Type information at the time of HO related to voice fallback handover

Abstract

A system and method are disclosed for radio link failure reporting with an indication indicating whether the last successfully completed handover was for voice fallback purposes. In one embodiment, a method implemented by a user equipment (UE) includes receiving configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication indicating that the handover is for voice fallback purposes. The method further includes connecting to a cell served by the second network node, declaring a radio link failure in the cell served by the second network node, and storing information related to the radio link failure in a report in response to the indication, the information including the indication that the last successfully completed handover was for voice fallback purposes.

Description

[Technical Field]

[0001] Related Applications This application claims the benefit of Provisional Patent Application No. 63 / 396,393, filed August 9, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] TECHNICAL FIELD The present disclosure relates to cellular communication systems, and more particularly to reporting information related to radio link failures after successful or unsuccessful handovers. [Background technology]

[0003] Voice fallback from New Radio (NR) to Long Term Evolution (LTE) In the 3rd Generation Partnership Project (3GPP), New Radio (NR) to Long Term Evolution (LTE) voice fallback is used to transfer user equipment (UE) from NR to LTE during a call establishment procedure. The voice fallback allows UEs to utilize all NR capabilities except for voice options in locations where the NR network is not optimized for voice services. To support various deployment scenarios for obtaining Internet Protocol (IP) Multimedia Subsystem (IMS) voice services, UEs and Next Generation Radio Access Networks (NG-RANs) may support mechanisms to direct or redirect UEs from NG-RANs to either an Enhanced Universal Terrestrial Radio Access (E-UTRA) network connected to a 5th Generation Core (5GC) (Radio Access Technology (RAT) fallback) or an Evolved Packet System (EPS) (E-UTRAN fallback) connected to an Evolved Packet Core (EPC) system. During the UE registration procedure, the serving access and mobility management function (AMF) informs the UE whether an IMS voice over Packet Switch (PS) session is supported. If a request to establish a Quality of Service (QoS) flow for IMS voice reaches the NG-RAN, the NG-RAN responds by indicating a rejection of the establishment request, and the NG-RAN may trigger one of the following procedures depending on the UE capabilities, N26 availability, network configuration, and radio conditions: Redirection to EPS, Handover procedure to EPS, Redirection to E-UTRA connected to 5GC, or Handover to E-UTRA connected to 5GC.

[0004] Further details can be found in 3GPP Technical Specification (TS) 23.501 (see, for example, V17.4.0).

[0005] Figure 1 illustrates the EPS fallback procedure for IMS voice. A detailed description of Figure 1 can be found in section 4.13.6.1 of 3GPP TS23.502 (see, for example, V17.4.0).

[0006] Self-Organizing Networks (SON) in 3GPP Self-organizing networks (SON) are automated technologies designed to make planning, configuration, management, optimization, and repair of mobile radio access networks easier and faster. SON functions and behaviors are defined and specified in accepted mobile industry recommendations produced by organizations such as 3GPP and Next Generation Mobile Networks (NGMN).

[0007] In 3GPP, processes within the SON area are classified into self-configuration and self-optimization processes. The self-configuration process is a process in which a newly deployed node is configured by an automatic installation procedure to obtain the necessary basic configuration for system operation. This process works in a pre-operational state. The pre-operational state is understood as the state from when an evolved Node B (eNB) is powered up and has backbone connectivity until its radio frequency (RF) transmitter is switched on.

[0008] Figure 2 shows the branching of the self-configuration / self-optimization functions (from 3GPP TS36.300 Figure 22.1-1). As shown in Figure 2, the functions that are handled in the pre-operational state are: Basic setup, and Initial wireless settings are covered by the self-configuration process.

[0009] The self-optimization process is defined as the process in which UE and access node measurements and performance measurements are used to auto-tune the network. This process works in the operational state, which is understood as the state in which the RF interface is also switched on. As illustrated in Figure 2, the functions handled in the operational state are: Optimization / Adaptation are covered by the self-optimization process.

[0010] LTE specifies support for self-configuration and self-optimization as described in 3GPP TS36.300 section 22.2, including features such as dynamic configuration, automatic neighbor relations (ANR), mobility load balancing, mobility robustness optimization (MRO), and random access channel (RACH) optimization and support for energy savings.

[0011] NR similarly specifies support for self-configuration and self-optimization, starting with self-configuration features such as dynamic configuration, automatic neighbor relations (ANR) in Rel-15, as described in 3GPP TS38.300 Section 15. NR Rel-16 specifies more SON features, including self-optimization features such as mobility robustness optimization (MRO).

[0012] Mobility Robustness Optimization (MRO) in 3GPP Seamless handover is a key feature of 3GPP technology. A successful handover ensures that a UE can move around in the coverage areas of different cells without causing too many interruptions in data transmission. However, there will be scenarios in which the network fails to handover the UE to the "correct" neighboring cell in time; in such scenarios, the UE will declare a Radio Link Failure (RLF) or Handover Failure (HOF).

[0013] During HOF and RLF, the UE may take autonomous actions, i.e., select a cell and initiate a re-establishment procedure, to ensure that the UE returns as quickly as possible and thus may be reachable again. Because RLF is declared by the UE only when it realizes that there is no reliable communication channel (radio link) available between itself and the network, RLF will cause a poor user experience. Also, re-establishing a connection requires signaling (random access procedure, radio resource control (RRC) re-establishment request, RRC re-establishment, RRC re-establishment complete, RRC reconfiguration, and RRC re-configuration complete) with the newly selected cell until the UE can exchange data with the network again, adding some latency.

[0014] According to the 3GPP specifications (see 3GPP TS36.331), the possible causes for RLF can be one of the following: 1) Expiration of the radio link monitoring related timer T310, 2) expiry of the measurement report related timer T312 (no handover command is received from the network within the duration of this timer, despite sending a measurement report when T310 was running); 3) When the maximum number of Radio Link Control (RLC) retransmissions is reached, 4) Upon receiving a random access problem indication from the Medium Access Control (MAC) entity.

[0015] Since RLF leads to re-establishments that degrade performance and user experience, it is for the network to understand the reason for RLF and try to optimize mobility-related parameters (e.g., trigger conditions for measurement reports) to avoid later RLF. Before the standardization of MRO-related report handling in the network, only the UE was aware of some information related to what the radio quality was at the time of the RLF, what the actual reason for declaring RLF was, etc. In order for the network to identify the reason for RLF, the network needs more information from both the UE and also from neighboring base stations.

[0016] As part of the MRO solution for LTE, the RLF reporting procedure was introduced in the RRC specification in the Rel-9 RAN2 work. It influenced the RRC specification (3GPP TS36.331) in that it specified that the UE should log relevant information at the moment of RLF and later report it to the target cell to which the UE has successfully connected (e.g., after re-establishment). It also influenced the gNodeB-to-gNodeB interface, i.e., the X2AP specification (3GPP TS36.423), since an eNodeB receiving an RLF report can forward it to the failed eNodeB.

[0017] For RLF reports generated by the UE, the content of the RLF report has been extended with more details in subsequent releases. The measurements included in a measurement report based on the latest LTE RRC specification (see TS23.501 V17.4.0) are: 1) Measurement quantities (reference signal received power (RSRP), reference signal received quality (RSRQ)) of the last serving cell (primary cell (PCell)). 2) Measurements of neighboring cells at different frequencies for different RATs (E-UTRA, Universal Terrestrial Radio Access (UTRA), Global System for Mobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN), and Code Division Multiple Access (CDMA) 2000 (CDMA2000)). 3) Measurement quantities related to wireless local area network (WLAN) access points (APs) (Received Strength of Signal Indicator (RSSI)). 4) Measurements related to Bluetooth beacons (RSSI). 5) Location information (including location coordinates and speed), if available 6) If available, the globally unique identity of the last serving cell; otherwise, the physical cell identity (PCI) and carrier frequency of the last serving cell. 7) Tracking area code of the PCell. 8) The time elapsed since the last receipt of a "Handover Command" message. 9) The Cell Radio Network Temporary Identifier (C-RNTI) used in the previous serving cell. 10) Whether a Data Radio Bearer (DRB) with a QoS Class Identifier (QCI) value of 1 has been established in the UE.

[0018] After the RLF is declared, the RLF report is logged and included in VarRLF-Report, and once the UE selects a cell and the re-establishment is successful, the UE includes an indication that the UE has an RLF report available in the RRC Re-establishment Complete message to make the target cell aware of its availability. Then, upon receiving a UEInformationRequest message with flag "rlf-ReportReq-r9", the UE includes the RLF report (stored in the UE variable VarRLF-Report, as described above) in the UEInformationResponse message and sends the UEInformationResponse message to the network.

[0019] Based on the RLF report from the UE and its knowledge of the cell to which the UE has reestablished itself, the original source cell can infer whether the RLF was caused by a coverage hole or by handover-related parameter settings. If the RLF is deemed to be due to handover-related parameter settings, the original serving cell can further classify the handover-related failure as a premature handover, a late handover, or a handover to the wrong cell class. These handover failure classes are briefly described below. 1) Whether the handover failure occurred due to a "too late handover" case a. The original serving cell may classify a handover failure as a "too late handover" when the original serving cell fails to send a handover command to the UE associated with the handover towards a particular target cell, and if the UE re-establishes itself in this target cell after an RLF. b. An exemplary corrective action from the original serving cell could be to initiate the handover procedure towards the target cell a little earlier by decreasing the CIO (Cell Individual Offset) towards this target cell, which controls when the IE sends the event-triggered measurement report that leads to making the handover decision. 2) Whether the handover failure occurred due to a "premature handover" case a. The original serving cell may classify a handover failure as a "premature handover" when the original serving cell successfully sends a handover command to the UE involved in the handover, but the UE fails to perform random access towards this target cell. b. An exemplary corrective action from the original serving cell could be to initiate the handover procedure towards the target cell a little later by increasing the CIO (Cell Individual Offset) towards this target cell, which controls when the IE sends the event-triggered measurement report that leads to making the handover decision. 3) Whether the handover failure occurred due to a "handover to wrong cell" case a. The original serving cell may classify a handover failure as a "handover to a wrong cell" when the original serving cell intends to perform a handover for this UE towards a particular target cell, but the UE declares RLF and re-establishes itself in a third cell. b. Corrective action from the original serving cell could be to initiate a measurement reporting procedure leading to a slightly later handover towards the target cell by decreasing the CIO (Cell Individual Offset) towards the target cell, or via the UE initiating a handover towards the re-established cell slightly earlier by increasing the CIO towards the re-established cell. Summary of the Invention

[0020] A system and method are disclosed for enhancing a radio link failure report with an indication indicating whether the last successfully completed handover was for voice fallback purposes. In one embodiment, a method implemented by a user equipment (UE) includes receiving configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication indicating that the handover is for voice fallback purposes. The method further includes, in response to receiving the configuration, connecting to a cell served by the second network node. The method further includes declaring a radio link failure in the cell served by the second network node, and, in response to declaring the radio link failure in the cell served by the second network node and the indication indicating that the handover is for voice fallback purposes, storing information related to the radio link failure in a report, the information including an indication that the last completed handover for the first network node to the second network node was for voice fallback purposes. Based on this information, including the above indication, the network is enabled to identify whether the last completed handover was a voice fallback handover or not, and thus, if such a handover is classified as a premature handover or a handover to a wrong cell, the network node can optimize voice fallback handover related mobility parameters.

[0021] In one embodiment, the first radio access technology is New Radio (NR) and the second radio access technology is Long Term Evolution (LTE). In one embodiment, the indication is MobilityFromNR with voice fallback indication. In one embodiment, the report is a radio link failure report, and storing information related to the radio link failure includes storing the information in a VarRLF-Report variable.

[0022] In one embodiment, the report is a radio link failure report.

[0023] In one embodiment, the method further includes selecting a cell, reconnecting to the cell, and sending a report to a network node associated with the cell.

[0024] Corresponding embodiments of a UE are also disclosed. In one embodiment, the UE is configured to receive configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes. The UE is further configured to connect to a cell served by the second network node in response to receiving the configuration. The UE is further configured to declare a radio link failure in the cell served by the second network node, and to store information related to the radio link failure in a report in response to declaring the radio link failure in the cell served by the second network node and the indication indicating that the handover is for voice fallback purposes, the information including an indication that the last completed handover for the first network node to the second network node was for voice fallback purposes.

[0025] In one embodiment, a UE comprises a communications interface and processing circuitry associated with the communications interface. The processing circuitry is configured to cause the UE to receive configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes. The processing circuitry is further configured to cause the UE to connect to a cell served by the second network node in response to receiving the configuration. The processing circuitry is further configured to cause the UE to declare a radio link failure in the cell served by the second network node and, in response to declaring the radio link failure in the cell served by the second network node and the indication indicating that the handover is for voice fallback purposes, store information related to the radio link failure in a report, the information including an indication that the last completed handover for the first network node to the second network node was for voice fallback purposes.

[0026] Also disclosed are embodiments of a method implemented by a network node. In one embodiment, the method implemented by the network node includes receiving a radio link failure report from a UE, the radio link failure report including an indication that a last completed handover for the UE from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology was for voice fallback purposes. The method further includes performing one or more actions based on the radio link failure report.

[0027] In one embodiment, the one or more actions include sending a radio link failure report to another network node.

[0028] In one embodiment, the one or more actions include sending a radio link failure report to the first network node.

[0029] In one embodiment, the first radio access technology is NR and the second radio access technology is LTE.

[0030] In one embodiment, the network node is a base station.

[0031] Corresponding embodiments of a network node are also disclosed. In one embodiment, the network node is configured to receive a radio link failure report from a UE, the radio link failure report including an indication that a last completed handover for the UE from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology was for voice fallback purposes. The network node is further configured to perform one or more actions based on the radio link failure report.

[0032] In one embodiment, a network node comprises a communications interface and processing circuitry associated with the communications interface. The processing circuitry is configured to cause the network node to receive a radio link failure report from a UE, the radio link failure report including an indication that a last completed handover for the UE from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology was for voice fallback purposes. The processing circuitry is further configured to cause the network node to perform one or more actions based on the radio link failure report.

[0033] In one embodiment, a method implemented by a UE includes receiving configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes. The method further includes failing to connect to a cell served by the second network node in response to receiving the configuration, and selecting a cell belonging to the second radio access technology in response to the failure to connect to the cell served by the second network node due to the voice fallback indication being configured. The method further includes connecting to the selected cell and declaring a radio link failure in the selected cell. The method further includes storing information related to the radio link failure in a report in response to declaring the radio link failure in the selected cell and the indication that the handover is for voice fallback purposes, the information including an indication that the cell where the radio link failure occurred was selected as part of cell reselection due to the voice fallback indication.

[0034] Corresponding embodiments of a UE are also disclosed. In one embodiment, the UE is configured to receive a configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes. The UE is further configured to fail to connect to a cell served by the second network node in response to receiving the configuration. The UE is further configured to select a cell belonging to the second radio access technology in response to failing to connect to the cell served by the second network node due to the voice fallback indication being configured. The UE is further configured to connect to the selected cell and declare a radio link failure in the selected cell. The UE is further configured to, in response to declaring a radio link failure in the selected cell and the indication indicating that the handover is for voice fallback purposes, store information related to the radio link failure in a report, the information including an indication that the cell in which the radio link failure occurred was selected as part of cell reselection due to the voice fallback indication.

[0035] In one embodiment, a UE comprises a communications interface and a processing circuit associated with the communications interface. The processing circuit is configured to cause the UE to receive a configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes. The processing circuit is further configured to cause the UE to fail to connect to a cell served by the second network node in response to receiving the configuration, and to select a cell belonging to the second radio access technology in response to the failure to connect to the cell served by the second network node due to the voice fallback indication being configured. The processing circuit is further configured to cause the UE to connect to the selected cell and declare a radio link failure in the selected cell. The processing circuitry is further configured to cause the UE, in response to declaring a radio link failure in the selected cell and the indication indicating that the handover is for voice fallback purposes, to store information related to the radio link failure in a report, the information including an indication that the cell in which the radio link failure occurred was selected as part of cell reselection due to the voice fallback indication.

[0036] In one embodiment, a method performed by a network node includes receiving a radio link failure report from a UE, the radio link failure report including an indication that a cell in which a radio link failure occurred has been selected as part of cell reselection with a voice fallback indication, and performing one or more actions based on the radio link failure report.

[0037] Corresponding embodiments of a network node are also disclosed. In one embodiment, the network node is configured to receive a radio link failure report from a UE, the radio link failure report including an indication that the cell in which the radio link failure occurred has been selected as part of cell reselection with a voice fallback indication, and to perform one or more actions based on the radio link failure report.

[0038] In one embodiment, a network node comprises a communications interface and processing circuitry associated with the communications interface, the processing circuitry configured to cause the network node to receive a radio link failure report from a UE, the radio link failure report including an indication that a cell in which a radio link failure occurred has been selected as part of cell reselection with a voice fallback indication, and to perform one or more actions based on the radio link failure report.

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the present disclosure and, together with the description, serve to explain the principles of the disclosure. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 illustrates an Evolved Packet System (EPS) fallback procedure for Internet Protocol (IP) Multimedia Subsystem (IMS) voice, as defined in 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 23.502. [Figure 2] FIG. 1 shows the branching of the self-configuration / self-optimization function and is a reproduction of Figure 22.1-1 of 3GPP TS36.300. [Figure 3] 1 is a flowchart illustrating the operation of a user equipment (UE) for storing in and reporting in a report related to a radio link failure (RLF) an indication of whether the last completed handover was for voice fallback purposes, in accordance with one embodiment of the present disclosure. [Figure 4]10 is a flowchart illustrating a UE operation for storing and reporting an indication that a serving cell experiencing RLF has been selected as part of cell selection due to a voice fallback indication, in accordance with another embodiment of the present disclosure. [Figure 5] 1 is a flowchart illustrating the operation of a network node according to one embodiment of the present disclosure. [Figure 6] FIG. 1 illustrates an example of a communication system in which embodiments of the present disclosure may be implemented. [Figure 7] FIG. 1 illustrates a UE, according to some embodiments. [Figure 8] FIG. 1 illustrates a network node, according to some embodiments. [Figure 9] 7 is a block diagram of a host that may be an embodiment of host 616 in FIG. 6 in accordance with various aspects described herein. [Figure 10] FIG. 1 is a block diagram illustrating a virtualized environment in which functionality implemented by some embodiments may be virtualized. [Figure 11] FIG. 1 is a communication diagram of a host communicating with a UE via a network node over a partial wireless connection, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0041] The embodiments described below represent information to enable those skilled in the art to practice the embodiments and illustrate the best modes for practicing the embodiments. Upon reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts not specifically addressed herein. It is understood that these concepts and applications fall within the scope of the present disclosure.

[0042] Currently, a problem(s) exists where a New Radio (NR) node triggers a user equipment (UE) to perform an inter-radio access technology (RAT) handover to Enhanced Universal Terrestrial Radio Access (E-UTRA) (i.e., to Long Term Evolution (LTE)) for normal mobility-related reasons (going out of NR coverage) or for voice fallback purposes. These two types of NR-to-LTE handovers may involve different mobility decision-making algorithms, as these handovers may be triggered based on different input information available to the source NR node.

[0043] Consider the following scenarios with different UEs: Scenario 1: 1. UE-1 is in a Radio Resource Control (RRC) connected state in NR cell A. 2. UE-1 sends one or more measurement reports, from which the network infers that UE-1 is traveling out of NR coverage and has available LTE coverage. 3. NR cell A sends an inter-RAT handover command to send UE-1 to LTE cell B. 4. UE-1 successfully completes handover to LTE Cell B 5. Shortly after, UE-1 declares a Radio Link Failure (RLF) in LTE Cell B. 6. UE-1 generates an RLF report in E-UTRA indicating that the final source cell of the handover was NR cell A and that UE-1 remained in LTE cell B for a very short time after such handover. Scenario 2: 1. UE-2 is in RRC inactive / RRC idle state in NR cell A. 2. There is a request for a voice call to be initiated towards UE-2, which needs to be sent to LTE 3. NR cell A pages UE-2 4. The NR cell may not have enough time to configure and perform radio resource management (RRM) measurements on the LTE frequency, so the UE immediately triggers a handover (HO) to the LTE cell, Cell B, for voice fallback reasons upon transition to connected. 5. The UE successfully completes handover to LTE cell B. 6. Shortly thereafter, the UE declares RLF in LTE cell B. 7. The UE generates an RLF report in E-UTRA indicating that the final source cell of the handover was NR cell A and that the UE remained in LTE cell B for a very short time after such handover.

[0044] Based on the current RLF report content, a handover from cell A to cell B may be considered "premature" or a "handover to the wrong cell." However, based on the current RLF report content, it is not possible to identify whether the previously completed handover was for voice fallback purposes. This requires performing NR-LTE inter-RAT handover parameter optimization because the NR node may use different handover parameters for normal NR-LTE mobility versus voice fallback-related NR-LTE mobility (since the amount of information available on the NR node is much less for Scenario-2 compared to Scenario-1).

[0045] Some aspects of the present disclosure and embodiments thereof may provide solutions to these or other problems. The systems and methods disclosed herein relate to extending RLF reporting with an indication of whether the last successfully completed handover was a voice fallback-related NR-LTE handover or another type of NR-LTE handover.

[0046] In another scenario, the UE includes in the RLF report an indication that the UE experienced an HO failure that led to a preferred E-UTRA cell selection (due to the voice fallback setting in the MobilityFromNR command) before experiencing the current RLF.

[0047] In one embodiment, the method performed by the UE includes one or more of the following. receiving a configuration for performing a handover from a first network node (e.g., a source NR network node) belonging to a first radio access technology to a second network node (e.g., an LTE network node) belonging to a second radio access technology, the configuration including an indication indicating a voice fallback intent (e.g., MobilityFromNR with voice fallback indication); Connecting to a cell served by a second network node Declaring a radio link failure in a cell served by the second network node. storing a first set of information related to the radio link failure in a first report, the first set of information including at least one or more of the following: o An indication indicating whether the last completed handover from the first network node to the second network node was for voice fallback purposes. In one embodiment, the first report is an RLF report. In one embodiment, the RLF report is logged and included in VarRLF-Report. In one embodiment, once the UE selects a cell and is successfully re-established, the UE sends an RLF report to the respective network node. More specifically, in one embodiment, once the UE selects a cell and is successfully re-established, the UE includes an indication that the UE has an RLF report available in an RRC re-establishment complete message, which makes the target cell aware of its availability. Then, upon receiving a UEInformationRequest message with a flag (e.g., flag "rlf-ReportReq-r9"), the UE includes the RLF report (stored in the UE variable VarRLF-Report, as described above) in the UEInformationResponse message and sends the UEInformationResponse message to the network.

[0048] In another embodiment, the second method performed by the UE includes one or more of the following: receiving a configuration for performing a handover from a first network node (e.g., a source NR node) belonging to a first radio access technology to a second network node (e.g., an LTE network node) belonging to a second radio access technology, the configuration including an indication of a voice fallback purpose (e.g., MobilityFromNR with voice fallback indication); Failure to connect to a cell served by a second network node (e.g., failure in handover execution) Finding a suitable E-UTRA cell and connecting to this selected E-UTRA cell, with voice fallback indication set as part of the received MobilityFromNR command. Declaring a radio link failure in the selected E-UTRA cell after cell selection and connection to the selected E-UTRA cell. storing a first set of information related to the radio link failure in a first report, the first set of information including at least one or more of the following: o An indication indicating that the serving cell from which this RLF was generated was selected as part of cell selection due to a voice fallback indication received as part of the MobilityFromNR command.

[0049] In one embodiment, the first report is an RLF report. In one embodiment, the RLF report is logged and included in VarRLF-Report. In one embodiment, once the UE selects a cell and is successfully re-established, the UE sends an RLF report to the respective network node. More specifically, in one embodiment, once the UE selects a cell and is successfully re-established, the UE includes an indication that the UE has an RLF report available in an RRC re-establishment complete message, which makes the target cell aware of its availability. Then, upon receiving a UEInformationRequest message with a flag (e.g., flag "rlf-ReportReq-r9"), the UE includes the RLF report (stored in the UE variable VarRLF-Report, as described above) in the UEInformationResponse message and sends the UEInformationResponse message to the network.

[0050] Some embodiments may provide one or more of the following technical advantage(s): Based on the additional content of the RLF report proposed in the embodiments described herein, the network can identify whether the last completed handover was a voice fallback handover or not, and thus, if such a handover is classified as a premature handover or a handover to a wrong cell, the network node can optimize voice fallback handover related mobility parameters.

[0051] In some embodiments, by including a flag in the RLF report that the UE failed in the handover leading to E-UTRA cell selection before the current RLF (due to the voice fallback indication / configuration in the MobilityFromNR command), the NR node understands that the voice fallback procedure was not effective (even if successful) because the UE failed after selecting and connecting to an LTE cell after the HO failure.

[0052] Disclosed herein are systems and methods for extending RLF reporting with an indication of whether the last successfully completed handover was a voice fallback-related RAT1 (e.g., NR)-RAT2 (e.g., LTE) handover or another type of RAT1 (e.g., NR)-RAT2 (e.g., LTE) handover.

[0053] In another scenario, the UE includes in the RLF report an indication that the UE experienced an HO failure that led to a preferred EUTRA cell selection (due to the voice fallback setting in the MobilityFromNR command) before experiencing the current RLF.

[0054] 3 is a flowchart illustrating the operation of a UE according to one embodiment of the present disclosure. Optional steps are represented by dashed lines / boxes. As shown, the UE receives a configuration for performing a handover from a first network node (e.g., a source NR network node, e.g., a Next Generation Node B (gNB)) belonging to a first radio access technology (e.g., NR) to a second network node (e.g., an LTE network node, e.g., an evolved or enhanced Node B (eNB)) belonging to a second radio access technology (e.g., LTE), the configuration including an indication indicating a voice fallback intent (e.g., MobilityFromNR with voice fallback indication) (step 300).

[0055] The UE connects to a cell served by a second network node according to the received configuration (step 302). The UE declares RLF in the cell served by the second network node (step 304) and, in response, stores a first set of information related to RLF in a first report (e.g., an RLF report) (step 306). The first set of information includes an indication indicating whether the last completed handover from the first network node to the second network node was for voice fallback purposes. In this example, since the last completed handover was for voice fallback purposes, the indication indicates that the last completed handover from the first network node to the second network node was for voice fallback purposes. In one embodiment, the first report is an RLF report. In one embodiment, the RLF report (in step 306) is logged and included in a VarRLF-Report.

[0056] In one embodiment, the UE selects a cell, successfully re-establishes to the selected cell (step 308), and sends an RLF report to the respective network node (step 310). More specifically, in one embodiment, once the UE selects a cell and successfully re-establishes, the UE includes an indication that the UE has an RLF report available in an RRC re-establishment complete message (step 310A), which makes the target cell aware of its availability. Then, upon receiving a UEInformationRequest message with a flag (e.g., flag "rlf-ReportReq-r9") (step 310B), the UE includes the RLF report (stored in the UE variable VarRLF-Report, as described above) in the UEInformationResponse message and sends the UEInformationResponse message to the network (step 310C).

[0057] 4 is a flowchart illustrating the operation of a UE according to another embodiment of the present disclosure. Optional steps are represented by dashed lines / boxes. As shown, the UE receives a configuration for performing a handover from a first network node (e.g., a source NR network node, e.g., a gNB) belonging to a first radio access technology (e.g., NR) to a second network node (e.g., an LTE network node, e.g., a gNB) belonging to a second radio access technology (e.g., LTE), the configuration including an indication of a voice fallback purpose (e.g., MobilityFromNR with voice fallback indication) (step 400). The UE fails to connect to a cell served by the second network node (e.g., failure in handover execution) (step 402). With the voice fallback indication set as part of the received MobilityFromNR command, the UE finds a suitable EUTRA cell and connects to the selected EUTRA cell (step 404).

[0058] After cell selection and connection to the selected EUTRA cell, the UE declares RLF in the selected EUTRA cell (step 406). In response, the UE stores a first set of information related to the RLF in a first report (step 408). The first set of information includes at least an indication that the serving cell where the RLF occurred was selected as part of the cell selection due to a voice fallback indication received as part of the MobilityFromNR command. In one embodiment, the first report is an RLF report. In one embodiment, the RLF report (in step 408) is logged and included in a VarRLF-Report.

[0059] In one embodiment, the UE selects a cell, successfully re-establishes to the selected cell (step 410), and sends an RLF report to the respective network node (step 412). More specifically, in one embodiment, once the UE selects a cell and successfully re-establishes, the UE includes an indication that the UE has an RLF report available in an RRC re-establishment complete message (step 412A), which makes the target cell aware of its availability. Then, upon receiving a UEInformationRequest message with a flag (e.g., flag "rlf-ReportReq-r9") (step 412B), the UE includes the RLF report (stored in the UE variable VarRLF-Report, as described above) in the UEInformationResponse message and sends the UEInformationResponse message to the network (step 412C).

[0060] 5 is a flowchart illustrating the operation of a network node (e.g., a base station, such as a gNB or eNB) in accordance with one embodiment of the present disclosure. Optional steps are represented by dashed lines / boxes. As shown, the network node receives an RLF report from a UE that includes either (a) an indication that the last completed handover for a first network node to a second network node was for voice fallback purposes, or (b) an indication that a cell where a radio link failure occurred was selected as part of cell reselection due to a voice fallback indication (step 500). The network node may then perform one or more actions based on the RLF report (step 502). The one or more actions may include, for example, sending the RLF report or information from the RLF report to one or more other network nodes (e.g., the first network node). Based on the RLF report, the network (e.g., a network node or some other network node to which the RLF report or the information contained therein is sent) can, for example, identify whether the last completed handover was a voice fallback handover, and thus, if such a handover is classified as a premature handover or a handover to a wrong cell, the network can optimize voice fallback handover-related mobility parameters. In some embodiments, by including a flag in the RLF report that the UE failed in a handover leading to a EUTRA cell selection before the current RLF (due to the voice fallback indication / configuration in the MobilityFromNR command), the NR node understands that the voice fallback procedure was not effective (even if successful) because the UE failed after selection and connection to an LTE cell after an HO failure, and, for example, one or more appropriate actions can be taken.

[0061] An example implementation is given below (TS36.331 v17.0.0 is taken as the baseline, additions are indicated in bold underlined text): *****BEGIN OF EXAMPLE***** -UEInformationResponse The UEInformationResponse message is used by the UE to transfer information requested by the E-UTRAN. Signaling Radio Bearer: SRB1 or SRB2 (when logged measurement information is included) RLC-SAP:AM Logical channel: DCCH Direction: UE to E-UTRAN UEInformationResponse Message TIFF2025529709000002.tif216170TIFF2025529709000003.tif242170TIFF2025529709000004.tif105170TIFF2025529709000005.tif421705.3.11.3 Radio link failure detection The UE shall: 1> If any DAPS bearer is configured, only the target PCell is considered below. 1> Upon expiration of T310, or 1> Upon expiration of T312, or 1> Upon expiration of T318, or 1> When there is a random access problem indication from the MCG MAC while neither T300, T301, T304 nor T311 is running, or 1> Upon an indication from the MCG RLC that the maximum number of retransmissions for an SRB or DRB that are allowed to be sent on the PCell has been reached, 2> Radio link failure is detected for the MCG, i.e., it is considered RLF. 2> Discard any segments of the received segmented RRC message. 2> Store the following radio link failure information in VarRLF-Report (VarRLF-Report-NB in ​​NB-IoT) by setting its fields as follows: 3> Clear the information contained in the VarRLF-Report (VarRLF-Report-NB in ​​NB-IoT), if any. 3> Set plmn-IdentityList to contain the list of EPLMNs stored by the UE (i.e., contain RPLMN). 3> Set measResultLastServCell to contain RSRP and RSRQ, if available, of the PCell based on measurements collected up to the moment the UE detected the radio link failure. 3> Except for NB-IoT, set measResultNeighCells to contain the best measured cells, other than the PCell, ordered so that the best cell is listed first, and based on the measurements collected up to the moment the UE detected the radio link failure, and set its fields as follows: 4> Contains measResultListEUTRA if the UE is configured to perform measurements on one or more EUTRA frequencies. 4> Contains measResultListUTRA if the UE is configured to perform measurement reporting for one or more neighboring UTRA frequencies. 4> Contains measResultListGERAN if the UE is configured to perform measurement reporting for one or more neighboring GERAN frequencies. 4> Contains measResultsCDMA2000 if the UE is configured to perform measurement reporting for one or more neighboring CDMA2000 frequencies. 4> If the UE is configured to perform measurement reporting not related to NR sidelink communication for one or more neighboring NR frequencies, include measResultListNR. 4> For each neighbor cell included, include optional fields that are available. 1> (Note 1) The measured quantities are filtered by the L3 filter as configured in the mobility measurement configuration. The measurements are based on time domain measurement resource limitations, if configured. Exclude-listed cells are not required to be reported. 3> Set logMeasResultListWLAN to contain WLAN measurement results in descending order of RSSI for WLAN APs, excluding NB-IoT, if available. 3> Set logMeasResultListBT to contain the Bluetooth measurement results in descending order of RSSI for Bluetooth beacons, excluding NB-IoT, if available. 3> If detailed location information is available, set the content of locationInfo as follows: 4>Contains locationCoordinates. 4> Includes horizontalVelocity if available. 3> Set failedPCellId to the global cell identity if available, otherwise set it to the physical cell identity and carrier frequency of the PCell where the radio link failure was detected, except for NB-IoT. 3> Except for NB-IoT, set tac-FailedPCell to the tracking area code, if available, of the PCell where the radio link failure was detected. 3> Except for NB-IoT, if an RRCConnectionReconfiguration message containing mobilityControlInfo was received before the connection failure, 4> If the last RRCConnectionReconfiguration message containing mobilityControlInfo was related to an intra-E-UTRA handover, 5> Include previousPCellId and set previousPCellId to the global cell identity of the PCell on which the last RRCConnectionReconfiguration message containing mobilityControlInfo was received. 5> Set timeConnFailure to the time elapsed since the last RRCConnectionReconfiguration message containing mobilityControlInfo was received. 4> If the last RRCConnectionReconfiguration message containing mobilityControlInfo was related to a handover from UTRA to E-UTRA and if the UE supports radio link failure reporting for inter-RAT MRO, 5> Include previousUTRA-CellId and set previousUTRA-CellId to the physical cell identity, carrier frequency and global cell identity, if available, of the UTRA cell in which the last RRCConnectionReconfiguration message containing mobilityControlInfo was received. 5> Set timeConnFailure to the time elapsed since the last RRCConnectionReconfiguration message containing mobilityControlInfo was received. 4> If the last RRCConnectionReconfiguration message containing mobilityControlInfo was related to a handover from NR to E-UTRA and the UE supports radio link failure reporting for inter-RAT MRO NR, 5> Include the previousNR-PCellId and set the previousNR-PCellId to the global cell identity of the PCell on which the last RRCConnectionReconfiguration message was received, including mobilityControlInfo embedded in the NR RRC message MobilityFromNRCommand message as specified in TS38.331

[82] clause 5.4.3.3. 5> Set timeConnFailure to the time elapsed since the reception of the last RRCConnectionReconfiguration message containing mobilityControlInfo embedded in the NR RRC message MobilityFromNRCommand message as specified in TS38.331

[82] clause 5.4.3.3. 5> If voiceFallbackIndication is set to true in the MobilityFromNRCommand that carried the RRCConnectionReconfiguration message containing mobilityControlInfo, 6> Set lastHOType to voiceFallBack. 5> If the failed cell is selected after a failure of MobilityFromNRCommand carrying an RRCConnectionReconfiguration message with voiceFallbackIndication set to true (Preferred EUTRA cell selection by voiceFallBackIndication), 6> Set SelectedCellVoiceFallback to true. 3> Except for NB-IoT, if the UE supports QCI1 indication in radio link failure reporting and has a DRB with QCI=1, 4> Include drb-EstablishedWithQCI-1. 3> Set connectionFailureType to rlf, except for NB-IoT. 3> Except for NB-IoT, set c-RNTI to the C-RNTI used in the PCell. 3> Except for NB-IoT, set rlf-Cause to the trigger for detecting radio link failure. 2> (NG)EN-DC is configured in the UE, and 2> If T316 is set, and 2> If SCG transmission is not interrupted, and 2> If neither an NR PSCell change nor an NR PSCell addition is in progress (i.e., T304 for the NR PSCell is not running as specified in TS 38.331

[82] , clause 5.3.5.5.2 in (NG)EN-DC), 3> Initiate the MCG Fault Information procedure as specified in 5.6.26 to report the MCG radio link failure. 2> If not, 3> If AS security was not activated, 4> If the UE is an NB-IoT UE, 5> If the UE is connected to the EPC and the UE supports RRC connection re-establishment for control plane CIoT EPS optimization, or 5> If the UE is connected to 5GC, the UE supports RRC connection re-establishment for control plane CIoT 5GS optimization, and the UE is configured with a truncated 5G-S-TMSI, 6> Initiate the RRC connection re-establishment procedure as specified in 5.3.7. 5> If not, 6> Upon exiting RRC_CONNECTED as specified in 5.3.12 with release cause "RRC connection failure", perform the actions. 4> If not, 5> Upon exiting RRC_CONNECTED as specified in 5.3.12 with release cause "other", perform the actions. 3> If not, 4> Initiate the connection re-establishment procedure as specified in 5.3.7. ... *****END OF EXAMPLE*****

[0062] FIG. 6 is a diagram illustrating an example of a communication system 600 in which embodiments of the present disclosure may be implemented.

[0063] In this example, the communications system 600 includes a communications network 602 including an access network 604, such as a radio access network (RAN), and a core network 606 including one or more core network nodes 608. The access network 604 includes one or more access network nodes (one or more of which may be generally referred to as network nodes 610), such as network nodes 610A and 610B, or any other similar Third Generation Partnership Project (3GPP) access nodes or non-3GPP access points (APs). The network nodes 610 facilitate direct or indirect connectivity of user equipment (UE), such as by connecting UEs 612A, 612B, 612C, and 612D (one or more of which may be generally referred to as UEs 612), to the core network 606 over one or more wireless connections.

[0064] Exemplary wireless communication over a wireless connection includes sending and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, communication system 600 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals, whether via a wired or wireless connection. Communication system 600 may include and / or interface with any type of communication, telecommunication, data, cellular, wireless network, and / or other similar type systems.

[0065] The UE 612 may be any of a wide variety of communication devices, including a wireless device configured, configured, and / or operable to communicate wirelessly with the network node 610 and other communication devices. Similarly, the network node 610 is configured, capable, configured, and / or operable to communicate, directly or indirectly, with the UE 612 and / or with other network nodes or equipment in the communication network 602 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration, in the communication network 602.

[0066] In the illustrated example, the core network 606 connects the network node 610 to one or more hosts, such as the host 616. These connections may be direct or indirect via one or more intermediate networks or devices. In other examples, the network node may be directly coupled to the host. The core network 606 includes one or more core network nodes (e.g., the core network node 608) structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, and therefore, those descriptions are generally applicable to the corresponding components of the core network node 608. Exemplary core network nodes include one or more of a Mobile Switching Center (MSC), a Mobility Management Entity (MME), a Home Subscriber Server (HSS), an Access and Mobility Management Function (AMF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Subscription Identifier De-Concealing Function (SIDF), a Unified Data Management (UDM), a Security Edge Protection Proxy (SEPP), a Network Publishing Function (NEF), and / or a User Plane Function (UPF).

[0067] The host 616 may be owned or under the control of, and operated by or on behalf of, a service provider other than the operator or provider of the access network 604 and / or the communication network 602. The host 616 may host various applications to provide one or more services. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data about various ambient conditions detected by multiple UEs, analytics functions, social media, functions for controlling or possibly interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0068] Overall, the communication system 600 of FIG. 6 enables connectivity between UEs, network nodes, and hosts. In that sense, the communication system 600 may be configured to operate according to predefined rules or procedures, such as a particular standard, including, but not limited to, Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), and / or other suitable second, third, fourth, or fifth generation (2G, 3G, 4G, or 5G) standard, or any applicable future generation standard (e.g., sixth generation (6G)), a wireless local area network (WLAN) standard such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard (WiFi), and / or any low power wide area network (LPWAN) standard such as Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, near field communications (NFC) ZigBee, LiFi, and / or LoRa and Sigfox.

[0069] In some examples, the communication network 602 is a cellular network that implements 3GPP standardized features. Thus, the communication network 602 may support network slicing to provide different logical networks to different devices connected to the communication network 602. For example, the communication network 602 may provide Ultra-Reliable Low Latency Communication (URLLC) services to some UEs, while providing enhanced Mobile Broadband (eMBB) services to other UEs and / or providing Massive Machine-Based Communication (mMTC) / Massive Internet of Things (IoT) services to still further UEs.

[0070] In some examples, the UE 612 is configured to transmit and / or receive information without direct human interaction. For example, the UE may be designed to transmit information to the access network 604 on a predetermined schedule, when triggered by an internal or external event, or in response to a request from the access network 604. Furthermore, the UE may be configured to operate in a single or multi-radio access technology (RAT) or multi-standard mode. For example, the UE may operate with any one or a combination of Wi-Fi, New Radio (NR), and LTE, i.e., Multi-Radio Dual Connectivity (MR-DC), such as Enhanced UMTS Terrestrial RAN (E-UTRAN) NR-Dual Connectivity (EN-DC).

[0071] In this example, a hub 614 communicates with the access network 604 to facilitate indirect communication between one or more UEs (e.g., UEs 612C and / or 612D) and a network node (e.g., network node 610B). In some examples, the hub 614 may be a controller, a router, a content source, a content analyzer, or any of the other communication devices described herein with respect to UEs. For example, the hub 614 may be a broadband router that enables access to the core network 606 for the UE. As another example, the hub 614 may be a controller that sends commands or instructions to one or more actuators in the UE. The commands or instructions may be received from the UE, the network node 610, or may be due to executable code, scripts, processes, or other instructions in the hub 614. As another example, the hub 614 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 614 may be a content source. For example, for a UE that is a virtual reality (VR) headset, display, loudspeaker, or other media distribution device, the hub 614 may retrieve, via a network node, VR assets, video, audio, or other media or data related to sensory information, which the hub 614 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In yet another example, the hub 614 acts as a proxy server or orchestrator for the UEs, particularly in the case where one or more of the UEs are low-energy IoT devices.

[0072] The hub 614 may have a constant / permanent or intermittent connection to the network node 610B. The hub 614 may also enable different communication schemes and / or schedules between the hub 614 and the UEs (e.g., UEs 612C and / or 612D) and between the hub 614 and the core network 606. In other examples, the hub 614 is connected to the core network 606 and / or one or more UEs via a wired connection. Moreover, the hub 614 may be configured to connect to a machine-to-machine (M2M) service provider over the access network 604 and / or to another UE over a direct connection. In some scenarios, a UE may establish a wireless connection with the network node 610 while still connected via a wired or wireless connection through the hub 614. In some embodiments, the hub 614 may be a dedicated hub, i.e., a hub whose primary function is to route communications from / to the UE to / from the network node 610B. In other embodiments, the hub 614 may be a non-dedicated hub, i.e., a device that is capable of operating to route communications between the UE and the network node 610B, but that is further capable of operating as a communication initiation and / or termination point for some data channels.

[0073] 7 illustrates a UE 700, according to some embodiments. As used herein, a UE refers to a device capable of, set up, configured, and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smartphone, a mobile phone, a cell phone, a Voice over Internet Protocol (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless camera, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop computer, a laptop embedded equipment (LEE), a laptop mounted equipment (LME), a smart device, a wireless customer premises equipment (CPE), a vehicle-mounted or vehicle-embedded / integrated wireless device, etc. Other examples include any UE identified by 3GPP, including a Narrowband Internet of Things (NB-IoT) UE, a Machine Type Communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0074] A UE may support device-to-device (D2D) communications, for example, by implementing 3GPP standards for sidelink communications, dedicated short-range communications (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE does not necessarily have a user in the sense of a human user who owns and / or operates an associated device. Instead, a UE may represent a device (e.g., a smart sprinkler controller) that is intended for sale to or operation by a human user, but may not be associated with or initially associated with a particular human user. Alternatively, a UE may represent a device (e.g., a smart power meter) that is not intended for sale to or operation by an end user, but may be associated with or operated for the user's benefit.

[0075] The UE 700 includes a processing circuit 702 operably coupled to an input / output interface 706, a power source 708, a memory 710, a communication interface 712, and / or any other components, or any combination thereof, via a bus 704. Some UEs may utilize all or a subset of the components shown in FIG. 7. The level of integration between components may vary from UE to UE. Additionally, some UEs may include multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0076] The processing circuit 702 is configured to process instructions and data and may be configured to implement any sequential state machine operable to execute instructions stored in memory 710 as a machine-readable computer program. The processing circuit 702 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), etc.), programmable logic together with appropriate firmware, one or more stored computer programs such as a microprocessor or digital signal processor (DSP) together with appropriate software, a general-purpose processor, or any combination of the above. For example, the processing circuit 702 may include multiple central processing units (CPUs).

[0077] In this example, the input / output interface 706 may be configured to provide one or more interfaces to an input device, an output device, or one or more input and / or output devices. Examples of output devices include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smart card, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 700. Examples of input devices include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a webcam, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smart card, etc. A presence-sensitive display may include a capacitive or resistive touch sensor for detecting input from a user. The sensor may be, for example, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, a light sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as the input device. For example, a universal serial bus (USB) port may be used to accommodate input and output devices.

[0078] In some embodiments, the power source 708 is structured as a battery or battery pack. Other types of power sources may be used, such as an external power source (e.g., an electrical outlet), a photovoltaic device, or a battery. The power source 708 may further include power circuitry for delivering power to various portions of the UE 700 from the power source 708 itself and / or from an external power source via an input circuit or an interface such as a power cable. Delivering power may be for charging the power source 708, for example. The power circuitry may perform any formatting, conversion, or other modification on the power from the power source 708 to make it suitable for each component of the UE 700 being powered.

[0079] The memory 710 may be or be configured to include memory, such as random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrical EPROM (EEPROM), magnetic disk, optical disk, hard disk, removable cartridge, flash drive, etc. In one example, the memory 710 includes one or more application programs 714, such as an operating system, a web browser application, a widget, a gadget engine, or other applications, and corresponding data 716. The memory 710 may store any of a variety of different operating systems or combinations of operating systems for use by the UE 700.

[0080] The memory 710 may be configured to include several physical drive units, such as a redundant array of independent disks (RAID), flash memory, a USB flash drive, an external hard disk drive, a thumb drive, a pen drive, a key drive, a high-density digital versatile disc (HD-DVD) optical disc drive, an internal hard disk drive, a Blu-ray optical disc drive, a holographic digital data storage (HDDS) optical disc drive, an external mini dual in-line memory module (DIMM), a synchronous dynamic random access memory (SDRAM), an external micro-DIMM SDRAM, a smart card memory, such as a tamper-resistant module in the form of a universal integrated circuit card (UICC) containing one or more SIMs, such as a universal subscriber identity module (SIM) (USIM) and / or an Internet Protocol Multimedia Services Identity Module (ISIM), other memory, or any combination thereof. The UICC may be, for example, an embedded UICC (eUICC), an integrated UICC (iUICC), or a removable UICC, commonly known as a "SIM card." The memory 710 may enable the UE 700 to access, offload, or upload data, instructions, application programs, etc. stored on a temporary or non-transitory memory medium. An article of manufacture, such as an article of manufacture utilizing a communication system, may be tangibly embodied as or in the memory 710, which may be or comprise a device-readable storage medium.

[0081] The processing circuit 702 may be configured to communicate with an access network or other networks using a communication interface 712. The communication interface 712 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 722. The communication interface 712 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or network node in the access network). Each transceiver may include a transmitter 718 and / or a receiver 720 suitable for providing network communication (e.g., optical, electrical, frequency allocation, etc.). Moreover, the transmitter 718 and receiver 720 may be coupled to one or more antennas (e.g., antenna 722) and may share circuit components, software, or firmware, or may alternatively be implemented separately.

[0082] In the illustrated embodiment, the communication capabilities of communication interface 712 may include cellular communication, WiFi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communication such as Bluetooth, NFC, location-based communication such as using a Global Positioning System (GPS) to determine location, another similar communication capability, or any combination thereof. Communications may be implemented in accordance with one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiple Access (CDMA), Wideband CDMA (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, Transmission Control Protocol / Internet Protocol (TCP / IP), Synchronous Optical Networking (SONET), Asynchronous Transfer Mode (ATM), Quick User Datagram Protocol Internet Connection (QUIC), Hypertext Transfer Protocol (HTTP), etc.

[0083] Regardless of the type of sensor, the UE may provide an output of data captured by the UE's sensors to a network node through the UE's communications interface 712 or via a wireless connection. Data captured by the UE's sensors may be communicated to a network node via another UE through a wireless connection. The output may be periodic (e.g., once every 15 minutes when reporting detected temperature), in response to a triggering event (e.g., an alert is sent when humidity is detected), in response to a request (e.g., a user-initiated request), random (e.g., to even out the load from reporting from several sensors), or a continuous stream (e.g., a live video feed of a patient).

[0084] As another example, the UE may include an actuator, motor, or switch associated with a communications interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input, the state of the actuator, motor, or switch may change. For example, the UE may include a motor that adjusts a control surface or rotor of a drone in flight according to the received input, or a robotic arm that performs a medical procedure according to the received input.

[0085] When in the form of an IoT device, the UE may be a device for use in one or more application areas, including, but not limited to, urban wearable technology, augmented industrial applications, and healthcare. Non-limiting examples of such IoT devices are devices that are or are embedded in a connected refrigerator or freezer, a television, a connected lighting device, an energy meter, a robotic vacuum cleaner, a voice-controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a water / humidity sensor, an electronic door lock, a connected doorbell, an air conditioning system such as a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for augmented reality (AR) or VR, a wearable for haptic augmentation or sensory augmentation, a water sprinkler, an animal or product tracking device, a sensor for monitoring plants or animals, an industrial robot, an unmanned aerial vehicle (UAV), and any type of medical device such as a heart rate monitor or a remote-controlled surgical robot. A UE in the form of an IoT device comprises, in addition to the other components described with respect to the UE 700 shown in FIG. 7, circuitry and / or software depending on the intended application of the IoT device.

[0086] As yet another particular example, in an IoT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements and transmits results of such monitoring and / or measurements to another UE and / or network node. The UE may in this case be an M2M device, which may be referred to as an MTC device in a 3GPP context. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, bus, truck, ship, airplane, or other equipment capable of monitoring and / or reporting on its operating status or other functionality associated with its operation.

[0087] In practice, any number of UEs may be used together for a single use case. For example, a first UE may be a drone or be integrated in a drone and provide the drone's speed information (obtained through a speed sensor) to a second UE that is a remote controller that operates the drone. When a user makes changes from the remote controller, the first UE may adjust a throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone's speed. The first and / or second UE may also include two or more of the functions described above. For example, a UE may include a sensor and an actuator and handle communication of data for both the speed sensor and the actuator.

[0088] 8 illustrates a network node 800 according to some embodiments. As used herein, a network node refers to a device capable of, set up, configured, and / or operable to communicate, directly or indirectly, with UEs and / or other network nodes or devices in a communication network. Examples of network nodes include, but are not limited to, APs (e.g., wireless APs), base stations (BSs) (e.g., wireless BSs, Node Bs, evolved Node Bs (eNBs), and NR Node Bs (gNBs)).

[0089] BSs may be categorized based on the amount of coverage they provide (or, stated another way, their transmit power level) and may therefore be referred to as femto BSs, pico BSs, micro BSs, or macro BSs depending on the amount of coverage provided. A BS may be a relay node or a relay donor node that controls a relay. A network node may also include one or more (or all) parts of a distributed wireless BS, such as a centralized digital unit and / or a remote radio unit (RRU), sometimes referred to as a remote radio head (RRH). Such RRUs may or may not be integrated with an antenna, such as an antenna-integrated radio. Portions of a distributed wireless BS may also be referred to as nodes in a distributed antenna system (DAS).

[0090] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, MSR equipment such as a multi-standard radio (MSR) BS, a network controller such as a radio network controller (RNC) or a BS controller (BSC), a base transceiver station (BTS), a transmission point, a transmitting node, a multi-cell / multicast coordination entity (MCE), an operation and maintenance (O&M) node, an operation support system (OSS) node, a self-organizing network (SON) node, a positioning node (e.g., an evolved serving mobile location center (E-SMLC)), and / or a minimization of drive test (MDT).

[0091] The network node 800 includes processing circuitry 802, memory 804, a communications interface 806, and a power source 808. The network node 800 may be assembled from multiple physically separate components (e.g., Node B and RNC components, or BTS and BSC components, etc.), each of which may have their own respective components. In some scenarios in which the network node 800 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple Node Bs. In such scenarios, each unique Node B and RNC pair may, in some instances, be considered a single separate network node. In some embodiments, the network node 800 may be configured to support multiple RATs. In such embodiments, some components may be duplicated (e.g., separate memory 804 for different RATs) and some components may be reused (e.g., antenna 810 may be shared by different RATs). Network node 800 may also include multiple sets of the various shown components for different wireless technologies, e.g., GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, Long Range Wide Area Network (LoRaWAN), Radio Frequency Identification (RFID), or Bluetooth wireless technologies, integrated into network node 800. These wireless technologies may be integrated into the same or different chips or sets of chips and other components within network node 800.

[0092] The processing circuitry 802 may comprise one or more combinations of a microprocessor, controller, microcontroller, CPU, DSP, ASIC, FPGA, or any other suitable computing device, resource, or combination of hardware, software, and / or coded logic operable to provide the network node 800 functionality, either alone or in conjunction with other network node 800 components such as memory 804.

[0093] In some embodiments, the processing circuit 802 comprises a system on a chip (SOC). In some embodiments, the processing circuit 802 includes one or more of a radio frequency (RF) transceiver circuit 812 and a baseband processing circuit 814. In some embodiments, the RF transceiver circuit 812 and the baseband processing circuit 814 may be on separate chips (or sets of chips), boards, or units, such as a radio unit and a digital unit. In alternative embodiments, some or all of the RF transceiver circuit 812 and the baseband processing circuit 814 may be on the same chip or set of chips, board, or unit.

[0094] The memory 804 may comprise any form of volatile or non-volatile computer-readable memory, including, but not limited to, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, RAM, ROM, mass storage media (e.g., hard disk), removable storage media (e.g., flash drive, compact disc (CD) or digital video disc (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable, and / or computer-executable memory device that stores information, data, and / or instructions that may be used by the processing circuit 802. The memory 804 may store any suitable instructions, data, or information, including applications including one or more of computer programs, software, logic, rules, code, tables, and / or other instructions that can be executed by the processing circuit 802 and utilized by the network node 800. The memory 804 may be used to store computations performed by the processing circuit 802 and / or data received via the communications interface 806. In some embodiments, the processing circuit 802 and the memory 804 are integrated.

[0095] The communication interface 806 is used in wired or wireless communication of signaling and / or data between network nodes, access networks, and / or the UE. As shown, the communication interface 806 comprises port(s) / terminal(s) 816 for sending and receiving data to and from a network, e.g., over a wired connection. The communication interface 806 also includes radio front-end circuitry 818, which is coupled to an antenna 810 or, in some embodiments, may be part of the antenna 810. The radio front-end circuitry 818 comprises a filter 820 and an amplifier 822. The radio front-end circuitry 818 may be connected to the antenna 810 and the processing circuit 802. The radio front-end circuitry 818 may be configured to condition signals communicated between the antenna 810 and the processing circuit 802. The radio front-end circuitry 818 may receive digital data to be sent to another network node or the UE via a wireless connection. The radio front-end circuitry 818 may convert the digital data into radio signals having appropriate channel and bandwidth parameters using a combination of filters 820 and / or amplifiers 822. The radio signals may then be transmitted via the antenna 810. Similarly, when receiving data, the antenna 810 may collect the radio signals, which are then converted into digital data by the radio front-end circuitry 818. The digital data may be passed to the processing circuit 802. In other embodiments, the communication interface 806 may comprise different components and / or different combinations of components.

[0096] In some alternative embodiments, network node 800 does not include a separate radio front-end circuit 818; instead, processing circuit 802 includes the radio front-end circuitry and is connected to antenna 810. Similarly, in some embodiments, all or a portion of RF transceiver circuitry 812 is part of communication interface 806. In still other embodiments, communication interface 806 includes one or more ports or terminals 816, radio front-end circuitry 818, and RF transceiver circuitry 812 as part of a radio unit (not shown), and communication interface 806 communicates with baseband processing circuitry 814 that is part of a digital unit (not shown).

[0097] Antenna 810 may include one or more antennas or antenna arrays configured to send and / or receive wireless signals. Antenna 810 may be coupled to radio front-end circuitry 818 and may be any type of antenna capable of wirelessly transmitting and receiving data and / or signals. In some embodiments, antenna 810 is separate from network node 800 and connectable to network node 800 through an interface or port.

[0098] The antenna 810, the communication interface 806, and / or the processing circuit 802 may be configured to perform any receiving operation and / or some obtaining operation described herein as being performed by the network node 800. Any information, data, and / or signal may be received from a UE, another network node, and / or any other network equipment. Similarly, the antenna 810, the communication interface 806, and / or the processing circuit 802 may be configured to perform any transmitting operation described herein as being performed by the network node 800. Any information, data, and / or signal may be transmitted to a UE, another network node, and / or any other network equipment.

[0099] The power supply 808 provides power to the various components of the network node 800 in a form suitable for each component (e.g., at the voltage and current levels required for each respective component). The power supply 808 may further comprise, or be coupled to, power management circuitry for supplying power to the components of the network node 800 for performing the functions described herein. For example, the network node 800 may be connectable to an external power source (e.g., a power grid or an electrical outlet) via an input circuit or interface, such as an electrical cable, whereby the external power source supplies power to the power circuitry of the power supply 808. As a further example, the power supply 808 may comprise a power source in the form of a battery or battery pack connected to or integrated in the power circuitry. The battery may provide backup power in the event that the external power source fails.

[0100] Embodiments of network node 800 may include additional components other than those shown in Figure 8 to provide certain aspects of the network node's functionality, including any of the functionality described herein and / or functionality necessary to support the subject matter described herein. For example, network node 800 may include user interface devices to enable input of information into network node 800 and output of information from network node 800. This may enable a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 800.

[0101] 9 is a block diagram of a host 900, which may be an embodiment of the host 616 of FIG. 6 in accordance with various aspects described herein. As used herein, the host 900 may be or comprise various combinations of hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, a container, or processing resources in a server farm. The host 900 may provide one or more services to one or more UEs.

[0102] The host 900 includes a processing circuit 902 operably coupled to an input / output interface 906, a network interface 908, a power supply 910, and a memory 912 via a bus 904. In other embodiments, other components may be included. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as FIGS. 7 and 8, and therefore, those descriptions are generally applicable to the corresponding components of the host 900.

[0103] The memory 912 may include one or more computer programs, including one or more host application programs 914 and data 916, which may include user data, e.g., data generated by the UE for the host 900 or data generated by the host 900 for the UE. An embodiment of the host 900 may utilize only a subset or all of the shown components. The host application programs 914 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), Moving Picture Experts Group (MPEG), VP9) and audio codecs (e.g., Free Lossless Audio Codec (FLAC), Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UE (e.g., handsets, desktop computers, wearable display systems, and heads-up display systems). The host application program 914 may also provide user authentication and license checks, and may periodically report health, route, and content availability to a central node, such as a device in the core network or a device on the edge of the core network. Thus, the host 900 may select and / or direct different hosts for over-the-top (OTT) services for the UE. The host application program 914 may support various protocols, such as HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (DASH or MPEG-DASH), etc.

[0104] FIG. 10 is a block diagram illustrating a virtualization environment 1000 in which functionality implemented by some embodiments may be virtualized. In this context, virtualizing means creating a virtual version of an apparatus or device, which may include virtualizing a hardware platform, storage devices, and networking resources. Virtualization, as used herein, may apply to any device described herein, or components thereof, and relates to implementations in which at least a portion of functionality is implemented as one or more virtual components. Some or all of the functionality described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1000 hosted by one or more of the hardware nodes, such as a network node, a UE, a core network node, or a hardware computing device acting as a host. Furthermore, in embodiments in which the virtual node does not require wireless connectivity (e.g., to a core network node or host), the node may be fully virtualized.

[0105] An application 1002 (which may alternatively be referred to as a software instance, a virtual appliance, a network function, a virtual node, a virtual network function, etc.) is run in the virtualized environment 900 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0106] The hardware 1004 includes processing circuitry, memory that stores software and / or instructions executable by the hardware processing circuitry, and / or other hardware devices described herein, such as network interfaces, input / output interfaces, etc. Software is executed by the processing circuitry to instantiate one or more virtualization layers 1006 (also referred to as a hypervisor or VM monitor (VMM)), provide VMs 1008A and 1008B (one or more of which may be referred to generically as VMs 1008), and / or implement any of the functions, features, and / or benefits described with respect to some embodiments described herein. The virtualization layer 1006 may present to the VMs 1008 a virtual operating platform that appears to be networking hardware.

[0107] The VMs 1008 may comprise virtual processing, virtual memory, virtual networking or interfaces, and virtual storage, and may be run by a corresponding virtualization layer 1006. Different embodiments of the virtual appliance 1002 instance may be implemented on one or more of the VMs 1008, and the implementation may be done in different ways. Hardware virtualization is referred to in some contexts as network functions virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry-standard high-volume server hardware, physical switches, and physical storage that may be located in data centers and customer premises equipment.

[0108] In the context of NFV, a VM 1008 may be a software implementation of a physical machine that runs programs as if those programs were running on a physical, non-virtualized machine. Each VM 1008 and the portion of the hardware 1004 on which it runs, whether hardware dedicated to that VM and / or hardware shared by that VM with other ones of the VMs 1008, form a separate virtual network element. Further, in the context of NFV, a virtual network function is responsible for handling a particular network function running in one or more VMs 1008 on the hardware 1004 and corresponds to the application 1002.

[0109] The hardware 1004 may be implemented in a standalone network node with general or specific components. The hardware 1004 may implement some functions via virtualization. Alternatively, the hardware 1004 may be part of a larger cluster of hardware (e.g., as in a data center or CPE) where many hardware nodes cooperate and are managed via a management and orchestration 1010 that, among other things, oversees the lifecycle management of the application 1002. In some embodiments, the hardware 1004 is coupled to one or more radio units, each including one or more transmitters and one or more receivers, which may be coupled to one or more antennas. The radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with virtual components to provide a virtual node with wireless capabilities, such as a RAN or BS. In some embodiments, some signaling may be provided using a control system 1012, which may alternatively be used for communication between the hardware nodes and the radio units.

[0110] 11 shows a communication diagram of a host 1102 communicating with a UE 1106 via a network node 1104 over a partial wireless connection, according to some embodiments. Exemplary implementations according to various embodiments of a UE (such as UE 612A of FIG. 6 and / or UE 700 of FIG. 7), a network node (such as network node 610A of FIG. 6 and / or network node 800 of FIG. 8), and a host (such as host 616 of FIG. 6 and / or host 900 of FIG. 9) described in the previous paragraphs will now be described with reference to FIG. 11.

[0111] Similar to host 900, an embodiment of host 1102 includes hardware such as a communications interface, processing circuitry, and memory. Host 1102 also includes software stored on or accessible by host 1102 and executable by the processing circuitry. The software includes a host application that may be operable to provide services to a remote user, such as a UE 1106 connecting via an OTT connection 1150 extending between UE 1106 and host 1102. In providing services to a remote user, the host application may provide user data that is transmitted using the OTT connection 1150.

[0112] The network node 1104 includes hardware that enables the network node 1104 to communicate with the host 1102 and the UE 1106 over a connection 1160. The connection 1160 may be direct or may pass through one or more other intermediate networks, such as a core network (similar to the core network 606 of FIG. 6) and / or one or more public, private, or hosted networks. For example, the intermediate network may be a backbone network or the Internet.

[0113] The UE 1106 includes hardware and software stored on or accessible by the UE 1106 and executable by the UE's processing circuitry. The software includes a client application, such as a web browser or operator-specific "app," which, with the support of the host 1102, may be operable to provide services to a human or non-human user via the UE 1106. An executing host application on the host 1102 may communicate with an executing client application via an OTT connection 1150 that terminates at the UE 1106 and the host 1102. In providing services to the user, the UE's client application may receive request data from the host application and provide user data in response to the request data. The OTT connection 1150 may transfer both request data and user data. The UE's client application may interact with the user to generate user data that the UE's client application provides to the host application through the OTT connection 1150.

[0114] The OTT connection 1150 may extend via a connection 1160 between the host 1102 and the network node 1104 and via a wireless connection 1170 between the network node 1104 and the UE 1106 to provide connectivity between the host 1102 and the UE 1106. The connections 1160 and wireless connections 1170 over which the OTT connection 1150 may be provided are depicted abstractly to show communication between the host 1102 and the UE 1106 via the network node 1104, without explicit reference to intermediary devices and the precise routing of messages through these devices.

[0115] As an example of transmitting data over the OTT connection 1150, in step 1108, the host 1102 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1106. In other embodiments, the user data is associated with the UE 1106 sharing data with the host 1102 without explicit human interaction. In step 1110, the host 1102 initiates a transmission carrying user data toward the UE 1106. The host 1102 may initiate the transmission in response to a request sent by the UE 1106. The request may be caused by human interaction with the UE 1106 or by the operation of a client application executing on the UE 1106. The transmission may proceed via the network node 1104 in accordance with the teachings of the embodiments described throughout this disclosure. Thus, in step 1112, the network node 1104 transmits the user data carried in the transmission initiated by the host 1102 to the UE 1106, in accordance with the teachings of embodiments described throughout this disclosure. In step 1114, the UE 1106 receives the user data carried in the transmission, which may be performed by a client application running on the UE 1106 associated with the host application executed by the host 1102.

[0116] In some examples, the UE 1106 executes a client application that provides user data to the host 1102. The user data may be provided in reaction or response to data received from the host 1102. Thus, in step 1116, the UE 1106 may provide the user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from a user via an input / output interface of the UE 1106. Regardless of the particular manner in which the user data is provided, the UE 1106 initiates transmission of the user data towards the host 1102 via the network node 1104 in step 1118. In step 1120, the network node 1104 receives the user data from the UE 1106 and initiates transmission of the received user data towards the host 1102, in accordance with the teachings of embodiments described throughout this disclosure. In step 1122, the host 1102 receives the user data carried in the transmission initiated by the UE 1106.

[0117] One or more of the various embodiments improve the performance of the OTT service provided to the UE 1106 using the OTT connection 1150 of which the radio connection 1170 forms the final segment.

[0118] In an exemplary scenario, factory status information may be collected and analyzed by the host 1102. As another example, the host 1102 may process audio and video data that may have been retrieved from UEs for use in creating maps. As another example, the host 1102 may collect and analyze real-time data to assist in controlling vehicular congestion (e.g., controlling traffic signals). As another example, the host 1102 may store surveillance video uploaded by UEs. As another example, the host 1102 may store or control access to media content, such as video, audio, VR or AR, that the host 1102 may broadcast, multicast, or unicast to UEs. As other examples, the host 1102 may be used for energy pricing, remote control of non-time-critical electrical loads to balance power generation needs, location services, presentation services (such as compiling diagrams, etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing, and / or transmitting data.

[0119] In some examples, measurement procedures may be provided for the purpose of monitoring data rates, latency, and other factors that one or more embodiments improve upon. There may further be optional network functionality for reconfiguring the OTT connection 1150 between the host 1102 and the UE 1106 in response to fluctuations in the measurement results. The measurement procedures and / or the network functionality for reconfiguring the OTT connection 1150 may be implemented in software and hardware in the host 1102 and / or the UE 1106. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 1150 passes, and the sensors may participate in the measurement procedures by providing values ​​of the monitored quantities exemplified above, or other physical quantities from which software can calculate or estimate the monitored quantities. Reconfiguration of the OTT connection 1150 may include message formats, retransmission settings, preferred routing, etc., and the reconfiguration need not directly change the operation of the network node 1104. Such procedures and functionality may be known and practiced in the art. In some embodiments, the measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation time, latency, etc. by the host 1102. The measurements may be implemented in software causing messages, particularly empty or "dummy" messages, to be sent using the OTT connection 1150 while monitoring propagation time, errors, etc.

[0120] While the computing devices (e.g., UEs, network nodes, hosts) described herein may include the depicted combinations of hardware components, other embodiments may comprise computing devices with different combinations of components. It should be understood that these computing devices may comprise any suitable combination of hardware and / or software required to perform the tasks, features, functions, and methods disclosed herein. The determining, calculating, obtaining, or similar operations described herein may be performed by processing circuitry, which may process information by, for example, transforming the obtained information to other information, comparing the obtained or transformed information to information stored in a network node, and / or performing one or more operations based on the obtained or transformed information and as a result of the processing making a decision. Moreover, while a component is illustrated as a single box located within a larger box or nested within multiple boxes, in reality the computing device may comprise multiple different physical components that make up the single depicted component, and functionality may be partitioned among the separate components. For example, a communications interface may be configured to include any of the components described herein, and / or the functionality of those components may be partitioned between the processing circuitry and the communications interface. In another example, non-computationally intensive functionality of any of such components may be implemented in software or firmware, and computationally intensive functionality may be implemented in hardware.

[0121] In some embodiments, some or all of the functionality described herein may be provided by a processing circuit executing instructions stored in a memory, which in some embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuit without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hardwired manner. In any of these particular embodiments, the processing circuit may be configured to perform the described functionality, regardless of whether or not it executes instructions stored on a non-transitory computer-readable storage medium. Benefits provided by such functionality are not limited to the processing circuit alone or to other components of the computing device, but are enjoyed by the computing device as a whole and / or by end users and wireless networks generally.

[0122] Some exemplary embodiments of the present disclosure are as follows.

[0123] Group A Embodiments Embodiment 1: A method implemented by a user equipment (UE), the method comprising: receiving (300) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), connecting (302) to a cell served by a second network node; Declaring (304) a radio link failure in a cell served by the second network node; storing (306) information related to the radio link failure in a report in response to declaring (304) a radio link failure in a cell served by the second network node and an indication that the handover is for voice fallback purposes, the information including an indication that the last completed handover for the first network node to the second network node was for voice fallback purposes; and A method comprising:

[0124] Embodiment 2: The method of embodiment 1, wherein the first radio access technology is New Radio (NR) and the second radio access technology is Long Term Evolution (LTE).

[0125] Embodiment 3: The method of embodiment 1 or 2, wherein the report is a radio link failure report.

[0126] Embodiment 4: The method of any one of embodiments 1 to 3, further comprising: selecting a cell (308); reconnecting to the cell (308); and sending a report to a network node associated with the cell (310).

[0127] Embodiment 5: A method implemented by a user equipment (UE), the method comprising: receiving 400 a configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), failing (402) to connect to a cell served by the second network node; In response to a failure to connect to a cell served by a second network node (402) due to a voice fallback indication being set (e.g., as part of a received MobilityFromNR command), selecting (404) a cell belonging to a second radio access technology; Connecting to the selected cell (404); Declaring a radio link failure in the selected cell (406); storing (408) information related to the radio link failure in a report in response to declaring (406) a radio link failure in the selected cell and an indication that the handover is for voice fallback purposes, the information including an indication that the cell in which the radio link failure occurred was selected as part of cell reselection due to a voice fallback indication (e.g., received as part of a received MobilityFromNR command); A method comprising:

[0128] Embodiment 6: The method of embodiment 5, wherein the first radio access technology is New Radio (NR) and the second radio access technology is Long Term Evolution (LTE).

[0129] Embodiment 7: The method of embodiment 5 or 6, wherein the report is a radio link failure report.

[0130] Embodiment 8: The method of any one of embodiments 5 to 7, further comprising: selecting a cell (410); reconnecting to the cell (410); and sending a report to a network node associated with the cell (412).

[0131] Embodiment 9: The method of any one of embodiments 1 to 8, further comprising providing user data and forwarding the user data to the host via transmission to the network node.

[0132] Group B Embodiments Embodiment 10: A method implemented by a network node, the method including receiving (500) from a user equipment (UE) a radio link failure report including either (a) an indication that a last completed handover for a first network node to a second network node was for voice fallback purposes, or (b) an indication that a cell where a radio link failure occurred was selected as part of cell reselection due to a voice fallback indication.

[0133]

[0023] Embodiment 11: The method of embodiment 10, further comprising: performing one or more actions based on the radio link failure report (502).

[0134] Embodiment 12: The method of embodiment 10 or 11, further including obtaining user data and forwarding the user data to a host or user equipment.

[0135] Group C Embodiments Embodiment 13: A user equipment, comprising: processing circuitry configured to perform any of the steps recited in any one of the embodiments of Group A; a power supply circuit configured to supply power to the processing circuit; A user equipment comprising:

[0136] Embodiment 14: A network node, comprising: processing circuitry configured to perform any of the steps recited in any one of the embodiments of Group B; a power supply circuit configured to supply power to the processing circuit; A network node comprising:

[0137] Embodiment 15: A user equipment (UE), comprising: an antenna configured to transmit and receive radio signals; a radio front-end circuit coupled to the antenna and the processing circuit and configured to condition signals communicated between the antenna and the processing circuit; a processing circuit configured to perform any of the steps recited in any one of the embodiments of Group A; a radio front-end circuit; an input interface coupled to the processing circuitry and configured to enable input of information to the UE to be processed by the processing circuitry; an output interface coupled to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; a battery and a processing circuit connected to the UE and configured to power the UE; A user equipment (UE) comprising:

[0138]

[0033] Embodiment 16: A host configured to operate in a communication system for providing over-the-top (OTT) services, the host comprising: processing circuitry configured to provide user data; a network interface configured to initiate transmission of user data to a cellular network for transmission to a user equipment (UE); Equipped with a UE comprising a communications interface and processing circuitry, the communications interface and processing circuitry of the UE configured to perform any of the steps recited in any one of the embodiments of group A to receive user data from the host; host.

[0139] Embodiment 17: The host of embodiment 16, wherein the cellular network further includes a network node configured to communicate with the UE to transmit user data from the host to the UE.

[0140] Embodiment 18: processing circuitry of the host is configured to execute a host application and thereby provide user data; a host application configured to interact with a client application executing on the UE, the client application being associated with the host application; 18. A host according to embodiment 16 or 17.

[0141] Embodiment 19: A method implemented by a host operating in a communication system further including a network node and a user equipment (UE), the method comprising: Providing user data for the UE; and Initiating a transmission carrying user data to a UE via a cellular network comprising a network node, wherein the UE performs any of the operations recited in any one of the embodiments of group A to receive the user data from the host; and A method comprising:

[0142] Embodiment 20: The method of embodiment 19, further comprising: executing, in the host, a host application associated with the client application running on the UE to receive user data from the UE.

[0143] Embodiment 21: At the host, sending input data to a client application executing on the UE, the input data being provided by the executing host application. further comprising User data is provided by a client application in response to input data from a host application; 21. The method of embodiment 20.

[0144]

[0082] Embodiment 22: A host configured to operate in a communication system for providing over-the-top (OTT) services, the host comprising: processing circuitry configured to provide user data; a network interface configured to initiate transmission of user data to a cellular network for transmission to a user equipment (UE); Equipped with a UE comprising a communications interface and processing circuitry, the communications interface and processing circuitry of the UE configured to perform any of the steps recited in any one of the embodiments of group A to transmit user data to the host; host.

[0145] Embodiment 23: The host of embodiment 22, wherein the cellular network further includes a network node configured to communicate with the UE to transmit user data from the UE to the host.

[0146] Embodiment 24: processing circuitry of the host is configured to execute a host application and thereby provide user data; a host application configured to interact with a client application executing on the UE, the client application being associated with the host application; 24. A host according to embodiment 22 or 23.

[0147] Embodiment 25: A method implemented by a host configured to operate in a communication system further including a network node and a user equipment (UE), the method including receiving, at the host, user data transmitted by the UE to the host via the network node, and the UE performing any of the steps described in any one of the embodiments of Group A to transmit the user data to the host.

[0148] Embodiment 26: The method of embodiment 25, further comprising: executing, in the host, a host application associated with the client application running on the UE to receive user data from the UE.

[0149] Embodiment 27: At the host, sending input data to a client application executing on the UE, the input data being provided by the executing host application. further comprising User data is provided by a client application in response to input data from a host application; 27. The method of embodiment 26.

[0150] Embodiment 28: A host configured to operate in a communication system for providing over-the-top (OTT) services, the host comprising: processing circuitry configured to provide user data; a network interface configured to initiate transmission of user data to a network node in a cellular network for transmission to a user equipment (UE), the network node having a communications interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations recited in any one of the embodiments of Group B to transmit the user data from the host to the UE; and A host.

[0151] Embodiment 29: processing circuitry of the host is configured to execute a host application that provides user data; the UE comprising processing circuitry configured to execute a client application associated with the host application to receive user data transmissions from the host; A host according to embodiment 28.

[0152] Embodiment 30: A method implemented in a host configured to operate in a communication system further including a network node and a user equipment (UE), the method comprising: Providing user data for the UE; and initiating a transmission carrying user data to the UE via a cellular network comprising a network node, the network node performing any of the operations recited in any one of the embodiments of Group B to transmit the user data from the host to the UE; A method comprising:

[0153] Embodiment 31: The method of embodiment 30, further comprising: at the network node, transmitting user data provided by the host for the UE.

[0154] Embodiment 32: A method as described in embodiment 30 or 31, in which user data is provided in the host by executing a host application that interacts with a client application running on the UE, and the client application is associated with the host application.

[0155]

[0082] Embodiment 33: A communication system configured to provide over-the-top services, the communication system comprising: A host is provided, the host processing circuitry configured to provide user data for a user equipment (UE), the user data relating to an over-the-top service; and a network interface configured to initiate transmission of user data towards a cellular network node for transmission to the UE, the network node having a communications interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations recited in any one of the embodiments of Group B to transmit the user data from the host to the UE; and A communication system comprising:

[0156] Embodiment 34: The communication system described in embodiment 33, further comprising a network node and / or user equipment.

[0157]

[0082] Embodiment 35: A host configured to operate in a communication system for providing over-the-top (OTT) services, the host comprising: processing circuitry configured to initiate reception of user data; a network interface configured to receive user data from a network node in a cellular network, the network node having a communications interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations recited in any one of the embodiments of Group B to receive user data from a user equipment (UE) for a host; and A host.

[0158] Embodiment 36: processing circuitry of the host is configured to execute a host application and thereby provide user data; a host application configured to interact with a client application executing on the UE, the client application being associated with the host application; A host according to embodiment 34 or 35.

[0159] Embodiment 37: The host of embodiment 35 or 36, wherein initiating the reception of user data includes requesting the user data.

[0160] Embodiment 38: A method implemented by a host configured to operate in a communication system further including a network node and a user equipment (UE), the method including initiating, at the host, reception of user data from the UE, the user data originating from a transmission received by the network node from the UE, and the network node performing any of the steps described in any one of the embodiments of Group B to receive the user data from the UE for the host.

[0161] Embodiment 39: The method of embodiment 38, further comprising, at the network node, transmitting the received user data to the host.

[0162] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure, and all such improvements and modifications are considered within the scope of the concepts disclosed herein.

Claims

1. 1. A method implemented by a user equipment (UE), the method comprising: receiving (300) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), connecting (302) to a cell served by the second network node; Declaring (304) a radio link failure in the cell served by the second network node; storing (306) information related to the radio link failure in a report in response to declaring (304) the radio link failure in the cell served by the second network node and the indication that the handover is for voice fallback purposes, the information including an indication that a last completed handover for the first network node to the second network node was for voice fallback purposes; A method comprising:

2. 2. The method of claim 1, wherein the first radio access technology is New Radio (NR) and the second radio access technology is Long Term Evolution (LTE).

3. The method of claim 2 , wherein the indication is MobilityFromNR with voice fallback indication.

4. 4. The method of claim 2, wherein the report is a radio link failure report, and wherein storing (306) the information related to the radio link failure comprises storing (306) the information in a VarRLF-Report variable.

5. The method of claim 1 , wherein the report is a radio link failure report.

6. Selecting a cell (308); reconnecting to the cell (308); transmitting (310) said report to a network node associated with said cell; 6. The method of claim 1, further comprising:

7. A user equipment (UE), receiving (300) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), connecting (302) to a cell served by the second network node; Declaring (304) a radio link failure in the cell served by the second network node; storing (306) information related to the radio link failure in a report in response to declaring (304) the radio link failure in the cell served by the second network node and the indication that the handover is for voice fallback purposes, the information including an indication that a last completed handover for the first network node to the second network node was for voice fallback purposes; A user equipment (UE) configured to:

8. 8. The UE of claim 7, further configured to perform the method of any one of claims 2 to 6.

9. A user equipment (UE) (700), a communication interface (712); a processing circuit (702) associated with said communication interface (712); The processing circuit (702) is configured to transmit to the UE (700): receiving (300) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), connecting (302) to a cell served by the second network node; Declaring (304) a radio link failure in the cell served by the second network node; storing (306) information related to the radio link failure in a report in response to declaring (304) the radio link failure in the cell served by the second network node and the indication that the handover is for voice fallback purposes, the information including an indication that a last completed handover for the first network node to the second network node was for voice fallback purposes; A user equipment (UE) (700) configured to:

10. 10. The UE (700) of claim 9, wherein the processing circuitry (702) is further configured to cause the UE (700) to perform a method according to any one of claims 2 to 6.

11. A computer program comprising instructions which, when executed on at least one processor, cause said processor to perform the method of any one of claims 1 to 6.

12. 12. A carrier containing the computer program of claim 11, the carrier being one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium.

13. A non-transitory computer-readable medium comprising instructions executable by processing circuitry of a user equipment (UE), whereby the UE: receiving (300) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), connecting (302) to a cell served by the second network node; Declaring (304) a radio link failure in the cell served by the second network node; storing (306) information related to the radio link failure in a report in response to declaring (304) the radio link failure in the cell served by the second network node and the indication that the handover is for voice fallback purposes, the information including an indication that a last completed handover for the first network node to the second network node was for voice fallback purposes; 1. A non-transitory computer-readable medium operable to:

14. 1. A method implemented by a network node, the method comprising: receiving (500) a radio link failure report from a user equipment (UE), the radio link failure report including an indication that a last completed handover for the UE from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology was for voice fallback purposes; performing one or more actions based on the radio link failure report (502); A method comprising:

15. The method of claim 14 , wherein the one or more actions include sending the radio link failure report to another network node.

16. The method of claim 14 , wherein the one or more actions include sending the radio link failure report to the first network node.

17. 17. The method of claim 14, wherein the first radio access technology is New Radio (NR) and the second radio access technology is Long Term Evolution (LTE).

18. 18. The method of any one of claims 14 to 17, wherein the network node is a base station.

19. a network node, receiving (500) a radio link failure report from a user equipment (UE), the radio link failure report including an indication that a last completed handover for the UE from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology was for voice fallback purposes; performing one or more actions based on the radio link failure report (502); A network node configured to

20. 20. A network node according to claim 19, further configured to perform the method according to any one of claims 15 to 18.

21. A network node (800), a communication interface (806); a processing circuit (802) associated with said communication interface (806); and the processing circuit (802) provides the network node (800) with: receiving (500) a radio link failure report from a user equipment (UE), the radio link failure report including an indication that a last completed handover for the UE from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology was for voice fallback purposes; performing one or more actions based on the radio link failure report (502); A network node (800) configured to:

22. 22. The network node (800) of claim 21, wherein the processing circuitry (802) is further configured to cause the network node (800) to perform a method according to any one of claims 15 to 18.

23. A computer program comprising instructions which, when executed on at least one processor, cause said processor to perform the method of any one of claims 14 to 18.

24. 24. A carrier containing the computer program of claim 23, the carrier being one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium.

25. 1. A non-transitory computer-readable medium comprising instructions executable by processing circuitry of a network node, whereby said network node: receiving (500) a radio link failure report from a user equipment (UE), the radio link failure report including an indication that a last completed handover for the UE from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology was for voice fallback purposes; performing one or more actions based on the radio link failure report (502); 1. A non-transitory computer-readable medium operable to:

26. 1. A method implemented by a user equipment (UE), the method comprising: receiving (400) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), failing (402) to connect to a cell served by the second network node; selecting (404) a cell belonging to the second radio access technology in response to a failure (402) to connect to a cell served by the second network node due to a voice fallback indication being set; connecting to the selected cell (404); Declaring (406) a radio link failure in the selected cell; and in response to declaring (406) the radio link failure in the selected cell and the indication that the handover is for voice fallback purposes, storing (408) information related to the radio link failure in a report, the information including an indication that the cell in which the radio link failure occurred was selected as part of cell reselection due to a voice fallback indication. A method comprising:

27. 27. The method of claim 26, wherein the first radio access technology is New Radio (NR) and the second radio access technology is Long Term Evolution (LTE).

28. 28. The method of claim 27, wherein the voice fallback indication is MobilityFromNR with voice fallback indication.

29. 29. The method of claim 27 or 28, wherein the report is a radio link failure report, and wherein storing (408) the information comprises storing (408) the information in a VarRLF-Report variable.

30. 30. The method of any one of claims 26 to 29, wherein the report is a radio link failure report.

31. Selecting a cell (410); reconnecting to the cell (410); transmitting (412) said report to a network node associated with said cell; 31. The method of any one of claims 26 to 30, further comprising:

32. A user equipment (UE), receiving (400) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), failing (402) to connect to a cell served by the second network node; selecting (404) a cell belonging to the second radio access technology in response to a failure (402) to connect to a cell served by the second network node due to a voice fallback indication being set; connecting to the selected cell (404); Declaring (406) a radio link failure in the selected cell; and in response to declaring (406) the radio link failure in the selected cell and the indication that the handover is for voice fallback purposes, storing (408) information related to the radio link failure in a report, the information including an indication that the cell in which the radio link failure occurred was selected as part of cell reselection due to a voice fallback indication. A user equipment (UE) configured to:

33. 33. The UE of claim 32, further configured to perform the method of any one of claims 27 to 31.

34. A user equipment (UE) (700), a communication interface (712); a processing circuit (702) associated with said communication interface (712); The processing circuit (702) is configured to transmit to the UE (700): receiving (400) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), failing (402) to connect to a cell served by the second network node; selecting (404) a cell belonging to the second radio access technology in response to a failure (402) to connect to a cell served by the second network node due to a voice fallback indication being set; connecting to the selected cell (404); Declaring (406) a radio link failure in the selected cell; and in response to declaring (406) the radio link failure in the selected cell and the indication that the handover is for voice fallback purposes, storing (408) information related to the radio link failure in a report, the information including an indication that the cell in which the radio link failure occurred was selected as part of cell reselection due to a voice fallback indication. A user equipment (UE) (700) configured to:

35. 35. The UE (700) of claim 34, wherein the processing circuitry (702) is further configured to cause the UE (700) to perform a method according to any one of claims 27 to 31.

36. 32. A computer program comprising instructions which, when executed on at least one processor, cause said processor to perform the method of any one of claims 26 to 31.

37. 37. A carrier containing the computer program of claim 36, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium.

38. A non-transitory computer-readable medium comprising instructions executable by processing circuitry of a user equipment (UE), whereby the UE: receiving (400) configuration for performing a handover from a first network node belonging to a first radio access technology to a second network node belonging to a second radio access technology, the configuration including an indication that the handover is for voice fallback purposes; In response to receiving the configuration (300), failing (402) to connect to a cell served by the second network node; selecting (404) a cell belonging to the second radio access technology in response to a failure (402) to connect to a cell served by the second network node due to a voice fallback indication being set; connecting to the selected cell (404); Declaring (406) a radio link failure in the selected cell; and in response to declaring (406) the radio link failure in the selected cell and the indication that the handover is for voice fallback purposes, storing (408) information related to the radio link failure in a report, the information including an indication that the cell in which the radio link failure occurred was selected as part of cell reselection due to a voice fallback indication.

1. A non-transitory computer-readable medium operable to:

39. 1. A method implemented by a network node, the method comprising: receiving (500) a radio link failure report from a user equipment (UE) including an indication that a cell where a radio link failure occurred has been selected as part of cell reselection with a voice fallback indication; performing one or more actions based on the radio link failure report (502); A method comprising:

40. The method of claim 14 , wherein the one or more actions include sending the radio link failure report to another network node.

41. 41. The method of claim 39 or 40, wherein the network node is a base station.

42. A network node (800), receiving (500) a radio link failure report from a user equipment (UE) including an indication that a cell where a radio link failure occurred has been selected as part of cell reselection with a voice fallback indication; performing one or more actions based on the radio link failure report (502); A network node (800) configured to:

43. A network node (800) according to claim 42, further configured to perform the method according to claim 40 or 41.

44. A network node (800), a communication interface (806); a processing circuit (802) associated with said communication interface (806); and the processing circuit (802) provides the network node (800) with: receiving (500) a radio link failure report from a user equipment (UE) including an indication that a cell where a radio link failure occurred has been selected as part of cell reselection with a voice fallback indication; performing one or more actions based on the radio link failure report (502); A network node (800) configured to:

45. 45. The network node (800) of claim 44, wherein the processing circuitry (802) is further configured to cause the network node (800) to perform a method according to claim 40 or 41.

46. 42. A computer program comprising instructions which, when executed on at least one processor, cause said processor to perform the method of any one of claims 39 to 41.

47. 47. A carrier containing the computer program of claim 46, the carrier being one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium.

48. 1. A non-transitory computer-readable medium comprising instructions executable by processing circuitry of a network node, whereby said network node: receiving (500) a radio link failure report from a user equipment (UE) including an indication that a cell where a radio link failure occurred has been selected as part of cell reselection with a voice fallback indication; performing one or more actions based on the radio link failure report (502); 1. A non-transitory computer-readable medium operable to:

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