Timing advance for random access

Abstract

Certain aspects of the present disclosure provide techniques for random access. A method for wireless communication by a user equipment (UE) includes determining a first timing advance (TA) for transmitting a random access channel (RACH) preamble. The method includes determining a second TA for transmitting the RACH preamble, the second TA being different from the first TA. The method includes transmitting the RACH preamble using the second TA. The method includes receiving a random access response (RAR) message including a timing advance command (TAC), and determining whether the RAR is intended for the UE based on the TAC, the first TA, and the second TA. The method includes transmitting a physical uplink shared channel (PUSCH) transmission based on a determination that the RAR is intended for the UE.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application serial number 17 / 816,485 filed on August 1, 2022, which is hereby incorporated by reference into this document. Background Art Technical Field

[0003] Aspects of the present disclosure relate to wireless communications and, more particularly, to techniques for random access.

[0004] Related technologies

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts or other similar types of services. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available wireless communication system resources.

[0006] Although wireless communication systems have made tremendous technical progress over the years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers. Therefore, there is a continuous desire to improve the technical performance of wireless communication systems, including, for example: improving the speed and data carrying capacity of communications, improving the efficiency of using shared communication media, reducing the power used by transmitters and receivers when performing communications, improving the reliability of wireless communications, avoiding redundant transmission and / or reception and related processing, improving the coverage area of ​​wireless communications, increasing the number and types of devices that can access wireless communication systems, increasing the ability of different types of devices to communicate with each other, increasing the number and types of wireless communication media available for use, etc. Therefore, there is a need to further improve wireless communication systems to overcome the above-mentioned technical challenges and other challenges. Summary of the invention

[0007] In random access, as part of the random access procedure, the UE sends a random access preamble. Because the number of random access preambles and random access channel (RACH) resources is limited, the UE may send conflicting random access preambles. That is, the UE can use the same RACH resources to send the same random access preamble. When the UE sends a conflicting random access preamble, the network sends a random access response message with a timing advance command, and both UEs (or no matter how many UEs send conflicting random access preambles) receive the random access response message and use the same TAC to send a physical uplink shared channel (PUSCH) payload to the network. Therefore, the PUSCH transmissions from the UE also collide at the network entity. The network entity may not be able to successfully decode one or more of the conflicting PUSCH transmissions. In this case, the UE may need to resend the PUSCH transmission and / or the random access preamble, thereby limiting the channel capacity.

[0008] According to various aspects of the present disclosure, a UE may be configured to independently determine a second timing advance based on a first timing advance and use the second timing advance to send a random access preamble. When a network entity sends a random access response message with a TAC, each UE may determine whether the random access response message is intended for itself based on, for example, the TAC, the first timing advance, and the second timing advance. For example, the UE may determine whether the random access response message is intended for itself based on the difference between the TAC and the difference between the first timing advance and the second timing advance. Subsequently, the UE may determine whether to transmit a PUSCH transmission to the network entity based on whether the random access response message is determined to be intended for the UE. Therefore, PUSCH transmission conflicts at the network entity may be avoided, thereby increasing channel capacity.

[0009] One aspect provides a method for wireless communication by a user equipment (UE). The method includes determining a first timing advance (TA) for sending a random access channel (RACH) preamble. The method includes determining a second TA for sending the RACH preamble, the second TA being different from the first TA. The method includes sending the RACH preamble using the second TA. The method includes receiving a random access response (RAR) message including a timing advance command (TAC). The method includes determining whether the RAR is intended for the UE based on the TAC, the first TA, and the second TA. The method includes sending a physical uplink shared channel (PUSCH) transmission based on determining that the RAR is intended for the UE.

[0010] On the other hand, a method for wireless communication by a network entity is provided. The method includes outputting a TA configuration for a first UE and a second UE. The method includes obtaining a first RACH preamble from the first UE using a first TA and obtaining a second RACH preamble from the second UE using a second TA. The first RACH preamble and the second RACH preamble include the same RACH sequence. The method includes outputting a RAR message including a TAC. The method includes obtaining a PUSCH transmission from the UE or the second UE based on the TAC.

[0011] Other aspects provide: an apparatus operable to, configured to, or otherwise adapted to perform the aforementioned method and those described elsewhere herein; a non-transitory computer-readable medium comprising instructions that, when executed by a processor of the apparatus, cause the apparatus to perform the aforementioned method and those described elsewhere herein; a computer program product embodied on a computer-readable storage medium, the computer-readable storage medium comprising code for performing the aforementioned method and those described elsewhere herein; and an apparatus comprising components for performing the aforementioned method and those described elsewhere herein. By way of example, an apparatus may include a processing system, a device having a processing system, or a processing system cooperating through one or more networks.

[0012] For purposes of illustration, the following description and drawings set forth certain features. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings depict certain features of the aspects described herein and should not be considered to limit the scope of the disclosure.

[0014] Figure 1 An example wireless communication network is depicted.

[0015] Figure 2 An example disaggregated base station architecture is depicted.

[0016] Figure 3 Aspects of an example base station and example user equipment are depicted.

[0017] Figure 4A , Figure 4B , Figure 4C and Figure 4D Various example aspects of data structures for a wireless communication network are described.

[0018] Figure 5 An example four-step RACH procedure is depicted.

[0019] Figure 6 An example two-step RACH procedure is depicted.

[0020] Figure 7 Depicted are example MSG2 collisions and MSG3 collisions in a four-step RACH procedure.

[0021] Figure 8 An example non-terrestrial network (NTN) is depicted.

[0022] Fig. 9 Depicted is an example process flow for timing advance in a four-step RACH procedure in a network between a network entity, a first UE, and a second UE.

[0023] Fig.10 Another example process flow for timing advance in a four-step RACH procedure in a network between a network entity, a first UE, and a second UE is depicted.

[0024] Fig.11 Depicted is an example process flow for timing advance in a two-step RACH procedure in a network between a network entity, a first UE, and a second UE.

[0025] Fig.12 Example methodologies for wireless communications by a UE are described.

[0026] Fig.13 Example methodologies for wireless communications by a network entity are described.

[0027] Fig.14 Aspects of an example communications device are depicted.

[0028] Fig.15 Aspects of an example communications device are depicted. DETAILED DESCRIPTION

[0029] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for timing advance in random access.

[0030] Introduction to wireless communication networks

[0031] The techniques and methods described herein can be used in various wireless communication networks. Although various aspects may be described herein using terms commonly associated with 3G, 4G and / or 5G wireless technologies, various aspects of the present disclosure may also be applicable to other communication systems and standards not explicitly mentioned herein.

[0032] Figure 1 An example of a wireless communication network 100 is depicted in which various aspects described herein may be implemented.

[0033] In general, the wireless communication network 100 includes various network entities (alternatively, network elements or network nodes). A network entity is typically a communication device and / or a communication function performed by a communication device (e.g., user equipment (UE), base station (BS), component of a BS, server, etc.). For example, various functions of a network and various devices associated with and interacting with the network may be considered network entities. In addition, the wireless communication network 100 includes ground aspects, such as ground-based network entities (e.g., BS 102), and non-ground aspects, such as satellites 140 and aircraft 145, which may include airborne network entities (e.g., one or more BSs) capable of communicating with other network elements (e.g., ground BSs) and user equipment.

[0034] In the depicted example, the wireless communication network 100 includes a BS 102, a UE 104, and one or more core networks (such as an evolved packet core (EPC) 160 and a 5G core (5GC) network 190) that interoperate to provide communication services over various communication links (including wired and wireless links).

[0035] Figure 1 Various example UEs 104 are depicted, which may more generally include: a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player, a camera, a game console, a tablet computer, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, an Internet of Things (IoT) device, an Always-On (AON) device, an edge processing device, or other similar devices. UE 104 may also be more generally referred to as a mobile device, a wireless device, a wireless communication device, a station, a mobile station, a subscriber station, a mobile subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a remote device, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, and others.

[0036] BS 102 wirelessly communicates with (e.g., transmits signals to or receives signals from) UE 104 via communication link 120. Communication link 120 between BS 102 and UE 104 may include uplink (UL) (also referred to as a reverse link) transmissions from UE 104 to BS 102 and / or downlink (DL) (also referred to as a forward link) transmissions from BS 102 to UE 104. In various aspects, communication link 120 may employ multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity.

[0037] BS 102 may generally include: Node B, enhanced Node B (eNB), next generation enhanced Node B (ng-eNB), next generation Node B (gNB or gNodeB), access point, base transceiver station, radio base station, radio transceiver, transceiver function, transmission and reception point, and / or other. Each of BS 102 may provide communication coverage for a corresponding geographic coverage area 110, which may sometimes be referred to as a cell, and may overlap in some cases (e.g., small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of a macro cell). For example, a BS may provide communication coverage for a macro cell (covering a relatively large geographic area), a pico cell (covering a relatively small geographic area, such as a stadium), a femto cell (relatively small geographic area (e.g., a home)), and / or other types of cells.

[0038] Although BS102 is depicted as a single communication device in various aspects, BS102 can be implemented in various configurations. For example, one or more components of the base station may be decomposed, including a central unit (CU), one or more distributed units (DU), one or more radio units (RU), a near real-time (near RT) RAN intelligent controller (RIC), or a non-real-time (non-RT) RIC, to name a few examples. In another example, various aspects of the base station may be virtualized. More generally, a base station (e.g., BS102) may include components located at a single physical location or components located at various physical locations. In an example in which the base station includes components located at various physical locations, the various components may each perform a function so that the various components together implement functionality similar to that of a base station located at a single physical location. In some aspects, a base station including components located at various physical locations may be referred to as a decomposed radio access network architecture (such as an open RAN (O-RAN) or virtualized RAN (VRAN) architecture). Figure 2 An example decomposed base station architecture is depicted and described.

[0039] Different BSs 102 within the wireless communication network 100 may also be configured to support different radio access technologies (such as 3G, 4G, and / or 5G). For example, a BS 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). A BS 102 configured for 5G (e.g., 5G NR or Next Generation RAN (NG-RAN)) may interface with the 5GC 190 via a second backhaul link 184. The BSs 102 may communicate with each other directly or indirectly (e.g., via the EPC 160 or the 5GC 190) over a third backhaul link 134 (e.g., an X2 interface), which may be wired or wireless.

[0040] The wireless communication network 100 may subdivide the electromagnetic spectrum into various categories, frequency bands, channels, or other characteristics. In some aspects, the subdivision is provided based on wavelength and frequency, where frequency may also be referred to as a carrier, subcarrier, channel, tone, or subband. For example, 3GPP currently defines frequency range 1 (FR1) as including 410 MHz-7125 MHz, which is often (interchangeably) referred to as "below 6 GHz". Similarly, 3GPP currently defines frequency range 2 (FR2) as including 24,250 MHz-52,600 MHz, which is sometimes (interchangeably) referred to as "millimeter wave" ("mmW" or "mmWave"). A base station (e.g., a mmWave base station such as BS180) configured to communicate using mmWave / near mmWave radio bands may utilize beamforming (e.g., 182) with a UE (e.g., 104) to improve path loss and range.

[0041] The communication link 120 between the BS 102 and, for example, the UE 104 may be through one or more carriers, which may have different bandwidths (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, and / or other MHz) and may be aggregated in various aspects. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​than for UL).

[0042] Communications using higher frequency bands may have higher path loss and shorter range than communications at lower frequencies. Figure 1 180) can utilize beamforming 182 with UE 104 to improve path loss and range. For example, BS 180 and UE 104 may each include multiple antennas, such as antenna elements, antenna panels and / or antenna arrays, to facilitate beamforming. In some cases, BS 180 may send beamformed signals to UE 104 in one or more transmit directions 182'. UE 104 may receive beamformed signals from BS 180 in one or more receive directions 182". UE 104 may also send beamformed signals to BS 180 in one or more transmit directions 182". BS 180 may also receive beamformed signals from UE 104 in one or more receive directions 182'. BS 180 and UE 104 may then perform beam training to determine the best receive direction and transmit direction for each of BS 180 and UE 104. It is worth noting that the transmit direction and receive direction of BS 180 may be the same or different. Similarly, the transmit direction and receive direction of UE 104 may be the same or different.

[0043] Wireless communication network 100 also includes Wi-Fi AP 150 that communicates with Wi-Fi stations (STAs) 152 via communication links 154 in, for example, the 2.4 GHz and / or 5 GHz unlicensed spectrum.

[0044] Certain UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), and / or a physical sidelink feedback channel (PSFCH).

[0045] The EPC 160 may include various functional components, including: a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and / or a packet data network (PDN) gateway 172, such as in the depicted example. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management.

[0046] Generally speaking, user Internet Protocol (IP) packets are delivered through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation and other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176, which may include, for example, the Internet, an Intranet, an IP Multimedia Subsystem (IMS), a Packet Switched (PS) streaming media service, and / or other IP services.

[0047] The BM-SC 170 may provide functionality for MBMS user service configuration and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS delivery, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and / or may be used to schedule MBMS delivery. The MBMS Gateway 168 may be used to distribute MBMS services to BSs 102 belonging to a multicast broadcast single frequency network (MBSFN) area broadcasting a specific service, and / or may be responsible for session management (start / stop) and for collecting eMBMS related charging information.

[0048] 5GC 190 may include various functional components, including: access and mobility management function (AMF) 192, other AMFs 193, session management function (SMF) 194, and user plane function (UPF) 195. AMF 192 may communicate with unified data management (UDM) 196.

[0049] AMF 192 is a control node that handles signaling between UE 104 and 5GC 190. AMF 192 provides, for example, Quality of Service (QoS) flow and session management.

[0050] Internet Protocol (IP) packets are delivered through UPF 195, which is connected to IP Services 197 and provides IP address allocation for UEs and other functions for 5GC 190. IP Services 197 may include, for example, the Internet, Intranet, IMS, PS streaming services, and / or other IP services.

[0051] In various aspects, a network entity or network node may be implemented as a converged base station, a decomposed base station, a component of a base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, to name a few examples.

[0052] Figure 2 An example disaggregated base station 200 architecture is depicted. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that may communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 225 via an E2 link, or a non-real-time (non-RT) RIC 215 associated with a service management and orchestration (SMO) framework 205, or both. The CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DU 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RU 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served simultaneously by multiple RUs 240.

[0053] Each of the units (e.g., CU 210, DU 230, RU 240, and near-RT RIC 225, non-RT RIC 215, and SMO framework 205) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interface of the unit may be configured to communicate with one or more of the other units via a transmission medium. For example, the units may include a wired interface configured to receive or send signals to one or more of the other units via a wired transmission medium. Additionally or alternatively, the unit may include a wireless interface that may include a receiver, transmitter, or transceiver (such as a radio frequency (RF) transceiver) configured to receive signals on a wireless transmission medium or send signals to one or more of the other units, or both.

[0054] In some aspects, CU 210 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by CU 210. CU210 may be configured to handle user plane functionality (e.g., central unit-user plane (CU-UP)), control plane functionality (e.g., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 210 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 210 may be implemented to communicate with DU 230 for network control and signaling.

[0055] DU 230 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 240. In some aspects, DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) at least in part according to a functional split such as those defined by the 3rd Generation Partnership Project (3GPP). In some aspects, DU 230 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 230 or with control functions hosted by CU 210.

[0056] The lower layer functionality may be implemented by one or more RUs 240. In some deployments, the RU 240 controlled by the DU 230 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on functional splitting (such as lower layer functional splitting). In such an architecture, the RU 240 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some specific implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU 240 may be controlled by the corresponding DU 230. In some scenarios, this configuration may enable the DU 230 and CU 210 to be implemented in a cloud-based RAN architecture (such as a vRAN architecture).

[0057] The SMO framework 205 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 210, DU 230, RU 240, and near-RT RIC 225. In some specific implementations, the SMO framework 205 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 211) via the O1 interface. Additionally, in some specific implementations, the SMO framework 205 may communicate directly with one or more RUs 240 via the O1 interface. The SMO framework 205 may also include a non-RT RIC 215 configured to support the functionality of the SMO framework 205 .

[0058] The non-RT RIC 215 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 225. The non-RT RIC 215 may be coupled to or in communication with the near-RT RIC 225 (such as via an A1 interface). The near-RT RIC 225 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 210, one or more DUs 230, or both, and the O-eNB with the near-RT RIC 225.

[0059] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 225, the non-RT RIC 215 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 225 and may be received from a non-network data source or from a network function at the SMO framework 205 or the non-RT RIC 215. In some examples, the non-RT RIC 215 or the near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 215 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 205 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0060] Figure 3 Aspects of an example BS 102 and UE 104 are depicted.

[0061] In general, BS 102 includes various processors (e.g., 320, 330, 338, and 340), antennas 334a-334t (collectively 334), transceivers 332a-332t (collectively 332) including modulators and demodulators, and other aspects that enable wireless transmission of data (e.g., data source 312) and wireless reception of data (e.g., data sink 339). For example, BS 102 can transmit and receive data between BS 102 and UE 104. BS 102 includes a controller / processor 340 that can be configured to implement various functions described herein related to wireless communication.

[0062] In general, the UE 104 includes various processors (e.g., 358, 364, 366, and 380), antennas 352a-352r (collectively 352), transceivers 354a-354r (collectively 354) including modulators and demodulators, and other aspects that enable wireless transmission of data (e.g., retrieved from a data source 362) and wireless reception of data (e.g., provided to a data sink 360). The UE 104 includes a controller / processor 380 that can be configured to implement various functions described herein related to wireless communications.

[0063] Regarding example downlink transmissions, BS 102 includes a transmit processor 320 that can receive data from a data source 312 and control information from a controller / processor 340. The control information can be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical HARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), and / or others. In some examples, the data can be for a physical downlink shared channel (PDSCH).

[0064] The transmit processor 320 may process (e.g., encode and symbol map) data and control information to obtain data symbols and control symbols, respectively. The transmit processor 320 may also generate reference symbols (such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH demodulation reference signal (DMRS), and a channel state information reference signal (CSI-RS)).

[0065] The transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., pre-decoding) on ​​data symbols, control symbols, and / or reference symbols, where applicable, and may provide an output symbol stream to a modulator (MOD) in a transceiver 332a-332t. Each modulator in the transceiver 332a-332t may process a corresponding output symbol stream to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from the modulators in the transceivers 332a-332t may be transmitted via antennas 334a-334t, respectively.

[0066] To receive downlink transmissions, UE 104 includes antennas 352a-352r that can receive downlink signals from BS 102 and can provide received signals to demodulators (DEMODs) in transceivers 354a-354r, respectively. Each demodulator in transceivers 354a-354r can condition (e.g., filter, amplify, downconvert, and digitize) a corresponding received signal to obtain input samples. Each demodulator can further process the input samples to obtain received symbols.

[0067] A MIMO detector 356 may obtain received symbols from all demodulators in transceivers 354a-354r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 104 to a data sink 360, and provide decoded control information to a controller / processor 380.

[0068] With respect to example uplink transmissions, the UE 104 also includes a transmit processor 364 that may receive and process data from a data source 362 (e.g., for a PUSCH) and control information from a controller / processor 380 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 364 may also generate reference symbols for reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 364 may be pre-decoded by a TX MIMO processor 366, if applicable, further processed by a modulator in the transceivers 354a-354r (e.g., for SC-FDM), and transmitted to the BS 102.

[0069] At BS 102, uplink signals from UE 104 may be received by antennas 334 a-334 t, processed by demodulators in transceivers 332 a-332 t, detected by MIMO detector 336 if applicable, and further processed by receive processor 338 to obtain decoded data and control information transmitted by UE 104. Receive processor 338 may provide decoded data to data sink 339 and decoded control information to controller / processor 340.

[0070] Memories 342 and 382 may store data and program codes for BS 102 and UE 104, respectively.

[0071] Scheduler 344 may schedule UEs for data transmission on the downlink and / or uplink.

[0072] In various aspects, BS 102 may be described as sending and receiving various types of data associated with the methods described herein. In these contexts, "sending" may refer to various mechanisms for outputting data, such as outputting data from a data source 312, a scheduler 344, a memory 342, a transmit processor 320, a controller / processor 340, a TX MIMO processor 330, a transceiver 332a-332t, an antenna 334a-334t, and / or other aspects described herein. Similarly, "receiving" may refer to various mechanisms for obtaining data, such as obtaining data from an antenna 334a-334t, a transceiver 332a-332t, a RX MIMO detector 336, a controller / processor 340, a receive processor 338, a scheduler 344, a memory 342, and / or other aspects described herein.

[0073] In various aspects, the UE 104 may also be described as sending and receiving various types of data associated with the methods described herein. In these contexts, "sending" may refer to various mechanisms for outputting data, such as outputting data from a data source 362, a memory 382, ​​a transmit processor 364, a controller / processor 380, a TX MIMO processor 366, a transceiver 354a-354t, an antenna 352a-352t, and / or other aspects described herein. Similarly, "receiving" may refer to various mechanisms for obtaining data, such as obtaining data from an antenna 352a-352t, a transceiver 354a-354t, a RX MIMO detector 356, a controller / processor 380, a receive processor 358, a memory 382, ​​and / or other aspects described herein.

[0074] In some aspects, the processor may be configured to perform various operations (such as those associated with the methods described herein) and send (output) data to or receive (obtain) data from another interface configured to send or receive data, respectively.

[0075] Figure 4A , Figure 4B , Figure 4C and Figure 4D Describes a method for use in a wireless communication network such as Figure 1 Various aspects of the data structure of the wireless communication network 100).

[0076] Specifically, Figure 4A is a diagram 400 illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure, Figure 4B is a diagram 430 illustrating an example of a DL channel within a 5G subframe, Figure 4C is a diagram 450 illustrating an example of a second subframe within a 5G frame structure, and Figure 4D FIG480 is a diagram illustrating an example of UL channels within a 5G subframe.

[0077] Wireless communication networks can utilize Orthogonal Frequency Division Multiplexing (OFDM) with a Cyclic Prefix (CP) on both the uplink and downlink. Such systems can also support half-duplex operation using Time Division Duplex (TDD). OFDM and Single Carrier Frequency Division Multiplexing (SC-FDM) can be used to maximize the system bandwidth (e.g., Figure 4B and Figure 4D The RF (depicted) is divided into multiple orthogonal subcarriers. Each subcarrier can be modulated with data. Modulation symbols can be transmitted in the frequency domain using OFDM and / or in the time domain using SC-FDM.

[0078] The wireless communication frame structure may be frequency division duplex (FDD), where for a particular set of subcarriers, subframes within the set of subcarriers are dedicated to either DL or UL. The wireless communication frame structure may also be time division duplex (TDD), where for a particular set of subcarriers, subframes within the set of subcarriers are dedicated to both DL and UL.

[0079] exist Figure 4A and Figure 4C In the wireless communication frame structure, TDD is used, where D is DL, U is UL, and X is used flexibly between DL / UL. The UE can be configured with a time slot format (dynamically configured by DL control information (DCI) or semi-statically / statically configured by radio resource control (RRC) signaling) through the received time slot format indicator (SFI). In the depicted example, the 10ms frame is divided into 10 equally sized 1ms subframes. Each subframe may include one or more time slots. In some examples, each time slot may include 7 or 14 symbols, depending on the time slot format. The subframe may also include a micro-time slot, which generally has fewer symbols than the entire time slot. Other wireless communication technologies may have different frame structures and / or different channels.

[0080] In certain aspects, the number of slots within a subframe is based on the slot configuration and parameter set. For example, for slot configuration 0, different parameter sets (μ) 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots per subframe, respectively. For slot configuration 1, different parameter sets 0 to 2 allow for 2, 4, and 8 slots per subframe, respectively. Thus, for slot configuration 0 and parameter set μ, there are 14 symbols / slot and 2μ slots / subframe. The subcarrier spacing and symbol length / duration are a function of the parameter set. The subcarrier spacing may be equal to 2 μ × 15kHz, where μ is parameter set 0 to 5. Thus, parameter set μ=0 has a subcarrier spacing of 15kHz, and parameter set μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figure 4A , Figure 4B , Figure 4C and Figure 4D An example is provided for slot configuration 0 with 14 symbols per slot and parameter set μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

[0081] like Figure 4A , Figure 4B , Figure 4C and Figure 4DAs depicted, a resource grid may be used to represent a frame structure. Each slot includes a resource block (RB) (also referred to as a physical RB (PRB)) extending, for example, over 12 consecutive subcarriers. The resource grid is divided into a plurality of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0082] like Figure 4A As illustrated, some of the REs carry data for the UE (eg, Figure 1 and Figure 3 The RS may include a demodulation RS (DMRS) and / or a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and / or a phase tracking RS (PT-RS).

[0083] Figure 4B Examples of various DL channels within a subframe of a frame are illustrated.The Physical Downlink Control Channel (PDCCH) carries DCI within one or more Control Channel Elements (CCEs), each CCE comprising, for example, nine RE Groups (REGs), each REG comprising, for example, four consecutive REs in an OFDM symbol.

[0084] The primary synchronization signal (PSS) may be in symbol 2 of a particular subframe of a frame. The PSS is transmitted by a UE (e.g., Figure 1 and Figure 3 104) is used to determine subframe / symbol timing and physical layer identity.

[0085] The Secondary Synchronization Signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing.

[0086] Based on the physical layer identifier and the physical layer cell identifier group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DMRS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information (such as system information blocks (SIBs)) that is not sent via the PBCH, and / or paging messages.

[0087] As in Figure 4CAs illustrated, some REs carry DMRS for channel estimation at the base station (indicated as R for a particular configuration, but other DMRS configurations are possible). The UE may send a DMRS for PUCCH and a DMRS for PUSCH. The PUSCH DMRS may be sent, for example, in the first one or two symbols of the PUSCH. The PUCCH DMRS may be sent in different configurations depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used. UE 104 may send a sounding reference signal (SRS). The SRS may be sent, for example, in the last symbol of a subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the teeth of the comb. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

[0088] Figure 4D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at a position as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may be used to carry, among other things, buffer status reports (BSRs), power headroom reports (PHRs), and / or UCI.

[0089] Example RACH Procedure

[0090] Aspects of the present disclosure relate to timing advance for random access. The random access channel is so named because it refers to a channel that can be used by multiple UEs (e.g., such as Figure 1 and Figure 3 A wireless channel (medium) shared by UEs 104 of a network and used by these UEs to (randomly) access the network for communication. For example, RACH can be used for call setup and access to the network for data transmission. In some cases, RACH can be used for initial access to the network when the UE switches from radio resource control (RRC) connection idle mode to active mode, or when switching in RRC connection mode. In addition, RACH can be used for downlink (DL) and / or uplink (UL) data arrival when the UE is in RRC idle or RRC inactive mode, and when reestablishing a connection with the network.

[0091] Figure 5 5 is a diagram of a process flow 500 (or "sequence" or "call flow") illustrating an example four-step RACH procedure in accordance with certain aspects of the present disclosure. A RACH may be sent from a UE 504 to a network entity 502 (such as a Figure 1 and Figure 3The BS 102 of FIG. 1 transmits a first message (MSG1). In this case, MSG1 may include only a RACH preamble. The RACH preamble may include a cyclic prefix (CP), a sequence (eg, a Zadoff-Chu sequence), and a guard period.

[0092] The network entity 502 may respond with a RAR message (MSG2) that may include an identifier (ID) of the RACH preamble, a timing advance command (TAC), an uplink grant, a temporary cell radio network temporary identifier (TC-RNTI), and a fallback indicator.

[0093] In response to MSG2, MSG3 is sent on the PUSCH from the UE 504 to the network entity 502. MSG3 may include one or more of an RRC connection request, a tracking area update (TAU) request, a system information request, a positioning fix or positioning signal request, a UE-ID (such as C-RNTI), a medium access control control element (MAC CE), or a scheduling request.

[0094] The network entity 502 then responds with MSG4, which may include a contention resolution message and / or a DCI.

[0095] In some cases, to speed up access, a two-step RACH procedure may be supported. As the name implies, the two-step RACH procedure effectively "collapses" the four messages of the four-step RACH procedure into two messages.

[0096] Figure 6 6 is a process flow 600 illustrating an example two-step RACH procedure in accordance with certain aspects of the present disclosure. A first enhanced message (MSGA) may be transmitted from a UE 604 to a network entity 602. The MSGA includes some or all of the information from MSG1 and MSG3 in a four-step RACH procedure, effectively combining MSG1 and MSG3. For example, the MSGA may include MSG1 and MSG3 multiplexed together, such as using one of time division multiplexing or frequency division multiplexing. The MSGA may include a RACH preamble and a payload for random access. For example, the MSGA payload may include a UE-ID, a buffer status report (BSR), an RRC connection request, a TAU request, a system information request, a location lock or positioning signal request, and / or a scheduling request.

[0097] The network entity 602 may respond with a RAR message (MSGB), which may effectively combine the above-mentioned MSG2 and MSG4. For example, the MSGB may include an ID of a RACH preamble, a TAC, a backoff indicator, a contention resolution message, an UL / DL grant, and a transmit power control (TPC) command.

[0098] Aspects related to timing advance in random access

[0099] In some cases, RACH preambles from multiple UEs may "collide". Figure 7 7 is a process flow diagram illustrating an example of a RACH preamble collision in a four-step RACH procedure. As shown, at 708 and 710, both UE 704 and UE 706 transmit RACH preambles to network entity 702, respectively. The RACH preambles transmitted by UE 704 and UE 706 may be the same. That is, UE 704 and UE 706 may generate RACH preambles having the same sequence and send the RACH preambles to network entity 702 in the same RACH resource and RACH opportunity.

[0100] At 712, in response to receiving MSG1, network entity 702 transmits MSG2 RAR with resource allocation, MCS, and TAC for MSG3. Because the RACH preamble is the same, UE 704 and UE 706 receive the same MSG2.

[0101] At 714 and 716, in response to receiving the same MSG2, UE 704 and UE 706 both transmit MSG3 to network entity 702 in the same resources, respectively. Therefore, the MSG3 transmissions from UE 704 and UE 706 may collide at network entity 702, resulting in a reduced signal-to-interference-and-noise ratio (SINR), for example, an SINR below 0 dB. The low SINR may cause network entity 702 to fail to successfully receive and decode one or both of the MSG3 transmissions from the one or both UEs, and thus network entity 702 may fail to send a response (e.g., MSG4 and / or DCI) confirming MSG3 reception to the one or both UEs. When network entity 702 fails to successfully receive the MSG3 transmission, the UE may need to retransmit MSG3 or may need to transmit both MSG1 and MSG3. Therefore, system capacity may be limited due to collisions occurring during random access.

[0102] It should be noted that although Figure 7 Two UEs sending colliding RACH preambles are illustrated, but any number of UEs may send colliding RACH preambles. Non-terrestrial networks (NTNs) are a particular example of a scenario where the random access collision rate may be particularly high.

[0103] As discussed above, the wireless communication network 100 may include terrestrial aspects, such as ground-based network entities (e.g., BS 102), and non-terrestrial aspects, such as satellite 140 and aircraft 145, which non-terrestrial aspects may include airborne network entities (e.g., at least a portion of one or more BSs) capable of communicating with other network elements (e.g., terrestrial BSs and / or non-terrestrial BSs) and UEs.

[0104] Figure 8 An example of a wireless communication network 800 including a UE, an NTN entity, and an NTN gateway is illustrated. In some examples, the wireless communication network 800 may implement aspects of the wireless communication network 100. For example, the wireless communication network 800 may include a BS 102, a UE 104, and a satellite 140. In the case of a terrestrial network, the BS 102 may serve a coverage area (or cell) 110a, while in the case of an NTN, the satellite 140 may serve a coverage area 110b. Some NTNs may employ airborne platforms (e.g., drones or balloons) and / or spaceborne platforms (e.g., satellites). The satellite 140 may communicate with a terrestrial gateway (e.g., a satellite dish) via a feeder link. The BS 102 may be co-located with the gateway, deployed behind the gateway, and / or deployed on the satellite 140.

[0105] As part of wireless communications in the NTN, the satellite 140 may communicate with the BS 102 and the UE 104. The UE 104 may communicate with the BS 102 via a communication link 814. The satellite 140 may be a serving cell for the UE 104 via a communication link 816, referred to as a serving link. In certain aspects, the satellite 140 may act as a repeater (or remote radio head) for the BS 102 and the UE 104. For example, the BS 102 may communicate with the satellite 140 via a communication link 818, referred to as a feeder link, and the non-terrestrial network entities may relay signaling between the BS 102 and the UE 104 via the communication links 816 and 818.

[0106] NTN can serve UEs in rural areas. Satellite 140 (or other NTN entity) can serve very large coverage area 110b. In some cases, UEs in NTN coverage area 110b use small messages (such as using NB Internet of Things (IoT)) to communicate. In some cases, these UEs can transmit small messages in MSG3 / MSGB during random access, which is called early data transmission (EDT) or small data transmission (SDT). Because NTN coverage area 110b is large, many UEs can be served within NTN coverage area 110b. Therefore, the possibility of RACH preamble collision and missing EDT is higher.

[0107] Therefore, a random access procedure technique that reduces the collision rate is needed.

[0108] Example Operations of Entities in a Communication Network

[0109] Aspects of the present disclosure provide techniques, apparatus, and computer-readable media for random access with collision reduction.

[0110] Fig. 9 A process flow diagram 900 illustrating communications in a network between an example network entity 902 and UEs 904 and 906. In some aspects, the network entity 902 may be a Figure 1 and Figure 3 BS102 as depicted and described or for Figure 2 An example of a decomposed base station is depicted and described. Similarly, UE 904 and UE 906 may be for Figure 1 and Figure 3 The depicted and described example of UE 104. However, in other aspects, UE 904 and UE 906 may be another type of wireless communication device, and network entity 902 may be another type of network entity or network node, such as those described herein.

[0111] As shown, the network entity 902 may configure a timing advance configuration for the UE 904 and the UE 906. In some aspects, the TA configuration configures a range of timing advances, a range of TA offsets (σ) and / or their distribution, TA values ​​and / or one or more thresholds. The TA configuration is discussed in more detail below for 916, 918, 926, and 928 in the process flow 900. In some examples, the network entity 902 determines the range of TA offsets to be configured and / or their distribution based on the ability of the network entity 902 to decode the RACH preamble. In some examples, the TA configuration configures a range of a second difference between the first TA and the second TA or an offset range according to a uniform distribution. In some examples, the TA configuration may be broadcast (e.g., in a SIB) to the UE or provided to the UE in RRC signaling.

[0112] Despite Fig. 9 908 and 910 are shown at the same time, but it should be understood that the network entity 902 can configure the UE 904 and the UE 906 at different times.

[0113] In some aspects, the TA configuration or a portion of the TA configuration may be pre-configured, such as hard-coded at the UE 904 and UE 906 and / or specified in a wireless standard (eg, a 3GPP technical standard).

[0114] At 912, UE 904 determines a first TA, and at 914, UE 906 determines a first TA. UE 904 and UE 906 may determine the first TA according to known TA determination techniques specified in 3GPP wireless standards (e.g., in TS 38.211 and / or TS 38.213). UE 904 and UE 906 may determine the first TA based on the location of the UE, ephemeris information associated with an NTN entity (in the NTN network), the location of the network entity 902, a received TA command, and / or one or more common TA parameters. UE 904 and UE 906 may determine the first TA to compensate for a round trip time (RTT) between the UE and an uplink synchronization reference point. The uplink synchronization reference point may be determined by the network.

[0115] At 916, UE 904 determines a second TA, and at 918, UE 906 determines a second TA. UE 904 and UE 906 may determine their respective second TAs based on a configured or preconfigured TA configuration. UE 904 and UE 906 may determine the second TA independently. That is, UE 904 and UE 906 may determine different second TAs.

[0116] In some examples, both UE 904 and UE 906 randomly select a second TA from a configured or preconfigured TA range. In some examples, both UE 904 and UE 906 randomly select an offset (σ) value from a configured or preconfigured offset value range. UE 904 and UE 906 may each apply the selected offset value to the determined first TA to determine the corresponding second TA. The second TA has a second difference σ for the first TA (e.g., second TA=first TA-σ). Since the UE applies the first TA so that the timing of its uplink transmission arriving at the uplink synchronization reference point can be aligned with the uplink time slot timing at the uplink synchronization reference point, σ effectively contributes to the offset between the timing of the UE's uplink transmission arriving at the uplink synchronization reference point and the uplink time slot timing at the uplink synchronization reference point. Therefore, if two UEs apply different σ values ​​to send their uplinks in the same uplink time slot, the signals will arrive at the network entity at different times.

[0117] In some examples, the second TA is equal to or less than the first TA. The second TA being less than the first TA can ensure that the TAC provided by the network entity 902 in the RAR (eg, in MSG2 discussed in more detail below with respect to 924 in process flow 900) is a single extreme value.

[0118] At 920, UE 904 transmits a RACH preamble transmission (e.g., MSG1) to network entity 902 using the second TA determined by UE 904 at 916. At 922, UE 906 transmits a RACH preamble transmission (e.g., MSG1) to network entity 902 using the second TA determined by UE 906 at 918. The RACH preambles transmitted by UE 904 and UE 906 to network entity 902 may collide. That is, as discussed above, the RACH preamble transmitted by UE 904 and the RACH preamble transmitted by UE 906 may be the same, have the same RACH preamble sequence and be in the same RACH opportunity. However, due to the different second TAs determined by UE 904 and UE 906, the RACH preambles arrive at the network entity at different times. More specifically, due to the different σ values ​​determined by UE 904 and UE 906, the RACH preambles arrive at the network entity at different times. Therefore, as discussed in more detail below, using the second TA may enable MSG3 collision avoidance even when the RACH preambles are the same.

[0119] After receiving multiple RACH preamble copies with time differences, the network entity 902 determines the TAC based on one of the RACH preambles. At 924, the network entity 902 sends MSG2 with the TAC to UE 904 and UE 906. MSG2 may also include the above-mentioned Figure 5 and Figure 7 Any information discussed in MSG2.

[0120] Both UE 904 and UE 906 may receive MSG2 transmission. After receiving MSG2 with TAC, UE 904 may determine whether MSG2 is intended for UE 904 based on the TAC received at 924, the first TA determined at 912, and the second TA determined at 916. For example, UE 904 may determine whether MSG2 is intended for UE 904 based on a first difference (e.g., TAC-σ, where σ=first TA-second TA) between the TA indicated by the received TAC and the second difference between the first TA and the second TA. In some examples, when the first difference is less than a threshold, UE 904 determines that MSG2 is intended for UE 904, for example, as shown at 926. Similarly, UE 906 may determine whether MSG2 is intended for UE 906 based on the TAC received at 924, the first TA determined at 914, and the second TA determined at 918. In some examples, when the first difference is equal to or greater than a threshold, UE 906 determines that MSG2 is not intended for UE 906, for example, as shown at 928.

[0121] In some examples, the threshold is configured or preconfigured. For example, the threshold can be configured using the TA configuration at 908 and 910.

[0122] In some examples, the threshold value may depend on the accuracy of the first TA determined at 912 and 914. For example, if the orbit prediction model or the global navigation satellite system (GNSS) model used by UE 904 and / or UE 906 has a low accuracy, the timing advance determined by the UE (e.g., the first TA based on the location information of the UE and the satellite) will be less accurate. For example, for low-cost UEs or low-complexity UEs, the model used by the UE may be less accurate. In this case, because the time difference between the arrival of the RACH preamble at the network entity 902 and the uplink timeslot timing at the network entity is within a larger range due to the inaccuracy of the TA, the TAC in MSG2 from the network entity 902 may contain TA values ​​within a statistically larger range. Therefore, when the TA determined by the UE is less accurate, a larger threshold value may be used. In this case, using a larger threshold can reduce the probability of false detection, where MSG2 is intended for the UE, but because the first difference between the TA indicated by the received TAC and the second difference between the first TA and the second TA is equal to or greater than the threshold (TAC-σ≥threshold), the UE believes that MSG2 is not intended for the UE.

[0123] In some examples, UE 904, UE 906, or network entity 902 may adjust the threshold based on the number of random access attempts. For example, if UE 904 or UE 906 performs MSG1 transmission up to a threshold (e.g., a configured or preconfigured threshold) number of times, and the corresponding MSG2 transmission is determined to be not intended for the UE, the UE may adjust the threshold. The adjusted threshold may be a larger threshold. In some examples, the UE adjusts the threshold by a configured or preconfigured offset from the current threshold.

[0124] When, at 926, UE 904 determines that MSG2 is intended for UE 904, then at 930, UE 904 sends MSG3, as shown. MSG3 may include the above-mentioned Figure 5 and Figure 7 On the other hand, when at 928, UE 906 determines that MSG2 is not intended for UE 906, then UE 906 sends MSG3, such as Fig. 9 As shown. Therefore, even in the case where UE 904 and UE 906 send conflicting RACH preamble code transmissions to network entity 902, UE 904 and UE 906 do not send conflicting MSG3 transmissions to network entity 902. Therefore, for example, Figure 7Compared with the illustrated random access procedure, the present random access procedure may have a reduced collision rate. The reduced collision rate may enable an increase in system capacity, for example, by increasing the number of EDT / SDT transmissions during the random access procedure.

[0125] At 932, network entity 902 sends MSG4 to UE 904. MSG4 may include the above Figure 5 Any information discussed in MSG4 in, including contention resolution. In some examples, additionally or alternatively, the network entity 902 may send DCI to the UE 904.

[0126] According to certain aspects, when network entity 902 detects the same RACH preamble but with a time difference (e.g., due to a different second TA and / or σ value for the RACH preamble, as described herein), network entity 902 may send multiple MSG2 transmissions, such as Fig.10 As illustrated by the process flow 1000 in FIG. As shown, based on receiving two identical but time-differenced RACH preambles at 920 and 922, the network entity 902 sends a first MSG2 at 924 and also sends a second MSG2 at 1025. The first MSG2 at 924 and the second MSG2 at 1025 include different TACs (e.g., corresponding to two different timing offsets detected by the network entity 902 relative to the received RACH preamble), and may also include different UL grants and different temporary cell radio network temporary identifiers (TC-RNTIs). The first MSG2 at 924 and the second MSG2 at 1025 may include the same random access RNTI (RA-RNTI) and / or the same RA preamble identifier (RAPID).

[0127] UEs 904 and 906 monitor and receive the first MSG2 transmission at 924 and the second MSG2 transmission at 1015 and determine whether these MSG2 transmissions are intended for the UE, as described above for Fig. 9 As described.

[0128] As shown, at 926, UE 904 determines that the first MSG2 RAR is intended for UE 904. UE 904 determines (not shown) that the second MSG2 RAR is not intended for UE 904. Therefore, at 930, UE 904 sends a first MSG3 PUSCH using information indicated in the first MSG2 RAR (e.g., TAC and uplink grant), and at 921, monitors a first MSG4 from a network entity based on information indicated in the first MSG2 RAR (e.g., TC-RNTI in the first MSG2 RAR).

[0129] As shown, at 1027, the UE 906 determines that the second MSG2 RAR is intended for the UE 906. The UE 906 determines (not shown) that the first MSG2 RAR is not intended for the UE 906. Therefore, at 1031, the UE 906 sends a second MSG3 PUSCH using the information indicated in the second MSG2 RAR (e.g., TAC and uplink grant), and at 1031, monitors a second MSG4 from the network entity based on the information indicated in the second MSG2 RAR (e.g., TC-RNTI in the second MSG2 RAR).

[0130] Therefore, the MSG3 transmissions by UE 904 and UE 906 at 930 and 1031, respectively, do not collide at network entity 902 due to the different uplink grants in the two MSG2 transmissions.

[0131] According to certain aspects, even after the UE receives the RA-RNTI associated with the transmitted RACH preamble in MSG2 and MSG1 for the preamble during the response window, UE 904 and UE 906 still monitor the entire response window. The response window can be configured (e.g., via RRC parameter ra-ResponseWindow) or preconfigured.

[0132] According to certain aspects, if network entity 902 does not receive MSG3, network entity 902 may or may not schedule MSG3 to be retransmitted in response to a resource allocation included in MSG2 for one of the UEs.

[0133] It should be understood that although Figures 9 and 10 A four-step RACH procedure is described, but aspects described herein are also applicable to a two-step RACH procedure, such as Fig.11 As shown in the illustrated process flow 1100. For the case of a two-step RACH procedure, steps 908, 910, 912, 914, 916, and 918 may be performed as described above for Fig.10 At 1120 and 1122, UE 904 and UE 906 use the second TA determined at 916 and 918, respectively, to send a RACH preamble in the MSGA transmission. Figure 6 Step 606 in FIG. 1 describes the MSGA transmission. At 1124 and 1125, the network entity 902 transmits the first fallback RAR and the second fallback RAR in the first MSGB transmission and the second MSGB transmission, respectively. Figure 6Step 608 in describes the MSGB transmission. The fallback RAR may be transmitted in a medium access control (MAC) sub-protocol data unit (PDU). The first fallback RAR and the second fallback RAR carry different TACs and may carry different UL grants and / or different C-RNTIs or different TC-RNTIs.

[0134] According to certain aspects, even after the UE receives the RA-RNTI associated with the transmitted RACH preamble in the MSGB and MSGA for the preamble during the response window, UE 904 and UE 906 still monitor the entire response window for receiving the MSGB. The response window can be configured (e.g., via RRC parameter msgB-ResponseWindow) or preconfigured.

[0135] At 926 and 1027, UE 904 and UE 906, respectively, determine whether the first RAR and the second RAR are intended for the UE, as described above for Fig.10 As described. In MSGB, the fallback RAR instructs the UE to fall back to the four-step RACH procedure for sending MSG3 and monitoring MSG4. Therefore, when the UE determines that the fallback RAR is intended for the UE, the UE falls back to the four-step RACH and sends MSG3 (as shown at 930 and 1031, respectively) and monitors MSG4 at 932 and 1033, respectively.

[0136] It should be understood that although Figures 9 to 11 Two UEs (904 and 906) transmitting colliding RACH preambles are illustrated, but aspects described herein may be applicable to any number of UEs.

[0137] Example Operation of User Equipment

[0138] Fig.12 The method for use by a UE such as Figure 1 and Figure 3 Method 1200 for performing wireless communications with UE 104).

[0139] Method 1200 begins at 1202 by determining a first TA for sending a RACH preamble.

[0140] The method 1200 then proceeds to step 1204: determining a second TA for sending the RACH preamble, the second TA being different from the first TA.

[0141] The method 1200 then proceeds to step 1206: using the second TA to send the RACH preamble.

[0142] The method 1200 then proceeds to step 1208: receiving a RAR message including a TAC.

[0143] The method 1200 then proceeds to step 1210: determining whether the RAR is intended for the UE based on the TAC, the first TA, and the second TA.

[0144] The method 1200 then proceeds to step 1212: sending a PUSCH transmission based on determining that the RAR is intended for the UE.

[0145] In one aspect, method 1200 further includes refraining from transmitting the PUSCH based on determining that the RAR is not intended for the UE.

[0146] In one aspect, determining the second TA at 1204 includes receiving a configuration or preconfiguration for determining the second TA and determining the second TA based on the configuration or preconfiguration. In one aspect, the configuration for determining the second TA includes an offset range, and determining the second TA based on the configuration includes selecting an offset from the offset range and applying the offset to the first TA to determine the second TA. In one aspect, selecting the offset from the offset range includes randomly selecting an offset from the offset range.

[0147] In one aspect, the second TA is equal to or less than the first TA.

[0148] In one aspect, determining at 1210 whether the RAR is intended for the UE includes determining that the RAR is intended for the UE when the first difference is less than a threshold. The first difference is a difference between the TAC and the second difference. The second difference is a difference between the first TA and the second TA. Determining at 1210 whether the RAR is intended for the UE includes determining that the RAR is not intended for the UE when the first difference is equal to or greater than a threshold.

[0149] In one aspect, method 1200 also includes receiving signaling configuring the threshold at the UE.

[0150] In one aspect, the method 1200 further includes determining a threshold based on a characteristic associated with the first TA.

[0151] In one aspect, method 1200 further comprises adjusting the threshold based on the number of random access attempts.

[0152] In one aspect, adjusting the threshold based on the number of random access attempts includes adjusting the threshold after determining that a configured threshold number of RARs are not intended for the UE.

[0153] In one aspect, the method 1200 further includes receiving a second RAR after sending the RACH preamble and before sending the PUSCH, the second RAR including the second TAC. In one aspect, the method 1200 further includes determining that the second RAR is not intended for the UE based on a third difference between the second TAC and a second difference between the first TA and the second TA.

[0154] In one aspect, the RAR includes a RA-RNTI, a RAPID, or both, and the second RAR includes the same RA-RNTI, the same RAPID, or both.

[0155] In one aspect, sending the RACH preamble at 1206 includes sending a RACH message and a PUSCH. In one aspect, receiving the RAR at 1208 includes receiving a fallback RAR in a RACH message.

[0156] In one aspect, the method 1200 further includes monitoring an entire configured RAR window in which one or more RARs are received.

[0157] In one aspect, determining the first TA includes determining the first TA based on a location of the UE, ephemeris information, one or more configured common TA parameters, or a combination thereof.

[0158] In one aspect, the RACH preamble transmission and the PUSCH transmission include NB-IoT EDT or SDT.

[0159] In one aspect, the UE utilizes the NTN to perform RACH procedures.

[0160] In one aspect, method 1200 or any aspect related thereto may be performed by an apparatus such as Fig.14 The method 1200 is performed by a communication device 1400 that includes various components operable to, configured to, or adapted to perform the method 1200. The communication device 1400 is described in more detail below.

[0161] It should be noted that Fig.12 This is merely one example of a method, and other methods including fewer, additional, or alternative steps are also possible consistent with the present disclosure.

[0162] Example Operations of Network Entities

[0163] Fig.13 A method for transmitting data to a network entity such as Figure 1 and Figure 3 BS102 or for Figure 2 A method 1300 for performing wireless communications using a decomposed base station) as discussed above.

[0164] Method 1300 begins at 1302 by outputting timing advance (TA) configurations for a first UE and a second UE.

[0165] The method 1300 then proceeds to step 1304: obtaining a first RACH preamble from the first UE using a first TA and obtaining a second RACH preamble from the second UE using a second TA. The first RACH preamble and the second RACH preamble include the same RACH sequence.

[0166] The method 1300 then proceeds to step 1306: outputting a RAR message including the TAC.

[0167] The method 1300 then proceeds to step 1308: obtaining a PUSCH transmission from the first UE or the second UE based on the TAC.

[0168] In one aspect, the first RACH preamble and the second RACH preamble are acquired at different times.

[0169] In one aspect, the TA configuration includes an offset range or a range of TA values.

[0170] In one aspect, method 1300 further includes determining an offset range or a TA value range based on a capability of the network entity to decode the RACH preamble.

[0171] In one aspect, the method 1300 further includes outputting a threshold, wherein the threshold includes a threshold difference for each of the first UE and the second UE to determine whether the RAR message is intended for the UE. The threshold difference is between the first difference and the second difference. The first difference is the difference between the TAC and the second difference. The second difference is the TA difference. The TA difference is the difference between the first TA and the third TA of the first UE and the difference between the second TA and the fourth TA of the second UE.

[0172] In one aspect, the method 1300 further includes determining a threshold based on a characteristic associated with the first TA.

[0173] In one aspect, the method 1300 further comprises outputting a second RAR after obtaining the RACH preamble and before obtaining the PUSCH, the second RAR comprising a second TAC different from the TAC.

[0174] In one aspect, the RAR includes an access radio network temporary identifier (RA-RNTI), a random access preamble identifier (RAPID), or both, and the second RAR includes the same RA-RNTI, the same RAPID, or both.

[0175] In one aspect, obtaining the RACH preamble at 1304 includes obtaining a RACH message that also includes a PUSCH, and outputting the RAR at 1306 includes outputting a fallback RAR in the RACH message.

[0176] In one aspect, the RACH preamble transmission and the PUSCH transmission include NB-IoT EDT or SDT.

[0177] In one aspect, the network entity is or is in communication with a NTN entity.

[0178] In one aspect, method 1300 or any aspect related thereto may be performed by an apparatus such as Fig.15 The method 1300 is performed by a communication device 1500 that includes various components operable to, configured to, or adapted to perform the method 1300. The communication device 1500 is described in more detail below.

[0179] It should be noted that Fig.13 This is merely one example of a method, and other methods including fewer, additional, or alternative steps are also possible consistent with the present disclosure.

[0180] Example Communication Device

[0181] Fig.14 Depicted are aspects of an example communication device 1400. In some aspects, the communication device 1400 is user equipment, such as described above with respect to Figure 1 and Figure 3 UE 104 is described.

[0182] The communication device 1400 includes a processing system 1402 coupled to a transceiver 1408 (e.g., a transmitter and / or a receiver). The transceiver 1408 is configured to transmit and receive signals for the communication device 1400, such as various signals as described herein, via an antenna 1410. The processing system 1402 may be configured to perform processing functions for the communication device 1400, including processing signals received by the communication device 1400 and / or to be transmitted by it.

[0183] Processing system 1402 includes one or more processors 1420. In various aspects, one or more processors 1420 may represent Figure 3One or more of the receive processor 358, transmit processor 364, TX MIMO processor 366, and / or controller / processor 380 described herein. The one or more processors 1420 are coupled to the computer-readable medium / memory 1430 via the bus 1406. In some aspects, the computer-readable medium / memory 1430 is configured to store instructions (e.g., computer-executable code) that, when executed by the one or more processors 1420, cause the one or more processors 1420 to perform operations for Fig.12 The described method 1200 or any aspect related thereto. It should be noted that reference to a processor performing a function of the communication device 1400 may include one or more processors performing that function of the communication device 1400.

[0184] In the depicted example, the computer-readable medium / memory 1430 stores code (e.g., executable instructions) for determining 1431, code for sending 1432, code for receiving 1433, code for suppressing 1434, code for selecting 1435, code for applying 1436, code for adjusting 1437, and code for monitoring 1438. Processing of the codes 1431-1438 may cause the communication device 1400 to perform operations for Fig.12 The described method 1200 or any aspect related thereto.

[0185] The one or more processors 1420 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1430, including circuits 1421 for determining, circuits 1422 for sending, circuits 1423 for receiving, circuits 1424 for suppressing, circuits 1425 for selecting, circuits 1426 for applying, circuits 1427 for adjusting, and circuits 1428 for monitoring. Processing performed by circuits 1421-1428 may cause the communication device 1400 to perform operations for Fig.12 The described method 1200 or any aspect related thereto.

[0186] The various components of the communication device 1400 may be provided for performing Fig.12 The components of the described method 1200 or any aspect related thereto. For example, the components for sending, transmitting, or outputting for sending may include Figure 3 The illustrated transceiver 354 and / or antenna 352 and / or Fig.14 The transceiver 1408 and antenna 1410 of the communication device 1400 in FIG. 1400 may include Figure 3 The illustrated transceiver 354 and / or antenna 352 and / or Fig.14The transceiver 1408 and antenna 1410 of the communication device 1400 in FIG.

[0187] Fig.15 Depicted are aspects of an example communication device. In some aspects, the communication device 1500 is a network entity such as Figure 1 and Figure 3 BS102 or for Figure 2 The decomposed base station in question.

[0188] The communication device 1500 includes a processing system 1502 coupled to a transceiver 1508 (e.g., a transmitter and / or a receiver) and / or a network interface 1512. The transceiver 1508 is configured to transmit and receive signals for the communication device 1500 via an antenna 1510, such as various signals as described herein. The network interface 1512 is configured to transmit and receive signals for the communication device 1500 via a communication link (such as various signals as described herein). Figure 2 The processing system 1502 may be configured to perform processing functions of the communication device 1500, including processing signals received by the communication device 1500 and / or to be transmitted by the communication device 1500.

[0189] Processing system 1502 includes one or more processors 1520. In various aspects, one or more processors 1520 may represent Figure 3 One or more of the receive processor 338, transmit processor 320, TX MIMO processor 330, and / or controller / processor 340 described herein. The one or more processors 1520 are coupled to the computer-readable medium / memory 1530 via bus 1506. In some aspects, the computer-readable medium / memory 1530 is configured to store instructions (e.g., computer-executable code) that, when executed by the one or more processors 1520, cause the one or more processors 1520 to perform operations for Fig.13 The described method 1300 or any aspect related thereto. It should be noted that reference to a processor of the communication device 1500 performing a function may include one or more processors of the communication device 1500 performing the function.

[0190] In the depicted example, the computer readable medium / memory 1530 stores code (eg, executable instructions) for outputting 1531, code for obtaining 1532, and code for determining 1533. Processing of the codes 1531-1533 may cause the communication device 1500 to perform operations for Fig.13 The described method 1300 or any aspect related thereto.

[0191] The one or more processors 1520 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1530, including circuits 1521 for outputting, circuits 1522 for obtaining, and circuits 1523 for determining. Processing performed by circuits 1521-1523 may cause the communication device 1500 to perform operations for Fig.13 The described method 1300 or any aspect related thereto.

[0192] The various components of the communication device 1500 may be provided for performing Figure 3 The components of the described method 1300 or any aspect related thereto. The components for sending, transmitting, or outputting for sending may include Figure 3 The illustrated transceiver 332 and / or antenna 334 and / or Fig.15 The transceiver 1508 and antenna 1510 of the communication device 1500 in FIG. 1 may include Figure 3 The illustrated transceiver 332 and / or antenna 334 and / or Fig.15 The transceiver 1508 and antenna 1510 of the communication device 1500 in FIG.

[0193] Sample Clauses

[0194] Specific implementation examples are described in the following numbered clauses:

[0195] Clause 1: A method for wireless communications by a user equipment (UE), the method comprising: determining a first timing advance (TA) for sending a random access channel (RACH) preamble; determining a second TA for sending the RACH preamble, the second TA being different from the first TA; sending the RACH preamble using the second TA; receiving a random access response (RAR) message including a timing advance command (TAC); determining whether the RAR is intended for the UE based on the TAC, the first TA, and the second TA; and sending a physical uplink shared channel (PUSCH) transmission based on determining that the RAR is intended for the UE.

[0196] Clause 2: The method of clause 1, further comprising: refraining from sending a PUSCH based on determining that the RAR is not intended for the UE.

[0197] Clause 3: A method as described in any one or more of clauses 1 to 2, wherein determining the second TA includes: receiving a configuration or pre-configuration for determining the second TA; and determining the second TA based on the configuration or pre-configuration.

[0198] Clause 4: A method according to clause 3, wherein: the configuration for determining the second TA includes an offset range; and determining the second TA based on the configuration includes: selecting an offset from the offset range, and applying the offset to the first TA to determine the second TA.

[0199] Clause 5: The method of clause 4, wherein selecting the offset from the range of offsets comprises randomly selecting the offset from the range of offsets.

[0200] Clause 6: A method as described in any one or more of clauses 1 to 5, wherein the second TA is equal to or less than the first TA.

[0201] Clause 7: A method according to any one or more of clauses 1 to 6, wherein determining whether the RAR is intended for the UE comprises: determining that the RAR is intended for the UE when a first difference is less than a threshold, wherein the first difference is the difference between the TAC and a second difference, and wherein the second difference is the difference between the first TA and the second TA; and determining that the RAR is not intended for the UE when the first difference is equal to or greater than the threshold.

[0202] Clause 8: The method of clause 7, further comprising: receiving signaling configuring the threshold at the UE.

[0203] Clause 9: A method as described in any one or more of clauses 7 to 8, the method further comprising: determining the threshold based on a characteristic associated with the first TA.

[0204] Clause 10: A method as described in any one or more of clauses 7 to 9, further comprising: adjusting the threshold based on the number of random access attempts.

[0205] Clause 11: The method of clause 10, wherein adjusting the threshold based on the number of random access attempts comprises adjusting the threshold after determining that a configured threshold number of RARs are not intended for the UE.

[0206] Clause 12: A method according to any one or more of clauses 1 to 11, the method further comprising: receiving a second RAR after sending the RACH preamble code and before sending the PUSCH, the second RAR comprising a second TAC; and determining that the second RAR is not intended for the UE based on a third difference between the second TAC and a second difference between the first TA and the second TA.

[0207] Clause 13: The method of claim 12, wherein: the RAR comprises an access radio network temporary identifier (RA-RNTI), a random access preamble identifier (RAPID), or both; and the second RAR comprises the same RA-RNTI, the same RAPID, or both.

[0208] Clause 14: A method as described in any one or more of clauses 1 to 13, wherein: sending the RACH preamble comprises sending a RACH message that also includes a PUSCH; and receiving the RAR comprises receiving a fallback RAR in the RACH message.

[0209] Clause 15: The method of any one or more of clauses 1 to 14, further comprising: monitoring an entire configured RAR window, wherein one or more RARs are received in the RAR window.

[0210] Clause 16: A method as described in any one or more of clauses 1 to 15, wherein determining the first TA comprises: determining the first TA based on a location of the UE, ephemeris information, one or more configured common TA parameters, or a combination thereof.

[0211] Clause 17: A method as described in any one or more of clauses 1 to 16, wherein the RACH preamble code transmission and the PUSCH transmission include narrowband Internet of Things (NB-IoT) early data transmission (EDT) or small data transmission (SDT).

[0212] Clause 18: A method as set forth in any one or more of clauses 1 to 17, wherein the UE utilizes a non-terrestrial network (NTN) to perform a RACH procedure.

[0213] Clause 19: A method for wireless communication by a network entity, the method comprising: outputting a timing advance (TA) configuration for a first user equipment (UE) and a second UE; obtaining a first random access channel (RACH) preamble from the first UE using a first TA and obtaining a second RACH preamble from the second UE using a second TA, wherein the first RACH preamble and the second RACH preamble include the same RACH sequence; outputting a random access response (RAR) message including a timing advance command (TAC); and obtaining a physical uplink shared channel (PUSCH) transmission from the first UE or the second UE based on the TAC.

[0214] Clause 20: The method of clause 19, wherein the first RACH preamble and the second RACH preamble are obtained at different times.

[0215] Clause 21: A method as described in any one or more of clauses 19 to 20, wherein the TA configuration comprises an offset range or a TA value range.

[0216] Clause 22: The method of clause 21, further comprising: determining the offset range or the TA value range based on the ability of the network entity to decode a RACH preamble.

[0217] Clause 23: A method according to any one or more of clauses 19 to 22, the method further comprising: outputting a threshold, wherein the threshold comprises a threshold difference between the TAC and a TA difference value for each of the first UE and the second UE, to determine whether the RAR message is intended for the UE.

[0218] Clause 24: The method of clause 23, further comprising: determining the threshold based on a characteristic associated with the first TA.

[0219] Clause 25: A method as described in any one or more of clauses 19 to 24, the method further comprising: outputting a second RAR after obtaining the RACH preamble and before obtaining the PUSCH, the second RAR comprising a second TAC different from the TAC.

[0220] Clause 26: A method according to clause 25, wherein: the RAR includes an access radio network temporary identifier (RA-RNTI), a random access preamble identifier (RAPID), or both; and the second RAR includes the same RA-RNTI, the same RAPID, or both.

[0221] Clause 27: A method as described in any one or more of clauses 19 to 26, wherein: obtaining the RACH preamble comprises obtaining a RACH message that also includes a PUSCH; and outputting the RAR comprises outputting a fallback RAR in a RACH message.

[0222] Clause 28: A method as described in any one or more of clauses 19 to 27, wherein the RACH preamble code transmission and the PUSCH transmission include narrowband Internet of Things (NB-IoT) early data transmission (EDT) or small data transmission (SDT).

[0223] Clause 29: A method as described in any one or more of clauses 19 to 28, wherein the network entity is a non-terrestrial network (NTN) entity or is in communication with the NTN entity.

[0224] Clause 30: An apparatus, the apparatus comprising: a memory including executable instructions; and a processor configured to execute the executable instructions and cause the apparatus to perform the method of any one of clauses 1 to 29.

[0225] Clause 31: An apparatus comprising means for performing the method of any of clauses 1 to 29.

[0226] Clause 32: A non-transitory computer readable medium comprising executable instructions which, when executed by a processor of an apparatus, cause the apparatus to perform the method of any one of clauses 1 to 29.

[0227] Clause 33: A computer program product embodied on a computer readable storage medium, the computer program product comprising code for performing the method according to any one of clauses 1 to 29.

[0228] Additional considerations

[0229] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limited to the scope, applicability or aspects set forth in the claims. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may omit, replace or add various processes or components as appropriate. For example, the described methods may be performed in an order different from the order described, and various actions may be added, omitted or combined. In addition, the features described with respect to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such devices or methods practiced using other structures, functionality, or structures and functionality other than the various aspects of the present disclosure set forth herein or different from the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of the present invention.

[0230] The various illustrative logic blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed using a general purpose processor, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. Although a general purpose processor may be a microprocessor, in an alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC), or any other such configuration.

[0231] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items (including single members). For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0232] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, and the like. Additionally, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Additionally, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0233] The method disclosed herein includes one or more actions for implementing the method. The method actions can be interchangeable with each other without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and / or use of specific actions can be modified without departing from the scope of the claims. In addition, the various operations of the method described above can be performed by any suitable component that can perform the corresponding function. The component may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs) or processors.

[0234] The following claims are not intended to be limited to the various aspects shown herein, but should be given the full scope consistent with the language of the claims. Within the claims, unless explicitly stated, reference to an element in the singular form is not intended to mean "one and only one", but "one or more". Unless otherwise specified, the term "some" refers to one or more. Any claim element is not interpreted according to the provisions of 35 U.S.C. § 112 (f) unless the element is explicitly stated using the phrase "parts for...". All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or will be known later to a person of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims.

Claims

1. An apparatus configured for wireless communication, the apparatus comprising: a memory including computer executable instructions; and a processor configured to execute the computer executable instructions and cause the apparatus to: determining a first timing advance (TA) for sending a random access channel (RACH) preamble; determining a second TA for sending the RACH preamble, the second TA being different from the first TA; Using the second TA to send the RACH preamble; receiving a random access response (RAR) message including a timing advance command (TAC); determining whether the RAR is intended for the device based on the TAC, the first TA, and the second TA; as well as A physical uplink shared channel (PUSCH) transmission is sent based on determining that the RAR is intended for the device.

2. The apparatus of claim 1 , wherein the processor is configured to execute the computer executable instructions and further cause the apparatus to: Sending a PUSCH is refrained from based on determining that the RAR is not intended for the apparatus.

3. The apparatus of claim 1 , wherein the processor is configured to execute the computer executable instructions and cause the apparatus to determine the second TA comprises: The processor is configured to execute the computer executable instructions and cause the apparatus to: receiving a configuration or a pre-configuration for determining the second TA; as well as The second TA is determined based on the configuration or pre-configuration.

4. The device according to claim 3, wherein: The configuration for determining the second TA includes an offset range; and The processor is configured to execute the computer executable instructions and cause the apparatus to determine the second TA based on the configuration, including: the processor is configured to execute the computer executable instructions and cause the apparatus to: selecting an offset from the range of offsets; and The offset is applied to the first TA to determine the second TA.

5. The apparatus of claim 4, wherein the processor is configured to execute the computer executable instructions and cause the apparatus to select the offset from the offset range comprises: The processor is configured to execute the computer executable instructions and cause the apparatus to: The offset is randomly selected from the offset range. The apparatus of claim 1 , wherein the second TA is equal to or smaller than the first TA.

7. The apparatus of claim 1, wherein the processor is configured to execute the computer-executable instructions and cause the apparatus to determine whether the RAR is intended for the apparatus comprises: The processor is configured to execute the computer executable instructions and cause the apparatus to: determining that the RAR is intended for the device when a first difference is less than a threshold, wherein the first difference is a difference between the TAC and a second difference between the first TA and the second TA; as well as When the first difference is equal to or greater than the threshold, it is determined that the RAR is not intended for the device.

8. The apparatus of claim 7, wherein the processor is configured to execute the computer-executable instructions and further cause the apparatus to receive signaling to configure the threshold at the apparatus.

9. The apparatus of claim 7, wherein the processor is configured to execute the computer-executable instructions and further cause the apparatus to determine the threshold based on a characteristic associated with the first TA.

10. The apparatus of claim 7, wherein the processor is configured to execute the computer-executable instructions and further cause the apparatus to adjust the threshold based on a number of random access attempts.

11. The apparatus of claim 10, wherein adjusting the threshold based on the number of random access attempts comprises adjusting the threshold after determining that a configured threshold number of RARs are not intended for the apparatus.

12. The apparatus of claim 1, wherein the processor is configured to execute the computer executable instructions and further cause the apparatus to: receiving a second RAR after transmitting the RACH preamble and before transmitting the PUSCH, the second RAR including a second TAC; and A determination is made that the second RAR is not intended for the device based on a third difference value, wherein the third difference value is a difference between the second TAC and a second difference value between the first TA and the second TA.

13. The device according to claim 12, wherein: The RAR includes an access radio network temporary identifier (RA-RNTI), a random access preamble identifier (RAPID), or both; and The second RAR includes the same RA-RNTI, the same RAPID, or both.

14. The device according to claim 1, wherein: Sending the RACH preamble includes sending a RACH message that also includes a PUSCH; and Receiving the RAR includes receiving a fallback RAR in a RACH message.

15. The apparatus of claim 1, wherein the processor is configured to execute the computer executable instructions and further cause the apparatus to: An entire configured RAR window is monitored, wherein one or more RARs are received in the RAR window.

16. The apparatus of claim 1, wherein determining the first TA comprises: The first TA is determined based on a location of the apparatus, ephemeris information, one or more configured common TA parameters, or a combination thereof.

17. The apparatus of claim 1, wherein the RACH preamble transmission and the PUSCH transmission comprise a narrowband Internet of Things (NB-IoT) early data transmission (EDT) or a small data transmission (SDT).

18. The apparatus of claim 1, wherein the UE utilizes a non-terrestrial network (NTN) to perform a RACH procedure.

19. An apparatus configured for wireless communication, the apparatus comprising: a memory including computer executable instructions; and a processor configured to execute the computer executable instructions and cause the apparatus to: outputting a timing advance (TA) configuration for a first user equipment (UE) and a second UE; obtaining a first random access channel (RACH) preamble from the first UE using a first TA and obtaining a second RACH preamble from the second UE using a second TA, wherein the first RACH preamble and the second RACH preamble include the same RACH sequence; outputting a random access response (RAR) message including a timing advance command (TAC); and A physical uplink shared channel (PUSCH) transmission is obtained from the first UE or the second UE based on the TAC.

20. The apparatus of claim 19, wherein the first RACH preamble and the second RACH preamble are obtained at different times.

21. The apparatus of claim 19, wherein the TA configuration comprises an offset range or a TA value range.

22. The apparatus of claim 21, wherein the processor is configured to execute the computer executable instructions and further cause the apparatus to: The offset range or the TA value range is determined based on a capability of the apparatus to decode a RACH preamble.

23. The apparatus of claim 19, wherein the processor is configured to execute the computer executable instructions and further cause the apparatus to: A threshold is output, wherein the threshold comprises a threshold difference between the TAC and a TA difference for each of the first UE and the second UE to determine whether the RAR message is intended for the UE.

24. The apparatus of claim 23, wherein the processor is configured to execute the computer executable instructions and further cause the apparatus to: The threshold is determined based on a characteristic associated with the first TA.

25. The apparatus of claim 19, wherein the processor is configured to execute the computer executable instructions and further cause the apparatus to: A second RAR is output after obtaining the RACH preamble and before obtaining the PUSCH, the second RAR including a second TAC different from the TAC.

26. The apparatus of claim 25, wherein: The RAR includes an access radio network temporary identifier (RA-RNTI), a random access preamble identifier (RAPID), or both; and The second RAR includes the same RA-RNTI, the same RAPID, or both.

27. The apparatus of claim 19, wherein: The processor being configured to execute the computer-executable instructions and causing the apparatus to obtain the RACH preamble includes: the processor being configured to execute the computer-executable instructions and causing the apparatus to obtain a RACH message further including a PUSCH; and The processor being configured to execute the computer-executable instructions and cause the apparatus to output the RAR includes the processor being configured to execute the computer-executable instructions and cause the apparatus to output a fallback RAR in a RACH message.

28. The apparatus of claim 19, wherein the RACH preamble transmission and the PUSCH transmission comprise a narrowband Internet of Things (NB-IoT) early data transmission (EDT) or a small data transmission (SDT).

29. A method for wireless communication by a user equipment (UE), the method comprising: determining a first timing advance (TA) for sending a random access channel (RACH) preamble; determining a second TA for sending the RACH preamble, the second TA being different from the first TA; Using the second TA to send the RACH preamble; receiving a random access response (RAR) message including a timing advance command (TAC); determining whether the RAR is intended for the UE based on the TAC, the first TA, and the second TA; as well as A physical uplink shared channel (PUSCH) transmission is sent based on determining that the RAR is intended for the UE.

30. A method for wireless communication by a network entity, the method comprising: outputting a timing advance (TA) configuration for a first user equipment (UE) and a second UE; obtaining a first random access channel (RACH) preamble from the first UE using a first TA and obtaining a second RACH preamble from the second UE using a second TA, wherein the first RACH preamble and the second RACH preamble include the same RACH sequence; outputting a random access response (RAR) message including a timing advance command (TAC); and A physical uplink shared channel (PUSCH) transmission is obtained from the first UE or the second UE based on the TAC.

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