Detection of beam failures in a second band based on measurements in a first band

Abstract

Some aspects of the present disclosure provide techniques for beam failure detection in a second band based on measurements in a first band. The method, which may be performed by a user equipment (UE), includes receiving one or more reference signals (RSs) on a first radio frequency band and initiating beam failure recovery on a second radio frequency band based at least in part on the one or more RSs on the first radio frequency band. The UE may measure the one or more RSs on the first radio frequency band and perform beam failure detection (BFD) for the second radio frequency band based at least in part on the one or more measurements of the one or more RSs on the first radio frequency band.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit and priority of U.S. Provisional Patent Application No. 62 / 968,668, filed on January 31, 2020, and claims the priority of U.S. Application No. 17 / 158,656, filed on January 26, 2021, the entire contents of both of which are incorporated herein by reference.

[0003] Aspects of the present disclosure relate to wireless communication, and more particularly, to techniques for beam obstacle detection.

Background Art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephone, video, data, messaging, broadcast, etc. These wireless communication systems may employ multiple - access techniques that can support communication with multiple users by sharing available system resources (such as bandwidth, transmit power, etc.). Examples of such multiple - access systems include, among others, the 3rd Generation Partnership Project (3GPP (registered trademark)) Long Term Evolution (LTE) system, the LTE - Advanced (LTE - A) system, the Code Division Multiple Access (CDMA) system, the Time Division Multiple Access (TDMA) system, the Frequency Division Multiple Access (FDMA) system, the Orthogonal Frequency Division Multiple Access (OFDMA) system, the Single - Carrier Frequency Division Multiple Access (SC - FDMA) system, and the Time Division Synchronous Code Division Multiple Access (TD - SCDMA) system.

[0005] These multiple access technologies are employed in various telecommunications standards to provide a common protocol that enables different wireless devices to communicate at urban, national, regional, and even global levels. New radio (e.g., 5G NR) is an example of an emerging telecommunications standard. NR is a set of extensions to the LTE mobile standard published by 3GPP. NR is designed to better support mobile broadband internet access by improving spectral efficiency, lowering costs, improving service, utilizing new spectrum, and better integrating with other open standards that use OFDMA with cyclic prefixes (CP) on downlink (DL) and uplink (UL). To these purposes, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0006] However, as the demand for mobile broadband access continues to increase, further improvements in NR and LTE technologies are needed. Preferably, these improvements should be applicable to other multiple access technologies and the telecommunications standards that employ them. [Overview of the project] [Means for solving the problem]

[0007] Each of the systems, methods, and devices of this disclosure has several embodiments, and no single embodiment alone embodies its desired attributes. Some features are briefly described here without limiting the scope of this disclosure as expressed in the following claims. After reviewing this description, and especially after reading the section titled “Modes for Carrying Out the Invention,” it will be understood how the features of this disclosure provide advantages, including improved beam fault detection (BFD).

[0008] Some aspects of the subject matter described herein may be implemented in a method for wireless communication by user equipment (UE). This method generally includes the steps of receiving one or more reference signals (RS) on a first radio frequency band and initiating a beam fault recovery procedure on a second radio frequency band, at least in part on the one or more RS received on the first radio frequency band.

[0009] Some aspects of the subject matter described herein may be implemented in a device for wireless communications by a UE. This device generally includes means for receiving one or more RSs on a first radio frequency band, and means for initiating a beam fault recovery procedure on a second radio frequency band, at least in part, based on one or more RSs received on the first radio frequency band.

[0010] Some aspects of the subject matter described herein may be implemented in a device for wireless communications. This device generally includes a memory and at least one processor coupled to the memory. The memory and at least one processor are generally configured to receive one or more RSs on a first radio frequency band and to initiate a beam fault recovery procedure on a second radio frequency band based at least in part on one or more RSs received on the first radio frequency band.

[0011] Some aspects of the subject matter described herein may be implemented in a computer-readable medium recording computer-executable code for wireless communications. This computer-readable medium generally includes code for receiving one or more RSs on a first radio frequency band, and code for initiating a beam fault recovery procedure on a second radio frequency band, at least in part, based on the one or more RSs received on the first radio frequency band.

[0012] Some aspects of the subject matter described herein may be implemented in a method for wireless communication by a UE. The method generally includes the step of measuring one or more RSs on a first radio frequency band. The method generally includes the step of determining a BFD for a second radio frequency band based at least in part on the measurements of one or more RSs on the first radio frequency band.

[0013] Some aspects of the subject matter described herein may be implemented in a method for wireless communication by a base station (BS). The method generally includes the step of transmitting a first one or more RS on a first radio frequency band to a UE. The method generally includes the step of receiving a request from the UE to transmit a second one or more RS on a second radio frequency band in response to the first one or more RS on the first radio frequency band. The method generally includes the step of transmitting a second one or more RS on a second radio frequency band to the UE.

[0014] Some aspects of the subject matter described herein may be implemented in a device for wireless communications. This device generally includes a memory and at least one processor coupled to the memory. The memory and at least one processor are generally configured to measure one or more RSs on a first radio frequency band and to determine a BFD for a second radio frequency band based at least in part on the measurements of one or more RSs on the first radio frequency band.

[0015] Some aspects of the subject matter described herein may be implemented in a device for wireless communications. The device generally includes a memory and at least one processor coupled to the memory. The memory and at least one processor are generally configured to transmit one or more first RSs on a first radio frequency band to a UE, to receive a request from the UE to transmit one or more second RSs on a second radio frequency band in response to the one or more first RSs on the first radio frequency band, and to transmit one or more second RSs on the second radio frequency band to the UE.

[0016] Some aspects of the subject matter described herein may be implemented in a device for wireless communications. This device generally includes means for measuring one or more RSs on a first radio frequency band, and means for determining a BFD for a second radio frequency band based at least in part on the measurements of one or more RSs on the first radio frequency band.

[0017] Some aspects of the subject matter described herein may be implemented in a device for wireless communication. The device generally includes means for transmitting one or more first RSs on a first radio frequency band to a UE; means for receiving a request from the UE to transmit one or more second RSs on a second radio frequency band in response to the one or more first RSs on the first radio frequency band; and means for transmitting one or more second RSs on a second radio frequency band to the UE.

[0018] Some aspects of the subject matter described herein may be implemented in a computer-readable medium recording computer-executable code for wireless communications. This computer-readable medium generally includes a code for measuring one or more RSs on a first radio frequency band, and a code for determining a BFD for a second radio frequency band, at least in part, based on the measurements of one or more RSs on the first radio frequency band.

[0019] Some aspects of the subject matter described herein may be implemented in a computer-readable medium recording computer-executable code for wireless communication. The device generally includes code for transmitting one or more first RSs on a first radio frequency band to a UE; code for receiving a request from the UE to transmit one or more second RSs on a second radio frequency band in response to the first one or more RSs on the first radio frequency band; and code for transmitting one or more second RSs on a second radio frequency band to the UE.

[0020] To achieve the above and related objectives, one or more embodiments shall have features that are fully described below and, in particular, pointed out in the claims. The following description and accompanying drawings shall detail some exemplary features of one or more embodiments. However, these features shall only represent a few of the various ways in which the principles of the various embodiments may be employed.

[0021] To allow for a more detailed understanding of the features of this disclosure, some of which may be described in the drawings, a more specific description of these features may be obtained by referring to the embodiments shown above. However, since this description may extend to other equally effective embodiments, it should be noted that the accompanying drawings should not be considered to represent only some typical embodiments of this disclosure and therefore limit the scope of this disclosure. [Brief explanation of the drawing]

[0022] [Figure 1] This is a block diagram conceptually illustrating an exemplary telecommunications system according to some aspects of the present disclosure. [Figure 2] This is a block diagram conceptually illustrating the design of exemplary base station (BS) and user equipment (UE) according to several aspects of this disclosure. [Figure 3] This figure shows an exemplary frame format for New Radio (NR) according to several aspects of the present disclosure. [Figure 4]A diagram showing an exemplary frequency range according to some aspects of the present disclosure. [Figure 5] A diagram showing an exemplary networked environment in which a prediction model is used for channel estimation according to some aspects of the present disclosure. [Figure 6] A diagram showing an exemplary node in a networked environment in which a prediction model is used for channel estimation for beam obstruction detection according to some aspects of the present disclosure. [Figure 7] A flowchart showing an exemplary operation for wireless communication by a UE according to some aspects of the present disclosure. [Figure 8] A flowchart showing an exemplary operation for wireless communication by a UE according to some aspects of the present disclosure. [Figure 9] A flowchart showing an exemplary operation for wireless communication by a BS according to some aspects of the present disclosure. [Figure 10A] A decision tree diagram showing an exemplary operation for wireless communication by a UE according to some aspects of the present disclosure. [Figure 10B] Another decision tree diagram showing an exemplary operation for wireless communication by a UE according to some aspects of the present disclosure. [[ID=XXX]] [[ID=XXX]] [Figure 11A] A call flow diagram showing exemplary signaling according to some aspects of the present disclosure. [Figure 11B] A call flow diagram showing exemplary signaling according to some aspects of the present disclosure. [Figure 12] A diagram showing a communication device that may include various components configured to perform operations for the techniques disclosed herein according to an aspect of the present disclosure. [Figure 13] A diagram showing a communication device that may include various components configured to perform operations for the techniques disclosed herein according to an aspect of the present disclosure.

Mode for Carrying Out the Invention

[0023] Note: There are some tags like etc. which seem to be some kind of custom identifiers and are kept as they are without further translation as per the instruction. Also, the "XXX" marked lines are just to show the continuity of numbering where some content might be missing in the original for a proper translation understanding. For ease of understanding, the same reference numerals are used to designate identical elements common to the figures where possible. It is intended that elements disclosed in one embodiment may be advantageously utilized in other embodiments without specific specification.

[0024] Aspects of this disclosure provide apparatus, methods, processing systems, and computer-readable media for beam fault detection (BFD) in a second radio frequency band based on measurements in a first radio frequency band. The radio frequency bands used herein may also be referred to as frequency bands or bands.

[0025] In some systems, machine learning (ML) techniques may be used to predict channel characteristics in a second radio frequency band based on measurements in a first radio frequency band. For example, measurements in a first radio frequency band (e.g., the sub-6 GHz band, sometimes called FR1) may be simpler and more power-efficient than performing measurements in a different band (e.g., the millimeter-wave (mmW) band, sometimes called FR2, which can be in the frequency range of 24.25–52.6 GHz). In one example, measurements in the first band may be more efficient than measurements in the second band. For example, measurements in the first band may be more efficient than measurements in the second band due to the hardware characteristics of the UE. Also, the measurement overhead in the second band may be lower by using measurements from the first band.

[0026] In some cases, BFD in the FR2 band may be detected / reported based on reference signal (RS) measurements in the FR1 band (or other bands, such as measurements on FR2 for channel estimation and BFD for FR4). In some cases, a UE may detect beam faults to a second band based on estimates from RS measurements in a first band (e.g., without performing any RS measurements in the second band). For example, a UE may estimate (e.g., predict) the reference signal received power (RSRP) for a serving beam in a second band based on RS measurements in a first band. If the estimated RSRP for the second band is at or above the BFD threshold for the second band, or outside the limits of the BFD threshold for the second band, the UE may determine that there are no beam faults to the second band without further RS ​​measurements in the second band. If the RSRP estimate for a serving beam in the second band is within limits (e.g., approaching the BFD threshold for the second band) or within limits for the number of measurement instances, the UE may request the base station to transmit a BFD RS (e.g., an "on-demand BFD RS") on the second band. The UE may then measure and determine the BFD RS on the second band to determine whether the second band is in a beam-fault condition. In some examples, the request for the RS is transmitted over the physical uplink control channel (PUCCH). If the RSRP is outside the limits and below the BFD threshold for the second band, the UE may determine that the serving beam in the second band is not in a beam-fault condition or is not approaching a beam-fault condition.

[0027] The following description provides an example of a BFD in a second band based on measurements in a first band within a communication system and does not limit the scope, applicability, or examples described in the claims. Modifications may be made to the function and configuration of the elements described without departing from the scope of this disclosure. Various examples may, as appropriate, omit, replace, or add various procedures or components. For example, the methods described may be performed in a different order than described, and various steps may be added, omitted, or combined. Also, features described in some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of embodiments described herein. Furthermore, the scope of this disclosure shall cover apparatus or methods that are practiced using other structures, functions, or structures and functions in addition to, or other than, the various embodiments of this disclosure described herein. It should be understood that any embodiment of this disclosure disclosed herein may be embodied by one or more elements of the claims. The term “exemplary” is used herein to mean “acting as an example, case, or illustration.” Any embodiment described herein as "exemplary" should not necessarily be construed as being more preferable or advantageous than any other embodiment.

[0028] In general, any number of wireless networks can be deployed within a given geographical area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. RATs are sometimes called radio technologies or air interfaces. Frequencies are sometimes called carriers, subcarriers, frequency channels, tones, or subbands. Each frequency may support a single RAT within a given geographical area to avoid interference between wireless networks of different RATs.

[0029] The techniques described herein may be used for a variety of wireless networks and radio technologies. While this specification may use terminology generally associated with 3G, 4G, and / or New Radio (e.g., 5G NR) wireless technologies to describe aspects of the invention, aspects of this disclosure may be applicable to other generation-based communication systems.

[0030] New radio (e.g., 5G NR) can support a variety of wireless communication services, including extended mobile broadband (eMBB) targeting high bandwidth, millimeter wave (mmW) targeting high carrier frequencies, massive machine type communication MTC (mMTC) targeting non-backward compatible MTC techniques, and / or mission-critical services targeting ultra-high reliability low-latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmit time intervals (TTIs) to meet their respective quality of service (QoS) requirements. In addition, these services may coexist within the same subframe.

[0031] NR supports beamforming, and the beam direction may be dynamically configured. MIMO transmission with precoding may also be supported. MIMO configuration in DL can support up to eight transmitting antennas with multilayer DL transmission of up to eight streams and up to two streams per UE. Multilayer transmission with up to two streams per UE may be supported. Aggregation of multiple cells may be supported with up to eight serving cells.

[0032] The electromagnetic spectrum is often subdivided into various classes, bands, channels, etc., based on frequency / wavelength. In 5G NR, two initial operating bands are specified as frequency range designations FR1 (410 MHz to 7.125 GHz) and FR2 (24.25 GHz to 52.6 GHz). Although a portion of FR1 is above 6 GHz, it should be understood that FR1 is often referred to (interchangeably) as the "sub-6 GHz" band in various documents and papers. A similar terminology issue sometimes arises with respect to FR2, which is often referred to (interchangeably) as the "millimeter wave" band in documents and papers, even though it is different from the extremely high frequency (EHF) band (30 GHz to 300 GHz) designated as the "millimeter wave" band by the International Telecommunication Union (ITU).

[0033] The frequencies between FR1 and FR2 are often referred to as midband frequencies. Recent 5G NR research has identified the operating band for these midband frequencies as frequency range designation FR3 (7.125 GHz to 24.25 GHz). The frequency band falling into FR3 can inherit the FR1 and / or FR2 characteristics, and thus the features of FR1 and / or FR2 can be effectively extended to the midband frequencies. In addition, higher frequency bands are currently being considered to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR4a or FR4-1 (52.6 GHz to 71 GHz), FR4 (52.6 GHz to 114.25 GHz), and FR5 (114.25 GHz to 300 GHz). Each of these higher frequency bands falls within the EHF band.

[0034] With the above aspects in mind, please understand that, unless otherwise specified, terms such as "sub-6GHz" used herein may broadly refer to frequencies that may be less than 6GHz, within FR1, or include midband frequencies. Furthermore, please understand that, unless otherwise specified, terms such as "millimeter wave" used herein may broadly refer to frequencies that may include intermediate band frequencies, within FR2, FR4, FR4-a, or FR4-1 and / or FR5, or within the EHF band.

[0035] Figure 1 shows an exemplary wireless communication network 100 in which embodiments of the present disclosure may be implemented. For example, the wireless communication network 100 may be an NR system (e.g., a 5G NR network). As shown in Figure 1, the wireless communication network 100 may communicate with a core network 132. The core network 132 may communicate with one or more base stations (BS) 110a-z (each also referred to individually or collectively as BS110 in this specification), user equipment (UE) 120a-y (each also referred to individually or collectively as UE120 in this specification), and other network entities within the wireless communication network 100 via one or more interfaces. The core network 132 may include one or more core network nodes 134.

[0036] A BS110 can provide communication coverage to a specific geographic area, which may be called a “cell,” and may be fixed or mobile according to the location of the mobile BS110. In some examples, BS110s may be interconnected with each other and / or with one or more other BSs or network nodes (not shown) within the wireless communication network 100 through various types of backhaul interfaces (e.g., direct physical connection, wireless connection, virtual network, etc.) using any suitable transport network. In the example shown in Figure 1, BS110a, 110b, and 110c may be macroBSs for macrocells 102a, 102b, and 102c, respectively. BS110x may be a picoBS for picocell 102x. BS110y and 110z may be femtoBSs for femtocells 102y and 102z, respectively. A BS may support one or more cells.

[0037] BS110 communicates with UE120 within a wireless communication network 100. UE120 (e.g., 120x, 120y, etc.) may be distributed throughout the wireless communication network 100, and each UE120 may be fixed or mobile. The wireless communication network 100 may include relay stations (e.g., relay station 110r), also known as relays, which receive transmissions of data and / or other information from upstream stations (e.g., BS110a or UE120r) and transmit transmissions of data and / or other information to downstream stations (e.g., UE120 or BS110), or relay transmissions between UE120s to facilitate communication between devices. BS110 and UE120 may communicate with each other using beams. As shown in Figure 1, BS110a may communicate with UE120a using a serving beam 101 (e.g., from a set of beams).

[0038] The network controller 130 may communicate with a set of BS110s and may coordinate and control these BS110s (for example, via backhaul). In some embodiments, the network controller 130 may communicate with a core network 132 (for example, a 5G core network (5GC)) which provides various network functions such as access and mobility management, session management, user plane functions, policy control functions, authentication server functions, integrated data management, application functions, network exposure functions, network repository functions, and network slice selection functions.

[0039] According to some embodiments, BS110 and UE120 may be configured for BFD. As shown in Figure 1, BS110a includes a BFD manager 112. As shown in Figure 1, UE120a includes a BFD manager 122. BFD managers 112 and / or BFD managers 122 may, according to embodiments of the present disclosure, be configured for BFD in a second band based on measurements in a first band.

[0040] Figure 2 shows exemplary components of BS110a and UE120a (for example, in the wireless communication network 100 in Figure 1) that may be used to implement aspects of the present disclosure.

[0041] In BS110a, the transmitting processor 220 may receive data from the data source 212 and control information from the controller / processor 240. Control information may be for the Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), Group Common PDCCH (GC PDCCH), etc. Data may be for the Physical Downlink Shared Channel (PDSCH), etc. A Media Access Control (MAC)-Control Element (MAC-CE) is a MAC layer communication structure that can be used to control command exchange between wireless nodes. MAC-CEs may be carried within a shared channel, such as the Physical Downlink Shared Channel (PDSCH), Physical Uplink Shared Channel (PUSCH), or Physical Sidelink Shared Channel (PSSCH).

[0042] Processor 220 may process data and control information (e.g., encoding and symbol mapping) to obtain data symbols and control symbols, respectively. Transmit processor 220 may also generate reference symbols, such as with respect to the primary synchronization signal (PSS), secondary synchronization signal (SSS), and channel status information reference signal (CSI-RS). Transmit (TX) multiple input multiple output (MIMO) processor 230 may, where applicable, perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols to provide output symbol streams to modulators (MODs) 232a-232t in the transceiver. Each modulator may process its respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process the output sample stream (e.g., analog conversion, amplification, filtering, and upconversion) to obtain a downlink signal. Downlink signals from modulators 232a to 232t within the transceiver can be transmitted via antennas 234a to 234t, respectively.

[0043] In UE120a, antennas 252a-252r may receive downlink signals from BS110a and provide the received signals to demodulators (DEMODs) 254a-254r within the transceiver, respectively. Each demodulator may adjust its respective received signal (e.g., filtering, amplification, downconversion, and digitization) to obtain an input sample. Each demodulator may further process the input sample (e.g., for OFDM) to obtain a received symbol. MIMO detector 256 can obtain received symbols from all demodulators 254a-254r within the transceiver and, where applicable, perform MIMO detection on the received symbols and provide the detected symbols. Receiving processor 258 can process the detected symbols (e.g., demodulate, deinterleave, and decode) and provide the decoded data for UE120a to data sink 260 and the decoded control information to controller / processor 280.

[0044] On the uplink, in UE120a, the transmit processor 264 can receive and process data from data source 262 (e.g., for a physical uplink shared channel (PUSCH)) and control information from controller / processor 280 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 264 can also generate reference symbols for reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 264 can be precoded by the TX MIMO processor 266, where applicable, further processed by modulators 254a-254r in the transceiver (e.g., for SC-FDM) and transmitted to BS110a. In BS110a, the uplink signal from UE120a is received by antenna 234, processed by demodulator 232 in the transceiver, detected by MIMO detector 236 where applicable, and further processed by receiving processor 238 to obtain decoded data and control information transmitted by UE120a. The receiving processor 238 may provide the decoded data to data sink 239 and the decoded control information to controller / processor 240.

[0045] Memories 242 and 282 can store data and program code related to BS110a and UE120a, respectively. Scheduler 244 can schedule the UE for data transmission on the downlink and / or uplink.

[0046] Antenna 252, processors 266, 258, 264, and / or controller / processor 280 of the UE120a, and / or antenna 234, processors 220, 230, 238, and / or controller / processor 240 of the BS110a may be used to perform various techniques and methods described herein. For example, as shown in Figure 2, the controller / processor 240 of the BS110a has a BFD manager 241, and the controller / processor 280 of the UE120a has a BFD manager 281. The BFD manager 241 and / or BFD manager 281 may be configured for BFD to a second band based on measurements in a first band, according to embodiments described herein. Other components of the UE120a and BS110a, as shown in the controller / processor, may be used to perform the operations described herein.

[0047] NR can utilize orthogonal frequency division multiplexing (OFDM) with cyclic prefixes (CP) on the uplink and downlink. NR can support half-duplex operation using time-division double (TDD). OFDM and single-carrier frequency division multiplexing (SC-FDM) divide the system bandwidth into multiple orthogonal subcarriers, commonly also called tones or bins. Each subcarrier can be modulated with data. The modulation symbol is transmitted in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers may depend on the system bandwidth. A minimum resource allocation, called a resource block (RB), may consist of 12 consecutive subcarriers. The system bandwidth may also be divided into subbands. For example, a subband may encompass multiple RBs. NR may support a base subcarrier spacing (SCS) of 15 kHz, and other SCSs (e.g., 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc.) may be defined relative to the base SCS.

[0048] Figure 3 shows an example of frame format 300 for NR. The transmission timelines for the downlink and uplink, respectively, may be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be divided into 10 subframes, each 1 ms long and having an index from 0 to 9. Each subframe may contain a variable number of slots depending on the SCS (e.g., 1, 2, 4, 8, 16, ... slots). Each slot may contain a variable number of symbol periods depending on the SCS (e.g., 7 or 14 symbols). The symbol periods within each slot may be assigned an index. The subslot structure refers to a transmission time interval with a shorter duration than a slot (e.g., 2, 3, or 4 symbols). Each symbol within a slot may indicate the link direction for data transmission (e.g., DL, UL, or flexible), and the link direction may be dynamically switched for each subframe. The link direction may be based on the slot format. Each slot may contain DL / UL data and DL / UL control information.

[0049] In some systems, the UE may be configured for beam fault detection (BFD). For example, the UE may detect a beam fault when channel estimation fails to meet the BFD threshold. The UE may be configured with beam fault recovery procedures using radio resource control (RRC) signaling. The beam fault recovery procedure may include sending beam recovery request messages to the serving BS (e.g., gNB). For example, when a beam fault is detected on a serving beam (e.g., serving SSB / CSI-RS), the UE may send a Random Access Channel (RACH) message to the serving BS indicating a new beam, such as by indicating a new synchronization signal block (SSB) or CSI-RS. The UE may detect a beam fault by counting beam fault instance indications from lower layers to the UE. If beam fault recovery is reconfigured by a higher layer during an ongoing random access procedure for beam fault recovery, the UE stops the ongoing random access procedure and starts a new random access procedure using the new configuration.

[0050] The RRC-configured beam fault detection and beam fault recovery parameters are: beamFailureInstanceMaxCount for beam fault detection; beamFailureDetectionTimer for beam fault detection; beamFailureRecoveryTimer for beam fault recovery procedure; rsrp-ThresholdSSB: RSRP threshold for beam fault recovery; powerRampingStep: powerRampingStep for beam fault recovery; powerRampingStepHighPriority: powerRampingStepHighPriority for beam fault recovery; preambleReceivedTargetPower: preambleReceivedTarget for beam fault recovery Power;preambleTransMax: preambleTransMax for beam fault recovery;scalingFactorBI: scalingFactorBI for beam fault recovery;ssb-perRACH-Occasion: ssb-perRACH-Occasion for beam fault recovery;ra-ResponseWindow: time window for monitoring the response to beam fault recovery using a race-free random access preamble;prach-ConfigurationIndex: prach-ConfigurationIndex for beam fault recovery;ra-ssb-OccasionMaskIndex: ra-ssb-OccasionMaskIndex for beam fault recovery;and / or ra-OccasionList: ra-OccasionList for beam fault recovery. The UE may also include the parameter BFI_CONTER: counter for beam fault instance indicators, which is initially set to 0.

[0051] In some examples, the UE and BS operate within the same environment, but the UE may operate at different frequencies with different channel identifications. Some cross-frequency correlation may exist between channel characteristics in different bands. Machine learning (ML) techniques may be used to predict channel characteristics in a second radio frequency band based on measurements in a first frequency band.

[0052] In some examples, ML techniques relate to training models, such as predictive models. This model may be used to predict (e.g., estimate) channel characteristics in a second band based on measurements in a first band. This model may be trained on training data (e.g., training information) that may include feedback, such as feedback associated with measurements in the first band compared to measurements in the second band. For example, as shown in Figure 4, measurements on the first band 403 in FR1 402 can be used to predict channel characteristics in the second band 405 in FR2 404. Alternatively, measurements in any of FR1 402, FR2 404, FR3 406, or FR4 408 (or another frequency range) can be used to predict channel characteristics in another frequency range of the frequency range.

[0053] Figure 5 shows an exemplary networked environment 500 in which a predictive model 524 is used for channel estimation, according to several aspects of the present disclosure. As shown in Figure 5, the networked environment 500 includes a node 520, a training system 530, and a training repository 515, all connected commutably via a network 505. The node 520 may be a UE (e.g., a UE 120a in a wireless communication network 100). The network 505 may be a wireless network, such as the wireless communication network 100, which may be a 5G NR network. Although the training system 530, node 520, and training repository 515 are shown as separate components in Figure 5, those skilled in the art should recognize that the training system 530, node 520, and training repository 515 may be implemented on any number of computing systems, either as one or more standalone systems or in a distributed environment.

[0054] The training system 530 generally includes a predictive model training manager 532 that uses training data to generate a predictive model 524 for channel estimation on a second band based on measurements within a first band. The predictive model 524 may be determined based on information in the training repository 515.

[0055] The training repository 515 may contain training data acquired before and / or after the deployment of node 520. Node 520 may be trained prior to its deployment in a simulated communication environment (e.g., in field tests, drive tests). For example, various channel estimations may be tested to obtain training information regarding measurements and / or estimations. This information may be stored in the training repository 515. After deployment, the training repository 515 may be updated to include feedback associated with the channel estimations performed by node 520. The training repository may also be updated with information from other BSs and / or UEs, based on their learning experience, which may be associated with procedures performed by other BSs and / or other UEs.

[0056] The predictive model training manager 532 may use the information in the training repository 515 to determine a predictive model 524 (e.g., an algorithm) to be used to estimate channel characteristics in a second band based on measurements in a first band. The predictive model training manager 532 may use various different types of machine learning algorithms to form the predictive model 524. The training system 530 may be located on node 520, on BS in network 505, or on a different entity that determines the predictive model 524. If located on a different entity, the predictive model 524 is provided to node 520. The training repository 515 may be a storage device, such as memory. The training repository 515 may be located on node 520, the training system 530, or another entity in network 505. The training repository 515 may be in cloud storage. The training repository 515 may receive training information from node 520, an entity in network 505 (e.g., BS or UE in network 505), the cloud, or other sources.

[0057] Machine learning can use any suitable machine learning algorithm. In some non-restrictive examples, machine learning algorithms include supervised learning algorithms, deep learning algorithms, artificial neural network algorithms, or other types of machine learning algorithms.

[0058] In some examples, machine learning (for example, used by training system 530) is performed using deep convolutional networks (DCNs). A DCN is a network of convolutional networks consisting of additional pooling and normalization layers. DCNs have achieved state-of-the-art performance for many tasks. DCNs can be trained using supervised learning, where both input and output targets are known for many samples and used to modify the network's weights by gradient descent. A DCN may be a feedforward network. In addition, as described above, connections from neurons in the first layer of a DCN to groups of neurons in the next higher layer are shared across neurons in the first layer. The feedforward and shared connections of a DCN can be leveraged for fast processing. The computational burden of a DCN can be even lower than, for example, the computational burden of a similarly sized neural network that includes recurrent or feedback connections.

[0059] In some examples, machine learning (for instance, as used by training system 530) is performed using neural networks. Neural networks can be designed with various connectivity patterns. In a feedforward network, information is passed from lower layers to higher layers, with each neuron in a given layer communicating with neurons in higher layers. Hierarchical representations can be constructed within the continuous layers of a feedforward network. Neural networks may have recurrent connectivity or feedback (also called top-down) connectivity. In recurrent connectivity, the output from a neuron in a given layer may communicate with another neuron in the same layer. Recurrent architectures can be useful when recognizing patterns that span one or more chunks of input data delivered sequentially to the neural network. Connectivity from a neuron in a given layer to a neuron in a lower layer is called feedback (or top-down) connectivity. Networks with many feedback connectivitys can be useful when the recognition of a higher-level concept helps discriminate certain lower-level features of the input.

[0060] An artificial neural network, which may consist of an interconnected group of artificial neurons (e.g., neuron models), represents a computing device or a method performed by a computing device. These neural networks can be used for a variety of applications and / or devices, such as Internet Protocol (IP) cameras, Internet of Things (IoT) devices, autonomous vehicles, and / or service robots. Individual nodes within an artificial neural network can emulate biological neurons by taking in input data and performing simple operations on the data. The results of the simple operations performed on the input data may be selectively passed to other neurons. Weight values ​​are associated with each vector and node in the network, and these values ​​constrain how input data relates to output data. For example, the input data of each node may be multiplied by the corresponding weight value, and the products may be summed. The sum of the products may be adjusted by a discretionary bias, and an activation function may be added to the result, resulting in the node's output signal or "output activation". Weight values ​​can initially be determined by the iterative flow of training data through the network (for example, weight values ​​are established during the training phase, when the network learns how to identify specific classes based on their typical input data characteristics).

[0061] Machine learning can be implemented using different types of artificial neural networks, such as recurrent neural networks (RNNs), multilayer perceptron (MLP) neural networks, and convolutional neural networks (CNNs) (as used by, for example, the training system 530). RNNs work by saving the output of a layer and feeding this output back into the input to help predict the results of that layer. In an MLP neural network, data can be fed into the input layer, and one or more hidden layers provide a level of abstraction to the data. Based on the abstraction data, predictions can then be made for the output layer. MLPs can be particularly well-suited to classification prediction problems when the input is assigned to a class or label. A convolutional neural network (CNN) is one type of feedforward artificial neural network. A convolutional neural network can contain a set of artificial neurons that tile the input space together, each having a receptive field (e.g., a spatially localized region of the input space). Convolutional neural networks have numerous applications. In particular, CNNs are widely used in the areas of pattern recognition and classification. In a layered neural network architecture, the output of the first layer of an artificial neuron becomes the input to the second layer of the artificial neuron, the output of the second layer of the artificial neuron becomes the output of the third layer of the artificial neuron, and so on. Convolutional neural networks can be trained to recognize a hierarchy of features. Computation in a convolutional neural network architecture can be distributed across a group of processing nodes, which may consist of one or more computational chains. These multilayer architectures can be trained one layer at a time and then fine-tuned using backpropagation.

[0062] In some examples, when using a machine learning algorithm, the training system 530 generates vectors from information in the training repository 515. In some examples, the training repository 515 stores the vectors. In some examples, the vectors map one or more features to labels. For example, the features may correspond to measurements on a first band. The labels may correspond to predicted channel characteristics of a second band (for example, according to some embodiments, the labels may be the estimated RSRP of a serving beam in the second band, as will be described in more detail below). The predictive model training manager 532 may use these vectors to train a predictive model 524 for node 520. As described above, the vectors may be associated with weights in a machine learning algorithm.

[0063] Using machine learning to estimate channel characteristics in a second band based on measurements in a first band can offer advantages. For example, measurements in the first band (e.g., the sub-6 GHz band, also known as FR1) may be simpler and more power-efficient than performing measurements in a different band (e.g., the mm-wave band, also known as FR2). This may be due to the hardware characteristics of the UE. Also, measurements in the second band can be reduced or eliminated by using measurements from the first band, thereby reducing the measurement overhead in the second band. Exemplary BFD in the second band based on measurements in the first band

[0064] In some embodiments, beam fault detection (BFD) in a second band may be based on measurements in a first band. For example, user equipment (UE) may estimate the channel characteristics of the second band based on measurements in the first band. For example, the UE may estimate the reference signal received power (RSRP) of the serving beam in the second band based on reference signal (RS) measurements in the first band. In some examples, the UE may use machine learning (ML) algorithms to estimate the channel characteristics of the second band based on measurements in the first band. In some examples, the UE may detect beam faults in the second band based on RS measurements in the first band.

[0065] In some cases, a UE may detect a beam fault in the second band without performing any RS measurements in the second band. For example, if the RSRP estimate for a serving beam in the second band, determined based on RS measurements in the first band, is at or above the BFD threshold for the second band, the UE may determine that there is no beam fault in the second band. However, if the channel estimate for the second band is below the BFD threshold for the second band (for example, when the RSRP estimate for the second band is below the BFD threshold for a number of measurement instances of the threshold for the second band), the UE may determine that there is a beam fault event in the second band.

[0066] In some cases, when the estimated RSRP for the second band is within the limits of the BFD threshold for the second band (e.g., close to the BFD threshold for the second band), the UE may detect beam faults in the second band by performing further RS ​​measurements in the second band. In this case, when the estimated RSRP for the second band exceeds the BFD threshold but is within the limits of the BFD threshold, the UE may request a BFD RS for the second band (e.g., "on-demand BFD RS") and then measure and determine a beam fault detection event in the second band. The UE may send a request for a BFD RS on PUCCH. If the measured RSRP on the second band exceeds the BFD threshold for the second band, the UE may determine that the serving beam in the second band is not in a beam fault condition. If the measured RSRP on the second band is less than the BFD threshold for the second band (for example, if the measured RSRP for the second band is less than the BFD threshold for a number of measured instances of the threshold for the second band), the UE may determine that a beam fault event has occurred for the second band.

[0067] In some embodiments, the UE may perform beam fault detection in a higher band (e.g., FR2) based on RS measurements in a lower band (e.g., FR1). The band may be any band and may be within any frequency range (e.g., FR1, FR2, FR4, etc.).

[0068] As shown in Figure 6, a node, such as node 520 in the environment 500 shown in Figure 5, may include a measurement manager 602. The measurement manager 602 may be configured to measure one or more RS on the first band in 604.

[0069] Measurements from the measurement manager 602 may be provided to the prediction model 524 in the channel estimation manager 522. The channel estimation manager 522 may input the measurements to a machine learning algorithm. The input may include any measurements within the first band. The input to the machine learning algorithm may include RS measurements within the first band. As shown in Figure 6, in some examples, the measurement manager 602 measures RS on the first band and provides measurement results 606 in 604 which may include reference signal received power (RSRP) measurements within the first band, UE positioning information (which may be used to learn beam direction, e.g.), raw channel measurements, channel impulse response (CIR) measurements, angle of emission (AoD) measurements (e.g., AoD of the strongest multipath component (MPC)), delay profile of the strongest MPC, and / or other measurements within the first band, as well as other inputs which may be used by the machine learning algorithm to estimate channel characteristics in the second band and / or predict RSRP for a beam in the second band (e.g., a serving beam).

[0070] In some examples, the output of a machine learning algorithm is a predicted RSRP value for a beam in a second band. As shown in Figure 6, the prediction model 524 may be configured to estimate the RSRP for the second band and provide those estimates to the BFD manager 610. In some examples, the prediction model may be located at the BS. For example, the UE may report measurements on the first band to the BS, which may use those measurements to estimate the channel characteristics of the second band. The BS may then provide the estimates to the UE and / or the BS may detect beam faults for the serving beam in the second band.

[0071] In some examples, the machine learning algorithm is trained on historical training data that includes measurements in a first band (including one or more previous measurements of the input as described above), previous measurements of channel characteristics in a second band, and / or previous measurements in a second band compared to measurements / estimates from the first band to train the machine learning algorithm. In some examples, the machine learning algorithm is further based on information about the environment. In some examples, the machine learning algorithm may be trained against a variety of different environments, and the predictive model used may be based on the current environment.

[0072] In some embodiments, the BFD manager 610 determines a beam in the second band that is faulty or near faulty, using channel characteristics for the second band (e.g., RSRP for a serving beam) estimated from RS measurements on the first band using a machine learning algorithm. For example, the BFD manager 610 may be configured in 612 to compare an RSRP estimate for the second band with a BFD threshold for the second band. The BFD manager 610 may also track the number of measurement instances where the RSRP estimate for the second band is less than the RSRP threshold for the second band. The BFD manager 610 may compare the number of measurement instances where the RSRP estimate for the second band is less than the RSRP threshold for the second band with a threshold number of measurement instances for the second band. The BFD manager 610 may determine a beam fault in the second band when the RSRP estimate for the second band is less than the RSRP threshold for the second band for measurement instances that are at or above the threshold number for the second band.

[0073] In some examples, if the BFD manager 610 determines that the beam is in a fault condition (when the estimated RSRP value for the second band is less than the BFD threshold for the second band for measurement instances that are at or exceed the threshold number), the BFD manager 610 may initiate a Beam Fault Recovery (BFR) at 616, for example, by sending a BFR message to BS. In this case, node 520 does not need to perform any BFD RS measurements on the second band. The BFR message may be a Random Access Channel (RACH) message indicating a new beam for the second band. In some examples, if the estimated RSRP exceeds the BFD threshold for the second band, the BFD manager 610 may determine that the beam is not in a fault condition.

[0074] In some cases, BFD Manager 610 may request the network (e.g., BS) to transmit RS on the second band based on measurements on the first band. This is sometimes called "on-demand" BFD RS. BFD Manager 610 may send the request on PUCCH. For example, when the estimated RSRP is close to or near the BFD threshold for the second band (e.g., above the BFD threshold but within the BFD threshold's limit range), BFD Manager 610 may send a request for BFD RS on the second band at 614. Node 520 then measures RS on the second band to determine the actual RSRP value for the second band and may determine, based on the actual RSRP measured on the RS on the second band, whether the beam for the second band is in a fault condition. When BFD Manager 610 determines that the beam is in a fault condition based on the actual RSRP, BFD Manager 610 may initiate BFR at 616. In some cases, if the actual RSRP is at or above the BFD threshold for the second band, the BFD manager 610 determines that the beam is not in a fault condition and does not initiate BFR. In some cases, if the estimated RSRP is not close to the BFD threshold for the second band (for example, exceeding the BFD threshold limit), the BFD manager 610 may determine that the beam is not close to a fault, does not need to request RS on the second band, and does not initiate BFR.

[0075] Therefore, node 520 can measure on the first band, which may be more power-efficient than measurements on the second band. Furthermore, the signaling overhead for the reference signal in the second band can be low by substituting the reference signal with the data, as node 520 can rely on measuring an "on-demand" reference signal on the second band, thereby having efficient signaling overhead and saving power.

[0076] Figure 7 is a flowchart illustrating exemplary operation 700 for wireless communication according to several embodiments of the present disclosure. Operation 700 may be performed, for example, by a UE (e.g., UE120a in the wireless communication network 100). Operation 700 may be implemented as a software component that runs and operates on one or more processors (e.g., controller / processor 280 in Figure 2). Furthermore, the transmission and reception of signals by the UE in operation 600 may be enabled, for example, by one or more antennas (e.g., antenna 252 in Figure 2). In some embodiments, the transmission and / or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller / processor 280) that acquires and / or outputs signals.

[0077] Operation 700 may be initiated in 705 by measuring one or more RSs on a first radio frequency band. In some examples, the first radio frequency band is in a lower frequency range than the second radio frequency band. In some examples, the first radio frequency band is in a sub-6 GHz frequency range, and the second radio frequency band is in a mmW frequency range. In some examples, the measurements on the first radio frequency band include one or more RSRP measurements, one or more positioning measurements, one or more raw channel measurements, one or more CIR measurements, one or more AoD measurements, one or more delay measurements, or a combination thereof.

[0078] In 710, the UE determines the BFD for the second radio frequency band based at least in part on one or more RS measurements on the first radio frequency band. In some examples, determining the BFD for the second radio frequency band involves estimating one or more channel parameters of the second radio frequency band using a machine learning (ML) algorithm that takes one or more RS measurements on the first radio frequency band as input. In some examples, the estimated one or more channel parameters include one or more estimated RSRP values.

[0079] In some examples, determining a BFD for a second radio frequency band includes reporting a BFD (e.g., initiating beam fault recovery) when the estimated RSRP for a serving beam in the second radio frequency band is less than the beam fault threshold for the second radio frequency band for measurement instances where it is or exceeds a threshold number for the second band. In some examples, determining a BFD for a second radio frequency band includes requesting one or more RSs on the second radio frequency band, measuring one or more RSs on the second radio frequency band, and reporting a BFD for the second radio frequency band (e.g., initiating and / or initiating a beam fault recovery procedure) when the estimated RSRP for a serving beam in the second radio frequency band is within the limits of the BFD threshold for the second radio frequency band.

[0080] Figure 8 is a flowchart illustrating exemplary operation 800 for wireless communication according to several embodiments of the present disclosure. Operation 800 may be performed, for example, by a UE (e.g., UE120a in the wireless communication network 100). Operation 800 may be implemented as a software component running and operated on one or more processors (e.g., controller / processor 280 in Figure 2). Furthermore, the transmission and reception of signals by the UE in operation 800 may be enabled, for example, by one or more antennas (e.g., antenna 252 in Figure 2). In some embodiments, the transmission and / or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller / processor 280) that acquires and / or outputs signals.

[0081] Operation 800 may be initiated in 805 by receiving one or more RSs on a first radio frequency band.

[0082] In 810, the UE may measure one or more RSs on the first radio frequency band. For example, the UE may perform RSRP measurements, positioning measurements, raw channel measurements, CIR measurements, AoD measurements, and / or delay measurements.

[0083] In 815, the UE may perform a BFD for a second radio frequency band based at least in part on one or more measurements of one or more RSs on a first radio frequency band. The first radio frequency band may be in a lower frequency range (e.g., a 6 GHz radio frequency range) than the second radio frequency band (e.g., a mmW radio frequency range). In 820, the UE may estimate one or more channel parameters (e.g., RSRP) of the second radio frequency band using an ML algorithm that takes one or more measurements of one or more RSs on the first radio frequency band as input. In 825, the UE compares the estimated one or more channel parameters of the second radio frequency band to a BFD threshold for the second radio frequency band. For example, the UE may compare the estimated one or more channel parameters of the second radio frequency band to a channel parameter threshold for the second radio frequency band. The UE may track the number of measurement instances in which the estimated one or more channel parameters of the second radio frequency band are less than the channel parameter threshold for the second radio frequency band. The UE may compare the number of measurement instances in which one or more estimated channel parameters for the second radio frequency band are less than the channel parameter threshold for the second radio frequency band to the threshold number of measurement instances for the second radio frequency band.

[0084] The UE may detect a beam obstruction to the second radio frequency band when one or more estimated channel parameters of the second radio frequency band are below a channel parameter threshold for the second radio frequency band for measurement instances where they are at or exceed a threshold for the second radio frequency band. In 830, the UE may request one or more RSs on the second radio frequency band when one or more estimated channel parameters of the second radio frequency band are within a predefined limit of the BFD threshold for the second radio frequency band. The UE may measure one or more RSs on the second radio frequency band (e.g., on-demand BFD RSs), compare one or more measurements of one or more RSs on the second radio frequency band to a channel parameter threshold for the second radio frequency band, and track the number of measurement instances where the measured values ​​of one or more RSs on the second radio frequency band are below the channel parameter threshold for the second radio frequency band.

[0085] In 835, the UE initiates a beam fault recovery procedure for the second radio frequency band, at least partially based on one or more RSs received on the first radio frequency band.

[0086] Figure 9 is a flowchart illustrating exemplary operation 900 for wireless communication according to several embodiments of the present disclosure. Operation 900 may be performed, for example, by a BS (e.g., BS110a in the wireless communication network 100). Operation 900 may be a complementary operation by the BS to operation 900 performed by the UE. Operation 900 may be implemented as a software component that runs and operates on one or more processors (e.g., the controller / processor 240 in Figure 2). Furthermore, the transmission and reception of signals by the BS in operation 900 may be enabled, for example, by one or more antennas (e.g., the antenna 234 in Figure 2). In some embodiments, the transmission and / or reception of signals by the BS may be implemented via a bus interface of one or more processors (e.g., the controller / processor 240) that acquire and / or output signals.

[0087] Operation 900 may be initiated in 905 by transmitting one or more first RSs to the UE on a first radio frequency band.

[0088] In 910, the BS receives a request from the UE to transmit a second or more RS on a second radio frequency band in response to a first or more RS on a first radio frequency band.

[0089] In 915, BS transmits one or more second RSs to UE on the second radio frequency band.

[0090] In some examples, in 920, the BS receives a beam fault recovery request message from the UE for a second radio frequency band. For example, the beam fault recovery request message may be at least partially based on one or more second RSs transmitted on the second radio frequency band.

[0091] In some examples, the first radio frequency band is in the sub-6GHz frequency range, and the second radio frequency band is in the mm wave frequency range.

[0092] Figure 10A is a decision tree diagram showing an exemplary operation 1000a for wireless communication by a UE according to some aspects of the present disclosure. As shown in Figure 10A, the UE measures one or more RSs on a first band in 1002. In 1004, the UE estimates the RSRP of the serving node on a second band based on the measurements in the first band (e.g., measurements performed in 1002). In 1006, the UE compares the estimated RSRP for the second band to a BFD threshold for the second band. If the estimated RSRP for the second band is at or above the BFD threshold for the second band, in 1022, the UE may determine that there is no beam obstruction (and may return to block 1002 and measure the RS on the first band). If the estimated RSRP for the second band is below the BFD threshold for the second band, the UE may initiate a BFR for the second band in 1012. For example, the UE may count measurement instances where the estimated RSRP for the second band is less than the BFD threshold for the second band. If the number of measurement instances where the estimated RSRP for the second band is less than the BFD threshold for the second band is less than the threshold number of measurement instances, the UE may return to block 1002 and measure the RS on the first band. If the number of measurement instances where the estimated RSRP for the second band is at or above the BFD threshold for the second band is at or above the threshold number of measurement instances, the UE may initiate BFR in block 1012.

[0093] Figure 10B shows another decision tree diagram illustrating exemplary operation 1000b for wireless communication by a UE according to some aspects of the present disclosure. As shown in Figure 10B, the UE may further verify in 1006b whether the estimated RSRP is within the limits of the BFD threshold for the second band. If the UE determines in 1006b that the estimated RSRP for the second band exceeds the limits of the BFD threshold for the second band, the UE may determine in 1024b that there is no beam obstruction (and may return to block 1002 and measure the RS on the first band). On the other hand, if the UE determines in 1006b that the estimated RSRP exceeds the BFD threshold and is within the limits of the BFD threshold for the second band, the UE may request one or more BFD RSs for the second band (e.g., on-demand BFD RSs) in 1014. In 1016, the UE measures one or more BFD RSs on the second band. The UE may determine the actual RSRP for the second band based on the measured BFD RS for the second band. In 1018, the UE determines whether the actual measured RSRP for the second band is less than the BFD threshold for the second band. If the RSRP is not less than the BFD threshold, the UE determines in 1022 that there is no beam fault for the second band (for example, for a serving cell for the second band). If the RSRP is less than the BFD threshold, the UE may initiate beam fault recovery for the second band in 1020. For example, the UE may count the measurement instances in which the actual measured RSRP for the second band is less than the BFD threshold for the second band. If the number of measurement instances in which the actual measured RSRP for the second band is less than the BFD threshold for the second band is less than the threshold number of measurement instances, the UE may return to block 1016 and measure the RS on the second band. When the number of measurement instances in which the actual measured RSRP for the second band is or exceeds the BFD threshold for the second band is or exceeds the threshold number of measurement instances, the UE initiates BFD at 1020.

[0094] Figure 11A is a call flow illustrating exemplary signaling 1100a according to several aspects of the present disclosure. In 1102, the BS transmits one or more RSs to the UE on the first band. In 1104, the UE measures one or more RSs on the first band. In some examples, no beam fault event occurs. In this case, in 1106a, the UE estimates one or more channel characteristics on the second band, and the estimated channel characteristics are at or above the BFD threshold, and in 1108a, the UE may determine that there are no beam faults on the second band. In some examples, a beam fault event occurs. In this case, in 1106b, the UE estimates one or more channel characteristics on the second band, and the estimated channel characteristics are below the BFD threshold, and in 1108b, the UE may initiate beam fault recovery on the second band when the number of measurement instances in which the estimated channel characteristics are below the BFD threshold is at or above the threshold number of measurement instances.

[0095] Figure 11B is a call flow illustrating exemplary signaling 1100b according to several aspects of the present disclosure. In 1102, the BS transmits one or more RSs on the first band to the UE. In 1104, the UE measures one or more RSs on the first band. In some examples, the beam may be close to a fault. In 1106c, the UE estimates one or more channel characteristics on the second band, and the estimated channel characteristics are within the BFD threshold. In 1108c, the UE requests one or more RSs on the second band. In 1110, the BS transmits the requested one or more RSs on the second band to the UE. In 1112, the UE measures one or more RSs on the second band. In some examples, no beam fault event has occurred. In 1114a, the measured channel characteristics are at or above the BFD threshold, and in 1116a, the UE may determine that there is no beam fault on the second band. In some examples, a beam fault event has occurred. In 1114b, if the measured channel characteristics are below the BFD threshold, and in 1116b, if the number of measurement instances in which the estimated channel characteristics are below the BFD threshold is equal to or exceeds the threshold number of measurement instances, the UE may initiate beam fault recovery on the second band.

[0096] Figure 12 shows a communication device 1200 which may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for techniques disclosed herein, such as the operations shown in Figure 7 and / or Figure 8. 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 various signals as 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 that are received and / or will be transmitted by the communication device 1200.

[0097] The processing system 1202 includes a processor 1204 coupled to a computer-readable medium / memory 1212 via a bus 1206. In some embodiments, the computer-readable medium / memory 1212 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1204, cause the processor 1204 to perform the operations shown in Figures 7 and / or 8, or other operations to perform various techniques described herein with respect to a BFD on a second band based on measurements on a first band. In some embodiments, the computer-readable medium / memory 1212 stores a code 1214 for receiving, a code 1216 for measuring, a code 1218 for executing, a code 1220 for estimating, a code 1222 for comparing, a code 1224 for requesting, and / or a code 1226 for initiating, according to embodiments of this disclosure. In some embodiments, the processor 1204 has circuitry configured to implement the code stored in the computer-readable medium / memory 1212. The processor 1204 includes, as described in the embodiments of the present disclosure, a circuit 1228 for receiving, a circuit 1230 for measuring, a circuit 1232 for executing, a circuit 1234 for estimating, a circuit 1236 for comparing, a circuit 1238 for requesting, and / or a circuit 1240 for initiating.

[0098] Figure 13 shows a communication device 1300 which may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operation shown in Figure 9. The communication device 1300 includes a processing system 1302 coupled to a transceiver 1308 (e.g., a transmitter and / or receiver). The transceiver 1308 is configured to transmit and receive signals for the communication device 1300, such as various signals as described herein, via an antenna 1310. The processing system 1302 may be configured to perform processing functions for the communication device 1300, including processing signals that are received and / or will be transmitted by the communication device 1300.

[0099] The processing system 1302 includes a processor 1304 coupled to a computer-readable medium / memory 1312 via a bus 1306. In some embodiments, the computer-readable medium / memory 1312 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1304, cause the processor 1304 to perform the operations shown in Figure 9, or other operations to perform various techniques described herein with respect to BFD on a second bandwidth based on measurements on a first bandwidth. In some embodiments, the computer-readable medium / memory 1312 stores a code 1314 for transmitting one or more first RSs on a first radio frequency band to the UE, a code 1316 for receiving a request from the UE for one or more second RSs on a second radio frequency band in response to the one or more first RSs on the first radio frequency band, a code 1318 for transmitting one or more second RSs on a second radio frequency band to the UE, and / or a code 1320 for receiving a beam fault recovery request message from the UE for a second radio frequency band. In some embodiments, the processor 1304 has circuitry configured to implement the codes stored in the computer-readable medium / memory 1312. The processor 1304 includes a circuit 1322 for transmitting one or more first RSs on a first radio frequency band to the UE, a circuit 1324 for receiving a request from the UE to transmit one or more second RSs on a second radio frequency band in response to the one or more first RSs on the first radio frequency band, a circuit 1326 for transmitting one or more second RSs on a second radio frequency band to the UE, and / or a circuit 1328 for receiving a beam fault recovery request message from the UE for the second radio frequency band. Exemplary aspects

[0100] Implementation examples are described in the following numbered clauses.

[0101] Embodiment 1. A method for wireless communication by user equipment (UE), comprising the steps of receiving one or more reference signals (RS) on a first radio frequency band, and initiating a beam obstruction recovery procedure for a second radio frequency band, at least in part, based on one or more RS received on the first radio frequency band.

[0102] Embodiment 2. The method of Embodiment 1, further comprising the steps of measuring one or more RSs on a first radio frequency band and performing beam fault detection (BFD) on a second radio frequency band based at least in part on one or more measurements of the one or more RSs on the first radio frequency band.

[0103] Embodiment 3. The method of Embodiment 2, wherein the step of performing BFD for a second radio frequency band includes the steps of: estimating one or more channel parameters of the second radio frequency band using a machine learning (ML) algorithm that takes one or more measurements of one or more RS on a first radio frequency band as input; and comparing the estimated one or more channel parameters of the second radio frequency band with a BFD threshold for the second radio frequency band.

[0104] Embodiment 4. The method of Embodiment 3, wherein the step of performing BFD on a second radio frequency band includes the step of detecting a beam obstruction on a second radio frequency band when the estimated one or more channel parameters of the second radio frequency band are less than a BFD threshold for the second radio frequency band for measurement instances in which the number of channel parameters of the second radio frequency band is or exceeds a threshold number.

[0105] Embodiment 5. Any one of Embodiments 3 to 4, wherein the step of performing BFD for a second radio frequency band includes the steps of: requesting one or more RSs on the second radio frequency band when one or more estimated channel parameters of the second radio frequency band are within a predefined limit of a BFD threshold for the second radio frequency band; measuring one or more RSs on the second radio frequency band; and comparing one or more measurements of one or more RSs on the second radio frequency band with a BFD threshold for the second radio frequency band.

[0106] Embodiment 6. The method of Embodiment 5, wherein the step of requesting one or more RSs on a second radio frequency band includes the step of requesting a base station (BS) to transmit one or more on-demand beam fault detection (BFD) RSs on the second radio frequency band.

[0107] Embodiment 7. Any one of Embodiments 2 to 6, wherein one or more measurements on a first radio frequency band include one or more reference signal received power (RSRP) measurements, one or more positioning measurements, one or more raw channel measurements, one or more channel impulse response (CIR) measurements, one or more angle of discharge (AoD) measurements, one or more delay measurements, or a combination thereof.

[0108] Embodiment 8. Any one of Embodiments 2 to 7, wherein one or more estimated channel parameters include one or more estimated reference signal received power (RSRP) values.

[0109] Embodiment 9. Any one of Embodiments 1 to 8, wherein the first radio frequency band is in the sub-6 GHz radio frequency range and the second radio frequency band is in the millimeter wave (mmW) radio frequency range.

[0110] Embodiment 10. A method for wireless communication by a base station (BS), comprising the steps of: transmitting one or more first reference signals (RS) on a first radio frequency band to a user device (UE); receiving a request from the UE to transmit one or more second RSs on a second radio frequency band in response to one or more first RSs on the first radio frequency band; and transmitting one or more second RSs on the second radio frequency band to the UE.

[0111] Embodiment 11. The method of Embodiment 10, further comprising the step of receiving a beam obstruction recovery request message for a second radio frequency band from the UE.

[0112] Embodiment 12. The method of Embodiment 10 or Embodiment 11, wherein the first radio frequency band is in the sub-6 GHz radio frequency range and the second radio frequency band is in the millimeter wave (mmW) radio frequency range.

[0113] Embodiment 13. Any one of embodiments 10 to 12, wherein the step of receiving a request from a UE to transmit one or more second RSs on a second radio frequency band includes the step of receiving the request on a physical uplink control channel (PUCCH).

[0114] Embodiment 14. Any one of embodiments 10 to 13, wherein the step of receiving a request from a UE to transmit one or more second RSs on a second radio frequency band includes the step of receiving a request from a UE to transmit one or more on-demand beam fault detection (BFD) RSs on a second radio frequency band.

[0115] Embodiment 15. An apparatus comprising means for carrying out any one of Embodiments 1 to 14.

[0116] Embodiment 16. An apparatus comprising at least one processor and memory coupled to at least one processor, wherein the memory comprises code executable by at least one processor for causing the apparatus to perform any one of Embodiments 1 to 14.

[0117] Embodiment 17. A computer-readable medium storing computer-executable code for wireless communication, which, when executed by at least one processor, causes a device to perform any one of the methods of Embodiments 1 to 14. Further consideration

[0118] The techniques described herein can be used for a variety of wireless communication technologies, including NR (e.g., 5G NR), 3GPP Long-Term Evolution (LTE), LTE-Advanced (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. CDMA networks may implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Broadband CDMA (WCDMA®) and other variations of CDMA. cdma2000 covers the IS-2000, IS-95, and IS-856 standards. TDMA networks may implement radio technologies such as the Global System for Mobile Communications (GSM). OFDMA networks can implement wireless technologies such as NR (e.g., 5G RA), Advanced UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDMA. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are documented in documents from an organization called the "Third Generation Partnership Project" (3GPP). cdma2000 and UMB are documented in documents from an organization called the "Third Generation Partnership Project II" (3GPP2). NR is a new wireless communication technology under development.

[0119] 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 term “cell” can be used interchangeably with BS, Next Generation Node B (gNB or gNode B), Access Point (AP), Distributed Unit (DU), Carrier, or Transmit / Receive Point (TRP). A BS can provide communication coverage to macrocells, picocells, femtocells, and / or other types of cells. A macrocell can cover a relatively large geographical area (e.g., a radius of several kilometers) and can enable unrestricted access by UEs subscribing to the service. A picocell can cover a relatively small geographical area and can enable unrestricted access by UEs subscribing to the service. A femtocell can cover a relatively small geographical area (e.g., a home) and can enable limited access by UEs associated with a femtocell (e.g., UEs in a Limited Subscriber Group (CSG), UEs for users in a home, etc.). BS for macrocells is sometimes called macroBS. BS for picocells is sometimes called picoBS. BS for femtocells is sometimes called femtoBS or homeBS.

[0120] UEs may also be called mobile stations, terminals, access terminals, subscriber units, stations, Customer Premises Equipment (CPE), cellular phones, smartphones, personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, laptop computers, cordless phones, wireless local loop (WLL) stations, tablet computers, cameras, gaming devices, netbooks, smartbooks, ultrabooks, appliances, medical devices or equipment, biosensors / biometric devices, smartwatches, smart clothing, smart glasses, smart wristbands, smart jewelry (e.g., smart rings, smart bracelets, etc.), wearable devices, entertainment devices (e.g., music devices, video devices, satellite radios, etc.), vehicle components or vehicle sensors, smart meters / smart sensors, industrial manufacturing equipment, global positioning system devices, or any other suitable device configured to communicate via wireless or wired media. Some UEs may be considered machine-type communications (MTC) devices or advanced MTC (eMTC) devices. MTC UEs and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that can communicate with BS, another device (e.g., a remote device), or any other entity. Wireless nodes may provide connectivity or network access for a network (e.g., the Internet or a wide area network such as a cellular network) via, for example, a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, and IoT devices may be narrowband IoT (NB-IoT) devices.

[0121] In some examples, access to an 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. A scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more dependent entities. That is, for scheduled communication, dependent entities use the resources allocated by the scheduling entity. A base station is not the only entity that can function as a scheduling entity. In some examples, a UE may function as a scheduling entity, scheduling resources for one or more dependent entities (e.g., one or more other UEs), and the other UEs may utilize the resources scheduled by that UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network and / or a mesh network. In one example of a mesh network, UEs may communicate directly with each other in addition to communicating with scheduling entities.

[0122] The methods disclosed herein include one or more steps or actions for achieving the method. The steps and / or actions of the method may be interchanged 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 any particular steps and / or actions may be modified without departing from the scope of the claims.

[0123] As used herein, the phrase “at least one of” the list of items refers to any combination of those items that includes a single member. For example, “at least one of a, b, or c” is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiple identical elements (for example, aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c).

[0124] As used herein, the term “decision-making” encompasses a wide variety of actions. For example, “decision-making” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, database, or other data structure), and confirming. It may also include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and resolving, selecting, choosing, and establishing.

[0125] The above description is provided to enable any person skilled in the art to practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to a person skilled in the art, and the general principles defined herein may apply to other embodiments. Accordingly, the claims should not be limited to the embodiments shown herein, but should be given the entire scope consistent with the language of the claims, and references to singular elements should mean "one or more" rather than "one unique" unless otherwise explicitly stated. Unless otherwise explicitly stated, the term "several" refers to one or more. All structural and functional equivalents of elements of the various embodiments described throughout this disclosure, whether known to a person skilled in the art or to be known later, are expressly incorporated herein by reference and are encompassed by the claims. Furthermore, nothing disclosed herein is intended to be made public, whether such disclosure is expressly enumerated in the claims or not. No element of a claim should be construed under Section 112(f) of the United States Patent Act unless it is explicitly enumerated using the phrase “means for” or, in the case of a method claim, unless it is enumerated using the phrase “steps for”

[0126] The various operations of the methods described above can be performed by any suitable means capable of performing the corresponding functions. These means may include, but are not limited to, various hardware and / or software components and / or modules, including circuits, application-specific integrated circuits (ASICs), or processors. Generally, where operations are shown in the figures, those operations may have corresponding relative means-plus-function components with similar numbering.

[0127] The various exemplary logic blocks, modules, and circuits described in connection with this disclosure may be implemented or run using general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices (PLDs), 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 alternatively, the processor may be any commercially available processor, controller, microcontroller or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors working with a DSP core, or any other such configuration.

[0128] When implemented in hardware, an exemplary hardware configuration may include a processing system within a wireless node. The processing system may be implemented using a bus architecture. The bus may include any number of interconnecting buses and bridges, depending on the specific application of the processing system and the overall design constraints. The bus can link various circuits to each other, including processors, machine-readable media, and bus interfaces. Bus interfaces may be used, among other things, to connect network adapters to the processing system via the bus. Network adapters may be used to implement the signal processing functions of the PHY layer. In the case of a user terminal (see Figure 1), a user interface (e.g., 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, and power management circuits, but these circuits are well known in the art and therefore will not be described further. The processor may be implemented using one or more general-purpose processors and / or dedicated processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits capable of running software. Those skilled in the art will recognize the best way to implement the functions described for the processing system, depending on the specific application and the overall design constraints imposed on the entire system.

[0129] When implemented in software, functions may be stored on or transmitted via computer-readable media as one or more instructions or code. Software is 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 include both computer storage media and communication media, including any medium that facilitates the transfer of computer programs from one location to another. A processor may be responsible for general operations, including managing buses and executing software modules stored on machine-readable storage media. Computer-readable storage media may be coupled to the processor so that the processor can read information from and write information to the storage media. Alternatively, the storage media may be integrated with the processor. For example, machine-readable media may include computer-readable storage media having instructions stored thereon, separate from transmission lines, data-modulated carriers, and / or wireless nodes, all of which may be accessed by the processor via a bus interface. As an alternative or addition, machine-readable media or any part thereof may be integrated into the processor, such as caches and / or general-purpose register files. Examples of machine-readable storage media may include, for example, random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be embodied in computer program products.

[0130] A software module may consist of 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 contain several software modules. When executed by a device such as a processor, a software module contains instructions that cause the processing system to perform various functions. A software module may include a send module and a receive module. Each software module may reside in a single storage device or be distributed across multiple storage devices. For example, when a trigger event occurs, a software module may be loaded from a hard drive into RAM. While a software module is executing, the processor may load some of the instructions into a cache to increase access speed. One or more cache lines may then be loaded into a general-purpose register file to be executed by the processor. When the functionality of a software module is referred to below, it will be understood that such functionality is implemented by the processor when instructions from that software module are being executed.

[0131] Furthermore, any connection is appropriately referred to as a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. As used herein, disk and disc include compact disc (CD), laserdisc (disc), optical disc (disc), digital versatile disc (disc) (DVD), floppy disk (disk), and Blu-ray (disc), where disk typically reproduces data magnetically, and disc (disc) reproduces data optically using a laser. Thus, in some embodiments, a computer-readable medium may include non-temporary computer-readable medium (e.g., tangible medium). In addition, in other embodiments, the computer-readable medium may include a temporary computer-readable medium (e.g., a signal). The above combinations should also be included within the scope of the computer-readable medium.

[0132] Accordingly, some embodiments may include computer program products for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having stored (and / or encoded) instructions, the instructions being executable by one or more processors to perform the operations described herein, such as the instructions for performing the operations described herein and shown in Figures 4 to 13.

[0133] Furthermore, it should be understood that modules and / or other suitable means for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by user terminals and / or base stations, where applicable. For example, such devices may be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, the various methods described herein may be provided via storage means (e.g., physical storage media such as RAM, ROM, compact disks (CDs), or floppy disks) so that user terminals and / or base stations can obtain the various methods once they couple or provide the storage means to a device. Moreover, any other suitable techniques for providing the methods and techniques described herein to a device may be utilized.

[0134] It should be understood that the claims are not limited to the exact configurations and components exemplified above. Various modifications, changes, and variations may be made to the configuration, operation, and details of the methods and apparatus described above without departing from the claims. [Explanation of Symbols]

[0135] 100 Wireless Communication Networks 101 Serving Beam 102a Macrocell 102b Macrocell 102c Macrocell 102x picocell 102y Femtocell 102z femtocell 110 BS 110a~z Base station (BS) 110r relay station 112 BFD Manager 120 UE 120a~y User Equipment (UE) 122 BFD Manager 130 Network Controllers 132 Core Network 134 core network nodes 212 data sources 220 Transmitting Processors, Processors 230 Transmit (TX) Multiple Input Multiple Output (MIMO) Processor, Processor 232 Demodulator 232a~232t Modulator (MOD) 234 Antenna 234a~234t Antenna 236 MIMO detector 238 receiving processor, processor 239 Data Sync 240 Controllers / Processors, Processors 241 BFD Manager 242 memory 244 Scheduler 252 Antenna 252a~252r Antenna 254a~254r Demodulator 256 MIMO detector 258 receiving processors, processor 260 Data Sync 262 data sources 264 Transmitting Processor, Processor 266 processors 280 Controllers / Processors 281 BFD Manager 282 memory 300 frame format 402 FR1 403 First Bandwidth 404 FR2 405 Second Band 406 FR3 408 FR4 500 Network connection environment, environment 505 Network 515 Training Repository 520 nodes 522 Channel Estimation Manager 524 Predictive Models 530 Training System 532 Predictive Model Training Manager 602 Measurement Manager 610 BFD Manager 620 nodes 700 operations 800 operations 900 operations 1000a operation 1000b operation 1100a signaling 1100b Signaling 1200 communication devices 1202 Processing System 1204 Processor 1206 Bus 1208 Transceiver 1210 Antenna 1212 Computer-readable media / memory 1214 Code to receive 1216 Code for measurement 1218 Code to execute 1220 Code for estimation 1222 Code for comparison 1224 Code to request 1226 Code to start 1228 Circuit for receiving 1230 Circuit for measurement 1232 Circuit for execution 1234 Circuit for estimation 1236 Circuit for comparison 1238 Circuit for requesting 1240 Circuit for starting 1300 communication devices 1302 Processing System 1304 Processor 1306 Bus 1308 Transceiver 1310 Antenna 1312 Computer-readable media / memory 1314 Code for transmitting one or more first RSs to the UE on a first radio frequency band 1316 Code for receiving a request from a UE to transmit a second one or more RS on a second radio frequency band in response to a first one or more RS on a first radio frequency band. 1318 Code for transmitting one or more second RSs to the UE on a second radio frequency band 1320 Code for receiving beam obstruction recovery request messages from the UE for the second radio frequency band 1322 Circuit for transmitting one or more first RSs to a UE on a first radio frequency band 1324 Circuit for receiving a request from a UE to transmit a second one or more RS on a second radio frequency band in response to a first one or more RS on a first radio frequency band. 1326 Circuit for transmitting one or more second RSs to a UE on a second radio frequency band. 1328 Circuit for receiving beam fault recovery request messages from the UE for the second radio frequency band.

Claims

1. A method for wireless communication by a user equipment (UE), comprising: receiving, on a first radio frequency band, one or more reference signals (RS); measuring the one or more RS on the first radio frequency band; estimating one or more channel parameters of a second radio frequency band based on one or more measurement values of the one or more RS on the first radio frequency band; performing beam failure detection (BFD) for the second radio frequency band by comparing the estimated one or more channel parameters of the second radio frequency band with a BFD threshold for the second radio frequency band; determining that there is no beam failure in the second radio frequency band in response to the estimated one or more channel parameters exceeding the BFD threshold; initiating a beam failure recovery procedure for the second radio frequency band in response to the estimated one or more channel parameters being less than the BFD threshold. A method as described above.

2. The step of performing the BFD for the second radio frequency band comprises estimating one or more channel parameters of the second radio frequency band using a machine learning (ML) algorithm that uses the one or more measurement values of the one or more RS on the first radio frequency band as an input. The method according to claim 1.

3. The step of performing the BFD for the second radio frequency band comprises detecting a beam failure for the second radio frequency band when the estimated one or more channel parameters of the second radio frequency band are less than the BFD threshold for measurement instances that are at or above a threshold number. The method according to claim 1.

4. The step of performing the BFD for the second radio frequency band When the estimated one or more channel parameters of the second radio frequency band are within a predefined margin of the BFD threshold for the second radio frequency band, requesting one or more reference signals (RSs) on the second radio frequency band; measuring the one or more second RSs on the second radio frequency band; comparing one or more measured values of the one or more second RSs on the second radio frequency band with the BFD threshold for the second radio frequency band; The method according to claim 1, comprising:

5. The step of requesting the one or more second RSs on the second radio frequency band includes requesting a base station (BS) to transmit one or more on-demand beam failure detection (BFD) RSs on the second radio frequency band. The method according to claim 4.

6. The one or more measured values on the first radio frequency band include one or more reference signal received power (RSRP) measured values, one or more positioning measured values, one or more raw channel measured values, one or more channel impulse response (CIR) measured values, one or more angle of departure (AoD) measured values, one or more delay measured values, or a combination thereof. The method according to claim 1.

7. The estimated one or more channel parameters include estimated one or more reference signal received power (RSRP) values. The method according to claim 1.

8. The first radio frequency band is within the sub-6 GHz radio frequency range, and the second radio frequency band is within the millimeter wave (mmW) radio frequency range. The method according to claim 1.

9. An apparatus for wireless communication, comprising: means for receiving one or more first reference signals (RSs) on a first radio frequency band; measuring the one or more first RSs on the first radio frequency band; estimating one or more channel parameters of a second radio frequency band based on one or more measured values of the one or more first RSs on the first radio frequency band; Performing beam failure detection (BFD) for the second radio frequency band by comparing the estimated one or more channel parameters of the second radio frequency band with a BFD threshold for the second radio frequency band; Determining that there is no beam failure in the second radio frequency band in response to the estimated one or more channel parameters exceeding the BFD threshold; Means for initiating a beam failure recovery procedure for the second radio frequency band in response to the estimated one or more channel parameters being less than the BFD threshold. An apparatus. **Claim 10** Further comprising means for estimating one or more channel parameters of the second radio frequency band using a machine learning (ML) algorithm that uses the one or more measurements of the first one or more RSs on the first radio frequency band as an input. The apparatus according to claim 9. **Claim 11** Further comprising means for detecting a beam failure for the second radio frequency band when the estimated one or more channel parameters of the second radio frequency band are less than the BFD threshold for measurement instances that are at or above a threshold number. The apparatus according to claim 9. **Claim 12** Means for requesting a second one or more RSs on the second radio frequency band when the estimated one or more channel parameters of the second radio frequency band are within a predefined margin of the BFD threshold for the second radio frequency band; Means for measuring the second one or more RSs on the second radio frequency band; Further comprising means for comparing one or more measurements of the second one or more RSs on the second radio frequency band with the BFD threshold for the second radio frequency band. The apparatus according to claim 9. **Claim 13** Further comprising means for requesting a base station (BS) to transmit one or more on-demand beam failure detection (BFD) RSs on the second radio frequency band. The apparatus according to claim 12.

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