PATENT DOCUMENT

Publication Number: US-11895548-B2
Application Number: US-202017247017-A
Country: US
Kind Code: B2

Title: Link management for a connected user equipment

Abstract:
A base station may be configured to perform operations related to link management for a remote user equipment (UE). The operations comprising, transmitting configuration information to the remote UE and receiving information corresponding to a serving link associated with the remote UE. The operations further comprising determining that the serving link associated with the remote UE is to be switched from a first communication link to a second communication link. The operations further comprising, transmitting a message to the remote UE indicating that the serving link associated with the remote UE is to be switched from the first communication link to the second communication link. The operations further comprising, transmitting a message to a relay UE. The message is configured to trigger the relay UE to perform an operation corresponding to the serving link associated with the remote UE.

Claims:
What is claimed: 
     
       1. A method, comprising:
 at a base station:
 transmitting configuration information to a remote user equipment (UE); 
 receiving information corresponding to a serving link associated with the remote UE; 
 determining that the serving link associated with the remote UE is to be switched from a Uu link to a relay link; 
 transmitting a radio resource control (RRC) reconfiguration message to the remote UE on the Uu link indicating that the serving link associated with the remote UE is to be switched from the Uu link to the relay link; 
 transmitting a message to a relay UE, wherein the message is configured to trigger the relay UE to establish the relay link with the remote UE; 
 
 receiving a RRC reconfiguration complete message from the remote UE via the relay link; and
 receiving a message from the relay UE, wherein the message indicates that the relay UE has detected that the relay link to the remote UE is broken. 
 
 
     
     
       2. The method of  claim 1 , wherein the message indicating that the serving link associated with the remote UE is to be switched from the Uu link to the relay link is configured to trigger the remote UE to establish the relay link with the relay UE. 
     
     
       3. The method of  claim 1 , wherein the information corresponding to the serving link associated with the remote UE is received directly from the remote UE over a Uu link. 
     
     
       4. The method of  claim 1 , wherein the message to the remote UE indicating that the serving link associated with the remote UE is to be switched from the Uu link to the relay link is transmitted directly to the remote UE over the Uu link. 
     
     
       5. The method of  claim 1 , wherein determining that the serving link associated with the remote UE is to be switched from the Uu link to the relay link is based on initiating a handover of the relay UE to a further base station. 
     
     
       6. The method of  claim 1 , further comprising:
 receiving a message from the relay UE, the message indicating that the relay UE cannot accept the remote UE. 
 
     
     
       7. The method of  claim 1 , wherein the message from the relay UE indicating that the relay UE has detected that the relay link to the remote UE is broken is based on measurement data collected by the relay UE on the relay link, the method further comprising receiving the measurement data from the UE. 
     
     
       8. The method of  claim 7 , further comprising using the measurement data to switch to a new serving link associated with the remote UE. 
     
     
       9. A base station, comprising:
 a communication interface; and 
 a processor configured to perform operations, the operations comprising:
 transmitting configuration information to a remote user equipment (UE); 
 receiving information corresponding to a serving link associated with the remote UE; 
 determining that the serving link associated with the remote UE is to be switched from a Uu link to a relay link; 
 transmitting a radio resource control (RRC) reconfiguration message to the remote UE on the Uu link indicating that the serving link associated with the remote UE is to be switched from the Uu link to the relay link; 
 transmitting a message to a relay UE, wherein the message is configured to trigger the relay UE to establish the relay link with the remote UE; 
 receiving a RRC reconfiguration complete message from the remote UE via the relay link; and 
 receiving a message from the relay UE, wherein the message indicates that the relay UE has detected that the relay link to the remote UE is broken. 
 
 
     
     
       10. The base station of  claim 9 , wherein the message indicating that the serving link associated with the remote UE is to be switched from the Uu link to the relay link is configured to trigger the remote UE to establish a relay link with the relay UE. 
     
     
       11. The base station of  claim 9 , wherein the information corresponding to the serving link associated with the remote UE is received directly from the remote UE over a Uu link or indirectly from the remote UE via a relay link. 
     
     
       12. The base station of  claim 9 , wherein the message to the remote UE indicating that the serving link associated with the remote UE is to be switched from the Uu link to the relay link is transmitted directly to the remote UE over the Uu link. 
     
     
       13. The base station of  claim 9 , wherein determining that the serving link associated with the remote UE is to be switched from the Uu link to the relay link is based on initiating a handover of the relay UE to a further base station. 
     
     
       14. The base station of  claim 9 , wherein the message from the relay UE indicating that the relay UE has detected that the relay link to the remote UE is broken is based on measurement data collected by the relay UE on the relay link, and the operations further comprising receiving the measurement data from the UE. 
     
     
       15. The base station of  claim 14 , the operations further comprising using the measurement data to switch to a new serving link associated with the remote UE. 
     
     
       16. A method, comprising:
 at a remote user equipment (UE) configured to communicate with a network using a first communication link:
 receiving configuration information from the network; 
 transmitting to the network one or more of i) measurement data corresponding to the first communication link or a second communication link or ii) preference information; 
 receiving radio resource control (RRC) reconfiguration message from the network on a Uu link, the RRC reconfiguration message comprising an indication that a communication link of the remote UE is to be switched from the Uu link to a relay link; 
 
 establishing the relay link to the relay UE; and 
 transmitting a RRC reconfiguration complete message to the network via the relay link. 
 
     
     
       17. The method of  claim 16 , wherein the first communication link comprises a first relay link with a first UE and the second communication link comprises a second relay link with a second UE.

Description:
BACKGROUND 
     A user equipment (UE) may establish a connection to at least one of multiple networks or types of networks. In some scenarios, the UE may communicate with the network using a direct communication link to a base station of the corresponding network. In other scenarios, the UE may communicate with the network using a UE to network relay. For example, the UE may establish a direct communication link with a further UE that is camped on a base station of the corresponding network. In this type of arrangement, data and information sent to the network by the UE may initially be transmitted to the further UE and then relayed to the base station by the further UE on behalf of the UE. For downlink communications intended for the UE, data and information may initially be sent to the further UE and then relayed to the UE by the further UE on behalf of the network. 
     The network may manage how the UE is to communicate with the network. That is, the network may determine whether the UE is to be configured to communicate directly with a base station or is to be configured to utilize a UE to network relay. The network may make this determination using information received directly or indirectly from any of a variety of sources including, but not limited to, the UE and the further UE. 
     SUMMARY 
     According to an exemplary embodiment a method is performed at a base station. The method comprising, transmitting configuration information to a remote user equipment (UE) and receiving information corresponding to a serving link associated with the remote UE. The method further comprising determining that the serving link associated with the remote UE is to be switched from a first communication link to a second communication link. The method further comprising, transmitting a message to the remote UE indicating that the serving link associated with the remote UE is to be switched from the first communication link to the second communication link. The method further comprising, transmitting a message to a relay UE. The message is configured to trigger the relay UE to perform an operation corresponding to the serving link associated with the remote UE. 
     According to another exemplary embodiment, a base station includes a communication interface and a processor configured to perform operations. The operations comprising transmitting configuration information to a remote user equipment (UE) and receiving information corresponding to a serving link associated with the remote UE. The operation further comprising, determining that the serving link associated with the remote UE is to be switched from a first communication link to a second communication link. The operations further comprising, transmitting a message to the remote UE indicating that the serving link associated with the remote UE is to be switched from the first communication link to the second communication link. The operations further comprising, transmitting a message to a relay UE. The message is configured to trigger the relay UE to perform an operation corresponding to the serving link associated with the remote UE. 
     According to a further exemplary embodiment, a method is performed by a remote user equipment (UE) configured to communicate with a network using a first communication link. The method comprising, receiving configuration information from the network and transmitting to the network one or more of i) measurement data corresponding to the first communication link or a second communication link or ii) preference information. The method further comprising, receiving from the network an indication to switch from the first communication link to the second communication link. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows an exemplary network arrangement according to various exemplary embodiments. 
         FIG.  2    shows an exemplary UE according to various exemplary embodiments. 
         FIG.  3    shows a method for link management for a connected UE according to various exemplary embodiments. 
         FIGS.  4   a - 4   c    each illustrate an exemplary scenario to related link management. 
         FIG.  5    shows a signaling diagram for switching the serving link of the remote UE from a relay link to a Uu link according to various exemplary embodiments. 
         FIG.  6    shows a signaling diagram for switching the serving link of the remote UE from a Uu link to a relay link according to various exemplary embodiments. 
         FIG.  7    shows a signaling diagram for switching the serving link of the remote UE from a first relay link to a second relay link according to various exemplary embodiments. 
         FIG.  8    shows a signaling diagram for switching the serving link of the remote UE based on information corresponding to the relay UE&#39;s Uu link according to various exemplary embodiments. 
         FIG.  9    shows a signaling diagram for unsuccessfully switching the serving link of the remote UE from a Uu link to a relay link according to various exemplary embodiments. 
         FIG.  10    shows a signaling diagram for unsuccessfully switching the serving link of the remote UE from a Uu link to a relay link according to various exemplary embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The exemplary embodiments may be further understood with reference to the following description and the related appended drawings, wherein like elements are provided with the same reference numerals. The exemplary embodiments describe devices, systems and methods to implement various link management mechanisms. As will be described below, link management generally refers to establishing and maintaining a communication link that is to be utilized to communicate, directly or indirectly, with a network. 
     The exemplary embodiments are described with regard to the UE. However, the use of a UE is merely provided for illustrative purposes. The exemplary embodiments may be utilized with any electronic component that is configured with the hardware, software, and/or firmware to exchange information (e.g., control information) and/or data with the network. Therefore, the UE as described herein is used to represent any suitable electronic device. 
     To perform the full scope of functionalities normally available to the UE via a network connection, the UE may directly or indirectly communicate with a base station of the corresponding network. The UE may directly communicate with a currently camped base station. The UE may indirectly communicate with the base station using a UE to network relay. For example, the UE may be configured with a direct communication link to a further UE while the further UE is camped on the base station. In this type of arrangement, the further UE may serve as a relay for the UE. Thus, data and information sent to the network by the UE may initially be transmitted to the further UE and then relayed to the base station by the further UE on behalf of the UE. For downlink communications intended for the UE, data and information may initially be sent to the further UE and then relayed to the UE by the further UE on behalf of the network. 
     The exemplary embodiments may characterize the UE to network relay as a layer 2 (L2) relay. From the protocol stack perspective, the L2 relay may include one or more layers between the UE and the further UE, one or more layers between the UE and the base station, one or more layers between the UE and the core network, one or more layers between the further UE and the base station and one or more layers between the base station and the core network. However, those skilled in the art would understand that the exemplary embodiments are not limited to a L2 relay and may also apply to a layer 3 (L3) relay or any other appropriate type of relay. Accordingly, throughout this description the term “UE to network relay” may represent any appropriate configuration in which an electronic component (e.g., the further UE) operates as a relay between a UE and a base station. 
     The exemplary embodiments relate to link management. Throughout this description, the term “link management” generally refers to establishing and maintaining a communication link that is to be utilized by the UE to communicate, directly or indirectly, with a network. Link management may be controlled by the network, however, the term link management may encompass various operations performed at the UE, at one or more further UEs, one or more base stations, the radio access network (RAN) and the core network. Throughout this description reference to the network performing an operation may refer to an operation performed at a base station, at a RAN, at a core network, at a network function, at a network services backbone, a network server, any other type of network component or combination thereof. 
     Link management may include the network determining whether the UE is to communicate directly with a base station or indirectly with the base station using a UE to network relay. To differentiate between UEs, reference will be made to a “remote UE” and a “relay UE.” The term “remote UE” may be used to identify a UE that is to operate as a remote endpoint from the base station. The remote UE may connect directly to the base station or indirectly communicate with the base station using a UE to network relay. Throughout this description, the terms UE and remote UE may be used interchangeably. The term “relay UE” may be used to identify a UE that may serve as a relay for the remote UE. The term relay UE is not intended to indicate that the relay UE is actively serving as a relay. Instead, the term relay UE indicates that the UE has the capability of operating as a relay for a remote UE. Further, the relay UE may also be configured as a remote UE simultaneously. Throughout this description, the terms UE, further UE and relay UE may be used interchangeably. However, any reference to a remote UE and a relay UE is merely for illustrative purposes, different networks may refer to similar concepts by a different name. 
     The exemplary embodiments describe various link management mechanisms for a remote UE in a radio resource control (RRC) connected state. Those skilled in the art will understand that when the UE is in the RRC connected state, the UE may exchange information and/or data with the connected network. The exchange of information and/or data may enable the UE to perform functionalities normally available via the network connection. Some exemplary scenarios described below may include the remote UE being configured with a UE to network relay and then switching to a direct communication link with the network, the remote UE being configured with a direct communications link with the network and then switching to a UE to network relay and the remote UE camping on a communication link with a first relay UE and switching to camping on a communication link of a second relay UE. As mentioned above, link management may include the network determining whether the remote UE is to communicate directly with a base station or indirectly using a UE to network relay. This determination may be made using information received from various sources including, but not limited to, the remote UE and one or more relay UEs. 
       FIG.  1    shows an exemplary network arrangement  100  according to various exemplary embodiments. The exemplary network arrangement  100  includes UEs  110 ,  112 . Those skilled in the art will understand that the UEs  110 ,  112  may be any type of electronic component that is configured to communicate via a network, e.g., a mobile phone, a tablet computer, a smartphone, a phablet, an embedded device, a wearable, an Internet of Things (IoT) device, a massive machine-type communication (mMTC) device, etc. It should also be understood that an actual network arrangement may include any number of UEs being used by any number of users. Thus, the example of two UEs  110 ,  112  is merely provided for illustrative purposes. 
     The UEs  110 ,  112  may communicate directly with one or more networks. In the example of the network configuration  100 , the networks with which the UEs  110 ,  112  may wirelessly communicate are a 5G New Radio (NR) radio access network (5G NR-RAN)  120 , a LTE radio access network (LTE-RAN)  122  and a wireless local access network (WLAN)  124 . However, the UEs  110 ,  112  may also communicate with other types of networks and the UEs  110 ,  112  may also communicate with networks over a wired connection. Therefore, the UEs  110 ,  112  may include a 5G NR chipset to communicate with the 5G NR-RAN  120 , an LTE chipset to communicate with the LTE-RAN  122  and an ISM chipset to communicate with the WLAN  124 . 
     The 5G NR-RAN  120  and the LTE-RAN  122  may be portions of cellular networks that may be deployed by cellular providers (e.g., Verizon, AT&amp;T, Sprint, T-Mobile, etc.). These networks  120 ,  122  may include, for example, base stations (Node Bs, eNodeBs, HeNBs, eNBS, gNBs, gNodeBs, macrocells, microcells, small cells, femtocells, etc.) that are configured to send and receive traffic from UEs that are equipped with the appropriate cellular chip set. The WLAN  124  may include any type of wireless local area network (WiFi, Hot Spot, IEEE 802.11x networks, etc.). 
     The base stations (e.g., the gNB  120 A, the eNB  122 A) may include one or more communication interfaces to exchange data and/or information with camped UEs, the corresponding RAN, the cellular core network  130 , the internet  140 , etc. Further, the base stations may include a processor configured to perform various operations. For example, the processor of the base station may be configured to perform operations related to link management. However, reference to a processor is merely for illustrative purposes. The operations of the base station may also be represented as a separate incorporated component of the base station or may be a modular component coupled to the base station, e.g., an integrated circuit with or without firmware. For example, the integrated circuit may include input circuitry to receive signals and processing circuitry to process the signals and other information. In addition, in some base stations, the functionality of the processor is split among two or more processors such as a baseband processor and an applications processor. The exemplary embodiments may be implemented in any of these or other configurations of a base station. 
     Those skilled in the art will understand that any association procedure may be performed for the UEs  110 ,  112  to connect to the 5G NR-RAN  120  and the LTE-RAN  122 . For example, as discussed above, the 5G NR-RAN  120  and the LTE-RAN  122  may be associated with a particular cellular provider where the UEs  110 ,  112  and/or the user thereof has a contract and credential information (e.g., stored on a SIM card). Upon detecting the presence of the 5G NR-RAN  120 , the UEs  110 ,  112  may transmit the corresponding credential information to associate with the 5G NR-RAN  120 . More specifically, the UEs  110 ,  112  may associate with a specific base station (e.g., the gNB  120 A of the 5G NR-RAN  120 , the eNB  122 A of the LTE-RAN  122 ). 
     The UEs  110 ,  112  may also communicate indirectly with the one or more networks using a UE to network relay. For example, the UE  110  may be a remote UE and the UE  112  may be a relay UE. In this example, the UE  112  may camp on the gNB  120 A of the 5G NR-RAN  120  and the UE  110  may camp on the UE  112 . Uplink communications from the UE  110  may initially be transmitted over a communication link to the UE  112 . Subsequently, the UE  112  may relay the communication to the gNB  120 A on behalf of the UE  110 . Downlink communication from the gNB  120 A to the UE  110  may initially be sent to the UE  112 . Subsequently, the UE  112  may relay the communication to the UE  110  on behalf of the gNB  120 A. Those skilled in the art would understand that in this example the gNB  120 A, the 5G NR-RAN  120  and/or the core network  130  may manage the communication link between the UE  110  and the UE  112 . 
     Throughout this description, the UE  110  may be referenced as a remote UE and the UE  112  may be referenced as a relay UE. However, this is only for illustrative purposes and is not intended to limit the exemplary embodiments in any way. 
     In addition to the networks  120 ,  122  and  124  the network arrangement  100  also includes a cellular core network  130 , the Internet  140 , an IP Multimedia Subsystem (IMS)  150 , and a network services backbone  160 . The cellular core network  130  may be considered to be the interconnected set of components that manages the operation and traffic of the cellular network. The cellular core network  130  also manages the traffic that flows between the cellular network and the Internet  140 . The IMS  150  may be generally described as an architecture for delivering multimedia services to the UE  110  using the IP protocol. The IMS  150  may communicate with the cellular core network  130  and the Internet  140  to provide the multimedia services to the UE  110 . The network services backbone  160  is in communication either directly or indirectly with the Internet  140  and the cellular core network  130 . The network services backbone  160  may be generally described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a suite of services that may be used to extend the functionalities of the UE  110  in communication with the various networks. 
       FIG.  2    shows an exemplary UE  110  according to various exemplary embodiments. The UE  110  will be described with regard to the network arrangement  100  of  FIG.  1   . The UE  110  may include a processor  205 , a memory arrangement  210 , a display device  215 , an input/output (I/O) device  220 , a transceiver  225  and other components  230 . The other components  230  may include, for example, a SIM card, an audio input device, an audio output device, a power supply, a data acquisition device, ports to electrically connect the UE  110  to other electronic devices, etc. Those skilled in the art will understand that the UE  110  may represent any electronic component that is capable of operating as a remote UE and/or a relay UE. 
     The processor  205  may be configured to execute a plurality of engines of the UE  110 . For example, the engines may include a link management engine  235 . The link management engine  235  may perform various operations related to link management including, but not limited to, receiving configuration information from the network regarding link management, collecting measurement data and reporting information to the network that may be utilized for link management purposes. 
     The above referenced engines each being an application (e.g., a program) executed by the processor  205  is only exemplary. The functionality associated with the engines may also be represented as a separate incorporated component of the UE  110  or may be a modular component coupled to the UE  110 , e.g., an integrated circuit with or without firmware. For example, the integrated circuit may include input circuitry to receive signals and processing circuitry to process the signals and other information. The engines may also be embodied as one application or separate applications. In addition, in some UEs, the functionality described for the processor  205  is split among two or more processors such as a baseband processor and an applications processor. The exemplary embodiments may be implemented in any of these or other configurations of a UE. 
     The memory arrangement  210  may be a hardware component configured to store data related to operations performed by the UE  110 . The display device  215  may be a hardware component configured to show data to a user while the I/O device  220  may be a hardware component that enables the user to enter inputs. The display device  215  and the I/O device  220  may be separate components or integrated together such as a touchscreen. The transceiver  225  may be a hardware component configured to establish a connection with the 5G NR-RAN  120 , the LTE-RAN  122 , the WLAN  124 , the UE  112 , etc. Accordingly, the transceiver  225  may operate on a variety of different frequencies or channels (e.g., set of consecutive frequencies). 
     The UE  110  may be configured to be in one of a plurality of different operating states. One operating state may be characterized as RRC connected state and another operating state may be characterized as RRC idle state. RRC refers to the radio resource control (RRC) protocols. Those skilled in the art will understand that when the UE  110  is in an RRC connected state, the UE  110  may exchange information and/or data with the connected network. The exchange of information and/or data may enable the UE  110  to perform functionalities available via the network connection. Thus, the UE  110  may be in the RRC connected state when the UE  110  is camped on a base station or when the UE  110  is camped on a relay UE. 
     Further, those skilled in the art will understand that when the UE  110  is connected to the network and in RRC idle state the UE  110  is not exchanging data with the network and radio resources are not being assigned to the UE  110  within the network. However, when the UE  110  is operating in RRC idle state the UE  110  may listen for transmissions from the network. 
     When deployed within the network, the UE  110  may transition between operating states. For example, the UE  110  may be camped on a base station of a corresponding network and experience a connection issue. Subsequently, the UE  110  may transition from the RRC connected state to the RRC idle state. At this point, the UE  110  is still camped on the base station but is now in the RRC idle state. When the UE  110  is in the RRC idle state, the UE  110  may not be able to exchange data with the network. To exchange data with the network, the UE  110  may transition from the RRC idle state to the RRC connected state. Specifically, while in RRC idle state the UE  110  may listen for information such as but not limited to, primary synchronization signals (PSS) and secondary synchronization signals (SSS), Master Information Block (MIB), broadcast messages, System Information Block (SIB), paging notifications etc. In response, the UE  110  may issue a request to the network that indicates that the UE  110  wants to be moved to the RRC connected state. A successful transition from the RRC idle state to the RRC connected state may include the exchange of messages between the UE  110  and a base station (directly or indirectly via a UE to network relay). In the RRC connected state, a network context may be established between the network and the UE  110 . Thus, the UE  110  may be assigned radio resources and the UE  110  may be able to exchange data with the network. The scenario described above is only intended to provide a general example of the UE  110  transitioning between the RRC connected state and the RRC idle state. Those skilled in the art would understand that the UE  110  may operate in a different RRC state (e.g., inactive state) and may transition between RRC states while the UE  110  is camped on the further UE  112 . 
     The exemplary embodiments described below relate to the UE  110  operating in the RRC connected state. Throughout this description, the term “connected UE” may refer to a UE operating in the RRC connected state. 
       FIG.  3    shows a method  300  for link management for a connected UE according to various exemplary embodiments. The method  300  will be described with regard to the network arrangement  100  of  FIG.  1    and the UE  110  of  FIG.  2   . 
     In  305 , a remote UE  110  receives network configuration information. For example, the UE  110  may initially be camped on the gNB  120 A of the 5G NR-RAN  120 . When camped, the UE  110  may receive configuration information related to link management. This configuration information may be received in a variety of different ways including, but not limited to, a system information block (SIB), an RRC procedure, control information, etc. In some embodiments, the UE  110  may receive this configuration information from the network via a relay UE  112 . However, the exemplary embodiments are not limited to the remote UE  110  receiving configuration information in any particular manner. 
     The network configuration information may indicate to the remote UE  110  how the remote UE  110  is to provide the network with information related to link management. For example, the configuration information may indicate to the remote UE  110  that the remote UE  110  is to collect measurement data corresponding to a serving base station, a non-serving base station, a serving relay UE and a non-serving relay UE. The measurement data may be per base station, per relay UE or per frequency band. This measurement data may be subsequently provided to the network as part of link management for the remote UE  110 . 
     The configuration information may also indicate when the remote UE  110  is to provide the network with the measurement data. For instance, the configuration information may indicate to the remote UE  110  that a measurement report is to be provided to the network periodically in accordance with a schedule or a timer. The configuration information may also indicate that the measurement report is to be provided based on a predetermined condition. For example, the remote UE  110  may be configured to collect measurement data corresponding to a serving link (e.g., a base station or a relay UE) and measurement data corresponding to non-serving entities (e.g., base stations, relay UEs, etc.). If the measurement data satisfies a predetermined threshold, the remote UE  110  may be triggered to provide the measurement report to the network. In some embodiments, the remote UE  110  may be triggered to provide a measurement report including measurement data already collected and in other embodiments the remote UE  110  may be configured to collect additional measurement data for the measurement report that is to be provided. As will be described below, the measurement data may be utilized by the network to determine whether the remote UE  110  should switch to a different serving link. 
     In  310 , the remote UE  110  transmits a measurement report to the network. For example, the UE  110  may collect measurement data in accordance with the configuration information received in  305 . Subsequently, the UE  110  may provide the gNB  120 A with a measurement report. If the UE  110  is camped on the gNB  120 A, the UE  110  may provide the measurement report directly to the gNB  120 A. If the UE  110  is camped on the UE  112 , the UE  110  may provide the measurement report indirectly to the gNB  120 A via the UE  112 . A person of ordinary skill in the art would understand the contents and format of the measurement report and how it is provided to the gNB  120 A. 
     Link management may be applicable to a variety of different scenarios. As will be described below with regard to  FIG.  4   a   - 4   c,  the remote UE  110  may be configured to provide a measurement report in a variety of different scenarios. The network may determine that the serving link of the remote UE  110  is to be switched to a different serving link based on the measurement report. 
       FIGS.  4   a - 4   c    each illustrate an exemplary scenario related link management.  FIGS.  4   a - 4   c    will be described with regard to the network arrangement  100  of  FIG.  1    and the UE  110  of  FIG.  2   . 
       FIG.  4   a    shows a scenario  400  that includes the UE  110 , the UE  112  and the gNB  120 A of the 5G NR-RAN  120 . In the scenario  400 , the UE  110  is camped on the gNB  120 A and operating in the RRC connected state. Thus, the UE  110  is communicating with the gNB  120 A directly and is not utilizing a relay to network UE. Those skilled in the art would understand that the interface between the 5G NR-RAN  120  and the UE  110  may be referred to as a Uu interface. Throughout this description, a direct communication link between a UE and a base station of the 5G NR-RAN  120  may be referred to as a “Uu link.” Thus, in the scenario  400 , the communication link  402  between the UE  110  and the gNB  120 A is an example of a Uu link. 
     In the scenario  400 , the UE  112  is also camped on the gNB  120 A. There is no direct communication link between the UE  110  and the UE  112 . During operation, the UE  110  may be configured to collect measurement data corresponding to the UE  112  and provide it to the network. The network may utilize this information to determine that the UE  110  should switch from the Uu link to a relay link with the UE  112 . 
       FIG.  4   b    shows a scenario  410  that also includes the UE  110 , the UE  112  and the gNB  120 A of the 5G NR-RAN  120 . In the scenario  410 , the UE  110  is in the RRC connected state and configured with a UE to network relay. Thus, the UE  112  is camped on the gNB  120 A and the UE  110  is connected to the UE  112  via the relay link  412 . During operation, uplink communications from the UE  110  may initially be transmitted to the UE  112  via the relay link  412 . Subsequently, the UE  112  may relay the uplink communications to the gNB  120 A via the Uu link  414  on behalf of the UE  110 . For downlink communications intended for the UE  110 , the gNB  120 A may initially transmit the communication to the UE  112  via the Uu link  414  of the UE  112 . Subsequently, the UE  112  may relay the downlink communications to the UE  110  via the relay link  412  on behalf of the gNB  120 A. 
     In the scenario  410 , the UE  110  is not camped on the gNB  120 A. Thus, there is no direct communication link (e.g., Uu link) between the UE  110  and the gNB  120 A. During operation, the UE  110  may be configured to collect measurement data corresponding to the gNB  120 A (and/or any other non-serving base stations) and provide the measurement data to the network. The network may utilize this information to determine that the UE  110  should switch from the relay link  412  to a Uu link with the gNB  120 A. For example, based on the measurement data, the network may cause the UE  110  to switch from the scenario  410  of  FIG.  4   b    to the scenario  400  of  FIG.  4   a    or vice versa. 
     In the scenario  410 , the UE  110  may be within the coverage area of the gNB  120 A. However, since the UE  110  is communicating with the network via the UE  112 , the UE  110  may be located outside of the coverage area of the gNB  120 A. Thus, the scenario  410  may enable the UE  110  to communicate with the gNB  120 A while the UE  110  is outside of the coverage area of the gNB  120 A. 
       FIG.  4   c    shows a scenario  420  that includes the UE  110 , the UE  112 , a UE  422  and the gNB  120 A of the 5G NR-RAN  120 . In the scenario  420 , both the UE  112  and the UE  422  are camped on the gNB  120 A. The UE  110  is configured with a UE to network relay using the UE  112 . Thus, there is no direct communication link between the UE  110  and the gNB  120 A. During operation, the UE  110  may be configured to collect measurement data corresponding to the UE  422  and provide the measurement data to the network. The network may utilize this information to determine that the UE  110  should switch from the relay link  424  with the UE  112  to the relay link  426  with the UE  422 . 
     In  FIG.  4   c    the relay link  424  and the relay link  426  are both shown. This is not intended to demonstrate that both the relay link  424  and the relay link  426  are being configured at the same time. Instead, the relay link  424  and the relay link  426  are both shown to demonstrate that there may be scenarios in which the network causes a remote UE to switch from a first relay UE to a second relay UE. In an actual scenario, there may be multiple remote UEs and multiple relay UEs. Thus, the use of a single remote UE (e.g., UE  110 ) and two relay UEs (e.g., UE  112  and UE  422 ) is only provided for illustrative purposes. 
     As mentioned above the remote UE may provide the network with the measurement data in response to a predetermined condition. Examples of various predetermined conditions are described below with regard to  FIGS.  4   a   - 4   c.    
     Initially, consider the scenario  400  of  FIG.  4   a   . During operation, if the UE  110  determines that the quality of the connection via the Uu link  402  is less than a predetermined threshold or that the quality of the non-serving relay link associated with the UE  112  is greater than a predetermined threshold, the UE  110  may collect measurement data corresponding to the UE  112 . The UE  110  may then provide the measurement data to the gNB  120 A. The UE  110  may also collect measurement data corresponding to any other potential relay UE&#39;s within proximity to the UE  110 . Subsequently, the network may switch the UE  110  from the Uu link  402  to a relay link with the UE  112  based on the measurement data. 
     Continuing with the scenario  400  of  FIG.  4   a   , if the UE  110  determines that the difference in the quality of the non-serving relay link associated with the UE  112  and the quality of the Uu link  402  is greater than a predetermined threshold, the UE  110  may be triggered to provide measurement data to the network for the purposes of link management. Similarly, if the quality of the non-serving relay link is greater than a predetermined threshold and the quality of the Uu link  402  is less than a predetermined threshold the UE  110  may be triggered to provide measurement data to the network for the purposes of link management. The above described examples are merely provided for illustrative purposes and the exemplary embodiments may apply to providing measurement data to the network based on any appropriate condition. 
     Consider the scenario  410  of  FIG.  4   b   , if the UE  110  determines that a quality of the relay link  412  is less than a predetermined threshold or the quality associated with a non-serving base station (gNB  120 A) is greater than a predetermined threshold, the UE  110  may collect measurement data corresponding to the gNB  120 A. The UE  110  may then provide the measurement data to the gNB  120 A via the relay link  412 . Subsequently, the network may switch the UE  110  from the relay link  412  to a Uu link with the gNB  120 A based on the measurement data. The above described examples are merely provided for illustrative purposes and the exemplary embodiments may apply to providing measurement data to the network based on any appropriate condition. 
     Consider the scenario  420  of  FIG.  4   c   , if the UE  110  determines that the quality of the serving relay link  424  is less than a predetermined threshold, the quality of the non-serving relay link  426  is a above a predetermined threshold or the quality of a non-serving base station (gnB  120 A) is greater than a predetermined threshold, the UE  110  may collect measurement data corresponding to these links. The UE  110  may then provide the measurement data to the gNB  120 A via the serving relay link  424 . Subsequently, the network may switch the UE  110  from the relay link  424  to a Uu link with the gNB  120 A or the relay link  426  based on the measurement data. 
     Continuing with the scenario  420  of  FIG.  4   c   , if the UE  110  determines that the difference in the quality of the non-serving relay link  426  and the quality of the serving relay link  424  is greater than a predetermined threshold, the UE  110  may be triggered to provide measurement data to the network for the purposes of link management. Similarly, if the quality of the non-serving link is greater than a predetermined threshold and the quality of a serving link is less than a predetermined threshold, the UE  110  may be triggered to provide measurement data to the network for the purposes of link management. The above described examples are merely provided for illustrative purposes and the exemplary embodiments may apply to providing measurement data to the network based on any appropriate condition. 
     Returning to the method  300 , in  315 , the network determines that the remote UE is to switch its currently camped serving link. For example, based on a measurement report provided by the remote UE, the network may determine that a different serving link would provide the remote UE with better service. Switching the serving link of the remote UE may include switching from a Uu link to a relay link, switching from a relay link to a Uu link or switching from a first relay link to a second relay link. A person of ordinary skill in the art would understand that link management may also include configuring the remote UE with a different serving base station. Subsequently, the network may initiate signaling to switch the serving link for the remote UE. 
     In the example provided above, the determination made by the network is performed on the basis of the measurement report provided by the remote UE. However, the exemplary embodiments are not limited to the network making this determination on any particular basis. For example, the remote UE may be configured to provide the network with an indication of the remote UE&#39;s serving link preference. This indication may be provided with the measurement report or without the measurement report and cause the network to switch the remote UE&#39;s serving link. The remote UE may provide this indication of preference if the remote UE identifies that the quality of service (QoS) associated with the serving link has degraded, fallen below a threshold value or come within a particular range of a threshold value. In this type of scenario, the indication may identify that the remote UE desires to switch from the serving link to a different link due to the serving link&#39;s degradation in quality. The remote UE may also provide this indication of preference in scenarios that cause the remote UE to experience a power drain. For example, if the remote UE is configured with a Uu link in a poor coverage area, the remote UE may perform operations using high power and thus, experience a power drain. In this type of scenario, the indication may identify that the remote UE desires to switch from the serving link to a different link due to the power cost at the remote UE. The above examples are only provided for illustrative purposes and the exemplary embodiments may relate to the remote UE providing the network with an indication of the remote UE&#39;s serving link preference for any appropriate reason. 
     The determination made in  315  is not limited to explicit information provided by the remote UE. For example, the network may detect the quality of the remote UE&#39;s serving link on the network side. Thus, the network may make link management decisions for the remote UE based on measurements performed on the network side. In another example, the network may receive information from one or more relay UEs within the proximity of the remote UE. The relay UEs may provide information of radio or transmission quality related to a non-serving relay link available to the remote UE. The relay UEs may also provide information related to their respective Uu links. Thus, the network may utilize information received from the relay UEs to make link management decisions for the remote UE. 
     In  320 , the network configures the remote UE with a different serving link. Various exemplary signaling diagrams related to switching the serving link of the remote UE are provided below in  FIGS.  5 - 10   . 
       FIG.  5    shows a signaling diagram  500  for switching the serving link of the remote UE from a relay link to a Uu link according to various exemplary embodiments. The signaling diagram  500  is described with regard to the network arrangement  100  of  FIG.  1   , the UE  110  of  FIG.  2    and the method  300  of  FIG.  3   . 
     The signaling diagram  500  includes the UE  110  as the remote UE, the UE  112  as the relay UE and the gNB  120 A of the 5G NR-RAN  120 . Initially, the UE  110  is in RRC connected mode and camped on the UE  112  while the UE  112  is in RRC connected mode and camped on the gNB  120 A. An example of this arrangement is shown in the scenario  410  of  FIG.  4     b.    
     In  505 , the UE  110  collects measurement data. In this example, the measurement data may correspond to the serving relay link with the UE  112  and the non-serving gNB  120 A. However, in other arrangements, the measurement data may correspond to other non-serving relay UEs and non-serving base stations. 
     As mentioned above, the UE  110  may perform measurements based on network configuration information. If the measurement data satisfies a predetermined threshold, the UE  110  may be triggered to provide a measurement report to the network. This allows the network to provide the UE  110  with a serving link that may provide better service than the currently camped serving link. 
     In  510 , the UE  110  transmits a measurement report to the gNB  120 A over the relay link with the UE  112 . In this example, the UE  110  is currently camped on the UE  112  and thus, uplink communications to the gNB  120 A are initially transmitted to the UE  112 . The measurement report may include a variety of different types of information including, but not limited to, a relayID corresponding to the serving relay link, a relayID corresponding to a non-serving relay UE, a base station ID corresponding to a non-serving base station, explicit measurement data, etc. 
     In  515 , the UE  112  relays the measurement report received from the UE  110  to the gNB  120 A on behalf of the UE  110 . In some embodiments, the UE  112  may also provide information corresponding to the UE  110  that the network may utilize for link management of the UE  110 . This information may be included with the information relayed on behalf of the UE  110  or may be included in a separate message. 
     In  520 , the network determines that the serving link for the UE  110  is to be switched from the relay link with the UE  112  to a Uu link with the gNB  120 A. This determination may be performed on the basis of the measurement report. For example, the measurement report may indicate that the quality of the serving relay link for the UE  110  is inadequate, the UE  110  no longer prefers to be connected to the UE  112 , the non-serving gNB  120 A may provide better service, etc. However, as mentioned above, the network may also make this determination based on measurements performed on the network side or measurements performed by the UE  112 . 
     In  525 , the gNB  120 A transmits an RRC reconfiguration message to the UE  110 . Since, the UE  110  is still configured with the relay link to the UE  112 , the RRC reconfiguration message is initially sent to the UE  112 . In  530 , the UE  112  relays the RRC reconfiguration message to the UE  110  on behalf of the gNB  120 A. The RRC reconfiguration message indicates to the UE  110  that the UE  110  is to establish an RRC connection with the gNB  120 A. 
     In  535 , the UE  110  transmits an RRC reconfiguration complete message to the gNB  120 A directly using a Uu link. This indicates to the network that the UE  110  has switched from the relay link of the UE  112  to the Uu link of the gNB  120 A. In  540 , the gNB  120  transmits a message to the UE  112  indicating to the UE  112  that the UE  112  can release the relay link to the UE  110 . 
     The UE  110  is now in the RRC connected mode and camped on the gNB  120 A. Thus, the arrangement changes from the scenario  410  of  FIG.  4   b    to the scenario  400  of  FIG.  4     a.    
       FIG.  6    shows a signaling diagram  600  for switching the serving link of the remote UE from a Uu link to a relay link according to various exemplary embodiments. The signaling diagram  600  is described with regard to the network arrangement  100  of  FIG.  1   , the UE  110  of  FIG.  2    and the method  300  of  FIG.  3   . 
     The signaling diagram  600  includes the UE  110  as the remote UE, the UE  112  as the relay UE and the gNB  120 A of the 5G NR-RAN  120 . Initially, the UE  110  is in RRC connected mode and camped on the gNB  120 A while the UE  112  is also in RRC connected mode and camped on the gNB  120 A. An example of this arrangement is shown in the scenario  400  of the  FIG.  4     a.    
     In  605 , the UE  110  collects measurement data. In this example, the measurement data may correspond to the serving Uu link with the gNB  120 A and the non-serving UE  112 . However, in other arrangements, the measurement data may correspond to other non-serving relay UEs and non-serving base stations. 
     In  610 , the UE  110  transmits a measurement report to the gNB  120 A. Since the UE  110  is camped on the gNB  120 A, the measurement report is transmitted directly to the gNB  120 A over the Uu link. The measurement report may include a variety of different types of information including, but not limited to, a relayID corresponding to a non-serving relay UE, a base station ID corresponding to a non-serving base station, explicit measurement data, etc. 
     In  615 , the network determines that the serving link for the UE  110  is to be switched from the Uu link with the gNB  120 A to a relay link with the UE  112 . This determination may be performed on the basis of the measurement report. For example, the measurement report may indicate that the quality of the serving Uu link for the UE  110  is inadequate, the UE  110  no longer prefers to be connected to the gNB  120 A, the non-serving UE  112  may provide better service, etc. However, as mentioned above, the network may also make this determination based on measurements performed on the network side or measurements performed by the UE  112 . 
     In  620 , the gNB  120 A transmits a message to the UE  112  including configuration information for the UE  110 . This message may enable the UE  112  to serve as a relay for the UE  110 . In  625 , the UE  112  transmits a message to the gNB  120 A indicating that the configuration is complete and the UE  112  is ready to connect to the UE  110 . 
     In  630 , the gNB  120 A sends an RRC reconfiguration message to the UE  110  over the Uu link. Since the UE  110  is still camped on the gNB  120 A, the RRC reconfiguration message is provided directly to the UE  110 . 
     In  635 , the UE  110  and the UE  112  participate in a signaling exchange to establish a serving relay link. In  640 , the UE  110  transmits an RRC reconfiguration complete message to the gNB  120 A. Since the UE  110  is now configured with a serving relay link, the RRC reconfiguration complete message is transmitted to the gNB  120 A over the relay link. In  645 , the UE  112  relays the RRC reconfiguration complete message to the gNB  120 A on behalf of the UE  110 . 
     In some embodiments, the UE  112  may activate the relay link and serve as the relay for the UE  110  based on receiving an acknowledgement (ACK) from the gNB  120 A in response to the RRC reconfiguration complete message. Alternatively, the UE  112  may activate the relay link on any explicit or implicit indication received from the gNB  120 A or any explicit or implicit indication received from the UE  110 . 
     The UE  110  is now in the RRC connected mode and camped on the UE  112 . Thus, the arrangement changes from the scenario  400  of  FIG.  4   a    to the scenario  410  of  FIG.  4     b.    
       FIG.  7    shows a signaling diagram  700  for switching the serving link of the remote UE from a first relay link to a second relay link according to various exemplary embodiments. The signaling diagram  700  is described with regard to the network arrangement  100  of  FIG.  1   , the UE  110  of  FIG.  2    and the method  300  of  FIG.  3   . 
     The signaling diagram  700  includes the UE  110  as the remote UE, the UE  112  as the first relay UE, the UE  422  as the second relay UE and the gNB  120 A of the 5G NR-RAN  120 . Initially, the UE  110  is in RRC connected mode and camped on the UE  112  while both the UEs  112 ,  422  are also in RRC connected mode and camped on the gNB  120 A. An example of this arrangement is shown in the scenario  420  of the  FIG.  4   c    where the relay link  424  is the serving relay link and the relay link  426  is a non-serving relay link. 
     In  705 , the UE  110  collects measurement data. In this example, the measurement data may correspond to the serving relay link with the UE  112 , the non-serving relay link with the UE  422  and the non-serving gNB  120 A. However, in other arrangements, the measurement data may correspond to other non-serving relay UEs and non-serving base stations. 
     In  710 , the UE  110  transmits a measurement report to the gNB  120 A over the relay link with the UE  112 . In this example, the UE  110  is currently camped on the UE  112  and thus, uplink communications to the gNB  120 A are initially transmitted to the UE  112 . The measurement report may include a variety of different types of information including, but not limited to, a relayID corresponding to the serving relay link, a relayID corresponding to a non-serving relay UE, a base station ID corresponding to a non-serving base station, explicit measurement data, etc. 
     In  715 , the UE  112  relays the measurement report received from the UE  110  to the gNB  120 A on behalf of the UE  110 . 
     In  720 , the network determines that the serving link for the UE  110  is to be switched from the relay link with the UE  112  to a relay link with the UE  422 . This determination may be performed on the basis of the measurement report. For example, the measurement report may indicate that the quality of the serving relay link is inadequate, the UE  110  no longer prefers to be connected to the UE  112 , the non-serving UE  422  may provide better service, etc. However, as mentioned above, the network may also make this determination based on measurements performed on the network side or measurements performed by the UE  112 . 
     In  725 , the gNB  120 A transmits a message to the UE  422  including configuration information for the UE  110 . This message may enable the UE  422  to serve as a relay for the UE  110 . In  730 , the UE  422  transmits a message to the gNB  120 A indicating that configuration is complete and the UE  422  is ready to connect to the UE  110 . 
     In  735 , the gNB  120 A transmits an RRC reconfiguration message to the UE  110 . Since, the UE  110  is still configured with the relay link to the UE  112 , the RRC reconfiguration message is initially sent to the UE  112 . In  740 , the UE  112  relays the RRC reconfiguration message to the UE  110  on behalf of the gNB  120 A. The RRC reconfiguration message indicates to the UE  110  that the UE  110  is to establish an RRC connection with the UE  422 . 
     In  745 , the UE  110  and the UE  422  participate in a signaling exchange to establish a serving relay link. In  750 , the UE  110  transmits an RRC reconfiguration complete message to the gNB  120 A. Since the UE  110  is now configured with a serving relay link to the UE  422 , the RRC reconfiguration complete message is transmitted to the gNB  120 A over the relay link to the UE  422 . In  755 , the UE  422  relays the RRC reconfiguration complete message to the gNB  120 A on behalf of the UE  110 . 
     In  760 , the gNB  120  transmits a message to the UE  112  indicating to the UE  112  that the UE  112  can release the relay link to the UE  110 . The UE  110  is now in the RRC connected mode and camped on the UE  7422 . With regard to the scenario  420  of  FIG.  4 C , the arrangement changes from the serving link being the relay link  424  to the serving link being the relay link  426 . 
     As mentioned above, the network may also perform link management for the remote UE based on information received from the relay UE. For example, when the network configures the remote UE with a UE to network relay, the network may provide the relay UE with configuration information related to link management for the remote UE. 
     In some embodiments, the relay UE may be configured to measure the relay link of the remote UE. For example, the relay UE may be configured to collect measurement data corresponding to the radio quality level or transmission quality level of the relay link. The relay UE may collect this measurement data by measuring the relay link in the direction of the remote UE or may receive the measurement data from the remote UE in a remote UE to relay UE report. Unlike the measurement reports mentioned above, the remote UE to relay UE report may be generated for the relay UE. To provide another example, the relay UE may calculate the block error rate (BLER) in L2. 
     The relay UE may be configured to provide this measurement data periodically in accordance with a schedule or a timer. The relay UE may also be configured to provide this measurement data in response to a predetermined condition. For example, the relay UE may be configured to indicate to the network that a connection issue has occurred with the relay link if the collected measurement data falls below a threshold value or satisfies a predetermined condition. Other exemplary predetermined conditions may include, but are not limited to, the relay UE detecting that the relay link with the remote UE is broken, the relay UE detecting that the relay link with the remote UE does not satisfy QoS requirements, the relay UE detecting that a power drain or thermal situation is occurring at the relay UE, the relay UE detecting that performance of the relay UE is degrading due to the relay link, the relay UE detecting congestion of the relay link, the relay UE determining that the relay link is to be switched off/on and the relay UE determining that the relay UE is to offload all currently camped remote UEs. 
     If the relay UE is triggered to provide the information associated with the remote UE to the network, the network may utilize this information to switch the serving link of the remote UE. For example, signaling diagrams  500 - 700  were described with regard to the network switching the link of the remote UE based on measurement data collected by the remote UE and provided by the remote UE to the network. However, the network may make the same link switching determinations described in the signaling diagrams  500 - 700  using the information collected by the relay UE and provided by the relay UE to the network. 
       FIG.  8    shows a signaling diagram  800  for switching the serving link of the remote UE based on information corresponding to the relay UE&#39;s Uu link according to various exemplary embodiments. The signaling diagram  800  is described with regard to the network arrangement  100  of  FIG.  1   , the UE  110  of  FIG.  2    and the method  300  of  FIG.  3   . 
     The signaling diagram  800  includes the UE  110  as the remote UE, the UE  112  as the relay UE and the gNB  120 A of the 5G NR-RAN  120 . Initially, the UE  110  is in RRC connected mode and camped on the UE  112  while the UE  112  is in RRC connected mode and camped on the gNB  120 A. An example of this arrangement is shown in the scenario  410  of the  FIG.  4     b.    
     During operation, the network may determine that the serving relay link for the UE  110  is to be changed based on identifying a predetermined condition associated with the Uu link of the UE  112 . For example, if the network determines that the quality of Uu link is degrading, the network may want to handoff the UE  112  to a different base station. Prior to the handoff, the network may switch the serving link of the remote UE. 
     In  805 , the UE  112  collects measurement data. In this example, the measurement data may correspond to the Uu link of the UE  112 . 
     In  810 , the UE  112  transmits a measurement report to the gNB  120 A. In  815 , the network determines determine that a handoff of the UE  112  is to be performed to a different base station. Prior to performing the handoff, the network may switch the serving link of the UE  110 . 
     In  820 , the gNB  120 A transmits an RRC reconfiguration message to the UE  110 . Since the UE  110  is configured with a serving relay link to the UE  112 , the RRC reconfiguration message is initially sent to the UE  112 . In  825 , the UE  112  relays the RRC reconfiguration message to the UE  110  on behalf of the gNB  120 A. 
     The RRC reconfiguration message may instruct the UE  110  that the UE  110  is to switch its serving link from the relay link with the UE  112  to a different link. This may include switching the UE  110  from the relay link with the UE  112  to a Uu link with the gNB  120 A, switching the UE  110  from the relay link with the UE  112  to a relay link with a further relay UE or switching the UE  110  from the relay link with the UE  112  to a Uu link with a further base station. In this example, the RRC reconfiguration information instructs the UE  110  that the UE  110  is to switch its serving link to a Uu link with the gNB  120 A. 
     In  830 , the UE  110  may transmit an RRC reconfiguration complete message to the gNB  120 A. 
     In  835 , the gNB  120 A transits a handover command to the UE  112 . Subsequently, the UE  112  may establish a connection to the network based on the handover command. 
     During operation, for any of a variety of different reasons, the link switching procedure may fail. An example of the link switching procedure failing at the remote UE is shown below in the signaling diagram  900  of  FIG.  9    and an example of the link switching procedure failing at the relay UE is shown below in the signaling diagram  1000  of  FIG.  10   . 
       FIG.  9    shows a signaling diagram  900  for unsuccessfully switching the serving link of the remote UE from a Uu link to a relay link according to various exemplary embodiments. The signaling diagram  900  is described with regard to the network arrangement  100  of  FIG.  1   , the UE  110  of  FIG.  2   , the method  300  of  FIG.  3    and the signaling diagram  600  of  FIG.  6   . 
     The signaling diagram  900  includes the UE  110  as the remote UE, the UE  112  as the relay UE and the gNB  120 A of the 5G NR-RAN  120 . Initially, the UE  110  is in RRC connected mode and camped on the gNB  120 A while the UE  112  is also in RRC connected mode and camped on the gNB  120 A. An example of this arrangement is shown in the scenario  400  of the  FIG.  4   a   . While this example is described with regard to the above referenced scenario, those skilled in the art would understand that the concepts described for the signaling diagram  900  may be applicable to any scenario in which a link switching procedure fails at the remote UE. 
     In  905 , the UE  110  collects measurement data. This is substantially similar to  605  of the signaling diagram  600  of  FIG.  6   . 
     In  910 , the UE  110  transmits a measurement report to the gNB  120 A. Since the UE  110  is camped on the gNB  120 A, the measurement report is transmitted directly to the gNB  120 A over the Uu link. In  915 , the network determines that the serving link for the UE  110  is to be switched from the Uu link with the gNB  120 A to a relay link with the UE  112 .  910 - 915  are substantially similar to  610 - 615  of the signaling diagram  600  of  FIG.  6   . 
     In  920 , the gNB  120 A transmits a message to the UE  112  including configuration information for the UE  110 . This message may enable the UE  112  to serve as a relay for the UE  110 . In  925 , the UE  112  transmits a message to the gNB  120 A indicating that configuration is complete and the UE  112  is ready to connect to the UE  110 .  920 - 925  are substantially similar to of the signaling diagram  600  of  FIG.  6   . 
     In  930 , the gNB  120 A sends an RRC reconfiguration message to the UE  110  over the Uu link. Since the UE  110  is still camped on the gNB  120 A, the RRC reconfiguration message is provided directly to the UE  110 . 
     In  935 , the UE  110  attempts to establish a relay link with the UE  112 . However, for any of a variety of different reasons, the attempt fails. 
     In  940 , the UE  110  is triggered to perform link reselection. This may include tuning the transceiver  225  to various frequency bands, collecting measurement data and initiating a connection establishment procedure with a base station or a relay UE. 
     In  945 , the gNB  120 A experiences a timeout because the gNB  120 A does not receive a RRC reconfiguration complete message from the UE  110 . In  950 , the gNB  120 A sends an indication to the UE  112  that the UE  112  may release the configuration of relay link with the UE  110 . In  955 , the UE  112  may send a release complete message to the gNB  120 A indicating that the relay link with the UE  110  has been released. 
       FIG.  10    shows a signaling diagram  1000  for unsuccessfully switching the serving link of the remote UE from a Uu link to a relay link according to various exemplary embodiments. The signaling diagram  1000  is described with regard to the network arrangement  100  of  FIG.  1   , the UE  110  of  FIG.  2   , the method  300  of  FIG.  3    and the signaling diagram  600  of  FIG.  6   . 
     The signaling diagram  1000  includes the UE  110  as the remote UE, the UE  112  as the relay UE and the gNB  120 A of the 5G NR-RAN  120 . Initially, the UE  110  is in RRC connected mode and camped on the gNB  120 A while the UE  112  is also in RRC connected mode and camped on the gNB  120 A. An example of this arrangement is shown in the scenario  400  of the  FIG.  4   a   . While this example is described with regard to the above referenced scenario, those skilled in the art would understand that the concepts described for the signaling diagram  1000  may be applicable to any scenario in which a link switching procedure fails at the relay UE. 
     In  1005 , the UE  110  collects measurement data. This is substantially similar to  605  of the signaling diagram  600  of  FIG.  6   . 
     In  1010 , the UE  110  transmits a measurement report to the gNB  120 A. Since the UE  110  is camped on the gNB  120 A, the measurement report is transmitted directly to the gNB  120 A over the Uu link. In  1015 , the network determines that the serving link for the UE  110  is to be switched from the Uu link with the gNB  120 A to a relay link with the UE  112 .  1010 - 1015  are substantially similar to  610 - 615  of the signaling diagram  600  of  FIG.  6   . 
     In  1020 , the gNB  120 A transmits a message to the UE  112  including configuration information for the UE  110 . 
     In  1025 , the UE  112  determines that the UE  112  cannot accept the UE  110 . For example, the relay link of the UE  112  may lack the capacity to adequately serve the UE  110 . However, this is only provided for illustrative purposes, and the relay UE may determine that it cannot accept a remote UE for any appropriate reason. 
     In  1030 , the UE  112  transmits a relay link configuration failure message to the gNB  120 A. Subsequently, the network may determine how to manage the serving link for the UE  110 . For example, the network may decide to keep the UE  110  at the currently camped Uu link, to handoff the UE  110  to a different base station or to switch the Uu link to a relay link of a different relay UE. 
     Those skilled in the art will understand that the above-described exemplary embodiments may be implemented in any suitable software or hardware configuration or combination thereof. An exemplary hardware platform for implementing the exemplary embodiments may include, for example, an Intel x86 based platform with compatible operating system, a Windows OS, a Mac platform and MAC OS, a mobile device having an operating system such as iOS, Android, etc. In a further example, the exemplary embodiments of the above described method may be embodied as a program containing lines of code stored on a non-transitory computer readable storage medium that, when compiled, may be executed on a processor or microprocessor. 
     It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     It will be apparent to those skilled in the art that various modifications may be made in the present disclosure, without departing from the spirit or the scope of the disclosure. Thus, it is intended that the present disclosure cover modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalent

Metadata:
Filing Date: 20201124
Publication Date: 20240206
Grant Date: 20240206
Priority Date: 20191128
Inventors: XU, FANGLI
ZHANG, DAWEI
HU, HAIJING
XING, LONGDA
SHIKARI, MURTAZA A.
Gurumoorthy, Sethuraman
KODALI, Sree Ram
NIMMALA, SRINIVASAN
LOVLEKAR, SRIRANG A.
CHEN, YUQIN
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W36/302", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W76/23", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W36/0085", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/0058", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0094", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W84/047", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W88/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W76/23", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/302", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/302", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 73642564