>, WRTU D, which is outside of the access network coverage <NUM>, communicates with WTRU F, which is inside the coverage <NUM>.

WTRUs A, B, C, D, E, and F may communicate with RSU 123a or 123b via a Vehicle-to-Network (V2N) <NUM> or Sidelink interface 125b. WTRUs A, B, C, D, E, and F may communicate to a V2X Server <NUM> via a Vehicle-to-Infrastructure (V2I) interface <NUM>. WTRUs A, B, C, D, E, and F may communicate to another UE via a Vehicle-to-Person (V2P) interface <NUM>.

<FIG> is a block diagram of an example apparatus or device WTRU <NUM> that may be configured for wireless communications and operations in accordance with the systems, methods, and apparatuses that implement paging a remote UE, described herein, such as a WTRU <NUM> of <FIG>, <FIG>, <FIG>, <FIG>, or <FIG>, or <FIG> (e.g., UEs). As shown in <FIG>, the example WTRU <NUM> may include a processor <NUM>, a transceiver <NUM>, a transmit/receive element <NUM>, a speaker/microphone <NUM>, a keypad <NUM>, a display/touchpad/indicators <NUM>, non-removable memory <NUM>, removable memory <NUM>, a power source <NUM>, a global positioning system (GPS) chipset <NUM>, and other peripherals <NUM>. It will be appreciated that the WTRU <NUM> may include any sub-combination of the foregoing elements. Also, the base stations 114a and 114b, or the nodes that base stations 114a and 114b may represent, such as but not limited to transceiver station (BTS), a Node-B, a site controller, an access point (AP), a home node-B, an evolved home node-B (eNodeB), a home evolved node-B (HeNB), a home evolved node-B gateway, a next generation node-B (gNode-B), and proxy nodes, among others, may include some or all of the elements depicted in <FIG> and may be an exemplary implementation that performs the disclosed systems and methods for paging a remote UE described herein.

The processor <NUM> may perform signal coding, data processing, power control, input/output processing, or any other functionality that enables the WTRU <NUM> to operate in a wireless environment.

The transmit/receive element <NUM> of a UE may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a of <FIG>) over the air interface <NUM>/<NUM>/<NUM> or another UE over the air interface 115d/116d/117d. For example, the transmit/receive element <NUM> may be an antenna configured to transmit or receive RF signals. The transmit/receive element <NUM> may be an emitter/detector configured to transmit or receive IR, UV, or visible light signals, for example. The transmit/receive element <NUM> may be configured to transmit and receive both RF and light signals. It will be appreciated that the transmit/receive element <NUM> may be configured to transmit or receive any combination of wireless or wired signals.

Thus, the WTRU <NUM> may include two or more transmit/receive elements <NUM> (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface <NUM>/<NUM>/<NUM>.

Thus, the transceiver <NUM> may include multiple transceivers for enabling the WTRU <NUM> to communicate via multiple RATs, for example NR and IEEE <NUM> or NR and E-UTRA, or to communicate with the same RAT via multiple beams to different RRHs, TRPs, RSUs, or nodes.

The processor <NUM> of the WTRU <NUM> may be coupled to, and may receive user input data from, the speaker/microphone <NUM>, the keypad <NUM>, or the display/touchpad/indicators <NUM> (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit. The processor <NUM> may also output user data to the speaker/microphone <NUM>, the keypad <NUM>, or the display/touchpad/indicators <NUM>. In addition, the processor <NUM> may access information from, and store data in, any type of suitable memory, such as the non-removable memory <NUM> or the removable memory <NUM>. The processor <NUM> may access information from, and store data in, memory that is not physically located on the WTRU <NUM>, such as on a server that is hosted in the cloud or in an edge computing platform or in a home computer (not shown). The processor <NUM> may be configured to control lighting patterns, images, or colors on the display or indicators <NUM> in response to whether some of the examples described herein are successful or unsuccessful, or otherwise indicate a status of paging a remote UE and associated components. The control lighting patterns, images, or colors on the display or indicators <NUM> may be reflective of the status of any of the method flows or components in the FIG. 's illustrated or discussed herein (e.g., <FIG>, etc.). Disclosed herein are messages and procedures of paging a remote UE. The messages and procedures may be extended to provide interface/API for users to request resources via an input source (e.g., speaker/microphone <NUM>, keypad <NUM>, or display/touchpad/indicators <NUM>) and request, configure, or query paging a remote UE related information, among other things that may be displayed on display <NUM>.

The processor <NUM> may receive power from the power source <NUM>, and may be configured to distribute or control the power to the other components in the WTRU <NUM>. For example, the power source <NUM> may include one or more dry cell batteries, solar cells, fuel cells, and the like.

In addition to, or in lieu of, the information from the GPS chipset <NUM>, the WTRU <NUM> may receive location information over the air interface <NUM>/<NUM>/<NUM> from a base station (e.g., base stations 114a, 114b) or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU <NUM> may acquire location information by way of any suitable location-determination method.

The processor <NUM> may further be coupled to other peripherals <NUM>, which may include one or more software or hardware modules that provide additional features, functionality, or wired or wireless connectivity. For example, the peripherals <NUM> may include various sensors such as an accelerometer, biometrics (e.g., finger print) sensors, an e-compass, a satellite transceiver, a digital camera (for photographs or video), a universal serial bus (USB) port or other interconnect interfaces, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, and the like.

The WTRU <NUM> may be included in other apparatuses or devices, such as a sensor, consumer electronics, a wearable device such as a smart watch or smart clothing, a medical or eHealth device, a robot, industrial equipment, a drone, a vehicle such as a car, truck, train, or an airplane. The WTRU <NUM> may connect with other components, modules, or systems of such apparatuses or devices via one or more interconnect interfaces, such as an interconnect interface that may comprise one of the peripherals <NUM>.

<FIG> is a block diagram of an exemplary computing system <NUM> in which one or more apparatuses of the communications networks illustrated in <FIG>, <FIG>, <FIG> and <FIG> as well as for paging a remote UE, such as the systems and methods illustrated in <FIG> described and claimed herein may be embodied, such as certain nodes or functional entities in the RAN <NUM>/<NUM>/<NUM>, Core Network <NUM>/<NUM>/<NUM>, PSTN <NUM>, Internet <NUM>, Other Networks <NUM>, or Network Services <NUM>. Computing system <NUM> may comprise a computer or server and may be controlled primarily by computer readable instructions, which may be in the form of software, wherever, or by whatever means such software is stored or accessed. Such computer readable instructions may be executed within a processor <NUM>, to cause computing system <NUM> to do work. The processor <NUM> may perform signal coding, data processing, power control, input/output processing, or any other functionality that enables the computing system <NUM> to operate in a communications network. Coprocessor <NUM> is an optional processor, distinct from main processor <NUM>, that may perform additional functions or assist processor <NUM>. Processor <NUM> or coprocessor <NUM> may receive, generate, and process data related to the methods and apparatuses disclosed herein for paging a remote UE.

In operation, processor <NUM> fetches, decodes, and executes instructions, and transfers information to and from other resources via the computing system's main data-transfer path, system bus <NUM>. Such a system bus connects the components in computing system <NUM> and defines the medium for data exchange. System bus <NUM> typically includes data lines for sending data, address lines for sending addresses, and control lines for sending interrupts and for operating the system bus. An example of such a system bus <NUM> is the PCI (Peripheral Component Interconnect) bus.

Memories coupled to system bus <NUM> include random access memory (RAM) <NUM> and read only memory (ROM) <NUM>. Such memories include circuitry that allows information to be stored and retrieved. ROMs <NUM> generally include stored data that cannot easily be modified. Data stored in RAM <NUM> may be read or changed by processor <NUM> or other hardware devices. Access to RAM <NUM> or ROM <NUM> may be controlled by memory controller <NUM>. Memory controller <NUM> may provide an address translation function that translates virtual addresses into physical addresses as instructions are executed. Memory controller <NUM> may also provide a memory protection function that isolates processes within the system and isolates system processes from user processes. Thus, a program running in a first mode may access only memory mapped by its own process virtual address space; it cannot access memory within another process's virtual address space unless memory sharing between the processes has been set up.

In addition, computing system <NUM> may include peripherals controller <NUM> responsible for communicating instructions from processor <NUM> to peripherals, such as printer <NUM>, keyboard <NUM>, mouse <NUM>, and disk drive <NUM>.

Display <NUM>, which is controlled by display controller <NUM>, is used to display visual output generated by computing system <NUM>. Such visual output may include text, graphics, animated graphics, and video. The visual output may be provided in the form of a graphical user interface (GUI). Display <NUM> may be implemented with a CRT-based video display, an LCD-based flat-panel display, gas plasma-based flat-panel display, or a touch-panel. Display controller <NUM> includes electronic components required to generate a video signal that is sent to display <NUM>.

Further, computing system <NUM> may contain communication circuitry, such as for example a wireless or wired network adapter <NUM>, that may be used to connect computing system <NUM> to an external communications network or devices, such as the RAN <NUM>/<NUM>/<NUM>, Core Network <NUM>/<NUM>/<NUM>, PSTN <NUM>, Internet <NUM>, WTRUs <NUM>, or Other Networks <NUM> of <FIG>, <FIG>, <FIG>, <FIG>, or <FIG>, to enable the computing system <NUM> to communicate with other nodes or functional entities of those networks. The communication circuitry, alone or in combination with the processor <NUM>, may be used to perform the transmitting and receiving steps of certain apparatuses, nodes, or functional entities described herein.

It is understood that any or all of the apparatuses, systems, methods and processes described herein may be embodied in the form of computer executable instructions (e.g., program code) stored on a computer-readable storage medium which instructions, when executed by a processor, such as processors <NUM> or <NUM>, cause the processor to perform or implement the systems, methods and processes described herein. Specifically, any of the steps, operations, or functions described herein may be implemented in the form of such computer executable instructions, executing on the processor of an apparatus or computing system configured for wireless or wired network communications. Computer readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any non-transitory (e.g., tangible or physical) method or technology for storage of information, but such computer readable storage media do not include signals. Computer readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible or physical medium which may be used to store the desired information and which may be accessed by a computing system.

In describing preferred methods, systems, or apparatuses of the subject matter of the present disclosure - paging a remote UE - as illustrated in the Figures, specific terminology is employed for the sake of clarity. The claimed subject matter, however, is not intended to be limited to the specific terminology so selected.

The various techniques described herein may be implemented in connection with hardware, firmware, software or, where appropriate, combinations thereof. Such hardware, firmware, and software may reside in apparatuses located at various nodes of a communication network. The apparatuses may operate singly or in combination with each other to effectuate the methods described herein. As used herein, the terms "apparatus," "network apparatus," "node," "device," "network node," or the like may be used interchangeably. In addition, the use of the word "or" is generally used inclusively unless otherwise provided herein.

Claim 1:
A first device (<NUM>), the first device (<NUM>) comprising:
a processor ; and
a memory coupled with the processor, the memory storing executable instructions that when executed by the processor cause the processor to effectuate operations comprising:
enabling a relay function for relaying a paging message, wherein the enabling of the relay function is based on an indication of capacity or a number of relay wireless transmit/receive units, WTRU, proximate to the first device (<NUM>);
receiving a request to serve as a paging relay for a second device (<NUM>);
in response to the request, determining to serve as a paging relay for a second device (<NUM>);
receiving a paging message from a third device (<NUM>), the paging message comprising a paging propagation path identifier, ID; and
forwarding the paging message towards the second device (<NUM>) based on the paging propagation path ID.