Patent Description:
These improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

<CIT> relates to executing multi-beam-based random access procedure in wireless communication. <CIT> relates to transmission beam indicating.

According to the present invention, there is provided a method for wireless communication as set out in claims <NUM> and <NUM> and an apparatus for wireless communication as set out in claim <NUM>. Other aspects of the invention can be found in the dependent claims.

It is to be noted, however, that the appended drawings illustrate only certain aspects of this disclosure and the description may admit to other equally effective aspects.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable mediums for beam refinement via physical random access channel (PRACH) repetition.

The following description provides examples of beam refinement via PRACH repetition in communication systems. Changes may be made in the function and arrangement of elements discussed. In addition, the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein.

A RAT may also be referred to as a radio technology, an air interface, etc. A frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs.

NR supports beamforming and beam direction may be dynamically configured.

As shown in <FIG>, the wireless communication network <NUM> may be in communication with a core network <NUM>. The core network <NUM> may in communication with one or more base station (BSs) 110a-z (each also individually referred to herein as BS <NUM> or collectively as BSs <NUM>) and/or user equipment (UE) 120a-y (each also individually referred to herein as UE <NUM> or collectively as UEs <NUM>) in the wireless communication network <NUM> via one or more interfaces.

According to certain aspects, the BSs <NUM> and UEs <NUM> may be configured for beam refinement via PRACH repetitions. As shown in <FIG>, the BS 110a includes a beam manager <NUM> that performs beam refinement based on PRACH repetitions, in accordance with aspects of the present disclosure. The UE 120a includes a PRACH repetition manager <NUM> that sends PRACH repetitions corresponding to a determined RACH occasion, in accordance with aspects of the present disclosure.

The BSs <NUM> communicate with UEs <NUM> in the wireless communication network <NUM>. Wireless communication network <NUM> may also include relay stations (e.g., relay station 110r), also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS 110a or a UE 120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE <NUM> or a BS <NUM>), or that relays transmissions for other UEs <NUM>, to facilitate communication between devices.

A network controller <NUM> may couple to a set of BSs <NUM> and provide coordination and control for these BSs (e.g., via a backhaul). In aspects, the network controller <NUM> may be in communication with a core network <NUM> (e.g., a <NUM> Core Network (5GC)), which provides various network functions such as Access and Mobility Management, Session Management, User Plane Function, Policy Control Function, Authentication Server Function, Unified Data Management, Application Function, Network Exposure Function, Network Repository Function, Network Slice Selection Function, etc..

For example, for RAN sharing, radio as a service (RaaS), and service specific ANC deployments, TRPs <NUM> may be connected to more than one ANC.

The logical architecture of distributed RAN <NUM> may support various backhauling and fronthauling solutions. This support may occur via and across different deployment types.

<FIG> illustrates example components of BS <NUM> and UE <NUM> (as depicted in <FIG>), which may be used to implement aspects of the present disclosure.

The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data may be for the 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. The 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).

The processor <NUM> may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. A transmit (TX) multiple-input multiple-output (MIMO) processor <NUM> may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) in transceivers 432a through 432t. Each modulator in transceivers 432a-432t may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Downlink signals from the modulators in transceivers 432a through 432t may be transmitted via the antennas 434a through 434t, respectively.

At the UE <NUM>, antennas 452a through 452r may receive downlink signals from the base station <NUM> and may provide received signals to demodulators (DEMODs) in transceivers 454a through 454r, respectively. Each demodulator in transceivers 454a-454r may condition (e.g., filter, amplify, down convert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector <NUM> may obtain received symbols from all demodulators in transceivers 454a through 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols.

At the BS <NUM>, uplink signals from the UE <NUM> may be received by the antennas <NUM>, processed by the modulators in transceivers 432a-432t, detected by a MIMO detector <NUM> if applicable, and further processed by a receive processor <NUM> to obtain decoded data and control information sent by the UE <NUM>.

The controllers/processors <NUM> and <NUM> may direct operations at the base station <NUM> and the UE <NUM>, respectively. The processor <NUM> and/or other processors and modules at the BS <NUM> may perform or direct execution of processes for techniques described herein.

Antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE 120a and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS 110a may be used to perform the various techniques and methods described herein. For example, as shown in <FIG>, the controller/processor <NUM> of the BS 110a has a beam manager <NUM> that performs beam refinement based on PRACH repetitions, according to aspects described herein. As shown in <FIG>, the controller/processor <NUM> of the UE 120a has a PRACH repetition manager <NUM> that sends PRACH repetitions corresponding to a determined RACH occasion, according to aspects described herein. Although shown at the controller/processor, other components of the UE 120a and BS 110a may be used to perform the operations described herein.

NR may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the downlink and on the uplink. OFDM and single-carrier frequency division multiplexing (SC-FDM) partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. Modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The minimum resource allocation, called a "resource block" (RB), may be <NUM> consecutive subcarriers.

Embodiments discussed herein may include a variety of spacing and timing deployments. For example, in LTE, the basic transmission time interval (TTI) or packet duration is the <NUM> subframe. A subframe contains a variable number of slots (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, slots) depending on the subcarrier spacing.

Each subframe may include a variable number of slots (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>,. Each slot may include a variable number of symbol periods (e.g., <NUM>, <NUM>, or <NUM> symbols) depending on the SCS. A sub-slot structure may refer to a transmit time interval having a duration less than a slot (e.g., <NUM>, <NUM>, or <NUM> symbols).

In NR, a synchronization signal (SS) block (SSB) is transmitted. In certain aspects, SSBs may be transmitted in a burst where each SSB in the burst corresponds to a different beam direction for UE-side beam management (e.g., including beam selection and/or beam refinement). The PSS may provide half-frame timing, and the SS may provide the CP length and frame timing. The PBCH carries some basic system information, such as downlink system bandwidth, timing information within radio frame, SS burst set periodicity, system frame number, etc. Further system information such as, remaining minimum system information (RMSI), system information blocks (SIBs), other system information (OSI) can be transmitted on a physical downlink shared channel (PDSCH) in certain subframes. The SSB can be transmitted up to sixty-four times, for example, with up to sixty-four different beam directions for mmWave. The multiple transmissions of the SSB are referred to as a SS burst set. SSBs in an SS burst set may be transmitted in the same frequency region, while SSBs in different SS bursts sets can be transmitted at different frequency regions.

A control resource set (CORESET) for an OFDMA system (e.g., a communications system transmitting PDCCH using OFDMA waveforms) may comprise one or more control resource (e.g., time and frequency resources) sets, configured for conveying PDCCH, within the system bandwidth. Within each CORESET, one or more search spaces (e.g., common search space (CSS), UE-specific search space (USS), etc.) may be defined for a given UE. Search spaces are generally areas or portions where a communication device (e.g., a UE) may look for control information.

According to 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 comprise a fixed number (e.g., twelve) tones in one symbol period (e.g., a symbol period of a slot), where one tone in one symbol period is referred to as a resource element (RE). A fixed number of REGs may be included in a control channel element (CCE). Sets of CCEs may be used to transmit new radio PDCCHs (NR-PDCCHs), with different numbers of CCEs in the sets used to transmit NR-PDCCHs using differing aggregation levels. Multiple sets of CCEs may be defined as search spaces for UEs, and thus a NodeB or other base station may transmit an NR-PDCCH to a UE by transmitting the NR-PDCCH in a set of CCEs that is defined as a decoding candidate within a search space for the UE, and the UE may receive the NR-PDCCH by searching in search spaces for the UE and decoding the NR-PDCCH transmitted by the NodeB.

Operating characteristics of a NodeB or other base station in an NR communications system may be dependent on a frequency range (FR) in which the system operates. A frequency range may comprise one or more operating bands (e.g., "n1" band, "n2" band, "n7" band, and "n41" band), and a communications system (e.g., one or more NodeBs 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" TS38. <NUM> (Release <NUM>), which is available from the 3GPP website.

As described above, a CORESET is a set of time and frequency domain resources. The CORESET can be configured for conveying PDCCH within system bandwidth. A UE may determine a CORESET and monitors the CORESET for control channels. During initial access, a UE may identify an initial CORESET (CORESET #<NUM>) configuration from a field (e.g., pdcchConfigSIB1) in a maser information block (MIB). This initial CORESET may then be used to configure the UE (e.g., with other CORESETs and/or bandwidth parts via dedicated (UE-specific) signaling. When the UE detects a control channel in the CORESET, the UE attempts to decode the control channel and communicates with the transmitting BS (e.g., the transmitting cell) according to the control data provided in the control channel (e.g., transmitted via the CORESET).

According to 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 can be in a synchronization signal and physical broadcast channel (SS/PBCH) block (e.g., in the PBCH of the SS/PBCH block) on a synchronization raster (sync raster). In some scenarios, the sync raster may correspond to an SSB. From the frequency of the sync raster, the UE may determine an operating band of the cell. Based on a cell's operation band, the UE may determine a minimum channel bandwidth and a subcarrier spacing (SCS) of the channel. The UE may then determine an index from the MIB (e.g., four bits in the MIB, conveying an index in a range <NUM>-<NUM>).

Given this index, the UE may look up or locate a CORESET configuration (this initial CORESET configured via the MIB is generally referred to as CORESET #<NUM>). This may be accomplished 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.

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

<FIG> shows an exemplary transmission resource mapping <NUM>, according to aspects of the present disclosure. In the exemplary mapping, a BS (e.g., BS 110a, shown in <FIG>) transmits an SS/PBCH block <NUM>. The SS/PBCH block includes a MIB conveying an index to a table that relates the time and frequency resources of the CORESET <NUM> to the time and frequency resources of the SS/PBCH block.

The BS may also transmit control signaling. In some scenarios, the BS may also transmit a PDCCH to a UE (e.g., UE <NUM>, shown in <FIG>) in the (time/frequency resources of the) CORESET. The PDCCH may schedule a PDSCH <NUM>. The BS then transmits the PDSCH to the UE. The UE may receive the MIB in the SS/PBCH block, determine the index, look up a CORESET configuration based on the index, and determine the CORESET from the CORESET configuration and the SS/PBCH block. The UE may then monitor the CORESET, decode the PDCCH in the CORESET, and receive the PDSCH that was allocated by the PDCCH.

Different CORESET configurations may have different parameters that define a corresponding CORESET. For example, each configuration may indicate a number of resource blocks (e.g., <NUM>, <NUM>, or <NUM>), a number of symbols (e.g., <NUM>-<NUM>), as well as an offset (e.g., <NUM>-<NUM> RBs) that indicates a location in frequency.

In many cases, it is important for a user equipment (UE) to know which assumptions it can make on a channel 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., physical downlink control channel (PDCCH) or 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 <NUM> new radio (NR), the concept of quasi co-location (QCL) and transmission configuration indicator (TCI) states is used to convey information about these assumptions.

QCL assumptions are generally defined in terms of channel properties. Per 3GPP TS <NUM>, "two antenna ports are said to be quasi-co-located if properties of the channel over which a symbol on one antenna port is conveyed can be inferred from the channel over which a symbol on the other antenna port is conveyed. " Different reference signals may be considered quasi co-located ("QCL'd") if a receiver (e.g., a UE) can apply channel properties determined by detecting a first reference signal to help detect a second reference signal. TCI states generally include configurations such as QCL-relationships, for example, between the DL RSs in one CSI reference signal (CSI-RS) set and the PDSCH demodulation reference signals (DMRS) ports.

In some cases, a UE may be configured with up to M TCI-States. Configuration of the M TCI-States can come about via higher layer signalling, while a UE may be signalled to decode PDSCH according to a detected PDCCH with DCI indicating one of the TCI states. Each configured TCI state may include one RS set TCI-RS-SetConfig that indicates different QCL assumptions between certain source and target signals.

<FIG> illustrate examples of the association of DL reference signals with corresponding QCL types that may be indicated by a TCI-RS-SetConfig.

In the examples of <FIG>, a source reference signal (RS) is indicated in the top block and is associated with a target signal indicated in the bottom block. In this context, a target signal generally refers to a signal for which channel properties may be inferred by measuring those channel properties for an associated source signal. As noted above, a UE may use the source RS to determine various channel parameters, depending on the associated QCL type, and use those various channel properties (determined based on the source RS) to process the target signal. A target RS does not necessarily need to be PDSCH's DMRS, rather it can be any other RS: physical uplink shared channel (PUSCH) DMRS, CSI-RS, tracking reference signal (TRS), and sounding reference signal (SRS).

As illustrated, each TCI-RS-SetConfig contains parameters. These parameters can, for example, configure quasi co-location relationship(s) between reference signals in the RS set and the DM-RS port group of the PDSCH. The RS set contains a reference to either one or two DL RSs and an associated quasi co-location type (QCL-Type) for each one configured by the higher layer parameter QCL-Type.

As illustrated in <FIG>, for the case of two DL RSs, the QCL types can take on a variety of arrangements. For example, QCL types may not be the same, regardless of whether the references are to the same DL RS or different DL RSs. In the illustrated example, SSB is associated with Type C QCL for P-TRS, while CSI-RS for beam management (CSIRS-BM) is associated with Type D QCL.

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

Spatial QCL assumptions (QCL-TypeD) may be used to help a UE to select an analog Rx beam (e.g., during beam management procedures). For example, an SSB resource indicator may indicate a same beam for a previous reference signal should be used for a subsequent transmission.

An initial CORESET (e.g., CORESET ID <NUM> or simply CORESET#<NUM>) in NR may be identified during initial access by a UE (e.g., via a field in the MIB). A ControlResourceSet information element (CORESET IE) sent via radio resource control (RRC) signaling may convey information regarding a CORESET configured for a UE. The CORESET IE generally includes a CORESET ID, an indication of frequency domain resources (e.g., number of RBs) assigned to the CORESET, contiguous time duration of the CORESET in a number of symbols, and Transmission Configuration Indicator (TCI) states.

As noted above, a subset of the TCI states provide quasi co-location (QCL) relationships between DL RS(s) in one RS set (e.g., TCI-Set) and PDCCH demodulation RS (DMRS) ports. A particular TCI state for a given UE (e.g., for unicast PDCCH) may be conveyed to the UE by the Medium Access Control (MAC) Control Element (MAC-CE). The particular TCI state is generally selected from the set of TCI states conveyed by the CORESET IE, with the initial CORESET (CORESET#<NUM>) generally configured via MIB.

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 a search space configured for a CORESET by a search space ID. In an aspect, the search space ID associated with CORESET # <NUM> is Search Space ID #<NUM>. The search space is generally configured via PBCH (MIB).

A random-access channel (RACH) is so named because it refers to a wireless channel (medium) that may be shared by multiple user equipments (UEs) and used by the UEs to (randomly) access the network for communications. For example, the RACH may be used for call setup and to access the network for data transmissions. In some cases, RACH may be used for initial access to a network when the UE switches from a radio resource control (RRC) connected idle mode to active mode, or when handing over in RRC connected mode. Moreover, RACH may be used for downlink (DL) and/or uplink (UL) data arrival when the UE is in RRC idle or RRC inactive modes, and when reestablishing a connection with the network.

Typically, a UE monitors synchronization signal block (SSB) transmissions which are sent (by a gNB using different beams) and are associated with a finite set of time/frequency resources defining RACH occasions (ROs). As will be described in greater detail below, upon detecting an SSB, the UE may select an RO associated with that SSB for a msgA transmission. The finite set of ROs may help reduce monitoring overhead (blind decodes) by a base station. In other words, by associating a finite set of ROs with SSB transmissions, a gNB knows when, where, and in what direction to "listen" for RACH transmissions from a UE.

<FIG> is a timing (or "call-flow") diagram <NUM> illustrating an example four step RACH procedure, in accordance with certain aspects of the present disclosure. A first message (e.g., MSG1) may be sent from the UE <NUM> to BS <NUM> on the physical random access channel (PRACH). In this case, MSG1 may only include a RACH preamble. BS <NUM> may respond with a second message (e.g.,MSG2, a random access response (RAR) message), which may include the identifier (ID) of the RACH preamble, a timing advance (TA), an uplink grant, cell radio network temporary identifier (C-RNTI), and a back off indicator. The RAR message may include a physical downlink control channel (PDCCH) communication including control information for a following communication on the physical downlink shared channel (PDSCH), as illustrated. In response to the RAR message, a third message (e.g., MSG3) is transmitted from the UE <NUM> to BS <NUM> on the PUSCH. The third message may include one or more of a RRC connection request, a tracking area update request, a system information request, a positioning fix or positioning signal request, or a scheduling request. The BS <NUM> then responds with a fourth message (MSG4) which may include a contention resolution message. In contention-free random access, the preamble is assigned to the UE and last two messages are skipped.

As noted above, the UE sends a preamble on a RACH occasion associated with a prior SSB transmission by the gNB. RACH procedures used for different purposes including initial access, synchronization, uplink scheduling request, beam-recovery, and the like. A RACH configuration of a cell typically specifies a number of SSB time indices per RACH time/frequency occasions (which could be one, less than one or greater than one).

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

A first enhanced message (msgA) may be sent from a UE to a BS. In certain aspects, msgA includes some or all the information from the first message (e.g., MSG1) and the third message (e.g., MSG3) from the four step RACH procedure, 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 certain aspects, msgA includes a RACH preamble for random access and a payload. The msgA payload, for example, may include the UE-ID and other signaling information (e.g., buffer status report (BSR)) or scheduling request (SR). The BS may respond with a RAR message (e.g., msgB), which may effectively combine the second message (e.g., MSG2) and the fourth message (e.g., MSG4) described above. For example, msgB may include the ID of the RACH preamble, a timing advance (TA), a back off indicator, a contention resolution message, UL/DL grant, and transmit power control (TPC) commands.

The techniques described herein may utilize both <NUM>-step and <NUM>-step RACH procedures and mechanisms.

Certain aspects of the present disclosure provide techniques for network-side beam refinement based on physical random access channel (PRACH) repetition. The beam refinement, resulting from the beam sweep, may be used for reception of a third message (e.g., MSG3) and/or transmission of a second message (e.g., MSG2) in a four-step random access channel (RACH) procedure.

These techniques may improve system performance as MSG2 and MSG3 are bottlenecks for coverage of millimetre-wave <NUM>. In some cases, RACH procedures may create a bottleneck because there are no narrowbands available and thus the RACH procedures relies on wide broadcast beams based on synchronization signal block (SSB) beams, resulting in reduced beam gain. With reduced beam gain, coverage issues occur. One way to address coverage issues is to introduce coverage enhancement through repetition and/or beam refinement.

<FIG> is a flow diagram illustrating example operations <NUM> for wireless communication by a network entity. For example, operations <NUM> may be performed, for example, by a base station (BS) <NUM> (e.g., a gNB).

Operations <NUM> begin, at <NUM>, with the network entity determining resources to monitor for a PRACH transmission sent from a user equipment (UE) as part of a random access channel (RACH) procedure.

In some aspects, at <NUM>, the network entity may configure the UE to send PRACH repetitions using the determined resources if the SSB-based reference signal received power (RSRP) measurement is less than a threshold value.

In some aspects, at <NUM>, the network entity may signal the UE an indication of time resources for the PRACH repetitions.

In some aspects, at <NUM>, the network entity may detect the PRACH repetitions separately for each refined beam sweep.

In some aspects, at <NUM>, the network entity may detect the PRACH repetitions after soft combining of received signals on different refined beams of the refined one or more beams.

In some aspects, at <NUM>, the network entity may receive, from the UE, PRACH repetitions using the determined resources when one or more conditions are met.

At <NUM>, the network entity performs receive beam sweeping when receiving PRACH repetitions sent using the determined resources.

At <NUM>, the network entity uses results of the beam sweeping to refine one or more beams and to select a refined beam from the refined one or more beams.

At <NUM>, the network entity uses the selected refined beam for at least of receiving a subsequent message from the UE as part of the RACH procedure or sending a subsequent message to the UE as part of the RACH procedure.

<FIG> is a flow diagram illustrating example operations <NUM> for wireless communication by a UE, and may be considered complementary to operations <NUM> of <FIG>. The operations <NUM> may be performed, for example, by a UE <NUM> in conjunction with a BS <NUM> performing operations <NUM> of <FIG>.

Operations <NUM> begin, at <NUM>, with the UE determining a RACH occasion associated with one or more synchronization signal blocks (SSBs) beams for sending a PRACH transmission with repetition.

In some aspects, at <NUM>, the UE may receive signaling indicating time resources for the PRACH repetitions.

At <NUM>, the UE sends PRACH repetitions using resources corresponding to the determined RACH occasion if one or more conditions are met.

PRACH repetition and receive-beam sweep and associated beam refinement for MSG3 and/or MSG2 in accordance with operations <NUM> and <NUM> of <FIG> and <FIG> may be understood with reference to the example flow diagram of <FIG>.

As illustrated in <FIG>, a gNB configures a UE for PRACH repetitions. In some cases, the configuration may indicate resources for the PRACH repetition and/or may indicate one or more conditions to trigger the UE to send PRACH repetitions (e.g., conditions indicate beam refinement may be beneficial).

As illustrated, the UE detects conditions to trigger PRACH repetitions, and thus sends PRACH repetitions to the gNB. The gNB performs receive beam sweeps for the PRACH repetitions, and selects a refined beam. At a later time, the network entity uses the refined beam to transmit MSG2 to the UE and/or receive MSG3 from the UE.

Certain aspects of the present disclosure are direct to an implementation of a combined control element (CE) for MSG1, MSG2, and MSG3 by repeating PRACH repetitions and/or receive beam sweeping. PRACH repetitions and/or receive-beam sweeps, especially of MSG1, may be used for beam refinement of MSG2 and/or MSG3.

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

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

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

The communications device <NUM> includes a processing system <NUM> coupled to a transceiver <NUM> (e.g., a transmitter and/or a receiver).

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer-executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, or other operations for performing the various techniques discussed herein for beam refinement via PRACH repetitions. In certain aspects, computer-readable medium/memory <NUM> stores code <NUM> for determining resources to monitor for a physical random access channel (PRACH) transmission sent from a user equipment (UE) as part of a random access channel (RACH) procedure; code <NUM> for performing receive beam sweeping when receiving PRACH repetitions sent using the determined resources; circuitry <NUM> for using results of the receive beam sweeping to refine one or more beams and to select a refined beam of the refined one or more beams; and circuitry <NUM> for using the selected refined beam for at least one of receiving a subsequent message from the UE as part of the RACH procedure or sending a subsequent message to the UE as part of the RACH procedure. In certain aspects, computer readable medium/memory <NUM> may store code <NUM> for receiving, from the UE, PRACH repetitions using the determined resources when one or more conditions are met. In certain aspects, computer readable medium/memory <NUM> may store code <NUM> for configuring the UE to send PRACH repetitions using the determined resources if the SSB-based RSRP measurement is less than a threshold value. In certain aspects, computer readable medium/memory <NUM> may store code <NUM> for signaling the UE an indication of time resources for the PRACH repetitions. In certain aspects, computer readable medium/memory <NUM> may store code <NUM> for detecting the PRACH repetitions separately for each refined beam sweep. In certain aspects, computer readable medium/memory <NUM> may store code <NUM> for detecting the PRACH repetitions after soft combining of received signals on different refined beams of the refined one or more beams. In certain aspects, the processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for determining resources to monitor for a PRACH transmission sent from a UE as part of a RACH procedure; circuitry <NUM> for performing receive beam sweeping when receiving PRACH repetitions sent using the determined resources; circuitry <NUM> for using results of the receive beam sweeping to refine one or more beams and to select a refined beam of the refined one or more beams; and circuitry <NUM> for using the selected refined beam for at least one of receiving a subsequent message from the UE as part of the RACH procedure or sending a subsequent message to the UE as part of the RACH procedure. In certain aspects, processor <NUM> may include circuitry <NUM> for receiving, from the UE, PRACH repetitions using the determined resources when one or more conditions are met. In certain aspects, processor <NUM> may include circuitry <NUM> for configuring the UE to send PRACH repetitions using the determined resources if the SSB-based RSRP measurement is less than a threshold value. In certain aspects, processor <NUM> may include circuitry <NUM> for signaling the UE an indication of time resources for the PRACH repetitions. In certain aspects, processor <NUM> may include circuitry <NUM> for detecting the PRACH repetitions separately for each refined beam sweep. In certain aspects, processor <NUM> may include circuitry <NUM> for detecting the PRACH repetitions after soft combining of received signals on different refined beams of the refined one or more beams.

For example, means for transmitting (or means for outputting for transmission) may include a transmitter and/or an antenna(s) <NUM> or the BS 110a illustrated in <FIG> and/or circuitry <NUM> of the communication device <NUM> in <FIG>. Means for receiving (or means for obtaining) may include a receiver and/or an antenna(s) <NUM> of the BS 110a illustrated in <FIG> and/or circuitry <NUM> of the communication device <NUM> in <FIG>. Means for communicating may include a transmitter, a receiver or both. Means for generating, means for performing, means for determining, means for taking action, means for determining, means for coordinating may include a processing system, which may include one or more processors, such as the transmit processor <NUM>, the TX MIMO processor <NUM>, the receive processor <NUM>, and/or the controller/processor <NUM> of the BS 110a illustrated in <FIG> and/or the processing system <NUM> of the communication device <NUM> in <FIG>.

The processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, the computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer-executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations illustrated in <FIG>, or other operations for performing the various techniques discussed herein for beam refinement via PRACH repetitions. In certain aspects, computer-readable medium/memory <NUM> stores code <NUM> for determining a RACH occasion associated with one or more SSBs beams for sending a PRACH transmission with repetition; and code <NUM> for sending PRACH repetitions using resources corresponding to the determined RACH occasion if one or more conditions are met. In certain aspects, computer-readable medium/memory <NUM> may store code <NUM> for receiving signaling indicating time resources for the PRACH repetitions. In certain aspects, the processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for determining a RACH occasion associated with one or more SSBs beams for sending a PRACH transmission with repetition; circuitry <NUM> for sending PRACH repetitions using resources corresponding to the determined RACH occasion if one or more conditions are met. In certain aspects, processor <NUM> may include circuitry <NUM> for receiving signaling indicating time resources for the PRACH repetitions.

For example, means for transmitting (or means for outputting for transmission) may include the transmitter unit <NUM> and/or antenna(s) <NUM> of the UE 120a illustrated in <FIG> and/or circuitry <NUM> of the communication device <NUM> in <FIG>. Means for receiving (or means for obtaining) may include a receiver and/or antenna(s) <NUM> of the UE 120a illustrated in <FIG>. Means for communicating may include a transmitter, a receiver or both. Means for generating, means for performing, means for determining, means for taking action, means for determining, means for coordinating may include a processing system, which may include one or more processors, such as the receive processor <NUM>, the transmit processor <NUM>, the TX MIMO processor <NUM>, and/or the controller/processor <NUM> of the UE 120a illustrated in <FIG> and/or the processing system <NUM> of the communication device <NUM> in <FIG>.

The techniques described herein may be used for various wireless communication technologies, such as NR (e.g., <NUM> 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.

cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project <NUM>" (3GPP2 NR is an emerging wireless communications technology under development.

In 3GPP, the term "cell" can refer to a coverage area of a NodeB (NB) and/or a NodeB subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term "cell" and next generation NodeB (gNB), new radio base station (NR BS), <NUM> NB, access point (AP), or transmission reception point (TRP) may be used interchangeably.

A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE), a cellular phone, a 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 equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, gaming device, reality augmentation device (augmented reality (AR), extended reality (XR), or virtual reality (VR)), or any other suitable device that is configured to communicate via a wireless or wired medium.

That is, for scheduled communication, subordinate entities can utilize resources allocated by the scheduling entity.

The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified.

Reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more.

The means may include various hardware and/or software component(s) and/or module(s), including, but not limited to a circuit, a digital signal processor (DSP), an application specific integrated circuit (ASIC), or a processor (e.g., a general purpose or specifically programmed processor).

The various illustrative logical blocks, modules and circuits described in connection 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.

Combinations of the above can also be considered as examples of computer-readable media.

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