Method and apparatus for random access resource management

Abstract

A method performed by a User Equipment (UE) for performing a random access resource management operation is provided. The method receives, from a serving cell, a first configuration indicating a baseline Physical Random Access Channel (PRACH) resource. The method receives, from the serving cell, a second configuration indicating at least one of a first additional PRACH resource for a contention-free random access (CFRA) procedure or a second additional PRACH resource for a contention-based random access (CBRA) procedure. The method receives, from the serving cell, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource.　

Description

METHOD AND APPARATUS FOR RANDOM ACCESS RESOURCE MANAGEMENT

[0001] The present disclosure is related to wireless communication and, more specifically, to a User Equipment (UE), Base Station (BS), and method for performing a random access resource management operation in the wireless communication networks.

[0002] Various efforts have been made to improve different aspects of wireless communication for the cellular wireless communication systems, such as the 5thGeneration (5G) New Radio (NR), by improving data rate, latency, reliability, and mobility. The 5G NR system is designed to provide flexibility and configurability to optimize network services and types, accommodating various use cases, such as enhanced Mobile Broadband (eMBB), massive Machine-Type Communication (mMTC), and Ultra-Reliable and Low-Latency Communication (URLLC). As the demand for radio access continues to grow, however, there exists a need for further improvements in the next-generation wireless communication systems, such as improvements in random access resource management.

[0003] The present disclosure is related to a UE, a BS, and a method for performing a random access resource management operation in the wireless communication networks.

[0004] In a first aspect of the present disclosure, a UE for performing a random access resource management operation is provided. The UE includes at least one processor and at least one non-transitory computer-readable medium that is coupled to the at least one processor and that stores one or more computer-executable instructions. The computer-executable instructions, when executed by the at least one processor, cause the UE to: receive, from a serving cell, a first configuration indicating a baseline Physical Random Access Channel (PRACH) resource; receive, from the serving cell, a second configuration indicating at least one of a first additional PRACH resource for a contention-free random access (CFRA) procedure or a second additional PRACH resource for a contention-based random access (CBRA) procedure; and receive, from the serving cell, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource.

[0005] In some implementations of the first aspect, the first indication is carried by a paging Downlink Control Information (DCI) with Cyclic Redundancy Check (CRC) scrambled by a Paging-Radio Network Temporary Identifier (P-RNTI) or a Medium Access Control (MAC) Control Element (CE).

[0006] In some implementations of the first aspect, the second configuration includes a second indication for indicating whether the at least one of the first additional PRACH resource or the second additional PRACH resource is activated or deactivated by default.

[0007] In some implementations of the first aspect, the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: receive, from the serving cell, a Downlink Control Information (DCI) to initiate a Physical Downlink Control Channel (PDCCH)-order random access (RA) procedure on a target PRACH resource associated with one of the first and second additional PRACH resources; and perform the PDCCH-order RA procedure with the serving cell on the target PRACH resource. The PDCCH-order RA procedure is the CFRA procedure when the target PRACH resource is associated with the first additional PRACH resource. The PDCCH-order RA procedure is the CBRA procedure when the target PRACH resource is associated with the second additional PRACH resource. The second configuration includes a Physical Cell Identifier (PCI) of the serving cell. The at least one of the first additional PRACH resource or the second additional PRACH resource is associated with the PCI of the serving cell.

[0008] In some implementations of the first aspect, the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: perform the CBRA procedure with the serving cell on a target PRACH resource associated with the second additional PRACH resource that is activated by the first indication, in response to determining that the CBRA procedure is triggered for a feature included in the second configuration associated with the second additional PRACH resource.

[0009] In some implementations of the first aspect, the first configuration includes a parameter having a first value associated with the baseline PRACH resource. The second configuration includes the parameter having a second value associated with the first additional PRACH resource or the second additional PRACH resource. The first value is different from the second value. The parameter is one of a threshold for a Downlink Reference Signal Received Power (DL-RSRP), a numerology, a periodicity, a bandwidth part (BWP), an uplink carrier, an association with Synchronization Signal Blocks (SSBs), multiple features, or multiple feature priorities corresponding to the features.

[0010] In some implementations of the first aspect, the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: store the second configuration as part of a UE inactive context upon transitioning from a Radio Resource Control (RRC) Connected state to an RRC Inactive state; and resume the stored second configuration upon transitioning from the RRC Inactive state to the RRC Connected state.

[0011] In a second aspect of the present application, a BS for configuring a random access resource is provided. The BS includes at least one processor and at least one non-transitory computer-readable medium that is coupled to the at least one processor and that stores one or more computer-executable instructions. The computer-executable instructions, when executed by the at least one processor, cause the BS to: transmit, via a serving cell to a UE, a first configuration indicating a baseline PRACH resource; transmit, via the serving cell to the UE, a second configuration indicating at least one of a first additional PRACH resource for a CFRA procedure or a second additional PRACH resource for a CBRA procedure; and transmit, via the serving cell to the UE, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource.

[0012] In some implementations of the second aspect, the first indication is carried by a paging DCI with CRC scrambled by a P-RNTI or a MAC CE.

[0013] In some implementations of the second aspect, the second configuration includes a second indication for indicating whether the at least one of the first additional PRACH resource or the second additional PRACH resource is activated or deactivated by default.

[0014] In some implementations of the second aspect, the one or more computer-executable instructions, when executed by the at least one processor, further cause the BS to: transmit, to the UE, a DCI to initiate a PDCCH-order RA procedure on a target PRACH resource associated with one of the first and second additional PRACH resources. The UE performs the PDCCH-order RA procedure with the serving cell on the target PRACH resource. The PDCCH-order RA procedure is the CFRA procedure when the target PRACH resource is associated with the first additional PRACH resource. The PDCCH-order RA procedure is the CBRA procedure when the target PRACH resource is associated with the second additional PRACH resource. The DCI is scrambled by a C-RNTI of the UE. The second configuration includes a PCI of the serving cell. The at least one of the first additional PRACH resource or the second additional PRACH resource is associated with the PCI of the serving cell.

[0015] In some implementations of the second aspect, the UE performs the CBRA procedure with the serving cell on a target PRACH resource associated with the second additional PRACH resource that is activated by the first indication, in response to determining that the CBRA procedure is triggered for a feature included in the second configuration associated with the second additional PRACH resource.

[0016] In some implementations of the second aspect, the first configuration includes a parameter having a first value associated with the baseline PRACH resource. The second configuration includes the parameter having a second value associated with the first additional PRACH resource or the second additional PRACH resource. The first value is different from the second value. The parameter is one of a threshold for a DL-RSRP, a numerology, a periodicity, a BWP, an uplink carrier, an association with SSBs, multiple features, or multiple feature priorities corresponding to the features.

[0017] In some implementations of the second aspect, the UE stores the second configuration as part of a UE inactive context upon transitioning from an RRC Connected state to an RRC Inactive state, and the UE resumes the stored second configuration upon transitioning from the RRC Inactive state to the RRC Connected state.

[0018] In a third aspect of the present application, a method performed by a UE for performing a random access resource management operation is provided. The method includes receiving, from a serving cell, a first configuration indicating a baseline PRACH resource; receiving, from the serving cell, a second configuration indicating at least one of a first additional PRACH resource for a CFRA procedure or a second additional PRACH resource for a CBRA procedure; and receiving, from the serving cell, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource.

[0019] Aspects of the present disclosure are best understood from the following detailed disclosure when read with the accompanying drawings. Various features are not drawn to scale. Dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.

[0020] FIG. 1 is a timing diagram illustrating baseline and additional PRACH resources, according to an example implementation of the present disclosure.

[0021] FIG. 2 is a timing diagram illustrating a dynamic PRACH adaptation related to a cell Discontinuous Reception (DRX) operation, according to an example implementation of the present disclosure.

[0022] FIG. 3 is a flowchart illustrating a method / process performed by a UE for performing a random access resource management operation, according to an example implementation of the present disclosure.

[0023] FIG. 4 is a flowchart illustrating a method / process performed by a BS for configuring a random access resource, according to an example implementation of the present disclosure.

[0024] FIG. 5 is a block diagram illustrating a node for wireless communication, according to an example implementation of the present disclosure.

[0025] Some of the abbreviations used in the present disclosure include: 3GPP　　　　　　　　　　　　3rd Generation Partnership Project 5G　　　　　　　　　　　　5th generation 5GC　　　　　　　　　　　　5G Core Network AMF　　　　　　　　　　　　Access and Mobility Management Function ASN.1　　　　　　　　　　　　Abstract Syntax Notation One BWP　　　　　　　　　　　　Bandwidth Part BS　　　　　　　　　　　　Base Station CA　　　　　　　　　　　　Carrier Aggregation CBRA　　　　　　　　　　　　Contention-Based Random Access CC　　　　　　　　　　　　Component Carrier CFRA　　　　　　　　　　　　Contention-Free Random Access CN　　　　　　　　　　　　Core Network CRC　　　　　　　　　　　　Cyclic Redundancy Check C-RNTI　　　　　　　　　　　　Cell Radio Network Temporary Identifier CSC　　　　　　　　　　　　Cell Switch Command DC　　　　　　　　　　　　Dual Connectivity DCI　　　　　　　　　　　　Downlink Control Information DL　　　　　　　　　　　　Downlink DRX　　　　　　　　　　　　Discontinuous Reception DTX　　　　　　　　　　　　Discontinuous Transmission EPC　　　　　　　　　　　　Evolved Packet Core eRedCap　　　　　　　　　　　　Enhanced Reduced Capability E-UTRA　　　　　　　　　　　　Evolved Universal Terrestrial Radio Access FR　　　　　　　　　　　　Frequency Range GNSS　　　　　　　　　　　　Global Navigation Satellite System IAB　　　　　　　　　　　　Integrated Access and Backhaul IAB-MT　　　　　　　　　　　　IAB Mobile Termination ID　　　　　　　　　　　　Identifier IE　　　　　　　　　　　　Information Element L1 / L2 / L3　　　　　　　　　　　　Layer 1 / Layer 2 / Layer 3 LTE　　　　　　　　　　　　Long Term Evolution LTM　　　　　　　　　　　　Layer1 / Layer2 Triggered Mobility MAC　　　　　　　　　　　　Medium Access Control MAC CE　　　　　　　　　　　　MAC Control Element MCG　　　　　　　　　　　　Master Cell Group MN　　　　　　　　　　　　Master Node MO-SDT　　　　　　　　　　　　Mobile Originated SDT MR-DC　　　　　　　　　　　　Multi-RAT Dual Connectivity Msg　　　　　　　　　　　　Message NES　　　　　　　　　　　　Network Energy Saving NR　　　　　　　　　　　　New RAT / Radio NUL　　　　　　　　　　　　Normal Uplink NW　　　　　　　　　　　　Network P-RNTI　　　　　　　　　　　　Paging-RNTI PCell　　　　　　　　　　　　Primary Cell PCI　　　　　　　　　　　　Physical Cell Identifier PDCCH　　　　　　　　　　　　Physical Downlink Control Channel PDSCH　　　　　　　　　　　　Physical Downlink Shared Channel PEI　　　　　　　　　　　　Paging Early Indication PHY　　　　　　　　　　　　Physical PRACH　　　　　　　　　　　　Physical Random Access Channel PRB　　　　　　　　　　　　Physical Resource Block PSCell　　　　　　　　　　　　Primary SCG Cell PUCCH　　　　　　　　　　　　Physical Uplink Control Channel PUSCH　　　　　　　　　　　　Physical Uplink Shared Channel RA　　　　　　　　　　　　Random Access RACH　　　　　　　　　　　　Random Access Channel RAN　　　　　　　　　　　　Radio Access Network RAT　　　　　　　　　　　　Radio Access Technology RedCap　　　　　　　　　　　　Reduced Capability RF　　　　　　　　　　　　Radio Frequency RNTI　　　　　　　　　　　　Radio Network Temporary Identifier RO　　　　　　　　　　　　RACH Occasion RRC　　　　　　　　　　　　Radio Resource Control RS　　　　　　　　　　　　Reference Signal RSRP　　　　　　　　　　　　Reference Signal Received Power SCell　　　　　　　　　　　　Secondary Cell SCG　　　　　　　　　　　　Secondary Cell Group SDT　　　　　　　　　　　　Small Data Transmission SI　　　　　　　　　　　　System Information SIB　　　　　　　　　　　　System Information Block SN　　　　　　　　　　　　Secondary Node SpCell　　　　　　　　　　　　Special Cell SRB　　　　　　　　　　　　Signaling Radio Bearer SSB　　　　　　　　　　　　Synchronization Signal Block SUL　　　　　　　　　　　　Supplementary Uplink TA　　　　　　　　　　　　Timing Advance TS　　　　　　　　　　　　Technical Specification Tx　　　　　　　　　　　　Transmission UE　　　　　　　　　　　　User Equipment UL　　　　　　　　　　　　Uplink URLLC　　　　　　　　　　　　Ultra Reliable Low Latency Communication WUS　　　　　　　　　　　　Wake-Up Signal

[0026] The following contains specific information related to implementations of the present disclosure. The drawings and their accompanying detailed disclosure are merely directed to implementations. However, the present disclosure is not limited to these implementations. Other variations and implementations of the present disclosure will be obvious to those skilled in the art.

[0027] Unless noted otherwise, like or corresponding elements among the drawings may be indicated by like or corresponding reference numerals. Moreover, the drawings and illustrations in the present disclosure are generally not to scale and are not intended to correspond to actual relative dimensions.

[0028] For the purposes of consistency and ease of understanding, like features may be identified (although, in some examples, not illustrated) by the same numerals in the drawings. However, the features in different implementations may be different in other respects and may not be narrowly confined to what is illustrated in the drawings.

[0029] References to “one implementation,” “an implementation,” “example implementation,” “various implementations,” “some implementations,” “implementations of the present application,” etc., may indicate that the implementation(s) of the present application so described may include a particular feature, structure, or characteristic, but not every possible implementation of the present application necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrase “In some implementations,” or “in an example implementation,” “an implementation,” do not necessarily refer to the same implementation, although they may. Moreover, any use of phrases like “implementations” in connection with “the present application” are never meant to characterize that all implementations of the present application must include the particular feature, structure, or characteristic, and should instead be understood to mean “at least some implementations of the present application” includes the stated particular feature, structure, or characteristic. The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the equivalent.

[0030] The expression “at least one of A, B and C” or “at least one of the following: A, B and C” means “only A, or only B, or only C, or any combination of A, B and C.” The terms “system” and “network” may be used interchangeably. The term “and / or” is only an association relationship for describing associated objects and represents that three relationships may exist such that A and / or B may indicate that A exists alone, A and B exist at the same time, or B exists alone. The character “ / ” generally represents that the associated objects are in an “or” relationship.

[0031] For the purposes of explanation and non-limitation, specific details, such as functional entities, techniques, protocols, and standards, are set forth for providing an understanding of the disclosed technology. In other examples, detailed disclosure of well-known methods, technologies, systems, and architectures are omitted so as not to obscure the present disclosure with unnecessary details.

[0032] Persons skilled in the art will immediately recognize that any network function(s) or algorithm(s) disclosed may be implemented by hardware, software, or a combination of software and hardware. Disclosed functions may correspond to modules which may be software, hardware, firmware, or any combination thereof.

[0033] A software implementation may include computer-executable instructions and / or Artificial Intelligence (AI) / Machine Learning (ML) module(s) stored on a computer-readable medium, such as memory or other type of storage devices. One or more microprocessors or general-purpose computers with communication processing capability may be programmed with corresponding computer-executable instructions and perform the disclosed network function(s), AI / ML module(s), or algorithm(s). The AI / ML module(s) may be implemented with a supervised learning approach, a semi-supervised learning approach, an unsupervised learning approach (e.g., Transductive approach and Inductive approach), a federated learning approach, or a reinforcement learning (RL) approach, but the present disclosure is not limited thereto. The computer-executable instructions associated with the AI module(s) and / or the ML module(s) may include but are not limited to, data management instructions (e.g., collection instructions, validation instructions…etc.), model monitoring and management instructions (e.g., NW key performance indicators (KPIs) monitoring, model input / output monitoring, model selection / switching / update / upload / download, model (de)activation, model identification, functionality selection…etc.), and / or pre-process input instructions.

[0034] The microprocessors or general-purpose computers may include Application-Specific Integrated Circuits (ASICs), programmable logic arrays, Central Processing Units (CPUs), Tensor Processing Units (TPUs), Graphics Processing Units (GPUs), General-purpose computing on GPUs (GPGPU, or less often GPGP), and / or using one or more Digital Signal Processors (DSPs). Although some of the disclosed implementations are oriented to software installed and executing on computer hardware, alternative implementations implemented as firmware, as hardware, or as a combination of hardware and software are well within the scope of the present disclosure. The computer-readable medium may include, but is not limited to, Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), High Bandwidth Memory (HBM), Magnetoresistive Random Access Memory (MRAM), Ferroelectric Random Access Memory (FRAM), Resistive Random Access Memory (RRAM), Read-Only Memory (ROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), flash memory (or other memory technology), Compact Disc Read-Only Memory (CD-ROM) , Digital Versatile Disks (DVD) (or other optical disk storage), magnetic cassettes, magnetic tape, magnetic disk storage (or other magnetic storage devices), or any other equivalent medium capable of storing computer-readable instructions.

[0035] A radio communication network architecture such as a Long-Term Evolution (LTE) system, an LTE-Advanced (LTE-A) system, an LTE-Advanced Pro system, or a 5G NR Radio Access Network (RAN), 5G-Advanced (5G-A) system, or an open radio access network (O-RAN) may typically include at least one base station (BS), at least one UE, and one or more optional network elements that provide connection within a network. The BS and one or more optional network elements enable the UE to access a radio network. The UE may communicate with the network, such as a Core Network (CN), an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial RAN (E-UTRAN), a Next-Generation Core (NGC), a 5G Core (5GC), or an internet via a RAN established by one or more BSs and the network elements / functions.

[0036] A UE may include, but is not limited to, a mobile station, a mobile terminal or device, or a user communication radio terminal. The UE may be a portable radio equipment that includes, but is not limited to, a mobile phone, a tablet, a wearable device, a sensor, a vehicle, a virtual reality (VR) device, an augmented (AR) device, an Internet of Things (IoT) device, an unmanned aerial vehicle (UAV), or a Personal Digital Assistant (PDA) with wireless communication capability. The UE may be configured to receive and transmit signals over an air interface to one or more cells in a RAN. In some implementations, the UE may be an AI / ML-enabled device and / or an AI / ML capable device that is equipped with AI module(s) and / or ML module(s).

[0037] The BS may be configured to provide communication services according to at least a Radio Access Technology (RAT), such as Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM) that is often referred to as 2G, GSM Enhanced Data rates for GSM Evolution (EDGE) RAN (GERAN), General Packet Radio Service (GPRS), Universal Mobile Telecommunication System (UMTS) that is often referred to as 3G based on basic Wideband-Code Division Multiple Access (W-CDMA), High-Speed Packet Access (HSPA), LTE, LTE-A, evolved / enhanced LTE (eLTE) that is LTE connected to 5GC, NR (often referred to as 5G), 5G-A, and / or LTE-A Pro. However, the scope of the present disclosure is not limited to these protocols.

[0038] The BS may include, but is not limited to, a node B (NB) in the UMTS, an evolved node B (eNB) in LTE or LTE-A, a radio network controller (RNC) in UMTS, a BS controller (BSC) in the GSM / GERAN, a next-generation eNB (ng-eNB) in an Evolved Universal Terrestrial Radio Access (E-UTRA) BS in connection with 5GC, a next-generation Node B (gNB) in the 5G-RAN or in the 5G Access Network (5G-AN), or any other apparatus capable of controlling radio communication and managing radio resources within a cell. The BS may serve one or more UEs via a radio interface. Although the gNB is used as an example in some implementations within the present disclosure, it should be noted that the disclosed implementations may also be applied to other types of base stations. In some implementations, the BS may be an AI / ML-enabled device and / or an AI / ML capable device that is equipped with AI module(s) and / or ML module(s).

[0039] The BS may be operable to provide radio coverage to a specific geographical area using multiple cells forming the RAN. The BS may support the operations of the cells. Each cell may be operable to provide services to at least one UE within its radio coverage.

[0040] Each cell (often referred to as a serving cell) may provide services to serve one or more UEs within its radio coverage such that each cell schedules the downlink (DL) and optionally uplink (UL) resources to at least one UE within its radio coverage for DL and optionally UL packet transmissions. The BS may communicate with one or more UEs in the radio communication system via the cells.

[0041] A cell may allocate sidelink (SL) resources for supporting the Proximity Services (ProSe), LTE SL services, LTE / NR sidelink communication services, LTE / NR sidelink discovery services, and / or LTE / NR Vehicle-to-Everything (V2X) services. In addition, a cell may allocate DL and / or UL resources for supporting Multicast / Broadcast Service (MBS) services, Non-Terrestrial Networks (NTN) services, positioning services, power serving services and / or Network Energy Saving (NES) services.

[0042] In Multi-RAT Dual Connectivity (MR-DC) cases, the primary cell of a Master Cell Group (MCG) or a Secondary Cell Group (SCG) may be referred to as a Special Cell (SpCell). A Primary Cell (PCell) may include the SpCell of an MCG. A Primary SCG Cell (PSCell) may include the SpCell of an SCG. MCG may include a group of serving cells associated with the Master Node (MN), including the SpCell and optionally one or more Secondary Cells (SCells). An SCG may include a group of serving cells associated with the Secondary Node (SN), including the SpCell and optionally one or more SCells.

[0043] As discussed above, the frame structure for NR may support flexible configurations for accommodating various next generation (e.g., 5G) communication requirements, such as Enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), and Ultra-Reliable and Low-Latency Communication (URLLC), while fulfilling high reliability, high data rate, and low latency requirements. The Orthogonal Frequency-Division Multiplexing (OFDM) technology in the 3GPP may serve as a baseline for an NR waveform. The scalable OFDM numerology, such as adaptive sub-carrier spacing, channel bandwidth, and Cyclic Prefix (CP), may also be used.

[0044] Two coding schemes may be considered for NR, specifically, Low-Density Parity-Check (LDPC) code and Polar Code. The coding scheme adaption may be configured based on channel conditions and / or service applications.

[0045] At least the DL transmission data, a guard period, and UL transmission data should be included in a transmission time interval (TTI) of a single NR frame. The respective portions of the DL transmission data, the guard period, and the UL transmission data should also be configurable based on, for example, the network dynamics of NR. SL resources may also be provided in an NR frame to support ProSe services or V2X services.

[0046] Any two or more than two of the following paragraphs, (sub)-bullets, points, actions, behaviors, terms, or claims described in the present disclosure may be combined logically, reasonably, and properly to form a specific method.

[0047] Any sentence, paragraph, (sub)-bullet, point, action, behaviors, terms, or claims described in the present disclosure may be implemented independently and separately to form a specific method.

[0048] Dependency, e.g., “based on”, “more specifically”, “preferably”, “in one embodiment”, “in some implementations”, etc., in the present disclosure is just one possible example which would not restrict the specific method.

[0049] In some implementations, all the designs / embodiment / implementations introduced within this disclosure are not limited to be applied for dealing with the problems discussed within this disclosure. For example, the described embodiments may be applied to solve other problems that exist in the RAN of wireless communication systems. In some implementations, all of the numbers listed within the designs / embodiment / implementations introduced within this disclosure are just examples and for illustration, for example, of how the described methods are executed.

[0050] The terms, definitions, and abbreviations as given in the present disclosure are either imported from existing documentation (e.g., European Telecommunications Standards Institute (ETSI), International Telecommunication Union (ITU), or elsewhere) or newly created by 3GPP experts whenever the need for precise vocabulary is identified.

[0051] Examples of some selected terms in the present disclosure are provided as follows.

[0052] RACH-ConfigCommon: The IE RACH-ConfigCommon is used to specify the cell specific random-access parameters. IEs included in the IE RACH-ConfigCommon and related field descriptions may be found in the 3GPP TS 38.331 V18.2.0.

[0053] DCI format for PDCCH order PRACH transmission: If the CRC of the DCI format 1_0 is scrambled by C-RNTI and the “Frequency domain resource assignment” field are of all ones, the DCI format 1_0 is for random access procedure initiated by a PDCCH order. The fields in the DCI format and related description may be found in the 3GPP TS 38.212 V18.3.0.

[0054] PRACH Enhancements for Network Energy Saving (NES)

[0055] For adaptation of PRACH in time-domain, the following adaptation mechanisms may be considered. Adaptation based on configuration of additional or different PRACH resources for NES-capable UEs in addition to PRACH resources for legacy UEs (if any). The NES-capable UEs may use both additional PRACH resources and PRACH resources for legacy UEs.

[0056] For the additional PRACH resources, the following adaptation mechanisms may be considered. Adaptation of PRACH resource periodicity / PRACH occasion, adaptation at PRACH configuration / association period / association pattern period level and SSB to RO mapping cycle, adaptation based on extending cell DRX operation for PRACH, and concentrating ROs in time domain.

[0057] The present disclosure describes the following aspects regarding the PRACH resource adaptation.

[0058] - The definition / implementations of baseline / additional PRACH resource configuration. The disclosed implementations may describe details of baseline / additional PRACH resource, the reusability / differentiation of baseline PRACH resource / additional PRACH resource, UL carrier / BWP design, additional features, and overlapping conditions.

[0059] - Configuration / activation / deactivation / mute / unmute of the baseline / additional PRACH resource. The disclosed implementations may describe configuration via RRC signaling / system information (e.g., a new SIB X), activation / deactivation / mute / unmute via MAC CE / DCI, specific DCI design (e.g., PDCCH order DCI during LTM operation), specific MAC CE design (e.g., LTM CSC MAC CE design).

[0060] - The impact of cell DRX operation for the baseline / additional PRACH resource.

[0061] - The impact on the LTM operation.

[0062] - Other features, such as additional features related to preambles and two types of PRACH resource, and IAB.

[0063] - Joint impact between the SSB adaptation / PRACH adaptation for network energy saving.

[0064] FIG. 1 is a timing diagram 100 illustrating baseline and additional PRACH resources, according to an example implementation of the present disclosure. In some implementations, a PRACH configuration may indicate a baseline PRACH resource and an additional PRACH resource. As illustrated in FIG. 1, there may be first resource blocks 102 corresponding to a baseline PRACH resource, second resource blocks 104 corresponding to an additional PRACH resource, and third resource block 106 corresponding to an additional PRACH resource that may be dynamically activated or deactivated. Each resource block of the PRACH illustrated in FIG. 1 may be associated with one or more SSB burst sets.

[0065] For adaptation of PRACH in the time domain, at least the following implementations may be supported. In some implementations, there may be no time-domain overlap between the additional PRACH resources configured for NES-capable UEs and the PRACH resources configured for legacy UEs. In some implementations, the additional PRACH resources for NES-capable UEs may overlap with the legacy PRACH resources in the time domain but not in the frequency domain. In some implementations, the additional PRACH resources for NES-capable UEs and the legacy PRACH resources may be separated such that there is no overlap in either the time or frequency domain. Additional conditions may be defined to support these implementations. Additionally, full or partial overlap of the additional PRACH resources and the legacy PRACH resources in both time and frequency domains may be allowed in some implementations. The described implementations do not preclude the possibility that the configuration of additional PRACH resources for NES-capable UEs may include or reuse the legacy PRACH resources.

[0066] PRACH Resource Configurations

[0067] The present disclosure describes two PRACH resource configurations, including a baseline PRACH resource configuration and an additional PRACH resource configuration.

[0068] The baseline PRACH resource or resource configuration may be accessible to legacy UEs (e.g., non-NES capable UEs). In some implementations, the baseline PRACH resource configuration may only be accessible to the non-NES-capable UEs. In some other implementations, the baseline PRACH resource configuration may be accessible / reserved to both the NES-capable UEs and the non-NES-capable UEs.

[0069] The additional PRACH resource or resource configuration may be accessible to NES-capable UEs. In some implementations, the additional PRACH resource configuration may only be accessible to the NES-capable UEs. In some other implementations, the additional PRACH resource configuration may be accessible / reserved to both the NES-capable UEs and the non-NES-capable UEs.

[0070] In some implementations, whether a baseline / additional PRACH resource configuration is accessible to an NES-capable UE / non-NES-capable UE may be configurable by the serving RAN. In some implementations, whether a baseline / additional PRACH resource configuration is accessible to an NES-capable UE / non-NES-capable UE may be predefined by the technical specification.

[0071] In some implementations, the additional PRACH resource configuration may include all the possible combinations of the PRACH resource configuration for Msg1 transmission (e.g., for a 4-step RA procedure) and PRACH resource configuration for MsgA transmission (e.g., for a 2-step RA procedure). In some implementations, the additional PRACH resource configuration may only be supported for Msg1 transmission or MsgA transmission.

[0072] In some implementations, the additional PRACH resource configuration may indicate at least one of a first additional PRACH resource for a CFRA procedure or a second additional PRACH resource for a CBRA procedure. In some implementations, the additional PRACH configuration may include an indication for indicating whether the at least one of the first additional PRACH resource or the second additional PRACH resource is activated or deactivated by default.

[0073] In some implementations, the additional PRACH resource configuration and the baseline PRACH resource configuration may differ in at least one of the following parameters: PRACH resource periodicity / offset value in time domain (e.g., symbol), PRACH occasion, associated SSB burst sets / associated SSB direction, SSB to RO mapping cycle, UL BWP, associated / paired DL-BWPs. In some implementations, the additional PRACH resource configuration and the baseline PRACH resource configuration may differ in at least one of the following parameters: a threshold for a DL-RSRP, a numerology, a periodicity, a BWP, an uplink carrier, an association with SSBs, multiple features, or multiple feature priorities corresponding to the features.

[0074] In some implementations, the additional PRACH resources may be configured to one or more UEs via at least one of the following approaches.

[0075] Approach 1: No additional adaptation mechanism. The additional PRACH resources may be provided by semi-static signaling, such as RRC reconfiguration, broadcasting system information, or via an on-demand SI procedure.

[0076] Approach 2: L1 signaling-based adaptation to indicate whether the additional PRACH resources provided by semi-static signaling are available or not. In some implementations, the serving RAN may activate / deactivate the additional PRACH resources by re-using existing DCI formats or creating new DCI formats.

[0077] Approach 3: Adaptation of PRACH transmission according to predefined condition(s), for example, based on the additional features applied by the UE (e.g., RedCap, eRedcap, SDT, network slice, Msg3 repetition, Msg1 repetitions). In some implementations, the predefined conditions may also include RRC state transitions, L3 mobility event (e.g., handover, conditional handover), and L1 / L2 mobility (e.g., LTM operation). In some implementations, the SSB may be turned off and the PRACH resource may be unavailable.

[0078] Approach 4: L1-based adaptation to indicate adaptation of the additional PRACH resources provided by semi-static signaling by muting ROs. The muting may be in SSB-to-RO mapping cycle level, PRACH association period level, or PRACH association pattern period level. In some implementations, existing DCI formats may be reused.

[0079] Approach 5: Enhanced cell DRX

[0080] The DCI for dynamic PRACH adaptation may be in at least one of the following formats: paging DCI, Paging Early Indication (PEI), PDCCH order DCI for UE early uplink synchronization (e.g., for LTM operation), a new DCI similar to the PEI.

[0081] In some implementations, the DCI may indicate whether an additional PRACH resource is turned on / turned off. In some implementations, the DCI may indicate which parameter to be applied to the additional PRACH resource. For example, the DCI may indicate a prach-ConfigurationIndex directly or indicate an index / value associated with a pre-configured prach-ConfigurationIndex provided to the UE.

[0082] In some implementations, the search space for such DCI transmission (e.g., for PRACH resource adaptation) may be configured by the serving RAN independently. In some implementation, the search space for such DCI transmission (e.g., for PRACH resource adaptation) may be shared with DCIs for other purposes.

[0083] In some implementations, the additional PRACH resource configuration may indicate at least one of a first additional PRACH resource for a CFRA procedure or a second additional PRACH resource for a CBRA procedure. The UE may receive, from the serving cell, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource. In some implementations, the first indication may be carried by a paging DCI with CRC scrambled by a P-RNTI. In some implementations, the first indication may be carried by a MAC CE.

[0084] In some implementations, the UE may perform the CBRA procedure with the serving cell on a target PRACH resource associated with the second additional PRACH resource that is activated by the first indication, in response to determining that the CBRA procedure is triggered for a feature included in the additional PRACH resource configuration associated with the second additional PRACH resource.

[0085] Common or Different Configurations

[0086] In some implementations, the baseline PRACH configuration and the additional PRACH configuration may include, or may be present in, any combination of the following PRACH resource configurations:

[0087] - RACH-ConfigCommon;

[0088] - RACH-ConfigDedicated;

[0089] - RACH-ConfigCommonTwoStepRA;

[0090] - RACH-ConfigGeneric;

[0091] - RACH-ConfigGenericTwoStepRA;

[0092] - RACH-ConfigTwoTA;

[0093] - RA-Prioritization; and

[0094] - RA-PrioritizationForSlicing.

[0095] In some implementations, the baseline PRACH configuration may share or reuse the same PRACH configurations and / or parameters (e.g., in the PRACH configurations provided above) with the additional PRACH configuration. In some implementations, the baseline PRACH configuration may be provided with different / independent configurations and / or parameters from those of the additional PRACH configuration.

[0096] RACH-ConfigDedicated

[0097] In some implementations, the additional PRACH configuration may be provided to a UE via the RACH-ConfigDedicated configuration. In some implementations, the additional PRACH resource configuration may further include “rach-ConfigDedicated”, which indicates the Msg1 repetition number to the UE.

[0098] Parameter Sharing or Reuse

[0099] In some implementations, the baseline PRACH resource configuration and the additional PRACH resource configuration may be present in, but not be limited to, an uplink BWP configuration, such as the BWP-UplinkCommon described in the 3GPP TS 38.331 V18.2.0.

[0100] In some implementations, the baseline PRACH resource configuration and the additional PRACH resource configuration may share / reuse any combination of the following parameters. Description of these parameters may be found in the 3GPP TS 38.331 V18.2.0, TS 38.321 V18.2.0, TS 38.213 V18.3.0, and TS 38.214 V18.3.0.

[0101] - Generic parameters, which may be associated with one UL BWP;

[0102] - featureCombinationPreamblesList;

[0103] - messagePowerOffsetGroupB;

[0104] - msg1-SubcarrierSpacing;

[0105] - msg3-transformPrecoder;

[0106] - numberOfRA-PreamblesGroupA;

[0107] - prach-RootSequenceIndex;

[0108] - ra-ContentionResolutionTimer;

[0109] - ra-Msg3SizeGroupA;

[0110] - ra-Prioritization;

[0111] - ra-PrioritizationForAI;

[0112] - ra-PrioritizationForSlicing;

[0113] - rach-ConfigGeneric;

[0114] - restrictedSetConfig;

[0115] - rsrp-ThresholdSSB;

[0116] - ssb-perRACH-OccasionAndCB-PreamblesPerSS; and

[0117] - totalNumberOfRA-Preambles.

[0118] In some implementations, the baseline PRACH resource configuration and the additional PRACH resource configuration may be configured with different / independent parameters or different / independent values on PRACH resource configurations.

[0119] In some implementations, the serving RAN may configure one or more independent parameters for the additional PRACH resource configuration. However, if certain parameters are not explicitly provided in the additional PRACH resource configuration received by the UE, the serving RAN or the UE may reuse the corresponding parameters from the baseline PRACH resource configuration.

[0120] Normal Uplink (NUL) Carrier or Supplementary Uplink (SUL) Carrier

[0121] In some implementations, the additional PRACH resource and the baseline PRACH resource may be configured only on one specific carrier (e.g., NUL carrier / SUL carrier). In other words, only one UL carrier may be configured / activated for the baseline / additional PRACH resource allocation.

[0122] In some implementations, the serving RAN may not support a configuration in which one type of PRACH resource configuration (e.g., baseline or additional) is provided exclusively on one UL carrier (e.g., an NUL carrier), while the other type of PRACH resource configuration (e.g., additional or baseline) is provided exclusively on a different UL carrier.

[0123] In some implementations, the UE may be configured with one type of PRACH resource configuration (e.g., baseline or additional) on one UL carrier (e.g., SUL or NUL) and the other type of PRACH resource configuration (e.g., additional or baseline) on a different UL carrier (e.g., NUL or SUL).

[0124] BWP Implementations

[0125] In some implementations, the baseline PRACH resource configuration may be configured on one or more UL-BWPs (e.g., UL-BWP#1, UL-BWP#2, UL-BWP#3) via the IE rach-ConfigCommon when the UE is configured with four UL-BWPs (e.g., UL-BWP#1 / 2 / 3 / 4) in one frequency carrier.

[0126] In some implementations, the additional PRACH resource may be configured with the baseline PRACH resource in a common UL-BWP (e.g., UL-BWP#1). In some implementations, the additional PRACH resource may be configured in a UL-BWP in which no baseline PRACH resource is configured (e.g., UL-BWP#4).

[0127] In some implementations, the UE may switch its operating UL-BWP (e.g., from UL-BWP#1 to UL-BWP#4) when the UE determines to access, or is instructed by the serving RAN to access, the additional PRACH resource (e.g., configured in UL-BWP#4). In some implementations, such a UL-BWP switching procedure may occur during a transition between a cell DRX non-active duration and a cell DRX active duration, or vice versa.

[0128] Impact on RRC Entity / MAC Entity

[0129] In some implementations, the serving RAN may indicate to the MAC entity of the UE that one or more additional PRACH resources are activated / deactivated. The MAC entity of the UE may receive the additional PRACH resource configuration from the RRC entity of the UE. The UE may receive lower layer signaling (e.g., MAC CE / DCI) indicating that the one or more additional PRACH resources are activated / deactivated.

[0130] In some implementations, the MAC entity of the UE may receive indication / configuration indicating that the one or more additional PRACH resource configurations are activated / deactivated from the RRC entity of the UE. In some implementations, the MAC entity may further receive a default state of the additional PRACH resource configuration.

[0131] The MAC entity may be associated with a master cell group (MCG) or a secondary cell group (SCG).

[0132] In some implementations, different MAC entities may receive different baseline PRACH resource configurations and / or different additional PRACH resource configurations. In addition, a default state (e.g., activated, deactivated, or muted) may be associated with all or a subset of the additional PRACH resources. In some implementations, the default state may be associated with one MAC entity / UL-BWP / PRACH resource configuration.

[0133] The RRC configuration may be transmitted via one or more RRCSetup / RRCResume / RRCReestablishment / RRCRelase / RRCReconfiguration messages. The RRC configuration may be received by the UE via SRB1 / SRB3.

[0134] In some implementations, the UE may store the additional PRACH resource configuration as part of a UE context (e.g., a UE inactive context) upon transitioning from the RRC Connected state to the RRC Inactive state, for example, when the additional PRACH resource configuration is provided via UE-specific control signaling. The UE may resume the stored additional PRACH resource configuration upon / after the UE transitions from the RRC Inactive state to the RRC Connected state.

[0135] In some implementations, the additional PRACH resource configuration may be associated with an accessible / applicable area. Information of the accessible / applicable area may include at least one of the followings: a PCI list, systeminformationareaID(s), tracking area ID(s), and GNSS location coordinates. The UE may keep / store / access the additional PRACH resources while staying within the accessible / applicable area. The UE may release / remove the additional PRACH resource configuration upon leaving the accessible / applicable area.

[0136] In some implementations, the serving RAN may configure / activate / deactivate / mute / unmute one or all of the additional PRACH resources via broadcasting system information (e.g., SIB1 / SIB2 / SIB3 / SIB4 / SIB5 or other SI).

[0137] In some implementations, each MAC entity of the UE may activate / deactivate / mute the additional PRACH resource independently. For example, a MAC entity may receive one or more MAC CE / DCI from a serving cell managed by the MAC entity. Then, the MAC CE / DCI may activate / deactivate / mute / unmute one, some, or all additional PRACH resources associated with the MAC entity.

[0138] Therefore, a MAC entity of the UE may evaluate / consider an additional PRACH resource as available / accessible / applicable upon receiving the configuration from the RRC entity and a MAC CE / DCI that activates the additional PRACH resources.

[0139] Dynamic PRACH Adaptation (e.g., via L1 / L2 message) to Derive the Additional PRACH Resource

[0140] In some implementations, the UE may be configured with a PRACH periodicity list. Each component in the PRACH periodicity list may be implicitly / explicitly associated with an index.

[0141] In some implementations, the serving RAN may transmit a Layer-1 / Layer-2 signaling (e.g., MAC CE or DCI) that may include an index value. The index value transmitted by the MAC CE / DCI may be associated with a PRACH periodicity included in the given PRACH periodicity list (e.g., based on the index value mapping).

[0142] After receiving the MAC CE / DCI, the UE may derive an additional PRACH resource configuration based on the PRACH periodicity indicated by the received MAC CE / DCI.

[0143] In some implementations, there may be one or more PRACH parameter lists for dynamic PRACH adaptation configured to the UE, where each list may include one or more values configured for a PRACH parameter (e.g., prach-ConfigurationIndex or PRACH periodicity). Table 1 below illustrates multiple values configured for the parameter prach-ConfigurationIndex, according to an example implementation of the present disclosure.

[0144] The parameter prach-ConfigurationIndex may be mapped to the table of PRACH parameters specified in the 3GPP TS 38.212 V18.3.0. In some implementations, the index in the Table may be configured explicitly in the configuration or be derived by the UE implicitly (e.g., by the ascending / descending order in the configuration).

[0145] In some implementations, the PRACH parameters configured for dynamic PRACH adaptation may include: SSB burst sets configuration, ssb-perRACH-OccasionAndCB-PreamblesPerSSB, and ra-ContentionResolutionTimer.

[0146] A specific combination may be further associated with one or more indexes at the UE side. The UE may receive one or more indexes in one MAC CE / DCI, where each index may be associated with one value in a given PRACH parameter list. The UE may derive the additional PRACH resource configuration by jointly considering one or more indexes in one MAC CE / DCI.

[0147] In some implementations, the UE may be configured with multiple PRACH configurations (e.g., based on RACH-configGeneric defined in the 3GPP specification), where each PRACH configuration may be associated with an index (e.g., prach-ConfigurationIndex). The serving RAN may indicate which PRACH configuration that the UE should activate by transmitting (e.g., part of) the prach-ConfigurationIndex in a Layer-1 / Layer-2 signaling (e.g., DCI / MAC CE).

[0148] In some implementations, there may be only one active PRACH resource configuration in time domain. The UE may derive / adjust a new PRACH resource based on the RRC configurations and the received DCI / MAC CE(s).

[0149] In some implementations, a set of PRACH parameter lists / PRACH configurations may be common to multiple cell groups. For example, a common or shared configuration may be applied across the MCG and SCG by the RRC entity on the UE and / or RAN side. The serving RAN may transmit different MAC CEs and / or DCIs to the UE to derive different additional PRACH resource configurations for the MCG and SCG, respectively. Accordingly, the MAC entity of a cell group (e.g., MCG or SCG) may derive the additional PRACH resources for its managed cell group by considering the Layer-1 / Layer-2 control signaling (e.g., MAC CE or DCI) received from serving cells also managed by that MAC entity. In other words, the serving RAN may not adjust the additional PRACH resource configuration for the MCG by transmitting signaling to serving cells belonging to the SCG, and vice versa. On the UE side, the MAC CE or DCI received from one cell group may only affect the additional PRACH resource configuration associated with that cell group. That is, the configuration for one cell group may not be influenced by signaling received from serving cells of another cell group.

[0150] DCI Format for Baseline / Additional PRACH Resource Indication (e.g., to Support LTM Operation)

[0151] In some implementations, the disclosed DCI for baseline / additional PRACH resource indication may be applicable to DCI format 1_0 and DCI format 0_1. However, the applicability is not limited to these DCI formats and may also extend to other DCI formats.

[0152] The DCI format may include a PRACH retransmission indicator, which may be 0 or 1 bit. This field may be 1 bit if the UE is configured with higher layer parameter EarlyUlSyncConfig. This field indicates initial transmission or retransmission of PRACH (e.g., according to Table 7.3.1.2.1-3 in the 3GPP TS 38.212 V18.3.0) if the cell indicated by Cell indicator field is a candidate cell, and this field is reserved if the cell indicated by Cell indicator field is a serving cell but not a candidate cell.

[0153] In some implementations, both the initial transmission and retransmission may be required to be transmitted in the same type of PRACH resource (e.g., either the baseline PRACH resource or additional PRACH resource). This requirement may be due to differences in the PHY parameters between the baseline and additional PRACH resources, which may result in the UE being capable of accessing only one type of PRACH resource for both the initial transmission and the retransmission.

[0154] In some implementations, the initial transmission and retransmission may be transmitted by the UE via either the baseline PRACH resource or the additional PRACH resource, no matter whether the PHY parameters of the baseline PRACH resource and the additional PRACH resource are the same or not.

[0155] In some implementations, the UE may determine the type of PRACH resource to be used for an initial transmission and / or retransmissions (e.g., a preamble transmission and / or preamble retransmissions).

[0156] In some implementations, the DCI may indicate the type of PRACH resource (e.g., the baseline or additional PRACH resource configuration) to be used by the UE for preamble transmission.

[0157] Preamble / MSG1 Repetition

[0158] In some implementations, a UL BWP may be configured with one or more DL-RSRP thresholds that the UE may use to determine whether to select resources associated with specific numbers of MSG1 repetitions (e.g., 2, 4, or 8 repetitions) in the UL BWP.

[0159] In some implementations, the UE may use the following thresholds, including rsrp-ThresholdMsg1-RepetitionNum2, rsrp-ThresholdMsg1-RepetitionNum4, and rsrp-ThresholdMsg1-RepetitionNum8, to determine whether to select resources indicating MSG1 repetition numbers of 2, 4, or 8, respectively, in the UL BWP.

[0160] In some implementations, the UE may assume that Msg1 repetition is applicable for the current random access procedure if the BWP selected for random access procedure is configured only with random access resources for which the msg1-Repetitions parameter is set to true.

[0161] In some implementations, the configured threshold values may apply to all UL BWPs and all RACH configurations (e.g., both baseline PRACH configuration and additional PRACH configuration). This configured threshold value field for MSG1 repetition on one specific random access resources, which supports MSG repetition, may be mandatory when multiple sets of random access resources are configured in the BWP, where some sets are configured with MSG1 repetition indication and others are not, or when all sets are configured with MSG1 repetition indication but are associated with different repetition numbers in the BWP. Otherwise, the field may be absent on one specific random access resources if the random access resources does not support MSG1 repetition. In addition, the configured threshold values may apply to all of the configured additional PRACH resource configurations for an NES-capable UE.

[0162] In some implementations, different sets of thresholds may be configured to baseline PRACH resource configuration and additional PRACH resource configuration respectively. For example, the original thresholds {rsrp-ThresholdMsg1-RepetitionNum2, rsrp-ThresholdMsg1-RepetitionNum4, rsrp-ThresholdMsg1-RepetitionNum8} may be configured to be associated with the baseline PRACH resource configuration (for NES-capable / non-NES-capable UEs). Another set of thresholds {rsrp-ThresholdMsg1-RepetitionNum2_Add, rsrp-ThresholdMsg1-RepetitionNum4_Add, rsrp-ThresholdMsg1-RepetitionNum8_Add} may be configured to be associated with the additional PRACH resource configuration.

[0163] In some implementations, if the initial / first preamble is transmitted on the baseline PRACH resource, the UE may perform the repeated preamble transmissions only on the baseline PRACH resource. Similarly, if the initial / first preamble is transmitted on the additional PRACH resource, the repeated preamble transmissions may be limited to the additional PRACH resource. In some implementations, the UE may transmit the initial and repeated preambles across both the baseline and additional PRACH resources, regardless of which resource was used for the initial / first preamble transmission.

[0164] MSG3 Repetition

[0165] In some implementations, the UE may first determine whether msg3-Repetitions are applicable to any of baseline PRACH resource / additional PRACH resource configuration. For example, this determination may be based on whether the msg3-Repetitions is set to true and whether the DL RSRP of the downlink pathloss reference is below the rsrp-ThresholdMsg3.

[0166] In some implementations, the same msg3-Repetitions and rsrp-ThresholdMsg3 settings may be configured for both the baseline PRACH resource configuration and the additional PRACH resource configuration. In some implementations, separate msg3-Repetitions and rsrp-ThresholdMsg3 settings may be individually configured for the baseline PRACH resource configuration and the additional PRACH resource configuration.

[0167] On-Demand SI Request Procedure

[0168] In some implementations, the PRACH resource configured / provided for an on-demand system information (SI) request procedure may only be supported / configured on the baseline PRACH resource configuration. In other words, no PRACH resource configuration for on-demand may be supported / configured on the additional PRACH resource configuration (e.g., for network energy saving).

[0169] In some implementations, the PRACH resource for the on-demand SI request procedure may be configured on the baseline PRACH resource configuration and / or the additional PRACH resource configuration.

[0170] Enhanced Cell DRX

[0171] For the cell DRX operation, the present disclosure describes issues related to accessibility / mute on cell DRX non-active / active duration, parameter adaptation on cell DRX non-active / active duration, and DCI instruction to change parameter before a cell DRX non-active duration. The active duration may also be referred to as active time. The non-active duration may also be referred to as inactive time.

[0172] In some implementations, additional / baseline PRACH resource may not be valid / accessible (e.g., to an NES-capable UE and / or a non-NES-capable UE) during the cell DRX non-active duration. In some implementations, the additional PRACH resource configuration may be valid only in the cell DRX active duration.

[0173] In some implementations, when the serving cell operates in a cell DRX mode, availability of the baseline PRACH resource may depend on the cell DRX mode, and availability of the additional PRACH resource may be independent of the cell DRX mode. In some implementations, when the serving cell operates in a cell DRX mode, the UE may not be allowed to transmit on the baseline PRACH resource during cell DRX inactive time, and the UE may be allowed to transmit on the additional PRACH resource during the cell DRX inactive time.

[0174] In some implementations, the technical specification may define that the additional PRACH resource configuration may not be valid / accessible (e.g., to an NES-capable UE and / or a non-NES-capable UE) in the cell DRX non-active duration. In some implementations, the technical specification may define that the additional PRACH resource configuration may be valid only in the cell DRX active duration.

[0175] In some implementations, the serving RAN may configure the UE to indicate that the additional PRACH resource is applicable or valid during the cell DRX non-active duration (e.g., via RRC signaling). For example, an information element (e.g., Additional_PRACH_DRX) may be set to “true”, ‘1’, or “accessible” to indicate that the additional PRACH resource is accessible to the UE. In contrast, the information element (e.g., Additional_PRACH_DRX) may be set to “false”, ‘0’, or “not accessible” to indicate that the additional PRACH resource is not accessible during the DRX non-active duration.

[0176] In some implementations, a dynamic control signaling (e.g., a DCI or MAC CE) may be configured / transmitted by the serving RAN to inform the UE whether the additional PRACH resource is valid / accessible or not.

[0177] In some implementations, a specific search space for the dynamic DCI indicating whether the additional PRACH resource is valid / accessible or not may be pre-configured to the UE (e.g., an NES-capable UE) via RRC signaling. In some implementations, the DCI indicating whether the additional PRACH resource is valid / accessible or not may be transmitted in a search space shared with DCIs of other DCI formats.

[0178] In some implementations, the DCI indicating whether the additional PRACH resource is valid / accessible or not may be the same DCI that includes other information, such as: (A) a DCI that instructs the UE to transmit a preamble for UE uplink timing acquisition; or (B) a DCI that instructs the UE to transmit a preamble for UE uplink timing acquisition, which may be associated with an LTM candidate, during an LTM operation. This mechanism may also be applicable to (conditional) LTM operations.

[0179] In some implementations, the UE may receive DCI that instructs a PRACH resource transmission. In this condition, the UE may be enabled / authorized to transmit a preamble on the indicated baseline / additional PRACH resource configuration even if the selected PRACH resource may be located on the cell DRX non-active duration.

[0180] In some implementations, the UE may receive DCI(s) to initiate a PRACH transmission on the PRACH resources of another cell (e.g., an LTM candidate). In this condition, the UE may ignore the cell DRX operation associated with the serving cell and initiate the PRACH transmission associated with the LTM candidate indicated by the received DCI.

[0181] In some implementations, different PRACH configurations (e.g., prach-ConfigurationIndex) may be applied to the cell DRX active duration and the cell DRX non-active duration respectively. In some implementations, the applicable PRACH configuration (e.g., applicable PRACH configuration applied in cell DRX active duration / cell DRX non-active duration) may be pre-configured by the serving RAN via broadcasting system information or via SI on-demand procedure. In some implementations, the applicable PRACH configuration (e.g., applicable PRACH configuration applied in cell DRX active duration / cell DRX non-active duration) may be dynamically indicated / adapted by the serving RAN via dynamic signaling (e.g., MAC CE / DCI / Wake-Up-Signal).

[0182] In some implementations, a wake-up signaling (WUS) may be configured to the UE to indicate whether PRACH transmission is accessible in a given DRX non-active duration. The WUS may be transmitted by the serving RAN on a DRX active duration (e.g., the DRX active duration earlier than the concerned DRX non-active duration) or in the beginning of the concerned DRX non-active duration.

[0183] In some implementations, the UE may access the baseline / additional PRACH resource that is entirely accessible in time domain / physical resource block domain. For example, the UE may access a PRACH resource that is not truncated / affected by transitions between the cell DRX active durations and cell DRX non-active durations. In other words, the UE may not access the baseline / additional PRACH resource of which the accessibility is partially influenced by the cell DRX active / non-active durations.

[0184] In some implementations, the UE may still be able to access the baseline / additional PRACH resource even if part or a subset of the concerned PRACH resource is influenced by transitions between the cell DRX active durations and cell DRX non-active durations.

[0185] FIG. 2 is a timing diagram 200 illustrating a dynamic PRACH adaptation related to a cell DRX operation, according to an example implementation of the present disclosure. In some implementations, a PRACH configuration may indicate a baseline PRACH resource and an additional PRACH resource. As illustrated in FIG. 2, there may be first resource blocks 202 corresponding to a baseline PRACH resource, a second resource block 204 corresponding to an additional PRACH resource, and a third resource block 208 corresponding to an L1 / L2 message for dynamic PRACH adaptation.

[0186] The L1 message (e.g., a UE-specific DCI or group-common DCI) or L2 message corresponding to the third resource block 208 may indicate PRACH parameters or an index associated with the PRACH parameters of the baseline / additional PRACH configuration during the cell DRX non-active duration. As illustrated in FIG. 2, in the cell DRX non-active duration, there may be fourth resource blocks 212 corresponding to an empty baseline PRACH resource, and a fifth resource block 214 corresponding to an empty / skipped additional PRACH resource. The term “empty” and “skipped” baseline / additional PRACH resource may refer to a PRACH resource on which the UE refrains from performing uplink transmission. In some implementations, the dynamic adaptation of the additional / baseline PRACH configuration may be valid across several cell DRX non-active durations. In some implementations, the dynamic adaptation may be kept valid until the UE receives another L1 / L2 message for dynamic PRACH adaptation.

[0187] Impact on Conventional / Conditional LTM Operation

[0188] If the UE is configured with LTM candidate cells, there may be zero or one RACH for each LTM candidate cell, which may share the same corresponding MAC entity with the serving cell.

[0189] In some implementations, the UE may be instructed by the serving RAN (e.g., via PDCCH order) to transmit a preamble for UL timing acquisition during an LTM operation. In this condition, the UE may transmit a preamble on a configured PRACH resource. In addition, the PRACH resource may be the additional PRACH resource or the baseline PRACH resource.

[0190] In some implementations, the PDCCH order may indicate an LTM candidate and an SSB. In some implementations, both baseline SSB configuration and additional SSB configuration (e.g., the additional SSB configuration for network energy saving) may also be applied to the mapping of the additional PRACH resource configuration.

[0191] PRACH Resource Configuration Associated with Additional PCI

[0192] In some implementations, the serving RAN may configure a list of PRACH configurations associated with additional PCIs. Table 2 below illustrates a list of additional PRACH configurations, according to an example implementation of the present disclosure.

[0193] There may be an IE additionalRACH-perPCI-ToAddModList in the related RRC configuration, as specified in the 3GPP TS 38.331 V18.2.0. The IE additionalRACH-perPCI-ToAddModList may indicate a list of RACH configurations for the additional PCIs. The PRACH configuration for an additional PCI may be applied for a random access procedure initiated by the PDCCH order towards to the additional PCI, as specified in the 3GPP TS 38.321 V18.2.0. This configuration may be different for different UEs.

[0194] In some implementations, the PRACH configuration for an additional PCI may also include the baseline PRACH resource configuration and the additional PRACCH resource configuration. In some implementations, only the baseline PRACH configuration may be applicable to the PRACH resource configuration for additional PCI.

[0195] UE-based TA Acquisition

[0196] In some implementations, the serving RAN may indicate which PRACH resource to be applied by the UE when the UE-based TA measurement is configured by the serving RAN. In some implementations, the UE may receive DCI that instructs the UE to perform a CFRA procedure towards an indicated candidate LTM cell.

[0197] In some implementations, the serving RAN may pre-configure the UE (e.g., an NES-capable UE) with both the baseline PRACH resource and the additional PRACH resource associated with one or more LTM candidates. The baseline PRACH resource (configuration) and / or the additional PRACH resource (configuration) may be pre-configured as part of a reference configuration.

[0198] In some implementations, the baseline PRACH resource configuration may be provided in the reference configuration and the additional PRACH configuration may be (optionally) configured in an LTM candidate configuration. In some implementations, the additional PRACH resource configuration may also be provided in the reference configuration.

[0199] In some implementations, an LTM candidate may be associated only with the baseline PRACH resource configuration and another LTM candidate may be associated with both the baseline PRACH resource configuration and the additional PRACH resource configuration.

[0200] In some other implementations, the serving RAN may pre-configure only the baseline PRACH resource (configuration) to a legacy / non-NES capable UE.

[0201] In some implementations, the LTM candidate may operate in a cell DTX / cell DRX mode for network energy saving.

[0202] Baseline / Additional PRACH Selection Indicated / Configured by RAN

[0203] In some implementations, the serving RAN may transmit a DCI to instruct a UE to initiate a CFRA procedure for UE timing acquisition. In addition, the serving RAN may further indicate which PRACH resource that the UE should apply for the CFRA procedure by providing additional information in the DCI. For example, one or more bits in the DCI may be pre-defined to be associated with the baseline PRACH resource configuration, while one or more other bits in the DCI may be associated with the additional PRACH resource configuration. In each DCI transmission, the serving RAN may instruct the UE which type of PRACH resource that the UE should access for the initiated CFPA procedure.

[0204] In some implementations, the serving RAN may transmit a MAC CE (e.g., an LTM CSC MAC CE) to instruct the UE to initiate an LTM procedure.

[0205] In addition, the serving RAN may further indicate which PRACH resource that the UE should apply for the LTM cell switch operation if a random access procedure is to be initiated by the UE during the LTM cell switch operation. For example, one or more fields in the LTM CSC MAC CE may be pre-defined to be associated with the baseline PRACH resource configuration, while one or more other fields in the LTM CSC MAC CE may be associated with the additional PRACH resource configuration. In each MAC CE transmission, the serving RAN may instruct the UE which type of PRACH resource (e.g., baseline PRACH resource and / or additional PRACH resource) that the UE should access for the initiated CFPA procedure.

[0206] Baseline / Additional PRACH Selected by UE

[0207] In some implementations, the UE may determine which PRACH resource that the UE should access for preamble transmission / UE-based TA acquisition by the UE itself. For example, this determination may be based on the earliest available PRACH resource (e.g., available in time domain / frequency domain / physical resource domain).

[0208] Impact on LTM Operation while Additional PRACH Resource and Cell DRX are Considered

[0209] In some implementations, the additional PRACH resource configuration may not be available / accessible during the cell DRX non-active duration, while the baseline PRACH resource configuration may be available / accessible during the cell DRX non-active duration and cell DRX active duration. The UE (e.g., an NES-capable UE) may be able to access both the baseline and additional PRACH resources when selecting an available PRACH resource outside of the cell DRX non-active duration. The UE may only access the baseline PRACH resource configuration when selecting an available PRACH resource during the cell DRX non-active duration.

[0210] RRC Re-establishment Procedure (e.g., while the timer T311 is running)

[0211] In some implementations, the UE may be allowed / enabled by the serving RAN to perform an LTM operation while the timer T311 is running.

[0212] In some implementations, the UE may also be enabled to access the additional PRACH resource for the LTM operation when the UE is configured with {attemptLTM-Switch = true}. In some implementations, the UE may select a PRACH resource that is entirely accessible to the UE during the RA procedure / PRACH transmission.

[0213] Power Ramping during PDCCH Order PRACH Transmission

[0214] In some implementations, the UE may increase the power ramping factor to the PRACH transmission on the LTM candidate cell if the DCI indicates a retransmission (e.g., retransmission of the initial transmission) to the same LTM candidate.

[0215] In some implementations, the UE may receive a first DCI associated with an SSB#1 of LTM candidate#1 for PDCCH order PRACH transmission during an LTM procedure. Then, the UE may receive a second DCI associated with another SSB#2 of LTM candidate#1 for PDCCH order PRACH transmission. The SSB#1 may be the baseline SSB configuration that is accessible to both the NES-capable UE and the non-NES-capable UE. The SSB#2 may be the additional SSB configuration that is accessible only to the non-NES-capable UE.

[0216] Overlapping Condition

[0217] In some implementations, the baseline PRACH resource and the additional PRACH resource may overlap in time domain / frequency domain / PRBs.

[0218] In some implementations, when the UE (e.g., the NES-capable UE that is able access the additional PRACH resource) initiates a random access procedure (e.g., a RACH transmission triggered by PDCCH order), the UE may prioritize the additional PRACH resource for preamble transmission. In some implementations, the UE may be enabled / authorized to determine which type of PRACH resource (e.g., additional PRACH resource / baseline PRACH resource) may be prioritized when the overlapping condition occurs.

[0219] In some implementations, the disclosed rule for the decision of PRACH resource regarding the overlapping issue may be applied one time and the decision may be valid for initial transmission / re-transmission / repetition during an RA procedure / PRACH transmission. In some implementations, the disclosed rule for the decision for the overlapping issue may be applied by the UE to every initial transmission / retransmission / repetition.

[0220] Additional Configuration to Avoid Overlapping between Baseline and Additional PRACH Resources

[0221] In some implementations, the UE may be configured with timing parameters for the additional PRACH configuration. The timing parameters may include at least one of the following: scaled / adjusted PRACH configuration period, additional timing offset, adjusted parameters (e.g., (x, y) value and slot number) of the PRACH configuration, and muting / masking ROs.

[0222] In some implementations, one or more options may be configured to be associated with the additional PRACH resource configuration. For example, a list of scaled / adjusted PRACH configuration periods may be configured to the UE. A list of additional timing offsets may be configured to the UE. A list of parameters (e.g., (x, y) value and slot number) may be configured to the UE. A list of muting / masking ROs patterns may be configured to the UE.

[0223] The serving RAN may indicate which timing parameters to be applied by transmitting a Layer-1 signaling (e.g., a UE-specific DCI or a group-common DCI) or a Layer-2 signaling (e.g., a MACE CE) to the UE. The DCI / MAC CE may include an index to be mapped to a value in the list (e.g., based on the ascending order / descending order in the list). In some implementations, the DCI / MAC CE may further indicate which option (e.g., which timing parameter) or which list associated with the option that the UE should apply for the timing parameter decision / configuration.

[0224] In some implementations, when the serving RAN operates in a cell DRX mode, the serving RAN may indicate which timing parameters to be applied within one or more cell DRX non-active durations. In some implementations, the serving RAN may transmit a DCI (e.g., using DCI format 2_7 as a template), a MAC CE, or a WUS either before the end of a cell DRX active duration or at the beginning of a cell DRX non-active duration to indicate the timing parameters applied for the additional PRACH resource configuration in the subsequent cell DRX non-active duration.

[0225] Switch between NES-Capable and Non-NES-Capable, and Other Features

[0226] In some implementations, the UE may switch its operating mode between NES-Capable and Non-NES-Capable. The UE may determine which mechanisms that the UE uses based on its current operating mode.

[0227] The UE may release / reset / remove / restart the disclosed mechanism when the UE changes its operating mode, such as upon transitioning from NES-capable to non-NES-capable, or vice versa.

[0228] In some implementations, the disclosed mechanisms may also be applicable to UEs embedded with other features. For example, the UE may be a RedCap UE as defined in the 3GPP specifications.

[0229] PRACH Resource Configurations for One or More Features

[0230] The IE FeatureCombination may indicate a feature or a combination of features to be associated with a set of random access resources (e.g., an instance of FeatureCombinationPreambles). Table 3 below illustrates an ASN.1 representation of the IE FeatureCombination, according to an example implementation of the present disclosure.

[0231] In some implementations, a unified FeatureCombination may be applicable to both the baseline and additional PRACH resource configurations. In some implementations, the baseline and additional PRACH resource configurations may be configured by the serving RAN to be associated with different FeatureCombinations, respectively.

[0232] In some implementations, the UE may be configured with PRACH / preamble resources for one or more features.

[0233] As illustrated in Table 2, there may be an IE additionalRACH-ConfigList, which may indicate a list of feature or feature combination-specific RACH configurations, such as the RACH configurations configured in addition to the one configured by the rach-ConfigCommon(s) (which may be baseline PRACH resource configuration and / or additional PRACH resource configuration) and by msgA-ConfigCommon(s) (which may be baseline PRACH resource configuration and / or additional PRACH resource configuration). The network may associate all possible preambles of an additional RACH configuration with one or more features or feature combinations. The network may not configure this list to have more than 32 entries. If both rach-ConfigCommon and msgA-ConfigCommon are configured for a specific FeatureCombination, the network may provide them in the same additionalRACH-Config.

[0234] In some implementations, the network energy saving may also be designed / indicated as one of the features. The disclosed additional PRACH resource configuration may be provided by the serving cell as an additional IE including rach-ConfigCommon and / or msgA-ConfigCommon.

[0235] In some implementations, the PRACH configuration in the additionalRACH-configList may also be divided into baseline PRACH resource configuration and additional PRACH resource configuration associated with network energy saving.

[0236] The configuration may be provided to the UE via broadcasting system information (e.g., SIB2 or a new system information block) or UE-specific control signaling.

[0237] PRACH Resource Configurations for one or more features (Priority / Preamble Assignment)

[0238] In some implementations, the UE may be configured with priorities for one or more specific features (e.g., by referring to the featurePriorities-r17 and featurePriorities-v1800 in the 3GPP TS 38.331 V18.2.0). Table 4 below illustrates the IE featurePriorities-r17 and the IE featurePriorities-v1800, according to an example implementation of the present disclosure.

[0239] The IE featurePriorities-r17 and the IE featurePriorities-v1800 may indicate priorities for features, such as RedCap, eRedCap, Slicing, SDT, Msg1-Repetitions and Msg3-Repetitions for coverage enhancements. These priorities may be used to determine which FeatureCombinationPreambles the UE may use when a feature maps to more than one FeatureCombinationPreambles, as specified in the 3GPP TS 38.321 V18.2.0. A lower value may mean a higher priority. The network may not signal the same priority for more than one feature. The network may signal a priority for all features that map to at least one FeatureCombinationPreambles.

[0240] The IE FeatureCombinationPreambles may associate a set of preambles with a feature combination. For parameters that may be provided in this IE, the UE may apply this field value when performing random access using a preamble in this featureCombinationPreambles, otherwise the UE may apply the corresponding value as determined by applicable Need Code (e.g., Need S). On a specific BWP, there may be at most one set of preambles associated with a given feature combination per RA Type (e.g., 4-step RACH or 2-step RACH) per Msg1 repetition number. Table 5 below illustrates an ASN.1 representation of the IE FeatureCombinationPreambles, according to an example implementation of the present disclosure.

[0241] In some implementations, a unified FeatureCombinationPreambles may be applicable to both baseline PRACH resource and additional PRACH resource when an NES-capable UE initiates / re-starts / continues a random access procedure. In some implementations, the unified FeatureCombinationPreambles may be applicable to the baseline / additional PRACH resource on the same UL-BWP. In some implementations, different FeatureCombinationPreambles may be applicable to the baseline / additional PRACH resource on different UL BWPs respectively.

[0242] In some implementations, different FeatureCombinationPreambles configurations may be configured to the baseline PRACH resource and the additional PRACH resource respectively.

[0243] In some implementations, the additional PRACH resource configuration and the baseline PRACH resource configuration may differ in at least one of the following parameters: a threshold for a DL-RSRP, a numerology, a periodicity, a BWP, an uplink carrier, an association with SSBs, multiple features, or multiple feature priorities corresponding to the features.

[0244] The FeatureCombinationPreambles configuration may include at least one of the following parameters: {startPreambleForThisPartition, numberOfPreamblesPerSSB-ForThisPartition, ssb-SharedRO-MaskIndex, and numberOfRA-PreamblesGroupA} to indicate the range of preambles applicable to different features.

[0245] Table 6 below illustrates a portion of a random access response procedure, according to an example implementation of the present disclosure. This procedure utilizes the parameters described above. A detailed description of the random access response procedure may be found in the 3GPP TS 38.321 V18.2.0. The random access response procedure may be applicable to the baseline PRACH resource configuration and / or additional PRACH resource configuration. In some additional implementations, the Msg1 repetition number of the (baseline / additional) PRACH resource sets selected by the UE (for one feature or feature combination decided by the UE) may differ and so the UE may select the set of random access resources cross the (baseline / additional) PRACH resource configuration.

[0246] Impact on IAB Operation

[0247] In some implementations, the serving cell may configure the RACH resource configuration to be used by IAB-MT.

[0248] The IE rach-ConfigCommonIAB may be a configuration of cell specific random access parameters for the IAB-MT. The IAB specific IAB RACH configuration may be used by IAB-MT, if configured.

[0249] In some implementations, there may be NES-capable IAB-MT and non-NES-capable IAB-MT.

[0250] The serving RAN may configure the baseline PRACH resource configuration for non-NES-capable IAB-MT / NES-capable IAB-MT and the additional PRACH resource configuration (e.g., for the NES-capable IAB-MT). In addition, the serving RAN may also configure the additional PRACH resource configuration for the NES-capable IAB-MT.

[0251] In some implementations, the rach-ConfigCommonIAB may be configured / supported only in association with the baseline PRACH resource configuration. In some implementations, the rach-ConfigCommonIAB may not be configured / supported in association with the additional PRACH resource configuration.

[0252] In some implementations, the rach-ConfigCommonIAB may be configured to overlap (e.g., partially) with the baseline PRACH resource and / or additional PRACH resource in PRB domain.

[0253] RecCap UE

[0254] In some implementations, the feature of additional PRACH resource configuration may not be supported / applicable to certain UEs. A RedCap UE may not be configured with the additional PRACH resource configuration. The RedCap UE may only be configured with the baseline PRACH resource configuration.

[0255] Tx Power of Baseline / Additional) PRACH Resource

[0256] In some implementations, different transmission power configurations (e.g., for preamble transmission) may be pre-configured to the baseline and additional PRACH resources respectively. In some implementations, the same transmission power may be configured to both the baseline and additional PRACH resources.

[0257] In some implementations, the serving RAN may indicate the Tx power level in a L1 / L2 signal (e.g., MAC CE, DCI) that activates / changes an additional PRACH resource or a set of additional PRACH resources. In some implementations, the UE may be configured with a list of Tx power values, where each Tx power may be explicitly / implicitly associated with a Tx power index. The serving RAN may indicate the Tx power value (e.g., associated with one or more additional PRACH resources) by indicating the Tx power index via a MAC CE / DCI (e.g., the MAC CE / DCI that activates the additional PRACH resource).

[0258] Joint Impact between the SSB adaptation and PRACH adaptation for NES

[0259] In some implementations, the UE may be configured with SSB adaptation for network energy saving. One SSB may be activated / deactivated by the serving RAN (e.g., via RRC signaling, MAC CE, DCI).

[0260] In some implementations, one or more of the PRACH resources associated with the activated SSB(s) may also be activated. In some implementations, one or more of the PRACH resources associated with the deactivated SSB(s) may also be deactivated accordingly.

[0261] Paging-DCI-based Design

[0262] In some implementations, the serving RAN may indicate the dynamic PRACH resource adaptation via transmission of the paging DCI. For example, the serving RAN may transmit a prach-ConfigurationIndex value directly or an index associated with the prach-ConfigurationIndex.

[0263] In some implementations, the serving RAN may further indicate an MO-SDT indication in the same paging DCI. For a UE that is also triggered to initiate a random access procedure for MO-SDT, the UE may prioritize the additional PRACH resource configuration (e.g., based on the given index transmitted on the same DCI) for the random access procedure.

[0264] PEI-related Design

[0265] In some implementations, the serving RAN may indicate the dynamic PRACH resource adaptation via a PEI. For example, the serving RAN may transmit a prach-ConfigurationIndex value directly or an index associated with the prach-ConfigurationIndex. An NES-capable UE in the RRC Connected state may receive / monitor the PEI to decode / obtain the latest dynamic PRACH adaptation for the additional PRACH resource configuration. A non-NES-capable UE in the RRC Connected state may not need to decode the PEI for dynamic PRACH adaptation.

[0266] The RRC Connected UE may determine a subgroup for PEI monitoring based on the subgroup ID configured by the AMF or calculation of the UE_ID as defined in the technical specification.

[0267] In some implementations, a UE in the RRC Connected state may ignore the “lastUsedCellOnly” broadcast in the SIB1 for PEI monitoring (e.g., for the purpose of dynamic adaptation on the additional PRACH resource configuration).

[0268] Summary

[0269] An NES-capable UE may be configured with a baseline PRACH resource configuration and an additional PRACH resource configuration. The serving RAN may further indicate the activation / deactivation / adaptation of the PRACH resource configuration via at least one of the following: broadcasting system information, UE-specific RRC signaling, and DCI.

[0270] In summary, the present description relates to one or more of the following items.

[0271] Item 1. A random access resource decision rules for a user equipment supporting network energy saving, comprising: 　　　　receiving, by the UE, a baseline PRACH resource configuration and an additional PRACH resource configuration from the serving radio access network; 　　　　determining, by the UE, whether and how to access the additional PRACH resource based on one or more indications from the serving RAN.

[0272] Item 2. The method according to item 1, wherein the UE receives the one or more indications via at least one of the following: broadcasting system information, UE-specific RRC signaling, and Layer-1 signaling (e.g., DCI).

[0273] Item 3. The method according to item 1, wherein the one or more indications includes PRACH resource (de)activation / PHY-layer parameter configuration.

[0274] Item 4. The method according to item 3, wherein the one of the received indication is associated with additional PRACH resource configuration on one or more Cell DRX occasions / instances in time domain.

[0275] FIG. 3 is a flowchart illustrating a method / process 300 performed by a UE for performing a random access resource management operation, according to an example implementation of the present disclosure. In the action 302, the process 300 may start by receiving, from a serving cell, a first configuration indicating a baseline PRACH resource. In the action 304, the process 300 may receive, from the serving cell, a second configuration indicating at least one of a first additional PRACH resource for a CFRA procedure or a second additional PRACH resource for a CBRA procedure. In the action 306, the process 300 may receive, from the serving cell, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource. The process 300 may then end.

[0276] The steps / actions shown in FIG. 3 should not be construed as necessarily order dependent. The order in which the process is described is not intended to be construed as a limitation. Moreover, some of the actions shown in FIG. 3 may be omitted in some implementations and one or more actions shown in FIG. 3 may be combined.

[0277] The technical problem addressed by the method illustrated in FIG. 3 is configuring baseline and additional PRACH resources and an indication for activating / deactivating the additional PRACH resource. The method in FIG. 3 provides an explicit indication to activate or deactivate the additional PRACH resources (e.g., for CFRA and / or CBRA), thereby allowing the UE to selectively use only the activated resources. This improves access efficiency, reduces power consumption, and enhances adaptability to varying network conditions. As such, the network can dynamically control the usage of the additional PRACH resources based on real-time conditions (e.g., load balancing, UE state, access priority). The activation / deactivation mechanism also allows the network to efficiently allocate PRACH resources on a per UE basis (e.g., for RedCap UEs and regular UEs).

[0278] In some implementations, the first indication may be carried by a paging DCI with CRC scrambled by a P-RNTI or a MAC CE. The first indication may be referred to as a dynamic activation / deactivation indication, as the serving cell may dynamically activate or deactivate at least one of the first additional PRACH resource or the second additional PRACH resource via the first indication.

[0279] In some implementations, the second configuration may include a second indication for indicating whether the at least one of the first additional PRACH resource or the second additional PRACH resource is activated or deactivated by default. The serving cell may configure a default activation / deactivation state for the at least one of the first additional PRACH resource or the second additional PRACH resource.

[0280] In some implementations, the UE may receive, from the serving cell, a DCI to initiate a PDCCH-order RA procedure on a target PRACH resource associated with one of the first and second additional PRACH resources. The UE may perform the PDCCH-order RA procedure with the serving cell on the target PRACH resource. The PDCCH-order RA procedure may be the CFRA procedure when the target PRACH resource is associated with the first additional PRACH resource. The PDCCH-order RA procedure may be the CBRA procedure when the target PRACH resource is associated with the second additional PRACH resource. The DCI for initiating the PDCCH-order RA procedure may be scrambled by the C-RNTI of the UE. The second configuration may include a PCI of the serving cell. The at least one of the first additional PRACH resource or the second additional PRACH resource may be associated with the PCI of the serving cell. In some implementations, the second configuration may include an IE additionalRACH-perPCI-ToAddModList for indicating a list of RACH configurations (e.g., associated with at least one of the first additional PRACH resource or the second additional PRACH resource) for one or more PCIs (e.g., including the PCI of the serving cell).

[0281] In some implementations, the UE may perform the CBRA procedure with the serving cell on a target PRACH resource associated with the second additional PRACH resource that is activated by the first indication, in response to determining that the CBRA procedure is triggered for a feature included in the second configuration associated with the second additional PRACH resource.

[0282] In some implementations, the first configuration may include a parameter having a first value associated with the baseline PRACH resource, and the second configuration may include the parameter having a second value associated with the first additional PRACH resource or the second additional PRACH resource, where the first value may be different from the second value. The parameter may be one of the following: a threshold for a DL-RSRP, a numerology, a periodicity, a BWP, an uplink carrier, an association with SSBs, multiple features, or multiple feature priorities corresponding to the features.

[0283] In some implementations, the UE may store the second configuration as part of a UE inactive context upon transitioning from the RRC Connected state to the RRC Inactive state. The UE may resume the stored second configuration upon transitioning from the RRC Inactive state to the RRC Connected state.

[0284] FIG. 4 is a flowchart illustrating a method / process 400 performed by a BS for configuring a random access resource, according to an example implementation of the present disclosure. In the action 402, the process 400 may start by transmitting, via a serving cell to a UE, a first configuration indicating a baseline PRACH resource. In the action 404, the process 400 may transmit, via the serving cell to the UE, a second configuration indicating at least one of a first additional PRACH resource for a CFRA procedure or a second additional PRACH resource for a CBRA procedure. In the action 406, the process 400 may transmit, via the serving cell to the UE, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource. The process 400 may then end. The method illustrated in FIG. 4 is similar to that in FIG. 3, except that it is described from the perspective of the BS (instead of the UE).

[0285] FIG. 5 is a block diagram illustrating a node 500 for wireless communication in accordance with various aspects of the present disclosure. As illustrated in FIG. 5, a node 500 may include a transceiver 520, a processor 528, a memory 534, one or more presentation components 538, and at least one antenna 536. The node 500 may also include a radio frequency (RF) spectrum band module, a BS communications module, a network communications module, and a system communications management module, Input / Output (I / O) ports, I / O components, and a power supply (not illustrated in FIG. 5).

[0286] Each of the components may directly or indirectly communicate with each other over one or more buses 540. The node 500 may be a UE or a BS that performs various functions disclosed with reference to FIGS. 1 through 4.

[0287] The transceiver 520 has a transmitter 522 (e.g., transmitting / transmission circuitry) and a receiver 524 (e.g., receiving / reception circuitry) and may be configured to transmit and / or receive time and / or frequency resource partitioning information. The transceiver 520 may be configured to transmit in different types of subframes and slots including, but not limited to, usable, non-usable, and flexibly usable subframes and slot formats. The transceiver 520 may be configured to receive data and control channels.

[0288] The node 500 may include a variety of computer-readable media. Computer-readable media may be any available media that may be accessed by the node 500 and include volatile (and / or non-volatile) media and removable (and / or non-removable) media.

[0289] The computer-readable media may include computer-storage media and communication media. Computer-storage media may include both volatile (and / or non-volatile media), and removable (and / or non-removable) media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or data.

[0290] Computer-storage media may include RAM, ROM, EPROM, EEPROM, flash memory (or other memory technology), CD-ROM, Digital Versatile Disks (DVD) (or other optical disk storage), magnetic cassettes, magnetic tape, magnetic disk storage (or other magnetic storage devices), etc. Computer-storage media may not include a propagated data signal. Communication media may typically embody computer-readable instructions (e.g., computer-readable instructions related to AI module(s) and / or the ML module(s)), data structures, program modules, or other data in a modulated data signal, such as a carrier wave, or other transport mechanisms and include any information delivery media.

[0291] The term “modulated data signal” may mean a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Communication media may include wired media, such as a wired network or direct-wired connection, and wireless media, such as acoustic, RF, infrared, and other wireless media. Combinations of any of the above listed components should also be included within the scope of computer-readable media.

[0292] The memory 534 may include computer-storage media in the form of volatile and / or non-volatile memory. The memory 534 may be removable, non-removable, or a combination thereof. Example memory may include solid-state memory, hard drives, optical-disc drives, etc. As illustrated in FIG. 5, the memory 534 may store a computer-readable and / or computer-executable instructions 532 (e.g., software codes) that are configured to, when executed, cause the processor 528 to perform various functions disclosed herein, for example, with reference to FIGS. 1 through 4. Alternatively, the instructions 532 may not be directly executable by the processor 528 but may be configured to cause the node 500 (e.g., when compiled and executed) to perform various functions disclosed herein.

[0293] The processor 528 (e.g., having processing circuitry) may include an intelligent hardware device, e.g., a Central Processing Unit (CPU), a microcontroller, an ASIC, etc. The processor 528 may include memory. The processor 528 may process the data 530 and the instructions 532 received from the memory 534, and information transmitted and received via the transceiver 520, the baseband communications module, and / or the network communications module. The processor 528 may also process information to send to the transceiver 520 for transmission via the antenna 536 to the network communications module for transmission to a CN.

[0294] One or more presentation components 538 may present data indications to a person or another device. Examples of presentation components 538 may include a display device, a speaker, a printing component, a vibrating component, etc.

[0295] In view of the present disclosure, it is obvious that various techniques may be used for implementing the disclosed concepts without departing from the scope of those concepts. Moreover, while the concepts have been disclosed with specific reference to certain implementations, a person of ordinary skill in the art may recognize that changes may be made in form and detail without departing from the scope of those concepts. As such, the disclosed implementations are to be considered in all respects as illustrative and not restrictive. It should also be understood that the present disclosure is not limited to the particular implementations disclosed and many rearrangements, modifications, and substitutions are possible without departing from the scope of the present disclosure.

Claims

1. A User Equipment (UE) for performing a random access resource management operation, the UE comprising: 　　　　at least one processor; and 　　　　at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the UE to: 　　　　　　　　receive, from a serving cell, a first configuration indicating a baseline Physical Random Access Channel (PRACH) resource; 　　　　　　　　receive, from the serving cell, a second configuration indicating at least one of a first additional PRACH resource for a contention-free random access (CFRA) procedure or a second additional PRACH resource for a contention-based random access (CBRA) procedure; and 　　　　　　　　receive, from the serving cell, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource.

2. The UE of claim 1, wherein: 　　　　the first indication is carried by a paging Downlink Control Information (DCI) with Cyclic Redundancy Check (CRC) scrambled by a Paging-Radio Network Temporary Identifier (P-RNTI) or a Medium Access Control (MAC) Control Element (CE).

3. The UE of claim 1, wherein: 　　　　the second configuration comprises a second indication for indicating whether the at least one of the first additional PRACH resource or the second additional PRACH resource is activated or deactivated by default.

4. The UE of claim 1, wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: 　　　　receive, from the serving cell, a Downlink Control Information (DCI) to initiate a Physical Downlink Control Channel (PDCCH)-order random access (RA) procedure on a target PRACH resource associated with one of the first and second additional PRACH resources; and 　　　　perform the PDCCH-order RA procedure with the serving cell on the target PRACH resource, wherein: 　　　　　　　　the PDCCH-order RA procedure is the CFRA procedure when the target PRACH resource is associated with the first additional PRACH resource, 　　　　　　　　the PDCCH-order RA procedure is the CBRA procedure when the target PRACH resource is associated with the second additional PRACH resource, 　　　　　　　　the DCI is scrambled by a Cell-Radio Network Temporary Identifier (C-RNTI) of the UE, 　　　　　　　　the second configuration comprises a Physical Cell Identifier (PCI) of the serving cell, and 　　　　　　　　the at least one of the first additional PRACH resource or the second additional PRACH resource is associated with the PCI of the serving cell.

5. The UE of claim 1, wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: 　　　　perform the CBRA procedure with the serving cell on a target PRACH resource associated with the second additional PRACH resource that is activated by the first indication, in response to determining that the CBRA procedure is triggered for a feature included in the second configuration associated with the second additional PRACH resource.

6. The UE of claim 1, wherein: 　　　　the first configuration comprises a parameter having a first value associated with the baseline PRACH resource, 　　　　the second configuration comprises the parameter having a second value associated with the first additional PRACH resource or the second additional PRACH resource, 　　　　the first value is different from the second value, and 　　　　the parameter is one of a threshold for a Downlink Reference Signal Received Power (DL-RSRP), a numerology, a periodicity, a bandwidth part (BWP), an uplink carrier, an association with Synchronization Signal Blocks (SSBs), a plurality of features, or a plurality of feature priorities corresponding to the plurality of features.

7. The UE of claim 1, wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: 　　　　store the second configuration as part of a UE inactive context upon transitioning from a Radio Resource Control (RRC) Connected state to an RRC Inactive state; and 　　　　resume the stored second configuration upon transitioning from the RRC Inactive state to the RRC Connected state.

8. A Base Station (BS) for configuring a random access resource, the BS comprising: 　　　　at least one processor; and 　　　　at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the BS to: 　　　　　　　　transmit, via a serving cell to a User Equipment (UE), a first configuration indicating a baseline Physical Random Access Channel (PRACH) resource; 　　　　　　　　transmit, via the serving cell to the UE, a second configuration indicating at least one of a first additional PRACH resource for a contention-free random access (CFRA) procedure or a second additional PRACH resource for a contention-based random access (CBRA) procedure; and 　　　　　　　　transmit, via the serving cell to the UE, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource.

9. The BS of claim 8, wherein: 　　　　the first indication is carried by a paging Downlink Control Information (DCI) with Cyclic Redundancy Check (CRC) scrambled by a Paging-Radio Network Temporary Identifier (P-RNTI) or a Medium Access Control (MAC) Control Element (CE).

10. The BS of claim 8, wherein: 　　　　the second configuration comprises a second indication for indicating whether the at least one of the first additional PRACH resource or the second additional PRACH resource is activated or deactivated by default.

11. The BS of claim 8, wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the BS to: 　　　　transmit, to the UE, a Downlink Control Information (DCI) to initiate a Physical Downlink Control Channel (PDCCH)-order random access (RA) procedure on a target PRACH resource associated with one of the first and second additional PRACH resources, wherein: 　　　　　　　　the UE performs the PDCCH-order RA procedure with the serving cell on the target PRACH resource, 　　　　　　　　the PDCCH-order RA procedure is the CFRA procedure when the target PRACH resource is associated with the first additional PRACH resource, 　　　　　　　　the PDCCH-order RA procedure is the CBRA procedure when the target PRACH resource is associated with the second additional PRACH resource, 　　　　　　　　the DCI is scrambled by a Cell-Radio Network Temporary Identifier (C-RNTI) of the UE, 　　　　　　　　the second configuration comprises a Physical Cell Identifier (PCI) of the serving cell, and 　　　　　　　　the at least one of the first additional PRACH resource or the second additional PRACH resource is associated with the PCI of the serving cell.

12. The BS of claim 8, wherein: 　　　　the UE performs the CBRA procedure with the serving cell on a target PRACH resource associated with the second additional PRACH resource that is activated by the first indication, in response to determining that the CBRA procedure is triggered for a feature included in the second configuration associated with the second additional PRACH resource.

13. The BS of claim 8, wherein: 　　　　the first configuration comprises a parameter having a first value associated with the baseline PRACH resource, 　　　　the second configuration comprises the parameter having a second value associated with the first additional PRACH resource or the second additional PRACH resource, 　　　　the first value is different from the second value, and 　　　　the parameter is one of a threshold for a Downlink Reference Signal Received Power (DL-RSRP), a numerology, a periodicity, a bandwidth part (BWP), an uplink carrier, an association with Synchronization Signal Blocks (SSBs), a plurality of features, or a plurality of feature priorities corresponding to the plurality of features.

14. The BS of claim 8, wherein: 　　　　the UE stores the second configuration as part of a UE inactive context upon transitioning from a Radio Resource Control (RRC) Connected state to an RRC Inactive state, and 　　　　the UE resumes the stored second configuration upon transitioning from the RRC Inactive state to the RRC Connected state.

15. A method performed by a User Equipment (UE) for performing a random access resource management operation, the method comprising: 　　　　receiving, from a serving cell, a first configuration indicating a baseline Physical Random Access Channel (PRACH) resource; 　　　　receiving, from the serving cell, a second configuration indicating at least one of a first additional PRACH resource for a contention-free random access (CFRA) procedure or a second additional PRACH resource for a contention-based random access (CBRA) procedure; and 　　　　receiving, from the serving cell, a first indication that activates or deactivates at least one of the first additional PRACH resource or the second additional PRACH resource.

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