Cross-carrier random access channel transmission trigger

Abstract

Certain aspects of the present disclosure provide a method of wireless communication by a user equipment (UE), the method generally including receiving signaling to configure a set of candidate cells for the UE, a downlink control information (DCI) indicating one candidate cell of the group of candidate cells as a target cell for transmitting a physical random access channel (PRACH) is received from a serving cell, and the PRACH is transmitted in the target cell.

Description

Background Art Technical Field

[0001] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for cross-carrier random access channel triggering.

[0002] Related technologies

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts or other similar types of services. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available wireless communication system resources with those users.

[0004] Although wireless communication systems have made tremendous technical progress over the years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers. Therefore, there is a continuous desire to improve the technical performance of wireless communication systems, including, for example: improving the speed and data carrying capacity of communications, improving the efficiency of using shared communication media, reducing the power used by transmitters and receivers when performing communications, improving the reliability of wireless communications, avoiding redundant transmission and / or reception and related processing, improving the coverage area of ​​wireless communications, increasing the number and types of devices that can access wireless communication systems, increasing the ability of different types of devices to communicate with each other, increasing the number and types of wireless communication media available for use, etc. Therefore, there is a need to further improve wireless communication systems to overcome the above-mentioned technical challenges and other challenges. Summary of the invention

[0005] One aspect provides a method for wireless communication by a user equipment (UE). The method includes receiving signaling for configuring a group of candidate cells for the UE; receiving downlink control information (DCI) from a serving cell indicating a candidate cell in the group of candidate cells as a target cell for sending a physical random access channel (PRACH); and sending the PRACH in the target cell.

[0006] Another aspect provides a method for wireless communication by a network entity. The method includes sending signaling to configure a group of candidate cells for a UE; and sending a DCI indicating a candidate cell in the group of candidate cells as a target cell for the UE to send a PRACH.

[0007] Other aspects provide: an apparatus operable to, configured to, or otherwise adapted to perform any one or more of the foregoing methods and / or those described elsewhere herein; a non-transitory computer-readable medium comprising instructions that, when executed by a processor of the apparatus, cause the apparatus to perform the foregoing methods and those described elsewhere herein; a computer program product embodied on a computer-readable storage medium, the computer program product comprising code for performing the foregoing methods and those described elsewhere herein; and / or an apparatus comprising components for performing the foregoing methods and those described elsewhere herein. By way of example, an apparatus may include a processing system, a device having a processing system, or a processing system cooperating through one or more networks.

[0008] For purposes of illustration, the following description and drawings set forth certain features. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings depict certain features of the aspects described herein and should not be considered to limit the scope of the disclosure.

[0010] Figure 1 An example wireless communication network is depicted.

[0011] Figure 2 An example disaggregated base station architecture is depicted.

[0012] Figure 3 Aspects of an example base station and example user equipment are depicted.

[0013] Figure 4A , Figure 4B , Figure 4C and Figure 4D Various example aspects of data structures for a wireless communication network are described.

[0014] Figure 5 A scenario with a pre-configured set of candidate primary cells (PCells) is depicted.

[0015] Figure 6 Another selection scenario with a pre-configured candidate PCell group is depicted.

[0016] Figure 7 A scenario with a pre-configured candidate cell group (CG) group is depicted.

[0017] Figure 8 Depicted is a call flow diagram of an example cross-carrier physical random access channel (PRACH) triggering in accordance with aspects of the present disclosure.

[0018] Fig. 9

[0013] An example of cross-carrier PRACH triggering through DCI is depicted in accordance with aspects of the present disclosure.

[0019] Fig.10 A method for wireless communication is described.

[0020] Fig.11 A method for wireless communication is described.

[0021] Fig.12 Aspects of an example communications device are depicted.

[0022] Fig.13 Aspects of an example communications device are depicted. DETAILED DESCRIPTION

[0023] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for cross-carrier PRACH triggering via DCI.

[0024] In the random access channel (RACH) procedure, the user equipment (UE) transmits a first message called a physical RACH (PRACH) preamble to a network entity (e.g., a base station) to synchronize the cell. Currently, the PRACH trigger from the network entity can only be based on higher layer signaling (which may have a large latency) or the physical downlink control channel (PDCCH) which does not support cross-carrier triggering.

[0025] In some cases, the primary cell (Pcell) may be changed to a new candidate Pcell, but the UE may not receive data or control information in the candidate Pcell. In such cases, a timing adjustment to the new candidate cell may be required before the Pcell is changed. Although PRACH transmissions are typically used to determine such timing adjustments, cross-carrier PRACH triggering that would allow timing adjustments in candidate Pcells is typically not supported.

[0026] However, aspects of the present disclosure provide techniques for triggering PRACH transmission in candidate cells for uplink (UL) timing via downlink control information (DCI) from a serving cell. For example, a UE may be configured with a set of candidate cells and then receive a DCI from a serving cell indicating one of the candidate cells as a target cell for transmitting PRACH. The techniques disclosed herein can significantly reduce the latency associated with PRACH triggering while enabling cross-carrier PRACH triggering in layer 1 (L1) and layer 2 (L2) based mobility.

[0027] Introduction to wireless communication networks

[0028] The techniques and methods described herein can be used in various wireless communication networks. Although various aspects may be described herein using terms commonly associated with 3G, 4G and / or 5G wireless technologies, various aspects of the present disclosure may also be applicable to other communication systems and standards not explicitly mentioned herein.

[0029] Figure 1 An example of a wireless communication network 100 is depicted in which various aspects described herein may be implemented.

[0030] In general, the wireless communication network 100 includes various network entities (alternatively, network elements or network nodes). A network entity is typically a communication device and / or a communication function performed by a communication device (e.g., user equipment (UE), base station (BS), component of a BS, server, etc.). For example, various functions of a network and various devices associated with and interacting with the network may be considered network entities. In addition, the wireless communication network 100 includes ground aspects, such as ground-based network entities (e.g., BS 102), and non-ground aspects, such as satellites 140 and aircraft 145, which may include airborne network entities (e.g., one or more BSs) capable of communicating with other network elements (e.g., ground BSs) and user equipment.

[0031] In the depicted example, the wireless communication network 100 includes a BS 102, a UE 104, and one or more core networks (such as an evolved packet core (EPC) 160 and a 5G core (5GC) network 190) that interoperate to provide communication services over various communication links (including wired and wireless links).

[0032] Figure 1 Various example UEs 104 are depicted, which may more generally include: a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player, a camera, a game console, a tablet computer, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, an Internet of Things (IoT) device, an Always-On (AON) device, an edge processing device, or other similar devices. UE 104 may also be more generally referred to as a mobile device, a wireless device, a wireless communication device, a station, a mobile station, a subscriber station, a mobile subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a remote device, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, and others.

[0033] BS 102 wirelessly communicates with (e.g., transmits signals to or receives signals from) UE 104 via communication link 120. Communication link 120 between BS 102 and UE 104 may include uplink (UL) (also referred to as a reverse link) transmissions from UE 104 to BS 102 and / or downlink (DL) (also referred to as a forward link) transmissions from BS 102 to UE 104. In various aspects, communication link 120 may employ multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity.

[0034] BS 102 may generally include: NodeB, enhanced NodeB (eNB), next generation enhanced NodeB (ng-eNB), next generation NodeB (gNB or gNodeB), access point, base transceiver, radio base station, radio transceiver, transceiver function, transmission and reception point, and / or other. Each of BS 102 may provide communication coverage for a corresponding geographic coverage area 110, which may sometimes be referred to as a cell, and may overlap in some cases (e.g., a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of a macro cell). For example, a BS may provide communication coverage for a macro cell (covering a relatively large geographic area), a pico cell (covering a relatively small geographic area, such as a stadium), a femto cell (relatively small geographic area (e.g., a home)), and / or other types of cells.

[0035] Although BS102 is depicted as a single communication device in various aspects, BS102 can be implemented in various configurations. For example, one or more components of the base station may be decomposed, including a central unit (CU), one or more distributed units (DU), one or more radio units (RU), a near real-time (near RT) RAN intelligent controller (RIC), or a non-real-time (non-RT) RIC, to name a few examples. In another example, various aspects of the base station may be virtualized. More generally, a base station (e.g., BS102) may include components located at a single physical location or components located at various physical locations. In an example in which the base station includes components located at various physical locations, the various components may each perform a function so that the various components together implement functions similar to those of a base station located at a single physical location. In some aspects, a base station including components located at various physical locations may be referred to as a decomposed radio access network architecture (such as an open RAN (O-RAN) or virtualized RAN (VRAN) architecture). Figure 2 An example decomposed base station architecture is depicted and described.

[0036] Different BSs 102 within the wireless communication network 100 may also be configured to support different radio access technologies (such as 3G, 4G, and / or 5G). For example, a BS 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). A BS 102 configured for 5G (e.g., 5G NR or Next Generation RAN (NG-RAN)) may interface with the 5GC 190 via a second backhaul link 184. The BSs 102 may communicate with each other directly or indirectly (e.g., via the EPC 160 or the 5GC 190) over a third backhaul link 134 (e.g., an X2 interface), which may be wired or wireless.

[0037] The wireless communication network 100 may subdivide the electromagnetic spectrum into various categories, frequency bands, channels, or other characteristics. In some aspects, the subdivision is provided based on wavelength and frequency, where frequency may also be referred to as a carrier, subcarrier, channel, tone, or subband. For example, 3GPP currently defines frequency range 1 (FR1) as including 410 MHz–7125 MHz, which is often (interchangeably) referred to as “below 6 GHz”. Similarly, 3GPP currently defines frequency range 2 (FR2) as including 24,250 MHz-52,600 MHz, which is sometimes (interchangeably) referred to as “millimeter wave” (“mmW” or “mmWave”). A base station (e.g., a mmWave base station such as BS180) configured to communicate using mmWave / near mmWave radio bands may utilize beamforming (e.g., 182) with a UE (e.g., 104) to improve path loss and range.

[0038] The communication link 120 between the BS 102 and, for example, the UE 104 may be through one or more carriers, which may have different bandwidths (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, and / or other MHz) and may be aggregated in various aspects. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​compared to UL).

[0039] Communications using higher frequency bands may have higher path loss and shorter range than communications at lower frequencies. Figure 1180) may utilize beamforming 182 with UE 104 to improve path loss and range. For example, BS 180 and UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays, to facilitate beamforming. In some cases, BS 180 may send beamformed signals to UE 104 in one or more transmit directions 182'. UE 104 may receive beamformed signals from BS 180 in one or more receive directions 182". UE 104 may also send beamformed signals to BS 180 in one or more transmit directions 182". BS 180 may also receive beamformed signals from UE 104 in one or more receive directions 182'. BS 180 and UE 104 may then perform beam training to determine the best receive direction and transmit direction for each of BS 180 and UE 104. It is noteworthy that the transmit direction and receive direction of BS 180 may be the same or may not be the same. Similarly, the transmit direction and receive direction of UE 104 may or may not be the same.

[0040] Wireless communication network 100 also includes Wi-Fi AP 150 that communicates with Wi-Fi stations (STAs) 152 via communication links 154 in, for example, the 2.4 GHz and / or 5 GHz unlicensed spectrum.

[0041] Certain UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), and / or a physical sidelink feedback channel (PSFCH).

[0042] The EPC 160 may include various functional components, including: a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and / or a packet data network (PDN) gateway 172, such as in the depicted example. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management.

[0043] Generally speaking, user Internet Protocol (IP) packets are delivered through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation and other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176, which may include, for example, the Internet, an Intranet, an IP Multimedia Subsystem (IMS), a Packet Switched (PS) streaming media service, and / or other IP services.

[0044] The BM-SC 170 may provide functionality for MBMS user service configuration and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS delivery, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and / or may be used to schedule MBMS delivery. The MBMS Gateway 168 may be used to distribute MBMS services to BSs 102 belonging to a multicast broadcast single frequency network (MBSFN) area broadcasting a specific service, and / or may be responsible for session management (start / stop) and for collecting eMBMS related charging information.

[0045] 5GC 190 may include various functional components, including: access and mobility management function (AMF) 192, other AMFs 193, session management function (SMF) 194, and user plane function (UPF) 195. AMF 192 may communicate with unified data management (UDM) 196.

[0046] AMF 192 is a control node that handles signaling between UE 104 and 5GC 190. AMF 192 provides, for example, Quality of Service (QoS) flow and session management.

[0047] Internet Protocol (IP) packets are delivered through UPF 195, which is connected to IP Services 197 and provides IP address allocation for UEs and other functions for 5GC 190. IP Services 197 may include, for example, the Internet, Intranet, IMS, PS streaming services, and / or other IP services.

[0048] In various aspects, a network entity or network node may be implemented as a converged base station, a decomposed base station, a component of a base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, to name a few examples.

[0049] Figure 2An example disaggregated base station 200 architecture is depicted. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that may communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 225 via an E2 link, or a non-real-time (non-RT) RIC 215 associated with a service management and orchestration (SMO) framework 205, or both. The CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DU 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RU 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served simultaneously by multiple RUs 240.

[0050] Each of the units (e.g., CU 210, DU 230, RU 240, and near-RT RIC 225, non-RT RIC 215, and SMO framework 205) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interface of the unit may be configured to communicate with one or more of the other units via a transmission medium. For example, the units may include a wired interface configured to receive or send signals to one or more of the other units via a wired transmission medium. Additionally or alternatively, the unit may include a wireless interface that may include a receiver, transmitter, or transceiver (such as a radio frequency (RF) transceiver) configured to receive signals on a wireless transmission medium or send signals to one or more of the other units, or both.

[0051] In some aspects, CU 210 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function can be implemented using an interface that is configured to communicate signals with other control functions hosted by CU 210. CU210 may be configured to handle user plane functionality (e.g., central unit-user plane (CU-UP)), control plane functionality (e.g., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 210 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 210 may be implemented to communicate with DU 230 for network control and signaling.

[0052] DU 230 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 240. In some aspects, DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) at least in part according to a functional split such as those defined by the 3rd Generation Partnership Project (3GPP). In some aspects, DU 230 may further host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 230 or with control functions hosted by CU 210.

[0053] The lower layer functions may be implemented by one or more RUs 240. In some deployments, a RU 240 controlled by a DU 230 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing Fast Fourier Transform (FFT), Inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on a functional split such as a lower layer functional split. In such an architecture, the RU 240 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU 240 may be controlled by the corresponding DU 230. In some scenarios, this configuration may enable the implementation of the DU 230 and the CU 210 in a cloud-based RAN architecture (such as a vRAN architecture).

[0054] The SMO framework 205 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 210, DU 230, RU 240, and near-RT RIC 225. In some specific implementations, the SMO framework 205 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 211) via the O1 interface. Additionally, in some specific implementations, the SMO framework 205 may communicate directly with one or more RUs 240 via the O1 interface. The SMO framework 205 may also include a non-RT RIC 215 configured to support the functionality of the SMO framework 205 .

[0055] The non-RT RIC 215 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 225. The non-RT RIC 215 may be coupled to or in communication with the near-RT RIC 225 (such as via an A1 interface). The near-RT RIC 225 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 210, one or more DUs 230, or both, and the O-eNB with the near-RT RIC 225.

[0056] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 225, the non-RT RIC 215 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 225 and may be received from a non-network data source or from a network function at the SMO framework 205 or the non-RT RIC 215. In some examples, the non-RT RIC 215 or the near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 215 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 205 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0057] Figure 3 Aspects of an example BS 102 and UE 104 are depicted.

[0058] In general, BS 102 includes various processors (e.g., 320, 330, 338, and 340), antennas 334a-334t (collectively 334), transceivers 332a-332t (collectively 332) including modulators and demodulators, and other aspects that enable wireless transmission of data (e.g., data source 312) and wireless reception of data (e.g., data sink 339). For example, BS 102 can transmit and receive data between BS 102 and UE 104. BS 102 includes a controller / processor 340 that can be configured to implement various functions described herein related to wireless communication.

[0059] In general, the UE 104 includes various processors (e.g., 358, 364, 366, and 380), antennas 352a-352r (collectively 352), transceivers 354a-354r (collectively 354) including modulators and demodulators, and other aspects that enable wireless transmission of data (e.g., retrieved from a data source 362) and wireless reception of data (e.g., provided to a data sink 360). The UE 104 includes a controller / processor 380 that can be configured to implement various functions described herein related to wireless communications.

[0060] Regarding example downlink transmissions, BS 102 includes a transmit processor 320 that can receive data from a data source 312 and control information from a controller / processor 340. The control information can be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical HARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), and / or others. In some examples, the data can be for a physical downlink shared channel (PDSCH).

[0061] The transmit processor 320 may process (e.g., encode and symbol map) data and control information to obtain data symbols and control symbols, respectively. The transmit processor 320 may also generate reference symbols (such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH demodulation reference signal (DMRS), and a channel state information reference signal (CSI-RS)).

[0062] The transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., pre-coding) on ​​data symbols, control symbols, and / or reference symbols, where applicable, and may provide an output symbol stream to a modulator (MOD) in a transceiver 332a-332t. Each modulator in the transceiver 332a-332t may process a corresponding output symbol stream to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from the modulators in the transceivers 332a-332t may be transmitted via antennas 334a-334t, respectively.

[0063] To receive downlink transmissions, UE 104 includes antennas 352a-352r that can receive downlink signals from BS 102 and can provide received signals to demodulators (DEMODs) in transceivers 354a-354r, respectively. Each demodulator in transceivers 354a-354r can condition (e.g., filter, amplify, downconvert, and digitize) a corresponding received signal to obtain input samples. Each demodulator can further process the input samples to obtain received symbols.

[0064] A MIMO detector 356 may obtain received symbols from all demodulators in transceivers 354a-354r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 104 to a data sink 360, and provide decoded control information to a controller / processor 380.

[0065] With respect to example uplink transmissions, the UE 104 also includes a transmit processor 364 that may receive and process data from a data source 362 (e.g., for a PUSCH) and control information from a controller / processor 380 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 364 may also generate reference symbols for reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 364 may be pre-decoded by a TX MIMO processor 366, if applicable, further processed by a modulator in the transceivers 354a-354r (e.g., for SC-FDM), and transmitted to the BS 102.

[0066] At BS 102, uplink signals from UE 104 may be received by antennas 334 a-334 t, processed by demodulators in transceivers 332 a-332 t, detected by MIMO detector 336 if applicable, and further processed by receive processor 338 to obtain decoded data and control information transmitted by UE 104. Receive processor 338 may provide decoded data to data sink 339 and decoded control information to controller / processor 340.

[0067] Memories 342 and 382 may store data and program codes for BS 102 and UE 104, respectively.

[0068] Scheduler 344 may schedule UEs for data transmission on the downlink and / or uplink.

[0069] In various aspects, the BS 102 may be described as sending and receiving various types of data associated with the methods described herein. In these contexts, "sending" may refer to various mechanisms for outputting data, such as outputting data from a data source 312, a scheduler 344, a memory 342, a transmit processor 320, a controller / processor 340, a TX MIMO processor 330, a transceiver 332a-332t, an antenna 334a-334t, and / or other aspects described herein. Similarly, "receiving" may refer to various mechanisms for obtaining data, such as obtaining data from an antenna 334a-334t, a transceiver 332a-332t, a RX MIMO detector 336, a controller / processor 340, a receive processor 338, a scheduler 344, a memory 342, and / or other aspects described herein.

[0070] In various aspects, the UE 104 may also be described as sending and receiving various types of data associated with the methods described herein. In these contexts, "sending" may refer to various mechanisms for outputting data, such as outputting data from a data source 362, a memory 382, ​​a transmit processor 364, a controller / processor 380, a TX MIMO processor 366, a transceiver 354a-354t, an antenna 352a-352t, and / or other aspects described herein. Similarly, "receiving" may refer to various mechanisms for obtaining data, such as obtaining data from an antenna 352a-352t, a transceiver 354a-354t, a RX MIMO detector 356, a controller / processor 380, a receive processor 358, a memory 382, ​​and / or other aspects described herein.

[0071] In some aspects, the processor may be configured to perform various operations (such as those associated with the methods described herein) and send (output) data to or receive (obtain) data from another interface configured to send or receive data, respectively.

[0072] Figure 4A , Figure 4B , Figure 4C and Figure 4D Describes a method for use in a wireless communication network such as Figure 1 Various aspects of the data structure of the wireless communication network 100).

[0073] Specifically, Figure 4A is a diagram 400 illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure, Figure 4B is a diagram 430 illustrating an example of a DL channel within a 5G subframe, Figure 4C is a diagram 450 illustrating an example of a second subframe within a 5G frame structure, and Figure 4D FIG480 is a diagram illustrating an example of UL channels within a 5G subframe.

[0074] Wireless communication systems may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on both the uplink and downlink. Such systems may also support half-duplex operation using time division duplex (TDD). OFDM and single carrier frequency division multiplexing (SC-FDM) can be used to maximize the system bandwidth (e.g., Figure 4B and Figure 4D The modulation symbols may be transmitted in the frequency domain using OFDM and / or in the time domain using SC-FDM.

[0075] The wireless communication frame structure may be frequency division duplex (FDD), where for a particular set of subcarriers, subframes within the set of subcarriers are dedicated to either DL or UL. The wireless communication frame structure may also be time division duplex (TDD), where for a particular set of subcarriers, subframes within the set of subcarriers are dedicated to both DL and UL.

[0076] exist Figure 4A and Figure 4C In the wireless communication frame structure, TDD is used, where D is DL, U is UL, and X is used flexibly between DL / UL. The UE can be configured with a time slot format (dynamically configured by DL control information (DCI) or semi-statically / statically configured by radio resource control (RRC) signaling) through the received time slot format indicator (SFI). In the depicted example, the 10ms frame is divided into 10 equally sized 1ms subframes. Each subframe may include one or more time slots. In some examples, each time slot may include 7 or 14 symbols, depending on the time slot format. The subframe may also include a micro-time slot, which generally has fewer symbols than the entire time slot. Other wireless communication technologies may have different frame structures and / or different channels.

[0077] In certain aspects, the number of slots within a subframe is based on the slot configuration and parameter set. For example, for slot configuration 0, different parameter sets (μ) 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots per subframe, respectively. For slot configuration 1, different parameter sets 0 to 2 allow for 2, 4, and 8 slots per subframe, respectively. Thus, for slot configuration 0 and parameter set μ, there are 14 symbols / slot and 2μ slots / subframe. The subcarrier spacing and symbol length / duration are a function of the parameter set. The subcarrier spacing may be equal to 2 μ × 15kHz, where μ is parameter set 0 to 5. Thus, parameter set μ=0 has a subcarrier spacing of 15kHz, and parameter set μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figure 4A , Figure 4B , Figure 4C and Figure 4D An example is provided for slot configuration 0 with 14 symbols per slot and parameter set μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

[0078] like Figure 4A , Figure 4B , Figure 4C and Figure 4DAs depicted in , a resource grid can be used to represent a frame structure. Each time slot includes a resource block (RB) (also called a physical RB (PRB)) extending, for example, 12 consecutive subcarriers. The resource grid is divided into a plurality of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0079] like Figure 4A As illustrated, some REs carry Figure 1 and Figure 3 The RS may include a demodulation RS (DMRS) and / or a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and / or a phase tracking RS (PT-RS).

[0080] Figure 4B Examples of various DL channels within a subframe of a frame are illustrated.The Physical Downlink Control Channel (PDCCH) carries DCI within one or more Control Channel Elements (CCEs), each CCE comprising, for example, nine RE Groups (REGs), each REG comprising, for example, four consecutive REs in an OFDM symbol.

[0081] The primary synchronization signal (PSS) may be in symbol 2 of a particular subframe of a frame. The PSS is transmitted by a UE (e.g., Figure 1 and Figure 3 104) is used to determine subframe / symbol timing and physical layer identification.

[0082] A Secondary Synchronization Signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing.

[0083] Based on the physical layer identifier and the physical layer cell identifier group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DMRS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the system frame number (SFN) and the number of RBs in the system bandwidth. The physical downlink shared channel (PDSCH) carries user data, broadcast system information (such as system information blocks (SIBs)) that is not sent via the PBCH, and / or paging messages.

[0084] As in Figure 4CAs illustrated in , some REs carry DMRS for channel estimation at the base station (indicated as R for a specific configuration, but other DMRS configurations are possible). The UE may send DMRS for PUCCH and DMRS for PUSCH. The PUSCH DMRS may be sent, for example, in the first one or two symbols of the PUSCH. The PUCCH DMRS may be sent in different configurations depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used. UE 104 may send a sounding reference signal (SRS). The SRS may be sent, for example, in the last symbol of a subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the teeth of the comb. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

[0085] Figure 4D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at a position as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0086] Overview of CA Cell Group

[0087] In carrier aggregation (CA), cells may be divided into groups referred to as primary cell groups (MCGs) and secondary cell groups (SCGs). A UE supporting dual connectivity (DC) may establish connections with cells in both MCGs and SCGs. The MCG may be a group including cells in which the UE first initiates a random access channel (RACH) procedure.

[0088] There may be many different types of cells under MCG. A cell used for initial access is called a primary cell (PCell). CA is used to effectively combine the PCell in MCG and the secondary cell (SCell) in MCG. There is also a primary cell called PSCell in SCG, for which initial access is initiated under SCG. CA can also be used to effectively combine the PSCell and SCell under SCG. Because most signaling messages are transmitted only on PCell and PSCell, the protocol also defines the concept of a special cell (sPCell), which refers to PCell and PSCell.

[0089] Overview of Mobility Based on Dynamic Signaling

[0090] Dynamic mobility signaling (eg, L1 and / or L2 centric mobility) can facilitate intra-cell and inter-cell mobility and reduce latency. The general concept of L1 / L2 based mobility signaling can be described as follows.

[0091] The network may configure (e.g., via RRC signaling) a set of cells for L1 / L2 mobility (referred to herein as an L1 / L2 mobility configured cell group). At any given time, the network may also configure (via L1 / L2 signaling) an L1 / L2 mobility activated cell group, which refers to a group of cells in the configured group that are activated and can be easily used for data and control transmission. The network may also configure (signal) an L1 / L2 mobility deactivated cell group, which refers to a group of cells in the configured group that are deactivated and can be easily activated by L1 / L2 signaling.

[0092] L1 / L2 signaling can be used for mobility management of the activation group. For example, L1 / L2 signaling can be used to activate / deactivate cells in the group, select beams within the activated cells, and update / switch PCells. This dynamic signaling can help provide seamless mobility within the activated cells in the group. In other words, as the UE moves, cells from the group are deactivated and activated by L1 / L2 signaling. The cells to be activated and deactivated can be based on various factors, such as signal quality (measurements) and load.

[0093] In some cases, all cells in an L1 / L2 mobility configuration cell group may belong to the same DU. This may be similar to carrier aggregation (CA), but the cells may be on the same carrier frequency. The size of the cell group configured for L1 / L2 mobility signaling may vary. In general, the cell group size may be chosen to be large enough to cover a meaningful mobility area.

[0094] In some cases, the UE may be provided with a subgroup of deactivated cells as a candidate cell group from which the UE may autonomously select cells to add to the activated cell group. The decision whether to add a cell from the candidate cell group to the activated cell group may be based on various factors, such as measured channel quality and load information. In some cases, the UE's ability to autonomously select cells to add to the activated cell group may be similar to the UE decision when configured for conditional handover (CHO) to quickly and efficiently add prepared cells.

[0095] For primary cell (PCell) management, L1 / L2 signaling can be used to set (select) the PCell from pre-configured options within the activated cell group. In some cases, when the new PCell is not from the activated cell group for L1 / L2 mobility, L3 mobility can be used for PCell change (L3 handover). In such cases, RRC signaling can update the set of cells for L1 / L2 mobility at L3 handover.

[0096] In some cases, physical layer (layer 1 or L1) measurements may be enhanced for L1 / L2 mobility, where the serving cell may be changed via L1 / L2 signaling based on the L1 measurements, and both synchronous and asynchronous source and target cells may be considered.

[0097] Various mechanisms and procedures for inter-cell mobility based on L1 / L2 may be specified to reduce mobility latency. These may include configuration and maintenance for multiple candidate cells to allow rapid application of configurations for candidate cells. For potential application scenarios based on L1 / L2 signaling, dynamic switching mechanisms between candidate serving cells (including SpCells and SCells) may be supported.

[0098] L1 enhancements for inter-cell beam management may include L1 measurements and reporting as well as beam indication. Timing advance (TA) management and CU-DU interface signaling may also be provided to support L1 / L2 mobility.

[0099] The L1 / L2 based inter-cell mobility procedure is applicable to a variety of scenarios. These scenarios may include standalone, CA and new radio dual connectivity (NR-DC) cases with serving cell change within a cell group (CG), intra-distributed unit (DU) cases and inter-DU cases within a central unit (CU), intra-frequency and inter-frequency scenarios, both FR1 and FR2 scenarios, and scenarios where the source cell and the target cell may be synchronized or unsynchronized.

[0100] Aspects related to cross-carrier PRACH triggering via DCI

[0101] As mentioned above, PRACH triggering from a network entity is usually based on higher layer signaling which suffers from large delays, or via PDCCH which does not support cross-carrier triggering.

[0102] However, aspects of the present disclosure provide techniques for triggering PRACH transmission in a candidate cell for uplink (UL) timing via downlink control information (DCI) from a serving cell. This may be beneficial in situations where a primary cell (Pcell) may be changed to a new candidate Pcell but the UE may not receive data or control information in the candidate Pcell. Aspects of the present disclosure may help facilitate timing adjustments to new candidate cells before a Pcell change.

[0103] The techniques presented in this article can help facilitate timing adjustments for a variety of different cell selection scenarios. For example, these techniques can be used to Figure 5 The separate cell selection scenario (referred to as Class 1) illustrated in FIG, where PCell change and SCell change use separate signaling in the case of CA. In some cases, beam indication may be based on PCell selection. SCell selection may be based on conventional (legacy) signaling or new L1 / L2 signaling.

[0104] Figure 5 The example in assumes that a single PCell without CA / DC is selected from the pre-configured set of candidate PCells (when the UE moves from the old PCell to the new PCell). The techniques presented in this article can also be used for Figure 6 In the scenario shown in , where the PCell change occurs via a Pcell to SCell switch in a pre-configured candidate PCell set.

[0105] The techniques presented in this article can also be used Figure 7 In the scenario shown in , selection based on cell group (CG) (called type 2) is used. In this case, in case of CA, SpCell and SCell can be switched together. CG switch signaling can be based on Figure 5 and Figure 6 An extension of the signaling for the Type 1 scenario shown in .

[0106] As mentioned above, there is usually no mechanism for triggering PRACH on another cell. This is because the cell ID indicated in the triggering downlink control information (DCI) that is usually used to trigger PRACH does not exist. Therefore, Figures 5 to 7 There is a problem with the timing adjustment of the cell selection scenario shown in .

[0107] For reference Figure 8 The techniques presented herein for triggering cross-CC PRACH transmissions may be understood with reference to call flow diagram 800 .

[0108] As illustrated, the UE may be configured with a set of candidate cells by the current serving cell. The current serving cell may trigger the UE to send PRACH on the target cell. For example, the current serving cell may trigger PRACH transmission by transmitting a DCI indicating one of the candidate cells as the target cell for sending PRACH. In response, the UE may send PRACH to the target cell.

[0109] Fig. 9An example timeline of cross-CC PRACH transmission triggered via DCI is illustrated. As illustrated, the PCell commands a PRACH transmission in a candidate cell via DCI. In response, the UE sends a PRACH transmission to the candidate cell. The network may then determine a timing adjustment (TA) value and provide the value to the UE via a TA command (TAC). The UE may then apply the TA value when communicating in the candidate cell.

[0110] In this way, when the UE is configured with a set of candidate cells for Pcell change purposes via L1 and L2 based mobility, the UE can be triggered via the PDCCH in the serving cell to send PRACH in one of the candidate cells. In some cases, the ID of the target candidate Pcell can be included in the DCI used to trigger the PRACH from the serving cell (e.g., using format 1_0).

[0111] In other cases, a different DCI format (e.g., DCI format 1_1) may be configured with a carrier indicator field (CIF) to trigger the PRACH from the serving cell. In such cases, the candidate Pcell may be associated with one CIF value in DCI format 1_1.

[0112] In some cases, if the cyclic redundancy check (CRC) of the DCI format 1_1 with the CIF field is scrambled by the cell radio network temporary identifier (C-RNTI) and the bits of the frequency domain resource allocation (FDRA) field are all set to 1, this can be an indication that the DCI format 1_1 is used for a random access procedure initiated by a PDCCH order. For example, this method can be applied when the UE does not receive PDCCH and physical downlink shared channel (PDSCH) transmissions in the candidate Pcell.

[0113] The target Pcell for PRACH transmission may be associated with the CIF value indicated in the CIF field. For example, the candidate Pcell index may have X bits depending on the size of the candidate Pcell group. For example, if there are two candidate Pcells in the group, the value of X may be 1.

[0114] In some cases, if the CRC of DCI format 1_1 with a CIF field is scrambled by the C-RNTI and the FDRA fields are all set to 1, DCI format 1_1 can be used for a random access procedure initiated by a PDCCH command, where the target Pcell for the random access transmission can be associated with the CIF value indicated in the CIF field.

[0115] Example Operation of User Equipment

[0116] Fig.10It is shown that a UE (such as Figure 1 and Figure 3 An example of a method 1000 for performing wireless communications with a UE 104).

[0117] Method 1000 begins at step 1005, namely receiving a signaling to configure a set of candidate cells for the UE. In some cases, the operation of this step refers to the following steps: Fig.12 The circuit for receiving and / or the code for receiving may be executed by the circuit and / or the code.

[0118] Then, the method 1000 proceeds to step 1010, that is, receiving a DCI indicating one of the candidate cells as a target cell for transmitting the PRACH from the serving cell. In some cases, the operation of this step refers to the following steps. Fig.12 The circuit for receiving and / or the code for receiving may be executed by the circuit and / or the code.

[0119] Then, the method 1000 proceeds to step 1015, that is, sending the PRACH in the target cell. In some cases, the operation of this step refers to the operation of Fig.12 The circuit for sending and / or the code for sending may be executed by the circuit and / or the code.

[0120] In some aspects, the set of candidate cells supports mobility signaling via the PHY layer or MAC layer signaling.

[0121] In some aspects, the method 1000 further includes receiving a TA command from the serving cell to apply in the target cell. In some cases, the operation of this step refers to the following Fig.12 The circuit for receiving and / or the code for receiving may be executed by the circuit and / or the code.

[0122] In some aspects, the DCI indicates the target cell by including the ID of the candidate cell.

[0123] In some aspects, the ID is included in the Candidate Pcell Index field of the DCI.

[0124] In some aspects, the DCI indicates the target cell via the CIF.

[0125] In some aspects, the value of the CIF is associated with the target cell.

[0126] In some aspects, a DCI indicates that a value of the CIF is associated with a target cell if the following conditions exist: the CRC of the DCI is scrambled with a certain RNTI; and bits of the FDRA field of the DCI are set to certain values.

[0127] In one aspect, method 1000 or any aspect related thereto may be performed by an apparatus such as Fig.12 The method 1000 is performed by a communication device 1200 that includes various components operable, configured or adapted to perform the method 1000. The communication device 1200 is described in more detail below.

[0128] Please note that Fig.10 This is merely one example of a method, and other methods including fewer, additional, or alternative steps are also possible consistent with the present disclosure.

[0129] Example Operations of Network Entities

[0130] Fig.11 shows the network entities such as Figure 1 and Figure 3 BS102 or such Figure 2 An example of a method 1100 for performing wireless communications using a decomposed base station) as discussed above.

[0131] Method 1100 begins at step 1105, i.e., sending a signaling to configure a set of candidate cells for the UE. In some cases, the operation of this step refers to the following steps: Fig.13 The circuit for sending and / or the code for sending may be executed by the circuit and / or the code.

[0132] Then, the method 1100 proceeds to step 1110, that is, sending a DCI indicating one of the candidate cells as a target cell for the UE to send a PRACH. In some cases, the operation of this step refers to the following steps. Fig.13 The circuit for sending and / or the code for sending may be executed by the circuit and / or the code.

[0133] In some aspects, the set of candidate cells supports mobility signaling via the PHY layer or MAC layer signaling.

[0134] In some aspects, the method 1100 further includes receiving from the target cell an indication of the timing of the PRACH transmission from the UE. In some cases, the operation of this step refers to the following Fig.13 The circuit for receiving and / or the code for receiving may be executed by the circuit and / or the code.

[0135] In some aspects, the method 1100 further includes sending a TA command based on the timing indication for the UE to apply in the target cell. In some cases, the operation of this step refers to the following Fig.13 The circuit for sending and / or the code for sending may be executed by the circuit and / or the code.

[0136] In some aspects, the DCI indicates the target cell by including the ID of the candidate cell.

[0137] In some aspects, the ID is included in the Candidate Pcell Index field of the DCI.

[0138] In some aspects, the DCI indicates the target cell via the CIF.

[0139] In some aspects, the value of the CIF is associated with the target cell.

[0140] In some aspects, a DCI indicates that a value of the CIF is associated with a target cell if the following conditions exist: the CRC of the DCI is scrambled with a certain RNTI; and bits of the FDRA field of the DCI are set to certain values.

[0141] In one aspect, method 1100 or any aspect related thereto may be performed by an apparatus such as Fig.13 The method 1100 is performed by a communication device 1300 that includes various components operable, configured or adapted to perform the method 1100. The communication device 1300 is described in more detail below.

[0142] Please note that Fig.11 This is merely one example of a method, and other methods including fewer, additional, or alternative steps are also possible consistent with the present disclosure.

[0143] Example Communication Device

[0144] Fig.12 Depicted are aspects of an example communications device 1200. In some aspects, the communications device 1200 is user equipment, such as described above with respect to Figure 1 and Figure 3 The UE 104.

[0145] The communication device 1200 includes a processing system 1205 coupled to a transceiver 1245 (e.g., a transmitter and / or a receiver). The transceiver 1245 is configured to transmit and receive signals for the communication device 1200, such as the various signals described herein, via an antenna 1250. The processing system 1205 may be configured to perform processing functions for the communication device 1200, including processing signals received by the communication device 1200 and / or to be transmitted by it.

[0146] The processing system 1205 includes one or more processors 1210. In various aspects, the one or more processors 1210 may represent one or more of the receive processor 358, the transmit processor 364, the TX MIMO processor 366, and / or the controller / processor 380, as described with respect to FIG. Figure 3The one or more processors 1210 are coupled to the computer readable medium / memory 1225 via the bus 1240. In some aspects, the computer readable medium / memory 1225 is configured to store instructions (e.g., computer executable code) that, when executed by the one or more processors 1210, cause the one or more processors 1210 to perform operations related to Fig.10 The method 1000 or any aspect related thereto is described. Note that reference to a processor performing a function of the communication device 1200 may include one or more processors 1210 performing the function of the communication device 1200.

[0147] In the depicted example, the computer readable medium / memory 1225 stores code (e.g., executable instructions), such as code for receiving 1230 and code for sending 1235. Processing of the code for receiving 1230 and the code for sending 1235 may cause the communication device 1200 to perform operations related to the communication. Fig.10 The method 1000 described herein or any aspect related thereto.

[0148] The one or more processors 1210 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1225, including circuits such as circuits for receiving 1215 and circuits for transmitting 1220. Processing using the circuits for receiving 1215 and the circuits for transmitting 1220 may cause the communication device 1200 to perform operations related to the communication. Fig.10 The method 1000 described herein or any aspect related thereto.

[0149] The various components of the communication device 1200 may provide for performing Fig.10 The components of the method 1000 or any aspect related thereto. For example, the components for sending, transmitting or outputting for sending may include Figure 3 The transceiver 354 and / or antenna 352 and / or Fig.12 The transceiver 1245 and antenna 1250 of the communication device 1200 in FIG. 1 may include Figure 3 The illustrated transceiver 354 and / or antenna 352 and / or Fig.12 The transceiver 1245 and antenna 1250 of the communication device 1200.

[0150] Fig.13 Aspects of an example communications device 1300 are depicted. In some aspects, communications device 1300 is a network entity such as Figure 1 and Figure 3 BS102 or such Figure 2 The decomposed base station in question.

[0151] The communication device 1300 includes a processing system 1305 coupled to a transceiver 1345 (e.g., a transmitter and / or a receiver) and / or a network interface 1355. The transceiver 1345 is configured to transmit and receive signals for the communication device 1300 via an antenna 1350, such as various signals as described herein. The network interface 1355 is configured to transmit and receive signals for the communication device 1300 via a communication link (such as, for example, a signal such as described herein). Figure 2 The processing system 1305 may be configured to perform processing functions of the communication device 1300, including processing signals received by the communication device 1300 and / or to be transmitted by the communication device 1300.

[0152] The processing system 1305 includes one or more processors 1310. In various aspects, the one or more processors 1310 may represent one or more of the receive processor 338, the transmit processor 320, the TX MIMO processor 330, and / or the controller / processor 340, as described with respect to FIG. Figure 3 The one or more processors 1310 are coupled to the computer readable medium / memory 1325 via the bus 1340. In some aspects, the computer readable medium / memory 1325 is configured to store instructions (e.g., computer executable code) that, when executed by the one or more processors 1310, cause the one or more processors 1310 to perform operations related to Fig.11 The method 1100 or any aspect related thereto is described. Note that reference to a processor of the communication device 1300 performing a function may include one or more processors 1310 of the communication device 1300 performing the function.

[0153] In the depicted example, computer readable medium / memory 1325 stores code (e.g., executable instructions), such as code for transmitting 1330 and code for receiving 1335. Processing of code for transmitting 1330 and code for receiving 1335 may cause communication device 1300 to perform operations related to Fig.11 The method 1100 or any aspect related thereto is described.

[0154] The one or more processors 1310 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1325, including circuits such as circuits for transmitting 1315 and circuits for receiving 1320. Processing using the circuits for transmitting 1315 and the circuits for receiving 1320 may cause the communication device 1300 to perform operations related to Fig.11 The method 1100 or any aspect related thereto is described.

[0155] The various components of the communication device 1300 may be provided for performing the following operations: Fig.11 Means for sending, transmitting or outputting for sending may include Figure 3 The illustrated transceiver 332 and / or antenna 334 and / or Fig.13 The transceiver 1345 and antenna 1350 of the communication device 1300 in FIG. 1 may include Figure 3 The illustrated transceiver 332 and / or antenna 334 and / or Fig.13 The transceiver 1345 and antenna 1350 of the communication device 1300 in FIG.

[0156] Sample Clauses

[0157] Specific implementation examples are described in the following numbered clauses:

[0158] Clause 1: A method for wireless communication by a UE, the method comprising: receiving signaling to configure a set of candidate cells for the UE; receiving DCI from a serving cell indicating one of the set of candidate cells as a target cell for sending a PRACH; and sending the PRACH in the target cell.

[0159] Clause 2: The method of clause 1, wherein the set of candidate cells supports mobility signaling via PHY layer or MAC layer signaling.

[0160] Clause 3: A method according to any of clauses 1 and 2, further comprising: receiving a TA command from the serving cell to apply in the target cell.

[0161] Clause 4: A method as described in any of clauses 1 to 3, wherein the DCI indicates the target cell by including an ID of the candidate cell.

[0162] Clause 5: The method of clause 4, wherein the ID is included in a Candidate Pcell Index field of the DCI.

[0163] Clause 6: A method as described in any of clauses 1 to 5, wherein the DCI indicates the target cell via a CIF.

[0164] Clause 7: A method as described in clause 6, wherein the value of the CIF is associated with the target cell.

[0165] Clause 8: A method according to clause 7, wherein the DCI indicates that the value of the CIF is associated with the target cell if the following conditions exist: the CRC of the DCI is scrambled with a certain RNTI; and the bits of the FDRA field of the DCI are set to certain values.

[0166] Clause 9: A method of wireless communication by a network entity, the method comprising: sending signaling to configure a set of candidate cells for a UE; and sending DCI indicating a candidate cell in the set of candidate cells as a target cell for the UE to send a PRACH.

[0167] Clause 10: A method as set forth in clause 9, wherein the set of candidate cells supports mobility signaling via a PHY layer or MAC layer signaling.

[0168] Clause 11: A method according to any of clauses 9 and 10, the method further comprising: receiving from the target cell an indication based on the timing of the PRACH transmission from the UE. Some examples further comprise sending a TA command for the UE to apply in the target cell based on the indication of the timing.

[0169] Clause 12: A method as described in any of clauses 9 to 11, wherein the DCI indicates the target cell by including an ID of the candidate cell.

[0170] Clause 13: The method of clause 12, wherein the ID is included in a Candidate Pcell Index field of the DCI.

[0171] Clause 14: A method as described in any of clauses 9 to 13, wherein the DCI indicates the target cell via a CIF.

[0172] Clause 15: A method as described in clause 14, wherein the value of the CIF is associated with the target cell.

[0173] Clause 16: A method according to clause 15, wherein the DCI indicates that the value of the CIF is associated with the target cell if the following conditions exist: the CRC of the DCI is scrambled with a certain RNTI; and the bits of the FDRA field of the DCI are set to certain values.

[0174] Clause 17: An apparatus, the apparatus comprising: a memory including executable instructions; and a processor configured to execute the executable instructions and cause the apparatus to perform the method of any one of clauses 1 to 16.

[0175] Clause 18: An apparatus comprising means for performing the method according to any one of clauses 1 to 16.

[0176] Clause 19: A non-transitory computer readable medium comprising executable instructions which, when executed by a processor of an apparatus, cause the apparatus to perform the method of any one of clauses 1 to 16.

[0177] Clause 20: A computer program product embodied on a computer readable storage medium, the computer program product comprising code for performing the method according to any one of clauses 1 to 16.

[0178] Additional considerations

[0179] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limited to the scope, applicability or aspects set forth in the claims. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may omit, replace or add various processes or components as appropriate. For example, the described methods may be performed in a different order from the described order, and various actions may be added, omitted or combined. In addition, the features described with respect to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such devices or methods practiced using other structures, functionality, or structures and functionality other than the various aspects of the present disclosure set forth herein or different from the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of the present invention.

[0180] The various illustrative logic blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed using a general purpose processor, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. Although a general purpose processor may be a microprocessor, in an alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC), or any other such configuration.

[0181] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items (including single members). For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0182] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, and the like. Additionally, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Additionally, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0183] The methods disclosed herein include one or more actions for implementing these methods. Method actions can be interchanged with each other without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and / or use of specific actions can be modified without departing from the scope of the claims. In addition, the various operations of the methods described above can be performed by any suitable components that can perform the corresponding functions. These components may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs) or processors.

[0184] The following claims are not intended to be limited to the various aspects shown herein, but should be given the full scope consistent with the language of the claims. Within the claims, unless explicitly stated, reference to an element in the singular form is not intended to mean "one and only one", but "one or more". Unless otherwise specified, the term "some" refers to one or more. Any claim element is not interpreted according to the provisions of 35 U.S.C. § 112 (f) unless the element is explicitly stated using the phrase "parts for...". All structural and functional equivalents of the elements throughout the various aspects described in this disclosure that are known or will be known later to a person of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, regardless of whether such disclosure is explicitly stated in the claims, anything disclosed herein is not intended to be disclosed to the public.

Claims

1. A method for wireless communication by a user equipment (UE), the method comprising: receiving signaling for configuring a group of candidate cells for the UE; receiving, from the serving cell, downlink control information (DCI) indicating one of the set of candidate cells as a target cell for transmitting a physical random access channel (PRACH); as well as The PRACH is sent in the target cell.

2. The method of claim 1, wherein the set of candidate cells supports mobility signaling via a physical (PHY) layer, or a medium access control (MAC) layer signaling. 3 . The method of claim 1 , further comprising receiving a timing adjustment (TA) command from the serving cell to apply in the target cell. The method according to claim 1 , wherein the DCI indicates the target cell by including an ID of the candidate cell. 5 . The method of claim 4 , wherein the ID is included in a candidate primary cell (Pcell) index field of the DCI.

6. The method of claim 1, wherein the DCI indicates the target cell via a carrier indicator field (CIF). The method according to claim 6 , wherein the value of the CIF is associated with the target cell.

8. The method of claim 7, wherein the DCI indicates that the value of the CIF is associated with the target cell if: A cyclic redundancy check (CRC) of the DCI is scrambled with a radio network temporary identifier (RNTI); and The bits of the Frequency Domain Resource Allocation (FDRA) field of the DCI are set to certain values.

9. A method for wireless communication by a network entity, the method comprising: Sending signaling to configure a set of candidate cells for a user equipment (UE); as well as Downlink control information (DCI) is sent indicating one of the candidate cells in the group of candidate cells as a target cell for the UE to send a physical random access channel (PRACH).

10. The method of claim 9, wherein the set of candidate cells supports mobility signaling via a physical (PHY) layer, or a medium access control (MAC) layer signaling.

11. The method according to claim 9, further comprising: receiving, from the target cell, an indication based on the timing of the PRACH transmission from the UE; as well as A timing adjustment (TA) command is sent based on the indication of the timing for application by the UE in the target cell. 12 . The method according to claim 9 , wherein the DCI indicates the target cell by including an ID of the candidate cell.

13. The method of claim 12, wherein the ID is included in a candidate primary cell (Pcell) index field of the DCI.

14. The method of claim 9, wherein the DCI indicates the target cell via a carrier indicator field (CIF). The method according to claim 14 , wherein the value of the CIF is associated with the target cell.

16. The method of claim 15, wherein the DCI indicates that the value of the CIF is associated with the target cell if: A cyclic redundancy check (CRC) of the DCI is scrambled with a radio network temporary identifier (RNTI); and The bits of the Frequency Domain Resource Allocation (FDRA) field of the DCI are set to certain values.

17. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: a memory including computer executable instructions; and a processor configured to execute the computer executable instructions and cause the apparatus to: receiving signaling for configuring a group of candidate cells for the UE; receiving, from the serving cell, downlink control information (DCI) indicating one of the set of candidate cells as a target cell for transmitting a physical random access channel (PRACH); as well as The PRACH is sent in the target cell.

18. The apparatus of claim 17, wherein the set of candidate cells supports mobility signaling via a physical (PHY) layer, or a medium access control (MAC) layer signaling.

19. The apparatus of claim 17, wherein the processor is configured to execute the computer-executable instructions and further cause the apparatus to receive a timing adjustment (TA) command from the serving cell to apply in the target cell.

20. The apparatus according to claim 17, wherein the DCI indicates the target cell by including an ID of the candidate cell.

21. The apparatus of claim 20, wherein the ID is included in a candidate primary cell (Pcell) index field of the DCI.

22. The apparatus of claim 17, wherein the DCI indicates the target cell via a carrier indicator field (CIF).

23. The apparatus of claim 22, wherein the value of the CIF is associated with the target cell.

24. The apparatus of claim 23, wherein the DCI indicates that the value of the CIF is associated with the target cell if: A cyclic redundancy check (CRC) of the DCI is scrambled with a radio network temporary identifier (RNTI); and The bits of the Frequency Domain Resource Allocation (FDRA) field of the DCI are set to certain values.

25. An apparatus for wireless communication at a network entity, the apparatus comprising: a memory including computer executable instructions; and a processor configured to execute the computer executable instructions and cause the apparatus to: Sending signaling to configure a set of candidate cells for a user equipment (UE); as well as Downlink control information (DCI) is sent indicating one candidate cell among the group of candidate cells as a target cell for the UE to send a physical random access channel (PRACH).

26. The apparatus of claim 25, wherein the set of candidate cells supports mobility signaling via a physical (PHY) layer, or a medium access control (MAC) layer signaling.

27. The apparatus of claim 25, wherein the processor is configured to execute the computer executable instructions and further cause the apparatus to: receiving, from the target cell, an indication based on the timing of the PRACH transmission from the UE; and A timing adjustment (TA) command is sent based on the indication of the timing for application by the UE in the target cell.

28. The apparatus according to claim 25, wherein the DCI indicates the target cell by including an ID of the candidate cell.

29. The apparatus of claim 28, wherein the ID is included in a candidate primary cell (Pcell) index field of the DCI.

30. The apparatus of claim 25, wherein the DCI indicates the target cell via a carrier indicator field (CIF).

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