Enhancing mobility robustness optimization using fallback indication of inter-system handover reporting

Abstract

A user equipment (UE) disconnects from a next generation radio access network (NG-RAN) base station (BS) and receives a fallback indication from the NG-RAN BS. The UE then attempts to connect to an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN) BS. The UE determines that communication with the E-UTRAN BS is not established and identifies a backup BS. Upon establishing communication with the backup BS, the UE generates a report and sends the report to the backup BS, the report including the fallback indication and information about the failed connection attempt with the E-UTRAN BS. The report is then delivered to the NG-RAN BS to optimize the future fallback procedure.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Patent Application No. 18 / 351,851, filed on July 13, 2023, and U.S. Provisional Application No. 63 / 370,727, filed on August 8, 2022, the disclosures of which are incorporated herein by reference in their entirety as if fully set forth below and for all applicable purposes. Technical Field

[0003] The present disclosure relates to wireless communication systems and methods, and more particularly to devices, systems, and methods for enhancing mobility robustness optimization (MRO) using a fallback indication of an inter-system handover report. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, and the like. Due to the mobile nature of various wireless communication devices, such as user equipment (UE), and the allocation of different functions to different types of wireless communication devices to provide mobile communications, wireless communication devices must transfer wireless connections from one device to another. For example, a UE may communicate wirelessly with a base station (BS). A handover process or a redirection process may be implemented to disconnect the UE from the BS and connect it to another different BS, which is referred to as a fallback. The fallback may be performed in response to different reasons, resulting in different types of fallbacks, such as voice fallback, emergency fallback, fallback for load balancing, fallback for solving coverage problems, or other types. Summary of the invention

[0005] The following summarizes some aspects of the present disclosure to provide a basic understanding of the technology discussed. This summary is not an exhaustive overview of all the expected features of the present disclosure, and is neither intended to identify the key or important elements of all aspects of the present disclosure, nor to delineate the scope of any or all aspects of the present disclosure. The sole purpose of this summary is to present some concepts of one or more aspects of the present disclosure in a summarized form as a prelude to more specific embodiments presented later.

[0006] According to one aspect of the present disclosure, a method of wireless communication includes receiving, by a first wireless communication device, a first signal from a first next generation radio access network (NG-RAN) base station, the first signal including a fallback indication. The method also includes, in response to receiving the first signal, sending, by the first wireless communication device, a second signal to a first evolved universal mobile telecommunications system terrestrial radio access network (E-UTRAN) base station, the second signal including a connection request. The method also includes sending, by the first wireless communication device, a third signal to a second wireless communication device, the third signal including a report in response to a connection failure with the first E-UTRAN base station.

[0007] According to another aspect of the present disclosure, a method of wireless communication includes receiving, by a first wireless communication device, a first signal from a user equipment (UE), the first signal including a connection request. The method also includes sending, by the first wireless communication device, a second signal to the UE, the second signal including an information request. The method also includes receiving, by the first wireless communication device, a third signal from the UE, the third signal including a report generated in response to a failure to establish a connection between the UE and a second wireless communication device, the report including a fallback indication.

[0008] According to another aspect of the present disclosure, a wireless communication device includes: a transceiver; and a processor coupled to the transceiver, wherein the wireless communication device is configured to receive a first signal from a first next generation radio access network (NG-RAN) base station, the first signal including a fallback indication. The wireless communication device is also configured to, in response to receiving the first signal, send a second signal to a first evolved universal mobile telecommunications system terrestrial radio access network (E-UTRAN) base station, the second signal including a connection request. The wireless communication device is also configured to send a third signal to a second wireless communication device, the third signal including a report in response to a connection failure with the first E-UTRAN base station.

[0009] According to another aspect of the present disclosure, a wireless communication device includes: a transceiver; and a processor coupled to the transceiver, wherein the wireless communication device is configured to: receive a first signal from a user equipment (UE), the first signal including a connection request. The wireless communication device is also configured to send a second signal to the UE, the second signal including an information request. The wireless communication device is also configured to receive a third signal from the UE, the third signal including a report generated in response to a failure to establish a connection between the UE and a second wireless communication device, the report including a fallback indication.

[0010] After reading the following description of specific exemplary aspects in conjunction with the accompanying drawings, other aspects, features, and embodiments will become apparent to those of ordinary skill in the art. Although each feature may be discussed below with respect to certain aspects and drawings, all aspects may include one or more of the advantageous features discussed herein. In other words, although one or more aspects may be discussed as having certain advantageous features, one or more of such features may also be used according to the various aspects discussed herein. In a similar manner, although the exemplary aspects may be discussed below as aspects of devices, systems, or methods, it should be understood that such exemplary aspects may be implemented in various devices, systems, and methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A wireless communication network according to some aspects of the present disclosure is illustrated.

[0012] Figure 2 Communication scenarios involving a UE, one or more BSs, and a control plane according to some aspects of the present disclosure are illustrated.

[0013] Figure 3 is a block diagram of an exemplary UE according to some aspects of the present disclosure.

[0014] Figure 4 is a block diagram of an exemplary BS according to some aspects of the present disclosure.

[0015] Figure 5 is a graphical representation of a report in accordance with aspects of the present disclosure.

[0016] Figure 6 is a signaling diagram of communications between a UE, an NG-RAN BS, an E-UTRAN BS, and control plane elements according to various aspects of the present disclosure.

[0017] Figure 7 is a signaling diagram of communications between a UE, a NG-RAN BS, an E-UTRAN BS, and a NG-RAN BS according to various aspects of the present disclosure.

[0018] Figure 8 is a signaling diagram of communications between a UE, an NG-RAN BS, and an E-UTRAN BS according to various aspects of the present disclosure.

[0019] Fig. 9 is a flow chart of a method of wireless communication according to some aspects of the present disclosure.

[0020] Fig.10 is a flow chart of a method of wireless communication according to some aspects of the present disclosure.

[0021] Fig.11is a diagram illustrating an example decomposed BS architecture according to some aspects of the present disclosure.

[0022] Fig.12 A diagram illustrating a system including devices supporting RU sharing technology in wireless communications according to some aspects of the present disclosure is illustrated. DETAILED DESCRIPTION

[0023] The specific embodiments described below in conjunction with the accompanying drawings are intended as descriptions of various configurations and are not intended to represent the only configurations with which the concepts described herein can be practiced. In order to provide a comprehensive understanding of the various concepts, the specific embodiments include specific details. However, it is apparent to those skilled in the art that these concepts can be practiced without these specific details. In some instances, in order to avoid obscuring such concepts, well-known structures and components are shown in block diagram form.

[0024] The present disclosure as a whole relates to wireless communication systems, which are also referred to as wireless communication networks. In various embodiments, each technology and device can be used for wireless communication networks, such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA (SC-FDMA) networks, LTE networks, global mobile communication systems (GSM) networks, fifth generation (5G) or new radio (NR) networks, and other communication networks. As described herein, the terms "network" and "system" can be used interchangeably.

[0025] OFDMA network can implement radio technology such as Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM, etc. UTRA, E-UTRA and GSM are part of Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a version of UMTS using E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided by an organization named "3rd Generation Partnership Project" (3GPP), and cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). These radio technologies and standards are known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between telecommunication association groups with the goal of defining globally applicable third generation (3G) mobile phone specifications. 3GPP Long Term Evolution (LTE) is a 3GPP plan to improve UMTS mobile phone standards. 3GPP may define specifications for next generation mobile networks, mobile systems, and mobile devices. The present disclosure relates to the evolution from LTE, 4G, 5G, NR and beyond wireless technologies, where access to the wireless spectrum is shared between networks using a range of new and different radio access technologies or radio air interfaces.

[0026] Specifically, 5G networks consider various deployments, various spectrums, and various services and devices that can be implemented using a unified air interface based on OFDM. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to scale to (1) ultra-high density (e.g., about 1M nodes / km) 2 (1) provide coverage for the massive Internet of Things (IoT) with ultra-low complexity (e.g., on the order of tens of bits / second), ultra-low energy (e.g., on the order of 10+ years battery life), and deep coverage with the ability to reach challenging locations; (2) provide coverage including mission-critical control with strong security to protect sensitive personal, financial, or classified information, ultra-high reliability (e.g., on the order of 99.9999% reliability), ultra-low latency (e.g., on the order of 1 millisecond), and for users with extensive mobility or lack of mobility; and (3) provide coverage with enhanced mobile broadband (including extremely high capacity (e.g., on the order of 10Tbps / km 2 ), extremely high data rates (e.g., multi-Gbps rates, 100+Mbps user experience rates), and deep awareness coverage with advanced discovery and optimization.

[0027] The 5G NR communication system can be implemented as an optimized OFDM-based waveform with a scalable parameter set and a transmission time interval (TTI). Additional features may also include a common, flexible framework to efficiently multiplex services and features using a dynamic low-latency time division duplex (TDD) / frequency division duplex (FDD) design; and advanced wireless technologies such as massive multiple-input multiple-output (MIMO), robust millimeter wave (mmWave) transmission, advanced channel decoding, and device-centric mobility. The scalability of the parameter set in 5G NR and the scaling of the subcarrier spacing can efficiently solve various services across different spectrums and different deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD / TDD implementations, the subcarrier spacing may appear at 15kHz on bandwidths (BW) such as 5MHz, 10MHz, and 20MHz. For other various outdoor and small cell coverage deployments of TDD greater than 3GHz, the subcarrier spacing may appear at 30kHz on 80MHz / 100MHz BW. For various other indoor broadband implementations, using TDD on the unlicensed portion of the 5 GHz band, subcarrier spacing may occur at 60 kHz over 160 MHz BW. Finally, for various deployments transmitting with the mmWave component at 28 GHz TDD, subcarrier spacing may occur at 120 kHz over 500 MHz BW.

[0028] 5G NR's scalable parameter sets facilitate scalable TTIs for different latency and quality of service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. Efficient multiplexing of long and short TTIs allows transmission to start on symbol boundaries. 5G NR also envisions a self-contained integrated subframe design with UL / downlink scheduling information, data, and acknowledgment in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive UL / downlink (which can be flexibly configured on a per-cell basis to dynamically switch between UL and downlink to meet current business needs).

[0029] The various other aspects and features of the present disclosure are further described below. It should be apparent that the teachings herein can be embodied in various forms, and any specific structure, function, or both disclosed herein are merely representative and not restrictive. Based on the teachings herein, it should be understood by those of ordinary skill in the art that the aspects disclosed herein can be implemented independently of any other aspects, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement a device or practice a method. In addition, such a device can be implemented or such a method can be practiced using other structures, functionality, or structures and functionality other than or different from one or more of the aspects set forth herein. For example, the method can be implemented as a part of a system, device, device, and / or as an instruction stored on a computer-readable medium for execution on a processor or computer. In addition, one aspect can include at least one element of a claim.

[0030] 5G NR provides increased reliability and ubiquity of wireless data transmission. With the rollout of 5G NR, the existing infrastructure configured for 3G, 4G and LTE continues to exist and operate. In some instances, 5G NR wireless communication devices such as base stations (BS) can work in conjunction with wireless communication devices or other components configured for 3G, 4G and / or LTE. In some aspects, various functions of wireless communication can be assigned to 5G infrastructure, while other functions are assigned to LTE infrastructure. Therefore, according to its physical location and / or the specified function or process to be performed, the user equipment (UE) must be able to communicate with both 5G infrastructure equipment and LTE infrastructure equipment, and quickly and efficiently switch communication between these devices. In some aspects, for example, when the communication between UE and LTE BS is transferred to the communication between UE and 5G BS, a report related to the transfer of communication can be generated and provided to the original LTE BS or the new 5G BS to improve similar communication transfers in the future.

[0031] In order to better promote the coverage expansion of wireless data transmission, various aspects of the present disclosure provide systems, devices and methods for providing feedback information to the BS involved in the fallback process, in which the communication to and from the 5G BS and the UE is transferred to the LTE BS. Specifically, the 5G BS and the UE may be disconnected. As part of the disconnection, the 5G BS may provide the UE with a fallback indication related to which type of fallback has occurred. The UE may store the information and then search for and identify the LTE BS. Then, the UE transmits a connection request to the LTE BS. In the case where a connection with the LTE BS is not established, the UE may store information related to the failed connection attempt. The UE may then identify an alternative BS (such as an LTE BS or a 5G BS) and transmit a connection request to the alternative BS. After establishing a connection with the alternative BS, the alternative BS may request various reports from the UE. The UE may generate a report based on the stored information related to the disconnection from the 5G BS and the failed connection. The information may include a fallback indication. The standby BS may then send any of the information, including the fallback indication, from the UE to the 5G BS that initially communicated with the UE. The information may be sent directly or via a component of the core network. In some aspects, the 5G BS that initially communicated with the UE may perform various optimizations based on information received from an alternative BS. Such optimizations may include directing UEs involved in future fallbacks to different LTE BSs, specifying different types of BSs, or other optimizations. In this regard, aspects of the present disclosure advantageously, quickly, and efficiently provide feedback information to BSs involved in various types of fallback processes, thereby achieving improved communication quality.

[0032] In some cases, a UE that has been disconnected from a BS may identify a new BS and transmit a connection request to the new BS. However, due to various reasons, the connection request may fail and wireless communication may not be established between the UE and the new BS. The UE may then identify an alternative BS and transmit a connection request to the alternative BS. During the fallback process, when reconnection to the new BS fails, it may be desirable to record information related to the connection failure and provide the information to the BS to which the UE was originally connected to improve future fallback processes. However, in the case where the BS originally connected is a 5G NR BS and the new BS selected by the UE for reconnection is an LTE BS, the current infrastructure does not support the delivery of this information to the BS. Therefore, an improved method of the fallback process is needed, which allows failed connection information to be sent to the BS involved in the case of LTE fallback from 5G NR.

[0033] Figure 1A wireless communication network 100 according to some aspects of the present disclosure is illustrated. The network 100 may be a 5G network. The network 100 includes several base stations (BSs) 105 (respectively labeled 105a, 105b, 105c, 105d, 105e, and 105f) and other network entities. The BS 105 may be a station that communicates with the UE 115, and may also be referred to as an evolved Node B (eNB), a next generation eNB (gNB), an access point, and the like. Each BS 105 may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to the particular geographic coverage area of ​​the BS 105 and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0034] BS105 may provide communication coverage for macro cells or small cells (such as pico cells or femto cells) and / or other types of cells. Macro cells generally cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with a network provider. Small cells (such as pico cells) will generally cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions with a network provider. Small cells (such as femto cells) will generally also cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs associated with the femto cells (e.g., UEs in a closed subscriber group (CSG), UEs of users in a home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS, or a home BS. In Figure 1 In the example shown, BS105d and 105e may be conventional macro BSs, while BS105a-105c may be macro BSs with one of three-dimensional (3D), full-dimensional (FD) or massive MIMO capabilities. BS 105a-105c may utilize its higher-dimensional MIMO capabilities to employ 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. BS105f may be a small cell BS, which may be a home node or a portable access point. BS105 may support one or more (e.g., two, three, four, etc.) cells.

[0035] Network 100 may support synchronous operation or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time.

[0036] UE 115 is dispersed throughout the wireless network 100, and each UE 115 can be stationary or mobile. UE 115 may also be referred to as a terminal, a mobile station, a subscriber unit, a station, etc. UE 115 may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, etc. In one aspect, UE 115 may be a device including a universal integrated circuit card (UICC). On the other hand, UE may be a device that does not include a UICC. In some aspects, UE 115 that does not include a UICC may also be referred to as an IoT device or an Internet of Everything (IoE) device. UE 115a-115d is an example of a mobile smart phone type device that accesses the network 100. UE 115 may also be a machine that is specifically configured for connected communications (including machine type communications (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT), etc.). UE 115e-115h are examples of various machines configured for communication to access network 100. UE 115i to 115k are examples of vehicles equipped with wireless communication devices configured for communication to access network 100. UE 115 may be able to communicate with any type of BS, whether macro BS, small cell, etc. Figure 1 , a lightning symbol (e.g., a communication link) indicates wireless transmission between UE 115 and a serving BS 105 (which is a BS designated to provide service to UE 115 on a downlink (DL) and / or uplink (UL), desired transmission between BSs 105, backhaul transmission between BSs, or sidelink transmission between UE 115.

[0037] In operation, BSs 105a-105c use 3D beamforming and cooperative spatial techniques such as coordinated multipoint (CoMP) or multiple connections to serve UEs 115a and 115b. Macro BS 105d may perform backhaul communications with BSs 105a-105c and small cell BS 105f. Macro BS 105d may also transmit multicast services that UEs 115c and 115d subscribe to and receive. Such multicast services may include mobile TV or streaming video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

[0038] The BSs 105 may also communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs 105 (e.g., which may be examples of gNBs or access node controllers (ANCs)) may interface with the core network via a backhaul link (e.g., NG-C, NG-U, etc.) and may perform radio configuration and scheduling for communications with the UE 115. In various examples, the BSs 105 may communicate with each other directly or indirectly (e.g., via a core network) via a backhaul link (e.g., X1, X2, etc.), which may be a wired communication link or a wireless communication link.

[0039] The network 100 may also support mission-critical communications using ultra-reliable and redundant links for mission-critical devices such as UE 115e, which may be a drone. The redundant communication links with UE 115e may include links from macro BSs 105d and 105e, and links from small cell BS 105f. Other machine-type devices, such as UE 115f (e.g., a thermometer), UE 115g (e.g., a smart meter), and UE 115h (e.g., a wearable device), may communicate directly with BSs such as small cell BS 105f and macro BS 105e through the network 100, or communicate through the network in a multi-step configuration by communicating with another user device such as UE 115f that communicates temperature measurement information to a smart meter (UE 115g), which then reports to the network through the small cell BS 105f, which relays its information to the network. The network 100 may also provide additional network efficiency through dynamic low latency TDD / FDD communications, such as V2V, V2X, C-V2X communications (e.g., sidelink communications) between UE 115i, 115j, or 115k and other UEs 115, and / or vehicle-to-infrastructure (V2I) communications between UE 115i, 115j, or 115k and BS 105.

[0040] In some implementations, the network 100 utilizes an OFDM-based waveform for communication. An OFDM-based system may divide the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, frequency bins, etc. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may depend on the system BW. The system BW may also be divided into subbands. In other instances, the subcarrier spacing and / or the duration of the TTI may be scalable.

[0041] In some aspects, BS105 may assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RBs)) for downlink (DL) and uplink (UL) transmissions in network 100. DL refers to the transmission direction from BS105 to UE 115, and UL refers to the transmission direction from UE 115 to BS105. The communication may be in the form of a radio frame. A radio frame may be divided into a plurality of subframes or time slots, for example, about 10. Each time slot may also be divided into micro-time slots. In FDD mode, simultaneous UL transmission and DL transmission may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In TDD mode, UL transmission and DL transmission occur in different time periods using the same frequency band. For example, a subframe subset (e.g., a DL subframe) in a radio frame may be used for DL ​​transmission, and another subframe subset (e.g., an UL subframe) in a radio frame may be used for UL transmission.

[0042] DL subframes and UL subframes may also be divided into several zones. For example, each DL subframe or UL subframe may have a predefined zone for the transmission of reference signals, control information, and data. A reference signal is a predetermined signal that facilitates communication between BS105 and UE 115. For example, a reference signal may have a specific pilot pattern or structure, wherein a pilot tone may span an operational BW or frequency band, and each pilot tone is located at a predefined time and a predefined frequency. For example, BS105 may send a cell-specific reference signal (CRS) and / or a channel state information-reference signal (CSI-RS) to enable UE 115 to estimate a DL channel. Similarly, UE 115 may send a sounding reference signal (SRS) to enable BS105 to estimate an UL channel. As further discussed below with respect to the remaining figures, a sidelink UE 115 may send a sidelink reference signal between each other, such as, for example, a sidelink reference signal modeled after a CSI-RS, although other types are also possible.

[0043] The control information may include resource assignments and protocol controls. The data may include protocol data and / or operational data. In some aspects, the BS 105 and the UE 115 may communicate using self-contained subframes. The self-contained subframe may include a portion for DL ​​communication and a portion for UL communication. The self-contained subframe may be DL-centric or UL-centric. A DL-centric subframe may include a DL communication duration that is longer than the UL communication duration. A UL-centric subframe may include a UL communication duration that is longer than the UL communication duration.

[0044] In some aspects, the network 100 may be an NR network deployed on a licensed spectrum. The BS 105 may send synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)) in the network 100 to facilitate synchronization. The BS 105 may broadcast system information associated with the network 100 (e.g., including a master information block (MIB), remaining system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some cases, the BS 105 may broadcast the PSS, SSS, and / or MIB in the form of a synchronization signal block (SSB) over a physical broadcast channel (PBCH), and may broadcast the RMSI and / or OSI over a physical downlink shared channel (PDSCH).

[0045] In some aspects, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a PSS from the BS 105. The PSS may enable synchronization of period timing and may indicate a physical layer identification value. The UE 115 may then receive the SSS. The SSS may enable radio frame synchronization and may provide a cell identification value that may be combined with the physical layer identification value to identify a cell. The PSS and SSS may be located in the center portion of a carrier or at any suitable frequency within a carrier.

[0046] After receiving the PSS and SSS, the UE 115 may receive the MIB. The MIB may include system information for initial network access and scheduling information for RMSI and / or OSI. After decoding the MIB, the UE 115 may receive the RMSI and / or OSI. The RMSI and / or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource sets (CORESET) for physical downlink control channel (PDCCH) monitoring, physical UL control channel (PUCCH), physical UL shared channel (PUSCH), power control, and SRS.

[0047] After obtaining the MIB, RMSI and / or OSI, the UE 115 may perform a random access procedure to establish a connection with the BS 105. In some examples, the random access procedure may be a four-step random access procedure. For example, the UE 115 may send a random access preamble, and the BS 105 may respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, UL grant, temporary cell radio network temporary identifier (C-RNTI) and / or a backoff indicator. Upon receiving the random access response, the UE 115 may send a connection request to the BS 105 and the BS 105 may respond with a connection response. The connection response may indicate contention resolution. In some examples, the random access preamble, the RAR, the connection request, and the connection response may be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure may be a two-step random access procedure, where the UE 115 may send a random access preamble and a connection request in a single transmission, and the BS 105 may respond by sending a random access response and a connection response in a single transmission.

[0048] After establishing the connection, UE 115 may initiate an initial network attachment process with network 100. When UE 115 does not perform active data communication with BS 105 after network attachment, UE 115 may return to an idle state (e.g., RRC idle mode). Alternatively, UE 115 and BS 105 may enter an operational state or an active state, in which operational data may be exchanged (e.g., RRC connected mode). For example, BS 105 may schedule UE 115 for UL communication and / or DL ​​communication. BS 105 may send UL scheduling grant and / or DL ​​scheduling grant to UE 115 via PDCCH. Scheduling grant may be sent in the form of DL control information (DCI). BS 105 may send DL communication signals (e.g., carrying data) to UE 115 via PDSCH according to the DL scheduling grant. UE 115 may send UL communication signals to BS 105 via PUSCH and / or PUCCH according to the UL scheduling grant.

[0049] In some aspects, BS105 may communicate with UE 115 using HARQ technology to improve communication reliability, for example, to provide URLLC services. BS105 may schedule UE 115 to perform PDSCH communication by sending DL grant in PDCCH. BS105 may send DL data packets to UE 115 according to the scheduling in PDSCH. DL data packets may be sent in the form of transport blocks (TBs). If UE 115 successfully receives the DL data packet, UE 115 may send HARQ ACK to BS105. On the contrary, if UE115 fails to successfully receive the DL transmission, UE 115 may send HARQ NACK to BS105. Upon receiving HARQ NACK from UE 115, BS105 may resend the DL data packet to UE 115. The retransmission may include a decoding version of the DL data that is the same as the initial transmission. Alternatively, the retransmission may include a decoding version of the DL data that is different from the initial transmission. The UE 115 may apply soft combining to combine the coded data received from the initial transmission and the retransmission for decoding. The BS 105 and the UE 115 may also apply HARQ to UL communications using a substantially similar mechanism as DL HARQ.

[0050] In some aspects, the network 100 may operate on a system BW or a component carrier (CC) BW. The network 100 may divide the system BW into multiple BWPs (e.g., parts). The BS 105 may dynamically assign the UE 115 to operate on a specific BWP (e.g., a specific part of the system BW). The assigned BWP may be referred to as an active BWP. The UE 115 may monitor the active BWP to find signaling information from the BS 105. The BS 105 may schedule the UE 115 to perform UL or DL ​​communications in the active BWP. In some aspects, the BS 105 may assign a pair of BWPs within the CC to the UE 115 for UL and DL communications. For example, the BWP pair may include a BWP for UL communication and a BWP for DL ​​communication.

[0051] In some aspects, the BS 105 may send a PRACH configuration to the UE 115. The PRACH configuration may indicate a set of ROs in the PRACH configuration. The BS 105 and / or the UE 115 may divide the ROs into different groups, including a first group of ROs configured for PRACH repetition and a second group configured for a single PRACH transmission. In addition to the BS-UE communications as briefly noted above, the various UEs 115 may additionally or alternatively engage in sidelink communications with each other.

[0052] In some aspects, BS 105 may be a 5G NR BS. The 5G NR BS and UE 115 may perform a fallback process in which communication is transferred from UE 115 and the 5G NR BS to UE 115 and the LTE BS. Such a handover process may occur according to voice fallback or emergency fallback and based on load balancing or coverage requirements. In some aspects, when the handover process is unsuccessful, various aspects of the present disclosure provide systems, devices, and methods for transmitting information related to the unsuccessful handover to the LTE BS in a novel manner, so that the LTE BS can then transmit information to the 5G NR BS that originally communicated with the UE 115. In this regard, the 5G NR BS may change various communication protocols, steps, or parameters to optimize future fallback processes.

[0053] Figure 2 1 illustrates a communication scenario involving a UE 115, one or more BSs 105, and a control plane 125 according to some aspects of the present disclosure. Figure 2 The described scenario may involve mobility robustness optimization (MRO) enhancements for inter-system handover voice fallback. In some aspects, a handover from a base station (BS) of one RAN type to another base station of a different RAN type may be optimized. Figure 2 The scenario shown and described may correspond to a voice fallback scenario. Figure 2 The UE 115 shown can wirelessly send and / or receive data to facilitate a voice call. In some aspects, the voice call may include communicating with Figure 2 Wireless communications with the BS 105 are shown, thereby facilitating communications with another UE or any other wireless communications device.

[0054] In some aspects, UE 115 may have established wireless communication with BS 105a as shown. For example, UE 115 may send and / or receive data related to a voice call facilitated by BS 105a with another wireless communication device.

[0055] BS105a may send a mobility command 210 to UE 115. In some aspects, the mobility command may alternatively be referred to as a disconnect command or any other suitable term. In some aspects, BS105a may include a base station capable of facilitating wireless communications according to a fifth generation new radio (5G) protocol. In this way, BS105a may be referred to as a next generation radio access technology network (NG-RAN) BS. BS 105a may correspond to or communicate with a 5G core network. In such scenarios, BS105a may be referred to as an independent BS. In some aspects, BS105a may correspond to or communicate with a fourth generation (4G) or long term evolution (LTE) core network. In such scenarios, BS105a may be referred to as a non-independent BS.

[0056] The mobility command 210 may include any suitable command. For example, in aspects where BS 105a is a standalone BS, BS 105a may not be able to support NR-based voice calls. In such cases, in response to a request by UE 115 to establish a voice call, BS 105a may send a mobility command 210 to UE 115. In other examples, communications may be transferred from a 5G BS to a 4G BS for emergency services, or in response to load balancing or coverage issues. The mobility command 210 may initiate an inter-system fallback, in which communications between UE 115 and NG-RAN BS 105a are terminated, and communications between UE 115 and E-UTRAN (such as BS 105b or BS 105c) are established.

[0057] In some aspects, the inter-system fallback may occur when the UE 115 is in a connected mode (e.g., RRC_CONNECTED) or when the UE 115 is in an idle mode (e.g., RRC_IDLE). In some aspects, the inter-system fallback procedure performed when the UE 115 is in the connected mode is referred to as a handover procedure or handover. In some aspects, the inter-system fallback procedure performed when the UE 115 is in the idle mode is referred to as a redirection procedure or redirection.

[0058] In some aspects, the mobility command 210 may include a mobility command message from the NR. The command message may include a voice fallback indication. In some aspects, the voice fallback indication may indicate that the UE 115 should perform a voice fallback procedure. In some aspects, the mobility command message from the NR may alternatively include other fallback indications, including fallback indications related to emergency services, load balancing, or coverage issues.

[0059] In some aspects, the mobility command 210 may include various data. For example, in addition to the fallback indication, the mobility command 210 may include a target radio access technology (RAT) type, such as 4GBS, LTE BS, Evolved Universal Terrestrial Radio Access Evolved Packet Core (E-UTRA / EPC), Universal Terrestrial Radio Access Frequency Division Duplex (UTRA-FDD), or any other type of RAT. In some aspects, the mobility command 210 may additionally include other data related to the target RAT, such as a message container.

[0060] like Figure 2 As shown, in some aspects, UE 115 may send a connection request 212, such as a RACH request, to a target BS. In some aspects, the specific target BS may be indicated by BS 105a. In some aspects, only the type of target BS may be specified. Figure 2210, BS 105b may correspond to a BS specified by BS 105a in mobility command 210 or a type of BS specified by BS 105a in mobility command 210. In some cases, a connection request from UE 115 to a new target BS may fail. For example, wireless communication may not be established between UE 115 and BS 105b. In some aspects, communication between UE 115 and BS 105b may be terminated based on voice fallback. Therefore, UE 115 may be configured to retry establishing wireless communication with BS 105b by, for example, sending an additional connection request. In some aspects, in response to the unsuccessful connection request 212, UE 115 may identify another target BS (e.g., a BS of the type specified by mobility command 210) and send another connection request 214.

[0061] The connection request 214 may be similar to the connection request 212. In some aspects, the connection request 214 may comprise a RACH request.

[0062] After successfully establishing wireless communication between UE 115 and BS 105c, BS 105c may send a request for information 216 to UE 115. The request 216 may include a request for any suitable information. For example, the request for information 216 may include a request for information related to any previous failed connection attempts or information related to mobility commands from a previous BS. In some aspects, the request for information 216 may include a request for information stored in a memory of UE 115 related to failed connection requests to BS 105b. In some aspects, the request for information may include a request for information included in the disconnect command 210. The request for information 216 may include a request for any suitable report, such as a reference to a request for ... Figure 5 Any of the reports listed.

[0063] In response to the request for information 216, the UE 115 may send a report 218 to the BS 105c. In some aspects, the UE 115 may generate the report 218 by accessing information from a memory of the UE 115, including any of the information described above. The report 218 may include a fallback indication. The fallback indication may indicate the type of fallback process that allows disconnection from the BS 105a and subsequent connection to the BS 105c. For example, if the fallback is due to a voice fallback, the fallback indication may be a voice fallback indication. The fallback indication may also correspond to an emergency fallback, a fallback related to load balancing, a fallback related to, for example, a coverage issue with the BS 105a, or any other type of fallback. For each of these fallback types, a unique fallback indication may be included in the report 218, as will be referenced below. Figure 5In this regard, BS 105c may be configured to receive report 218 including a unique fallback indication indicating the type of cross-RAT fallback that may have been initiated by BS 105a. In some aspects, report 218 may be a cross-RAT report configured to be received by an LTE BS.

[0064] After BS 105c receives report 218, BS 105c may send signal 220 including report 218 or an element of report 218 to control plane 125. The control plane may include multiple components or aspects of the core network, such as MME, AMF, SMF, UPF, IMS, SGW / PGW, or any other suitable component. In some examples, a portion of control plane 125 may be dedicated to facilitating communication of LTE base stations, and a portion of control plane 125 may be dedicated to facilitating communication of 5G base stations. Another portion of control plane 125 may be dedicated to facilitating communication between LTE base stations and 5G base stations.

[0065] exist Figure 2 In the example shown, the control plane 125 may forward the signal 220 to the BS 105a as a signal 222. In some aspects, the BS 105a may perform various processing of the received signal 222 and may perform optimization based on the information in the signal 222. Various aspects of the present disclosure advantageously enable information such as the fallback indication described in the reference report 218 to be quickly and efficiently delivered back to the BS 105a. The optimization performed by the BS 105a may include selecting a different target BS to transfer the UE 115 to the target BS during a future handover or redirection process. Additional optimizations may include specifying different types of target BSs. Optimization may also be performed based on the type of fallback indication within the report (including whether the fallback indication is related to voice, emergency, load balancing, or coverage issues).

[0066] In some aspects, the control plane 125 may additionally forward the signal 220 to the BS 105b as the signal 224. In this regard, the BS 105b may additionally perform various optimization procedures to improve the quality or efficiency of communications and / or handover or redirection procedures involving the BS 105b.

[0067] Figure 3 300 is a block diagram of an exemplary UE 300 according to some aspects of the present disclosure. The UE 300 may be as described in reference Figure 1UE 115 discussed and shown in multiple figures. As shown, UE 300 may include a processor 302, a memory 304, a reporting module 308, a transceiver 310 including a modem subsystem 312 and a radio frequency (RF) unit 314, and one or more antennas 316. These elements may be coupled to each other. The term "coupled" may refer to being directly or indirectly coupled or connected to one or more intervening elements. For example, these elements may communicate directly or indirectly with each other, such as via one or more buses.

[0068] The processor 302 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 302 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0069] The memory 304 may include cache memory (e.g., cache memory of the processor 302), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state memory devices, hard drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In one aspect, the memory 304 includes a non-transitory computer-readable medium. The memory 304 may store or have recorded thereon instructions 306. The instructions 306 may include instructions that, when executed by the processor 302, cause the processor 302 to perform the various aspects of the present disclosure (e.g., Figure 2 and Figures 5 to 10 Instructions 306 may also be referred to as codes, which may be broadly interpreted to include any type of computer-readable statements.

[0070] The reporting module 308 may be implemented via hardware, software, or a combination thereof. For example, the reporting module 308 may be implemented as a processor, circuit, and / or instruction 306 stored in the memory 304 and executed by the processor 302. In some aspects, the reporting module 308 may be integrated within the modem subsystem 312. For example, the reporting module 308 may be implemented by a combination of software components (e.g., executed by a DSP or general purpose processor) and hardware components (e.g., logic gates and circuits) within the modem subsystem 312. The reporting module 308 may communicate with one or more components of the UE 300 to implement various aspects of the present disclosure, such as, Figure 2 and Figures 5 to 10 all aspects.

[0071] The reporting module 308 may be configured to perform various functions related to generating reports corresponding to a fallback procedure between the UE 300 and one or more BSs (e.g., BS 400 described below). Such functions may include identifying a target BS (such as an LTE BS to which a connection request is to be transmitted) during the fallback procedure, determining whether a connection is established with the target BS, storing information related to a mobility command or a failed connection request, identifying an alternative target BS, generating a report based on the stored information, and sending the report. In some aspects, the reporting module 308 may additionally receive and / or process information requests or other signals from the BS. The reporting module 308 may generate a variety of reports. For example, the reporting module 308 may be configured to generate a radio link failure (RLF) report, a connection establishment failure (CEF) report, an inter-RAT report, an inter-RLF report, an inter-RAT CEF report, a RACH report, a successful handover report, a mobility history report, an SHR report, or any other suitable report.

[0072] As shown, the transceiver 310 may include a modem subsystem 312 and an RF unit 314. The transceiver 310 may be configured to communicate bidirectionally with other devices, such as the BS 105. The modem subsystem 312 may be configured to modulate and / or encode data from the memory 304 and / or the reporting module 308 according to a modulation and coding scheme (MCS) (e.g., a low-density parity check (LDPC) decoding scheme, a turbo decoding scheme, a convolutional decoding scheme, a digital beamforming scheme, etc.). The RF unit 314 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated / encoded data (e.g., channel sensing reports, PUCCH UCI, PUSCH data, etc.) transmitted from another source, such as the UE 115, the BS 105, or the anchor. The RF unit 314 may also be configured to perform analog beamforming in conjunction with digital beamforming. Although shown as being integrated together in the transceiver 310, the modem subsystem 312 and the RF unit 314 may be separate devices that are coupled together at the UE 300 to enable the UE 300 to communicate with other devices.

[0073] The RF unit 314 may provide modulated and / or processed data (e.g., data packets (or more generally, data messages that may include one or more data packets and other information)) to the antenna 316 for transmission to one or more other devices. The antenna 316 may also receive data messages sent from other devices. The antenna 316 may provide the received data messages for processing and / or demodulation at the transceiver 310. The transceiver 310 may provide the demodulated and decoded data (e.g., RRC tables for channel access configuration, scheduling grant, channel access configuration activation, timing advance configuration, RRC configuration, PUSCH configuration, SRS resource configuration, PUCCH configuration, BWP configuration, PDSCH data, PDCCH DCI, side link configuration, etc.) to the reporting module 308 for processing. The antenna 316 may include multiple antennas of similar design or different designs in order to maintain multiple transmission links.

[0074] In one aspect, the UE 300 may include multiple transceivers 310 that implement different RATs (e.g., NR and LTE). In one aspect, the UE 300 may include a single transceiver 310 that implements multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 310 may include various components, where different combinations of components may implement different RATs.

[0075] Figure 4 is a block diagram of an exemplary BS 400 according to some aspects of the present disclosure. BS 400 may be such as Figure 14. As shown, BS 400 may include a processor 402, a memory 404, a reporting module 408, a transceiver 410 including a modem subsystem 312 and an RF unit 414, and one or more antennas 414. These elements may be coupled to each other. The term "coupled" may refer to being directly or indirectly coupled or connected to one or more intervening elements. For example, these elements may communicate directly or indirectly with each other, such as via one or more buses.

[0076] The processor 402 may have various features that are specific types of processors. For example, these features may include a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 402 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0077] Memory 404 may include cache memory (e.g., cache memory of processor 402), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid-state memory devices, one or more hard disk drives, memristor-based arrays, other forms of volatile and nonvolatile memory, or a combination of different types of memory. In some aspects, memory 404 may include non-transitory computer-readable media. Memory 404 may store instructions 406. Instructions 406 may include instructions that, when executed by processor 402, cause processor 402 to perform the operations described herein (e.g., Figure 2 and Figures 5 to 10 Instructions 406 may also be referred to as program code. The program code may cause the wireless communication device to perform these operations, for example by causing one or more processors (such as processor 402) to control or command the wireless communication device to do so. The terms "instructions" and "code" should be interpreted broadly to include any type of computer-readable statements. For example, the terms "instructions" and "code" may refer to one or more programs, routines, subroutines, functions, procedures, etc. "Instructions" and "code" may include a single computer-readable statement or multiple computer-readable statements.

[0078] The reporting module 408 may be implemented via hardware, software, or a combination thereof. For example, the reporting module 408 may be implemented as a processor, circuit, and / or instruction 406 stored in the memory 404 and executed by the processor 402. In some examples, the reporting module 408 may be integrated within the modem subsystem 412. For example, the reporting module 408 may be implemented by a combination of software components (e.g., executed by a DSP or general purpose processor) and hardware components (e.g., logic gates and circuits) within the modem subsystem 412. The reporting module 408 may communicate with one or more components of the BS 400 to implement various aspects of the present disclosure, such as, Figure 2 and Figures 5 to 10 all aspects.

[0079] The reporting module 408 may be configured to perform various functions related to generating and / or conveying information or data related to a fallback process for a UE (e.g., UE 300 and / or UE 115) communicating with the BS 400. Such functions may include generating and sending a mobility command to the UE. In some aspects, the reporting module 408 may be additionally configured to perform generating an information request for sending to the UE. The information request may include a request for any suitable information. For example, the requested information may include information related to any previous failed connection attempts or information related to a mobility command from another BS. In some aspects, the request for information may include a request for information related to a failed connection request to another BS or any other information. In some aspects, the reporting module 408 may be additionally configured to receive a report containing any of the information from the UE.

[0080] In some aspects, reporting module 408 may additionally be configured to send reports to a component of a core network or control plane (e.g., control plane 125) in communication with BS 400. In some aspects, reporting module 408 may additionally be configured to perform various processing of reports (e.g., reports received from UEs or reports generated by reporting module 408).

[0081] In some aspects, reporting module 408 may additionally receive reports from another BS or core network component. For example, reporting module 408 (e.g., reporting module of BS 105a) may receive reports after the fallback process is completed. In some aspects, reporting module 408 may analyze and / or process the reports and determine various optimization functions to be performed by BS 400 and / or commands for optimization of other components of the wireless communication system.

[0082] As shown, the transceiver 410 may include a modem subsystem 412 and an RF unit 414. The transceiver 410 may be configured to communicate bidirectionally with other devices, such as the UE 115 and / or the BS 400 and / or another core network element. The modem subsystem 412 may be configured to modulate and / or encode data according to an MCS (e.g., an LDPC decoding scheme, a turbo decoding scheme, a convolutional decoding scheme, a digital beamforming scheme, etc.). The RF unit 414 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated / encoded data (e.g., RRC tables for channel access configuration, scheduling grants, channel access configuration activation, RRC configuration, PDSCH data, PDCCH DCI, RACH preamble assignments, random access messages, sidelink resource pool configurations, sidelink reference signal parameter configurations, etc.) from the modem subsystem 412 (on outbound transmissions) or from another source, such as the UE 115. RF unit 414 may also be configured to perform analog beamforming in conjunction with digital beamforming.Although shown as integrated together in transceiver 410, modem subsystem 412 and / or RF unit 414 may be separate devices coupled together at BS 400 to enable BS 400 to communicate with other devices.

[0083] The RF unit 414 may provide modulated and / or processed data (e.g., data packets (or more generally, data messages that may include one or more data packets and other information)) to the antenna 414 for transmission to one or more other devices. The antenna 414 may also receive data messages sent from other devices and provide the received data messages for processing and / or demodulation at the transceiver 410. The transceiver 410 may provide the demodulated and decoded data (e.g., PRACH messages, channel sensing reports, PUCCH UCI, PUSCH data, etc.) to the reporting module 408 for processing. The antenna 414 may include multiple antennas of similar design or different designs in order to maintain multiple transmission links.

[0084] In one aspect, BS 400 may include multiple transceivers 410 that implement different RATs (e.g., NR and LTE). In one aspect, BS 400 may include a single transceiver 410 that implements multiple RATs (e.g., NR and LTE). In one aspect, transceiver 410 may include various components, where different combinations of components may implement different RATs. As will be described in more detail below, a UE (e.g., UE 115 and / or UE 300) may send a report to a target BS (e.g., BS 105c and / or BS 400) during a fallback process. The report may include various data related to the handover or redirection of the UE, including specifying a previous BS, a target BS, a backup BS, or any other wireless communication device, and including various types of fallback indications.

[0085] Figure 5 is a graphical representation of a report 500 in accordance with aspects of the present disclosure. Report 500 may be any suitable type of report. As described in more detail below, report 500 may be a radio link failure (RLF) report, a connection establishment failure (CEF) report, an inter-RAT report, an inter-RLF report, an inter-RAT CEF report, a RACH report, a successful handover report, a mobility history report, or any other suitable report. In some aspects, report 500 may be some aspects or fields of any of these reports. Report 500 may be sent between any suitable wireless communication devices. For example, report 500 may be sent from [list all the different directions this thing can go]

[0086] Report 500 may include field 502. Field 502 may correspond to a previous cell. For example, the previous cell may specify a BS that transmitted a mobility command to the UE. Figure 2 , the previous cell may correspond to BS105a.

[0087] Report 500 may also include field 504. This field may correspond to a failed cell. For example, a failed cell may specify a BS to which a UE (eg, UE 115) first transmitted a connection request but to which communication was not established. Figure 2 , the failed cell may correspond to BS105b.

[0088] Report 500 may also include field 506. This field may correspond to a reconnecting cell. For example, the reconnecting cell may specify a BS to which a UE (e.g., UE 115) transmits a connection request after attempting to connect to the failed cell of field 504 and the connection fails. In some aspects, the reconnecting cell may be a BS with which UE 115 successfully establishes a connection. Figure 2 , the reconnecting cell may correspond to BS105c.

[0089] Report 500 may also include field 508. Field 508 may specify a handover report type. In some aspects, the handover report type may indicate the reason for the handover reporting process. For example, if a handover is performed with the wrong cell or BS, the handover report type field may include possible values ​​indicating that the handover was performed too early or too late. The handover report type field may also include values ​​corresponding to inter-system unnecessary handover or inter-system back-and-forth handover scenarios. It should also be noted that field 508 may also specify a redirection report type, for example, in a scenario where the UE is in RRC idle or inactive mode.

[0090] Report 500 may also include field 510. Field 510 may specify whether a speech fallback indication is included in the report. For example, if a speech fallback indication is included, the field may indicate that the fallback process corresponding to the report is specifically due to speech fallback.

[0091] In some aspects, a report 500 corresponding to an evolved packet system (EPS) fallback may be generated. In such cases, the report 500 may include multiple fields to indicate the type of EPS fallback. For example, field 510 may specify whether the EPS fallback corresponds to a voice fallback. However, as shown in field 512, additional fields corresponding to indications of other fallback types may be included. For example, an additional field corresponding to an emergency fallback indication may be provided, which may be populated with a true or false value. Similarly, an additional field corresponding to a fallback indication corresponding to load balancing may be provided, and an additional field corresponding to a fallback indication involving coverage issues may be provided. Additional fields may be provided for various additional fallback indication types.

[0092] Figure 5 Additionally depicted are multiple values ​​for filling fields 502 to 510. These example values ​​may correspond to various communication scenarios. In one aspect, row 522 includes a set of exemplary values ​​for each of the fields of report 500. For example, previous cell field 502 may be designated as NR cell A, indicating that the original cell is an NR BS. In some aspects, previous cell field 502, failed cell field 504, and / or reconnected cell field 506 may be filled with the corresponding cell global identifier (CGI) of the corresponding BS of each field.

[0093] Continuing with the example of row 522, the failed cell field 504 may be designated as LTE cell B, and the reconnected cell field 506 may be designated as NR cell A. The handover report type field 508 may be designated as "premature HO", indicating that the handover process was completed prematurely. The voice fallback indication is set to false, indicating that the EPS fallback of row 522 is not voice fallback.

[0094] On the other hand, row 524 includes an additional set of exemplary values. Previous cell field 502 is set to NR cell A, failed cell field 504 may be specified as LTE cell B, and reconnect cell field 506 may be specified as NR cell A. Similar to row 522, handover report type field 508 may be specified as "premature HO". Voice fallback indication is set to true, indicating that the EPS fallback of row 522 is voice fallback.

[0095] On the other hand, row 526 includes an additional set of exemplary values. Previous cell field 502 is set to NR cell A, failed cell field 504 may be specified as LTE cell B, and reconnect cell field 506 may be specified as LTE cell C. Handover report type field 508 may be specified as "HO to wrong cell". Voice fallback indication is set to false, indicating that the EPS fallback of row 522 is not voice fallback.

[0096] On the other hand, row 528 includes an additional set of exemplary values. Previous cell field 502 is set to NR cell A, failed cell field 504 may be specified as LTE cell B, and reconnect cell field 506 may be specified as LTE cell C. Handover report type field 508 may be specified as "HO to wrong cell". Voice fallback indication is set to true, indicating that the EPS fallback of row 522 is voice fallback.

[0097] It should be understood that fields 502 through 510, as well as any additional fields (e.g., as shown in field 512), may include any suitable value or combination of values. Additional aspects of reports such as report 500 are described in more detail below. Figure 5 The illustrated and described report 500 may provide an example of information or data transmitted between wireless communication devices of the disclosed network. As will be explained below, aspects of the report 500 may be transmitted from a UE to a target BS, a backup BS, or any other BS, as described below.

[0098] Figure 6 6 is a signaling diagram 600 of communications between UE 115, NG-RAN BS 605, E-UTRAN BS 625b, MME 635, and AMF 645 according to aspects of the present disclosure. The signaling diagram 600 may be implemented by any suitable wireless communication device. In some aspects, UE 115 may utilize one or more components such as Figure 3The processor 302, memory 304, reporting module 308, transceiver 310, modem 312, and one or more antennas 316 are shown to perform any of the actions in the signaling diagram 600. In some aspects, the NG-RAN BS 605 can be similar to the BS 105 and / or BS 400 described previously. For example, the NG-RAN BS 605 can utilize one or more components such as Figure 4 4. The processor 402, memory 404, reporting module 408, transceiver 410, modem 412, and one or more antennas 414 are shown. In some aspects, E-UTRAN BS 625a and / or E-UTRAN BS 625b may be similar to BS 105 and / or BS 400 described previously. For example, E-UTRAN BS 625a and / or E-UTRAN BS 625b may utilize one or more components such as Figure 4 The processor 402, memory 404, reporting module 408, transceiver 410, modem 412 and one or more antennas 414 are shown. As illustrated, the signaling diagram 600 includes several of the enumerated actions, but Figure 6 The various aspects of the invention may include additional actions before, after, and between the actions listed. In some aspects, one or more of the actions listed may be omitted, combined together, or performed in a different order.

[0099] Aspects of the signaling diagram 600 may describe an inter-system fallback process. Figure 2 As mentioned, the inter-system fallback may occur when the UE 115 is in a connected mode (e.g., RRC_CONNECTED) or when the UE 115 is in an idle mode or an inactive mode (e.g., RRC_IDLE). In some aspects, the inter-system fallback procedure performed when the UE 115 is in a connected mode is referred to as a handover procedure or handover. In some aspects, the inter-system fallback procedure performed when the UE 115 is in an idle mode is referred to as a redirection procedure or redirection. Various aspects of the signaling diagram 600 will first be described with reference to the handover procedure, and then various aspects of the signaling diagram will be described with reference to the redirection procedure.

[0100] At action 602, the NG-RAN BS 605 may send a mobility command to the UE 115. The NG-RAN BS 605 may be a 5G base station, including an independent or non-independent BS. The mobility command described with reference to action 602 may be substantially similar to that described with reference to Figure 2 Described mobility command 210. The mobility command of action 602 may initiate an inter-system fallback, wherein communications between the UE 115 and the NG-RANBS 605 are terminated and communications between the UE 115 and the E-UTRAN are established.

[0101] In some aspects, the mobility command of action 602 may include a mobility command message from the NR. The command message may include a voice fallback indication. In some aspects, the voice fallback indication may indicate that the UE 115 should perform a voice fallback procedure. In some aspects, the mobility command message from the NR may alternatively include other fallback indications, including fallback indications related to emergency services, load balancing, or coverage issues. In some aspects, although aspects of the present disclosure are applicable to any type of fallback indication as disclosed herein, the discussion below is particularly focused on the voice fallback procedure, although any aspects or principles described with reference to the voice fallback procedure may be equally applicable to any type of fallback procedure.

[0102] In some aspects, the mobility command may include various data. For example, in addition to the fallback indication, the mobility command may include a target RAT type, such as 4G BS, LTE BS, E-UTRA / EPC, UTRA-FDD, or any other type of RAT. In some aspects, the mobility command may additionally include other data related to the target RAT, such as a message container.

[0103] At action 604, the UE 115 may identify the target BS. In some aspects, action 604 may additionally include storing information from the mobility command 602 in a memory of the UE 115. For example, at action 604, the UE 115 may store a fallback indication included in the mobility command 602, the fallback indication specifying whether the fallback involves voice fallback, emergency fallback, or a fallback related to load balancing or coverage. In some aspects, the UE 115 may store data, such as an indication of the target RAT, the type of the target RAT, or a message or message container related to the target RAT. In some aspects, the information from the mobility command may be stored in a variable.

[0104] In some aspects, the UE 115 may identify the target RAT in any suitable manner. For example, the UE 115 may identify the target RAT based on the RAT specified by the BS 605 in the mobility command 602 at action 604. In some aspects, the UE 115 may select the target RAT based on the type of RAT specified by the BS 605 in the mobility command 602.

[0105] At act 606, the UE 115 sends a connection request to the E-UTRAN BS 625a. In some aspects, the connection request may include a RACH request.

[0106] At action 608, UE 115 may determine that the connection between UE 115 and E-UTRAN BS 625a is unsuccessful. UE 115 may be configured to make this determination in any manner. For example, in response to not receiving a response signal from E-UTRAN BS 625a, UE 115 may determine that the connection to E-UTRAN BS 625a has failed.

[0107] At act 610, UE 115 may store information related to the failure to establish a connection with E-UTRAN BS 625a. The information may include any suitable data, including, for example, metrics related to channel quality between UE 115 and E-UTRAN BS 625a, context information related to the connection request (such as the time of the request, the content of the request, or other specified parameters of the request), or any other information. In some aspects, the information stored by UE 115 at act 610 may include the mobility command or the previously described act 602. Figure 2 Any information included in the mobility command 210.

[0108] In some aspects, information related to the failed connection may be stored in a variable (e.g., VarRLF-Report). In this regard, the UE 115 may access the VarRLF report corresponding to the NG-RAN BS 625a to obtain information to be included in the response to the request for information from the E-UTRAN BS 625c. Any information within the VarRLF report may be selected and included in the report generated at action 612 described below.

[0109] At action 612, UE 115 may identify the backup target E-UTRAN BS. For example, UE 115 may identify E-UTRAN BS 625b as the backup target E-UTRAN BS. As described with reference to action 604, this may be accomplished in any suitable manner, including based on a RAT specified by BS 605 in mobility command 602 (such as a backup RAT) or based on the type of RAT specified by BS 605 in mobility command 602.

[0110] At act 614, UE 115 may send a connection request to the backup target RAT identified at act 612. As described with reference to act 606, the connection request may include a RACH request or any other request.

[0111] At action 616, the E-UTRAN BS 625b may send a request for information to the UE 115. In some aspects, in response to establishing a connection between the UE 115 and the E-UTRAN BS 625b, the E-UTRAN BS 625b may send a request for information to the UE 115. The request for information may specify any suitable information. For example, the request for information may include a request for information related to any previous failed connection attempts or information related to mobility commands from a previous BS. In some aspects, the request for information at action 616 may include a request for information related to failed connection requests to the E-UTRAN BS 625a stored at action 610. In some aspects, the request for information may include a request for information from the mobility command 602. In other aspects, the request for information may include a request for information related to or resulting from any of actions 602 to 614.

[0112] At act 618, the UE 115 may access the requested information. In some aspects, the UE 115 may access a memory of the UE 115 and retrieve the requested information.

[0113] At act 620, UE 115 generates a report. In some aspects, the report may be based on or include any of the information requested by E-UTRAN BS 625b, including any of the information described with reference to act 616. In some aspects, the report generated at act 620 may include a radio link failure (RLF) report. The RLF report may include any suitable data. In some aspects, the RLF report may include reference to Figure 5 Any of the data or data types shown and described. It is noted that the RLF report may include a backoff indication. Figure 5 , the fallback indication may correspond to a voice fallback indication. In some aspects, the RLF report may additionally or alternatively include different types of fallback indications, such as an emergency fallback indication, a fallback indication due to load balancing, a fallback indication due to coverage issues, or any other type of fallback indication. In some aspects, the report generated by the UE 115 at action 620 may be referred to as an inter-RAT report or an inter-RAT RLF report. In this regard, the report generated at action 620 may be a report for an LTE BS, such as an E-UTRAN BS 625b containing information related to a handover from a 5G BS (e.g., NG-RAN BS 605) to an LTE BS (E-UTRAN BS 625b).

[0114] In some aspects, the report generated at action 620 may include an indication of the NG-RAN BS 605. The report may be stored and / or sent as an octet string or 8-bit bytes (e.g., with reference to action 622). In some aspects, a field of the report may indicate the primary cell (PCell) in which the RLF was detected and / or the source PCell of the failed handover. The report may include a field that includes the measurement results and is set to the value of the RLF report. In some aspects, the report may include the time elapsed since the last radio link failure or handover failure associated with the NG-RAN BS 605, the E-UTRAN BS 625a, and / or the E-UTRAN BS 625b.

[0115] In some aspects, the report generated at act 620 may also include information related to the interruption time. For example, the report may include the handover interruption time. In this regard, the report may include a measure of the time between receipt of a successful RACH on a target cell (e.g., E-UTRAN BS 625b) corresponding to a mobility command from the NR.

[0116] At action 622, the report generated at action 620 may be sent to the E-UTRAN BS 625b. The report may be sent in any suitable manner or according to any wireless communication scheme or schedule. In some aspects, the E-UTRAN BS 625b may be configured to, in response to receiving the report at action 622, send an indication to the UE 115 that the report was successfully received. In this regard, the UE 115 may be configured to receive the indication. Then, in response to receiving the indication that the report was successfully received by the E-UTRAN BS 625b, the UE 115 may discard or otherwise delete the report from the memory of the UE 115. In some aspects, the UE 115 may determine that the report was successfully received in any other manner. In some aspects, it may be determined that the report was successfully sent and received, as confirmed by a lower layer.

[0117] At action 624, the E-UTRAN BS 625b may send the eNB configuration to a mobility management entity (MME) 635. The MME 635 and the access and mobility management function (AMF) 645 may be components of the network core. In some aspects, the MME 635 and 645 may be control planes (such as reference Figure 2 In some aspects, the MME 635 and / or the AMF 645 may be in wireless or physical communication with any of the BSs disclosed herein. For example, Figure 6As shown, the E-UTRAN BS 625b may send the eNB configuration to the MME 635 via a wireless connection or a wired connection. Similarly, the MME 635 may be wirelessly connected or wired to any of the NG-RAN 605, the E-UTRAN BS 625a, or any other BS. Information may be transferred to and / or from any of the NG-RAN 605, the E-UTRAN BS 625a, and / or the E-UTRAN BS 625b via the S1 interface. The eNB configuration may include any of the information reported as described with reference to actions 620 to 622.

[0118] At action 626, the MME 635 may send a cross-RAT signal to the AMF 645. In some aspects, the cross-RAT signal may be an N26 message. In some aspects, the cross-RAT signal may be sent via an N26 interface. The N26 interface may facilitate communication between wireless communication devices of different communication protocols. For example, the N26 message may facilitate communication between a 5G wireless communication device (e.g., NG-RAN BS 605) and an LTE wireless communication device (e.g., E-UTRAN BS 625b). In this regard, the cross-RAT signal of action 626 may include any information included in the information reported as described with reference to actions 620 to 622.

[0119] At action 628, a report may be generated and sent from the AMF 645 to the NG-RAN BS 605. In some aspects, the report of action 628 may be the same as the report described with reference to actions 620 through 622. In some aspects, the report may be a separate report generated by the AMF 645, but may include any or all of the information of the reports described with reference to actions 620 through 622.

[0120] As mentioned previously, the redirection process will now be described with reference to Figure 6 Aspects of signaling diagram 600.

[0121] At action 602, the NG-RAN BS 605 may send a mobility command to the UE 115. The mobility command of action 602 may also initiate an inter-system fallback, wherein communication between the UE 115 and the NG-RAN BS 605 is terminated and communication between the UE 115 and the E-UTRAN is established. For the redirection process, the mobility command of action 602 may be an RRC release message. In some aspects, the UE 115 may be in an RRC connected mode and may transition to an RRC idle mode in response to receiving the RRC release message at action 602. The RRC release message may include any of the data or information described above with reference to action 602 of the handover process. For example, the RRC release message may include any type of fallback indication previously described. In some aspects, the RRC release message of action 602 may be sent to the UE 115, indicating that the UE 115 transitions to the RRC idle mode due to voice fallback.

[0122] At action 604, UE 115 may identify a target BS. Action 604 may include substantially similar steps with respect to the redirection process. For example, UE 115 may search for and identify a target BS. As opposed to a target NR BS, the target BS may be an LTE BS. For example, an LTE BS may facilitate voice communications for UE 115.

[0123] At action 606, the UE 115 sends a connection request to the E-UTRAN BS 625a. In some aspects, the connection request may include a RACH request. With respect to the redirection process, the connection request to the E-UTRAN BS 625a may be substantially similar and may be referred to as a redirection.

[0124] At act 608, UE 115 may determine that the connection between UE 115 and E-UTRAN BS 625a is unsuccessful. Act 608 may be substantially similar to the handover process described previously with reference to the redirection process.

[0125] At action 610, the UE 115 may store information related to the failure to establish a connection with the E-UTRAN BS 625a. Action 610 may be similar to the handover process described previously with reference to the redirection process. In some aspects, the data stored at action 610 of the redirection process may be stored in a different variable, such as a variable or field of a connection establishment failure (CEF) report.

[0126] At act 612, UE 115 may identify an alternate target E-UTRAN BS. Act 612 may be substantially similar to the handover process described previously with reference to the redirection process.

[0127] At act 614, UE 115 may send a connection request to the backup target RAT identified at act 612. With respect to the redirection process, the connection request to E-UTRAN BS 625b may be substantially similar to the handover process.

[0128] At action 616, the E-UTRAN BS 625b may send a request for information to the UE 115. Action 616 may be substantially similar to the handover process described previously with reference to the redirection process.

[0129] At act 618, UE 115 may access the requested information. With reference to the redirection process, act 618 may be substantially similar to the handover process described previously.

[0130] At action 620, the UE 115 generates a report. With reference to the redirection process, action 620 may be similar. For the redirection process, the report generated at action 620 may be referred to as a CEF report. The CEF report may include any of the data or information described above with reference to the report of action 620. In addition, the CEF report may include an indicator that the redirection failed due to fallback. The CEF report may also include an indicator specifying the fallback type that triggered the redirection (e.g., voice, emergency, load balancing, coverage issues, etc.). In some aspects, the CEF report may include a cell global identifier (CGI) of the NG-RAN BS 605. The CEF report may also include a reason for the redirection failure regarding action 606. In some aspects, if an RRC release is triggered for the purpose of redirecting to an E-UTRA cell due to a voice fallback indication, the report may include a metric corresponding to the time between the RRC release and a successful RACH on the target E-UTRA cell (e.g., E-UTRAN BS 625b).

[0131] At action 622, the report generated at action 620 may be sent to the E-UTRAN BS 625b. With reference to the redirection process, action 620 may be similar. Action 620 may be sent to the E-UTRAN BS 625b at any suitable time. For example, the report may be sent to the E-UTRAN BS 625b upon expiration of various timers. For example, the report may be sent to the E-UTRAN BS 625b upon expiration of any of the timers T300, T319, or T320.

[0132] At action 624, the E-UTRAN BS 625b may send the eNB configuration to the mobility management entity (MME) 635. With reference to the redirection procedure, action 624 may be substantially similar to the handover procedure described previously.

[0133] At action 626, the MME 635 may send an N26 message to the AMF 645. With reference to the redirection procedure, action 626 may be substantially similar to the handover procedure described previously.

[0134] At action 628, a report may be generated and sent from the AMF 645 to the NG-RAN BS 605. With reference to the redirection procedure, action 628 may be substantially similar to the handover procedure described previously.

[0135] The NG-RAN BS 605 may perform various processing on the report received at action 628, and may perform optimizations based on the information in the report. Aspects of the present disclosure advantageously enable the information included in the report described with reference to actions 620 to 622 to be quickly and efficiently delivered back to the NT-RAN BS 605. The optimizations performed by the NG-RAN BS 605 based on the information in the report received at action 628 may include selecting a different target E-UTRAN BS to indicate an increased likelihood of a successful connection in a subsequent mobility command. Additional optimizations may include specifying different types of target BSs. Optimizations may also be performed based on the type of fallback indication within the report, including whether the fallback indication is related to voice, emergency, load balancing, or coverage issues. With reference to the redirection process, action 628 may be substantially similar.

[0136] Figure 7 700 is a signaling diagram of communications between a UE 115, an NG-RAN BS 705a, an E-UTRAN BS 725, and an NG-RAN 705b in accordance with aspects of the present disclosure. According to aspects of the present disclosure, the signaling diagram 700 may illustrate a communication scenario in which a connection request to a target BS (e.g., E-UTRAN BS 725) fails, no suitable backup BS is identified, and the UE instead initiates communications with the NG-RAN BS.

[0137] The signaling diagram 700 may be implemented by any suitable wireless communication device. In some aspects, the UE 115 may utilize one or more components such as Figure 3 The processor 302, memory 304, reporting module 308, transceiver 310, modem 312, and one or more antennas 316 are shown to perform any of the actions of the signaling diagram 700. In some aspects, the NG-RAN BS 605 can be similar to the BS 105 and / or BS 400 described previously. For example, the NG-RAN BS 705a and / or the NG-RAN BS 705b can utilize one or more components such as Figure 44. The E-UTRAN BS 725 is shown as a processor 402, a memory 404, a reporting module 408, a transceiver 410, a modem 412, and one or more antennas 414. In some aspects, the E-UTRAN BS 725 can be similar to the BS 105 and / or BS 400 described previously. For example, the E-UTRAN BS 725 can utilize one or more components such as Figure 4 The processor 402, memory 404, reporting module 408, transceiver 410, modem 412 and one or more antennas 414 are shown. As illustrated, the signaling diagram 700 includes several of the enumerated actions, but Figure 7 The various aspects of the invention may include additional actions before, after, and between the actions listed. In some aspects, one or more of the actions listed may be omitted, combined together, or performed in a different order.

[0138] It should be noted that any of actions 702 to 722 of the signaling diagram 700 may be performed for a UE (e.g., UE 115) in a connected mode or an idle mode. In this regard, the signaling diagram 700 may correspond to a handover procedure or a redirection procedure. Aspects of the signaling diagram 700 will first be described with reference to a handover procedure, and then aspects of the signaling diagram will be described with reference to a redirection procedure.

[0139] In some respects, Figure 6 The signaling diagram 600 shown may correspond to a dual connectivity scenario. For example, the NG-RAN BS 605 may be a primary node and the E-UTRAN BS 625b may be a secondary node. In this regard, the E-UTRAN BS 625b may communicate with the NG-RAN BS 605 and / or the E-UTRAN BS 625a. In some aspects, the signaling diagram 600 may correspond to a scenario in which the primary node is an NR cell and the secondary node is an LTE cell (NE-DC). In other aspects, the signaling diagram 600 may correspond to a scenario in which the primary node is an LTE cell and the secondary node is an NR cell (EN-DC). As will be described with reference to Figure 7 As described, in other aspects, a dual connectivity communication scenario may include UE 115 communicating with two NR cells.

[0140] In a dual connectivity scenario, the UE 115 may communicate with both the NG-RAN BS 605 as a primary node and the E-UTRAN BS 625b as a secondary node simultaneously. In such a scenario, the E-UTRAN BS 625b may not need to transmit an information request (e.g., at action 616). Instead, the UE 115 may be configured to automatically generate a report (e.g., at action 620) and send the report to the E-UTRAN BS 625b (e.g., at action 622). In such a scenario, processing time and computing resources may be reserved. In this scenario, the report generated at action 620 may be referred to as or include primary cell group (MCG) failure information and may include any type of fallback information described herein. The E-UTRAN BS 625b may then send a report including the MCG failure information and / or a fallback indication to the NG-RAN 605. The NG-RAN 605 may then perform any of the optimization processes described herein to improve communication quality and efficiency. In some aspects, the optimization process performed by the NG-RAN 605 may include selecting a different secondary node. In aspects where a different secondary node is selected, any of the reports described herein may include an indication of whether the secondary node has changed. Any of these reports may also include an indication of a previous secondary node cell ID (e.g., CGI) or a new secondary node cell ID.

[0141] At action 702, the NG-RAN BS 705a may send a mobility command to the UE 115. Action 702 may be similar to action 602 described previously. The NG-RAN BS 705a may be a 5G base station, including an independent or non-independent BS. The mobility command of action 702 may initiate an inter-system fallback, in which communication between the UE 115 and the NG-RAN BS 705a is terminated, and the UE 115 attempts to establish communication between the UE 115 and the E-UTRAN BS 725.

[0142] In some aspects, the mobility command of action 702 may include a mobility command message from the NR and may include various fallback indications, including fallback indications related to voice, emergency services, load balancing, or coverage issues. In some aspects, the mobility command may include various data, including the target RAT type and / or other data related to the target RAT, such as a message container.

[0143] At action 704, the UE 115 may identify the target BS. Action 704 may be similar to action 604 described previously. In some aspects, action 704 may include storing information from the mobility command 702. For example, at action 704, the UE 115 may store a fallback indication included in the mobility command 702, the fallback indication specifying whether the fallback involves voice fallback, emergency fallback, or fallback related to load balancing or coverage. In some aspects, the UE 115 may store an indication of the target RAT, the type of the target RAT, or a message or message container related to the target RAT. In some aspects, the information from the mobility command may be stored in a variable.

[0144] In some aspects, the UE 115 may identify the target RAT in any suitable manner. For example, the UE 115 may identify the target RAT based on the RAT specified by the NG-RAN BS 705a in the mobility command 702 at action 704. In some aspects, the UE 115 may select the target RAT based on the type of RAT specified by the NG-RAN BS 705a in the mobility command 702.

[0145] At act 706, the UE 115 sends a connection request to the E-UTRAN BS 725. In some aspects, the connection request may include a RACH request. Act 706 may be similar to act 606 described previously.

[0146] At action 708, UE 115 may determine that the connection between UE 115 and E-UTRAN BS 725 is unsuccessful. Action 708 may be similar to action 608 described previously. UE 115 may be configured to make this determination in any manner. For example, in response to not receiving a response signal from E-UTRAN BS 725, UE 115 may determine that the connection to E-UTRAN BS 725 has failed.

[0147] At act 710, UE 115 may store information related to the failure to establish a connection with E-UTRAN BS 725. Act 710 may be similar to act 610 described previously. The information may include any suitable data, including, for example, metrics related to channel quality between UE 115 and E-UTRAN BS 725, context information related to the connection request (such as the time of the request, the content of the request, or other specified parameters of the request), or any other information. In some aspects, the information stored by UE 115 at act 710 may include any of the information included in the mobility command of act 702. In some aspects, the information related to the failed connection may be stored in a variable (e.g., VarRLF-Report).

[0148] At action 712, UE 115 may search for an alternate E-UTRAN BS. For example, UE 115 may search for an alternate E-UTRAN BS because the connection request described with reference to action 706 was unsuccessful. Figure 7 In the example shown, the backup E-UTRAN BS may not be identified by UE 115. This failure to find a suitable alternative E-UTRAN BS may be due to coverage issues or any other suitable situation.

[0149] At act 714, in response to the failure to identify the backup E-UTRAN BS at act 712, the UE 115 may search for a NG-RAN BS instead of the backup E-UTRAN BS. In some aspects, the identified NG-RAN BS may be Figure 7 NG-RAN BS 705b is shown. In some aspects, the identified NG-RAN BS may be NG-RAN BS 705a that has initially established communication with UE 115 (e.g., as shown in action 702). In this regard, UE 115 may send a connection request to the NG-RAN BS identified at action 714. The connection request may include a RACH request or any other request.

[0150] At action 716, the NG-RAN BS 705b may send a request for information to the UE 115. Action 716 may be similar to action 616 described previously. In some aspects, in response to establishing a connection between the UE 115 and the NG-RAN BS 705b, the NG-RAN BS 705b may send a request for information to the UE 115. The request for information may specify any suitable information. For example, the request for information may include a request for information related to any previous failed connection attempts or information related to mobility commands from a previous BS. In some aspects, the request for information at action 716 may include a request for information related to failed connection requests to the NG-RAN BS 705b stored at action 710. In some aspects, the request for information may include a request for information from the mobility command 702. In other aspects, the request for information may include a request for information related to or resulting from any of actions 702 to 714.

[0151] At act 718, the UE 115 may access the requested information. Act 718 may be similar to previously described act 618. In some aspects, the UE 115 may access a memory of the UE 115 and retrieve the requested information.

[0152] At act 720, the UE 115 generates a report. Act 720 may be similar to act 620 described previously. In some aspects, the report may be based on or include any of the information requested by the NG-RAN BS 705b, including any of the information described with reference to act 716. In some aspects, the report generated at act 720 may include a radio link failure (RLF) report. The RLF report may include any suitable data. In some aspects, the RLF report may include reference to Figure 5 Any of the data or data types shown and described. It is noted that the RLF report may include a backoff indication. Figure 5 , the fallback indication may correspond to a voice fallback indication. In some aspects, the RLF report may additionally or alternatively include different types of fallback indications, such as an emergency fallback indication, a fallback indication due to load balancing, a fallback indication due to coverage issues, or any other type of fallback indication. In some aspects, the report generated by the UE 115 at action 720 may be referred to as an inter-RAT report or an inter-RAT RLF report.

[0153] In some aspects, the report generated at action 720 may include an indication of the NG-RAN BS 705a. The report may be stored and / or sent as an octet string or 8-bit bytes (e.g., with reference to action 722). In some aspects, a field of the report may indicate the primary cell (PCell) in which the RLF was detected and / or the source PCell of the failed handover. The report may include a field that includes the measurement results and is set to the value of the RLF report. In some aspects, the report may include the time elapsed since the last radio link failure or handover failure associated with the NG-RAN BS 705a, the E-UTRAN BS 725, and / or the NG-RAN BS 705b.

[0154] In some aspects, the report generated at action 720 may also include information related to the interruption time. For example, the report may include the handover interruption time. In this regard, the report may include a measure of the time between receipt of a successful RACH on the target cell (e.g., NG-RAN 705b) corresponding to a mobility command from the NR.

[0155] At action 722, the report generated at action 720 may be sent to the NG-RAN BS 705b. Action 722 may be similar to action 622 described previously. The report may be sent in any suitable manner or according to any wireless communication scheme or schedule. In some aspects, the NG-RAN 705b may be configured to, in response to receiving the report at action 722, send an indication to the UE 115 that the report was successfully received. In this regard, the UE 115 may be configured to receive the indication. Then, in response to receiving the indication that the report was successfully received by the NG-RAN 705b, the UE 115 may discard or otherwise delete the report from the memory of the UE 115. In some aspects, the UE 115 may determine that the report was successfully received in any other manner. In some aspects, it may be determined that the report was successfully sent and received, as confirmed by a lower layer.

[0156] As mentioned previously, the redirection process will now be described with reference to Figure 7 Aspects of signaling diagram 700.

[0157] At action 702, the NG-RAN BS 705a may send a mobility command to the UE 115. Action 702 may be similar to action 602 described previously. For the redirection process, the mobility command of action 702 may be an RRC release message. In some aspects, the UE 115 may be in an RRC connected mode and may transition to an RRC idle mode in response to receiving the RRC release message at action 702.

[0158] At action 704, UE 115 may identify the target BS. Action 704 may be similar to previously described action 604. Action 704 may include substantially similar steps with respect to the redirection process as previously described for the handover process.

[0159] At action 706, the UE 115 sends a connection request to the E-UTRAN BS 725. In some aspects, the connection request may include a RACH request. Action 706 may be similar to action 606 described previously. Action 706 may include steps substantially similar to the handover process described previously with respect to the redirection process.

[0160] At action 708, UE 115 may determine that the connection between UE 115 and E-UTRAN BS 725 is unsuccessful. Action 708 may be similar to previously described action 608. Action 708 may include substantially similar steps to the previously described handover process with respect to the redirection process.

[0161] At action 710, UE 115 may store information related to the failure to establish a connection with E-UTRAN BS 725. Action 710 may be similar to previously described action 610. Action 710 may include substantially similar steps to the previously described handover process with respect to the redirection process.

[0162] At action 712, UE 115 may search for a backup E-UTRAN BS. Action 712 may include substantially similar steps to the handover procedure described previously with respect to the redirection procedure.

[0163] At act 714, in response to identifying the backup E-UTRAN BS failure at act 712, UE 115 may search for a NG-RAN BS instead of the backup E-UTRAN BS. Act 714 may include steps substantially similar to the handover process described previously with respect to the redirection process.

[0164] At action 716, the NG-RAN BS 705b may send a request for information to the UE 115. Action 716 may be similar to the previously described action 616. Action 716 may include steps substantially similar to the previously described handover process with respect to the redirection process.

[0165] At action 718, the UE 115 may access the requested information. Action 718 may be similar to previously described action 618. Action 718 may include substantially similar steps with respect to the redirection process as previously described for the handover process.

[0166] At action 720, the UE 115 generates a report. Action 720 may be similar to action 620 described previously. Action 720 may be similar to action 620 described previously. For the redirection process, the report generated at action 720 may be referred to as a CEF report. The CEF report may include any of the data or information described above with reference to the report of action 720. In addition, the CEF report may include an indicator that the redirection failed due to fallback. The CEF report may also include an indicator specifying the fallback type (e.g., voice, emergency, load balancing, coverage issues, etc.) that triggered the redirection. In some aspects, the CEF report may include a cell global identifier (CGI) of the NG-RAN BS 705a. The CEF report may also include a reason for the redirection failure regarding action 706. In some aspects, if an RRC release is triggered for the purpose of redirecting to a cell due to a voice fallback indication, the report may include a metric corresponding to the time between the RRC release and a successful RACH on the target cell (e.g., NG-RAN BS 705a).

[0167] At action 722, the report generated at action 720 may be sent to the NG-RAN BS 705b. Action 722 may be similar to the previously described action 622. Action 722 may include steps substantially similar to the previously described handover process with respect to the redirection process.

[0168] In some aspects, the signaling diagram 700 may also include additional actions similar to actions 624 to 628 of the signaling diagram 600 described previously. In this regard, the NG-RAN 705b may send the report received from the UE 115 to the NG-RAN 705a. In some aspects, this may be implemented via various core network components such as the MME or AMF. In some aspects, the NG-RAN BS 705b may communicate directly with the NG-RAN BS 704a. As previously described with reference to Figure 6 As described, the NG-RAN BS 705a may use the information received within the report to optimize the communication or handover process in any manner previously described.

[0169] As reference Figure 6 As described in the signaling diagram 600, Figure 7 The signaling diagram 700 shown may correspond to a dual connectivity scenario. For example, the NG-RAN 705a may be a primary node and the NG-RAN 705b may be a secondary node. In this regard, the NG-RAN 705b may communicate with the NG-RAN BS 705a and / or the E-UTRAN BS 725. In this regard, the signaling diagram 700 may correspond to a communication scenario in which both the primary node and the secondary node are NR cells (e.g., NR-DC).

[0170] In a dual connectivity scenario, the UE 115 may communicate with both the NG-RAN BS 705a as a primary node and the NG-RAN 705b as a secondary node at the same time. In such a scenario, the NG-RAN BS 705b may not need to transmit an information request (e.g., at action 716). Instead, the UE 115 may be configured to automatically generate a report (e.g., at action 720) and send the report to the NG-RAN BS 705b (e.g., at action 722). In such a scenario, processing time and computing resources may be reserved. In this scenario, the report generated at action 720 may be referred to as or include master cell group (MCG) failure information and may include any type of fallback information described herein. Then, the NG-RAN BS 705b may send a report including the MCG failure information and / or a fallback indication to the NG-RAN 705a. The NG-RAN 705a may then perform any of the optimization processes described herein to improve communication quality and efficiency. In some aspects, the optimization process performed by the NG-RAN 705a may include selecting a different secondary node.

[0171] Figure 8 800 is a signaling diagram of communications between a UE 115, an NG-RAN BS 805, and an E-UTRAN BS 825 according to aspects of the present disclosure. The signaling diagram 800 may illustrate various communication scenarios in which different types of reports may be generated and sent from the UE 115 to the E-UTRAN BS 825 and then directly or indirectly to the NG-RAN BS 805. The signaling diagram 800 may be implemented by any suitable wireless communication device. In some aspects, the UE 115 may utilize one or more components, such as Figure 3 The processor 302, memory 304, reporting module 308, transceiver 310, modem 312, and one or more antennas 316 are shown to perform any of the actions in the signaling diagram 800. In some aspects, the NG-RAN BS 805 can be similar to the BS 105 and / or BS 400 described previously. For example, the NG-RAN BS 805 can utilize one or more components such as Figure 4 4. The E-UTRAN BS 825 is shown as a processor 402, a memory 404, a reporting module 408, a transceiver 410, a modem 412, and one or more antennas 414. In some aspects, the E-UTRAN BS 825 can be similar to the BS 105 and / or BS 400 described previously. For example, the E-UTRAN BS 825 can utilize one or more components such as Figure 4The processor 402, memory 404, reporting module 408, transceiver 410, modem 412 and one or more antennas 414 are shown. As illustrated, the signaling diagram 800 includes several of the enumerated actions, but Figure 8 The various aspects of the invention may include additional actions before, after, and between the actions listed. In some aspects, one or more of the actions listed may be omitted, combined together, or performed in a different order.

[0172] It should be noted that any of actions 802 through 816 of signaling diagram 800 may be performed for a UE in connected mode or idle mode (eg, UE 115). In this regard, signaling diagram 800 may correspond to a handover procedure or a redirection procedure.

[0173] At action 802, the NG-RAN BS 805 may send a mobility command to the UE 115. The NG-RAN BS 805 may be a 5G base station, including an independent or non-independent BS. The mobility command described with reference to action 802 may be substantially similar to that described with reference to Figure 2 The described mobility command 210 and / or reference Figure 8 Described action 802. The mobility command of action 802 may initiate an inter-system fallback, wherein communications between the UE 115 and the NG-RAN BS 805 are terminated and communications between the UE 115 and the E-UTRAN BS 825 are established.

[0174] In some aspects, the mobility command of action 802 may include a mobility command message from the NR and may include various fallback indications, including fallback indications related to voice, emergency services, load balancing, or coverage issues. In some aspects, the mobility command may include various data, including the target RAT type and / or other data related to the target RAT, such as a message container.

[0175] At action 804, UE 115 may identify the target BS. In some aspects, action 804 may additionally include storing information from the mobility command 802 in a memory of UE 115. For example, at action 804, UE 115 may store a fallback indication included in the mobility command 802, the fallback indication specifying whether the fallback involves voice fallback, emergency fallback, or fallback related to load balancing or coverage. In some aspects, UE 115 may store data, such as an indication of the target RAT, the type of the target RAT, or a message or message container related to the target RAT. In some aspects, the information from the mobility command may be stored in a variable. UE 115 may identify the target RAT in any suitable manner. For example, UE 115 may identify the target RAT based on the RAT specified by BS 805 in the mobility command 802 at action 804. In some aspects, UE 115 may select the target RAT based on the type of RAT specified by BS 805 in the mobility command 802.

[0176] At act 806, the UE 115 sends a connection request to the E-UTRAN BS 825. In some aspects, the connection request may include a RACH request.

[0177] At action 808, UE 115 may determine that a connection between UE 115 and E-UTRAN BS 825 has been successfully established. In some aspects, E-UTRAN BS 825 may send an indication that a connection between UE 115 and E-UTRAN BS 825 was successfully established. In some aspects, UE 115 may determine that a connection between UE 115 and E-UTRAN BS 825 was successfully established in any other manner.

[0178] At action 810, UE 115 generates a report. The report generated at action 810 may be a report of any suitable type and may include any suitable information. For example, the report may include metrics related to the channel quality between UE 115 and E-UTRAN BS 825 and / or NG-RAN BS 805, context information related to the connection request or completed connection between UE 115 and E-UTRAN BS 825 (such as the time of the requested or completed connection, the content of the request, or an indication of the completed connection), or other specified parameters or any other information. In some aspects, the report generated at action 810 may include any information included in the information of the mobility command of action 802 described previously. In some aspects, the report may additionally include a fallback indication. For example, the report of action 810 may include a fallback indication specifying the reason for the fallback process. In this regard, the report generated at action 810 may include a voice fallback indication, an emergency fallback indication, a load balancing fallback indication, and / or a coverage fallback indication.

[0179] In some aspects, the report generated at action 810 including the fallback indication may be any suitable type of report. For example, if the successful RACH between the UE 115 and the E-UTRAN BS 825 is due to an inter-system handover triggered by EPS fallback or a successful redirection from an NR with voice fallback, the report of action 810 may be a RACH report. In some aspects, if the previous successful handover was due to an inter-system handover triggered by EPS fallback, the report of action 810 may be a successful handover report. In some aspects, if the mobility is due to an inter-system handover triggered by EPS fallback, the report of action 810 may be a mobility history report. In this regard, the report generated at action 810 may be a RACH report, a successful handover report, or a mobility history report, each of which may include a fallback indication of any suitable type, including any of the types listed previously. In some aspects, additionally or alternatively, the report generated at act 810 may be an RLF report (e.g., in aspects where UE 115 is in RRC connected mode) or a CEF report (e.g., in aspects where UE 115 is in RRC idle mode). In some aspects, the report generated at act 810 may include a successful handover report (SHR).

[0180] In aspects where the reporting at action 810 includes an RLF report, an SHR, or a CEF report, the UE 115 may prioritize reporting radio measurement results of neighboring E-UTRA cells within the report to the E-UTRAN BS 825 .

[0181] At action 812, the E-UTRAN BS 825 may send a request for information to the UE 115. In some aspects, in response to establishing a connection between the UE 115 and the E-UTRAN BS 825, the E-UTRAN BS 825 may send a request for information to the UE 115. The request for information may specify any suitable information. For example, the request for information may include a request for the report generated at action 810. In some aspects, the request for information may include information related to a previous failed connection attempt or information related to a mobility command from a previous BS. In some aspects, the request for information may include a request for information from the mobility command 802.

[0182] At act 814, UE 115 may access the report generated at act 810. In some aspects, UE 115 may access a memory of UE 115 and retrieve the requested report or information.

[0183] At action 816, the report generated at action 810 may be sent to the E-UTRAN BS 825. The report may be sent in any suitable manner or according to any wireless communication scheme or schedule. In some aspects, the E-UTRAN BS 825 may be configured to, in response to receiving the report at action 816, send an indication to the UE 115 that the report was successfully received. In this regard, the UE 115 may be configured to receive the indication. Then, in response to receiving the indication that the report was successfully received by the E-UTRAN BS 825, the UE 115 may discard or otherwise delete the report from the memory of the UE 115. In some aspects, the UE 115 may determine that the report was successfully received in any other manner. In some aspects, it may be determined that the report was successfully sent and received, as confirmed by a lower layer.

[0184] In some aspects, the signaling diagram 800 may also include additional actions similar to actions 624 to 628 of the signaling diagram 600 described previously. In this regard, the E-UTRAN BS 825 may be configured to send the eNB configuration to the MME in communication with the E-UTRAN BS 825. The MME may then send the N26 message to the AMF in communication with the NG-RAN BS 805. The AMF may then send the report generated at action 810 to the NG-RAN BS 805, or select information within the report of action 810. As previously described with reference to Figure 6 As described, the NG-RAN BS 805 may use the information received from the AMF to optimize the communication or handover process in any manner previously described.

[0185] Fig. 9900 according to some aspects of the present disclosure. Aspects of the method 900 may be performed by a computing device (e.g., a processor, processing circuitry, and / or other suitable components) of a wireless communication device or other suitable means for performing these aspects. For example, a wireless communication device (such as UE 300) may utilize one or more components (such as processor 302, memory 304, reporting module 308, transceiver 310, modem 312, and / or antenna 316) to perform aspects of the method 900. The method 900 may be implemented in accordance with aspects of the present disclosure. Figures 5 to 8 The method 900 includes several aspects enumerated, but the method 900 may include additional aspects before, after, and / or between the aspects enumerated. In some aspects, one or more of these enumerated aspects may be omitted or performed in a different order.

[0186] At block 910, method 900 includes receiving a first signal from a first NG-RAN BS, the first signal including a fallback indication. In some aspects, the first signal may be a mobility command. In some aspects, the UE may disconnect the wireless communication with the first NG-RAN BS in response to receiving the first signal. In some aspects, the first signal may be an RRC release signal or any other suitable command signal. In some aspects, the first signal may include a fallback indication. The fallback indication may specify a fallback type that may correspond to the mobility command of the first signal. In some aspects, the fallback indication may be included in the mobility command. In other aspects, the UE may generate and / or otherwise determine the fallback indication.

[0187] At block 920, method 900 includes sending a second signal to the first E-UTRAN BS, the second signal including a connection request. In some aspects, the UE may perform a search for additional cells or BSs within range of the UE. As a result of the search, the UE may identify the BS. In some aspects, the BS may be an E-UTRAN BS. The second signal sent by the UE to the first E-UTRAN BS may include a connection request, such as a RACH request. In some aspects, as previously described with reference to Figure 6 to Figure 7 As described, the UE may identify the target BS based on an indication of the target BS or the type of BS received in the mobility command.

[0188] At block 930, method 900 includes determining that the connection request failed. In some aspects, in response to not receiving a response from the first E-UTRAN BS, the UE may determine that the connection attempt with the first E-UTRAN BS may have failed. In some aspects, the UE may specify a time limit within which the UE must receive a response in order to verify that the connection has been established. In some aspects, the UE may additionally store information related to the failed connection request.

[0189] At block 940, method 900 includes generating a report corresponding to the failed connection attempt. In some aspects, the report generated at block 940 may include any of the information stored by the UE at block 930. For example, the report may include reference to Figure 6 In some aspects, the report may additionally include information received by the UE from the first NG-RAN. For example, the reported information may include a first signal received by the UE. In some aspects, the UE may additionally perform a second search for cells or BSs within the range of the UE. When performing this action, the UE may identify a backup BS. In some aspects, the backup BS may be a second E-UTRAN BS or may be a second NG-RAN BS. After identifying the backup BS, the UE may send a connection request to the backup BS. The connection request may be similar to the connection request described with reference to box 920.

[0190] At block 950, method 900 includes sending a third signal to the second wireless communication device, the third signal including the report. In some aspects, the UE may send the third signal in response to receiving an information request from the second wireless communication device. In some aspects, the third signal may include the report of block 940 and any other suitable information. In response to receiving the report, the second wireless communication device may pass information from the report to the first NG-RAN described with reference to block 910. This may be implemented in any suitable manner. For example, the second wireless communication device may pass various aspects of the report to a component of a core network that communicates with the second wireless communication device. In some aspects, the second wireless communication device may pass various aspects of the report directly to the NG-RAN BS of block 910.

[0191] Fig.10 1 is a flow chart of a wireless communication method 1000 according to some aspects of the present disclosure. Various aspects of the method 1000 may be performed by a computing device (e.g., a processor, processing circuitry, and / or other suitable components) of a wireless communication device or other suitable means for performing such aspects. For example, a wireless communication device (such as BS 400) may utilize one or more components (such as processor 402, memory 404, reporting module 408, transceiver 410, modem 412, and / or antenna 416) to perform various aspects of the method 1000. The method 1000 may be implemented in accordance with aspects of the present disclosure. Figures 5 to 8 As shown, method 1000 includes several enumerated aspects, but method 1000 may include additional aspects before, after, and / or between the enumerated aspects. In some aspects, one or more of these enumerated aspects may be omitted or performed in a different order.

[0192] At block 1010, method 1000 includes receiving a first signal from a UE, the first signal including a connection request. In some aspects, as part of a fallback process, the UE may send a connection request in response to having been disconnected from the BS. In addition, the UE may have previously attempted to connect to the E-UTRAN BS. However, the connection attempt may have failed. In this regard, the connection request received at block 1010 may be a request from the UE to connect to a backup BS to replace an initially identified E-UTRAN BS with which a connection was not established.

[0193] At block 1020, method 1000 includes sending a second signal to the UE, the second signal including a request for information. In some aspects, block 1020 may include, in response to the connection being established between the UE and the standby E-UTRAN BS identified at block 1010, sending a request for information to the UE. The request for information may specify any suitable information. For example, the request for information may include a request for information related to any previous failed connection attempts or information related to mobility commands from a previous BS. In some aspects, the request for information may include a request for information from a previous mobility command received by the UE.

[0194] At block 1030, method 1000 includes receiving a third signal from the UE, the third signal including a report including a fallback indication. In some aspects, the report may be based on or include any of the information requested at block 1020. In some aspects, the received report may include a radio link failure (RLF) report. The RLF report may include any suitable data. In some aspects, the RLF report may include a reference to Figure 5 Any of the data or data types shown and described. It is noted that the RLF report may include a backoff indication. Figure 5 , the fallback indication may correspond to a voice fallback indication. In some aspects, the RLF report may additionally or alternatively include different types of fallback indications, such as an emergency fallback indication, a fallback indication due to load balancing, a fallback indication due to coverage issues, or any other type of fallback indication.

[0195] In some aspects, the report generated at act 620 may include an indication of the NG-RAN BS that was previously in communication with the BS. In some aspects, a field of the report may indicate the PCell in which the RLF was detected and / or the source PCell of the failed handover. The report may include a field that includes the measurement results and is set to the value of the RLF report. In some aspects, the report may include the time elapsed since the last radio link failure or handover failure.

[0196] At block 1040, method 1000 includes sending a fallback indication to a BS previously communicating with the UE. In this regard, a report received from the UE in a previous communication with the UE may be sent to the NG-RAN, e.g., the NG-RAN initiating the fallback procedure. In some aspects, this may be implemented via various core network components such as an MME or AMF. The NG-RAN BS may use the information received within the report to optimize the communication or handover process in any manner previously described.

[0197] Fig.11 A diagram illustrating an example disaggregated base station 1100 architecture is shown. The disaggregated base station 1100 architecture may include one or more central units (CUs) 1110 that may communicate directly with a core network 1120 via a backhaul link, or indirectly with the core network 1120 through one or more disaggregated base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 1125 via an E2 link, or a non-real-time (non-RT) RIC 1115 associated with a service management and orchestration (SMO) framework 1105, or both. The CU 1110 may communicate with one or more distributed units (DUs) 1130 via respective midhaul links, such as an F1 interface. The DU 1130 may communicate with one or more radio units (RUs) 1140 via respective fronthaul links. The RU 1140 may communicate with respective UEs 120 via one or more radio frequency (RF) access links. In some implementations, a UE 120 may be served simultaneously by multiple RUs 1140. Aspects of the disclosure described as occurring at or controlled by the BS may occur at any one or more of these different units.

[0198] Each of these units (i.e., CU 1110, DU 1130, RU 1140, and near-RT RIC 1125, non-RT RIC 1115, and SMO framework 1105) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of these units or an associated processor or controller that provides instructions to the communication interface of these units may be configured to communicate with one or more of the other units via a transmission medium. For example, these units may include a wired interface configured to receive or send signals to one or more of the other units via a wired transmission medium. Additionally, these units may include a wireless interface that may include a receiver, a transmitter, or a transceiver (such as a radio frequency (RF) transceiver) that is configured to receive or send signals, or both, to one or more of the other units via a wireless transmission medium.

[0199] In some aspects, CU 1110 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface configured to communicate signals with other control functions hosted by CU 1110. CU1110 may be configured to handle user plane functionality (i.e., central unit-user plane (CU-UP)), control plane functionality (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 1110 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 1110 may be implemented to communicate with DU 1130 for network control and signaling.

[0200] DU 1130 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 1140. In some aspects, DU 1130 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) depending at least in part on a functional split, such as that defined by the Third Generation Partnership Project (3GPP). In some aspects, DU 1130 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 1130 or with control functions hosted by CU 1110.

[0201] The lower layer functionality may be implemented by one or more RUs 1140. In some deployments, the RU 1140 controlled by the DU 1130 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing Fast Fourier Transform (FFT), Inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on functional splitting (such as lower layer functional splitting). In such an architecture, the RU 1140 may be implemented to handle over-the-air (OTA) communications with one or more UEs 120. In some implementations, real-time and non-real-time aspects of communicating with the control plane and user plane of the RU 1140 may be controlled by the corresponding DU 1130. In some scenarios, this configuration may enable the DU 1130 and CU 1110 to be implemented in a cloud-based RAN architecture (such as a vRAN architecture).

[0202] The SMO framework 1105 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 1105 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 1105 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 1190) to perform network element lifecycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 1110, DU 1130, RU 1140, and near-RT RIC 1125. In some specific implementations, the SMO framework 1105 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 1111) via the O1 interface. Additionally, in some implementations, the SMO framework 1105 can communicate directly with one or more RUs 1140 via the O1 interface. The SMO framework 1105 can also include a non-RT RIC 1115 configured to support the functionality of the SMO framework 1105.

[0203] The non-RT RIC 1115 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 1125. The non-RT RIC 1115 may be coupled to or in communication with the near-RT RIC 1125 (such as via an A1 interface). The near-RT RIC 1125 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 1110, one or more DUs 1130, or both, and the O-eNB with the near-RTRIC 1125.

[0204] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 1125, the non-RT RIC 1115 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 1125 and may be received from a non-network data source or from a network function at the SMO framework 1105 or the non-RT RIC 1115. In some examples, the non-RT RIC 1115 or the near-RT RIC 1125 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 1115 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 1105 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0205] Fig.12 A diagram of a system 1200 including a device 1405 supporting RU sharing techniques in wireless communications according to various aspects of the present disclosure is shown. The device 1405 may communicate with one or more RUs 1255. The device 1405 may include components for two-way voice and data communications, including components for sending and receiving communications, such as a communication manager 1220, a network communication manager 1210, a memory 1230, a code 1235, a processor 1240, and a RU communication manager 1245. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., a bus 1250). One or more of the components of the system 1200 may perform as described herein with reference to Figures 5 to 10 The functions described are, for example, described as functions performed by a base station or a network element.

[0206] The network communications manager 1210 may manage communications with the core network 1260 (eg, via one or more wired backhaul links). For example, the network communications manager 1210 may manage the delivery of data communications for client devices, such as one or more UEs 115.

[0207] Memory 1230 may include RAM and ROM. Memory 1230 may store computer-readable, computer-executable code 1235 including instructions that, when executed by processor 1240, cause device 1405 to perform various functions described herein. Code 1235 may be stored in a non-transitory computer-readable medium, such as system memory or another type of memory. In some cases, code 1235 may not be directly executable by processor 1240, but may (e.g., when compiled and executed) cause a computer to perform the functions described herein. In some cases, in addition to this, memory 1230 may also include BIOS, which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0208] Processor 1240 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor 1240 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into processor 1240. Processor 1240 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1230) to enable device 1405 to perform various functions (e.g., functions or tasks supporting RU sharing technology in wireless communications). For example, device 1405 or a component of device 1405 may include processor 1240 and memory 1230 coupled to processor 1240, and processor 1240 and memory 1230 are configured to perform the various functions described herein.

[0209] RU communication manager 1245 may manage communications with RU 1255 and may include a controller or scheduler for controlling communications with UE 115 in coordination with RU 1255. For example, RU communication manager 1245 may coordinate scheduling of transmissions to UE 115. In some examples, RU communication manager 1245 may provide an F1 interface within a wireless communication network technology to provide communications with RU 1255.

[0210] According to examples as disclosed herein, the communication manager 1220 may support wireless communications at a network node. For example, the communication manager 1220 may be configured to or otherwise support components for sending a request for a radio resource configuration to a first RU during a first time period. The communication manager 1220 may be configured to or otherwise support components for sending an interference query associated with the radio resource configuration to a second RU during a first time period. The communication manager 1220 may be configured to or otherwise support components for receiving a response to the interference query from the second RU. The communication manager 1220 may be configured to or otherwise support components for sending a payload to the first RU for transmission during the first time period based on the response to the interference query.

[0211] By including or configuring a communication manager 1220 according to the examples described herein, the device 1405 may support technology for RU sharing, wherein DUs of different MNOs may access wireless resources of other MNOs, which may increase the efficiency of resource utilization while providing competition and innovation among different MNOs, which may increase the reliability of wireless communications, reduce latency, and enhance user experience.

[0212] In some examples, the communication manager 1220 may be configured to perform various operations (e.g., receive, monitor, send) using or otherwise cooperating with other components. Although the communication manager 1220 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 1220 may be supported or performed by the processor 1240, the memory 1230, the code 1235, or any combination thereof. For example, the code 1235 may include instructions that can be executed by the processor 1240 to cause the device 1405 to perform various aspects of the RU sharing technology in wireless communications as described herein, or the processor 1240 and the memory 1230 may be otherwise configured to perform or support such operations.

[0213] Other aspects of the present disclosure include the following:

[0214] Aspect 1 includes a method of wireless communication, the method comprising: receiving, by a first wireless communication device, a first signal from a first next generation radio access network (NG-RAN) base station, the first signal including a fallback indication; in response to receiving the first signal, sending, by the first wireless communication device, a second signal to a first evolved universal mobile telecommunications system terrestrial radio access network (E-UTRAN) base station, the second signal including a connection request; and sending, by the first wireless communication device to a second wireless communication device, a third signal including a report in response to a connection failure with the first E-UTRAN base station.

[0215] Aspect 2 includes a method according to aspect 1, wherein the report includes a flag, the flag being configured to be set to a true value in response to the failure to establish the connection with the first E-UTRAN base station being due to voice fallback, and to be set to a false value in response to the failure to establish the connection with the first E-UTRAN base station being not due to voice fallback.

[0216] Aspect 3 includes a method according to any one of Aspects 1 to 2, wherein the report includes: a first field, the first field corresponding to a handover report type, wherein in response to the fallback indication indicating voice fallback, the handover report type of the report is set to EPS fallback failure; and a second field, the second field corresponding to the fallback indication.

[0217] Aspect 4 includes the method according to any one of aspects 1 to 3, wherein the second wireless communication device is a second E-UTRAN base station.

[0218] Aspect 5 includes a method according to any one of aspects 1 to 4, wherein the second wireless communication device is a second NG-RAN base station.

[0219] Aspect 6 includes a method according to any one of aspects 1 to 5, the method further comprising: in response to failure to establish the connection with the first E-UTRAN base station, searching for the second wireless communication device, wherein the report includes an indication that the search did not identify a second E-UTRAN base station.

[0220] Aspect 7 includes a method according to any one of aspects 1 to 6, wherein the report includes a cell global identity (CGI) of the first NG-RAN base station or the first E-UTRAN base station.

[0221] Aspect 8 includes the method of any one of aspects 1 to 7, wherein the report includes an indication of the time that has elapsed since a previous radio link failure.

[0222] Aspect 9 includes the method according to any one of aspects 1 to 8, further comprising: discarding the report after sending the third signal.

[0223] Aspect 10 includes the method of any one of aspects 1 to 9, wherein: the first wireless communication device is in an active state and the report is a radio link failure (RLF) report.

[0224] Aspect 11 includes the method of any one of aspects 1 to 10, wherein: the wireless communication device is in an idle state and the report is a connection establishment (CEF) report.

[0225] Aspect 12 includes a method according to any one of aspects 1 to 11, wherein a random access channel (RACH) report comprises the report in response to a successful RACH following a handover or redirection from the first NG-RAN base station.

[0226] Aspect 13 includes the method of any one of aspects 1 to 12, further comprising sending, by the first wireless communication device, an indication of a handover interruption time.

[0227] Aspect 14 includes the method of any one of aspects 1 to 13, the method further comprising sending, by the first wireless communication device, an indication of a time between an RRC release and a successful RACH corresponding to the second wireless communication device.

[0228] Aspect 15 includes the method according to any one of aspects 1 to 14, wherein the report includes a successful handover report.

[0229] Aspect 16 includes the method according to any one of aspects 1 to 15, wherein the report includes a mobility history report.

[0230] Aspect 17 includes the method of any one of aspects 1 to 16, wherein the report is selected and generated based on prioritizing neighboring cells by the first wireless communication device.

[0231] Aspect 18 includes the method according to any one of aspects 1 to 17, wherein the fallback indication corresponds to speech fallback.

[0232] Aspect 19 includes the method according to any one of aspects 1 to 18, wherein the fallback indication corresponds to an emergency fallback.

[0233] Aspect 20 includes a method of wireless communication, the method comprising: receiving a first signal from a user equipment (UE) by a first wireless communication device, the first signal including a connection request; sending a second signal to the UE by the first wireless communication device, the second signal including an information request; receiving a third signal from the UE by the first wireless communication device, the third signal including a report generated in response to a failure to establish a connection between the UE and a second wireless communication device, the report including a fallback indication.

[0234] Aspect 21 includes a method according to aspect 20, wherein the report includes a flag, which is configured to be set to a true value in response to the failure to establish the connection between the UE and the second wireless communication device being due to voice fallback, and to be set to a false value in response to the failure to establish the connection between the UE and the second wireless communication device not being due to voice fallback.

[0235] Aspect 22 includes a method according to any one of Aspects 20 to 21, wherein the report further includes: a first field, the first field corresponding to a handover report type, wherein in response to the fallback indication indicating voice fallback, the handover report type of the report is set to EPS fallback failure; and a second field, the second field corresponding to the fallback indication.

[0236] Aspect 23 includes a method according to any one of aspects 20 to 22, wherein the first wireless communication device is an E-UTRAN base station.

[0237] Aspect 24 includes a method according to any one of aspects 20 to 23, wherein the first wireless communication device is a NG-RAN base station.

[0238] Aspect 25 includes a method according to any one of aspects 20 to 24, wherein: the second wireless communication device is a first E-UTRAN base station; the first signal is received in response to the failure to establish the connection between the UE and the second wireless communication device; and the report includes an indication that the search did not identify a second E-UTRAN base station.

[0239] Aspect 26 includes a method according to any one of aspects 20 to 25, wherein the report includes a cell global identity (CGI) of an NG-RAN base station or the second wireless communication device that previously communicated with the UE.

[0240] Aspect 27 includes the method of any one of aspects 20 to 26, wherein the report includes an indication of the time elapsed since a previous radio link failure.

[0241] Aspect 28 includes a method according to any one of aspects 20 to 27, wherein: the UE is in an active state and the report is a radio link failure (RLF) report.

[0242] Aspect 29 includes a method according to any one of aspects 20 to 28, wherein: the UE is in an idle state and the report is a connection establishment (CEF) report.

[0243] Aspect 30 includes the method of any of aspects 20 to 29, wherein a random access channel (RACH) report comprises the report in response to a successful RACH on the first wireless communications device after a handover or redirection.

[0244] Aspect 31 includes a method according to any one of aspects 20 to 30, the method further comprising receiving, by the first wireless communications device, an indication of a time between an RRC release and the successful RACH.

[0245] Aspect 32 includes the method of any one of aspects 20 to 31, further comprising receiving, by the first wireless communication device, an indication of a handover interruption time.

[0246] Aspect 33 includes a method according to any one of aspects 20 to 32, wherein the report includes a successful handover report.

[0247] Aspect 34 includes a method according to any one of aspects 20 to 33, wherein the report includes a mobility history report.

[0248] Aspect 35 includes a method according to any one of aspects 20 to 34, wherein the report is selected and generated based on the UE prioritizing neighboring cells.

[0249] Aspect 36 includes a method according to any one of aspects 20 to 35, wherein the fallback indication corresponds to speech fallback.

[0250] Aspect 37 includes a method according to any one of aspects 20 to 36, wherein the fallback indication corresponds to an emergency fallback.

[0251] Aspect 38 includes a method according to any one of aspects 20 to 37, the method also comprising sending, by the first wireless communication device, the report to one or more components of a core network for delivery to a NG-RAN BS.

[0252] Aspect 39 includes a method according to any one of aspects 20 to 38, the method further comprising sending the report by the first wireless communication device to a NG-RAN BS for communication optimization.

[0253] Aspect 40 includes a wireless communication device, comprising: a transceiver; and a processor coupled to the transceiver, wherein the wireless communication device is configured to: receive a first signal from a first next generation radio access network (NG-RAN) base station, the first signal comprising a fallback indication; in response to receiving the first signal, send a second signal to a first evolved universal mobile telecommunications system terrestrial radio access network (E-UTRAN) base station, the second signal comprising a connection request; and send a third signal to a second wireless communication device, the third signal comprising a report in response to a connection failure with the first E-UTRAN base station.

[0254] Aspect 41 includes a wireless communication device according to aspect 40, wherein the report includes a flag, the flag being configured to be set to a true value in response to the failure to establish the connection with the first E-UTRAN base station being due to voice fallback, and to be set to a false value in response to the failure to establish the connection with the first E-UTRAN base station not being due to voice fallback.

[0255] Aspect 42 includes a wireless communication device according to any one of Aspects 40 to 41, wherein the report includes: a first field, the first field corresponding to a handover report type, wherein in response to the fallback indication indicating voice fallback, the handover report type of the report is set to EPS fallback failure; and a second field, the second field corresponding to the fallback indication.

[0256] Aspect 43 includes the wireless communication device of any one of aspects 40 to 42, wherein the second wireless communication device is a second E-UTRAN base station.

[0257] Aspect 44 includes a wireless communication device according to any one of aspects 40 to 43, wherein the second wireless communication device is a second NG-RAN base station.

[0258] Aspect 45 includes a wireless communication device according to any one of aspects 40 to 44, the wireless communication device being further configured to: in response to failure to establish the connection with the first E-UTRAN base station, search for the second wireless communication device, wherein the report includes an indication that the search did not identify a second E-UTRAN base station.

[0259] Aspect 46 includes a wireless communications apparatus according to any one of aspects 40 to 45, wherein the report includes a cell global identity (CGI) of the first NG-RAN base station or the first E-UTRAN base station.

[0260] Aspect 47 includes a wireless communications apparatus according to any one of aspects 40 to 46, wherein the report includes an indication of a time that has elapsed since a previous radio link failure.

[0261] Aspect 48 includes a wireless communication device according to any one of aspects 40 to 47, the wireless communication device being further configured to discard the report after sending the third signal.

[0262] Aspect 49 includes a wireless communication device according to any one of aspects 40 to 48, wherein: the wireless communication device is in an active state and the report is a radio link failure (RLF) report.

[0263] Aspect 50 includes a wireless communication device according to any one of aspects 40 to 49, wherein: the wireless communication device is in an idle state and the report is a connection establishment (CEF) report.

[0264] Aspect 51 includes a wireless communications apparatus according to any one of aspects 40 to 50, wherein a random access channel (RACH) report comprises the report in response to a successful RACH following a handover or redirection from the first NG-RAN base station.

[0265] Aspect 52 includes a wireless communication device according to any one of aspects 40 to 51, the wireless communication device being further configured to send an indication of a time between an RRC release and the successful RACH corresponding to the second wireless communication device.

[0266] Aspect 53 includes the wireless communication device according to any one of aspects 40 to 52, the wireless communication device being further configured to send an indication of a handover interruption time.

[0267] Aspect 54 includes a wireless communications apparatus as described in any one of aspects 40 to 53, wherein the report comprises a successful handover report.

[0268] Aspect 55 includes a wireless communications apparatus according to any one of aspects 40 to 54, wherein the report comprises a mobility history report.

[0269] Aspect 56 includes a wireless communications device according to any one of aspects 40 to 55, the wireless communications device being further configured to prioritize neighboring cells, and wherein the report is selected and generated based on the prioritization.

[0270] Aspect 57 includes a wireless communications apparatus as set forth in any one of aspects 40 to 56, wherein the fallback indication corresponds to voice fallback.

[0271] Aspect 58 includes a wireless communications apparatus as set forth in any one of aspects 40 to 57, wherein the fallback indication corresponds to an emergency fallback.

[0272] Aspect 59 includes a wireless communication device, comprising: a transceiver; and a processor, the processor being coupled to the transceiver, wherein the wireless communication device is configured to: receive a first signal from a user equipment (UE), the first signal comprising a connection request; send a second signal to the UE, the second signal comprising an information request; receive a third signal from the UE, the third signal comprising a report generated in response to a failure to establish a connection between the UE and a second wireless communication device, the report comprising a fallback indication.

[0273] Aspect 60 includes a wireless communication device according to aspect 59, wherein the report includes a flag, which is configured to be set to a true value in response to the failure to establish the connection between the UE and the second wireless communication device being due to voice fallback, and to be set to a false value in response to the failure to establish the connection between the UE and the second wireless communication device not being due to voice fallback.

[0274] Aspect 61 includes a wireless communication device according to any one of Aspects 59 to 60, wherein the report also includes: a first field, the first field corresponding to a handover report type, wherein in response to the fallback indication indicating voice fallback, the handover report type of the report is set to EPS fallback failure; and a second field, the second field corresponding to the fallback indication.

[0275] Aspect 62 includes a wireless communication device according to any one of aspects 59 to 61, wherein the wireless communication device is an E-UTRAN base station.

[0276] Aspect 63 includes a wireless communication device according to any one of aspects 59 to 62, wherein the wireless communication device is a NG-RAN base station.

[0277] Aspect 64 includes a wireless communication device according to any one of aspects 59 to 63, wherein: the second wireless communication device is a first E-UTRAN base station; the wireless communication device is configured to receive the first signal in response to the failure to establish the connection between the UE and the second wireless communication device; and the report includes an indication that the search did not identify a second E-UTRAN base station.

[0278] Aspect 65 includes a wireless communications device according to any one of aspects 59 to 64, wherein the report includes a cell global identity (CGI) of an NG-RAN base station or a second wireless communications device that previously communicated with the UE.

[0279] Aspect 66 includes a wireless communications apparatus as described in any of aspects 59 to 65, wherein the report includes an indication of a time that has elapsed since a previous radio link failure.

[0280] Aspect 67 includes a wireless communications apparatus as described in any one of aspects 59 to 66, wherein: the UE is in an active state and the report is a radio link failure (RLF) report.

[0281] Aspect 68 includes a wireless communications apparatus according to any one of aspects 59 to 67, wherein: the UE is in an idle state and the report is a connection establishment (CEF) report.

[0282] Aspect 69 includes a wireless communications device as set forth in any one of aspects 59 to 68, wherein a random access channel (RACH) report comprises the report in response to a successful RACH on the first wireless communications device following a handover or redirection.

[0283] Aspect 70 includes a wireless communications device according to any one of aspects 59 to 69, the wireless communications device being further configured to receive an indication of a time between an RRC release and the successful RACH.

[0284] Aspect 71 includes the wireless communication device of any of aspects 59 to 70, the wireless communication device being further configured to receive an indication of a handover interruption time.

[0285] Aspect 72 includes a wireless communications apparatus as described in any one of aspects 59 to 71, wherein the report comprises a successful handover report.

[0286] Aspect 73 includes a wireless communications apparatus according to any one of aspects 59 to 72, wherein the report comprises a mobility history report.

[0287] Aspect 74 includes a wireless communications apparatus according to any one of aspects 59 to 73, wherein the report is selected and generated based on the UE prioritizing neighboring cells.

[0288] Aspect 75 includes a wireless communication apparatus as set forth in any one of aspects 59 to 74, wherein the fallback indication corresponds to voice fallback.

[0289] Aspect 76 includes a wireless communications apparatus as set forth in any one of aspects 59 to 75, wherein the fallback indication corresponds to an emergency fallback.

[0290] Aspect 77 includes a wireless communication device according to any one of aspects 59 to 76, the wireless communication device being further configured to send the report to one or more components of a core network for delivery to a NG-RAN BS.

[0291] Aspect 78 includes a wireless communication device according to any one of aspects 59 to 77, the wireless communication device being further configured to send the report to a NG-RAN BS for communication optimization.

[0292] 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 mentioned throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0293] The various illustrative blocks and modules described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, DSP, ASIC, 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. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The 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, a combination of one or more microprocessors and a DSP core, or any other such configuration).

[0294] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium, or sent via a computer-readable medium. Other examples and specific implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software, hardware, firmware, hard wiring, or any combination thereof executed by a processor. The features that implement the functions may also be physically located at different locations, including being distributed so that the parts of the functions are implemented at different physical locations. In addition, as used herein (including in the claims), as used in an item enumeration (e.g., followed by an item enumeration such as "at least one of" or "one or more of"), "or" indicates an inclusive enumeration, such that, for example, an enumeration of [at least one of A, B, or C] means: A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0295] As those skilled in the art will understand by now and depending on the specific application at hand, many modifications, substitutions and changes may be made to the materials, devices, configurations and methods of use of the apparatus of the present disclosure without departing from the spirit and scope of the present disclosure. In view of this, the scope of the present disclosure should not be limited to the specific embodiments illustrated and described herein (as they are only some examples of the present disclosure), but should be fully equivalent to the appended claims and their functional equivalents.

Claims

1. A method for wireless communication, the method comprising: receiving, by a first wireless communication device, a first signal from a first next generation radio access network (NG-RAN) base station, the first signal comprising a fallback indication; In response to receiving the first signal, sending, by the first wireless communication device, a second signal to a first Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN) base station, the second signal comprising a connection request; and A third signal is sent by the first wireless communication device to a second wireless communication device, the third signal including a report in response to a connection failure with the first E-UTRAN base station.

2. The method of claim 1 , wherein the report comprises a flag configured to be set to a true value in response to the connection failure with the first E-UTRAN base station being due to voice fallback, and to be set to a false value in response to the connection failure with the first E-UTRAN base station not being due to voice fallback.

3. The method of claim 1, wherein the report comprises: a first field, the first field corresponding to a handover report type, wherein in response to the fallback indication indicating voice fallback, the handover report type of the report is set to EPS fallback failure; and A second field corresponds to the fallback indication.

4. The method according to claim 1, wherein the second wireless communication device is a second E-UTRAN base station or a second NG-RAN base station.

5. The method according to claim 4, further comprising: In response to the connection failure with the first E-UTRAN base station, searching for the second wireless communication device, wherein the report includes an indication that the search did not identify a second E-UTRAN base station.

6. The method according to claim 1, wherein: The first wireless communication device is in an active state, and The report is a Radio Link Failure (RLF) report. The method of claim 1 , wherein the fallback indication corresponds to speech fallback. The method of claim 1 , wherein the fallback indication corresponds to an emergency fallback.

9. A method of wireless communication, the method comprising: receiving, by a first wireless communication device, a first signal from a user equipment (UE), the first signal comprising a connection request; sending, by the first wireless communication device, a second signal to the UE, the second signal comprising an information request; and A third signal is received by the first wireless communication device from the UE, the third signal comprising a report generated in response to a failure to establish a connection between the UE and a second wireless communication device, the report comprising a backoff indication.

10. The method of claim 9, wherein the report comprises a flag configured to be set to a true value in response to the failure to establish the connection between the UE and the second wireless communication device being due to voice fallback, and to be set to a false value in response to the failure to establish the connection between the UE and the second wireless communication device not being due to voice fallback.

11. The method of claim 9, wherein the report further comprises: a first field, the first field corresponding to a handover report type, wherein in response to the fallback indication indicating voice fallback, the handover report type of the report is set to EPS fallback failure; and A second field corresponds to the fallback indication.

12. The method of claim 9, wherein the first wireless communication device is an E-UTRAN base station or a second NG-RAN base station.

13. The method according to claim 12, wherein: The second wireless communication device is a first E-UTRAN base station; The first signal is received in response to the failure to establish the connection between the UE and the second wireless communication device; and The report includes an indication that the search did not identify a second E-UTRAN base station.

14. The method of claim 9, wherein: The UE is in RRC active state, and The report is a Radio Link Failure (RLF) report. The method of claim 9 , wherein the fallback indication corresponds to an emergency fallback.

16. A wireless communication device, comprising: Transceiver; and a processor coupled to the transceiver, wherein the wireless communication device is configured to: receiving a first signal from a first next generation radio access network (NG-RAN) base station, the first signal comprising a fallback indication; in response to receiving the first signal, sending a second signal to a first Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN) base station, the second signal comprising a connection request; as well as A third signal is sent to a second wireless communication device, the third signal including a report in response to a connection failure with the first E-UTRAN base station.

17. The wireless communication device of claim 16, wherein the report comprises a flag configured to be set to a true value in response to the connection failure with the first E-UTRAN base station being due to voice fallback, and to be set to a false value in response to the connection failure with the first E-UTRAN base station not being due to voice fallback.

18. The wireless communication device of claim 16, wherein the report comprises: a first field, the first field corresponding to a handover report type, wherein in response to the fallback indication indicating voice fallback, the handover report type of the report is set to EPS fallback failure; and A second field corresponds to the fallback indication.

19. The wireless communication device of claim 16, wherein the second wireless communication device is a second E-UTRAN base station or a second NG-RAN base station.

20. The wireless communication device according to claim 19, the wireless communication device is further configured to: In response to the connection failure with the first E-UTRAN base station, searching for the second wireless communication device, wherein the report includes an indication that the search did not identify a second E-UTRAN base station.

21. The wireless communication device of claim 16, wherein: The wireless communication device is in an active state, and The report is a Radio Link Failure (RLF) report.

22. The wireless communication device of claim 16, wherein the fallback indication corresponds to voice fallback.

23. The wireless communications apparatus of claim 16, wherein the fallback indication corresponds to an emergency fallback.

24. A wireless communication device, comprising: Transceiver; and a processor coupled to the transceiver, wherein the wireless communication device is configured to: receiving a first signal from a user equipment (UE), the first signal comprising a connection request; sending a second signal to the UE, the second signal comprising an information request; and A third signal is received from the UE, the third signal comprising a report generated in response to a failure to establish a connection between the UE and a second wireless communication device, the report comprising a backoff indication.

25. The wireless communication device of claim 24, wherein the report comprises a flag configured to be set to a true value in response to the failure to establish the connection between the UE and the second wireless communication device being due to voice fallback, and to be set to a false value in response to the failure to establish the connection between the UE and the second wireless communication device not being due to voice fallback.

26. The wireless communication device of claim 24, wherein the report further comprises: a first field, the first field corresponding to a handover report type, wherein in response to the fallback indication indicating voice fallback, the handover report type of the report is set to EPS fallback failure; and A second field corresponds to the fallback indication.

27. The wireless communication device of claim 24, wherein the wireless communication device is an E-UTRAN base station or a second NG-RAN base station.

28. The wireless communication device of claim 24, wherein: The second wireless communication device is a first E-UTRAN base station; The wireless communication device is configured to receive the first signal in response to the failure to establish the connection between the UE and the second wireless communication device; and The report includes an indication that the search did not identify a second E-UTRAN base station.

29. The wireless communication device of claim 24, wherein: The UE is in RRC active state, and The report is a Radio Link Failure (RLF) report.

30. The wireless communications apparatus of claim 24, wherein the fallback indication corresponds to an emergency fallback.

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