WO2020227842A1

WO2020227842A1 - Apparatus and methods for reducing impact of malfunction in user equipments

Info

Publication number: WO2020227842A1
Application number: PCT/CN2019/086324
Authority: WO
Inventors: Haojun WANG; Zhenqing CUI; Hong Wei
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2019-05-10
Filing date: 2019-05-10
Publication date: 2020-11-19
Anticipated expiration: 2021-11-10

Abstract

Aspects of the present disclosure provide techniques and apparatus for wireless communication. In one aspect, a method is provided which may be performed by a wireless device such as a user equipment (UE) that may support a first type of radio access technology (RAT) and a second type of RAT. The method generally includes: sending an attach request message comprising an indication of support for a first connection mode to a network entity, the first connection mode comprising connections to both the first type of RAT and the second type of RAT; receiving a first response message from a first base station (BS) of the first type of RAT, the first response message sent in response to the attach request message and comprising an indication of addition of a cell of the second type of RAT; connecting to a second BS of the cell of the second type of RAT, in response to receiving the response message; sending a message indicating connection complete to the first BS; exchanging information with the second BS, in response to sending the message indicating connection complete; losing communication with the second BS due to an event related to a component of the UE associated with the second type of RAT, while exchanging the information with the second BS; and taking action in response to losing the communication with the second BS.

Description

APPARATUS AND METHODS FOR REDUCING IMPACT OF MALFUNCTION IN USER EQUIPMENTS

Technical Field

The present disclosure relates generally to wireless communications, and more particularly, to apparatus and methods for reducing impact of malfunction in user equipments (UEs) .

BACKGROUND

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) . 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra reliable low latency communications (URLLC) . Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in LTE or 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In an aspect of the disclosure, methods, computer-readable media, and apparatuses are provided. The apparatuses may be user equipment (UE) or a base station (BS) . Certain aspects of the present disclosure provide a method for wireless communications, performed by a wireless device, such as a user equipment (UE) . The UE may support a first type of radio access technology (RAT) and a second type of RAT. The method generally includes: sending an attach request message comprising an indication of support for a first connection mode to a network entity, the first connection mode comprising connections to both the first type of RAT and the second type of RAT; receiving a first response message from a first base station (BS) of the first type of RAT, the first response message sent in response to the attach request message and comprising an indication of addition of a cell of the second type of RAT; connecting to a second BS of the cell of the second type of RAT, in response to receiving the first response message; sending a message indicating connection complete to the first BS, in response to connecting to the second BS; exchanging information with the second BS, in response to sending the message indicating connection complete; losing communication with the second BS due to an event related to a component of the UE associated with the second type of RAT, while exchanging the information with the second BS; and taking action in response to losing the communication with the second BS.

Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus may comprise a UE, and may support a first type of radio access technology (RAT) and a second type of RAT. The apparatus generally includes at least one processor configured/capable of being configured to, or configured/capable of being configured to direct the apparatus to: send an attach request message comprising an indication of support for a first connection mode to a network entity, the first connection mode comprising connections to both the first type of RAT and the second type of RAT; receive a first response message from a first base station (BS) of the first type of RAT, the first response message sent in response to the attach request message and comprising an indication of addition of a cell of the second type of RAT; connect to a second BS of the cell of the second type of RAT, in response to receiving the first response message; send a message indicating connection complete to the first BS, in response to connecting to the second BS; exchange information with the second BS, in response to sending the message indicating connection complete; lose communication with the second BS due to an event related to a component of the UE associated with the second type of RAT, while exchanging the information with the second BS; and take action in response to losing the communication with the second BS, and memory coupled to the at least one processor.

Certain aspects of the present disclosure provide for an apparatus for wireless communication. The apparatus may comprise a UE, and may support a first type of radio access technology (RAT) and a second type of RAT. The apparatus generally includes: means for sending an attach request message comprising an indication of support for a first connection mode to a network entity, the first connection mode comprising connections to both the first type of RAT and the second type of RAT; means for receiving a first response message from a first base station (BS) of the first type of RAT, the first response message sent in response to the attach request message and comprising an indication of addition of a cell of the second type of RAT; means for connecting to a second BS of the cell of the second type of RAT, in response to receiving the first response message; means for sending a message indicating connection complete to the first BS, in response to connecting to the second BS; means for exchanging information with the second BS, in response to sending the message indicating connection complete; means for losing communication with the second BS due to an event related to a component of the UE associated with the second type of RAT, while exchanging the information with the second BS; and means for taking action in response to losing the communication with the second BS.

Certain aspects of the present disclosure provide for a computer-readable medium for wireless communication by a wireless device, such as a UE. The computer-readable medium may comprise a non-transitory computer-readable medium. The wireless device may support a first type of radio access technology (RAT) and a second type of RAT. The computer-readable medium generally includes code, which when executed by at least one processor, causes the wireless device to: send an attach request message comprising an indication of support for a first connection mode to a network entity, the first connection mode comprising connections to both the first type of RAT and the second type of RAT; receive a first response message from a first base station (BS) of the first type of RAT, the first response message sent in response to the attach request message and comprising an indication of addition of a cell of the second type of RAT; connect to a second BS of the cell of the second type of RAT, in response to receiving the first response message; send a message indicating connection complete to the first BS, in response to connecting to the second BS; exchange information with the second BS, in response to sending the message indicating connection complete; lose communication with the second BS due to an event related to a component of the UE associated with the second type of RAT, while exchanging the information with the second BS; and take action in response to losing the communication with the second BS.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network, in accordance with certain aspects of the present disclosure.

FIGs. 2A, 2B, 2C, and 2D are diagrams illustrating examples of a first 5G/NR frame, DL channels within a 5G/NR subframe, a second 5G/NR frame, and UL channels within a 5G/NR subframe, respectively, in accordance with certain aspects of the present disclosure.

FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network, in accordance with certain aspects of the present disclosure.

FIG. 4 illustrates an example structure for dual connectivity, in accordance with certain aspects of the present disclosure.

FIG. 5 illustrates an example flow diagram, in accordance with certain aspects of the present disclosure.

FIG. 6 illustrates an example flow diagram, in accordance with certain aspects of the present disclosure.

FIG. 7 illustrates an example flow diagram, in accordance with certain aspects of the present disclosure.

FIG. 8 illustrates example operations, e.g., by a UE, in accordance with certain aspects of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using hardware, software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and a 5G Core (5GC) 190. The base stations 102 may include macro cells (high power cellular base station) and/or small cells (low power cellular base station) . The macro cells include base stations. The small cells include femtocells, picocells, and microcells. The term “cell” can refer to, for example, a coverage area of a BS and/or a BS or BS subsystem serving this coverage area, depending on the context in which the term is used. The term “channel” can refer to, for example, a channel in which information is carried, or the information carried on the channel, depending on the context in which the term is used.

The base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through backhaul links 132 (e.g., S1 interface) . The base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN) ) may interface with 5GC 190 through backhaul links 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or 5GC 190) with each other over backhaul links 134 (e.g., X2 interface) . The backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102' may have a coverage area 110' that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y megahertz (MHz) (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102' may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102' , employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. A base station 102, whether a small cell 102' or a large cell (e.g., macro base station) , may include an eNB, gNodeB (gNB) , or other type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW /near mmW radio frequency band (e.g., 3 GHz –300 GHz) has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range.

The base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182' . The UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 182” . The UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions. The base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 180 /UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180 /UE 104. The transmit and receive directions for the base station 180 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The 5GC 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 104 and the 5GC 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved Node B (eNB) , an access point, a node, a network node, a network element, a device, a wireless device, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or 5GC 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a netbook, a smartbook, a personal digital assistant (PDA) , a robots/robotic device, a drone, industrial manufacturing equipment, a satellite radio, a navigation/positioning device (e.g., GNSS (global navigation satellite system) devices based on, for example, GPS (global positioning system) , Beidou, GLONASS, or Galileo, a terrestrial-based device, etc. ) , a multimedia device, an entertainment device, a video device, a digital audio player (e.g., MP3 player) , a camera, a gaming device, a tablet, a smart device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, virtual reality goggles, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet) ) , a vehicle, a vehicular device, a meter (e.g., parking meter, electric meter, gas meter, water meter) , a monitor, a gas pump, an appliance (e.g., kitchen appliance, washing machine, dryer) , a location tag, a medical/healthcare device, an implant, a sensor/actuator, a display, or any other suitable device configured to communicate via a wireless or wired medium. Machine type communication (MTC) may refer to communication involving at least one remote device on at least one end of the communication and may include forms of data communication which involve one or more entities that do not necessarily need human interaction. MTC UEs may include UEs that are capable of MTC communications with, e.g., MTC servers and/or other MTC devices through Public Land Mobile Networks (PLMN) , for example. Wireless devices may include Internet-of-Things (IoT) devices (e.g., narrowband IoT (NB-IoT) devices) . IoT may refer to a network of physical objects, devices, or “things” . IoT devices may be embedded with, for example, electronics, processing units, software, or sensors and may have network connectivity, which enable these devices to collect and exchange data. Some of the UEs 104 may be referred to as IoT devices (e.g., meters, gas pumps, toasters, robots, drones, vehicles, heart monitors, etc. ) .

IoT devices may be sensed and controlled remotely across existing network infrastructure, creating opportunities for more direct integration between the physical world and computer-based systems and resulting in improved efficiency, accuracy, and economic benefit. Systems that include IoT devices augmented with sensors and actuators may be referred to cyber-physical systems. Cyber-physical systems may include technologies such as smart grids, smart homes, intelligent transportation, and/or smart cities. Each “thing” (e.g., IoT device) may be uniquely identifiable through its embedded computing system may be able to interoperate within existing infrastructure, such as Internet infrastructure.

IoT UEs may include MTC/enhanced MTC (eMTC, also referred to as CAT-M, Cat M1) UEs, NB-IoT (also referred to as CAT NB1) UEs, as well as other types of UEs. In the present disclosure, eMTC and NB-IoT may refer to future technologies that may evolve from or may be based on these technologies. For example, eMTC may include FeMTC (further eMTC) , eFeMTC (enhanced further eMTC) , mMTC (massive MTC) , etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT) , FeNB-IoT (further enhanced NB-IoT) , etc.

The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a device, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Referring again to FIG. 1, in certain aspects, UE 104 may perform communication (198) with at least one base station (e.g., BS 102/180) . Base station 102/180 may support and be part of both a first type of RAT and a second type of RAT and may be configured to send at least one signal associated with the communication 198. The communication 198 may be associated with action performed by the UE to: scan for the first type of RAT, connecting to BS 102/180 of the first type of RAT, or transitioning from the second type of RAT to the first type of RAT.

FIG. 2A is a diagram 200 illustrating an example of a first subframe within a 5G/NR frame structure. FIG. 2B is a diagram 230 illustrating an example of DL channels within a 5G/NR subframe. FIG. 2C is a diagram 250 illustrating an example of a second subframe within a 5G/NR frame structure. FIG. 2D is a diagram 280 illustrating an example of UL channels within a 5G/NR subframe. The 5G/NR frame structure may be FDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be TDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided by FIGs. 2A, 2C, the 5G/NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL) , where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 being configured with slot format 34 (with mostly UL) . While

subframes

3, 4 are shown with slot formats 34, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) . Note that the description infra applies also to a 5G/NR frame structure that is TDD.

Other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms) . Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission) . The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies μ0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2 ^μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2 ^μ*15 kKz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kilohertz (kHz) and the numerology μ=5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIGs. 2A-2D provide an example of slot configuration 0 with 14 symbols per slot and numerology μ=0 with 1 slot per subframe. The subcarrier spacing is 15 kHz and symbol duration is approximately 66.7 μs.

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot) signals (RS) for the UE.The RS may include demodulation RS (DMRS) (indicated as R _x for one particular configuration, where 100x is the port number, but other DMRS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .

FIG. 2B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DMRS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block. The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in FIG. 2C, some of the REs carry DMRS (indicated as R for one particular configuration, but other DMRS configurations are possible) for channel estimation at the base station. The UE may transmit DMRS for the physical uplink control channel (PUCCH) and DMRS for the physical uplink shared channel (PUSCH) . The PUSCH DMRS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DMRS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. Although not shown, the UE may transmit sounding reference signals (SRS) . The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 2D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing, or maybe used by controller/processor 359 to determine whether UE 350 is in coverage or remains in coverage of base station 310. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations. Controllers/processors and/or other components/modules/elements at UE 350 and may direct, coordinate, attempt or perform operations, flows, processes, and/or activities in connection with UE 350, for example, those illustrated in FIGs. 5, 6, 7 and/or FIG. 8. Controllers/processors and/or other components/modules/elements at BS 310 and may direct, coordinate, attempt, or perform operations, flows, processes, and/or activities in connection with BS 310.

The focus of traditional RAT design (e.g., for non-MTC devices) is on the improvement of spectral efficiency, ubiquitous coverage, and enhanced quality of service (QoS) support. For example, current LTE system downlink (DL) and uplink (UL) link budgets are designed for coverage of high end devices, such as state-of-the-art smartphones and tablets, which may support a relatively large DL and UL link budget.

However, as described above, one or more UEs in the wireless communication network (e.g., wireless communication network 100) may be devices that have limited communication resources, such as narrowband UEs, as compared to other (wideband) devices in the wireless communication network. For narrowband UEs, various requirements may be relaxed as only a limited amount of information may need to be exchanged. For example, maximum bandwidth may be reduced (relative to wideband UEs) , a single receive radio frequency (RF) chain may be used, peak rate may be reduced (e.g., a maximum of 100 bits for a transport block size) , transmit power may be reduced, Rank 1 transmission may be used, and half duplex operation may be performed.

In some cases, if half-duplex operation is performed, MTC UEs may have a relaxed switching time to transition from transmitting to receiving (or receiving to transmitting) . For example, the switching time may be relaxed from 20μs for regular UEs to 1ms for MTC UEs. For example, LTE Release 12 MTC UEs may still monitor downlink (DL) control channels in the same way as regular UEs, for example, monitoring for wideband control channels in the first few symbols (e.g., PDCCH) as well as narrowband control channels occupying a relatively narrowband, but spanning a length of a subframe (e.g., enhanced PDCCH or ePDCCH) .

For 5G deployment/commercialization, some operators may prefer to support non-stand alone E-UTRA-NR Dual Connectivity (EN-DC) mode first, for example, based on cost and time to market. FIG. 4 illustrates an example structure 400 for dual connectivity, in accordance with certain aspects of the present disclosure. While 4G LTE and 5G NR are used in the example of FIG. 4, the techniques disclosed herein may be applied to other RATs as well. The example of FIG. 4 includes a fusion solution that may be used, for example, starting at an earlier stage of 5G deployment/commercialization. UE 402, which may comprise UE 104/350, may include an applications processor (AP) , 4G LTE component, and 5G NR component. The AP, 4G LTE component, and 5G NR component may be integrated into a single chip or chip set, or may each be implemented as its own chip or chipset, or may be implemented as a combination of chips or chip sets. For example, the 4G LTE component and 5G NR component may be implemented as a single chip or chip set and the AP may be implemented as a separate chip or chip set. The 4G LTE and 5G NR components may include hardware, software, or combinations thereof. Hardware and/or software components, such as one or more components associated with 5G NR (e.g., hardware and/or software) may malfunction (e.g., crash, freeze, reset, etc. ) and lead to a reboot or restart of the one or more components or the entire UE, causing delays in 5G NR services on the UE (for example, a reboot or restart of the one or more components or the entire UE may take seconds, e.g., 10-30 seconds in certain configurations) , which may impact end user experience, especially for applications that require low latency, as an example, gaming, real-time video chat, etc. In accordance with certain aspects of the present disclosure, techniques are provided that enable UE functionality such as data services to continue to be used even during a 5G component reboot or restart, thereby enhancing end user experience.

EN-DC allows a UE (e.g., UE 402) to exchange information with a 5G NR gNB (e.g., gNB 406, which may comprise BS 102/180/310) with simultaneous connection with a LTE eNB (e.g., eNB 404, which may comprise BS 102/180/310) . In such a dual connectivity mode, while transfer of information is split between LTE and 5G NR, control of the dual connectivity is handled by the eNB. eNB may be referred to as the master node (MN) , or be part of a master cell group (MCG) , which may comprise more than one cell. gNB may be referred to as the secondary node (SN) , or be part of a secondary cell group (SCG) , which may comprise more than one cell. For example, when UE 402 needs to exchange information with the network, it establishes a connection with the LTE network. If UE 402 indicates support for EN-DC, eNB 404 may direct UE 402 to make NR measurements. If NR is found, eNB 404 may communicate with gNB 406 and provide gNB406 parameters to establish a connection with UE 402. When 5G NR connection set up is confirmed, eNB 404 may start forwarding at least a portion of information for UE 402 (e.g., user data) to gNB 406 for transmission to UE 402, or eNB 404 may request EPC 408 (which may comprise EPC 160) to directly exchange information for UE 402 (e.g., user data) with UE 402. eNB 404 and gNB 406 may be implemented as, or integrated into, a single base station (e.g., physically and/or virtually) that supports both LTE and 5G NR, or may be implemented as separate base stations (e.g., physically and/or virtually) .

In the example of FIG. 4, 5G non-standalone architecture Option 3, which uses the LTE core network (EPC 408) , is illustrated. Option 3 may comprise three modes/options/sub-options/features: option 3, option 3A, option 3X. For option 3, all user data from and to the network may flow through eNB 404, which determines to forward at least a portion of the user data to gNB 406, for example, via an X2 interface. In option 3, gNB 406 may not be configured to communicate with EPC 408 directly. For option 3A, both eNB 404 and gNB 406 may communicate directly with EPC 408 but may not directly communicate with each other. For option 3X, user data for UE 402 may flow directly to gNB 406 and then from gNB 406 to UE 402. At least a portion of the user data may be forwarded to eNB 404, for example, over a X2 interface, and then to UE 402. User data may also flow from EPC 408 directly to eNB 404. For example, user data for applications with relaxed latency requirements (e.g., voice, streaming audio, utility metering, text messages) may flow to eNB 404 from EPC 408, while user data for applications with strict latency requirements (e.g., real-time online gaming, vehicle communications, remote control of vehicles/drones, financial transactions) may flow to gNB 406 from EPC 408.

FIG. 5 illustrates an example flow diagram, in accordance with certain aspects of the present disclosure. The UE, LTE eNB, 5G NR gNB, and EPC of FIG. 5 may comprise, respectively, UE 402, eNB 404, gNB 406, and EPC 408 of FIG. 4. At label 1, UE 402 may power on. After power on, UE 402 may acquire and camp on LTE as an anchor, for example, by completing a connection procedure to eNB 404.

At label 2, UE 402 may send an attach request message comprising an indication of support for a first connection mode to EPC 408, the first connection mode may comprise connections to both a first type of RAT (e.g., LTE) and a second type of RAT (e.g., 5G NR) . The attach request message may be generated by a component of UE 402 associated with LTE (e.g., a 4G/LTE modem or chipset) . The first connection mode may comprise EN-DC. The indication of support for the first connection mode may be via a parameter (such as parameter DCNR (dual connectivity NR) with a value of 1) .

At label 3, UE 402 may receive a first response message from eNB 404. The first response message may be sent by LTE MCG network via eNB 404. The first response message may be sent in response to the attach request message and may comprise an indication of addition of a cell of 5G NR (e.g., cell of gNB 406) . The first response message may comprise a RRC connection reconfiguration message. As part of the addition procedure of the 5G NR cell, eNB 404 may direct UE 402 to make NR measurements, and if NR signals are found, eNB 404 may communicate with gNB 406 and provide gNB406 parameters to establish a connection with UE 402.

At label 4, UE 402 may connect to gNB 404, in response to receiving the response message. The connecting to gNB 404 may comprise UE 402 camping onto gNB 404 and/or performing random access with gNB 404. After connecting to gNB 404, UE 402 may be considered to be in EN_DC mode.

At label 5, UE 402 may send a message indicating connection complete to eNB 404. The message may comprise a RRC connection reconfiguration complete message.

At label 6, UE 402 may exchange information with gNB 406, in response to sending the message indicating connection complete. For example, AP 410 of UE 402 may exchange the information (e.g., user data) with eNB 404 (MCG) or gNB 406 (SCG) , either directly or indirectly, based at least in part on an operation mode (e.g., modes/options/sub-options/features 3, 3X, or 3A) and/or a network strategy. The network strategy may be based on factors such as latency requirements of applications, quality of service (QoS) , number of UEs accessing the network, etc.

At label 7, UE 402 may lose communication with gNB 406 due to an event related to a component of the UE associated with 5G NR, while exchanging the information with gNB 406. The event may comprise a malfunction of 5G NR component 414 of UE 402 (e.g., 5G NR modem or chipset) . The malfunction may be caused by a hardware and/or software crash, freeze, reset, infinite loop, etc. LTE component 412 of UE 402 may report a failure (e.g., SCG failure) as it cannot communicate with 5G NR component 414.

At label 8, UE 402 may not be able to use services (e.g., user data related services) until the malfunction has been resolved, so that UE 402 can attach/connect again. The malfunction may be resolved, for example, by re-initiating the malfunctioning component. The re-initiating may comprise rebooting, resetting, or reconfiguring. In addition, UE 402 may need to restart if the malfunctioning component is re-initiated. User may not be able to use data service, and if UE 402 is restarted, user may not be able to use UE 402, until the malfunctioning component or UE 402 is restarted, impacting user experience.

According to certain aspects of the present disclosure, techniques are provided so that user may continue to use data service during re-initiating of the malfunctioning component of a UE related to a RAT (e.g., 5G NR component 414) .

FIG. 6 illustrates an example flow diagram, in accordance with certain aspects of the present disclosure. The UE, LTE eNB, 5G NR gNB, and EPC of FIG. 6 may comprise, respectively, UE 402, eNB 404, gNB 406, and EPC 408 of FIG. 4. In the example of FIG. 6, labels 1 to 7 may be the same as or similar to corresponding labels of FIG. 5.

In the example of FIG. 6, UE 402 may take action in response to losing communication with gNB 406.

At label 8, UE 402 (as an example, 5G NR component 414, or AP 410) may send a first indication of the event to LTE component 412 of UE 402. The first indication may indicate reset/reboot/reconfiguration status of 5G NR component to LTE component 412 (as an example, using a user-defined signal/parameter/variable/flag, such as 5g_crash_ind_to_4G) . In response to or associated with sending the first indication of the event, UE 402 may re-initiate 5G NR component 414. The re-initiating may comprise at least one of: reconfiguring, rebooting, restarting, or resetting.

At label 9, UE 402 (as an example, LTE component 412) may determine whether a measurement event is configured for the 5G NR RAT. If the measurement event is configured based on the determination, UE 402 (as an example, LTE component 412) may send a first measurement report for the cell of the 5G NR RAT to eNB 404. The measurement report may indicate a signaling environment for the 5G NR RAT that is below a first threshold (e.g., a measurement report indicating or is associated with event A2) .

At label 10, UE 402 (as an example, LTE component 412) may start a first timer in response to sending the first measurement report. The timer may be a user-defined signal/parameter/variable/flag, such as Trelease. The timer may be set to count to a specific time based on application requirements, and may be, for example, 30ms, 50ms, 70ms, 100ms, 130ms, 150ms, 170ms, etc.

At label 11, UE 402 (as an example, LTE component 412) may receive a second response message from eNB 404. The second response message may be sent in response to the first measurement report and comprising an indication that the 5G NR cell has been released. For example, the second response message may comprise a RRCconnectionReconfiguration message with an indication to remove 5G SCG cell and/or remove related DRB (data radio bearer) . UE 402 (as an example, LTE component 412) may determine whether the second response message is received before expiration of the first timer. If the second response message is received before expiration of the first timer based on the determination, UE 402 (as an example, LTE component 412) may stop the first timer.

At label 12, if the second response message is not received before the expiration of the first timer based on the determination, UE 402 (as an example, LTE component 412) may send a failure indication message indicating failure of the 5G NR cell to eNB 404. The failure indication message may comprise, e.g., a UL_DCCH (uplink dedicated control channel) Extension c2 SCGFailureInformationNR-r15 message with failureType-r15 = t310-Expiry, or a similar message. If the measurement event is not configured based on the determination of label 9, UE 402 (as an example, LTE component 412) may send a failure indication message indicating failure of the 5G NR cell to eNB 404. The failure indication message may comprise, for example, a UL_DCCH (uplink dedicated control channel) Extension c2 SCGFailureInformationNR-r15 message with failureType-r15 = t310-Expiry, or a similar message.

At label 13, UE 402 may receive a second response message from the eNB 404, the second response message sent in response to the failure indication message (label 12) and comprising an indication that the 5G NR cell has been released. For example, the second response message may comprise a RRCconnectionReconfiguration message with an indication to remove/release 5G SCG cell and/or remove/release related DRB (data radio bearer) .

At label 14, UE 402 may ignore a measurement request associated with 5G NR RAT received before successfully re-initiating 5G NR component 414 of UE 402. The measurement request may comprise an L2NR B1 measurement request.

At label 15, UE 402 may maintain a visual indicator associated with 5G NR RAT on a display of the UE 402, as, for example, just 5G NR DRB has been removed. UE 402 (as an example, LTE component 412) may exchange the information with eNB 404/EPC 408/AP 410, for example, in response to the indication that the cell of the second type of RAT has been released/removed. The information may comprise the information that was originally to be or being sent/received via 5G NR component 414. For example, by shifting sending/receiving of information from 5G NR component 414 to LTE component 412, user may still use data service as before 5G NR component 414 malfunctioned.

At label 16, in response to successfully re-initiating 5G NR component 414, UE 402 (as an example, 5G NR component 414) may send a second indication to LTE component 412, the second indication indicating that the event is over. The indication may comprise a user-defined signal/message/parameter/flag, for example, 5g_crash_ind_to_4G false. A successful re-initiation of a component may comprise, for example, the component passing a diagnostic test, the component being responsive to communications, the component being in an initial/startup state, the component providing an indication that it is working/functional, etc.

At label 17, UE 402 (as an example, LTE component 412) may send a second measurement report of a 5G NR cell to eNB 404. The second measurement report may indicate a signaling environment for 5G NR RAT that is above a second threshold. For example, the measurement report may indicate or be associated with a B1 event.

At label 18, UE 402 may receive a third response message from eNB 404, the third response message comprising an indication of addition of the 5G NR cell associated with the second measurement report, and/or addition of related DRB.

At label 19, UE 402 may exchange the information with a 5G NR BS of the cell associated with the second measurement report. The information may comprise the information that was originally to be or being sent/received via 5G NR component 414. The 5G NR BS may be the same as gNB 406 or may be a different 5G NR BS. Usage of dual connectivity (e.g., EN-DC) , such as that associated with label 6, is resumed.

The example of FIG. 6 may not involve much communication with the core network (e.g., EPC 408) , and may result in less signaling overhead, which may lead to a shorter completion time (for example, around 10-20ms for certain configurations) .

FIG. 7 illustrates an example flow diagram, in accordance with certain aspects of the present disclosure. The UE, LTE eNB, 5G NR gNB, and EPC of FIG. 7 may comprise, respectively, UE 402, eNB 404, gNB 406, and EPC 408 of FIG. 4. In the example of FIG. 7, labels 1 to 7 may be the same as or similar to corresponding labels of FIG. 5.

In the example of FIG. 7, UE 402 may take action in response to losing communication with gNB 406.

Label 8 of FIG. 7 may be the same as or similar to label 8 of FIG. 6.

At label 9, UE 402 (as an example, LTE component 412) may send a first update message comprising an indication of support for a second connection mode to EPC 408, the second connection mode comprising a connection to LTE RAT only. The first update message may comprise a tracking area update (TAU) . The TAU may comprise a parameter indicating to EPC 408 to release/remove 5G NR cell and/or 5G DRB, for example, by RRC reconfiguration. The parameter may comprise DCNR (dual connectivity NR) = 0, indicating support for a connection to LTE RAT only.

At label 10, UE 402 may receive a second response message from eNB 404, the second response message sent in response to the first update message and comprising a second indication that the 5G NR SCG cell has been released/removed.

At label 11, UE 402 may maintain a visual indicator associated with 5G NR RAT on a display of the UE 402, as, for example, just 5G NR DRB has been removed. UE 402 (as an example, LTE component 412) may exchange the information with eNB 404/EPC 408/AP 410, for example, in response to the indication that the 5G NR cell has been released/removed. The information may comprise the information that was originally to be or being sent/received via 5G NR component 414. For example, by shifting sending/receiving of information from 5G NR component 414 to LTE component 412, user may still use data service as before 5G NR component 414 malfunctioned.

At label 12, in response to successfully re-initiating 5G NR component 414 and/or in response to the indication that the 5G NR cell has been released/removed, UE 402 (as an example, 5G NR component 414) may send a second indication to LTE component 412, the second indication indicating that the event is over. The indication may comprise a user-defined signal/message/parameter/flag, for example, 5g_crash_ind_to_4G false.

At label 13, UE 402 (as an example, LTE component 412) may send a second update message comprising an indication of support for the first connection mode to EPC 408. The second update message may comprise a tracking area update (TAU) . The TAU may comprise a parameter indicating to EPC 408 support for both LTE and 5G NR. The parameter, for example, may comprise DCNR (dual connectivity NR) = 1.

At label 14, in response to the second update message, EPC 408 or eNB 404 may add a 5G SCG cell, for example, by RRC reconfiguration. UE 402 may exchange the information with a 5G NR BS associated with the added cell. The information may comprise the information that was originally to be or being sent/received via 5G NR component 414. The 5G NR BS may be the same as gNB 406 or may be a different 5G NR BS. Usage of dual connectivity (e.g., EN-DC) , such as that associated with label 6, is resumed.

The example of FIG. 7 involves communication with the core network (e.g., EPC 408) , thus it may provide more clear indication to the core network that UE DCNR capability is lost or removed, which may allow the core network to have more clear knowledge about what is going on at the UE. Due to the communication with the core network, it may result in more signaling overhead, which may lead to a longer completion time (for example, around 100-200ms for certain configurations) .

FIG. 8 illustrates example operations 800 for wireless communications, e.g., by a UE, in accordance with certain aspects of the present disclosure. The UE may comprise UE 402 of FIG. 4, for example, and may support a first type of RAT and a second type of RAT. At 802, the UE may send an attach request message comprising an indication of support for a first connection mode to a network entity, the first connection mode comprising connections to both the first type of RAT and the second type of RAT.

At 804, the UE may receive a first response message from a first base station (BS) of the first type of RAT, the first response message sent in response to the attach request message and comprising an indication of addition of a cell of the second type of RAT.

At 806, the UE may connect to a second BS of the cell of the second type of RAT, in response to receiving the response message.

At 808, the UE may send a message indicating connection complete to the first BS.

At 810, the UE may exchange information with the second BS, in response to sending the message indicating connection complete.

At 812, the UE may lose communication with the second BS due to an event related to a component of the UE associated with the second type of RAT, while exchanging the information with the second BS.

At 814, the UE may take action in response to losing the communication with the second BS. In accordance with certain aspects of the present disclosure, the actions may reduce impact of malfunction in the UE which may be a cause of the event.

In accordance with certain aspects of the present disclosure, taking the action may comprise: sending a first indication of the event to a component of the UE associated with the first type of RAT; and re-initiating the component of the UE associated with the second type of RAT.

In accordance with certain aspects of the present disclosure, taking the action may further comprise: determining whether a measurement event is configured for the second type of RAT; if the measurement event is configured based on the determination: sending a first measurement report for the cell of the second type of RAT to the first BS; receiving a second response message from the first BS, the second response message sent in response to the first measurement report and comprising an indication that the cell of the second type of RAT has been released; if the measurement event is not configured based on the determination: sending a failure indication message indicating a failure of the cell of the second type of RAT to the first BS; receiving a second response message from the first BS, the second response message sent in response to the failure indication message and comprising an indication that the cell of the second type of RAT has been released; and in response to the indication that the cell of the second type of RAT has been released, exchanging the information with the first BS using the component of the UE associated with the first type of RAT.

In accordance with certain aspects of the present disclosure, taking the action may further comprise: starting a first timer in response to sending the first measurement report; and determining whether the second response message is received before expiration of the first timer; if the second response message is received before the expiration of the first timer based on the determination, stop the first timer; and if the second response message is not received before the expiration of the first timer based on the determination, sending a failure indication message indicating failure of the cell of the second type of RAT to the first BS.

In accordance with certain aspects of the present disclosure, taking the action may further comprise: in response to successfully re-initiating the component of the UE associated with the second type of RAT: sending a second indication to the component of the UE associated with the first type of RAT, the second indication indicating that the event is over; sending a second measurement report of a cell of the second type of RAT to the first BS; receiving a third response message from the first BS, the third response message comprising an indication of addition of the cell associated with the second measurement report, of the second type of RAT; and exchanging the information with a third BS of the cell associated with the second measurement report, of the second type of RAT.

In accordance with certain aspects of the present disclosure, the second BS and the third BS may be the same.

In accordance with certain aspects of the present disclosure, taking the action may further comprise ignoring a measurement request associated with the second type of RAT received before successfully re-initiating the component of the UE associated with the second type of RAT.

In accordance with certain aspects of the present disclosure, taking the action may further comprise: sending a first update message comprising an indication of support for a second connection mode to the network entity, the second connection mode comprising a connection to the first type of RAT only; receiving a second response message from the first BS, the second response message sent in response to the first update message and comprising a second indication that the cell of the second type of RAT has been released; and in response to the second indication that the cell of the second type of RAT has been released, exchanging the information with the first BS using the component of the UE associated with the first type of RAT.

In accordance with certain aspects of the present disclosure, taking the action may further comprise: in response to the second indication that the cell of the second type of RAT has been released and in response to successfully re-initiating the component of the UE associated with the second type of RAT: sending a third indication to the component of the UE associated with the first type of RAT, the third indication indicating that the event is over; sending a second update message comprising an indication of support for the first connection mode to the network entity; and exchanging the information with a third BS of the second type of RAT, the third BS associated with a cell of the second type of RAT that is added in response to the second update message.

In accordance with certain aspects of the present disclosure, the first update message may comprise a tracking area update (TAU) .

In accordance with certain aspects of the present disclosure, the second update message may comprise a tracking area update (TAU) .

In accordance with certain aspects of the present disclosure, the first type of RAT may comprise a Long Term Evolution (LTE) RAT, and the second type of RAT may comprise a 5G New Radio (NR) RAT.

In accordance with certain aspects of the present disclosure, the network entity may comprise a core network entity.

In accordance with certain aspects of the present disclosure, the first response message may comprise a radio resource control (RRC) reconfiguration message.

In accordance with certain aspects of the present disclosure, connecting to the second BS may comprise performing random access with the second BS.

In accordance with certain aspects of the present disclosure, exchanging the information may be based at least in part on an operation mode.

In accordance with certain aspects of the present disclosure, the operation mode may comprise at least one of options: 3, 3x, or 3A.

In accordance with certain aspects of the present disclosure, the event may comprise a malfunction of the component of the UE associated with the second type of RAT.

In accordance with certain aspects of the present disclosure, the re-initiating may comprise at least one of: reconfiguring, rebooting, restarting, or resetting.

In accordance with certain aspects of the present disclosure, the first measurement report may indicate a signaling environment for the second type of RAT that is below a first threshold.

In accordance with certain aspects of the present disclosure, the second measurement report may indicate a signaling environment for the second type of RAT that is above a second threshold.

In accordance with certain aspects of the present disclosure, taking the action may further comprise maintaining a visual indicator associated with the second type of RAT on a display of the UE.

While certain examples of the present disclosure refers to LTE and 5G NR, according an aspect of the present disclosure, the techniques of this disclosure may be applicable to other types of RATs, including future RATs.

UE components for performing operations 800 may include antenna 352, receiver/transmitter 354, receiver processor 356, channel estimator 358, transmit processor 368, and/or controller/processor 359 of FIG. 3.

It is understood that the specific order or hierarchy of blocks or flows in the processes /flowcharts disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks or flows in the processes /flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims may present elements of the various blocks or flows in a sample order, and are not meant to be limited to the specific order or hierarchy presented, unless otherwise indicated.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Moreover, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or. ” That is, unless specified otherwise, or clear from the context, the phrase, for example, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, for example the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. As used herein, reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” For example, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from the context to be directed to a singular form. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. ) . As used herein, the term “and/or, ” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

In some cases, rather than actually communicating a frame, a device may have an interface to communicate a frame for transmission or reception. For example, a processor may output a frame, via a bus interface, to an RF front end for transmission. Similarly, rather than actually receiving a frame, a device may have an interface to obtain a frame received from another device. For example, a processor may obtain (or receive) a frame, via a bus interface, from an RF front end for transmission.

The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps, techniques, mechanisms, methodologies, and/or actions may be interchanged with one another, and/or work together with each other, without departing from the scope of the claims. In other words, unless a specific order or combination of steps, techniques, mechanisms, methodologies, and/or actions is specified, the order, combination, and/or use of specific steps, techniques, mechanisms, methodologies, and/or actions may be modified without departing from the scope of the claims.

The various operations, blocks, flows, processes, and/or activities described herein may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component (s) and/or module (s) , including, but not limited to a circuit, an application specific integrated circuit (ASIC) , or processor. Generally, where there are operations, flows, processes, and/or activities illustrated in Figures, they may be performed by any suitable corresponding counterpart means-plus-function components. The aforementioned means may include one or more of the aforementioned components of the UE 350 and/or BS 310 configured to perform the functions recited by the means. A processing system for a UE may include TX Processor 368, RX Processor 356, and the controller/processor 359. As such, in one configuration, the means may include TX Processor 368, RX Processor 356, and/or controller/processor 359 configured to perform the functions recited by the means. TX Processor 368, RX Processor 356, and/or the controller/processor 359 may be part of a modem/modem processor of the UE, or part of an application processor of the UE, or part of both the modem/modem processor and the application processor of the UE. The modem/modem processor and the application processor may be separate hardware components, or may be integrated together on the same hardware component as, e.g., a system on a chip (SoC) .

For example, means for connecting, means for exchanging, means for losing, means for taking, means for re-initiating, means for maintaining, means for signaling, means for attempting, means for stopping, means for identifying, means for comparing, means for determining, means for scanning, means for adjusting, means for entering, means for supporting, means for performing, means for initiating, means for completing, means for communicating, means for scrambling, means for assigning, means for occupying, means for defining, means for targeting, means for configuring, means for processing, means for indicating, means for measuring, means for estimating, means for enabling, means for selecting, means for transmitting, means for receiving, means for sending, means for mapping, means for synchronizing, means for prioritizing, means for allocating, means for rejecting, means for restricting, means for increasing, and/or means for decreasing may include one or more processors/controllers, transmitters, receivers, antennas, and/or other modules, components, or elements of, for example,

user equipment

104, 350, base station 102/180, 310, and/or another network entity. The words “module, ” “mechanism, ” “component, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or combinations thereof.

As used herein, the terms “identify” or “determine” , and their other forms such as “identifying” , “identified” , “identification” , “determining” , “determination” , etc., encompass a wide variety of actions. For example, “identifying” or “determining” may include measuring, calculating, computing, processing, deriving, investigating, identifying, determining, detecting, looking up (e.g., looking up in a table, a database or another data structure) , ascertaining, storing, characterizing, capturing, and the like. Also, “identifying” or “determining” may include receiving (e.g., receiving information) , accessing (e.g., accessing data in a memory) and the like. Also, “identifying” or “determining” may include resolving, selecting, choosing, establishing and the like. The aforementioned

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as hardware, software, or combinations thereof. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. One or more aforementioned devices or processors may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination thereof. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, phase change memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions described may be implemented in hardware, software, or combinations thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD/DVD or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk and

disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communications by a user equipment (UE) that supports a first type of radio access technology (RAT) and a second type of RAT, comprising:

sending an attach request message comprising an indication of support for a first connection mode to a network entity, the first connection mode comprising connections to both the first type of RAT and the second type of RAT;

receiving a first response message from a first base station (BS) of the first type of RAT, the first response message sent in response to the attach request message and comprising an indication of addition of a cell of the second type of RAT;

connecting to a second BS of the cell of the second type of RAT, in response to receiving the first response message;

sending a message indicating connection complete to the first BS, in response to connecting to the second BS;

exchanging information with the second BS, in response to sending the message indicating connection complete;

losing communication with the second BS due to an event related to a component of the UE associated with the second type of RAT, while exchanging the information with the second BS; and

taking action in response to losing the communication with the second BS.
The method of claim 1, wherein taking the action comprises:

sending a first indication of the event to a component of the UE associated with the first type of RAT; and

re-initiating the component of the UE associated with the second type of RAT.
The method of claim 2, wherein taking the action further comprises:

determining whether a measurement event is configured for the second type of RAT;

if the measurement event is configured based on the determination:

sending a first measurement report for the cell of the second type of RAT to the first BS;

receiving a second response message from the first BS, the second response message sent in response to the first measurement report and comprising an indication that the cell of the second type of RAT has been released;

if the measurement event is not configured based on the determination:

sending a failure indication message indicating a failure of the cell of the second type of RAT to the first BS;

receiving a second response message from the first BS, the second response message sent in response to the failure indication message and comprising an indication that the cell of the second type of RAT has been released; and

in response to the indication that the cell of the second type of RAT has been released, exchanging the information with the first BS using the component of the UE associated with the first type of RAT.
The method of claim 3, wherein taking the action further comprises:

starting a first timer in response to sending the first measurement report; and

determining whether the second response message is received before expiration of the first timer;

if the second response message is received before the expiration of the first timer based on the determination, stop the first timer; and

if the second response message is not received before the expiration of the first timer based on the determination, sending a failure indication message indicating failure of the cell of the second type of RAT to the first BS.
The method of claim 4, wherein taking the action further comprises:

in response to successfully re-initiating the component of the UE associated with the second type of RAT:

sending a second indication to the component of the UE associated with the first type of RAT, the second indication indicating that the event is over;

sending a second measurement report of a cell of the second type of RAT to the first BS;

receiving a third response message from the first BS, the third response message comprising an indication of addition of the cell associated with the second measurement report, of the second type of RAT; and

exchanging the information with a third BS of the cell associated with the second measurement report, of the second type of RAT.
The method of claim 5, wherein the second BS and the third BS are the same.
The method of claim 2, wherein taking the action further comprises ignoring a measurement request associated with the second type of RAT received before successfully re-initiating the component of the UE associated with the second type of RAT.
The method of claim 2, wherein taking the action further comprises:

sending a first update message comprising an indication of support for a second connection mode to the network entity, the second connection mode comprising a connection to the first type of RAT only;

receiving a second response message from the first BS, the second response message sent in response to the first update message and comprising a second indication that the cell of the second type of RAT has been released; and

in response to the second indication that the cell of the second type of RAT has been released, exchanging the information with the first BS using the component of the UE associated with the first type of RAT.
The method of claim 8, wherein taking the action further comprises:

in response to the second indication that the cell of the second type of RAT has been released and in response to successfully re-initiating the component of the UE associated with the second type of RAT:

sending a third indication to the component of the UE associated with the first type of RAT, the third indication indicating that the event is over;

sending a second update message comprising an indication of support for the first connection mode to the network entity; and

exchanging the information with a third BS of the second type of RAT, the third BS associated with a cell of the second type of RAT that is added in response to the second update message.
The method of claim 8, wherein the first update message comprises a tracking area update (TAU) .
The method of claim 9, wherein the second update message comprises a tracking area update (TAU) .
The method of claim 9, wherein the second BS and the third BS are the same.
The method of claim 1, wherein the first type of RAT comprises a Long Term Evolution (LTE) RAT, and the second type of RAT comprises a 5G New Radio (NR) RAT.
The method of claim 1, wherein the network entity comprises a core network entity.
The method of claim 1, wherein the first response message comprises a radio resource control (RRC) reconfiguration message.
The method of claim 1, wherein connecting to the second BS comprises performing random access with the second BS.
The method of claim 1, wherein exchanging the information is based at least in part on an operation mode.
The method of claim 17, wherein the operation mode comprises at least one of options: 3, 3x, or 3A.
The method of claim 1, wherein the event comprises a malfunction of the component of the UE associated with the second type of RAT.
The method of claim 2, wherein the re-initiating comprises at least one of: reconfiguring, rebooting, restarting, or resetting.
The method of claim 3, wherein the first measurement report indicates a signaling environment for the second type of RAT that is below a first threshold.
The method of claim 5, wherein the second measurement report indicates a signaling environment for the second type of RAT that is above a second threshold.
The method of claim 2, wherein the taking the action further comprises maintaining a visual indicator associated with the second type of RAT on a display of the UE.
A method, device, apparatus, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, or processing system as described herein with reference to and as illustrated by the accompanying figures and specification.