Patent Description:
Wireless communication systems are rapidly growing in usage. In recent years, wireless devices such as smart phones and tablet computers have become increasingly sophisticated. In addition to supporting telephone calls, many mobile devices now provide access to the internet, email, text messaging, and navigation using the global positioning system (GPS), and are capable of operating sophisticated applications that utilize these functionalities. Additionally, there exist numerous different wireless communication technologies and standards. Some examples of wireless communication standards include GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE Advanced (LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), IEEE <NUM> (WLAN or Wi-Fi), BLUETOOTH™, etc..

The ever-increasing number of features and functionality introduced in wireless communication devices also creates a continuous need for improvement in both wireless communications and in wireless communication devices. To increase coverage and better serve the increasing demand and range of envisioned uses of wireless communication, in addition to the communication standards mentioned above, there are further wireless communication technologies under development.

A proposed next telecommunications standard moving beyond the current International Mobile Telecommunications-Advanced (IMT-Advanced) Standards is called 5th generation mobile networks or 5th generation wireless systems, or <NUM> for short (otherwise known as <NUM>-NR for <NUM> New Radio, also simply referred to as NR). <NUM>-NR proposes a higher capacity for a higher density of mobile broadband users, also supporting device-to-device, ultra-reliable, and massive machine communications, as well as lower latency and lower battery consumption, than current LTE standards. Further, the <NUM>-NR standard may allow for less restrictive UE scheduling as compared to current LTE standards. Consequently, efforts are being made in ongoing developments of <NUM>-NR to take advantage of higher throughputs possible at higher frequencies. Accordingly, improvements in the field in support of such development and design are desired.

<CIT> discloses various methods performed by a network node in a radio communication network, including detecting a radio link failure on a master cell group and indicating to a user equipment whether to use a master cell group fast recovery procedure to avoid a radio resource control re-establishment.

<NPL>, discusses fast recovery mechanisms in case of a handover/reconfiguration with sync failure.

Embodiments relate to wireless communications, and more particularly to apparatuses, systems, and methods for enhanced radio link failure recovery.

A user equipment (UE) may establish a radio resource control (RRC) connection with a first cell of a cellular network and transmit signaling comprising an indication of enhanced radio link failure (RLF) recovery capability. The UE may receive one or more RRC messages comprising configuration information for RLF recovery on the first cell. The UE detect one or more RLFs corresponding to the first cell and further determine, via a connection reestablishment cell selection procedure, that the first cell is a suitable RLF recovery candidate cell. In response to the detection and determination, the UE may apply the configuration information for the first cell. The UE may then transmit signaling comprising a trigger indicating a RLF recovery to the cellular network and re-establish the RRC connection with the cellular network using the configuration information.

In some embodiments, the first cell may include a primary cell (PCell) to which the UE was connected to prior to the one or more RLFs and the one or more candidate cells may include one or more neighboring cells. Additionally or alternatively, the signaling comprising the trigger further may comprise at least one of a reason for the enhanced RLF recovery, an identifier of the applied configuration information, a cause of the RLF, information data regarding the RLF, and/or a RLF report, among various possibilities. According to some embodiments, the signaling comprising the trigger indicating a RLF recovery may be transmitted via media access control (MAC) layer-<NUM> (L2) signaling.

In some embodiments, upon successful reception of the trigger, user-plane data transfer between the UE and at least one of the serving cell and one or more candidate cells may be resumed. Additionally or alternatively, the configuration information may include one or more enhanced RLF recovery configurations associated with the serving cell. According to some embodiments, each of the one or more enhanced RLF recovery configurations may correspond to one or more distinct validity periods configured by the base station.

In some embodiments, the one or more candidate cells may include a primary cell (PCell) to which the UE may have been connected to prior to the one or more RLFs and may further be configured by the network as a candidate CHO cell. Additionally or alternatively, the one or more candidate cells may be configured by the network as one or more candidate CHO cells. According to some embodiments, the LTE or wireless device may be configured to indicate support of an enhanced radio link failure (RLF) recovery capability via non-access stratum (NAS) signaling. Additionally or alternatively, the signaling including the trigger indicating a RLF recovery may be transmitted via dedicated RRC signaling.

According to further embodiments, the CHO configuration information may include conditional execution conditions. Additionally or alternatively, the conditional execution conditions may be configured by the base station in an Abstract Syntax Notation <NUM>(ASN. <NUM>) field.

In some embodiments, a base station may configure one or more validity periods corresponding to the configuration information and the base station may be configured to dynamically enable or disable the enhanced RLF recovery capability of the UE. Additionally or alternatively, the base station may be configured to indicate via System Information Broadcast (SIB) messaging whether or not the enhanced RLF capability is allowed.

The techniques described herein may be implemented in and/or used with a number of different types of devices, including but not limited to unmanned aerial vehicles (UAVs), unmanned aerial controllers (UACs), base stations, access points, cellular phones, tablet computers, wearable computing devices, portable media players, automobiles and/or motorized vehicles, and any of various other computing devices.

Accordingly, it will be appreciated that the above-described features are merely examples.

While the features described herein may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to be limiting to the particular form disclosed.

Memory Medium - Any of various types of non-transitory memory devices or storage devices. The term "memory medium" is intended to include an installation medium, e.g., a CD-ROM, floppy disks, or tape device; a computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash, magnetic media, e.g., a hard drive, or optical storage; registers, or other similar types of memory elements, etc. The memory medium may include other types of non-transitory memory as well or combinations thereof. In addition, the memory medium may be located in a first computer system in which the programs are executed, or may be located in a second different computer system which connects to the first computer system over a network, such as the Internet. In the latter instance, the second computer system may provide program instructions to the first computer for execution. The term "memory medium" may include two or more memory mediums which may reside in different locations, e.g., in different computer systems that are connected over a network. The memory medium may store program instructions (e.g., embodied as computer programs) that may be executed by one or more processors.

Computer System (or Computer) - any of various types of computing or processing systems, including a personal computer system (PC), mainframe computer system, workstation, network appliance, Internet appliance, personal digital assistant (PDA), television system, grid computing system, or other device or combinations of devices. In general, the term "computer system" can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

User Equipment (UE) (or "UE Device") - any of various types of computer systems devices which are mobile or portable and which performs wireless communications. Examples of UE devices include mobile telephones or smart phones (e.g., iPhone™, Android™-based phones), portable gaming devices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™, iPhone™), laptops, wearable devices (e.g. smart watch, smart glasses), PDAs, portable Internet devices, music players, data storage devices, other handheld devices, automobiles and/or motor vehicles, unmanned aerial vehicles (UAVs) (e.g., drones), UAV controllers (UACs), and so forth. In general, the term "UE" or "UE device" can be broadly defined to encompass any electronic, computing, and/or telecommunications device (or combination of devices) which is easily transported by (or with) a user and capable of wireless communication.

Processing Element (or Processor) - refers to various elements or combinations of elements that are capable of performing a function in a device, such as a user equipment or a cellular network device. Processing elements may include, for example: processors and associated memory, portions or circuits of individual processor cores, entire processor cores, processor arrays, circuits such as an ASIC (Application Specific Integrated Circuit), programmable hardware elements such as a field programmable gate array (FPGA), as well any of various combinations of the above.

Various components may be described as "configured to" perform a task or tasks.

The communication area (or coverage area) of the base station may be referred to as a "cell. " The base station 102A and the UEs <NUM> may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-Advanced (LTE-A), <NUM> new radio (5GNR), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc. Note that if the base station 102A is implemented in the context of LTE, it may alternately be referred to as an 'eNodeB' or 'eNB'. Note that if the base station 102A is implemented in the context of <NUM> NR, it may alternately be referred to as 'gNodeB' or 'gNB'.

In some embodiments, base station 102A may be a next generation base station, e.g., a <NUM> New Radio (<NUM> NR) base station, or "gNB". In some embodiments, a gNB may be connected to a legacy evolved packet core (EPC) network and/or to a NR core (NRC) network. In addition, a gNB cell may include one or more transmission and reception points (TRPs).

Note that a UE <NUM> may be capable of communicating using multiple wireless communication standards. For example, the UE <NUM> may be configured to communicate using a wireless networking (e.g., Wi-Fi) and/or peer-to-peer wireless communication protocol (e.g., Bluetooth, Wi-Fi peer-to-peer, etc.) in addition to at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, SGNR, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc.). The UE <NUM> may also or alternatively be configured to communicate using one or more global navigational satellite systems (GNSS, e.g., GPS or GLONASS), one or more mobile television broadcasting standards (e.g., ATSC-M/H or DVB-H), and/or any other wireless communication protocol, if desired. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

<FIG> illustrates user equipment <NUM> (e.g., one of the devices 106A through 106N) in communication with a base station <NUM> and an access point <NUM>, according to some embodiments. The UE <NUM> may be a device with both cellular communication capability and non-cellular communication capability (e.g., Bluetooth, Wi-Fi, and so forth) such as a mobile phone, a handheld device, a computer or a tablet, or virtually any type of wireless device.

The UE <NUM> may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, the UE <NUM> may be configured to communicate using, for example, CDMA2000 (1xRTT / 1xEV-DO / HRPD / eHRPD), LTE/LTE-Advanced, or <NUM> NR using a single shared radio and/or GSM, LTE, LTE-Advanced, or <NUM> NR using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g., for MIMO) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g., for digital modulation as well as other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE <NUM> may share one or more parts of a receive and/or transmit chain between multiple wireless communication technologies, such as those discussed above.

<FIG> illustrates an exemplary block diagram of an access point (AP) <NUM>. It is noted that the block diagram of the AP of <FIG> is only one example of a possible system. As shown, the AP <NUM> may include processor(s) <NUM> which may execute program instructions for the AP <NUM>. The processor(s) <NUM> may also be coupled (directly or indirectly) to memory management unit (MMU) <NUM>, which may be configured to receive addresses from the processor(s) <NUM> and to translate those addresses to locations in memory (e.g., memory <NUM> and read only memory (ROM) <NUM>) or to other circuits or devices.

The AP <NUM> may include at least one network port <NUM>. The network port <NUM> may be configured to couple to a wired network and provide a plurality of devices, such as UEs <NUM>, access to the Internet. For example, the network port <NUM> (or an additional network port) may be configured to couple to a local network, such as a home network or an enterprise network. For example, port <NUM> may be an Ethernet port. The local network may provide connectivity to additional networks, such as the Internet.

The AP <NUM> may include at least one antenna <NUM>, which may be configured to operate as a wireless transceiver and may be further configured to communicate with UE <NUM> via wireless communication circuitry <NUM>. The antenna <NUM> communicates with the wireless communication circuitry <NUM> via communication chain <NUM>. Communication chain <NUM> may include one or more receive chains, one or more transmit chains or both. The wireless communication circuitry <NUM> may be configured to communicate via Wi-Fi or WLAN, e.g., <NUM>. The wireless communication circuitry <NUM> may also, or alternatively, be configured to communicate via various other wireless communication technologies, including, but not limited to, <NUM> NR, Long-Term Evolution (LTE), LTE Advanced (LTE-A), Global System for Mobile (GSM), Wideband Code Division Multiple Access (WCDMA), CDMA2000, etc., for example when the AP is co-located with a base station in case of a small cell, or in other instances when it may be desirable for the AP <NUM> to communicate via various different wireless communication technologies.

In some embodiments, as further described below, an AP <NUM> may be configured to perform methods for overhead reduction for multi-carrier beam selection and power control as further described herein.

The network port <NUM> may be configured to couple to a telephone network and provide a plurality of devices, such as UE devices <NUM>, access to the telephone network as described above in <FIG> and <FIG>.

The core network may provide mobility related services and/or other services to a plurality of devices, such as LTE devices <NUM>.

<FIG> illustrates an example block diagram of a server <NUM>, according to some embodiments. It is noted that the server of <FIG> is merely one example of a possible server. As shown, the server <NUM> may include processor(s) <NUM> which may execute program instructions for the server <NUM>.

The server <NUM> may be configured to provide a plurality of devices, such as base station <NUM>, UE devices <NUM>, and/or UTM <NUM>, access to network functions, e.g., as further described herein.

In some embodiments, the server <NUM> may be part of a radio access network, such as a <NUM> New Radio (5GNR) radio access network. In some embodiments, the server <NUM> may be connected to a legacy evolved packet core (EPC) network and/or to a NR core (NRC) network.

As described further subsequently herein, the server <NUM> may include hardware and software components for implementing or supporting implementation of features described herein. The processor <NUM> of the server <NUM> may be configured to implement or support implementation of part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition) the processor <NUM> of the server <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, and/or <NUM> may be configured to implement or support implementation of part or all of the features described herein.

<FIG> illustrates an example simplified block diagram of a communication device <NUM>, according to some embodiments. It is noted that the block diagram of the communication device of <FIG> is only one example of a possible communication device. According to embodiments, communication device <NUM> may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet, an unmanned aerial vehicle (UAV), a UAV controller (UAC) and/or a combination of devices, among other devices. As shown, the communication device <NUM> may include a set of components <NUM> configured to perform core functions. For example, this set of components may be implemented as a system on chip (SOC), which may include portions for various purposes. Alternatively, this set of components <NUM> may be implemented as separate components or groups of components for the various purposes. The set of components <NUM> may be coupled (e.g., communicatively; directly or indirectly) to various other circuits of the communication device <NUM>.

Note that the term "SIM" or "SIM entity" is intended to include any of various types of SIM implementations or SIM functionality, such as the one or more UICC(s) cards <NUM>, one or more eUICCs, one or more eSIMs, either removable or embedded, etc. In some embodiments, the UE <NUM> may include at least two SIMs. Each SIM may execute one or more SIM applications and/or otherwise implement SIM functionality. Thus, each SIM may be a single smart card that may be embedded, e.g., may be soldered onto a circuit board in the UE <NUM>, or each SIM may be implemented as a removable smart card. Thus, the SIM(s) may be one or more removable smart cards (such as UICC cards, which are sometimes referred to as "SIM cards"), and/or the SIMs <NUM> may be one or more embedded cards (such as embedded UICCs (eUICCs), which are sometimes referred to as "eSIMs" or "eSIM cards"). In some embodiments (such as when the SIM(s) include an eUICC), one or more of the SIM(s) may implement embedded SIM (eSIM) functionality; in such an embodiment, a single one of the SIM(s) may execute multiple SIM applications. Each of the SIMs may include components such as a processor and/or a memory; instructions for performing SIM/eSIM functionality may be stored in the memory and executed by the processor. In some embodiments, the UE <NUM> may include a combination of removable smart cards and fixed/non-removable smart cards (such as one or more eUICC cards that implement eSIM functionality), as desired. For example, the UE <NUM> may comprise two embedded SIMs, two removable SIMs, or a combination of one embedded SIMs and one removable SIMs. Various other SIM configurations are also contemplated.

As noted above, in some embodiments, the UE <NUM> may include two or more SIMs. The inclusion of two or more SIMs in the UE <NUM> may allow the UE <NUM> to support two different telephone numbers and may allow the UE <NUM> to communicate on corresponding two or more respective networks. For example, a first SIM may support a first RAT such as LTE, and a second SIM support a second RAT such as <NUM> NR. Other implementations and RATs are of course possible. In some embodiments, when the UE <NUM> comprises two SIMs, the UE <NUM> may support Dual SIM Dual Active (DSDA) functionality. The DSDA functionality may allow the UE <NUM> to be simultaneously connected to two networks (and use two different RATs) at the same time, or to simultaneously maintain two connections supported by two different SIMs using the same or different RATs on the same or different networks. The DSDA functionality may also allow the UE <NUM> to simultaneously receive voice calls or data traffic on either phone number. In certain embodiments the voice call may be a packet switched communication. In other words, the voice call may be received using voice over LTE (VoLTE) technology and/or voice over NR (VoNR) technology. In some embodiments, the UE <NUM> may support Dual SIM Dual Standby (DSDS) functionality. The DSDS functionality may allow either of the two SIMs in the UE <NUM> to be on standby waiting for a voice call and/or data connection. In DSDS, when a call/data is established on one SIM, the other SIM is no longer active. In some embodiments, DSDx functionality (either DSDA or DSDS functionality) may be implemented with a single SIM (e.g., a eUICC) that executes multiple SIM applications for different carriers and/or RATs.

As shown, the SOC <NUM> may include processor(s) <NUM>, which may execute program instructions for the communication device <NUM> and display circuitry <NUM>, which may perform graphics processing and provide display signals to the display <NUM>. The processor(s) <NUM> may also be coupled to memory management unit (MMU) <NUM>, which may be configured to receive addresses from the processor(s) <NUM> and translate those addresses to locations in memory (e.g., memory <NUM>, read only memory (ROM) <NUM>, NAND flash memory <NUM>) and/or to other circuits or devices, such as the display circuitry <NUM>, short to medium range wireless communication circuitry <NUM>, cellular communication circuitry <NUM>, connector I/F <NUM>, and/or display <NUM>. The MMU <NUM> may be configured to perform memory protection and page table translation or set up. In some embodiments, the MMU <NUM> may be included as a portion of the processor(s) <NUM>.

As noted above, the communication device <NUM> may be configured to communicate using wireless and/or wired communication circuitry. The communication device <NUM> may be configured to perform methods for beam failure recovery based on a unified TCI framework, e.g., in <NUM> NR systems and beyond, as further described herein.

As described herein, the communication device <NUM> may include hardware and software components for implementing the above features for a communication device <NUM> to communicate a scheduling profile for power savings to a network. The processor <NUM> of the communication device <NUM> may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor <NUM> may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor <NUM> of the communication device <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be configured to implement part or all of the features described herein.

Further, as described herein, cellular communication circuitry <NUM> and short to medium range wireless communication circuitry <NUM> may each include one or more processing elements. In other words, one or more processing elements may be included in cellular communication circuitry <NUM> and, similarly, one or more processing elements may be included in short to medium range wireless communication circuitry <NUM>. Thus, cellular communication circuitry <NUM> may include one or more integrated circuits (ICs) that are configured to perform the functions of cellular communication circuitry <NUM>. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of cellular communication circuitry <NUM>. Similarly, the short to medium range wireless communication circuitry <NUM> may include one or more ICs that are configured to perform the functions of short to medium range wireless communication circuitry <NUM>. In addition, each integrated circuit may include circuitry (e.g., first circuitry, second circuitry, etc.) configured to perform the functions of short to medium range wireless communication circuitry <NUM>.

<FIG> illustrates an example simplified block diagram of cellular communication circuitry, according to some embodiments. It is noted that the block diagram of the cellular communication circuitry of <FIG> is only one example of a possible cellular communication circuit. According to embodiments, cellular communication circuitry <NUM>, which may be cellular communication circuitry <NUM>, may be included in a communication device, such as communication device <NUM> described above. As noted above, communication device <NUM> may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet and/or a combination of devices, among other devices.

The cellular communication circuitry <NUM> may couple (e.g., communicatively; directly or indirectly) to one or more antennas, such as antennas 435a-b and <NUM> as shown (in <FIG>). In some embodiments, cellular communication circuitry <NUM> may include dedicated receive chains (including and/or coupled to, e.g., communicatively; directly or indirectly. For example, as shown in <FIG>, cellular communication circuitry <NUM> may include a modem <NUM> and a modem <NUM>. Modem <NUM> may be configured for communications according to a first RAT, e.g., such as LTE or LTE-A, and modem <NUM> may be configured for communications according to a second RAT, e.g., such as 5GNR.

LTL front end <NUM> may include circuitry for transmitting radio signals via antenna <NUM>.

In some embodiments, the cellular communication circuitry <NUM> may be configured to perform methods beam failure recovery based on a unified TCI framework, e.g., in 5GNR systems and beyond, as further described herein.

As described herein, the modem <NUM> may include hardware and software components for implementing the above features or for time division multiplexing UL data for NSA NR operations, as well as the various other techniques described herein. The processors <NUM> may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor <NUM> may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> may be configured to implement part or all of the features described herein.

As described herein, the modem <NUM> may include hardware and software components for implementing the above features for communicating a scheduling profile for power savings to a network, as well as the various other techniques described herein. The processors <NUM> may be configured to implement part or all of the features described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), processor <NUM> may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition) the processor <NUM>, in conjunction with one or more of the other components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> may be configured to implement part or all of the features described herein.

In some implementations, fifth generation (<NUM>) wireless communication will initially be deployed concurrently with current wireless communication standards (e.g., LTE). For example, dual connectivity between LTE and <NUM> new radio (<NUM> NR or NR) has been specified as part of the initial deployment of NR. Thus, as illustrated in <FIG>, evolved packet core (EPC) network <NUM> may continue to communicate with current LTE base stations (e.g., eNB <NUM>). In addition, eNB <NUM> may be in communication with a <NUM> NR base station (e.g., gNB <NUM>) and may pass data between the EPC network <NUM> and gNB <NUM>. Thus, EPC network <NUM> may be used (or reused) and gNB <NUM> may serve as extra capacity for LTEs, e.g., for providing increased downlink throughput to UEs. In other words, LTE may be used for control plane signaling and NR may be used for user plane signaling. Thus, LTE may be used to establish connections to the network and NR may be used for data services.

<FIG> illustrates a proposed protocol stack for eNB <NUM> and gNB <NUM>. As shown, eNB <NUM> may include a medium access control (MAC) layer <NUM> that interfaces with radio link control (RLC) layers 622a-b. RLC layer 622a may also interface with packet data convergence protocol (PDCP) layer 612a and RLC layer 622b may interface with PDCP layer 612b. Similar to dual connectivity as specified in LTE-Advanced Release <NUM>, PDCP layer 612a may interface via a master cell group (MCG) bearer with EPC network <NUM> whereas PDCP layer 612b may interface via a split bearer with EPC network <NUM>.

Additionally, as shown, gNB <NUM> may include a MAC layer <NUM> that interfaces with RLC layers 624a-b. RLC layer 624a may interface with PDCP layer 612b of eNB <NUM> via an X<NUM> interface for information exchange and/or coordination (e.g., scheduling of a UE) between eNB <NUM> and gNB <NUM>. In addition, RLC layer 624b may interface with PDCP layer <NUM>. Similar to dual connectivity as specified in LTE-Advanced Release <NUM>, PDCP layer <NUM> may interface with EPC network <NUM> via a secondary cell group (SCG) bearer. Thus, eNB <NUM> may be considered a master node (MeNB) while gNB <NUM> may be considered a secondary node (SgNB). In some scenarios, a UE may be required to maintain a connection to both an MeNB and a SgNB. In such scenarios, the MeNB may be used to maintain a radio resource control (RRC) connection to an EPC while the SgNB may be used for capacity (e.g., additional downlink and/or uplink throughput).

<FIG> illustrates an example of a baseband processor architecture for a UE (e.g., such as UE <NUM>), according to some embodiments. The baseband processor architecture <NUM> described in <FIG> may be implemented on one or more radios (e.g., radios <NUM> and/or <NUM> described above) or modems (e.g., modems <NUM> and/or <NUM>) as described above. As shown, the non-access stratum (NAS) <NUM> may include a <NUM> NAS <NUM> and a legacy NAS <NUM>. The legacy NAS <NUM> may include a communication connection with a legacy access stratum (AS) <NUM>. The <NUM> NAS <NUM> may include communication connections with both a <NUM> AS <NUM> and a non-3GPP AS <NUM> and Wi-Fi AS <NUM>. The <NUM> NAS <NUM> may include functional entities associated with both access stratums. Thus, the <NUM> NAS <NUM> may include multiple <NUM> MM entities <NUM> and <NUM> and <NUM> session management (SM) entities <NUM> and <NUM>. The legacy NAS <NUM> may include functional entities such as short message service (SMS) entity <NUM>, evolved packet system (EPS) session management (ESM) entity <NUM>, session management (SM) entity <NUM>, EPS mobility management (EMM) entity <NUM>, and mobility management (MM)/ GPRS mobility management (GMM) entity <NUM>. In addition, the legacy AS <NUM> may include functional entities such as LTE AS <NUM>, UMTS AS <NUM>, and/or GSM/GPRS AS <NUM>.

Thus, the baseband processor architecture <NUM> allows for a common <NUM>-NAS for both <NUM> cellular and non-cellular (e.g., non-3GPP access). Note that as shown, the <NUM> MM may maintain individual connection management and registration management state machines for each connection. Additionally, a device (e.g., UE <NUM>) may register to a single PLMN (e.g., <NUM> CN) using <NUM> cellular access as well as non-cellular access. Further, it may be possible for the device to be in a connected state in one access and an idle state in another access and vice versa. Finally, there may be common <NUM>-MM procedures (e.g., registration, de-registration, identification, authentication, as so forth) for both accesses.

Note that in various embodiments, one or more of the above described functional entities of the 5GNAS and/or <NUM> AS may be configured to perform methods overhead reduction for multi-carrier beam selection and power control, e.g., as further described herein.

In the scenario in which a user equipment (UE) has established a connection with the network (e.g., a base station or evolved node-B (eNB)/next-generation node-B (gNB)), the UE may be considered to be in a radio resource control (RRC) connected mode. However, if the UE experiences a radio link failure (RLF), the UE may execute a connection re-establishment procedure. More specifically, if a suitable cell is found during connection re-establishment cell selection, the LTE may exchange sequences of over-the-air messages with the cellular network to resume the connection. For example, <FIG> illustrates a connection re-establishment procedure in response to a radio link failure (RLF), according to some embodiments.

A UE may experience a RLF due to various physical layer issues, expiry of one or more timers (e.g., T310 timer), or if the UE has reached a maximum number of random access reconnection attempts. More specifically, some UEs may experience radio link failures due to temporary out-of-coverage scenarios in which the UE may enter an area having minimal cellular coverage. Accordingly, the minimal cellular coverage (e.g., minimal carrier signal strength) may result in the primary serving cell "Pcell" being lost during this time. For example, some UEs may experience this loss of the Pcell due to entering an elevator, going into house basement, or entering a tunnel, among other examples. During this period of connection reestablishment, the UE user-plane data transfer with the network may be suspended.

Once the temporary out-of-coverage scenario has been resolved (e.g., the user and/or LTE has exited a house basement, evaluator, or tunnel), the UE may attempt to reconnect to the network. During the connection re-establishment cell selection procedure, the UE may re-select the same primary serving cell "Pcell" that it was previously using or camping on before it experienced the RLF. However, the UE may still have to perform appropriate connection re-establishment procedures which may be unnecessarily time consuming.

For example, as shown in <FIG>, a cellular device <NUM> (e.g., a UE) may establish a connection with a first serving cell (e.g., a primary cell (PCell)) corresponding to a cellular network <NUM>. Accordingly, the UE may be considered to be in an RRC Connected state <NUM> and may further experience or detect a radio link failure (RLF) <NUM> corresponding to issues discussed above. In <NUM>, the UE may attempt to initiate a connection re-establishment with the network and further release some of the connected mode configurations (e.g., releasing secondary cells (Scells)). Moreover, after the UE has performed cell selection in <NUM>, the UE may prepare to send a reestablishment request to the network by applying layer-<NUM> (L1) and media access control (MAC) default configurations in <NUM>. Accordingly, the UE and network may exchange RRC-messages such as a RRC re-establishment request <NUM> message, a RRC re-establishment <NUM> message, a RRC re-establishment complete <NUM> message, a RRC reconfiguration <NUM> message, and a RRC reconfiguration complete <NUM> message as part of corresponding operations as defined in appropriate 3GPP specifications and standards.

Additionally, the RRC Reconfiguration air-messages may provide and/or include complete or partial PCell and Scells configurations. Moreover, radio link control (RLC) and packet data convergence protocol (PDCP) radio-bearer re-establishment may be required in order to complete the connection re-establishment procedure. In new radio (NR), these operations could take up to <NUM>. For example, the operations involving the UE releasing its configurations and applying default configurations may take up to <NUM>, the RRC processing delay requirements for the RRC re-establishment complete <NUM> message may take up to <NUM> and the RRC processing delay requirements for the RRC re-configuration complete <NUM> message may take up to <NUM> for a total of approximately <NUM>.

In long term evolution (LTE), these operations could take up to <NUM>. For example, the operations involving the UE releasing its configurations and applying default configurations may take up to <NUM>, the RRC processing delay requirements for the RRC re-establishment complete <NUM> message may take up to <NUM> and the RRC processing delay requirements for the RRC reconfiguration complete <NUM> message may take up to <NUM> for a total of approximately <NUM>. Accordingly, by performing the operations similar to the ones discussed above, the UE may experience an unnecessary time in which the UE user-plane data transfer with the network may be suspended.

Embodiments described herein provide mechanisms for enhanced radio link failure recovery. For example, some non-claimed examples may involve a UE performing a connection reestablishment cell selection procedure in which the UE selects the same primary serving cell "Pcell" that it was connected to or camping on before a RLF was detected or occurred. According to the claims the UE as an alternative to re-performing the connection re-establishment procedure described above, instead stops the connection re-establishment procedure and sends a special trigger to the network. According to some embodiments, the trigger may be RRC dedicated signaling air-message or layer-<NUM> (L2) media access control (MAC) layer signaling. Additionally or alternatively, once the special trigger is successfully received by the network and results in a successful random access procedure, the connection may be considered to be re-established. Accordingly, the user-plane data transfer, which was initially suspended upon the occurrence of the RLF and loss of the Pcell connection, may be immediately resumed with the reception of the enhanced RLF recovery special trigger at the network. In other words, the user-plane data transfer may be able to be resumed at the point within the random access procedure described above in regard to <FIG> corresponding to the UE applying layer-<NUM> (L1) and media access control (MAC) default configurations in <NUM>. Accordingly, the UE may be able to re-establish its user-plane data transfer with the network without experiencing the <NUM> and <NUM> delays associated with performing the complete connection re-establishment procedures associated with <NUM>-<NUM> of <FIG>.

<FIG> illustrates a high-level flow diagram of an enhanced RLF recovery procedure, according to some embodiments.

Aspects of the method of <FIG> may be implemented by a wireless device, such as the UE(s) <NUM>, in communication with one or more base stations (e.g., BS <NUM>) as illustrated in and described with respect to the Figures, or more generally in conjunction with any of the computer systems or devices shown in the Figures, among other circuitry, systems, devices, elements, or components shown in the Figures, among other devices, as desired. For example, one or more processors (or processing elements) of the UE (e.g., processor(s) <NUM>, baseband processor(s), processor(s) associated with communication circuitry, etc., among various possibilities) may cause the UE to perform some or all of the illustrated method elements. Note that while at least some elements of the method are described in a manner relating to the use of communication techniques and/or features associated with 3GPP specification documents, such description is not intended to be limiting to the disclosure, and aspects of the method may be used in any suitable wireless communication system, as desired. In various embodiments, some of the elements of the methods shown may be performed concurrently, in a different order than shown, may be substituted for by other method elements, or may be omitted. Additional method elements may also be performed as desired. As shown, the method may operate as follows.

For example, as shown in <FIG>, a cellular device <NUM> (e.g., a UE) may establish a connection with a cellular network cell (e.g., a first cell or PCell) <NUM> such that the UE is considered to be in an RRC connected state <NUM>, according to some embodiments.

In <NUM>, the UE <NUM> may indicate to the network <NUM> of its capability regarding enhanced RLF recovery. For example, the UE may transmit a radio resource control (RRC) message to the network indicating that its enhanced RLF recovery feature is supported, according to some embodiments. In some embodiments, the UE may indicate the support of this feature to the network through UE Capability Information (e.g., through non-access stratum (NAS) or RRC layers UE Capability dedicated signaling air-messages).

In <NUM>, the network may, through secured dedicated signaling (e.g., over-the-air RRC messages) enable an enhanced RLF recovery feature in which connected mode configurations may be applied after RLF recovery on the Pcell (e.g., the first cell). Additionally or alternatively, it may be determined by the network how the scope of connected mode configurations (e.g., common or dedicated) are applied before the RLF such that the UE may re-use said configurations after the RLF recovery. Accordingly, the user-plane data transfer (e.g., at least on the Pcell/first cell) may be immediately resumed regardless of whether a partial set of the configurations (e.g., the network may send another RRC Reconfiguration over-the-air message after RLF recovery) has been applied or full set of configurations have been applied. According to some embodiments, the network may dynamically, within the RRC connection, enable and disable this enhanced RLF recovery feature in the UE through dedicated signaling air-messages (e.g., RRC dedicated signaling air messages).

According to some embodiments in which the feature is enabled, the network may configure the UE with a validity period for the enhanced RLF recovery configurations. More specifically, the validity period for the enhanced RLF recovery configurations may correspond to a time period in which the UE considers the corresponding configurations to be valid configurations. In other words, the corresponding configurations may only be validly applied by the UE if the validity period has not exceeded a threshold. According to some embodiments, the network may associate more than one enhanced RLF recovery configurations within the same Pcell such that each configuration may correspond to a different and distinct validity period. According to some embodiments, the network cell may indicate if this validity period feature is supported or not supported through System Information Broadcast messages parameters (e.g., SIB1 parameters).

In some embodiments, if the RRC Connected mode configurations configured before the RLF are not fully re-used by the UE after an RLF recovery, the network may configure the UE with the difference or delta of configurations (e.g., partial configurations) such that the current Pcell configurations or full (e.g., complete) connected mode configurations (common or dedicated), may be applied by the UE after the enhanced RLF recovery.

In <NUM>, the UE may detect a radio link failure (RLF) potentially corresponding to a temporary out-of-coverage scenarios in which the UE has entered an area having minimal cellular coverage. Accordingly, this may result in the primary serving cell "Pcell" being lost during this time and before the connection is reestablished, the UE user-plane data transfer with the network may be suspended.

In <NUM>, the UE may initiate a connection re-establishment procedure by performing cell selection <NUM>. More specifically, the UE may select a suitable cell (e.g., a cell in which the UE may obtain normal service) based on idle mode measurements and certain cell selection criteria. For example, the cell may part of a selected or registered public land mobile network (PLMN) and the UE may scan radio-frequency (RF) channels in the NR or LTE radio interface (e.g., Evolved Universal Terrestrial Radio Access (E-UTRA)). According to some embodiments, the UE may only search for the strongest cell on each carrier frequency and once a suitable cell is found this cell may be selected by the UE. In other words, the LTE may determine, via the connection reestablishment cell selection procedure, that the first cell (e.g., the Pcell to which it was camped on before the RLF) is a suitable RLF recovery candidate cell. According to some embodiments, the UE may then apply, in response to detecting the one or more RLFs and determining that the first cell is a suitable RLF recovery candidate cell, the configuration information for the first cell.

In <NUM>, if the selected Pcell is the first cell that the UE was connected to or camping on previously, the UE may transmit a special trigger to the network (e.g., via RRC signaling over-the-air messaging), according to some embodiments. Accordingly, upon successful reception of the special trigger at the network, the user-plane data transfer may be resumed and such that data may once again be exchanged between the network and UE. Additionally or alternatively, the connection re-establishment special trigger transmitted from the UE to the network may provide the network with additional information. For example, the trigger may include an indication that the reason for the transmitted special trigger pertains to an enhanced RLF recovery procedure. In some embodiments, the trigger may include an identifier for the applied enhanced RLF recovery configuration in the scenario in which more than one was configured. Additionally or alternatively, the trigger may include information regarding the cause of the RLF as well as any further data that could be associated with the RLF (e.g., signal strength measurements) and/or any other information defined by 3GPP.

Accordingly, during connection re-establishment, if the selected cell was the previous Pcell the UE was camping on before the RLF occurred (which is typical in temporary out-of-coverage scenarios) and most of the RRC Connected mode configurations have been applied (and could be re-used) before the RLF, then the NR and LTE connection re-establishment operations could be reduced from <NUM> and <NUM> respectively to approximately two milliseconds which may correspond to the time required to initiate and transmit the enhanced RLF recovery trigger to the network. Moreover, this technique may be applied for different cellular technologies other than LTE and NR or any future cellular technologies.

<FIG> illustrates an example flow diagram of an enhanced RLF recovery procedure using enhanced RLF recovery radio resource control (RRC) reconfiguration messages, according to some embodiments. More specifically, <FIG> illustrates a method in which the network may configure the UE with one or more enhanced RLF recovery RRC reconfiguration encoded over-the-air messages associated with candidate Pcells such as the current Pcell (e.g., previously connected to and/or camped on) or other candidate Pcells (e.g., neighboring cells) through a RRC Reconfiguration procedure.

Similar to <NUM> as discussed above in regard to <FIG>, in <NUM> a cellular device <NUM> (e.g., a UE) may establish a connection with a cellular network cell (e.g., a PCell/first cell) <NUM> such that the UE is considered to be in an RRC connected state <NUM>, according to some embodiments.

In <NUM>, the network may transmit an inquiry to the UE regarding the UE's capability or support of enhanced RLF recovery procedures. In other words, the network may request information from the UE so that the network may assist the UE in performing said enhanced RLF recovery procedures (if the UE indicates it is capable) if a RLF is encountered.

In <NUM>, the UE may transmit, in response to receiving the inquiry from the network in <NUM>, a response to the network which may include information regarding the UE's capability or support of enhanced RLF recovery procedures. More specifically, the UE may indicate support of this feature through a RRC UECapabilityInformation air-message.

Furthermore, an example code block regarding the UE's capability information in <NUM> may correspond to:
SEQUENCE {. enhancedRlfRecovery-ReconfiogSupport
{supported}, optional Need N,.

In <NUM> the network may, in response to receiving the UE's capability information, transmit one or more RRC reconfiguration messages to the UE in order to assist or prepare the UE for an enhanced recovery procedure upon encountering an RLF. For example, one or more enhanced RLF recovery RRC reconfiguration messages transmitted from the network to the UE may include a difference or delta of configurations (e.g., a partial configuration) from the current UE RRC Connected mode common or dedicated configurations. Moreover, the network may determine the content of the enhanced RLF recovery RRC reconfiguration. For example, the network may require the UE to re-use most of the RRC Connected mode configurations (e.g., common or dedicated) in which they would be applied before the RLF occurs. Accordingly, the message content may have minimal information due to the re-use of configurations and/or information elements (IEs) such as MobilityControlInformation IE in LTE or ReconfigurationWithSync IE in NR. Furthermore, information about the candidate enhanced RLF recovery Pcell, such as frequency and physical cell identity, may not be required for the enhanced RLF recovery RRC reconfiguration message for the current Pcell. In other words, this information may already be known to the UE and therefore including this information in the message may not be useful for the UE. Additionally or alternatively, the network may include other configurations up to complete full connected mode configurations. In some embodiments, a normal (e.g., a non-enhanced RLF recovery RRC reconfiguration message) RRC reconfiguration message may be received at any point in time during the RRC connected state. According to some embodiments, an example code block of the RRC reconfiguration message may correspond to:
SEQUENCE {. enhancedRlfRecoveryAddModList: :=SEQUENCE(SIZE(<NUM>. maxenhancedRlfecoveryCells)) OF
enhancedRlfRecoveryToAddMod
enhancedRlfRecoveryAddMod::=SEQUENCE{
enhancedRlfRecoveryId enhancedRlfRecoveryid. enhancedRlfRecoveryReconfig OCTET
STRING(CONTAINING RRCReconfiguration) OPTIONAL,--Cond
validity enhancedRlfRecoveryValidityperiod
OPTIONAL,--Cond enhancedRlfRecoveryAdd.

In <NUM> the UE may, in response to receiving the RRC reconfiguration message from the network, transmit a RRC reconfiguration complete message upon successful completion of the random access procedure.

In <NUM>, the UE may initiate a connection re-establishment procedure. However, in contrast to the typical connection reestablishment shown in <FIG>, the UE may not release the connected mode configurations (e.g., Scells) and proceed directly to cell selection <NUM> which may involve a procedure similar to that of <NUM> from <FIG>.

In <NUM>, if the connection re-establishment selected cell was one of the candidate enhanced RLF recovery primary serving cells (Pcells) (e.g., the same Pcell the UE was connected to or camping on before the RLF, the UE may stop the connection re-establishment procedure as indicated by <NUM>, apply the associated stored enhanced RLF recovery RRC Reconfiguration message in <NUM>, and send an RRC ReconfigurationComplete message accordingly in <NUM>. Accordingly, at this point in time in which the Random Access Procedure has been successful and the RRC Reconfiguration Complete message has been sent to the network, the user-plane data may be resumed. According to some embodiments, this procedure may be similar to an intra-RAT handover. In some embodiments, the Random Access configurations may be provided within the associated enhanced RLF recovery RRC reconfiguration message. Additionally or alternatively, if the Random Access configurations are not provided, the UE may use the Random Access configurations broadcast in the selected Pcell system information blocks (SIBs).

In some embodiments, the network may be able to dynamically enable and/or disable the enhanced RLF recovery feature through a new abstract syntax notation <NUM> (ASN. <NUM>) field in the dedicated RRC Reconfiguration air-message (e.g., the "enhancedRlfReconveryReconfigAddList" ASN. <NUM> field). Moreover, the entries in the list for a candidate Enhanced RLF Recovery Pcell may include information such as an identifier (ID) for the enhanced RLF recovery configuration entry, according to some embodiments. Additionally or alternatively, the entries in the list for a candidate Enhanced RLF Recovery Pcell may include EnhancedRlfRecoveryReconfig which may be an encoded RRC Reconfiguration message that could be applied if the connection re-establishment selected cell is included within this message. In some embodiments, the entries in the list for a candidate Enhanced RLF Recovery Pcell may include cell information such as frequency and physical cell ID which would be part of this message. For example, in NR, this cell information may be part of the ReconfigurationWithSync ASN. <NUM> information element.

According to some embodiments, the entries in the list for a candidate Enhanced RLF Recovery Pcell may include a validity period corresponding to a time period for the configuration validity. More specifically, this validity period may start or be initiated after the RLF has been detected by the UE. If this period elapsed or expired (e.g., exceeded a threshold value), there may be different configurations options possible that are configurable by the network. For example, as one option, the UE may discard this configuration entry. Additionally or alternatively, the UE may apply a certain and/or minimal set of configurations that are defined by 3GPP specifications. For example, if the time elapsed since the RLF was detected by the UE is greater than the ValidityPeriod value but less than certain threshold, the UE may release one or more corresponding Scells and apply specific values and/or default values for other configurations. One advantage of this may be that the user-plane data transfer could be immediately resumed after sending a RRC Reconfiguration Complete message rather than having to wait for the next RRC Reconfiguration message to be received from the network (e.g., as is the case in the normal connection reestablishment procedure).

According to some embodiments, the network may configure the UE with multiple entries for the same candidate enhanced RLF recovery Pcell with different validity periods and content. For example, this may be advantageous in the scenario in which the network may require the UE to apply different configurations if the UE was unable to apply a configuration if the ValidityPeriod was exceeded by a value less than certain threshold. In other words, the UE may be able to apply configurations with smaller validity periods first and configurations with larger validity periods subsequently, according to some embodiments.

In some embodiments, the network may indicate through System Information Broadcast messages (e.g., SIB1 parameter,) if the enhanced RLF recovery feature is supported/allowed or not. Furthermore, in the RRC ReconfigurationComplete message sent by the UE to the network for enhanced RLF recovery, the UE may include information such as a reason or indication for performing the enhanced RLF recovery procedure. Additionally or alternatively, the UE may include information regarding the ID of the applied enhanced RLF recovery configuration which may be required if the UE is configured with more than one enhanced RLF recovery configuration for the same Pcell.

In some embodiments, the UE may include information such as the cause of the RLF as well as any information or data regarding the RLF. Additionally or alternatively, the UE may include other information that may be defined by 3GPP specifications such as parameters uemeasurmentsAvailable and rlf-InfoAvailable. More specifically, the UE may indicate rlf-InfoAvailable in the RRC ReconfigurationComplete message. Accordingly, the network may, in response, trigger a UEInformationRequest or UEInformationResponse to retrieve a RLF report, which may include the cause of the RLF and/or other RLF-related information. Once the RRC Reconfiguration Complete message is received by the network, the connection may be considered re-established and the user-plane data transfer may be able to be resumed after the random access procedure successful completion or at the point within the random access procedure described above in regard to <FIG> corresponding to the UE applying layer-<NUM> (L1) and media access control (MAC) default configurations in <NUM>. Accordingly, the UE may be able to re-establish its user-plane data transfer with the network without experiencing the <NUM> and <NUM> delays associated with performing the complete connection re-establishment procedures associated with <NUM>-<NUM> from <FIG>.

<FIG> illustrates an example flow diagram of an enhanced RLF recovery procedure by extending the existing framework used for conditional handovers (CHOs), according to some embodiments.

As shown in <FIG> and similar to <NUM> as discussed above in regard to <FIG>, a cellular device <NUM> (e.g., a UE) may establish a connection with a cellular network cell (e.g., a PCell/first cell) <NUM> such that the UE is considered to be in an RRC connected state <NUM>, according to some embodiments.

In <NUM>, the network may transmit one or more RRC reconfiguration messages to the UE in order to assist or prepare the UE for an enhanced recovery procedure upon encountering an RLF. According to some embodiments, the network may configure the UE with a list of candidate CHO PCells that the UE may use for triggering a CHO if certain configured conditions (e.g., conditional execution conditions) are fulfilled. Additionally or alternatively, the network may trigger CHO execution if the selected cell during the connection re-establishment cell selection procedure is one of the configured candidate CHO PCells. In some embodiments, the conditional execution conditions may be configured by the condExecutionCond ASN. <NUM> field in NR. However, this may not be applicable if the CHO candidate Pcell is the current Pcell as fulfilling conditional execution conditions as described above may not be applied on the current Pcell. Accordingly, quick re-camping via CHO execution on the previous Pcell during the connection re-establishment procedure may not be possible.

According to some embodiments, the conditional executions conditions may correspond to a new event characterized similarly to the serving cell's signal quality becoming worse than a threshold (e.g., EventA2). This new event may be utilized rather than considering a neighboring cell's signal quality offset becoming better than the SpCell's signal quality (e.g., EventA3) and/or the SpCell's signal quality becoming worse than a first threshold and the neighboring cell signal quality becoming better than a second threshold (e.g., EventA5). Accordingly, fulfilling certain conditional execution conditions such as these may lead to early triggering of an RLF recovery procedure.

Additionally or alternatively, the network may configure the current Pcell (e.g., the first cell of which the UE may be connected to or camped on) such that it is one of the conditional reconfiguration candidate Pcells. In other words, the current Pcell may be also configured by the network as a CHO candidate Pcell. In some embodiments, a normal (e.g., a non-enhanced RLF recovery RRC reconfiguration message) RRC reconfiguration message may be received at any point in time during the RRC connected state. More specifically, an example code block of the RRC reconfiguration message may correspond to:
SEQUENCE{. CondReconfigToAddMod-r16 ::= SEQUENCE{
condReconfigId-r16. CondReconfigId-r16,
condExecutionCond-r16 SEQUENCE (SIZE(<NUM>. <NUM>)) OF MeasId OPTIONAL, --Cond
condReconfigAddPcell
condRRCReconfig-r16 OCTET STRING (CONTAINING RRCReconfiguration) OPTIONAL, -
Cond condReconfigAdd.

According to some embodiments, for master cell group (MCG) candidate Pcells other than the current Pcell or for secondary cell group (SCG) candidate Pscells, the condReconfigAddPcell field may be required to be present when a conditional reconfiguration ID is being added. In some embodiments, if the condReconfigAddPcell field is optional, need M. Additionally or alternatively, if the MCG candidate Pcell is equivalent to the current Pcell, the condReconfigAddPcell field may be absent.

In <NUM>, if the connection re-establishment is initiated and the selected cell during connection re-establishment is one of the configured candidate CHO Pcells, then the UE may stop the connection re-establishment procedure in <NUM> and apply the stored conditional reconfiguration message to the Pcell (e.g., the first cell the UE was connected to). Similar to a typical CHO execution, this may initiate a CHO procedure on the selected Pcell. Accordingly, the corresponding CHO may utilize normal intra-RAT handover procedures in which the applied RRC Reconfiguration message is the one stored in the UE for the corresponding selected conditional reconfiguration candidate Pcell that was previously configured by the network (e.g., the Pcell the UE was camping on or connected to before the RLF). In some embodiments, a NR capable UE may initiate the CHO execution by applying the associated CHO RRC Reconfiguration message set in condReconfig ASN. <NUM> field associated with the previous Pcell CHO conditional reconfiguration entry.

In <NUM>, having successfully executed the CHO, the UE may transmit a RRC ReconfigurationComplete message to the network. Additionally or alternatively, the UE may include information in the RRC Reconfiguration Complete message to the network regarding whether or not the enhanced RLF recovery procedure was successful or achieved, the cause of the RLF and/or other information regarding the RLF or defined by 3GPP specifications (e.g., uemeasurmentsAvailable, rlf-InfoAvailable). In some embodiments and similar to other CHO RRC Reconfiguration messages, the RRC Reconfiguration message may include a mobility IE (e.g., MobilityControlInformation IE in LTE or reconfigurationWithSync IE in NR). Accordingly, a normal intra-RAT handover procedure may be followed for re-establishing the connection in which a random access procedure would be applied to re-access the cell. Moreover, once the RRC Reconfiguration Complete message is received by the network, the connection may be considered to be re-established. In other words, the user-plane data transfer may be able to be resumed at the point within the random access procedure described above in regard to <FIG> corresponding to the UE applying layer-<NUM> (L1) and media access control (MAC) default configurations in <NUM>. Accordingly, the UE may be able to re-establish its user-plane data transfer with the network without experiencing the <NUM> and <NUM> delays associated with performing the complete connection re-establishment procedures associated with <NUM>-<NUM>.

In some embodiments, a device (e.g., a UE <NUM>) may be configured to include a processor (or a set of processors) and a memory medium, where the memory medium stores program instructions, where the processor is configured to read and execute the program instructions from the memory medium, where the program instructions are executable to implement any of the various method embodiments described herein (or, any combination of the method embodiments described herein, or, any subset of any of the method embodiments described herein, or, any combination of such subsets). The device may be realized in any of various forms.

Claim 1:
A method, comprising:
by a user equipment, UE (<NUM>):
establish (<NUM>) a radio resource control, RRC, connection with a first cell (<NUM>) of a cellular network;
transmit (<NUM>), to the cellular network, signaling comprising an indication that an enhanced radio link failure, RLF, recovery capability is supported, wherein the enhanced RLF recovery capability comprises applying connected mode configurations after RLF recovery on the first cell;
receive (<NUM>), from the cellular network, one or more RRC messages comprising configuration information for RLF recovery on the first cell;
detect (<NUM>) one or more RLFs corresponding to the first cell;
determine (<NUM>), via a connection reestablishment cell selection procedure, that the first cell is a suitable RLF recovery candidate cell of one or more candidate cells;
apply (<NUM>), in response to detecting the one or more RLFs and determining that the first cell is a suitable RLF recovery candidate cell, the configuration information for RLF recovery on the first cell;
in response to applying the configuration information, transmit (<NUM>), to the cellular network, signaling comprising a trigger indicating an enhanced RLF recovery; and
re-establish, upon successful reception of the trigger at the cellular network and without exchanging additional signaling with the cellular network as part of a complete RRC connection re-establishment procedure, the RRC connection with the cellular network using the configuration information.