Random access channel transmission process in higher frequency band

Abstract

Aspects of the present disclosure generally relate to wireless communications. In some aspects, based at least in part on the subcarrier spacing in a cell associated with a base station, the base station may send initial timing advance information in a msg2 communication of a four-step random access channel process, and a user equipment (UE) may receive the initial timing advance information in a msg2 communication of a four-step random access channel process. The UE may send a msg3 communication, and the base station may receive a msg3 communication, wherein the msg3 communication uses an initial timing advance based at least in part on the initial timing advance information. Based at least in part on the base station detecting the msg3 communication, the base station may send updated timing advance information, and the UE may receive updated timing advance information, wherein the updated timing advance information resolves the timing advance wraparound between the UE and the base station. Many other aspects are provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Patent Application No. 62 / 980,663, filed on February 24, 2020, entitled “RANDOM ACCESS CHANNEL TRANSMISSION PROCEDURES IN HIGHER BANDS,” and U.S. Patent Application No. 17 / 248,334, filed on January 20, 2021, entitled “RANDOM ACCESS CHANNEL TRANSMISSION PROCEDURES IN HIGHER BANDS,” which are hereby expressly incorporated herein by reference. Technical Field

[0003] Aspects of the present disclosure relate generally to wireless communications and techniques and apparatus for random access channel (RACH) transmission procedures in higher frequency bands. Background Art

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

[0005] A wireless network may include multiple base stations (BSs) that can support communications for multiple user equipments (UEs). The UE may communicate with the BS via a downlink and an uplink. The downlink (or forward link) refers to a communication link from the BS to the UE, and the uplink (or reverse link) refers to a communication link from the UE to the BS. As will be described in more detail herein, the BS may be referred to as a Node B, gNB, access point (AP), radio head, transmit receive point (TRP), new air interface (NR) BS, 5G Node B, etc.

[0006] The above-mentioned multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user devices to communicate at the city, country, region and even global level. NR (also known as 5G) is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and using orthogonal frequency division multiplexing (OFDM) (CP-OFDM) with cyclic prefix (CP) on the downlink (DL), using CP-OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), and supporting beamforming, multiple-input multiple-output (MIMO) antenna technology and carrier aggregation to better integrate with other open standards. As the demand for mobile broadband access continues to grow, further improvements in LTE, NR and other wireless access technologies remain beneficial. Summary of the invention

[0007] In some aspects, a method of wireless communication performed by a user equipment (UE) may include: receiving initial timing advance information from a base station in a msg2 communication of a four-step random access channel (RACH) process based at least in part on a subcarrier spacing in a cell associated with the base station; sending a msg3 communication to the base station using the initial timing advance, wherein the initial timing advance is at least in part based on the initial timing advance information; and receiving updated timing advance information from the base station based at least in part on the base station detecting the msg3 communication, wherein the updated timing advance information resolves a timing advance wrap-around between the UE and the base station.

[0008] In some aspects, a method of wireless communication performed by a base station may include: sending initial timing advance information to a UE in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the base station; receiving a msg3 communication from the UE using the initial timing advance, wherein the initial timing advance is based at least in part on the initial timing advance information; and sending updated timing advance information to the UE based at least in part on the base station detecting the msg3 communication, wherein the updated timing advance information resolves a timing advance wraparound between the UE and the base station.

[0009] In some aspects, a UE for wireless communication may include a memory and one or more processors operably coupled to the memory. The memory and the one or more processors may be configured to: receive initial timing advance information from a base station in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the base station; send a msg3 communication to the base station using the initial timing advance, the initial timing advance based at least in part on the initial timing advance information; and receive updated timing advance information from the base station based at least in part on the base station detecting the msg3 communication, the updated timing advance information resolving a timing advance wrap between the UE and the base station.

[0010] In some aspects, a base station for wireless communication may include a memory and one or more processors operably coupled to the memory. The memory and the one or more processors may be configured to: send initial timing advance information to a UE in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the base station; receive a msg3 communication from the UE using the initial timing advance, the initial timing advance based at least in part on the initial timing advance information; and send updated timing advance information to the UE based at least in part on the base station detecting the msg3 communication, the updated timing advance information resolving a timing advance wrap between the UE and the base station.

[0011] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of a UE, the one or more instructions may cause the one or more processors to: receive initial timing advance information from a base station in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the base station; send a msg3 communication to the base station using the initial timing advance, the initial timing advance being based at least in part on the initial timing advance information; and receive updated timing advance information from the base station based at least in part on the base station detecting the msg3 communication, the updated timing advance information resolving a timing advance wrap between the UE and the base station.

[0012] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of a base station, the one or more instructions may cause the one or more processors to: send initial timing advance information to a UE in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the base station; receive a msg3 communication from the UE using an initial timing advance, the initial timing advance based at least in part on the initial timing advance information; and send updated timing advance information to the UE based at least in part on the base station detecting the msg3 communication, the updated timing advance information resolving a timing advance wrap between the UE and the base station.

[0013] In some aspects, an apparatus for wireless communication may include: a component for receiving initial timing advance information from a base station in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the base station; a component for sending a msg3 communication to the base station using the initial timing advance, wherein the initial timing advance is based at least in part on the initial timing advance information; and a component for receiving updated timing advance information from the base station based at least in part on the base station detecting the msg3 communication, wherein the updated timing advance information resolves a timing advance wrap between the apparatus and the base station.

[0014] In some aspects, an apparatus for wireless communication may include: a component for sending initial timing advance information to a UE in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the apparatus; a component for receiving a msg3 communication using an initial timing advance from the UE, wherein the initial timing advance is based at least in part on the initial timing advance information; and a component for sending updated timing advance information to the UE based at least in part on the apparatus detecting the msg3 communication, wherein the updated timing advance information resolves a timing advance wraparound between the UE and the apparatus.

[0015] Aspects generally include methods, apparatuses, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and / or processing systems as substantially described herein with reference to and illustrated by the accompanying drawings and description.

[0016] The features and technical advantages of the examples according to the present disclosure have been outlined quite broadly above so that the following detailed description may be better understood. Additional features and advantages will be described hereinafter. The disclosed concepts and specific examples may be easily used as a basis for modifying or designing other structures for achieving the same purpose of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, their organization and methods of operation, and related advantages will be better understood from the following description when considered in conjunction with the accompanying drawings. Each of the accompanying drawings is provided for the purpose of illustration and description and not as a definition of limitations to the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to be able to understand the above-mentioned features of the present disclosure in detail, a more specific description briefly summarized above may be made by reference to various aspects, some of which are shown in the accompanying drawings. However, it should be noted that the drawings only show certain typical aspects of the present disclosure and should not be considered to limit its scope, as the description may admit of other equally valid aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0018] Figure 1 is a diagram illustrating an example of a wireless network according to the present disclosure.

[0019] Figure 2 is a diagram illustrating an example of a base station communicating with a UE in a wireless network according to the present disclosure.

[0020] Figure 3 is a diagram illustrating an example of a two-step random access channel (RACH) procedure according to the present disclosure.

[0021] Figure 4 is a diagram illustrating an example of a four-step RACH procedure according to the present disclosure.

[0022] Figure 5 is a diagram illustrating one or more examples of physical RACH (PRACH) preamble formats that may be used in a two-step RACH procedure or a four-step RACH procedure according to the present disclosure.

[0023] Figures 6 to 9 as well as FIG. 10A to FIG. 10B is a diagram illustrating one or more examples of a RACH transmission procedure in a higher frequency band according to the present disclosure.

[0024] Fig.11 is a diagram illustrating an example process performed, for example, by a UE according to the present disclosure.

[0025] Fig.12 is a diagram illustrating an example process performed, for example, by a base station according to the present disclosure. DETAILED DESCRIPTION

[0026] Various aspects of the present disclosure are described more fully below with reference to the accompanying drawings. However, the present disclosure can be embodied in many different forms and should not be construed as being limited to any specific structure or function presented throughout the present disclosure. On the contrary, these aspects are provided so that the present disclosure will be thorough and complete, and the scope of the present disclosure will be fully conveyed to those skilled in the art. Based on the teachings herein, it should be understood by those skilled in the art that the scope of the present disclosure is intended to cover any aspect of the present disclosure disclosed herein, whether implemented independently of any other aspect of the present disclosure or implemented in combination with any other aspect of the present disclosure. For example, any number of aspects set forth herein can be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such a device or method: the device or method is practiced using other structures, functions, or structures and functions outside or outside the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the present disclosure disclosed herein can be embodied by one or more elements of the claims.

[0027] Several aspects of telecommunication systems will now be presented with reference to various devices and techniques. These devices and techniques will be described in the detailed description below and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using hardware, software, or a combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and design constraints imposed on the overall system.

[0028] It should be noted that although various aspects may be described herein using terminology generally associated with 5G or NR radio access technologies (RATs), various aspects of the present disclosure may be applied to other RATs, such as 3G RATs, 4G RATs, and / or RATs beyond 5G (e.g., 6G).

[0029] Figure 1 is a schematic diagram showing an example of a wireless network 100 according to the present disclosure. In other examples, the wireless network 100 may be or may include elements of a 5G (NR) network and / or an LTE network. The wireless network 100 may include a plurality of base stations 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A base station (BS) is an entity that communicates with a user equipment (UE) and may also be referred to as an NR BS, Node B, gNB, 5G Node B (NB), access point, transmit receive point (TRP), etc. Each BS may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​a BS and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0030] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs through service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs through service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown, BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "nodeB", "5G NB", and "cell" may be used interchangeably herein.

[0031] In some aspects, the cells are not necessarily stationary, and the geographic area of ​​the cells may move depending on the location of the mobile BS. In some aspects, the BSs may be interconnected to each other and / or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces (such as direct physical connections or virtual networks) using any suitable transport network.

[0032] The wireless network 100 may also include a relay station. A relay station is an entity that can receive data transmissions from an upstream station (e.g., a BS or a UE) and send data transmissions to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the illustrated example, relay BS 110d may communicate with macro BS 110a and UE 120d to facilitate communication between BS 110a and UE 120d. A relay BS may also be referred to as a relay station, relay base station, relay, or the like.

[0033] The wireless network 100 may be a heterogeneous network including different types of BSs, such as a macro BS, a pico BS, a femto BS, a relay BS, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 watts to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmit power level (e.g., 0.1 watt to 2 watts).

[0034] A network controller 130 may be coupled to a set of BSs and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with each other directly or indirectly via a wireless or wired backhaul.

[0035] UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. UEs may also be referred to as access terminals, terminals, mobile stations, subscriber units, stations, etc. UEs may be cellular phones (e.g., smart phones), personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, laptop computers, cordless phones, wireless local loop (WLL) stations, tablet computers, cameras, gaming devices, netbooks, smartbooks, ultrabooks, medical devices or equipment, biometric sensors / devices, wearable devices (smart watches, smart clothing, smart glasses, smart wristbands, smart jewelry (e.g., smart rings, smart bracelets)), entertainment devices (e.g., music or video devices or satellite radios), vehicle components or sensors, smart meters / sensors, industrial manufacturing equipment, global positioning system devices, or any other suitable device configured to communicate via wireless or wired media.

[0036] Some UEs may be considered as machine type communication (MTC) or evolved or enhanced machine type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors and / or location tags, which may communicate with a base station, another device (e.g., a remote device), or some other entity. For example, a wireless node may provide a connection to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link, or provide a connection to a network. Some UEs may be considered as Internet of Things (IoT) devices, and / or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered as customer premises equipment (CPE). UE 120 may be included in a housing that houses components (e.g., processor components and / or memory components) of UE 120. In some aspects, the processor component and the memory component may be connected together. For example, a processor component (e.g., one or more processors) and a memory component (e.g., a memory) may be operably connected, communicatively connected, electronically connected, and / or electrically connected.

[0037] Generally, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific RAT and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, frequency channel, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0038] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly (e.g., without using base station 110 as an intermediary to communicate with each other) using one or more sidelink channels. For example, UE 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocol (e.g., which may include vehicle-to-vehicle (V2V) protocol or vehicle-to-infrastructure (V2I) protocol) and / or mesh network. In this case, UE 120 may perform scheduling operations, resource selection operations, and / or other operations performed by base station 110 as described elsewhere herein.

[0039] Devices of the wireless network 100 may communicate using an electromagnetic spectrum that may be subdivided into various categories, frequency bands, and / or channels based at least in part on frequency or wavelength. For example, in other examples, devices of the wireless network 100 may communicate using an operating frequency band having a first frequency range (FR1) from 410 MHz to 7.125 GHz, may communicate using an operating frequency band having a second frequency range (FR2) from 24.25 GHz to 52.6 GHz, may communicate using an operating frequency band having a third frequency range (FR3) from 7.125 GHz to 24.25 GHz, may communicate using an operating frequency band having a fourth frequency range (FR4) from 52.6 GHz to 114.25 GHz, and / or may communicate using an operating frequency band having a fifth frequency range (FR5), the fifth frequency range may include frequencies above 114.25 GHz (e.g., sub-terahertz). Note that FR3 is between FR1 and FR2, and FR4 and FR5 are above FR2. Frequencies between FR1 and FR2 (e.g., in FR3) are sometimes referred to as mid-band frequencies or "sub-centimeter wave" bands. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as a "sub-6 GHz" band. Similarly, FR2, FR4, etc. are often referred to as "millimeter wave" bands, although they are different from the extremely high frequency (EHF) band (30 GHz to 300 GHz) identified as a "millimeter wave" band by the International Telecommunication Union (ITU). Therefore, unless otherwise stated, it should be understood that the term "sub-6 GHz", etc., if used herein, can broadly represent frequencies less than 6 GHz, frequencies within FR1, mid-band frequencies (e.g., greater than 7.125 GHz), etc. Similarly, unless otherwise stated, it should be understood that the term "millimeter wave", etc., if used herein, can broadly represent frequencies within the EHF band, frequencies within FR2, FR4 and / or FR5, mid-band frequencies (e.g., less than 24.25 GHz), etc. Furthermore, it is contemplated that the frequencies included in FR1, FR2, FR3, FR4, FR5, etc. may be modified and the techniques described herein applicable to those modified frequency ranges.

[0040] As shown above, provide Figure 1 As an example. Other examples may be related to Figure 1 Different than described.

[0041] Figure 2 is a diagram illustrating an example 200 of a base station 110 communicating with a UE 120 in a wireless network 100 according to the present disclosure. The base station 110 may be equipped with T antennas 234a through 234t, and the UE 120 may be equipped with R antennas 252a through 252r, where in general T≥1 and R≥1.

[0042] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS selected for the UE, and provide data symbols for all UEs. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, and / or upper layer signaling), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS) or demodulation reference signals (DMRS)) and synchronization signals (e.g., primary synchronization signals (PSS) or secondary synchronization signals (SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, if applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process a corresponding output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a to 232t may be transmitted via T antennas 234a to 234t, respectively.

[0043] At the UE 120, antennas 252a to 252r may receive downlink signals from the base station 110 and / or other base stations, and may provide received signals to demodulators (DEMODs) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM) to obtain received symbols. The MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. The receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE 120 to the data sink 260, and provide decoded control information and system information to the controller / processor 280. The term "controller / processor" may refer to one or more controllers, one or more processors, or a combination thereof. In other examples, the channel processor can determine a reference signal received power (RSRP) parameter, a received signal strength indicator (RSSI) parameter, a reference signal received quality (RSRQ) parameter, and / or a channel quality indicator (CQI) parameter. In some aspects, one or more components of UE 120 can be included in housing 284.

[0044] The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292. The network controller 130 may include, for example, one or more devices in a core network. The network controller 130 may communicate with the base station 110 via the communication unit 294.

[0045] In other examples, antennas (e.g., antennas 234a to 234t and / or antennas 252a to 252r) may include or may be included in one or more antenna panels, antenna groups, a group of antenna elements, and / or antenna arrays, etc. The antenna panel, antenna group, a group of antenna elements, and / or antenna array may include one or more antenna elements. The antenna panel, antenna group, a group of antenna elements, and / or antenna array may include a group of coplanar antenna elements and / or a group of non-coplanar antenna elements. The antenna panel, antenna group, a group of antenna elements, and / or antenna array may include antenna elements within a single housing and / or antenna elements within multiple housings. The antenna panel, antenna group, a group of antenna elements, and / or antenna array may include antenna elements connected to one or more transmitting components and / or receiving components (e.g., Figure 2 One or more antenna elements of one or more components).

[0046] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports including RSRP, RSSI, RSRQ, and / or CQI) from a controller / processor 280. The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 (if applicable), further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to the base station 110. In some aspects, the modulator and demodulator (e.g., MOD / DEMOD 254) of the UE 120 may be included in a modem of the UE 120. In some aspects, the UE 120 includes a transceiver. The transceiver may include any combination of antenna 252, modulator and / or demodulator 254, MIMO detector 256, receive processor 258, transmit processor 264, and / or TX MIMO processor 266. The transceiver may be used by a processor (e.g., controller / processor 280) and memory 282 to perform aspects of any of the methods described herein, for example, as described with reference to Figures 6 to 9 and / or FIG. 10A to FIG. 10B As described.

[0047] At the base station 110, uplink signals from the UE 120 and other UEs may be received by the antenna 234, processed by the demodulator 232, detected by the MIMO detector 236 (if applicable), and further processed by the receive processor 238 to obtain decoded data and control information sent by the UE 120. The receive processor 238 may provide the decoded data to the data sink 239 and the decoded control information to the controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The base station 110 may include a scheduler 246 for scheduling the UE 120 for downlink communication and / or uplink communication. In some aspects, the modulator and demodulator (e.g., MOD / DEMOD 232) of the base station 110 may be included in a modem of the base station 110. In some aspects, the base station 110 includes a transceiver. The transceiver may include any combination of antenna(s) 234, modulators and / or demodulators 232, MIMO detectors 236, receive processors 238, transmit processors 220, and / or TX MIMO processors 230. The transceiver may be adapted by a processor (e.g., controller / processor 240) and memory 242 to perform aspects of any of the methods described herein, for example, as described with reference to Figures 6 to 9 and / or FIG. 10A to FIG. 10B As described.

[0048] As described in more detail elsewhere herein, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component(s) of the base station 110 may perform one or more techniques associated with a random access channel (RACH) transmission procedure in a higher frequency band. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component(s) may perform or direct e.g. Fig.11 Process 1100, Fig.12 The operations of process 1200 and / or other processes described herein may be performed. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and / or program code) for wireless communication. For example, when one or more instructions are executed (e.g., directly or after compilation, conversion and / or interpretation) by one or more processors of base station 110 and / or UE 120, it may cause one or more processors, UE 120 and / or base station 110 to perform or direct, for example, Fig.11 Process 1100, Fig.12 In some aspects, in other examples, executing instructions may include running instructions, converting instructions, compiling instructions, and / or interpreting instructions, etc.

[0049] In some aspects, UE 120 may include components for receiving initial timing advance information from base station 110 in a msg2 communication of a four-step RACH procedure based at least in part on a subcarrier spacing in a cell associated with base station 110, components for sending to base station 110 a msg3 communication using an initial timing advance based at least in part on the initial timing advance information, components for receiving updated timing advance information from base station 110 for resolving timing advance wrap-around between UE 120 and base station 110 based at least in part on the base station detecting the msg3 communication, etc. In some aspects, such components may include in conjunction with Figure 2 One or more components of UE 120 are depicted, such as controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, etc.

[0050] In some aspects, base station 110 may include means for sending initial timing advance information to UE 120 in a msg2 communication of a four-step RACH procedure based at least in part on a subcarrier spacing in a cell associated with base station 110, means for receiving from UE 120 a msg3 communication using an initial timing advance based at least in part on the initial timing advance information, means for sending to UE 120 updated timing advance information for resolving a timing advance wrap between UE 120 and base station 110 based at least in part on base station 110 detecting the msg3 communication, etc. In some aspects, such means may include in conjunction with Figure 2 One or more components of the base station 110 are depicted, such as antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, etc.

[0051] Although Figure 2 The blocks in the 200 and 210 are shown as distinct components, but the functionality described above with respect to the blocks may be implemented in a single hardware, software, or combined component, or in various combinations of components. For example, the functionality described with respect to the transmit processor 264, the receive processor 258, and / or the TX MIMO processor 266 may be performed by, or under the control of, the controller / processor 280.

[0052] As mentioned above, providing Figure 2 As an example. Other examples can be related to Figure 2 Different than described.

[0053] Figure 3 is a diagram illustrating an example 300 of a two-step RACH procedure according to the present disclosure. Figure 3 As shown in FIG. 1 , base station 110 and UE 120 may communicate with each other in a wireless network (eg, wireless network 100 ) to perform a two-step RACH procedure.

[0054] As shown by reference numeral 305, the base station 110 may send one or more synchronization signal blocks (SSBs) and random access configuration information, and the UE 120 may receive one or more synchronization signal blocks (SSBs) and random access configuration information. In some aspects, the random access configuration information may be sent in system information (e.g., in one or more system information blocks (SIBs), etc.) and / or SSBs, and / or indicated by the system information and / or SSBs. Additionally or alternatively, the random access configuration information may be sent in a radio resource control (RRC) message. The random access configuration information may include one or more parameters to be used in a two-step RACH process, such as one or more parameters for sending a random access message (RAM), receiving a random access response (RAR) to a RAM, and the like.

[0055] As shown by reference numeral 310, UE 120 may send a RAM preamble, and base station 110 may receive the RAM preamble. As shown by reference numeral 315, UE 120 may send a RAM payload, and base station 110 may receive the RAM payload. As shown, as part of the initial (or first) step of the two-step RACH process, UE 120 may send a RAM preamble and a RAM payload to base station 110. In some aspects, RAM may be referred to as message A, msgA, first message, initial message, etc. in the two-step RACH process. In addition, in some aspects, RAM preamble may be referred to as message A preamble, msgA preamble, preamble, physical random access channel (PRACH) preamble, etc., and RAM payload may be referred to as message A payload, msgA payload, msgA physical uplink shared channel (PUSCH), payload, etc. In some aspects, RAM may include some or all of the contents of message 1 (msg1) and message 3 (msg3) of the four-step RACH process, which will be described in more detail below. For example, the RAM preamble may include some or all of the contents of message 1 (e.g., a PRACH preamble), and the RAM payload may include some or all of the contents of message 3 (e.g., a UE identifier, uplink control information (UCI), a PUSCH transmission, etc.).

[0056] As indicated by reference numeral 320, the base station 110 may receive the RAM preamble code transmitted by the UE 120. If the base station 110 successfully receives and decodes the RAM preamble code, the base station 110 may then receive and decode the RAM payload.

[0057] As shown by reference numeral 325, the base station 110 may send a RAR (sometimes referred to as a RAR message). As shown, the base station 110 may send a RAR message as part of the second step of the two-step RACH process. In some aspects, the RAR message may be referred to as message B, msgB, or a second message in the two-step RACH process. The RAR message may include some or all of the contents of message 2 (msg2) and message 4 (msg4) of the four-step RACH process. For example, the RAR message may include a detected PRACH preamble identifier, a detected UE identifier, timing advance information (e.g., a timing advance value, a timing advance command, etc.), contention resolution information, etc.

[0058] As part of the second step of the two-step RACH process, the base station 110 may send a physical downlink control channel (PDCCH) communication for the RAR, as shown by reference numeral 330. The PDCCH communication may schedule a physical downlink shared channel (PDSCH) communication including the RAR. For example, the PDCCH communication may indicate resource allocations for the PDSCH communication (e.g., in downlink control information (DCI)).

[0059] As part of the second step of the two-step RACH process, the base station 110 may send a PDSCH communication for the RAR according to the scheduling of the PDCCH communication, as shown by reference numeral 335. The RAR may be included in a medium access control (MAC) protocol data unit (PDU) of the PDSCH communication. As shown by reference numeral 340, if the UE 120 successfully receives the RAR, the UE 120 may send a hybrid automatic repeat request (HARQ) acknowledgment (ACK).

[0060] As mentioned above, providing Figure 3 As an example. Other examples can be related to Figure 3 Different than described.

[0061] Figure 4 4 is a diagram illustrating an example 400 of a four-step RACH procedure according to the present disclosure. Figure 4 As shown in FIG. 1 , base station 110 and UE 120 may communicate with each other in a wireless network (eg, wireless network 100 ) to perform a four-step RACH procedure.

[0062] As shown by reference numeral 405, the base station 110 may send one or more SSBs and random access configuration information, and the UE 120 may receive one or more SSBs and random access configuration information. In some aspects, the random access configuration information may be sent in system information (e.g., in one or more SIBs, etc.) and / or SSBs, and / or indicated by system information and / or SSBs. Additionally or alternatively, the random access configuration information may be sent in an RRC message. The random access configuration information may include one or more parameters to be used in the RACH process, such as one or more parameters for sending a RAM, one or more parameters for receiving a RAR, etc.

[0063] As shown by reference numeral 410, UE 120 may send a RAM, which may include a preamble (sometimes referred to as a random access preamble, a PRACH preamble, a RAM preamble, etc.). The message including the preamble may be referred to as message 1 in a four-step RACH procedure, msg1, MSG1, a first message, an initial message, etc. The random access message may include a random access preamble identifier.

[0064] As shown by reference numeral 415, the base station 110 may send a RAR in reply to the preamble. The message including the RAR may be referred to as message 2, msg2, MSG2, or a second message in a four-step RACH process. In some aspects, the RAR may indicate a detected random access preamble identifier (e.g., received from the UE 120 in msg1). Additionally or alternatively, the RAR may indicate a resource allocation to be used by the UE 120 to send message 3 (msg3).

[0065] In some aspects, as part of the second step of the four-step RACH process, the base station 110 may send a PDCCH communication for the RAR. The PDCCH communication may schedule a PDSCH communication including the RAR. For example, the PDCCH communication may indicate a resource allocation for the PDSCH communication. Similarly, as part of the second step of the four-step RACH process, the base station 110 may send a PDSCH communication for the RAR according to the scheduling of the PDCCH communication. The RAR may be included in the MAC PDU of the PDSCH communication.

[0066] As shown by reference numeral 420, UE 120 may send an RRC connection request message. The RRC connection request message may be referred to as message 3, msg3, MSG3, or a third message of the four-step RACH procedure. In some aspects, the RRC connection request may include a UE identifier, a UCI, a PUSCH communication (e.g., an RRC connection request), etc.

[0067] As shown by reference numeral 425, the base station 110 may send an RRC connection setup message. The RRC connection setup message may be referred to as message 4, msg4, MSG4, or a fourth message of the four-step RACH procedure. In some aspects, the RRC connection setup message may include a detected UE identifier, timing advance information (e.g., a timing advance value, a timing advance command, etc.), contention resolution information, etc. As shown by reference numeral 430, if the UE 120 successfully receives the RRC connection setup message, the UE 120 may send a HARQ ACK.

[0068] As mentioned above, providing Figure 4 As an example. Other examples can be related to Figure 4 Different than described.

[0069] Figure 5 is a diagram showing one or more examples 500 of PRACH preamble formats that can be used in a two-step RACH process or a four-step RACH process according to the present disclosure. For example, as described above, an initial uplink RACH communication sent from a UE to a base station (e.g., a preamble portion of a msg1 communication, a msgA communication, etc. in a four-step RACH process, etc.) may include a preamble sequence generated or selected by the UE. During the RACH process, the UE and the base station may use the preamble sequence to uniquely identify the UE. For example, the base station may use the preamble sequence and a random access radio network temporary identifier (RA-RNTI) to address a downlink RACH communication to the UE (e.g., a msg2 communication in a four-step RACH process, a msgB communication in a two-step RACH process, etc.).

[0070] Generally, the preamble sequence sent in the initial uplink RACH communication may have a long sequence format or a short sequence format, and the allowed formats of the preamble sequence may depend on one or more factors, such as the frequency band, bandwidth, subcarrier spacing, etc. used for communication between the UE and the base station. Figure 5 In the , the PRACH preamble formats shown each have a short sequence format in which a cyclic prefix precedes the preamble sequence sent in one or more repetitions, and an optional guard time may follow one or more repetitions of the preamble sequence. Typically, the duration of the cyclic prefix, the number of repetitions of the preamble sequence, and the duration of the guard time (if any) may vary between different PRACH preamble formats that are configured to be aligned in time with OFDM symbol boundaries for data transmissions having the same parameter set (numerology) as the PRACH preamble. For example, the following table provides the case where the short PRACH preambles all have a length of 139 bits, the subcarrier spacing is 15kHz, and the communication bandwidth is 2.16MHz, Figure 5Configuration details of various short PRACH preamble codes are shown in FIG.

[0071]

[0072] Table 1: Short PRACH preamble code format

[0073] Therefore, if Figure 5 As shown in the table provided above, a PRACH preamble with a short format may typically cover 2, 4, 6, or 12 OFDM symbols, with a cyclic prefix clustered at the start of the burst and with or without a guard time at the end of the burst. The cyclic prefix and guard time may typically be constrained to be no longer than the sequence, for example, to avoid timing advance wraparound, which may create ambiguity related to the OFDM symbol boundaries that are expected to be aligned in time with the PRACH preamble. However, the cyclic prefix and guard time are included in the PRACH preamble to account for the round-trip delay in the cell and the delay spread due to multipath propagation, whereby the cyclic prefix and guard time need to be long enough to absorb the round-trip delay, delay spread, etc. In this regard, the supported cell size may typically depend on the cyclic prefix duration (e.g., a longer cyclic prefix duration may absorb a larger round-trip delay and delay spread, thereby supporting a larger cell size). In a similar aspect, to support the target cell size, the supported PRACH preamble formats may be limited to those with a cyclic prefix duration long enough to absorb expected round trip delay, delay spread, etc. in a cell with the target cell size.

[0074] However, this may create challenges in higher frequency bands (e.g., greater than 52.6 GHz, up to 71 GHz, etc.), where large subcarrier spacings (e.g., 960 kHz, 1.9 MHz, 3.8 MHz, etc.) may be required to support larger bandwidths with the same Fast Fourier Transform (FFT) size as in lower frequency bands. Thus, while the short PRACH preamble format may generally scale in proportion to the subcarrier spacing (e.g., larger subcarrier spacings generally result in shorter symbol durations), scaling at the (multiple) larger subcarrier spacings used in higher frequency bands is expected to significantly reduce the cyclic prefix duration, and therefore reduce the supportable cell size. For example, at a subcarrier spacing of 960 kHz, the cyclic prefix in a PRACH preamble with format A1 will have a duration of 0.146 μs, the cyclic prefix and guard time in a PRACH preamble with format B1 will have durations of 0.11 μs and 0.037 μs, respectively, etc. As a result, a shorter cyclic prefix and a shorter guard time in a scaled short PRACH preamble will significantly limit the supportable round trip time and / or delay spread, and thus the supportable cell size.

[0075] Some aspects described herein relate to techniques and apparatus that can implement one or more RACH processes that increase the supportable cell size in a higher frequency band by allowing a cyclic prefix to exceed a full symbol duration. For example, in the case of a four-step RACH process, allowing a cyclic prefix to exceed a full symbol duration may result in a timing wraparound in which the base station may not be able to distinguish between a timing advance t and a timing advance t+k / SCS, where the timing advance generally indicates an amount of time for an uplink communication to travel from a UE to a base station, t is a portion of the timing advance within a full symbol duration, SCS represents a subcarrier spacing used in a cell associated with the base station, and k is a non-negative integer having a value of {0, 1, ..., M}. Thus, in the case of a four-step RACH process, the base station may (e.g., in a msg2 communication) send initial timing advance information including a value of t to the UE, and subsequent messages (e.g., msg2 retransmissions, msg3 transmissions and / or retransmissions, msg3 PDCCHs, msg4 transmissions, etc.) may be used to determine the value of k, thereby resolving the timing wraparound. Alternatively, in the case of a two-step RACH procedure, the base station may determine the timing t versus t+k / SCS based on the msgA PUSCH payload so that the correct timing advance may be unambiguously indicated in the msgB communication. Therefore, because the timing wraparound problem exceeding one symbol duration may be more pronounced in a four-step RACH procedure and less likely to occur in a two-step RACH procedure, the base station may configure different PRACH parameters for the two-step RACH procedure and the four-step RACH procedure. In this way, the base station may support cells capable of operating at high frequencies, large subcarrier spacings, large bandwidths, etc., without having to scale the PRACH preamble proportionally in a manner that may limit the supportable cell size due to the shorter symbol duration.

[0076] As mentioned above, providing Figure 5 As an example. Other examples can be related to Figure 5 Different than described.

[0077] Figure 6 6 is a diagram illustrating one or more examples 600 of a RACH transmission process in a higher frequency band according to the present disclosure. Figure 6 As shown in FIG. 1 , a base station 110 and a UE 120 may communicate with each other in a wireless network (eg, wireless network 100 ) to perform a two-step RACH procedure and / or a four-step RACH procedure.

[0078] like Figure 6As shown in reference numeral 610, the base station 110 may send random access configuration information and the UE 120 may receive the random access configuration information, the random access configuration information including a PRACH parameter set for a two-step RACH procedure and a four-step RACH procedure. In some aspects, the random access configuration information may be sent in system information (e.g., in one or more SIBs, etc.) and / or SSBs, and / or indicated by system information and / or SSBs. Additionally or alternatively, the random access configuration information may be sent in an RRC message. Typically, as described above, the random access configuration information may include parameters to be used in a RACH procedure, such as parameters for sending a random access message, parameters for receiving a random access response (RAR) to a random access message, and the like. In addition, in some aspects, the random access configuration information may indicate different PRACH parameter sets for a two-step RACH procedure and a four-step RACH procedure to be used in a cell associated with the base station.

[0079] For example, as described above, the base station 110 and the UE 120 may communicate in a frequency associated with a subcarrier spacing, which may result in a full symbol duration that is shorter than the cyclic prefix duration. In this case, a timing advance wraparound may occur, whereby the base station 110 may not be able to distinguish between a timing advance t and t+k / SCS, where t is a portion of the timing advance within the full symbol duration, SCS represents the subcarrier spacing used in a cell associated with the base station, and k is a non-negative integer having a value of {0, 1, ..., M}. However, a timing wraparound of more than one symbol duration may be more noticeable in a four-step RACH procedure and is less likely to occur in a two-step RACH procedure because the base station 110 can determine the timing advance t and t+k / SCS based on the msgA PUSCH payload. Therefore, because the base station 110 can determine the correct timing advance and indicate the correct timing advance in msgB without any ambiguity, the random access configuration provided to the UE can configure different PRACH parameters for the two-step RACH procedure and the four-step RACH procedure.

[0080] For example, in some aspects, a PRACH parameter set for a two-step RACH procedure can be the same as a parameter set used for data transmission, which can generally simplify processing by the base station 110. On the other hand, due to the possibility of timing advance ambiguity caused by timing advance wraparound, the four-step RACH procedure can be configured to use a PRACH parameter set with a subcarrier spacing that is smaller than the subcarrier spacing used for data transmission in the cell. In addition, when a cell associated with the base station supports the two-step RACH procedure and the four-step RACH procedure, the two-step RACH occasion (RACH occasion, RO) and the four-step RO can use different PRACH parameter sets (e.g., the two-step RO can use the same PRACH parameter set as the data transmission, while the four-step RO can use a PRACH parameter set based on a smaller subcarrier spacing to allow a larger timing advance that may exceed a full symbol duration).

[0081] like Figure 6 As further shown by reference numeral 620 in FIG. 1 , the UE 120 may send a PRACH preamble and the base station 110 may receive the PRACH preamble to initiate a RACH procedure based at least in part on a PRACH parameter set associated with the RACH procedure. For example, in the case where the UE 120 initiates a two-step RACH procedure, the UE 120 may send a PRACH preamble in a msgA communication during a two-step RO using a PRACH parameter set based on a subcarrier spacing that is the same as a subcarrier spacing used in the cell for data transmission. Alternatively, in the case where the UE 120 initiates a four-step RACH procedure, the UE 120 may send a PRACH preamble in a msg1 communication during a four-step RO using a PRACH parameter set based on a subcarrier spacing that is smaller than a subcarrier spacing used in the cell for data transmission.

[0082] like Figure 6As further shown by reference numeral 630 in FIG. 1 , the UE 120 and the base station 110 may exchange additional RACH messages to resolve the timing advance between the UE 120 and the base station 110 based at least in part on the subcarrier spacing used in the cell associated with the base station 110. For example, as described above, since the random access configuration information indicates that the cyclic prefix of the PRACH preamble is allowed to exceed the full symbol duration, the base station 110 is generally unable to distinguish between the timing advance t and the timing advance t+k / SCS based solely on the PRACH preamble. Therefore, in the case of a two-step RACH procedure, the base station 110 may first detect the PRACH preamble with an ambiguous timing advance and may resolve the timing wraparound based on the msgA PUSCH payload. In this manner, the base station may determine the value of k, which may be a non-negative integer, and may accordingly indicate in the msgB communication without any ambiguity the timing advance that the UE 120 will use for subsequent uplink communications. Alternatively, in the case of a four-step RACH procedure, base station 110 may provide initial timing advance information to UE 120 (e.g., in msg2 communications), and subsequent RACH messages may be used to resolve the value of k so that UE 120 may be provided with an updated timing advance for subsequent uplink communications. Further details regarding different techniques for resolving the value of k, and thereby resolving timing advance wraparound between UE 120 and base station 110, that may be used in a four-step RACH procedure are described below.

[0083] As mentioned above, providing Figure 6 As an example. Other examples can be related to Figure 6 Different than described.

[0084] Figure 7 is a diagram illustrating one or more examples 700 of a RACH transmission process in a higher frequency band according to the present disclosure. Figure 7 As shown in , base station 110 and UE 120 can communicate with each other in a wireless network (e.g., wireless network 100) to perform a four-step RACH procedure. In addition, as described herein, the four-step RACH procedure can be associated with a random access configuration that allows a PRACH preamble to have a cyclic prefix that exceeds a full symbol duration, which depends on the subcarrier spacing used in a cell associated with base station 110.

[0085] like Figure 7As shown at reference numeral 710 in FIG. 1 , UE 120 may send, and base station 110 may receive, a msg1 communication including a PRACH preamble having a cyclic prefix and one or more repeated sequences following the cyclic prefix. Additionally, in some aspects, the PRACH preamble may include a guard time following the one or more repeated sequences. For example, the PRACH preamble may have a short PRACH preamble format, such as Figure 5 In some aspects, the random access configuration may be based at least in part on the subcarrier spacing used in a cell associated with a base station, allowing a cyclic prefix of the PRACH preamble to exceed a full symbol duration, as described above. For example, rather than scaling the cyclic prefix duration proportionally to the subcarrier spacing (which may limit the supportable cell size), the cyclic prefix duration may exceed the full symbol duration, and subsequent messages exchanged during the four-step RACH process may be used to resolve any timing ambiguity that may arise due to the cyclic prefix duration possibly exceeding the full symbol duration.

[0086] More specifically, if Figure 7 As further shown by reference numeral 720 in the figure, the base station 110 may send a msg2 communication, and the UE 120 may receive the msg2 communication, which includes a random access response (RAR) that provides initial timing advance information. For example, as described above, the base station 110 may receive a PRACH preamble at a specific time that enables the base station 110 to determine the timing advance t within a full symbol duration that depends on the subcarrier spacing used in the cell. However, because the PRACH preamble has a cyclic prefix that may (or may not) exceed the full symbol duration, the base station 110 may not be able to distinguish between the timing advance t+k / SCS and the timing advance t within the full symbol duration, where k is a non-negative integer with a value of {0, 1, ..., M}. Therefore, in some aspects, the msg2 communication sent to the UE 120 as a reply to the msg1 communication may indicate a value of t, where the base station 110 is able to unambiguously detect the value of t based on the time when the PRACH preamble is received, and subsequent RACH messages exchanged during the four-step RACH process can be used to parse the value of k to determine the correct timing advance.

[0087] For example, Figure 7As further shown by reference numeral 730 in the figure, the UE 120 may send the msg3 communication using the initial timing advance indicated in the msg2 communication. Therefore, as shown by reference numeral 740, the base station 110 may attempt to detect the msg3 communication using multiple hypotheses based on different possible timing advances (e.g., different k values). For example, in some aspects, the base station 110 may attempt to detect the msg3 communication using an initial hypothesis of "assuming that the msg3 communication has aligned timing (e.g., k=0)", and if the base station 110 fails to detect the msg3 communication using the initial hypothesis assuming aligned timing, the base station 110 may further attempt to detect the msg3 communication using additional hypotheses (e.g., k={1,...,M}) until the msg3 communication is detected. For example, in some aspects, multiple hypotheses for detecting the msg3 communication may be performed on a demodulation reference signal (DMRS) associated with the msg3 communication, a DMRS associated with the msg3 communication, a PUSCH, and the like. In this way, the base station 110 may resolve the value of k and thereby resolve the correct timing advance.

[0088] Additionally or alternatively, as further indicated by reference numeral 730, UE 120 may optionally send a timing resolution reference signal to base station 110 prior to sending the msg3 communication. In this case, base station 110 may detect the correct timing advance (e.g., resolve the value of k) by applying multiple timing hypotheses to the timing resolution reference signal, and then detecting the msg3 communication based on the correct timing advance determined from the timing resolution reference signal. In addition, in some aspects, the resources allocated to the msg3 communication (and the timing resolution reference signal, if used) may be configured to have one or more symbol gaps in time and one or more guard resource elements and / or resource blocks to mitigate potential interference to other (synchronized) uplink transmissions. For example, because the timing resolution reference signal and / or msg3 communication are sent with the initial timing advance indicated in the msg2 communication before the value of k is resolved, the timing resolution reference signal and / or msg3 communication may not be correctly synchronized. Therefore, additional symbol gaps in time and guard resource elements and / or resource blocks may be used to reduce potential interference to other correctly synchronized uplink transmissions.

[0089] like Figure 7As further shown by reference numeral 750 in , the base station 110 may send, and the UE 120 may receive, a msg4 communication including updated timing advance information that resolves any ambiguity between the timing advance t and the timing advance wraparound t+k / SCS. For example, as described above, the base station 110 may determine the value of k based on which of a plurality of hypotheses causes the base station 110 to successfully detect the msg3 communication and / or based on the timing determined by the timing resolution reference signal. Thus, the base station 110 may signal the updated timing advance information in a msg4 PDSCH communication or a msg4 PDCCH communication that schedules the msg4 PDSCH communication. Furthermore, in some aspects, the base station 110 may signal only the resolved value of k (e.g., indicating a non-negative integer value) so that the UE 120 may add an appropriate time period to the initial timing advance indicated in the msg2 communication. For example, if the base station 110 signals k=0 (e.g., based on detecting a msg3 communication using aligned timing), the updated timing advance may be the same as the initial timing advance. In another example, if base station 110 signals k=1 (e.g., based on detecting that msg3 communications differ by one full symbol duration and are thus misaligned), UE 120 may add one full symbol duration to the initial timing advance indicated in msg2 communications. Figure 7 As further shown by reference numeral 760, subsequent uplink transmissions from UE 120 to base station 110 (including acknowledgments for msg4 communications) may be sent based on the updated timing advance information.

[0090] As mentioned above, providing Figure 7 As an example. Other examples can be found in reference Figure 7 Described differently.

[0091] Figure 8 8 is a diagram illustrating one or more examples 800 of a RACH transmission process in a higher frequency band according to the present disclosure. Figure 8 As shown in , a base station 110 and a UE 120 can communicate with each other in a wireless network (e.g., wireless network 100) to perform a four-step RACH procedure. In addition, as described herein, the four-step RACH procedure can be associated with a random access configuration that allows a PRACH preamble to have a cyclic prefix that exceeds a full symbol duration, which depends on the subcarrier spacing used in a cell associated with the base station 110. In addition, the random access configuration can define a duration of a random access response (RAR) window that allows the UE 120 and the base station 110 to exchange multiple msg2 communications and msg3 communications until the correct timing advance is resolved.

[0092] like Figure 8 As shown in reference numeral 810, UE 120 may send, and base station 110 may receive, msg1 communications that include a PRACH preamble having a cyclic prefix and one or more repeated sequences following the cyclic prefix. Additionally, in some aspects, the PRACH preamble may include a guard time following the one or more repeated sequences. For example, the PRACH preamble may have a short PRACH preamble format, such as Figure 5 In some aspects, as described above, the random access configuration may allow a cyclic prefix of a PRACH preamble to exceed a full symbol duration, which is based at least in part on the subcarrier spacing used in a cell associated with a base station. For example, rather than scaling the cyclic prefix duration proportionally to the subcarrier spacing (which may limit the supportable cell size), the cyclic prefix duration may exceed the full symbol duration, and subsequent messages exchanged during the four-step RACH process may be used to resolve any timing ambiguity that may arise due to the cyclic prefix duration being able to exceed the full symbol duration.

[0093] like Figure 8 As further shown by reference numeral 820 in FIG. 1 , base station 110 may send, and UE 120 may receive, msg2 communications that include a RAR providing initial timing advance information. For example, as described above, the initial timing advance information may indicate a value of t that is a timing advance that base station 110 can unambiguously detect based on the time at which the PRACH preamble is received within a full symbol duration. Thus, as Figure 8 As further shown in reference numeral 830, UE 120 may send msg3 communication using the initial timing advance indicated in msg2 communication. Therefore, as shown in reference numeral 840, base station 110 may attempt to detect msg3 communication using the initial timing advance (e.g., assuming that the value of k is 0). As further shown in reference numeral 850, if base station 110 cannot detect msg3 communication using the initial timing advance, base station 110 may retransmit msg2 communication with updated timing advance information (e.g., the value of k is 1).

[0094] Thus, as indicated by reference numeral 860, the UE 120 may retransmit the msg3 communication using the updated timing advance. In some aspects, such an exchange may be repeated until the base station 110 is able to successfully detect the msg3 communication. In some aspects, in order to allow the base station 110 to send multiple msg2 communications with different timing advances and allow the UE 120 to attempt multiple msg3 communications using different timing advances, the base station 110 may configure an extended RAR window for the msg2 communication. For example, in some aspects, the extended RAR window may generally have a duration that depends on the supported cell size, and the supported cell size may constrain the possible values ​​of k based on the potential round-trip delay and delay spread that will be absorbed by the cyclic prefix. For example, the base station 110 may determine that for the first cell size, the possible values ​​of k may be 0 or 1, or for a larger cell size, the possible values ​​of k may be 0, 1, or 2. In this regard, depending on the supported cell size and the possible round-trip delay that may be experienced in the cell, the base station 110 may determine the number of possible hypotheses required to resolve the value of k and configure the RAR window duration accordingly. Furthermore, because the base station 110 may transmit multiple msg2 communications with different timing advances, the UE 120 may continue to monitor the downlink channel for the msg2 communication after transmitting the msg3 communication as a reply to the correctly detected msg2 communication.

[0095] like Figure 8 As further shown by reference numeral 870, after the base station 110 is able to successfully detect the msg3 communication, the base station 110 may send the msg4 communication, and the UE 120 may receive the msg 4 communication. For example, if the base station 110 is able to detect the msg3 communication using the initial timing advance, the base station 110 will not retransmit the msg2 communication, but will send the msg4 communication as a reply to the msg3 communication sent using the initial timing advance. Alternatively, if the base station 110 is unable to detect the msg3 communication using the initial timing advance, but successfully detects a subsequent msg3 communication using a different timing advance, the base station 110 will send the msg4 communication as a reply to the successfully detected msg3 communication. Therefore, as Figure 8 As further shown by reference numeral 880, subsequent uplink transmissions from UE 120 to base station 110 (including acknowledgment of msg4 communication) may be sent based on updated timing advance information, which may correspond to the timing advance for msg3 communication successfully detected by base station 110 (e.g., msg3 communication sent by UE 120 just prior to msg4 communication).

[0096] As mentioned above, providing Figure 8 As an example. Other examples can be related to Figure 8Different than described.

[0097] Fig. 9 is a diagram illustrating one or more examples 900 of a RACH transmission process in a higher frequency band according to the present disclosure. Fig. 9 As shown in , base station 110 and UE 120 can communicate with each other in a wireless network (e.g., wireless network 100) to perform a four-step RACH procedure. In addition, as described herein, the four-step RACH procedure can be associated with a random access configuration that allows a PRACH preamble to have a cyclic prefix that exceeds a full symbol duration, which depends on the subcarrier spacing used in a cell associated with base station 110.

[0098] like Fig. 9 As shown at reference numeral 910, UE 120 may transmit and base station 110 may receive msg1 communications, as described in further detail above, that include a PRACH preamble with a cyclic prefix that is allowed to exceed a full symbol duration. Fig. 9 As further shown by reference numeral 920 in FIG. 1 , base station 110 may send, and UE 120 may receive, msg2 communications that include a RAR providing initial timing advance information. For example, as described above, the initial timing advance information may indicate a value of t that is a timing advance that base station 110 can unambiguously detect based on the time at which the PRACH preamble is received within a full symbol duration. Thus, as Fig. 9 As further shown in reference numeral 930, UE 120 may use the initial timing advance indicated in msg2 communication to send msg3 communication. Therefore, as shown in reference numeral 940, base station 110 may attempt to detect msg3 communication using the initial timing advance (eg, assuming the value of k is 0).

[0099] As further shown by reference numeral 950, if the base station 110 is unable to detect the msg3 communication using the initial timing advance, the base station 110 may send a PDCCH communication and the UE 120 may receive the PDCCH communication, the PDCCH communication including downlink control information (DCI) that triggers the retransmission of the msg3 communication using the updated timing advance information (e.g., the value of k is 1). Therefore, as shown by reference numeral 960, the UE 120 may retransmit the msg3 communication using the updated timing advance. In some aspects, this exchange may be repeated until the base station 110 is able to successfully detect the msg3 communication. Therefore, in this case, the UE 120 may send the msg3 communication after successfully detecting the msg2 communication, and may then monitor the PDCCH for the DCI for triggering the retransmission of the msg3 communication or the PDCCH for the msg4 PDCCH communication for scheduling the msg4 PDSCH communication. In this way, the base station 110 can send one or more PDCCH communications to trigger one or more retransmissions of msg3 communications using different timing advances until the msg3 communication is successfully detected. In some aspects, the initial timing advance can be based on k whose value is 0, and each PDCCH including a DCI for triggering a retransmission of msg3 communication can include a k value (ranging from 1 to M) to indicate the updated timing advance. For example, in some aspects, the k value can be indicated in a reserved field of a HARQ process identifier (e.g., a 4-bit HARQ process number for a temporary cell radio network temporary identifier (TC-RNTI)). Alternatively, a time domain resource allocation (TDRA) table may include different entries corresponding to different k values, and the PDCCH may indicate one of the entries in the TDRA table.

[0100] like Fig. 9 As further shown by reference numeral 970, after the base station 110 is able to successfully detect the msg3 communication, the base station 110 may send the msg4 communication, and the UE 120 may receive the msg 4 communication. For example, if the base station 110 is able to detect the msg3 communication using the initial timing advance, the base station 110 will not send a PDCCH communication for triggering a retransmission of the msg3 communication, but will instead send the msg4 communication as a reply to the msg3 communication sent with the initial timing advance. Alternatively, if the base station 110 is unable to detect the msg3 communication using the initial timing advance, but successfully detects a subsequent msg3 communication using a different timing advance, the base station 110 will send the msg4 communication as a reply to the successfully detected msg3 communication. Thus, as Fig. 9As further shown by reference numeral 980, subsequent uplink transmissions from UE 120 to base station 110 (including confirmation of msg4 communication) may be sent based on updated timing advance information, which may correspond to the timing advance for msg3 communication successfully detected by base station 110 (e.g., msg3 communication sent by UE 120 just prior to msg4 communication).

[0101] As mentioned above, providing Fig. 9 As an example. Other examples can be found in reference Fig. 9 Different than described.

[0102] FIG. 10A to FIG. 10B 1 is a diagram illustrating one or more examples 1000 of a RACH transmission process in a higher frequency band according to the present disclosure. FIG. 10A to FIG. 10B As shown, base station 110 and UE 120 can communicate with each other in a wireless network (e.g., wireless network 100) to perform a four-step RACH process. In addition, as described herein, the four-step RACH process can be associated with a random access configuration that allows a PRACH preamble to have a cyclic prefix that exceeds a full symbol duration, which depends on the subcarrier spacing used in a cell associated with base station 110.

[0103] like FIG. 10A to FIG. 10B As shown at reference numeral 1010, UE 120 may transmit and base station 110 may receive msg1 communications, which may include a PRACH preamble with a cyclic prefix that is allowed to exceed a full symbol duration, as described in further detail above. FIG. 10A to FIG. 10B As further shown in the figure by reference numeral 1020, the base station 110 may send a msg2 communication and the UE 120 may receive the msg2 communication, the msg2 communication including initial timing advance information providing a plurality of timing advance commands (e.g., with a timing advance of t+k / SCS, including a plurality of different values ​​of k). In addition, as shown, the msg2 communication may include a plurality of uplink grants (e.g., different uplink resources) to allow the UE 120 to send a msg3 communication in a plurality of repetitions based on the plurality of timing advance commands.

[0104] For example, Fig. 10AAs shown by reference numeral 1030 in FIG. 1 , UE 120 may send multiple repetitions of msg3 communication, and base station 110 may receive multiple repetitions of msg3 communication, the multiple repetitions of msg3 communication being sent at different timing advances (e.g., at a first timing advance t, a second timing advance t+1 / SCS, a third timing advance t+2 / SCS, etc.). In this manner, the multiple repetitions of msg3 communication may increase the coverage and reliability of msg3 communication in addition to ensuring that base station 110 will be able to successfully detect msg3 communication, wherein at least one msg3 communication will be sent at the correct timing. Therefore, as Fig. 10A As further shown in reference numeral 1040, the base station 110 may send a msg4 communication and the UE 120 may receive the msg4 communication, the msg4 communication including the updated timing advance information. For example, in some aspects, based on one of the multiple repetitions of the msg3 communication being successfully detected by the base station 110, the msg4 communication may explicitly indicate the k value to be used for subsequent uplink transmissions.

[0105] Alternatively, if Fig. 10B As shown in reference number 1050-1, UE 120 may send a first transmission of msg3 communication using a first timing advance, and base station 110 may receive the first transmission of msg3 communication using the first timing advance. In this case, the random access configuration may indicate that the msg4 transmission timing does not overlap with the transmission timing of each msg3 communication. For example, if base station 110 is able to successfully detect the first transmission of msg3 communication using the first timing advance, base station 110 may send msg4 communication as a reply to the first transmission of msg3 communication before the transmission timing of the next msg3 communication. Therefore, if UE 120 does not detect msg4 communication before the transmission timing of the next msg3 communication, UE 120 may retransmit msg3 communication with a different timing advance. For example, in Fig. 10B In the example, reference numerals 1050-2 and 1050-N illustrate an example in which the UE 120 transmits a second msg3 communication (e.g., using a timing advance of t+1 / SCS) and an Nth msg 3 communication (e.g., using a timing advance of t+(N-1) / SCS) based at least in part on a failure to detect a msg4 communication before a corresponding msg3 transmission opportunity. In this case, Fig. 10BAs further shown in reference numeral 1060, the base station 110 may send and the UE 120 may receive a msg4 communication that implicitly indicates updated timing advance information. For example, in some aspects, the msg4 communication may implicitly indicate a k value to be used for subsequent uplink transmissions based on a timing advance for a msg3 communication successfully detected by the base station 110 (e.g., a msg3 communication sent by the UE 120 just before the msg4 communication).

[0106] Therefore, if FIG. 10A to FIG. 10B As further shown by reference numeral 1070, subsequent uplink transmissions from UE 120 to base station 110 (including acknowledgments for msg4 communications) may be sent based on the updated timing advance information.

[0107] As mentioned above, providing FIG. 10A to FIG. 10B is provided as one or more examples. Other examples may be related to FIG. 10A to FIG. 10B Different than described.

[0108] Fig.11 1 is a diagram illustrating an example process 1100 performed, for example, by a UE according to the present disclosure. Example process 1100 is an example of a UE (eg, UE 120, etc.) performing operations associated with a RACH transmission procedure in a higher frequency band.

[0109] like Fig.11 As shown in , in some aspects, process 1100 may include receiving initial timing advance information from a base station in a msg2 communication of a four-step RACH procedure based at least in part on subcarrier spacing in a cell associated with the base station (block 1110). For example, as described above, the UE may receive initial timing advance information from the base station in a msg2 communication of a four-step RACH procedure based at least in part on subcarrier spacing in a cell associated with the base station (e.g., using antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller / processor 280, memory 282, etc.).

[0110] like Fig.11 As further shown in FIG. 1 , in some aspects, process 1100 may include sending a msg3 communication to a base station using an initial timing advance based at least in part on initial timing advance information (block 1120). For example, as described above, a UE may send a msg3 communication to a base station (e.g., using controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, etc.) using an initial timing advance based at least in part on initial timing advance information.

[0111] like Fig.11As further shown in FIG. 1 , in some aspects, process 1100 may include receiving updated timing advance information from a base station based at least in part on the base station detecting msg3 communication, the updated timing advance information resolving a timing advance wrap between the UE and the base station (block 1130). For example, as described above, the UE may receive updated timing advance information from a base station based at least in part on the base station detecting msg3 communication (e.g., using antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller / processor 280, memory 282, etc.), the updated timing advance information resolving a timing advance wrap between the UE and the base station.

[0112] Process 1100 may include additional aspects, such as any single aspect or any combination of aspects described below, and / or in conjunction with one or more other processes described elsewhere herein.

[0113] In a first aspect, the initial timing advance information indicates an initial timing advance to be used for msg3 communication within a full symbol duration based at least in part on a subcarrier spacing.

[0114] In a second aspect, either alone or in combination with the first aspect, the updated timing advance information comprises a non-negative integer value indicating a time to be added to an initial timing advance for msg3 communication based at least in part on a full symbol duration.

[0115] In a third aspect, alone or in combination with one or more of the first and second aspects, the base station detects msg3 communication based on multiple timing assumptions, wherein the multiple timing assumptions include an alignment timing assumption based at least in part on an initial timing advance and one or more additional timing assumptions based at least in part on one or more possible values ​​of the timing advance wraparound between the UE and the base station.

[0116] In a fourth aspect, alone or in combination with one or more of the first to third aspects, a base station attempts to detect one or more of a DMRS or a PUSCH associated with msg3 communication based on a plurality of timing hypotheses.

[0117] In a fifth aspect, either alone or in combination with one or more of the first to fourth aspects, process 1100 includes sending a timing resolution reference signal to a base station prior to msg3 communication, and the base station may attempt to detect msg3 communication based on multiple timing hypotheses at least in part on timing information determined from the timing resolution reference signal.

[0118] In the sixth aspect, either alone or in combination with one or more of the first to fifth aspects, resources allocated to one or more of the timing resolution reference signals or msg3 communications are separated from one or more other uplink signals by one or more symbol gaps in time and by one or more protection resource elements or resource blocks.

[0119] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, updated timing advance information is received in a PDCCH or PDSCH associated with msg4 communication of a four-step RACH procedure.

[0120] In an eighth aspect, either alone or in combination with one or more of the first to seventh aspects, process 1100 includes sending one or more uplink communications including an acknowledgment of the msg4 communication to a base station based at least in part on the updated timing advance information.

[0121] In a ninth aspect, either alone or in combination with one or more of the first to eighth aspects, updated timing advance information is received in a retransmission of a msg2 communication based at least in part on a base station failing to detect a msg3 communication using an initial timing advance.

[0122] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, process 1100 includes retransmitting msg3 communication to a base station based on updated timing advance information, and receiving msg4 communication of a four-step RACH process from the base station based at least in part on the base station detecting msg3 communication based on updated timing advance information.

[0123] In an eleventh aspect, alone or in combination with one or more of the first to tenth aspects, a retransmission of the msg2 communication is received during a RAR window monitored by the UE, the duration of the RAR window being based at least in part on a supported cell size associated with the base station.

[0124] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, updated timing advance information is received in a PDCCH including a DCI triggering a retransmission of msg3 communication.

[0125] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, updated timing advance information is indicated in a HARQ process identifier field of a DCI that triggers retransmission of msg3 communication.

[0126] In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, the updated timing advance information is indicated by an entry in a TDRA table.

[0127] In the fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the initial timing advance information includes multiple timing advance commands and multiple resource allocations for msg3 communication, and the msg3 communication is sent in multiple repetitions at least in part based on the multiple timing advance commands and multiple resource allocations for msg3 communication.

[0128] In a sixteenth aspect, either alone or in combination with one or more of the first to fifteenth aspects, updated timing advance information is explicitly indicated in a msg4 communication of a four-step RACH procedure based at least in part on multiple repetitions of a msg3 communication.

[0129] In a seventeenth aspect, either alone or in combination with one or more of the first to sixteenth aspects, updated timing advance information is implicitly indicated by a msg4 communication received as a reply to one of multiple repetitions of a msg3 communication in a four-step RACH procedure.

[0130] In the eighteenth aspect, alone or in combination with one or more of the first to seventeenth aspects, process 1100 includes receiving random access configuration information from a base station, the random access configuration information including a first PRACH parameter set for a two-step RACH process and a second PRACH parameter set for a four-step RACH process.

[0131] In the nineteenth aspect, either alone or in combination with one or more of the first to eighteenth aspects, the first PRACH parameter set is the same as a data parameter set based at least in part on the subcarrier spacing in a cell associated with the base station, and the second PRACH parameter set is smaller than the data parameter set based at least in part on the subcarrier spacing in the cell associated with the base station.

[0132] although Fig.11 An example block diagram of process 1100 is shown, but in some aspects, process 1100 may include more Fig.11 The blocks depicted in the process 1100 may be more blocks, fewer blocks, different blocks, or blocks arranged differently. Additionally or alternatively, two or more blocks of the process 1100 may be executed in parallel.

[0133] Fig.12 1 is a diagram illustrating an example process 1200 performed, for example, by a base station according to the present disclosure. Example process 1200 is an example of a base station (eg, base station 110, etc.) performing operations associated with a RACH transmission procedure in a higher frequency band.

[0134] like Fig.12As shown in , in some aspects, process 1200 may include sending initial timing advance information to the UE in a msg2 communication of a four-step RACH procedure based at least in part on subcarrier spacing in a cell associated with the base station (block 1210). For example, as described above, the base station may send initial timing advance information to the UE in a msg2 communication of a four-step RACH procedure based at least in part on subcarrier spacing in a cell associated with the base station (e.g., using controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, etc.).

[0135] like Fig.12 As further shown in FIG. 1 , in some aspects, process 1200 may include receiving, from the UE, a msg3 communication using an initial timing advance based at least in part on initial timing advance information (block 1220). For example, as described above, the base station may receive, from the UE, a msg3 communication using an initial timing advance (e.g., using antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, etc.), the initial timing advance based at least in part on initial timing advance information.

[0136] like Fig.12 As further shown in FIG. 1 , in some aspects, process 1200 may include sending updated timing advance information to the UE based at least in part on the base station detecting the msg3 communication, the updated timing advance information resolving the timing advance wrap between the UE and the base station (block 1230). For example, as described above, the base station may send updated timing advance information to the UE (e.g., using controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, etc.) based at least in part on the base station detecting the msg3 communication, the updated timing advance information resolving the timing advance wrap between the UE and the base station.

[0137] Process 1200 may include additional aspects, such as any single aspect or any combination of aspects described below, and / or in conjunction with one or more other processes described elsewhere herein.

[0138] In a first aspect, the initial timing advance information indicates an initial timing advance to be used for msg3 communication within a full symbol duration based at least in part on a subcarrier spacing.

[0139] In a second aspect, either alone or in combination with the first aspect, the updated timing advance information comprises a non-negative integer value indicating a time to be added to an initial timing advance for msg3 communication based at least in part on a full symbol duration.

[0140] In a third aspect, either alone or in combination with one or more of the first and second aspects, process 1200 includes detecting msg3 communications based on multiple timing assumptions, the multiple timing assumptions including an alignment timing assumption based at least in part on an initial timing advance and one or more additional timing assumptions based at least in part on one or more possible values ​​of a timing advance wraparound between the UE and the base station.

[0141] In a fourth aspect, either alone or in combination with one or more of the first to third aspects, process 1200 includes attempting to detect one or more of a DMRS or a PUSCH associated with msg3 communication based on a plurality of timing hypotheses.

[0142] In a fifth aspect, either alone or in combination with one or more of the first to fourth aspects, process 1200 includes receiving a timing resolution reference signal from a UE prior to msg3 communication, and attempting to detect msg3 communication based on multiple timing hypotheses based at least in part on timing information determined based on the timing resolution reference signal.

[0143] In the sixth aspect, either alone or in combination with one or more of the first to fifth aspects, resources allocated to one or more of the timing resolution reference signals or msg3 communications are separated from one or more other uplink signals by one or more symbol gaps in time and by one or more protection resource elements or resource blocks.

[0144] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, updated timing advance information is sent in a PDCCH or PDSCH associated with msg4 communication of a four-step RACH procedure.

[0145] In an eighth aspect, either alone or in combination with one or more of the first to seventh aspects, process 1200 includes receiving one or more uplink communications including an acknowledgment of the msg4 communication from the UE based at least in part on the updated timing advance information.

[0146] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, updated timing advance information is sent in a retransmission of a msg2 communication based at least in part on a failure to detect a msg3 communication using an initial timing advance.

[0147] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, process 1200 includes receiving a retransmission of msg3 communication based on updated timing advance information from the UE, and sending msg4 communication of a four-step RACH process to the UE based at least in part on detecting the retransmission of msg3 communication based on updated timing advance information.

[0148] In an eleventh aspect, alone or in combination with one or more of the first to tenth aspects, retransmissions of msg2 communications are sent during a RAR window monitored by the UE, the duration of the RAR window being based at least in part on a supported cell size associated with the base station.

[0149] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, updated timing advance information is sent in a PDCCH including a DCI triggering a retransmission of msg3 communication.

[0150] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, updated timing advance information is indicated in a HARQ process identifier field of a DCI that triggers retransmission of msg3 communication.

[0151] In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, the updated timing advance information is indicated by an entry in a TDRA table.

[0152] In the fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the initial timing advance information includes multiple timing advance commands and multiple resource allocations for msg3 communication, and the msg3 communication is received in multiple repetitions at least in part based on the multiple timing advance commands and multiple resource allocations for msg3 communication.

[0153] In a sixteenth aspect, either alone or in combination with one or more of the first to fifteenth aspects, updated timing advance information is explicitly indicated in a msg4 communication of a four-step RACH procedure based at least in part on multiple repetitions of a msg3 communication.

[0154] In a seventeenth aspect, either alone or in combination with one or more of the first to sixteenth aspects, updated timing advance information is implicitly indicated by a msg4 communication of a four-step RACH procedure sent as a reply to one of multiple repetitions of a msg3 communication.

[0155] In the eighteenth aspect, alone or in combination with one or more of the first to seventeenth aspects, process 1200 includes sending random access configuration information to the UE, the random access configuration information including a first PRACH parameter set for a two-step RACH process and a second PRACH parameter set for a four-step RACH process.

[0156] In the nineteenth aspect, either alone or in combination with one or more of the first to eighteenth aspects, the first PRACH parameter set is the same as a data parameter set based at least in part on the subcarrier spacing in a cell associated with the base station, and the second PRACH parameter set is smaller than the data parameter set based at least in part on the subcarrier spacing in the cell associated with the base station.

[0157] although Fig.12 An example block diagram of process 1200 is shown, but in some aspects, process 1200 may include more Fig.12 The blocks depicted in the process 1200 may be more blocks, fewer blocks, different blocks, or blocks arranged differently. Additionally or alternatively, two or more blocks of the process 1200 may be executed in parallel.

[0158] The following provides an overview of some aspects of the disclosure:

[0159] Aspect 1: A wireless communication method performed by a UE, comprising: receiving initial timing advance information from a base station in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the base station; sending a msg3 communication to the base station using the initial timing advance, the initial timing advance being based at least in part on the initial timing advance information; and receiving updated timing advance information from the base station based at least in part on detection of the msg3 communication by the base station, the updated timing advance information resolving a timing advance wrap-around between the UE and the base station.

[0160] Aspect 2: The method according to aspect 1, wherein the initial timing advance information indicates an initial timing advance to be used for msg3 communication within a complete symbol duration, and the complete symbol duration is at least partially based on the subcarrier spacing.

[0161] Aspect 3: The method according to aspect 2, wherein the updated timing advance information includes a non-negative integer value indicating a time to be added to an initial timing advance for msg3 communication based at least in part on the full symbol duration.

[0162] Aspect 4: A method according to any one of Aspects 1 to 3, wherein the base station detects msg3 communication based on multiple timing assumptions, the multiple timing assumptions including an alignment timing assumption based at least in part on an initial timing advance and one or more additional timing assumptions based at least in part on one or more possible values ​​for timing advance wraparound between the UE and the base station.

[0163] Aspect 5: The method according to aspect 4, wherein the base station attempts to detect one or more of the DMRS or PUSCH associated with the msg3 communication based on the multiple timing hypotheses.

[0164] Aspect 6: The method according to any one of Aspects 4 to 5 further includes: sending a timing resolution reference signal to the base station before msg3 communication, wherein the base station attempts to detect msg3 communication based on the multiple timing hypotheses at least in part based on the timing information determined from the timing resolution reference signal.

[0165] Aspect 7: A method according to Aspect 6, wherein the resources allocated to one or more of the timing resolution reference signal or msg3 communication are separated from one or more other uplink signals by one or more symbol gaps in time and by one or more guard resource elements or resource blocks.

[0166] Aspect 8: The method according to any one of aspects 1 to 7, wherein the updated timing advance information is received in a PDCCH or a PDSCH associated with msg4 communication of a four-step RACH procedure.

[0167] Aspect 9: The method according to aspect 8 also includes: sending one or more uplink communications including an acknowledgment of the msg4 communication to the base station based at least in part on the updated timing advance information.

[0168] Aspect 10: A method according to any one of aspects 1 to 9, wherein updated timing advance information is received in a retransmission of msg2 communication based at least in part on the base station failing to detect msg3 communication using initial timing advance.

[0169] Aspect 11: The method according to Aspect 10 also includes: retransmitting msg3 communication to the base station based on the updated timing advance information; and receiving msg4 communication of the four-step RACH process from the base station at least partially based on the base station detecting msg3 communication based on the updated timing advance information.

[0170] Aspect 12: A method according to any one of aspects 10 to 11, wherein the retransmission of the msg2 communication is received during a RAR window monitored by the UE, and the duration of the RAR window is at least partially based on a supported cell size associated with the base station.

[0171] Aspect 13: The method according to any one of aspects 1 to 12, wherein the updated timing advance information is received in a PDCCH including a DCI triggering retransmission of msg3 communication.

[0172] Aspect 14: The method according to aspect 13, wherein the updated timing advance information is indicated in a HARQ process identifier field of the DCI that triggers the retransmission of the msg3 communication.

[0173] Aspect 15: The method according to any one of aspects 13 to 14, wherein the updated timing advance information is indicated by an entry in a TDRA table.

[0174] Aspect 16: A method according to any one of Aspects 1 to 15, wherein the initial timing advance information includes multiple timing advance commands and multiple resource allocations for msg3 communication, wherein the msg3 communication is sent in multiple repetitions at least in part based on the multiple timing advance commands and multiple resource allocations for msg3 communication.

[0175] Aspect 17: The method according to aspect 16, wherein the updated timing advance information is explicitly indicated in the msg4 communication of the four-step RACH procedure based at least in part on the multiple repetitions of the msg3 communication.

[0176] Aspect 18: The method according to any one of Aspects 16 to 17, wherein the updated timing advance information is implicitly indicated by a msg4 communication of a four-step RACH procedure received as a reply to one of the multiple repetitions of the msg3 communication.

[0177] Aspect 19: The method according to any one of Aspects 1 to 18 further includes: receiving random access configuration information from a base station, the random access configuration information including a first PRACH parameter set for a two-step RACH process and a second PRACH parameter set for a four-step RACH process.

[0178] Aspect 20: A method according to Aspect 19, wherein the first PRACH parameter set is the same as a data parameter set based at least in part on the subcarrier spacing in a cell associated with the base station, and wherein the second PRACH parameter set is smaller than the data parameter set based at least in part on the subcarrier spacing in the cell associated with the base station.

[0179] Aspect 21: A wireless communication method performed by a base station, comprising: sending initial timing advance information to a UE in a msg2 communication of a four-step RACH process based at least in part on a subcarrier spacing in a cell associated with the base station; receiving a msg3 communication using an initial timing advance from the UE, the initial timing advance being based at least in part on the initial timing advance information; and sending updated timing advance information to the UE based at least in part on the base station detecting the msg3 communication, the updated timing advance information resolving a timing advance wraparound between the UE and the base station.

[0180] Aspect 22: The method according to aspect 21, wherein the initial timing advance information indicates an initial timing advance to be used for msg3 communication within a complete symbol duration, and the complete symbol duration is at least partially based on the subcarrier spacing.

[0181] Aspect 23: The method according to aspect 22, wherein the updated timing advance information includes a non-negative integer value indicating a time to be added to an initial timing advance for msg3 communication based at least in part on the full symbol duration.

[0182] Aspect 24: The method according to any one of Aspects 21 to 23 further includes: detecting msg3 communication based on multiple timing assumptions, the multiple timing assumptions including an alignment timing assumption based at least in part on an initial timing advance and one or more additional timing assumptions based at least in part on one or more possible values ​​for timing advance wraparound between the UE and the base station.

[0183] Aspect 25: The method according to aspect 24 further comprises: attempting to detect one or more of DMRS or PUSCH associated with msg3 communication based on the multiple timing hypotheses.

[0184] Aspect 26: The method according to any one of Aspects 24 to 25 further includes: receiving a timing resolution reference signal from the UE before msg3 communication; and attempting to detect msg3 communication according to multiple timing hypotheses based at least in part on the timing information determined from the timing resolution reference signal.

[0185] Aspect 27: A method according to Aspect 26, wherein the resources allocated to one or more of the timing resolution reference signal or msg3 communication are separated from one or more other uplink signals by one or more symbol gaps in time and by one or more guard resource elements or resource blocks.

[0186] Aspect 28: A method according to any one of aspects 21 to 27, wherein the updated timing advance information is sent in a PDCCH or PDSCH channel associated with msg4 communication of a four-step RACH procedure.

[0187] Aspect 29: The method according to aspect 28 also includes: receiving one or more uplink communications from the UE based at least in part on the updated timing advance information, the one or more uplink communications including an acknowledgment of the msg4 communication.

[0188] Aspect 30: A method according to any of aspects 21-29, wherein updated timing advance information is sent in a retransmission of msg2 communication based at least in part on failure to detect msg3 communication using the initial timing advance.

[0189] Aspect 31: The method according to Aspect 30 also includes: receiving a retransmission of msg3 communication based on updated timing advance information from the UE; and sending msg4 communication of the four-step RACH process to the UE based at least in part on detecting the retransmission of msg3 communication based on updated timing advance information.

[0190] Aspect 32: A method according to any one of aspects 30 to 31, wherein the retransmission of the msg2 communication is sent during a RAR window monitored by the UE, the duration of the RAR window being based at least in part on a supported cell size associated with the base station.

[0191] Aspect 33: The method according to any one of aspects 21 to 32, wherein the updated timing advance information is sent in a PDCCH including a DCI triggering retransmission of msg3 communication.

[0192] Aspect 34: The method according to aspect 33, wherein the updated timing advance information is indicated in the HARQ process identifier field of the DCI that triggers the retransmission of the msg3 communication.

[0193] Aspect 35: The method according to any one of Aspects 33 to 34, wherein the updated timing advance information is indicated by an entry in a TDRA table.

[0194] Aspect 36: A method according to any one of Aspects 21 to 35, wherein the initial timing advance information includes multiple timing advance commands and multiple resource allocations for msg3 communication, wherein the msg3 communication is received in multiple repetitions at least in part based on the multiple timing advance commands and the multiple resource allocations for msg3 communication.

[0195] Aspect 37: The method according to aspect 36, wherein the updated timing advance information is explicitly indicated in the msg4 communication of the four-step RACH procedure based at least in part on the multiple repetitions of the msg3 communication.

[0196] Aspect 38: A method according to any one of aspects 36 to 37, wherein the updated timing advance information is implicitly indicated by a msg4 communication of a four-step RACH procedure sent as a reply to one of the multiple repetitions of the msg3 communication.

[0197] Aspect 39: The method according to any one of Aspects 21 to 38 further includes: sending random access configuration information to the UE, the random access configuration information including a first PRACH parameter set for a two-step RACH process and a second PRACH parameter set for a four-step RACH process.

[0198] Aspect 40: A method according to Aspect 39, wherein the first PRACH parameter set is the same as a data parameter set based at least in part on the subcarrier spacing in a cell associated with the base station, and wherein the second PRACH parameter set is smaller than the data parameter set based at least in part on the subcarrier spacing in the cell associated with the base station.

[0199] Aspect 41: An apparatus for wireless communication at a device, comprising: a processor; a memory connected to the processor; and instructions stored in the memory and executable by the processor to enable the apparatus to perform one or more methods of Aspects 1 to 20.

[0200] Aspect 42: A device for wireless communication, comprising: a memory; and one or more processors connected to the memory, the memory and the one or more processors being configured to execute the method of one or more aspects of Aspect 1 to Aspect 20.

[0201] Aspect 43: An apparatus for wireless communication, comprising at least one component for performing the method of one or more aspects of Aspect 1 to Aspect 20.

[0202] Aspect 44: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more aspects of aspects 1 to 20.

[0203] Aspect 45: A non-transitory computer-readable medium storing an instruction set for wireless communication, the instruction set comprising one or more instructions which, when executed by one or more processors of a device, causes the device to perform the method of one or more aspects of Aspect 1 to Aspect 20.

[0204] Aspect 46: An apparatus for wireless communication at a device, comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to enable the apparatus to perform one or more methods of Aspects 21 to 40.

[0205] Aspect 47: A device for wireless communication, comprising: a memory; and one or more processors coupled to the memory, the memory and the one or more processors being configured to execute the method of one or more aspects of Aspect 21 to Aspect 40.

[0206] Aspect 48: An apparatus for wireless communication, comprising at least one component for performing the method of one or more aspects of Aspect 21 to Aspect 40.

[0207] Aspect 49: A non-transitory computer-readable medium storing a code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more aspects of Aspect 21 to Aspect 40.

[0208] Aspect 50: A non-transitory computer-readable medium storing an instruction set for wireless communication, wherein the instruction set includes one or more instructions, which, when executed by one or more processors of a device, causes the device to perform one or more methods of Aspects 21 to 40.

[0209] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of these aspects.

[0210] As used herein, the term "component" is intended to be broadly interpreted as a combination of hardware and / or hardware and software. In other examples, whether referred to as software, firmware, middleware, microcode, hardware description language or other, "software" should be broadly interpreted as representing instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, processes and / or functions. As used herein, the processor is implemented in a combination of hardware and / or hardware and software. It is obvious that the system and / or method described herein can be implemented with a combination of hardware and / or hardware and software in different forms. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit these aspects. Therefore, the operation and behavior of the system and / or method are described herein without reference to a specific software code-it should be understood that, based at least in part on the description herein, software and hardware can be designed to implement the system and / or method.

[0211] As used herein, satisfying a threshold may refer to a value greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0212] Even if a specific combination of features is described in the claims and / or the specification, these combinations are not intended to limit the disclosure of the various aspects. In fact, many of these features can be combined in ways that are not specifically described in the claims and / or not disclosed in the specification. Although each dependent claim listed below may only directly depend on one claim, the disclosure of each aspect includes each dependent claim combined with each other claim in the claim set. As used herein, the phrase "at least one" in the list of items refers to any combination of these items, including single members. For example, "at least one of a, b or c" is intended to cover a, b, c, ab, ac, bc and abc, as well as any combination of multiples of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc and ccc or any other order of a, b and c).

[0213] Unless explicitly described as such, any element, action or instruction used in this article should not be interpreted as critical or necessary. In addition, as used herein, the articles "one" and "an" are intended to include one or more items, and can be used interchangeably with "one or more". In addition, as used herein, the article "said" is intended to include one or more items related to the article "said", and can be used interchangeably with "said one or more". In addition, as used herein, the terms "set" and "group" are intended to include one or more items (for example, a combination of related items, unrelated items, or related items and unrelated items), and can be used interchangeably with "one or more". In the case of only referring to one item, the phrase "only one" or similar language is used. In addition, as used herein, the term "having" etc. is intended to be an open term. In addition, unless otherwise clearly stated, the phrase "based on" means "based at least in part". In addition, as used herein, unless otherwise clearly stated (for example, if used in combination with "any" or "only one"), the term "or" is intended to be inclusive when used in a series, and can be used interchangeably with "and / or".

Claims

1. A method of wireless communication performed by a user equipment UE, comprising: receiving initial timing advance information from a network entity in a msg2 communication of a four-step random access channel (RACH) procedure based at least in part on a subcarrier spacing in a cell associated with the network entity; sending a msg3 communication to the network entity using an initial timing advance, the initial timing advance being based at least in part on the initial timing advance information; as well as Receiving a retransmission of a msg2 communication from the network entity based at least in part on a detection failure corresponding to a msg3 communication, the retransmission of the msg2 communication including updated timing advance information configured for resolving a timing advance value between the UE and the network entity.

2. The method according to claim 1, wherein: The initial timing advance information indicates the initial timing advance to be used for msg3 communication within a complete symbol duration, the complete symbol duration being based at least in part on the subcarrier spacing, and wherein the updated timing advance information comprises a non-negative integer value indicating a time to be added to the initial timing advance for the msg3 communication based at least in part on the complete symbol duration.

3. The method according to claim 1, wherein: The msg3 communication is detected based on multiple timing hypotheses, the multiple timing hypotheses including an alignment timing hypothesis based at least in part on the initial timing advance and one or more additional timing hypotheses based at least in part on one or more possible values ​​of the timing advance value between the UE and the network entity.

4. The method according to claim 3, further comprising: A timing resolution reference signal is sent to the network entity prior to the msg3 communication, wherein the attempt to detect the msg3 communication according to the plurality of timing hypotheses is based at least in part on timing information determined from the timing resolution reference signal.

5. The method according to claim 1, wherein: The updated timing advance information is first updated timing advance information, and the method further includes: The second updated timing advance information is received in a physical downlink control channel or a physical downlink shared channel associated with msg4 communication of the four-step RACH procedure.

6. The method according to claim 1, wherein: Receiving the retransmission of the msg2 communication includes receiving the retransmission of the msg2 communication during a random access response window monitored by the UE, the duration of the random access response window being based at least in part on a supported cell size associated with the network entity.

7. The method according to claim 1, wherein: Receiving the updated timing advance information includes: The updated timing advance information is received in a physical downlink control channel including downlink control information DCI triggering a retransmission of the msg3 communication.

8. The method according to claim 7, wherein: The updated timing advance information is indicated by an entry in a time domain resource allocation table or a hybrid automatic repeat request process identifier field of the DCI that triggers the retransmission of the msg3 communication.

9. The method according to claim 1, wherein: The updated timing advance information is first updated timing advance information, and wherein the initial timing advance information includes multiple timing advance commands and multiple resource allocations for the msg3 communication, wherein sending the msg3 communication includes sending the msg3 communication in multiple repetitions based at least in part on the multiple timing advance commands and the multiple resource allocations for the msg3 communication, and wherein second updated timing advance information is explicitly or implicitly indicated in the msg4 communication of the four-step RACH procedure based at least in part on the multiple repetitions of the msg3 communication.

10. The method according to claim 1, further comprising: random access configuration information is received from the network entity, the random access configuration information comprising a first PRACH parameter set for a two-step RACH procedure and a second PRACH parameter set for a four-step RACH procedure, wherein the first PRACH parameter set is the same as a data parameter set based at least in part on a subcarrier spacing in a cell associated with the network entity, and wherein the second PRACH parameter set is smaller than the data parameter set based at least in part on a subcarrier spacing in a cell associated with the network entity.

11. A method of wireless communication performed by a network entity, comprising: sending initial timing advance information to a user equipment (UE) in a msg2 communication of a four-step random access channel (RACH) procedure based at least in part on a subcarrier spacing in a cell associated with the network entity; sending a retransmission of the msg2 communication to the UE based at least in part on detecting a failure of the msg3 communication, wherein the retransmission of the msg2 communication includes updated timing advance information configured to resolve a timing advance value between the UE and the network entity; and The msg3 communication is received from the UE with a time advance based at least in part on the updated timing advance information.

12. The method according to claim 11, wherein: The initial timing advance information indicates the initial timing advance to be used for the msg3 communication within a complete symbol duration, the complete symbol duration being based at least in part on the subcarrier spacing, and wherein the updated timing advance information comprises a non-negative integer value indicating a time to be added to the initial timing advance for the msg3 communication based at least in part on the complete symbol duration.

13. The method according to claim 11, further comprising: msg3 communications are detected based on a plurality of timing hypotheses including an aligned timing hypothesis based at least in part on the initial timing advance and one or more additional timing hypotheses based at least in part on one or more possible values ​​for the timing advance value between the UE and the network entity.

14. The method according to claim 13, further comprising: Before the msg3 communication, receiving a timing resolution reference signal from the UE; as well as Attempting to detect the msg3 communication according to the plurality of timing hypotheses based at least in part on timing information determined from a timing resolution reference signal.

15. The method according to claim 11, wherein: The updated timing advance information is first updated timing advance information, and the method further includes: The second updated timing advance information is sent in a physical downlink control channel or a physical downlink shared channel associated with msg4 communication of the four-step RACH procedure.

16. The method according to claim 11, wherein: Sending the retransmission of the msg2 communication includes sending the retransmission of the msg2 communication during a random access response window monitored by the UE, the duration of the random access response window being based at least in part on a supported cell size associated with the network entity.

17. The method according to claim 11, wherein: The updated timing advance information is sent in a physical downlink control channel including downlink control information DCI triggering retransmission of the msg3 communication.

18. The method according to claim 17, wherein: The updated timing advance information is indicated by an entry in a time domain resource allocation table or a hybrid automatic repeat request process identifier field of the DCI that triggers the retransmission of the msg3 communication.

19. The method according to claim 11, wherein: The updated timing advance information is first updated timing advance information, and wherein the initial timing advance information includes multiple timing advance commands and multiple resource allocations for the msg3 communication, wherein receiving the msg3 communication includes receiving the msg3 communication in multiple repetitions based at least in part on the multiple timing advance commands and the multiple resource allocations for the msg3 communication, and wherein, based at least in part on the multiple repetitions of the msg3 communication, second updated timing advance information is explicitly or implicitly indicated in the msg4 communication of the four-step RACH procedure.

20. The method according to claim 11, further comprising: Sending random access configuration information to a UE, the random access configuration information comprising a first PRACH parameter set for a two-step RACH procedure and a second PRACH parameter set for a four-step RACH procedure, wherein the first PRACH parameter set is the same as a data parameter set based at least in part on a subcarrier spacing in a cell associated with the network entity, and wherein the second PRACH parameter set is smaller than the data parameter set based at least in part on a subcarrier spacing in a cell associated with the network entity.

21. A user equipment UE for wireless communication, comprising: Memory; and One or more processors, coupled to the memory, the one or more processors configured to cause the UE to: receiving initial timing advance information from a network entity in a msg2 communication of a four-step random access channel procedure based at least in part on a subcarrier spacing in a cell associated with the network entity; sending a msg3 communication to the network entity using an initial timing advance, the initial timing advance being based at least in part on the initial timing advance information; and Receiving a retransmission of the msg2 communication from the network entity based at least in part on a detection failure corresponding to the msg3 communication, the retransmission of the msg2 communication including updated timing advance information configured for resolving a timing advance value between the UE and the network entity.

22. The UE according to claim 21, wherein: The initial timing advance information indicates the initial timing advance to be used for msg3 communication within a complete symbol duration, the complete symbol duration being based at least in part on the subcarrier spacing, and wherein the updated timing advance information comprises a non-negative integer value indicating a time to be added to the initial timing advance for the msg3 communication based at least in part on the complete symbol duration.

23. The UE according to claim 21, wherein: The msg3 communication is detected based on a plurality of timing hypotheses including an aligned timing hypothesis based at least in part on the initial timing advance and one or more additional timing hypotheses based at least in part on one or more possible values ​​of the timing advance value between the UE and the network entity.

24. The UE according to claim 23, wherein: The one or more processors are further configured to cause the UE to: A timing resolution reference signal is sent to the network entity prior to the msg3 communication, wherein the attempt to detect the msg3 communication according to a plurality of timing hypotheses is based at least in part on timing information determined from the timing resolution reference signal.

25. The UE according to claim 21, wherein: The updated timing advance information is first updated timing advance information, and wherein the one or more processors are further configured to cause the UE to receive second updated timing advance information in a physical downlink control channel or a physical downlink shared channel associated with msg4 communication of a four-step RACH procedure.

26. The UE according to claim 21, wherein: To receive a retransmission of the msg2 communication, the one or more processors are configured to cause the UE to receive the retransmission of the msg2 communication during a random access response window monitored by the UE, the duration of the random access response window being based at least in part on a supported cell size associated with the network entity.

27. The UE according to claim 21, wherein: To receive the updated timing advance information, the one or more processors are configured to cause the UE to receive the updated timing advance information in a physical downlink control channel including downlink control information DCI triggering retransmission of msg3 communication.

28. The UE according to claim 27, wherein: The updated timing advance information is indicated by an entry in a time domain resource allocation table or a hybrid automatic repeat request process identifier field of the DCI that triggers the retransmission of the msg3 communication.

29. The UE according to claim 21, wherein: The updated timing advance information is first updated timing advance information, wherein the initial timing advance information includes multiple timing advance commands and multiple resource allocations for the msg3 communication, wherein, to send the msg3 communication, the one or more processors are configured to enable the UE to send the msg3 communication in multiple repetitions at least partially based on the multiple timing advance commands and the multiple resource allocations for the msg3 communication, and wherein, at least partially based on the multiple repetitions of the msg3 communication, the second updated timing advance information is explicitly or implicitly indicated in the msg4 communication of the four-step RACH process.

30. The UE according to claim 21, wherein: The one or more processors are further configured to cause the UE to: random access configuration information is received from the network entity, the random access configuration information comprising a first PRACH parameter set for a two-step RACH procedure and a second PRACH parameter set for the four-step RACH procedure, wherein the first PRACH parameter set is the same as a data parameter set based at least in part on a subcarrier spacing in a cell associated with the network entity, and wherein the second PRACH parameter set is smaller than the data parameter set based at least in part on a subcarrier spacing in a cell associated with the network entity.

31. A network entity for wireless communication, comprising: Memory; and One or more processors, coupled to the memory, the one or more processors configured to cause the network entity to: sending initial timing advance information to a user equipment (UE) in a msg2 communication of a four-step random access channel procedure (RACH) based at least in part on a subcarrier spacing in a cell associated with the network entity; sending a retransmission of the msg2 communication to the UE based at least in part on detecting a failure of the msg3 communication, the retransmission of the msg2 communication including updated timing advance information, the updated timing advance information configured to resolve a timing advance value between the UE and the network entity; as well as A msg3 communication is received from the UE having a timing advance based at least in part on the updated timing advance information.

32. The network entity according to claim 31, wherein: The initial timing advance information indicates the initial timing advance to be used for msg3 communication within a complete symbol duration, the complete symbol duration being based at least in part on the subcarrier spacing, and wherein the updated timing advance information comprises a non-negative integer value indicating a time to be added to the initial timing advance for the msg3 communication based at least in part on the complete symbol duration.

33. The network entity according to claim 31, wherein: The one or more processors are further configured to cause the network entity to: msg3 communications are detected based on a plurality of timing hypotheses including an aligned timing hypothesis based at least in part on the initial timing advance and one or more additional timing hypotheses based at least in part on one or more possible values ​​for the timing advance value between the UE and the network entity.

34. The network entity according to claim 33, wherein: The one or more processors are further configured to cause the network entity to: receiving a timing resolution reference signal from the UE before communicating the msg3; and Attempting to detect the msg3 communication based on the plurality of timing hypotheses based at least in part on timing information determined from the timing resolution reference signal.

35. The network entity according to claim 31, wherein: The updated timing advance information is first updated timing advance information, and wherein the one or more processors are further configured to cause the network entity to send second updated timing advance information in a physical downlink control channel or a physical downlink shared channel associated with msg4 communication of a four-step RACH procedure.

36. The network entity according to claim 31, wherein: To send a retransmission of the msg2 communication, the one or more processors are configured to cause the network entity to send a retransmission of the msg2 communication during a random access response window monitored by the UE, the duration of the random access response window being based at least in part on a supported cell size associated with the network entity.

37. The network entity according to claim 31, wherein: To send the updated timing advance information, the one or more processors are configured to cause the network entity to send the updated timing advance information in a physical downlink control channel including downlink control information DCI triggering retransmission of the msg3 communication.

38. The network entity according to claim 37, wherein: The updated timing advance information is indicated by an entry in a time domain resource allocation table or a hybrid automatic repeat request process identifier field of the DCI that triggers the retransmission of the msg3 communication.

39. The network entity according to claim 31, wherein: The updated timing advance information is first updated timing advance information, and wherein the initial timing advance information includes multiple timing advance commands and multiple resource allocations for the msg3 communication, wherein, to receive the msg3 communication, the one or more processors are configured to enable the network entity to receive the msg3 communication in multiple repetitions based at least in part on the multiple timing advance commands and the multiple resource allocations for the msg3 communication, wherein the second updated timing advance information is explicitly or implicitly indicated in the msg4 communication of the four-step RACH procedure based at least in part on the multiple repetitions of the msg3 communication.

40. The network entity according to claim 31, wherein: The one or more processors are further configured to cause the network entity to: Sending random access configuration information to the UE, the random access configuration information comprising a first PRACH parameter set for a two-step RACH procedure and a second PRACH parameter set for a four-step RACH procedure, wherein the first PRACH parameter set is the same as a data parameter set based at least in part on a subcarrier spacing in a cell associated with the network entity, and wherein the second PRACH parameter set is smaller than the data parameter set based at least in part on a subcarrier spacing in a cell associated with the network entity.

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