Dynamic RACH MSG1 / MSGA Configuration

Abstract

A user equipment (UE) and a base station can perform a random access procedure based on a dynamic physical random access channel (PRACH) configuration. The UE can determine a first PRACH configuration, e.g., based on system information. The UE can determine a second PRACH configuration, e.g., based on a dynamic configuration message. The UE can determine to follow the second PRACH configuration based on a current time or the dynamic configuration message. The UE can transmit a first message of a random access (RACH) procedure based on the second PRACH configuration.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 038,518, filed June 12, 2020, entitled “DYNAMICRACH MSG1 / MSGA CONFIGURATION”; and U.S. Patent Application No. 17 / 344,224, filed June 10, 2021, entitled “DYNAMIC RACH MSG1 / MSGA CONFIGURATION”, which has been assigned to the assignee of this application and is incorporated herein by reference in its entirety. Technical Field

[0003] In summary, this disclosure relates to communication systems, and more specifically, to the dynamic configuration of the first message during a random access procedure. Background Technology

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunications services, such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. 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, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different wireless devices to communicate at the city, country, region, and even global levels. An example telecommunications standard is 5G New Radio (NR). 5G NR is part of the continuous evolution of mobile broadband released by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT),) and others. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Some aspects of 5G NR can be based on the 4G Long Term Evolution (LTE) standard. There is a need for further improvements to 5G NR technology. These improvements can also be applied to other multiple access technologies and telecommunications standards that adopt them. Summary of the Invention

[0006] The following provides a brief overview of one or more aspects to offer a basic understanding of such aspects. This overview is not a comprehensive summary of all anticipated aspects, and is neither intended to identify key or important elements of all aspects, nor to depict the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed descriptions that follow.

[0007] Wireless communication may include a random access (RACH) procedure, which allows a user equipment (UE) to initiate or resume communication with a base station. In some scenarios, a large number of RedCap and / or Internet of Things (IoT) devices may connect to the same cell and attempt to access the network using the RACH procedure at approximately the same time. The Physical Random Access Channel (PRACH) may become congested or overloaded, which can impact UE performance.

[0008] This disclosure provides dynamic RACH configuration. For example, RACH parameters used for a cell can be temporarily adjusted to meet the expected needs of the device performing the RACH procedure. Therefore, dynamic RACH configuration can reduce the rate of failed RACH procedures and improve the device's ability to access the network.

[0009] In one aspect of this disclosure, a method, a non-transitory computer-readable medium, and an apparatus (e.g., a UE) are provided. The method may include: determining a first PRACH configuration. The method may include: determining a second PRACH configuration. The method may include: determining compliance with the second PRACH configuration based on a current time or a dynamic configuration message. The method may include: sending a first message for a RACH procedure based on the second PRACH configuration.

[0010] In some implementations, determining the second PRACH configuration includes receiving the dynamic configuration message that includes a PRACH configuration update.

[0011] In some implementations, the dynamic configuration message is one of a downlink control information (DCI), a media access control (MAC) control element (CE), or a paging message.

[0012] In some implementations, the second PRACH configuration remains valid until a second PRACH configuration update is received.

[0013] In some implementations, the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0014] In some implementations, the PRACH configuration update includes a set of PRACH configuration parameters.

[0015] In some implementations, the PRACH configuration update indicates the configured PRACH configuration.

[0016] In some implementations, the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0017] In some implementations, the first PRACH configuration is based on a system information block.

[0018] In some implementations, the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0019] In some implementations, the second PRACH configuration is used for a 4-step RACH process or a 2-step RACH process.

[0020] In one aspect of this disclosure, a method, a non-transitory computer-readable medium, and an apparatus (e.g., a base station) are provided. The method may include: transmitting system information indicating a first PRACH configuration. The method may include: determining, based on the current time, that a second PRACH configuration is applicable. The method may include: receiving a first message for a RACH procedure based on the second PRACH configuration.

[0021] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and drawings set forth certain illustrative features of one or more aspects in detail. However, these features indicate only some of the various ways in which the principles of each aspect may be employed, and this specification is intended to include all such aspects and their equivalents. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating an example of a wireless communication system and an access network.

[0023] Figure 2A This is a schematic diagram showing an example of the first 5G NR frame.

[0024] Figure 2B This is a schematic diagram illustrating an example of a DL channel within a 5G NR subframe.

[0025] Figure 2C This is a schematic diagram illustrating an example of a second 5G NR frame.

[0026] Figure 2D This is a schematic diagram illustrating an example of a 5G NR subframe.

[0027] Figure 3 This is a schematic diagram illustrating an example of a base station and user equipment (UE) in an access network.

[0028] Figure 4 This is a schematic diagram illustrating an example message exchange of a four-step random access procedure between a base station and a UE in an access network.

[0029] Figure 5 This is a schematic diagram illustrating an example message exchange of a two-step random access procedure between a base station and a UE in an access network.

[0030] Figure 6 This is a flowchart of a wireless communication method performed by the UE.

[0031] Figure 7 This is a conceptual data flow diagram illustrating the data flow between different components in an example UE.

[0032] Figure 8 This is a flowchart of a wireless communication method performed by a base station.

[0033] Figure 9 This is a conceptual data flow diagram illustrating the data flow between different components in an example base station. Detailed Implementation

[0034] The detailed description below, taken in conjunction with the accompanying drawings, is intended as a description of various configurations and not as representing only the configurations in which the concepts described herein can be practiced. For the purpose of providing a comprehensive understanding of the various concepts, the detailed description includes specific details. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, well-known structures and components are shown in the form of block diagrams in order to avoid obscuring such concepts.

[0035] Several aspects of a telecommunications system will now be described with reference to various apparatuses and methods. These apparatuses and methods will be described in detail below and illustrated in the accompanying drawings by way of various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements”). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the system as a whole.

[0036] By way of example, an element, or any part of an element, or any combination of elements, can be implemented as a “processing system” including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, system-on-a-chip (SoCs), baseband processors, field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described herein. One or more processors in a processing system can execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other names, software should be broadly interpreted as meaning instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc.

[0037] Accordingly, in one or more example embodiments, the described functionality may be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality may be stored or encoded as one or more instructions or code on a computer-readable medium. A computer-readable medium includes a computer storage medium. A computer-readable medium may be referred to as a non-transitory computer-readable medium. A storage medium may be any available medium that can be accessed by a computer. By way of example, and not limitation, such a computer-readable medium may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of computer-readable media of the types described above, or any other medium capable of storing computer-executable code in the form of instructions or data structures accessible by a computer.

[0038] Figure 1 This is a schematic diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a user interface unit (UE) 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Macro cells include base stations. Small cells include femtocells, picocells, and microcells.

[0039] In some aspects, UE 104 may include a UE random access component 140 configured to perform a random access procedure based on dynamically configured Physical Random Access Channel (PRACH) parameters. UE random access component 140 may include a system configuration component 142 configured to determine a first PRACH configuration. UE random access component 140 may include a dynamic configuration component 144 configured to determine a second PRACH configuration. UE random access component 140 may include a selection component 146 configured to determine compliance with the second PRACH configuration based on the current time or a dynamic configuration message. UE random access component 140 may include a preamble component 148 configured to send a first message for the RACH procedure based on the second PRACH configuration.

[0040] In some aspects, one or more base stations 102 / 180 may include a base station (BS) random access component 198 configured to receive the first message of the RACH procedure based on a dynamic PRACH configuration. For example... Figure 9 As shown, the BS random access component 198 may include a system information component 906, a selection component 908, and a preamble receiver component 912. The system information component 906 may be configured to transmit system information indicating a first PRACH configuration. The selection component 908 may be configured to determine, based on the current time, whether a second PRACH configuration is applicable. The preamble receiver component 912 may be configured to receive a first message of the RACH procedure based on the second PRACH configuration. The BS random access component 198 may optionally include a dynamic messaging component configured to transmit a dynamic configuration message including a PRACH configuration update in response to determining the second PRACH configuration.

[0041] Base station 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can be connected to EPC 160 via a first backhaul link 132 (e.g., S1 interface). Base station 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) can be connected to core network 190 via a second backhaul link 184. Among other functions, base station 102 can perform one or more of the following functions: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), user and device tracking, RAN information management (RIM), paging, location, and delivery of warning messages. Base stations 102 can communicate with each other directly or indirectly (e.g., via EPC 160 or core network 190) via a third backhaul link 134 (e.g., an X2 interface). The third backhaul link 134 can be wired or wireless.

[0042] Base station 102 can wirelessly communicate with UE 104. Each base station in base station 102 can provide communication coverage for a corresponding geographic coverage area 110. Overlapping geographic coverage areas 110 may exist. For example, small cell 102' may have a coverage area 110' that overlaps with the coverage areas 110 of one or more macro base stations 102. A network that includes both small cells and macro cells can be referred to as a heterogeneous network. The heterogeneous network may also include evolved home node B (eNB) (HeNB), which can provide services to a restricted group referred to as a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 may include uplink (UL) (also referred to as reverse link) transmission from UE 104 to base station 102 and / or downlink (DL) (also referred to as forward link) transmission from base station 102 to UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technologies, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be via one or more carriers. Base station 102 / UE 104 may use spectrum allocated in carrier aggregation for a total of up to Y x MHz (x component carriers) for transmission in each direction, with a bandwidth of up to Y MHz per carrier (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.). Carriers may be adjacent to each other or may not be adjacent to each other. Carrier allocation may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​compared to UL). Component carriers may include primary component carriers and one or more secondary component carriers. The primary component carrier may be referred to as the primary cell (PCell), and the secondary component carrier may be referred to as the secondary cell (SCell).

[0043] Some UEs 104 can communicate with each other using device-to-device (D2D) communication link 158. D2D communication link 158 can use DL / UL WWAN spectrum. D2D communication link 158 can use one or more sideline channels, such as the Physical Sideline Broadcast Channel (PSBCH), Physical Sideline Discovery Channel (PSDCH), Physical Sideline Shared Channel (PSSCH), and Physical Sideline Control Channel (PSCCH). D2D communication can be achieved through various wireless D2D communication systems such as FlashLinQ, WiMedia, Bluetooth, Zipline, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0044] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a free channel assessment (CCA) before communication to determine whether the channel is available.

[0045] Small cell 102' can operate in licensed and / or unlicensed spectrum. When operating in unlicensed spectrum, small cell 102' can employ NR and use the same 5 GHz unlicensed spectrum as used by Wi-Fi AP 150. Small cell 102' employing NR in unlicensed spectrum can improve coverage of the access network and / or increase the capacity of the access network.

[0046] The electromagnetic spectrum is typically subdivided into various categories, bands, channels, etc., based on frequency / wavelength. In 5G NR, the two initial operating bands have been designated as frequency range names FR1 (410MHz-7.125GHz) and FR2 (24.25GHz-52.6GHz). Frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although a portion of FR1 is larger than 6GHz, FR1 is frequently (interchangeably) referred to as the “below 6GHz” band in various documents and articles. Similar naming issues sometimes occur with FR2, which is frequently (interchangeably) referred to as the “millimeter wave” band in documents and articles, although this is different from the extremely high frequency (EHF) band (30GHz-300GHz) designated as a “millimeter wave” band by the International Telecommunication Union (ITU).

[0047] Considering the foregoing, unless otherwise expressly stated, it should be understood that, as used herein, the terms "below 6 GHz," etc., can broadly refer to frequencies that are below 6 GHz, within FR1, or may include mid-band frequencies. Furthermore, unless otherwise expressly stated, it should be understood that, as used herein, the terms "millimeter wave," etc., can broadly refer to frequencies that may include mid-band frequencies, within FR2, or within the EHF band. Communication using millimeter wave RF bandwidth has extremely high path loss and short range. Millimeter wave base station 180 can utilize beamforming 182 with UE 104 to compensate for path loss and short range.

[0048] Base station 180 can transmit beamformed signals to UE 104 in one or more transmit directions 182'. UE 104 can receive beamformed signals from base station 180 in one or more receive directions 182'. UE 104 can also transmit beamformed signals to base station 180 in one or more transmit directions. Base station 180 can receive beamformed signals from UE 104 in one or more receive directions. Base station 180 / UE 104 can perform beam training to determine the optimal receive and transmit directions for each of base station 180 / UE 104. The transmit and receive directions for base station 180 can be the same or different. The transmit and receive directions for UE 104 can be the same or different.

[0049] EPC 160 may include Mobility Management Entity (MME) 162, other MMEs 164, Serving Gateway 166, Multimedia Broadcast Multicast Service (MBMS) Gateway 168, Broadcast Multicast Service Center (BM-SC) 170, and Packet Data Network (PDN) Gateway 172. MME 162 may communicate with Home Subscriber Server (HSS) 174. MME 162 is the control node that handles signaling between UE 104 and EPC 160. Typically, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through Serving Gateway 166, which is itself connected to PDN Gateway 172. PDN Gateway 172 provides IP address allocation and other functions to the UE. PDN Gateway 172 and BM-SC 170 are connected to IP Service 176. IP Service 176 may include the Internet, intranet, IP Multimedia Subsystem (IMS), PS streaming service, and / or other IP services. The BM-SC 170 can provide functions for MBMS user service provisioning and delivery. The BM-SC 170 can serve as an entry point for MBMS transmission to content providers, can be used to authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and can be used to schedule MBMS transmissions. The MBMS gateway 168 can be used to distribute MBMS services to base stations 102 belonging to areas of a Multicast-Broadcast Single Frequency Network (MBSFN) that broadcasts specific services, and can be responsible for session management (start / stop) and collecting billing information related to eMBMS.

[0050] Core network 190 may include Access and Mobility Management Functions (AMF) 192, other AMFs 193, Session Management Functions (SMF) 194, and User Plane Functions (UPF) 195. AMF 192 can communicate with Unified Data Management (UDM) 196. AMF 192 is the control node that processes signaling between UE 104 and core network 190. Typically, AMF 192 provides QoS streaming and session management. All user Internet Protocol (IP) packets are transmitted via UPF 195. UPF 195 provides UE IP address allocation and other functions. UPF 195 connects to IP service 197. IP service 197 may include the Internet, intranet, IP Multimedia Subsystem (IMS), PS streaming service, and / or other IP services.

[0051] Base stations may include and / or be referred to as gNB, Node B, eNB, access point, base transceiver, radio base station, radio transceiver, transceiver function, Basic Services Set (BSS), Extended Services Set (ESS), Transmitter Receiver Point (TRP), or some other suitable term. Base station 102 provides access to EPC 160 or core network 190 for UE 104. Examples of UE 104 include cellular phones, smartphones, Session Initiation Protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radio units, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, gaming consoles, tablet devices, smart devices, wearable devices, vehicles, electricity meters, air pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other similarly functional devices. Some UE 104 devices may be referred to as IoT devices (e.g., parking meters, air pumps, ovens, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, mobile station, user station, mobile unit, user unit, radio unit, remote unit, mobile device, radio device, wireless communication device, remote device, mobile user station, access terminal, mobile terminal, radio terminal, remote terminal, handheld device, user agent, mobile client, client, or any other suitable term.

[0052] Although the following description may focus on 5G NR, the concepts described herein can be applied to other similar areas, such as LTE, LTE-A, CDMA, GSM or other wireless technologies.

[0053] Figure 2A This is a schematic diagram 200 showing an example of the first subframe within a 5G NR frame structure. Figure 2B This is a schematic diagram 230 showing an example of a DL channel within a 5G NR subframe. Figure 2C This is a schematic diagram 250 showing an example of a second subframe within a 5G NR frame structure. Figure 2D This is a schematic diagram 280 illustrating an example of a UL channel within a 5G NR subframe. The 5G NR frame structure can be FDD (where, for a specific set of subcarriers (carrier system bandwidth), subframes within that set are dedicated to either DL or UL), or it can be TDD (where, for a specific set of subcarriers (carrier system bandwidth), subframes within that set are dedicated to both DL and UL). In the process of... Figure 2A , 2C In the provided example, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (mostly DL), where D is DL, U is UL, and X is flexible between DL / UL, and subframe 3 is configured with slot format 34 (mostly UL). Although subframes 3 and 4 are shown as having slot formats 34 and 28, respectively, any particular subframe can be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2-61 include a mixture of DL, UL, and flexible symbols. The UE is configured with a slot format via the received Slot Format Indicator (SFI) (dynamically configured via DL Control Information (DCI) or semi-statically / statically configured via Radio Resource Control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0054] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10 ms) can be divided into 10 equal-sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include micro-time slots, which may include 7, 4, or 2 symbols. Depending on the time slot configuration, each time slot may include 7 or 14 symbols. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. Symbols on the DL can be Cyclic Prefix (CP) OFDM (CP-OFDM) symbols. Symbols on the UL can be CP-OFDM symbols (for high-throughput scenarios) or Discrete Fourier Transform (DFT) Spread Spectrum OFDM (DFT-s-OFDM) symbols (also known as Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols) (for power-constrained scenarios; limited to single-stream transmission). The number of time slots within a subframe is based on the time slot configuration and the numbering scheme. For slot configuration 0, different digital schemes μ0 to 5 allow 1, 2, 4, 8 and 16 and 32 slots per subframe, respectively. For slot configuration 1, different digital schemes 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Correspondingly, for slot configuration 0 and digital scheme μ, there are 14 symbols / slot and 2... μ Each time slot / subframe. Subcarrier spacing and symbol length / duration are functions of the digital scheme. Subcarrier spacing can be equal to 2. μ *15kHz, where μ is the digital scheme from 0 to 5. Accordingly, digital scheme μ = 0 has a subcarrier spacing of 15kHz, and digital scheme μ = 5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figures 2A-2D Examples are provided for slot configuration 0 (with 14 symbols per slot) and digital scheme μ=2 (with 4 slots per subframe). The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

[0055] A resource grid can be used to represent the frame structure. Each time slot includes a resource block (RB) (also called a physical RB (PRB)), which is extended by 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0056] As in Figure 2A As shown, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include a demodulated RS (DM-RS) for channel estimation at the UE (indicated as R for a specific configuration). xHowever, other DM-RS configurations are possible) and Channel State Information Reference Signal (CSI-RS). RS can also include Beam Measurement RS (BRS), Beam Refinement RS (BRRS), and Phase Tracking RS (PT-RS).

[0057] Figure 2B Examples of various DL channels within a subframe of a frame are shown. The Physical Downlink Control Channel (PDCCH) carries the DCI within one or more Control Channel Elements (CCEs), each CCE comprising nine RE Groups (REGs), each REG comprising four consecutive REs in an OFDM symbol. The Primary Synchronization Signal (PSS) may be located within symbol 2 of a specific subframe of the frame. The PSS is used by UE104 to determine subframe / symbol timing and physical layer identification. The Secondary Synchronization Signal (SSS) may be located within symbol 4 of a specific subframe of the frame. The SSS is used by the UE to determine the Physical Layer Cell Identity Group Number and radio frame timing. Based on the Physical Layer Identity and Physical Layer Cell Identity Group Number, the UE can determine the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DM-RS. The Physical Broadcast Channel (PBCH) carrying the Primary Information Block (MIB) may logically be grouped with the PSS and SSS to form a Synchronization Signal (SS) / PBCH block. The MIB provides the number of RBs in the system bandwidth and the System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information (such as System Information Blocks (SIBs)) that are not transmitted via the PBCH, and paging messages.

[0058] As in Figure 2C As shown, some of the REs in the diagram carry DM-RS for channel estimation at the base station (indicated as R for a specific configuration, but other DM-RS configurations are possible). The UE can transmit DM-RS for the Physical Uplink Control Channel (PUCCH) and DM-RS for the Physical Uplink Shared Channel (PUSCH). The PUSCH DM-RS can be transmitted in the first one or two symbols preceding the PUSCH. The PUCCH DM-RS can be transmitted in different configurations depending on whether a short or long PUCCH is transmitted and the specific PUCCH format used. The UE can transmit a Sounding Reference Signal (SRS). The SRS can be transmitted in the last symbol of a subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the combs. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0059] Figure 2DExamples of various UL channels within a subframe of a frame are shown. The PUCCH can be positioned as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and HARQ-ACK / NACK feedback. The PUSCH carries data and can also be used to carry buffer status reports (BSR), power headroom reports (PHR), and / or UCI.

[0060] Figure 3 This is a block diagram illustrating communication between base station 310 and UE 350 in the access network. In the DL, IP packets from EPC 160 can be provided to controller / processor 375. Controller / processor 375 implements Layer 3 and Layer 2 functions. Layer 3 includes the Radio Resource Control (RRC) layer, and Layer 2 includes the Serving Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, and Media Access Control (MAC) layer. The controller / processor 375 provides: RRC layer functions associated with: broadcasting system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-Radio Access Technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with: header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with: transmission of upper-layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with: mapping between logical channels and transport channels, multiplexing of MAC SDUs to transport blocks (TBs), and MAC... SDU performs demultiplexing of TB, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0061] Transmit (TX) processor 316 and receive (RX) processor 370 implement Layer 1 functions associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection of the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. TX processor 316 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase phase shift keying (M-PSK), and M-order quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols can then be divided into parallel streams. Each stream can then be mapped to OFDM subcarriers, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domains, and then combined using inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from channel estimator 374 can be used to determine coding and modulation schemes and for spatial processing. The channel estimates can be derived from reference signals transmitted by UE 350 and / or channel condition feedback. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX can use the corresponding spatial stream to modulate an RF carrier for transmission.

[0062] At UE 350, each receiver 354RX receives signals via its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and RX processor 356 implement Layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for UE 350. If multiple spatial streams are destined for UE 350, they can be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then uses a Fast Fourier Transform (FFT) to transform the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal consists of a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, along with a reference signal, are recovered and demodulated by determining the most probable signal constellation point transmitted by base station 310. These soft decisions can be based on a channel estimate calculated by channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by base station 310 on the physical channel. The data and control signals are then provided to controller / processor 359, which implements Layer 3 and Layer 2 functions.

[0063] The controller / processor 359 may be associated with a memory 360 that stores program code and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between the transport and logical channels to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operation.

[0064] Similar to the functions described in conjunction with DL transmissions performed by base station 310, controller / processor 359 provides: RRC layer functions associated with: system information (e.g., MIB, SIB) acquisition, RRC connection and measurement reporting; PDCP layer functions associated with: header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with: transmission of upper-layer PDUs, error correction via ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs and reordering of RLC data PDUs; and MAC layer functions associated with: mapping between logical channels and transport channels, multiplexing of MAC SDUs to TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority processing and logical channel prioritization.

[0065] The channel estimate derived by channel estimator 358 from a reference signal or feedback transmitted by base station 310 can be used by TX processor 368 to select an appropriate modulation and coding scheme and to facilitate spatial processing. The spatial stream generated by TX processor 368 can be provided to different antennas 352 via a separate transmitter 354TX. Each transmitter 354TX can use the corresponding spatial stream to modulate an RF carrier for transmission.

[0066] UL transmission at base station 310 is handled in a manner similar to that described for the receiver functions integrated at UE 350. Each receiver 318RX receives signals via its corresponding antenna 320. Each receiver 318RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0067] The controller / processor 375 may be associated with a memory 376 that stores program code and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between the transport channel and the logical channel to recover IP packets from the UE 350. IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operation.

[0068] At least one of the TX processor 368, RX processor 356, and controller / processor 359 can be configured to perform coupled operations. Figure 1 Various aspects of the UE random access component 140.

[0069] At least one of the TX processor 316, RX processor 370, and controller / processor 375 can be configured to perform coupling. Figure 1 The various aspects of the BS random access component 198.

[0070] Capability-degraded (RedCap) devices and / or IoT devices can be used in a variety of scenarios, including wearables, industrial wireless sensors, and video surveillance. Some of these scenarios may involve stationary devices. There may be a relatively large number of such devices located within a cell. More specifically, a large number of such devices may share the cell's transmit beam. For example, multiple devices located close to each other may choose the same SSB as the strongest transmit beam. For example, in one use case, co-located cameras or industrial sensors may be scheduled to upload data to the network at a specific time. Such devices may attempt to perform the RACH process using the same beam, which could overload PRACH resources. As another example, parking facilities for personal vehicles such as bicycles or scooters may include many devices attempting to access the network at specific times (e.g., peak hours).

[0071] Multiple devices attempting to perform the RACH procedure simultaneously can overload RACH resources. For example, if multiple UEs select the same RACH preamble, conflicts may occur, and the RACH procedure for one or more UEs may fail. Typically, PRACH parameters are statically configured. For example, the base station can broadcast the RACH configuration via system information. For instance, each UE can acquire the cell by reading the Synchronization Signal Block (SSB) and the First System Information Block (SIB1). SIB1 provides initial access-related parameters. In some cases, the base station can reconfigure the PRACH parameters using RRC messages, but RRC signaling may not be available for UEs in idle mode.

[0072] In one aspect, the base station can dynamically configure one or more UEs to temporarily use a second PRACH configuration. For example, the base station can send a dynamic configuration message that includes a PRACH configuration update. The PRACH configuration update may be valid for a specific time period or until another PRACH configuration update is received. The UE can determine whether to follow the first PRACH configuration or the second PRACH configuration based on, for example, the current time or the most recent dynamic configuration message. The second PRACH configuration may include one or more of the following: multiple RACH timings in the frequency domain, a PRACH configuration index, multiple random access preambles, multiple contention-based preambles, or multiple SSBs per RACH timing. Therefore, the second PRACH configuration can be used to modify the available PRACH resources. For example, during expected busy periods, the second PRACH configuration can expand the available PRACH resources to reduce the probability of collisions, thereby reducing RACH process failures.

[0073] Figure 4 This is a schematic diagram 400 illustrating an example message exchange of a 4-step RACH procedure 404 between base station 102 and UE 104 in an access network. UE 104 may include a UE random access component 140. Base station 102 may include a BS random access component 198.

[0074] UE 104 can be configured to perform RACH procedure 404 based on PRACH configuration. For example, base station 102 can send system information 460 including the first PRACH configuration. Typically, the system information is not dynamically updated. System information 460 may be applicable to any UE attempting to connect to base station 102, including UEs in an idle state. Therefore, frequent updates to system information 460 may not be feasible.

[0075] In some implementations, system information 460 may include a second PRACH configuration. For example, system information 460 may include a second set of PRACH parameters that can be dynamically activated. For example, base station 102 may send a dynamic configuration message 464 to activate the second PRACH configuration. In other implementations, the second PRACH configuration may follow a pattern. For example, the pattern may specify a specific time of day during which the second PRACH configuration will be followed. For example, the pattern may indicate that the second PRACH configuration will be used during certain busy times of the day, such as rush hour. Busy times can be determined based on records of the performed RACH procedures.

[0076] In some implementations, base station 102 may send RRC configuration 462 that includes one or more PRACH configuration parameters. For example, base station 102 may send RRC configuration 462 to set PRACH parameters for a specific UE. RRC configuration 462 may be a higher-layer (e.g., Layer 3) message carried on PDSCH. Therefore, UE 104 may need to be in connected mode to receive RRC configuration 462.

[0077] In some implementations, base station 102 may send dynamic configuration message 464. Dynamic configuration message 464 may be referred to as a non-RRC message. Dynamic configuration message 464 may be sent as downlink control information (DCI), media access control (MAC) control element (CE), or paging message. Dynamic configuration message 464 may include a PRACH configuration update indicating one or more parameters of a second PRACH configuration.

[0078] The second PRACH configuration may include one or more of the following: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of SSBs per RACH opportunity. The number of RACH opportunities in the frequency domain defines the frequency domain resources used for PRACH. The PRACH configuration index (e.g., the prachConfIndex parameter) specifies the index that informs the UE which frame number and which subframe number within that frame includes the PRACH resources. In other words, the PRACH configuration index defines the time domain resources used for PRACH. The number of random access preambles can be the number of preambles that the UE can select from. The number of contention-based preambles can define a subset of the number of preambles used for contention-based random access. The number of SSBs per RACH opportunity can define which RACH opportunity the UE will use based on the selected SSBs.

[0079] Additionally, referring to Table 1 (below), during operation, due to the occurrence of one or more RACH trigger events 402, UE 104 may implement the NR RACH procedure 404 according to the 4-step NR RACH message flow. Suitable examples of RACH trigger events 402 may include, but are not limited to: (i) UE 104 performing initial access to transition from the RRC_IDLE state to the RRC_CONNECTEDACTIVE state; (ii) UE 104 detecting downlink (DL) data arrival while in the RRC_IDLE state or the RRC_CONNECTED INACTIVE state; (iii) UE 104 determining UL data arrival from a higher layer while in the RRC_IDLE state or the RRC_CONNECTED INACTIVE state; (iv) UE 104 performing a handover from another station to base station 102 during connected operation mode; and (v) UE performing a connection reconstruction procedure, such as a beam failure recovery procedure.

[0080] The NR RACH procedure 404 can be associated with either a contention-based random access procedure or a contention-free random access procedure. In one implementation, a contention-based NR RACH procedure corresponds to the following RACH triggering events 402: initial access from RRC_IDLE to RRC_CONNECTED ACTIVE; arrival of UL data during RRC_IDLE or RRC_CONNECTED INACTIVE; and connection reconstruction. In one implementation, a contention-free NR RACH procedure corresponds to the following RACH triggering events 402: arrival of downlink (DL) data during RRC_IDLE or RRC_CONNECTED INACTIVE; and handover during connected operation mode.

[0081] When any of the aforementioned RACH triggering events 402 occur, the execution of the NR RACH procedure 404 may include a 4-step NRRACH message flow (see [link to NRRACH procedure]). Figure 4 (as shown in Table 1), wherein UE 104 exchanges messages with one or more base stations 102 to obtain access to the wireless network and establish a communication connection. The messages may be referred to as random access messages 1 to 4, RACH messages 1 to 3, or alternatively as message-carrying PHY channels (e.g., message 3PUSCH).

[0082]

[0083] Table 1: NR RACH procedure, including messages and message content sent on the corresponding physical (PHY) channel.

[0084] In the first step of the first RACH procedure, for example, UE 104 may send a first message (Msg1) 410 to one or more base stations 102 via a physical channel (such as the Physical Random Access Channel (PRACH)), which may be referred to as a random access request message. For example, Msg1 may include one or more of a RACH preamble and resource requirements. UE 104 may send Msg1 on a random access timing (RO). In one aspect, the RACH preamble may be a relatively long preamble sequence, which is easier for base station 102 to receive than OFDM symbols. In another aspect, the UE random access component 140 may select the beam for transmission of Msg1 based on the received synchronization signal block (SSB) sent by base station 102. As described above, the second PRACH configuration may include one or more of the following: the number of RACH timings in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of SSBs per RACH timing. Therefore, UE 104 can send Msg1 410 based on the second PRACH configuration.

[0085] In the second step of the RACH procedure, base station 102 may respond to Msg1 by sending a second message (Msg2), which may be referred to as a Random Access Response (RAR) message. The RAR message may include a Physical Downlink Control Channel (PDCCH) 420 and a Physical Downlink Shared Channel (PDSCH) 430. In one aspect, UE random access component 140 may monitor the PDCCH during the first RAR window 470 based on the first Msg1 410, to detect the PDCCH 420 of the first RAR message as a DCI format 1_0 where the CRC is scrambled by the RA-RNTI corresponding to the first Msg 410, and to receive the PDSCH 430 of the RAR message as a transport block in the corresponding PDSCH within the RAR window.

[0086] UE 104 can receive a transport block in the corresponding PDSCH indicated by the successfully decoded PDCCH 420. UE 104 can decode and parse the transport block to obtain the Random Access Preamble Identifier (RAPID) associated with Msg1. For example, Msg2 may include one or more of the following: detected preamble identifier (ID), timing advance (TA) value, temporary cell radio network temporary identifier (TC-RNTI), backoff indicator, UL grant, and DL grant. If UE 104 identifies the RAPID corresponding to Msg1 410 in the transport block, UE 104 can identify the corresponding UL grant for Msg3. This is referred to as RAR UL grant in the physical layer.

[0087] In response to receiving Msg2, UE 104 sends a third message (Msg3) 440 to base station 102 via a physical uplink channel (such as PUSCH) based on the RAR UL permission provided in Msg2 of the selected serving base station 102. This message may be an RRC connection request or a scheduling request.

[0088] In response to receiving Msg3 440, base station 102 may send a fourth message (Msg4) 450 to UE 104 via PDCCH and PDSCH, which may be referred to as a contention resolution message. For example, Msg4 may include a Cell Radio Network Temporary Identifier (C-RNTI) for UE 104 to use in subsequent communications.

[0089] In some example scenarios, conflicts may occur between two or more UEs 104 requesting access. For example, two or more UEs 104 may send Msg1 with the same RACH preamble, since the number of RACH preambles can be finite and can be randomly selected by each UE 104 during a contention-based NR RACH process. Therefore, each conflicting UE 104 that selects the same RACH preamble will receive the same temporary C-RNTI and the same UL permission, and thus each UE 104 may send a similar Msg3. In this case, base station 102 can resolve the conflict in one or more ways. In a first scenario, the corresponding Msg3 from each conflicting UE 104 may interfere with other Msg3s, so base station 102 may not send Msg4. Then each UE 104 will retransmit Msg1 using a different RACH preamble. In a second scenario, base station 102 may successfully decode only one Msg3 and send an ACK message to UE 104 corresponding to the successfully decoded Msg3. In the third scenario, base station 102 can successfully decode Msg3 from each conflicting UE 104 and then send Msg4 with a contention resolution identifier (such as an identifier bound to one of the UEs) to each conflicting UE. Each conflicting UE 104 receives Msg4, decodes Msg2, and determines whether UE 104 is the correct UE by successfully matching or identifying the contention resolution identifier. This problem may not occur in a contention-free NRRACH process because in this case, base station 102 can inform UE 104 which RACH preamble to use.

[0090] In a two-step RACH process, the UE sends both the RACH preamble and the payload to the base station (e.g., the gNB) before receiving the random access response from the gNB. As an example, a two-step RACH for NR can have design objectives including that the two-step RACH should be operable regardless of whether the UE has a valid timing advance (TA). Two-step RACH is applicable to any cell size supported in Release 15 NR. In a two-step RACH, multiple messages from a four-step RACH process can be combined into a single message. More specifically, MsgA combines Msg1 and Msg3, and MsgB combines Msg2 and Msg4. MsgA may include a preamble and a PUSCH carrying the payload, where the content of MsgA includes the equivalent content of Msg3 from the four-step RACH. The content of MsgB includes the equivalent content of Msg2 and Msg4 from the four-step RACH. In one aspect, a second PRACH configuration can be dynamically selected for the two-step RACH process. For example, when the number of RACH processes is expected to increase, a second RACH configuration can be selected.

[0091] Figure 5 This is message diagram 500, which includes messages that can be sent to establish a connection between UE 104 and base station 502 or base station 504. (See above regarding...) Figure 4 The base station 502 (which may be an example of base station 102) discussed may transmit system information 460 that may include at least a first RACH configuration. UE 104 may, for example, establish an RRC connection 510 with base station 502 based on the first RACH configuration. Base station 502 may be referred to as a serving cell, pCell, or serving base station. Base station 502 may also be a pCell of a primary cell group (MCG).

[0092] As described above, UE 104 can receive RRC configuration 462 including one or more PRACH parameters. As described above, UE 104 can receive dynamic configuration message 464. Dynamic configuration message 464 may include a PRACH configuration update indicating one or more parameters of a second PRACH configuration.

[0093] At box 520, in one aspect of this disclosure, UE 104 can determine that RRC connection 510 has been lost. For example, UE 104 can detect conditions indicating that RRC connection 510 has been lost. Example conditions include: radio link failure of MCG, synchronization reconfiguration failure of MCG, NR mobility failure, integrity check failure, or RRC connection reconfiguration failure. In response to determining that RRC connection 510 has been lost, UE 104 can determine to attempt to re-establish the RRC connection with the same serving cell (e.g., base station 502) or another base station (e.g., base station 504). Additionally, although... Figure 5The diagram illustrates a connection reconstruction scenario, but the two-step RACH process can be derived from the above. Figure 4 The RACH trigger event 402 is being discussed.

[0094] In another aspect of this disclosure, serving base station 502 may send a handover command 530, and UE 104 may receive the handover command 530. The handover command 530 may instruct UE 104 to switch to base station 504, which may be referred to as the target cell or target base station. In one aspect, the handover command 530 may include a contention-free random access (CFRA) preamble that UE 104 may use to establish a connection with the target base station 504.

[0095] In one aspect, the serving base station 502 and the target base station 504 can communicate regarding handover via backhaul 532. For example, the serving base station 502 and the target base station 504 can share the CFRA preamble. The target base station 504 can reserve the CFRA preamble for UE 104.

[0096] In response to the detection of RRC connection loss at block 520 or the receipt of handover command 530, UE 104 can select a PRACH configuration at block 534. For example, UE 104 can determine that a second PRACH configuration is applicable. In some implementations, the second PRACH configuration may be applicable based on the current time being within a defined time period for the second PRACH configuration. In other implementations, the second PRACH configuration may be applicable based on the most recent dynamic configuration message 464 indicating the second PRACH configuration.

[0097] Based on the selected PRACH configuration, UE 104 may attempt to establish a connection with either base station 502 or base station 504. In the event of a handover, the target base station 504 may be indicated by a handover command 530. If an RRC connection loss is detected at block 520, UE 104 may select the strongest base station with which to re-establish a connection. In either case, UE 104 may use a RACH procedure to establish a connection. Specifically, for a two-step RACH procedure, UE 104 may send msgA PRACH 540. msgA PRACH 540 may be based on the selected PRACH configuration (e.g., a second PRACH configuration). For example, UE 104 may determine one or more of the following based on the second PRACH configuration: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of SSBs per RACH opportunity. In one aspect, if a CFRA preamble has already been provided to UE 104, msgA PRACH 540 may be a CFRA preamble. Otherwise, UE104 can select the RACH preamble based on the RACH opportunity. Target base station 504 can receive msgA PRACH 540.

[0098] As described above, the two-step RACH procedure also includes a RACH payload for msgA. Therefore, UE 104 can transmit msgA PUSCH 550 for the RACH payload. UE 104 can transmit msgA PUSCH 550 on the resources of the target base station 504 specified for RACH msgA PUSCH 550. The target base station 504 can receive RACH msgA PUSCH 550.

[0099] The target base station 504 can send msgB 560 to complete the 2-step RACH procedure. For example, base station 504 can send msgB 560 on the PDSCH.

[0100] Figure 6 This is a flowchart of a wireless communication method 600. Method 600 can be performed by a UE (e.g., UE 104 including UE Random Access Component 140 or device 702 / 702'). Optional aspects are shown in dashed lines. Method 600 can be performed by a UE (such as UE 104, which may include memory 360 and may be the entire UE 104 or components of UE 104, such as UE Random Access Component 140, TX processor 368, RX processor 356, or controller / processor 359). Method 600 can allow UE 104 to dynamically select a PRACH configuration for the RACH procedure.

[0101] At block 610, method 600 may include: determining a first PRACH configuration. In one aspect, for example, UE 104, RX processor 356, and / or controller / processor 359 may execute UE random access component 140 and / or system configuration component 142 to determine the first PRACH configuration. For example, system configuration component 142 may receive system information 460 including the first PRACH configuration. In some implementations, system configuration component 142 may receive RRC configuration 462 including one or more parameters of the first PRACH configuration. Therefore, UE 104, RX processor 356, and / or controller / processor 359 executing UE random access component 140 and / or system configuration component 142 may provide units for determining the first PRACH configuration.

[0102] At block 620, method 600 may include: determining a second PRACH configuration. In one aspect, for example, UE 104, RX processor 356, and / or controller / processor 359 may execute UE random access component 140 and / or dynamic configuration component 144 to determine the second PRACH configuration. For example, at sub-block 622, block 620 may include receiving a dynamic configuration message including a PRACH configuration update. For example, dynamic configuration component 144 may receive a dynamic configuration message 464 including a PRACH configuration update. Dynamic configuration message 464 may be one of DCI, MAC-CE, or a paging message. In some implementations, the second PRACH configuration is valid until a second PRACH configuration update is received (e.g., in another dynamic configuration message 464). In other implementations, the second PRACH configuration is valid for the time period indicated by the PRACH configuration update. For example, the PRACH configuration update may indicate the number of hours or minutes during which the second PRACH configuration is valid. In some implementations, the PRACH configuration update includes a set of PRACH configuration parameters. In other words, the dynamic configuration message 464 may carry values ​​of PRACH configuration parameters for the second PRACH configuration. In other implementations, the PRACH configuration update indicates the configured PRACH configuration. For example, the dynamic configuration message 464 may include an index identifying a pre-configured PRACH configuration. For example, the pre-configured PRACH configuration may be defined by system information 460 or defined in a standard document or regulation. As another example, at sub-block 624, block 620 may optionally include receiving system information including the second PRACH configuration. For example, the dynamic configuration component 144 may receive system information 460, which may include the second PRACH configuration. Therefore, the system information 460 may include both the first PRACH configuration and the second PRACH configuration. In some implementations, the first PRACH configuration and the second PRACH configuration follow a time pattern. Therefore, the UE 104, RX processor 356, and / or controller / processor 359 performing the UE random access component 140 and / or dynamic configuration component 144 may provide a unit for determining the second PRACH configuration.

[0103] At block 630, method 600 may include determining compliance with a second PRACH configuration based on the current time or a dynamic configuration message. In one aspect, for example, UE 104, RX processor 356, and / or controller / processor 359 may execute UE random access component 140 and / or selection component 146 to determine compliance with the second PRACH configuration based on the current time or a dynamic configuration message. For example, if the first PRACH configuration and the second PRACH configuration follow a time pattern, selection component 146 may determine which PRACH configuration corresponds to the current time. The current time may be network time. UE 104 may, for example, be synchronized with the network based on SSB. Similarly, if dynamic configuration message 464 defines an applicable time period for the second PRACH configuration, selection component 146 may determine whether the current time is within the applicable time period. As another example, if dynamic configuration message 464 indicates that the second PRACH configuration is applicable until another configuration is received, selection component 146 may determine that the second PRACH configuration is applicable based on the most recent dynamic configuration message 464. Therefore, the UE 104, RX processor 356, and / or controller / processor 359 that perform the UE random access component 140 and / or selection component 146 can provide a unit for determining whether to follow the second PRACH configuration based on the current time or dynamic configuration message.

[0104] At block 640, method 600 may include sending a first message for the RACH procedure based on a second PRACH configuration. In one aspect, for example, UE 104, TX processor 368, and / or controller / processor 359 may execute UE random access component 140 and / or preamble component 148 to send the first message for the RACH procedure based on the second PRACH configuration. For example, preamble component 148 may send Msg1 410 or MsgA PRACH 540 based on the second PRACH configuration. Therefore, UE 104, TX processor 368, and / or controller / processor 359 executing UE random access component 140 and / or preamble component 148 may provide elements for sending the first message for the RACH procedure based on the second PRACH configuration.

[0105] Figure 7 This is a conceptual data flow diagram 700 illustrating the data flow between different units / components in example device 702. Device 702 may be a UE. Device 702 may include a UE random access component 140. Device 702 may include a receiving component 704 that receives downlink signals from base station 750, such as system information 460 and / or dynamic configuration messages 464. The receiving component 704 may provide system information 460 to system configuration component 142 and dynamic configuration messages 464 to dynamic configuration component 144.

[0106] System configuration component 142 can receive system information 460 from receiving component 704. System configuration component 142 can determine a first PRACH configuration based on system information 460. In some implementations, system configuration component 142 can also receive RRC messages and determine or update the first PRACH configuration based on RRC messages. System configuration component 142 can provide the first PRACH configuration to selection component 146.

[0107] Dynamic configuration component 144 can receive dynamic configuration message 464 from receiving component 704. Dynamic configuration component 144 can determine a second PRACH configuration based on dynamic configuration message 464. For example, dynamic configuration message 464 may include parameters of the second PRACH configuration. In another example, dynamic configuration message 464 may include an index of the second PRACH configuration. Dynamic configuration component 144 can provide the second PRACH configuration to selection component 146.

[0108] Selection component 146 may receive a first PRACH configuration from system configuration component 142 and a second PRACH configuration from dynamic configuration component 144. Selection component 146 may select between the first and second PRACH configurations based on the current time or a dynamic configuration message. For example, selection component 146 may compare the current time with the applicable time period defined by the second PRACH configuration to determine whether to follow the second PRACH configuration. As another example, when dynamic configuration message 464 indicates that the second PRACH configuration is applicable until a subsequent PRACH configuration is received, selection component 146 may determine that the second PRACH configuration will be followed. Selection component 146 may provide the selected PRACH configuration to preamble component 148.

[0109] The preamble component 148 may receive the selected PRACH configuration from the selection component 146. The preamble component 148 may transmit the first message of the RACH procedure based on the second PRACH configuration. For example, the preamble component 148 may select a preamble for Msg1 or MsgA based on the indicated number of random access preambles or based on the number of contention preambles. The preamble component 148 may also select a resource (e.g., a RACH timing) based on the number of RACH timings in the frequency domain, the PRACH configuration index, and / or the number of SSBs per RACH timing. The preamble component 148 may transmit the first message of the RACH procedure with the selected preamble on the selected resource via the transmission component 710.

[0110] The device may include execution Figure 6 The above process is an additional component of each box in the algorithm's box. Accordingly, the above... Figure 6Each box in the flowchart can be executed by a component, and the apparatus can include one or more of these components. A component can be one or more hardware components specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for processor implementation, or some combination thereof.

[0111] Figure 8 This is a flowchart of an example method 800 for receiving the first message of the RACH procedure based on dynamic PRACH configuration. Method 800 can be performed by a base station (e.g., base station 102, which may include memory 376, and may be the entire base station 102 or components of base station 102, such as BS random access component 198, TX processor 316, RX processor 370, or controller / processor 375). Method 800 can be performed by BS random access component 198 communicating with UE random access component 140 of UE 104.

[0112] At block 810, method 800 may include transmitting system information indicating a first PRACH configuration. In one aspect, for example, controller / processor 375 and / or TX processor 316 may execute BS random access component 198 and / or system information component 906 to transmit system information indicating a first PRACH configuration. Therefore, base station 102, controller / processor 375, and / or TX processor 316 executing BS random access component 198 and / or system information component 906 may provide units for transmitting system information indicating a first PRACH configuration.

[0113] At block 820, method 800 may include determining whether a second PRACH configuration is applicable based on the current time. In one aspect, for example, controller / processor 375 and / or TX processor 316 may execute BS random access component 198 and / or selection component 908 to determine whether a second PRACH configuration is applicable based on the current time. Therefore, base station 102, controller / processor 375, and / or TX processor 316 executing BS random access component 198 and / or selection component 908 may provide elements for determining whether a second PRACH configuration is applicable based on the current time.

[0114] At block 830, method 800 may include sending a dynamic configuration message including a PRACH configuration update in response to determining a second PRACH configuration. In one aspect, for example, controller / processor 375 and / or TX processor 316 may execute BS random access component 198 and / or dynamic messaging component 914 to send a dynamic configuration message 464 including a PRACH configuration update in response to determining a second PRACH configuration. For example, dynamic configuration message 464 may be one of DCI, MAC-CE, or paging messages. In some implementations, the second PRACH configuration is valid until the second PRACH configuration update is sent. In other implementations, the second PRACH configuration is valid for the time period indicated by the PRACH configuration update. In some implementations, the PRACH configuration update includes a set of PRACH configuration parameters. In other implementations, the PRACH configuration update indicates the configured PRACH configuration. Therefore, the base station 102, controller / processor 375, and / or TX processor 316 that execute the BS random access component 198 and / or dynamic message transmission component 914 can provide a unit for sending a dynamic configuration message including a PRACH configuration update in response to determining a second PRACH configuration.

[0115] At block 840, method 800 may include receiving a first message of the RACH procedure based on a second PRACH configuration. In one aspect, for example, controller / processor 375 and / or TX processor 316 may execute BS random access component 198 and / or preamble receiver component 912 to receive the first message of the RACH procedure based on the second PRACH configuration. Therefore, base station 102 executing BS random access component 198 and / or preamble receiver component 912, controller / processor 375 and / or TX processor 316 may provide elements for receiving the first message of the RACH procedure based on the second PRACH configuration.

[0116] Figure 9 This is a conceptual data flow diagram 900 illustrating the data flow between different units / components in example device 902. Device 902 may be a base station. Device 902 may include a BS random access component 198. Device 902 may include a receiving component 904 that receives uplink signals from UE 950 including a first message (e.g., a preamble) of the RACH procedure.

[0117] Apparatus 902 may include a system information component 906 that transmits system information indicating at least a first PRACH configuration. The first PRACH configuration may be configured by a network operator. System information component 906 may generate a system information block (SIB) including parameters of the first PRACH configuration. In some implementations, system information component 906 may additionally transmit a second PRACH configuration. For example, system information component 906 may generate an additional SIB including parameters of the second PRACH configuration. The second PRACH configuration may be configured by a network operator. In some implementations, the second PRACH configuration is configured with a time period to which the second PRACH configuration is applicable. System information component 906 may periodically transmit the SIB via transmitting component 910.

[0118] Apparatus 902 may include a selection component 908. Selection component 908 may select between a first PRACH configuration and a second PRACH configuration. For example, selection component 908 may determine that the second PRACH configuration is applicable based on the current time. For example, selection component 908 may determine that the current time corresponds to a time period during which the second PRACH configuration is applicable. Selection component 908 may provide an indication of the selected PRACH configuration to preamble receiver component 912. In some implementations, selection component 908 may provide the second PRACH configuration or an indication thereof to dynamic message delivery component 914.

[0119] The dynamic messaging component 914 can receive a second PRACH configuration from the selection component 908. The dynamic messaging component 914 can generate a dynamic configuration message 464 based on the second PRACH configuration. The dynamic messaging component 914 can send the dynamic configuration message 464 via the sending component 910.

[0120] The preamble receiver component 912 can receive the first message of the RACH procedure based on the selected PRACH configuration. The first message can be, for example, Msg1 410 or MsgA 540. The preamble receiver component 912 can monitor resources based on the selected PRACH configuration. The preamble receiver component 912 can determine whether the received signal includes one or more preambles from the preambles indicated by the selected PRACH configuration.

[0121] Device 902 may include execution Figure 9 The additional components of each box in the algorithm's flowchart above. Accordingly, Figure 9Each block in the aforementioned flowchart can be executed by a component, and the apparatus can include one or more of these components. A component can be one or more hardware components specifically configured to execute the process / algorithm, implemented by a processor configured to execute the process / algorithm, stored in a computer-readable medium for processor implementation, or some combination thereof.

[0122] Some other example terms

[0123] Implementation examples are described in the following numbered clauses:

[0124] 1. A method for wireless communication, comprising:

[0125] Determine the configuration of the first physical random access channel (PRACH);

[0126] Determine the second PRACH configuration;

[0127] Determine whether to follow the second PRACH configuration based on the current time or dynamic configuration message; and

[0128] The first message of the random access (RACH) procedure is sent based on the second PRACH configuration.

[0129] 2. The method according to Clause 1, wherein determining the second PRACH configuration includes: receiving the dynamic configuration message including a PRACH configuration update.

[0130] 3. The method according to Clause 2, wherein the dynamic configuration message is one of downlink control information (DCI), media access control (MAC) control element (CE), or paging message.

[0131] 4. The method according to Clause 3, wherein the second PRACH configuration is valid until a second PRACH configuration update is received.

[0132] 5. The method according to Clause 3, wherein the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0133] 6. The method according to any one of Clauses 2-5, wherein the PRACH configuration update includes a set of PRACH configuration parameters.

[0134] 7. The method according to any one of clauses 2-5, wherein the PRACH configuration update indicates the configured PRACH configuration.

[0135] 8. The method according to any one of Clauses 1-3, wherein the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0136] 9. The method according to any one of clauses 1-8, wherein the first PRACH configuration is based on a system information block.

[0137] 10. The method according to any one of Clauses 1-9, wherein the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0138] 11. The method according to any one of clauses 1-10, wherein the second PRACH configuration is used for a 4-step RACH process or a 2-step RACH process.

[0139] 12. A method for wireless communication, comprising:

[0140] Send system information indicating the configuration of the first physical random access channel (PRACH);

[0141] Determining whether a second PRACH configuration is applicable based on the current time; and

[0142] The first message of the random access (RACH) procedure is received based on the second PRACH configuration.

[0143] 13. The method according to Clause 12 further includes: sending a dynamic configuration message including a PRACH configuration update in response to determining the second PRACH configuration.

[0144] 14. The method according to Clause 13, wherein the dynamic configuration message is one of downlink control information (DCI), media access control (MAC) control element (CE), or paging message.

[0145] 15. The method according to Clause 14, wherein the second PRACH configuration is valid until a second PRACH configuration update is sent.

[0146] 16. The method according to Clause 14, wherein the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0147] 17. The method according to any one of clauses 13-16, wherein the PRACH configuration update includes a set of PRACH configuration parameters.

[0148] 18. The method according to any one of clauses 13-16, wherein the PRACH configuration update indicates the configured PRACH configuration.

[0149] 19. The method according to any one of clauses 12-14, wherein the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0150] 20. The method according to any one of Clauses 12-19, wherein the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0151] 21. The method according to any one of clauses 12-20, wherein the second PRACH configuration is used for a 4-step RACH process or a 2-step RACH process.

[0152] 22. An apparatus for wireless communication, comprising:

[0153] Memory that stores computer-executable instructions; and

[0154] At least one processor, coupled to the memory and configured to execute the computer-executable instructions to perform the following operations:

[0155] Determine the configuration of the first physical random access channel (PRACH);

[0156] Determine the second PRACH configuration;

[0157] Determine whether to follow the second PRACH configuration based on the current time or dynamic configuration message; and

[0158] The first message of the random access (RACH) procedure is sent based on the second PRACH configuration.

[0159] 23. The apparatus according to clause 22, wherein the at least one processor is configured to: receive the dynamic configuration message including a PRACH configuration update.

[0160] 24. The apparatus according to Clause 23, wherein the dynamic configuration message is one of downlink control information (DCI), media access control (MAC) control element (CE), or paging message.

[0161] 25. The apparatus according to Clause 24, wherein the second PRACH configuration is valid until a second PRACH configuration update is received.

[0162] 26. The apparatus according to Clause 24, wherein the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0163] 27. The apparatus according to any one of clauses 23-26, wherein the PRACH configuration update includes a set of PRACH configuration parameters.

[0164] 28. The apparatus according to any one of clauses 23-26, wherein the PRACH configuration update indicates the configured PRACH configuration.

[0165] 29. The apparatus according to any one of clauses 22-24, wherein the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0166] 30. The apparatus according to any one of clauses 22-29, wherein the first PRACH configuration is based on a system information block.

[0167] 31. The apparatus according to any one of clauses 22-30, wherein the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0168] 32. The apparatus according to any one of clauses 22-31, wherein the second PRACH is configured for a 4-step RACH process or a 2-step RACH process.

[0169] 33. An apparatus for wireless communication, comprising:

[0170] Memory that stores computer-executable instructions; and

[0171] At least one processor, coupled to the memory and configured to execute the computer-executable instructions to perform the following operations:

[0172] Send system information indicating the configuration of the first physical random access channel (PRACH);

[0173] Determining whether a second PRACH configuration is applicable based on the current time; and

[0174] The first message of the random access (RACH) procedure is received based on the second PRACH configuration.

[0175] 34. The apparatus according to clause 33, wherein the at least one processor is configured to: send a dynamic configuration message including a PRACH configuration update in response to determining the second PRACH configuration.

[0176] 35. The apparatus according to Clause 34, wherein the dynamic configuration message is one of downlink control information (DCI), media access control (MAC) control element (CE), or paging message.

[0177] 36. The apparatus according to Clause 35, wherein the second PRACH configuration is valid until a second PRACH configuration update is sent.

[0178] 37. The apparatus according to Clause 35, wherein the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0179] 38. The apparatus according to any one of clauses 34-37, wherein the PRACH configuration update includes a set of PRACH configuration parameters.

[0180] 39. The apparatus according to any one of clauses 34-37, wherein the PRACH configuration update indicates the configured PRACH configuration.

[0181] 40. The apparatus according to any one of clauses 33-35, wherein the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0182] 41. The apparatus according to any one of clauses 33-40, wherein the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0183] 42. The apparatus according to any one of clauses 33-41, wherein the second PRACH is configured for a 4-step RACH process or a 2-step RACH process.

[0184] 43. An apparatus for wireless communication, comprising:

[0185] A unit used to determine the configuration of the first physical random access channel (PRACH);

[0186] Unit used to determine the second PRACH configuration;

[0187] Used to determine the unit that conforms to the second PRACH configuration based on the current time or dynamic configuration messages; and

[0188] A unit for sending the first message of the random access (RACH) procedure based on the second PRACH configuration.

[0189] 44. The apparatus according to clause 43, wherein the unit for determining the second PRACH configuration is configured to: receive the dynamic configuration message including a PRACH configuration update.

[0190] 45. The apparatus according to Clause 44, wherein the dynamic configuration message is one of downlink control information (DCI), media access control (MAC) control element (CE), or paging message.

[0191] 46. ​​The apparatus according to Clause 45, wherein the second PRACH configuration is valid until a second PRACH configuration update is received.

[0192] 47. The apparatus according to Clause 45, wherein the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0193] 48. The apparatus according to any one of clauses 44-47, wherein the PRACH configuration update includes a set of PRACH configuration parameters.

[0194] 49. The apparatus according to any one of clauses 44-47, wherein the PRACH configuration update indicates the configured PRACH configuration.

[0195] 50. The apparatus according to any one of clauses 43-45, wherein the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0196] 51. The apparatus according to any one of clauses 43-50, wherein the first PRACH configuration is based on a system information block.

[0197] 52. The apparatus according to any one of clauses 43-51, wherein the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0198] 53. The apparatus according to any one of clauses 43-52, wherein the second PRACH is configured for a 4-step RACH process or a 2-step RACH process.

[0199] 54. An apparatus for wireless communication, comprising:

[0200] A unit for transmitting system information indicating the configuration of the first physical random access channel (PRACH);

[0201] Units used to determine whether a second PRACH configuration is applicable based on the current time; and

[0202] A unit for receiving the first message of the random access (RACH) procedure based on the second PRACH configuration.

[0203] 55. The apparatus according to Clause 54 further includes: a unit for sending a dynamic configuration message including a PRACH configuration update in response to determining the second PRACH configuration.

[0204] 56. The apparatus according to Clause 55, wherein the dynamic configuration message is one of downlink control information (DCI), media access control (MAC) control element (CE), or paging message.

[0205] 57. The apparatus according to Clause 56, wherein the second PRACH configuration is valid until a second PRACH configuration update is sent.

[0206] 58. The apparatus according to Clause 56, wherein the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0207] 59. The apparatus according to any one of clauses 55-58, wherein the PRACH configuration update includes a set of PRACH configuration parameters.

[0208] 60. The apparatus according to any one of clauses 55-58, wherein the PRACH configuration update indicates the configured PRACH configuration.

[0209] 61. The apparatus according to any one of clauses 54-56, wherein the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0210] 62. The apparatus according to any one of clauses 54-61, wherein the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, the PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0211] 63. The apparatus according to any one of clauses 54-62, wherein the second PRACH is configured for a 4-step RACH process or a 2-step RACH process.

[0212] 64. A non-transitory computer-readable medium storing computer-executable code, said code, when executed by a processor, causing the processor to perform the following operations:

[0213] Determine the configuration of the first physical random access channel (PRACH);

[0214] Determine the second PRACH configuration;

[0215] Determine whether to follow the second PRACH configuration based on the current time or dynamic configuration message; and

[0216] The first message of the random access (RACH) procedure is sent based on the second PRACH configuration.

[0217] 65. The non-transitory computer-readable medium according to Clause 64, wherein the code for determining the second PRACH configuration includes: code for receiving the dynamic configuration message including a PRACH configuration update.

[0218] 66. The non-transitory computer-readable medium as described in Clause 65, wherein the dynamic configuration message is one of downlink control information (DCI), media access control (MAC) control element (CE), or paging message.

[0219] 67. A non-transitory computer-readable medium as described in Clause 66, wherein the second PRACH configuration is valid until a second PRACH configuration update is received.

[0220] 68. The non-transitory computer-readable medium as described in Clause 66, wherein the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0221] 69. A non-transitory computer-readable medium according to any one of clauses 65-68, wherein the PRACH configuration update includes a set of PRACH configuration parameters.

[0222] 70. A non-transitory computer-readable medium according to any one of clauses 65-68, wherein the PRACH configuration update indicates the configured PRACH configuration.

[0223] 71. A non-transitory computer-readable medium according to any one of clauses 64-66, wherein the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0224] 72. A non-transitory computer-readable medium according to any one of clauses 64-71, wherein the first PRACH configuration is based on a system information block.

[0225] 73. A non-transitory computer-readable medium according to any one of clauses 64-72, wherein the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, a PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0226] 74. A non-transitory computer-readable medium according to any one of clauses 64-73, wherein the second PRACH configuration is used for a 4-step RACH process or a 2-step RACH process.

[0227] 75. A non-transitory computer-readable medium storing computer-executable code, said code, when executed by a processor, causing the processor to perform the following operations:

[0228] Send system information indicating the configuration of the first physical random access channel (PRACH);

[0229] Determining whether a second PRACH configuration is applicable based on the current time; and

[0230] The first message of the random access (RACH) procedure is received based on the second PRACH configuration.

[0231] 76. The non-transitory computer-readable medium as described in Clause 75 further includes: code for sending a dynamic configuration message including a PRACH configuration update in response to determining the second PRACH configuration.

[0232] 77. The non-transitory computer-readable medium as described in Clause 76, wherein the dynamic configuration message is one of downlink control information (DCI), media access control (MAC) control element (CE), or paging message.

[0233] 78. A non-transitory computer-readable medium as described in Clause 77, wherein the second PRACH configuration is valid until a second PRACH configuration update is sent.

[0234] 79. The non-transitory computer-readable medium as described in Clause 77, wherein the second PRACH configuration is valid during the time period indicated by the PRACH configuration update.

[0235] 80. A non-transitory computer-readable medium according to any one of clauses 76-79, wherein the PRACH configuration update includes a set of PRACH configuration parameters.

[0236] 81. A non-transitory computer-readable medium according to any one of clauses 76-79, wherein the PRACH configuration update indicates the configured PRACH configuration.

[0237] 82. A non-transitory computer-readable medium according to any one of clauses 75-78, wherein the first PRACH configuration and the second PRACH configuration follow a time pattern.

[0238] 83. A non-transitory computer-readable medium according to any one of clauses 75-82, wherein the second PRACH configuration includes one or more of the following: the number of RACH opportunities in the frequency domain, a PRACH configuration index, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH opportunity.

[0239] 84. A non-transitory computer-readable medium according to any one of clauses 75-83, wherein the second PRACH configuration is used for a 4-step RACH process or a 2-step RACH process.

[0240] It is to be understood that the specific order or hierarchy of the boxes in the disclosed process / flowchart is illustrative of the example method. It is to be understood that the specific order or hierarchy of the boxes in the process / flowchart may be rearranged based on design preferences. Furthermore, some boxes may be combined or omitted. The appended method claims give the elements of the boxes in the example order, but are not intended to limit one to the specific order or hierarchy given.

[0241] The foregoing description is provided to enable any person skilled in the art to implement the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are given the full scope consistent with the text claims, wherein reference to the singular form of an element is not intended to mean "one and only one," but rather "one or more," unless expressly stated otherwise. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred over or superior to other aspects. Unless expressly stated otherwise, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" include any combination of A, B, and / or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B, and C", "one or more of A, B, and C", and "A, B, C, or any combination thereof" can be A only, B only, C only, A and B, A and C, B and C, or A and B and C, wherein any such combination may contain one or more members of A, B, or C. All structural and functional equivalents of the elements described throughout the various aspects of this disclosure are expressly incorporated herein by reference and intended to be included by the claims, and such structural and functional equivalents are known to or will be known later to those skilled in the art. Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is expressly stated in the claims. The terms "module", "mechanism", "element", "device", etc., may not be a substitute for the term "unit". Accordingly, no claim element is to be interpreted as a functional module unless the element is expressly stated using the phrase "unit for...".

Claims

1. A method for wireless communication, comprising: The user equipment (UE) receives a dynamic configuration message that includes a Physical Random Access Channel (PRACH) configuration update, wherein the PRACH configuration update includes a PRACH configuration index for dynamic PRACH configuration, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH timing, wherein the dynamic configuration message is one of downlink control information (DCI) or paging message. When the dynamic configuration message indicates that the dynamic PRACH configuration is applicable, the dynamic PRACH configuration is selected, wherein the dynamic PRACH configuration is applicable until a second PRACH configuration update is received; and The first message of the Random Access (RACH) procedure is sent based on the dynamic PRACH configuration.

2. The method according to claim 1, wherein, The PRACH configuration update includes a set of PRACH configuration parameters.

3. The method according to claim 1, wherein, The PRACH configuration update indicates the configured PRACH configuration.

4. The method according to claim 1, further comprising: Receive a system information block including a first PRACH configuration, wherein the first PRACH configuration and the dynamic PRACH configuration follow a time pattern.

5. The method according to claim 1, wherein, The dynamic PRACH configuration is used for either a 4-step RACH process or a 2-step RACH process.

6. A method for wireless communication, comprising: If, based on the current time, the dynamic PRACH configuration is applicable within a defined time period for the dynamic physical random access channel (PRACH) configuration, a dynamic configuration message including a PRACH configuration update is sent. This PRACH configuration update includes the PRACH configuration index for the dynamic PRACH configuration, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH timing. The dynamic configuration message is either a downlink control information (DCI) message or a paging message. The dynamic PRACH configuration is applicable to the user equipment (UE) until a second PRACH configuration update is received at the UE. The first message of the RACH procedure is received based on the dynamic PRACH configuration.

7. The method according to claim 6, wherein, The PRACH configuration update includes a set of PRACH configuration parameters.

8. The method according to claim 6, wherein, The PRACH configuration update indicates the configured PRACH configuration.

9. The method according to claim 6, further comprising: A system information block including a first PRACH configuration is sent, wherein the first PRACH configuration and the dynamic PRACH configuration follow a time pattern.

10. The method according to claim 6, wherein, The dynamic PRACH configuration is used for either a 4-step RACH process or a 2-step RACH process.

11. An apparatus for wireless communication, comprising: Memory, which stores executable instructions for a computer; as well as At least one processor, coupled to the memory and configured to execute the computer-executable instructions to perform the following operations: The user equipment (UE) receives a dynamic configuration message that includes a Physical Random Access Channel (PRACH) configuration update, wherein the PRACH configuration update includes a PRACH configuration index for dynamic PRACH configuration, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH timing, wherein the dynamic configuration message is one of downlink control information (DCI) or paging message. When the dynamic configuration message indicates that the dynamic PRACH configuration is applicable, the dynamic PRACH configuration is selected, wherein the dynamic PRACH configuration is applicable until a second PRACH configuration update is received; and The first message of the Random Access (RACH) procedure is sent based on the dynamic PRACH configuration.

12. The apparatus according to claim 11, wherein, The PRACH configuration update includes a set of PRACH configuration parameters.

13. The apparatus according to claim 11, wherein, The PRACH configuration update indicates the configured PRACH configuration.

14. The apparatus according to claim 11, wherein, The at least one processor is further configured to execute the computer-executable instructions to receive a system information block including a first PRACH configuration, wherein the first PRACH configuration and the dynamic PRACH configuration follow a time pattern.

15. The apparatus according to claim 11, wherein, The dynamic PRACH configuration is used for either a 4-step RACH process or a 2-step RACH process.

16. An apparatus for wireless communication, comprising: Memory, which stores executable instructions for a computer; as well as At least one processor, coupled to the memory and configured to execute the computer-executable instructions to perform the following operations: If, based on the current time, the dynamic PRACH configuration is applicable within a defined time period for the dynamic physical random access channel (PRACH) configuration, a dynamic configuration message including a PRACH configuration update is sent. This PRACH configuration update includes the PRACH configuration index for the dynamic PRACH configuration, the number of random access preambles, the number of contention-based preambles, or the number of synchronization signal blocks (SSBs) per RACH timing. The dynamic configuration message is either a downlink control information (DCI) message or a paging message. The dynamic PRACH configuration is applicable to the user equipment (UE) until a second PRACH configuration update is received at the UE. The first message of the RACH procedure is received based on the dynamic PRACH configuration.

17. The apparatus according to claim 16, wherein, The PRACH configuration update includes a set of PRACH configuration parameters.

18. The apparatus according to claim 16, wherein, The PRACH configuration update indicates the configured PRACH configuration.

19. The apparatus according to claim 16, wherein, The at least one processor is further configured to execute the computer-executable instructions to send a system information block including a first PRACH configuration, wherein the first PRACH configuration and the dynamic PRACH configuration follow a time pattern.

20. The apparatus according to claim 16, wherein, The dynamic PRACH configuration is used for either a 4-step RACH process or a 2-step RACH process.

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