Physical random access channel repetition and receive beam scanning and associated beam refinement

Abstract

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for beam refinement via physical random access channel (PRACH) repetitions. A method for wireless communications by a network entity includes: determining resources for monitoring PRACH transmissions sent from a user equipment (UE) as part of a random access channel (RACH) procedure; performing receive beam scanning when receiving PRACH repetitions sent using the determined resources; using the results of the receive beam scanning to refine one or more beams and selecting a refined beam from the refined one or more beams; and using the selected refined beam to at least one of receive a subsequent message from the UE as part of the RACH procedure or send a subsequent message to the UE as part of the RACH procedure.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Application No. 17 / 179,139, filed on February 18, 2021, which claims the benefit of and priority to U.S. Provisional Application No. 62 / 980,095, filed on February 21, 2020, which are hereby assigned to the assignee of the present application and are hereby expressly incorporated herein by reference in their entireties as if fully set forth below and for all applicable purposes. Technical Field

[0003] Aspects of the present disclosure relate to wireless communications and, more particularly, to techniques for beam refinement via physical random access channel (PRACH) repetitions. Background Art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcast, etc. These wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, Advanced LTE (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 (SCFDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name just a few.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at municipal, national, regional, and even global levels. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is an enhancement set to the LTE mobile standard released by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0006] However, as the demand for mobile broadband access continues to increase, further improvements in NR and LTE technologies are needed. These improvements should also apply to other multiple access technologies and the telecommunication standards that adopt them. Summary of the invention

[0007] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. After considering this discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide advantages including improved communication between access points and stations in a wireless network.

[0008] Certain aspects of the present disclosure provide a method for wireless communication by a network entity. The method generally includes determining resources used to monitor a physical random access channel (PRACH) transmission sent from a user equipment (UE) as part of a random access channel (RACH) procedure. The method generally includes performing receive beam scanning when receiving PRACH repetitions sent using the determined resources. The method generally includes using the results of the beam scanning to refine one or more beams and selecting a refined beam from the refined one or more beams. The method generally includes using the selected refined beam to at least one of receive a subsequent message from the UE as part of the RACH procedure or send a subsequent message to the UE as part of the RACH procedure.

[0009] Certain aspects provide a method of wireless communication performed by a UE. The method generally includes determining RACH resources associated with one or more synchronization signal block (SSB) beams for sending PRACH transmissions with repetitions. The method generally includes sending the PRACH repetitions using resources corresponding to the determined RACH opportunities if one or more conditions are met.

[0010] Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus includes at least one processor and a memory coupled to the at least one processor. The memory generally includes code that can be executed by the at least one processor to cause the apparatus to perform the following operations: determine resources used to monitor PRACH transmissions sent from a UE as part of a RACH process. The memory generally includes code that can be executed by the at least one processor to cause the apparatus to perform receive beam scanning when receiving PRACH repetitions sent using the determined resources. The memory generally includes code that can be executed by the at least one processor to cause the apparatus to refine one or more beams using the results of the beam scanning and select a refined beam from the refined one or more beams. The memory generally includes code that can be executed by the at least one processor to cause the apparatus to use the selected refined beam to at least one of receive a subsequent message from the UE as part of a RACH process or send a subsequent message to the UE as part of a RACH process.

[0011] Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus includes at least one processor and a memory coupled to the at least one processor. The memory generally includes code that can be executed by the at least one processor to cause the apparatus to determine RACH resources associated with one or more SSB beams for sending PRACH transmissions with repetitions. The memory generally includes code that can be executed by the at least one processor to cause the apparatus to: send PRACH repetitions using resources corresponding to the determined RACH opportunities if one or more conditions are met.

[0012] Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes components for determining resources used to monitor PRACH transmissions sent from a UE as part of a RACH procedure. The apparatus generally includes components for performing receive beam scanning when receiving PRACH repetitions sent using the determined resources. The apparatus generally includes components for using the results of the beam scanning to refine one or more beams and select a refined beam from the refined one or more beams. The apparatus generally includes using the selected refined beam to at least one of receive a subsequent message from the UE as part of the RACH procedure or send a subsequent message to the UE as part of the RACH procedure.

[0013] Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes means for determining RACH resources associated with one or more SSB beams for sending PRACH transmissions with repetitions. The apparatus generally includes means for sending PRACH repetitions using resources corresponding to the determined RACH opportunities if one or more conditions are met.

[0014] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication having computer executable code stored thereon. The computer-readable medium generally includes code for determining resources used to monitor PRACH transmissions sent from a UE as part of a RACH process. The computer-readable medium generally includes code for performing receive beam scanning when receiving PRACH repetitions sent using the determined resources. The computer-readable medium generally includes code for using the results of the beam scanning to refine one or more beams and selecting a refined beam from the refined one or more beams. The computer-readable medium generally includes using the selected refined beam to at least one of receive a subsequent message from the UE as part of a RACH process or send a subsequent message to the UE as part of a RACH process.

[0015] Certain aspects provide a computer-readable medium for wireless communications having computer-executable code stored thereon. The computer-readable medium generally includes code for determining RACH resources associated with one or more SSB beams for transmitting PRACH transmissions with repetitions. The computer-readable medium generally includes code for transmitting PRACH repetitions using resources corresponding to the determined RACH opportunities if one or more conditions are met.

[0016] To achieve the aforementioned and related purposes, one or more aspects include features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are only indicative of some of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order that the above-mentioned features of the present disclosure may be understood in detail, a more particular description of the content briefly summarized above may be made with reference to various aspects, wherein some aspects are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate certain aspects of the present disclosure, and the description may allow for other equally effective aspects.

[0018] Figure 1 is a block diagram conceptually illustrating an example wireless communication network in accordance with certain aspects of the present disclosure.

[0019] Figure 2 is a block diagram illustrating an example logical architecture of a distributed radio access network (RAN) in accordance with certain aspects of the present disclosure.

[0020] Figure 3 is a diagram illustrating an exemplary physical architecture of a distributed RAN in accordance with certain aspects of the present disclosure.

[0021] Figure 4 is a block diagram conceptually illustrating designs of exemplary base stations (BSs) and user equipment (UEs) in accordance with certain aspects of the present disclosure.

[0022] Figure 5 is a diagram illustrating an example for implementing a communication protocol stack in accordance with certain aspects of the present disclosure.

[0023] Figure 6 FIG. 1 illustrates an exemplary frame format for certain wireless communication systems (e.g., New Radio (NR)) according to certain aspects of the present disclosure.

[0024] Figure 7 Illustrated how different synchronization signal blocks (SSBs) may be transmitted using different beams in accordance with certain aspects of the present disclosure.

[0025] Figure 8An exemplary transmission resource mapping according to aspects of the present disclosure is illustrated.

[0026] Fig. 9 An exemplary quasi-co-localized (QCL) relationship is illustrated.

[0027] Fig.10 is a timing diagram illustrating an example four-step RACH procedure in accordance with certain aspects of the present disclosure.

[0028] Fig.11 is a flow chart illustrating example operations for wireless communications by a UE in accordance with certain aspects of the present disclosure.

[0029] Fig.12 is a flow diagram illustrating example operations for wireless communications by a network entity in accordance with certain aspects of the present disclosure.

[0030] Fig.13 is a call flow diagram illustrating example operations for beam refinement according to some aspects of the present disclosure.

[0031] Fig.14 A communication device according to aspects of the present disclosure is illustrated that may include various components configured to perform operations of the techniques disclosed herein.

[0032] Fig.15 A communication device according to aspects of the present disclosure is illustrated that may include various components configured to perform operations of the techniques disclosed herein.

[0033] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation. DETAILED DESCRIPTION

[0034] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for beam refinement via physical random access channel (PRACH) repetitions.

[0035] The following description provides an example of beam refinement repeated via PRACH in a communication system. The functions and arrangements of the elements discussed may be changed. Various examples may appropriately omit, replace or add various processes or components. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted or combined. In addition, the features described with respect to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the present disclosure is intended to cover such devices or methods practiced using other structures, functionalities, or structures and functionalities as a supplement to the various aspects of the present disclosure set forth herein or in addition. It should be understood that any aspect of the present disclosure disclosed herein may be implemented by one or more elements of the claims. The word "exemplary" is used herein to mean "used as an example, instance, or illustration". Any aspect described herein as "exemplary" need not be interpreted as being preferred or advantageous over other aspects.

[0036] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. RAT may also be referred to as radio technology, air interface, etc. Frequency may also be referred to as 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.

[0037] New Radio NR access (e.g., 5G NR technology) can support various wireless communication services, such as enhanced mobile broadband (eMMB) targeting wide bandwidth (e.g., 80 MHz or higher), millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or higher), massive machine type communication MTC (mMTC) targeting non-backward compatible MTC technology, and / or mission critical targeting ultra-reliable low latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet corresponding quality of service (QoS) requirements. In addition, these services can coexist in the same subframe.

[0038] NR supports beamforming and the beam direction can be dynamically configured. MIMO transmission with precoding can also be supported. MIMO configuration in DL can support up to 8 transmit antennas (multi-layer DL transmission with up to 8 streams and up to 2 streams per UE). Multi-layer transmission with up to 2 streams per UE can be supported. Aggregation of multiple cells can be supported using up to 8 serving cells.

[0039] Figure 1An exemplary wireless communication network 100 is illustrated in which various aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be an NR system (e.g., a 5G NR network). Figure 1 As shown, the wireless communication network 100 may communicate with a core network 132. The core network 132 may communicate with one or more base stations (BSs) 110a-z (each BS is also individually referred to herein as BS 110 or collectively referred to herein as BS 110) and / or user equipments (UEs) 120a-y (each UE is also individually referred to herein as UE 120 or collectively referred to herein as UE 120) in the wireless communication network 100 via one or more interfaces.

[0040] According to certain aspects, BS 110 and UE 120 may be configured for beam refinement via PRACH repetition. Figure 1 As shown, according to aspects of the present disclosure, the BS 110a includes a beam manager 112 that performs beam refinement based on PRACH repetitions. According to aspects of the present disclosure, the UE 120a includes a PRACH repetition manager 122 that transmits PRACH repetitions corresponding to determined RACH opportunities.

[0041] BS 110 may provide communication coverage for a particular geographic area, sometimes referred to as a "cell," which may be stationary or may move depending on the location of mobile BS 110. In some examples, BS 110 may be interconnected to each other and / or to one or more other BSs or network nodes (not shown) in 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. Figure 1 In the illustrated example, 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.

[0042] The BS 110 communicates with the UE 120 in 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 stationary or mobile. The wireless communication network 100 may also include a relay station (e.g., relay station 110r), also referred to as a relay, etc., which receives transmissions of data and / or other information from an upstream station (e.g., BS 110a or UE 120r) and sends transmissions of data and / or other information to a downstream station (e.g., UE 120 or BS 110), or relays transmissions of other UEs 120 to facilitate communication between devices.

[0043] The network controller 130 may be coupled to the set of BSs 110 and provide coordination and control for these BSs (e.g., via a backhaul). In various aspects, the network controller 130 may communicate 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, unified data management, application functions, network exposure functions, network repository functions, network slice selection functions, etc.

[0044] Figure 2 An exemplary logical architecture of a distributed radio access network (RAN) 200 is shown, which may be Figure 1 200. The 5G access node 206 may include an access node controller (ANC) 202. The ANC 202 may be a central unit (CU) of the distributed RAN 200. The backhaul interface to the next generation core network (NG-CN) 204 may terminate at the ANC 202. The backhaul interface to the adjacent next generation access node (NGAN) 210 may terminate at the ANC 202. The ANC 202 may include one or more transmit receive points (TRPs) 208 (e.g., cells, BSs, gNBs, etc.).

[0045] The TRP 208 may be a distributed unit (DU). The TRP 208 may be connected to a single ANC (e.g., ANC 202) or more than one ANC (not shown). For example, for RAN sharing, Radio as a Service (RaaS), and service-specific ANC deployments, the TRP 208 may be connected to more than one ANC. The TRPs 208 may each include one or more antenna ports. The TRPs 208 may be configured to provide services to the UE individually (e.g., dynamically selected) or jointly (e.g., joint transmission).

[0046] The logical architecture of the distributed RAN 200 can support various backhaul and fronthaul solutions. Such support can occur across and across different deployment types. For example, the logical architecture can be based on transport network capabilities (e.g., bandwidth, latency, and / or jitter).

[0047] The logical architecture of the distributed RAN 200 may share features and / or components with LTE. For example, the next generation access node (NG-AN) 210 may support dual connectivity with NR and may share a common fronthaul of LTE and NR.

[0048] The logical architecture of the distributed RAN 200 may enable collaboration between TRPs 208, for example, within a TRP and / or across TRPs via the ANC 202. An inter-TRP interface may not be used.

[0049] Logical functions may be dynamically distributed in the logical architecture of the distributed RAN 200. Figure 5 Described in more detail, the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, the medium access control (MAC) layer, and the physical (PHY) layer can be adaptively placed at the DU (e.g., TRP 208) or the CU (e.g., ANC 202).

[0050] Figure 3 An exemplary physical architecture of a distributed radio access network (RAN) 300 according to aspects of the present disclosure is illustrated. A centralized core network unit (C-CU) 302 may host core network functions. The C-CU 302 may be centrally deployed. C-CU 302 functions may be offloaded (e.g., to Advanced Wireless Services (AWS)) to handle peak capacity.

[0051] A centralized RAN unit (C-RU) 304 may host one or more ANC functions. Optionally, the C-RU 304 may host core network functions locally. The C-RU 304 may have a distributed deployment. The C-RU 304 may be close to the network edge.

[0052] The DU 306 may host one or more TRPs (edge ​​node (EN), edge unit (EU), radio head (RH), smart radio head (SRH), etc.) The DU may be located at the edge of the network with radio frequency (RF) capabilities.

[0053] Figure 4 The diagram shows a BS 110 and a UE 120 (eg Figure 1 ), which may be used to implement various aspects of the present disclosure.

[0054] At BS 110, transmit processor 420 may receive data from data source 412 and control information from controller / processor 440. Control information may be for physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. Data may be for 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 for control command exchange between wireless nodes. MAC-CE may be carried in a shared channel such as a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), or a physical sidelink shared channel (PSSCH).

[0055] The processor 420 may process (e.g., encode and symbol map) data and control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a cell-specific reference signal (CRS). The transmit (TX) multiple-input multiple-output (MIMO) processor 430 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols (if applicable), and may provide an output symbol stream to a modulator (MOD) in transceivers 432a to 432t. Each modulator in transceivers 432a-432t may process a corresponding 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 up-convert) the output sample stream to obtain a downlink signal. The downlink signals from the modulators in transceivers 432a to 432t may be transmitted via antennas 434a to 434t, respectively.

[0056] At the UE 120, antennas 452a to 452r may receive downlink signals from the base station 110 and may provide received signals to demodulators (DEMODs) in transceivers 454a to 454r, respectively. Each demodulator in the transceivers 454a-454r may condition (e.g., filter, amplify, downconvert, and digitize) a corresponding received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. The MIMO detector 456 may obtain received symbols from all demodulators in the transceivers 454a to 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. The receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120 to the data sink 460, and provide decoded control information to the controller / processor 480.

[0057] On the uplink, at the UE 120, a transmit processor 464 may receive and process data from a data source 462 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 480 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 464 may also generate reference symbols for reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466 (if applicable), further processed by a demodulator (e.g., for SC-FDM, etc.) in the transceivers 454a through 454r, and transmitted to the base station 110. At the BS 110, uplink signals from the UE 120 may be received by the antennas 434, processed by the modulators in the transceivers 432a-432t, detected by the MIMO detector 436 (if applicable), and further processed by the receive processor 438 to obtain decoded data and control information transmitted by the UE 120. The receive processor 438 may provide the decoded data to a data sink 439 and the decoded control information to a controller / processor 440 .

[0058] Controllers / processors 440 and 480 may direct the operation at base station 110 and UE 120, respectively. Processor 440 and / or other processors and modules at BS 110 may perform or direct the execution of processes for the techniques described herein. Memories 442 and 482 may store data and program codes for BS 110 and UE 120, respectively. Scheduler 444 may schedule UEs for data transmission on the downlink and / or uplink.

[0059] Memories 442 and 482 may store data and program codes for BS 110a and UE 120a, respectively.A scheduler 444 may schedule UEs for data transmission on the downlink and / or uplink.

[0060] The various techniques and methods described herein may be performed using antenna 452, processors 466, 458, 464, and / or controller / processor 480 of UE 120a and / or antenna 434, processors 420, 430, 438, and / or controller / processor 440 of BS 110a. Figure 4 As shown, the controller / processor 440 of BS 110a has a beam manager 441 that performs beam refinement based on PRACH repetitions according to aspects described herein. Figure 4 As shown, according to aspects described herein, the controller / processor 480 of the UE 120a has a PRACH repetition manager 481 that sends PRACH repetitions corresponding to the determined RACH opportunities. Although shown at the controller / processor, other components of the UE 120a and BS 110a may be used to perform the operations described herein.

[0061] NR can use orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the downlink and uplink. OFDM and single carrier frequency division multiplexing (SC-FDM) divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also generally referred to as frequency modulation, frequency bins, etc. Each subcarrier can be modulated with data. Modulation symbols are sent in the frequency domain using OFDM, and modulation symbols are sent in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers can depend on the system bandwidth. The minimum resource allocation, called a resource block (RB), can be 12 consecutive subcarriers. The system bandwidth can also be divided into subbands. For example, a subband can cover multiple RBs. NR can support a basic subcarrier spacing (SCS) of 15KHz, and other SCSs (for example, 30kHz, 60kHz, 120kHz, 240kHz, etc.) can be defined relative to the basic SCS.

[0062] Figure 5A diagram 500 showing an example for implementing a communication protocol stack according to aspects of the present disclosure is illustrated. The communication protocol stack shown can be implemented by a device operating in a wireless communication system such as a 5G system (e.g., a system supporting uplink-based mobility). Diagram 500 illustrates a communication protocol stack, which includes a radio resource control (RRC) layer 510, a packet data convergence protocol (PDCP) layer 515, a radio link control (RLC) layer 520, a media access control (MAC) layer 525, and a physical (PHY) layer 530. In various examples, the layers of the protocol stack can be implemented as separate modules of software, parts of a processor or ASIC, parts of non-colocated devices connected by a communication link, or various combinations thereof. Colocated and non-colocated implementations can be used in, for example, a protocol stack of a network access device (e.g., AN, CU, and / or DU) or a UE.

[0063] The first option 505-a illustrates a split implementation of the protocol stack, wherein the implementation of the protocol stack is performed on a centralized network access device (e.g., Figure 2 ANC 202 in ) and distributed network access equipment (e.g., Figure 2 In the first option 505-a, the RRC layer 510 and the PDCP layer 515 may be implemented by a central unit, and the RLC layer 520, the MAC layer 525, and the PHY layer 530 may be implemented by the DU. In various examples, the CU and the DU may be collocated or non-collocated. The first option 505-a may be useful in macro cell, micro cell, or pico cell deployments.

[0064] The second option 505-b shows a unified implementation of the protocol stack, wherein the protocol stack is implemented in a single network access device. In the second option, each of the RRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525, and the PHY layer 530 can be implemented by the AN. The second option 505-b can be used for, for example, femtocell deployment.

[0065] Regardless of whether the network access device implements part or all of the protocol stack, the UE can implement the entire protocol stack as shown in 505-c (e.g., RRC layer 510, PDCP layer 515, RLC layer 520, MAC layer 525, and PHY layer 530).

[0066] The embodiments discussed herein may include various spacing and timing deployments. For example, in LTE, the basic transmission time interval (TTI) or packet duration is a 1ms subframe. In NR, the subframe is still 1ms, but the basic TTI is called a time slot. The subframe includes a variable number of time slots (e.g., 1, 2, 4, 8, 16 time slots) depending on the subcarrier spacing. NR RBs are 12 consecutive frequency subcarriers. NR can support a basic subcarrier spacing of 15KHz, and other subcarrier spacings can be defined relative to the basic subcarrier spacing, for example, 30kHz, 60kHz, 120kHz, 240kHz, etc. The symbol and time slot lengths are proportional to the subcarrier spacing. The CP length also depends on the subcarrier spacing.

[0067] Figure 6 6 is a diagram showing an example of a frame format 600 for NR. The transmission timeline of each of the downlink and uplink may be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be divided into 10 subframes, each of which has 1 ms and 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 subcarrier spacing. Each slot may include a variable number of symbol periods (e.g., 7, 12, or 14 symbols) depending on the SCS. The symbol periods in each slot may be assigned an index. The subslot structure may refer to a transmission time interval having a duration less than a slot (e.g., 2, 3, or 4 symbols). Each symbol in a slot may indicate a link direction (e.g., DL, UL, or flexible) for data transmission, and the link direction of each subframe may be switched dynamically. The link direction may be based on the slot format. Each slot may include DL / UL data and DL / UL control information.

[0068] In NR, synchronization signal (SS) blocks (SSBs) are transmitted. In certain aspects, SSBs may be transmitted in bursts, where each SSB in a burst corresponds to a different beam direction for UE-side beam management (e.g., including beam selection and / or beam refinement). An SS block includes a PSS, SSS, and two symbol PBCHs. An SS block may be transmitted in fixed slot locations, such as Figure 6Symbols 0-3 shown. PSS and SSS can be used by UE for cell search and acquisition. PSS can provide half-frame timing, and SS can provide CP length and frame timing. PSS and SSS can provide cell identification. PBCH carries some basic system information, such as downlink system bandwidth, timing information within a radio frame, SS burst set period, system frame number, etc. Additional system information, such as remaining minimum system information (RMSI), system information block (SIB), other system information (OSI), can be sent on the physical downlink shared channel (PDSCH) in certain subframes. SSB can be sent up to sixty-four times, for example, for mmWave, up to sixty-four different beam directions are used. Multiple transmissions of SSB are called SS burst sets. SSBs in an SS burst set can be sent in the same frequency region, and SSBs in different SS burst sets can be sent in different frequency regions.

[0069] Control Resource Set (CORESET)

[0070] A control resource set (CORESET) for an OFDMA system (e.g., a communication system that uses an OFDMA waveform to send a PDCCH) may include one or more sets of control resources (e.g., time and frequency resources) within the system bandwidth that are configured to communicate the PDCCH. Within each CORESET, one or more search spaces (e.g., a common search space (CSS), a UE-specific search space (USS), etc.) may be defined for a given UE. A search space is generally an area or portion in which a communication device (e.g., a UE) may search for control information.

[0071] According to various aspects of the present disclosure, a CORESET is a set of time and frequency domain resources defined in units of resource element groups (REGs). Each REG may include a fixed number (e.g., twelve) of tones in a symbol period (e.g., a symbol period of a time slot), wherein one tone in a symbol period is referred to as a resource element (RE). A fixed number of REGs may be included in a control channel element (CCE). A CCE set may be used to send a new radio PDCCH (NR-PDCCH), wherein different numbers of CCEs in a set are used to send NR-PDCCH using different aggregation levels. Multiple CCE sets may be defined as a search space for a UE, so that a Node B or other base station may send an NR-PDCCH to a UE by sending an NR-PDCCH in a CCE set, which is defined as a decoding candidate within the search space of the UE, and the UE may receive the NR-PDCCH by searching in the search space of the UE and decoding the NR-PDCCH sent by the Node B.

[0072] The operating characteristics of a Node B or other base station in an NR communication system may depend on the frequency range (FR) in which the system operates. The frequency range may include one or more operating bands (e.g., "n1" band, "n2" band, "n7" band, and "n41" band), and the communication system (e.g., one or more Node Bs and UEs) may operate in one or more operating bands. Frequency ranges and operating bands are described in more detail in "Base Station (BS) Radio Transmission and Reception" TS 38.104 (Release 15), which is available from the 3GPP website.

[0073] As described above, a CORESET is a collection of time domain and frequency domain resources. A CORESET can be configured to communicate a PDCCH within the system bandwidth. The UE can determine the CORESET and monitor the CORESET for control channels. During initial access, the UE can identify the initial CORESET (CORESET#0) configuration based on a field in a mask information block (MIB) (e.g., pdcchConfigSIB1). This initial CORESET can then be used to configure the UE (e.g., configured with other CORESETs and / or bandwidth portions) via dedicated (UE-specific) signaling. When the UE detects a control channel in a CORESET, the UE attempts to decode the control channel and communicate with the transmitting BS (e.g., transmitting cell) based on the control data provided in the control channel (e.g., sent via the CORESET).

[0074] According to various aspects of the present disclosure, when a UE is connected to a cell (or BS), the UE may receive a master information block (MIB). The MIB may be in a synchronization signal and physical broadcast channel (SS / PBCH) block on a sync grater (sync grater) (e.g., in the PBCH of the SS / PBCH block). In some scenarios, the sync grater may correspond to the SSB. Based on the frequency of the sync grater, the UE may determine the operating frequency band of the cell. Based on the operating frequency band of the cell, the UE may determine the minimum channel bandwidth and the subcarrier spacing (SCS) of the channel. The UE may then determine an index based on the MIB (e.g., four bits in the MIB conveying an index in the range 0-15).

[0075] Given this index, the UE can look up or locate the CORESET configuration (this initial CORESET configured via the MIB is generally referred to as CORESET#0). This can be done from one or more tables of CORESET configurations. These configurations (including single table scenarios) may include various subsets of indices indicating valid CORESET configurations for various combinations of minimum channel bandwidth and SCS. In some arrangements, each combination of minimum channel bandwidth and SCS may be mapped to a subset of indices in the table.

[0076] Alternatively or additionally, the UE may select a search space CORESET configuration table from several CORESET configuration tables. These configurations may be based on the minimum channel bandwidth and the SCS. The UE may then look up the CORESET configuration (e.g., Type0-PDCCH search space CORESET configuration) from the selected table based on the index. After determining the CORESET configuration (e.g., from a single table or a selected table), the UE may then determine the CORESET to monitor based on the location (in time and frequency) of the SS / PBCH blocks and the CORESET configuration (as described above).

[0077] Figure 8 An exemplary transmission resource mapping 800 according to aspects of the present disclosure is shown. In the exemplary mapping, a BS (e.g., Figure 1 BS 110a) shown in FIG. sends SS / PBCH block 802. The SS / PBCH block includes a MIB that conveys an index to a table that relates the time and frequency resources of CORESET 804 to the time and frequency resources of the SS / PBCH block.

[0078] The BS may also send control signaling. In some scenarios, the BS may also send control signaling to the UE (e.g., Figure 1 806). The BS may then send a PDCCH to the UE 120 shown in FIG. 806. The PDCCH may schedule a PDSCH 806. The BS may then send a PDSCH to the UE. The UE may receive a MIB in an SS / PBCH block, determine an index, look up a CORESET configuration based on the index, and determine a CORESET based on the CORESET configuration and the SS / PBCH block. The UE may then monitor the CORESET, decode the PDCCH in the CORESET, and receive a PDSCH allocated by the PDCCH.

[0079] Different CORESET configurations may have different parameters defining the corresponding CORESET. For example, each configuration may indicate the number of resource blocks (e.g., 24, 48, or 96), the number of symbols (e.g., 1-3), and an offset indicating a location in frequency (e.g., 0-38 RBs).

[0080] QCL port and TCI status

[0081] In many cases, it is important for a user equipment (UE) to know which assumptions it can make on channels corresponding to different transmissions. For example, the UE may need to know which reference signals it can use to estimate the channel in order to decode a transmitted signal (e.g., the Physical Downlink Control Channel (PDCCH) or the Physical Downlink Shared Channel (PDSCH)). It may also be important for the UE to be able to report relevant channel state information (CSI) to the BS (gNB) for scheduling, link adaptation and / or beam management purposes. In 5G New Radio (NR), the concepts of Quasi Co-Location (QCL) and Transmission Configuration Indicator (TCI) status are used to convey information about these assumptions.

[0082] The QCL assumption is generally defined based on channel properties. According to 3GPP TS 38.214, "Two antenna ports are said to be quasi-co-located if the properties of the channel conveying symbols on one antenna port can be inferred from the channel conveying symbols on the other antenna port." Different reference signals can be considered to be quasi-co-located ("QCL'd") if the receiver (e.g., UE) is able to apply channel properties determined by detecting the first reference signal to help detect the second reference signal. The TCI state generally includes the configuration of the QCL relationship between, for example, the DL RS in a CSI reference signal (CSI-RS) set and the PDSCH demodulation reference signal (DMRS) port.

[0083] In some cases, the UE may be configured with up to M TCI-States. The configuration of the M TCI-States may be implemented via higher layer signaling, and the UE may be signaled based on the detected PDCCH to decode the PDSCH, where the DCI indicates one of the TCI states. Each configured TCI state may include an RS set TCI-RS-SetConfig, which indicates different QCL assumptions between certain source and target signals.

[0084] Fig. 9 An example of association of DL reference signals with corresponding QCL types that may be indicated by TCI-RS-SetConfig is illustrated.

[0085] exist Fig. 9In the example of , the source reference signal (RS) is indicated in the top block and is associated with the target signal indicated in the bottom block. In this case, the target signal generally refers to a signal whose channel properties can be inferred by measuring the channel properties of the associated source signal. As described above, the UE can use the source RS to determine various channel parameters according to the associated QCL type, and use those various channel properties (determined based on the source RS) to process the target signal. The target RS does not necessarily need to be the DMRS of the PDSCH, but can be any other RS: physical uplink shared channel (PUSCH) DMRS, CSI-RS, tracking reference signal (TRS) and sounding reference signal (SRS).

[0086] As shown, each TCI-RS-SetConfig includes parameters. These parameters can, for example, configure the (one or more) quasi-colocation relationships between the reference signals in the RS set of the PDSCH and the DM-RS port group. The RS set contains references to one or two DL RSs and the associated quasi-colocation type (QCL-type) of each DL RS configured by the higher layer parameter QCL-Type.

[0087] like Fig. 9 As shown, for the case of two DL RSs, the QCL type can take various arrangements. For example, the QCL type can be different regardless of whether the reference is to the same DL RS or to different DL RSs. In the example shown, for P-TRS, SSB is associated with C-type QCL, while for beam management, CSI-RS (CSIRS-BM) is associated with D-type QCL.

[0088] The QCL information and / or type may depend on or be a function of other information in some scenarios. For example, the quasi-co-location (QCL) type indicated to the UE may be based on a higher layer parameter QCL-Type and may be one or a combination of the following types:

[0089] QCL-TypeA: {Doppler shift, Doppler spread, average delay, delay spread},

[0090] QCL-TypeB: {Doppler shift, Doppler spread},

[0091] QCL-TypeC: {average delay, Doppler shift}, and

[0092] QCL-TypeD: {spatial Rx parameters},

[0093] The spatial QCL assumption (QCL-type D) may be used to help the UE select an analog Rx beam (eg, during a beam management procedure). For example, the SSB resource indicator may indicate that the same beam for a previous reference signal should be used for subsequent transmissions.

[0094] During the initial access of the UE (e.g., via a field in the MIB), the initial CORESET in the NR (e.g., CORESET ID 0 or simply CORESET#0) can be identified. The ControlResourceSet information element (CORESET IE) sent via radio resource control (RRC) signaling can convey information about the CORESET configured for the UE. The CORESET IE generally includes the CORESET ID, an indication of the frequency domain resources allocated to the CORESET (e.g., the number of RBs), the continuous duration of the CORESET in multiple symbols, and the transmission configuration indicator (TCI) status.

[0095] As described above, a subset of TCI states provides a quasi-co-location (QCL) relationship between DL RS and PDCCH demodulation RS (DMRS) ports in a RS set (e.g., a TCI set). A specific TCI state for a given UE (e.g., for unicast PDCCH) can be communicated to the UE by a media access control (MAC) control element (MAC-CE). The specific TCI state is generally selected from a set of TCI states communicated by a CORESET IE, where the initial CORESET (CORESET#0) is generally configured via the MIB.

[0096] Search space information may also be provided via RRC signaling. For example, the Search Space IE is another RRC IE that defines how and where to search for PDCCH candidates for a given CORESET. Each search space is associated with one CORESET. The Search Space IE identifies the search space configured for the CORESET by the Search Space ID. In one aspect, the Search Space ID associated with CORESET#0 is Search Space ID#0. The search space is generally configured via PBCH (MIB).

[0097] Exemplary RACH Procedure

[0098] The Random Access Channel (RACH) is so named because it refers to a wireless channel (medium) that can be shared by multiple user equipments (UEs) and used by the UEs to (randomly) access the network for communication. For example, RACH can be used for call establishment and access to the network for data transmission. In some cases, RACH can be used for initial access to the network when the UE switches from Radio Resource Control (RRC) connection idle mode to active mode, or when switching in RRC connected mode. In addition, RACH can be used for downlink (DL) and / or uplink (UL) data arrival when the UE is in RRC idle or RRC inactive mode, and when reestablishing a connection with the network.

[0099] Typically, the UE monitors for Synchronization Signal Block (SSB) transmissions, which are sent (by the gNB using different beams) and are associated with a limited set of time / frequency resources that define RACH Opportunities (ROs). As will be described in more detail below, upon detecting an SSB, the UE can select the RO associated with that SSB for msgA transmissions. A limited set of ROs can help reduce the monitoring overhead (blind decoding) of the base station. In other words, by associating a limited set of ROs with SSB transmissions, the gNB knows when, where, and in what direction to "listen" for RACH transmissions from the UE.

[0100] Fig.10 1000 is a timing (or "call flow") diagram for illustrating an exemplary four-step RACH process in accordance with certain aspects of the present disclosure. A first message (e.g., MSG1) may be sent from UE 120 to BS 110 on a physical random access channel (PRACH). In this case, MSG1 may include only a RACH preamble. BS 110 may respond with a second message (e.g., MSG2, a random access response (RAR) message) that may include an identifier (ID) of the RACH preamble, a timing advance (TA), an uplink grant, a cell radio network temporary identifier (C-RNTI), and a fallback indicator. The RAR message may include a physical downlink control channel (PDCCH) communication that includes control information for subsequent communications on a physical downlink shared channel (PDSCH), as shown. In response to the RAR message, a third message (e.g., MSG3) is sent from UE 120 to BS 110 on PUSCH. The third message may include one or more of an RRC connection request, a tracking area update request, a system information request, a positioning position or positioning signal request, or a scheduling request. BS 110 then responds with a fourth message (MSG4), which may include a contention resolution message. In contention-free random access, a preamble is assigned to the UE and the last two messages are skipped.

[0101] As described above, the UE transmits a preamble through the gNB on the RACH opportunity associated with the previous SSB transmission. The RACH procedure is used for different purposes, including initial access, synchronization, uplink scheduling request, beam recovery, etc. The RACH configuration of a cell generally specifies the number of SSB time indices per RACH time / frequency opportunity (which can be one, less than one, or greater than one).

[0102] In some cases, to speed up access, a two-step RACH procedure may be supported. As its name implies, the two-step RACH procedure effectively "collapses" the four messages of the four-step RACH procedure into two "enhanced" messages.

[0103] A first enhancement message (msgA) may be sent from the UE to the BS. In some aspects, msgA includes some or all of the information from the first message (e.g., MSG1) and the third message (e.g., MSG3) of the four-step RACH process, thereby effectively combining MSG1 and MSG3. For example, msgA may include MSG1 and MSG3 multiplexed together, such as using one of time division multiplexing or frequency division multiplexing. In some aspects, msgA includes a RACH preamble and a payload for random access. The msgA payload may, for example, include a UE-ID and other signaling information (e.g., a buffer status report (BSR)) or a scheduling request (SR). The BS may respond with a RAR message (e.g., msgB), which may effectively combine the above-mentioned second message (e.g., MSG2) and the fourth message (e.g., MSG4). For example, MsgB may include an ID of the RACH preamble, a timing advance (TA), a backoff indicator, a contention resolution message, an UL / DL grant, and a transmit power control (TPC) command.

[0104] The techniques described herein may utilize both 4-step and 2-step RACH procedures and mechanisms.

[0105] Example PRACH repetition and receive beam scanning

[0106] Certain aspects of the present disclosure provide techniques for network-side beam refinement based on physical random access channel (PRACH) repetition. The beam refinement generated by beam scanning can be used to receive a third message (e.g., MSG3) and / or send a second message (e.g., MSG2) in a four-step random access channel (RACH) process.

[0107] These techniques can improve system performance because MSG2 and MSG3 are the bottleneck for mmWave 5G coverage. In some cases, the RACH process may create a bottleneck because no narrowband is available and therefore the RACH process relies on a wide broadcast beam based on a synchronization signal block (SSB) beam, resulting in reduced beam gain. With reduced beam gain, coverage issues arise. One way to address coverage issues is to introduce coverage enhancements through repetition and / or beam refinement.

[0108] Fig.11 1 is a flow diagram illustrating example operations 1100 for wireless communications by a network entity. Operations 1100 may be performed, for example, by a base station (BS) 110 (e.g., a gNB).

[0109] Operations 1100 begin at 1102, where a network entity determines resources to use to monitor a PRACH transmission sent from a user equipment (UE) as part of a random access channel (RACH) procedure.

[0110] In some aspects, at 1104, the network entity may configure the UE to send the PRACH repetition using the determined resources if an SSB-based reference signal received power (RSRP) measurement is less than a threshold.

[0111] In some aspects, at 1106, the network entity may signal to the UE an indication of time resources for PRACH repetitions.

[0112] In some aspects, at 1108, the network entity may detect PRACH repetitions separately for each refined beam scan.

[0113] In some aspects, at 1110, the network entity may detect PRACH repetitions after soft combining received signals on different refined beams of the refined one or more beams.

[0114] In some aspects, at 1112, the network entity may receive PRACH repetitions from the UE using the determined resources when one or more conditions are met.

[0115] At 1114, the network entity performs receive beam scanning when receiving the PRACH repetitions sent using the determined resources.

[0116] At 1116, the network entity refines the one or more beams using the results of the beam scanning and selects a refined beam from the refined one or more beams.

[0117] At 1118, the network entity uses the selected refined beam to at least one of receive a subsequent message from the UE as part of a RACH procedure or send a subsequent message to the UE as part of a RACH procedure.

[0118] Fig.12 is a flow chart illustrating example operations 1200 for wireless communications by a UE and may be considered to be a flowchart of Fig.11 For example, the UE 120 may perform the following operations in conjunction with: Fig.11 The BS 110 of operation 1100 performs operation 1200 .

[0119] Operations 1200 begin at 1202, where the UE determines a RACH opportunity associated with one or more synchronization signal block (SSB) beams for transmitting a PRACH transmission with repetitions.

[0120] In some aspects, at 1204, the UE may receive signaling indicating time resources for PRACH repetitions.

[0121] At 1206, if one or more conditions are met, the UE sends the PRACH repetition using resources corresponding to the determined RACH opportunity.

[0122] according to Fig.11 and Fig.12 The PRACH repetition and receive beam scanning of operations 1100 and 1200 and the associated beam refinement for MSG3 and / or MSG2 may be referred to in Fig.13 For understanding, refer to the exemplary flow chart of FIG.

[0123] like Fig.13 As shown, the gNB configures the UE for PRACH repetitions. In some cases, the configuration may indicate resources for PRACH repetitions and / or may indicate one or more conditions that trigger the UE to send PRACH repetitions (e.g., conditions indicating that beam refinement may be beneficial).

[0124] As shown, the UE detects the condition that triggers PRACH repetition and therefore sends the PRACH repetition to the gNB. The gNB performs receive beam scanning for PRACH repetition and selects the refined beam. At a later time, the network entity uses the refined beam to send MSG2 to the UE and / or receive MSG3 from the UE.

[0125] Certain aspects of the present disclosure relate to implementing a combined control element (CE) for MSG1, MSG2, and MSG3 by repeating PRACH repetition and / or receive beam scanning. PRACH repetition and / or receive beam scanning, especially PRACH repetition and / or receive beam scanning of MSG1, can be used for beam refinement of MSG2 and / or MSG3.

[0126] In certain aspects, the UE may use PRACH repetitions on specific PRACH time resources dedicated for PRACH repetitions. The gNB performs receive beam scanning (e.g., using a different receive (Rx) beam for each repetition) on the PRACH repetitions to refine the beams (e.g., the Rx beam for MSG3 reception and / or the corresponding transmit (Tx) beam for MSG2 transmission).

[0127] In some cases, the use of dedicated PRACH resources (i.e., dedicated for PRACH repetitions) may depend on the UE's synchronization signal beam (SSB) based reference signal received power (RSRP) measurement. If the SSB based RSRP measurement is less than a certain threshold, the UE may use PRACH repetitions on repeated dedicated resources. In some aspects, the time resources used for PRACH repetitions may be configured by the remaining minimum system information (RMSI) or some other system information (SI). In some aspects, the threshold for RSRP measurement for selecting PRACH repetitions may be configured by the RMSI.

[0128] In some cases, the gNB may decide to detect PRACH repetitions separately for each refined beam scan. In some cases, the gNB may detect PRACH repetitions after soft combining the received signals on different refined beams and selecting a refined beam (e.g., for MSG3 reception and / or MSG2 transmission) based on comparing the RSRP of different repetitions.

[0129] Fig.14 The diagrams may include instructions configured to perform operations for the techniques disclosed herein (such as, Fig.11 1400 includes a communication device 1400 that includes various components (e.g., corresponding to means plus function components) of the operations illustrated in FIG. 1400 . The communication device 1400 includes a processing system 1402 coupled to a transceiver 1408 (e.g., a transmitter and / or a receiver). The transceiver 1408 is configured to transmit and receive signals for the communication device 1400, such as the various signals described herein, via an antenna 1410. The processing system 1402 may be configured to perform processing functions of the communication device 1400, including processing signals received and / or transmitted by the communication device 1400.

[0130] The processing system 1402 includes a processor 1404 coupled to a computer-readable medium / memory 1412 via a bus 1406. In some aspects, the computer-readable medium / memory 1412 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1404, cause the processor 1404 to perform Fig.11, or other operations for performing the various techniques for beam refinement via PRACH repetitions discussed herein. In certain aspects, the computer-readable medium / memory 1412 stores code 1414 for determining resources used to monitor physical random access channel (PRACH) transmissions sent from a user equipment (UE) as part of a random access channel (RACH) procedure; code 1416 for performing receive beam scanning when receiving PRACH repetitions sent using the determined resources; circuitry 1418 for using the results of the receive beam scanning to refine one or more beams and select a refined beam from the refined one or more beams; and circuitry 1420 for using the selected refined beam to at least one of receive a subsequent message from the UE as part of the RACH procedure or send a subsequent message to the UE as part of the RACH procedure. In certain aspects, the computer-readable medium / memory 1412 may store code 1422 for receiving PRACH repetitions from the UE using the determined resources when one or more conditions are met. In certain aspects, the computer-readable medium / memory 1412 may store code 1424 for configuring the UE to send PRACH repetitions using determined resources if the SSB-based RSRP measurement is less than a threshold. In certain aspects, the computer-readable medium / memory 1412 may store code 1426 for signaling to the UE an indication of time resources for PRACH repetitions. In certain aspects, the computer-readable medium / memory 1412 may store code 1428 for detecting PRACH repetitions separately for each refined beam scan. In certain aspects, the computer-readable medium / memory 1412 may store code 1430 for detecting PRACH repetitions after soft combining received signals on different refined beams in the refined one or more beams. In certain aspects, the processor 1404 has circuitry configured to implement the code stored in the computer-readable medium / memory 1412. Processor 1404 includes circuitry 1434 for determining resources to monitor PRACH transmissions sent from a UE as part of a RACH procedure; circuitry 1436 for performing receive beam scanning when receiving PRACH repetitions sent using the determined resources; circuitry 1438 for refining one or more beams using the results of the receive beam scanning and selecting a refined beam from the refined one or more beams; and circuitry 1440 for using the selected refined beam to at least one of receive a subsequent message from the UE as part of a RACH procedure or send a subsequent message to the UE as part of a RACH procedure. In certain aspects, processor 1404 may include circuitry 1442 for receiving PRACH repetitions from the UE using the determined resources when one or more conditions are met.In certain aspects, processor 1404 may include circuitry 1444 for configuring the UE to transmit PRACH repetitions using determined resources if the SSB-based RSRP measurement is less than a threshold. In certain aspects, processor 1404 may include circuitry 1446 for signaling to the UE an indication of time resources for PRACH repetitions. In certain aspects, processor 1404 may include circuitry 1448 for detecting PRACH repetitions separately for each refined beam scan. In certain aspects, processor 1404 may include circuitry 1450 for detecting PRACH repetitions after soft combining received signals on different refined beams in the refined one or more beams.

[0131] For example, means for transmitting (or means for outputting for transmitting) may include Figure 2 The transmitter and / or antenna 234 and / or Fig.14 The circuit 1440 of the communication device 1400 shown in FIG. The means for receiving (or the means for obtaining) may include Figure 2 The receiver and / or antenna 234 and / or Fig.14 1400 of the communication device 1400 shown in FIG. 1440. The means for communicating may include a transmitter, a receiver, or both. The means for generating, the means for executing, the means for determining, the means for taking action, the means for determining, and the means for coordinating may include a processing system, which may include one or more processors, such as Figure 2 The transmit processor 220, TX MIMO processor 230, receive processor 238 and / or controller / processor 240 and / or BS 110a shown in FIG. Fig.14 The processing system 1402 of the communication device 1400 in FIG.

[0132] Fig.15 The diagrams may include instructions configured to perform operations for the techniques disclosed herein (such as, Fig.12 1500 includes a communication device 1500 that includes various components (e.g., corresponding to means plus function components) of the operations illustrated in FIG. 1500 . The communication device 1500 includes a processing system 1502 coupled to a transceiver 1508 (e.g., a transmitter and / or a receiver). The transceiver 1508 is configured to transmit and receive signals for the communication device 1500, such as the various signals described herein, via an antenna 1510. The processing system 1502 may be configured to perform processing functions of the communication device 1500, including processing signals received and / or transmitted by the communication device 1500.

[0133] The processing system 1502 includes a processor 1504 coupled to a computer-readable medium / memory 1512 via a bus 1506. In some aspects, the computer-readable medium / memory 1512 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1504, cause the processor 1504 to perform Fig.11 , or other operations for performing various techniques for beam refinement via PRACH repetition discussed herein. In certain aspects, the computer-readable medium / memory 1512 stores code 1514 for determining a RACH opportunity associated with one or more SSB beams for sending a PRACH transmission with repetitions; and code 1516 for sending the PRACH repetitions using resources corresponding to the determined RACH opportunity if one or more conditions are met. In certain aspects, the computer-readable medium / memory 1512 may store code 1518 for receiving a signaling notification indicating time resources for PRACH repetitions. In certain aspects, the processor 1504 has circuitry configured to implement the code stored in the computer-readable medium / memory 1512. The processor 1504 includes circuitry 1524 for determining a RACH opportunity associated with one or more SSB beams for sending a PRACH transmission with repetitions; and circuitry 1526 for sending the PRACH repetitions using resources corresponding to the determined RACH opportunity if one or more conditions are met. In certain aspects, processor 1504 may include circuitry 1528 for receiving signaling indicating time resources for PRACH repetitions.

[0134] For example, means for transmitting (or means for outputting for transmitting) may include Figure 2 The transmitter unit 254 and / or antenna 252 and / or Fig.15 The circuit 1526 of the communication device 1500 in FIG. The means for receiving (or the means for obtaining) may include Figure 2 1 and / or antenna 252 of UE 120a shown in FIG. 1 . The means for communicating may include a transmitter, a receiver, or both. The means for generating, the means for executing, the means for determining, the means for taking action, the means for determining, the means for coordinating may include a processing system, which may include one or more processors, such as, Figure 2 The receive processor 258, transmit processor 264, TX MIMO processor 266 and / or controller / processor 280 and / or UE 120a shown in FIG. Fig.15 The processing system 1502 of the communication device 1500 in FIG.

[0135] Exemplary Aspects

[0136] Examples of implementations are described in the following numbered aspects:

[0137] Aspect 1: A method for wireless communications by a network entity, comprising: determining resources used to monitor a physical random access channel (PRACH) transmission sent from a user equipment (UE) as part of a random access channel (RACH) procedure; performing receive beam scanning when receiving PRACH repetitions sent using the determined resources; using the results of the receive beam scanning to refine one or more beams and select a refined beam from the refined one or more beams; and using the selected refined beam to at least one of receive a subsequent message from the UE as part of the RACH procedure or send a subsequent message to the UE as part of the RACH procedure.

[0138] Aspect 2: The method according to aspect 1 further includes: when one or more conditions are met, receiving PRACH repetition from the UE using the determined resources.

[0139] Aspect 3: The method according to Aspect 2, wherein the one or more conditions are related to reference signal received power (RSRP) measurement based on a synchronization signal block (SSB).

[0140] Aspect 4: The method according to Aspect 3 further includes: configuring the UE to: send PRACH repetition using the determined resources if the SSB-based RSRP measurement is less than a threshold.

[0141] Aspect 5: The method according to aspect 4, wherein configuring the UE with the threshold comprises configuring the UE with the threshold via at least one of: remaining minimum system information (RMSI); or some other system information (SI).

[0142] Aspect 6: The method according to any one of aspects 1-5 further comprises signaling an indication of time resources for PRACH repetition to the UE.

[0143] Aspect 7: The method according to aspect 6, wherein the signaling notification includes at least one of the following: remaining minimum system information (RMSI); or some other system information (SI).

[0144] Aspect 8: The method according to any one of aspects 1-7, further comprising detecting the PRACH repetition separately for each refined beam scan.

[0145] Aspect 9: The method according to any one of aspects 1-8, further comprising: detecting the PRACH repetition after soft combining received signals on different refined beams among the refined one or more beams.

[0146] Aspect 10: The method according to any one of aspects 1-9, wherein selecting a refined beam from the refined one or more beams comprises selecting the refined beam based on comparing reference signal received power (RSRP) for different PRACH repetitions.

[0147] Aspect 11: A method according to any one of Aspects 1-10, wherein the refined one or more beams are a subset of a synchronization signal block (SSB) beam set.

[0148] Aspect 12: The method according to any one of aspects 1-11, wherein the resource corresponds to one or more RACH opportunities.

[0149] Aspect 13: A method for wireless communication by a user equipment (UE), comprising: determining a random access channel (RACH) opportunity associated with one or more synchronization signal block (SSB) beams for sending a physical random access channel (PRACH) transmission with repetitions; and if one or more conditions are met, using resources corresponding to the determined RACH opportunity to send PRACH repetitions.

[0150] Aspect 14: The method according to Aspect 13, wherein the one or more conditions are related to SSB-based reference signal received power (RSRP) measurement.

[0151] Aspect 15: The method according to Aspect 14, wherein sending the PRACH repetition comprises: if the SSB-based RSRP measurement is less than a threshold, sending the PRACH repetition using resources corresponding to the determined RACH opportunity.

[0152] Aspect 16: The method according to aspect 15, wherein the threshold is configured via at least one of: remaining minimum system information (RMSI); or some other SI.

[0153] Aspect 17: The method according to any one of aspects 13-16, further comprising receiving a signaling notification indicating time resources for PRACH repetition.

[0154] Aspect 18: The method according to Aspect 17, wherein the signaling notification includes at least one of the following: remaining minimum system information (RMSI); or some other system information (SI).

[0155] Aspect 19: An apparatus comprising means for performing the method of any one of aspects 1 to 18.

[0156] Aspect 20: 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 18.

[0157] Aspect 21: A computer-readable medium for wireless communication having computer executable code stored thereon, which, when executed by at least one processor, causes an apparatus to perform the method of any one of aspects 1 to 18.

[0158] The techniques described herein can 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), and other networks. The terms "network" and "system" are generally used interchangeably. A CDMA network can implement radio technologies such as Universal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. Cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA system can implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as NR (e.g., 5GRA), 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 part of Universal Mobile Telecommunications System (UMTS).

[0159] LTE and LTE-A are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, 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 an emerging wireless communication technology under development).

[0160] In 3GPP, the term "cell" can refer to the coverage area of ​​a Node B (NB) and / or a Node B subsystem serving that coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and next generation Node B (gNB), new radio base station (NR BS), 5G NB, access point (AP) or transmission reception point (TRP) are used interchangeably.

[0161] A base station (BS) may provide communication coverage for a macro cell, a micro cell, a femto cell, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., a radius of several thousand meters) and may allow unrestricted access to UEs with service subscriptions. A micro cell may cover a relatively small geographic area and may allow unrestricted access to UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow limited access to UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a micro cell may be referred to as a micro BS. A BS for a femto cell may be referred to as a femto BS or a home BS.

[0162] UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a customer premises equipment (CPE), a cellular phone, a 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 computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical device, a biometric sensor / device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), an in-vehicle component or sensor, a smart meter / sensor, an industrial manufacturing equipment, a global positioning system device, a reality device, an augmented reality device (augmented reality (AR), extended reality (XR), or virtual reality (VR)), or any other suitable device configured to communicate via a wired medium.

[0163] Some UEs may be considered as machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which may communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node may, for example, provide connectivity to 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 as Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0164] In some examples, access to the air interface can be scheduled. The scheduling entity (e.g., BS) allocates resources for communication between some or all devices and equipment within its service area or cell. The scheduling entity can be responsible for scheduling, allocating, reconfiguring and releasing resources for one or more subordinate entities. That is, for scheduling communications, subordinate entities can utilize resources allocated by the scheduled entity. The base station is not the only entity that can be used as a scheduling entity. In some examples, the UE can be used as a scheduling entity, and resources can be scheduled for one or more subordinate entities (e.g., one or more other UEs), and other UEs can utilize the resources scheduled by the UE for wireless communication. In some examples, the UE can act as a scheduling entity in a peer-to-peer (P2P) network and / or a mesh network. In the mesh network example, in addition to communicating with the scheduling entity, the UEs can also communicate directly with each other.

[0165] The method disclosed herein includes one or more steps or actions for implementing the method. Method steps and / or actions can be interchangeable with each other. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions can be modified.

[0166] 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 with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0167] As used herein, the term "determining" includes a variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, a 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.

[0168] The previous description is provided to enable those skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Unless otherwise specified, reference to an element in the singular is not intended to mean "one and only one", but rather "one or more". Unless otherwise specifically stated, the term "some" refers to one or more. All structural and functional equivalents of the elements throughout the various aspects described in this disclosure that are known or will be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, none of the contents disclosed herein are intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims. The elements of a claim should not be interpreted as being in accordance with the provisions of 35 U.S.C. § 112 (f), unless the element is explicitly stated using the phrase "for ... component", or in the case of a method claim, the element is stated using the phrase "for ... step".

[0169] The various operations of the above method can be performed by any suitable component capable of performing the corresponding function. The component may include various hardware and / or software components and / or modules, including but not limited to circuits, digital signal processors (DSPs), application specific integrated circuits (ASICs), or processors (e.g., general or special programming processors). In general, where there are operations shown in the figure, those operations may have corresponding components plus functional components with similar numbers.

[0170] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or performed with a general purpose processor, a DSP, an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0171] If implemented in hardware, an exemplary hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. The bus may include any number of interconnecting buses and bridges, depending on the specific application and overall design constraints of the processing system. The bus may connect various circuits 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. The network adapter may be used to implement the signal processing functions of the PHY layer. In a user terminal (see Figure 1 ), a user interface (e.g., a keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, etc., which are well known in the art and will not be described further. The processor may be implemented with one or more general 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 best to implement the described functions of the processing system, which depends on the specific application and the overall design constraints imposed on the entire system.

[0172] If implemented in software, the function may be stored or sent as one or more instructions or codes on a computer-readable medium. Software should be broadly interpreted as meaning instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or other. Computer-readable media include both computer storage media and communication media, and communication media include any medium that facilitates the transmission of computer programs from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on a machine-readable storage medium. A computer-readable storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. In an alternative, the storage medium may be integrated with the processor. As an example, a machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon separated from a wireless node, all of which may be accessed by a processor through a bus interface. Alternatively or in addition, a machine-readable medium or any part thereof may be integrated into a processor, such as in the case of having a cache memory and / or a general register stack. As an example, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read only memory), PROM (programmable read only memory), EPROM (erasable programmable read only memory), EEPROM (electrically erasable programmable read only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. The machine-readable medium may be embodied in a computer program product.

[0173] A software module may include a single instruction or many instructions, and may be distributed over several different code segments, in different programs, and across multiple storage media. A computer-readable medium may include multiple software modules. A software module includes instructions that cause a processing system to perform various functions when executed by a device such as a processor. A software module may include a sending module and a receiving module. Each software module may reside in a single storage device or be distributed over multiple storage devices. As an example, when a triggering event occurs, a software module may be loaded from a hard drive into a RAM. During the execution of a software module, a processor may load some instructions into a cache memory to increase access speed. One or more cache memory lines may then be loaded into a general register stack for execution by the processor. When the functions of a software module are mentioned below, it should be understood that such functions are implemented by the processor when instructions from the software module are executed.

[0174] In addition, any connection is properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio and microwave are included in the definition of medium. Disk and optical disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Optical disks, where magnetic disks generally reproduce data magnetically, and optical disks reproduce data optically with lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transitory computer-readable media (e.g., signals). Combinations of the above may also be considered examples of computer-readable media.

[0175] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include a computer-readable medium having stored thereon (and / or encoded thereon) instructions, the instructions being executable by one or more processors to perform the operations described herein, for example, for performing the operations described herein and in Figure 11-Figure 12 The operations shown in the instructions.

[0176] In addition, it should be understood that the modules and / or other appropriate units for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by the user terminal and / or base station (if applicable). For example, such a device can be coupled to a server to facilitate the transmission of components for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage component (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or a floppy disk, etc.), so that the user terminal and / or base station can obtain the various methods immediately after the storage component is coupled or provided to the device. In addition, any other suitable technology for providing the methods and techniques described herein to a device can be utilized.

[0177] It is to be understood that the claims are not limited to the precise configuration and components described above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above.

Claims

1. A method for wireless communication by a network entity, comprising: determining resources used to monitor a physical random access channel (PRACH) transmission sent from a user equipment (UE) as part of a random access channel (RACH) procedure; When receiving a PRACH repetition sent using the determined resources, performing receive beam scanning; using a result of the receive beam scanning to refine one or more beams and selecting a refined beam from the refined one or more beams; as well as The selected refined beam is used to at least one of receive a subsequent message from the UE as part of the RACH procedure or send a subsequent message to the UE as part of the RACH procedure.

2. The method according to claim 1, further comprising: When one or more conditions are met, PRACH repetitions are received from the UE using the determined resources.

3. The method according to claim 2, wherein: The one or more conditions are related to the reference signal received power RSRP measurement based on the synchronization signal block SSB.

4. The method of claim 3, further comprising configuring the UE to send PRACH repetitions using the determined resources if the SSB-based RSRP measurement is less than a threshold.

5. The method according to claim 4, wherein: Configuring the UE with the threshold includes: configuring the UE with the threshold via at least one of the following: Remaining Minimum System Information RMSI; or Some other system information SI.

6. The method of claim 1, further comprising signaling to the UE an indication of time resources for the PRACH repetition.

7. The method according to claim 6, wherein: The signaling notification includes at least one of the following: Remaining Minimum System Information RMSI; or Some other system information SI.

8. The method of claim 1, further comprising detecting the PRACH repetitions separately for each refined beam scan.

9. The method according to claim 1, further comprising: The PRACH repetitions are detected after soft combining received signals on different refined beams of the refined one or more beams.

10. The method according to claim 1, wherein: Selecting the refined beam from the refined one or more beams includes selecting the refined beam based on comparing reference signal received powers (RSRP) of different PRACH repetitions.

11. The method according to claim 1, wherein: The refined one or more beams are a subset of the synchronization signal block SSB beam set.

12. The method according to claim 1, wherein: The resources correspond to one or more RACH opportunities.

13. A method for wireless communication by a user equipment UE, comprising: determining a random access channel, RACH, opportunity associated with one or more synchronization signal block, SSB beams, for sending a physical random access channel, PRACH, transmission with repetition; as well as If one or more conditions are met, sending a PRACH repetition using resources corresponding to the determined RACH opportunity, The one or more conditions are related to SSB-based reference signal received power RSRP measurement, and The sending of the PRACH repetition includes: if the SSB-based RSRP measurement is less than a threshold, sending the PRACH repetition using resources corresponding to the determined RACH opportunity.

14. The method according to claim 13, wherein: The threshold is configured via at least one of: Remaining Minimum System Information RMSI; or Some other system information SI.

15. An apparatus for wireless communication, comprising: at least one processor; as well as 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: determining resources used to monitor a physical random access channel (PRACH) transmission sent from a user equipment (UE) as part of a random access channel (RACH) procedure; When receiving a PRACH repetition sent using the determined resource, performing receive beam scanning; using a result of the beam scanning to refine one or more beams and selecting a refined beam from the refined one or more beams; as well as The selected refined beam is used to at least one of receive a subsequent message from the UE as part of the RACH procedure or send a subsequent message to the UE as part of the RACH procedure.

16. The device according to claim 15, wherein: The memory also includes code executable by the at least one processor to cause the apparatus to receive PRACH repetitions from the UE using the determined resources when one or more conditions are met.

17. The device according to claim 16, wherein: The one or more conditions are related to the reference signal received power RSRP measurement based on the synchronization signal block SSB.

18. The device according to claim 17, wherein: The memory also includes code executable by the at least one processor to cause the apparatus to configure the UE to send PRACH repetitions using the determined resources if the SSB-based RSRP measurement is less than a threshold.

19. The device according to claim 18, wherein: The code executable by the at least one processor to cause the apparatus to configure the UE with the threshold value includes: code executable by the at least one processor to cause the apparatus to configure the UE with the threshold value via at least one of: Remaining Minimum System Information RMSI; or Some other system information SI.

20. The device according to claim 15, wherein: The memory further includes code executable by the at least one processor to cause the apparatus to signal to the UE an indication of a time resource for the PRACH repetition, wherein the code executable by the at least one processor to cause the apparatus to signal at least one of: Remaining Minimum System Information RMSI; or Some other system information SI.

21. The device according to claim 15, wherein: The memory also includes code executable by the at least one processor to cause the apparatus to separately detect the PRACH repetition for each refined beam scan.

22. The device according to claim 15, wherein: The memory also includes code executable by the at least one processor to cause the apparatus to detect a PRACH repetition after soft combining received signals on different ones of the refined one or more beams.

23. The device according to claim 15, wherein: The code capable of being executed by the at least one processor to cause the device to select a refined beam from the one or more refined beams includes: the code capable of being executed by the at least one processor to cause the device to select the refined beam based on comparing the reference signal received power RSRP of different PRACH repetitions.

24. The device according to claim 15, wherein: The refined one or more beams are a subset of the synchronization signal block SSB beam set.

25. The device according to claim 15, wherein: The resources correspond to one or more RACH opportunities.

26. An apparatus for wireless communication, comprising: means for determining resources used to monitor a physical random access channel, PRACH, transmission sent from a user equipment, UE, as part of a random access channel, RACH, procedure; means for performing receive beam scanning when receiving a PRACH repetition transmitted using the determined resources; means for refining one or more beams using a result of the beam scanning and selecting a refined beam from the refined one or more beams; as well as means for using the selected refined beam to at least one of: receiving a subsequent message from the UE as part of the RACH procedure; or A subsequent message is sent to the UE as part of the RACH procedure.

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