WO2022052075A1

WO2022052075A1 - Reusing a transmit-receive beam pair after a beam failure

Info

Publication number: WO2022052075A1
Application number: PCT/CN2020/114957
Authority: WO
Inventors: Nan Zhang
Original assignee: Qualcomm Incorporated
Priority date: 2020-09-14
Filing date: 2020-09-14
Publication date: 2022-03-17

Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may detect a beam failure of a transmit-receive (Tx-Rx) beam pair used by the UE to communicate with a base station. The UE may transmit a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time. Numerous other aspects are provided.

Description

REUSING A TRANSMIT-RECEIVE BEAM PAIR AFTER A BEAM FAILURE

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for reusing a transmit-receive beam pair after a beam failure.

BACKGROUND

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical 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, and/or the like) . Examples of such multiple-access technologies include 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, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE) . LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP) .

A wireless network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs) . A user equipment (UE) may communicate with a base station (BS) via the downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, an access point (AP) , a radio head, a transmit receive point (TRP) , a New Radio (NR) BS, a 5G Node B, and/or the like.

The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate on a municipal, national, regional, and even global level. New Radio (NR) , which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP) . NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL) , using CP-OFDM and/or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM) ) on the uplink (UL) , as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. As the demand for mobile broadband access continues to increase, further improvements in LTE, NR, and other radio access technologies remain useful.

SUMMARY

In some aspects, a method of wireless communication performed by a user equipment (UE) includes detecting a beam failure of a transmit-receive (Tx-Rx) beam pair used by the UE to communicate with a base station; and transmitting a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time.

In some aspects, a UE for wireless communication includes a memory; and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: detect a beam failure of a Tx-Rx beam pair used by the UE to communicate with a base station; and transmit a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time.

In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a UE, cause the UE to: detect a beam failure of a Tx-Rx beam pair used by the UE to communicate with a base station; and transmit a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time.

In some aspects, an apparatus for wireless communication includes means for detecting a beam failure of a Tx-Rx beam pair used by the apparatus to communicate with a base station; and means for transmitting a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the drawings and specification.

The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. The same reference numbers in different drawings may identify the same or similar elements.

Fig. 1 is a diagram illustrating an example of a wireless network, in accordance with various aspects of the present disclosure.

Fig. 2 is a diagram illustrating an example of a base station in communication with a UE in a wireless network, in accordance with various aspects of the present disclosure.

Fig. 3 is a diagram illustrating an example of a four-step random access procedure, in accordance with various aspects of the present disclosure.

Fig. 4 is a diagram illustrating an example of a two-step random access procedure, in accordance with various aspects of the present disclosure.

Fig. 5 is a diagram illustrating an example associated with reusing a transmit-receive beam pair after a beam failure, in accordance with various aspects of the present disclosure.

Fig. 6 is a diagram illustrating an example process associated with reusing a transmit-receive beam pair after a beam failure, in accordance with various aspects of the present disclosure.

Fig. 7 is a block diagram of an example apparatus for wireless communication, in accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein, one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

Several aspects of telecommunication systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, and/or the like (collectively referred to as “elements” ) . These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

It should be noted that while aspects may be described herein using terminology commonly associated with a 5G or NR radio access technology (RAT) , aspects of the present disclosure can be applied to other RATs, such as a 3G RAT, a 4G RAT, and/or a RAT subsequent to 5G (e.g., 6G) .

Fig. 1 is a diagram illustrating an example of a wireless network 100, in accordance with various aspects of the present disclosure. The wireless network 100 may be or may include elements of a 5G (NR) network, an LTE network, and/or the like. The wireless network 100 may include a number of base stations 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A base station (BS) is an entity that communicates with user equipment (UEs) and may also be referred to as an NR BS, a Node B, a gNB, a 5G node B (NB) , an access point, a transmit receive point (TRP) , and/or the like. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a BS and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a closed subscriber group (CSG) ) . 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. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in Fig. 1, a BS 110a may be a macro BS for a macro cell 102a, a BS 110b may be a pico BS for a pico cell 102b, and a BS 110c may be a femto BS for a femto cell 102c. A BS may support one or multiple (e.g., three) cells. The terms “eNB” , “base station” , “NR BS” , “gNB” , “TRP” , “AP” , “node B” , “5G NB” , and “cell” may be used interchangeably herein.

In some aspects, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some aspects, the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces such as a direct physical connection, a virtual network, and/or the like using any suitable transport network.

Wireless network 100 may also include relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS) . A relay station may also be a UE that can relay transmissions for other UEs. In the example shown in Fig. 1, a relay BS 110d may communicate with macro BS 110a and a UE 120d in order to facilitate communication between BS 110a and UE 120d. A relay BS may also be referred to as a relay station, a relay base station, a relay, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/or the like. These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in wireless network 100. For example, macro BSs may have a high transmit power level (e.g., 5 to 40 watts) whereas pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 watts) .

A network controller 130 may couple to a set of BSs and may provide coordination and control for these BSs. Network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with one another, e.g., directly or indirectly via a wireless or wireline backhaul.

UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, a terminal, a mobile station, a subscriber unit, a station, and/or the like. A UE may be a cellular phone (e.g., a smart phone) , a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet) ) , an entertainment device (e.g., a music or video device, or a satellite radio) , a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, and/or the like, that may communicate with a base station, another device (e.g., 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 Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, and/or may be implemented as NB-IoT (narrowband internet of things) devices. Some UEs may be considered a Customer Premises Equipment (CPE) . UE 120 may be included inside a housing that houses components of UE 120, such as processor components, memory components, and/or the like. In some aspects, the processor components and the memory components may be coupled together. For example, the processor components (e.g., one or more processors) and the memory components (e.g., a memory) may be operatively coupled, communicatively coupled, electronically coupled, electrically coupled, and/or the like.

In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular RAT and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, and/or the like. A frequency may also be referred to as a carrier, a frequency channel, and/or the like. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with one another) . For example, the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol, a vehicle-to-infrastructure (V2I) protocol, and/or the like) , a mesh network, and/or the like. In this case, the UE 120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station 110.

Devices of wireless network 100 may communicate using the electromagnetic spectrum, which may be subdivided based on frequency or wavelength into various classes, bands, channels, and/or the like. For example, devices of wireless network 100 may communicate using an operating band having a first frequency range (FR1) , which may span from 410 MHz to 7.125 GHz, and/or may communicate using an operating band having a second frequency range (FR2) , which may span from 24.25 GHz to 52.6 GHz. The frequencies between FR1 and FR2 are sometimes referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as a “sub-6 GHz” band. Similarly, FR2 is often referred to as a “millimeter wave” band despite being different from the extremely high frequency (EHF) band (30 GHz –300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band. Thus, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like, if used herein, may broadly represent frequencies less than 6 GHz, frequencies within FR1, and/or mid-band frequencies (e.g., greater than 7.125 GHz) . Similarly, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like, if used herein, may broadly represent frequencies within the EHF band, frequencies within FR2, and/or mid-band frequencies (e.g., less than 24.25 GHz) . It is contemplated that the frequencies included in FR1 and FR2 may be modified, and techniques described herein are applicable to those modified frequency ranges.

As indicated above, Fig. 1 is provided as an example. Other examples may differ from what is described with regard to Fig. 1.

Fig. 2 is a diagram illustrating an example 200 of a base station 110 in communication with a UE 120 in a wireless network 100, in accordance with various aspects of the present disclosure. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T ≥ 1 and R ≥ 1.

At base station 110, a transmit processor 220 may receive data from a data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS (s) selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI) and/or the like) and control information (e.g., CQI requests, grants, upper layer signaling, and/or the like) and provide overhead symbols and control symbols. Transmit processor 220 may also generate reference symbols for reference signals (e.g., a cell-specific reference signal (CRS) , a demodulation reference signal (DMRS) , and/or the like) and synchronization signals (e.g., the primary synchronization signal (PSS) and secondary synchronization signal (SSS) ) . A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM and/or the like) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively.

At UE 120, antennas 252a through 252r may receive the downlink signals from base station 110 and/or other base stations and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM and/or the like) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller/processor 280. The term "controller/processor" may refer to one or more controllers, one or more processors, or a combination thereof. A channel processor may determine reference signal received power (RSRP) , received signal strength indicator (RSSI) , reference signal received quality (RSRQ) , channel quality indicator (CQI) , and/or the like. In some aspects, one or more components of UE 120 may be included in a housing 284.

Network controller 130 may include communication unit 294, controller/processor 290, and memory 292. Network controller 130 may include, for example, one or more devices in a core network. Network controller 130 may communicate with base station 110 via communication unit 294.

On the uplink, at UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports that include RSRP, RSSI, RSRQ, CQI, and/or the like) from controller/processor 280. Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, and/or the like) , and transmitted to base station 110. In some aspects, the UE 120 includes a transceiver. The transceiver may include any combination of antenna (s) 252, modulators and/or demodulators 254, MIMO detector 256, receive processor 258, transmit processor 264, and/or TX MIMO processor 266. The transceiver may be used by a processor (e.g., controller/processor 280) and memory 282 to perform aspects of any of the methods described herein, for example, as described with reference to Figs. 5-6.

At base station 110, the uplink signals from UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, 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 120. Receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to controller/processor 240. Base station 110 may include communication unit 244 and communicate to network controller 130 via communication unit 244. Base station 110 may include a scheduler 246 to schedule UEs 120 for downlink and/or uplink communications. In some aspects, the base station 110 includes a transceiver. The transceiver may include any combination of antenna (s) 234, modulators and/or demodulators 232, MIMO detector 236, receive processor 238, transmit processor 220, and/or TX MIMO processor 230. The transceiver may be used by a processor (e.g., controller/processor 240) and memory 242 to perform aspects of any of the methods described herein, for example, as described with reference to Figs. 5-6.

Controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform one or more techniques associated with reusing a transmit-receive beam pair after a beam failure, as described in more detail elsewhere herein. For example, controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component (s) of Fig. 2 may perform or direct operations of, for example, process 600 of Fig. 6, and/or other processes as described herein.

Memories

242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and/or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code, program code, and/or the like) for wireless communication. For example, the one or more instructions, when executed (e.g., directly, or after compiling, converting, interpreting, and/or the like) by one or more processors of the base station 110 and/or the UE 120, may cause the one or more processors, the UE 120, and/or the base station 110 to perform or direct operations of, for example, process 600 of Fig. 6, and/or other processes as described herein. In some aspects, executing instructions may include running the instructions, converting the instructions, compiling the instructions, interpreting the instructions, and/or the like.

In some aspects, a UE (e.g., UE 120) may include means for detecting a beam failure of a transmit-receive (Tx-Rx) beam pair used by the UE to communicate with a base station, means for transmitting a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time, and/or the like. In some aspects, such means may include one or more components of UE 120 described in connection with Fig. 2, such as controller/processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, and/or the like.

While blocks in Fig. 2 are illustrated as distinct components, the functions described above with respect to the blocks may be implemented in a single hardware, software, or combination component or in various combinations of components. For example, the functions described with respect to the transmit processor 264, the receive processor 258, and/or the TX MIMO processor 266 may be performed by or under the control of controller/processor 280.

As indicated above, Fig. 2 is provided as an example. Other examples may differ from what is described with regard to Fig. 2.

Fig. 3 is a diagram illustrating an example 300 of a four-step random access procedure, in accordance with various aspects of the present disclosure. As shown in Fig. 3, a base station 110 and a UE 120 may communicate with one another to perform the four-step random access procedure.

As shown by reference number 305, the base station 110 may transmit, and the UE 120 may receive, one or more synchronization signal blocks (SSBs) and random access configuration information. In some aspects, the random access configuration information may be transmitted in and/or indicated by system information (e.g., in one or more system information blocks (SIBs) and/or the like) and/or an SSB, such as for contention-based random access. Additionally, or alternatively, the random access configuration information may be transmitted in an RRC message and/or a physical downlink control channel (PDCCH) order message that triggers a random access channel (RACH) procedure, such as for contention-free random access. The random access configuration information may include one or more parameters to be used in the random access procedure, such as one or more parameters for transmitting a random access message (RAM) , one or more parameters for receiving a random access response (RAR) , and/or the like.

As shown by reference number 310, the UE 120 may transmit a RAM, which may include a preamble (sometimes referred to as a random access preamble, a physical random access channel (PRACH) preamble, a RAM preamble, and/or the like) . The message that includes the preamble may be referred to as a message 1, msg1, MSG1, a first message, an initial message, and/or the like in a four-step random access procedure. The RAM may include a random access preamble identifier.

As shown by reference number 315, the base station 110 may transmit an RAR as a reply to the preamble. The message that includes the RAR may be referred to as message 2, msg2, MSG2, or a second message in a four-step random access procedure. In some aspects, the RAR may indicate the detected random access preamble identifier (e.g., received from the UE 120 in msg1) . Additionally, or alternatively, the RAR may indicate a resource allocation to be used by the UE 120 to transmit message 3 (msg3) .

In some aspects, as part of the second step of the four-step random access procedure, the base station 110 may transmit a PDCCH communication for the RAR. The PDCCH communication may schedule a PDSCH communication that includes the RAR. For example, the PDCCH communication may indicate a resource allocation for the PDSCH communication. Also, as part of the second step of the four-step random access procedure, the base station 110 may transmit the PDSCH communication for the RAR, as scheduled by the PDCCH communication. The RAR may be included in a MAC PDU of the PDSCH communication.

As shown by reference number 320, the UE 120 may transmit an RRC connection request message. The RRC connection request message may be referred to as message 3, msg3, MSG3, or a third message of a four-step random access procedure. In some aspects, the RRC connection request may include a UE identifier, UCI, a PUSCH communication (e.g., an RRC connection request) , and/or the like.

As shown by reference number 325, the base station 110 may transmit an RRC connection setup message. The RRC connection setup message may be referred to as message 4, msg4, MSG4, or a fourth message of a four-step random access procedure. In some aspects, the RRC connection setup message may include the detected UE identifier, a timing advance value, contention resolution information, and/or the like. As shown by reference number 330, if the UE 120 successfully receives the RRC connection setup message, the UE 120 may transmit a HARQ ACK.

As indicated above, Fig. 3 is provided as an example. Other examples may differ from what is described with regard to Fig. 3.

Fig. 4 is a diagram illustrating an example 400 of a two-step random access procedure, in accordance with various aspects of the present disclosure. As shown in Fig. 4, a base station 110 and a UE 120 may communicate with one another to perform the two-step random access procedure.

As shown by reference number 405, the base station 110 may transmit, and the UE 120 may receive, one or more SSBs and random access configuration information. In some aspects, the random access configuration information may be transmitted in and/or indicated by system information (e.g., in one or more SIBs and/or the like) and/or an SSB, such as for contention-based random access. Additionally, or alternatively, the random access configuration information may be transmitted in a RRC message and/or a PDCCH order message that triggers a RACH procedure, such as for contention-free random access. The random access configuration information may include one or more parameters to be used in the two-step random access procedure, such as one or more parameters for transmitting a RAM, receiving a RAR to the RAM, and/or the like.

As shown by reference number 410, the UE 120 may transmit, and the base station 110 may receive, a RAM preamble. As shown by reference number 415, the UE 120 may transmit, and the base station 110 may receive, a RAM payload. As shown, the UE 120 may transmit the RAM preamble and the RAM payload to the base station 110 as part of an initial (or first) step of the two-step random access procedure. In some aspects, the RAM may be referred to as message A, msgA, a first message, an initial message, and/or the like in a two-step random access procedure. Furthermore, in some aspects, the RAM preamble may be referred to as a message A preamble, a msgA preamble, a preamble, a PRACH preamble, and/or the like, and the RAM payload may be referred to as a message A payload, a msgA payload, a payload, and/or the like. In some aspects, the RAM may include some or all of the contents of message 1 (msg1) and message 3 (msg3) of a four-step random access procedure, which is described in more detail below. For example, the RAM preamble may include some or all contents of message 1 (e.g., a PRACH preamble) , and the RAM payload may include some or all contents of message 3 (e.g., a UE identifier, uplink control information (UCI) , a physical uplink shared channel (PUSCH) transmission, and/or the like) .

As shown by reference number 420, the base station 110 may receive the RAM preamble transmitted by the UE 120. If the base station 110 successfully receives and decodes the RAM preamble, the base station 110 may then receive and decode the RAM payload.

As shown by reference number 425, the base station 110 may transmit an RAR (sometimes referred to as an RAR message) . As shown, the base station 110 may transmit the RAR message as part of a second step of the two-step random access procedure. In some aspects, the RAR message may be referred to as message B, msgB, or a second message in a two-step random access procedure. The RAR message may include some or all of the contents of message 2 (msg2) and message 4 (msg4) of a four-step random access procedure. For example, the RAR message may include the detected PRACH preamble identifier, the detected UE identifier, a timing advance value, contention resolution information, and/or the like.

As shown by reference number 430, as part of the second step of the two-step random access procedure, the base station 110 may transmit a PDCCH communication for the RAR. The PDCCH communication may schedule a physical downlink shared channel (PDSCH) communication that includes the RAR. For example, the PDCCH communication may indicate a resource allocation (e.g., in downlink control information (DCI) ) for the PDSCH communication.

As shown by reference number 435, as part of the second step of the two-step random access procedure, the base station 110 may transmit the PDSCH communication for the RAR, as scheduled by the PDCCH communication. The RAR may be included in a medium access control (MAC) protocol data unit (PDU) of the PDSCH communication. As shown by reference number 440, if the UE 120 successfully receives the RAR, the UE 120 may transmit a hybrid automatic repeat request (HARQ) acknowledgement (ACK) .

As indicated above, Fig. 4 is provided as an example. Other examples may differ from what is described with regard to Fig. 4.

A UE may communicate with a base station using a Tx-Rx beam. In some cases, a beam failure may occur which may prevent the UE from using the Tx-Rx beam to communicate with the base station. The beam failure may be detected and reported from one protocol stack layer of the UE to another protocol stack layer of the UE. For example, the beam failure may be reported to a media access control (MAC) layer of the UE. The UE may initiate a default NR beam recovery procedure immediately or shortly after the beam failure is detected. During the default NR beam recovery procedure, the UE may measure new candidate Tx-Rx beam pairs. The UE may select a new Tx-Rx beam pair from the new candidate Tx-Rx beam pairs. The UE may initiate a RACH procedure with the base station using the new Tx-Rx beam pair. The UE may initiate the RACH procedure by transmitting a RACH message (e.g., msg1 or msgA) to the base station using the new Tx-Rx beam pair. If the base station does not respond to the RACH message transmitted by the UE, the UE may retransmit the RACH message using the new Tx-Rx beam pair and with an increased power level. In other words, the UE may initiate a power ramping to increase a signal strength associated with the retransmitted RACH message, which may enable the base station to receive and respond to the UE.

The default NR beam recovery procedure may be well-suited for some types of UEs, such as mobile phones. For mobile phones, beam failure is often due to UE motion and/or rotation, so the default NR beam recovery procedure may generally allow the UE to recover from the beam failure in a short period of time.

However, the default NR beam recovery procedure may consume an inordinate amount of power for other types of UEs, such as mMTC/IoT UEs, which may be static or mostly static. One example of an mMTC/IoT UE may be a sensor in a factory. mMTC/IoT UEs may be sensitive to power consumption. The default NR beam recovery procedure, which may involve searching for new candidate Tx-Rx beam pairs, transmitting RACH messages with an increased periodicity, and/or sequential power ramping, may consume an inordinate amount of power for mMTC/IoT UEs.

For mMTC/IoT UEs, which generally are static, beam failure may not be due to UE motion and/or rotation. Rather, the beam failure may be due to a physical object blocking the Tx-Rx beam pair of the UE. The beam failure may be due to a change to one or more spatial filters associated with the Tx-Rx beam pair. The beam failure may be due to a change to a beam signal strength or a direction of the Tx-Rx beam pair. For example, the change to the beam signal strength or the direction of the Tx-Rx beam pair may occur at the base station. Since an mMTC/IoT UE is generally static and the beam failure is not due to UE motion and/or rotation, the default NR beam recovery procedure may not recover the beam failure in a short period of time, so the increased power consumption associated with the default NR beam recovery procedure may further drain a battery of the mMTC/IoT UE.

In various aspects of techniques and apparatuses described herein, a UE (e.g., an mMTC/IoT UE) may detect a beam failure associated with a Tx-Rx beam pair. The UE may reuse the Tx-Rx beam pair to transmit a RACH message after waiting a predetermined amount of time after the beam failure occurs. In other words, the UE may wait the predetermined amount of time after the beam failure occurs, and then the UE may use the same Tx-Rx beam pair that was previously associated with the beam failure to transmit the RACH message. The UE may be a delay-tolerant UE, so waiting the predetermined amount of time before transmitting the RACH message may be acceptable for the UE. The UE may not search for new candidate Tx-Rx beam pairs, and the UE may not apply sequential power ramping, which may save power at the UE. Since the UE (e.g., the mMTC/IoT UE) may be mostly static, the UE may not search for a new candidate Tx-Rx beam pair, but rather may reuse the same Tx-Rx beam pair at a later time. At the later time, a likelihood of the Tx-Rx beam pair being recovered may be increased (e.g., due to a physical object that is no longer blocking the Tx-Rx beam pair, due to a return to a previous spatial filter associated with the Tx-Rx beam pair, or due to a return to a previous beam signal strength or the direction of the Tx-Rx beam pair) . In other words, at the later time, the beam failure is likely to have been resolved.

Fig. 5 is a diagram illustrating an example 500 associated with reusing a transmit-receive beam pair after a beam failure, in accordance with various aspects of the present disclosure. As shown in Fig. 5, example 500 includes communication between a UE (e.g., UE 120a) and a base station (e.g., base station 110a) . In some aspects, the UE and the base station may be included in a wireless network such as wireless network 100. The UE and the base station may communicate on a wireless sidelink.

In some aspects, the UE may be an mMTC/IoT UE with no or limited mobility. In some aspects, the UE may be a delay-tolerant UE. In other words, a delay of, for example, one second, one minute, ten minutes, and/or the like during a beam recovery procedure may be acceptable for the UE.

As shown by reference number 502, the UE may detect a beam failure of a Tx-Rx beam pair used by the UE to communicate with the base station. The UE may detect the beam failure based at least in part on a physical object blocking the Tx-Rx beam pair. The UE may detect the beam failure based at least in part on a change to one or more spatial filters associated with the Tx-Rx beam pair. The UE may detect the beam failure based at least in part on a change to a beam signal strength or a direction of the Tx-Rx beam pair.

As shown by reference number 504, the UE may transmit a RACH message to the base station using the Tx-Rx beam pair after a predetermined amount of time. In other words, the UE may transmit the RACH message by reusing the Tx-Rx beam pair that was previously associated with the beam failure, or by reusing the Tx-Rx beam pair that was successfully used prior to the beam failure. The UE may transmit the RACH message to the base station as part of a beam recovery procedure performed at the UE. The RACH message may be a msg1 or a msgA transmitted from the UE in accordance with a RACH procedure. The UE may transmit the RACH message using the Tx-Rx beam pair without measuring new candidate Tx-Rx beam pairs, which may save power at the UE.

In some aspects, after detecting the beam failure of the Tx-Rx beam pair, the UE may not immediately transmit the RACH message to the base station using the Tx-Rx beam pair. Rather, the UE may wait until the predetermined amount of time has passed to transmit the RACH message to the base station. By waiting for the predetermined amount of time to pass, a likelihood of the beam failure being naturally resolved may be increased. As a result, the UE may not waste power by not measuring new candidate Tx-Rx beam pairs, and by not performing repeated transmissions of the RACH message to the base station in relatively short time intervals.

In some aspects, the UE may receive a response from the base station after transmitting the RACH message to the base station. For example, the base station may respond to the RACH message received from the UE. In this case, the UE may continue with the beam recovery procedure and transmit other RACH messages (e.g., msg3 or msgB) to the base station using the Tx-Rx beam pair. After completing the RACH procedure, the Tx-Rx beam pair may no longer be subject to the beam failure.

In some aspects, the UE may not receive a response from the base station after transmitting the RACH message to the base station. For example, the base station may not respond to the RACH message received from the UE.

As shown by reference number 506, the UE may retransmit the RACH message to the base station using the Tx-Rx beam pair after a second predetermined amount of time. The predetermined amount of time after which the UE previously transmits the RACH message to the base station may be a first predetermined amount of time. The UE may retransmit the RACH message using the Tx-Rx beam pair after the second predetermined amount of time when no response is received from the base station after transmitting the RACH message. The UE may retransmit the RACH message to the base station as part of the beam recovery procedure performed at the UE.

In some aspects, the second predetermined amount of time may be greater than the first predetermined amount of time. In other words, the UE may wait an increased period of time before retransmitting the RACH message as compared to when the UE waited to transmit the RACH message. In some aspects, the second predetermined amount of time may be less than or equal to the first predetermined amount of time.

In some aspects, the UE may retransmit the RACH message without increasing a power level associated with the RACH message to save power at the UE. In other words, rather than increasing the power level associated with the retransmission of the RACH message to increase a likelihood that the base station receives and responds to the RACH message, the UE may wait the second predetermined amount of time (which may be greater than the first predetermined amount of time) to retransmit the RACH message. By waiting for the second predetermined amount of time, the UE may increase the likelihood that the base station may receive and respond to the RACH message, while not increasing power consumption at the UE.

In some aspects, the UE may transmit the RACH message after the first predetermined amount of time, and the UE may retransmit the RACH message after the second predetermined amount of time based at least in part on a network configuration and/or a UE local configuration. For example, the UE may receive, from the base station, a configuration that indicates the first predetermined amount of time and the second predetermined amount of time. The UE may receive the configuration prior to detection of the beam failure.

In some aspects, the UE may retransmit the RACH message a number of times based at least in part on a network configuration and/or a UE local configuration. For example, the UE may receive, from the base station, a configuration that indicates the number of times the UE is to transmit the RACH message to the base station before initiating a radio link failure recovery procedure with the base station. The configuration may include, for each time the UE may retransmit the RACH message, a predetermined amount of time the UE is to wait before retransmitting the RACH message for that time. The UE may receive the configuration prior to detection of the beam failure.

As an example, the configuration may include, for a first retransmission of the RACH message, a predetermined wait time of five minutes. Also as an example, the configuration may include, for a second retransmission of the RACH message, a predetermined wait time of twenty minutes. As a further example, the configuration may include, for a third retransmission of the RACH message, a predetermined wait time of 60 minutes.

As shown by reference number 506, the UE may transmit a radio link failure recovery message to the base station. The UE may transmit the radio link failure recovery message to the base station when the base station does not respond to the RACH message transmitted by the UE. For example, the UE may transmit the radio link failure recovery message after the UE has retransmitted the RACH message a number of times in accordance with the configuration received from the base station or the UE local configuration.

As an example, a UE located in a factory may experience a beam failure. The UE may currently be using a Tx 2 ^nd and Rx 1 ^st beam pair to communicate with a base station. After experiencing the beam failure, the UE may wait for ten minutes and then transmit a RACH message to the base station using the Tx 2 ^nd and Rx 1 ^st beam pair. The UE may initially not receive a response to the RACH message. The UE may wait for fifty minutes and then retransmit the RACH message to the base station using the Tx 2 ^nd and Rx 1 ^st beam pair. The base station may respond to the retransmission of the RACH message. The UE and the base station may communicate additional RACH messages using the Tx 2 ^nd and Rx 1 ^st beam pair, which may lead to a successful beam recovery.

As indicated above, Fig. 5 is provided as an example. Other examples may differ from what is described with regard to Fig. 5.

Fig. 6 is a diagram illustrating an example process 600 performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 600 is an example where the UE (e.g., UE 120) performs operations associated with reusing a transmit-receive beam pair after a beam failure.

As shown in Fig. 6, in some aspects, process 600 may include detecting a beam failure of a Tx-Rx beam pair used by the UE to communicate with a base station (block 610) . For example, the UE (e.g., using detection component 708, depicted in Fig. 7) may detect a beam failure of a Tx-Rx beam pair used by the UE to communicate with a base station, as described above.

As further shown in Fig. 6, in some aspects, process 600 may include transmitting a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time (block 620) . For example, the UE (e.g., using transmission component 704, depicted in Fig. 7) may transmit a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time, as described above.

Process 600 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, the predetermined amount of time is a first predetermined amount of time, and process 600 includes retransmitting the random access channel message to the base station using the Tx-Rx beam pair after a second predetermined amount of time, when no response is received from the base station after transmitting the random access channel message, wherein the second predetermined amount of time is greater than the first predetermined amount of time.

In a second aspect, alone or in combination with the first aspect, retransmitting the random access channel message comprises retransmitting the random access channel message without increasing a power level associated with the random access channel message.

In a third aspect, alone or in combination with one or more of the first and second aspects, process 600 includes receiving, from the base station, a configuration that indicates the predetermined amount of time.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, process 600 includes receiving, from the base station, a configuration that indicates a number of times the UE is to transmit the random access channel message to the base station before initiating a radio link failure recovery procedure with the base station.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process 600 includes initiating a radio link failure recovery procedure with the base station when no response is received from the base station after transmitting the random access channel message.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, detecting the beam failure comprises detecting the beam failure based at least in part on a physical object blocking the Tx-Rx beam pair.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, detecting the beam failure comprises detecting the beam failure based at least in part on a change to one or more spatial filters associated with the Tx-Rx beam pair.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, detecting the beam failure comprises detecting the beam failure based at least in part on a change to a beam signal strength or a direction of the Tx-Rx beam pair.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, transmitting the random access channel message comprises transmitting the random access channel message using the Tx-Rx beam pair without measuring new candidate Tx-Rx beam pairs.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, transmitting the random access channel message comprises transmitting the random access channel message using the Tx-Rx beam pair during a beam recovery procedure performed at the UE.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the UE is a delay-tolerant UE.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, the UE is a device with no or limited mobility.

In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, the UE is a Massive Machine-type Communication device.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, the UE is an Internet of Things device.

Although Fig. 6 shows example blocks of process 600, in some aspects, process 600 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Fig. 6. Additionally, or alternatively, two or more of the blocks of process 600 may be performed in parallel.

Fig. 7 is a block diagram of an example apparatus 700 for wireless communication. The apparatus 700 may be a UE, or a UE may include the apparatus 700. In some aspects, the apparatus 700 includes a reception component 702 and a transmission component 704, which may be in communication with one another (for example, via one or more buses and/or one or more other components) . As shown, the apparatus 700 may communicate with another apparatus 706 (such as a UE, a base station, or another wireless communication device) using the reception component 702 and the transmission component 704. As further shown, the apparatus 700 may include one or more of a detection component 708, or an initiation component 710, among other examples.

In some aspects, the apparatus 700 may be configured to perform one or more operations described herein in connection with Fig. 5. Additionally or alternatively, the apparatus 700 may be configured to perform one or more processes described herein, such as process 600 of Fig. 6. In some aspects, the apparatus 700 and/or one or more components shown in Fig. 7 may include one or more components of the UE described above in connection with Fig. 2. Additionally, or alternatively, one or more components shown in Fig. 7 may be implemented within one or more components described above in connection with Fig. 2. Additionally or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of the component.

The reception component 702 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 706. The reception component 702 may provide received communications to one or more other components of the apparatus 700. In some aspects, the reception component 702 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, de-mapping, equalization, interference cancellation, or decoding, among other examples) , and may provide the processed signals to the one or more other components of the apparatus 706. In some aspects, the reception component 702 may include one or more antennas, a demodulator, a MIMO detector, a receive processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with Fig. 2.

The transmission component 704 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 706. In some aspects, one or more other components of the apparatus 706 may generate communications and may provide the generated communications to the transmission component 704 for transmission to the apparatus 706. In some aspects, the transmission component 704 may perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples) , and may transmit the processed signals to the apparatus 706. In some aspects, the transmission component 704 may include one or more antennas, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with Fig. 2. In some aspects, the transmission component 704 may be collocated with the reception component 702 in a transceiver.

In some aspects, the detection component 708 may detect a beam failure of a Tx-Rx beam pair used by the UE to communicate with a base station. In some aspects, the detection component 708 may detect the beam failure based at least in part on a physical object blocking the Tx-Rx beam pair. In some aspects, the detection component 708 may detect the beam failure based at least in part on a change to one or more spatial filters associated with the Tx-Rx beam pair. In some aspects, the detection component 708 may detect the beam failure based at least in part on a change to a beam signal strength or a direction of the Tx-Rx beam pair.

In some aspects, the detection component 708 may include one or more antennas, a demodulator, a MIMO detector, a receive processor, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with Fig. 2.

In some aspects, the transmission component 704 may transmit a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time. In some aspects, the predetermined amount of time is a first predetermined amount of time, and the transmission component 704 may retransmit the random access channel message to the base station using the Tx-Rx beam pair after a second predetermined amount of time, when no response is received from the base station after transmitting the random access channel message, wherein the second predetermined amount of time is greater than the first predetermined amount of time. In some aspects, the transmission component 704 may retransmit the random access channel message without increasing a power level associated with the random access channel message. In some aspects, the transmission component 704 may transmit the random access channel message using the Tx-Rx beam pair without measuring new candidate Tx-Rx beam pairs. In some aspects, the transmission component 704 may transmit the random access channel message using the Tx-Rx beam pair during a beam recovery procedure performed at the UE.

In some aspects, the reception component 702 may receive, from the base station, a configuration that indicates the predetermined amount of time. In some aspects, the reception component 702 may receive, from the base station, a configuration that indicates a number of times the UE is to transmit the random access channel message to the base station before initiating a radio link failure recovery procedure with the base station.

In some aspects, the initiation component 710 may initiate a radio link failure recovery procedure with the base station when no response is received from the base station after transmitting the random access channel message.

In some aspects, the initiation component 710 may include one or more antennas, a demodulator, a MIMO detector, a receive processor, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with Fig. 2.

The number and arrangement of components shown in Fig. 7 are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in Fig. 7. Furthermore, two or more components shown in Fig. 7 may be implemented within a single component, or a single component shown in Fig. 7 may be implemented as multiple, distributed components. Additionally or alternatively, a set of (one or more) components shown in Fig. 7 may perform one or more functions described as being performed by another set of components shown in Fig. 7.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.

As used herein, the term “component” is intended to be broadly construed as hardware, firmware, and/or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, and/or a combination of hardware and software. It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware, firmware, and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to specific software code-it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein.

As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and/or the like.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. 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, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c) .

No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items and may be used interchangeably with “one or more. ” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more. ” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, and/or the like) , and may be used interchangeably with “one or more. ” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has, ” “have, ” “having, ” and/or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or, ” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of” ) .

Claims

A method of wireless communication performed by a user equipment (UE) , comprising:

detecting a beam failure of a transmit-receive (Tx-Rx) beam pair used by the UE to communicate with a base station; and

transmitting a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time.
The method of claim 1, wherein the predetermined amount of time is a first predetermined amount of time, and further comprising:

retransmitting the random access channel message to the base station using the Tx-Rx beam pair after a second predetermined amount of time, when no response is received from the base station after transmitting the random access channel message, wherein the second predetermined amount of time is greater than the first predetermined amount of time.
The method of claim 2, wherein retransmitting the random access channel message comprises retransmitting the random access channel message without increasing a power level associated with the random access channel message.
The method of claim 1, further comprising:

receiving, from the base station, a configuration that indicates the predetermined amount of time.
The method of claim 1, further comprising:

receiving, from the base station, a configuration that indicates a number of times the UE is to transmit the random access channel message to the base station before initiating a radio link failure recovery procedure with the base station.
The method of claim 1, further comprising:

initiating a radio link failure recovery procedure with the base station when no response is received from the base station after transmitting the random access channel message.
The method of claim 1, wherein detecting the beam failure comprises detecting the beam failure based at least in part on a physical object blocking the Tx-Rx beam pair.
The method of claim 1, wherein detecting the beam failure comprises detecting the beam failure based at least in part on a change to one or more spatial filters associated with the Tx-Rx beam pair.
The method of claim 1, wherein detecting the beam failure comprises detecting the beam failure based at least in part on a change to a beam signal strength or a direction of the Tx-Rx beam pair.
The method of claim 1, wherein transmitting the random access channel message comprises transmitting the random access channel message using the Tx-Rx beam pair without measuring new candidate Tx-Rx beam pairs.
The method of claim 1, wherein transmitting the random access channel message comprises transmitting the random access channel message using the Tx-Rx beam pair during a beam recovery procedure performed at the UE.
The method of claim 1, wherein the UE is a delay-tolerant UE.
The method of claim 1, wherein the UE is a device with no or limited mobility.
The method of claim 1, wherein the UE is a Massive Machine-type Communication device.
The method of claim 1, wherein the UE is an Internet of Things device.
A user equipment (UE) for wireless communication, comprising:

a memory; and

one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:

detect a beam failure of a transmit-receive (Tx-Rx) beam pair used by the UE to communicate with a base station; and

transmit a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time.
The UE of claim 16, wherein the predetermined amount of time is a first predetermined amount of time, and wherein the one or more processors are further configured to:

retransmit the random access channel message to the base station using the Tx-Rx beam pair after a second predetermined amount of time, when no response is received from the base station after transmitting the random access channel message, wherein the second predetermined amount of time is greater than the first predetermined amount of time.
The UE of claim 17, wherein the one or more processors, when retransmitting the random access channel message, are configured to retransmit the random access channel message without increasing a power level associated with the random access channel message.
The UE of claim 16, wherein the one or more processors are further configured to:

receive, from the base station, a configuration that indicates the predetermined amount of time.
The UE of claim 16, wherein the one or more processors are further configured to:

receive, from the base station, a configuration that indicates a number of times the UE is to transmit the random access channel message to the base station before initiating a radio link failure recovery procedure with the base station.
The UE of claim 16, wherein the one or more processors are further configured to:

initiate a radio link failure recovery procedure with the base station when no response is received from the base station after transmitting the random access channel message.
The UE of claim 16, wherein the one or more processors, when detecting the beam failure, are configured to detect the beam failure based at least in part on a physical object blocking the Tx-Rx beam pair.
The UE of claim 16, wherein the one or more processors, when detecting the beam failure, are configured to detect the beam failure based at least in part on a change to one or more spatial filters associated with the Tx-Rx beam pair.
The UE of claim 16, wherein the one or more processors, when detecting the beam failure, are configured to detect the beam failure based at least in part on a change to a beam signal strength or a direction of the Tx-Rx beam pair.
The UE of claim 16, wherein the one or more processors, when transmitting the random access channel message, are configured to transmit the random access channel message using the Tx-Rx beam pair without measuring new candidate Tx-Rx beam pairs.
The UE of claim 16, wherein the one or more processors, when transmitting the random access channel message, are configured to transmit the random access channel message using the Tx-Rx beam pair during a beam recovery procedure performed at the UE.
The UE of claim 16, wherein the UE is a delay-tolerant UE.
The UE of claim 16, wherein the UE is a device with no or limited mobility.
The UE of claim 16, wherein the UE is a Massive Machine-type Communication device.
The UE of claim 16, wherein the UE is an Internet of Things device.
A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising:

one or more instructions that, when executed by one or more processors of a user equipment (UE) , cause the UE to:

detect a beam failure of a transmit-receive (Tx-Rx) beam pair used by the UE to communicate with a base station; and

transmit a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time.
The non-transitory computer-readable medium of claim 31, wherein the predetermined amount of time is a first predetermined amount of time, and wherein the one or more instructions further cause the UE to:

retransmit the random access channel message to the base station using the Tx-Rx beam pair after a second predetermined amount of time, when no response is received from the base station after transmitting the random access channel message, wherein the second predetermined amount of time is greater than the first predetermined amount of time.
The non-transitory computer-readable medium of claim 32, wherein the one or more instructions, that cause the UE to retransmit the random access channel message, cause the UE to retransmit the random access channel message without increasing a power level associated with the random access channel message.
The non-transitory computer-readable medium of claim 31, wherein the one or more instructions further cause the UE to:

receive, from the base station, a configuration that indicates the predetermined amount of time.
The non-transitory computer-readable medium of claim 31, wherein the one or more instructions further cause the UE to:

receive, from the base station, a configuration that indicates a number of times the UE is to transmit the random access channel message to the base station before initiating a radio link failure recovery procedure with the base station.
The non-transitory computer-readable medium of claim 31, wherein the one or more instructions further cause the UE to:

initiate a radio link failure recovery procedure with the base station when no response is received from the base station after transmitting the random access channel message.
The non-transitory computer-readable medium of claim 31, wherein the one or more instructions, that cause the UE to detect the beam failure, cause the UE to detect the beam failure based at least in part on a physical object blocking the Tx-Rx beam pair.
The non-transitory computer-readable medium of claim 31, wherein the one or more instructions, that cause the UE to detect the beam failure, cause the UE to detect the beam failure based at least in part on a change to one or more spatial filters associated with the Tx-Rx beam pair.
The non-transitory computer-readable medium of claim 31, wherein the one or more instructions, that cause the UE to detect the beam failure, cause the UE to detect the beam failure based at least in part on a change to a beam signal strength or a direction of the Tx-Rx beam pair.
The non-transitory computer-readable medium of claim 31, wherein the one or more instructions, that cause the UE to transmit the random access channel message, cause the UE to transmit the random access channel message using the Tx-Rx beam pair without measuring new candidate Tx-Rx beam pairs.
The non-transitory computer-readable medium of claim 31, wherein the one or more instructions, that cause the UE to transmit the random access channel message, cause the UE to transmit the random access channel message using the Tx-Rx beam pair during a beam recovery procedure performed at the UE.
The non-transitory computer-readable medium of claim 31, wherein the UE is a delay-tolerant UE.
The non-transitory computer-readable medium of claim 31, wherein the UE is a device with no or limited mobility.
The non-transitory computer-readable medium of claim 31, wherein the UE is a Massive Machine-type Communication device.
The non-transitory computer-readable medium of claim 31, wherein the UE is an Internet of Things device.
An apparatus for wireless communication, comprising:

means for detecting a beam failure of a transmit-receive (Tx-Rx) beam pair used by the apparatus to communicate with a base station; and

means for transmitting a random access channel message to the base station using the Tx-Rx beam pair after a predetermined amount of time.
The apparatus of claim 46, wherein the predetermined amount of time is a first predetermined amount of time, and further comprising:

means for retransmitting the random access channel message to the base station using the Tx-Rx beam pair after a second predetermined amount of time, when no response is received from the base station after transmitting the random access channel message, wherein the second predetermined amount of time is greater than the first predetermined amount of time.
The apparatus of claim 47, wherein the means for retransmitting the random access channel message comprises means for retransmitting the random access channel message without increasing a power level associated with the random access channel message.
The apparatus of claim 46, further comprising:

means for receiving, from the base station, a configuration that indicates the predetermined amount of time.
The apparatus of claim 46, further comprising:

means for receiving, from the base station, a configuration that indicates a number of times the apparatus is to transmit the random access channel message to the base station before initiating a radio link failure recovery procedure with the base station.
The apparatus of claim 46, further comprising:

means for initiating a radio link failure recovery procedure with the base station when no response is received from the base station after transmitting the random access channel message.
The apparatus of claim 46, wherein the means for detecting the beam failure comprises means for detecting the beam failure based at least in part on a physical object blocking the Tx-Rx beam pair.
The apparatus of claim 46, wherein the means for detecting the beam failure comprises means for detecting the beam failure based at least in part on a change to one or more spatial filters associated with the Tx-Rx beam pair.
The apparatus of claim 46, wherein the means for detecting the beam failure comprises means for detecting the beam failure based at least in part on a change to a beam signal strength or a direction of the Tx-Rx beam pair.
The apparatus of claim 46, wherein the means for transmitting the random access channel message comprises means for transmitting the random access channel message using the Tx-Rx beam pair without measuring new candidate Tx-Rx beam pairs.
The apparatus of claim 46, wherein the means for transmitting the random access channel message comprises means for transmitting the random access channel message using the Tx-Rx beam pair during a beam recovery procedure performed at the UE.
The apparatus of claim 46, wherein the apparatus is a delay-tolerant apparatus.
The apparatus of claim 46, wherein the apparatus is a device with no or limited mobility.
The apparatus of claim 46, wherein the apparatus is a Massive Machine-type Communication device.
The apparatus of claim 46, wherein the apparatus is an Internet of Things device.
A method, device, apparatus, computer program product, non-transitory computer-readable medium, user equipment, base station, node, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the accompanying drawings and specification.