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 of and priority to U.S. Provisional Patent Application No. 62 / 968,668, filed January 31, 2020, which claims priority to U.S. Provisional Patent Application No. 17 / 158,656, filed January 26, 2021, both of which are incorporated herein by reference in their entireties.

[0003] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for beam obstruction detection. [Background technology]

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include Third Generation Partnership Project (3GPP®) Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems, to name a few.

[0005] These multiple access technologies are being adopted in various telecommunications standards to provide common protocols that allow different wireless devices to communicate on a city, national, regional, or even global scale. New Radio (e.g., 5G NR) is an example of an emerging telecommunications standard. NR is a set of enhancements to the LTE mobile standard promulgated 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 (CPs) on the downlink (DL) and uplink (UL). To these ends, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0006] However, as demand for mobile broadband access continues to grow, 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 these technologies. Summary of the Invention [Means for solving the problem]

[0007] The systems, methods, and devices of the present disclosure each have several aspects, no single aspect of which is solely responsible for its desirable attributes. Without limiting the scope of the present disclosure as expressed by the following claims, some features will now be briefly described. After considering this description, and particularly after reading the section entitled "Detailed Description of the Invention," one will understand how the features of the present disclosure provide advantages, including improved beam fault detection (BFD).

[0008] Certain aspects of the subject matter described in this disclosure may be implemented in a method for wireless communication by a user equipment (UE), generally including receiving one or more reference signals (RS) on a first radio frequency band and initiating a beam failure recovery procedure on a second radio frequency band based at least in part on the one or more RSs received on the first radio frequency band.

[0009] Certain aspects of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication by a UE, generally including: means for receiving one or more RSs on a first radio frequency band; and means for initiating a beam failure recovery procedure on a second radio frequency band based at least in part on the one or more RSs received on the first radio frequency band.

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

[0011] Certain aspects of the subject matter described in this disclosure may be implemented in a computer-readable medium having computer-executable code recorded thereon for wireless communications. The computer-readable medium generally includes code for receiving one or more RSs on a first radio frequency band and code for initiating a beam failure recovery procedure on a second radio frequency band based at least in part on the one or more RSs received on the first radio frequency band.

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

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

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

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

[0016] Certain aspects of the subject matter described in this disclosure may be implemented in an apparatus for wireless communications. The apparatus 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 the one or more RSs on the first radio frequency band.

[0017] Certain aspects of the subject matter described in this disclosure may be implemented in an apparatus for wireless communications. The apparatus generally includes: means for transmitting first one or more RSs to a UE on a first radio frequency band; means for receiving a request from the UE to transmit second one or more RSs on a second radio frequency band in response to the first one or more RSs on the first radio frequency band; and means for transmitting the second one or more RSs to the UE on the second radio frequency band.

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

[0019] Certain aspects of the subject matter described in this disclosure may be implemented in a computer-readable medium having computer-executable code recorded thereon for wireless communications. The apparatus generally includes code for transmitting a first one or more RSs to a UE over a first radio frequency band, code for receiving a request from the UE to transmit a second one or more RSs over a second radio frequency band in response to the first one or more RSs on the first radio frequency band, and code for transmitting the second one or more RSs to the UE over the second radio frequency band.

[0020] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of the various aspects may be employed.

[0021] So that the above-mentioned features of the present disclosure may be understood in detail, a more particular description may be had by reference to embodiments, some of which are illustrated in the drawings. However, since the present description may lead to other equally effective embodiments, it should be noted that the accompanying drawings illustrate only some typical embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a block diagram conceptually illustrating an example telecommunications system in accordance with certain aspects of the present disclosure. [Figure 2] FIG. 1 is a block diagram conceptually illustrating an example base station (BS) and user equipment (UE) design in accordance with certain aspects of the present disclosure. [Figure 3] FIG. 1 illustrates an example frame format for New Radio (NR) in accordance with certain aspects of the present disclosure. [Figure 4]FIG. 1 illustrates exemplary frequency ranges in accordance with some aspects of the present disclosure. [Figure 5] FIG. 1 illustrates an example networked environment in which a predictive model is used for channel estimation, in accordance with certain aspects of the present disclosure. [Figure 6] FIG. 1 illustrates an example node in a networked environment in which a predictive model is used for channel estimation for beam failure detection, in accordance with certain aspects of the present disclosure. [Figure 7] FIG. 10 is a flow diagram illustrating example operations for wireless communication by a UE, in accordance with certain aspects of the present disclosure. [Figure 8] FIG. 10 is a flow diagram illustrating example operations for wireless communication by a UE, in accordance with certain aspects of the present disclosure. [Figure 9] FIG. 10 is a flow diagram illustrating example operations for wireless communication by a BS, in accordance with certain aspects of the present disclosure. [Figure 10A] FIG. 1 is a decision tree diagram illustrating example operations for wireless communication by a UE, in accordance with certain aspects of the present disclosure. [Figure 10B] FIG. 10 is another decision tree diagram illustrating example operations for wireless communication by a UE, in accordance with certain aspects of the present disclosure. [Figure 11A] FIG. 1 is a call flow diagram illustrating example signaling in accordance with certain aspects of the present disclosure. [Figure 11B] FIG. 1 is a call flow diagram illustrating example signaling in accordance with certain aspects of the present disclosure. [Figure 12] FIG. 1 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein, in accordance with aspects of the present disclosure. [Figure 13] FIG. 1 illustrates a communications device that may include various components configured to perform operations for the techniques disclosed herein, in accordance with aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0023] For ease of understanding, where possible, like reference numerals have been used to designate like elements common to the figures. It is contemplated that elements disclosed in one embodiment may be advantageously utilized in other embodiments without specific recitation.

[0024] Aspects of the present disclosure provide an apparatus, method, processing system, and computer-readable medium for beam fault detection (BFD) for a second radio frequency band based on measurements in a first radio frequency band. As used herein, a radio frequency band may also be referred to as a frequency band or a band.

[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., a sub-6 GHz band, sometimes referred to as FR1) may be simpler and more power-efficient than measurements in a different band (e.g., a millimeter wave (mmW) band, sometimes referred to as FR2, which may be in the frequency range of 24.25 to 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 hardware characteristics of the UE. Also, measurement overhead in the second band may be lower by using measurements from the first band.

[0026] In some examples, 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 FR4 to estimate the channel and perform BFD). In some examples, the UE may detect beam impairments for the second band based on estimates from RS measurements in the first band (e.g., without performing any RS measurements in the second band). For example, the UE may estimate (e.g., predict) a reference signal received power (RSRP) for a serving beam in the second band based on the RS measurements in the first band. The UE may detect / report a beam impairment based on whether the estimated RSRP for the second band is at or exceeds the BFD threshold for the second band, or whether the estimated RSRP is below the BFD threshold for the second band. Outside the margins of If the RSRP estimate for the serving beam in the second band is , beyond the margin within (e.g., approaching the BFD threshold for the second band), or for a threshold number of measurement instances. More than the margin If the BFD RSRP is within the BFD threshold for the second band, 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 and determine whether the second band is in a beam failure state. In some examples, the request for the RS is transmitted on a physical uplink control channel (PUCCH). If the RSRP is less than ... Outside the margins of If so, the UE determines that the serving beam in the second band is in a beam failure state. Is it in or approaching a beam obstruction When It can be determined.

[0027] The following description provides an example of BFD in a second band based on measurements in a first band in a communication system and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of the described elements without departing from the scope of the present disclosure. Various examples may omit, substitute, or add various procedures or components, as appropriate. For example, described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to 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 the aspects described herein. Furthermore, the scope of the present disclosure is intended to cover such apparatuses or methods practiced using other structure, functions, or structure and functions in addition to or other than the various aspects of the present disclosure described herein. It should be understood that any aspect of the present disclosure disclosed herein may be embodied by one or more elements of a claim. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

[0028] In general, any number of wireless networks may be deployed within a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, subcarrier, frequency channel, tone, subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs.

[0029] The techniques described herein may be used for various wireless networks and radio technologies. Although aspects may be described herein using terminology commonly associated with 3G, 4G, and / or New Radio (e.g., 5G NR) wireless technologies, aspects of the present disclosure may be applied in other generation-based communication systems.

[0030] New radio (e.g., 5G NR) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth, millimeter wave (mmW) targeting high carrier frequencies, massive machine type communications (MTC) targeting non-backward compatible MTC techniques, and / or mission critical targeting ultra-reliable low latency communications (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet their respective quality of service (QoS) requirements. Additionally, these services may coexist in 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 the DL may support up to eight transmit antennas with multi-layer DL transmission of up to eight streams and up to two streams per UE. Multi-layer transmission with up to two streams per UE may be supported. Multiple cell aggregation 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. For 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz to 7.125 GHz) and FR2 (24.25 GHz to 52.6 GHz). It should be understood that FR1 is often referred to (interchangeably) as the “sub-6 GHz” band in various documents and papers, although a portion of FR1 is above 6 GHz. Similar nomenclature issues may arise with respect to FR2, which is often referred to (interchangeably) as the “mmWave” band in documents and papers, even though it is distinct from the extremely high frequency (EHF) band (30 GHz to 300 GHz) identified by the International Telecommunications Union (ITU) as the “mmWave” band.

[0033] Frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR research has identified operating bands for these mid-band frequencies as the frequency range designation FR3 (7.125 GHz to 24.25 GHz). Frequency bands falling within FR3 can inherit FR1 and / or FR2 characteristics, thus effectively extending the features of FR1 and / or FR2 to mid-band 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, it should be understood that unless otherwise specified, terms such as "sub-6 GHz," when used herein, may broadly refer to frequencies that may be below 6 GHz, may be within FR1, or may include mid-band frequencies. Additionally, it should be understood that unless otherwise specified, terms such as "mm-Wave," when used herein, may broadly refer to frequencies that may include mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1 and / or FR5, or may be within the EHF band.

[0035] FIG. 1 illustrates an example wireless communication network 100 in which aspects 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 FIG. 1, the wireless communication network 100 may be in communication with a core network 132. The core network 132 may communicate with one or more base stations (BSs) 110a-z (each also referred to herein individually as a BS 110 or collectively as a BS 110), user equipments (UEs) 120a-y (each also referred to herein individually as a UE 120 or collectively as a UE 120), 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] The BSs 110 may provide communication coverage for a particular geographic area, which may be referred to as a “cell,” and may be fixed or may move according to the location of the mobile BS 110. In some examples, the BSs 110 may be interconnected to each other and / or to 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 connections, wireless connections, virtual networks, etc.) using any suitable transport network. In the example shown in FIG. 1, BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more cells.

[0037] The BS 110 communicates with the UEs 120 within the wireless communication network 100. The UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE 120 may be fixed or mobile. The wireless communication network 100 may include a relay station (e.g., relay station 110r), which may also be referred to as a relay, receives transmissions of data and / or other information from an upstream station (e.g., the BS 110a or the UE 120r), transmits transmissions of data and / or other information to a downstream station (e.g., the UE 120 or the BS 110), or relays transmissions between the UEs 120 to facilitate communication between the devices. The BS 110 and the UE 120 may communicate with each other using beams. As shown in FIG. 1, the BS 110a may communicate with the UE 120a using a serving beam 101 (e.g., from a set of beams).

[0038] The network controller 130 may be in communication with the set of BSs 110 and may provide coordination and control for these BSs 110 (e.g., via a backhaul). In an aspect, the network controller 130 may be in communication with a core network 132 (e.g., 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 aspects, the BS 110 and the UE 120 may be configured for BFD. As shown in FIG. 1, the BS 110a includes a BFD manager 112. As shown in FIG. 1, the UE 120a includes a BFD manager 122. The BFD manager 112 and / or the BFD manager 122 may be configured for BFD in a second band based on measurements in a first band, according to aspects of the disclosure.

[0040] FIG. 2 illustrates example components of a BS 110a and a UE 120a (eg, within the wireless communication network 100 of FIG. 1) that may be used to implement aspects of the present disclosure.

[0041] At the BS 110a, the transmit processor 220 may receive data from the data source 212 and control information from the controller / processor 240. The control information may be for a Physical Broadcast Channel (PBCH), a Physical Control Format Indicator Channel (PCFICH), a Physical Hybrid ARQ Indicator Channel (PHICH), a Physical Downlink Control Channel (PDCCH), a Group Common PDCCH (GC PDCCH), etc. The data may be for a Physical Downlink Shared Channel (PDSCH), etc. A Medium Access Control (MAC)-Control Element (MAC-CE) is a MAC layer communication structure that may be used to control command exchanges between wireless nodes. The MAC-CE may be carried within a shared channel, such as the Physical Downlink Shared Channel (PDSCH), the Physical Uplink Shared Channel (PUSCH), or the Physical Sidelink Shared Channel (PSSCH).

[0042] The processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a channel state information reference signal (CSI-RS). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​the data symbols, control symbols, and / or reference symbols, if applicable, and may provide output symbol streams to modulators (MODs) 232a through 232t within the transceiver. Each modulator may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 232a through 232t within the transceiver may be transmitted via antennas 234a through 234t, respectively.

[0043] At UE 120a, antennas 252a through 252r may receive downlink signals from BS 110a and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively, within the transceiver. Each demodulator may condition (e.g., filter, amplify, downconvert, and digitize) its respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all demodulators 254a through 254r within the transceiver, perform MIMO detection on the received symbols, if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols and provide decoded data for UE 120a to a data sink 260 and decoded control information to controller / processor 280.

[0044] On the uplink, at the UE 120a, a transmit processor 264 may receive and process data (e.g., for the Physical Uplink Shared Channel (PUSCH)) from a data source 262 and control information (e.g., for the Physical Uplink Control Channel (PUCCH)) from a controller / processor 280. The transmit processor 264 may also generate reference symbols for a reference signal (e.g., for a Sounding Reference Signal (SRS)). The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r within the transceiver (e.g., for SC-FDM, etc.), and transmitted to the BS 110a. At BS 110a, the uplink signal from UE 120a may be received by antenna 234, processed by a demodulator 232 within the transceiver, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by UE 120a. The receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to a controller / processor 240.

[0045] Memories 242 and 282 may store data and program codes for BS 110a and UE 120a, respectively. Scheduler 244 may schedule UEs for data transmission on the downlink and / or uplink.

[0046] The antennas 252, processors 266, 258, 264, and / or controller / processor 280 of the UE 120a and / or the antennas 234, processors 220, 230, 238, and / or controller / processor 240 of the BS 110a may be used to perform various techniques and methods described herein. For example, as shown in FIG. 2, the controller / processor 240 of the BS 110a includes a BFD manager 241, and the controller / processor 280 of the UE 120a includes a BFD manager 281. The BFD manager 241 and / or the BFD manager 281 may be configured for BFD for a second band based on measurements in a first band, according to aspects described herein. While shown in the controller / processor, other components of the UE 120a and the BS 110a may be used to perform the operations described herein.

[0047] NR may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and downlink. NR may support half-duplex operation using time division duplexing (TDD). OFDM and single-carrier frequency division multiplexing (SC-FDM) partition the system bandwidth into multiple orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. Modulation symbols are transmitted in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers may depend on the system bandwidth. The minimum resource allocation, called a resource block (RB), may be 12 contiguous subcarriers. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 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] FIG. 3 illustrates an example of a frame format 300 for NR. The transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be partitioned into 10 subframes, each of 1 ms, indexed from 0 to 9. Each subframe may include a variable number of slots (e.g., 1, 2, 4, 8, 16, ... slots) depending on the SCS. Each slot may include a variable number of symbol periods (e.g., 7 or 14 symbols) depending on the SCS. The symbol periods within each slot may be assigned an index. The subslot structure refers to transmission time intervals that are shorter in duration than a slot (e.g., 2, 3, or 4 symbols). Each symbol within a slot may indicate a link direction (e.g., DL, UL, or flexible) for data transmission, and the link direction may be dynamically switched per subframe. The link direction may be based on the slot format. Each slot may include DL / UL data as well as DL / UL control information.

[0049] In some systems, a UE may be configured for beam failure detection (BFD). For example, the UE may detect beam failure when channel estimation fails to meet a BFD threshold. The UE may be configured with a beam failure recovery procedure by radio resource control (RRC) signaling. The beam failure recovery procedure may include sending a beam recovery request message to a serving BS (e.g., gNB). For example, when a beam failure 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 beam failure by counting beam failure instance indications from lower layers to the UE. If beam failure recovery is reconfigured by higher layers during an ongoing random access procedure for beam failure recovery, the UE stops the ongoing random access procedure and initiates a new random access procedure using the new configuration.

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

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

[0052] In some examples, ML techniques involve training a model, such as a predictive model. The model may be used to predict (e.g., estimate) channel characteristics in a second band based on measurements in a first band. The model may be trained based on training data (e.g., training information), which 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 FIG. 4, measurements on a first band 403 in FR1 402 may be used to predict channel characteristics in a second band 405 in FR2 404. Alternatively, measurements in any of FR1 402, FR2 404, FR3 406, or FR4 408 (or another frequency range) may be used to predict channel characteristics in another one of the frequency ranges.

[0053] FIG. 5 illustrates an example networked environment 500 in which a predictive model 524 is used for channel estimation according to certain aspects of the present disclosure. As shown in FIG. 5, the networked environment 500 includes a node 520, a training system 530, and a training repository 515, communicatively coupled via a network 505. The node 520 may be a UE (e.g., UE 120a in wireless communication network 100). The network 505 may be a wireless network, such as wireless communication network 100, which may be a 5G NR network. While the training system 530, the node 520, and the training repository 515 are shown as separate components in FIG. 5, those skilled in the art should recognize that the training system 530, the node 520, and the 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 over a second band based on measurements in a first band. The predictive model 524 may be determined based on information in the training repository 515.

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

[0056] The predictive model training manager 532 may use information in the training repository 515 to determine a predictive model 524 (e.g., an algorithm) 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 the node 520, on a BS in the 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 the node 520. The training repository 515 may be a storage device, such as a memory. The training repository 515 may be located on the node 520, the training system 530, or another entity in the network 505. The training repository 515 may be in cloud storage. The training repository 515 may receive training information from the node 520, an entity in the network 505 (e.g., a BS or UE in the network 505), the cloud, or other sources.

[0057] The machine learning may use any suitable machine learning algorithm, in some non-limiting examples, the machine learning algorithm is a supervised learning algorithm, a deep learning algorithm, an artificial neural network algorithm, or other type of machine learning algorithm.

[0058] In some examples, machine learning (e.g., used by training system 530) is performed using a deep convolutional network (DCN). A DCN is a network of convolutional networks composed of additional pooling and normalization layers. DCNs have achieved state-of-the-art performance for many tasks. DCNs can be trained using supervised learning, in which both input and output targets are known for many examples and are used to modify the network weights using gradient descent. DCNs can be feedforward networks. Additionally, as described above, connections from neurons in a 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 DCNs can be exploited for high-speed processing. The computational burden of a DCN can be even lower than that of a similarly sized neural network, for example, including recurrent or feedback connections.

[0059] In some examples, machine learning (e.g., used by the training system 530) is performed using neural networks. Neural networks can be designed with various connectivity patterns. In feedforward networks, 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 built within successive layers of a feedforward network. Neural networks may have recurrent or feedback (also called top-down) connections. In recurrent connections, outputs from neurons in a given layer can be communicated to other neurons in the same layer. Recurrent architectures can be useful in recognizing patterns that span one or more of the input data chunks delivered sequentially to the neural network. Connections from neurons in a given layer to neurons in lower layers are called feedback (or top-down) connections. Networks with many feedback connections can be useful in helping recognize high-level concepts discriminate against specific low-level features of the input.

[0060] An artificial neural network, which may consist of an interconnected group of artificial neurons (e.g., neuron models), is a computational device or represents a method performed by a computational device. These neural networks may 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 in an artificial neural network may 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 the input data relates to the output data. For example, the input data for each node may be multiplied by the corresponding weight value and the products may be summed. The product sum may be adjusted by an optional bias, and an activation function may be applied to the result, resulting in an output signal or "output activation" for the node. The weight values ​​may initially be determined by an iterative flow of training data through the network (e.g., the weight values ​​are established during a training phase in which the network learns how to identify particular classes according to their typical input data characteristics).

[0061] Different types of artificial neural networks may be used to implement machine learning (e.g., as used by the training system 530), such as recurrent neural networks (RNNs), multi-layer perceptron (MLP) neural networks, and convolutional neural networks (CNNs). RNNs work by storing the output of a layer and feeding it back to the input to help predict the layer's outcome. In MLP neural networks, data can be fed into the input layer, and one or more hidden layers provide a level of abstraction to the data. Predictions can then be made to the output layer based on the abstract data. MLPs may be particularly well-suited for classification prediction problems when inputs are assigned to classes or labels. A convolutional neural network (CNN) is a type of feedforward artificial neural network. A convolutional neural network may include a collection of artificial neurons, each with a receptive field (e.g., a spatially localized region of input space) that collectively tile 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 a first layer of artificial neurons becomes the input to a second layer of artificial neurons, the output of the second layer of artificial neurons becomes the output of a third layer of artificial neurons, and so on. Convolutional neural networks can be trained to recognize hierarchies of features. Computation in convolutional neural network architectures can be distributed across a population of processing nodes, which can be organized into one or more computational chains. These multi-layer architectures can be trained one layer at a time and 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 (e.g., as described in more detail below, according to some aspects, the labels may be estimated RSRPs of serving beams in the second band). The predictive model training manager 532 may use these vectors to train the predictive model 524 for the node 520. As described above, the vectors may be associated with weights in the machine learning algorithm.

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

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

[0065] In some examples, the UE may detect a beam failure in the second band without performing any RS measurements in the second band. For example, if an RSRP estimate for a serving beam in the second band, determined based on RS measurements in the first band, is at or exceeds a BFD threshold for the second band, the UE may determine that no beam failure for the second band exists. However, if the channel estimate for the second band is less than the BFD threshold for the second band (e.g., when the RSRP estimate for the second band is less than the BFD threshold for a threshold number of measurement instances for the second band), the UE may determine a beam failure event for the second band.

[0066] In some instances, the estimated RSRP for the second band is less than the BFD threshold for the second band. Margin of When the estimated RSRP for the second band is within the BFD threshold (e.g., close to the BFD threshold for the second band), the UE may detect a beam failure in the second band by further performing RS measurements in the second band. In this case, the estimated RSRP for the second band exceeds the BFD threshold, but is still below the BFD threshold. Margin ofWhen the serving beam in the second band is within the beam failure detection state, the UE may request a BFD RS for the second band (e.g., an "on-demand BFD RS") and then measure and determine a beam failure detection event in the second band. The UE may transmit a request for a BFD RS on the 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 failure state. If the measured RSRP on the second band is less than the BFD threshold for the second band (e.g., when the measured RSRP for the second band is less than the BFD threshold for a threshold number of measurement instances for the second band), the UE may determine a beam failure event for the second band.

[0067] According to some aspects, a UE may perform beam failure detection in an upper 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 604 one or more RSs on a first band.

[0069] Measurements from the measurement manager 602 may be provided to a 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 in the first band. The input to the machine learning algorithm may include RS measurements in the first band. As shown in FIG. 6, in some examples, the measurement manager 602 measures 604 the RSs on the first band to provide measurement results 606, which may include reference signal received power (RSRP) measurements in the first band, UE positioning information (e.g., which may be used to learn beam directions), raw channel measurements, channel impulse response (CIR) measurements, angle-of-departure (AoD) measurements (e.g., AoD of the strongest multipath component (MPC)), delay profiles of the strongest MPCs, and / or other measurements in the first band and / or other inputs that may be used by the machine learning algorithm to estimate channel characteristics of the second band and / or predict RSRP for a beam (e.g., a serving beam) in the second band.

[0070] In some examples, the output of the machine learning algorithm is a predicted RSRP value for a beam in the second band. As shown in FIG. 6, the prediction model 524 may be configured to estimate 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, and the BS may use those measurements to estimate channel characteristics of the second band. The BS may then provide the estimate to the UE, and / or the BS may detect beam obstructions to the serving beam in the second band.

[0071] In some examples, the machine learning algorithm is trained with historical training data including measurements in a first band (including one or more previous measurements of the inputs described above), previous measurements of channel characteristics of a second band, and / or previous measurements in the 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 for a variety of different environments, and the predictive model used may be based on the current environment.

[0072] According to some aspects, the BFD manager 610 determines beams on the second band that are at or near failure using channel characteristics for the second band (e.g., RSRP for the serving beam) estimated from RS measurements on the first band using a machine learning algorithm. For example, the BFD manager 610 may be configured to compare 612 the 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 in which 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 in which 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 beam failure for 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 exceed the threshold number for the second band.

[0073] In some examples, if the BFD manager 610 determines that the beam is in a failed state (when the estimated RSRP value for the second band is less than the BFD threshold for the second band for at or above a threshold number of measurement instances), the BFD manager 610 may initiate a beam failure recovery (BFR) in 616, for example, by sending a beam failure recovery (BFR) message to the BS. In this case, the node 520 may not 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 failed state.

[0074] In some examples, the BFD manager 610 may request the network (e.g., BS) to transmit an RS on a second band based on measurements on a first band. This may be referred to as an "on-demand" BFD RS. The BFD manager 610 may send the request on the PUCCH. For example, if the estimated RSRP is near or approaches the BFD threshold for the second band (e.g., exceeds the BFD threshold and is below the BFD threshold), the BFD manager 610 may send the request on the PUCCH. Margin range of When the beam is in a failed state (e.g., within the range of the BFD threshold for the second band), the BFD manager 610 may send a request for a BFD RS on the second band at 614. The node 520 may then measure the RS on the second band, determine an actual RSRP value for the second band, and determine whether the beam for the second band is in a failed state based on the actual RSRP measured on the RS on the second band. When the BFD manager 610 determines that the beam is in a failed state based on the actual RSRP, the BFD manager 610 may initiate a BFR at 616. In some examples, if the actual RSRP is at or exceeds the BFD threshold for the second band, the BFD manager 610 determines that the beam is not in a failed state and does not initiate a BFR. In some examples, if the estimated RSRP is not close to the BFD threshold for the second band (e.g., above the BFD threshold), the BFD manager 610 may initiate a BFR. The margin of If the difference exceeds the threshold, the BFD manager 610 can determine that the beam is not close to an obstacle and does not need to request an RS on the second band and does not initiate a BFR.

[0075] Thus, node 520 may measure on a first band, which may be more power efficient than measurements on a second band. Additionally, the signaling overhead for the reference signal in the second band may be lower by replacing the reference signal with data, because node 520 may rely on measuring an "on-demand" reference signal on the second band, thereby having efficient signaling overhead and saving power.

[0076] 7 is a flow diagram illustrating example operations 700 for wireless communication in accordance with certain aspects of the present disclosure. The operations 700 may be performed, for example, by a UE (e.g., UE 120a in wireless communication network 100, etc.). The operations 700 may be implemented as software components executed and operated on one or more processors (e.g., controller / processor 280 of FIG. 2). Furthermore, transmission and reception of signals by the UE in operations 600 may be enabled, for example, by one or more antennas (e.g., antenna 252 of FIG. 2). In some aspects, 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 acquire and / or output signals.

[0077] The operations 700 may begin at 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 a 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] At 710, the UE determines a BFD for the second radio frequency band based at least in part on the measurements of one or more RSs on the first radio frequency band. In some examples, determining the BFD for the second radio frequency band includes estimating one or more channel parameters of the second radio frequency band using a machine learning (ML) algorithm that uses the measurements of the one or more RSs on the first radio frequency band as input. In some examples, the estimated one or more channel parameters include estimated one or more RSRP values.

[0079] In some examples, determining the BFD for the second radio frequency band includes reporting the BFD (e.g., initiating beam failure recovery) when the estimated RSRP for a serving beam of the second radio frequency band is less than a beam failure threshold for the second radio frequency band for a measurement instance that is at or exceeds a threshold number for the second band. In some examples, determining the BFD for the second radio frequency band includes reporting the BFD (e.g., initiating beam failure recovery) when the estimated RSRP for a serving beam of the second radio frequency band is less than a beam failure threshold for the second radio frequency band for a measurement instance that is at or exceeds a BFD threshold for the second radio frequency band. Margin ofWhen the measurement instance is within a threshold number for the second band, requesting one or more RSs on the second radio frequency band, measuring the one or more RSs on the second radio frequency band, and reporting a BFD (e.g., and / or initiating a beam failure recovery procedure) for the second radio frequency band based on the measurements of the one or more RSs on the second radio frequency band for measurement instances that are at or exceed a threshold number for the second band.

[0080] 8 is a flow diagram illustrating example operations 800 for wireless communication in accordance with certain aspects of the present disclosure. The operations 800 may be performed, for example, by a UE (e.g., UE 120a in wireless communication network 100, etc.). The operations 800 may be implemented as software components executed and operated on one or more processors (e.g., controller / processor 280 of FIG. 2). Furthermore, transmission and reception of signals by the UE in operations 800 may be enabled, for example, by one or more antennas (e.g., antenna 252 of FIG. 2). In some aspects, 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 acquire and / or output signals.

[0081] The operations 800 may begin, at 805, by receiving one or more RSs over a first radio frequency band.

[0082] At 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] At 815, the UE may perform BFD for the second radio frequency band based at least in part on one or more measurements of one or more RSs on the first radio frequency band. The first radio frequency band may be in a lower frequency range (e.g., within a 6 GHz radio frequency range) than the second radio frequency band (e.g., within a mmW radio frequency range). At 820, the UE may estimate one or more channel parameters (e.g., RSRP) of the second radio frequency band using an ML algorithm that uses as input the one or more measurements of the one or more RSs on the first radio frequency band. At 825, the UE compares the estimated one or more channel parameters of the second radio frequency band with 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 with 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 the estimated one or more channel parameters for the second radio frequency band are less than the channel parameter threshold for the second radio frequency band with a threshold number of measurement instances for the second radio frequency band.

[0084] The UE may detect beam obstruction for the second radio frequency band when the estimated one or more channel parameters of the second radio frequency band are less than a channel parameter threshold for the second radio frequency band for a measurement instance that is at or exceeds the threshold for the second radio frequency band. At 830, the estimated one or more channel parameters of the second radio frequency band are detected as being less than a predefined value of the BFD threshold for the second radio frequency band. MarginsWhen the second radio frequency band is within the predetermined range, the UE may request one or more RSs on the second radio frequency band. The UE may measure one or more RSs (e.g., on-demand BFD RSs) on the second radio frequency band, compare the one or more measurements of the 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 in which the measurements of the one or more RSs on the second radio frequency band are less than the channel parameter threshold for the second radio frequency band.

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

[0086] 9 is a flow diagram illustrating example operations 900 for wireless communication according to some aspects of the present disclosure. The operations 900 may be performed, for example, by a BS (e.g., BS 110a in wireless communication network 100, etc.). The operations 900 may be complementary operations by the BS to operations 900 performed by a UE. The operations 900 may be implemented as software components executed and operated on one or more processors (e.g., controller / processor 240 of FIG. 2). Furthermore, the transmission and reception of signals by the BS in the operations 900 may be enabled, for example, by one or more antennas (e.g., antenna 234 of FIG. 2). In some aspects, the transmission and / or reception of signals by the BS may be implemented via a bus interface of one or more processors (e.g., controller / processor 240) that acquires and / or outputs the signals.

[0087] The operations 900 may begin, at 905, by transmitting a first one or more RSs to a UE on a first radio frequency band.

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

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

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

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

[0092] 10A is a decision tree diagram illustrating example operations 1000a for wireless communication by a UE according to certain aspects of the present disclosure. As shown in FIG. 10A, the UE measures one or more RSs on a first band at 1002. At 1004, the UE estimates the RSRP of a serving node on a second band based on measurements in the first band (e.g., the measurements performed at 1002). At 1006, the UE compares the estimated RSRP for the second band with a BFD threshold for the second band. If the estimated RSRP for the second band is at or exceeds the BFD threshold for the second band, the UE may determine that no beam obstruction exists at 1022 (and may return to block 1002 and measure the RSs on the first band). If the estimated RSRP for the second band is less than the BFD threshold for the second band, the UE may initiate BFR for the second band at 1012. For example, the UE may count measurement instances in which the estimated RSRP for the second band is less than the BFD threshold for the second band. When the number of measurement instances in which 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. When the number of measurement instances in which the estimated RSRP for the second band is at or exceeds the BFD threshold for the second band is at or exceeds the threshold number of measurement instances, the UE may initiate BFR in block 1012.

[0093] 10B illustrates another decision tree diagram illustrating example operations 1000b for wireless communication by a UE in accordance with certain aspects of the present disclosure. As shown in FIG. 10B, the UE may determine at 1006b whether the estimated RSRP is greater than or equal to the BFD threshold for the second band. Margin of The UE may further check whether the estimated RSRP for the second band is within a BFD threshold for the second band, at 1006b. The margin ofIf so, the UE may determine that no beam obstruction exists, at 1024b (and may return to block 1002 and measure RS on the first band). On the other hand, if the UE determines that the estimated RSRP exceeds the BFD threshold and measures the BFD threshold for the second band, at 1006b, Margin of If the UE determines that the RSRP is within the BFD threshold, the UE may request one or more BFD RSs (e.g., on-demand BFD RSs) for the second band at 1014. At 1016, the UE measures one or more BFD RSs on the second band. The UE may determine an actual RSRP of the second band based on the measurements of the BFD RSs on the second band. At 1018, the UE determines whether the actual measured RSRP for the second band is less than a BFD threshold for the second band. If the RSRP is not less than the BFD threshold, the UE may determine at 1022 that there is no beam failure for the second band (e.g., for the serving cell for the second band). If the RSRP is less than the BFD threshold, the UE may initiate beam failure recovery for the second band at 1020. For example, the UE may count measurement instances in which the actual measured RSRP for the second band is less than the BFD threshold for the second band. When 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 at or exceeds the BFD threshold for the second band is at or exceeds the threshold number of measurement instances, the UE initiates BFR at 1020.

[0094] 11A is a call flow illustrating example signaling 1100a according to some aspects of the present disclosure. At 1102, a BS transmits one or more RSs on a first band to a UE. At 1104, the UE measures the one or more RSs on the first band. In some examples, no beam failure event has occurred. In this case, at 1106a, the UE estimates one or more channel characteristics on a second band, and the estimated channel characteristics are at or exceed a BFD threshold. At 1108a, the UE may determine that there are no beam failures on the second band. In some examples, a beam failure event has occurred. In this case, at 1106b, the UE estimates one or more channel characteristics on the second band, and the estimated channel characteristics are less than a BFD threshold. At 1108b, the UE may initiate beam failure recovery on the second band when the number of measurement instances in which the estimated channel characteristics are less than the BFD threshold is at or exceeds a threshold number of measurement instances.

[0095] FIG. 11B is a call flow illustrating example signaling 1100b according to some aspects of the present disclosure. At 1102, a BS transmits one or more RSs on a first band to a UE. At 1104, the UE measures one or more RSs on the first band. In some examples, a beam may be close to an obstruction. At 1106c, the UE estimates one or more channel characteristics on a second band, and the estimated channel characteristics are within a BFD threshold. At 1108c, the UE requests one or more RSs on the second band. At 1110, the BS transmits the requested one or more RSs on the second band to the UE. At 1112, the UE measures one or more RSs on the second band. In some examples, a beam obstruction event has not occurred. At 1114a, the measured channel characteristics are at or exceed the BFD threshold, and at 1116a, the UE may determine that there is no beam obstruction on the second band. In some examples, a beam obstruction event has occurred. At 1114b, the measured channel characteristics are less than the BFD threshold, and at 1116b, when the number of measurement instances in which the estimated channel characteristics are less than the BFD threshold is at or exceeds a threshold number of measurement instances, the UE may initiate beam failure recovery on the second band.

[0096] 12 shows a communications device 1200 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as those shown in FIG. 7 and / or FIG. 8. The communications device 1200 includes a processing system 1202 coupled to a transceiver 1208 (e.g., a transmitter and / or a receiver). The transceiver 1208 is configured to transmit and receive signals for the communications device 1200 via an antenna 1210, such as various signals as described herein. The processing system 1202 may be configured to perform processing functions for the communications device 1200, including processing signals received by and / or to be transmitted by the communications device 1200.

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

[0098] 13 shows a communications device 1300 that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as those illustrated in FIG. 9. The communications device 1300 includes a processing system 1302 coupled to a transceiver 1308 (e.g., a transmitter and / or a receiver). The transceiver 1308 is configured to transmit and receive signals for the communications device 1300 via an antenna 1310, such as various signals as described herein. The processing system 1302 may be configured to perform processing functions for the communications device 1300, including processing signals received by and / or to be transmitted by the communications 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 aspects, 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 FIG. 9 or other operations for performing various techniques described herein with respect to BFD over a second band based on measurements over a first band. In some aspects, the computer-readable medium / memory 1312 stores code 1314 for transmitting a first one or more RSs to a UE on a first radio frequency band, code 1316 for receiving a request from the UE for a second one or more RSs on a second radio frequency band in response to the first one or more RSs on the first radio frequency band, code 1318 for transmitting the second one or more RSs on the second radio frequency band to the UE, and / or code 1320 for receiving a beam failure recovery request message for the second radio frequency band from the UE, according to aspects of the present disclosure. In some aspects, 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 a first one or more RSs to the UE on a first radio frequency band, a circuit 1324 for receiving a request from the UE to transmit a second one or more RSs on a second radio frequency band in response to the first one or more RSs on the first radio frequency band, a circuit 1326 for transmitting the second one or more RSs on the second radio frequency band to the UE, and / or a circuit 1328 for receiving a beam failure recovery request message for the second radio frequency band from the UE. Exemplary Embodiments

[0100] Example implementations are described in the following numbered clauses.

[0101] Aspect 1. A method for wireless communication by a user equipment (UE), the method including: receiving one or more reference signals (RS) on a first radio frequency band; and initiating a beam failure recovery procedure for a second radio frequency band based at least in part on the one or more RSs received on the first radio frequency band.

[0102] Aspect 2. The method of aspect 1, further including: measuring one or more RSs on the first radio frequency band; and performing 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.

[0103] Aspect 3. The method of aspect 2, wherein performing BFD for the second radio frequency band includes estimating one or more channel parameters of the second radio frequency band using a machine learning (ML) algorithm that uses as input one or more measurements of one or more RSs on the first radio frequency band; and comparing the estimated one or more channel parameters of the second radio frequency band to a BFD threshold for the second radio frequency band.

[0104] Aspect 4. The method of aspect 3, wherein performing BFD for the second radio frequency band includes detecting a beam obstruction for the 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 at or above a threshold number of measurement instances.

[0105] Aspect 5. The step of performing BFD for the second radio frequency band includes determining whether the estimated one or more channel parameters of the second radio frequency band are greater than a predefined BFD threshold for the second radio frequency band. MarginsWhen the received signal is within a predetermined range, the method of any one of aspects 3 to 4 includes requesting one or more RSs on the second radio frequency band; measuring the one or more RSs on the second radio frequency band; and comparing the one or more measurements of the one or more RSs on the second radio frequency band to a BFD threshold for the second radio frequency band.

[0106] Aspect 6. The method of aspect 5, wherein the requesting one or more 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.

[0107]

[0023] Aspect 7. The method of any one of aspects 2 to 6, wherein the one or more measurements on the 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 Departure (AoD) measurements, one or more delay measurements, or a combination thereof.

[0108]

[0013] Aspect 8. The method of any one of aspects 2 to 7, wherein the estimated one or more channel parameters include estimated one or more reference signal received power (RSRP) values.

[0109]

[0016] Embodiment 9. The method of any one of embodiments 1 to 8, wherein the first radio frequency band is within a sub-6 GHz radio frequency range and the second radio frequency band is within a millimeter wave (mmW) radio frequency range.

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

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

[0112]

[0023] Embodiment 12. The method of embodiment 10 or embodiment 11, wherein the first radio frequency band is within a sub-6 GHz radio frequency range and the second radio frequency band is within a millimeter-wave (mmW) radio frequency range.

[0113] Aspect 13. The method of any one of Aspects 10 to 12, wherein receiving a request from the UE to transmit the second one or more RSs on the second radio frequency band includes receiving the request on a physical uplink control channel (PUCCH).

[0114] Aspect 14. The method of any one of Aspects 10 to 13, wherein receiving a request from the UE to transmit the second one or more RSs on the second radio frequency band includes receiving a request from the UE to transmit one or more on-demand beam failure detection (BFD) RSs on the second radio frequency band.

[0115] Embodiment 15. An apparatus comprising means for performing the method of any one of embodiments 1 to 14.

[0116] Aspect 16. An apparatus comprising at least one processor and a memory coupled to the at least one processor, the memory comprising code executable by the at least one processor to cause the apparatus to perform the method of any one of aspects 1 to 14.

[0117] Aspect 17. A computer-readable medium having stored thereon computer-executable code for wireless communication that, when executed by at least one processor, causes an apparatus to perform the method of any one of aspects 1 to 14. Additional Considerations

[0118] The techniques described herein may be used for various wireless communication technologies, such as 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. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, and the like. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers the IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA network may implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are parts 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 described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). NR is a new wireless communications 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 this coverage area, depending on the context in which the term is used. In an NR system, the terms "cell" and BS, next-generation NodeB (gNB or gNodeB), access point (AP), distributed unit (DU), carrier, or transmit reception point (TRP) may be used interchangeably. A BS may provide communication coverage for a macrocell, picocell, femtocell, and / or other types of cell. A macrocell may cover a relatively large geographic area (e.g., a few kilometers in radius) and may allow unrestricted access by UEs with service subscriptions. A picocell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femtocell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femtocell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, etc.). A BS for a macro cell may be referred to as a macro BS, a BS for a pico cell may be referred to as a pico BS, and a BS for a femto cell may be referred to as a femto BS or a home BS.

[0120] A UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smartphone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or equipment, biometric sensor / device, wearable device such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or vehicle sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate over a wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC UEs and eMTC UEs include, for example, a robot, a drone, a remote device, a sensor, a meter, a monitor, a location tag, etc. that may communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0121] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication between some or all devices and equipment within its coverage area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entities use the resources allocated by the scheduling entity. A base station is not the only entity that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and schedule resources for one or more subordinate entities (e.g., one or more other UEs), and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In one example of a mesh network, UEs may communicate directly with each other in addition to communicating with the scheduling entity.

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

[0123] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including single members. As an 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 multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other permutation of a, b, and c).

[0124] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, database, or another data structure), ascertaining, etc. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. Also, "determining" may include resolving, selecting, choosing, establishing, etc.

[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 those skilled in the art, and the general principles defined herein may be applied to other embodiments. Accordingly, the claims are not limited to the embodiments set forth herein but are to be accorded the full scope consistent with the language of the claims, and references to elements in the singular shall mean "one and only one," rather than "one or more," unless expressly stated otherwise. Unless expressly stated otherwise, the term "some" refers to one or more. All structural and functional equivalents of the elements of the various embodiments described throughout this disclosure that are known or later become known to those skilled in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be made public, regardless of whether such disclosure is expressly recited in the claims. No element of a claim is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase "means for," or, in the case of a method claim, the phrase "step for."

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

[0127] The various example logic blocks, modules, and circuits described in connection with this disclosure may be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0128] When implemented in hardware, an exemplary hardware configuration may comprise a processing system within a wireless node. The processing system may be implemented using a bus architecture. The bus may include any number of interconnected buses and bridges, depending on the particular application of the processing system and overall design constraints. The bus may link various circuits together, including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter to the processing system via the bus, among other things. The network adapter may be used to implement PHY layer signal processing functions. In the case of a user terminal (see FIG. 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, power management circuits, etc., which are well known in the art and therefore will not be described further. The processor may be implemented using one or more general-purpose and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits capable of executing software. Those skilled in the art will recognize how to best implement the described functionality for a processing system depending on the particular application and the overall design constraints imposed on the overall system.

[0129] If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Software shall be broadly construed to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media includes both computer storage media and communication media, including any medium that facilitates transfer of a computer program from one place to another. A processor may be responsible for general processing, including managing a bus and executing software modules stored on the machine-readable storage medium. The computer-readable storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor. By way of example, the machine-readable medium may include a transmission line, a carrier wave modulated by data, and / or a computer-readable storage medium having instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through a bus interface. Alternatively or additionally, the machine-readable medium, or any portion thereof, may be integrated into the processor, such as may be a cache and / or a general-purpose register file. Examples of machine-readable storage media may include, by way of 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 medium, or any combination thereof. The machine-readable medium may be embodied in a computer program product.

[0130] A software module may comprise a single instruction or many instructions and may be distributed across several different code segments, among different programs, and across multiple storage media. A computer-readable medium may comprise several software modules. A software module contains instructions that, when executed by a device such as a processor, cause a processing system to perform various functions. A software module may include a transmitting module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. As an example, a software module may be loaded into RAM from a hard drive when a trigger event occurs. During execution of a software module, a 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 for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

[0131] Also, any connection is properly termed 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, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. As used herein, disk and disc include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically while discs reproduce data optically using lasers. Thus, in some aspects computer-readable medium may comprise non-transitory computer-readable medium (e.g., tangible media). In addition, for other aspects, computer-readable medium may comprise transitory computer-readable medium (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

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

[0133] Furthermore, it should be appreciated that modules and / or other suitable means for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by a user terminal and / or base station, where applicable. For example, such a device 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., a physical storage medium such as RAM, ROM, a compact disc (CD), or a floppy disk) such that the user terminal and / or base station may obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device may be utilized.

[0134] It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims. [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 Controller 132 Core Network 134 Core Network Nodes 212 Data Sources 220 Transmit Processor, Processor 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 Sink 240 Controller / Processor, Processor 241 BFD Manager 242 memory 244 Scheduler 252 Antenna 252a~252r Antenna 254a~254r demodulator 256 MIMO detector 258 Receive Processor, Processor 260 Data Sink 262 Data Sources 264 Transmit Processor, Processor 266 processors 280 Controller / Processor 281 BFD Manager 282 memory 300 Frame Format 402 FR1 403 First Band 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 Model 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 medium / memory 1214 receiving code 1216 Code for measuring 1218 Code to run 1220 Code for Estimation 1222 Code to compare 1224 Request Code 1226 code to get started 1228 Receiving circuit 1230 Measuring Circuit 1232 Circuit for running 1234 Circuit for Estimation 1236 Circuit for comparison 1238 Circuit for requesting 1240 Starting Circuit 1300 Communication Devices 1302 Processing System 1304 processor 1306 Bus 1308 Transceiver 1310 Antenna 1312 Computer-readable medium / memory 1314 code for transmitting the first one or more RSs to the UE on the first radio frequency band. 1316 code for receiving, from the UE, a request to transmit a second one or more RSs on a second radio frequency band in response to the first one or more RSs on the first radio frequency band 1318 code for transmitting a second one or more RSs to a UE on a second radio frequency band 1320 code for receiving from the UE a beam obstruction recovery request message for a second radio frequency band 1322 a circuit for transmitting the first one or more RSs to the UE on the first radio frequency band. 1324 circuit for receiving a request from the UE to transmit a second one or more RSs on a second radio frequency band in response to the first one or more RSs on the first radio frequency band. 1326 circuitry for transmitting a second one or more RSs to the UE on a second radio frequency band. 1328 a circuit for receiving a beam obstruction recovery request message for the second radio frequency band from the UE.

Claims

1. 1. A method for wireless communication by a user equipment (UE), comprising: receiving a first one or more reference signals (RS) over a first radio frequency band; measuring the first one or more RSs on the first radio frequency band; estimating one or more channel parameters of a second radio frequency band based on one or more measurements of the first one or more 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 to a BFD threshold for the second radio frequency band; determining that there is no beam obstruction 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 comprising:

2. performing BFD for the second radio frequency band, 10. The method of claim 1, comprising estimating one or more channel parameters of the second radio frequency band using a machine learning (ML) algorithm that uses as input the one or more measurements of the first one or more RSs on the first radio frequency band.

3. performing BFD for the second radio frequency band, detecting beam obstruction for the second radio frequency band when the estimated one or more channel parameters for the second radio frequency band are less than the BFD threshold for the second radio frequency band for a threshold number of measurement instances or more.

2. The method of claim 1, comprising:

4. performing BFD for the second radio frequency band, 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; measuring the second one or more RSs on the second radio frequency band; comparing one or more measurements of the second one or more RSs on the second radio frequency band to the BFD threshold for the second radio frequency band; 2. The method of claim 1, comprising:

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

6. 10. The method of claim 1, wherein the one or more measurements on the 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 Departure (AoD) measurements, one or more delay measurements, or a combination thereof.

7. 10. The method of claim 1, wherein the estimated one or more channel parameters include estimated one or more reference signal received power (RSRP) values.

8. 2. The method of claim 1, wherein the first radio frequency band is in a sub-6 GHz radio frequency range and the second radio frequency band is in a millimeter wave (mmW) radio frequency range.

9. 1. An apparatus for wireless communication, comprising: means for receiving a first one or more reference signals (RS) over a first radio frequency band; measuring the first one or more RSs on the first radio frequency band; estimating one or more channel parameters of a second radio frequency band based on one or more measurements of the first one or more 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 to a BFD threshold for the second radio frequency band; determining that there is no beam obstruction in the second radio frequency band in response to the estimated one or more channel parameters exceeding the BFD threshold; and 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. Device.

10. means for estimating one or more channel parameters of the second radio frequency band using a machine learning (ML) algorithm that uses as input the one or more measurements of the first one or more RSs on the first radio frequency band.

10. The apparatus of claim 9.

11. and means for detecting beam obstruction 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 the second radio frequency band for a threshold number of measurement instances or more.

10. The apparatus of claim 9.

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; and means for measuring the second one or more RSs on the second radio frequency band; and 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.

10. The apparatus of claim 9.

13. and 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.

13. The apparatus of claim 12.

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