Beam failure recovery using contention-based random access

Abstract

The present disclosure relates to beam failure recovery using contention-based random access. The present disclosure relates to performing beam failure recovery using a contention-based random access procedure in a cellular communication system. A wireless device and a cellular base station can establish a cellular link. Beam configuration information indicating an active beam of downlink communications can be provided. The wireless device can detect a beam failure of the active beam. The wireless device can perform a contention-based random access procedure based at least in part on detecting the beam failure of the active beam. The wireless device can provide an indication of the detected beam failure to the cellular base station as part of the contention-based random access procedure.

Description

[0001] This application is a divisional of PCT application entering Chinese national phase, which is International Application No. PCT / CN2018 / 096230, filed on June 28, 2018, entitled “Beam Failure Recovery Using Contention-Based Random Access,” and claims priority to U.S. Provisional Application No. 62 / 692, 1 10, filed on June 29, 2018, the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0002] The present application relates to wireless communication, and more specifically to systems, apparatus and methods for performing beam failure recovery using contention-based random access procedures in a cellular communication system.

[0003] DESCRIPTION OF RELATED ART

[0004] The use of wireless communication systems is expanding rapidly. In recent years, wireless devices such as smart phones and tablets have become increasingly sophisticated. In addition to supporting telephone calls, many mobile devices (i.e., user equipment devices or UEs) now provide access to the Internet, email, text messaging, and navigation using the global positioning system (GPS), and can operate sophisticated, complex applications that utilize these functions. Additionally, there are numerous different wireless communication technologies and wireless communication standards. Some examples of wireless communication standards include GSM, UMTS (e.g., associated with the WCDMA or TD-SCDMA air interfaces), LTE, LTE-Advanced (LTE-A), NR, HSPA, 3GPP2 CDMA2000 (e.g., lxRTT, lxEV-DO, HRPD, eHRPD), IEEE 802.11 (WLAN or Wi-Fi), BLUETOOTH TM , etc.

[0005] The introduction of an ever-increasing number of features and functions in wireless communication devices also requires constant improvements to wireless communication and to wireless communication devices. It is particularly important to ensure the accuracy of signals transmitted and received by user equipment (UE) devices (e.g., by wireless devices such as cellular telephones, base stations, and relay stations used in wireless cellular communications). Thus, improvements in this field are highly desirable.

[0006] For example, some cellular communication systems include the use of beamforming techniques. In such cases, beam configurations can be used to effectively increase the signal strength of transmitted signals in a target direction or area. However, if the beam is not properly directed, a device attempting to receive the beam can not be able to do so. Thus, to handle such scenarios and other possible beam failure scenarios, improvements in beam failure recovery techniques are desirable. SUMMARY

[0007] Embodiments of apparatuses, systems, and methods are provided herein for performing beam failure recovery using a contention-based random access procedure in a cellular communications system.

[0008] According to the techniques described herein, when performing a contention-based random access procedure, an explicit and / or implicit mechanism can be used to indicate a beam failure recovery request.

[0009] In an explicit mechanism, as part of a contention-based random access procedure, a wireless device can be able to include message content that indicates a beam failure recovery request, as well as potentially other information that can be used to reconfigure an active beam for the wireless device. Such information can be provided, for example, using medium access control or radio resource control signaling as part of a message 3 of a contention-based random access procedure.

[0010] In an implicit mechanism, configuration information indicating a set of physical random access channel resources and preambles that are configured to indicate a beam failure recovery request when used to initiate a contention-based random access procedure can be provided to a wireless device by a base station serving a cell for the wireless device. Thus, when a wireless device detects a beam failure of its active beam, the wireless device can use a preamble and physical random access channel resource combination that is configured to indicate a beam failure recovery request to initiate a contention-based random access procedure.

[0011] In either such mechanism, a base station can be able to determine that a wireless device is indicating a beam failure recovery request as part of a contention-based random access procedure. The base station can thus be able to provide beam reconfiguration information to the wireless device in a timely manner. This in turn can help to avoid data transmission failures and / or radio link failures, and / or can improve the throughput and / or power efficiency of communications between the base station and the wireless device.

[0012] It should be noted that the techniques described herein can be implemented in and / or used with a number of different types of devices, including but not limited to base stations, access points, cellular phones, portable media players, tablet computers, wearable devices, and various other computing devices.

[0013] This Summary is intended to provide a brief overview of some of the subject matter described in this document. Accordingly, it will be appreciated that the above-described features are merely examples and should not be construed to narrow the scope or spirit of the subject matter described in this disclosure. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following DETAILED DESCRIPTION, Figures, and Claims. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1An exemplary (and simplified) wireless communication system is shown in accordance with some embodiments;

[0015] Figure 2 An exemplary base station in communication with exemplary wireless user equipment (UE) devices is shown in accordance with some embodiments;

[0016] Figure 3 An exemplary block diagram of a UE in accordance with some embodiments;

[0017] Figure 4 An exemplary block diagram of a base station in accordance with some embodiments;

[0018] Figure 5 A communication flow diagram showing aspects of an exemplary possible method for performing beam failure recovery using a contention-based random access procedure in a cellular communications system in accordance with some embodiments;

[0019] Figure 6 A communication flow diagram showing aspects of an exemplary possible method for performing beam failure recovery using a contention-free random access procedure in a cellular communications system in accordance with some embodiments;

[0020] Figure 7 A communication flow diagram showing aspects of an exemplary possible contention-based random access procedure in accordance with some embodiments; and

[0021] Figures 8 to 10 Further aspects of possible techniques for performing beam failure recovery using a contention-based random access procedure in a cellular communications system in accordance with some embodiments are shown.

[0022] While features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular form disclosed but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter defined by the appended claims. DETAILED DESCRIPTION

[0023] Acronyms

[0024] Various acronyms are used throughout the present disclosure. Definitions of the most prominent acronyms used throughout the present disclosure can appear as follows:

[0025] • UE: User Equipment

[0026] • RE: Radio Frequency

[0027] • BS: Base Station

[0028] • GSM: Global System for Mobile Communications

[0029] • UMTS: Universal Mobile Telecommunication System

[0030] • LTE: Long Term Evolution

[0031] • NR: New Radio

[0032] • TX: Transmission / Transmit

[0033] • RX: Reception / Receive

[0034] • RAT: Radio Access Technology

[0035] • C-RNTI: Cell-Radio Network Temporary Identifier

[0036] • CBRA: Contention Based Random Access

[0037] Terminology

[0038] The following is a glossary of terms that can be found in the present disclosure:

[0039] Storage medium—any of various types of memory devices or storage devices. The term "storage media" is intended to include an installation medium, e.g., a CD-ROM, floppy disks, or tape device; a computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; a nonvolatile memory such as a floppy disk drive, a hard drive, or a flash memory; a register, another like type of storage device; or a compact disk. The memory medium can also include a cache, a processor register, and / or a data buffer. The memory medium can be located in a first computer system in which the programs are executed, or the memory medium can be located in a second different computer system which connects to the first computer system through a network. In the latter instance, the second computer system can provide program instructions to the first computer system for execution. The term "memory medium" can include two or more memory media which can reside in different places, e.g., in different computer systems that are connected through a network. The memory medium can store data which can be executed by one or more of the processors of the computer system. The memory medium can alternatively or additionally store data which is used by one or more of the processors of the computer system.

[0040] Carrier medium—memory medium as described above, as well as a physical transmission medium, such as a bus, network, and / or other physical transmission medium which conveys signals such as electrical, electromagnetic, or digital signals.

[0041] Computer system (or computer) — any of the various types of computing or processing systems, including personal computer systems (PCs), mainframe computer systems, workstations, network appliances, internet-connected appliances, personal digital assistants (PDAs), television systems, grid computing systems, or other devices or combinations thereof. Generally, the term "computer system" can be broadly defined as any device (or combination of devices) that includes at least one processor that executes instructions from a memory medium.

[0042] User equipment (UE) (or “UE device”) — any of various types of computer systems or devices that are mobile or portable and perform wireless communication. Examples of UE devices include mobile phones or smartphones (e.g., iPhone). TM Based on Android TM Phones), tablets (e.g., iPads) TM Samsung Galaxy TM ), portable gaming devices (e.g., Nintendo DS) TM PlayStation Portable TM Gameboy Advance TM iPhone TM Wearable devices (e.g., smartwatches, smart glasses), laptops, PDAs, portable internet devices, music players, data storage devices, or other handheld devices. Generally, the term "UE" or "UE device" can be broadly defined as any electronic device, computing device, and / or telecommunications device (or combination of devices) that is easily transportable by the user and capable of wireless communication.

[0043] A wireless device is any of various types of computer systems or devices that perform wireless communication. A wireless device can be portable (or mobile), or it can be stationary or fixed in a location. A UE is an example of a wireless device.

[0044] A communication device is any of various types of computer systems or devices that perform communication, which may be wired or wireless. A communication device may be portable (or mobile), or it may be stationary or fixed in a location. A wireless device is one example of a communication device. A UE is another example of a communication device.

[0045] Base station (BS) — The term “base station” has the full range of its usual meaning and includes at least a wireless communication station that is installed in a fixed location and used for communication as part of a wireless telephone system or radio system.

[0046] Processing element—refers to various elements or combinations of elements that are capable of performing a function in a device (e.g., a user equipment device or a cellular network device). Processing elements can include, for example, a processor and associated memory, portions or circuits of individual processor cores, entire processor cores, processor arrays, circuits such as an ASIC (application specific integrated circuit), programmable hardware elements such as an FPGA (field programmable gate array), and any of various combinations thereof.

[0047] Wi-Fi—The term “Wi-Fi” has the full breadth of its ordinary meaning and at least includes a wireless communication network or RAT that provides services using wireless LAN (WLAN) access points and that provides connectivity to the Internet through these access points. Most modern Wi-Fi networks (or WLAN networks) are based on IEEE 802.11 standards and marketed under the name “Wi-Fi.” Wi-Fi (WLAN) networks are distinct from cellular networks.

[0048] Automatically—refers to an action or operation performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuitry, programmable hardware elements, ASIC, etc.) without user input directly specifying or performing the action or operation. Thus the term “automatically” is in contrast to “manually,” which requires user input to directly specify or perform the action or operation. For example, a system that determines an action to be performed by a user without user input specifically specifying that action or an operation is performed over the user’s input is performed “automatically.” The user may

[0049] Configured To - Various components can be described as being "configured to" perform one or more tasks. In such contexts, "configured to" is a broad recitation of structure generally meaning "having circuitry that" performs the one or more tasks during operation. As such, a component can be configured to perform one or more tasks even when the component is not currently on. In some contexts, "configured to" can be described as a broad recitation of structure generally meaning "having circuitry that" performs the one or more tasks during operation. As such, a component can be configured to perform one or more tasks even when the component is not currently on. In general, the circuitry forming the structure corresponding to "configured to" can include hardware circuitry.

[0050] For ease of description, various components can be described as performing one or more tasks. Such descriptions should be interpreted as including the phrase "configured to." A component that is configured to perform one or more tasks is expressly intended to invoke the interpretation of that component not invoking the interpretation of 35 U.S.C. § 112, paragraph 6.

[0051] Figure 1 And Figure 2 Example Communication System

[0052] Figure 1 An example (and simplified) wireless communication system in accordance with some embodiments in which various aspects of the present disclosure can be implemented is shown. Note that Figure 1 The system of FIG. 1 is merely one example of a possible system, and these embodiments can be implemented in any of various systems as desired.

[0053] As shown, the example wireless communication system includes a base station 102, which communicates over a transmission medium with one or more (e.g., any number) of user devices 106A, 106B, etc., through 106N. Each user device can be referred to herein as a "user equipment" (UE) or UE device. Thus, the user devices 106 are referred to as UEs or UE devices.

[0054] The base stations 102 can be transceiver base stations (BTSs) or cell sites, and can include hardware and / or software that enables wireless communication with the UEs 106A through 106N. If implemented in the context of LTE, the base stations 102 can be referred to as “eNodeBs” or “eNBs.” If implemented in the context of 5G NR, the base stations 102 can alternatively be referred to as “gNodeBs” or “gNBs.” The base stations 102 can also be equipped to communicate with the network 100 (e.g., a core network of a cellular service provider, a telecommunications network such as a public switched telephone network (PSTN), and / or the Internet, among various possible networks). Accordingly, the base stations 102 can facilitate communications between the user devices and / or between user devices and the network 100. The communication area (or coverage area) of a base station can be referred to as a “cell.” Also as used herein, a base station can be considered to represent the network in the sense that communication with a UE is considered to be communication with the network, where both uplink and downlink communications of the UE are considered.

[0055] The base stations 102 and user devices can be configured to communicate using any of a variety of radio access technologies (RATs), also referred to as wireless communication technologies or telecommunications standards, such as GSM, UMTS (WCDMA), LTE, LTE-Advanced (LTE-A), LAA / LTE-U, 5G NR, 3GPP2, CDMA2000 (e.g., IxRTT, IxEV-DO, HRPD, eHRPD), Wi-Fi, and so on.

[0056] The base stations 102 and other similar base stations operating according to the same or a different cellular communication standard can thus provide service as one or more cell networks that can provide continuous or approximately continuous overlapping service to UEs 106 and similar devices via one or more cellular communication standards over a certain geographic region.

[0057] Note that the UEs 106 are capable of communicating using multiple wireless communication standards. For example, the UEs 106 can be configured to communicate using either or both of a 3GPP cellular communication standard or a 3GPP2 cellular communication standard. In some embodiments, the UEs 106 can be configured to perform beam failure recovery using a contention-based random access procedure, such as according to the various methods described herein. The UEs 106 can also be configured to, or alternatively configured to, communicate using WLAN, BLUETOOTH TMone or more global navigation satellite systems (GNSS, e.g., GPS or GLONASS), one and / or more mobile television broadcasting standards (e.g., ATSC-M / H), etc. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0058] Figure 2 An exemplary user equipment 106 (e.g., one of devices 106A-106N) is shown in communication with base station 102, in accordance with some embodiments. UE 106 can be a device with wireless network connectivity, such as a mobile phone, a handheld device, a wearable device, a computer or tablet, or virtually any type of wireless device. UE 106 can include a processor configured to execute program instructions stored in memory. The UE 106 can perform any of the method embodiments described herein by executing such stored instructions. Alternatively, or additionally, the UE 106 can include a programmable hardware element such as an FPGA or a PLD, which can be configured to perform any of the method embodiments described herein, or any portion of any of the method embodiments described herein. The UE 106 can be configured to communicate using any of multiple wireless communication protocols. For example, the UE 106 can be configured to communicate using two or more of CDMA2000, LTE, LTE-A, 5G NR, WLAN, or GNSS. Other combinations of wireless communication standards are also possible.

[0059] The UE 106 can include one or more antennas that use one or more wireless communication protocols to communicate in accordance with one or more RAT standards. In some embodiments, the UE 106 can share one or more portions of receive chains and / or transmit chains between multiple wireless communication standards. The shared radio can include a single antenna, or can include multiple antennas used in performance of wireless communication (e.g., for MIMO). In general, a radio can include any combination of baseband processors, analog radio frequency (RF) signal processing circuitry (e.g., including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g., for digital modulation and other digital processing). Similarly, the radio can implement one or more receive and transmit chains using the aforementioned hardware.

[0060] In some embodiments, the UE 106 can include separate transmit and / or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. As another possibility, the UE 106 can include one or more radio components that are shared among multiple wireless communication protocols, as well as one or more radio components that are used exclusively by a single wireless communication protocol. For example, the UE 106 can include a shared radio for communicating using either LTE or CDMA2000 IxRTT (or LTE or NR, or LTE or GSM), as well as separate radio components for communicating using each of Wi-Fi and BLUETOOTH TM Other configurations are also possible.

[0061] Figure 3 Block diagram of an example UE device

[0062] Figure 3 A block diagram illustrating an example UE 106, in accordance with some embodiments, is shown. As shown, the UE 106 can include a system on chip (SOC) 300, which can include portions for various purposes. For example, as shown, the SOC 300 can include a processor 302, which can execute program instructions for the UE 106, and a display circuit 304, which can perform graphics processing and provide display signals to a display 360. The processor 302 can also be coupled to a memory management unit (MMU) 340, which can be configured to receive addresses from the processor 302 and translate those addresses to locations in memory (for example, memory 306, read only memory (ROM) 350, NAND flash memory 310) and / or to other circuitry or devices, such as the display circuit 304, wireless communication circuit 330, connector I / F 320, and / or display 360. The MMU 340 can be configured to perform memory protection and page table translation or set up. In some embodiments, the MMU 340 can be included as a portion of the processor 302.

[0063] As shown, the SOC 300 can be coupled to various other circuitry of the UE 106. For example, the UE 106 can include various types of memory (for example, including NAND flash 310), a connector interface 320 (for example, for coupling to a computer system, docking station, charging station, and the like), a display 360, and wireless communication circuitry 330 (for example, for LTE, LTE-A, NR, CDMA2000, BLUETOOTH TMWi-Fi, GPS, etc.). The UE device 106 can include at least one antenna, for example 335a, and possibly multiple antennas (for example, as illustrated by antennas 335a and 335b), for performing wireless communication with base stations and / or other devices. Antennas 335a and 335b are shown by way of example, and the UE device 106 can include fewer or more antennas.

[0064] In general, the one or more antennas are collectively referred to as antennas 335. For example, the UE device 106 can use the antennas 335 with the radio circuitry 330 to perform wireless communication. As described above, in some embodiments, the UE can be configured to use multiple wireless communication standards for wireless communication.

[0065] The UE 106 can include hardware and software components for implementing methods of the UE 106 to perform beam failure recovery using a contention-based random access procedure, such as further described later herein. The processor 302 of the UE device 106 can be configured to implement part or all of the methods described herein, for example, by executing program instructions stored in a memory medium (for example, a non-transitory computer-readable memory medium). In other embodiments, one or more processors 302 can be configured as programmable hardware elements, such as FPGAs (field-programmable gate arrays) or as ASICs (application-specific integrated circuits). Additionally or alternatively, the processor 302 of the UE device 106 can be configured to implement Figure 3 the methods and techniques described herein by programmable logic

[0066] In some embodiments, the radio 330 can include separate controllers that are dedicated to controlling communications for various respective RAT standards. For example, as shown in Figure 3 the radio 330 can include a Wi-Fi controller 352, a cellular controller (for example, an LTE and / or LTE-A controller) 354, and a BLUETOOTH controller 356, and in at least some embodiments one or more or all of these controllers can be implemented as respective integrated circuits (ICs or chips) that communicate with one another and with the SOC 300 (and more specifically the processor 302). For example, the Wi-Fi controller 352 can communicate with the cellular controller 354 over a cell-ISM link or WCI interface, and / or the BLUETOOTH controller 356 can communicate with the cellular controller 354 over a Bluetooth-Cellular link or BC1 interface. TM TM ​Controller 356 can communicate with cellular controller 354 via a cell-ISM link or the like. Although three separate controllers are shown within radio component 330, other implementations with fewer or more similar controllers for various different RATs can be implemented in UE device 106.

[0067] Furthermore, implementation schemes in which the controller can perform functions associated with various radio access technologies are envisioned. For example, according to some implementation schemes, in addition to hardware and / or software components for performing cellular communications, the cellular controller 354 may also include hardware and / or software components for performing one or more activities associated with Wi-Fi, such as Wi-Fi preamble detection, and / or the generation and transmission of Wi-Fi physical layer preamble signals.

[0068] Figure 4 – Block diagram of an exemplary base station

[0069] Figure 4 A block diagram of an exemplary base station 102 according to some implementation schemes is shown. It should be noted that... Figure 4 The base station shown is merely one example of a possible base station. As illustrated, base station 102 may include a processor 404 capable of executing program instructions specific to base station 102. Processor 404 may also be coupled to a memory management unit (MMU) 440 or other circuitry or device, which may be configured to receive addresses from processor 404 and translate those addresses into locations in memory (e.g., memory 460 and read-only memory (ROM) 450).

[0070] Base station 102 may include at least one network port 470. Network port 470 may be configured to be coupled to a telephone network and provide access rights as described above. Figure 1 and Figure 2 The telephone network described herein includes multiple devices such as UE device 106. Network port 470 (or an additional network port) may also be configured, or alternatively configured, to be coupled to a cellular network, such as the core network of a cellular service provider. The core network may provide mobility-related services and / or other services to multiple devices such as UE device 106. In some cases, network port 470 may be coupled to the telephone network via the core network, and / or the core network may provide the telephone network (e.g., in other UE devices served by the cellular service provider).

[0071] The base station 102 can include at least one antenna 434, and possibly multiple antennas. The one or more antennas 434 can be configured to operate as a wireless transceiver and can be further configured to communicate with UE devices 106 via the radio 430. The antennas 434 communicate with the radio 430 via communication chains 432. The communication chains 432 can be receive chains, transmit chains, or both. The radio 430 can be designed to communicate via various wireless telecommunication standards, including but not limited to NR, LTE, LTE-A WCDMA, CDMA2000, etc. The processor 404 of the base station 102 can be configured to implement and / or support a portion or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, the processor 404 can be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit), or a combination thereof. In the case of certain RATs, such as Wi-Fi, the base station 102 can be designed to be an access point (AP), in which case the network port 470 can be implemented to provide access to a wide area network and / or one or more local area networks, e.g., it can include at least one Ethernet port, and the radio 430 can be designed to communicate according to the Wi-Fi standards. The base station 102 can operate according to the various methods disclosed herein for performing beam failure recovery using a contention-based random access procedure in a cellular communications system.

[0072] Figure 5 Beam failure recovery using a contention-based random access procedure

[0073] Some wireless communication technologies can utilize beamforming for at least some communications. Such technologies can reduce power requirements and / or increase effective communication range of wireless communications in a particular direction or region. However, due to mobility, changing medium conditions, and / or for any of a variety of other reasons, sometimes beam configurations can fail in use, which can result in service interruption or loss. Accordingly, techniques for recovering from such beam failures (e.g., selecting a new beam configuration) can be important.

[0074] Figure 5 FIG. 1 is a communication flow diagram illustrating a method for a wireless device (e.g., a cellular base station and a wireless user equipment (UE) device, as shown as one possibility) to perform beam failure recovery using a contention-based random access procedure in a cellular communications system, in accordance with some embodiments.

[0075] Figure 5Aspects of the methods of FIGS. 1-3 can be implemented by wireless devices and cellular base stations, such as the UEs 106 and BSs 102 shown and described with respect to the various figures herein, or more generally, can be implemented in connection with any of the computer systems or devices shown in the above figures as desired. Note that while described in ways that involve using communication technologies and / or features associated with LTE, LTE-A, NR, and / or 3GPP specification documents, such descriptions are not intended to be limiting of the present disclosure, and aspects of the methods of FIGS. 1-3 can be used in any suitable wireless communication system as desired. Figure 5 Aspects of the methods of FIGS. 1-3 can be implemented by wireless devices and cellular base stations, such as the UEs 106 and BSs 102 shown and described with respect to the various figures herein, or more generally, can be implemented in connection with any of the computer systems or devices shown in the above figures as desired. Note that while described in ways that involve using communication technologies and / or features associated with LTE, LTE-A, NR, and / or 3GPP specification documents, such descriptions are not intended to be limiting of the present disclosure, and aspects of the methods of FIGS. 1-3 can be used in any suitable wireless communication system as desired. Figure 5 Aspects of the methods of FIGS. 1-3 can be implemented by wireless devices and cellular base stations, such as the UEs 106 and BSs 102 shown and described with respect to the various figures herein, or more generally, can be implemented in connection with any of the computer systems or devices shown in the above figures as desired. Note that while described in ways that involve using communication technologies and / or features associated with LTE, LTE-A, NR, and / or 3GPP specification documents, such descriptions are not intended to be limiting of the present disclosure, and aspects of the methods of FIGS. 1-3 can be used in any suitable wireless communication system as desired. Figure 5 The methods of FIGS. 1-3 can operate as follows.

[0076] At 502, the wireless device and the cellular base station can establish a wireless link. According to some embodiments, the wireless link can comprise a cellular link according to 5G NR. For example, the wireless device can establish a session with an AMF entity of a cellular network through a gNB that provides radio access to the cellular network. Note that according to various embodiments, the cellular network can also or alternatively operate according to another cellular communication technology (e.g., LTE, UMTS, CDMA2000, GSM, etc.).

[0077] Establishing the wireless link can comprise establishing an RRC connection with the serving cellular base station according to at least some embodiments. Establishing the RRC connection can comprise configuring various parameters for communicating between the wireless device and the cellular base station, establishing context information for the wireless device, and / or any of various other possible features, e.g., involving establishing an air interface for the wireless device to communicate with a cellular network associated with the cellular base station. After establishing the RRC connection, the wireless device can operate in an RRC connected state.

[0078] As part of establishing an RRC connection and / or in one or more other manners (e.g., via broadcast system information, via a medium access control (MAC) control element, etc.), a base station can provide beam configuration information to a wireless device. The beam configuration information can include any of a variety of information to support beam usage between the cellular base station and the wireless device. As one possibility, the beam configuration information can indicate one or more active beams (e.g., a set of active beams) for downlink communications from the cellular base station. The beam configuration information can also indicate one or more other configured (but not active) beams that the wireless device can be able to (and can be expected to, at least in some cases) monitor (e.g., using reference symbols associated with those configured beams provided by the cellular base station).

[0079] As another possibility, the beam configuration information can indicate one or more resource pools that can be used in conjunction with beam failure recovery techniques. For example, the cellular base station can determine a pool of physical random access channel (PRACH) resources, and / or can indicate dedicated PRACH preambles that are dedicated for use by the wireless device to indicate that a beam failure has occurred. Since such resources / preambles are specifically provided to the wireless device, the wireless device can use them to perform a contention-free random access (CFRA) procedure to indicate a beam failure and request beam failure recovery. In some cases, the pool can include a set of at least one resource / preamble per configured beam, e.g., such that the resource and preamble used can implicitly indicate a preferred beam to use as an active beam when performing beam failure recovery. As another example, the cellular base station can determine a pool of PRACH resources, and / or can indicate dedicated PRACH preambles that are generally available (e.g., available to the wireless device and one or more other wireless devices) to indicate that a beam failure has occurred. Since such resources / preambles are not provided solely to the wireless device, but can be shared among at least a subset of wireless devices served by the cellular base station, the wireless device can use them to perform a contention-based random access (CBRA) procedure to indicate a beam failure and request beam failure recovery. The pool can include resources / preambles associated with a particular configured beam (e.g., such that initiating a contention-based random access procedure using a PRACH preamble and resource associated with a particular beam can indicate a request to activate the particular beam), and / or can include resources / preambles that are configured to generally indicate that a beam failure has occurred and are not associated with a particular configured beam.

[0080] Note that the cellular base station can also provide an indication of one or more pools of PRACH preambles and resources usable for one or more other contention-based random access procedure triggers according to the cellular link with the cellular base station. For example, resources / preamble pools for uplink data arrival, uplink synchronization, and / or other purposes can also be provided. According to at least some embodiments, such resources / preamble pools can be different and separate from the beam failure recovery specific pool of PRACH preambles and resources, for example, to help the cellular base station differentiate between contention-based random access procedures performed by the wireless device for different reasons.

[0081] In 504, the wireless device can detect a beam failure of the active beam. Detecting the beam failure can be based at least in part on the wireless device monitoring beam failure detection reference symbols (e.g., reference symbols associated with the active beam), for example, in the course of its communication with the cellular base station. For example, the wireless device can perform measurements (e.g., periodically) to determine values of reference signal received power (RSRP) and / or one or more other signal strength and / or signal quality metrics of the active beam using the beam failure detection reference symbols. If the RSRP (and / or other metric values) are worse than a configured threshold (e.g., which can be configured as part of the beam configuration information, determined by the wireless device, specified by a standard specification document, or otherwise determined in any of a variety of possible ways), the wireless device can determine that a beam failure has occurred for the active beam. Note that variations of this technique and / or any of a variety of other techniques for determining when a beam failure has occurred are possible.

[0082] In some cases, the wireless device can determine a preferred beam in connection with detecting the beam failure of the active beam, for example, among the configured beams indicated in the beam configuration information. For example, as previously noted, the wireless device can monitor reference symbols associated with the configured beams, and can be able to determine RSRP and / or other signal strength / quality metric values for each candidate beam. Thus, as one possibility, a beam can be considered a preferred beam if it satisfies one or more predetermined requirements (e.g., in various possibilities, RSRP is above a certain threshold, and / or is greater than the RSRP of the active beam by a certain margin). Other techniques (or variations of this technique) can also or alternatively be used to determine one or more preferred beams.

[0083] At 506, the wireless device can initiate a contention-based random access procedure, e.g., based at least in part on detecting the beam failure of the active beam. According to at least some embodiments, the contention-based random access procedure can be initiated by the wireless device providing a PRACH preamble (“message 1”), and can also include the cellular base station providing a random access response (“message 2”) in response to the PRACH preamble, the wireless device following up with a transmission (“message 3”) scheduled by the random access response (which can include device identifying information, such as a cell radio network temporary identifier (C-RNTI)), and the cellular base station responding with a contention resolution message (“message 4”) to complete the contention-based random access procedure. Note that in some cases, a short contention-based random access procedure can also or alternatively be possible. For example, in some cases, the C-RNTI information can be included with the PRACH preamble, and the cellular base station can directly respond to the PRACH preamble with the contention resolution message.

[0084] As part of the contention-based random access procedure, the wireless device can indicate that it has detected a beam failure of the active beam and / or can request beam failure recovery. For example, as previously mentioned, in some cases the wireless device can be able to use a PRACH resource and / or PRACH preamble configured to indicate that a beam failure has occurred and request beam failure recovery to initiate a CBRA procedure, such as a PRACH resource and PRACH preamble selected from a beam failure recovery specific pool of PRACH preambles and resources. Thus, the cellular base station can receive the PRACH preamble, and can be able to determine that the wireless device is experiencing a beam failure of the active beam based on the PRACH preamble and / or the resource on which the PRACH preamble is received. In this case, the cellular base station can provide RRC beam set reconfiguration information, a MAC control element adjusting the activated beam set, and / or other beam configuration information indicating a new active beam for downlink communications from the cellular base station along with contention resolution (e.g., as message 4 in a normal contention-based random access procedure, or possibly as message 2 in a short contention-based random access procedure if the C-RNTI information is also set with the PRACH preamble configured to indicate that a beam failure has occurred).

[0085] As another (e.g., additional or alternative) possibility, the wireless device can provide an explicit indication that a beam failure has occurred and / or request beam failure recovery as part of a contention-based random access procedure. For example, as part of scheduling a transmission (message 3), the wireless device can provide message content that indicates any or all of the following: a request to perform beam failure recovery, an indication of one or more preferred beams (e.g., if determined), beam measurement results for the active beam, carrier identification information for a carrier associated with the active beam that has failed (e.g., if multiple carriers are configured and active), and / or bandwidth part identification information for a bandwidth part associated with the active beam that has failed (e.g., if multiple bandwidth parts are configured and active), among various possible indications. According to various embodiments, such information can be provided using MAC control elements and / or RRC information elements. In this case, the cellular base station can provide RRC beam set reconfiguration information, MAC control elements that adjust the active beam set, and / or other beam configuration information that indicates a new active beam for downlink communications from the cellular base station, along with contention resolution, e.g., a message 4 provided in response to message 3.

[0086] Thus, a wireless device can indicate that a beam failure has occurred and request beam failure recovery using a contention-based random access procedure. At least according to some embodiments, such techniques can help the network quickly distinguish a contention-based random access procedure based on a beam failure request from contention-based random access procedures performed for other reasons (e.g., uplink data arrival, uplink synchronization, etc.), and thus perform a serving beam reconfiguration for a wireless device experiencing an active beam failure more quickly than if a method for indicating that a beam failure has occurred using a contention-based random access procedure were not provided.

[0087] Additionally, at least according to some embodiments, such techniques can improve the efficiency of PRACH resource and preamble usage for beam failure recovery, e.g., as compared to techniques in which a contention-free random access procedure is used for reporting a beam failure request. For example, for a CFRA procedure based beam failure request report, dedicated PRACH / preamble resources for beam failure requests can be provided to each wireless device, while for a CBRA procedure based beam failure request report, PRACH / preamble resources for beam failure requests can be shared among multiple wireless devices, potentially improving PRACH resource usage efficiency.

[0088] Figures 6 to 10 — Additional Information

[0089] Provided is Figures 6 to 10 and the information below, which illustrate techniques involving Figure 5Further considerations and possible implementation details of the methods, and are not intended to be limiting overall. Various changes and alternatives are possible and should be considered within the scope of the present disclosure.

[0090] Beam failure recovery can be performed by a wireless device that detects a beam failure, e.g., of an active beam configured for the wireless device. Beam failure recovery can be performed via a random access channel (RACH) procedure, such as a CFRA procedure or a CBRA procedure. Figure 6 is a communication flow diagram illustrating a CFRA procedure based technique for performing beam failure recovery between a gNB and a UE.

[0091] As shown, a gNB can provide RRC configuration information to a UE, including resource configuration information indicating resources that can be used to transmit an uplink signal for beam recovery. These can include UE-specific dedicated PRACH / preamble resources, and an association between PRACH / preamble resources and candidate beams. Upon beam failure detection (e.g., by monitoring beam failure detection reference symbols), a wireless device can perform new candidate beam identification, e.g., by monitoring beam identification reference symbols (e.g., synchronization signal blocks (SSBs) or channel state information reference symbols (CSI-RSs)) and determining candidate beams with signal strength above a threshold. Note that, at least according to some embodiments, the UE can determine how to select a preferred beam among multiple active beams when multiple beams are valid. The UE can then perform a beam failure recovery request transmission, e.g., using uplink resources configured by the gNB. The beam failure recovery request transmission can indicate a new candidate beam identified by the UE, e.g., by using a PRACH / preamble resource associated with that candidate beam. In response to the beam failure recovery request transmission, the gNB can respond on a PDCCH scrambled by the C-RNTI of the UE for a particular duration of time (e.g., possibly including providing beam reconfiguration information indicating a new active beam).

[0092] Accordingly, the gNB can be able to distinguish such a request from other RACH procedures via RACH resources and preambles for a CFRA procedure, and upon receiving a beam failure recovery request, the gNB can be able to understand the preferred beam of the UE from a configured set of candidate beams (e.g., those different from the current serving beam used to monitor the serving PDCCH), and can be able to reconfigure the serving beam accordingly.

[0093] However, in some cases, such CFRA procedure based techniques for performing beam failure recovery between a gNB and a UE can not be successful, can not be possible, or can otherwise be unavailable for use. In such cases, CBRA procedure based techniques for performing beam failure recovery between a gNB and a UE can be used. For example, if no or incomplete UE specific beam failure recovery configuration information is provided (e.g., no BeamFailureRecoveryConfig, or reveryControlStceSetld, or reverySearchSpaceld configuration), or if no active beam is detected (e.g., no candidate beam has an RSRP above an RSRP threshold), or if a CFRA procedure performed at beam recovery timer expiration is not successful, a wireless device can attempt to perform beam failure recovery using a CBRA procedure.

[0094] Figure 7 is a communication flow diagram illustrating a CBRA procedure, such as can be used to perform beam failure recovery between a gNB and a UE if a set of PRACH / preamble resources for the CBRA procedure are common for all events (e.g., including beam failure request, uplink data arrival, and uplink synchronization). In this case, the gNB can not be able to distinguish between beam failure recovery events and other events that can cause a UE to perform a CBRA procedure. As a result, the gNB can not be able to immediately identify an inappropriate serving beam configuration, and data transmission failure, further beam link failure, and / or potential radio link failure can occur.

[0095] Accordingly, at least according to some embodiments, it can be advantageous to provide a UE with a mechanism to indicate that a beam failure has occurred and to request beam failure recovery as part of a CBRA procedure. Such a mechanism can allow a gNB to perform reconfiguration of a serving beam for a UE in a more timely manner upon successful completion of a CBRA procedure for beam failure recovery. Figures 8 to 10 Several such possible mechanisms are illustrated.

[0096] Figure 8is a communication flow diagram illustrating a CBRA procedure such as can be used to perform beam failure recovery between a gNB and a UE, where an explicit beam failure recovery request is indicated, e.g., in message 3 of the CBRA procedure. The explicit indication can be provided using a new MAC CE or RRC message. The content can include any or all of the following: a beam failure recovery request, an indication of a preferred beam set from the UE side, beam measurement results, and / or a carrier ID or bandwidth part (BWP) ID for which beam failure recovery is requested, and various possible types of information. Upon successful message 3 reception, the gNB can thus be able to perform a serving beam reconfiguration in the next downlink transmission (e.g., message 4).

[0097] Figures 9 to 10 is a communication flow diagram illustrating a CBRA procedure such as can be used to perform beam failure recovery between a gNB and a UE, where an implicit beam failure recovery request is indicated, e.g., by using PRACH / preamble resources configured to indicate a beam failure recovery request that initiates CBRA. In such methods, configuration information can be provided by the gNB to the UE, indicating separate pools of PRACH / preamble resources for beam failure recovery and other purposes. The beam failure recovery specific PRACH / preamble resources can be shared among multiple UEs. According to various embodiments, the configuration information can be provided through RRC broadcast or dedicated RRC configuration. For broadcast configuration information, the PRACH / preamble resources and the link to SSBs can be cell-specific and common to all UEs. For dedicated configuration information, the PRACH / preamble resources can be the same or different from the SIB PRACH configuration. If different, the PRACH configuration can be linked to SSBs or CSI-RS.

[0098] In Figure 9 In the mechanisms shown, the gNB can be able to identify that the CBRA procedure indicates a beam failure recovery request from message 1, but can still need UE identification information that can be provided in message 3 to resolve contention.

[0099] In Figure 10In the illustrated mechanism, in addition to using PRACH / preamble resources configured to indicate a beam failure recovery request initiating CBRA, the UE can also include its ID (e.g., C-RNTI) in the message 1 along with the preamble. Thus, the gNB can be able to identify that the CBRA procedure indicates a beam failure recovery request and can be able to determine the UE ID from the message 1. Thus, upon receiving the message 1, the gNB can use downlink control information scrambled by the UE’s C-RNTI to directly resolve contention and confirm the beam failure recovery request (e.g., including beam reconfiguration information). Note that if this mechanism is used, if the gNB only detects the RACH preamble but not the C-RNTI, the gNB can still be able to transmit a random access response message 2, followed by the exchange of message 3 and message 4, resolving contention in a similar manner to the mechanism of Figure 9

[0100] Thus, such mechanisms can help the network to distinguish beam failure recovery requests from other RACH events during CBRA procedures and thus increase the likelihood of timely performing a serving beam reconfiguration to reduce data transmission failures and avoid radio link failures. Additionally, at least according to some embodiments, such techniques can allow for more efficient PRACH and preamble resource usage for beam failure recovery requests, e.g., since providing PRACH / preamble resource pools shared among UEs for beam failure recovery requests can represent more efficient resource usage than providing dedicated UE-specific PRACH / preamble resources for beam failure recovery requests.

[0101] Note also that such techniques can also or alternatively be used to help configure transitions between beams even when no beam failure technically occurs, e.g., to improve throughput and / or power efficiency of communications between a base station and a wireless device, if desired. For example, such techniques (or variations of such techniques) can be used by a wireless device and a base station to transition from an active beam having marginal signal quality (e.g., but not so poor as to be determined to have failed) to a beam having significantly better signal strength / quality.

[0102] In the following, further example embodiments are provided.

[0103] ​One set of embodiments can include an apparatus comprising a processing element configured to cause a wireless device to establish a cellular link with a cellular base station, receive beam configuration information for the cellular link, wherein the beam configuration information indicates one or more active beams for downlink communications from the cellular base station, detect a beam failure of an active beam, and perform a contention-based random access procedure based at least in part on detecting the beam failure of the active beam, wherein an indication of the detected beam failure is provided by the wireless device to the cellular base station as part of the contention-based random access procedure.

[0104] According to some embodiments, the processing element is further configured to cause the wireless device to receive beam reconfiguration information for the cellular link from the cellular base station based at least in part on the indication of the detected beam failure, wherein the beam reconfiguration information indicates a new active beam for downlink communications from the cellular base station, wherein the beam reconfiguration information is provided via one of radio resource control (RRC) beam set reconfiguration information or medium access control (MAC) control element adjusting an active subset of beams.

[0105] According to some embodiments, the processing element is further configured to cause the wireless device to receive an indication of a beam failure recovery specific pool of PRACH preambles and resources, wherein the indication of the beam failure recovery specific pool of PRACH preambles and resources is received via one of wireless device specific radio resource control configuration information or broadcast configuration information, and receive an indication of one or more pools of PRACH preambles and resources available for one or more other contention-based random access procedure triggers according to the cellular link with the cellular base station, wherein the beam failure recovery specific pool of PRACH preambles and resources and the one or more pools of PRACH preambles and resources available for one or more other contention-based random access procedure triggers include different PRACH preambles and resources.

[0106] According to some embodiments, the indication of the detected beam failure is provided by initiating the contention-based random access procedure using physical random access channel (PRACH) resources and PRACH preambles configured to indicate the detected beam failure, wherein the PRACH resources and the PRACH preambles used to initiate the contention-based random access procedure are selected from a beam failure recovery specific pool of PRACH preambles and resources.

[0107] According to some embodiments, the beam failure recovery specific pool of PRACH preambles and resources includes one or more PRACH preamble and resource combinations associated with a particular beam, where initiating the contention-based random access procedure using the PRACH preamble and resource combination associated with the particular beam indicates a request to activate the particular beam.

[0108] According to some embodiments, the indication of the detected beam failure is provided by including message content configured to indicate the detected beam failure, where the message content configured to indicate the detected beam failure is included in a message 3 of the contention-based random access procedure.

[0109] According to some embodiments, the message content configured to indicate the detected beam failure includes an indication of one or more of: a request to perform beam failure recovery; an indication of one or more preferred beams; a beam measurement result for the active beam; carrier identification information for a carrier associated with the detected beam failure; or bandwidth part (BWP) identification information for a BWP associated with the detected beam failure.

[0110] According to some embodiments, the beam failure of the active beam is detected based at least in part on a measurement of beam failure detection reference symbols provided by the cellular base station.

[0111] Another set of embodiments can include a wireless device comprising: an antenna; a radio operably coupled to the antenna; and a processing element operably coupled to the radio; wherein the wireless device is configured to: establish a cellular link with a cellular base station, receive beam configuration information for the cellular link, where the beam configuration information indicates an active beam for downlink communications from the cellular base station; detect a beam failure of the active beam; and perform a contention-based random access procedure based at least in part on detecting the beam failure of the active beam, where the wireless device provides a request for beam failure recovery during the contention-based random access procedure.

[0112] According to some embodiments, the wireless device is further configured to: receive beam reconfiguration information for the cellular link from the cellular base station based at least in part on the indication of the detected beam failure, where the beam reconfiguration information indicates a new active beam for downlink communications from the cellular base station.

[0113] According to some embodiments, the beam configuration information further indicates a set of physical random access channel (PRACH) resources and PRACH preambles configured to indicate a detected beam failure, wherein the indication of the detected beam failure is provided by initiating the contention-based random access procedure using one or more of the PRACH resources and PRACH preambles selected from the set of PRACH resources and PRACH preambles configured to indicate a detected beam failure.

[0114] According to some embodiments, the wireless device is further configured to provide wireless device identification information to the cellular base station in a message 1 of the contention-based random access procedure, and receive contention resolution and beam reconfiguration information in a message 2 of the contention-based random access procedure based at least in part on the wireless device identification information included in the message 1 of the contention-based random access procedure.

[0115] According to some embodiments, the indication of the detected beam failure is provided using medium access control or radio resource control signaling in a message 3 of the contention-based random access procedure.

[0116] According to some embodiments, the beam configuration information further indicates a set of configured candidate beams, wherein the wireless device is further configured to determine a preferred beam from the set of configured candidate beams, wherein the wireless device provides an indication of the preferred beam to the cellular base station as part of the contention-based random access procedure.

[0117] Yet another set of embodiments can include a cellular base station comprising: an antenna; a radio operably coupled to the antenna; and a processing element operably coupled to the radio; wherein the cellular base station is configured to: establish a cellular link with a wireless device; provide beam configuration information for the cellular link to the wireless device, wherein the beam configuration information indicates an active beam for downlink communication to the wireless device; receive a request for beam failure recovery from the wireless device during a contention-based random access procedure initiated by the wireless device; and provide beam reconfiguration information for the cellular link to the wireless device based at least in part on the request for beam failure recovery, wherein the beam reconfiguration information indicates a new active beam for downlink communication to the wireless device.

[0118] According to some embodiments, the cellular base station is further configured to: determine a set of physical random access channel (PRACH) resources and PRACH preambles configured to indicate a beam failure when used to initiate a contention-based random access procedure, wherein the beam configuration information further indicates the set of PRACH resources and PRACH preambles configured to indicate a beam failure when used to initiate a contention-based random access procedure; wherein the request for beam failure recovery comprises initiation of the contention-based random access procedure by the wireless device using a PRACH resource and PRACH preamble selected from the set of PRACH resources and PRACH preambles configured to indicate a beam failure when used to initiate a contention-based random access procedure.

[0119] According to some embodiments, the cellular base station is further configured to: provide beam configuration information to one or more other wireless devices, the beam configuration information indicating a set of PRACH resources and PRACH preambles configured to indicate a beam failure when used to initiate a contention-based random access procedure, wherein the set of PRACH resources and PRACH preambles configured to indicate a beam failure when used to initiate a contention-based random access procedure is shared between the wireless device and the one or more other wireless devices.

[0120] According to some embodiments, the cellular base station is further configured to: receive wireless device identification information with the PRACH preamble used by the wireless device to initiate the contention-based random access procedure; and provide contention resolution and the beam reconfiguration information in response to the PRACH preamble based at least in part on the wireless device identification information including the PRACH preamble used by the wireless device to initiate the contention-based random access procedure.

[0121] According to some embodiments, the cellular base station is further configured to: provide a random access response to the wireless device in response to the PRACH preamble used by the wireless device to initiate the contention-based random access procedure; receive wireless device identification information in a transmission of the contention-based random access procedure scheduled by the random access response; and provide contention resolution and the beam reconfiguration information in response to the transmission of the contention-based random access procedure scheduled by the random access response.

[0122] According to some embodiments, wherein the request for beam failure recovery comprises medium access control or radio resource control signaling received by the cellular base station in a message 3 of the contention-based random access procedure.

[0123] Yet another example embodiment can include a method comprising: performing, by a wireless device, any or all parts of the preceding examples.

[0124] Another example embodiment can include a device comprising: an antenna; a radio coupled to the antenna; and a processing element operably coupled to the radio, wherein the device is configured to implement any or all portions of any of the preceding examples.

[0125] Another set of example embodiments can include a non-transitory computer- accessible memory medium comprising program instructions that, when executed at a device, cause the device to implement any or all portions of any of the preceding examples.

[0126] Another set of example embodiments can include a computer program comprising instructions for performing any or all portions of any of the preceding examples.

[0127] Another set of example embodiments can include an apparatus comprising means for performing any or all portions of any of the preceding examples.

[0128] Another set of example embodiments can include an apparatus comprising a processing element configured to cause a wireless device to perform any or all portions of any of the preceding examples.

[0129] Embodiments of the application can be realized in any of various forms. For example, in some embodiments, the application can be realized as a computer- implemented method, a computer-readable memory medium, or a computer system. In other embodiments, the application can be realized using one or more custom-designed hardware devices such as ASICs. In other embodiments, the application can be realized using one or more programmable hardware elements such as FPGAs.

[0130] In some embodiments, a non-transitory computer-readable memory medium (e.g., a non-transitory memory element) can be configured to have stored thereon program instructions and / or data, wherein the program instructions, if executed by a computer system, cause the computer system to perform a method, such as any of the method embodiments described herein, or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein, or any combination of such subsets.

[0131] In some embodiments, a device (e.g., a UE) can be configured to include a processor (or a set of processors) and a memory medium (or memory element), where the memory medium stores program instructions, where the processor is configured to read and execute the program instructions from the memory medium, where the program instructions are executable to implement any of the various method embodiments described herein (or any combination of the method embodiments described herein, or any subset of any of the method embodiments described herein, or any combination of such subsets). The device can be implemented in any of a variety of forms.

[0132] While the above embodiments have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be construed to include all such variations and modifications as falling within the true spirit and scope of the present disclosure.

Claims

1. An apparatus for wireless communication, comprising: a memory; and at least one processor coupled to the memory and configured to perform operations when executing instructions stored in the memory, the operations comprising: establishing a cellular link with a cellular base station, receiving beam configuration information for the cellular link, wherein the beam configuration information indicates one or more beams for downlink communications from the cellular base station; detecting a beam failure of a first beam; transmitting, to the cellular base station, a physical random access preamble (message 1) as part of a contention-based random access procedure based at least in part on the beam failure of the first beam; receiving a random access response (message 2) that schedules a transmission of a message 3 of the contention-based random access procedure; and transmitting, to the cellular base station, the message 3, wherein the message 3 includes an indication of the beam failure.

2. The apparatus of claim 1, wherein the indication of the beam failure includes an indication of a request to perform a beam failure recovery.

3. The apparatus of claim 1, wherein the indication of the beam failure includes a cell radio network temporary identifier (C-RNTI) of a cell in which the beam failure is occurring.

4. The apparatus of claim 1, wherein the beam configuration information further indicates a configured set of candidate beams.

5. The apparatus of claim 1, wherein the indication of the beam failure includes one or more of: an indication of one or more preferred beams; a beam measurement of the first beam; carrier identification information of a carrier associated with the detected beam failure; or bandwidth part (BWP) identification information of a BWP associated with the detected beam failure.

6. The apparatus of claim 1, wherein the beam failure of the first beam is detected based at least in part on a measurement of a beam failure detection reference symbol provided by the cellular base station.

7. The apparatus of claim 1, wherein the at least one processor is further configured to perform operations comprising: receiving, from the cellular base station, beam reconfiguration information for the cellular link based at least in part on the indication of the detected beam failure, wherein the beam reconfiguration information indicates a new beam for downlink communications from the cellular base station, wherein the beam reconfiguration information is provided via one of radio resource control (RRC) beam set reconfiguration information or medium access control (MAC) control element that adjusts a subset of beams that are activated.

8. An integrated circuit, comprising: at least one processor configured to cause a wireless device to: establish a cellular link with a cellular base station, receive beam configuration information for the cellular link, wherein the beam configuration information indicates one or more beams for downlink communications from the cellular base station; detect a beam failure of a first beam; transmit, to the cellular base station, a physical random access preamble (message 1) as part of a contention-based random access procedure based at least in part on the beam failure of the first beam; ​ receiving a random access response (message 2) that schedules transmission of a message 3 of the contention-based random access procedure; and transmitting the message 3 to the cellular base station, wherein the message 3 includes an indication of the beam failure.

9. The integrated circuit of claim 8, wherein the indication of the beam failure includes an indication of a request to perform beam failure recovery.

10. The integrated circuit of claim 8, wherein the indication of the beam failure includes a cell radio network temporary identifier (C-RNTI) of a cell in which the beam failure is occurring.

11. The integrated circuit of claim 8, wherein the beam configuration information further indicates a configured set of candidate beams.

12. The integrated circuit of claim 8, wherein the indication of the beam failure includes one or more of: an indication of one or more preferred beams; a beam measurement result for the first beam; carrier identification information for a carrier associated with the detected beam failure; or bandwidth part (BWP) identification information for a BWP associated with the detected beam failure.

13. The integrated circuit of claim 8, wherein the beam failure of the first beam is detected based at least in part on a measurement of beam failure detection reference symbols provided by the cellular base station.

14. The integrated circuit of claim 8, wherein the at least one processor is further configured to cause the wireless device to: receive, from the cellular base station, beam reconfiguration information for the cellular link based at least in part on the indication of the detected beam failure, wherein the beam reconfiguration information indicates a new beam for downlink communications from the cellular base station, wherein the beam reconfiguration information is provided via one of radio resource control (RRC) beam set reconfiguration information or medium access control (MAC) control element that adjusts a subset of beams that are activated.

15. A method for operating a wireless device, comprising: by a wireless device: establishing a cellular link with a cellular base station, receiving beam configuration information for the cellular link, wherein the beam configuration information indicates one or more beams for downlink communications from the cellular base station; detecting a beam failure of a first beam; transmitting, to the cellular base station, a physical random access preamble (message 1) as part of a contention-based random access procedure based at least in part on the beam failure of the first beam; receiving a random access response (message 2) that schedules transmission of a message 3 of the contention-based random access procedure; and transmitting the message 3 to the cellular base station, wherein the message 3 includes an indication of the beam failure.

16. The method of claim 15, wherein the indication of the beam failure includes an indication of a request to perform beam failure recovery.

17. The method of claim 15, wherein the indication of the beam failure includes a cell radio network temporary identifier (C-RNTI) of a cell in which the beam failure is occurring.

18. The method of claim 15, wherein the beam configuration information further indicates a configured set of candidate beams.

19. The method of claim 15, wherein the indication of the beam failure comprises one or more of: an indication of one or more preferred beams; a beam measurement result for the first beam; carrier identification information for a carrier associated with the detected beam failure; or bandwidth part (BWP) identification information for a BWP associated with the detected beam failure.

20. The method of claim 15, wherein the beam failure of the first beam is detected based at least in part on a measurement of a beam failure detection reference symbol provided by the cellular base station.

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