Patent Description:
The document <CIT> (<NUM>-<NUM>-<NUM>) discloses a method implemented in a first wireless transmit/receive unit, WTRU, for performing a reselection to a third WTRU, in response to receiving, from a second WTRU, a first sidelink transmission comprising a first information indicating an amount of time for the first WTRU to refrain from transmitting, to the second WTRU. The document <CIT> (<NUM>-<NUM>-<NUM>) discloses that a relay WTRU notifies remote WTRUs about a congestion notification received by the relay WTRU from a network. The document <CIT> (<NUM>-<NUM>-<NUM>) discloses a relay UE receiving an accept reject message from an eNB, if the eNB cannot establish an additional DRB requested by the relay UE.

A more detailed understanding may be had from the detailed description below, given by way of example in conjunction with drawings appended hereto. Figures in such drawings, like the detailed description, are examples. As such, the Figures and the detailed description are not to be considered limiting, and other equally effective examples are possible and likely. Furthermore, like reference numerals ("ref. ") in the Figures indicate like elements, and wherein:.

The embodiments and examples depicted in <FIG>, <FIG>, <FIG>, <FIG> and <FIG> and the corresponding description are not according to the claimed invention and are present for illustration purposes only.

In the following detailed description, numerous specific details are set forth to provide a thorough understanding of embodiments and/or examples disclosed herein.

The methods, apparatuses and systems provided herein are well-suited for communications involving both wired networks, not covered by the claimed invention, and wireless networks, according to the claimed invention.

Wired networks are well-known. An overview of various types of wireless devices and infrastructure is provided with respect to <FIG>, where various elements of the network may utilize, perform, be arranged in accordance with and/or be adapted and/or configured for the methods, apparatuses and systems provided herein.

Example communications system <NUM> is provided for the purpose of illustration only and is not limiting of the disclosed embodiments. For example, the communications systems <NUM> may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail (ZT) unique-word (UW) discreet Fourier transform (DFT) spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

As shown in <FIG>, the communications system <NUM> may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) <NUM>/<NUM>, a core network (CN) <NUM>/<NUM>, a public switched telephone network (PSTN) <NUM>, the Internet <NUM>, and other networks <NUM>, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a "station" and/or a "STA", may be configured to transmit and/or receive wireless signals and may include (or be) a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronic device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a WTRU.

Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d, e.g., to facilitate access to one or more communication networks, such as the CN <NUM>/<NUM>, the Internet <NUM>, and/or the networks <NUM>. By way of example, the base stations 114a, 114b may be any of a base transceiver station (BTS), a Node-B (NB), an eNode-B (eNB), a Home Node-B (HNB), a Home eNode-B (HeNB), a gNode-B (gNB), a NR Node-B (NR NB), a site controller, an access point (AP), a wireless router, and the like.

In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each or any sector of the cell.

In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE <NUM> (i.e., Wireless Fidelity (Wi-Fi), IEEE <NUM> (i.e., 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 114b 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 campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE <NUM> to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish any of a small cell, picocell or femtocell.

For example, in addition to being connected to the RAN <NUM>/<NUM>, which may be utilizing an NR radio technology, the CN <NUM>/<NUM> may also be in communication with another RAN (not shown) employing any of a GSM, UMTS, CDMA <NUM>, WiMAX, E-UTRA, or Wi-Fi radio technology.

The CN <NUM>/<NUM> may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN <NUM>, the Internet <NUM>, and/or other networks <NUM>.

<FIG> is a system diagram of an example WTRU <NUM>. Example WTRU <NUM> is provided for the purpose of illustration only and is not limiting of the disclosed embodiments. As shown in <FIG>, the 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 <NUM>, non-removable memory <NUM>, removable memory <NUM>, a power source <NUM>, a global positioning system (GPS) chipset <NUM>, and other peripherals <NUM>, among others.

While <FIG> depicts the processor <NUM> and the transceiver <NUM> as separate components, it will be appreciated that the processor <NUM> and the transceiver <NUM> may be integrated together, e.g., in an electronic package or chip.

For example, in an embodiment, the transmit/receive element <NUM> may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element <NUM> may be configured to transmit and receive both RF and light signals.

For example, the WTRU <NUM> may employ MIMO technology.

The processor <NUM> may further be coupled to other peripherals <NUM>, which may include one or more software and/or hardware modules/units that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals <NUM> may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (e.g., for photographs or video), a universal serial bus (USB) port, 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, a virtual reality and/or augmented reality (VR/AR) device, an activity tracker, and the like.

In an embodiment, the WTRU <NUM> may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

<FIG> is a system diagram of the RAN <NUM> and the CN <NUM> according to another embodiment. 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>.

In an embodiment, the eNode-Bs 160a, 160b, 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 (UL) and/or downlink (DL), and the like.

The core network <NUM> shown in <FIG> may include a mobility management gateway (MME) <NUM>, a serving gateway (SGW) <NUM>, and a packet data network (PDN) gateway <NUM>. While each of the foregoing elements are depicted as part of the CN <NUM>, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the CN 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. 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 SGW <NUM> may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN <NUM> via the S1 interface. The SGW <NUM> may also perform other functions, such as anchoring user planes during inter-eNode-B handovers, triggering paging and/or mobile termination when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

The SGW <NUM> may also be connected to the PDN gateway <NUM>, which may provide the WTRUs 102a, 102b, 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.

In addition, the CN <NUM> may provide the WTRUs 102a, 102b, 102c with access to the other networks <NUM>, which may include other wired or wireless networks that are owned and/or operated by other service providers.

11e DLS or an <NUM>1z tunneled DLS (TDLS).

At the receiver of the receiving STA, the above described operation for the <NUM>+<NUM> configuration may be reversed, and the combined data may be sent to a Medium Access Control (MAC).

11af and <NUM>. 11af and <NUM>. 11n, and <NUM>. 11af supports <NUM>, <NUM> and <NUM> bandwidths in the TV White Space (TVWS) spectrum, and <NUM> ah supports <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> bandwidths using non-TVWS spectrum. 11ah may support Meter Type Control/Machine-Type Communications (MTC), such as MTC devices in a macro coverage area.

For example, gNBs 180a, 180b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c.

For example, OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a varying number of OFDM symbols and/or lasting varying lengths of absolute time).

In anon-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c.

Each of the gNBs 180a, 180b, 180c 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 UL and/or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b, and the like.

The CN <NUM> shown in <FIG> may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly at least one Data Network (DN) 185a, 185b.

For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different packet data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b, e.g., to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, and/or the like. The AMF 182a, 182b may provide a control plane function for switching between the RAN <NUM> and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as Wi-Fi.

The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN <NUM> via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet <NUM>, e.g., to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

In view of <FIG>, and the corresponding description of <FIG>, one or more, or all, of the functions described herein with regard to any of: WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MME <NUM>, SGW <NUM>, PGW <NUM>, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and/or any other element(s)/device(s) described herein, may be performed by one or more emulation elements/devices (not shown).

<FIG> is a block diagram illustrating an example of the communications system <NUM> including a relay WTRU <NUM>. The relay WTRU <NUM> may be configured with, and may implement, relaying functionality to support connectivity and/or traffic relaying between the network and a WTRU <NUM>. The WTRU <NUM> may be, for example, a WTRU <NUM> (<FIG>) that may be out coverage of the RAN <NUM> and cannot communicate with the core network <NUM> directly or within coverage and uses a device-to-device (D2D) link (e.g., a sidelink) for communication. For ease of exposition, the terms "remote WTRU" may be used herein to refer to a WTRU (e.g., WTRU <NUM>) that may be indirectly coupled to the network via a relay WTRU (e.g., relay WTRU <NUM>).

The relay WTRU <NUM> may be a WTRU <NUM> (<FIG>) in which the relaying functionality to support connectivity and/or traffic relaying is active (and assuming the WTRU <NUM> (<FIG>) is configured with such functionality). Although not shown, the relay WTRU <NUM> may provide connectivity and/or traffic relaying between the network and more than one remote WTRU.

For simplicity of exposition, the relay WTRU <NUM> and the remote WTRU <NUM> are assumed to be configured in accordance with one or more protocols of proximity services (ProSe). ProSe are services that can be provided by the communications system based on a plurality of WTRUs being in proximity to each other.

<FIG> illustrates an example relaying establishment procedure. For simplicity of exposition, the example relaying establishment procedure is described using the communications system <NUM> of <FIG> (and in turn <FIG>). The example relaying establishment procedure may be carried out in other communications systems, as well.

According to the procedure, a relay WTRU <NUM> may register with an AMF 182a. The relay WTRU <NUM>, for example, may send a registration request message to the AMF 182a (<NUM>) to request registration, and the AMF 182a may accept the registration and send a registration accept to the relay WTRU <NUM> (<NUM>) to indicate acceptance of the requested registration.

After registration, a remote WTRU <NUM> may perform discovery and select the relay WTRU <NUM> (<NUM>). The remote WTRU <NUM> may decide to perform discovery and/or select the relay WTRU <NUM>, for example, if it is out of coverage of a RAN <NUM> and cannot communicate with the core network <NUM> directly and/or if it within coverage but decides to use a D2D link (e.g., PC5 link/sidelink) for communication. The remote WTRU <NUM> may establish a PC5 session with the relay WTRU <NUM> (<NUM>). The relay WTRU <NUM> may establish a PDU session (or PDN connection in EPC) for the remote WTRU <NUM> (<NUM>,<NUM>). After IP address/prefix allocation (<NUM>), traffic between the remote WTRU <NUM> and the network may be relayed by the relay WTRU <NUM>.

The remote WTRU <NUM> may access the network via the relay WTRU <NUM>. The terms "relay WTRU", "WTRU-to/from-network relay", "ProSe L2 WTRU-to/from-network relay", "ProSe L2 relay", and "WTRU-based relay" may be used interchangeably herein.

<FIG> illustrates example protocol stacks and interconnecting reference points of a remote WTRU <NUM>, a relay WTRU <NUM> (shown as "ProSe L2 Relay"), a RAN <NUM> (e.g., <NUM>-AN) and a AMF of the remote WTRU <NUM> ("remote-WTRU AMF 182a-<NUM> ").

The remote WTRU <NUM> may be visible to the network with the relay WTRU <NUM> there between. The RAN <NUM> (e.g., <NUM>-AN) may terminate radio resource control (RRC) signalling and NG-AP signalling. The behaviour of the remote WTRU <NUM> with respect to functionality provided by, and/or protocols of, the remote-WTRU AMF 182a-<NUM> may be the same to that of a WTRU directly coupled to the RAN <NUM> (e.g., <NUM>-AN). From the perspective at the RAN <NUM> (e.g., <NUM>-AN), the remote WTRU <NUM> may access it via the relay WTRU <NUM> and the RRC layer behaviour may be the same to that of a WTRU directly coupled to the RAN <NUM> (e.g., <NUM>-AN). Although not shown in <FIG>, the relay WTRU <NUM> may select, be assigned and/or couple to the same AMF 182a-<NUM> as the remote WTRU <NUM> or, alternatively, select, be assigned and/or couple to an AMF other than the AMF 182a-<NUM>. For ease of exposition, the terms "relay AMF" may be used herein to refer to an AMF that may be selected by, assigned to and/or coupled with a relay WTRU (e.g., relay WTRU <NUM>).

NAS level congestion control may be initiated at any of a mobility management (MM) level and a session management (SM) level. The NAS level congestion control involves, among other things, (i) the network providing to a WTRU a value for a (e.g., configured) back-off timer and (ii) the WTRU backing off from or otherwise not initiating any NAS signalling until the back-off timer ("NAS back-off timer") expires or until the WTRU receives a mobile terminated (MT) request from the network.

The value of the NAS back-off timer provided at the MM level is generally sent by an associated AMF in a NAS reject message. As an example, when the AMF is congested and receives a NAS request (e.g. Registration or Service Request) message from the WTRU, the AMF may reject the request and may send a NAS reject message that includes a value for the NAS back off timer. The WTRU may receive the NAS back off timer value, initialize the NAS back off timer with the received value, start the NAS back-off timer, and refrain from initiating any NAS signalling (e.g., any NAS request), except possibly for initiating a deregistration procedure, until expiration of the NAS back-off timer or until the WTRU receives a MT request from the network and the like.

During registration (update), an AMF may disallow and/or deactivate mobile initiated connection only (MICO) mode for a WTRU if communication pattern parameters indicate uncertainty of downlink (DL) communications, or that DL communication is happening soon, e.g. within a preconfigured time window. The AMF may allow and/or activate the MICO mode in the other power saving cases.

For a WTRU in MICO mode, if the communication pattern parameters indicate the absence of DL communication, the AMF may allocate a large periodic registration timer value so that, the WTRU can enter deep sleep between periodic registration updates to save power. If the communication pattern parameters indicate scheduled DL communication, then the AMF should allocate a periodic registration timer value such that the WTRU may perform periodic registration update to renegotiate MICO mode before or at the scheduled DL communication time based on the expected WTRU behavior from the application server.

The AMF may provide a "do not reset the timer for Periodic Registration" indication to the WTRU together with the periodic registration timer value. If the "do not reset the timer for Periodic Registration" indication is provided by the AMF, then the WTRU may keep its periodic registration timer running while in CM-CONNECTED state. The WTRU may re-negotiate MICO mode and its parameters the periodic registration timer (e.g., by performing a periodic registration update) at or after expiration of the periodic registration timer. The periodic registration timer is only restarted on expiry. If the periodic registration timer value is renegotiated during a Registration procedure the periodic registration timer is stopped and restarted using the renegotiated value even when the "do not reset the timer for Periodic Registration" indication was provided by the AMF.

A core network may maintain a context for a remote WTRU connected via an relay WTRU in the same way as it would if the WTRU is connected directly to the network and has N1 interface with the AMF. The remote-WTRU AMF while interacting with the remote WTRU need not change its procedures and behavior since the remote WTRU may transmit messages via the relay WTRU.

A common scenario may be that a remote WTRU and the relay WTRU are attached/registered to different AMFs. Even if they are connected to the same AMF, the AMF may keep separate contexts for remote WTRU and the relay WTRU. The behavior of AMF for one the WTRUs may not consider that both signaling and traffic from one WTRU is being relayed by another WTRU. The AMF may apply the same behavior and procedure, e.g., NAS signaling to each of the WTRUs.

Application of similar procedures and NAS signaling for both the relay WTRU and the remote WTRU is a key benefit of L2 relaying. The network may have visibility and control over the remote WTRU because of transparent relaying of NAS signaling. The AMF behavior for a relay WTRU in certain scenarios may not take into consideration that there are remote WTRUs connected to relay WTRUs via PC5 (since they may be connected to different AMFs).

NAS level congestion and subsequently application of back off timers is one such scenario. It may be possible that relay-WTRU AMF is congested causing the AMF to send NAS back off timer (e.g. mobility management) to relay WTRU. Upon receiving the back off timer, the relay WTRU would not be able to initiate mobility management signaling until the expiry of the timer.

The remote WTRU may not be cognizant of such congestion situation at the relay WTRU. As part of the normal operation, the remote WTRU may send request to the relay WTRU (e.g. PC5 request). The relay WTRU may not be able to transition to connected mode (because of the mobility management back off timer) and may not be able to connect the remote WTRU to the network.

Under the scenario disclosed herein, the relay WTRU AMF congestion may cause service interruptions and connectivity issues for the remote WTRU. Various embodiments disclosures herein address the L2 relay WTRU behavior with respect to experiencing network congestion (e.g., receiving a value for a back off timer from its AMF and having a pending request to relay data from the remote WTRU.

There are cases in which the RAN may be experiencing an overload or congestion scenario. As an example, it could be the case where the CN, e.g., the AMF, is congested. In that case, the CN may inform RAN to start a overload control mechanism by sending a message with the overload indication. When the RAN (i.e. a gNB in the case of <NUM> NW) receives this indication, it may apply it toward the WTRUs that want to access the network. As an example, when a WTRU tries to access the network by means of requesting to establish an RRC Connection, the RAN may reject it and also provide an extended wait time (EWT) to the WTRU. The reception of the EWT may trigger the RRC layer of the WTRU to indicate it to the NAS layer and the NAS layer may apply the back-off mechanism (e.g., by means of starting a MM-level back-off timer with the same value as the received EWT. The Relay WTRU that receives the EWT form RAN and not the remote WTRU, may need to contact the NW. Various embodiments disclosures herein address the behavior of the relay WTRU in connection with receiving the EWT from RAN, how the relay WTRU may communicate with the remote WTRU and what action(s) should the remote WTRU take.

There are scenarios in which the WTRU may not reset its periodic timer when it transitions to connected mode before the expiry of the timer. The network may keep track of intervals when the WTRU exits sleep mode, e.g., idle mode/eDRX MICO or PSM. Such tracking may enable the network to schedule delivery of MT data at these time intervals. The network may inform (e.g., also inform) the application server that the WTRU may be available at these times for the application server to be able schedule data if it has any at those times.

The remote WTRU (e.g., an IoT type remote WTRU) in some scenario might want to use the 'Scheduled Delivery of MT Data' feature. Enabling this feature in L2 relaying may increase complexity since idle mode behavior of the relay WTRU may need to be taken into consideration to determine the MT data delivery time schedules. The idle mode intervals or periodic timer of the relay WTRU may not be in synch with the times when the remote WTRU performs period registration.

Additional behavior may be needed at both the remote WTRU and the relay WTRU to enable (e.g., seamlessly enable) the 'Scheduled Delivery of MT Data' feature at the remote WTRU. Various embodiments disclosures herein address how to enable receiving schedule MT data when the remote WTRU has a long period of inactivity (e.g. in eDRX, MICO, PSM, etc.).

Mobility restrictions may restrict mobility handling or service access of a WTRU. Mobility restrictions may include RAT restriction, Forbidden Area, Service Area Restrictions, Core Network type restriction and Closed Access Group information. Mobility restrictions are decided by the Core Network.

With mobility restrictions, the WTRU may be restricted from initiating any communication with the network for this PLMN (in Forbidden Area), or initiating a service request or SM signalling (in Non-Allowed Area), etc..

Since the network may provide different mobility restrictions to the remote WTRU and L2 Relay WTRU, various embodiments disclosures herein address L2 relay WTRU behavior when it moves to an area with mobility restrictions, e.g. Forbidden Area or Non-allowed area, and it receives a pending request to relay data/signaling from a remote WTRU.

Procedures, methods, architectures, apparatuses, systems, devices, and computer program products directed to non-access stratum procedures in connection with layer <NUM> relaying are disclosed herein. Among such apparatuses is a relay WTRU that is experiencing, expected to experience and/or informed of upstream congestion (e.g. NAS level congestion) may inform a remote WTRU of such congestion in various ways and may take various actions and/or cause various actions to be taken to bar or otherwise limit UL and/or DL relaying operation and/or override congestion control mechanisms to allow any of UL and DL relaying operation. For example, the relay WTRU may take various actions to inhibit the remote WTRU, and/or to cause the remote WTRU to refrain, from communicating with the relay WTRU for a time period. That time period may be for all, some or more than the time during which the relay WTRU is experiencing and/or expected to experience congestion. The time period may be based on one or more signaled values, set initially to one value (e.g., a fixed value, infinity, etc.) and then adjusted up or down with another value, etc..

The relay WTRU, for example, may use a procedure for disconnecting an ongoing PC5 link between peer WTRUs to inform the remote WTRU of the congestion and/or to inhibit the remote WTRU, and/or cause the remote WTRU to refrain, from communicating with the relay WTRU indefinitely or for some other time period. After the relay WTRU receives a NAS message (e.g. NAS reject message) with a value for a NAS back off timer, the relay WTRU may proceed by releasing its ongoing unicast PC5 connections with the remote WTRU (and/or some or all of any other ongoing unicast PC5 connections). The relay WTRU may, as part of the link release procedure, inform the remote WTRUs whose connections are being released of the cause for the release, for example, using a specific cause code that indicates the cause for link release is that the relay WTRU experiencing, expected to experience and/or has been informed of upstream congestion (e.g. NAS level congestion). The relay WTRU may, as part of the link release procedure, inform the remote WTRUs that it may not be able to accept new PC5 connections for a time period. The remote WTRUs may use this information to refrain from initiating a PC5 connection (or otherwise communicating via the PC5 with) the relay WTRU for the duration of such period. As an example, the remote WTRUs may be configured with a PC5 back-off timer and configured to refrain from initiating a PC5 connection (or otherwise communicating via the PC5 with) the relay WTRU until expiration of the PC back-off timer. The relay WTRU may provide to the remote WTRUs values for their respective PC5 back off timers. After receipt of such values, the remote WTRUs may refrain (and/or be inhibited) from communicating with the relay WTRU until expiration of their respective timers. The PC5 back off timer values may be based on the NAS back off timer value. For example, the PC5 back off timer values provided during the link release procedure may be set as an offset of the NAS back off timer values received by the relay WTRU. The relay WTRU may otherwise derive the PC5 back off timer values from the received NAS back off time value.

The relay WTRU may decide to initiate the release procedure with a remote WTRU if (e.g., only if) the remote WTRU has data to be sent and no DL data is expected to be received and/or the remote WTRU is not in an idle state. For example, the relay WTRU may refrain from using the link release procedure for remote WTRUs (e.g., remote WTRUs in MICO mode) that only send data at specific intervals, and such interval does not occur during the time corresponding to the NAS back-off timer and/or the time during which the relay WTRU is experiencing, expected to experience and/or informed of upstream congestion.

The relay WTRU may select the ongoing PC5 connections to be released based on various criteria, e.g. level of activity (sending/receiving data), QoS, service type, etc.).

<FIG> is a message flow diagram illustrating an example link release procedure in accordance with various embodiments. For simplicity of exposition, the example link release procedure is described using the communications system <NUM> of <FIG> (and in turn <FIG>). The example link release procedure may be carried out in other communications systems, as well.

The relay WTRU may send, to the relay-WTRU AMF, a NAS request (e.g., a registration request or service request) message to transition from idle mode to connected mode (<NUM>). The relay-WTRU AMF may receive the NAS request at a time in which the it is congested and may decide to reject the NAS request.

Based such decision, the relay-WTRU AMF may send a NAS reject message to the relay WTRU. The NAS reject message may include a value for a NAS back off timer (<NUM>). After receipt of the NAS reject message, the relay WTRU may start its NAS back-off timer using (or based on) the received value and may initiates the link release procedure with the remote WTRU. The relay WTRU may send a link release request PC5 message (<NUM>) as part of the link release procedure. The link release request PC5 message may include (i) a specific cause code for indicating the cause for link release is that the relay WTRU experiencing, expected to experience and/or has been informed of upstream congestion, and (ii) a value for a PC5 back off timer. The remote WTRU may receive the link release request PC5 message, and a consequence, the remote WTRU becomes aware of the congestion situation at the relay WTRU. The cause code, for example, indicates the AMF/NAS congestion experienced by the relay WTRU, and the value for PC5 back off timer informs the remote WTRU of a duration of time for which the relay WTRU may not be able to accept new PC5 requests.

The remote WTRU may respond to the link release request PC5 message by sending to the relay WTRU a link release accept message (<NUM>). The remote WTRU may perform one or more of the following actions after receiving link release request PC5 message:.

In various embodiments, when a relay WTRU receives the NAS back off timer from its corresponding relay-WTRU AMF, the relay WTRU may inform the remote WTRU of the congestion and the remote WTRU may refrain from initiating a PC5 connection (or otherwise communicating via the PC5 with) the relay WTRU based on such information.

The relay WTRU, for example, may provide an indication of (or otherwise indicate) the congestion in a next keep alive (or other type) PC5 message and/or one or more subsequent keep alive (or other type) PC5 messages. An explicit congestion indication may be included with a signaled value of the PC5 back off timer (which value may possibly be based on (e.g., derived from) a signaled value NAS back off timer). The relay WTRU may implicitly indicate the relay WTRU congestion to the remote WTRU by excluding a value for the PC5 back off timer in the keep alive message(s). The relay WTRU may indicate the that the relay WTRU is no longer experiencing congestion by excluding the indication and/or a value for the PC5 back off timer in the keep alive message(s) after having sent the indication and/or value in one or more previous keep alive (or other type) PC5 messages.

In various embodiments, the relay WTRU may send the back off indication and/or value for the PC5 back off timer when it receives (e.g., responsive to receiving) a mobile originated (MO) request from the remote WTRU to relay data or signaling message.

In various embodiments, the relay WTRU may initiate a link modification procedure (e.g., with an indication) to pause the link or temporarily move to the dormant state. The link modification PC5 message may include a value for a timer for the duration of the dormant period. In an embodiment, the relay WTRU may initiate another link modification procedure when the congestion has abated (e.g., prior to expiration of a PC back-off timer) to indicate to the remote WTRU that it may resume the service and come out of the dormant state.

In various embodiments, the relay WTRU may cause the remote WTRU to cancel the PC5 back off timer. The relay WTRU, for example, may cause the cancelation of the PC5 back off timer based on (e.g., responsive to) receiving a paging message or a mobile terminated (MT) request from the relay-WTRU AMF. In various embodiments, the relay WTRU may initiate the cancelation procedure by sending a "cancel back off' indication to the remote WTRU, e.g., in the keep alive message and/or another PC5-S message, such as a link modification request. The remote WTRU may receive the "cancel back off' indication, and may reset the PC5 back off timer (e.g., set the value to zero) and, in turn, allow the remote WTRU to resume service and/or come out of dormant state.

When the remote WTRU receives the back off timer in the keep alive message, the remote WTRU may refrain from sending to the relay WTRU any messages (NAS signaling and/or data) to be relayed. The remote WTRU may transmit PC5 signaling messages to the relay WTRU if the back off timer is running or not.

While the PC5 back off timer is running, the remote WTRU may perform one or more of the following actions (e.g., in addition to any of the remote WTRU behaviors disclosed above in connection with the link release procedure):.

In various embodiments, the congestion associated with relay-WTRU AMF may allow the relay WTRU to transmit signaling messages and data for the remote WTRU (e.g., when served by an AMF other than the relay-WTRU AMF). When the AMF sends the back off timer to the relay WTRU, additional (new) information associated to the back off timer may be sent to the relay WTRU in the NAS reject message (e.g. service reject or registration reject). The corresponding information may indicate to the relay WTRU whether the NAS back off timer is applicable to remote WTRU connections (e.g., some or all remote WTRU connections. Examples of the additional information associated with the NAS back off timer may include any of:.

If the additional information associated with the NAS back off timer suggests that the received value for the NAS back off timer is (e.g., is only) applicable to relay-WTRU mobile originated (MO) requests, then the relay WTRU need not inform the remote WTRU about relay-WTRU AMF congestion. When sending a service request or registration message, the relay WTRU may inform the relay WTRU AMF by including a new indication ('"relaying indication") in the NAS message specifying that the current registration request or service request has been initiated based on MO request from the remote WTRU. The relaying indication may be included as part of new establishment cause at the RRC or NAS level.

<FIG> is a message flow diagram illustrating an example congestion control override procedure in accordance with various embodiments. For simplicity of exposition, the congestion control override procedure is described using the communications system <NUM> of <FIG> (and in turn <FIG>). The example congestion control override procedure may be carried out in other communications systems, as well.

The relay WTRU may send to the relay-WTRU AMF a NAS request (e.g., a registration request or a service request) to transition out of idle state (<NUM>). The relay-WTRU AMF may receive and reject the NAS request due to relay-WTRU network congestion. The relay-WTRU AMF may send a NAS reject message to the relay WTRU (<NUM>). The NAS reject message may include a value for the NAS back off timer and information indicating the applicability of the back off timer (e.g. information indicating that NAS back off is only applicable to relay WTRU requests). The relay WTRU may receive the NAS reject message, initialize the NAS back off timer using the received value, and start the NAS back off timer.

The relay WTRU may receive a MO request (e.g. a service request) from the remote WTRU (<NUM>). This may occur, for example, if the remote WTRU tries to transition to connected mode.

Based on a characteristic of the received back off timer (e.g., the additional information associated with the NAS back off timer), the relay WTRU may decides to relay the MO request from the remote WTRU (<NUM>). For example, if the remote WTRU and relay WTRU are served by different AMFs, then the relay WTRU may determine to relay the remote WTRU request if the back-off timer additional information indicates that remote WTRU requests are allowed (if served by a different AMF). The relay WTRU may determine the remote WTRU AMF identity based on a remote WTRU temporary identity (e.g., a GUTI).

The relay WTRU may send the service request message to the relay-WTRU AMF (<NUM>). The service request message may include a new indication informing the relay-WTRU AMF that the request to establish NAS signaling is due (e.g., responsive) to an MO request from the remote WTRU.

Based on the new indication, the relay WTRU AMF may accept the request and send a service accept message (<NUM>). The MO request (e.g. service request) may be relayed to the remote-WTRU AMF by the relay WTRU (<NUM>).

After receiving a NAS reject message, the relay WTRU may make itself unavailable for direct discovery for the duration of the back off timer (e.g. stop transmission of broadcast discovery messages or stop monitoring/replying to direct discovery request messages). The relay WTRU may resume normal discovery operations (e.g. resume transmission of broadcast discovery messages or resume monitoring/replying to direct discovery request messages) when the NAS congestion condition is abated (e.g. when back off timer expires and a following NAS request is accepted).

The relay WTRU may also reject new direct connection requests received while the back off timer is still running. The reject message may include a specific cause code indicating that the link establishment request is rejected due to relay-WTRU being under NAS level congestion conditions. The reject message may include (e.g., also include) a value for the back off timer indicating to the remote WTRU that the relay WTRU may not be able to accept new PC5 connections for the duration of the timer. The relay WTRU may derive this PC5 back off timer value from the received NAS back off value, e.g., as an offset or multiplier of the NAS back off timer value or back off timer remaining running time. The remote WTRU may re-attempt connecting with the relay WTRU upon that timer expiry.

Alternatively, the relay WTRU may discard new direct connection requests received while the back off timer is still running. In that scenario, the remote WTRU may retransmit new direct connection request(s) based on conventional retransmission timer.

In various embodiments, the discovery mechanism may still be run. and an unavailable indication and/or an expected available time (or back-off timer) may added to the advertisements to let the listening WTRUs know about the relay-WTRU current congestion situation and duration. Remote WTRUs may try to connect with the relay WTRU once available expected time is reached.

A relay WTRU experiencing congestion and which has the capability of sending data to the network, e.g. as herein, or for specific service types, may decide to not advertise its congestion level or to advertise it with an added indication about which traffic is allowed to be relayed.

In various embodiments, the relay UE, upon attempting to establish an RRC connection with the RAN and receiving value for an extended wait time (EWT) in a reject or release message, may inform the remote WTRU of the congestion/overload situation in RAN and also pass the value of the EWT to the remote WTRU. This may be carried out by e.g. sending a PC5 message to the remote WTRU, for instance. The choice of the PC5 message may depend on the condition of the PC5 link between the two UEs. As an example, where a PC5 link already exists and the link is supervised by the two UEs, keep alive messages can be used. Alternatively, where no link exists and/or is running at this point, the relay WTRU may broadcast an indication in a discovery message to inform interested remote-WTRU that that the relay WTRU is experiencing RAN level congestion. Alternatively, the relay WTRU may inform the remote WTRU about the status of the RAN while accepting a unicast communication establishment from the remote WTRU. The remote WTRU may apply the EWT as a NAS back-off timer. In addition, where the remote WTRU is in either PSM or MICO mode, it may go back to PSM/MICO immediately or without further delay (e.g., to avoid waiting for the network to allocate an active time).

The "do not reset the timer for Periodic Registration" timer feature may be enabled by the remote WTRU AMF if the remote WTRU requests enablement of power saving e.g. MICO in the registration message. The remote-WTRU AMF may send this indication to the remote WTRU in a registration accept message. Coordination between the remote WTRU and the relay WTRU may be needed so that idle mode operation of the relay WTRU does not disrupt a scheduled wake up time of the remote WTRU.

The remote WTRU, for example, may inform the relay WTRU about the activation of "do not reset the timer for Periodic Registration" feature when the remote WTRU receives such indication in the registration accept message from the AMF. The remote WTRU may send (e.g., also send) its periodic update timer value to the relay WTRU. The remote WTRU may send this information to the relay WTRU via PC5 Signaling message, for example, direct communication request or link modification request. The information about activation of "do not reset the timer for Periodic Registration" feature may be sent by the remote WTRU, e.g., when the remote WTRU transitions to idle mode.

The remote WTRU may inform the relay WTRU when it moves from connected mode to idle mode (e.g., a monitor request). Part of the messaging may be to inform this state change to the relay WTRU. The remote WTRU may add new information elements in the message to indicate that remote WTRU would not be resetting the periodic timer in the event of MO request, and may send the corresponding periodic timer to the relay WTRU.

After receiving the information about the "do not reset the timer for Periodic Registration" feature activated at the remote WTRU, the relay WTRU may adapt certain behavior to facilitate the scheduled wake up times for the remote WTRU. The relay WTRU may take any of the following actions:.

<FIG> is a message flow diagram illustrating a procedure for enabling scheduled mobile terminated (MT) data delivery for a remote WTRU. For simplicity of exposition, the procedure for enabling scheduled MT data delivery for a remote WTRU is described using the communications system <NUM> of <FIG> (and in turn <FIG>). The example procedure for enabling scheduled MT data delivery for a remote WTRU may be carried out in other communications systems, as well.

A remote WTRU may request MICO from the network (e.g., the remote-WTRU AMF) (<NUM>). The network may send a registration accept message to the remote WTRU (<NUM>). The registration accept message may include the "do not reset the timer for Periodic Registration". The remote WTRU may receive the registration accept message (<NUM>).

At state change to idle mode, the remote WTRU may inform the relay WTRU that the schedule MT feature is enabled (<NUM>). The remote WTRU, for example, may send a PC5 signaling message to the relay WTRU. The PC5 signaling message may include an indication that the schedule MT feature is enabled and/or a value of the periodic time.

The request may be acknowledged by the relay WTRU (<NUM>). The relay WTRU, for example, may sending a PC5 signaling response message.

Received parameters from the remote WTRU may be used by the relay WTRU to determine its idle mode behavior (e.g. enable/disable power saving) and corresponding parameters (e.g. requested active time, periodic timer etc.) (<NUM>).

The relay WTRU may send a registration message with a new indication of the remote WTRU enabling scheduled MT data delivery feature and possibly remote WTRU periodic timer in addition to the new idle mode parameters (<NUM>).

In various embodiments, when the L2 relay WTRU is in a mobility restrictions area, e.g., a forbidden area or non-allowed area, and the L2 relay WTRU receives a message from remote WTRU which triggers the L2 relay WTRU to send message to the network (e.g. service request), the L2 relay WTRU may include an indication that the message is exempted from restriction, e.g. due to triggered for remote WTRU. The AMF may accept the message (e.g. service request).

In various embodiments, the network may indicate whether the mobility restrictions area for the L2 relay WTRU may apply to message triggered by remote WTRU. For example, the network may provide a set of non-allowed areas for the L2 relay WTRU itself (e.g., areas in which the L2 relay WTRU may be restricting from sending a service request to network for the L2 relay-WTRU data or signaling) and a set of non-allowed area for the remote WTRU (e.g., areas in which the L2 relay WTRU may be restricted from sending a service request to network even it's triggered for data or signaling of the remote-WTRU).

Examples of the L2 relay-WTRU behaviors may include one or more of the following:.

<FIG> is an example of a method <NUM> implemented in a first WTRU. The method may comprise the following steps. At step <NUM>, the first WTRU may receive, from a second WTRU, via a first sidelink, a first information indicating an amount of time (e.g., a time period) for the first WTRU to refrain from transmitting to the second WTRU. As an example, the first WTRU may be refrain from transmitting to the second WTRU a second information, for termination to a network element, that may have to be relayed by the second WTRU. The first sidelink may include a first sidelink transmission comprising the first information. As a discovery process to discover another WTRU, at step <NUM>, the first WTRU may determine to reselect to a third WTRU responsive to receiving the first information and based on a second sidelink transmission from the third WTRU. Reselecting to the third WTRU may comprise autonomous reselecting to the third WTRU. At step <NUM>, the first WTRU may reselect to the third WTRU. The reselection may be processed on the second sidelink responsive to receiving the first information. At step <NUM>, the first WTRU may establish a connection with the third WTRU. At step <NUM>, the first WTRU may transmit to the third WTRU, a third sidelink transmission comprising a third information indicating congestion as a cause for the reselection.

The third sidelink transmission may addressed to, destined for, or terminated to the third WTRU. More particularly, the third sidelink transmission may comprise a first message addressed to, destined for, or terminated to a network element. The first message may comprise the third information indicating congestion as a cause for the reselection. The amount of time for the first WTRU to refrain from transmitting to the second WTRU may comprise a value for a back off timer. The network element may be associated with the first WTRU and/or with the third WTRU.

The method of <FIG> may further comprise a step of transmitting, to a network element via the third WTRU, a fourth sidelink transmission comprising a fourth information indicating congestion as a cause for the reselection, wherein the fourth sidelink transmission is destined for/terminated to the network element. The network element may comprise an access and mobility management function, AMF.

The third information may be included in a message to the third WTRU during discovery so that the third WTRU may use the third information to determine whether to allow the first WTRU to connect thereto.

Prior to performing discovery or prior to establishing the connection with the third WTRU, the method of <FIG> may further comprise a step of determining whether an identifier of the third WTRU is listed on a first list of identifiers of WTRUs that are available for relaying and/or determining whether an identifier of the third WTRU is not listed on a second list of identifiers of WTRUs that are unavailable for relaying.

The fourth sidelink transmission may comprise a second message comprising the third information, and wherein the second message is in a protocol according to a non-access stratum, NAS, protocol.

The first sidelink transmission may comprise a third message comprising the first information, and wherein the third message is in a protocol according to any of a NAS protocol and a radio resource control, RRC, protocol and a PC5 protocol. The third message may comprise any of a link release message and a PC5 message.

<FIG> is another example of a method <NUM> implemented in a first WTRU. The method may comprise the following steps. At step <NUM>, the first WTRU may receive, from a second WTRU, a first sidelink transmission comprising a first information indicating an amount of time for the first WTRU to refrain from transmitting to the second WTRU. At step <NUM>, the first WTRU may determine to reselect to a third WTRU responsive to receiving the first information and based on a second sidelink transmission from the third WTRU. At step <NUM>, the first WTRU may reselect to the third WTRU. Reselecting to the third WTRU may comprise autonomous reselecting to the third WTRU. At step <NUM>, the first WTRU may establish a connection with the third WTRU. At step <NUM>, the first WTRU may transmit to a network element via the third WTRU, a third sidelink transmission comprising a second information indicating congestion as a cause for the reselection, wherein the third sidelink transmission is addressed to, destined for or terminated to the network element.

<FIG> is another example of a method <NUM> implemented in a first WTRU. The method may comprise the following steps. At step <NUM>, the first WTRU may receive from a second WTRU, a first sidelink transmission comprising a first information indicating an amount of time for the first WTRU to refrain from transmitting to the second WTRU. At step <NUM>, the first WTRU may reselect to a network element responsive to receiving the first information. The reselection to the network element may comprise autonomous reselection to the network element At step <NUM>, the first WTRU may establish or maintain a connection with the network element. At step <NUM>, the first WTRU may transmit, to the network element, a second information indicating congestion as a cause for establishing the connection.

The network element may comprise an access and mobility management function, AMF. The AMF may be associated with the first WTRU.

<FIG> is another example of a method <NUM> implemented in a first WTRU. The method may comprise the following steps. At step <NUM>, the first WTRU may receive, from a second WTRU, a first sidelink transmission comprising, a first information indicating a schedule for mobile terminated (MT) data for the second WTRU. At step <NUM>, the first WTRU may determining idle mode parameters of the first WTRU based on the first information. At step <NUM>, the first WTRU may transmit to a network element associated with the first WTRU, a second information indicating idle mode parameters of the first WTRU.

A first message may comprise the first information, and the first information may indicate one or more parameters corresponding to scheduling MT data. The method of <FIG> may further comprise a step of transmitting, to a network element associated with the first WTRU, a third information indicating the second WTRU is enabled to receive MT data.

<FIG> is another example of a method <NUM> implemented in a first WTRU. The method may comprise the following steps. At step <NUM>, the first WTRU may receive, from a network element, a first information indicating an amount of time for the first WTRU to refrain from transmitting to the network element. At step <NUM>, the first WTRU may receive from a second WTRU, a first sidelink transmission comprising a second information indicating a service request for mobile originated (MO) data. At step <NUM>, the first WTRU may relay the second information to a first network element performing an AMF. The first network element may be associated with the first WTRU. At step <NUM>, the first WTRU may receive from the first network element, a third information indicating acceptance of the service request. At step <NUM>, and on condition that the type of MO request is a first type, the first WTRU may relay the second information to a second network element performing an AMF. The second network element may be associated with the second WTRU.

According to various embodiments, a method implemented in a WTRU experiencing, expected to experience and/or informed of upstream congestion, may comprise the following steps: informing a remote WTRU of such congestion; and causing various actions to be taken at the remote WTRU to bar or otherwise limit UL and/or DL relaying operation.

According to various embodiments, a method implemented in a WTRU experiencing, expected to experience and/or informed of upstream congestion, may comprise the following steps: informing a remote WTRU of such congestion; and override congestion control mechanisms applied to the relay WTRU to allow UL and/or DL relaying operation.

The various actions may comprise causing the remote WTRU to refrain from communicating with the relay WTRU for a time period. The period may be based on a time during which the relay WTRU is experiencing and/or expected to experience congestion. The time period may be based on one or more signaled values. The time period may be set initially to one value and then adjusted up or down with another value, etc..

Although features and elements are provided above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations may be made without departing from its spirit and scope, as will be apparent to those skilled in the art. No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly provided as such. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods or systems.

The foregoing embodiments are discussed, for simplicity, with regard to the terminology and structure of infrared capable devices, i.e., infrared emitters and receivers. However, the embodiments discussed are not limited to these systems but may be applied to other systems that use other forms of electromagnetic waves or non-electromagnetic waves such as acoustic waves.

It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used herein, the term "video" or the term "imagery" may mean any of a snapshot, single image and/or multiple images displayed over a time basis. As another example, when referred to herein, the terms "user equipment" and its abbreviation "UE", the term "remote" and/or the terms "head mounted display" or its abbreviation "HMD" may mean or include (i) a wireless transmit and/or receive unit (WTRU); (ii) any of a number of embodiments of a WTRU; (iii) a wireless-capable and/or wired-capable (e.g., tetherable) device configured with, inter alia, some or all structures and functionality of a WTRU; (iii) a wireless-capable and/or wired-capable device configured with less than all structures and functionality of a WTRU; or (iv) the like. Details of an example WTRU, which may be representative of any WTRU recited herein, are provided herein with respect to <FIG>. As another example, various disclosed embodiments herein supra and infra are described as utilizing a head mounted display. Those skilled in the art will recognize that a device other than the head mounted display may be utilized and some or all of the disclosure and various disclosed embodiments can be modified accordingly without undue experimentation. Examples of such other device may include a drone or other device configured to stream information for providing the adapted reality experience.

In addition, the methods provided herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Variations of the method, apparatus and system provided above are possible without departing from the scope of the invention. In view of the wide variety of embodiments that can be applied, it should be understood that the illustrated embodiments are examples only, and should not be taken as limiting the scope of the following claims. For instance, the embodiments provided herein include handheld devices, which may include or be utilized with any appropriate voltage source, such as a battery and the like, providing any appropriate voltage.

Moreover, in the embodiments provided above, processing platforms, computing systems, controllers, and other devices containing processors are noted. These devices may contain at least one Central Processing Unit ("CPU") and memory. In accordance with the practices of persons skilled in the art of computer programming, reference to acts and symbolic representations of operations or instructions may be performed by the various CPUs and memories. Such acts and operations or instructions may be referred to as being "executed," "computer executed" or "CPU executed.

One of ordinary skill in the art will appreciate that the acts and symbolically represented operations or instructions include the manipulation of electrical signals by the CPU. An electrical system represents data bits that can cause a resulting transformation or reduction of the electrical signals and the maintenance of data bits at memory locations in a memory system to thereby reconfigure or otherwise alter the CPU's operation, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties corresponding to or representative of the data bits. It should be understood that the embodiments are not limited to the above-mentioned platforms or CPUs and that other platforms and CPUs may support the provided methods.

The data bits may also be maintained on a computer readable medium including magnetic disks, optical disks, and any other volatile (e.g., Random Access Memory (RAM)) or non-volatile (e.g., Read-Only Memory (ROM)) mass storage system readable by the CPU. It should be understood that the embodiments are not limited to the above-mentioned memories and that other platforms and memories may support the provided methods.

There is little distinction left between hardware and software implementations of aspects of systems. The use of hardware or software is generally (but not always, in that in certain contexts the choice between hardware and software may become significant) a design choice representing cost versus efficiency tradeoffs. There may be various vehicles by which processes and/or systems and/or other technologies described herein may be effected (e.g., hardware, software, and/or firmware), and the preferred vehicle may vary with the context in which the processes and/or systems and/or other technologies are deployed. For example, if an implementer determines that speed and accuracy are paramount, the implementer may opt for a mainly hardware and/or firmware vehicle. If flexibility is paramount, the implementer may opt for a mainly software implementation. Alternatively, the implementer may opt for some combination of hardware, software, and/or firmware.

In an embodiment, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), and/or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, may be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and or firmware would be well within the skill of one of skill in the art in light of this disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subj ect matter described herein may be distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a CD, a DVD, a digital tape, a computer memory, etc., and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communications link, a wireless communication link, etc.).

Those skilled in the art will recognize that it is common within the art to describe devices and/or processes in the fashion set forth herein, and thereafter use engineering practices to integrate such described devices and/or processes into data processing systems. That is, at least a portion of the devices and/or processes described herein may be integrated into a data processing system via a reasonable amount of experimentation. Those having skill in the art will recognize that a typical data processing system may generally include one or more of a system unit housing, a video display device, a memory such as volatile and non-volatile memory, processors such as microprocessors and digital signal processors, computational entities such as operating systems, drivers, graphical user interfaces, and applications programs, one or more interaction devices, such as a touch pad or screen, and/or control systems including feedback loops and control motors (e.g., feedback for sensing position and/or velocity, control motors for moving and/or adjusting components and/or quantities). A typical data processing system may be implemented utilizing any suitable commercially available components, such as those typically found in data computing/communication and/or network computing/communication systems.

The herein described subj ect matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality may be achieved. Hence, any two components herein combined to achieve a particular functionality may be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated may also be viewed as being "operably connected", or "operably coupled", to each other to achieve the desired functionality, and any two components capable of being so associated may also be viewed as being "operably couplable" to each other to achieve the desired functionality.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, where only one item is intended, the term "single" or similar language may be used. As an aid to understanding, the following appended claims and/or the descriptions herein may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should be interpreted to mean "at least one" or "one or more"). The same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. " Further, the terms "any of" followed by a listing of a plurality of items and/or a plurality of categories of items, as used herein, are intended to include "any of," "any combination of," "any multiple of," and/or "any combination of multiples of" the items and/or the categories of items, individually or in conjunction with other items and/or other categories of items. Moreover, as used herein, the term "set" is intended to include any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero.

Claim 1:
A method implemented in a first wireless transmit/receive unit, WTRU, the method comprising: receiving (<NUM>), from a second WTRU, a first sidelink transmission comprising a first information indicating an amount of time for the first WTRU to refrain from transmitting, to the second WTRU;
determining (<NUM>) to reselect to a third WTRU responsive to receiving the first information and based on a second sidelink transmission from the third WTRU;
establishing (<NUM>) a connection with the third WTRU; and characterised by
transmitting (<NUM>), to the third WTRU, a third sidelink transmission comprising a second information indicating congestion as a cause for the reselection.