Receiving cell restriction rules for beam failure report responses

Abstract

The invention relates to receiving cell restriction rules for beam failure report responses. An example method, which may be performed by a user equipment (UE), includes detecting an occurrence of a threshold number of beam failures of a connection between the UE and a set of cells; identifying candidate beams for restoring a connection between the UE and the set of cells in response to detecting an occurrence of a threshold number of beam failures; transmitting a beam failure recovery (BFR) request to one or more cells in the set of cells, the beam failure recovery (BFR) request comprising an identification of the candidate beam; receiving a BFR response from a cell of the set of cells in response to transmitting the BFR request, wherein the BFR response is received according to a restriction rule; and continuing communication with the set of cells based on the BFR response.

Description

[0001] This application is a divisional application of the patent application with application number 202080077959.9, application date November 13, 2020, and invention name “Receiving cell restriction rules for beam failure report response”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. application No. 17 / 096,873, filed on November 12, 2020, which claims the benefit of and priority to U.S. Provisional Application No. 62 / 936,390, filed on November 15, 2019, entitled “Beam Failure Report Response Receiving Cell Restriction Rule,” both of which are assigned to the assignee of this application and the contents of which are expressly incorporated herein by reference as if fully set forth below and for all applicable purposes. Technical Field

[0004] Aspects of the present disclosure relate to wireless communications and, more particularly, to techniques for responding to beam failure reports based on cell restriction rules. Background Art

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name a few.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is an enhancement to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0007] However, as the demand for mobile broadband access continues to grow, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should also apply to other multiple access technologies and the telecommunication standards that employ them. Summary of the Invention

[0008] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the disclosure as expressed in the appended claims, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide advantages, including improved beam fault detection.

[0009] Certain aspects of the subject matter described in this disclosure can be implemented in a method of wireless communication by a user equipment (UE). The method generally includes: detecting occurrence of a threshold number of beam failures for a connection between the UE and a failed cell in a set of cells; identifying candidate beams for restoring the connection between the UE and the set of cells in response to detecting the occurrence of the threshold number of beam failures; transmitting a beam failure recovery (BFR) request to one or more cells in the set of cells, the beam failure recovery (BFR) request including an identification of the candidate beams; receiving a BFR response from a cell in the set of cells in response to transmitting the BFR request, wherein the BFR response is received according to a restriction rule; and continuing communication with the set of cells based on the BFR response.

[0010] Certain aspects of the subject matter described in this disclosure can be implemented in a method of wireless communication by a network entity. The method generally includes: receiving a beam failure recovery (BFR) request from a user equipment (UE), the beam failure recovery (BFR) request including an identification of a candidate beam; generating a BFR response based on the identified candidate beam; transmitting the BFR response to the UE based on a restriction rule; and communicating with the UE based on the identified candidate beam.

[0011] Aspects of the present disclosure provide apparatuses, devices, processors, and computer-readable media for performing the methods described herein.

[0012] Aspects of the present disclosure provide apparatuses, devices, processors, and computer-readable media for performing techniques and methods that may be complementary to the operations performed by a UE (eg, a BS) described herein.

[0013] To accomplish the foregoing and related ends, one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and accompanying drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are indicative of but a few of the various ways in which the principles of the various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to understand in detail the manner in which the above-recited features of the present disclosure may be understood, a more particular description of the content briefly summarized above may be obtained by reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only certain typical aspects of the disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

[0015] Figure 1 is a schematic illustration of a wireless communication system in accordance with some aspects.

[0016] Figure 2 is a conceptual illustration of an example of a radio access network in accordance with some aspects.

[0017] Figure 3 is a block diagram illustrating a wireless communication system supporting multiple-input multiple-output (MIMO) communication.

[0018] Figure 4 is a schematic illustration of the organization of radio resources in an air interface utilizing orthogonal frequency division multiplexing (OFDM) according to some embodiments.

[0019] Figure 5 is a schematic illustration of an OFDM air interface designed with scalable parameters, according to some aspects of the present disclosure.

[0020] Figure 6is a block diagram conceptually illustrating an example of a hardware implementation of a scheduling entity according to some aspects of the present disclosure.

[0021] Figure 7 is a block diagram conceptually illustrating an example of a hardware implementation for a user equipment (UE) according to some aspects of the present disclosure.

[0022] Figure 8 is a flow diagram illustrating example operations for wireless communications by a UE in accordance with certain aspects of the present disclosure.

[0023] Figure 9 is a flow diagram illustrating example operations for wireless communications by a network entity, in accordance with certain aspects of the present disclosure.

[0024] Figure 10 is a call flow diagram illustrating messages exchanged between a UE and a network entity for beam failure reporting in accordance with certain aspects of the present disclosure.

[0025] Figure 11 Illustrated are communications devices that may include various components configured to perform operations for the techniques disclosed herein, in accordance with aspects of the present disclosure.

[0026] Figure 12 Illustrated are communications devices that may include various components configured to perform operations for the techniques disclosed herein, in accordance with aspects of the present disclosure.

[0027] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized in other aspects without specific recitation. DETAILED DESCRIPTION

[0028] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for beam failure reporting and response based on receive cell restriction rules.

[0029] The following description provides examples of beam failure reporting and responses based on receive cell restriction rules in a communication system, and is not intended to limit the scope, applicability, or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements discussed without departing from the scope of this disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Furthermore, features described with reference to some examples may be combined in other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. Furthermore, the scope of this disclosure is intended to cover such apparatus or methods practiced using other structures, functionalities, or both, in addition to or in addition to the various aspects of this disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be implemented by one or more elements of a claim. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

[0030] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, subcarrier, frequency channel, tone, subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs.

[0031] The techniques described herein can be used for various wireless networks and radio technologies. Although various aspects may be described herein using terms typically associated with 3G, 4G, and / or new radio (e.g., 5G NR) wireless technologies, various aspects of the present disclosure may be applied in communication systems based on other generations.

[0032] NR access can support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth, millimeter wave (mmW), massive machine type communication (MTC) targeting non-backward compatible MTC technology, and / or mission-critical services targeting ultra-reliable low latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet corresponding quality of service (QoS) requirements. In addition, these services can coexist in the same subframe.

[0033] The electromagnetic spectrum is typically subdivided into various classes, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz–7.125 GHz) and FR2 (24.25 GHz–52.6 GHz). Frequencies between FR1 and FR2 are typically referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often (interchangeably) referred to as the “sub-6 GHz band” in various documents and articles. Similar naming issues sometimes arise regarding FR2, which is often (interchangeably) referred to as the “millimeter wave” band in various documents and articles, although it is different from the extremely high frequency (EHF) band (30 GHz–300 GHz) identified as the “millimeter wave” band by the International Telecommunication Union (ITU).

[0034] In view of the above aspects, unless otherwise specified, it should be understood that the term sub-6 GHz, etc., if used herein, can broadly refer to frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. In addition, unless otherwise specified, it should be understood that the term "millimeter wave", etc., if used herein, can broadly refer to frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies.

[0035] NR supports beamforming and the beam direction can be dynamically configured. MIMO transmission with precoding can also be supported. MIMO configuration in the DL can support up to 8 transmit antennas (with multi-layer DL transmission of up to 8 streams) and up to 2 streams per UE. Multi-layer transmission of up to 2 streams per UE can be supported. Aggregation of multiple cells can be supported using up to 8 serving cells.

[0036] RAT: Radio Access Technology. A type of technology or communication standard used for radio access and communication over a wireless air interface. Just some examples of RATs include GSM, UTRA, E-UTRA (LTE), Bluetooth, and Wi-Fi.

[0037] NR: New Radio. Generally refers to 5G technology and the new radio access technology being defined and standardized by 3GPP in Release 15.

[0038] Legacy compatibility: may refer to the ability of a 5G network to provide connectivity to pre-5G devices, and the ability of a 5G device to obtain connectivity to pre-5G networks.

[0039] Multimode device: A device that can provide simultaneous connectivity across different networks, such as 5G, 4G, and Wi-Fi networks.

[0040] CA: Carrier Aggregation. 5G networks can provide aggregation of sub-6 GHz carriers, carriers above 6 GHz, mmWave carriers, etc., all controlled by a single integrated MAC layer.

[0041] MR-AN: Multi-RAT Radio Access Network. A single radio access network may provide one or more cells for each of multiple RATs and may support inter-RAT and intra-RAT mobility and aggregation.

[0042] MR-CN: Multi-RAT Core Network. A single common core network can support multiple RATs (e.g., 5G, LTE, and WLAN). In some examples, a single 5G control plane can support the user planes of multiple RATs by leveraging software-defined networking (SDN) technology in the core network.

[0043] SDN: Software Defined Networking. A dynamic, adaptive network architecture that can be managed by abstracting lower-layer network functions, making control of network functions directly programmable.

[0044] SDR: Software Defined Radio. A dynamically adaptable radio architecture in which many of the radio's signal processing components (such as amplifiers, modulators, demodulators, etc.) are replaced by software functions. SDR simply reprograms a single radio device to enable it to communicate using different and separate waveforms and RATs.

[0045] mmWave: millimeter wave. Generally refers to a high-frequency band above 24 GHz, which can provide a very large bandwidth.

[0046] Beamforming: Directional signal transmission or reception. For beamformed transmissions, the amplitude and phase of each antenna in an antenna array may be precoded or controlled to create a desired (eg, directional) pattern of constructive and destructive interference in the wavefront.

[0047] MIMO: Multiple Input, Multiple Output. MIMO is a multi-antenna technology that exploits multipath signal propagation to multiply the information-carrying capacity of a wireless link by sending multiple simultaneous streams using multiple antennas at the transmitter and receiver. At the multi-antenna transmitter, a suitable precoding algorithm (scaling the amplitude and phase of the respective streams) is applied (in some examples, based on known channel state information). At the multi-antenna receiver, the different spatial signatures of the respective streams (and in some examples, known channel state information) can enable the streams to be separated from each other.

[0048] In single-user MIMO, a transmitter sends one or more streams to the same receiver, thereby exploiting the capacity gains associated with using multiple Tx, Rx antennas in rich scattering environments where channel variations can be tracked.

[0049] The receiver can track these channel changes and provide corresponding feedback to the transmitter. This feedback can include channel quality information (CQI), the number of preferred data streams (e.g., rate control, rank indicator (RI)), and precoding matrix index (PMI).

[0050] Massive MIMO: A MIMO system with a very large number of antennas (e.g., larger than an 8x8 array).

[0051] MU-MIMO: A multi-antenna technology in which a base station in communication with a large number of UEs can exploit multipath signal propagation to increase overall network capacity by increasing throughput and spectral efficiency and reducing required transmission energy.

[0052] The transmitter can attempt to increase capacity by using its multiple transmit antennas simultaneously and transmitting to multiple users using the same allocated time-frequency resources. The receiver can transmit feedback including a quantized version of the channel so that the transmitter can schedule the receivers with good channel spacing. The transmitted data is precoded to maximize user throughput and minimize inter-user interference.

[0053] AS: Access Stratum. A functional grouping consisting of parts in the radio access network and parts in the UE, and the access technology-specific protocols between these parts (i.e., the specific physical medium between the UE and the radio access network used to carry information).

[0054] NAS: Non-Access Stratum. A protocol between the UE and the core network that is not terminated in the radio access network.

[0055] RAB: Radio Access Bearer. A service provided by the access stratum to the non-access stratum for transmitting user information between the UE and the core network.

[0056] Network slicing: A wireless communication network can be divided into multiple virtual service networks (VSNs) or network slices, which are separately configured to better suit the needs of different types of services. Some wireless communication networks can be divided according to eMBB, IoT, and URLLC services, for example.

[0057] eMBB: Enhanced Mobile Broadband. Generally, eMBB refers to the continued advancement of improvements to existing broadband wireless communication technologies (such as LTE). eMBB provides (generally continuously) increased data rates and increased network capacity.

[0058] IoT: Internet of Things. Generally speaking, this refers to the convergence of several technologies with different use cases into a single common infrastructure. Most discussions of IoT focus on machine-type communication (MTC) devices.

[0059] URLLC: Ultra-Reliable Low Latency Communication. Sometimes also equivalently referred to as Mission Critical Communication. Reliability refers to the probability of successfully delivering a given number of bytes within 1ms given channel quality. Ultra-reliability refers to a high target reliability, for example, greater than 99.999% packet success rate. Latency refers to the time it takes to successfully deliver an application layer packet or message. Low latency refers to a low target latency, for example, 1ms or even 0.5ms (in contrast, the target for eMBB can be 4ms).

[0060] MTC: Machine Type Communication. A form of data communication involving one or more entities that does not necessarily require human interaction. Optimization for MTC services differs from human-to-human communication because MTC services generally involve different market scenarios, data communication, lower cost and effort, potentially very large numbers of communicating terminals, and largely low traffic volumes per terminal. (See 3GPP TS 22.368.)

[0061] Duplex: A point-to-point communication link in which both endpoints can communicate with each other in both directions. Full-duplex means that both endpoints can communicate with each other simultaneously. Half-duplex means that only one endpoint can send information to the other endpoint at a time. In wireless links, full-duplex channels generally rely on physical separation of the transmitter and receiver and interference cancellation techniques. Full-duplex emulation is usually achieved for wireless links by utilizing frequency division duplexing (FDD) or time division duplexing (TDD). In FDD, the transmitter and receiver at each endpoint operate at different carrier frequencies. In TDD, transmissions in different directions on a given channel are separated from each other using time division multiplexing. That is, sometimes the channel is dedicated to transmission in one direction, and sometimes the channel is dedicated to transmission in the other direction.

[0062] OFDM: Orthogonal Frequency Division Multiplexing. The air interface can be defined in terms of a two-dimensional grid of resource elements, separated in frequency by defining a set of closely spaced frequency tones or subcarriers, and in time by defining a sequence of symbols with a given duration. By setting the spacing between tones based on the symbol rate, inter-symbol interference can be eliminated. OFDM channels provide high data rates by distributing data streams across multiple subcarriers in parallel.

[0063] CP: Cyclic Prefix. Multipath environments degrade the orthogonality between subcarriers because symbols received from reflected or delayed paths may overlap into subsequent symbols. CP addresses this problem by copying the tail of each symbol and appending it to the front of the OFDM symbol. This ensures that any multipath components from the previous symbol fall within the effective guard time at the beginning of each symbol and can be discarded.

[0064] Scalable parameter design: In OFDM, to maintain orthogonality between subcarriers or tones, the subcarrier spacing is equal to the inverse of the symbol period. Scalable parameter design refers to the network's ability to select different subcarrier spacings and, accordingly, the symbol period for each spacing. The symbol period should be short enough so that the channel does not vary significantly within each period, preserving orthogonality and limiting inter-subcarrier interference.

[0065] RSMA: Resource Spread Multiple Access. A non-orthogonal multiple access scheme typically characterized by small data bursts without grants in the uplink, where signaling overhead is a critical issue, e.g., for IoT.

[0066] LBT: Listen Before Talk. An unscheduled, contention-based multiple access technology in which a device monitors or listens to a carrier to determine if it is available before transmitting on it. Some LBT techniques utilize signaling such as Request to Send (RTS) and Clear to Send (CTS) to reserve a channel for a given duration of time.

[0067] D2D: Device-to-Device. Also known as point-to-point (P2P), D2D uses direct links between neighboring devices (i.e., without passing through a base station, relay station, or other node) to discover and communicate with neighboring devices. D2D enables mesh networking and device-to-network relay functionality. Some examples of D2D technologies include Bluetooth pairing, Wi-Fi Direct, Miracast, and LTE-D Direct.

[0068] IAB: Integrated Access and Backhaul. Some base stations can be configured as IAB nodes, where the radio spectrum can be used for both the access link (i.e., the radio link with the UE) and the backhaul link. This approach is sometimes referred to as wireless self-backhaul. By using wireless self-backhaul (rather than requiring each new base station deployment to have its own hardwired backhaul connection), the radio spectrum used for communications between the base station and the UE can be utilized for backhaul communications, enabling the rapid and easy deployment of highly dense small cell networks.

[0069] QoS: Quality of Service. The aggregate effect of service performance that determines user satisfaction with a service. QoS is characterized by the combined aspects of performance factors applicable to all services, such as service operability performance; service accessibility performance; service maintainability performance; service integrity performance; and other factors specific to each service.

[0070] Blockchain: A distributed database and transaction processing technology with certain characteristics that provides a secure and reliable record of transactions in a manner that is highly resistant to fraud or other attacks. When a transaction occurs, many copies of the transaction record are sent to other participants in the network, each of whom simultaneously confirms the transaction through mathematical calculations. Based on these records, each block is accepted using a scoring algorithm. A block is a group or batch of transaction records, including a timestamp and hash of the previous block, linking each block to another. This string of blocks forms a blockchain. In wireless communication networks, especially those with large numbers of IoT devices, blockchain can improve the security and trust of any type of transaction or instruction between devices.

[0071] The various concepts presented throughout this disclosure can be implemented across a wide variety of telecommunication systems, network architectures, and communication standards. Figure 1 By way of illustrative example and not limitation, various aspects of the present disclosure are described with reference to a wireless communication system 100. The wireless communication system 100 includes three interacting domains: a core network 102, a radio access network (RAN) 104, and a user equipment (UE) 106. The wireless communication system 100 enables the UE 106 to perform data communications with an external data network 110, such as, but not limited to, the Internet.

[0072] The RAN 104 may implement any suitable wireless communication technology or technologies to provide radio access to the UE 106. As one example, the RAN 104 may operate in accordance with the 3rd Generation Partnership Project (3GPP) New Radio (NR) specifications, commonly referred to as 5G. As another example, the RAN 104 may operate under a hybrid of 5G NR and Evolved Universal Terrestrial Radio Access Network (eUTRAN) standards, commonly referred to as LTE. 3GPP refers to this hybrid RAN as the Next Generation RAN, or NG-RAN. Of course, many other examples may be utilized within the scope of the present disclosure.

[0073] As illustrated, the RAN 104 includes a plurality of base stations 108. In a broad sense, a base station is a network element in a radio access network that is responsible for radio transmission and reception to and from UEs in one or more cells. A base station may be referred to variously by those skilled in the art as a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), a Node B (NB), an evolved Node B (eNB), a g Node B (gNB), or some other suitable terminology in different technologies, standards, or contexts.

[0074] The radio access network 104 is further illustrated as supporting wireless communications for a plurality of mobile devices. A mobile device may be referred to as a user equipment (UE) in the 3GPP standard, but may also be referred to by those skilled in the art as a mobile station (MS), subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal (AT), mobile terminal, wireless terminal, remote terminal, handset, terminal, user agent, mobile client, client, or some other suitable terminology. A UE may be a device (e.g., a mobile device) that provides a user with access to network services.

[0075] Within this document, a "mobile" device does not necessarily need to have mobile capabilities and can be stationary. The term mobile device or mobile equipment refers broadly to a wide variety of devices and technologies. A UE may include several hardware structural components sized, shaped, and arranged to facilitate communication; such components may include antennas, antenna arrays, RF chains, amplifiers, one or more processors, and the like electrically coupled to each other. For example, some non-limiting examples of mobile devices include mobile devices, cellular (cell) phones, smart phones, Session Initiation Protocol (SIP) phones, laptops, personal computers (PCs), notebooks, netbooks, smartbooks, tablets, personal digital assistants (PDAs), and a wide variety of embedded systems, e.g., corresponding to the "Internet of Things" (IoT). Additionally, mobile devices may be cars or other transportation vehicles, remote sensors or actuators, robots or robotic devices, satellite radios, global positioning system (GPS) devices, object tracking devices, drones, multicopters, quadcopters, remote control devices, consumer and / or wearable devices (such as glasses), wearable cameras, virtual reality devices, smart watches, health or fitness trackers, digital audio players (e.g., MP3 players), cameras, game consoles, etc. Mobile devices may also be digital home or smart home devices, such as home audio, video, and / or multimedia devices, appliances, vending machines, smart lighting devices, home security systems, smart meters, etc. Mobile devices may also be smart energy devices, security devices, solar panels or solar arrays, municipal infrastructure devices that control electricity, lighting, water, etc. (e.g., smart grids); industrial automation and enterprise devices; logistics controllers; agricultural equipment; military defense equipment, vehicles, aircraft, ships, and weapons, etc. Furthermore, mobile devices may provide connected health or telemedicine support, such as remote health care. Telehealth devices may include telehealth monitoring devices and telehealth supervisory devices, whose communications may be given priority or prioritized access over other types of information, for example, in the form of prioritized access for critical service data transmission and / or associated QoS for critical service data transmission.

[0076] The wireless communications between the RAN 104 and the UE 106 may be described as utilizing an air interface. Transmissions over the air interface from a base station (e.g., base station 108) to one or more UEs (e.g., UE 106) may be referred to as downlink (DL) transmissions. According to certain aspects of the present disclosure, the term downlink may refer to point-to-multipoint transmissions originating at a scheduling entity (described further below; e.g., base station 108). Another way to describe this approach may be to use the term broadcast channel multiplexing. Transmissions from a UE (e.g., UE 106) to a base station (e.g., base station 108) may be referred to as uplink (UL) transmissions. According to further aspects of the present disclosure, the term uplink may refer to point-to-point transmissions originating at a scheduled entity (described further below; e.g., UE 106).

[0077] In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., base station 108) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, a scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communications, UE 106 (which may be a scheduled entity) may utilize resources allocated by scheduling entity 108.

[0078] Base station 108 is not the only entity that can serve as a scheduling entity. That is, in some examples, a UE can serve as a scheduling entity, thereby scheduling resources for one or more scheduled entities (e.g., one or more other UEs).

[0079] like Figure 1 , a scheduling entity 108 may broadcast downlink traffic 112 to one or more scheduled entities 106. Broadly speaking, a scheduling entity 108 is a node or device responsible for scheduling traffic in a wireless communication network, including downlink traffic 112 and, in some examples, uplink traffic 116 from one or more scheduled entities 106 to the scheduling entity 108. On the other hand, a scheduled entity 106 is a node or device that receives downlink control information 114 (including, but not limited to, scheduling information (e.g., grants), synchronization or timing information), or other control information from another entity in the wireless communication network, such as the scheduling entity 108.

[0080] Generally speaking, base stations 108 may include a backhaul interface for communicating with a backhaul portion 120 of a wireless communication system. Backhaul 120 may provide a link between base stations 108 and core network 102. Furthermore, in some examples, a backhaul network may provide interconnection between respective base stations 108. Various types of backhaul interfaces may be employed, such as a direct physical connection using any suitable transport network, a virtual network, and the like.

[0081] The core network 102 may be part of the wireless communication system 100 and may be independent of the radio access technology used in the RAN 104. In some examples, the core network 102 may be configured according to a 5G standard (e.g., 5GC). In other examples, the core network 102 may be configured according to a 4G Evolved Packet Core (EPC), or any other suitable standard or configuration.

[0082] Now refer to Figure 2 , a schematic illustration of RAN 200 is provided by way of example and not limitation. In some examples, RAN 200 may be similar to that described above and in Figure 1 The geographic area covered by the RAN 200 may be divided into cellular regions (cells) that are uniquely identifiable by user equipment (UE) based on an identity broadcast from an access point or base station. Figure 2 Illustrated are macro cells 202, 204, and 206, and a small cell 208, each of which may include one or more sectors (not shown). A sector is a sub-area of a cell. All sectors within a cell are served by the same base station. Radio links within a sector may be identified by a single logical identifier belonging to that sector. In a cell divided into sectors, multiple sectors within the cell may be formed by antenna groups, where each antenna is responsible for communicating with UEs in a portion of the cell.

[0083] exist Figure 2 In the example, two base stations 210 and 212 are shown in cells 202 and 204; and a third base station 214 is shown controlling a remote radio head (RRH) 216 in cell 206. That is, the base stations may have integrated antennas or may be connected to antennas or RRHs by feeder cables. In the illustrated example, cells 202, 204, and 126 may be referred to as macro cells because base stations 210, 212, and 214 support cells with large sizes. In addition, base station 218 is shown in a small cell 208 (e.g., a micro cell, a pico cell, a femto cell, a home base station, a Home NodeB, a Home eNodeB, etc.), which may overlap with one or more macro cells. In this example, cell 208 may be referred to as a small cell because base station 218 supports cells with relatively small sizes. Cell sizing may be accomplished based on system design and component constraints.

[0084] It is understood that the radio access network 200 may include any number of wireless base stations and cellular cells. In addition, relay nodes may be deployed to extend the size or coverage area of a given cellular cell. Base stations 210, 212, 214, 218 provide wireless access points to the core network for any number of mobile devices. In some examples, base stations 210, 212, 214, and / or 218 may be similar to those described above and in Figure 1 The same as the base station / scheduling entity 108 illustrated in FIG.

[0085] Figure 2 Further included is a quadcopter or drone 220 that can be configured to act as a base station. That is, in some examples, the cell may not necessarily be stationary, and the geographic area of the cell may move based on the location of a mobile base station (such as quadcopter 220).

[0086] Within the RAN 200, cells may include UEs that may be in communication with one or more sectors of each cell. In addition, each base station 210, 212, 214, 218, and 220 may be configured to provide connectivity to the core network 102 (see FIG. 1 ) for all UEs in the corresponding cell. Figure 1 ) access point. For example, UEs 222 and 224 may be in communication with base station 210; UEs 226 and 228 may be in communication with base station 212; UEs 230 and 232 may be in communication with base station 214 via RRH 216; UE 234 may be in communication with base station 218; and UE 236 may be in communication with mobile base station 220. In some examples, UEs 222, 224, 226, 228, 230, 232, 234, 236, 238, 240, and / or 242 may be in communication with the mobile base station 220 described above and in Figure 1 The UE / scheduled entity 106 is the same as that illustrated in FIG.

[0087] In some examples, a mobile network node (e.g., quadcopter 220) can be configured to function as a UE. For example, quadcopter 220 can operate within cell 202 by communicating with base station 210.

[0088] In a further aspect of RAN 200, sidelink signals may be used between UEs without relying on scheduling or control information from a base station. For example, two or more UEs (e.g., UEs 226 and 228) may communicate with each other using peer-to-peer (P2P) or sidelink signals 227 without relaying the communication through a base station (e.g., base station 212). In a further example, UE 238 is illustrated as communicating with UEs 240 and 242. Here, UE 238 may serve as a scheduling entity or primary sidelink device, and UEs 240 and 242 may serve as scheduled entities or non-primary (e.g., secondary) sidelink devices. In yet another example, a UE may serve as a scheduling entity in a device-to-device (D2D), peer-to-peer (P2P), or vehicle-to-vehicle (V2V) network, and / or a mesh network. In the mesh network example, UEs 240 and 242 may optionally communicate directly with each other in addition to communicating with scheduling entity 238. Thus, in a wireless communication system with scheduled access to time-frequency resources and having a cellular configuration, a P2P configuration, or a mesh configuration, a scheduling entity and one or more scheduled entities may communicate using the scheduled resources.

[0089] In the radio access network 200, the ability of a UE to communicate independently of its location while moving is called mobility. The various physical channels between the UE and the radio access network are typically managed by an access and mobility management function (AMF, not illustrated). Figure 1 The AMF is established, maintained and released under the control of the core network 102 in the core network, which may include a security context management function (SCMF) that manages the security context of both the control plane and the user plane functionalities and a security anchor function (SEAF) that performs authentication.

[0090] In various implementations, the air interface in the radio access network 200 may utilize licensed spectrum, unlicensed spectrum, or shared spectrum. Licensed spectrum generally provides exclusive use of a portion of the spectrum by a mobile network operator purchasing a license from a government regulator. Unlicensed spectrum provides shared use of a portion of the spectrum without the need for a government-granted license. While access to unlicensed spectrum generally still requires adherence to some technical regulations, any operator or device may gain access. Shared spectrum may fall between licensed and unlicensed spectrum, where technical regulations or restrictions may be required to access the spectrum, but the spectrum may still be shared by multiple operators and / or multiple RATs. For example, a license holder of a portion of licensed spectrum may provide licensed shared access (LSA) to share that spectrum with other parties, e.g., with access obtained under conditions determined by the appropriate license holder.

[0091] The air interface in the radio access network 200 may utilize one or more duplexing algorithms. Duplexing refers to a point-to-point communication link in which both endpoints can communicate with each other in both directions. Full-duplexing means that both endpoints can communicate with each other simultaneously. Half-duplexing means that only one endpoint can send information to the other endpoint at a time. In wireless links, full-duplex channels generally rely on physical isolation between the transmitter and receiver, as well as appropriate interference cancellation techniques. Full-duplex emulation is typically achieved for wireless links by utilizing frequency division duplexing (FDD) or time division duplexing (TDD). In FDD, transmissions in different directions operate at different carrier frequencies. In TDD, transmissions in different directions on a given channel are separated from each other using time division multiplexing. That is, at some times, the channel is dedicated to transmissions in one direction, while at other times, the channel is dedicated to transmissions in the other direction, where the direction can change very quickly, for example, several times per time slot.

[0092] In some aspects of the present disclosure, the scheduling entity and / or the scheduled entity may be configured for beamforming and / or multiple-input multiple-output (MIMO) techniques. Figure 3 An example of a wireless communication system 300 supporting MIMO is illustrated. In a MIMO system, a transmitter 302 includes multiple transmit antennas 304 (e.g., N transmit antennas), and a receiver 306 includes multiple receive antennas 308 (e.g., M receive antennas). Thus, there are N×M signal paths 308 from the transmit antennas 304 to the receive antennas 310. Each of the transmitter 302 and the receiver 306 can be implemented, for example, in the scheduling entity 108, the scheduled entity 106, or any other suitable wireless communication device.

[0093] The use of such multi-antenna technology enables wireless communication systems to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing can be used to transmit different data streams (also referred to as layers) simultaneously on the same time-frequency resources. These data streams can be transmitted to a single UE to increase the data rate or to multiple UEs to increase the total system capacity, the latter being called multi-user MIMO (MU-MIMO). This is achieved by spatially precoding each data stream (i.e., multiplying the data streams by different weights and phase shifts) and then transmitting each spatially precoded stream through multiple transmit antennas on the downlink. The spatially precoded data streams arrive at the UE(s) with different spatial signatures that enable each UE to recover one or more data streams intended for the UE. On the uplink, each UE transmits a spatially precoded data stream, which enables the base station to identify the source of each spatially precoded data stream.

[0094] The number of data streams or layers corresponds to the rank of the transmission. In general, the rank of the MIMO system 300 is limited to the lower of the number of transmit or receive antennas 304 or 308. In addition, the channel conditions at the UE and other considerations (such as the available resources at the base station) may also affect the transmission rank. For example, the rank (and therefore, the number of data streams) assigned to a particular UE on the downlink may be determined based on a rank indicator (RI) transmitted from the UE to the base station. The RI may be determined based on the antenna configuration (e.g., the number of transmit and receive antennas) and the measured signal-to-interference-and-noise ratio (SINR) on each receive antenna. The RI may indicate, for example, the number of layers that can be supported under the current channel conditions. The base station may use the RI together with resource information (e.g., available resources and the amount of data to be scheduled for the UE) to assign a transmission rank to the UE.

[0095] In a time division duplex (TDD) system, UL and DL are reciprocal, with each using different time slots of the same frequency bandwidth. Therefore, in a TDD system, the base station can assign a rank for DL MIMO transmission based on UL SINR measurements (e.g., based on a sounding reference signal (SRS) or other pilot signal transmitted from the UE). Based on the assigned rank, the base station can then transmit a CSI-RS using a separate C-RS sequence for each layer to provide multi-layer channel estimation. Based on the CSI-RS, the UE can measure the channel quality across layers and resource blocks and feed back CQI and RI values to the base station for use in updating the rank and assigning REs for future downlink transmissions.

[0096] In the simplest case, Figure 3 , a rank-2 spatial multiplexing transmission on a 2x2 MIMO antenna configuration will transmit one data stream from each transmit antenna 304. Each data stream follows a different signal path 308 to each receive antenna 310. Receiver 306 can then reconstruct the data streams using the signals received from each receive antenna 308.

[0097] The air interface in the radio access network 200 may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of various devices. For example, the 5G NR specification utilizes orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) to provide multiple access for UL transmissions from UEs 222 and 224 to the base station 210, and provides multiplexing for DL transmissions from the base station 210 to one or more UEs 222 and 224. In addition, for UL transmissions, the 5G NR specification provides support for discrete Fourier transform spread OFDM (DFT-s-OFDM) with CP (also known as single carrier FDMA (SC-FDMA)). However, within the scope of the present disclosure, multiplexing and multiple access are not limited to the above schemes and may be provided using time division multiple access (TDMA), code division multiple access (CDMA), frequency division multiple access (FDMA), sparse code multiple access (SCMA), resource spread multiple access (RSMA), or other appropriate multiple access schemes. Furthermore, multiplexing of DL transmissions from base station 210 to UEs 222 and 224 may be provided using time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), sparse code multiplexing (SCM), or other suitable multiplexing schemes.

[0098] Will refer to Figure 4 Various aspects of the present disclosure are described using the OFDM waveforms schematically illustrated in

[15] . Those skilled in the art will appreciate that various aspects of the present disclosure can be applied to DFT-s-OFDMA waveforms in substantially the same manner as described below. That is, while some examples of the present disclosure may focus on OFDM links for clarity, it will be appreciated that the same principles can also be applied to DFT-s-OFDMA waveforms.

[0099] In this disclosure, a frame refers to a 10 ms duration used for wireless transmission, where each frame includes 10 subframes of 1 ms each. On a given carrier, there may be one set of frames in the UL and another set of frames in the DL. Figure 4 , illustrates an expanded view of an exemplary DL subframe 402 showing an OFDM resource grid 404. However, as will be readily appreciated by those skilled in the art, the PHY transmission structure for any particular application may differ from the examples described herein depending on any number of factors. Here, time is in the horizontal direction in units of OFDM symbols; and frequency is in the vertical direction in units of subcarriers or tones.

[0100] Resource grid 404 can be used to schematically represent the time-frequency resources for a given antenna port. That is, in a MIMO implementation with multiple antenna ports available, there may be corresponding multiple resource grids 404 available for communication. Resource grid 404 is divided into multiple resource elements (REs) 406. An RE (which is 1 subcarrier x 1 symbol) is the smallest discrete portion of the time-frequency grid and contains a single complex value representing data from a physical channel or signal. Depending on the modulation utilized in a particular implementation, each RE may represent one or more information bits. In some examples, a block of REs may be referred to as a physical resource block (PRB) or more simply as a resource block (RB) 408, which contains any suitable number of contiguous subcarriers in the frequency domain. In one example, an RB may include 12 subcarriers, independent of the parameter design used. In some examples, depending on the parameter design, an RB may include any suitable number of contiguous OFDM symbols in the time domain. Within this disclosure, it is assumed that a single RB (such as RB 408) corresponds entirely to a single communication direction (transmission or reception for a given device).

[0101] A UE typically utilizes only a subset of the resource grid 404. An RB may be the smallest unit of resources that may be allocated to a UE. Thus, the more RBs scheduled for a UE and the higher the modulation scheme selected for the air interface, the higher the data rate for the UE.

[0102] In this illustration, RB 408 is shown as occupying less than the entire bandwidth of subframe 402, with some subcarriers illustrated above and below RB 408. In a given implementation, subframe 402 may have a bandwidth corresponding to any number of one or more RBs 408. Furthermore, in this illustration, RB 408 is shown as occupying less than the entire duration of subframe 402, but this is merely one possible example.

[0103] Each subframe 402 (e.g., a 1 ms subframe) may include one or more adjacent time slots. Figure 4 In the example shown in FIG, a subframe 402 includes four time slots 410. In some examples, a time slot can be defined according to a specified number of OFDM symbols with a given cyclic prefix (CP) length. For example, a time slot can include 7 or 14 OFDM symbols with a nominal CP. Additional examples may include mini-slots with shorter durations (e.g., 1, 2, 4, or 7 OFDM symbols). In some cases, these mini-slots can be transmitted using resources scheduled for an ongoing time slot transmission for the same or a different UE.

[0104] An expanded view of one of the time slots 410 illustrates that the time slot 410 includes a control region 412 and a data region 414. Generally speaking, the control region 412 may carry a control channel (e.g., PDCCH), while the data region 414 may carry a data channel (e.g., PDSCH or PUSCH). Of course, a time slot may include all DL, all UL, or at least one DL portion and at least one UL portion. Figure 4 The simple structure illustrated in is merely exemplary in nature and different slot structures may be utilized and may include one or more of each of the control region and the data region.

[0105] Although not in Figure 4 Although not illustrated in FIG, each RE 406 within an RB 408 may be scheduled to carry one or more physical channels, including a control channel, a shared channel, a data channel, etc. Other REs 406 within an RB 408 may also carry pilot or reference signals. These pilot or reference signals may be used by a receiving device to perform channel estimation for the corresponding channel, which may enable coherent demodulation / detection of the control and / or data channels within the RB 408.

[0106] In a DL transmission, a transmitting device (e.g., a scheduling entity 108) may allocate one or more REs 406 (e.g., within a control region 412) to carry DL control information 114 to one or more scheduled entities 106. The DL control information 114 includes one or more DL control channels, such as a physical broadcast channel (PBCH), a physical downlink control channel (PDCCH), and the like, which generally carry information originating from higher layers. Additionally, each DL RE may be allocated to carry DL physical signals, which generally do not carry information originating from higher layers. These DL physical signals may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a demodulation reference signal (DM-RS), a phase tracking reference signal (PT-RS), a channel state information reference signal (CSI-RS), and the like.

[0107] Synchronization signals PSS and SSS (collectively referred to as SS), and in some examples, PBCH, may be transmitted in an SS block, which includes four consecutive OFDM symbols numbered in ascending order from 0 to 3 via a time index. In the frequency domain, an SS block may be spread across 240 contiguous subcarriers, where the subcarriers are numbered in ascending order from 0 to 239 via a frequency index. Of course, the present disclosure is not limited to this particular SS block configuration. Other non-limiting examples within the scope of the present disclosure may utilize more or less than two synchronization signals; may include one or more supplemental channels in addition to the PBCH; may omit the PBCH; and / or may use non-consecutive symbols for an SS block.

[0108] The PDCCH may carry downlink control information (DCI) for one or more UEs in a cell. This may include, but is not limited to, power control commands, scheduling information, grants, and / or RE assignments for DL and UL transmissions.

[0109] In an UL transmission, a transmitting device (e.g., the scheduled entity 106) may utilize one or more REs 406 to carry UL control information (UCI) 118. The UCI may originate from higher layers via one or more UL control channels (such as the physical uplink control channel (PUCCH), the physical random access channel (PRACH), etc.) to the scheduling entity 108. Furthermore, each UL RE may carry UL physical signals (which generally do not carry information originating from higher layers), such as a demodulation reference signal (DM-RS), a phase tracking reference signal (PT-RS), a sounding reference signal (SRS), etc. In some examples, the control information 118 may include a scheduling request (SR), i.e., a request for the scheduling entity 108 to schedule an uplink transmission. Here, in response to the SR transmitted on the control channel 118, the scheduling entity 108 may transmit downlink control information 114, which may schedule resources for uplink packet transmission.

[0110] The UL control information may also include hybrid automatic repeat request (HARQ) feedback (such as an acknowledgment (ACK) or negative acknowledgment (NACK)), channel state information (CSI), or any other suitable UL control information. HARQ is a technology well known to those skilled in the art, wherein the integrity of packet transmissions may be verified on the receiving side for accuracy, for example, using any suitable integrity check mechanism (such as a checksum or cyclic redundancy check (CRC)). If the integrity of the transmission is confirmed, an ACK may be transmitted, while if it is not confirmed, a NACK may be transmitted. In response to a NACK, the transmitting device may send a HARQ retransmission, which may enable catch-up combining, incremental redundancy, and the like.

[0111] In addition to control information, one or more REs 406 (e.g., within the data region 414) may also be allocated for user data or traffic data. Such traffic may be carried on one or more traffic channels, such as the physical downlink shared channel (PDSCH) for DL transmissions or the physical uplink shared channel (PUSCH) for UL transmissions.

[0112] To enable a UE to gain initial access to a cell, the RAN may provide system information (SI) that characterizes the cell. This system information may be provided using minimum system information (MSI) and other system information (OSI). MSI may be broadcast periodically on a cell to provide the minimum information required for initial cell access and to obtain any OSI that may be broadcast periodically or sent on demand. In some examples, MSI may be provided on two different downlink channels. For example, the PBCH may carry a master information block (MIB), while the PDSCH may carry system information block type 1 (SIB1). In the art, SIB1 may be referred to as remaining minimum system information (RMSI).

[0113] OSI may include any SI not broadcast in MSI. In some examples, PDSCH may carry multiple SIBs, not limited to SIB1 discussed above. Here, OSI may be provided in these SIBs (e.g., SIB2 and above).

[0114] The above description and Figure 1 and 4 The channels or carriers illustrated in the figure are not necessarily all channels or carriers that can be utilized between the scheduling entity 108 and the scheduled entity 106, and one of ordinary skill in the art will recognize that other channels or carriers can be utilized in addition to those channels or carriers illustrated, such as other traffic, control, and feedback channels.

[0115] These physical channels are typically multiplexed and mapped onto transport channels for processing by the Medium Access Control (MAC) layer. Transport channels carry blocks of information, referred to as transport blocks (TBs). The transport block size (TBS), which may correspond to the number of information bits, may be a controlled parameter based on the modulation and coding scheme (MCS) and the number of RBs in a given transmission.

[0116] In OFDM, in order to maintain the orthogonality of the subcarriers or frequency tones, the subcarrier spacing may be equal to the inverse of the symbol period. The parameter design of an OFDM waveform refers to its specific subcarrier spacing and cyclic prefix (CP) overhead. Scalable parameter design refers to the ability of the network to select different subcarrier spacings and, accordingly, select the corresponding symbol duration (including CP length) for each spacing. With scalable parameter design, the nominal subcarrier spacing (SCS) can be scaled up or down by integer multiples. In this way, regardless of the CP overhead and the selected SCS, the symbol boundaries can be aligned at certain common multiples of each symbol (e.g., at the boundaries of each 1ms subframe). The range of SCSs may include any suitable SCS. For example, a scalable parameter design may support an SCS ranging from 15kHz to 480kHz.

[0117] To illustrate this concept of scalable parameter design, Figure 5A first RB 502 having a nominal parameter design and a second RB 504 having a scaled parameter design are shown. As an example, the first RB 502 may have a 'nominal' subcarrier spacing (SCS) of 30 kHz. n ) and a 'nominal' symbol duration n of 333 μs. Here, in the second RB 504, the scaled parameter design includes twice the nominal SCS or 2×SCS n =60kHz scaled SCS. Because this provides twice the bandwidth per symbol, this results in a shortened symbol duration to carry the same information. Thus, in the second RB 504, the scaled parameter design includes a scaled symbol duration of half the nominal symbol duration or (symbol duration n) ÷ 2 = 167μs.

[0118] Figure 6 is a block diagram illustrating an example of a hardware implementation of a scheduling entity 600 employing a processing system 614. For example, the scheduling entity 600 may be as in Figure 1 、 2 In another example, the scheduling entity 600 may be a user equipment (UE) as illustrated in any one or more of , and / or 3. Figure 1 、 2 , and / or the base station described in any one or more of 3.

[0119] The scheduling entity 600 can be implemented using a processing system 614 including one or more processors 604. Examples of processor 604 include a microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionalities described throughout this disclosure. In various examples, the scheduling entity 600 can be configured to perform any one or more of the functions described herein.

[0120] In this example, processing system 614 can be implemented using a bus architecture generally represented by bus 602. Depending on the specific application and overall design constraints of processing system 602, bus 614 may include any number of interconnecting buses and bridges. Bus 602 communicatively couples various circuits including one or more processors (generally represented by processor 604), memory 605, and computer-readable media (generally represented by computer-readable media 606). Bus 602 may also link various other circuits, such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and will not be described further. Bus interface 608 provides an interface between bus 602 and transceiver 610. Transceiver 610 provides a communication interface or means for communicating with various other equipment over a transmission medium. Depending on the characteristics of the equipment, a user interface 612 (e.g., a keypad, display, speaker, microphone, joystick) may also be provided. Of course, such a user interface 612 is optional and may be omitted in some examples (such as a base station).

[0121] The processor 604 is responsible for managing the bus 602 and general processing, including the execution of software stored on the computer-readable medium 606. The software, when executed by the processor 604, causes the processing system 614 to perform the various functions described below for any particular implementation. The computer-readable medium 606 and memory 605 may also be used to store data that is manipulated by the processor 604 when executing the software.

[0122] One or more processors 604 in the processing system can execute software. Software should be broadly construed to mean instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description languages, or other terms. The software can reside on a computer-readable medium 606. The computer-readable medium 606 can be a non-transitory computer-readable medium. By way of example, non-transitory computer-readable media include magnetic storage devices (e.g., hard disks, floppy disks, magnetic tapes), optical disks (e.g., compact discs (CDs) or digital versatile discs (DVDs)), smart cards, flash memory devices (e.g., card, stick, or key-type drives), random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, removable disks, and any other suitable medium for storing software and / or instructions that can be accessed and read by a computer. Computer-readable medium 606 can reside in processing system 614, external to processing system 614, or distributed across multiple entities including processing system 614. Computer-readable medium 606 can be embodied in a computer program product. By way of example, a computer program product can include a computer-readable medium in packaging materials. Those skilled in the art will recognize how to best implement the described functionality presented throughout this disclosure depending on the specific application and the overall design constraints imposed on the overall system.

[0123] Figure 7 is a conceptual diagram illustrating an example of a hardware implementation of an exemplary scheduled entity 700 employing a processing system 714. According to various aspects of the present disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system 704 including one or more processors 714. For example, the scheduled entity 700 may be as in Figure 1 、 2 , and / or the user equipment (UE) illustrated in any one or more of 3.

[0124] The processing system 714 can be used with Figure 6 The processing system 614 is substantially the same as that described in the preceding paragraph, including a bus interface 708, a bus 702, a memory 705, a processor 704, and a computer readable medium 706. In addition, the scheduled entity 700 may include the same processing system 614 as described above in the preceding paragraph. Figure 6 The user interface 712 and transceiver 710 are substantially similar to those described in .

[0125] In 5G NR, carrier aggregation (CA) is supported. CA refers to the concatenation of multiple component carriers (CCs) to provide increased bandwidth. Such 5G networks can provide aggregation of sub-6 GHz carriers, carriers above 6 GHz, mmWave carriers, etc., all controlled by a single integrated MAC layer. Aggregated CCs can be contiguous or non-contiguous to each other, and they can be inter-band or intra-band. In addition, aggregated CCs can be designed using different parameters, for example, with different subcarrier spacing (SCS), time slot lengths, etc. In some examples, one of these CCs may be referred to as a primary cell (PCell), and one or more other CCs may be referred to as secondary cells (SCells).

[0126] Example beam failure detection and recovery

[0127] Aspects of the present disclosure provide techniques for detecting and recovering from beam failures. As discussed in greater detail herein, detecting and recovering from beam failures may be based on cell restriction rules that restrict the cells from which beam failure recovery response messages are received.

[0128] For downlink transmissions from the gNB to the UE, beamforming or spatial filtering can be utilized. Beamforming generally refers to directional signal transmission or reception. For beamformed transmissions, the amplitude and phase of each antenna in an antenna array can be precoded or controlled to create a desired (e.g., directional) pattern of constructive and destructive interference in the wavefront. A beam can be formed by, but is not limited to, an antenna, an antenna port, an antenna element, an antenna group, a group of antenna ports, or a group of antenna elements. Alternatively, a beam can be formed by a reference signal resource. Beamforming is equivalent to spatial filtering, which allows electromagnetic (EM) radiation to be transmitted.

[0129] The beam failure detection and recovery procedures allow beam switching to be performed when a beam failure event occurs. Generally speaking, a beam failure may correspond to a condition in which the beam quality drops to an unacceptably low level. In one example, the UE may consider that a beam failure instance has occurred when the measured quality of the downlink reference signal drops below a given threshold quality metric. In some examples, the UE may utilize measurements of the reference signal received power (RSRP), reference signal strength indicator (RSSI), or other signal quality metrics (and corresponding thresholds) corresponding to the received CSI-RS or SS blocks to determine that a beam failure event has occurred. Once the UE detects a threshold number of consecutive beam failure events, the UE may declare a beam failure and, accordingly, initiate a beam failure recovery (BFR) procedure, as discussed in more detail below.

[0130] Figure 8Illustrated are example operations 800 that may be performed by a user equipment (UE) to perform a BFR procedure based on received cell restriction rules in accordance with certain aspects described herein. As illustrated, operations 800 may begin at block 802, where the UE detects the occurrence of a threshold number of beam failures for connections between the UE and a set of cells.

[0131] At block 804, the UE identifies candidate beams for restoring connectivity between the UE and the set of cells in response to detecting occurrence of the threshold number of beam failures.

[0132] At block 806, the UE transmits a beam failure recovery (BFR) request to one or more cells in the set of cells, the beam failure recovery (BFR) request including an identification of the candidate beam.

[0133] The UE receives a BFR response from a cell in the set of cells in response to transmitting the BFR request, at block 808. The BFR response is generally received according to restriction rules, as discussed in greater detail herein.

[0134] At block 810, the UE continues communications with the set of cells based on the BFR response.

[0135] Figure 9 Illustrated are example operations 900 that may be performed by a network entity to perform a BFR procedure based on receiving cell restriction rules in accordance with certain aspects described herein. As illustrated, operations 900 may begin at block 902, where the network entity receives a beam failure recovery (BFR) request from a user equipment (UE), the beam failure recovery (BFR) request including an identification of a candidate beam.

[0136] At block 904, the network entity generates a BFR response based on the identified candidate beams.

[0137] At block 906, the network entity transmits a BFR response to the UE based on the restriction rules.

[0138] At block 908, the network entity communicates with the UE based on the identified candidate beam.

[0139] In general, to perform a BFR procedure, a UE may search for new candidate beams for restoring connectivity. When searching for new beams for restoring connectivity between a network entity and the UE, the UE may measure the quality of one or more reference signals (e.g., RSRP, RSSI, etc.) on a given set of candidate beams. For example, the UE may attempt to measure the beams on which each cell in the wireless communication network transmits synchronization signal blocks in a synchronization signal burst. If the measured quality of the beam is above a threshold quality metric, the beam is considered to be a beam on which connectivity can be restored. In some aspects, if multiple beams have a measured quality exceeding the threshold quality metric, the UE may select the beam with the highest measured quality as a candidate beam.

[0140] Once the UE identifies a candidate beam, it can trigger the transmission of a BFR request, notifying the gNB that the UE has detected a beam failure. The BFR request message may include information identifying the candidate beam found in the UE's candidate beam search. In some examples, the UE can transmit the BFR request using a random access procedure. A random access procedure is a procedure in which the UE transmits a random access preamble and a payload (msgA). If the gNB detects the random access preamble and decodes the payload, it responds by transmitting a random access response (RAR or msgB).

[0141] In this example, corresponding to the BFR procedure, the payload of the UE's random access message (msgA) may include information identifying the candidate beams found in the UE's candidate beam search. For example, each candidate beam may be associated with a specific random access preamble configuration, so that the gNB can receive the candidate beam identified by the UE by detecting the specific random access preamble configuration. In some examples, the payload of the UE's random access message may be referred to as a "step 2 MAC CE." Here, step 2 may refer to a series of steps in the UE's BFR procedure. Additionally, the random access response transmitted by the gNB may be referred to as a BFR response. Here, the SCell BFR response includes an uplink grant for a new transmission with the same HARQ process ID as the step 2 MAC CE.

[0142] Generally speaking, after K symbols after receiving the BFR response from the secondary cell (SCell), the beams of all control resource sets (CORESETs) in the failed SCell will be reset to the new beams reported in step 2 MAC CE. Thus, in each SCell, if there is a beam failure, the UE may transmit beam candidates to the gNB via a BFR request message (step 2 MAC CE), and the gNB may transmit a BFR response in response to receiving the BFR request message. After receiving the BFR response, the UE waits for K symbols. After waiting K symbols after receiving the BFR response, the UE may apply the identified downlink beams communicated to the gNB (e.g., in the BFR request message) to all CORESETs in the failed SCell. The value of K may take any suitable value according to various aspects of the present disclosure.

[0143] In some aspects, at least for the PDCCH, after receiving the BFR response to the step 2 MAC CE K symbols later, the UE may apply the new beam indicated in the step 2 MAC CE to receive various signals. For example, if the new beam is identified, the UE may apply the new beam for at least downlink reception on the failed SCell. In some aspects, the new beam may be applied for reception by all CORESETs in the failed SCell.

[0144] For example, various actions may be taken after waiting K symbols based on the parameter designs (or subcarrier spacing (SCS)) of the failed cell and the cell on which the BFR response was received. For example, assume that a UE reports a beam failure on a first SCell. The UE may subsequently receive a BFR response on a second SCell. However, the first and second SCells may have different parameter designs and, accordingly, different symbol lengths. The amount of time corresponding to the K-symbol wait period may therefore differ depending on whether the K-symbol wait period is measured based on the parameter designs (or subcarrier spacing) of the first or second SCell.

[0145] To resolve ambiguity regarding the duration of the K symbol waiting period, the UE may apply appropriate restriction rules related to the BFR response. As described below, various such restriction rules may be applied within the scope of the present disclosure.

[0146] For example, the UE may not apply SCell restrictions, allowing the BFR response to be sent on any SCell. In this example, if the UE reports a beam failure corresponding to the first SCell, the BFR response can be received on any SCell, not just the first SCell. In this example, the UE may determine the length of time corresponding to "K symbols" based on the parameter design of the SCell receiving the BFR response, the parameter design of the failed SCell, or the parameter design of the SCell with the larger or smaller parameter design of the two SCells. In other words, the rule regarding which parameter design corresponds to K symbols may be a fixed value agreed upon in advance between the UE and the network for the UE to use in this scenario.

[0147] In another example, the UE may restrict the BFR response so that it must be received on an SCell with the same parameter design (e.g., the same SCS) as the failed SCell. In this example, if no such SCell with the same parameter design as the failed SCell exists, the gNB may simply forgo transmitting the BFR response. Here, the UE may infer that the time corresponding to K symbols has elapsed based on the parameter design of the failed SCell and, after an appropriate amount of time has elapsed, simply change the beam to the selected candidate beam identified by the UE in the BFR request message. The UE may utilize a local timer started upon transmission of the BFR request message, and if the timer expires before receiving a BFR response from an SCell with the same parameter design as the failed SCell, the UE may set its beam as a candidate beam. That is, receiving a BFR response from an SCell may cause the timer to stop. Upon expiration of the timer (i.e., indicating that no BFR response was received from the SCell), the UE may set its beam as a candidate beam and communicate with one or more cells using the candidate beam.

[0148] In another example, the UE may restrict the BFR response so that it must be received on the failed SCell. In this case, the UE may need to set at least all CORESET beams on the failed SCell to the reported new candidate beams immediately after the UE transmits the step 2 MAC CE. Furthermore, the gNB may transmit the BFR response on the failed SCell using the reported new candidate beams. The UE changes to the new beam K symbols after receiving the BFR response, depending on the symbol length of the failed SCell.

[0149] In yet another example, the UE may restrict the BFR response so that it must be received on a cell with a different parameter design (e.g., a different SCS) than the failed SCell. In this case, the reference for determining the time length of K symbols may correspond to the symbol duration of the failed SCell, or in another example, may correspond to the symbol duration of the SCell on which the BFR response is received.

[0150] Figure 10 is a call flow diagram illustrating messages exchanged between a user equipment (UE) and one or more cells to handle beam failure based on receiving cell restriction rules in accordance with certain aspects described herein. As illustrated, a UE 1002 may begin at block 1010 by detecting that a threshold number of consecutive beam failure events have occurred. In response to detecting that the threshold number of consecutive beam failure events have occurred at block 1010, at block 1012, the UE identifies candidate beams for subsequent communication. The candidate beams may be, for example, based on a count of beams received in each of a plurality of beam directions from a network entity (e.g., one of a plurality of cells serving the UE, such as Figure 10 The UE may identify a candidate beam based on a measurement of signaling received by the UE (e.g., cell 1004 or cell 1006, as illustrated in FIG. 1 ). The signaling may be, for example, synchronization signal blocks transmitted in synchronization signal bursts in different beam directions. At block 1012, the UE may identify a candidate beam based on a comparison of measured signal quality (e.g., RSRP, RSSI, etc.) with a threshold signal quality metric. If the measured signal quality of the beam exceeds the threshold signal quality metric, the UE may identify the beam as a candidate beam. If multiple beams have measured signal qualities exceeding the threshold signal quality metric, the UE may select the beam associated with the highest measured signal quality as a candidate beam.

[0151] After identifying the candidate beams at block 1012, the UE 1002 transmits a BFR request 1014 to the cell 1004. In some aspects, the cell 1004 may be a secondary cell (SCell) in a cluster of cells serving the UE 1002. The BFR request 1014 generally includes the identification of the candidate beams. In response, the cell 1004 transmits a BFR response 1016 to the UE 1002. The UE 1002 may wait for K symbol intervals 1018 to communicate 1020 using the candidate beams. As discussed, the K symbol intervals 1018 may be the number of symbols since the BFR response 1016 was received and may have a duration based on the subcarrier spacing configuration (or parameter design) of the cell on which the beam failure was detected or one of the cells from which the BFR response was received.

[0152] Figure 11 Illustrated may include operations configured to perform the techniques disclosed herein (such as, Figure 8 1 and 1 . The communication device 1100 includes various components (e.g., corresponding to means-plus-function components) that perform the operations illustrated in FIG. 1 and 1 . The communication device 1100 includes a processing system 1108 coupled to a transceiver 1102 (e.g., a transmitter and / or a receiver). The transceiver 1108 is configured to transmit and receive signals for the communication device 1100 (such as the various signals described herein) via an antenna 1110. The processing system 1102 can be configured to perform processing functions for the communication device 1100, including processing signals received and / or to be transmitted by the communication device 1100.

[0153] The processing system 1102 includes a processor 1104 coupled to a computer readable medium / memory 1112 via a bus 1106. In some aspects, the computer readable medium / memory 1112 is configured to store data that, when executed by the processor 1104, causes the processor 1104 to execute Figure 8 Instructions (e.g., computer-executable code) for performing the operations illustrated in the or other operations discussed herein for various techniques for reporting and responding to beam failure events based on receiving cell restriction rules. In certain aspects, the computer-readable medium / memory 1112 stores code 1114 for detecting the occurrence of a threshold number of beam failures for a connection between a UE and a set of cells; code 1116 for identifying candidate beams for restoring the connection between the UE and the set of cells in response to detecting the occurrence of the threshold number of beam failures; code 1118 for transmitting a beam failure recovery (BFR) request to one or more cells in the set of cells, the beam failure recovery (BFR) request including an identification of the candidate beams; code 1120 for receiving a BFR response from a cell in the set of cells in response to transmitting the BFR request; and code 1122 for continuing communication with the set of cells based on the BFR response. In certain aspects, the processor 1104 has circuitry configured to implement the code stored in the computer-readable medium / memory 1112. Processor 1104 includes circuitry 1124 for detecting the occurrence of a threshold number of beam failures for a connection between a UE and a set of cells; circuitry 1126 for identifying a candidate beam for restoring the connection between the UE and the set of cells in response to detecting the occurrence of the threshold number of beam failures; circuitry 1128 for transmitting a beam failure recovery (BFR) request to one or more cells in the set of cells, the beam failure recovery (BFR) request including an identification of the candidate beam; circuitry 1130 for receiving a BFR response from a cell in the set of cells in response to transmitting the BFR request; and circuitry 1132 for continuing communication with the set of cells based on the BFR response.

[0154] Figure 12 Illustrated are operations that may include being configured to perform the techniques disclosed herein (such as Figure 9 12. The communication device 1200 includes various components (e.g., corresponding to means-plus-function components) for performing the operations illustrated in FIG. 12. The communication device 1200 includes a processing system 1202 coupled to a transceiver 1208 (e.g., a transmitter and / or receiver). The transceiver 1208 is configured to transmit and receive signals for the communication device 1200 (such as the various signals described herein) via an antenna 1210. The processing system 1202 may be configured to perform processing functions for the communication device 1200, including processing signals received and / or to be transmitted by the communication device 1200.

[0155] The processing system 1202 includes a processor 1204 coupled to a computer readable medium / memory 1212 via a bus 1206. In some aspects, the computer readable medium / memory 1212 is configured to store data that, when executed by the processor 1204, causes the processor 1204 to execute Figure 9 Instructions (e.g., computer-executable code) for performing the operations illustrated in the or other operations discussed herein for reporting beam failure events based on receiving cell restriction rules and responding to beam failure events. In certain aspects, the computer-readable medium / memory 1212 stores code 1214 for receiving a beam failure recovery (BFR) request from a user equipment (UE), the beam failure recovery (BFR) request including an identification of a candidate beam; code 1216 for generating a BFR response based on the identified candidate beam; code 1218 for transmitting the BFR response to the UE based on the restriction rules; and code 1220 for communicating with the UE based on the identified candidate beam. In certain aspects, the processor 1214 has circuitry configured to implement the code stored in the computer-readable medium / memory 1212. Processor 1214 includes circuitry 1222 for receiving a beam failure recovery (BFR) request from a user equipment (UE), the beam failure recovery (BFR) request including an identification of a candidate beam; circuitry 1224 for generating a BFR response based on the identified candidate beam; circuitry 1226 for transmitting the BFR response to the UE based on a restriction rule; and circuitry 1228 for communicating with the UE based on the identified candidate beam.

[0156] Additional considerations

[0157] The techniques described herein may be used for various wireless communication technologies such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), Advanced LTE (LTE-A), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, and others. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). cdma2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2). NR is an emerging wireless communication technology under development.

[0158] In 3GPP, the term "cell" can refer to the coverage area of a Node B (NB) and / or the NB subsystem serving that coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and base station (BS), next-generation Node B (gNB or g-Node B), access point (AP), distributed unit (DU), carrier, or transmit reception point (TRP) can be used interchangeably. A BS can provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell can cover a relatively large geographic area (e.g., several kilometers in radius) and can allow unrestricted access by UEs with service subscriptions. A pico cell can cover a relatively small geographic area and can allow unrestricted access by UEs with service subscriptions. A femto cell can cover a relatively small geographic area (e.g., a residence) and can allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in a residence, etc.). A BS for a macro cell can be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS.

[0159] A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a customer premises equipment (CPE), a cellular phone, a smartphone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor / device, a wearable device (such as a smart watch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet, etc.)), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicle component or sensor, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node can provide connectivity to or to a network (e.g., a wide area network (such as the Internet) or a cellular network) via, for example, a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0160] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication between some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, the subordinate entities utilize the resources allocated by the scheduling entity. The base station is not the only entity that can be used as a scheduling entity. In some examples, a UE may act as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In the mesh network example, UEs may communicate directly with each other in addition to communicating with the scheduling entity.

[0161] Each method disclosed herein includes one or more steps or actions for implementing the method. These method steps and / or actions may be interchangeable with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of the specific steps and / or actions may be modified without departing from the scope of the claims.

[0162] As used herein, a phrase referring to "at least one" of a list of items refers to any combination of those items, including individual members. By way of example, "at least one of a, b, or c" is intended to encompass: a, b, c, ab, ac, bc, and abc, as well as any combination with multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0163] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, database, or another data structure), ascertaining, and the like. Furthermore, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Furthermore, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0164] The preceding description is provided to enable anyone skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the universal principles defined herein may be applied to other aspects. Accordingly, the claims are not intended to be limited to the aspects shown herein, but rather should be granted the full scope consistent with the claim language, wherein singular references to elements are not intended to mean "one and only one" (unless specifically stated otherwise) but rather "one or more." Unless specifically stated otherwise, the term "some" refers to one or more. All structural and functional equivalents of the elements described throughout this disclosure, now or hereafter known to those of ordinary skill in the art, are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims. No element of a claim should be interpreted under 35 U.S.C. §112(f) unless the element is explicitly recited using the phrase "means for..." or, in the case of a method claim, the element is recited using the phrase "step for..."

[0165] The various operations of the methods described above may be performed by any suitable device capable of performing the corresponding functions. These devices may include various hardware and / or software components and / or modules, including but not limited to circuits, digital signal processors (DSPs), application specific integrated circuits (ASICs), or processors (e.g., general-purpose processors or specially programmed processors). Generally, where there are operations illustrated in the figures, these operations may have corresponding counterpart means-plus-function components with similar numbering.

[0166] The various illustrative logical blocks, modules, and circuits described in connection with the present disclosure may be implemented or executed with a general-purpose processor, a DSP, an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD), 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 the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0167] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus may include any number of interconnecting buses and bridges. The bus may link together various circuits including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter, etc., to the processing system via the bus. The network adapter may be used to implement signal processing functions at the PHY layer. In a user terminal (see Figure 1 ), a user interface (e.g., a keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art and will not be described further. The processor may be implemented using one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry capable of executing software. Those skilled in the art will recognize how to best implement the functionality described with respect to the processing system, depending on the specific application and the overall design constraints imposed on the overall system.

[0168] If implemented in software, each function may be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media includes both computer storage media and communication media, including any media that facilitates the transfer of a computer program from one location to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. A computer-readable storage medium may be coupled to the processor so that the processor can read and write information from / to the storage medium. In an alternative embodiment, the storage medium may be integrated into the processor. As an example, the machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon that is separate from the wireless node, all of which may be accessed by the processor via a bus interface. Alternatively or additionally, the machine-readable medium or any portion thereof may be integrated into the processor, such as a cache and / or general register file. As examples, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be embodied in a computer program product.

[0169] A software module may include a single instruction or many instructions and may be distributed across several different code segments, between different programs, and across multiple storage media. A computer-readable medium may include several software modules. These software modules include instructions that, when executed by a device (such as a processor), cause a processing system to perform various functions. These software modules may include a transmitting module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. As an example, when a triggering event occurs, a software module may be loaded from a hard drive into RAM. During the execution of the software module, the processor may load some instructions into a cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When describing the functionality of a software module below, it will be understood that such functionality is implemented by the processor when the processor executes instructions from the software module.

[0170] Likewise, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies (such as infrared (IR), radio, and microwave), then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies (such as infrared, radio, and microwave) are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0171] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include a computer-readable medium having instructions stored (and / or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein, such as for performing the operations described herein and in Figure 8 and / or Figure 9 Instructions for the operations explained in .

[0172] In addition, it should be appreciated that the modules and / or other appropriate means for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by the user terminal and / or base station where applicable. For example, such a device can be coupled to a server to facilitate the transfer of the means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.) so that once the storage device is coupled to or provided to the user terminal and / or base station, the device can obtain the various methods. In addition, any other suitable technology suitable for providing the methods and techniques described herein to a device can be utilized.

[0173] It will be understood that the claims are not limited to the precise configuration and components illustrated above. Various changes, substitutions and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. A method for wireless communication by a user equipment (UE), comprising: detecting occurrence of a threshold number of beam failures of a connection between the UE and a first cell in a set of cells; identifying, in response to detecting occurrence of the threshold number of beam failures, a candidate beam for restoring a connection between the UE and the first cell in the set of cells; transmitting a beam failure recovery (BFR) request to one or more second cells in the set of cells other than the first cell, the BFR request including an identification of the candidate beam; receiving a BFR response from the one or more second cells in the set of cells other than the first cell in response to transmitting the BFR request, wherein the BFR response is received according to a restriction rule, wherein the restriction rule allows receipt of the BFR response from any cell in the set of cells other than the first cell, and wherein the restriction rule further defines a gap between receiving the BFR response and continuing communications with the set of cells based on a parameter design of one of: a cell from which the BFR response was received or a failed cell on which a beam failure was detected; and Communication with the set of cells is continued based on the BFR response.

2. The method of claim 1 , wherein the gap comprises a number of symbols between receiving the BFR response and continuing communications with the set of cells, the number of symbols being a fixed value.

3. The method of claim 1 , wherein the gap comprises a number of symbols between receiving the BFR response and continuing communications with the set of cells, the number of symbols being based on the lesser of: a subcarrier spacing associated with the failed cell and a subcarrier spacing associated with the cell from which the BFR response was received.

4. The method of claim 1 , wherein the gap comprises a number of symbols between receiving the BFR response and continuing communications with the set of cells, the number of symbols being based on the greater of: a subcarrier spacing associated with the failed cell and a subcarrier spacing associated with the cell from which the BFR response was received.

5. The method of claim 1 , wherein the restriction rule restricts receiving the BFR response from cells having a different subcarrier spacing than the failed cell on which the beam failure was detected.

6. The method of claim 5, further comprising: starting a timer upon transmitting the BFR request to the one or more second cells in the set of cells; as well as Upon expiration of the timer, communication with the set of cells is continued based on the identified candidate beam.

7. The method of claim 1, wherein the restriction rule restricts receiving the BFR response from cells other than the failed cell on which the beam failure was detected.

8. The method of claim 7, further comprising: Upon transmitting the BFR request, a beam for each control resource set (CORESET) is reset to the identified candidate beam, wherein the BFR response is received from the failed cell on the identified candidate beam.

9. The method of claim 1, wherein the restriction rule restricts receiving the BFR response from cells having the same subcarrier spacing as the failed cell on which the beam failure was detected.

10. An apparatus for wireless communication by a user equipment (UE), comprising: a memory having instructions; as well as One or more processors, the one or more processors being individually or collectively configured to read the instructions and cause the UE to: detecting occurrence of a threshold number of beam failures of a connection between the UE and a first cell in a set of cells; In response to detecting the occurrence of the threshold number of beam failures, identifying a method for recovering the UE candidate beams for a connection with the first cell in the set of cells; transmitting a beam failure recovery (BFR) request to one or more second cells in the set of cells other than the first cell, the BFR request including an identification of the candidate beam; receiving a BFR response from the one or more second cells in the set of cells other than the first cell in response to transmitting the BFR request, wherein the BFR response is received according to a restriction rule, wherein the restriction rule allows receipt of the BFR response from any cell in the set of cells other than the first cell, and wherein the restriction rule further defines a gap between receiving the BFR response and continuing communications with the set of cells based on a parameter design of one of: a cell from which the BFR response was received or a failed cell on which a beam failure was detected; and Communication with the set of cells is continued based on the BFR response.

11. The apparatus of claim 10, wherein the gap comprises a number of symbols between receiving the BFR response and continuing communications with the set of cells, the number of symbols being a fixed value.

12. The apparatus of claim 10 , wherein the gap comprises a number of symbols between receiving the BFR response and continuing communications with the set of cells, the number of symbols being based on the smaller of: a subcarrier spacing associated with a failed cell and a subcarrier spacing associated with a cell from which the BFR response was received.

13. The apparatus of claim 10 , wherein the gap comprises a number of symbols between receiving the BFR response and continuing communications with the set of cells, the number of symbols being based on the greater of: a subcarrier spacing associated with a failed cell and a subcarrier spacing associated with a cell from which the BFR response was received.

14. The apparatus of claim 10, wherein the restriction rule restricts receiving the BFR response from a cell having a different subcarrier spacing than the failed cell on which the beam failure was detected.

15. The apparatus of claim 14, wherein the one or more processors are further configured individually or collectively to read the instructions and cause the UE to: starting a timer upon transmitting the BFR request to the one or more second cells in the set of cells; and Upon expiration of the timer, communication with the set of cells is continued based on the identified candidate beam.

16. The apparatus of claim 10, wherein the restriction rule restricts receiving the BFR response from cells other than a failed cell on which a beam failure is detected.

17. The apparatus of claim 16, wherein the one or more processors are further configured individually or collectively to read the instructions and cause the UE to: Upon transmitting the BFR request, a beam for each control resource set (CORESET) is reset to the identified candidate beam, wherein the BFR response is received from the failed cell on the identified candidate beam.

18. The apparatus of claim 10, wherein the restriction rule restricts receiving the BFR response from cells having the same subcarrier spacing as the failed cell on which the beam failure was detected.

19. An apparatus for wireless communication by a user equipment (UE), comprising: means for detecting occurrence of a threshold number of beam failures for a connection between the UE and a first cell in a set of cells; means for identifying, in response to detecting occurrence of the threshold number of beam failures, a candidate beam for restoring a connection between the UE and the first cell in the set of cells; means for transmitting a beam failure recovery (BFR) request to one or more second cells in the set of cells other than the first cell, the BFR request including an identification of the candidate beam; means for receiving a BFR response from the one or more second cells in the set of cells other than the first cell in response to transmitting the BFR request, wherein the BFR response is received according to a restriction rule, wherein the restriction rule allows receipt of the BFR response from any cell in the set of cells other than the first cell, and wherein the restriction rule further defines a gap between receiving the BFR response and continuing communications with the set of cells based on a parameter design of one of: a cell from which the BFR response was received, or a failed cell on which a beam failure was detected; as well as Means for continuing communications with the set of cells based on the BFR response.

20. The apparatus of claim 19, wherein the gap comprises a number of symbols between receiving the BFR response and continuing communications with the set of cells, the number of symbols being based on the smaller of: a subcarrier spacing associated with a failed cell and a subcarrier spacing associated with a cell from which the BFR response was received.

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