Relay radio resource control (RRC) connection initiation procedure management

Abstract

A remote terminal calculates an extended Radio Resource Control (RRC) timer for an RRC connection initiation procedure through a relay communication link where extended RRC timer is based on a standard RRC timer and a number of hops in the relay communication link. The RRC connection initiation procedure may be an RRC Setup procedure, an RRC Reestablishment procedure, or an RRC Resume procedure. The standard RRC timer used for the calculation may be a default RRC timer or a remote configured RRC timer.

Description

TUTL 00411 PC-1 -RELAY RADIO RESOURCE CONTROL (RRC) CONNECTION INITIATION PROCEDURE MANAGEMENTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to Provisional Application No. 63 / 717,573, entitled “Reestablishment Procedures Under Multihop Relay” and filed November 07, 2024, assigned to the assignee hereof and hereby expressly incorporated by reference in its entirety.FIELD

[0002] This invention generally relates to wireless communications and more particularly to relay Radio Resource Control (RRC) connection initiation procedure management.BACKGROUND

[0003] Many wireless communication systems that employ several base stations (network nodes) that provide wireless service to terminals (user equipment (UE) devices) enable sidelink communication between two or more terminals where the terminals can communicate directly with other terminals. In addition, one or more terminal can be used as relay devices to form relay communication links between terminal and a cell of a base station or between a source UE device and a destination UE device. A relayed connection between a remote UE and the network through a relay device is often referred to as a UE-to-Network (U2N) link. The U2N link includes a PC5 link between the relay device and the remote UE and Uu link between the relay device and a cell of a base station in the network. Accordingly, a remote terminal (remote UE) may be connected to a cell of a network node through one or more intermediate relay terminals (relay UEs) forming the U2N link. The relay terminal directly connected to the cell is typically referred to as the last relay terminal or last relay UE (LRU). In some situations, multiple relay terminals can form a connection from the remote terminal toTUTL 00411 PC-2- the network. Such an arrangement is typically referred to as a multi-hop relay communication link where each relay terminal provides one hop.

[0004] In some conventional systems, the U2N communication links use a Sidelink Relay Adaptation Protocol (SRAP) defined by one or more revisions of the 3rdGeneration Partnership Project (3GPP) standards to transmit control and data signals over the PC5 link and the llu link. The SRAP is used to perform bearer mapping (signaling radio bearers (SRBs) and data radio bearers (DRBs)) between the two links. For U2N relays, a local Remote UE ID is included in both the PC5 SRAP header and the Uu SRAP header. The Layer 2 (L2) U2N Relay UE is configured by the gNB (network node) with the local Remote UE ID to be used in SRAP headers. In some situations, the U2N communication link may include more than one relay terminal.

[0005] In conventional systems, terminals establish, reestablish, or resume connections to a cell of a network. In accordance with 3GPP standards, for example, a terminal may be in one of three Radio Resource Control (RRC) states when the terminal attempts to connect or reconnect to a cell of the network. When in an RRC IDLE state, a terminal establishes a new connection using an RRC setup procedure. When a terminal is in an RRC CONNECTED state and the link fails, the terminal restores the connection through an RRC reestablishment procedure. When a terminal is in an INACTIVE state, the terminal resumes the suspended connection using an RRC resume procedure. Systems typically require the terminal to initiate a timer with a specified timer value for each of the procedures when the procedure is initiated and to determine that the procedure has failed unless a positive RRC connection initiation response message is received from the cell before the timer expires. A Setup message can be considered to be a positive RRC connection initiation response to a RRC reestablishment request. The timer may be stopped before expiration in response to a negative response (Release message, failure notification, etc.). Therefore, the procedure is considered unsuccessful when a negative response is received and is considered unsuccessful in response to expiration of the timer. The procedure is considered successful and the timer is stopped when a positive response is received.TUTL 00411 PC-3-SUMMARY

[0006] A remote terminal calculates an extended Radio Resource Control (RRC) timer for an RRC connection initiation procedure through a relay communication link where extended RRC timer is based on a standard RRC timer and a number of hops in the relay communication link. The RRC connection initiation procedure may be an RRC Setup procedure, an RRC Reestablishment procedure, or an RRC Resume procedure. The standard RRC timer used for the calculation may be a default RRC timer or a remote configured RRC timer.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 A is a block diagram of an example of a communication system where a child terminal invokes an extended timer for a Radio Resource Control (RRC) connection initiation procedure.

[0008] FIG. 1 B is a block diagram of an example of a communication system where an intermediate relay terminal performs a reestablishment procedure to establish a relay communication link for a child terminal while the child terminal suspends data transmission in response to a notification from the intermediate relay terminal.

[0009] FIG. 2 is a block diagram of an example of a base station suitable for use as the network node providing the serving cell.

[0010] FIG. 3 is a block diagram of an example of a UE device suitable for use as each of the terminals including remote terminals and relay terminals.

[0011] FIG. 4A is a message flow diagram for an example where a remote terminal, such as the child terminal, uses an extended T300 (T300A) timer when performing an RRC Setup procedure to establish a relay communication link.

[0012] FIG. 4B is a message flow diagram for an example where a remote terminal, such as the child terminal, uses an extended T301 (T301 A) timer when performing an RRC Reestablishment procedure to reestablish a relay communication link.

[0013] FIG. 4C is a message flow diagram for an example where a remote terminal, such as the child terminal, uses an extended T319 (T319E) timer when performing anTUTL 00411 PC-4-RRC Resume procedure to transition from the RRC INACTIVE state to the RRC CONNECTED state over a relay communication link.

[0014] FIG. 5A is a message flow diagram for an example where the intermediate relay terminal sends a suspend data notification to a remote terminal and performs a relay reselection procedure to establish a reestablished communication link for the child terminal after detecting a failure of the network-end portion of the initial multi-hop relay communication link between the child terminal and a network.

[0015] FIG. 5B is a message flow diagram for an example where the intermediate relay terminal sends a suspend data notification with a suspend data timer to a remote terminal and performs a relay reselection procedure to establish a reestablished communication link for the child terminal after detecting a failure of the network-end portion of the initial multi-hop relay communication link between the child terminal and a network.

[0016] FIG. 6 is a flow chart of an example of a method of performing an RRC connection initiation procedure with an extended RRC timer.

[0017] FIG. 7 is a flow chart of an example of a method of establishing a relay communication link for a child terminal after an initial multi-hop relay communication link is no longer available (e.g., fails) where the relay terminals sends a suspend data notification to the child terminal to suspend data transmissions.DETAILED DESCRIPTION

[0018] As discussed above, a relay communication link can be established between a serving cell and a remote terminal (remote user equipment (UE) device) through one or more relay terminals (relay UE devices). The relay communication link, often referred to as a UE-to-Network (U2N) communication link, includes PC5 links between the remote terminal and the relay terminal and between relay terminals when more than one relay terminal forms the U2N communication link. The remote terminal is connected through a first PC5 link to a first relay terminal. The first relay terminal is connected through a second PC5 link to the second relay terminal and the second relay terminal isTUTL 00411 PC-5- connected to the serving cell over a llu link. The relay communication link may include any number of intermediate relay terminals where a PC5 ingress link of each relay terminal is a PC5 egress link of an adjacent relay terminal. Except for the last relay terminal, therefore, each relay terminal in the U2N link has a PC5 ingress link to a terminal and a PC5 egress link to another terminal. The last relay terminal may be referred to as the U2N relay terminal or the last relay UE (LRU). The relay terminals connected within the multi-hop relay communication link between the remote terminal and the last relay terminal may be referred to as intermediate relay terminals and / or intermediate relay UEs (IRUs).

[0019] As discussed above, terminals may use timers when establishing, reestablishing, and resuming connections. For example, systems operating in accordance with 3GPP techniques initiate a T300 timer after transmitting an RRC Setup Request message to initiate establishment of a connection. A T301 timer is initiated after transmitting an RRC Reestablishment Request message to initiate reestablishment of a connection after a connection link is lost. A T319 timer is initiated after transmitting an RRC Resume Request message to initiate a resume procedure to resume a suspended connection when the terminal is in the INACTIVE state. Each timer runs until a message is received from the cell or the timer expires. A positive response message stops the timer and connection / reconnection procedure or resume procedure continues. A negative response message indicating the procedure has failed or expiration of the timer results in the terminal taking other action to establish a connection to the network. The timers facilitate stable and reliable RRC connection management in LTE and 5G NR. Although the same timers may be used in relayed links, the length of the standard timers for accessing a cell directly may be too short for relay situations, especially where the relay link is a multi-hop relay communication link. For the examples discussed herein, however, techniques are employed to increase the length of a standard timer to establish an extended timer and / or delay data transmission while a connection is reestablished.

[0020] In some situations, for example, an intermediate relay terminal determines that a portion (network-end portion) of the relay communication link from the intermediate terminal to the network has failed. The failure may be due to failure of oneTUTL 00411 PC-6- or more links in the network-end portion of the multi-hop relay communication link including the PC5 link between the intermediate relay terminal and another intermediate relay terminal, PC5 links between other intermediate relay terminals, the PC5 link to the last relay terminal, or the Uu link from the last relay terminal to the cell. As discussed herein, a failure of link is any situation where the link becomes unavailable which includes at least a radio link failure (RLF) and other situations where a relay terminal can no longer provide relay service. In conventional systems, the remote terminal applies the standard T301 timer while reestablishing the connection which may result in expiration of the timer before the positive RRC connection response message is received. In some examples discussed herein, however, the intermediate relay terminal sends a notification to the remote terminal to suspend data transmission while the intermediate relay terminal performs RRC Reestablishment. In one example, the intermediate relay terminal sends a resume data transmission notification to the remote terminal after the connection is reestablished. In another example, the notification to suspend data transmission provides a suspend data timer where the remote terminal starts the timer and resumes data transmission after the timer expires.

[0021] In another example, a terminal (remote terminal or relay terminal) applies a scaling factor to the standard timer for the particular connection / reconnection procedure to determine an extended timer value for the procedure. For at least some of the examples, the extended timer value is calculated using a scaling factor that is based on the number of hops in the relay path such the extended timer value is longer for paths with more hops. Accordingly, where the terminal initiates an RRC Setup procedure over relay communication link, the terminal uses an extended-T300 (eT300) timer value. An extended (eT301 ) timer value is used when an RRC Reestablishment procedure is initiated over a relay communication link and an extended T319 (eT319) timer value is used when an RRC Resume procedure is initiated for a relay communication link.

[0022] For the discussion herein, connection / reconnection and resume request messages, such as RRC Setup Request messages, RRC Reestablishment Request messages, and RRC Resume Request messages, are referred to as RRC connection initiation messages. Connection / reconnection and resume procedures, such as theTUTL 00411 PC-7-RRC Setup Request procedure, RRC Reestablishment Request procedure, and RRC Resume Request procedure are referred to as RRC connection initiation procedures.

[0023] A network node is any apparatus, equipment, device, or combination of devices, on the network side of the communication system that is connected to the communication network or is part of communication network. Some examples of a network node include a base station, a node B, an E-UTRA Node B, Evolved Node B, eNodeB, eNB, a New Generation eNB (ng-eNB), a gNodeB (also known as a gNB) in new radio (NR) technology, a macro station, pico station, and a femto station. The network node may form, or be a part of, the radio access network (RAN) that provides a connection between the core network and terminal communication devices. A RAN may be organized into three functional blocks including a Radio Unit (RU), a Distributed Unit (DU) and a Centralized Unit (CU). The RU transmits, receives, amplifies, and digitizes radio frequency signals and typically located near, or integrated into, the antenna. The DU and CU perform computations and / or processing to send and receive digitalized radio signals to and from the core network. The DU is typically located at or near the RU and the CU may be closer to the core network. The infrastructure or connection between the RU and the DU is often referred to as fronthaul and the infrastructure or connection between the DU and the CU is often referred to as a midhaul. The communication node, therefore, may perform the functions of one or more of the RU, DU and / or CU depending on the particular implementation.

[0024] A terminal communication device (terminal), such as a remote terminal and a relay terminal, is a communication device on the terminal side of the communication system and is sometimes referred to as user equipment (UE), a UE device, a terminal device, wireless mobile device, wireless communication device and other terms. Some examples of a terminal communication device include a mobile phone, a smart phone, a personal digital assistant (PDA), tablet, and laptop computer. In some situations, the terminal communication device is a machine type communication (MTC) communication device or Internet-of-Things (IOT) device. In addition, the terminal communication device may be, or may be a part of, a wearable device or a vehicle where the vehicle may be terrestrial vehicle, watercraft, or aircraft (including unmanned aerial vehicles).TUTL 00411 PC-8-The terminal communication device, therefore, is any fixed, mobile, or portable equipment that performs the functions of the terminal device described herein.

[0025] A parent terminal is a terminal that is connected to a child terminal where the parent terminal is typically closer within the multi-hop communication link to the cell of the network node. The parent terminal, therefore, has one less hop to the network than the child terminal. For example, an intermediate relay terminal is a child terminal of a U2N relay terminal that is Uu connected to the cell of the network node and the U2N relay terminal is parent terminal of the intermediate relay terminal. Similarly, a remote terminal is a child terminal of an intermediate relay terminal and the intermediate relay terminal is parent terminal of the remote terminal.

[0026] An access node is a terminal or a cell that provides access to the network. Accordingly, a cell may be an access node for a terminal. A U2N relay terminal may be an access node as well as an intermediate relay terminal that is connected (or can connect) to the cell via a U2N relay terminal or via one or more intermediate relay terminals and a U2N relay terminal.

[0027] FIG. 1 A is a block diagram of an example of a communication system 10 where a child terminal 12 invokes an extended timer 14 for a Radio Resource Control (RRC) connection initiation procedure. Depending in the particular situation, the child terminal 12 invokes a procedure to either establish, reestablish, or resume communication over a relay communication link 16 to a cell 18 of the network 20. For the examples, therefore, the RRC connection initiation procedure may be an RRC Setup procedure, an RRC Reestablishment procedure, or an RRC Resume procedure. The relay communication link 16 includes at least one relay terminal (21 , 22, 23). In FIG. 1 A, the child terminal 12 is connected to a first relay terminal 21 over a first PC5 link 24, a second relay terminal 22 is connected to the first relay terminal 12 over a second PC5 link 26, and a third relay terminal 23 is connected to the second relay terminal 22 over a third PC5 link 28. The first relay terminal 21 and the second relay terminal 22 may be referred to as an intermediate relay terminal (IRT) or intermediate relay UE (IRU). The third relay terminal 23 is a U2N relay terminal connected to cell over a Uu link and may be referred to as a last relay terminal (RLT) or last relay UE (LRU). The last relay terminal 23, therefore, is connected to the cell 18 of the networkTUTL 00411 PC-9-20 over a llu link 30. The second relay terminal 22 and the second PC5 link 28 are shown with dashed lines to indicate that the second terminal 22 may not be present in some situations and that additional relay terminals may be connected within the relay communication link 16. The wireless link from a relay terminal to the cell is considered a hop. Therefore, where the relay communication link includes three relay terminals 21 , 22, 23, the hop count (or number of hops) from the child terminal 12 to the cell is equal to three. The hop count at each relay terminal is equal to the hop count of the parent relay terminal plus one. Therefore, the hop count for the third relay terminal (last relay terminal) 23 is 1 , the hop count for the second relay terminal 22 is equal to 2, and the hop count for the first relay terminal 21 is equal to 3. The hop count for the relay communication path 16 is generically referred to as “N” and is equal to 3 where the relay communication path 16 includes three relay terminals. Although the example of FIG. 1 A includes a multi-hop relay communication link with multiple relay terminals, the techniques discussed herein may be applied to situations where the child terminal 12 is directly connected to last relay terminal 23 and the hop count is equal to 1 .

[0028] For the examples of FIG. 1 A, each relay terminal 21 , 22, 23 transmits a sidelink (SL) discovery signal that includes a hop count indicator indicating the hop count of the relay terminal transmitting the discovery message. Accordingly, the child terminal 12 receives a SL discovery signal (discovery message) 32 that includes the hop count of the first relay terminal 21 . For the examples, the child terminal 12 determines an extended RRC timer value for the RRC connection initiation procedure based on the number of hops and the standard timer value associated with the connection initiation procedure. In the examples, the standard RRC timer value is multiplied by the number of hops to determine the extended RRC timer value. The standard timer value may be the default timer value for accessing the network 20 directly through a cell or may be a configured sidelink relay timer value (remote configured relay timer) for use by remote terminals accessing the network 20 through a relay communication path to a cell. In some situations, the network may monitor data related to failure reports to determine a preferred configured sidelink relay timer value.In other words, the network may scale, or otherwise adjust, the configured sidelink relay timer value (remote configured relay timer) based on complied performance results ofTUTL 00411 PC-10- the connection procedures of remote terminals. In other situations, the configured sidelink relay timer value is the default timer value lengthened by a set time period to address the additional time required for communications through a PC5 connection and the Uu connection. In other examples, the extended timer value may be based on a scaling factor applied by the remote terminal (child terminal).

[0029] For the examples herein, the child terminal uses the configured sidelink relay timer received in SIB12 to determine the extended timer value when the configured sidelink relay timer value is available. If the configured sidelink relay timer value is not received (not available), the child terminal uses the default timer value in determining the extended timer value. In at least some situations, the information in the SIB12 is provided in response to the child terminal transmitting an SIB request in a RemoteUEInformationSidelink message.

[0030] The extended timer value is started when the connection request message (RRC connection initiation message) 34 is transmitted. The timer runs until it is stopped because of an event or until it expires. If the extended timer expires before a positive connection request response 36 is received, the child terminal 12 determines that the connection procedure has failed.

[0031] In one scenario, the child terminal 12 establishes a new connection to the network via the relay communication path. After performing relay selection and selecting the relay communication path 16 to connect to the network 20, the child terminal 12 transmits an RRC Setup Request message to the cell via the relay communication path 16. For this scenario, therefore, the connection request message 34 is an RRC Setup Request message. The child terminal 12 determines the extended T300 (T300E) timer based on the standard timer for Setup (T300) and the hop count (N) of the relay communication path 16. The standard T300 timer is received in a System Information Broadcast (SIB) and may be the default standard T300 timer value for directly accessing a cell or may be a configured sidelink relay T300 timer value. For example, the default standard T300 timer may be received in SIB1 from the parent terminal (first terminal 21 ) in the relay communication path where the SIB1 is relayed to its child terminal in a UuMessageTransferSidelink message. The configured sidelink relay T300TUTL 00411 PC-11- timer value may be received in SIB12 from the parent terminal (first relay terminal 21 ) in the relay communication path 16.

[0032] The child terminal 12 starts the T300E timer when transmitting the RRC Setup Request message. The T300E runs until it expires unless it is stopped because of one of several events. For example, the timer is stopped when an RRC Setup message or a RRC Reject message is received from the cell via the relay communication path. The T300E timer is also stopped when the child terminal performs cell reselection or relay (re)selection. In some situations, the child terminal 12 may be functioning as an intermediate relay terminal for a remote terminal (not shown in FIG.1 A). The T300E timer is also stopped if such a remote terminal performs relay (re)selection. When the connection attempt is aborted by higher layers, the T300E timer is stopped. If no such events occur before the T300E timer expires, the connection attempt is considered to have failed. In response, the child terminal executes tasks specified by the 3GPP specification for remote terminal RRC Setup failure. If the RRC Setup procedure fails, the child terminal performs relay reselection, followed by another attempt to perform RRC establishment over a new path. Where the child terminal is also serving as a relay terminal, the child terminal also sends a notification message to its child terminal with an indication of the failed connection. Where the RRC Setup message is received, the child terminal continues with the connection procedure (RRC Setup procedure) by transmitting an RRC Setup Complete message to the cell via the relay communication path. Accordingly, the positive connection request response is the RRC Setup message for this scenario.

[0033] In another scenario, the child terminal 12 reestablishes a connection to the network via the relay communication path 16. After determining that an original communication path has failed, performing relay reselection, and selecting the relay communication path 16 to connect to the network 20, the child terminal 12 transmits an RRC Setup Reestablishment message to the cell 18 via the relay communication path 16. For this scenario, therefore, the connection request message 34 is an RRC Reestablishment Request message. The child terminal 12 determines the extended T301 (T301 E) timer based on the standard timer for reestablishment (T301) and the hop count (N) of the relay communication path 16. The standard T301 timer is received in aTUTL 00411 PC-12-System Information Broadcast (SIB) and may be the default standard T301 timer value for directly accessing a cell or may be a configured sidelink relay T301 timer value. For example, the default standard T301 timer may be received in SIB1 from the parent terminal (first terminal 21 ) in the relay communication path where the SIB1 is received in a UuMessageTransferSidelink message. The configured sidelink relay T301 timer value may be received in SIB12 from the parent terminal (first relay terminal 21 ) within the relay communication path 16. In some situations, SIB12 timer information is provided in response to an SIB request received from the child terminal in a RemoteUEInformationSidelink message comprising the SIB request.

[0034] The child terminal 12 starts the T301 E timer when transmitting the RRC Setup Reestablishment message. The T301 E runs until it expires unless it is stopped in response to a received message or in response to a detected event. For example, the timer is stopped when an RRC Reestablishment message or an RRC Setup message is received from the cell via the relay communication path. The T301 E timer is also stopped when the child terminal determines that the cell or a relay terminal in the relay communication path 16 has become unsuitable for communication. The T301 E timer is stopped in response to reception of a sidelink notification message indicating either a relay handover (e.g., relayUE-HO) or a relay cell reselection (e.g., relayUE- CellReselection) is being performed.

[0035] If the T301 E timer expires, the connection attempt is considered to have failed. In response, the child terminal 12 transitions to the RRC IDLE state. Where an RRC Reestablishment message is received, the child terminal 12 continues with the connection procedure (RRC Reestablishment procedure) by transmitting an RRC Reestablishment Complete message to the cell via the relay communication path 16. Where an RRC Setup message is received, the child terminal 12 continues with the connection procedure (RRC Setup procedure) by transmitting an RRC Setup Complete message to the cell via the relay communication path 12. Accordingly, the positive connection request response message 36 is either the RRC Reestablishment message or the RRC Setup message for this scenario.

[0036] In yet another scenario, the child terminal 12 resumes a connection to the network via the relay communication path 16. While in the RRC INACTIVE state, theTUTL 00411 PC-13- child terminal 12 determines that the connection over the relay communication path 16 to the cell 18 should be resumed. In response, the child terminal 12 transmits an RRC Resume Request message to the cell 18 via the relay communication path 16. For this scenario, therefore, the connection request message 34 is an RRC Resume Request message. The child terminal 12 determines the extended T319 (T319E) timer based on the standard timer for reestablishment (T319) and the hop count (N) of the relay communication path 16. The standard T319 timer is received in a System Information Broadcast (SIB) and may be the default standard T319 timer value for directly accessing a cell or may be a configured sidelink relay T319 timer (remote configured T319) value. For example, the default standard T319 timer may be received in SIB1 from the parent terminal (first terminal 21 ) in the relay communication path where the SIB1 is received in a UuMessageTransferSidelink message. The configured sidelink relay T319 timer value may be received in SIB12 from the parent terminal (first relay terminal 21 ) within the relay communication path 16.

[0037] The child terminal 12 starts the T319E timer when transmitting the RRC Setup Resume Request message. The T319E runs until it expires unless it is stopped in response to a received message or in response to a detected event. For example, the timer is stopped when an RRC Resume message, RRC Reject message, RRC Release message, or an RRC Reestablishment message is received from the cell via the relay communication path. The T319E timer is also stopped when the child terminal determines that the cell or a relay terminal in the relay communication path 16 has become unsuitable for communication or if the upper layers abort the resume procedure.

[0038] If the T319E timer expires, the connection attempt is considered to have failed. In response, the child terminal transitions to the RRC IDLE state. Where an RRC Resume message is received, the child terminal continues with the connection procedure (RRC Resume procedure) by transmitting an RRC Resume Complete message to the cell via the relay communication path. Accordingly, the positive connection request response message 36 is either the RRC Resume message or a RRC Setup message.TUTL 00411 PC-14-

[0039] In situations where the network monitors data related to failure reports to adjust the remote configured RRC timer, an example of suitable technique for providing data to the network includes configuring minimizing drive test (MDT) measurement reports that providing information regarding failures relayed to RRC timers. Some examples of MDT report information include 1) a cause of failure indicator indicating the cause of the failure is due to T300 timer expiry; 2) a cause of failure indicator indicating the cause of the failure is due to T301 timer expiry; 3) a cause of failure indicator indicating the cause of the failure is due to T319 timer expiry) 4) the T300 timer value;5) the T301 timer value; 6) the T319 timer value; 7) a T300 standard timer value source indicator indicating whether the standard T300 value used for calculating the extended T300 timer (T300E) value was based on a remote configured timer value from s / - TimersAndConstantsRemoteUE (from SIB12) or a default timer value from UE- TimersAndConstants (from SIB1 ); 8) a T301 standard timer value source indicator indicating whether the standard T301 value used for calculating the extended T301 timer (T301 E) value was based on a remote configured timer value from sl- TimersAndConstantsRemoteUE (from SIB12) or a default timer value from UE- TimersAndConstants (from SIB1 ) 9) a T319 standard timer value source indicator indicating whether the standard T319 value used for calculating the extended T319 timer (T319E) value was based on a remote configured timer value from sl- TimersAndConstantsRemoteUE (from SIB12) or a default timer value from UE- TimersAndConstants (from SIB1 ); 10) the calculated extended T300 (T300E) value; 11 ) the calculated extended T301 (T301 E) value; 12) the calculated extended T319 (T319E) value; and 13) the number of hops. Some indicators can be omitted in some situations and / or additional indicators can be included.

[0040] FIG. 1 B is a block diagram of an example of a communication system 100 where an intermediate relay terminal 102 performs a reestablishment procedure to establish a relay communication link (reestablished relay communication link) 104 for a child terminal 106 while the child terminal 106 suspends data transmission in response to a notification 107 from the intermediate relay terminal 102. The intermediate relay terminal 102 facilitates the initial relay communication link 110 between the child terminal 106 and the network 112 where the child terminal 106 may be anotherTUTL 00411 PC-15- intermediate relay terminal or a remote terminal when determining that an initial relay communication link network-end portion (network-end portion) 108 of the initial relay communication link 110 is no longer suitable for communication. In response to determining the network-end portion 108 has failed, or is otherwise unavailable, the intermediate relay terminal 102 sends as suspend data notification 107 to the child terminal 106 and initiates a reestablishment procedure to establish a relay communication link (reestablished relay communication link) 104. The relay communication link 104 includes a PC5 link 114 between the intermediate relay terminal 102 and the child terminal 106 and a reestablished relay communication link networkend portion (network-end portion) 115 between the intermediate relay terminal 102 and the network 112. The communication link network-end portion 115 may include any number of other intermediate relay terminals 116, a last relay terminal (U2N relay terminal) 118, and cell 120 connected to the network 112. In some situations, the intermediate relay terminal 102 is connected directly to the last relay terminal 118. The last relay terminal 118 is connected to a cell 120 through a Uu link 122. Where the relay communication link network-end portion 115 includes at least one other intermediate relay terminal 114, the intermediate relay terminal 102 is connected to a parent intermediate relay terminal 116 via a PC5 link 124. The parent intermediate relay terminal 116 is connected via a PC5 link 126 to its parent terminal which may be another intermediate terminal or the last relay terminal 118. Where the relay communication link network-end portion 115 does not include any other intermediate relay terminals in addition to the intermediate relay terminal 102, the intermediate relay terminal 102 is connected to the last relay terminal 118 over a PC5 communication link 128.

[0041] While facilitating the initial relay communication link 110, the intermediate relay terminal 102 determines the initial relay communication link network-end portion 108 has failed (or is otherwise no longer available). The determination may be based on detecting a failure of the PC5 link to the parent terminal or receiving a notification from another terminal. The failure notification may be generated by the parent terminal in response to a failure notice received at the parent terminal from its parent terminal.TUTL 00411 PC-16-

[0042] The intermediate relay terminal 102 sends a suspend data notification 107 to child terminal 106 and performs relay reselection to identify a suitable relay terminal for reestablishing a connection to the network 112 via the relay communication link 104. In some situations, the relay communication link 104 includes the same number of relay terminals as the initial relay communication link 110 and is connected to the network via the same cell 120 as the initial relay communication link 110. In other situations, the number of relay terminal and / or the selected cell 120 may be different from the initial relay communication link 110. As discussed below in further detail, the intermediate may take different action depending on the cell and number of hops.

[0043] In one example, the suspend data notification 107 provides a suspend data timer value for the child terminal to activate a suspend data timer where the child terminal resumes data transmission after the suspend data timer expires. In another example, the suspend data notification 107 indicates that the child terminal should suspend data transmission and the intermediate relay terminal 102 sends a resume data notification 130 notifying the child terminal 106 that data transmission can resume. Accordingly, the child terminal 106 suspends data transmission during a suspend data phase 132. In both examples, the suspend data phase can be interrupted by one or more events or messages. In certain situations, for example, the intermediate relay terminal 102 may determine that the child terminal 106 should perform relay reselection and reestablishment and sends a notification message to the child terminal 106. In other situations, the child terminal 106 may determine that the PC5 link to the intermediate terminal has failed. Where the suspend data phase is based on the suspend data timer, the child terminal 106 stops the timer and takes appropriate action in response to a notification or event. As discussed below, the intermediate relay terminal 102 also sends a failure notification if the reestablished link fails to meet hop count and serving cell requirements. For the implementation using a suspend data timer, the failure notification is sent before expiration of the timer.

[0044] After selecting the relay communication link network end portion 115, the intermediate relay terminal 102 determines whether the relay communication link network-end portion 115 includes a different cell from the cell used in the initial relay communication link network-end portion 108 and whether the total number of hops forTUTL 00411 PC-17- the relay communication link network-end portion 115 is greater than the total number of hops of the initial relay communication link network-end portion 108. If either is true, the intermediate relay terminal 102 sends failure notification message to the child terminal 106 invoking the child terminal 106 to perform relay reselection followed by a reestablishment procedure. If the cell is the same and the number of hops is the same or less than the initial relay communication link network-end portion 108, the intermediate relay terminal 102 does not send a failure notification.

[0045] After establishing a PC5 connection to its parent terminal within the relay communication link network-end portion 108, the intermediate relay terminal 102 initiates the reestablishment procedure by transmitting a reestablishment request message 134 to the cell 120 via the relay communication link network-end portion 108. For the example, the relay communication link includes the intermediate relay terminal 116 and the last relay terminal 118. Accordingly, the reestablishment request message 134 is sent to the intermediate relay terminal (IRT) 116 and forwarded to the cell 120 via the IRT 116 and the LRT 118. For the examples, the reestablishment request messages are RRC reestablishment request messages transmitted via SL-RLC1 channel between terminals and via the SRB1 channel to the serving cell of the last relay terminal of the alternate communication link. The cell 120 responds with a RRC Reestablishment message 136 where reestablishment is granted and the message is forwarded through the relay communication link network-end portion 115 to the intermediate relay terminal 102. After sending a reestablishment complete message 138, the intermediate relay terminal 102 sends a resume data notification 130 to the child terminal for the examples where a timer is not used. Otherwise, the intermediate relay terminal 102 starts sending and receiving data to and from the child terminal after the timer expires. For the examples herein, the intermediate relay terminal also initiates the suspend data timer after sending the suspend data notification with the timer. In some situations, the intermediate relay terminal 102 may send downlink data to the child terminal before expiration of the timer, where the ability of the child terminal to receive the downlink data may be based the terminal implementation. As part of the management downlink data before timer expiration, the intermediate relay terminal may send a status query message to the child terminal.TUTL 00411 PC-18-

[0046] A discussed above, the cell 120 facilitating connection to the network 112 may the same cell that facilitated the initial multi-hop relay communication link 110 connection to the network 112 or may be a new, different cell where the new cell may be provided by the same network node (gNB) that provided the initial cell or may be provided by another network node (gNB). Where the cell 120 is a new, different cell from the initial cell, the intermediate relay terminal 102 sends a failure notification to the child terminal invoking the child terminal 106 to perform relay reselection and reestablishment. The intermediate relay terminal 102 also sends a failure notification to the child terminal 106 when the number of hops of the reestablished relay communication link network-end portion 115 is greater than the number of hops of the initial relay communication link network-end portion 108.

[0047] FIG. 2 is a block diagram of an example of a base station 200 suitable for use as the network node providing the cell 120 and the network node providing the cell 18. The base station 200 includes a controller 204, transceiver 205 that includes a transmitter 206 and receiver 208, and an antenna 210, as well as other electronics, hardware, and code. The base station 200 is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to the network nodes providing cells and base station 200 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a single device, and the functions described as performed in any single device may be implemented over several devices. The base station 200 may be a fixed device or apparatus that is installed at a particular location at the time of system deployment. Examples of such equipment include fixed base stations or fixed transceiver stations. Although the base station 200 may be referred to by different terms, the base station 200 is typically referred to as a gNodeB or gNB when operating in accordance with one or more communication specifications of the 3GPP V2X operation. In some situations, the base station 200 may be mobile equipment that is temporarily installed at a particular location. Some examples of such equipment include mobile transceiver stations that may include power generating equipment such as electric generators, solar panels, and / or batteries. Larger and heavier versions of such equipment may be transported by trailer. In still otherTUTL 00411 PC-19- situations, the base station 200 may be a portable device that is not fixed to any particular location.

[0048] The controller 204 includes any combination of hardware, software, and / or firmware for executing the functions described herein as well as facilitating the overall functionality of the base station 200. An example of a suitable controller 204 includes code running on a microprocessor or processor arrangement connected to memory. The transmitter 206 includes electronics configured to transmit wireless signals. In some situations, the transmitter 206 may include multiple transmitters. The receiver 208 includes electronics configured to receive wireless signals. In some situations, the receiver 208 may include multiple receivers. The receiver 208 may receive signals through multiple antennas or through a selected antenna of a plurality of antennas of the antenna 210. The antenna 210 may include separate transmit and receive antennas or separate arrays in some situations.

[0049] The transmitter 206 and receiver 208 in the example of FIG. 2 perform radio frequency (RF) processing including modulation and demodulation. The receiver 208, therefore, may include components such as low noise amplifiers (LNAs) and filters. The transmitter 206 may include filters and amplifiers. Other components may include isolators, matching circuits, and other RF components. These components in combination or cooperation with other components perform the base station functions. The required components may depend on the particular functionality required by the base station.

[0050] The transmitter 206 includes a modulator (not shown), and the receiver 208 includes a demodulator (not shown). The modulator modulates the signals to be transmitted as part of the downlink signals and can apply any one of a plurality of modulation orders. The demodulator demodulates any uplink signals received at the base station 200 in accordance with one of a plurality of modulation orders.

[0051] The base station 200 includes a communication interface 212 for transmitting and receiving messages with other base stations such as the network nodes providing target cells and / candidate target cells. The communication interface 212 may be connected to a backhaul or network enabling communication with other base stations. In some situations, the link between base stations may include at least some wirelessTUTL 00411 PC-20- portions. The communication interface 212, therefore, may include wireless communication functionality and may utilize some of the components of the transmitter 206 and / or receiver 208.

[0052] FIG. 3 is a block diagram of an example of a UE device 300 suitable for use as each of the terminals including child terminals, parent terminals, last relay terminals, remote terminals, and relay terminals, such as the intermediate relay terminals 21 , 22, 102, the child terminal 12, 106, the last relay terminal 23, 118 and other intermediate relay terminals. In some examples, the UE device 300 is any wireless communication device such as a mobile phone, a transceiver modem, a personal digital assistant (PDA), a tablet, or a smartphone. In other examples, the UE device 300 is a machine type communication (MTC) communication device or Intemet-of-Things (IOT) device. The UE device 300, therefore is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to UE device 300 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a single device, and the functions described as performed in any single device may be implemented over several devices.

[0053] The UE device 300 includes at least a controller 302 and a transceiver 303 that includes a transmitter 304 and a receiver 306. The controller 302 includes any combination of hardware, software, and / or firmware for executing the functions described herein as well as facilitating the overall functionality of a communication device. An example of a suitable controller 302 includes code running on a microprocessor or processor arrangement connected to memory 310. The transmitter 304 includes electronics configured to transmit wireless signals. In some situations, the transmitter 304 may include multiple transmitters. The receiver 306 includes electronics configured to receive wireless signals. In some situations, the receiver 306 may include multiple receivers. The receiver 306 and transmitter 304 receive and transmit signals, respectively, through the antenna 308. The antenna 308 may include separate transmit and receive antennas. In some circumstances, the antenna 308 may include multiple transmit and receive antennas.TUTL 00411 PC-21-

[0054] The transmitter 304 and receiver 306 in the example of FIG. 3 perform radio frequency (RF) processing including modulation and demodulation. The receiver 306, therefore, may include components such as low noise amplifiers (LNAs) and filters. The transmitter 304 may include filters and amplifiers. Other components may include isolators, matching circuits, and other RF components. These components in combination or cooperation with other components perform the communication device functions. The required components may depend on the particular functionality required by the communication device.

[0055] The transmitter 304 includes a modulator (not shown), and the receiver 306 includes a demodulator (not shown). The modulator can apply any one of a plurality of modulation orders to modulate the signals to be transmitted as part of the uplink signals. The demodulator demodulates the downlink signals in accordance with one of a plurality of modulation orders.

[0056] The UE device 300 is capable of transmitting and receiving sidelink signals to and from other UE devices as well as communicating with a base station. The controller 302, in conjunction with the receiver 306, measures signals, such as discovery signals, transmitted by nearby UE devices to generate the neighbor list that includes neighbor UE devices within the maximum distance. The neighbor list is stored in the memory 310 and transmitted to a base station 200 when the UE device 300 is a reporting UE device.

[0057] FIG. 4A is a message flow diagram 400 for an example where a remote terminal 401 , such as the child terminal 12, uses an extended T300 (T300A) timer when performing an RRC Setup procedure to establish a relay communication link. For the example of FIG. 4A, the remote terminal 401 establishes a relay communication link to a serving cell 18 via an intermediate relay terminal 21 and last relay terminal 23. For the example, therefore, the relay communication link includes two relay terminals. The techniques discussed with reference to FIG. 4A, however, may be applied to relay communication links with any number of relay terminals.

[0058] At transmission 404, the cell 18 broadcasts the SIB1 with the default RRC timers including the default T300, T301 , and T319 timer values. For example, the default RRC timers used for accessing a cell for the RRC connection initiationTUTL 00411 PC-22- procedures are included in ue-TimersAndConstants. The last relay terminal 23 receives and decodes the SIB1 to determine the default RRC timers. The information is stored in memory at the last relay terminal 23.

[0059] At transmission 405, the cell 18 transmits an RRC message with SIB12 information including remote configured RRC timer values. When the last relay terminal 23 is in the IDLE and INACTIVE states, it receives SIBs by monitoring broadcasts from the cell 18. When the last relay terminal 23 is in the CONNECTED state, it receives the SIBs via a RRC Reconfiguration message. Other than SIB1 , SIBs such as SIB12, are not always broadcasted and are provided in response to a SIB request from the terminal. For example, when the last relay terminal 23 is in RRC CONNECTED, it sends a DedicatedSIBRequest to the cell 18. . The information is stored in memory at the last relay terminal 23.

[0060] At event 406, a PC5 connection is established between the intermediate relay terminal 21 and the last relay terminal 23. In the interest of clarity and brevity, transmissions and events of the establishment of the PC5 connection are omitted in the example. For example, the intermediate relay terminal may perform relay selection or reselection, receive discovery signals from one or more relay terminals and cells in establishing the PC5 connection. The intermediate relay terminal 21 receives the hop count from the last relay terminal 23 via the discovery message in the example.

[0061] After the PC5 connection is established, the last relay terminal 23 provides RRC timer information to the intermediate relay terminal 21 . At transmission 407, the last relay terminal 23 transmits a sidelink RRC message with SIB1 information including default RRC timer values. When the intermediate relay terminal 21 is in RRC CONN, it can receive SIB1 via the RRC Reconfiguration message forwarded by the last relay terminal 23. If the intermediate relay terminal 21 is in IDLE / INACTIVE, the last relay terminal 23 sends the stored SIB1 information intermediate relay terminal 21 using a UuMessageTransferSidelink message. The last relay terminal 23 transmits the UuMessageTransferSidelink message to the intermediate relay terminal 21 as a sidelink RRC signaling transmission over the PC5 interface, carrying system information including SIB1 and timer configuration parameters for downstream (child terminals). The information is stored in memory at the intermediate relay terminal 21 .TUTL 00411 PC-23-

[0062] At transmission 408, the last relay terminal 23 transmits SIB12 information including remote configured RRC timer values to the intermediate relay terminal. The intermediate relay terminal 21 receives the SIB12 information in one of two ways. When the intermediate relay terminal 21 is in RRC CONN, it can receive SIB12 via the RRC Reconfiguration message forwarded by the last relay terminal 23. If the intermediate relay terminal 21 is in IDLE / INACTIVE, the last relay terminal 23 sends the stored SIB12 information intermediate relay terminal 21 using a UuMessageTransferSidelink message.

[0063] At event 410, the remote terminal 401 initiates relay selection in order to establish a relay communication link to the cell 18. At transmission 412, a discovery message is received from the intermediate relay terminal 21. Multiple discovery signals may be received from different candidate relay terminals. The discovery message includes the hop count for the connection to the cell 18. The intermediate relay terminal 21 adds 1 to the hop count received from the last relay terminal 23. Accordingly, the hop count in the discovery message transmission 412 to the remote terminal 401 is 2 for the example.

[0064] At event 414, a PC5 connection is established between the remote terminal 401 and the intermediate relay terminal 21. In accordance with 3GPP techniques, the remote terminal 401 sends a sidelink Direct Communication Request message (a PC5- S message) to the intermediate relay terminal 21 and the intermediate relay terminal 21 sends Direct Communication Accept message.

[0065] At transmission 415, the intermediate relay terminal 21 transmits a sidelink RRC message with SIB1 information including default RRC timer values. The stored information default timer information received at the intermediate relay terminal 21 in the transmission 407 is sent to the remote terminal 401 . For example, the remote configured RRC timers used for accessing a cell for the RRC connection initiation procedures to cell are included in a System! nformationDelivery message. The intermediate relay terminal 21 transmits the UuMessageTransferSidelink message to the remote terminal 401 as a sidelink RRC signaling transmission over the PC5 interface, carrying system information including SIB1 and timer configuration parameters for downstream (child terminals).TUTL 00411 PC-24-

[0066] At transmission 416, the intermediate relay terminal 21 transmits SIB12 information including remote configured RRC timer values to the remote terminal 401 . The intermediate relay terminal 21 transmits the SIB12 information in one of two ways. When the remote terminal 401 is in RRC CONN, it can receive SIB12 via the RRC Reconfiguration message forwarded by the intermediate relay terminal 21 . If the remote terminal 21 is in IDLE / INACTIVE, the intermediate relay terminal 21 sends the stored SIB12 information to remote terminal 401 using a UuMessageTransferSidelink message.

[0067] At event 418, the remote terminal 410 calculates the extended T300 (T300E) timer value based, at least partially, on the hop count and the standard RRC timer for the RRC connection initiation procedure. The standard timer for the setup procedure may be the default T300 timer value included SIB1 or may be the remote configured T300 value included SIB12. For the example, the remote terminal 401 uses the remote configured T300 value if available to calculate the T300E. Where the remote configured T300 value is not available, the remote terminal 401 uses the default T300 value to calculate the T300E value. The T300E timer value is the product of the standard T300 value (either the default T300 value or the remote configured T300 value) and the hop count. For the example, therefore, the extended T300 value is equal to twice the remote configured T300 timer value (T300E = 2 X remote configured T300).

[0068] At transmission 420, the remote terminal 401 sends an RRC Setup Request message to the intermediate relay terminal 21. For the example, the request is transmitted using SL-RLC0 signaling. At event 422, the T300E timer is started. The T300E timer is started either simultaneously with transmission 420 or immediately after transmission 420.

[0069] At transmission 424, the intermediate relay terminal 21 forwards the RRC Setup request to cell via the last relay terminal 23 within the SidelinkUEInformation message (SUI), an RRC message. If, however, the intermediate relay terminal 21 is not yet RRC CONNECTED, the intermediate relay terminal 21 transmits is own RRC Setup Request to the cell. For the example, the intermediate relay terminal’s request is transmitted using the default SL-RLC0 signaling. Once the intermediate relay terminalTUTL 00411 PC-25-21 is RRC CONNECTED, it can include the child UE’s RRC Setup Request to the cell via the last relay UE within the SidelinkUEInformation message (Sill).

[0070] At transmission 428, the cell sends an RRC Setup message to the remote terminal 401 via the relay connection link. At transmission 430, the remote terminal 401 responds with an RRC Setup Complete message via the relay communication link. At event 432, uplink and downlink data between the remote terminal 401 and the cell 18 are exchanged.

[0071] FIG. 4B is a message flow diagram 450 for an example where a remote terminal 401 , such as the child terminal 12, uses an extended T301 (T301 A) timer when performing an RRC Reestablishment procedure to reestablish a relay communication link. For the example of FIG. 4B, the remote terminal 401 reestablishes a relay communication link to a serving cell 18 via an intermediate relay terminal 21 and last relay terminal 23. For the example, therefore, the relay communication link includes two relay terminals. The techniques discussed with reference to FIG. 4B, however, may be applied to relay communication links with any number of relay terminals. For the example of FIG. 4B, the transmissions 404-408, 412, 414-416 are performed as discussed with reference to FIG. 4A above.

[0072] At event 452, the remote terminal 401 initiates relay reselection in order to reestablish a relay communication link to the cell 18. At transmission 412, a discovery message is received from the intermediate relay terminal 21. Multiple discovery signals may be received from different candidate relay terminals. The discovery message includes the hop count for the connection to the cell. The intermediate relay terminal 21 adds 1 to the hop count received from the last relay terminal 23. Accordingly, the hop count in the discovery message transmission 412 to the remote terminal 401 is 2 for the example.

[0073] At event 454, the remote terminal 410 calculates the extended T301 (T301 E) timer value based, at least partially, on the hop count and the standard RRC timer for the RRC connection initiation procedure (Reestablishment). The standard timer for the reestablishment procedure may be the default T301 timer value included in SIB1 or may be the remote configured T301 value included SIB12. For the example, the remote terminal 401 uses the remote configured T301 value if available to calculate the T301 E.TUTL 00411 PC-26-Where the remote configured T301 value is not available, the remote terminal 401 uses the default T301 value to calculate the T301 E value. The T301 E timer value is the product of the standard T301 value (either the default T301 value or the remote configured T301 value) and the hop count. For the example, therefore, the extended T301 value is equal to twice the remote configured T301 timer value (T301 E = 2 X remote configured T301 ).

[0074] At transmission 456, the remote terminal 401 sends an RRC Reestablishment Request message to the intermediate relay terminal 21. For the example, the request is transmitted using SL-RLC1 signaling. At event 458, the T301 E timer is started. The T301 E timer is started either simultaneously with the transmission 456 or immediately after transmission 456.

[0075] At transmission 460, the intermediate relay terminal 21 forwards the RRC Reestablishment Request to the last relay terminal 23. For the example, the reestablishment request is transmitted to cell via the last relay terminal 23 within the SidelinkUEInformation message (SUI), an RRC message.

[0076] At transmission 464, the cell 18 sends an RRC Reestablishment message to the remote terminal 401 via the relay connection link. At transmission 466, the remote terminal 401 responds with an RRC Reestablishment Complete message via the relay communication link. At event 468, uplink and downlink data between the remote terminal 401 and the cell 18 are exchanged.

[0077] FIG. 4C is a message flow diagram 470 for an example where a remote terminal 401 , such as the child terminal 12, uses an extended T319 (T319E) timer when performing an RRC Resume procedure to transition from the RRC INACTIVE state to the RRC CONNECTED state over a relay communication link. For the example of FIG. 4C, the remote terminal 401 establishes a relay communication link to a serving cell 18 via an intermediate relay terminal 21 and last relay terminal 23. For the example, therefore, the relay communication link includes two relay terminals. The techniques discussed with reference to FIG. 4C, however, may be applied to relay communication links with any number of relay terminals. For the example of FIG. 4C, the transmissions 404-408, 412, 414-416 and even 410 are performed as discussed with reference to FIG. 4A above.TUTL 00411 PC-27-

[0078] At event 474, the remote terminal 401 transitions to the RRC INACTIVE state.

[0079] At event 476, the remote terminal 410 calculates the extended T319 (T319E) timer value based, at least partially, on the hop count and the standard RRC timer for the RRC connection initiation procedure (Resume). The standard timer for the resume procedure may be the default T319 timer value included in SIB1 or may be the remote configured T319 value included SIB12. For the example, the remote terminal 401 uses the remote configured T319 value if available to calculate the T319E. Where the remote configured T319 value is not available, the remote terminal 401 uses the default T319 value to calculate the T319E value. The T319E timer value is the product of the standard T319 value (either the default T319 value or the remote configured T319 value) and the hop count. For the example, therefore, the extended T319 value is equal to twice the remote configured T319 timer value (T319E - 2 X remote configured T319).

[0080] At transmission 478, the remote terminal 401 sends an RRC Resume Request message to the intermediate relay terminal 21. For the example, the request is transmitted using the default SL-RLC1 signaling. At event 480, the T319E timer is started. The T319E timer is started either simultaneously with the transmission 478 or immediately after transmission 478.

[0081] At transmission 482, the intermediate relay terminal 21 forwards the RRC Resume Request to the last relay terminal 23. For the example, the resume request is transmitted to cell via the last relay terminal 23 within the SidelinkUEInformation message (Sill), an RRC message.

[0082] At transmission 486, the cell 18 sends an RRC Resume message to the remote terminal 401 via the relay connection link. At transmission 488, the remote terminal 401 responds with an RRC Resume Complete message via the relay communication link. At event 490, uplink and downlink data between the remote terminal 401 and the cell 18 are exchanged.

[0083] FIG. 5A is a message flow diagram 500 for an example where the intermediate relay terminal 102 sends a suspend data notification to a remote terminal 502 and performs a relay reselection procedure to establish a reestablished communication link 104 for the child terminal 106 after detecting a failure of the network-end portion 108 of the initial multi-hop relay communication link 110 betweenTUTL 00411 PC-28- the child terminal 106 and a network 112. For the example of FIG. 5A, the initial multihop relay communication link 110 is between a remote terminal 401 and the network 112 where the remote terminal 502 is the child terminal 106 and the intermediate relay terminal 102 is connected to an initial last relay terminal 504 through the PC5 link 128.

[0084] At event 506, the remote terminal 106 communicates with the network through the initial multi-hop relay communication link 110 where uplink and downlink data can be transmitted and received over the link 110. Accordingly, at event 506, data is exchanged between the remote terminal 401 and the network over the initial multihop relay communication link 110 that includes two relay terminals.

[0085] At event 508, the initial last relay terminal 504 detects that the Uu link to the cell 120 has failed. At transmission 510, the initial last relay terminal 504 sends a failure notification to the intermediate terminal 102 indicating the failure was detected. In other examples, the intermediate relay terminal 102 detects a failure on the PC5 link to the initial last relay terminal 504.

[0086] At transmission 512, the intermediate relay terminal 102 sends a suspend data notification to the remote terminal 502 instructing the remote terminal 502 to suspend data transmissions to the intermediate relay terminal 102. For the example, a suspend data notification message is transmitted over the PC5 link to the remote terminal using a Notification MessageSidelink message.

[0087] At event 514, the remote terminal 502 suspends data transmissions to the intermediate relay terminal. In response to the suspend data notification message, the remote terminal 502 does not transmit data to the cell 120 over the relay communication link including the intermediate relay terminal 102. For the example for FIG. 5A, the remote terminal 502 does resume data transmissions to the intermediate relay terminal 102 until receiving a resume data notification from the intermediate relay terminal 102. In some situations, the intermediate relay terminal 102 does not send a resume data notification and sends another message invoking the remote terminal to perform relay selection. For example, where the intermediate relay terminal 102 is unable to reestablish the relay communication link, the intermediate relay terminal 102 sends a RLF notification or other message indicating that the intermediate relay terminal 102 is unable to facilitate a connection.TUTL 00411 PC-29-

[0088] At event 516, the intermediate relay terminal 102 initiates relay selection. The intermediate relay terminal 102 receives and evaluates one or more discovery messages transmitted by candidate relay terminals and / or reference signals transmitted by cells. For the example of FIG. 5A, only a single discovery message 518 transmitted from a candidate relay terminal (last relay terminal) 118 is shown in the interest of clarity and brevity. However, multiple discovery messages and reference signals may be received and evaluated. At event 520, the intermediate relay terminal selects the last relay terminal 118 for providing the network-end communication link portion 115 to the network.

[0089] At event 522, the intermediate relay terminal 102 establishes a PC5 link with the alternate last relay terminal 118. In accordance with known techniques, the intermediate relay terminal 102 and alternate last relay terminal exchange messages to establish the PC5 link.

[0090] At transmission 524, the intermediate relay terminal 102 sends an RRC Reestablishment Request to the cell 120 via the last relay terminal 118. For the example, the last relay terminal 118 is in the RRC CONNECTED state with the cell 120. Accordingly, the RRC Reestablishment Request is forwarded within the SidelinkUEInformation message (Sill), an RRC message. If, however, the last relay terminal 118 is not yet RRC CONNECTED, the last relay terminal 118 transmits is own RRC Setup Request to the cell. Once the last relay terminal 118 is RRC CONNECTED, it can include the RRC Reestablishment Request of the intermediate relay terminal 102 to the cell within the SidelinkUEInformation message (Sill). If the cell is different or if the number hops is greater than the initial relay communication link, the intermediate relay terminal 102 sends a failure notification to the remote terminal 502 invoking relay reselection. The notification should be sent prior to timer expiry.

[0091] At transmission 528, the cell 120 sends an RRC Reestablishment message to the intermediate relay terminal 102 via the last relay terminal 118. At transmission 530, the intermediate relay terminal 102 sends an RRC Reestablishment Complete message to the cell 120. The intermediate relay terminal applies the parameters provided in the RRC Reestablishment message received at transmission 528 and transmits the RRCTUTL 00411 PC-30-Reestablishment Complete message the via the last relay terminal 118 to the cell 120 to establish RRC with the cell 120.

[0092] At transmission 532, the intermediate relay terminal 102 sends a resume data notification message to the remote terminal 502. The resume data notification message indicates to the remote terminal 502 that it can resume data communication over reestablished relay communication link via intermediate relay terminal.

[0093] At event 534, data communication is resumed between the remote terminal 502 and the network over the reestablished communication link including the intermediate relay terminal 102 and the last relay terminal 118.

[0094] FIG. 5B is a message flow diagram 550 for an example where the intermediate relay terminal 102 sends a suspend data notification with a suspend data timer to a remote terminal 502 and performs a relay reselection procedure to establish a reestablished communication link 104 for the child terminal 106 after detecting a failure of the network-end portion 108 of the initial multi-hop relay communication link 110 between the child terminal 106 and a network 112. For the example of FIG. 5B, the initial multi-hop relay communication link 110 is between a remote terminal 502 and the network 112 where the remote terminal 502 is the child terminal 106 and the intermediate relay terminal 102 is connected to an initial last relay terminal 504 through the PC5 link 128.

[0095] At event 506, the remote terminal 502 communicates with the network through the initial multi-hop relay communication link 110 where uplink and downlink data can be transmitted and received over the link 110. Accordingly, at event 506, data is exchanged between the remote terminal 502 and the network over the initial multihop relay communication link 110 that includes two relay terminals.

[0096] At event 508, the initial last relay terminal 504 detects that the llu link to the cell 120 has failed. At transmission 510, the initial last relay terminal 504 sends a failure notification to the intermediate terminal 102 indicating the failure was detected. In other examples, the intermediate relay terminal 102 detects a failure on the PC5 link to the initial last relay terminal 504.

[0097] At transmission 552, the intermediate relay terminal 102 sends a suspend data notification to the remote terminal 502 instructing the remote terminal 502 toTUTL 00411 PC-31- suspend data transmissions to the intermediate relay terminal 102 for a suspend data time period. For the example, a suspend data notification message is transmitted over the PC5 link to the remote terminal using a NotificationMessageSidelink message.

[0098] At event 554, the remote terminal 502 starts a suspend data timer and suspends data transmissions to the intermediate relay terminal 102. In response to the suspend data notification message, the remote terminal 502 does not transmit data to the cell 120 over the relay communication link including the intermediate relay terminal 102. For the example for FIG. 5A, the remote terminal 502 does resume data transmissions to the intermediate relay terminal 102 until the resume data timer expires. In some situations, the intermediate relay terminal 102 sends a message invoking the remote terminal to perform relay selection. For example, where the intermediate relay terminal 102 is unable to reestablish the relay communication link, the intermediate relay terminal 102 sends a RLF notification or other message indicating that the intermediate relay terminal 102 is unable to facilitate a connection.

[0099] At event 516, the intermediate relay terminal 102 initiates relay selection. The intermediate relay terminal 102 receives and evaluates one or more discovery messages transmitted by candidate relay terminals and / or reference signals transmitted by cells. For the example of FIG. 5B, only a single discovery message 518 transmitted from a candidate relay terminal (last relay terminal) 118 is shown in the interest of clarity and brevity. However, multiple discovery messages and reference signals may be received and evaluated. At event 520, the intermediate relay terminal selects the last relay terminal 118 for providing the network-end communication link portion 115 to the network. For the example of FIG. 5B, the cell 120 is the same cell that facilitated the initial multi-hop relay communication link and the number of hops of the reestablished communication link is the same or less than the number of hops in the initial relay communication link. If the cell is different or the number hops is greater than the initial relay communication link, the intermediate relay terminal 102 sends failure notification to the remote terminal 502 invoking relay reselection.

[0100] At event 522, the intermediate relay terminal 102 establishes a PC5 link with the alternate last relay terminal 118. In accordance with known techniques, theTUTL 00411 PC-32- intermediate relay terminal 102 and alternate last relay terminal exchange messages to establish the PC5 link.

[0101] At transmission 524, the intermediate relay terminal 102 sends an RRC Reestablishment Request to the cell 120 via the last relay terminal 118. For the example, the last relay terminal 118 is in the RRC CONNECTED state with the cell 120. Accordingly, the RRC Reestablishment Request is forwarded within the SidelinkUEInformation message (SUI), an RRC message. If, however, the last relay terminal 118 is not yet RRC CONNECTED, the last relay terminal 118 transmits is own RRC Setup Request to the cell. Once the last relay terminal 118 is RRC CONNECTED, it can include the RRC Reestablishment Request of the intermediate relay terminal 102 to the cell within the SidelinkUEInformation message (SUI). If the cell is different or if the number hops is greater than the initial relay communication link, the intermediate relay terminal 102 sends a failure notification to the remote terminal 502 invoking relay reselection. The notification should be sent prior to timer expiry.

[0102] At transmission 528, the cell 120 sends an RRC Reestablishment message to the intermediate relay terminal 102 via the last relay terminal 118. At transmission 530, the intermediate relay terminal 102 sends an RRC Reestablishment Complete message to the cell 120. The intermediate relay terminal applies the parameters provided in the RRC Reestablishment message received at transmission 528 and transmits the RRC Reestablishment Complete message the via the last relay terminal 118 to the cell 120 to establish RRC with the cell 120.

[0103] At event 556, the suspend data timer expires at the remote terminal 502 and the remote terminal 502 resumes data transmission over the relay communication link through the intermediate relay terminal 102. At event 534 data communication is resumed between the remote terminal 502 and the network over the reestablished communication link including the intermediate relay terminal 102 and the last relay terminal 118.

[0104] FIG. 6 is a flow chart of an example of a method of performing an RRC connection initiation procedure. The method may be performed in a system such as the system 10 discussed herein. For the example, the method is performed by a terminal, such as the child terminal 12. The method may be performed using any of severalTUTL 00411 PC-33- techniques involving any combination of software, hardware, and firmware. For example, software code running on electronics including a processor, computer or other processor arrangement within the terminal may facilitate the generation, formatting, reception and transmission of signals and messages. One or more of the steps may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 6. In still further examples, additional steps may be added that are not explicitly described in connection with the example discussed with reference to FIG. 6.

[0105] At step 602, a terminal, such the child terminal 12, receives a discovery message from a relay terminal. The child terminal 12 is performing an RRC connection initiation procedure. Where the procedure is RRC Setup or RRC Reestablishment, the terminal receives discovery messages from candidate relay terminals during relay (re)selection. Where the RRC connection initiation procedure is RRC Resume, steps 602 and 604 are omitted.

[0106] At step 604, the terminal establishes a PC5 connection to the selected relay terminal. In accordance with 3GPP techniques, the child terminal 12 sends a Direct Communication Request to the selected relay terminal, receives a sidelink Direct Communication Accept message to establish the PC5 connection

[0107] At step 606, the child terminal receives system information including the standard timers that include at least the default RRC timers and may include the remote configured RRC timers. For example, a sidelink RRC message with SIB1 information including default RRC timer values is received from the relay terminal. The default RRC timers used for accessing a cell for the RRC connection initiation procedures to a cell are included in a UuMessageTransferSidelink message. The terminal 12 receives the UuMessageTransferSidelink message as a sidelink RRC signaling transmission over the PC5 interface, carrying system information including SIB1 and timer configuration parameters for downstream (child terminals). In some situations, the child terminal 12 may receive SIB 12 information including remote configured RRC timer values from the relay terminal. For example, the remote configured RRC timers used for accessing a cell for the RRC connection initiation procedures via one or more relay terminals are included in a UuMessageTransferSidelink message receives over the PC5 connection.TUTL 00411 PC-34-

[0108] At step 608, child terminal 12 calculates the extended RRC timer for the RRC connection initiation procedure being performed based, at least partially, on the hop count and the standard RRC timer for the RRC connection initiation procedure. The standard timer for the resume procedure may be the default timer value included in SIB1 or may be the remote configured RRC timer value included SIB12. For the example, the terminal 12 uses the remote configured RRC timer value if available to calculate the extended RRC timer value. Where the remote configured RRC timer value is not available, the terminal uses the default RRC timer value to calculate the extended RRC timer value. The RRC extended timer value is the product of the standard RRC timer value (either the default timer value or the remote configured timer value) and the hop count.

[0109] At step 610, the terminal starts the extended RRC timer.

[0110] A step 612, the terminal determines whether message is received or an event is detected that should stop the timer. If no message or event is detected, the method proceeds to step 614. Otherwise, the method continues at step 616.

[0111] At step 614, it is determined whether the extended RRC timer has expired. If the time has not expired, the method returns to step 612. Otherwise, the method continues at step 618 where it is determined that the RRC connection initiation procedure has failed. The terminal takes appropriate actions such performing relay reselection.

[0112] At step 616, it is determined whether a positive response message was received from the relay terminal. A positive response message includes an RRC Setup message for the RRC Setup procedure. For the RRC Reestablishment procedure, an RRC Reestablishment message or an RRC Setup message is a positive response message. For the RRC Resume procedure, an RRC Resume message is a positive response message. If a positive response message is received, the method proceeds to step 620. Otherwise, the method continues at step 622, where the timer is stopped before the method proceeds to step 618.

[0113] At step 620, the timer is stopped and the terminal completes the RRC connection initiation procedure. For example, the terminal sends an RRC SetupTUTL 00411 PC-35-Complete message, an RRC Reestablishment Complete message, or an RRC Resume Complete message depending on the positive response message that was received.

[0114] FIG. 7 is a flow chart of an example of method of establishing a relay communication link for a child terminal after an initial multi-hop relay communication link is no longer available (e.g., fails) where the relay terminals sends a suspend data notification to the child terminal to suspend data transmissions. The method may be performed in a system such as the system 100 discussed herein. For the example, the method is performed by a terminal that may be selected to perform the functions of an intermediate relay terminal, such as the intermediate relay terminal 102. The method may be performed using any of several techniques involving any combination of software, hardware, and firmware. For example, software code running on electronics including a processor, computer or other processor arrangement within the terminal may facilitate the generation, formatting, reception and transmission of signals and messages. One or more of the steps may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 7. In still further examples, additional steps may be added that are not explicitly described in connection with the example discussed with reference to FIG. 7.

[0115] For the example of FIG. 7, therefore, the intermediate relay terminal 102 sends a suspend data notification to a remote terminal 502 and performs a relay reselection procedure to establish a reestablished communication link 104 for the child terminal 502 after detecting a failure of the network-end portion 108 of the initial multihop relay communication link 110 between the remote terminal 502 and a network 112. For the example of FIG. 7, the initial multi-hop relay communication link 110 is between a remote terminal 502 and the network 112 where the remote terminal 502 is the child terminal and the intermediate relay terminal 102 is connected to an initial last relay terminal 504 through the PC5 link 128.

[0116] At step 702, the relay terminal facilitates and initial relay communication link between the network and the remote terminal. The initial relay communication link has a number, X, of hops.TUTL 00411 PC-36-

[0117] At step 704, the intermediate relay terminal 102 determines that the initial multi-hop relay communication link is no longer available. The determination may be based on detecting an RLF to the parent terminal of the intermediate relay terminal or receiving a failure notification, as well as other indications. Accordingly, it is determined that the network-end portion of the initial relay communication link 108 is unavailable.

[0118] At step 706, the intermediate relay terminal sends a suspend data notification to the remote terminal. In some circumstances, the suspend data notification indicates to the remote terminal that data transmission through the intermediate relay terminal should be suspended until another message is received from the intermediate relay terminal. In other circumstances, the suspend data notification includes a suspend data timer that is started by the remote terminal after receipt of the suspend data notification.

[0119] At step 708, the intermediate relay terminal 102 performs relay reselection to identify candidate alternate access nodes and to establish a communication link network-end portion. For the example, the intermediate relay terminal receives and evaluates signals from candidate access nodes which may include discovery signals from candidate relay terminals and reference signals from candidate cells. The intermediate relay terminal selects an access node establishes a PC5 link where the alternate access node is a terminal and establishes a Uu link where the alternate access node is a cell. The reestablished relay communication link using the selected access node has N hops.

[0120] At step 710, it is determined whether the reestablished relay communication link includes a different cell from the initial serving cell and whether the number of hops of the reestablished relay communication link is greater than the number of hops in the initial relay communication link. If either the number of hops, N, is greater than the number of hops, X, or if the cell is different from the initial cell, the method proceeds to step 712. Otherwise, the method continues at step 714.

[0121] At step 712, the intermediate relay terminal transmits a failure notification message to the remote terminal 504 to invoke relay reselection by the remote terminal.

[0122] If the suspend data notification included a suspend data timer, step 714 is omitted for the example. Otherwise, the intermediate relay terminal sends a resume data notification message to the remote terminal.TUTL 00411 PC-37-

[0123] At step 716, the intermediate relay terminal facilitates communication over the reestablished relay communication link between the remote terminal and the network.

[0124] To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. The described functionality may be implemented in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure. In accordance with various embodiments, a processor, device, component, circuit, structure, machine, module, etc. can be configured to perform one or more of the functions described herein. The term "configured to" or "configured for" as used herein with respect to a specified operation or function refers to processors, devices, components, circuits, electronics, and equipment that are physically constructed, programmed, instructed and / or arranged to perform the specified operation or function. Furthermore, the various illustrative logical blocks, modules, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), other electronics or combinations thereof. (ASIC), a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, electronics, and circuits can further include antennas and / or transceivers to communicate with various components within the network or within the device. A general-purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

[0125] When implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method orTUTL 00411 PC-38- algorithm disclosed herein can be implemented as software stored on a computer- readable medium. Computer readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0126] Therefore, the methods and apparatus of this invention may take the form, at least partially, of program logic or program code (i.e., instructions) embodied in tangible media, such as a machine-readable storage medium. When the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. The methods and apparatus of the present invention may also be embodied in the form of program code that is transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via any other form of transmission. When the program code is received and loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates analogously to specific logic circuits.

[0127] Additionally, memory or other storage, as well as communication components, may be employed in embodiments of the present disclosure. It will be appreciated that, for clarity purposes, the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without detracting from the present disclosure. For example, functionality illustrated to be performed by separate processing logic elements, or controllers, may be performed by the same processing logic element, or controller. Therefore, references to specificTUTL 00411 PC-39- functional units are only references to a suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

[0128] Clearly, other embodiments and modifications of this invention will occur readily to those of ordinary skill in the art in view of these teachings. The above description is illustrative and not restrictive. This invention is to be limited only by the following claims, which include all such embodiments and modifications when viewed in conjunction with the above specification and accompanying drawings. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.

Claims

TUTL 00411 PC-40-CLAIMS1 . A method comprising: obtaining a standard Radio Resource Control (RRC) timer value associated with an RRC connection initiation procedure; determining, at a child terminal, a number of hops of a relay communication path from the child terminal to a cell; applying a scaling factor to the standard RRC timer to determine an extended RRC timer value, the scaling factor based on the number of hops; transmitting, from the child terminal to the cell via the relay communication path, an RRC connection initiation message to initiate the RRC connection initiation procedure; initiating a timer for the extended RRC timer value; and determining the RRC connection initiation procedure has failed unless a positive RRC connection initiation response message is received from the cell before the timer has expired.

2. The method of claim 1 , wherein the RRC connection initiation procedure is an RRC Setup procedure, the RRC connection initiation message is an RRC Setup Request message, the standard RRC timer is a T300 timer, and the positive RRC connection initiation response message is an RRC Setup message.

3. The method of claim 1 , wherein the RRC connection initiation procedure is an RRC Reestablishment procedure, the RRC connection initiation message is an RRC Reestablishment Request message, the standard RRC timer is a T301 timer, and the positive RRC connection initiation response message is one of an RRC Reestablishment message or an RRC Setup Message.

4. The method of claim 1 , wherein the RRC connection initiation procedure is an RRC Resume procedure, the RRC connection initiation message is an RRC Resume Request message, the standard RRC timer is a T319 timer, and the positive RRC connection initiation response message is an RRC Resume message.TUTL 00411 PC-41-5. The method of claim 1 , further comprising: receiving the standard timer value in a System Information Broadcast SIB from a parent terminal in the relay communication path.

6. The method of claim 5, wherein receiving the standard timer value comprises receiving a default standard timer value in SIB1 from the parent terminal in the relay communication path, wherein the standard timer value is the default standard timer.

7. The method of claim 6, wherein the SIB1 is received in a UuMessageT ransferSidelink message.

8. The method of claim 5, wherein receiving the standard timer value comprises receiving a configured sidelink relay timer value in SIB12 from the parent terminal in the relay communication path, wherein the standard timer is the configured sidelink relay timer value.

9. The method of claim 8, further comprising: transmitting a RemotellEInformationSidelink message comprising an SIB request, wherein receiving the configured sidelink relay timer value in SIB12 comprises receiving the SIB12 in a ue-TimersAndConstantsRemotellE Information element (IE).

10. The method of claim 1 , further comprising: receiving, from a parent terminal of the relay communication path, a discovery signal comprising a hop number indicator, wherein determining the number of hops is based on the hop number indicator.11 . The method of claim 10, wherein the discovery signal comprises a scaling parameter, the scaling factor based on the scaling parameter.

12. The method of claim 1 , further comprising:TUTL 00411 PC-42- stopping the timer in response to receiving the positive RRC connection initiation response message from the cell.

13. A child terminal comprising: a receiver configured to receive a standard Radio Resource Control (RRC) timer value associated with an RRC connection initiation procedure; a controller configured to determine, at the child terminal, a number of hops of a relay communication path from the child terminal to a cell and to apply a scaling factor to the standard RRC timer to determine an extended RRC timer value, the scaling factor based on the number of hops; and a transmitter configured to transmit, from the child terminal to the cell via the relay communication path, an RRC connection initiation message to initiate the RRC connection initiation procedure, the controller further configured to initiate a timer for the extended RRC timer value and determine the RRC connection initiation procedure has failed unless a positive RRC connection initiation response message is received from the cell before the timer has expired.

14. A method comprising: facilitating, by an intermediate relay terminal, an initial multi-hop relay communication link between a child terminal and a network, the initial multi-hop relay communication link comprising a first PC5 link between the child terminal and the intermediate relay terminal and an initial multi-hop network-end communication link portion between the intermediate relay terminal and the network; in response to detecting the initial multi-hop network-end communication link portion is no longer available, transmitting a suspend data notification message to the child terminal instructing the child terminal to suspend data transmission over the initial multi-hop relay communication link; in response to detecting the initial multi-hop network-end communication link portion is no longer available, performing a reestablishment process to establish a reestablished communication link between the child terminal and the network;TUTL 00411 PC-43- facilitating, by the intermediate relay terminal, data communication between the child terminal and a network through the reestablished communication link.

15. The method of claim 14, further comprising: transmitting a resume data notification to the child terminal instructing the child terminal to resume data transmission.

16. The method of claim 15, wherein the suspend data notification comprises a suspend data timer to invoke the child terminal to suspend data transmission through the intermediate relay terminal for the suspend data timer period.

17. The method of claim 14, wherein facilitating data communication between the child terminal and the network through the reestablished communication link is in response to determining a serving cell of initial multi-hop relay communication link and the reestablished communication link is the same cell and determining that a reestablished hop number of the reestablished communication link is less than or equal to the initial hop number of the initial multi-hop relay communication link.

18. The method of claim 17, further comprising: sending a failure notification message to the child terminal in response to determining an initial serving cell of the initial multi-hop relay communication link and a reestablished link serving cell of the reestablished communication link are different cells.

19. The method of claim 17, further comprising: sending a failure notification message to the child terminal in response to determining reestablished hop number is greater than the initial hop number.

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