Two-step RACH procedure for NR reduced-capability UEs

Abstract

Random access configuration information with multiple random access configurations, which can be utilized by a UE to provide coverage enhancement for a two-step RACH procedure. The device receives the random access configuration information from the base station. The random access configuration information includes multiple random access configurations. The device selects one random access configuration from the multiple random access configurations. The device generates a first random access message with a preamble and a payload based on the selected random access configuration. The device transmits the first random access message to the base station to initiate a random access procedure.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 881,278, filed Jul. 31, 2019, entitled "Two - Step RACH Procedure for NR - Light", and U.S. Patent Application No. 16 / 913,982, filed Jun. 26, 2020, entitled "Two - Step RACH Procedure for NR Reduced Capability UE", which are hereby incorporated by reference in their entireties. Background Technical Field

[0004] This disclosure generally relates to communication systems, and more particularly, to random access procedures in wireless communication networks.

[0005] Introduction

[0006] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system may employ a multiple access technology 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.

[0007] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the urban, national, regional, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., related to the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine - type communication (mMTC), and ultra - reliable low - latency communication (URLLC). Some aspects of 5G NR may be based on the 4G Long - Term Evolution (LTE) standard. There is a need for further improvement in 5G NR technology. These improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies.

[0008] Summary

[0009] A brief overview of one or more aspects is given below to provide a basic understanding of such aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or critical elements of all aspects nor to delineate 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 description that follows.

[0010] A random access or random access channel (RACH) procedure may be performed between a user equipment (UE) and a base station so that the UE can connect to or initialize with the base station. The UE may perform the RACH procedure with the base station under many different conditions, such as initial access to a cell provided by the base station, during a handover sequence from one cell to another cell, or re-initialization with the base station to re-synchronize with the base station.

[0011] The RACH procedure may include message exchanges between the UE and the base station. For example, one type of RACH procedure may include the exchange of four messages between the UE and the base station and may be referred to as a "four-step RACH procedure". Another type of RACH procedure may include the exchange of two messages between the UE and the base station and may be referred to as a "two-step RACH procedure".

[0012] In the two-step RACH procedure, the UE may send an uplink random access message in the form of a preamble part and a payload part to the base station to initiate the two-step RACH procedure. The base station processes the message from the UE and, based on the processing result of the message from the UE, the base station may transmit a response or a downlink message to the UE. Some UEs that support the two-step RACH procedure may be considered high-end devices that can utilize high bandwidth. In some instances, the preamble part and the payload part may be transmitted by the UE to the base station using different transmission configurations and / or transmit beams. These high-end UEs may be configured to receive the response or downlink message transmitted by the base station, and the response or downlink message may cause the UE to perform additional or multiple processing steps to receive and / or process the downlink message. This may result in increased implementation complexity and / or increased signaling overhead. Some UEs that support the two-step RACH procedure may be considered low-end devices that can utilize a lower bandwidth compared to high-end UEs. These low-end devices cannot be configured to support the two-step RACH procedure utilized by high-end devices due to, for example, transmit power limitations or hardware limitations. In addition, low-end devices are likely to have limited coverage during the two-step RACH procedure. The aspects presented herein provide a solution to the coverage limitation problem of low-end UEs during the two-step RACH procedure by improving the way of configuring the two-step RACH procedure for low-end UEs. In certain aspects, the configuration of the RACH procedure may be optimized by incorporating additional parameters configured for low-end UEs.

[0013] In one aspect of the present disclosure, a method, a computer-readable medium, and a device are provided. The device may be a device at a UE. The device may be a processor and / or a modem at the UE or the UE itself. The device receives random access configuration information from a base station. The random access configuration information includes a plurality of different random access configuration sets. The device selects one random access configuration set from the different random access configuration sets. The device generates a first random access message having a preamble and a payload based on the selected different random access configuration set. The device transmits the first random access message to the base station to initiate a random access procedure.

[0014] In one aspect of the present disclosure, a method, a computer-readable medium, and a device are provided. The device may be a device at a base station. The device may be a processor and / or a modem at the base station or the base station itself. The device may transmit random access configuration information for a random access procedure to a UE, where the random access configuration information includes a plurality of random access configurations. The device may receive a first random access message from the UE to initiate a random access procedure, the first random access message including a preamble and a payload, where the configuration of the preamble and the payload is based on one random access configuration among the plurality of random access configurations. The device may process the first random access message. The device may generate a second random access message in response to the first random access message. The device transmits the second random access message to the UE.

[0015] To achieve the foregoing and related purposes, one or more aspects include the features that are fully described hereinafter and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative features of one or more aspects. However, these features are merely indicative of the various ways in which the principles of the various aspects may be employed, and this description is intended to cover all such aspects and their equivalents. Brief Description of the Drawings

[0017] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0018] Figure 2A 、 2B 、2C, and 2D are diagrams respectively illustrating examples of a first 5G NR frame, DL channels within a 5G NR subframe, a second 5G NR frame, and UL channels within a 5G NR subframe.

[0019] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0020] Figure 4 is an example communication flow for a two-step random access procedure.

[0021] Figure 5 FIG. is an illustration showing an example of a msgA channel structure according to certain aspects of the present disclosure.

[0022] Figure 6 FIG. is an illustration showing an example of resource mapping according to certain aspects of the present disclosure.

[0023] Figure 7 FIG. is a call flow diagram showing an example of a two-step RACH procedure according to certain aspects of the present disclosure.

[0024] Figure 8 FIG. is a flowchart of a wireless communication method.

[0025] Figure 9 FIG. is an illustration showing an example of a hardware implementation of an example apparatus.

[0026] Figure 10 FIG. is a flowchart of a wireless communication method.

[0027] Figure 11 FIG. is an illustration showing an example of a hardware implementation of an example apparatus.

[0028] DETAILED DESCRIPTION

[0029] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0030] Certain aspects of a telecommunications system will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in detail below and illustrated in the drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0031] By way of example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" that includes 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, systems 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 throughout this disclosure. One or more processors in the processing system can execute software. Software should be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., regardless of whether it is referred to in terms of software, firmware, middleware, microcode, hardware description language, or other terms.

[0032] Accordingly, in one or more example embodiments, the described functions can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example and not limitation, such computer-readable media can 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 the foregoing types of computer-readable media, or any other media that can be used to store instructions or data structures in the form of computer-executable code that can be accessed by a computer.

[0033] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes base stations 102, UEs 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base stations 102 can 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.

[0034] The base stations 102 configured for 4G LTE (collectively referred to as the evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a first backhaul link 132 (e.g., S1 interface). The base stations 102 configured for 5G NR (collectively referred to as the Next Generation RAN (NG-RAN)) can interface with the core network 190 via a second backhaul link 184. In addition to other functions, the base stations 102 can also perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, 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), subscriber and equipment tracking, radio access network information management (RIM), paging, positioning, and delivery of alert messages. The base stations 102 can communicate with each other directly or indirectly (e.g., via the EPC 160 or the core network 190) on a third backhaul link 134 (e.g., X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 can be wired or wireless.

[0035] Base station 102 can communicate wirelessly with UE 104. Each base station 102 can provide communication coverage for a corresponding geographic coverage area 110. There may be overlapping geographic coverage areas 110. 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 a home evolved Node B (eNB) (HeNB) that can serve a restricted group known as a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 can include an uplink (UL) (also known as the reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also known as the forward link) transmission from base station 102 to UE 104. The communication link 120 can use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. These communication links can pass through one or more carriers. For each carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) for transmission in each direction, base station 102 / UE 104 can use a spectrum with a bandwidth of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.). These carriers may or may not be adjacent to each other. The allocation of carriers can be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated to DL compared to UL). The component carriers can include a primary component carrier and one or more secondary component carriers. The primary component carrier can be referred to as the primary cell (PCell), while the secondary component carriers can be referred to as secondary cells (SCells).

[0036] Some UEs 104 can communicate with each other using device-to-device (D2D) communication links 158. The D2D communication links 158 can use DL / UL WWAN spectrum. The D2D communication links 158 can use one or more sidelink channels, such as the physical sidelink broadcast channel (PSBCH), the physical sidelink discovery channel (PSDCH), the physical sidelink shared channel (PSSCH), and the physical sidelink control channel (PSCCH). D2D communication can be through various wireless D2D communication systems, such as, by way of example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, LTE, or NR.

[0037] The wireless communication system may further 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 clear channel assessment (CCA) before communication to determine whether the channel is available.

[0038] The small cell 102' may operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' may adopt NR and use the same 5 GHz unlicensed spectrum as that used by the Wi-Fi AP 150. The small cell 102' adopting NR in the unlicensed spectrum may boost the coverage of the access network and / or increase the capacity of the access network.

[0039] Whether it is the small cell 102' or a large cell (e.g., a macro base station), the base station 102 may include and / or be referred to as an eNB, a g Node B (gNB), or another type of base station. Some base stations (such as the gNB 180) may operate in the traditional sub-6 GHz spectrum, millimeter wave (mmW) frequencies, and / or near mmW frequencies to communicate with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. The extremely high frequency (EHF) is a part of the RF in the electromagnetic spectrum. The EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. The radio waves in this frequency band may be referred to as millimeter waves. The near mmW may extend down to 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, which is also referred to as centimeter waves. The frequency range bands include frequency range 1 (FR1) (which includes the frequency band below 7.225 GHz) and frequency range 2 (FR2) (which includes the frequency band above 24.250 GHz). Communication using the mmW / near mmW radio frequency (RF) band (e.g., 3 GHz–300 GHz) has extremely high path loss and short range. The base station / UE may operate within one or more frequency range bands. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range. The base station 180 and the UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays to facilitate beamforming.

[0040] Base station 180 may transmit a beamformed signal to UE 104 in one or more transmission directions 182'. UE 104 may receive the beamformed signal from base station 180 in one or more reception directions 182". UE 104 may also transmit a beamformed signal to base station 180 in one or more transmission directions. Base station 180 may receive the beamformed signal from UE 104 in one or more reception directions. Base station 180 / UE 104 may perform beam training to determine the optimal reception and transmission directions for each of base station 180 / UE 104. The transmission and reception directions of base station 180 may be the same or may be different. The transmission and reception directions of UE 104 may be the same or may be different.

[0041] EPC 160 may include a 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 be in communication with a Home Subscriber Server (HSS) 174. MME 162 is a control node that processes signaling between UE 104 and EPC 160. Generally, MME 162 provides bearer and connection management. All User Internet Protocol (IP) packets are routed through Serving Gateway 166, which is itself connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation and other functions. PDN Gateway 172 and BM-SC 170 are connected to IP services 176. IP services 176 may include the Internet, intranet, IP Multimedia Subsystem (IMS), PS streaming services, and / or other IP services. BM-SC 170 may provide functions for MBMS user service provisioning and delivery. BM-SC 170 may act as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and may be used to schedule MBMS transmissions. MBMS Gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area for a particular broadcast service, and may be responsible for session management (start / stop) and for collecting eMBMS-related charging information.

[0042] The core network 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may communicate with a Unified Data Management (UDM) 196. The AMF 192 is a control node that processes signaling between the UE 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All User Internet Protocol (IP) packets are routed through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), Packet-Switched (PS) Streaming (PSS) services, and / or other IP services.

[0043] The base station may include and / or be referred to as a gNB, Node B, eNB, access point, base transceiver station, radio base station, radio transceiver, transceiver function, Basic Service Set (BSS), Extended Service Set (ESS), Transmission and Reception Point (TRP), or some other suitable term. The base station 102 provides an access point for the UE 104 to the EPC 160 or the core network 190. Examples of the UE 104 include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptop devices, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet devices, smart devices, wearable devices, vehicles, electricity meters, gas pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other similar functional devices. Some UEs 104 may be referred to as IoT devices (e.g., parking meters, fuel pumps, ovens, vehicles, heart monitors, etc.). The UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term.

[0044] Referring again to Figure 1 , in some aspects, the UE 104 may be configured to select a random access configuration from multiple random access configurations that provide coverage enhancement in a two-step random access procedure. For example, Figure 1The UE 104 includes a selection component 198 configured to select one of a plurality of random access configurations. The plurality of random access configurations may be part of random access configuration information received from a base station. The UE 104 may be configured to select one random access configuration from the plurality of random access configurations that optimizes and / or enhances coverage for a two-step RACH procedure. The UE 104 may generate a first random access message having a preamble and a payload based on the selected random access configuration. The UE 104 may transmit the first random access message to the base station to initiate a random access procedure.

[0045] Referring again to Figure 1 , in some aspects, the base station 102 / 180 may be configured to provide the UE with random access configuration information including a plurality of random access configurations, which may enhance coverage for a two-step RACH procedure for UEs having limited coverage during the two-step RACH procedure. For example, Figure 1 the base station 102 / 180 includes a configuration component 199 configured to transmit the random access configuration information. The random access configuration information may include a plurality of random access configurations that provide coverage enhancements that may be utilized by UEs having limited coverage during the two-step RACH procedure. The base station 102 / 180 may receive the first random access message from the UE 104 to initiate a random access procedure, the first random access message including a preamble and a payload, wherein the preamble and payload are configured based on one of the plurality of random access configurations. The base station 102 / 180 may process the first random access message. The base station 102 / 180 may generate a second random access message in response to the first random access message. The base station 102 / 180 may transmit the second random access message to the UE.

[0046] Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar fields such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0047] Figure 2A FIG. 200 is an illustration of an example of a first subframe within a 5G / NR frame structure. Figure 2B FIG. 230 is an illustration of an example of DL channels within a 5G NR subframe. Figure 2C FIG. 250 is an illustration of an example of a second subframe within a 5G NR frame structure. Figure 2DFIG. 280 is an illustration showing an example of UL channels within a 5G NR subframe. The 5G NR frame structure can be Frequency Division Duplexing (FDD), where for a particular subcarrier set (carrier system bandwidth), the subframes within that subcarrier set are dedicated to DL or UL; or it can be Time Division Duplexing (TDD), where for a particular subcarrier set (carrier system bandwidth), the subframes within that subcarrier set are dedicated to both DL and UL. In the example provided by Figure 2A , 2C , the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (mostly DL) and subframe 3 is configured with slot format 34 (mostly UL), where D is DL, U is UL, and F is for flexible use between DL / UL. Although subframes 3 and 4 are shown as having slot formats 34 and 28 respectively, any particular subframe can be configured with any one of the various available slot formats 0 - 61. Slot formats 0 and 1 are all-DL and all-UL respectively. The other slot formats 2 - 61 include a mixture of DL, UL, and flexible symbols. The UE is configured with a slot format by the received Slot Format Indicator (SFI) (configured dynamically via Downlink Control Information (DCI), or semi-statically / statically via Radio Resource Control (RRC) signaling). Note that the following description also applies to a 5G NR frame structure that is TDD.

[0048] Other wireless communication technologies may have different frame structures and / or different channels. One frame (10 ms) can be divided into 10 equal-sized subframes (1 ms). Each subframe may include one or more time slots. A subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each time slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each time slot may include 14 symbols, while for slot configuration 1, each time slot may include 7 symbols. The symbols on the DL can be Cyclic Prefix (CP) OFDM (CP-OFDM) symbols. The symbols on the UL can be CP-OFDM symbols (for high throughput scenarios) or Discrete Fourier Transform (DFT) spread 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 slot configuration and numerology. For slot configuration 0, different numerologies μ0 to 4 allow 1, 2, 4, 8, 16, and 32 time slots per subframe respectively. For slot configuration 1, different numerologies 0 to 2 allow 2, 4, and 8 time slots per subframe respectively. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols per time slot and 2μ time slots per subframe. The subcarrier spacing and symbol length / duration vary depending on the numerology. The subcarrier spacing can be equal to 2 μ*15 kHz, where μ is a parameter design from 0 to 4. Thus, the parameter design μ = 0 has a subcarrier spacing of 15 kHz, while the parameter design μ = 4 has a subcarrier spacing of 240 kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figures 2A - 2D An example is provided of a time slot configuration 0 with 14 symbols per time slot and a parameter design μ = 2, and each subframe has 4 time slots. The time slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency division multiplexed (see Figure 2B ). Each BWP may have a specific parameter design.

[0049] A resource grid can be used to represent the frame structure. Each time slot includes resource blocks (RBs) (also known as physical RBs (PRBs)) that extend over 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.

[0050] As Figure 2A explained, some REs carry reference (pilot) signals (RSs) for the UE. The RSs can include demodulation RSs (DM-RSs) for channel estimation at the UE (denoted as Rx for a particular configuration, where 100x is the port number, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RSs). The RSs can also include beam measurement RSs (BRSs), beam refinement RSs (BRRSs), and phase tracking RSs (PT-RSs).

[0051] Figure 2BExamples of various DL channels within a subframe of a decoded frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including 9 resource element groups (REGs), each REG including 4 consecutive resource elements (REs) in an OFDM symbol. The PDCCH within a BWP may be referred to as a control resource set (CORESET). Additional BWPs may be located at higher and / or lower frequencies across the channel bandwidth. The primary synchronization signal (PSS) may be within symbol 2 of a specific subframe of a frame. The PSS is used by the UE 104 to determine subframe / symbol timing and the physical layer identity. The secondary synchronization signal (SSS) may be within symbol 4 of a specific subframe of a 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 the physical layer cell identity group number, the UE may determine the physical cell identifier (PCI). Based on the PCI, the UE may determine the location of the aforementioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) may be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of resource blocks (RBs) in the system bandwidth and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted via the PBCH (such as system information blocks (SIBs)), and paging messages.

[0052] As explained in Figure 2C Some resource elements carry DM-RS for channel estimation at the base station (indicated as R for one specific configuration, but other DM-RS configurations are possible). The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the previous one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether a short PUCCH or a long PUCCH is transmitted and depending on the specific PUCCH format used. The UE may transmit sounding reference signals (SRS). The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and the UE may transmit the SRS on one of the combs. The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0053] Figure 2DExamples of various UL channels within a subframe of a decoded frame. The PUCCH may be located at the position indicated in one configuration. The PUCCH carries uplink control information (UCI), such as a scheduling request, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and a hybrid automatic repeat request (HARQ) ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0054] Figure 3 is a block diagram of a base station 310 and a UE 350 in communication in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with the broadcast of 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 reports; PDCP layer functionality associated with header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functionality associated with the mapping between logical channels and transport channels, multiplexing MAC SDUs onto transport blocks (TBs), demultiplexing MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel priority differentiation.

[0055] The transmit (TX) processor 316 and the receive (RX) processor 370 implement the layer 1 functionality associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on 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. The TX processor 316 handles 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 shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a stream of time-domain OFDM symbols. The OFDM stream is space precoded to generate multiple spatial streams. Channel estimates from the channel estimator 374 may be used to determine the encoding and modulation schemes and for spatial processing. The channel estimates may be derived from reference signals transmitted by the UE 350 and / or channel status feedback. Each spatial stream is then provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX modulates an RF carrier with the corresponding spatial stream for transmission.

[0056] At the 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 the RX processor 356 implement the layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If there are multiple spatial streams destined for the UE 350, they may 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 includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, as well as the reference signal, are recovered and demodulated by determining the signal constellation points most likely transmitted by the base station 310. These soft decisions may be based on the channel estimates calculated by the channel estimator 358. These soft decisions are then decoded and deinterleaved to recover the original data and control signals transmitted by the base station 310 on the physical channel. These data and control signals are then provided to the controller / processor 359 that implements layer 3 and layer 2 functionality.

[0057] 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 between transport channels and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0058] Similar to the functionality described in connection with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) capture, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0059] Channel estimates derived by the channel estimator 358 from reference signals or feedback transmitted by the base station 310 may be used by the TX processor 368 to select an appropriate coding and modulation scheme and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

[0060] UL transmissions are processed at the base station 310 in a manner similar to that described in connection with the receiver functionality at the UE 350. Each receiver 318RX receives signals via its respective antenna 320. Each receiver 318RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0061] 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 between transport channels and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the UE 350. The 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 the ACK and / or NACK protocols to support HARQ operations.

[0062] At least one of the TX processor 368, RX processor 356, and controller / processor 359 may be configured to perform aspects associated with Figure 1 198.

[0063] At least one of the TX processor 316, RX processor 370, and controller / processor 375 may be configured to perform aspects associated with Figure 1 199.

[0064] The UE may execute a two-step RACH procedure to acquire uplink synchronization and / or acquire an uplink grant for the network. Figure 4 Illustrates an example communication flow 400 between a UE 402 and a base station 404 as part of a two-step random access procedure. Before starting the two-step RACH procedure, the UE may receive random access configuration information 406 from the base station. For example, the UE may receive an SSB, SIB, and / or reference signal broadcast by the base station. The UE may process these signals and channels and determine the configuration for the two-step RACH. For example, the UE may determine at 408 any of the following: downlink synchronization based on at least one of the SSB, SIB, or reference signal; decoded information, or other measurement information for random access to the base station 404. The configuration for random access may include a messaging channel structure and other related procedures. This configuration information may be carried by system information. In some aspects, such as when the UE is RRC connected, the configuration information for the two-step RACH procedure may be carried by both the SIB and the SSB. After the UE obtains the configuration information, the UE may generate and transmit a step 1 transmission. The step 1 transmission may include an uplink transmission from the UE 402 to the base station 404. The step 1 transmission may be referred to as a msgA transmission. The msgA transmission may include two parts, a preamble 410 and a payload 412. The preamble 410 may be transmitted first, followed by the payload 412. The payload may include a certain MAC-CE, RRC messaging, or data.

[0065] When msgA arrives at the base station, the base station will first process the preamble at 414 and then process the payload at 464. For example, if the processing of the preamble is successful, the base station may continue to process the payload. The base station 404 may then generate a step 2 transmission and transmit it to the UE 402. The step 2 transmission may be referred to as a msgB transmission. When the preamble 410 and the payload 412 are successfully decoded, the msgB 418 transmitted by the base station to the UE may include contention resolution information. The contention resolution information may include or be based on the unique identifier of the UE.

[0066] 5G NR may initially support 5G UEs (e.g., high-end UEs such as those supporting eMBB or URLLC services), but may also support non-high-end UEs or NR reduced-capability UEs (e.g., mid-range and / or low-end UEs). Some examples of NR reduced-capability UEs may include smart wearable devices, industrial sensors, video surveillance / monitoring. NR reduced-capability UEs or non-high-end UEs may have a lower transmit power than high-end UEs (e.g., the NR reduced-capability UE is 14 dBm while the high-end or NR UE has 20 dBm or higher). NR reduced-capability UEs may also have some hardware limitations compared to high-end UEs, such as but not limited to a reduced or limited number of receive / transmit antennas, or may have a narrow transmit / receive bandwidth. Additionally, some NR reduced-capability UEs may be stationary devices and / or may be located in poor or reduced coverage locations (e.g., basements). Thus, it is very likely that NR reduced-capability UEs or non-high-end UEs will have limited coverage during the RACH procedure. Thus, it would be advantageous to provide coverage enhancement for the two-step RACH procedure for NR reduced-capability UEs or non-high-end UEs while accounting for the coexistence between the two-step RACH processes for high-end UEs and NR reduced-capability UEs.

[0067] Figure 5The logical channel structure of msgA 502 is shown. MsgA in illustration 500 includes two parts, a msgA preamble 504 and a msgA payload 506. MsgA further includes a guard band 508. Additionally, each of the preamble and the payload may include a guard time 410 (GT) at the end of the transmission. The length of the guard time 410 is represented by TG. Between the preamble 504 and the payload 506 is a transmission gap 512 (TxG). The length of the TxG 512 is represented by Tg. This value of the TxG can be configurable. For example, in some aspects, such as for low latency scenarios, the TxG can be set to zero. In other aspects, such as when the preamble and the payload use different parameter designs of different bandwidth parts (BWPs), they may have different power control schemes. Including the TxG can serve as a tuning gap between the preamble and the payload. The time durations of the preamble, the payload, and the transmission gap can be specified based on a reference subcarrier spacing (SCS), which refers to the parameter design of the carrier. This SCS can be hard-coded or in the system information (SI) or broadcast. For example, different reference SCSs can be supported in FR1 and FR2. For example, the reference SCS in FR1 can be 15 kHz, and the reference SCS in FR2 can be 60 kHz or 120 kHz. The actual parameter design used by the preamble and / or the payload is broadcast in the SI or RRC, which can be different from the reference SCS. When the guard time and the guard band are configured for payload transmission, the time duration and the bandwidth can also be specified based on the reference SCS. In some aspects, the time duration of the transmission gap and the guard time can be N symbols, and the BW of the guard band can be M frequency bins.

[0068] Figure 6FIG. is a diagram illustrating examples 600 and 620 of time-frequency resource mapping. In example 600, msgA 602 has an initial UL BWP for transmitting msgA 602 on the uplink to a base station. MsgB 604 has an initial DL BWP for transmitting msgB 604 on the downlink to a UE. In some aspects, as shown in example 600, the initial UL BWP of msgA 602 and the initial DL BWP of msgB 604 are different such that msgA 602 and msgB 604 have a frequency relationship 606. In some aspects, some restrictions on the frequency resource allocation between msgA and msgB may be introduced such that the UE does not need to retune between msgA transmission and / or msgB reception. In some aspects, the frequency relationship 606 or frequency difference between the initial UL BWP by which msgA is transmitted and the initial DL BWP by which msgB is received may be less than a threshold frequency difference. In some aspects, the threshold frequency difference may be 0 or several RBs. In some aspects, the threshold frequency difference may be within the range of RBs (e.g., [-6,6]). However, the present disclosure is not intended to be limited to the aspects disclosed herein, and thus the range may be greater than or less than [-6,6]. The frequency relationship 606 being less than the threshold frequency difference may minimize the amount of retuning required by the UE between the transmission of msgA and the reception of msgB, which may reduce implementation complexity. In some aspects, for example, as shown in example 620, the threshold frequency difference may be zero. In these aspects, the initial UL BWP by which msgA is transmitted and the initial DL BWP by which msgB is received are the same. In some aspects, the respective BWPs of msgA and msgB may have the same center frequency such that the UE does not need to retune.

[0069] Figure 7 is a call flow diagram illustrating an example of a two-step RACH procedure according to some aspects of the present disclosure. Figure 7 The diagram 700 includes a UE 702 and a base station 704. The base station 704 may be configured to provide a cell. For example, in Figure 1 the context of, the base station 704 may correspond to base station 102 / 180, and correspondingly, the cell may include a geographic coverage area 110 where communication coverage is provided and / or a small cell 102' having a coverage area 110'. Additionally, the UE 702 may correspond to at least UE104. In another example, in Figure 3 the context of, the base station 704 may correspond to base station 310, and the UE 702 may correspond to UE 350. Optional aspects are illustrated with dashed lines.

[0070] The UE 702 may perform a two-step RACH procedure to acquire uplink synchronization, acquire an uplink grant for the network, and / or transmit a payload to the network.

[0071] Before starting the two-step RACH procedure, the UE 702 may receive random access configuration information 706 from the base station 704. The random access configuration information 706 may include multiple random access configurations. The random access configuration information may be transmitted by the base station to the UE in the form of a downlink reference signal (RS) and / or a physical channel (such as a synchronization signal block (SSB) or a system information block (SIB)). The UE may receive and process the random access configuration information to determine the configuration applicable to the two-step RACH procedure.

[0072] In some aspects, for example, to determine the configuration for the two-step RACH procedure, the UE may be configured to determine at least one of the following at 708: reference signal (RS) signal-to-noise ratio (SNR), RS signal-to-interference-plus-noise ratio (SINR), reference signal received power (RSRP), or reference signal received quality (RSRQ). The UE may be configured to use this determination to determine the configuration for the two-step RACH procedure.

[0073] At 710, the UE may be configured to select one random access configuration from the multiple random access configurations. In some aspects, the UE may select one random access configuration from the multiple random access configurations based on the cell coverage of the UE or the synchronization signal block (SSB) RSRP measurement. For example, a UE in good cell coverage may select a first random access configuration applicable to a UE in a good coverage area, while a UE in poor cell coverage or at the edge of cell coverage may select a second random access configuration that is configured to account for poor or reduced coverage and includes parameters to compensate for the reduced coverage.

[0074] At 712, the UE may generate a first random access message including a preamble and a payload. In some aspects, the preamble and the payload of the first random access message may be generated based on the random access configuration selected by the UE.

[0075] At 714, the UE may transmit a first random access message to the base station 704. The UE transmits a first random access message including a preamble and a payload to initiate a random access procedure. In some aspects, the plurality of random access configurations may incorporate additional parameters in addition to those parameters for the conventional two-step RACH procedure for a conventional UE (e.g., a high-end UE, supporting enhanced mobile broadband (eMBB) or ultra-reliable low-latency communication (URLLC) services). For example, the plurality of random access configurations may incorporate additional parameters for the preamble and / or payload for non-high-end UEs or mid-range and / or low-range UEs (such as, but not limited to, smart wearable devices, industrial sensors, video surveillance / monitoring) to transmit the first random access message. For example, the parameters may include at least one of the following: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmit power of the preamble, or power control step size. In another example, the parameters may include at least one of the following: PUSCH resource unit, PUSCH waveform, PUSCH initial transmit power, frequency hopping pattern, repetition factor, modulation and coding scheme, or power control step size. In some aspects, the preamble and payload of the first random access message are transmitted on the same transmit beam. In some aspects, at least one of the plurality of random access configurations may include contention-based parameters for transmitting the first random access message in a contention-based random access procedure. In some aspects, some UEs (e.g., non-high-end UEs) may reuse the existing configuration of the two-step RACH for high-end UEs with some additional contention-based parameters added. For example, the contention-based parameters may include at least one of the following: physical random access channel (PRACH) repetition, physical uplink shared channel (PUSCH) repetition, power boost for PRACH or PUSCH, power control step size, or a combination thereof. In such aspects, the first random access message may be transmitted on a resource allocated to a set of UEs for a contention-based random access procedure. In some aspects, contention-free RACH may be supported for non-high-end UEs such that at least one of the plurality of random access configurations may include contention-free parameters for transmitting the first random access message in a contention-free random access procedure. For example, the contention-free parameters may include at least one of the following: PRACH repetition, PUSCH repetition, power boost for PRACH or PUSCH, power control step size, or a combination thereof. In these aspects, the first random access message may be transmitted on a resource specifically allocated to the UE for a contention-free random access procedure. In some aspects, certain random access configurations may be configured to support a transmit beam change between the preamble and payload of the first random access message. For example, in some aspects, the beam (e.g., spatial uplink filter) for transmitting the payload of the first random access message may be the same as the beam for transmitting the preamble.In some aspects, the UE may be configured to use different transmit beams when transmitting a preamble and when transmitting a payload. However, in some aspects, the UE may be configured to use the same beam to transmit the preamble and the payload such that beam switching between the preamble and the payload may be prohibited for non-high-end UEs. Disabling beam switching allows for a reduction in implementation complexity for non-high-end UEs.

[0076] The base station 704 may receive a first random access message from the UE that includes a preamble and a payload. The configuration of the preamble and the payload may be based on one of a plurality of random access configurations. After receiving the first random access message, the base station 704 may process the first random access message at 716.

[0077] At 718, the base station may generate a second random access message. The base station generates the second random access message in response to the first random access message. The base station may generate the second random access message after processing the preamble and the payload of the first random access message.

[0078] At 720, the base station may transmit the second random access message to the UE. In some aspects, the PDCCH of the second random access message may be transmitted based on a subset of the PDCCH AL in response to the first random access message. For example, the subset of the PDCCH AL may include at least one of AL8 or AL16. In some aspects, the PDSCH of the second random access message may be transmitted in response to the first random access message. In some aspects, the PDSCH may be transmitted based on PDSCH repetition.

[0079] At 722, the UE may be configured to receive the PDCCH of the second random access message. The UE may be configured to receive the PDCCH of the second random access message using blind detection based on a subset of the PDCCH AL (such as, for example, at least one of AL8 or AL16). In some aspects, the PDCCH AL may be limited to AL8 and AL16. Limiting the subset of the PDCCH AL to AL8 or AL16 allows for an extension of the PDCCH coverage and a reduction in UE complexity in PDCCH detection.

[0080] At 724, the UE may be configured to receive the PDSCH of the second random access message. The UE receives the PDSCH of the second random access message in response to the first random access message. In some aspects, the frequency difference between a first frequency on which the first random access message is transmitted and a second frequency on which the second random access message is received is less than a threshold frequency difference. In some aspects, the threshold frequency difference between the first frequency on which the first random access message is transmitted and the second frequency on which the second random access message is received is zero. In these aspects, the first frequency on which the first random access message is transmitted and the second frequency on which the second random access message is received are the same.

[0081] At 726, the UE may be configured to determine a PDSCH repetition configuration. In some aspects, the PDSCH may be received by the UE based on PDSCH repetition. Determining the PDSCH repetition configuration may allow for extended PDSCH coverage. In some aspects, the PDSCH repetition configuration may be indicated in the PDCCH, may be fixed for non-high-end UEs, or may be RRC-configured.

[0082] Figure 8 FIG. 800 is a flow diagram of a wireless communication method. The method may be performed by a UE or a component of the UE (e.g., UE 104, 402, 702; apparatus 902; cellular baseband component 904, which may include memory 360 and may be the entire UE 350 or a component of UE 350, such as TX processor 368, RX processor 356, and / or controller / processor 359). In accordance with various aspects, one or more of the illustrated operations of method 800 may be omitted, transposed, and / or performed concurrently. The UE may implement the method in FIG. 700. Optional aspects are illustrated with dashed lines. The method may enable the UE to select a random access configuration that may provide coverage enhancement for a two-step RACH procedure.

[0083] At 802, the UE may receive random access configuration information. For example, 802 may be performed by configuration component 940 of apparatus 902. The UE may receive the random access configuration information from a base station. The random access configuration information may include a plurality of random access configurations.

[0084] In some aspects, e.g., at 804, the UE may determine at least one of RS SNR, RS SINR, RSRP, or RSRQ. For example, 804 may be performed by determination component 942 of apparatus 902. In some aspects, the UE may select one of the plurality of random access configurations based on the determination of at least one of RS SNR, RS SINR, RSRP, or RSRQ.

[0085] At 806, the UE may select one of the plurality of random access configurations. For example, 806 may be performed by selection component 944 of apparatus 902. In some aspects, the UE may select one of the plurality of random access configurations based on the cell quality of the UE or an SSB RSRP measurement.

[0086] At 808, the UE may generate a first random access message having a preamble and a payload. For example, 808 may be performed by generation component 946 of apparatus 902. In some aspects, the first random access message may be generated based on the selected random access configuration.

[0087] At 810, the UE may transmit a first random access message to the base station. For example, 810 may be performed by the RACH component 948 of the equipped 902. The UE may transmit a first random access message to the base station to initiate a random access procedure. In some aspects, the plurality of random access configurations may include parameters for transmitting the first random access message. These parameters may include at least one of the following: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmission power of the preamble, or power control step size. In some aspects, the plurality of random access configurations include parameters for transmitting the first random access message. These parameters may include at least one of the following: PUSCH resource unit, PUSCH waveform, initial transmission power of PUSCH, hopping pattern, repetition factor, modulation and coding scheme, or power control step size. The parameters for transmitting the first random access message may be applied to the preamble or payload of the first random access message. In some aspects, the preamble and payload of the first random access message are transmitted on the same transmit beam.

[0088] In some aspects, at least one of the plurality of random access configurations may include contention-based parameters for transmitting the first random access message in a contention-based random access procedure. For example, the contention-based parameters may include at least one of the following: PRACH repetition, PUSCH repetition, power boost for PRACH or PUSCH, power control step size, or a combination thereof. In some aspects, the first random access message may be transmitted on a resource allocated to a set of UEs for a contention-based random access procedure. In some aspects, at least one of the plurality of random access configurations may include contention-free parameters for transmitting the first random access message in a contention-free random access procedure. For example, the contention-free parameters may include at least one of the following: PRACH repetition, PUSCH repetition, power boost for PRACH or PUSCH, power control step size, or a combination thereof. In these aspects, the first random access message may be transmitted on a resource specifically allocated to the UE for a contention-free random access procedure.

[0089] In some aspects, such as at 812, the UE may receive the PDCCH of the second random access message. For example, 812 may be performed by the PDCCH component 950 of the equipped 902. The UE may receive the PDCCH of the second random access message by using blind detection based on a subset of the PDCCH aggregation level (AL) in response to the first random access message. In some aspects, the subset of the PDCCH AL may include at least one of AL8 or AL16.

[0090] In some aspects, such as at 814, the UE may receive the PDSCH of the second random access message. For example, 812 may be performed by the PDSCH component 952 of the device 902. The UE may receive the PDSCH of the second random access message in response to the first random access message. In some aspects, the frequency difference between the first frequency used to transmit the first random access message and the second frequency used to receive the second random access message is less than a threshold frequency difference. In some aspects, the threshold frequency difference between the first frequency used to transmit the first random access message and the second frequency used to receive the second random access message is zero. In these aspects, the first frequency used to transmit the first random access message and the second frequency used to receive the second random access message are the same.

[0091] In some aspects, such as at 816, the UE may determine the PDSCH repetition configuration. For example, 816 may be performed by the repetition component 954 of the device 902. In some aspects, the PDSCH may be received by the UE based on the PDSCH repetition.

[0092] Figure 9FIG. 900 is a diagram illustrating an example of a hardware implementation of apparatus 902. The apparatus 902 is a UE and includes a cellular baseband processor 904 (also referred to as a modem) coupled to a cellular RF transceiver 922 and one or more subscriber identity module (SIM) cards 920, an application processor 906 coupled to a secure digital (SD) card 908 and a screen 910, a Bluetooth module 912, a wireless local area network (WLAN) module 914, a global positioning system (GPS) module 916, and a power supply 918. The cellular baseband processor 904 communicates with the UE 104 and / or the BS 102 / 180 via the cellular RF transceiver 922. The cellular baseband processor 904 may include a computer-readable medium / memory. The computer-readable medium / memory may be non-transitory. The cellular baseband processor 904 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the cellular baseband processor 904, causes the cellular baseband processor 904 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 904 when executing the software. The cellular baseband processor 904 further includes a receiving component 930, a communication manager 932, and a transmitting component 934. The communication manager 932 includes one or more of the illustrated components. The components within the communication manager 932 may be stored in the computer-readable medium / memory and / or configured as hardware within the cellular baseband processor 904. The cellular baseband processor 904 may be a component of the UE 350 and may include a memory 360 and / or at least one of the following: a TX processor 368, an RX processor 356, and a controller / processor 359. In one configuration, the apparatus 902 may be a modem chip and include only the baseband processor 904, and in another configuration, the apparatus 902 may be the entire UE (e.g., see Figure 3 of 350) and include the aforementioned additional modules of the apparatus 902.

[0093] The communication manager 932 includes a configuration component 940 configured to receive random access configuration information, e.g., as described in conjunction with Figure 8 of 802. The communication manager 932 further includes a determination component 942 configured to determine at least one of RS SNR, RS SINR, RSRP, or RSRQ, e.g., as described in conjunction with Figure 8 of 804. The communication manager 932 further includes a selection component 944 configured to select one random access configuration from a plurality of random access configurations, e.g., as described in conjunction with Figure 8 of 806. The communication manager 932 further includes a generation component 946 configured to generate a first random access message having a preamble and a payload, e.g., as described in conjunction with Figure 8as described in 808 of. The communication manager 932 further includes a RACH component 948 configured to transmit a first random access message to a base station, e.g., as described in conjunction with Figure 8 as described in 810 of. The communication manager 932 further includes a PDCCH component 950 configured to receive a PDCCH of a second random access message, e.g., as described in conjunction with Figure 8 as described in 812 of. The communication manager 932 further includes a PDSCH component 952 configured to receive a PDSCH of a second random access message, e.g., as described in conjunction with Figure 8 as described in 814 of. The communication manager 932 further includes a repetition component 954 configured to determine a PDSCH repetition configuration, e.g., as described in conjunction with Figure 8 as described in 816 of.

[0094] The apparatus may include additional components that perform each block of the algorithm in the foregoing flowchart of Figure 8 Thus, Figure 8 each block in the foregoing flowchart of may be performed by a component and the device may include one or more of those components. These components may 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 implementation by a processor, or some combination thereof.

[0095] In one configuration, apparatus 902, specifically the cellular baseband processor 904, includes means for receiving random access configuration information from a base station, the random access configuration information including a plurality of random access configurations. The apparatus includes means for the UE to select one of the plurality of random access configurations. The apparatus includes means for generating a first random access message having a preamble and a payload based on the selected random access configuration. The apparatus includes means for transmitting the first random access message to the base station to initiate a random access procedure. The apparatus further includes means for determining at least one of RSSNR, RS SINR, RSRP, or RSRQ. The UE selects one of the plurality of random access configurations based on the determination. The apparatus further includes means for receiving, in response to the first random access message, a PDCCH of a second random access message using blind detection based on a subset of PDCCH AL. The apparatus further includes means for receiving, in response to the first random access message, a PDSCH of the second random access message. The apparatus further includes means for determining a PDSCH repetition configuration, wherein the PDSCH is received based on the PDSCH repetition. The foregoing means may be one or more of the foregoing components in apparatus 902 configured to perform the functions recited by the foregoing means. As described above, device 902 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Thus, in one configuration, the foregoing means may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions recited by the foregoing means.

[0096] Figure 10 is a flow chart 1000 of a wireless communication method. The method may be performed by a base station or a component of a base station (e.g., base station 102 / 180, 404, 704; apparatus 1102; baseband unit 1104, which may include a memory 376 and which may be the entire base station 310 or a component of base station 310 (such as TX processor 316, RX processor 370, and / or controller / processor 375)). According to various aspects, one or more of the illustrated operations of method 1000 may be omitted, transposed, and / or performed concurrently. The base station may implement the method of FIG. 700. The method may enable the base station to provide a plurality of random access configurations to a UE that may provide coverage enhancement for a two-step RACH procedure.

[0097] At 1002, the base station may transmit random access configuration information for a random access procedure. For example, 1002 may be performed by the configuration component 1140 of apparatus 1102. The random access configuration information may include a plurality of random access configurations.

[0098] At 1004, the base station may receive a first random access message to initiate a random access procedure. For example, 1004 may be performed by the first random access message component 1142 of the device 1102. The base station may receive the first random access message from the UE. The first random access message may include a preamble and a payload. In some aspects, the configuration of the preamble and the payload may be based on one of a plurality of random access configurations. In some aspects, the plurality of random access configurations includes parameters for transmitting the first random access message. For example, the parameters may include at least one of the following: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmission power of the preamble, or power control step size. In some aspects, the parameters may include at least one of the following: PUSCH resource unit, PUSCH waveform, initial transmission power of PUSCH, frequency hopping pattern, repetition factor, modulation and coding scheme, or power control step size. In some aspects, the preamble and the payload of the first random access message are received on the same receiving beam. In some aspects, at least one of the plurality of random access configurations includes contention-based parameters for transmitting the first random access message in a contention-based random access procedure. For example, the contention-based parameters may include at least one of PRACH repetition, PUSCH repetition, power boost for PRACH or PUSCH, power control step size, or a combination thereof, such that the first random access message is transmitted on resources allocated to a set of UEs for a contention-based random access procedure. In some aspects, at least one of the plurality of random access configurations includes contention-free parameters for transmitting the first random access message in a contention-free random access procedure. For example, the contention-based parameters may include at least one of PRACH repetition, PUSCH repetition, power boost for PRACH or PUSCH, power control step size, or a combination thereof, such that the first random access message is transmitted on resources specifically allocated to the UE for a contention-free random access procedure. In some aspects, the frequency difference between the first frequency at which the first random access message is received and the second frequency at which the second random access message is transmitted is less than a threshold frequency difference. In some aspects, the threshold frequency difference is zero, such that the first frequency at which the first random access message is received and the second frequency at which the second random access message is transmitted are the same.

[0099] At 1006, the base station may process the first random access message. For example, 1006 may be performed by the processing component 1144 of the device 1102. In some aspects, the base station may process the preamble of the first random access message, and upon detecting the preamble, the base station may then process the payload of the first random access message.

[0100] At 1008, the base station may generate a second random access message. For example, 1008 may be performed by the generation component 1146 of the equipped 1102. The base station generates a second random access message in response to the first random access message. The base station may generate the second random access message after processing the preamble and payload of the first random access message.

[0101] At 1010, the base station may transmit the second random access message to the UE. For example, 1010 may be performed by the second random access message component 1148 of the equipped 1102. In some aspects, the PDCCH of the second random access message may be transmitted based on a subset of the PDCCH AL in response to the first random access message. For example, the subset of the PDCCH AL may include at least one of AL8 or AL16. In some aspects, the PDSCH of the second random access message may be transmitted in response to the first random access message. In some aspects, the PDSCH may be transmitted based on PDSCH repetition.

[0102] Figure 11 FIG. 1100 is a diagram illustrating an example of a hardware implementation of the equipped 1102. The equipped 1102 is a BS and includes a baseband unit 1104. The baseband unit 1104 may communicate with the UE 104 via a cellular RF transceiver. The baseband unit 1104 may include a computer-readable medium / memory. The baseband unit 1104 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the baseband unit 1104, causes the baseband unit 1104 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the baseband unit 1104 when executing the software. The baseband unit 1104 further includes a receiving component 1130, a communication manager 1132, and a transmission component 1134. The communication manager 1132 includes one or more of the illustrated components. The components within the communication manager 1132 may be stored in the computer-readable medium / memory and / or configured as hardware within the baseband unit 1104. The baseband unit 1104 may be a component of the BS 310 and may include a memory 376 and / or at least one of the following: a TX processor 316, an RX processor 370, and a controller / processor 375.

[0103] The communication manager 1132 includes a configuration component 1140 that may transmit random access configuration information for a random access procedure, e.g., as described in Figure 10 in connection with 1002. The communication manager 1132 further includes a first random access message component 1142 that may receive a first random access message to initiate a random access procedure, e.g., as described in Figure 10 in connection with 1004. The communication manager 1132 further includes a processing component 1144 that may process the first random access message, e.g., as described in connection withFigure 10 as described in 1006. The communication manager 1132 further includes a generating component 1146 that can generate a second random access message, e.g., as described in conjunction with Figure 10 1008. The communication manager 1134 further includes a second random access message component 1148 that can transmit the second random access message to the UE, e.g., as described in conjunction with Figure 10 1010.

[0104] The apparatus may include additional components that execute each block of the algorithm in the Figure 10 foregoing flowchart. Thus, Figure 10 each block in the foregoing flowchart may be executed by a component and the device may include one or more of those components. These components may 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 implementation by a processor, or some combination thereof.

[0105] In one configuration, the apparatus 1102, specifically the baseband unit 1104, includes means for transmitting to the UE random access configuration information for a random access procedure, where the random access configuration information includes a plurality of random access configurations. The apparatus includes means for receiving from the UE a first random access message to initiate the random access procedure, the first random access message including a preamble and a payload, where the preamble and payload are configured based on one of the plurality of random access configurations. The apparatus includes means for processing the first random access message. The apparatus includes means for generating a second random access message in response to the first random access message. The apparatus includes means for transmitting the second random access message to the UE. The foregoing means may be one or more of the foregoing components in the apparatus 1102 configured to perform the functions recited by the foregoing means. As described above, the device 1102 may include a TX processor 316, an RX processor 370, and a controller / processor 375. Thus, in one configuration, the foregoing means may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the foregoing means.

[0106] The present disclosure relates to coverage enhancement for a two-step RACH procedure for non-high-end or low-end UEs (e.g., NR reduced-capability UEs). These low-end devices cannot be configured to support the two-step RACH procedure utilized by high-end devices (e.g., NR UEs) due to, for example, transmit power limitations or hardware limitations. Additionally, low-end devices are likely to have limited coverage during the two-step RACH procedure. Aspects presented herein provide a solution to the coverage limitation problem for low-end UEs during the two-step RACH procedure by improving the way the two-step RACH procedure is configured for low-end UEs. In some aspects, the configuration of the RACH procedure can be optimized by incorporating additional parameters configured for low-end UEs. At least one advantage is that the present disclosure provides random access configuration information including multiple random access configurations. The multiple random access configurations can be used by non-high-end UEs (e.g., NR reduced-capability UEs) to enhance or optimize the two-step RACH procedure. At least another advantage of the present disclosure is that the random access configuration can be configured to reduce the implementation complexity for non-high-end UEs. For example, the transmit beam switch between the preamble and the payload is prohibited for non-high-end UEs, or can be configured to use the same transmit beam to transmit the preamble and the payload. In another example, the frequency relationship between the initial UL BWP of the first random access message and the initial DL BWP of the second random access message can be minimized or zero, such that the UE does not have to retune between the transmission of the first random access message and the reception of the second random access message. Yet another advantage of the present disclosure is that the multiple random access configurations can also be utilized by high-end UEs (e.g., NR UEs) such as when the high-end UE has reduced or poor coverage.

[0107] It should be understood that the specific order or hierarchy of the various blocks in the disclosed process / flowchart is illustrative of example approaches. It should be understood that based on design preferences, the specific order or hierarchy of the various blocks in these process / flowcharts can be rearranged. Additionally, some blocks can be combined or omitted. The appended method claims present the elements of the various blocks in exemplary order and are not meant to be limited to the specific order or hierarchy presented.

[0108] The following examples are merely illustrative and can be combined with aspects of other embodiments or the teachings described herein without limitation.

[0109] Example 1 is a method for wireless communication at a UE, including:

[0110] receiving, from a base station, random access configuration information, the random access configuration information including multiple random access configurations;

[0111] selecting, by the UE, one random access configuration from the multiple random access configurations;

[0112] Generate a first random access message having a preamble and a payload based on a selected random access configuration; and

[0113] Transmit the first random access message to the base station to initiate a random access procedure.

[0114] In Example 2, the method of Example 1 further includes determining at least one of: reference signal (RS) signal-to-noise ratio (SNR), RS signal-to-interference-plus-noise ratio (SINR), reference signal received power (RSRP), or reference signal received quality (RSRQ), wherein the UE selects one random access configuration from the plurality of random access configurations based on the determination.

[0115] In Example 3, the method of Example 1 or 2 further includes: the plurality of random access configurations includes parameters for transmitting the first random access message, the parameters including at least one of: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmission power of the preamble, or power control step size.

[0116] In Example 4, the method of any one of Examples 1-3 further includes: the plurality of random access configurations includes parameters for transmitting the first random access message, the parameters including at least one of: PUSCH resource element, PUSCH waveform, initial transmission power of PUSCH, hopping pattern, repetition factor, modulation and coding scheme, or power control step size.

[0117] In Example 5, the method of any one of Examples 1-4 further includes: the preamble and the payload of the first random access message are transmitted on the same transmit beam.

[0118] In Example 6, the method of any one of Examples 1-5 further includes: at least one of the plurality of random access configurations includes contention-based parameters for transmitting the first random access message in a contention-based random access procedure, wherein the contention-based parameters include at least one of: PRACH repetition, PUSCH repetition, power boost for PRACH or PUSCH, or power control step size, wherein the first random access message is transmitted on a resource allocated to a set of UEs for a contention-based random access procedure.

[0119] In Example 7, the method of any one of Examples 1-6 further includes: at least one of the plurality of random access configurations includes contention-free parameters for transmitting the first random access message in a contention-free random access procedure, where the contention-free parameters include at least one of the following: physical random access channel (PRACH) repetition, physical uplink shared channel (PUSCH) repetition, power boost for PRACH or PUSCH, or power control step size, where the first random access message is transmitted on a resource specifically allocated to the UE for the contention-free random access procedure.

[0120] In Example 8, the method of any one of Examples 1-7 further includes: receiving a PDCCH of a second random access message based on a subset of PDCCH AL in response to the first random access message; and receiving a PDSCH of the second random access message in response to the first random access message.

[0121] In Example 9, the method of any one of Examples 1-8 further includes: the subset of PDCCH AL includes at least one of AL8 or AL16.

[0122] In Example 10, the method of any one of Examples 1-9 further includes: determining a PDSCH repetition configuration, where the PDSCH is received based on the PDSCH repetition.

[0123] In Example 11, the method of any one of Examples 1-10 further includes: the frequency difference between a first frequency by which the first random access message is transmitted and a second frequency by which the second random access message is received is less than a threshold frequency difference.

[0124] In Example 12, the method of any one of Examples 1-11 further includes: the threshold frequency difference is zero, where the first frequency by which the first random access message is transmitted and the second frequency by which the second random access message is received are the same.

[0125] Example 13 is a device that includes one or more processors and one or more memories in electronic communication with the one or more processors, where the one or more memories store instructions executable by the one or more processors to cause a system or apparatus to implement the method in any one of Examples 1-12.

[0126] Example 14 is a system or apparatus that includes means for implementing the method in any one of Examples 1-12 or for implementing the apparatus in any one of Examples 1-15.

[0127] Example 15 is a non-transitory computer-readable medium storing instructions executable by one or more processors, the instructions causing the one or more processors to implement the method in any one of Examples 1-12.

[0128] Example 16 is a method for wireless communication at a base station, including: transmitting random access configuration information for a random access procedure to a user equipment (UE), where the random access configuration information includes a plurality of random access configurations; receiving, from the UE, a first random access message to initiate the random access procedure, the first random access message including a preamble and a payload, where the configurations of the preamble and the payload are based on one of the plurality of random access configurations; processing the first random access message; generating a second random access message in response to the first random access message; and transmitting the second random access message to the UE.

[0129] In Example 17, the method of Example 16 further includes: the plurality of random access configurations includes parameters for transmitting the first random access message, the parameters including at least one of the following: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmission power of the preamble, or power control step size.

[0130] In Example 18, the method of Example 16 or 17 further includes: the plurality of random access configurations includes parameters for transmitting the first random access message, the parameters including at least one of the following: physical uplink shared channel (PUSCH) resource unit, PUSCH waveform, PUSCH initial transmission power, hopping pattern, repetition factor, modulation and coding scheme, or power control step size.

[0131] In Example 19, the method of any one of Examples 16-18 further includes: the preamble and the payload of the first random access message are received on the same receive beam.

[0132] In Example 20, the method of any one of Examples 16-19 further includes: at least one of the plurality of random access configurations includes contention-based parameters for transmitting the first random access message in a contention-based random access procedure, where the contention-based parameters include at least one of the following: physical random access channel (PRACH) repetition, physical uplink shared channel (PUSCH) repetition, power boost for PRACH or PUSCH, power control step size, where the first random access message is transmitted on a resource allocated to a set of UEs for a contention-based random access procedure.

[0133] Example 21 is an apparatus that includes one or more processors and one or more memories in electronic communication with the one or more processors, the one or more memories storing instructions executable by the one or more processors to cause a system or device to perform a method as in any of Examples 16 - 20.

[0134] Example 22 is a system or device that includes means for performing a method as in any of Examples 16 - 20 or for implementing a device as in any of Examples 16 - 20.

[0135] Example 23 is a non - transitory computer - readable medium that stores instructions executable by one or more processors, the instructions causing the one or more processors to perform a method as in any of Examples 16 - 20.

[0136] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, where the singular forms of elements are recited unless otherwise specified, are not intended to mean "one and only one" but "one or more". Terms such as "if", "when", and "while" are to be construed to mean "under the condition that", rather than implying a direct temporal relationship or reaction. That is, these phrases (e.g., "when...") do not imply an immediate action in response to the occurrence of an action or during the occurrence of an action, but only imply that an action will occur under the condition that the condition is met, without requiring a specific or immediate time constraint for the action to occur. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration". Any aspect described herein as "exemplary" need not be construed as superior or better than other aspects. Unless specifically stated otherwise, the term "some / a certain" 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 "any combination of A, B, C, or thereof" include any combination of A, B, and / or C, and may include multiple A's, multiple B's, or multiple C's. 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 "any combination of A, B, C, or thereof" can be only A, only B, only C, A and B, A and C, B and C, or A and B and C, where any such combination may include one or more members of A, B, or C. Elements of the various aspects described throughout this disclosure that are presently known or later developed by those of ordinary skill in the art that are structural and functional equivalents are hereby expressly incorporated by reference and are intended to be covered by the claims. Additionally, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is expressly recited in the claims. The terms "module", "mechanism", "element", "device", etc. may not be substitutes for the term "apparatus". Thus, no claim element should be construed as a means-plus-function unless the element is expressly recited using the phrase "means for...".

Claims

1. A method for wireless communication at a user equipment (UE), comprising: Receiving random access configuration information, the random access configuration information including a plurality of random access configurations associated with a specific type of random access procedure, each of the plurality of random access configurations indicating different random access parameters configured for different random access messages in the specific type of random access procedure; Selecting one random access configuration from the plurality of random access configurations; Generating a first random access message having a preamble and a payload based on the selected random access configuration; And Transmitting the first random access message to initiate the specific type of random access procedure.

2. The method according to claim 1, further comprising: Determining at least one of: reference signal (RS) signal-to-noise ratio (SNR), RS signal-to-interference-plus-noise ratio (SINR), reference signal received power (RSRP), or reference signal received quality (RSRQ), and selecting one random access configuration from the plurality of random access configurations based on the determination.

3. The method according to claim 1, wherein the plurality of random access configurations include parameters for transmitting the first random access message, the parameters including at least one of: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmit power of the preamble, or power control step size.

4. The method according to claim 1, wherein the plurality of random access configurations include parameters for transmitting the first random access message, the parameters including at least one of: physical uplink shared channel (PUSCH) resource element, PUSCH waveform, initial transmit power of PUSCH, hopping pattern, repetition factor, modulation and coding scheme, or power control step size.

5. The method according to claim 1, wherein the preamble and the payload of the first random access message are transmitted on the same transmit beam.

6. The method according to claim 1, wherein at least one of the plurality of random access configurations includes contention-based parameters for transmitting the first random access message in a contention-based random access procedure, the contention-based parameters including at least one of: physical random access channel (PRACH) repetition, physical uplink shared channel (PUSCH) repetition, power boost for PRACH or PUSCH, or power control step size, wherein the first random access message is transmitted on a resource allocated to a set of UEs for a contention-based random access procedure.

7. The method according to claim 1, wherein at least one of the plurality of random access configurations includes contention-free parameters for transmitting the first random access message in a contention-free random access procedure, and the contention-free parameters include at least one of the following: physical random access channel (PRACH) repetition, physical uplink shared channel (PUSCH) repetition, power boost for PRACH or PUSCH, or power control step size, and the first random access message is transmitted on a resource specifically allocated to the UE for the contention-free random access procedure.

8. The method according to claim 1, wherein the transmitting of the first random access message at a first frequency further includes: receiving a second random access message at a second frequency, the difference between the second frequency and the first frequency being within a threshold frequency difference, wherein the receiving of the second random access message includes: receiving a physical downlink control channel (PDCCH) of the second random access message based on a subset of a physical downlink control channel (PDCCH) aggregation level (AL) in response to the first random access message; and receiving a physical downlink shared channel (PDSCH) of the second random access message in response to the first random access message; and determining whether to retune between the transmitting of the first random access message and the receiving of the second random access message based on the threshold frequency difference and the frequency relationship between the first frequency and the second frequency.

9. The method according to claim 8, wherein the subset of the PDCCH AL includes at least one of AL8 or AL16.

10. The method according to claim 8, further comprising: determining a PDSCH repetition configuration, wherein the PDSCH is received based on the PDSCH repetition configuration.

11. The method according to claim 8, further comprising determining that the frequency difference between the first frequency at which the first random access message is transmitted and the second frequency at which the second random access message is received is less than the threshold frequency difference.

12. The method according to claim 11, wherein the threshold frequency difference is zero, and the first frequency at which the first random access message is transmitted is equal to the second frequency at which the second random access message is received.

13. An apparatus for wireless communication, comprising: a memory; and at least one processor, the at least one processor being coupled to the memory and configured to: receive random access configuration information, the random access configuration information including a plurality of random access configurations associated with a specific type of random access procedure, each of the plurality of random access configurations indicating different random access parameters configured for different random access messages in the specific type of random access procedure; select one random access configuration from the plurality of random access configurations; generate a first random access message having a preamble and a payload based on the selected random access configuration; and transmit the first random access message to initiate the specific type of random access procedure.

14. The apparatus according to claim 13, wherein the at least one processor is further configured to: Determine at least one of: a reference signal RS signal-to-noise ratio SNR, an RS signal-to-interference-plus-noise ratio SINR, a reference signal received power RSRP, or a reference signal received quality RSRQ, and select one of the plurality of random access configurations based on the determination.

15. The apparatus according to claim 13, wherein the plurality of random access configurations include parameters for transmitting the first random access message, the parameters including at least one of: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmission power of the preamble, or power control step size.

16. The apparatus according to claim 13, wherein the plurality of random access configurations include parameters for transmitting the first random access message, the parameters including at least one of: a physical uplink shared channel PUSCH resource element, PUSCH waveform, initial transmission power of the PUSCH, frequency hopping pattern, repetition factor, modulation and coding scheme, or power control step size.

17. The apparatus according to claim 13, wherein the preamble and the payload of the first random access message are transmitted on the same transmit beam.

18. The apparatus according to claim 13, wherein at least one of the plurality of random access configurations includes contention-based parameters for transmitting the first random access message in a contention-based random access procedure, wherein the contention-based parameters include at least one of: physical random access channel PRACH repetition, physical uplink shared channel PUSCH repetition, power boost for the PRACH or PUSCH, or power control step size, wherein the first random access message is transmitted on resources allocated to a set of UEs for the contention-based random access procedure.

19. The apparatus according to claim 13, wherein at least one of the plurality of random access configurations includes contention-free parameters for transmitting the first random access message in a contention-free random access procedure, wherein the contention-free parameters include at least one of: physical random access channel PRACH repetition, physical uplink shared channel PUSCH repetition, power boost for the PRACH or PUSCH, or power control step size, wherein the first random access message is transmitted on resources specifically allocated to the UE for the contention-free random access procedure.

20. The apparatus according to claim 13, wherein the first random access message is transmitted at a first frequency, and the at least one processor is further configured to: receive a second random access message at a second frequency, the difference between the second frequency and the first frequency being within a threshold frequency difference, wherein the at least one processor configured to receive the second random access message is further configured to: receive, in response to the first random access message, a physical downlink control channel PDCCH of the second random access message using blind detection based on a subset of a physical downlink control channel PDCCH aggregation level AL; and A physical downlink shared channel (PDSCH) that receives the second random access message in response to the first random access message.

21. The apparatus according to claim 20, wherein the subset of the PDCCH ALs includes at least one of AL8 or AL16.

22. The apparatus according to claim 20, wherein the at least one processor is further configured to: Determine a PDSCH repetition configuration, wherein the PDSCH is received based on the PDSCH repetition configuration.

23. The apparatus according to claim 20, wherein the at least one processor is further configured to determine that a frequency difference between a first frequency at which the first random access message is transmitted and a second frequency at which the second random access message is received is less than a threshold frequency difference.

24. The apparatus according to claim 23, wherein the threshold frequency difference is zero, and the first frequency at which the first random access message is transmitted is equal to the second frequency at which the second random access message is received.

25. A method for wireless communication at a network entity, comprising: Transmitting random access configuration information for a random access procedure, wherein the random access configuration information includes a plurality of random access configurations associated with a specific type of random access procedure, and each of the plurality of random access configurations indicates different random access parameters configured for different random access messages in the specific type of random access procedure; Receiving a first random access message to initiate the specific type of random access procedure, the first random access message including a preamble and a payload, wherein the preamble and the payload are configured based on one of the plurality of random access configurations; Processing the first random access message; Generating a second random access message in response to the first random access message; and Transmitting the second random access message.

26. The method according to claim 25, wherein the plurality of random access configurations includes parameters for transmitting the first random access message, and the parameters include at least one of the following: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmission power of the preamble, or power control step size.

27. The method according to claim 25, wherein the plurality of random access configurations includes at least one of the following: physical uplink shared channel (PUSCH) resource units, PUSCH waveform, PUSCH initial transmission power, frequency hopping pattern, repetition factor, modulation and coding scheme, or power control step size.

28. The method according to claim 25, wherein the preamble and the payload of the first random access message are received on the same receive beam.

29. The method according to claim 25, wherein at least one of the plurality of random access configurations includes contention-based parameters for transmitting the first random access message in a contention-based random access procedure, wherein the contention-based parameters include at least one of the following: physical random access channel (PRACH) repetition, physical uplink shared channel (PUSCH) repetition, power boost for PRACH or PUSCH, power control step size, wherein the first random access message is transmitted on a resource allocated to a set of UEs for the contention-based random access procedure.

30. An apparatus for wireless communication, comprising: a memory; and at least one processor coupled to the memory and configured to: transmit random access configuration information for a random access procedure, wherein the random access configuration information includes a plurality of random access configurations associated with a particular type of random access procedure, each of the plurality of random access configurations indicating different random access parameters configured for different random access messages in the particular type of random access procedure; receive a first random access message to initiate the particular type of random access procedure, the first random access message including a preamble and a payload, wherein the configuration of the preamble and the payload is based on one of the plurality of random access configurations; process the first random access message; generate a second random access message in response to the first random access message; and transmit the second random access message.

31. The apparatus according to claim 30, wherein the plurality of random access configurations includes parameters for transmitting the first random access message, the parameters including at least one of the following: preamble parameter design, preamble format, cyclic shift of the preamble sequence, initial transmit power of the preamble, or power control step size.

32. The apparatus according to claim 30, wherein the plurality of random access configurations includes at least one of the following: physical uplink shared channel (PUSCH) resource units, PUSCH waveform, initial transmit power of PUSCH, hopping pattern, repetition factor, modulation and coding scheme, or power control step size.

33. The apparatus according to claim 30, wherein the preamble and the payload of the first random access message are received on the same receive beam.

34. The apparatus according to claim 30, wherein at least one of the plurality of random access configurations includes contention-based parameters for transmitting the first random access message in a contention-based random access procedure, wherein the contention-based parameters include at least one of the following: physical random access channel (PRACH) repetition, physical uplink shared channel (PUSCH) repetition, power boost for PRACH or PUSCH, power control step size, wherein the first random access message is transmitted on a resource allocated to a set of UEs for the contention-based random access procedure.

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