Alternative two-step RACH procedure

Abstract

Various aspects of the present disclosure generally relate to wireless communications. In some aspects, a user equipment may perform an initial two-step random access channel (RACH) attempt by sending an initial request message of an initial RACH procedure to a base station; and perform additional RACH attempts using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to the initial request message of the two-step RACH procedure was not received during an initial random access response window. Many other aspects are provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 005,053, filed on April 3, 2020, entitled “ALTERNATIVE TWO-STEP RACH PROCEDURE,” and U.S. Non-Provisional Patent Application No. 17 / 190,723, filed on March 3, 2021, entitled “ALTERNATIVE TWO-STEP RACH PROCEDURE,” which are expressly incorporated herein by reference. Technical Field

[0003] Aspects of the present disclosure relate generally to wireless communications and techniques and apparatus for an alternative two-step random access channel procedure. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication services, such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies that are capable of supporting 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 equipment (UEs). A UE may communicate with a BS via a downlink and an uplink. A downlink (or forward link) refers to a communication link from a BS to a UE, and an uplink (or reverse link) refers to a communication link from a UE to a BS. As will be described in more detail herein, a BS may be referred to as a Node B, gNB, access point (AP), radio head, transmit receive point (TRP), new radio (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 equipment to communicate at municipal, national, regional and even global levels. NR (also known as 5G) is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR aims to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and using orthogonal frequency division multiplexing (PFDM) on the downlink (DL) and 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 increase, further improvements in LTE, NR and other wireless access technologies remain useful. Summary of the invention

[0007] In some aspects, a wireless communication method performed by a user equipment may include: performing an initial two-step random access channel (RACH) attempt by sending an initial request message for an initial RACH process to a base station; and performing additional RACH attempts using an alternative two-step RACH process based at least in part on determining that an initial response message corresponding to the initial request message for the two-step RACH process was not received during an initial random access response (RAR) window.

[0008] In some aspects, a wireless communication method performed by a base station may include: receiving an initial request message for an initial two-step RACH procedure from a UE, wherein the initial request message corresponds to an initial RACH attempt; and receiving an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed at least in part based on the UE not receiving an initial response message corresponding to the initial request message during an initial RAR window.

[0009] In some aspects, a UE for wireless communication may include: a memory; and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: perform an initial RACH attempt by sending an initial request message of an initial two-step RACH procedure to a base station; and perform additional RACH attempts using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to the initial request message of the two-step RACH procedure was not received during an initial RAR window.

[0010] In some aspects, a base station for wireless communication may include: a memory; and one or more processors coupled to the memory. The memory and the one or more processors are configured to: receive an initial request message for an initial two-step RACH procedure from a UE, wherein the initial request message corresponds to an initial RACH attempt; and receive an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed at least in part based on the UE not receiving an initial response message corresponding to the initial request message during an initial RAR window.

[0011] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to perform an initial RACH attempt by sending an initial request message of an initial two-step RACH procedure to a base station; and perform additional RACH attempts using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to the initial request message of the two-step RACH procedure was not received during an initial RAR window.

[0012] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a base station, may cause the one or more processors to receive an initial request message for an initial two-step RACH procedure from a UE, wherein the initial request message corresponds to an initial RACH attempt; and receive an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed based at least in part on the UE not receiving an initial response message corresponding to the initial request message during an initial RAR window.

[0013] In some aspects, an apparatus for wireless communication may include: a unit for performing an initial RACH attempt by sending an initial request message for an initial two-step RACH procedure to a base station; and a unit for performing additional RACH attempts using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to the initial request message for the two-step RACH procedure was not received during an initial RAR window.

[0014] In some aspects, an apparatus for wireless communication may include: a unit for receiving an initial request message for an initial two-step RACH procedure from a UE, wherein the initial request message corresponds to an initial RACH attempt; and a unit for receiving an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed at least in part based on the UE not receiving an initial response message corresponding to the initial request message during an initial RAR window.

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

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

[0017] Although various aspects are described in the present disclosure by the description of some examples, it will be understood by those skilled in the art that these aspects can be implemented in many different arrangements and scenarios. The technology described herein can be implemented using different platform types, devices, systems, shapes, sizes and / or packaging arrangements. For example, some aspects can be implemented via integrated chip embodiments or other devices based on non-module components (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing equipment, medical devices, or artificial intelligence devices). Various aspects can be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, or system-level components. The device in combination with the various aspects and features described may include additional components and features for implementing and practicing the various aspects claimed and described. For example, the transmission and reception of wireless signals may include multiple components (e.g., hardware components, including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders, or summers) for analog and digital purposes. The various aspects described herein are intended to be practiced with various devices, components, systems, distributed devices, or end-user devices of different sizes, shapes, and configurations. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order that the above-mentioned features of the present disclosure may be understood in detail, a more specific description briefly summarized above may be obtained by reference to various aspects, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate certain typical aspects of the present disclosure and are therefore not to be considered as limiting the scope thereof, as the description may admit of other equally valid aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0019] Figure 1 is a diagram illustrating an example of a wireless network according to the present disclosure.

[0020] 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.

[0021] Figure 3 is a diagram illustrating an exemplary two-step random access channel (RACH) procedure according to the present disclosure.

[0022] Figure 4 is a diagram illustrating an exemplary random access message including a preamble and a payload according to the present disclosure.

[0023] Figure 5 is a diagram illustrating an example of an alternative two-step RACH procedure according to the present disclosure.

[0024] Figure 6 is a diagram illustrating an exemplary process performed, for example, by a user equipment according to the present disclosure.

[0025] Figure 7 is a diagram illustrating an exemplary 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 to make the present disclosure thorough and complete, and will fully convey the scope of the present disclosure 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 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 practice an apparatus or method. In addition, the scope of the present disclosure is intended to cover such an apparatus or method, which is practiced using other structures, functions, or structures and functions of various aspects of the disclosure set forth herein in addition to or different from those set forth herein. It should be understood that any aspect of the 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 following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using hardware, software, or a combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0028] It should be noted that while various aspects may be described using terminology typically 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 diagram showing an example of a wireless network 100 according to the present disclosure. The wireless network 100 may be or may include elements of a 5G (NR) network and / or an LTE network, among other examples. 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., a radius of several kilometers) and may allow unrestricted access to UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access to UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access to 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", "Node B", "5G NB", and "cell" may be used interchangeably herein.

[0031] In some aspects, the cells may not necessarily be 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 system 100 via various types of backhaul interfaces (e.g., 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 is capable of relaying transmissions for other UEs. Figure 1 In the illustrated example, a relay BS 110d may communicate with a macro BS 110a and a UE 120d to facilitate communication between the BS 110a and the UE 120d. A relay BS may also be referred to as a relay station, a relay base station, a relay, or the like.

[0033] The wireless network 100 may be a heterogeneous network including different types of BSs, such as macro BSs, pico BSs, femto BSs, relay BSs, 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 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 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, for example, via a wireless or wired backhaul.

[0035] UE 120 (e.g., 120a, 120b, 120c) can be dispersed throughout the wireless network 100, and each UE can be fixed or mobile. UE can also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. UE can be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, a biometric sensor / device, a wearable device (smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device or a satellite radio), a vehicle component or sensor, a smart meter / sensor, an industrial manufacturing device, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium.

[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. A wireless node may provide a connection to, for example, a network or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered as Internet of Things (IoT) devices, 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 contained within a housing that houses components (e.g., processor components and / or memory components) of UE 120. In some aspects, a processor component and a memory component may be coupled together. For example, a processor component (e.g., one or more processors) and a memory component (e.g., a memory) may be operatively coupled, communicatively coupled, electronically coupled and / or electrically coupled.

[0037] Generally, any number of communication systems 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 wireless 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 implementations, 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 for communicating 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 other operations described elsewhere herein as being performed by base station 110.

[0039] The devices of the wireless network 100 can communicate using an electromagnetic spectrum, which can be subdivided into various categories, frequency bands, channels, etc. based on frequency or wavelength. For example, the devices of the wireless network 100 can communicate using an operating frequency band having a first frequency range (FR1) spanning from 410 MHz to 7.125 GHz, and / or can communicate using an operating frequency band having a second frequency range (FR2) spanning from 24.25 GHz to 52.6 GHz. Frequencies between FR1 and FR2 are sometimes referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as a "below 6 GHz" band. Similarly, FR2 is often referred to as a "millimeter wave" band, but it is different from the extremely high frequency (EHF) band (30 GHz-300 GHz) determined by the International Telecommunication Union (ITU) as a "millimeter wave" band. Therefore, unless otherwise expressly stated, it should be understood that the term "below 6 GHz" and the like when used herein can be widely used to represent frequencies less than 6 GHz, frequencies within FR1, and / or mid-band frequencies (e.g., greater than 7.125 GHz). Similarly, unless otherwise expressly stated, it should be understood that the term "millimeter wave" and the like, when used herein, can broadly refer to frequencies within the EHF band, frequencies within FR2, and / or mid-band frequencies (e.g., less than 24.25 GHz). It is contemplated that the frequencies contained within FR1 and FR2 may be modified, and the techniques described herein are applicable to those modified frequency ranges.

[0040] As mentioned above, providing 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 in accordance with 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 from the data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) 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, etc.), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., a cell-specific reference signal (CRS) or a demodulation reference signal (DMRS)) and synchronization signals (e.g., a primary synchronization signal (PSS) and a secondary synchronization signal (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 (MODs) 232a through 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may also process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 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 also process the input samples (e.g., for OFDM, etc.) 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 when 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. The channel processor may 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, among other examples. In some aspects, one or more components of UE 120 may be contained within 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] Antennas (e.g., antennas 234a to 234t and / or antennas 252a to 252r) may include or be contained in one or more antenna panels, antenna groups, antenna element sets, and / or antenna arrays, etc. Antenna panels, antenna groups, antenna element sets, and / or antenna arrays may include one or more antenna elements. Antenna panels, antenna groups, antenna element sets, and / or antenna arrays may include coplanar antenna element sets and / or non-coplanar antenna element sets. Antenna panels, antenna groups, antenna element sets, and / or antenna arrays may include antenna elements within a single housing and / or antenna elements within multiple housings. Antenna panels, antenna groups, antenna element sets, and / or antenna arrays may include one or more antenna elements coupled to one or more transmit and / or receive components, such as Figure 2 One or more components of a

[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, CQI, etc.) 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 antennas 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 used by a processor (e.g., controller / processor 240) and memory 242 to perform aspects of any of the methods described herein (e.g., reference 200 to FIG. 1 ). Figure 2-7 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 to schedule the UE 120 for downlink and / or uplink communications. 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 may include a transceiver. The transceiver may include any combination of antennas 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 used by a processor (e.g., controller / processor 240) and memory 242 to perform aspects of any of the methods described herein (e.g., reference 200 to FIG. 1 ). Figure 2-7 described).

[0048] The controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component of the may perform one or more techniques associated with the alternative two-step random access channel (RACH) procedure, as described in more detail elsewhere herein. 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 may perform or direct e.g. Figure 6 The operation of process 600, Figure 7 10 and / or other processes described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and / or program code) for wireless communication. For example, when executed by one or more processors of base station 110 and / or UE 120 (e.g., directly or after compilation, conversion, and / or interpretation), the one or more instructions may cause one or more processors, UE 120, and / or base station 110 to perform or direct, for example, Figure 6 The process of 600 Figure 7 In some aspects, executing instructions may include running instructions, converting instructions, compiling instructions, and / or interpreting instructions, among other examples.

[0049] In some aspects, UE 120 may include means for performing an initial RACH attempt by sending an initial request message for an initial two-step RACH procedure to a base station; means for performing additional RACH attempts using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to the initial request message for the two-step RACH procedure was not received during an initial random access response (RAR) window, and the like. In some aspects, such means may include combining 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, the base station 110 may include means for receiving an initial request message for an initial two-step RACH procedure from the UE, wherein the initial request message corresponds to an initial RACH attempt; means for receiving an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed based at least in part on the UE not receiving an initial response message corresponding to the initial request message during the initial RAR window; and so on. In some aspects, such means may include in conjunction with Figure 2 One or more components of base station 110 are depicted, such as antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, and the like.

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

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

[0053] Figure 3 is a diagram illustrating an exemplary two-step RACH procedure 300 according to the present disclosure. Figure 3 As shown, base station 110 and UE 120 may communicate with each other to perform a two-step RACH procedure.

[0054] In a first operation 305, the base station 110 may send and the UE 120 may receive one or more synchronization signal blocks (SSBs), system information blocks (SIBs), reference signals (RSs), radio resource control (RRC) signaling messages, etc. For example, as described in further detail elsewhere herein, the SSBs, SIBs, RSs, RRC signaling messages, etc. may include information related to one or more RACH opportunity (RO) configurations, such as information related to one or more ordered preamble resources. In a second operation 310, the UE 120 may perform downlink (DL) synchronization (e.g., using one or more SSBs), decode system information (SI) and / or RRC configuration information contained in one or more SIBs, perform one or more measurements on the RS, etc. Based at least in part on performing the second operation 310, the UE 120 may determine one or more parameters for sending a random access message (RAM) in a two-step RACH procedure. For example, UE 120 may determine one or more physical random access channel (PRACH) transmission parameters for sending the RAM, may determine one or more parameters for generating a preamble for the RAM, may identify one or more uplink resources on which to send the RAM, and so on.

[0055] In the third operation 315, the UE 120 may send a RAM preamble. In the fourth operation 320, the UE 120 may send a RAM payload. As shown, the UE 120 may send a RAM preamble and a RAM payload as part of the first step of the two-step RACH process. RAM is sometimes referred to as message A, msgA, uplink message, first (or initial) message in a two-step RACH process, request message, etc. The RAM preamble is sometimes referred to as message A preamble, msgA preamble, preamble, etc. The RAM payload is sometimes referred to as message A payload, msgA payload, payload, etc. In some aspects, the RAM may include some or all of the contents of message 1 (msg1) and message 3 (msg3) of the four-step RACH process. For example, the RAM preamble may include some or all of the contents of message 1 (e.g., RACH preamble), and the RAM payload may include some or all of the contents of message 3. For example, in some aspects, the RAM payload may include an identifier associated with the UE 120, uplink control information, medium access control (MAC) layer control elements (e.g., power headroom report, buffer status report, beam failure report, channel status report, etc.), user plane data, control plane data, etc. Further, in some aspects, the msgA preamble and the msgA payload may be time division multiplexed (TDM) with each other, whereby the msgA preamble and the msgA payload may be transmitted in separate symbols based at least in part on a time division multiplexing configuration.

[0056] In a fourth operation 325, the base station 110 may receive a RAM preamble sent by the UE 120. If the base station 110 successfully receives and decodes the RAM preamble, the base station 110 may receive and decode the RAM payload. In a fifth operation 330, the base station 110 may send a random access response (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. The RAR message is sometimes referred to as message B, msgB, the second message in the two-step RACH process, a response message, etc. 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 RACH preamble identifier, a detected UE identifier, a time advance value, contention resolution information, etc. In some aspects, the RAR message may include a first portion sent via a physical downlink control channel (PDCCH) (e.g., to include some or all of the contents of msg2 of the four-step RACH process) and a second portion sent via a physical downlink shared channel (PDSCH) (e.g., to include some or all of the contents of msg4 of the four-step RACH process). In some aspects, based on whether UE 120 successfully receives and decodes the RAR message, the UE may send hybrid automatic repeat (HARQ) feedback (e.g., an acknowledgment (ACK) indicating that the RAR message has been successfully received and decoded, or a negative acknowledgment (NACK) indicating that the RAR message has not been successfully received and decoded) to base station 110 via a physical uplink control channel (PUCCH).

[0057] As mentioned above, providing Figure 3 As an example. Other examples may be related to Figure 3 Different than described.

[0058] Figure 4 4 is a diagram showing an exemplary random access message 400 including a preamble and a payload according to the present disclosure. As shown, the random access message 400 of the two-step RACH procedure may include a preamble and a payload, as described above. The preamble may include a PRACH preamble signal and a first guard time (shown as GT#1, with a duration of T G The payload may include a demodulation reference signal (DMRS) and / or a physical uplink shared channel (PUSCH) communication, and a second guard time (shown as GT#2, with a duration of T G ).like Figure 4 As further shown, the transmission of the preamble and the transmission of the payload may be separated by a transmission protection time (shown as TxG, with a duration of T g ) separated in time.

[0059] like Figure 4As further shown and indicated by reference numeral 405, the UE may select an RO and a PRACH sequence for transmitting the msgA preamble. For example, as described in further detail elsewhere herein, the UE may select the RO and the PRACH sequence based at least in part on one or more shared ROs configured by the base station for a two-step RACH procedure and a four-step RACH procedure, one or more dedicated ROs configured by the base station for a two-step RACH procedure, and the like. Furthermore, in some aspects, the base station may configure an ordered set of preamble resources on the shared and / or dedicated ROs, and the UE may select the PRACH sequence based at least in part on the ordered set of preamble resources. Figure 4 As further shown and indicated by reference numeral 410, the UE may select a set of DMRS resources and a PUSCH opportunity for transmitting the msgA payload. For example, as described in further detail herein, the UE may select a set of DMRS resources and / or a PUSCH opportunity based at least in part on a preamble to PUSCH resource unit (PRU) mapping. Additionally, in some aspects, the UE may select multiple PRUs to support frequency hopping, repetition of a PUSCH portion of the msgA payload, and the like.

[0060] As mentioned above, providing Figure 4 As an example. Other examples may be related to Figure 4 Different than described.

[0061] The request message (msgA) and the response message (msgB) may be the bottleneck of mmWave 5G system coverage. Preamble repetition and / or using different preamble formats may help increase msgA coverage and / or msgB coverage by facilitating base station beam refinement, but usually consumes unnecessary resources. Response message (msgB PDCCH) repetition may help increase msgB coverage, but may also consume unnecessary resources.

[0062] Various aspects of the techniques and apparatus described herein can facilitate enhanced coverage without unnecessarily increasing resource consumption. In some aspects, the UE 120 can perform additional RACH attempts using a two-step RACH process based at least on determining that an initial response message corresponding to an initial request message has not been received. Additional RACH attempts can be performed using an alternative RACH process that is different from the process used to perform the initial RACH attempt. In some aspects, the alternative RACH process can use an alternative transmission method of the msgA preamble, an alternative mapping between RACH opportunities (RO) and PUSCH resources, an alternative method for monitoring and receiving response messages, an alternative RAR window, an alternative size of the DCI carried by the msgB PDCCH, an alternative interpretation of the DCI content carried by the msgB PDCCH, and the like.

[0063] In some aspects, an alternative transmission method for the msgA preamble may include sending multiple sequences across multiple ROs, wherein the multiple ROs are used as virtual ROs for the alternative msgA preamble. The sequence may be a single repeated sequence, a plurality of linked sequences, etc. In this way, the base station may facilitate increasing the coverage of the RACH process without using unnecessary resources. In some aspects, the alternative mapping between RO and PUSCH resources may include mapping more than one RO to a PUSCH resource set. In this way, RACH coverage may be increased without using additional PUSCH resources. In some aspects, an alternative method for monitoring and receiving a response message may include soft combining multiple monitoring opportunities before decoding and blind detection. In this way, msg B may be transmitted over multiple monitoring opportunities to increase coverage. In some aspects, alternative RAR windows and / or DCI transmissions may be used to increase RACH coverage for a specific UE, which invokes an alternative RACH process by using an alternative msg A transmission. In this way, RACH coverage for a specific UE may be increased without allocating additional resources to all UEs.

[0064] Figure 5 is a diagram illustrating an example of an alternative two-step RACH procedure according to the present disclosure. As shown, UE 120 and base station 110 may communicate with each other.

[0065] As indicated by reference numeral 505, UE 120 may perform an initial RACH attempt by sending an initial request message of an initial two-step RACH procedure to base station 110. As indicated by reference numeral 510, UE 120 may determine that an initial response message corresponding to the initial request message of the two-step RACH procedure is not received during the initial RAR window.

[0066] As indicated by reference numeral 515, the UE 120 may perform an additional RACH attempt using an alternative two-step RACH procedure by sending an additional request message to the base station 110. In some aspects, the UE 120 may perform an additional RACH attempt based at least in part on determining that an initial response message corresponding to the initial request message of the two-step RACH procedure was not received during the initial RAR window. In some aspects, the UE 120 may obtain one or more measurements associated with the signal and perform an additional RACH attempt based at least in part on the one or more measurements. In some aspects, the one or more measurements may include a reference signal received power (RSRP) based on a synchronization signal block (SSB). The UE may perform an additional RACH attempt based at least in part on determining that the RSRP based on the SSB satisfies a threshold.

[0067] In some aspects, sending the initial request message may include sending an initial request message preamble according to an initial transmission procedure, and performing the alternative two-step RACH procedure may include sending at least one additional request message preamble according to an additional transmission procedure. The additional transmission procedure may be different from the initial transmission procedure. In some aspects, the additional transmission procedure may include a coverage enhancement transmission procedure.

[0068] In some aspects, the initial transmission process may be performed using a first transmission power, and the additional transmission process may be performed using a second transmission power that is higher than the first transmission power. In some aspects, the initial transmission process may be performed using a first preamble sequence subset of the set of preamble sequences, and the additional transmission process may be performed using a second preamble sequence subset of the set of preamble sequences. In some aspects, the second preamble sequence subset may be different from the first preamble sequence subset.

[0069] In some aspects, the initial transmission process may be performed using a first RO subset of a RACH opportunity (RO) set, and the additional transmission process may be performed using a second RO subset of the RO set. In some aspects, the second RO subset may be different from the first RO subset. In some aspects, the initial transmission process may be performed using an initial request message preamble format, and the additional transmission process may be performed using at least one additional request message preamble format. In some aspects, at least one additional request message preamble format may be different from the initial request message preamble format.

[0070] As indicated by reference numeral 520, the additional transmission process may be performed using multiple transmissions. The multiple transmissions may correspond to multiple ROs 525. In some aspects, each transmission in the multiple transmissions may be associated with the same SSB beam. In some aspects, the multiple ROs may include multiple RO groups, wherein each RO group in the multiple RO groups serves as a virtual RO corresponding to at least one additional request message preamble.

[0071] As shown, at least one additional request message preamble may include a preamble sequence, and sending at least one additional request message preamble may include sending the preamble sequence in multiple transmissions. The preamble sequence may be a conventional preamble sequence defined by a wireless communication standard. In some aspects, the preamble sequence may be the same as the preamble sequence sent during the initial RACH attempt.

[0072] In some aspects, at least one additional request message preamble includes a plurality of preamble sequences linked to each other preamble sequence in the plurality of sequences. In some aspects, sending at least one additional request message preamble may include sending each of the plurality of preamble sequences in a corresponding one of the plurality of transmissions. Each of the plurality of preamble sequences may be linked to each other preamble sequence in the plurality of sequences based at least in part on a wireless communication standard, a configuration received from the base station 110, etc.

[0073] In some aspects, the plurality of preamble sequences may include a subset of a set of preamble sequences. In some aspects, the base station 110 may send and the UE 120 may receive a configuration of the subset of the set of preamble sequences. The configuration of the subset of the set of preamble sequences may be carried in the remaining minimum system information (RMSI).

[0074] In some aspects, sending the initial request message may include sending the initial request message according to an initial mapping of an initial RO to an initial set of PUSCH resources, and performing the alternative two-step RACH procedure may include sending an additional request message according to an additional mapping of additional ROs to an additional set of PUSCH resources. In some aspects, sending the initial request message may include sending an initial uplink reference signal (RS) using the initial set of PUSCH resources, and performing the alternative two-step RACH procedure may include sending an additional uplink RS using the additional set of PUSCH resources. In some aspects, the additional uplink RS may facilitate beam refinement associated with the base station 110.

[0075] Sending the initial request message may include sending the initial request message according to an initial mapping of an initial RO to an initial set of PUSCH resources.As further shown by reference numeral 520, performing an alternative two-step RACH procedure may include sending multiple additional request messages according to additional mappings of multiple additional ROs to multiple additional sets of PUSCH resources.

[0076] In some aspects, as shown, the additional mapping may include mapping of four additional ROs to two additional PUSCH resource sets. In some aspects, the base station 110 may send and the UE 120 may receive an indication of a time domain offset between at least one additional RO in the plurality of additional ROs and at least one additional PUSCH resource set in the plurality of additional PUSCH resource sets to which the at least one additional RO in the plurality of additional ROs is mapped. In some aspects, at least one additional RO in the plurality of additional ROs may include a first RO in the plurality of additional ROs to occur, a third RO in the plurality of ROs to occur, and so on. In some aspects, the time domain offset may include a slot offset.

[0077] In some aspects, base station 110 may send and UE 120 may receive an indication of a frequency domain offset between at least one additional RO in the plurality of additional ROs and at least one additional PUSCH resource set in the plurality of additional PUSCH resource sets to which at least one RO in the plurality of additional ROs is mapped. In some aspects, at least one additional RO in the plurality of additional ROs may include a first RO in the plurality of additional ROs to occur, a third RO in the plurality of ROs to occur, and so on. In some aspects, the frequency domain offset may include a subcarrier offset.

[0078] In some aspects, performing the initial two-step RACH procedure may include monitoring the PDCCH for an initial response message according to the initial reception procedure. As indicated by reference numeral 530, the UE 120 may perform an alternative two-step RACH procedure by monitoring an additional PDCCH for an additional response message corresponding to the additional request message according to an additional reception procedure, which may be different from the initial reception procedure. In some aspects, the additional reception procedure may include a coverage enhancement reception procedure.

[0079] In some aspects, as shown in reference numeral 535, the additional reception process may include monitoring multiple PDCCH monitoring candidates associated with multiple monitoring opportunities. As shown in reference numeral 540, the base station 110 may send an additional response message to the UE 120. In some aspects, as shown in the figure, each of the multiple monitoring opportunities may include an additional response message. In some aspects, each of the multiple PDCCH monitoring candidates may indicate an index associated with the additional response message, a specific position corresponding to each monitoring opportunity associated with the PDCCH monitoring candidate in the search space, etc. In some aspects, multiple PDCCH monitoring candidates may be associated with multiple time slots 545.

[0080] In some aspects, UE 120 may soft combine multiple PDCCH monitoring candidates to generate a combined PDCCH monitoring candidate. UE 120 may decode the combined PDCCH monitoring candidate and evaluate a cyclic redundancy check (CRC) associated with the combined PDCCH monitoring candidate to determine that the combined PDCCH monitoring candidate includes an additional response message.

[0081] As indicated by reference numeral 535, the plurality of monitoring opportunities may include a plurality of groups of monitoring opportunities, and each of the plurality of groups of monitoring opportunities may include a plurality of consecutive monitoring opportunities corresponding to a plurality of time slots 545 having an associated plurality of control resource sets (CORESETs). In some aspects, the plurality of CORESETs may be used as virtual monitoring opportunities corresponding to additional response messages.

[0082] UE 120 may perform an initial two-step RACH process by monitoring an initial response message during an initial RAR window. In some aspects, UE 120 may perform an alternative two-step RACH process by monitoring an additional response message corresponding to an additional request message during an additional RAR window. In some aspects, the additional RAR window may be different from the initial RAR window. In some aspects, the initial RAR window may have a first length, and the additional RAR window may have a second length different from the first length. In some aspects, base station 110 may send and UE 120 may receive a configuration of the first length and the second length in RMSI. In some aspects, the length of the initial RAR window may be the same as the length of the additional RAR window.

[0083] In some aspects, the initial two-step RACH process may include an initial offset between sending the initial request message and the start time of the initial RAR window, and the alternative two-step RACH process may include an additional offset between sending the additional request message and the start time of the additional RAR window. In some aspects, the additional offset may be different from the initial offset. In some aspects, the UE 120 may obtain one or more measurements associated with the signal, and the length of the initial RAR window may be based at least in part on the one or more measurements. In some aspects, the one or more measurements may include SSB-based RSRP, and based at least in part on the SSB-based RSRP satisfying a threshold, the length of the initial RAR window may be shorter than the length of the additional RAR window.

[0084] In some aspects, the initial two-step RACH process may include initial downlink control information (DCI) carried by the initial response message. The initial DCI may have a first size. In some aspects, the alternative two-step RACH process may include additional DCI carried by the additional response message and having a second size different from the first size. In some aspects, the initial two-step RACH process may include an initial DCI carried by the initial response message having content associated with a first interpretation of the UE. The alternative two-step RACH process may include additional DCI carried by the additional response message having content associated with a second interpretation of the UE. In some aspects, the second interpretation may be different from the first interpretation.

[0085] Various aspects of the above techniques can facilitate enhanced RACH coverage without unnecessarily increasing resource consumption. In some aspects, the above alternative RACH process can use alternative transmission methods for request message preambles, alternative mappings between RO and PUSCH resources, alternative methods for monitoring and receiving response messages, alternative RAR windows, alternative sizes of DCI carried by response messages, alternative interpretations of DCI content, etc. In this way, the base station can facilitate increased coverage of the RACH process without using unnecessary resources.

[0086] As mentioned above, providing Figure 5 As an example. Other examples may be related to Figure 5 Different than described.

[0087] Figure 6 6 is a diagram illustrating an exemplary process 600 performed, for example, by a UE in accordance with the present disclosure. Exemplary process 600 is an example of a UE (eg, UE 120, etc.) performing operations associated with an alternative two-step RACH procedure.

[0088] like Figure 6 As shown, in some aspects, process 600 may include performing an initial RACH attempt by sending an initial request message for an initial two-step RACH procedure to a base station (block 610). For example, a UE (e.g., using transmit processor 264, controller / processor 280, memory 282, etc.) may perform an initial RACH attempt by sending an initial request message for an initial two-step RACH procedure to a base station, as described above.

[0089] like Figure 6 As further shown, in some aspects, process 600 may include performing additional RACH attempts using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to an initial request message of the two-step RACH procedure was not received during the initial RAR window (block 620). For example, the UE (e.g., using receive processor 258, transmit processor 264, controller / processor 280, memory 282, etc.) may perform additional RACH attempts using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to an initial request message of the two-step RACH procedure was not received during the initial RAR window, as described above.

[0090] Process 600 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in combination with one or more other processes described elsewhere herein.

[0091] In a first aspect, process 600 includes obtaining one or more measurements associated with a signal, wherein the UE is to perform additional RACH attempts based at least in part on the one or more measurements.

[0092] In a second aspect, alone or in combination with the first aspect, the one or more measurements include RSRP based on SSB, and the UE is to perform an additional RACH attempt based at least in part on determining that the RSRP based on SSB satisfies a threshold.

[0093] In a third aspect, alone or in combination with one or more of the first and second aspects, sending an initial request message includes sending an initial request message preamble according to an initial transmission procedure, and performing an alternative two-step RACH procedure includes sending at least one additional request message preamble according to an additional transmission procedure, wherein the additional transmission procedure is different from the initial transmission procedure.

[0094] In a fourth aspect, alone or in combination with the third aspect, the additional transmission procedure comprises a coverage enhancement transmission procedure.

[0095] In a fifth aspect, alone or in combination with one or more of the third to fourth aspects, the initial transmission process is performed using a first transmission power, and the additional transmission process is performed using a second transmission power higher than the first transmission power.

[0096] In the sixth aspect, alone or in combination with one or more of the third to fifth aspects, the initial transmission process is performed using a first preamble code sequence subset of the preamble code sequence set, and the additional transmission process is performed using a second preamble code sequence subset of the preamble code sequence set, wherein the second preamble code sequence subset is different from the first preamble code sequence subset.

[0097] In a seventh aspect, alone or in combination with one or more of the third to sixth aspects, an initial transmission process is performed using a first RO subset of the RO set, and an additional transmission process is performed using a second RO subset of the RO set, wherein the second RO subset is different from the first RO subset.

[0098] In the eighth aspect, alone or in combination with one or more of the third to seventh aspects, the initial transmission process is performed using an initial request message preamble format, and the additional transmission process is performed using at least one additional request message preamble format, wherein at least one additional request message preamble format is different from the initial request message preamble format.

[0099] In a ninth aspect, alone or in combination with one or more of the third to eighth aspects, the additional transmission process is performed using multiple transmissions, wherein the multiple transmissions correspond to multiple ROs.

[0100] In a tenth aspect, either alone or in combination with the ninth aspect, each transmission of the plurality of transmissions is associated with the same SSB beam.

[0101] In an eleventh aspect, alone or in combination with one or more of the ninth to tenth aspects, the plurality of ROs includes a plurality of RO groups, and each of the plurality of RO groups serves as a virtual RO corresponding to at least one additional request message preamble.

[0102] In a twelfth aspect, alone or in combination with one or more of the third to eleventh aspects, at least one additional request message preamble comprises a preamble sequence, and sending at least one additional request message preamble comprises sending the preamble sequence in multiple transmissions.

[0103] In the thirteenth aspect, alone or in combination with one or more of the third to twelfth aspects, at least one additional request message preamble code includes multiple preamble code sequences, each preamble code sequence in the multiple preamble code sequences is linked to each other preamble code sequence in the multiple sequences, and sending at least one additional request message preamble code includes sending each preamble code sequence in the multiple preamble code sequences in a corresponding one of the multiple transmissions.

[0104] In a fourteenth aspect, either alone or in combination with the thirteenth aspect, each preamble sequence in a plurality of preamble sequences is linked with each other preamble sequence in a plurality of sequences based at least in part on at least one of: a wireless communication standard, a configuration received from a base station, or a combination thereof.

[0105] In a fifteenth aspect, alone or in combination with one or more of the thirteenth to fourteenth aspects, the plurality of preamble sequences comprises a subset of a set of preamble sequences, and the process 600 comprises receiving a configuration of the subset of the set of preamble sequences from a base station.

[0106] In a sixteenth aspect, alone or in combination with the fifteenth aspect, the configuration of a subset of the set of preamble sequences is carried in the RMSI.

[0107] In the seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, sending the initial request message includes sending the initial request message based on an initial mapping of an initial RO to an initial set of PUSCH resources, and performing an alternative two-step RACH process includes sending an additional request message based on an additional mapping of an additional RO to an additional set of PUSCH resources.

[0108] In an eighteenth aspect, alone or in combination with the seventeenth aspect, sending an initial request message includes sending an initial uplink RS using an initial set of PUSCH resources, and performing an alternative two-step RACH process includes sending an additional uplink RS using an additional set of PUSCH resources, wherein the additional uplink RS is used to facilitate beam refinement associated with a base station.

[0109] In the nineteenth aspect, alone or in combination with one or more of the first to eighteenth aspects, sending the initial request message includes sending the initial request message according to an initial mapping of an initial RO to an initial set of PUSCH resources, and performing an alternative two-step RACH process includes sending multiple additional request messages according to additional mappings of multiple additional ROs to multiple additional PUSCH resource sets.

[0110] In a twentieth aspect, alone or in combination with the nineteenth aspect, the additional mapping comprises mapping of four additional ROs to two sets of additional PUSCH resources.

[0111] In aspect twenty-one, alone or in combination with one or more of aspects nineteen to twentieth, process 600 includes receiving an indication of a time domain offset between at least one additional RO among a plurality of additional ROs and at least one set of a plurality of additional PUSCH resource sets to which at least one additional RO among the plurality of additional ROs is mapped.

[0112] In a twenty-second aspect, alone or in combination with the twenty-first aspect, at least one RO of the plurality of additional ROs comprises a first RO to occur among the plurality of additional ROs.

[0113] In a twenty-third aspect, alone or in combination with the twenty-first aspect, at least one RO of the plurality of additional ROs further comprises a third RO to occur in the plurality of additional ROs.

[0114] In a twenty-fourth aspect, alone or in combination with one or more of aspects twenty-first to twenty-third, the time domain offset comprises a time slot offset.

[0115] In aspect twenty-fifth, alone or in combination with one or more of aspects nineteen to twenty-fourth, process 600 includes receiving an indication of a frequency domain offset between at least one additional RO among a plurality of additional ROs and at least one set of at least one RO among a plurality of additional PUSCH resource sets to which the plurality of additional ROs are mapped.

[0116] In a twenty-sixth aspect, alone or in combination with the twenty-fifth aspect, at least one RO of the plurality of additional ROs comprises a first RO to occur among the plurality of additional ROs.

[0117] In a twenty-seventh aspect, alone or in combination with the twenty-fifth aspect, at least one RO of the plurality of additional ROs further comprises a third RO to occur in the plurality of additional ROs.

[0118] In a twenty-eighth aspect, either alone or in combination with one or more of aspects twenty-fifth to twenty-seventh, the frequency domain offset comprises a subcarrier offset.

[0119] In the twenty-ninth aspect, alone or in combination with one or more of the first to twenty-eighth aspects, performing an initial two-step RACH process includes monitoring an initial PDCCH for an initial response message according to an initial reception process; and performing an alternative two-step RACH process includes monitoring an additional PDCCH for an additional response message corresponding to an additional request message according to an additional reception process, wherein the additional reception process is different from the initial reception process.

[0120] In a thirtieth aspect, alone or in combination with the twenty-ninth aspect, the additional reception process includes a coverage enhancement reception process.

[0121] In the thirty-first aspect, alone or in combination with one or more of the twenty-ninth to thirtieth aspects, the additional reception process includes monitoring a plurality of PDCCH monitoring candidates associated with a plurality of monitoring opportunities.

[0122] In a thirty-second aspect, either alone or in combination with the thirty-first aspect, each monitoring opportunity of the plurality of monitoring opportunities comprises an additional response message.

[0123] In aspect thirty-third, alone or in combination with one or more of aspects thirty-first to thirty-second, each of a plurality of PDCCH monitoring candidates indicates at least one of: an index associated with an additional response message, a specific position in the search space corresponding to each monitoring opportunity associated with the PDCCH monitoring candidate, or a combination thereof.

[0124] In a thirty-fourth aspect, alone or in combination with the thirty-third aspect, a plurality of PDCCH monitoring candidates are associated with a plurality of time slots.

[0125] In aspect thirty-fifth, alone or in combination with one or more of aspects thirty-first to thirty-fourth, process 600 includes soft combining multiple PDCCH monitoring candidates to generate a combined PDCCH monitoring candidate; decoding the combined PDCCH monitoring candidate; and evaluating the CRC associated with the combined PDCCH monitoring candidate to determine that the combined PDCCH monitoring candidate includes an additional response message.

[0126] In aspect thirty-six, either alone or in combination with one or more of aspects thirty-one to thirty-fifth, the plurality of monitoring opportunities comprises a plurality of groups of monitoring opportunities, each of the plurality of groups of monitoring opportunities comprising a plurality of consecutive monitoring opportunities corresponding to a plurality of time slots having an associated plurality of CORESETs.

[0127] In a thirty-seventh aspect, alone or in combination with the thirty-sixth aspect, a plurality of CORESETs are used as virtual monitoring opportunities corresponding to additional response messages.

[0128] In an aspect thirty-eight, either alone or in combination with one or more of aspects one to thirty-seven, performing an initial two-step RACH procedure includes monitoring an initial response message during an initial RAR window; and performing an alternative two-step RACH procedure includes monitoring an additional response message corresponding to an additional request message during an additional RAR window, wherein the additional RAR window is different from the initial RAR window.

[0129] In a thirty-ninth aspect, alone or in combination with the thirty-eighth aspect, the initial RAR window has a first length and the additional RAR window has a second length different from the first length.

[0130] In a fortieth aspect, alone or in combination with the thirty-ninth aspect, process 600 comprises receiving a configuration of a first length and a second length in a RMSI.

[0131] In the forty-first aspect, alone or in combination with the thirty-eighth aspect, the length of the initial RAR window may be the same as the length of the additional RAR window.

[0132] In aspect 42, alone or in combination with one or more of aspects 38 to 41, the initial two-step RACH process includes an initial offset between sending an initial request message and the start time of an initial RAR window, and the alternative two-step RACH process includes an additional offset between sending an additional request message and the start time of an additional RAR window, wherein the additional offset may be different from the initial offset.

[0133] In a forty-third aspect, alone or in combination with one or more of the first to forty-second aspects, process 600 comprises obtaining one or more measurements associated with the signal, wherein the length of the initial RAR window may be based at least in part on the one or more measurements.

[0134] In a forty-fourth aspect, alone or in combination with the forty-third aspect, the one or more measurements may include SSB-based RSRP, and based at least in part on the SSB-based RSRP satisfying a threshold, the length of the initial RAR window may be shorter than the length of the additional RAR window.

[0135] In a forty-fourth aspect, either alone or in combination with one or more of aspects one to forty-four, an initial two-step RACH procedure includes an initial DCI carried by an initial response message, the initial DCI having a first size, and an alternative two-step RACH procedure includes an additional DCI carried by an additional response message, wherein the additional DCI has a second size different from the first size.

[0136] In aspect 46, either alone or in combination with one or more of aspects 1 to 45, the initial two-step RACH process includes an initial DCI carried by an initial response message, the initial DCI including content associated with a first interpretation of the UE; and the alternative two-step RACH process includes an additional DCI carried by an additional response message, the additional DCI including content associated with a second interpretation of the UE, wherein the second interpretation is different from the first interpretation.

[0137] Although Figure 6 An exemplary block diagram of process 600 is shown, but in some aspects, process 600 may include Figure 6 Additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in process 600. Additionally or alternatively, two or more blocks of process 600 may be executed in parallel.

[0138] Figure 7 7 is a diagram illustrating an exemplary process 700, performed, for example, by a base station, in accordance with the present disclosure. Exemplary process 700 is an example of a base station (eg, base station 110, etc.) performing operations associated with an alternative two-step RACH procedure.

[0139] like Figure 7 As shown, in some aspects, process 700 may include receiving an initial request message for an initial two-step RACH procedure from a UE, where the initial request message corresponds to an initial RACH attempt (block 710). For example, a base station (e.g., using receive processor 238, controller / processor 240, memory 242, etc.) receives an initial request message for an initial two-step RACH procedure from a UE, as described above. In some aspects, the initial request message corresponds to an initial RACH attempt.

[0140] like Figure 7 As further shown, in some aspects, process 700 may include receiving an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed based at least in part on the UE not receiving an initial response message corresponding to the initial request message during the initial RAR window (block 720). For example, a base station (e.g., using receive processor 238, controller / processor 240, memory 242, etc.) may receive an additional request message for an alternative two-step RACH procedure, as described above. In some aspects, the additional request message corresponds to an additional RACH attempt performed based at least in part on the UE not receiving an initial response message corresponding to the initial request message during the initial RAR window.

[0141] Process 700 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in combination with one or more other processes described elsewhere herein.

[0142] In a first aspect, additional RACH attempts are performed based at least in part on one or more measurements associated with a signal.

[0143] In a second aspect, alone or in combination with the first aspect, the one or more measurements include an SSB-based RSRP, and an additional RACH attempt is performed based at least in part on the SSB-based RSRP satisfying a threshold.

[0144] In a third aspect, alone or in combination with one or more of the first and second aspects, receiving the initial request message includes receiving an initial request message preamble according to an initial transmission process, and process 700 includes receiving at least one additional request message preamble according to an additional transmission process different from the initial transmission process, wherein the at least one additional request message preamble corresponds to an alternative two-step RACH process.

[0145] In a fourth aspect, alone or in combination with the third aspect, the additional transmission procedure comprises a coverage enhancement transmission procedure.

[0146] In a fifth aspect, alone or in combination with one or more of the third to fourth aspects, the initial transmission process is performed using a first transmission power, and the additional transmission process is performed using a second transmission power higher than the first transmission power.

[0147] In the sixth aspect, alone or in combination with one or more of the third to fifth aspects, the initial transmission process is performed using a first preamble code sequence subset of the preamble code sequence set, and the additional transmission process is performed using a second preamble code sequence subset of the preamble code sequence set, wherein the second preamble code sequence subset is different from the first preamble code sequence subset.

[0148] In a seventh aspect, alone or in combination with one or more of the third to sixth aspects, an initial transmission process is performed using a first RO subset of the RO set, and an additional transmission process is performed using a second RO subset of the RO set, wherein the second RO subset is different from the first RO subset.

[0149] In the eighth aspect, alone or in combination with one or more of the third to seventh aspects, the initial transmission process is performed using an initial request message preamble format, and the additional transmission process is performed using at least one additional request message preamble format, wherein at least one additional request message preamble format is different from the initial request message preamble format.

[0150] In a ninth aspect, alone or in combination with one or more of the third to eighth aspects, the additional transmission process is performed using multiple transmissions, wherein the multiple transmissions correspond to multiple ROs.

[0151] In a tenth aspect, either alone or in combination with the ninth aspect, each transmission of the plurality of transmissions is associated with the same SSB beam.

[0152] In an eleventh aspect, alone or in combination with one or more of the ninth to tenth aspects, the plurality of ROs includes a plurality of RO groups, and each of the plurality of RO groups serves as a virtual RO corresponding to at least one additional request message preamble.

[0153] In a twelfth aspect, alone or in combination with one or more of the third to eleventh aspects, at least one additional request message preamble comprises a preamble sequence, and receiving at least one additional request message preamble comprises receiving the preamble sequence in multiple transmissions.

[0154] In the thirteenth aspect, alone or in combination with one or more of the third to twelfth aspects, at least one additional request message preamble code includes multiple preamble code sequences, each preamble code sequence in the multiple preamble code sequences is linked to each other preamble code sequence in the multiple sequences, and receiving at least one additional request message preamble code includes receiving each preamble code sequence in the multiple preamble code sequences in a corresponding one of the multiple transmissions.

[0155] In a fourteenth aspect, either alone or in combination with the thirteenth aspect, each preamble sequence in a plurality of preamble sequences is linked with each other preamble sequence in a plurality of sequences based at least in part on at least one of: a wireless communication standard, a configuration sent to a UE, or a combination thereof.

[0156] In a fifteenth aspect, alone or in combination with one or more of the thirteenth to fourteenth aspects, the plurality of preamble sequences comprises a subset of a set of preamble sequences, and the process 700 comprises configuration of the subset of the set of preamble sequences sent to the UE.

[0157] In a sixteenth aspect, alone or in combination with the fifteenth aspect, the configuration of a subset of the set of preamble sequences is carried in the RMSI.

[0158] In a seventeenth aspect, alone or in combination with one or more of the first to sixteenth aspects, the initial request message includes an initial mapping of an initial RO to an initial set of PUSCH resources, and process 700 includes receiving an additional request message based on an additional mapping of an additional RO to an additional set of PUSCH resources, wherein the additional request message corresponds to an alternative two-step RACH process.

[0159] In an eighteenth aspect, alone or in combination with the seventeenth aspect, receiving the initial request message includes receiving an initial uplink RS using an initial set of PUSCH resources, and process 700 includes receiving an additional uplink RS using an additional set of PUSCH resources, wherein the additional uplink RS is used to facilitate beam refinement associated with the base station, and wherein the additional uplink RS corresponds to an alternative two-step RACH process.

[0160] In a nineteenth aspect, alone or in combination with one or more of the first to eighteenth aspects, receiving an initial request message includes receiving an initial request message based on an initial mapping of an initial RO to an initial set of PUSCH resources, and process 700 includes receiving multiple additional request messages based on additional mappings of multiple additional ROs to multiple additional PUSCH resource sets, wherein the multiple additional request messages correspond to an alternative two-step RACH process.

[0161] In a twentieth aspect, alone or in combination with the nineteenth aspect, the additional mapping comprises mapping of four additional ROs to two sets of additional PUSCH resources.

[0162] In aspect twenty-one, alone or in combination with one or more of aspects nineteen to twentieth, process 700 includes sending an indication of a time domain offset between at least one additional RO among a plurality of additional ROs and at least one set of a plurality of additional PUSCH resource sets to which at least one additional RO among a plurality of additional ROs is mapped.

[0163] In a twenty-second aspect, alone or in combination with the twenty-first aspect, at least one RO of the plurality of additional ROs comprises a first RO to occur among the plurality of additional ROs.

[0164] In a twenty-third aspect, alone or in combination with the twenty-first aspect, at least one RO of the plurality of additional ROs further comprises a third RO to occur in the plurality of additional ROs.

[0165] In a twenty-fourth aspect, alone or in combination with one or more of aspects twenty-first to twenty-third, the time domain offset comprises a time slot offset.

[0166] In aspect twenty-fifth, alone or in combination with one or more of aspects nineteen to twenty-fourth, process 700 includes sending an indication of a frequency domain offset between at least one additional RO among a plurality of additional ROs and at least one set of at least one RO among a plurality of additional PUSCH resource sets to which the plurality of additional ROs are mapped.

[0167] In a twenty-sixth aspect, alone or in combination with the twenty-fifth aspect, at least one RO of the plurality of additional ROs comprises a first RO to occur among the plurality of additional ROs.

[0168] In a twenty-seventh aspect, alone or in combination with the twenty-fifth aspect, at least one RO of the plurality of additional ROs further comprises a third RO to occur in the plurality of additional ROs.

[0169] In a twenty-eighth aspect, either alone or in combination with one or more of aspects twenty-fifth to twenty-seventh, the frequency domain offset comprises a subcarrier offset.

[0170] In a twenty-ninth aspect, alone or in combination with one or more of the first to twenty-eight aspects, process 700 includes sending an additional response message corresponding to an additional request message of an alternative two-step RACH procedure.

[0171] In a thirtieth aspect, alone or in combination with the twenty-ninth aspect, an additional response message is sent using multiple monitoring opportunities corresponding to multiple PDCCH monitoring candidates.

[0172] In the thirty-first aspect, alone or in combination with the thirtieth aspect, each monitoring opportunity of the plurality of monitoring opportunities includes an additional response message.

[0173] In aspect 32, either alone or in combination with one or more of aspects 29 to 30, each of a plurality of PDCCH monitoring candidates indicates at least one of: an index associated with an additional response message, a specific position in the search space corresponding to each monitoring opportunity associated with the PDCCH monitoring candidate, or a combination thereof.

[0174] In a thirty-third aspect, alone or in combination with one or more of the thirtieth to thirty-second aspects, a plurality of PDCCH monitoring candidates are associated with a plurality of time slots.

[0175] In aspect thirty-four, either alone or in combination with one or more of aspects twenty-ninth to thirty-third, the plurality of monitoring opportunities comprises a plurality of groups of monitoring opportunities, each of the plurality of groups of monitoring opportunities comprising a plurality of consecutive monitoring opportunities corresponding to a plurality of time slots having an associated plurality of CORESETs.

[0176] In a thirty-fifth aspect, alone or in combination with the thirty-fourth aspect, a plurality of CORESETs are used as virtual monitoring opportunities corresponding to additional response messages.

[0177] In a thirty-sixth aspect, alone or in combination with one or more of aspects 1 to 35, an alternative two-step RACH procedure includes an additional RAR window different from the initial RAR window.

[0178] In a thirty-seventh aspect, alone or in combination with the first to thirty-sixth aspects, the initial RAR window has a first length and the additional RAR window has a second length different from the first length.

[0179] In a thirty-eighth aspect, alone or in combination with the thirty-seventh aspect, process 700 includes sending a configuration of a first length and a second length in a RMSI.

[0180] In a thirty-ninth aspect, either alone or in combination with the thirty-seventh aspect, the length of the initial RAR window is the same as the length of the additional RAR window.

[0181] In the fortieth aspect, alone or in combination with one or more of aspects thirty-seven to thirty-nine, the initial two-step RACH process includes an initial offset between sending an initial request message and a start time of an initial RAR window, and the alternative two-step RACH process includes an additional offset between sending an additional request message and a start time of an additional RAR window, wherein the additional offset is different from the initial offset.

[0182] In a forty-first aspect, alone or in combination with one or more of the first to fortieth aspects, a length of the initial RAR window is based at least in part on one or more measurements associated with the signal.

[0183] In the 42nd aspect, alone or in combination with the 41st aspect, the one or more measurements include SSB-based RSRP, and based at least in part on the SSB-based RSRP satisfying a threshold, the length of the initial RAR window may be shorter than the length of the additional RAR window.

[0184] In an aspect 43, either alone or in combination with one or more of aspects 1 to 42, an initial two-step RACH process includes an initial DCI carried by an initial response message, the initial DCI having a first size, and an alternative two-step RACH process includes an additional DCI carried by an additional response message, wherein the additional DCI has a second size different from the first size.

[0185] In a 44th aspect, either alone or in combination with one or more of aspects 1 to 43, the initial two-step RACH process includes an initial DCI carried by an initial response message, the initial DCI including content associated with a first interpretation of the UE; and the alternative two-step RACH process includes an additional DCI carried by an additional response message, the additional DCI including content associated with a second interpretation of the UE, wherein the second interpretation is different from the first interpretation.

[0186] Although Figure 7 An exemplary block diagram of process 7600 is shown, but in some aspects, process 700 may include Figure 7 Additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in. Additionally or alternatively, two or more blocks of process 700 may be executed in parallel.

[0187] The following provides an overview of some aspects of the disclosure:

[0188] Aspect 1: A wireless communication method performed by a user equipment (UE), comprising: performing an initial two-step random access channel (RACH) attempt by sending an initial request message of an initial RACH process to a base station; and performing an additional RACH attempt using an alternative two-step RACH process based at least in part on determining that an initial response message corresponding to the initial request message of the two-step RACH process was not received during an initial random access response (RAR) window.

[0189] Aspect 2: The method of Aspect 1, further reporting: obtaining one or more measurements associated with the signal, wherein the UE will perform the additional RACH attempt at least in part based on the one or more measurements.

[0190] Aspect 3: The method of Aspect 2, wherein the one or more measurements include a reference signal received power (RSRP) based on a synchronization signal block (SSB), and wherein the UE will perform an additional RACH attempt based at least in part on determining that the RSRP based on the SSB satisfies a threshold.

[0191] Aspect 4: A method according to any one of Aspects 1-3, wherein sending an initial request message includes sending an initial request message preamble according to an initial transmission process, and wherein performing an alternative two-step RACH process includes sending at least one additional request message preamble according to an additional transmission process, wherein the additional transmission process is different from the initial transmission process.

[0192] Aspect 5: The method of Aspect 4, wherein the additional transmission process includes a coverage enhancement transmission process.

[0193] Aspect 6: The method of aspect 4 or 5, wherein the initial transmission process is performed using a first transmission power, and wherein the additional transmission process is performed using a second transmission power higher than the first transmission power.

[0194] Aspect 7: A method according to any one of Aspects 4-6, wherein an initial transmission process is performed using a first preamble code sequence subset of a preamble code sequence set, and wherein an additional transmission process is performed using a second preamble code sequence subset of the preamble code sequence set, wherein the second preamble code sequence subset is different from the first preamble code sequence subset.

[0195] Aspect 8: The method of any one of Aspects 4-7, wherein the initial transmission process is performed using a first RO subset of a RACH opportunity (RO) set, and wherein the additional transmission process is performed using a second RO subset of the RO set, wherein the second RO subset is different from the first RO subset.

[0196] Aspect 9: A method according to any one of Aspects 4-8, wherein an initial transmission process is performed using an initial request message preamble format, and wherein an additional transmission process is performed using at least one additional request message preamble format, wherein at least one additional request message preamble format is different from the initial request message preamble format.

[0197] Aspect 10: The method of any one of aspects 4-9, wherein the additional transmission process is performed using multiple transmissions, wherein the multiple transmissions correspond to multiple RACH opportunities (ROs).

[0198] Aspect 11: The method of Aspect 10, wherein each of the multiple transmissions is associated with the same synchronization signal block beam.

[0199] Aspect 12: The method of aspect 10 or 11, wherein the plurality of ROs comprises a plurality of RO groups, wherein each RO group in the plurality of RO groups serves as a virtual RO corresponding to at least one additional request message preamble.

[0200] Aspect 13: The method of any one of Aspects 4-12, wherein at least one additional request message preamble comprises a preamble sequence, and wherein sending at least one additional request message preamble comprises sending the preamble sequence in multiple transmissions.

[0201] Aspect 14: A method of any one of Aspects 4-13, wherein at least one additional request message preamble comprises multiple preamble sequences, wherein each preamble sequence in the multiple preamble sequences is linked to each other preamble sequence in the multiple sequences, and wherein sending at least one additional request message preamble comprises sending each preamble sequence in the multiple preamble sequences in a corresponding one of the multiple transmissions.

[0202] Aspect 15: The method of Aspect 14, wherein each preamble sequence in the plurality of preamble sequences is linked with each other preamble sequence in the plurality of sequences based at least in part on at least one of: a wireless communication standard, a configuration received from a base station, or a combination thereof.

[0203] Aspect 16: The method of Aspect 14 or 15, wherein the plurality of preamble code sequences include a subset of a set of preamble code sequences, and the method further comprises receiving a configuration of the subset of the set of preamble code sequences from a base station.

[0204] Aspect 17: The method of Aspect 16, wherein the configuration of the subset of the preamble code sequence set is carried in the remaining minimum system information.

[0205] Aspect 18: A method of any one of Aspects 1-17, wherein sending an initial request message includes sending an initial request message based on an initial mapping of an initial RACH opportunity (RO) to an initial set of physical uplink shared channel (PUSCH) resources, and wherein performing an alternative two-step RACH process includes sending an additional request message based on an additional mapping of an additional RO to an additional set of PUSCH resources.

[0206] Aspect 19: The method of Aspect 18, wherein sending the initial request message includes sending an initial uplink reference signal (RS) using an initial set of PUSCH resources, and wherein performing an alternative two-step RACH process includes sending an additional uplink RS using an additional set of PUSCH resources, wherein the additional uplink RS is used to facilitate beam refinement associated with a base station.

[0207] Aspect 20: A method of any one of Aspects 1-19, wherein sending an initial request message includes sending the initial request message according to an initial mapping of an initial RACH opportunity (RO) to an initial set of physical uplink shared channel (PUSCH) resources, and wherein performing an alternative two-step RACH process includes sending multiple additional request messages according to additional mappings of multiple additional ROs to multiple additional PUSCH resource sets.

[0208] Aspect 21: The method of Aspect 20, wherein the additional mapping comprises mapping of four additional ROs to two sets of additional PUSCH resources.

[0209] Aspect 22: The method of Aspect 20 or 21 further includes: receiving an indication of a time domain offset between at least one additional RO among the multiple additional ROs and at least one set of multiple additional PUSCH resource sets to which the at least one additional RO among the multiple additional ROs is mapped.

[0210] Aspect 23: The method of Aspect 22, wherein at least one RO of the plurality of additional ROs comprises a first RO to occur among the plurality of additional ROs.

[0211] Aspect 24: The method of Aspect 22, wherein at least one RO of the plurality of additional ROs further comprises a third RO to be generated among the plurality of additional ROs.

[0212] Aspect 25: The method of Aspects 22-24, wherein the time domain offset comprises a time slot offset.

[0213] Aspect 26: The method of any one of Aspects 20-25, further comprising receiving an indication of a frequency domain offset between at least one additional RO of the plurality of additional ROs and at least one set of at least one RO of the plurality of additional PUSCH resource sets to which the plurality of additional ROs are mapped.

[0214] Aspect 27: The method of Aspect 26, wherein at least one RO of the plurality of additional ROs comprises a first RO to occur among the plurality of additional ROs.

[0215] Aspect 28: The method of Aspect 26, wherein at least one RO of the plurality of additional ROs further comprises a third RO to be occurred among the plurality of additional ROs.

[0216] Aspect 29: The method of any one of Aspects 26-28, wherein the frequency domain offset comprises a subcarrier offset.

[0217] Aspect 30: A method of any one of Aspects 1-29, wherein performing an initial two-step RACH process includes monitoring an initial physical downlink control channel (PDCCH) for an initial response message according to an initial reception process; and wherein performing an alternative two-step RACH process includes monitoring an additional PDCCH for an additional response message corresponding to an additional request message according to an additional reception process, wherein the additional reception process is different from the initial reception process.

[0218] Aspect 31: The method of Aspect 30, wherein the additional reception process includes a coverage enhancement reception process.

[0219] Aspect 32: The method of aspect 30 or 31, wherein the additional reception process comprises monitoring a plurality of PDCCH monitoring candidates associated with a plurality of monitoring opportunities.

[0220] Aspect 33: The method of Aspect 32, wherein each of the plurality of monitoring opportunities comprises an additional response message.

[0221] Aspect 34: The method of Aspect 32 or 33, wherein each of the multiple PDCCH monitoring candidates indicates at least one of: an index associated with an additional response message, a specific position in the search space corresponding to each monitoring opportunity associated with the PDCCH monitoring candidate, or a combination thereof.

[0222] Aspect 35: The method of Aspect 34, wherein the plurality of PDCCH monitoring candidates are associated with a plurality of time slots.

[0223] Aspect 36: The method of any one of Aspects 32-35 further includes: soft combining multiple PDCCH monitoring candidates to generate a combined PDCCH monitoring candidate; decoding the combined PDCCH monitoring candidate; and evaluating the CRC associated with the combined PDCCH monitoring candidate to determine that the combined PDCCH monitoring candidate includes an additional response message.

[0224] Aspect 37: The method of any one of Aspects 32-36, wherein the plurality of monitoring opportunities comprises a plurality of groups of monitoring opportunities, each group of monitoring opportunities in the plurality of groups of monitoring opportunities comprising a plurality of consecutive monitoring opportunities corresponding to a plurality of time slots having an associated plurality of control resource sets (CORESETs).

[0225] Aspect 38: The method of Aspect 37, wherein a plurality of CORESETs are used as virtual monitoring opportunities corresponding to additional response messages.

[0226] Aspect 39: A method of any one of Aspects 1-38, wherein performing an initial two-step RACH process includes monitoring an initial response message during an initial RAR window; and wherein performing an alternative two-step RACH process includes monitoring an additional response message corresponding to an additional request message during an additional RAR window, wherein the additional RAR window is different from the initial RAR window.

[0227] Aspect 40: The method of Aspect 39, wherein the initial RAR window has a first length, and wherein the additional RAR window has a second length different from the first length.

[0228] Aspect 41: The method of Aspect 40, further comprising receiving a configuration of the first length and the second length in remaining minimum system information (RMSI).

[0229] Aspect 42: The method of Aspect 39, wherein the length of the initial RAR window is the same as the length of the additional RAR window.

[0230] Aspect 43: A method of any of Aspects 39-42, wherein the initial two-step RACH process includes an initial offset between sending an initial request message and the start time of an initial RAR window; and wherein the alternative two-step RACH process includes an additional offset between sending an additional request message and the start time of an additional RAR window, wherein the additional offset may be different from the initial offset.

[0231] Aspect 44: The method of any one of Aspects 1-43, further comprising: obtaining one or more measurements associated with the signal, wherein the length of the initial RAR window may be based at least in part on the one or more measurements.

[0232] Aspect 45: The method of Aspect 44, wherein one or more measurements may include a synchronization signal block (SSB)-based reference signal received power (RSRP), and wherein the length of the initial RAR window may be shorter than the length of the additional RAR window based at least in part on the SSB-based RSRP satisfying a threshold.

[0233] Aspect 46: A method of any one of Aspects 1-45, wherein the initial two-step RACH process includes initial downlink control information (DCI) carried by an initial response message, the initial DCI having a first size; and wherein the alternative two-step RACH process includes additional DCI carried by an additional response message, wherein the additional DCI has a second size different from the first size.

[0234] Aspect 47, a method of any one of methods 1-46, wherein the initial two-step RACH process includes initial downlink control information (DCI) carried by an initial response message, the initial DCI including content associated with a first interpretation of the UE; and wherein the alternative two-step RACH process includes an additional DCI carried by an additional response message, the additional DCI including content associated with a second interpretation of the UE, wherein the second interpretation is different from the first interpretation.

[0235] Aspect 48: A wireless communication method performed by a base station, comprising: receiving an initial request message for an initial two-step random access channel (RACH) procedure from a user equipment (UE), wherein the initial request message corresponds to an initial RACH attempt; and receiving an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed at least in part based on the UE not receiving an initial response message corresponding to the initial request message during an initial random access response (RAR) window.

[0236] Aspect 49: The method of Aspect 48, wherein the additional RACH attempt is performed based at least in part on one or more measurements associated with the signal.

[0237] Aspect 50: The method of Aspect 49, wherein the one or more measurements include a synchronization signal block (SSB)-based reference signal received power (RSRP), and wherein an additional RACH attempt is performed at least in part based on the SSB-based RSRP satisfying a threshold.

[0238] Aspect 51: A method according to any one of Aspects 48-50, wherein receiving an initial request message includes receiving an initial request message preamble according to an initial transmission process, and wherein the method further includes receiving at least one additional request message preamble according to an additional transmission process different from the initial transmission process, wherein at least one additional request message preamble corresponds to an alternative two-step RACH process.

[0239] Aspect 52: The method of Aspect 51, wherein the additional transmission process includes a coverage enhancement transmission process.

[0240] Aspect 53: The method of aspect 51 or 52, wherein the initial transmission process is performed using a first transmission power, and the additional transmission process is performed using a second transmission power higher than the first transmission power.

[0241] Aspect 54: A method according to any one of Aspects 51-53, wherein an initial transmission process is performed using a first preamble code sequence subset of a preamble code sequence set, and wherein an additional transmission process is performed using a second preamble code sequence subset of the preamble code sequence set, wherein the second preamble code sequence subset is different from the first preamble code sequence subset.

[0242] Aspect 55: The method of any one of Aspects 51-54, wherein the initial transmission process is performed using a first RACH opportunity (RO) subset of the RO set, and the additional transmission process is performed using a second RO subset of the RO set, wherein the second RO subset is different from the first RO subset.

[0243] Aspect 56: A method according to any one of Aspects 51-55, wherein the initial transmission process is performed using an initial request message preamble format, and wherein the additional transmission process is performed using at least one additional request message preamble format, wherein at least one additional request message preamble format is different from the initial request message preamble format.

[0244] Aspect 57: The method of any one of Aspects 51-56, wherein the additional transmission process is performed using multiple transmissions, wherein the multiple transmissions correspond to multiple RACH opportunities (ROs).

[0245] Aspect 58: The method of Aspect 57, wherein each of the multiple transmissions is associated with the same synchronization signal block beam.

[0246] Aspect 59: The method of Aspect 57 or 58, wherein the plurality of ROs comprises a plurality of RO groups, and each of the plurality of RO groups serves as a virtual RO corresponding to at least one additional request message preamble.

[0247] Aspect 60: The method of any one of Aspects 51-59, wherein at least one additional request message preamble comprises a preamble sequence, and wherein receiving at least one additional request message preamble comprises receiving the preamble sequence in multiple transmissions.

[0248] Aspect 61: A method of any one of Aspects 51-60, wherein at least one additional request message preamble comprises multiple preamble sequences, wherein each preamble sequence in the multiple preamble sequences is linked to each other preamble sequence in the multiple sequences, and wherein receiving at least one additional request message preamble comprises receiving each preamble sequence in the multiple preamble sequences in a corresponding one of the multiple transmissions.

[0249] Aspect 62: The method of Aspect 61, wherein each preamble sequence in the plurality of preamble sequences is linked with each other preamble sequence in the plurality of sequences based at least in part on at least one of: a wireless communication standard, a configuration sent to the UE, or a combination thereof.

[0250] Aspect 63: The method of Aspect 61 or 62, wherein the plurality of preamble code sequences include a subset of a set of preamble code sequences, and the method further comprises sending a configuration of the subset of the set of preamble code sequences to the UE.

[0251] Aspect 64: The method of Aspect 63, wherein the configuration of the subset of the preamble code sequence set is carried in the remaining minimum system information (RMSI).

[0252] Aspect 65: A method of any one of Aspects 48-64, wherein the initial request message includes an initial mapping of an initial RACH opportunity (RO) to an initial set of physical uplink shared channel (PUSCH) resources, and wherein the method further comprises receiving an additional request message based on an additional mapping of an additional RO to an additional set of PUSCH resources, wherein the additional request message corresponds to an alternative two-step RACH process.

[0253] Aspect 66: The method of Aspect 65, wherein receiving the initial request message includes receiving an initial uplink reference signal (RS) using an initial set of PUSCH resources, and wherein the method further includes receiving an additional uplink RS using an additional set of PUSCH resources, wherein the additional uplink RS is used to facilitate beam refinement associated with a base station, and wherein the additional uplink RS corresponds to an alternative two-step RACH process.

[0254] Aspect 67: A method of any one of Aspects 48-66, wherein receiving an initial request message includes receiving an initial request message based on an initial mapping of an initial RACH opportunity (RO) to an initial set of physical uplink shared channel (PUSCH) resources, and wherein the method further includes receiving multiple additional request messages based on additional mappings of multiple additional ROs to multiple additional PUSCH resource sets, wherein the multiple additional request messages correspond to an alternative two-step RACH process.

[0255] Aspect 68: The method of Aspect 67, wherein the additional mapping comprises mapping of four additional ROs to two sets of additional PUSCH resources.

[0256] Aspect 69: The method of Aspect 67 or 68, further comprising sending an indication of a time domain offset between at least one of the multiple additional ROs and at least one set of the multiple additional PUSCH resource sets to which the at least one of the multiple additional ROs is mapped.

[0257] Aspect 70: The method of Aspect 69, wherein at least one RO of the plurality of additional ROs comprises a first RO to occur among the plurality of additional ROs.

[0258] Aspect 71: The method of Aspect 69, wherein at least one RO of the plurality of additional ROs further comprises a third RO to be occurred among the plurality of additional ROs.

[0259] Aspect 72: The method of any one of Aspects 69-71, wherein the time domain offset comprises a time slot offset.

[0260] Aspect 73: The method of any one of Aspects 67-72 further comprises sending an indication of a frequency domain offset between at least one additional RO of the plurality of additional ROs and at least one set of at least one RO of the plurality of additional PUSCH resource sets to which the plurality of additional ROs are mapped.

[0261] Aspect 74: The method of Aspect 73, wherein at least one RO of the plurality of additional ROs comprises a first RO to occur among the plurality of additional ROs.

[0262] Aspect 75: The method of Aspect 73, wherein at least one RO of the plurality of additional ROs further comprises a third RO to be occurred among the plurality of additional ROs.

[0263] Aspect 76: The method of any one of Aspects 73-75, wherein the frequency domain offset comprises a subcarrier offset.

[0264] Aspect 77: The method of any one of Aspects 48-76, further comprising sending an additional response message corresponding to the additional request message of the alternative two-step RACH procedure.

[0265] Aspect 78: The method of Aspect 77, wherein the additional response message is sent using multiple monitoring opportunities corresponding to multiple physical downlink control channel (PDCCH) monitoring candidates.

[0266] Aspect 79: The method of Aspect 78, wherein each of the plurality of monitoring opportunities comprises an additional response message.

[0267] Aspect 80: The method of Aspect 78 or 79, wherein each of the multiple PDCCH monitoring candidates indicates at least one of: an index associated with an additional response message, a specific position in the search space corresponding to each monitoring opportunity associated with the PDCCH monitoring candidate, or a combination thereof.

[0268] Aspect 81: The method of any one of Aspects 78-80, wherein the plurality of PDCCH monitoring candidates are associated with a plurality of time slots.

[0269] Aspect 82: The method of any one of Aspects 78-81, wherein the plurality of monitoring opportunities comprises a plurality of groups of monitoring opportunities, each group of monitoring opportunities in the plurality of groups of monitoring opportunities comprising a plurality of consecutive monitoring opportunities corresponding to a plurality of time slots having an associated plurality of control resource sets (CORESETs).

[0270] Aspect 83: The method of Aspect 82, wherein a plurality of CORESETs are used as virtual monitoring opportunities corresponding to additional response messages.

[0271] Aspect 84: The method of any one of Aspects 48-83, wherein the alternative two-step RACH procedure comprises an additional RAR window different from the initial RAR window.

[0272] Aspect 85: The method of any one of Aspects 48-84, wherein the initial RAR window has a first length and the additional RAR window has a second length different from the first length.

[0273] Aspect 86: The method of Aspect 85, further comprising sending the configuration of the first length and the second length in the remaining minimum system information (RMSI).

[0274] Aspect 87: The method of Aspect 84, wherein the length of the initial RAR window is the same as the length of the additional RAR window.

[0275] Aspect 88: A method of any of Aspects 84-87, wherein the initial two-step RACH process includes an initial offset between sending an initial request message and a start time of an initial RAR window; and wherein the alternative two-step RACH process includes an additional offset between sending an additional request message and a start time of an additional RAR window, wherein the additional offset may be different from the initial offset.

[0276] Aspect 89: The method of Aspects 48-88, wherein the length of the initial RAR window is based at least in part on one or more measurements associated with the signal.

[0277] Aspect 90: The method of Aspect 89, wherein one or more measurements include a synchronization signal block (SSB)-based reference signal received power (RSRP), and wherein, based at least in part on the SSB-based RSRP satisfying a threshold, the length of the initial RAR window may be shorter than the length of the additional RAR window.

[0278] Aspect 91: A method of any one of Aspects 48-90, wherein the initial two-step RACH process includes initial downlink control information (DCI) carried by an initial response message, the initial DCI having a first size, and wherein the alternative two-step RACH process includes additional DCI carried by an additional response message, wherein the additional DCI has a second size different from the first size.

[0279] Aspect 92: A method of any one of Aspects 48-91, wherein the initial two-step RACH process includes initial downlink control information (DCI) carried by an initial response message, the initial DCI including content associated with a first interpretation of the UE; and wherein the alternative two-step RACH process includes an additional DCI carried by an additional response message, the additional DCI including content associated with a second interpretation of the UE, wherein the second interpretation is different from the first interpretation.

[0280] Aspect 93: 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 cause the apparatus to perform the method of one or more aspects of aspects 1-47.

[0281] Aspect 94: An apparatus for wireless communication, comprising a memory and one or more processors coupled to the memory, the memory and the one or more processors configured to perform the method of one or more aspects of aspects 1-47.

[0282] Aspect 95: An apparatus for wireless communication, comprising at least one unit for performing the method of one or more aspects of aspects 1-47.

[0283] Aspect 96: 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 1-47.

[0284] Aspect 97: A non-transitory computer-readable medium storing an instruction set for wireless communication, the instruction set comprising one or more instructions that, when executed by one or more processors of a device, cause the device to perform one or more methods of aspects 1-47.

[0285] Aspect 98: 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 cause the apparatus to perform the method of one or more aspects of aspects 48-92.

[0286] Aspect 99: An apparatus for wireless communication, comprising a memory and one or more processors coupled to the memory, the memory and the one or more processors configured to perform the method of one or more aspects of aspects 48-92.

[0287] Aspect 100: An apparatus for wireless communication, comprising at least one means for performing the method of one or more of aspects 48-92.

[0288] Aspect 101: 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 48-92.

[0289] Aspect 102: A non-transitory computer-readable medium storing an instruction set for wireless communication, the instruction set comprising one or more instructions that, when executed by one or more processors of a device, cause the device to perform one or more of the methods of aspects 48-92.

[0290] 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 may be made in light of the above disclosure or may be acquired from practice of these aspects.

[0291] As used herein, the term "component" is intended to be broadly interpreted as a combination of hardware and / or hardware and software. "Software" should be broadly interpreted as 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, and other examples, whether referred to as software, firmware, middleware, microcode, hardware description language or other. As used herein, the processor is implemented with a combination of hardware and / or hardware and software. Obviously, 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 specific software codes, and it should be understood that software and hardware can be designed to implement the system and / or method based at least in part on the description herein.

[0292] As used herein, satisfying a threshold refers 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.

[0293] Even if a specific combination of features is recorded in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features can be combined in a manner that is not specifically recorded in the claims and / or disclosed in the specification. Although each dependent claim listed below may only directly depend on one claim, the disclosure of various aspects includes the combination of each dependent claim with each other claim in the claim set. As used herein, the phrase "at least one" referring to a 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 with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc and ccc or any other order of a, b and c).

[0294] Unless explicitly stated, any element, action or instruction used herein should not be interpreted as critical or necessary. In addition, as used herein, the articles "a" 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 "the" is intended to include one or more items quoted in conjunction with the article "the", and can be used interchangeably with "one or more". In addition, as used herein, the terms "set" and "group" are intended to include one or more items (e.g., related items, unrelated items, or a combination of related items and unrelated items), and can be used interchangeably with "one or more". If only one item is intended to be used, the phrase "only one" or similar language is used. In addition, as used herein, the terms "has", "have", "having" etc. are intended to be open terms. In addition, unless explicitly stated otherwise, the phrase "based on" is intended to mean "based at least in part on". Furthermore, as used herein, the term "or" when used in a serial form is intended to be inclusive and can be used interchangeably with "and / or" unless expressly stated otherwise (eg, if used in combination with "either" or "only one of").

Claims

1. A user equipment (UE) for wireless communication, comprising: one or more memories; as well as One or more processors coupled to the one or more memories, configured to: An initial two-step random access channel (RACH) attempt is performed by sending an initial request message for an initial RACH procedure to a network entity, Wherein, in order to send the initial request message, the one or more processors are configured to send an initial request message preamble according to an initial transmission process; and performing an additional RACH attempt using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to the initial request message for the two-step RACH procedure was not received during an initial random access response (RAR) window, wherein, to perform the additional RACH attempt using the alternative two-step RACH procedure, the one or more processors are configured to send at least one additional request message preamble according to an additional transmission procedure, the additional transmission procedure being different from the initial transmission procedure, The at least one additional request message preamble comprises a plurality of preamble sequences, and Wherein, each preamble sequence of the plurality of preamble sequences is linked to each other preamble sequence of the plurality of preamble sequences.

2. The UE according to claim 1, wherein: The one or more processors are further configured to: obtaining one or more measurements associated with the signal, The UE is to perform the additional RACH attempt based at least in part on the one or more measurements.

3. The UE according to claim 2, wherein: The one or more measurements include a reference signal received power (RSRP) based on a synchronization signal block (SSB), and The UE is to perform the additional RACH attempt based at least in part on determining that the SSB-based RSRP satisfies a threshold.

4. The UE according to claim 1, wherein: The additional transmission process includes a coverage enhancement transmission process.

5. The UE according to claim 1, wherein: The initial transmission process is performed using a first transmission power, and wherein the additional transmission process is performed using a second transmission power higher than the first transmission power.

6. The UE according to claim 1, wherein: The initial transmission process is performed using a first subset of preamble sequences in a set of preamble sequences, and wherein the additional transmission process is performed using a second subset of preamble sequences in the set of preamble sequences, wherein the second subset of preamble sequences is different from the first subset of preamble sequences.

7. The UE according to claim 1, wherein: The initial transmission process is performed using a first subset of RACH opportunities (ROs) in a set of ROs, and wherein the additional transmission process is performed using a second subset of ROs in the set of ROs, wherein the second subset of ROs is different from the first subset of ROs.

8. The UE according to claim 1, wherein: The initial transmission process is performed using an initial request message preamble format, and wherein the additional transmission process is performed using at least one additional request message preamble format, wherein the at least one additional request message preamble format is different from the initial request message preamble format.

9. The UE according to claim 1, wherein: The additional transmission process is performed using multiple transmissions, wherein the multiple transmissions correspond to multiple RACH opportunities (ROs).

10. The UE according to claim 9, wherein: Each of the multiple transmissions is associated with the same synchronization signal block beam.

11. The UE according to claim 9, wherein: The plurality of ROs include a plurality of RO groups, wherein each of the plurality of RO groups serves as a virtual RO corresponding to the at least one additional request message preamble.

12. The UE according to claim 1, wherein: Sending the at least one additional request message preamble includes sending a preamble sequence of the plurality of preamble sequences in a plurality of transmissions.

13. The UE according to claim 1, wherein: Transmitting the at least one additional request message preamble includes transmitting each preamble sequence of the plurality of preamble sequences in a corresponding one of the plurality of transmissions.

14. The UE according to claim 1, wherein: Each preamble sequence in the plurality of preamble sequences is linked with each other preamble sequence in the plurality of preamble sequences based at least in part on at least one of: Wireless communication standards, a configuration received from said network entity, or Its combination.

15. The UE according to claim 1, wherein: The plurality of preamble sequences comprises a subset of a set of preamble sequences, and wherein the one or more processors are further configured to receive a configuration of the subset of the set of preamble sequences from the network entity.

16. The UE according to claim 15, wherein: The configuration of the subset of the set of preamble sequences is carried in remaining minimum system information.

17. The UE according to claim 1, wherein: To send the initial request message, the one or more processors are configured to send the initial request message according to an initial mapping of initial RACH opportunities (ROs) to an initial set of physical uplink shared channel (PUSCH) resources, and Wherein, to perform the alternative two-step RACH procedure, the one or more processors are configured to send an additional request message according to an additional mapping of additional ROs to additional sets of PUSCH resources.

18. The UE according to claim 17, wherein: To send the initial request message, the one or more processors are configured to send an initial uplink reference signal (RS) using the initial set of PUSCH resources, and Wherein performing the alternative two-step RACH procedure includes using the additional set of PUSCH resources to send additional uplink RSs, wherein the additional uplink RSs are used to facilitate beam refinement associated with the network entity.

19. The UE according to claim 1, wherein: To send the initial request message, the one or more processors are configured to send the initial request message according to an initial mapping of initial RACH opportunities (ROs) to an initial set of physical uplink shared channel (PUSCH) resources, and Wherein, to perform the alternative two-step RACH procedure, the one or more processors are configured to send multiple additional request messages according to additional mappings of multiple additional ROs to multiple additional PUSCH resource sets.

20. The UE according to claim 19, wherein: The one or more processors are further configured to receive an indication of a time domain offset between at least one additional RO of the plurality of additional ROs and at least one additional PUSCH resource set of a plurality of additional PUSCH resource sets to which the at least one additional RO of the plurality of additional ROs is mapped.

21. The UE according to claim 19, wherein: The one or more processors are further configured to receive an indication of a frequency domain offset between at least one additional RO of the plurality of additional ROs and at least one additional PUSCH resource set of the plurality of additional PUSCH resource sets to which the at least one additional RO of the plurality of additional ROs is mapped.

22. The UE according to claim 1, wherein: To perform the initial two-step RACH procedure, the one or more processors are configured to monitor an initial physical downlink control channel (PDCCH) for the initial response message according to an initial reception procedure; and Wherein, performing the alternative two-step RACH procedure includes monitoring an additional PDCCH for an additional response message corresponding to an additional request message according to an additional reception procedure, wherein the additional reception procedure is different from the initial reception procedure.

23. The UE according to claim 22, wherein: The additional reception process includes monitoring a plurality of PDCCH monitoring candidates associated with a plurality of monitoring opportunities.

24. The UE according to claim 23, wherein: Each monitoring opportunity of the plurality of monitoring opportunities includes the additional response message.

25. The UE according to claim 23, wherein: Each of the plurality of PDCCH monitoring candidates indicates at least one of the following: an index associated with the additional response message, a specific position in the search space corresponding to each monitoring opportunity associated with the PDCCH monitoring candidate, or Its combination.

26. The UE according to claim 23, wherein: The plurality of PDCCH monitoring candidates are associated with a plurality of time slots.

27. A network entity for wireless communication, comprising: one or more memories; as well as One or more processors coupled to the one or more memories, configured to: receiving an initial request message for an initial two-step random access channel (RACH) procedure from a user equipment (UE), wherein the initial request message corresponds to an initial RACH attempt, and Wherein, in order to receive the initial request message, the one or more processors are configured to receive an initial request message preamble sent according to an initial transmission process; and receiving an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed by the UE based at least in part on the UE not receiving an initial response message corresponding to the initial request message during an initial random access response (RAR) window, wherein, in order to receive the additional request message, the one or more processors are configured to receive at least one additional request message preamble sent according to an additional transmission process, the additional transmission process being different from the initial transmission process, The at least one additional request message preamble comprises a plurality of preamble sequences, and Wherein, each preamble sequence of the plurality of preamble sequences is linked to each other preamble sequence of the plurality of preamble sequences.

28. The network entity according to claim 27, wherein: To receive the at least one additional request message preamble, the one or more processors are further configured to: Each preamble sequence of the plurality of preamble sequences is received in a corresponding one of the plurality of transmissions.

29. A method of wireless communication performed by a user equipment (UE), comprising: An initial two-step random access channel (RACH) attempt is performed by sending an initial request message for an initial RACH procedure to a network entity, Wherein, sending the initial request message includes sending an initial request message preamble according to an initial transmission process; and performing an additional RACH attempt using an alternative two-step RACH procedure based at least in part on determining that an initial response message corresponding to the initial request message for the two-step RACH procedure was not received during an initial random access response (RAR) window, wherein performing the additional RACH attempt using the alternative two-step RACH procedure comprises sending at least one additional request message preamble according to an additional transmission procedure, the additional transmission procedure being different from the initial transmission procedure, The at least one additional request message preamble comprises a plurality of preamble sequences, and Wherein, each preamble sequence of the plurality of preamble sequences is linked to each other preamble sequence of the plurality of preamble sequences.

30. A wireless communication method performed by a network entity, comprising: receiving an initial request message for an initial two-step random access channel (RACH) procedure from a user equipment (UE), wherein the initial request message corresponds to an initial RACH attempt, Wherein, receiving the initial request message includes receiving an initial request message preamble code sent according to an initial transmission process; and receiving an additional request message for an alternative two-step RACH procedure, wherein the additional request message corresponds to an additional RACH attempt performed by the UE based at least in part on the UE not receiving an initial response message corresponding to the initial request message during an initial random access response (RAR) window, wherein receiving the additional request message comprises receiving at least one additional request message preamble sent according to an additional transmission process, the additional transmission process being different from the initial transmission process, The at least one additional request message preamble comprises a plurality of preamble sequences, and Wherein, each preamble sequence of the plurality of preamble sequences is linked to each other preamble sequence of the plurality of preamble sequences.

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