Early real-time radio link problem detection

Abstract

A component (500) of a cellular user equipment (UE) device (102) is configured to detect adverse radio link conditions. The component (500) monitors a plurality of layers (610) of a communication stack (608) of the UE device (102) during an active voice call (701). In response to monitoring the plurality of layers (610), the component (500) detects at least one adverse radio link condition associated with the active voice call (701). In response to detecting the at least one adverse radio link condition, the component provides a radio link degradation indication (622) to a second component (604) of the UE device (102).

Description

[Background technology]

[0001] background In cellular-based networks, communication link failures can occur for a variety of reasons, including signal or transmit power problems, internal errors, and the like. When a radio link fails or is severed during an active voice call, there can be a delay between the link failure and the recognition of the failure by an application on the wireless communication device. This delay is typically caused by independent components in various communication stack layers detecting the link failure and, in some cases, can prevent the wireless communication device from recovering the voice call or result in a degraded user experience, such as a loss of connectivity. Summary of the Invention

[0002] Overview of the embodiment According to one aspect, a method performed on a first component of a cellular user equipment (UE) device for detecting adverse radio link conditions includes monitoring multiple layers of a communication stack of the UE device during an active voice call. In response to monitoring the multiple layers, at least one adverse radio link condition associated with the active voice call is detected. A radio link degradation (RLD) is provided to a second component of the UE device in response to detecting the at least one adverse radio link condition.

[0003] In at least some embodiments, monitoring multiple layers of a communication stack of the UE device during an active voice call includes monitoring at least one parameter across one or more of the multiple layers, the at least one parameter being associated with maintaining the active voice call. At least one adverse radio link condition associated with the active voice call can be detected based on the at least one monitored parameter. In some examples, the at least one adverse radio link condition can be detected based on (or in response to) the at least one monitored parameter satisfying one or more predetermined criteria. The criteria can be indicative of quality of the active voice call.

[0004] Optionally, in some demonstrative embodiments, monitoring at least one parameter across one or more of the multiple layers includes monitoring multiple parameters across the multiple layers, the multiple parameters being associated with maintaining an active voice call. At least one adverse radio link condition associated with the active voice call may be detected based on one or more of the monitored multiple parameters. In some examples, the at least one adverse radio link condition may be detected based on (or in response to) one or more of the monitored multiple parameters satisfying one or more predetermined criteria. The criteria may be indicative of quality of the active voice call.

[0005] In at least some embodiments, the RLD indication notifies the second component that at least one adverse radio link condition exists and identifies a cause of the at least one adverse radio link condition. In at least some embodiments, providing the RLD indication includes providing the RLD indication to the second component during an active voice call.

[0006] In at least some embodiments, detecting at least one adverse wireless link condition includes detecting a signal strength update in response to multiple layers of monitoring. The signal strength update is an example of a monitored parameter. In response to detecting the signal strength update, one or more signal-related characteristics associated with the signal strength update are accessed. A determination is made whether a value associated with any of the one or more signal-related characteristics satisfies a corresponding threshold. In response to the value associated with any of the one or more signal-related characteristics satisfying a corresponding threshold, a determination is made that at least one adverse wireless link condition exists.

[0007] In at least some embodiments, the method further includes determining whether transmission time interval (TTI) bundling is enabled at the UE device. In response to TTI bundling being enabled, a corresponding threshold is selected from a first threshold set. In response to TTI bundling being disabled, a corresponding threshold is selected from a second threshold set. The second threshold set is set lower than the first threshold set.

[0008] In at least some embodiments, the at least one adverse radio link condition detected is an out-of-sync condition, and providing the RLD indication includes determining that a radio link failure (RLF) timer has been started in response to the out-of-sync condition. The out-of-sync condition is an example of a monitored parameter. The RLD indication is provided to the second component upon starting the RLF timer and before the RLF timer expires.

[0009] In at least some embodiments, the method further includes resetting an RLD indication maintained internally by the first component in response to detecting one of the following: a synchronization condition occurring while the RLF timer was active, expiration of the RLF timer, or expiration of the RLF timer and the UE device successfully performing a radio resource control (RRC) connection re-establishment procedure.

[0010] In at least some embodiments, the at least one detected adverse radio link condition is an out-of-sync condition. The method further includes determining that an RLF timer has expired and that the RLF timer was started in response to the occurrence of the out-of-sync condition (903). In response to the RLF timer expiring, determining that the UE device has successfully performed an RRC connection re-establishment procedure. In response to the RLF timer expiring, resetting an RLD indication maintained internally by the first component in response to the RRC connection re-establishment procedure being successful.

[0011] In at least some embodiments, the at least one detected adverse radio link condition is a radio link control (RLC) maximum retransmission condition associated with the data traffic, and providing the RLD indication includes determining that the RLC maximum retransmission condition resulted in the RLF. The RLC maximum retransmission condition is an example of a monitored parameter. In response to the RLF, the RLD indication is provided to a second component. In at least some embodiments, a determination is made that the UE device has successfully completed an RRC connection re-establishment procedure in response to the RLF. In response to the successful completion of the RRC connection re-establishment procedure, it is determined whether another adverse radio link condition exists. In response to the at least one other adverse radio link condition, an updated RLD indication is provided to the second component indicating that at least one other adverse radio link condition exists and that the RLC maximum retransmission condition no longer exists. In response to the absence of other adverse radio link conditions, an RLD indication maintained internally by the first component is reset.

[0012] In at least some embodiments, detecting at least one adverse radio link condition includes determining a required bandwidth at a first layer of the plurality of layers for current voice traffic on a downlink channel associated with the active voice call. A current throughput at a second layer of the plurality of layers is determined. The current throughput is for a dedicated voice radio bearer associated with the active voice call. A low-performance condition is determined to exist at the first layer in response to the required bandwidth being greater than the current throughput. The low-performance condition is an example of a monitored parameter. In at least some embodiments, detecting at least one adverse radio link condition further includes incrementing a low-performance count in response to determining that a low-performance condition exists. The low-performance count is compared to a low-performance count threshold. An RLD indication is provided to the second component in response to the low-performance count satisfying the low-performance count threshold. In at least some embodiments, an RLD indication internally maintained by the first component, indicating the existence of at least one adverse radio link condition, is reset in response to the low-performance count not satisfying the low-performance count threshold.

[0013] In at least some embodiments, detecting at least one adverse radio link condition includes determining a required bandwidth for outgoing voice traffic associated with an active voice call on a first layer of the plurality of layers, determining a currently achieved throughput on a second layer of the plurality of layers on an uplink channel associated with the active voice call, and determining that a poor performance condition exists on the second layer in response to the required bandwidth being greater than the currently achieved throughput.

[0014] In at least some embodiments, detecting the at least one adverse radio link condition further includes incrementing a low functionality count in response to determining that the low functionality condition exists. The low functionality count is compared to a low functionality count threshold. The RLD indication is provided to the second component in response to the low functionality count satisfying the low functionality count threshold. In at least some embodiments, the RLD indication, maintained internally by the first component and indicating that the at least one adverse radio link condition exists, is reset in response to the low functionality count not satisfying the low functionality count threshold.

[0015] In at least one embodiment, detecting at least one adverse radio link condition includes determining that a high transmit power deficiency condition exists. The high transmit power deficiency condition is an example of a monitored parameter. A determination is made that a throughput of outgoing voice packets at a first layer of the plurality of layers is less than a throughput of voice traffic generated at a second layer of the plurality of layers. In at least some embodiments, determining that a high transmit power deficiency condition exists includes detecting a transmit power deficiency and comparing the transmit power deficiency to a transmit power deficiency threshold. The high transmit power deficiency count is incremented in response to the transmit power deficiency satisfying the incremented transmit power deficiency threshold. For a monitoring window of a given number of transmission instances, a proportion of high transmit power deficiency instances is determined based on the high transmit power deficiency count. A determination of whether a high transmit power deficiency condition exists is made as a function of the proportion of high transmit power deficiency instances that satisfy the proportion threshold.

[0016] According to another aspect, a user equipment device includes one or more radio frequency (RF) modems configured to wirelessly communicate with at least one network. One or more processors are coupled to the one or more RF modems. At least one memory has executable instructions stored therein. The executable instructions are configured to operate at least one of the one or more processors or the one or more RF modems to perform any of the method operations described herein.

[0017] According to yet another aspect, a computer-readable storage medium embodies a set of executable instructions for operating a computer system to perform any of the method acts described herein.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings, in which: The use of the same reference symbols in different drawings indicates similar or identical items.

[0019] The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings, in which: The use of the same reference symbols in different drawings indicates similar or identical items. [Brief explanation of the drawings]

[0020] [Figure 1] 1 illustrates an exemplary wireless communication system employing user equipment (UE) devices that implement one or more detection mechanisms for adverse radio link conditions, according to some embodiments. [Figure 2] 2 is a block diagram illustrating an exemplary mode of a detection mechanism for adverse radio link conditions used by the UE device of FIG. 1, according to some embodiments. [Figure 3] 1 illustrates an example configuration of a UE device that implements one or more detection mechanisms for adverse radio link conditions, according to some embodiments. [Figure 4] 1 illustrates an exemplary configuration of a system-on-chip (SoC) implementing one or more detection mechanisms for adverse wireless link conditions, according to some embodiments. [Figure 5] FIG. 1 illustrates an exemplary configuration of a communications processor that implements one or more detection mechanisms for adverse wireless link conditions, according to some embodiments. [Figure 6] FIG. 2 illustrates an exemplary functional configuration of a communications processor that implements one or more detection mechanisms for adverse wireless link conditions, according to some embodiments. [Figure 7] 1A-1D together illustrate an exemplary operational diagram for implementing detection of adverse radio link conditions in a UE device based on low signal strength, according to some embodiments. [Figure 8] 1A-1D together illustrate an exemplary operational diagram for implementing detection of adverse radio link conditions in a UE device based on low signal strength, according to some embodiments. [Figure 9] 1 illustrates example operations for implementing adverse radio link condition detection in a UE device based on radio link failure caused by out-of-synchronization, according to some embodiments. [Figure 10] 1 illustrates example operations for implementing adverse radio link condition detection in a UE device based on maximum retransmission induced radio link failure, according to some embodiments. [Figure 11] 1 illustrates example operations for implementing adverse radio link condition detection in a UE device based on poor physical layer capabilities on a downlink channel, according to some embodiments. [Figure 12] 1 illustrates example operations for implementing adverse radio link condition detection in a UE device based on poor physical layer capabilities on an uplink channel, according to some embodiments. [Figure 13] 1 illustrates example operations for implementing detection of adverse radio link conditions in a UE device based on insufficient transmit power, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0021] Detailed Description Components within a user equipment (UE) device typically share limited radio link information. By limiting or delaying the sharing of radio link information, components can conserve power, avoid unnecessary disruptions to applications, and so on. However, limiting or delaying radio link information related to an active voice call can cause various operational and user experience problems. For example, if a component such as an application processor receives delayed or limited information about a harmful radio link for an active voice call, the application processor may miss an opportunity to preserve the call by taking appropriate action, such as switching to Voice over Wireless-Fidelity (VoWiFi). Additionally, the UE device may unnecessarily use computer resources by keeping the call open and displaying on the UE device's user interface that the call is connected despite the radio link failure, resulting in a poor user experience.

[0022] Accordingly, the following describes embodiments of systems and methods for configuring at least one component of a UE device to actively detect and report adverse radio link conditions associated with voice traffic in real time. For example, the UE device component is configured to monitor, analyze, and report voice call-related information, such as radio link information that has caused or may cause a voice call drop or a poor voice experience. Examples of such radio link information include low signal, radio link failure (RLF), etc. In at least some embodiments, the configured UE component collects information across various network protocol stack layers, for example, within a communications processor. The configured UE component monitors and processes key factors (or parameters) related to maintaining a voice call connection at an acceptable quality. For example, the UE component monitors one or more parameters across at least one network protocol stack layer, one or more parameters related to maintaining an active voice call (particularly, related to maintaining an active voice call at a quality above a quality threshold). By monitoring and analyzing key factors across network protocol stack layers, the configured UE component can detect radio link issues in real time or near real time with improved accuracy over traditional radio link failure mechanisms. Upon detecting a radio link failure (or potential failure), the configured UE component notifies another UE component, such as an application processor, so that appropriate action can be taken to mitigate operational and resource issues, and user experience issues, caused by the radio link failure or impending failure.

[0023] For ease of explanation, the following techniques are described in the example context of one or more UE devices and a radio access network (RAN) implementing one or more radio access technologies (RATs), including at least the fifth-generation (5G) New Radio (NR) standard (e.g., Third Generation Partnership Project (3GPP®) Release 15, 3GPP Release 16, etc.) (hereinafter, "5GNR" or "5GNR standard"). However, it should be understood that the present disclosure is not limited to networks employing a 5G NR RAT configuration; rather, the techniques described herein may be applied to any combination of different RATs employed by a UE device and a RAN. It should also be understood that the present disclosure is not limited to the specific network configuration or architecture described herein for implementing radio link failure detection in a UE device. Instead, the techniques described herein may be applied to any configuration of a RAN. Also, the present disclosure is not limited to the examples and situations described herein; rather, the techniques described herein may be applied to any network environment in which a UE device implements techniques for detecting adverse radio link conditions.

[0024] 1 illustrates a mobile cellular network (system) 100 according to at least some embodiments. As shown, the mobile cellular network 100 includes a user equipment (UE) device 102 configured to communicate with one or more base stations 104 (base stations 104-1 and 104-2) over one or more wireless communication links 106 (wireless links 106-1 and 106-2). In at least some embodiments, the UE device 102 includes any of a variety of wireless communication devices, such as a mobile phone, a cellular-enabled tablet computer or notebook computer, a cellular-enabled wearable device, an automobile, or other vehicle that utilizes cellular services (e.g., navigation, entertainment service provision, in-car mobile hotspot, etc.). In at least some embodiments, the UE device 102 uses a single RAT 108. In other embodiments, the UE device 102 is a multi-mode UE device that uses multiple RATs 108. Examples of multiple RATs include 3GPP Long Term Evolution (3GPP LTE) RAT 108-1 and 3GPP Fifth Generation New Radio (5GNR) RAT 108-2.

[0025] In at least some embodiments, the base station 104 is implemented as a macro cell, a micro cell, a small cell, a pico cell, etc., or any combination thereof. Examples of base stations 104 include an Evolved Universal Terrestrial Radio Access Network Node B (E-UTRAN Node B), an Evolved Node B (eNodeB or eNB), a Next Generation (NG or NGEN) Node B (gNodeB or gNB), etc. The base station 104 communicates with the UE device 102 over a radio link 106 implemented using any suitable type of radio link. In at least some embodiments, the radio link 106 includes a downlink of data and control information communicated from the base station 104 to the UE device 102, an uplink of data and control information communicated from the UE device 102 to the base station 104, or both. The radio link 106 (or bearer), in at least some embodiments, is implemented using any suitable communication protocol or standard, or combination of communication protocols or standards, such as 3GPP 4G LTE, 5G NR, etc. In at least some embodiments, multiple radio links 106 are aggregated into carrier aggregation to provide higher data rates to the UE device 102. Additionally, multiple radio links 106 from multiple base stations 104 are, in at least some embodiments, configured for coordinated multipoint (CoMP) communication and dual connectivity with the UE device 102, such as single-RAT LTE-LTE or NR-NR dual connectivity, or multi-radio access technology (Multi-RAT) dual connectivity (MR-DC), including E-UTRA-NR dual connectivity (EN-DC), NGEN radio access network (RAN) E-UTRA-NR dual connectivity (NGEN-DC), and N-E-UTRA dual connectivity (NE-DC).

[0026] The base stations 104 collectively form a radio access network 110, such as an E-UTRAN or 5G NRRAN. The base stations 104 are connected to a core network 112 via one or more links 114 (links 114-1 and 114-2) through control plane and user plane interfaces. Depending on the configuration of the mobile cellular network 100, the core network 112 is either an evolved packet core (EPC) network 112-1 or a 5G core network (5GC) 112-2. For example, in an E-UTRAN configuration or a 5G non-standalone (NSA) EN-DC configuration, the core network 112 is an EPC network 112-1 that includes, for example, a mobility management entity (MME) 116 and a serving gateway (S-GW) 118. The MME 116 provides control plane functions, such as registration and authentication, authorization, and mobility management, for multiple UE devices 102. The S-GW 118 relays user plane data between the UE device 102 and an external network 120 (e.g., the Internet) and one or more remote services 122. In a 5G Standalone (SA) configuration or an NSANE-DC or NGEN-DC configuration, the core network 112 is a 5GC network 112-2. The 5GC 112-2 includes, for example, an Access and Mobility Management Function (AMF) 124 and a User Plane Function (UPF) 126. The AMF 124 provides control plane functions such as registration and authentication, authorization, and mobility management for multiple UEs 102. The UPF 126 relays user plane data between the UE 102 and the external network 120 (e.g., the Internet) and one or more remote services 122.

[0027] In at least some embodiments, when the UE device 102 uses EN-DC, the UE device 102 communicates with a first base station 104-1 implementing 4G LTERAT, e.g., functioning as a master node (MN), and the radio link 106-1 is an E-UTRA link. The UE device 102 also communicates with a second base station 104-2 implementing 5G NRRAT, e.g., functioning as a secondary node (SN), and the radio link 106-2 is a 5G NR link. In link 128, the first base station (e.g., eNB) 104-1 and the second base station (e.g., 5G NR) 104-2 communicate user plane and control plane data, e.g., via an X2 interface. The first base station 104-1 communicates control plane information with the MME 116 in the EPC 112-1, e.g., via an S1-MME interface, and relays the control plane information to the second base station 104-2, e.g., via an X2 interface.

[0028] User plane (UP) data is transmitted between the EPC network 112-1 and the UE device 102 using a data radio bearer (DRB). Examples of DRBs in the EN-DC include a master cell group (MCG) bearer, a secondary cell group (SCG) bearer, and a split bearer. An MCG bearer is a direct DRB that terminates at the MN (e.g., the first base station 104-1) and uses only the MN's lower layers (Radio Link Control (RLC), Medium Access Layer (MAC), and Physical Layer (PHY)). When an MCG bearer is used, the MN receives data from the EPC network 112-1 and transmits the data to the UE device 102. An SCG bearer is a direct DRB that terminates at the SN (e.g., the second base station 104-2) and uses only the SN's lower layers (RLC, MAC, and PHY).

[0029] When an SCG bearer is used, the SN receives data from the EPC network 112-1 and transmits the data to the UE device 102. The split bearer is either an MCG split bearer or an SCG split bearer. An MCG split bearer is a DRB that terminates at the MCG and uses either or both of the MN and SN lower layers. When an MCG split bearer is used, the MN receives data from the EPC network 112-1 and splits the data into two parts. One part of the data is sent from the MN to the UE device 102, and the second part of the data is sent from the SN to the UE device 102. An SCG split bearer is a DRB that terminates at the SN and uses either or both of the MN and SN lower layers. When an SCG split bearer is used, the SN receives data from the EPC network 112-1 and splits the data into two parts. One part of the data is sent from the SN to the UE device 102, and the second part of the data is sent from the MN to the UE device 102.

[0030] In another embodiment, when the UE device 102 uses NGEN-DC, the UE device 102 communicates with a first base station 104-1 functioning as a mobile node (MN), and the radio link 106-1 is an E-UTRA link. The UE device 102 also communicates with a second base station 104-2 functioning as a 5G NR link, and the radio link 106-2 is a 5G NR link. In link 128, the first base station 104-1 and the second base station 104-2 communicate user plane and control plane data, for example, via an Xn interface. The first base station 104-1 communicates control plane information with the AMF 124 in the 5GC network 112-2, for example, via an NG-C interface, and relays the control plane information to the second base station 104-2, for example, via the Xn interface.

[0031] In a further embodiment, when the UE device 102 uses NE-DC, the UE device 102 communicates with a second base station 104-2 functioning as a mobile node, and the radio link 106-1 is a 5G NR link. The UE device 102 also communicates with a first base station 104-1 functioning as a system node, and the radio link 106-1 is an E-UTRA link. On link 128, the first base station 104-1 and the second base station 104-2 communicate user plane data and control plane data, for example, via an Xn interface. The second base station 104-2 communicates control plane information with the AMF 124 in the 5GC network 112-2, for example, via an NG-C interface, and relays the control plane information to the first base station 104-1, for example, via the Xn interface.

[0032] 1 represents a single RATDC configuration. In one type of single RATDC situation, both base stations 104-1 and 104-2 are E-UTRA base stations, e.g., communicating user plane and control plane data via an X2 interface on link 128, and both base stations 104-1 and 104-2 link to an EPC 112-1. In another type of single RATDC configuration, both base stations 104-1 and 104-2 are 5GNR base stations, e.g., communicating user plane and control plane data via an Xn interface on link 128, and both base station stations 104-1 and 104-2 link to a 5GC network 112-2.

[0033] During operation of a voice call, the UE device 102 may encounter adverse radio link conditions that may result in, or potentially cause, a radio link failure or degradation of voice quality. The quality of the voice call may fall below a predetermined quality threshold due to poor radio link conditions or may be completely disconnected / lost from the UE device 102. Accordingly, in at least some embodiments, the UE device 102 uses one or more adverse radio link condition (ARLC) detection mechanisms 130 to detect adverse radio link conditions and radio link failures associated with an active voice call in real time or near real time. As described in further detail below, the ARLC detection mechanism 130 includes one or more modes of actively detecting adverse radio link conditions associated with voice traffic (e.g., based on one or more monitored parameters related to call maintenance) and providing real-time feedback regarding the cause of a radio link failure or potential failure. In some examples, at least one adverse radio link condition may be detected based on one or more monitored parameters that meet one or more predetermined criteria that may be indicative of (or related to) the quality of the voice call. Monitoring the radio link condition and providing real-time or near-real-time feedback improves the user experience during voice calls. For example, providing timely insight into the voice call connection keeps the user informed of the current link condition and avoids frustrating scenarios. Additionally, the various detection modes employed by the ARLC detection mechanism 130 provide early reporting of radio link problems to one or more components of the UE device 102. Early reporting of adverse link conditions allows a component of the UE device 102, such as an application processor, to take one or more actions to preserve the call, such as switching an active call to VoWiFi. Resource utilization may therefore be improved.

[0034] 2 illustrates various example modes that may be used alone or in various combinations by the UE device 102 as part of the ARLC detection mechanism 130, according to some embodiments. Each of these modes is described in more detail below with reference to FIGS. 7 through 13. These modes may be provided individually, or one or more modes may be provided in any suitable combination as part of the ARLC detection mechanism 130.

[0035] One such mode includes a first ARLC detection mode 202. In this mode, the ARLC detection mechanism 130 monitors for low signal conditions by determining the signal strength of a 4G LTE, 5G NR signal or beam, or a combination thereof, based on one or more signal-related characteristics / parameters. Examples of signal-related characteristics include reference signal received power (RSRP), reference signal received quality (RSRQ), carrier-to-interference-plus-noise ratio (CINR), signal-to-interference-plus-noise ratio (SINR), etc. The ARLC detection mechanism 130 determines that an adverse radio link condition exists during an active voice call if the signal strength associated with the call falls below a threshold. In other words, in this example, the ARLC detection mechanism 130 detects an adverse radio link condition based on the monitored parameter of signal strength. In response, the ARLC detection mechanism 130 reports a radio link degradation (RLD) indication to inform one or more other components of the UE device 102 of the detected adverse radio link condition. In at least some embodiments, the possible cause of the RLD, such as a low signal condition, is also transmitted to other components of the UE device 102 .

[0036] Another mode includes a second ARLC detection mode 204. In this mode, the ARLC detection mechanism 130 monitors for radio link failure (RLF) due to an out-of-sync condition or a radio link control (RLC) maximum (max) retransmission condition. However, unlike the out-of-sync or max retransmission RLF defined in the 3GPP specifications, the second ARLC detection mode 204 of at least some embodiments provides flexibility in assessing the impact of RLD on voice traffic and quality. In other words, in at least some embodiments, the second ARLC detection mode 204 is voice call oriented, and the ARLC detection mechanism 130 reports RLD based on how it impacts the voice call. For example, during an active voice call, the ARLC detection mechanism 130 monitors out-of-sync indications generated by one or more protocol stack layers. In at least some embodiments, the ARLC detection mechanism 130 can monitor across one or more (network) protocol stack layers for generated out-of-sync indications / conditions (or parameters). In at least some embodiments, the out-of-sync indication identifies the number of intervals during which the UE device 102 failed to successfully decode the physical downlink control channel (PDCCH). One example of an out-of-sync indication is the N310 indication defined in the 3GPP standards for 4G LTE and 5G NR. When a threshold number of consecutive out-of-sync indications are detected, the ARLC detection mechanism 130 starts a timer, such as the network-configured T310 timer defined in the 3GPP standards for 4G LTE and 5G NR. If the timer expires or if a threshold number of consecutive in-sync indications are not received while the timer is running, the ARLC detection mechanism 130 determines that a radio link failure has occurred due to an out-of-sync condition. In other words, in this example, the ARLC detection mechanism 130 detects adverse radio link conditions based on monitored parameters of the out-of-sync condition. One example of an in-sync indication is the N311 indication defined in the 3GPP standards for 4G LTE and 5G NR. In response, the ARLC detection mechanism 130 reports an RLD indication to inform one or more other components of the UE device 102 of the detected adverse radio link condition, such as a radio link failure.In at least some embodiments, the possible cause of the radio link failure, such as an out-of-sync condition, is also transmitted to other components of the UE device 102 .

[0037] When monitoring the RLC maximum retransmission condition, the ARLC detection mechanism 130 monitors the number of RLC retransmission attempts during data traffic in RLC acknowledged mode (AM). If the number of RLC retransmission attempts exceeds a threshold number, the ARLC detection mechanism 130 determines that the RLC maximum retransmission condition has occurred. The ARLC detection mechanism 130 transmits an RLD indication to inform one or more other components of the UE device 102 of a detected adverse radio link condition, such as a radio link failure. In at least some embodiments, a possible cause of the radio link failure, such as the RLC maximum retransmission condition, is also transmitted to the other components of the UE device 102.

[0038] Yet another mode includes a third ARLC detection mode 206 in which the ARLC detection mechanism 130 monitors physical (PHY) layer capabilities. In this mode, the ARLC detection mechanism 130 monitors downlink (DL) PHY layer and uplink (UL) PHY layer capabilities. In at least some embodiments, capabilities refer to the UE device 102's expected throughput based on the radio resources allocated by the cellular network 100 and the current block error rate (BLER). If either the DL or UL capabilities of voice traffic fall below a threshold, the ARLC detection mechanism 130 generates an RLD indication to notify one or more other components of the UE device 102 of the detected adverse radio link condition. In other words, the ARLC detection mechanism 130 detects the adverse radio link condition based on the monitored capability parameters, in this example. In at least some embodiments, a possible cause of the RLD, such as low DL or UL capabilities, is also transmitted to other components of the UE device 102.

[0039] Additional modes include a fourth ARLC detection mode 208 in which the ARLC detection mechanism 130 monitors the transmit (Tx) power deficiency in the UE device 102. A Tx power deficiency occurs when the actual Tx power is not equal to the target Tx power. This is typically caused by a maximum transmit power level (MTPL) upper limit or an internal error. As a result, the actual applied Tx power is lower than the MTPL. If the Tx power deficiency is large and persistent (e.g., throughput at one or more layers may be reduced), the Tx power deficiency affects UL packet transmission. If many voice packets are lost, an active voice call may be dropped or at least voice quality may be degraded. If path loss is large, the target Tx power may be higher, increasing the Tx deficiency. Therefore, when the ARLC detection mechanism 130 detects a Tx deficiency that exceeds a threshold, the ARLC detection mechanism 130 generates an RLD indication to notify one or more other components of the UE device 102 of the detected adverse radio link conditions. In other words, the ARLC detection mechanism 130 detects adverse radio link conditions based on the monitored parameter of, in this example, transmit power insufficiency. In at least some embodiments, the possible causes of the RLD, such as Tx power insufficiency, are also transmitted to other components of the UE device 102. In this mode, the ARLC detection mechanism 130, in at least some embodiments, also monitors protocol data unit (PDU) flows in dedicated voice radio bearers to more accurately estimate the impact of Tx power insufficiency on voice traffic.

[0040] FIG. 3 illustrates an example apparatus diagram 300 of a UE device 102. In at least some embodiments, the apparatus diagram 300 illustrates a UE device implementing various aspects of detecting adverse radio link conditions for a voice call in real time or near real time. The UE device 102 may include additional functionality and interfaces that are omitted from FIG. 3 for clarity. In at least some embodiments, the UE device 102 includes an antenna 302, a radio frequency (RF) front end 304, and one or more RF transceivers 306 (e.g., a 3GPP 4G LTE transceiver 306-1 and a 5G NR transceiver 306-2) for communicating with one or more base stations 104 in a RAN 110, such as a 5G RAN, an E-UTRAN, or a combination thereof. In at least some embodiments, the RF front end 304 includes a transmit (Tx) front end 304-1 and a receive (Rx) front end 304-2. The Tx front end 304-1 includes components such as one or more power amplifiers (PAs), drivers, mixers, filters, etc. The Rx front end 304-2 includes components such as a low noise amplifier (LNA), a mixer, a filter, etc. In at least some embodiments, the RF front end 304 couples or connects one or more transceivers 306, such as an LTE transceiver 306-1 and a 5G NR transceiver 306-2, to the antenna 302 to facilitate various types of wireless communications.

[0041] In at least some embodiments, the antenna 302 of the UE device 102 includes an array of multiple antennas that may be similarly configured or different from one another. In at least some embodiments, the antenna 302 and RF front end 304 are tuned or tunable to one or more frequency bands, such as frequency bands defined by 3GPP LTE, 3GPP 5G NR, IEEE Wireless Local Area Network (WLAN), IEEE Wireless Metropolitan Area Network (WMAN), or other communications standards. In at least some embodiments, the antenna 302, RF front end 304, LTE transceiver 306-1, and 5G NR transceiver 306-2 are configured to support beamforming (e.g., analog, digital, hybrid) or in-phase and quadrature (I / Q) operations (e.g., I / Q modulation or demodulation operations) to transmit and receive communications with one or more base stations 104. By way of example, the antenna 302 and RF front end 304 may operate in sub-gigahertz bands, sub-6 GHz bands, above 6 GHz bands, or a combination of these bands defined by 3GPP LTE, 3GPP 5G NR, or other communications standards.

[0042] In at least some embodiments, the antenna 302 includes one or more receive antennas arranged in a one-dimensional shape (e.g., a line) or two-dimensional shape (e.g., a triangle, a rectangle, or an L-shape) for implementation, which include three or more receive antenna elements. A one-dimensional shape allows for measurement of one angular dimension (e.g., azimuth or elevation), while a two-dimensional shape allows for measurement of two angular dimensions (e.g., both azimuth and elevation). Using at least a portion of the antenna 302, the UE device 102 can form beams that are steered or unsteered, wide or narrow, or shaped (e.g., hemispherical, cubic, sector-shaped, conical, or cylindrical). One or more transmit antennas may have an unsteered omnidirectional radiation pattern or may generate steerable wide beams. Any of these techniques allows the UE device 102 to transmit wireless signals to illuminate a large volume. In some embodiments, the receive antenna generates thousands of narrow steered beams (e.g., 2000 beams, 4000 beams, or 6000 beams) through digital beamforming to achieve the desired level of angular accuracy and resolution.

[0043] In at least some embodiments, the UE device 102 includes one or more sensors 308 implemented to detect various characteristics such as one or more of temperature, power supply, power usage, battery status, etc. Examples of sensors include thermal sensors, battery sensors, power usage sensors, etc.

[0044] The UE device 102 also includes at least one processor 310. The processor 310, in at least some embodiments, is a single-core processor or a multi-core processor constructed from various materials, such as silicon, polysilicon, high-K dielectrics, copper, etc. In at least some embodiments, the processor 310 is implemented at least in part in hardware, including, for example, an integrated circuit or system-on-chip (SoC), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), components of a complex programmable logic device (CPLD), other implementations in silicon or other hardware, or a combination thereof.

[0045] Examples of the processor 310 include a communications processor, an application processor, a microprocessor, a DSP, a controller, etc. The communications processor, in at least some embodiments, is implemented as a modem baseband processor, a software defined radio module, a configurable modem (e.g., a multi-mode, multi-band modem), a wireless data interface, a wireless modem, etc. In at least some embodiments, the communications processor supports one or more of wireless network data access, messaging, or database services, as well as various voice-based communications (e.g., voice calls). The application processor, in at least some embodiments, provides computing resources to applications executing on the UE device 102. For example, the applications provide a self-contained operating environment that provides system functions (e.g., graphics processing, memory management, and multimedia processing) to support applications executing on the UE device 102.

[0046] The UE device 102 further includes a non-transitory computer-readable storage medium 312 (CRM 312). Computer-readable storage media as described herein do not include propagated signals. In at least some embodiments, the CRM 312 includes any suitable memory or storage device, such as random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or flash memory that can be used to store device data 314 of the UE device 102. In at least some embodiments, the device data 314 includes user data, multimedia data, beamforming codebooks, applications 316, a user interface 318, an operating system of the UE device 102, etc., that are executable by the processor 310 to enable user plane communications, control plane signaling, and user interaction with the UE device 102. The user interface 318, in at least one embodiment, is configured to receive input from a user of the UE device 102, for example, to receive input from the user that defines and / or facilitates one or more aspects of adverse radio link condition detection. In at least some embodiments, the user interface 318 includes a graphical user interface (GUI) that receives input information via touch input. In other examples, the user interface 318 includes an intelligent assistant that receives input information via audible input or voice. Alternatively, or additionally, the operating system of the UE device 102 is maintained as firmware or an application on the CRM 312 and executed by the processor 310.

[0047] The CRM 312, in at least some embodiments, also includes one or both of a communications manager 320 and an ARLC monitoring module 322. Alternatively, or additionally, one or both of the communications manager 320 and the ARLC monitoring module 322, in at least some embodiments, are integrated with other components of the UE device 102 or are implemented in whole or in part as separate hardware logic or circuitry. In at least some embodiments, the communications manager 320 configures the RF front end 304, the LTE transceiver (modem) 306-1, the 5G NR transceiver (modem) 306-2, or a combination thereof, to perform one or more wireless communication operations.

[0048] The ARLC monitoring module 322, in at least some embodiments, implements the ARLC detection mechanism 130 for detecting adverse radio link conditions and radio link failures in real time or near real time. For example, the ARLC monitoring module 322 is configured to perform one or more of low-signal-based ARLC detection 202, RLF-based ARLC detection 204, PHY layer capability-based ARLC detection 206, and transmit power shortage-based ARLC detection 208. As described in more detail below, in at least some embodiments, the ARLC monitoring module 322 performs ARLC monitoring by collecting information across various network protocol stack layers within the one or more processors 310 of the UE device 102. This information represents factors or parameters related to maintaining a voice call connection with acceptable quality. By analyzing key elements across the network protocol stack layers, the configured UE components detect radio link issues in real time or near real time with improved accuracy over traditional radio link failure mechanisms. Upon detecting a radio link failure (or potential failure), the configured UE component notifies another UE component, such as an application processor, so that appropriate action can be taken to mitigate operational and user experience issues caused by the radio link failure or impending failure.

[0049] In at least some embodiments, the CRM 312 further includes ARLC monitoring information 324 used by the ARLC monitoring module 322 to perform voice call ARLC monitoring operations. The ARLC monitoring information 324, in at least some embodiments, includes signal information 324-1, RLF information 324-2, PHY layer capability information 324-3, transmit power deficiency information 324-4, etc. The signal information 324-1, in at least some embodiments, includes information such as signal-related characteristics / parameters (e.g., RSRP, RSRQ, CINR, SINR, etc.), signal strength measurements, signal strength thresholds, etc. In at least some embodiments, the RLF information 324-2 information includes information such as out-of-sync indications (e.g., N310 indications), timer (e.g., T310 timer) information, synchronization indications (e.g., N311 indications), RLD indications, radio resource control (RRC) connection re-establishment indications, RLC retransmission indications, etc. The PHY layer capability information 324-3, in at least some embodiments, includes information such as uplink capability information and downlink capability information. Downlink PHY layer capability information includes, for example, downlink bandwidth requirements, current throughput at the RLC layer for dedicated voice radio bearers, PHY capability degrade indications, RLD indications, etc. Uplink PHY layer capability information includes, for example, RLCPDUs on dedicated bearers for ongoing voice traffic, currently achieved uplink PHY layer capabilities, PHY capability degrade indications, RLD indications, etc. The transmit power deficiency information 324-4, in at least some embodiments, includes information such as the number of instances where the transmit power deficiency is greater than the deficiency margin, the ratio of high deficiency instances, the ratio threshold, the throughput of voice packets in PLCPDUs, the throughput of generated voice traffic, and RLD indications.

[0050] FIG. 4 illustrates an exemplary system-on-chip (SoC) 400 that, in at least some embodiments, implements various aspects of the ARLC monitoring techniques described herein. The SoC 400 may include additional functionality and interfaces that are omitted from FIG. 4 for clarity. In at least some embodiments, the SoC 400 is embodied as or within any type of UE device 102 or another device / system for implementing ARLC monitoring for active voice calls. While described with reference to chip-based packaging, the components illustrated in FIG. 4 may be embodied as other system or component configurations, such as, but not limited to, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), an application specific standard product (ASSP), a digital signal processor (DSP), a complex programmable logic device (CPLD), a system-in-package (SiP), a package-on-package (PoP), a processing and communications chipset, a communications coprocessor, a sensor coprocessor, etc.

[0051] 4, the SoC 400 includes a communications transceiver 402 and a wireless modem 404 that enable wired or wireless communication of data 406 (e.g., received data, data being received, data scheduled for broadcast, packetized data, etc.). In at least some embodiments, the wireless modem 404 is a multi-mode multi-band modem or baseband processor that can be configured to communicate according to various communications protocols, according to different frequency bands, or combinations thereof. Additionally, in at least some embodiments, the wireless modem 404 includes a transceiver interface (not shown) for communicating coded or modulated signals with the transceiver circuitry.

[0052] In at least some embodiments, data 406 or other system content includes configuration settings for SoC 400 or various components, media content stored by the system, and / or information related to system users. Media content stored on SoC 400 includes any type of audio, video, and / or image data. SoC 400 also includes one or more data inputs 408 through which any type of data, media content, and / or input can be received, such as user input, user-selectable input (explicit or implicit), or other types of audio, video, and / or image data received from content or data sources. Alternatively, or additionally, data inputs 408 include various data interfaces, which can be implemented as any one or more of serial and / or parallel interfaces, wireless interfaces, network interfaces, or any other type of communication interface that enables communication with other devices or systems.

[0053] SoC 400 includes one or more processor cores 410 that process various computer-executable instructions to control the operation of SoC 400 and enable the voice call ARLC monitoring techniques. Alternatively, or additionally, SoC 400 is implemented in any one or combination of hardware, firmware, or fixed logic circuitry implemented in association with processing and control circuitry 412. While not shown, SoC 400 includes one or more buses, interconnects, crossbars, or fabrics that couple the various components within SoC 400.

[0054] The SoC 400 also includes memory 414 (e.g., a computer-readable medium), such as one or more memory circuits that enable persistent and / or non-transitory data storage and thus do not involve transient signals or carrier waves. Examples of memory 414 include RAM, SRAM, DRAM, NV-RAM, ROM, EPROM, or flash memory. The memory 414 provides data storage for system data 406, firmware 416, applications 418, and any other type of information and / or data related to operational aspects of the SoC 400. For example, the firmware 416, in at least some embodiments, is maintained as processor-executable instructions of an operating system (e.g., a real-time OS) in the memory 414 and executes on one or more processor cores 410.

[0055] Applications 418, in at least some embodiments, include any type of control application, software application, signal processing and control module, code specific to a particular system, abstraction module, gesture module, etc. In at least some embodiments, memory 414 also stores one or more of system components, utilities, or information for implementing aspects of the voice call ARLC monitoring techniques described herein, such as signal information 324-1, RLF information 324-2, PHY layer capability information 324-3, transmit power deficiency information 324-4, etc.

[0056] In at least some embodiments, SoC 400 includes an ARLC monitoring module 322. ARLC monitoring module 322, in at least some embodiments, is implemented in whole or in part through hardware or firmware, or at least in part within memory 414. In at least some embodiments, SoC 400 also includes additional processors or coprocessors that enable other functions, such as a graphics processor 420, an audio processor 422, and an image sensor processor 424. Graphics processor 420, in at least some embodiments, renders graphical content associated with the user interface, operating system, or applications of SoC 400. In some cases, audio processor 422 encodes or decodes audio data and signals, such as audio signals and information related to voice calls or encoded audio data for playback. Image sensor processor 424, in at least some embodiments, is coupled to an image sensor and provides image data processing, video capture, and other visual media conditioning and processing functions.

[0057] In at least some embodiments, SoC 400 also includes a security processor 426 that supports various security, encryption, and cryptographic operations, such as providing secure communication protocols and encrypted data storage. While not shown, security processor 426, in at least some embodiments, includes one or more crypto engines, crypto libraries, hash modules, or random number generators to support encryption and cryptographic processing of information or communications of SoC 400. Alternatively, or additionally, SoC 400 includes a position and location engine 428 and a sensor interface 430. Generally, position and location engine 428 provides positioning or location data by processing signals from a global navigation satellite system (GNSS) and / or other motion or inertial sensor data (e.g., dead reckoning). Sensor interface 430 enables SoC 400 to receive data from various sensors, such as capacitance sensors and motion sensors.

[0058] 5 illustrates an example configuration of a wireless communications processor (CP) 500 that, in at least some embodiments, implements various aspects of the ARLC monitoring techniques described herein. The SoC 400 may include additional functionality and interfaces that are omitted from FIG. 5 for clarity. Although generally referred to as a communications processor, the communications processor 500, in at least some embodiments, is implemented as a modem baseband processor, a software defined radio module, a configurable modem (e.g., a multi-mode, multi-band modem), a wireless data interface, or a wireless modem, such as the RF transceiver 306 of the UE device 102 or the wireless modem 404 of the SoC 400. In at least some embodiments, the communications processor 500 is implemented in a device or system, such as the UE device 102, to support wireless network data access, messaging, or database services, as well as various voice-based communications (e.g., voice calls).

[0059] In this example, communications processor 500 includes at least one processor core 502 and memory 504. Processor core 502, in at least some embodiments, is configured as any suitable type of processor core, microcontroller, digital signal processor core, etc. Memory 504 is implemented as hardware-based memory that enables persistent storage and eliminates propagating signals. In at least some embodiments, memory 504 includes any suitable type of memory device or circuitry, such as RAM, DRAM, SRAM, non-volatile memory, flash memory, etc. Generally, the memory stores data 506, firmware 508, and other applications for communications processor 500. Processor core 502, in at least some embodiments, executes processor-executable instructions in firmware 508 or applications to implement functions of communications processor 500, such as signal processing and data encoding operations. Memory 504, in at least some embodiments, also stores one or more system components, utilities, or information for implementing aspects of the voice call ARLC monitoring techniques described herein. For example, the memory 504 includes signal information 324-1, RLF information 324-2, PHY layer capability information 324-3, and transmission power deficiency information 324-4.

[0060] In at least some embodiments, the communications processor 500 includes an ARLC monitoring module 322. The ARLC monitoring module 322, in at least some embodiments, is implemented in whole or in part through hardware or firmware, or at least in part within the memory 504. The communications processor 500, in at least some embodiments, also includes electronic circuitry 510 for managing or coordinating the operation of various components, and a voice codec 512 for processing voice signals and data. In at least some embodiments, the electronic circuitry 510 includes hardware, fixed logic circuits, or physical interconnections (e.g., traces or connectors) implemented in association with the processing and control circuitry and various components of the communications processor 500. In at least some embodiments, the voice codec 512 includes a combination of logic, circuitry, or firmware (e.g., algorithms) for supporting the encoding and / or decoding of voice information and voice signals, such as analog signals and digital data, associated with the voice or audio functions of the communications processor 500.

[0061] The system interface 514 of the communications processor 500 enables communication with a host system or application processor. For example, the communications processor 500 provides or exposes data access functionality to the system or application processor via the system interface 514. In this example, the communications processor 500 also includes a transceiver circuit interface 516 and an RF circuit interface 518 through which the communications processor 500 manages or controls the respective functions of the transceiver circuitry or RF front end to implement various communications protocols and technologies. In various aspects, the communications processor 500 includes digital signal processing or signal processing blocks for encoding and modulating data for transmission or for demodulating and decoding received data.

[0062] In at least some embodiments, communications processor 500 includes an encoder 520, a modulator 522, and a digital-to-analog converter 524 (D / A converter 524) for encoding, modulating, and converting data to be transmitted to transceiver circuit interface 516. Communications processor 500 also includes an analog-to-digital converter 526 (A / D converter 526), ​​a demodulator 528, and a decoder 530 for converting, demodulating, and decoding data received from transceiver circuit interface 516. In at least some embodiments, these signal processing blocks and components are implemented as respective transmit and receive chains of communications processor 500 that are configurable for different radio access technologies or frequency bands.

[0063] Figure 6 shows a functional block diagram of a communications processor 602 that implements the ARLC monitoring module 322. In at least some embodiments, the communications processor 602 of Figure 6 is embodied as the communications processor 500 described above with respect to Figure 5. In the example shown in Figure 6, the communications processor 602 is communicatively coupled to one or more other components 604 of the UE device 102, such as an application processor. In at least some embodiments, the communications processor 602 is coupled to the UE component 604 via one or more interfaces 606, such as one or more messaging channels, to send information to and receive information from the UE component 604.

[0064] In at least some embodiments, the communications processor 602 implements a network protocol stack 608 (communications stack 608) through which the UE device 102 communicates with entities of the mobile cellular network 100. For example, the UE device 102 utilizes the communications stack 608 to communicate with entities such as a cell or core network of the mobile cellular network 100. Although not shown, the communications stack 608 includes a user plane and a control plane, each comprised of one or more of layers 610 (shown as layers 610-1 through 610-4). The upper layers of the user plane and control plane share a common lower layer within the communications stack 608. It should be understood that the terms “upper layer” and “lower layer” are interrelated, and each layer within the communications stack 608 is a lower layer (“lower layer”) from the “upper layer” within the communications stack 608. The UE device 102 implements each layer within the communications processor 602 as an entity for communicating with other devices using the respective protocol defined for that layer. For example, the UE device 102 uses an RRC entity to communicate with a peer RRC entity in the base station 104 using an appropriate RRC protocol or RRC connection.

[0065] The shared lower layers include a physical (PHY) layer 610-1 and one or more layers denoted as a data path layer 610-2. Examples of the shared lower layer, the data path layer 610-2, include a media access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer. Generally, the PHY layer 610-1 provides hardware specifications for devices communicating with each other, and the MAC layer specifies how data is transferred between devices. The RLC layer, for example, provides data transfer services to upper layers in the communications stack 608. For example, the RLC layer transfers protocol data units (PDUs) for the upper layers, performs error correction, etc. The PDCP layer provides data transfer services, for example, for user plane data and control plane data.

[0066] Above the PDCP layer, the communications stack 608 is divided into a user plane and a control plane. Layers in the user plane include, for example, an Internet Protocol (IP) layer, a transport layer (not shown), and an application layer (not shown). In at least some embodiments, the user plane also includes a Service Data Adaptation Protocol (SDAP) layer for implementing and managing quality of service (QoS) flows in 5G NR networks. Generally, the IP layer (shown in FIG. 6 as one of the data path layers 610-2) specifies how data from the application layer is forwarded to a destination node. The transport layer uses Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) for data forwarding by the application layer and verifies whether data packets intended for forwarding to the destination node have arrived at the destination node. In at least some embodiments, the user plane also includes a data service layer (not shown) that provides data transport services for forwarding application data, such as IP packets containing web browsing content, video content, image content, audio content, social media content, etc.

[0067] The control plane of the communications stack 608 includes an RRC layer 610-3 and one or more upper layers 610-4, such as an application layer / controller and a non-access layer (NAS) layer. The RRC layer performs radio connection and radio bearer establishment and release, system information broadcast, or power control. The NAS layer supports mobility management and packet data bearer context between the UE device 102 and entities or functions within the core network 112. In the example of FIG. 6, one or more of the upper layers 610-4 receive call-related information / requests 612 from the UE component 604 via the AP interface 606. For example, the UE component 604 provides a call request to the upper layers 610-4 along with associated call state information, such as network coverage information (e.g., LTE, 5G, etc.), IP Multimedia Subsystem (IMS) registration status, etc. In some examples, the UE component 604 provides voice data 614 to one or more upper layers 610-4 via the AP interface 606. In embodiments in which the UE device 102 implements the communications processor 602, each layer of the communications stack 608, both the user plane and the control plane, interacts with a corresponding peer layer or entity within the cell, a core network entity or function, and / or a remote service to support user applications and control the operation of the UE device 102 within the RAN 110.

[0068] In at least some embodiments, the communications processor 602 includes an ARLC monitoring module 322. As described above, the ARLC monitoring module 322 implements the ARLC detection mechanism 130 for detecting adverse radio link conditions and radio link failures in real time or near real time. The ARLC monitoring module 322, in at least some embodiments, integrates with the communications stack 608 to access various stack information / parameters 616 (shown as 616-1 through 616-4) from one or more layers 610 of the communications stack 608. For example, the ARLC monitoring module 322 accesses PHY layer information 616-1, such as signal information (e.g., signal strength quality), decoding information, transmit power information, radio link failure information, etc. In another example, the ARLC monitoring module 322 accesses data path layer information 616-2, such as data flow / loss information (e.g., data loss due to decoding errors, signal failures, etc.), Real-Time Transport Protocol (RTP) information, RTP Control Protocol (RTCP) information, etc. In yet another example, the ARLC monitoring module 322 accesses RRC layer information 616-3 such as network restriction information (e.g., periods when service to a group of devices is blocked or unavailable), handover information, connection setup / release information, etc. In a further example, the ARLC monitoring module 322 accesses higher layer information 616-4 such as setup status information (e.g., dial, ring, pick up / connect, etc.), registration status information (e.g., device service is limited), and congestion information.

[0069] In at least some embodiments, the ARLC monitoring module 322 is also coupled to the voice processing module 618 of the communications processor 602 to access voice gap information 620. Voice gaps typically occur during handover procedures when the UE device 102 disconnects from one cell and connects to another. The ARLC monitoring module 322 interacts with the voice processing module 618 to determine when voice gaps occur, their duration, etc. As described in more detail below, the ARLC monitoring module 322 monitors and processes the stack information 616, the voice gap information 620, or a combination thereof to detect or predict adverse radio link conditions that are likely to cause or potentially will cause RLD (e.g., radio link failure for a voice call or degraded voice conditions, etc.). The ARLC monitoring module 322 generates an output 622 (RLD indication 622) based on processing the stack information 616, the voice gap information 620, or a combination thereof. In at least some embodiments, the output 622 of the ARLC monitoring module 322 is a connection status indicator for an active voice call that indicates when a radio link failure has occurred or is likely to occur, the possible causes of the radio link failure or potential failure, etc. In at least some embodiments, the output 622 also indicates the possible causes of a degradation in voice quality that has occurred or is potentially occurring during an active voice call. In at least some embodiments, the output 622 indicates the cause of the RLD using a mechanism such as a flag, a bit, a bit mask, an array, etc. The ARLC monitoring module 322, in at least some embodiments, transmits the output 622 to the UE component 604 via the AP interface 606. In at least some embodiments, the UE component 604 utilizes the output 622 received from the ARLC monitoring module 322 to perform one or more actions, such as switching the active call to another mode (e.g., VoWiFi) to preserve the call, notifying the user that the call may be dropped or that the quality of the call may be degraded, notifying the user of the reason the call is being dropped, etc.

[0070] 7 and 8 together illustrate, in flowchart form, an example method 700 of the communications processor 500 (or another component) of the UE device 102 for performing a first mode of ARLC monitoring based on low signal strength. In this example method 700, the ARLC monitoring module 322 monitors signal strength updates performed by the UE device 102 to detect occurrences of low signal strength. If low signal strength is detected a threshold number of times, the ARLC monitoring module 322 notifies another component of the UE device 102, such as the UE component 604, of the RLD condition and a possible cause of the RLD condition, such as a drop in signal strength.

[0071] 7, block 702, the ARLC monitoring module 322 detects an active voice call 701 on the UE device 102. For example, a user of the UE device 102 makes an outgoing voice call or receives an incoming voice call using one or more applications executing on the UE device 102. In at least some embodiments, the ARLC monitoring module 322 determines that the voice call 701 has been initiated based on monitoring the communication stack 608. The ARLC monitoring module 322 initially sets a low signal indication 703 to FALSE (or equivalent) in response to the initiation of the voice call at block 704. In at least some embodiments, the low signal indication 703 is a flag, bit, bit mask, array, or other mechanism implemented by the ARLC monitoring module 322 to track when low signal strength is detected for the current voice call 701.

[0072] The ARLC monitoring module 322 monitors one or more layers 610 of the communication stack 608 during the active voice call 701. At least one parameter related to maintaining the active voice call may be monitored across the one or more layers 610. The ARLC monitoring module 322 determines in block 706 that the UE device 102 has performed a signal strength update 705. For example, the ARLC monitoring module 322 monitors the communication stack 608 for information or a message indicating that the signal strength update 705 has been performed. In another example, one or more components of the UE device 102 notify the ARLC monitoring module 322 that the signal strength update 705 has been performed. In at least some embodiments, the UE device 102 performs the signal strength update 705 by calculating the signal strength of one or more signals of the serving cell and / or target cell in response to one or more triggering events. For example, the UE device 102 typically measures signal strength for handover events when the UE device 102 is in a connected mode (e.g., when a voice call is active). In another example, the UE device 102 measures signal strength periodically or in response to other triggering events. The UE device 102 determines the signal strength metric based on a specific RRC message received from the base station 104.

[0073] In at least some embodiments, one or more components of the UE device 102, such as the communications processor 500, determine the signal strength of a cell based on signal (strength)-related characteristics 707. In the case of an LTE-based signal, the UE device 102 determines signal-related characteristics related to a cell-specific reference signal (CRS). In the case of a 5GNR-based signal, the UE device 102 determines signal-related characteristics related to a synchronization signal (SS) and channel state information (CSI) instead of a CRS. Examples of signal-related characteristics 707 include measurements such as RSRP, RSRQ, and CINR / SINR. The RSRP measurement is defined as the average power (in watts) of resource elements (REs) carrying a cell-specific reference signal (RS) within a considered bandwidth. In other words, the RSRP measurement is a power measurement of a signal subcarrier. The RSRQ measurement is defined as the ratio of the reference signal power to the total and indicates the quality of the received signal. The CINR / SINR measurement is defined as the signal strength of a specific signal of interest divided by the sum of the signal strength of co-channel interfering signals and thermal noise generated by the receiver electronics. In at least some embodiments, the ARLC monitoring module 322 obtains at least one of the signal-related characteristics 707 from one or more layers 610 of the communications stack 608, a component of the UE device 102, a memory / storage device (e.g., CRM 312) of the UE device 102, etc. In one example, the ARLC monitoring module 322 receives the signal-related characteristics 707 as part of PHY layer information 616-1 and stores this information 616-1 as signal information 324-1.

[0074] Upon determining that a signal strength update 705 has occurred, the ARLC monitoring module 322 compares one or more signal-related characteristics 707 with corresponding low signal thresholds 709. However, in at least some embodiments, the ARLC monitoring module 322 first determines, at block 708, whether transmission time interval (TTI) bundling is enabled, e.g., based on information obtained from the PHY layer 610-1. Typically, TTI bundling is enabled to optimize uplink coverage at the cell edge for services such as Voice over LTE (VoLTE). When TTI bundling is enabled, the UE device 102 transmits the same packet for a predetermined number of consecutive TTIs to increase radio link robustness. If TTI bundling is enabled, the ARLC monitoring module 322 selects, at block 710, a first set 709-1 of low signal thresholds for the signal-related characteristics 707. If TTI bundling is disabled, the ARLC monitoring module 322 selects a second set of low signal thresholds 709-2 for the signal-related characteristics 707 at block 712. In at least some embodiments, the low signal thresholds 709 are values ​​or ranges of values ​​that are compared with corresponding signal-related characteristics to determine whether an instance of low signal strength has occurred. In at least some embodiments, the second set of low signal thresholds 709-2 are set lower than the first set of low signal thresholds 709-1 because this increases the robustness of the radio link when the UE device 102 is at the cell edge and TTI is enabled. In at least some embodiments, the first set of low signal thresholds 709-1 and the second set of low signal thresholds 709-2 each include an RSRP threshold, an RSRQ threshold, and a CINR / SINR threshold. In at least some embodiments, TTI bundling is not considered, and the method flows directly from block 706 to block 710.

[0075] The ARLC monitoring module 322 compares one or more signal-related characteristics 707 to corresponding low-signal thresholds, either a first set of low-signal thresholds 709-1 or a second set of low-signal thresholds 709-2, depending on whether TTI bundling is enabled and considered, at block 714. For example, the ARLC monitoring module 322 compares the RSRP measurement to an RSRQ threshold, the RSRQ measurement to an RSRQ threshold, the CINR / SINR measurement to a CINR / SINR threshold, or a combination thereof. In one example, when TTI is not enabled, the ARLC monitoring module 322 determines whether one or more RSRP measurements are less than −125 decibel milliwatts (dBm), the RSRQ measurement is less than −20 decibels (dB), or the CINR / SINR measurements are less than −3 dB, or a combination thereof. In an example where TTI is enabled, the ARLC monitoring module 322 determines whether one or more RSRP measurements are less than −120 dBm, RSRQ measurements are less than −15 dB, or CINR / SINR measurements are less than 0 dB, or a combination thereof. It should be understood that these thresholds are for illustrative purposes only, and other thresholds (or ranges of values) are also applicable.

[0076] The ARLC monitoring module 322 determines, at block 716, whether each of the one or more signal-related characteristics 707 meets or does not meet a corresponding low-signal threshold 709. It should be understood that throughout this description, meeting or not meeting a threshold refers to a corresponding value that is either less than, greater than, or equal to the threshold, depending on how the threshold and comparison process are configured. In one example, not meeting the low-signal threshold 709 indicates that the signal-related characteristic 707 has a value that is equal to or greater than the low-signal threshold 709. However, the low-signal threshold 709 can be configured such that, in other examples, meeting the low-signal threshold 709 indicates that an instance of a low signal has not occurred.

[0077] In the current example, if each of the one or more signal-related characteristics 707 does not meet the corresponding low signal threshold 709, then in block 718 the ARLC monitoring module 322 determines that no low signal instances have occurred and sets the low signal count 711 to 0. The ARLC monitoring module 322 determines whether the low signal indication 703 is set to FALSE (or equivalent) in block 720. If the low signal indication 703 is not set to FALSE, then flow returns to block 704, where the ARLC monitoring module 322 sets the low signal indication 703 to FALSE. However, if the ARLC monitoring module 322 determines that the low signal indication 703 is set to FALSE, then flow returns to block 706, where the ARLC monitoring module 322 monitors signal strength updates 705.

[0078] If any of the one or more signal-related characteristics 707 meets the corresponding low signal threshold 709, the ARLC monitoring module 322 increments the low signal count 711, at block 722. The ARLC monitoring module 322 compares the low signal count 711 to the low signal count threshold 713, at block 724 (FIG. 8). The ARLC monitoring module 322 determines whether the low signal count 711 meets the low signal count threshold 713, at block 726. If the low signal count 711 does not meet the low signal count threshold 713, flow returns to block 706, where the ARLC monitoring module 322 monitors for signal strength updates 705. However, if the low signal count 711 meets the low signal count threshold 713, then the ARLC monitoring module 322 determines whether the low signal indication 703 is currently set to FALSE, at block 728. If the signal indication 703 is currently set to FALSE, the ARLC monitoring module 322 sets the low signal indication 703 to TRUE (or equivalent) at block 730. Otherwise, flow returns to block 706, where the ARLC monitoring module 322 monitors signal strength updates 705. If the low signal indication 703 is set to TRUE, the ARLC monitoring module 322 has detected a low signal condition 715 (or a potential low signal condition) for a radio link associated with an active voice call. For example, in response to monitoring one or more of layers 610, at least one adverse radio link condition associated with an active voice call is detected. In at least some embodiments, the detection is based on a monitored parameter that can meet a low signal condition or criteria.

[0079] Upon setting the low signal indication 703 to FALSE, the ARLC monitoring module 322 generates an RLD indication 622 at block 732 and transmits the RLD indication 622 to one or more UE components 604, such as an application processor. For example, the radio link degradation (RLD) indication 622 is provided to a component 604 of the UE device 102 in response to detecting at least one adverse radio link condition. In at least some embodiments, the RLD indication 622 includes information indicating that a radio link degradation has occurred or is likely to occur to an active voice call, and also includes a possible cause of the RLD, such as the detected low signal condition 715. In at least some embodiments, the RLD indication 622 also includes one or more of the RSRP, RSRQ, and CINR / SINR measurements used to determine that the low signal condition 715 has occurred. In at least some embodiments, the UE component 604 utilizes the RLD indication 622 to perform one or more actions, such as switching the active call to another mode (e.g., VoWiFi) to preserve the call, notifying the user that the call may be dropped or that the call quality may be degraded, notifying the user of the reason the call is being dropped, etc. Flow returns to block 706, where the ARLC monitoring module 322 monitors for signal strength updates 705. The above process repeats until the voice call 701 is ended or dropped.

[0080] 9 illustrates, in flowchart form, an example method 900 of the communications processor 500 (or another component) of the UE device 102 for performing a second mode of ARLC monitoring based on RLF. In this example method 900, the ARLC monitoring module 322 monitors for RLF due to an out-of-sync condition. Referring to block 902 of FIG. 9 , the ARLC monitoring module 322 detects an active voice call 901 on the UE device 102. For example, a user of the UE device 102 places an outgoing voice call or receives an incoming voice call using one or more applications executing on the UE device 102. In at least some embodiments, the ARLC monitoring module 322 determines that the voice call 901 has been initiated based on monitoring the communications stack 608.

[0081] The ARLC monitoring module 322 monitors one or more layers 610 of the communications stack 608 during the active voice call 701. At least one parameter related to maintaining the active voice call may be monitored across the one or more layers 610. The ARLC monitoring module 322 monitors an out-of-sync indication 903 (e.g., an N310 indication) related to the active voice call at block 904. In one example, an out-of-sync condition occurs when the UE device 102 is unable to successfully decode a PDCCH. In at least some embodiments, the UE device 102 monitors one or more layers 610 of the communications stack 608 to detect when an out-of-sync indication 903 is generated. The ARLC monitoring module 322 determines whether an out-of-sync indication 903 is detected at block 906. If an out-of-sync indication 903 is not detected, the ARLC monitoring module 322 continues to monitor for an out-of-sync indication 903 at block 904. However, if an out-of-sync indication 903 is detected, the ARLC monitoring module 322 determines, in block 908, whether to start an RLF timer 905 (e.g., a T310 timer). In at least some embodiments, the RLF timer 905 is started by one or more network protocol stack layers 610 after a threshold number of consecutive out-of-sync indications 903 are received / detected. The ARLC monitoring module 322, in at least some embodiments, monitors the network protocol stack layers 610 to detect when the RLF timer 905 is started. If the RLF timer 905 is not started, flow returns to block 904, where the ARLC monitoring module 322 continues to monitor the out-of-sync condition. However, if the RLF timer 905 is started, the ARLC monitoring module 322 performs one of several options.

[0082] In a first option, the ARLC monitoring module 322 determines whether the RLF timer 905 has expired in block 910. If the RLF timer 905 has not expired, the ARLC monitoring module 322 continues to monitor the expiration of the RLF timer 905. If the RLF timer 905 has expired, the ARLC monitoring module 322 determines that an RLF 907 has occurred in block 912. For example, in response to monitoring one or more of the layers 610, at least one adverse radio link condition associated with an active voice call is detected. In one example, the detection is based on monitored parameters that can satisfy an RLF condition or criterion.

[0083] The ARLC monitoring module 322, at block 914, sets an internal RLD indication 622 and transmits the RLD indication 622 to one or more components 604 of the UE device 102, such as an application processor. For example, the radio link degradation (RLD) indication 622 is provided to the component 604 of the UE device 102 in response to detecting at least one adverse radio link condition. In at least some embodiments, the RLD indication 622 includes information indicating that a radio link failure has occurred or is likely to occur for an active voice call, and also includes a possible cause of the RLD, such as an out-of-sync condition. In at least some embodiments, the UE component 604 utilizes the RLD indication 622 to perform one or more actions, such as switching the active call to another mode (e.g., VoWiFi) to preserve the call, notifying the user that the call may be dropped or that the call quality may be degraded, notifying the user of the reason the call is being dropped, etc. The ARLC monitoring module 322 monitors one or more network protocol stack layers 610 in block 916 and resets the internal RLD indication 622 upon detecting one or more events, such as a synchronization state / indication 909, a successful RRC re-establishment 911, or a call disconnection 913. An example of a synchronization indication is defined in the 3GPP standards for 4G LTE and 5G NR. The N311 indication identifies the number of intervals during which the UE device 102 was able to successfully decode the PDCCH while the RLF timer 905 was running. The UE device 102, in at least some embodiments, performs an RRC re-establishment procedure upon expiration of the RLF timer 905. If the RRC re-establishment process fails, the call is disconnected. In at least some embodiments, if the UE component 604 processes an RLD indication on a per-call basis, the UE component 604 clears the RLD indication 907 received from the ARLC monitoring module 322.

[0084] In a second option, the ARLC monitoring module 322 sets an internal RLD indication 907 and sends the RLD indication 907 to the UE component 604 at block 918 when the RLF timer 905 starts. For example, a radio link degradation (RLD) indication 622 is provided to the component 604 of the UE device 102 in response to detecting at least one adverse radio link condition. The ARLC monitoring module 322 monitors one or more network protocol stack layers 610 at block 920 and resets the internal RLD indication 622 upon detecting one or more events, such as a synchronization indication 909, a successful RRC re-establishment 911, a call disconnection 913, etc. In at least some embodiments, if the UE component 604 processes the RLD indication on a per-call basis, the UE component 604 clears the RLD indication 907 received from the ARLC monitoring module 322.

[0085] FIG. 10 illustrates, in flowchart form, another exemplary method 1000 of the communications processor 500 (or another component) of the UE device 102 for performing a second mode of ARLC monitoring based on radio link failure (RLF). In the exemplary method 1000, the ARLC monitoring module 322 monitors for RLF due to an RLC maximum retransmission condition that occurs during data traffic transmission when the UE device 102 is in RLC acknowledged mode (AM). For example, voice traffic is typically transmitted using RLC unacknowledged (UM) mode and is not retransmitted. However, data traffic is typically transmitted using RLC ACK mode. In ACK mode, RLF is triggered when the maximum retransmission threshold is reached. An RLF for data traffic indicates that there are problems with the radio conditions for both data and voice traffic, and that its data radio bearers (DRBs) should also be similarly affected. Furthermore, if re-establishment of the RRC connection for data traffic is not successful, the DRBs for both voice and data traffic are disconnected, resulting in a disconnection of the voice call. Thus, in the example method 1000 shown in FIG. 10, the ARLC monitoring module 322 monitors RLC retransmissions even if the retransmissions are not for voice traffic.

[0086] 10 , block 1002, the ARLC monitoring module 322 detects an active voice call 1001 on the UE device 102. For example, a user of the UE device 102 makes an outgoing voice call or receives an incoming voice call using one or more applications executing on the UE device 102. In at least some embodiments, the ARLC monitoring module 322 determines that the voice call 1001 has been initiated based on monitoring the communication stack 608. The ARLC monitoring module 322 monitors one or more network protocol stack layers 610 (e.g., the RLC layer 1003) and determines that an RLC maximum retransmission condition 1005 has occurred in block 1004. For example, the ARLC monitoring module 322 monitors one or more layers 610 of the communication stack 608 during the active voice call 701. At least one parameter associated with maintaining the active voice call may be monitored across the one or more layers 610. The RLC max retransmission state 1005 occurs, for example, when the UE device 102 receives a STATUS PDU containing negative acknowledgement (NACK) information indicating that some PDUs were not received in a previous transmission. In response, the UE device 102 attempts to retransmit the lost PDUs. Retransmissions occur until all PDUs are received by the receiving entity or a maximum retransmission threshold for the PDU associated with the NACK is reached. If the maximum retransmission threshold is reached, the RLC max retransmission state 1005 occurs and is detected by one or more network protocol stack layers 610. For example, in response to monitoring of the multiple layers 610, at least one adverse radio link condition associated with an active voice call is detected. In at least some embodiments, the detection is based on monitored parameters that can satisfy an RLC max retransmission condition or criterion.

[0087] The ARLC monitoring module 322 configures an internal RLD indication 622 and transmits the RLD indication 622 to one or more UE components 604, such as an application processor, at block 1006. For example, the radio link degradation (RLD) indication 622 is provided to the component 604 of the UE device 102 in response to detecting at least one adverse radio link condition. In at least some embodiments, the RLD indication 622 includes information indicating that a radio link failure has occurred or is likely to occur for an active voice call, and also includes a possible cause of the RLD, such as RLC maximum retransmissions. In at least some embodiments, the UE component 604 utilizes the RLD indication 622 to perform one or more actions, such as switching the active call to another mode (e.g., VoWiFi) to preserve the call, notifying the user that the call may be dropped or that the call quality may be degraded, notifying the user of the reason the call is being dropped, etc.

[0088] The ARLC monitoring module 322 monitors one or more of the network protocol stack layers 610 and determines, in block 1008, that the UE device 102 is attempting an RRC re-establishment operation 1007. The ARLC monitoring module 322 determines, in block 1010, whether the RRC re-establishment operation 1007 was successful. If the RRC re-establishment operation 1007 failed, the ARLC monitoring module 322 clears / resets its RLD indication 622 (e.g., status=FALSE) in block 1012. The ARLC monitoring module 322 then monitors for new active voice calls in block 1022. If the RRC re-establishment operation 1007 was successful, the ARLC monitoring module 322 determines, in block 1014, whether other ARLC (RLD factors or parameters) 1009 are causing or potentially causing radio link degradation. Examples of these other monitored parameters or factors 1009 include a low signal condition, an out-of-sync condition, a PHY low functionality condition, and an insufficient Tx power condition, as described herein. If at least one factor 1009 is causing or potentially causing RLD, the ARLC monitoring module 322 sends an RLD indication update 1011 to the UE component 604 with an RLF triggering event bitmask 1013 cleared, in block 1016. In at least one embodiment, the RLF triggering event bitmask 1013 is a bitmask sent as part of the RLD indication 622 indicating that an RLF has occurred. The RLF triggering event bitmask 1013, in at least some embodiments, also identifies the cause of the RLF. If there are no factors 1009 causing RLD or no factors 1009 that could potentially cause RLD, the ARLC monitoring module 322 clears / resets its RLD indication 622 (e.g., status=FALSE), in block 1018. The ARLC monitoring module 322 determines whether the voice call 1001 is still active in block 1020. If so, flow returns to block 1004. If the voice call 901 is no longer active, the ARLC monitoring module 322 monitors for new active voice calls in block 1022.

[0089] FIG. 11 illustrates, in flowchart form, an example method 1100 of the communications processor 500 (or another component) of the UE device 102 performing a third mode of ARLC monitoring based on the capabilities of the PHY layer 610-1 on the downlink. Typically, voice traffic is prioritized over data traffic. However, if the overall PHY capability (throughput) is lower than the bandwidth required to transmit ongoing voice traffic, the voice call may be dropped. Examples of factors limiting PHY capability include high BLER, limited resource block (RB) allocation from the network, etc. Therefore, in the example method 1100 of FIG. 11, the ARLC monitoring module 322 monitors low PHY capability 1115 as a detrimental radio link condition.

[0090] 11 , block 1102, the ARLC monitoring module 322 detects an active voice call 1101 at the UE device 102. For example, a user of the UE device 102 makes an outgoing voice call or receives an incoming voice call using one or more applications executing on the UE device 102. In at least some embodiments, the ARLC monitoring module 322 determines that the voice call 1101 has been initiated based on monitoring the communication stack 608. The ARLC monitoring module 322, at block 1104, monitors one or more network protocol stack layers 610 (e.g., PHY layer 610-1) to calculate the downlink bandwidth (T_voice_dl) 1103 required for the current voice traffic based on, for example, call characteristics 1105, such as the type of codec used for the voice call 1101 and the voice pattern (e.g., active or silent). The ARLC monitoring module 322 also monitors one or more other network protocol stack layers 610 (e.g., the RLC layer 1107) in block 1106 to determine the current throughput of the dedicated voice radio bearer (T_rlc_dl) 1109, which is limited by the PHY capabilities at that network protocol stack layer 610. For example, the ARLC monitoring module 322 monitors one or more layers 610 of the communication stack 608 during the active voice call 701. At least one parameter related to maintaining the active voice call may be monitored across the one or more layers 610.

[0091] In block 1108, the ARLC monitoring module 322 compares the required downlink bandwidth (T_voice_dl) 1103 with the current throughput of the dedicated voice radio bearer (T_rlc_dl) 1109 multiplied by an adjustment factor (coef_dl) 1111, which is based on the ratio of the required voice bandwidth to the actual available bandwidth. In block 1110, the ARLC monitoring module 322 determines whether the required downlink bandwidth 1103 is greater than the adjusted current throughput of the dedicated voice radio bearer 1109 (i.e., T_voice_dl > (T_rlc_dl * coef_dl)). If the required downlink bandwidth 1103 is not greater than the adjusted current throughput of the dedicated voice radio bearer 1109, control flow returns to block 1104, and the actions of blocks 1104 through 1112 are repeated until the voice call 1101 is terminated or disconnected. If the required downlink bandwidth 1103 is greater than the adjusted current throughput 1109 of the dedicated voice radio bearer, the ARLC monitoring module 322 increments the low PHY capability count 1113 in block 1112 .

[0092] The ARLC monitoring module 322 determines whether the internal RLD indication 622 is set (e.g., status=TRUE) at block 1114. If the internal RLD indication 622 is not set, the ARLC monitoring module 322 determines whether the low PHY capability count 1113 is greater than (or equal to) the low PHY capability count threshold 1117 (N_th 1117) at block 1116. If so, the ARLC monitoring module 322 determines that a low PHY capability condition (1115) is detected and sets the internal RLD indication 622 (e.g., status=TRUE) at block 1118. For example, in response to monitoring the multiple layers 610, at least one adverse radio link condition associated with an active voice call is detected. In at least some embodiments, the detection is based on monitored parameters that can meet a low PHY capability condition or criterion.

[0093] The ARLC monitoring module 322 also transmits an RLD indication 622 to one or more UE components 604, such as an application processor. For example, the radio link degradation (RLD) indication 622 is provided to the component 604 of the UE device 102 in response to detecting at least one adverse radio link condition. In at least some embodiments, the RLD indication 622 includes information indicating that a radio link degradation has occurred or is likely to occur to an active voice call, and also includes a possible cause of the RLD, such as low PHY capabilities on the downlink. In at least some embodiments, the UE component 604 utilizes the RLD indication 622 to perform one or more actions, such as switching the active call to another mode (e.g., VoWiFi) to preserve the call, notifying the user that the call may be dropped or that the call quality may be degraded, notifying the user of the reason the call is being dropped, etc. Control flow returns to block 1104, and the operations of blocks 1104-1118 are repeated until the voice call 1101 is terminated or dropped. If the low PHY capability count 1113 does not meet (e.g., is less than) the low PHY capability count threshold 1117, the control flow returns to block 1104 and the actions of blocks 1104 through 1116 are repeated until the voice call 1101 is ended or disconnected.

[0094] Referring back to block 1114, if the internal RLD indication 622 is set, the ARLC monitoring module 322 determines, in block 1120, whether the low PHY capability count 1113 is less than the low PHY capability count threshold 1117. If the low PHY capability count 1113 is greater than or equal to the low PHY capability count threshold 1117, control flow returns to block 1104, and the operations of blocks 1104 through 1120 are repeated until the voice call 1101 is terminated or disconnected. If the low PHY capability count 1113 is less than the low PHY capability count threshold 1117, the ARLC monitoring module 322 clears / resets its internal RLD indication 1117 (e.g., status=FALSE) in block 1122. Control flow returns to block 1104, and the operations of blocks 1104 through 1122 are repeated until the voice call 1101 is terminated or disconnected. Additionally, if at any time the ARLC monitoring module 322 determines that the voice call has been dropped, the ARLC monitoring module 322 clears / resets its internal RLD indication 622 and monitors the active voice call.

[0095] 12 illustrates, in flowchart form, another exemplary method 1200 of the communications processor 500 (or another component) of the UE device 102 for performing a third mode of ARLC monitoring based on the capabilities of the PHY layer 610-1 on the uplink. Similar to the downlink example described above, voice traffic is prioritized over data traffic. However, if the PHY capabilities cannot support the voice traffic generated by the UE device 102, the voice call will likely be dropped, or at least the voice quality will be degraded. Unlike traffic on the downlink, the amount of desired uplink voice traffic is generated locally by the UE device 102 (RTP packets → RLCPDUs). Therefore, there is no need to estimate the voice traffic as was done in the downlink example.

[0096] Referring to block 1202 of FIG. 12 , the ARLC monitoring module 322 detects an active voice call 1201 on the UE device 102. For example, a user of the UE device 102 makes an outgoing voice call or receives an incoming voice call using one or more applications executing on the UE device 102. In at least some embodiments, the ARLC monitoring module 322 determines that the voice call 1201 has been initiated based on monitoring the communication stack 608. The ARLC monitoring module 322 monitors one or more of the network protocol stack layers 610 (e.g., the RLC layer 1203) in block 1204 to determine the bandwidth (T_voice_ul) 205 required for outgoing voice traffic on the dedicated bearer based on the RLCPDU. The ARLC monitoring module 322 monitors the PHY layer 610-1 in block 1206 to obtain the currently achieved uplink PHY capacity / throughput 1207 (T_phy_ul 1207). Various factors affect the uplink PHY capacity / throughput 1207. Examples of these factors include uplink allocation, Tx power, retransmissions due to NACK (BLER), etc. Thus, in at least some embodiments, the ARLC monitoring module 322 monitors one or more parameters related to maintaining an active voice call across at least one layer of the communications stack 608.

[0097] The ARLC monitoring module 322 compares the required bandwidth (T_voice_ul) with the uplink PHY capability 1207 (T_phy_ul) multiplied by the adjustment factor 1209 (coef_ul) in block 1208. The ARLC monitoring module 322 determines whether the required bandwidth 1205 is greater than the adjusted uplink PHY capability 1207 (i.e., whether T_voice_ul > (T_phy_ul * coef_ul)) in block 1210. If the required bandwidth 1205 is not greater than the adjusted uplink PHY capability 1207, control flow returns to block 1204, and the actions of blocks 1204 through 1210 are repeated until the voice call 1201 is ended or disconnected. However, if the required bandwidth 1205 is greater than the adjusted uplink PHY capability 1207, the ARLC monitoring module 322 determines, in block 1212, that a low PHY capability condition 1213 exists and increments the low PHY capability count (N_low_ul) 1211. For example, at least one adverse radio link condition associated with an active voice call is detected based on monitored parameters that can meet a low PHY capability condition or criterion.

[0098] The ARLC monitoring module 322 determines whether an internal RLD indication 622 is set (e.g., status=TRUE) at block 1214. If the internal RLD indication 622 is not set, the ARLC monitoring module 322 determines whether the low PHY capability count 1211 is greater than (or equal to) a low PHY capability count threshold 1215(N_th) 1215 at block 1216. If so, the ARLC monitoring module 322 sets the internal RLD indication 622 (e.g., status=TRUE) at block 1218 and transmits the RLD indication 622 to one or more UE components, such as an application processor. For example, a radio link degradation (RLD) indication 622 is provided to the component 604 of the UE device 102 in response to detecting at least one adverse radio link condition. In at least some embodiments, the RLD indication 622 includes information indicating that a radio link degradation has occurred or is likely to occur for an active voice call and includes a possible cause of the RLD, such as low PHY capability 1213 on the uplink. In at least some embodiments, the UE component 604 utilizes the RLD indication 622 to perform one or more actions, such as switching the active call to another mode (e.g., VoWiFi) to preserve the call, notifying the user that the call may be dropped or that the quality of the call may be degraded, notifying the user of the reason the call is being dropped, etc. Control flow returns to block 1204, and the operations of blocks 1204 through 1218 are repeated until the voice call 1201 is ended or disconnected. If the low PHY capability count 1211 does not meet (e.g., is less than) the low PHY capability count threshold 1215, control flow returns to block 1204, and the operations of blocks 1204 through 1218 are repeated until the voice call 1201 is ended or disconnected.

[0099] Referring back to block 1214, if the internal RLD indication 622 is set, the ARLC monitoring module 322 determines, in block 1220, whether the low PHY capability count 1211 is less than the low PHY capability count threshold 1215. If the low PHY capability count 1211 is greater than or equal to the low PHY capability count threshold 1215, control flow returns to block 1204, and the operations of blocks 1204 through 1220 are repeated until the voice call 1101 is ended or disconnected. If the low PHY capability count 1211 is less than the low PHY capability count threshold 1215, the ARLC monitoring module 322 clears / resets the internal RLD indication 622 (e.g., status=FALSE) in block 1222. Control flow returns to block 1204, and the operations of blocks 1204 through 1222 are repeated until the voice call 1201 is ended or disconnected. Additionally, if at any time the ARLC monitoring module 322 determines that the voice call has been dropped, the ARLC monitoring module 322 clears / resets its internal RLD indication 622 and monitors the active voice call.

[0100] FIG. 13 illustrates, in flowchart form, an example method 1300 of the communications processor 500 (or another component) of the UE device 102 for performing a fourth mode of ARLC monitoring based on a transmit power deficiency. In at least some embodiments, the Tx power deficiency is equal to the target Tx power minus the actual Tx power. The Tx power deficiency typically occurs due to an MTPL upper limit or an internal error. The Tx power deficiency typically causes the actual applied Tx power to be lower than the MTPL, which can result in active voice calls being dropped or voice quality degradation. Therefore, in the example method 1300 of FIG. 13, the ARLC monitoring module 322 monitors the Tx power deficiency. In at least some embodiments, the ARLC monitoring module 322 also monitors RLCPDU flows on dedicated voice radio bearers to more accurately estimate the impact of Tx power on voice traffic.

[0101] 13 , block 1302, the ARLC monitoring module 322 detects an active voice call 1301 at the UE device 102. For example, a user of the UE device 102 makes an outgoing voice call or receives an incoming voice call using one or more applications executing on the UE device 102. In at least some embodiments, the ARLC monitoring module 322 determines that the voice call 1301 has been initiated based on monitoring the communication stack 608. The ARLC monitoring module 322 monitors one or more of the network protocol stack layers 610 (e.g., PHY layer 610-1) at block 1304 and detects a Tx power deficiency (P_d) 1303 during the active voice call 1301. For example, the ARLC monitoring module 322 monitors one or more layers 610 of the multiple layers of the communication stack 608 during the active voice call 701. At least one parameter associated with maintaining the active voice call may be monitored across the one or more layers 610. In at least some embodiments, the ARLC monitoring module 322 determines that a Tx power deficit 1303 exists by obtaining target Tx power information 1305 and actual Tx power information 1307 from the PHY layer 610-1. If the actual Tx power is less than the target Tx power, a Tx power deficit exists. The ARLC monitoring module 322 compares the Tx power deficit 1303 to a Tx power deficit margin / threshold (Th) 1309 in block 1306. If the Tx power deficit 1303 does not meet (e.g., is less than) the Tx power deficit margin 1309, control flow returns to block 1304. However, if the Tx power deficit 1303 meets (e.g., is greater than) the Tx power deficit margin 1309, the ARLC monitoring module 322 considers this Tx power deficit instance to be a “high” Tx power deficit state 1311 in block 1308 and increments the high Tx power deficit count 1313.

[0102] The ARLC monitoring module 322 determines a high Tx power deficit count ratio 1315 for one or more monitoring windows of N Tx instances in block 1310. For example, if N=10 and the Tx power deficit count for these 10 Tx instances is 7, then the high Tx power deficit count ratio is calculated as 7 / 10=70%. The ARLC monitoring module 322 compares the ratio 1315 to a ratio threshold 1317 in block 1312. If the ratio 1315 does not meet (e.g., is less than) the ratio threshold 1317, then the ARLC monitoring module 322 determines that the UE device 102 is not in a power-limited state and clears / resets any RLD indications 622 in block 1314. Control proceeds to block 1304, where the actions of blocks 1304 through 1314 are repeated until the voice call 1301 is ended or disconnected. If the ratio 1315 meets (eg, is greater than) the ratio threshold 1317, the ARLC monitoring module 322 determines, in block 1316, that the UE device 102 is in a power-limited state.

[0103] The ARLC monitoring module 322 monitors one or more network protocol stack layers 610 to determine a throughput of voice packets (TPUT_v) 1319 from the RLC PDC, at block 1318. The ARLC monitoring module 322 also monitors one or more network protocol stack layers 610 to determine a codec-dependent throughput of generated voice packets (TPUT_gen) 1321, at block 1320. The ARLC monitoring module 322 determines whether TPUT_v 1319 is less than TPUT_gen 1321 multiplied by a coefficient (coef) 1323, at block 1322. For example, in response to monitoring the multiple layers 610, at least one adverse radio link condition associated with an active voice call is detected. In at least some embodiments, the detection is based on the monitored parameters being able to meet a condition or criterion of TPUT_v 1319 being less than TPUT_gen 1321 multiplied by the coefficient (coef) 1323.

[0104] If TPUT_v 1319 is less than TPUT_gen 1321 multiplied by a coefficient (coef) 1323, the ARLC monitoring module 322 sets an internal RLD indication 622 (e.g., status=TRUE) and transmits the RLD indication 622 to one or more UE components, such as an application processor, at block 1324. For example, the radio link degradation (RLD) indication 622 is provided to the component 604 of the UE device 102 in response to detecting at least one adverse radio link condition. In at least some embodiments, the RLD indication 622 includes information indicating that a radio link degradation has occurred or is likely to occur for an active voice call, and also includes a possible cause of the RLD, such as a high Tx power deficiency. In at least some embodiments, the UE component 604 utilizes the RLD indication 622 to perform one or more actions, such as switching the active call to another mode (e.g., VoWiFi) to preserve the call, notifying the user that the call may be dropped or that the call quality may be degraded, notifying the user of the reason the call is being dropped, etc. If TPUT_v 1319 is greater than (or equal to) TPUT_gen 1321 multiplied by a coefficient 1323, the ARLC monitoring module 322 clears / resets any RLD indications 622 in block 1326. If the voice call 1301 is still active, control proceeds to block 1304, where the actions of blocks 1304 through 1326 are repeated until the voice call 1301 is ended or dropped. Also, if at any time the ARLC monitoring module 322 determines that the voice call has been dropped, the ARLC monitoring module 322 clears / resets its internal RLD indication 622 and monitors the active voice call.

[0105] In some embodiments, certain aspects of the above-described techniques may be implemented by one or more processors of a processing system executing software. The software comprises one or more sets of executable instructions stored or otherwise tangibly embodied on a non-transitory computer-readable storage medium. The software may include instructions and specific data that, when executed by one or more processors, operate the one or more processors to perform one or more aspects of the above-described techniques. The non-transitory computer-readable storage medium may include, for example, magnetic or optical disk storage, flash memory, cache, solid-state storage such as random access memory (RAM), or other non-volatile memory devices. The executable instructions stored on the non-transitory computer-readable storage medium may be source code, assembly language code, object code, or other instruction formats interpretable or executable by one or more processors.

[0106] A computer-readable storage medium may include any storage medium or combination of storage media that can be accessed by a computer system to provide instructions and / or data to the computer system during use. Such storage media include, but are not limited to, optical media (e.g., compact discs (CDs), digital versatile discs (DVDs), Blu-ray discs), magnetic media (e.g., floppy disks, magnetic tape, magnetic hard drives), volatile memory (e.g., random access memory (RAM) or cache), non-volatile memory (e.g., read-only memory (ROM) or flash memory), or microelectromechanical systems (MEMS)-based storage media. A computer-readable storage medium may be embedded in a computer system (e.g., system RAM or ROM), permanently attached to a computing system (e.g., a magnetic hard drive), removably attached to a computing system (e.g., an optical disk or universal serial bus (USB)-based flash memory), or connected to a computer system via a wired or wireless network (e.g., a network-access storage device (NAS)).

[0107] It should be noted that not all of the activities or elements described in the general description above are required, that some of the specific activities or devices may not be required, and that one or more additional activities may be performed or elements may be included in addition to those described. Further, the order in which the activities are listed is not necessarily the order in which they are performed. Also, the concepts are described with reference to specific embodiments. However, those skilled in the art will recognize that various modifications and changes can be made without departing from the scope of the present disclosure, as set forth in the claims below. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present disclosure.

[0108] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, benefits, advantages, solutions to problems, and features by which the benefits, advantages, or solutions occur or become more pronounced should not be construed as critical, essential, or essential features of any or all claims. Moreover, the specific embodiments disclosed above are merely exemplary, and the disclosed subject matter may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. No limitations are intended to the details of construction or design shown herein, except as set forth in the following claims. It will therefore be apparent that the specific embodiments disclosed above may be altered or modified, and all such variations are considered within the scope of the disclosed subject matter. Accordingly, the protection sought herein is as set forth in the following claims.

Claims

1. 1. A method in a communications processor (500) of a cellular user equipment (UE) device (102) for detecting adverse radio link conditions, comprising: monitoring a plurality of layers (610) of a communication stack (608) of the UE device (102) during an active voice call (701), wherein an application processor (604) of the UE device (102) provides voice data (614) to one or more of the plurality of layers (610); Detecting at least one adverse wireless link condition associated with the active voice call (701) in response to monitoring (610) the plurality of layers; and providing a radio link degradation (RLD) indication (622) to the application processor (604) of the UE device (102) in response to detecting the at least one adverse radio link condition.

2. A method in a communications processor (500) of a cellular user equipment (UE) device (102) for detecting adverse radio link conditions, comprising: monitoring a plurality of layers (610) of a communication stack (608) of said UE device (102) during an active voice call (701); Detecting at least one adverse wireless link condition associated with the active voice call (701) in response to monitoring (610) the plurality of layers; and providing a radio link degradation (RLD) indication (622) to an application processor (604) of the UE device (102) in response to detecting the at least one adverse radio link condition; Detecting the at least one adverse wireless link condition comprises: Detecting signal strength updates (705) in response to monitoring (610) the plurality of layers; In response to detecting the signal strength update (705), accessing one or more signal-related characteristics (707) associated with the signal strength update (705); determining whether a value associated with any of said one or more signal-related characteristics (707) satisfies a corresponding threshold (709); determining that the at least one adverse wireless link condition exists in response to the value associated with any of the one or more signal-related characteristics (707) satisfying the corresponding threshold (709), wherein the method comprises: Whether transmission time interval (TTI) bundling is enabled in the UE device (102). and determining selecting the corresponding threshold (709) from a first threshold set (709-1) in response to TTI bundling being enabled; and in response to TTI bundling being disabled, selecting the corresponding threshold (709) from a second threshold set (709-2), the second threshold set being set lower than the first threshold set.

3. A method in a communications processor (500) of a cellular user equipment (UE) device (102) for detecting adverse radio link conditions, comprising: monitoring a plurality of layers (610) of a communication stack (608) of said UE device (102) during an active voice call (701); Detecting at least one adverse wireless link condition associated with the active voice call (701) in response to monitoring (610) the plurality of layers; and providing a radio link degradation (RLD) indication (622) to an application processor (604) of the UE device (102) in response to detecting the at least one adverse radio link condition; Detecting the at least one adverse wireless link condition comprises: determining a required bandwidth (1103) at a physical layer (610-1) of the plurality of layers (610) for current voice traffic on a downlink channel associated with the active voice call (701); determining a current throughput (1109) in a data path layer (610-2) of the plurality of layers (610) on a dedicated voice radio bearer associated with the active voice call (701); determining that a low performance state (1115) exists at the physical layer in response to the requested bandwidth (1103) being greater than the current throughput (1109); incrementing a low performance count (1113) in response to determining that a low performance condition (1115) exists; comparing the low function count to a low function count threshold (1117); The method of claim 1, wherein the RLD indication is provided to the application processor (604) in response to the low functionality count (1113) meeting the low functionality count threshold (1117).

4. A method in a communications processor (500) of a cellular user equipment (UE) device (102) for detecting adverse radio link conditions, comprising: monitoring a plurality of layers (610) of a communication stack (608) of said UE device (102) during an active voice call (701); Detecting at least one adverse wireless link condition associated with the active voice call (701) in response to monitoring (610) the plurality of layers; and providing a radio link degradation (RLD) indication (622) to an application processor (604) of the UE device (102) in response to detecting the at least one adverse radio link condition; Detecting the at least one adverse wireless link condition comprises: determining a bandwidth (1205) required for outgoing voice traffic associated with the active voice call (701) in a physical layer (610-1) of the plurality of layers (610); determining a currently achieved throughput (1207) at a data path layer (610-2) of said plurality of layers (610) on an uplink channel associated with said active voice call (701); determining that a low performance state (1213) exists in the physical layer (610-1) in response to the requested bandwidth (1205) being greater than the currently achieved throughput (1207).

5. A method in a communications processor (500) of a cellular user equipment (UE) device (102) for detecting adverse radio link conditions, comprising: monitoring a plurality of layers (610) of a communication stack (608) of said UE device (102) during an active voice call (701); Detecting at least one adverse wireless link condition associated with the active voice call (701) in response to monitoring (610) the plurality of layers; and providing a radio link degradation (RLD) indication (622) to an application processor (604) of the UE device (102) in response to detecting the at least one adverse radio link condition; Detecting the at least one adverse wireless link condition comprises: determining that a high transmit power deficit condition (1311) exists; and determining that a throughput (1319) of outgoing voice packets at a data path layer (610-2) of the plurality of layers (610) is less than a throughput (1321) of voice traffic generated at the data path layer (610-2) of the plurality of layers (610).

6. 6. The method of claim 1, wherein the RLD indication notifies the application processor that the at least one adverse radio link condition exists and identifies a cause of the at least one adverse radio link condition.

7. 7. The method of claim 1, wherein providing the RLD indication (622) comprises providing the RLD indication (622) to the application processor (604) during the active voice call (701).

8. The at least one detected adverse radio link condition is an out-of-sync condition (903), and providing the RLD indication (622) comprises: determining that a radio link failure (RLF) timer (905) has been started in response to the occurrence of the out-of-sync condition (903); and providing the RLF indication (622) to the application processor when the RLF timer (905) starts and before the RLF timer (905) expires.

9. that a synchronization condition (909) occurred while said RLF timer (905) was active; The RLF timer (905) has expired, or the RLF timer (905) has expired and the UE device (102) has successfully performed a Radio Resource Control (RRC) connection re-establishment procedure (911); in response to detecting one of 9. The method of claim 8, comprising resetting an RLD indication (622) maintained internally by the communications processor (500).

10. the at least one detected adverse wireless link condition is an out-of-sync condition (903); The method comprises: determining that a radio link failure (RLF) timer (905) has expired, the RLF timer (905) being started in response to the occurrence of the out-of-sync condition (903); The method comprises: determining that the UE device (102) has successfully performed a Radio Resource Control (RRC) connection re-establishment procedure (911) in response to the RLF timer (905) expiring; and resetting an RLD indication (622) maintained internally by the communications processor (500) in response to the RRC connection re-establishment procedure (911) being successful.

11. The at least one detected adverse radio link condition is a Radio Link Control (RLC) maximum retransmission condition (1005) associated with data traffic, and providing the RLC indication (622) comprises: determining that a radio link failure (RLF) has occurred due to the RLC maximum retransmission condition (1005); and providing the RLD indication (622) to the application processor (604) in response to the RLF.

12. determining that the UE device (102) has successfully completed a Radio Resource Control (RRC) connection re-establishment procedure (1007) in response to the RLF; determining whether other adverse radio link conditions (1009) exist in response to the successful completion of the RRC connection re-establishment procedure (1007); in response to the presence of at least one other adverse radio link condition (1009), providing an updated RLD indication (622) to the application processor (604) indicating that the at least one other adverse radio link condition (1009) exists and that the RLC maximum retransmission condition (1005) no longer exists; and resetting an RLD indication (622) maintained internally by the communications processor (500) in response to the absence of other adverse radio link conditions (1009).

13. 4. The method of claim 3, further comprising: resetting an RLD indication (622) maintained internally by the communications processor (500) indicating the presence of the at least one adverse radio link condition in response to the low functionality count (1113) not satisfying the low functionality count threshold (1117).

14. Detecting the at least one adverse wireless link condition comprises: incrementing a low performance count (1211) in response to determining that a low performance condition (1213) exists; comparing the low function count (1211) with a low function count threshold (1215); 5. The method of claim 4, wherein the RLD indication is provided to the application processor in response to the low functionality count meeting the low functionality count threshold.

15. 15. The method of claim 14, further comprising resetting an RLD indication (622) maintained internally by the communications processor (500) indicating the presence of the at least one adverse radio link condition in response to the low functionality count (1211) not satisfying the low functionality count threshold (1215).

16. Determining that a high transmit power deficit condition (1311) exists includes: Detecting a transmission power shortage (1303); comparing the transmit power deficit (1303) with a transmit power deficit threshold (1309); incrementing a high transmit power deficiency count (1313) in response to the transmit power deficiency (1303) meeting the transmit power deficiency threshold (1309); determining a proportion of high transmit power deficiency instances (1315) based on said high transmit power deficiency count (1313) for a monitoring window of a given number of transmission instances; determining that the high transmit power deficiency condition exists in response to the ratio of high transmit power deficiency instances meeting a ratio threshold.

17. monitoring the plurality of layers (610) of the communication stack (608) of the UE device (102) during the active voice call (701) includes monitoring at least one parameter across one or more of the plurality of layers of the communication stack, the at least one parameter being related to maintaining the active voice call; 17. The method of claim 1, wherein detecting the at least one adverse radio link condition associated with the active voice call (701) comprises detecting the at least one adverse radio link condition associated with the active voice call (701) based on the at least one parameter.

18. 20. The method of claim 17, wherein detecting the at least one adverse radio link condition associated with the active voice call (701) based on the at least one parameter comprises detecting the at least one adverse radio link condition in response to the at least one parameter satisfying a predetermined criterion.

19. The user equipment device (102) one or more radio frequency (RF) modems (306) configured to communicate wirelessly with at least one network (100); one or more processors (310) coupled to the one or more RF modems (306); and at least one memory (312) that stores executable instructions, the executable instructions configured to operate at least one of the one or more processors (310) or the one or more RF modems (306) to perform the method of any one of claims 1 to 18.

20. A program for causing a computer system (102) to execute the method according to any one of claims 1 to 18.

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