Methods, devices, and systems for supporting l1 / l2 based inter-cell mobility

Abstract

The present disclosure describes methods, systems, and devices for configuring support for inter-cell mobility based on Layer 1 or Layer 2 signaling (L1 / L2). One method includes a first network node supporting a mobility trigger for a user equipment (UE) from the first network node to a second network node by the first network node sending a first message for the UE to a third network node, the first message including mobility information indicating a list of candidate cells for the UE to be handed over. Another method includes a third network node supporting a mobility trigger for a UE from a first network node to a second network node by the third network node receiving a first message for the UE from the first network node, the first message including mobility information indicating a list of candidate cells for the UE to be handed over.

Description

Technical Field

[0001] This disclosure generally relates to wireless communications. In particular, this disclosure relates to methods, apparatus, and systems for supporting inter-cell mobility based on Layer 1 or Layer 2 signaling (L1 / L2). Background Technology

[0002] Wireless communication technology is propelling the world towards an increasingly interconnected and networked society. High-speed and low-latency wireless communication relies on efficient network resource management and allocation between user equipment and wireless access network nodes (including but not limited to base stations). Next-generation networks promise to provide high-speed, low-latency, and ultra-reliable communication capabilities, meeting the needs of diverse industries and users.

[0003] Mobility is one of the key aspects of the rapid development of cellular mobile communication systems. When a User Equipment (UE) moves from one cell boundary to another, it encounters many problems and challenges related to cell changes. These problems and challenges may include latency, increased signaling overhead, and / or longer downtime.

[0004] This disclosure describes various embodiments supporting inter-cell mobility based on Layer 1 or Layer 2 signaling (L1 / L2), solving at least one of the problems / challenges discussed above. The various embodiments in this disclosure can achieve low latency, low overhead, and short downtime, thereby improving the efficiency and / or performance of wireless communication. Summary of the Invention

[0005] This document relates to methods, systems, and apparatuses for wireless communication, and more specifically, to methods, systems, and apparatuses for supporting inter-cell mobility based on Layer 1 or Layer 2 signaling (L1 / L2). Various embodiments of this disclosure can improve resource utilization efficiency, enhance latency performance of wireless communication, and / or save power consumption of user equipment.

[0006] In one embodiment, this disclosure describes a method for wireless communication. The method includes: a first network node supporting mobility triggering of a UE from the first network node to a second network node by sending a first message for the UE to a third network node, the first message including mobility information indicating a list of candidate cells for handover of the UE.

[0007] In one embodiment, this disclosure describes a method for wireless communication. The method includes: a third network node supporting mobility triggering of a UE from a first network node to a second network node by the third network node receiving a first message for the UE from the first network node, the first message including mobility information indicating a list of candidate cells for handover to the UE.

[0008] In some other embodiments, an apparatus for wireless communication may include: a memory storing instructions; and processing circuitry communicating with the memory. When the processing circuitry executes the instructions, the processing circuitry is configured to perform the methods described above.

[0009] In some other embodiments, a device for wireless communication may include: a memory storing instructions; and processing circuitry communicating with the memory. When the processing circuitry executes the instructions, the processing circuitry is configured to perform the methods described above.

[0010] In some other embodiments, a computer-readable medium includes instructions that, when executed by a computer, cause the computer to perform the methods described above.

[0011] The above and other aspects and their embodiments are described in more detail in the accompanying drawings, description and claims. Attached Figure Description

[0012] Figure 1A A schematic diagram of a wireless communication system is shown;

[0013] Figure 1B A schematic diagram of the base station is shown;

[0014] Figure 2 An example of a network node is shown;

[0015] Figure 3 An example of a user device is shown;

[0016] Figure 4A A flowchart of the wireless communication method is shown;

[0017] Figure 4B A flowchart of another wireless communication method is shown;

[0018] Figure 5 A flowchart illustrating an exemplary embodiment of wireless communication is shown;

[0019] Figure 6 A flowchart illustrating an exemplary embodiment of wireless communication is shown;

[0020] Figure 7 A flowchart illustrating an exemplary embodiment of wireless communication is shown;

[0021] Figure 8 A flowchart illustrating an exemplary embodiment of wireless communication is shown. Detailed Implementation

[0022] This disclosure will now be described in detail below with reference to the accompanying drawings, which are an integral part of this disclosure and illustrate specific examples of embodiments by way of illustration. However, it should be noted that this disclosure may be implemented in various different forms, and therefore, the subject matter covered or claimed is intended to be construed as not being limited to any of the embodiments set forth below.

[0023] Throughout the specification and claims, terms may have nuanced meanings implied or implied in the context, rather than just explicitly stated meanings. Similarly, the phrases “in one embodiment” or “in some embodiments” as used herein do not necessarily refer to the same embodiment, and the phrases “in another embodiment” or “in other embodiments” as used herein do not necessarily refer to different embodiments. For example, the subject matter intended to be claimed includes exemplary embodiments or combinations of whole or part of embodiments.

[0024] Generally, terms can be understood, at least in part, based on their use in context. For example, terms such as “and,” “or,” or “and / or” as used herein can include a variety of meanings, which can depend at least in part on the context in which they are used. Typically, “or” means A, B, and C when used in an associative list, such as A, B, or C, and here it is used in an inclusive sense, as well as A, B, or C, and here it is used in an exclusive sense. Furthermore, the terms “one or more” or “at least one” as used herein, depending at least in part on the context, can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Similarly, terms such as “a,” “an,” or “the” can be understood to express singular or plural usage, depending at least in part on the context. Moreover, the terms “based on” or “determined by” can be understood to not necessarily be intended to express a set of exclusive factors, but can allow for the presence of additional factors that are not necessarily explicitly described, which also depends at least in part on the context.

[0025] This disclosure describes various embodiments supporting inter-cell mobility based on Layer 1 or Layer 2 signaling (L1 / L2).

[0026] Wireless communication technology is propelling the world towards an increasingly interconnected and networked society. High-speed and low-latency wireless communication relies on efficient network resource management and allocation between user equipment (UE) and radio access network nodes (including but not limited to base stations). Next-generation networks promise to provide high-speed, low-latency, and ultra-reliable communication capabilities, meeting the needs of various industries and users. Mobility is one of the key aspects of the rapid development of cellular mobile communication systems. When a UE moves from one cell boundary to another, it encounters many problems / challenges related to cell changes. These problems / challenges may include latency, increased signaling overhead, and / or longer downtime.

[0027] For example, in some implementations, serving cell changes can be triggered by Layer 3 (L3) measurements and can be accomplished by reconfiguration triggered by Radio Resource Control (RRC) signaling, where the primary cell (PCell) and primary / secondary cell (PSCell) are changed simultaneously, and secondary cells (SCell) are released and added simultaneously, where applicable. These implementations may include a full L2 (and / or L1) reset, resulting in longer latency, higher signaling overhead, and / or longer downtime compared to beam-switching mobility. In some implementations, during the L1 / L2 mobility triggering phase in intra-CU inter-DU scenarios, when the source DU determines the candidate cell to be activated / handed to (e.g., based on an L1 measurement report), it may not be able to notify the CU of the L1 / L2 mobility triggering.

[0028] Various embodiments in this disclosure include, for CU-inter-DU scenarios, procedures and signaling where the source DU notifies the CU of the L1 / L2 mobility triggering process when the DU determines that L1 / L2 mobility has been triggered. These embodiments can achieve low latency, low overhead, and short downtime, thereby improving the efficiency and / or performance of wireless communication.

[0029] Figure 1A An exemplary cellular wireless communication network 100 (also known as a wireless communication system) is shown, which includes a core network 110, a radio access network (RAN) 120, and one or more UEs 130.

[0030] RAN 120 also includes multiple base stations 122 and 124. Base station 122 and one or more UEs 130 communicate with each other via over-the-air (OTA) wireless communication resource 140. Wireless communication network 100 can be implemented as, for example, a 2G, 3G, 4G / LTE, 5G, or 6G cellular communication network. Correspondingly, base stations 122 and 124 can be implemented as 2G base stations, 3G nodeBs, LTE eNBs, or 5G New Radio (NR) gNBs. UE 130 can be implemented as a mobile or fixed communication device for accessing wireless communication network 100. One or more UEs 130 can include, but are not limited to, mobile phones, Internet of Things (IoT) devices, machine-type communications (MTC) devices, laptops, tablets, personal digital assistants, wearable devices, distributed remote sensor devices, roadside assistance equipment, and desktop computers. As an alternative to a cellular wireless network environment, RAN 120 and the principles described below can be implemented as other types of wireless access networks, such as Wi-Fi, Bluetooth, ZigBee, and WiMax networks.

[0031] exist Figure 1A In the exemplary wireless communication system 100, one or more UEs 130 can connect to a base station 122 and establish a communication session via an OTA interface 140. The communication session between the UE 130 and the base station 122 can utilize downlink (DL) transmission resources and / or uplink (UL) transmission resources. The DL transmission resources carry data from the base station 122 to the UE 130, and the UL transmission resources carry data from the UE 130 to the base station 122. In certain situations, such as when the base station 122 is unavailable or when the UE 130 moves to the coverage area of ​​the base station 124, one or more UEs 130 can connect to the base station 122 and establish a communication session.

[0032] refer to Figure 1B The base station (e.g., gNB) 122 may have a control-distributed separation structure, which may include a control unit (CU) 160 and one or more distributed units (DUs) 171 and / or 172. The 5G core network (5GC) can communicate with the gNB via the NG interface between the 5GC and the gNB. The gNB and another gNB can communicate via an Xn-C interface. The gNB-CU can communicate with one or more gNB-DUs via an F1 interface.

[0033] In some implementations, in a CU / DU separated architecture, a gNB-CU is defined as a logical node that hosts the RRC, SDAP, and PDCP protocols of the gNB or the en-gNB, and that controls the operation of one or more gNB-DUs. A gNB-DU is defined as a logical node that hosts the RLC, MAC, and PHY layers of the gNB or en-gNB, and that the operation of this logical node is partially controlled by the gNB-CU. One gNB-DU supports one or more cells. A cell is supported by only one gNB-DU.

[0034] In some implementations, to reduce handover downtime and improve mobility reliability (i.e., mobility robustness), a Conditional Handover (CHO) may be proposed. A CHO is defined as a handover performed by the UE when execution conditions are met. The UE begins evaluating execution conditions upon receiving the CHO configuration and stops evaluating them once the handover is triggered. The CHO configuration includes candidate PCell configurations generated by the candidate target node and the corresponding execution conditions for the candidate cells.

[0035] In some implementations, to improve mobility reliability (i.e., mobility robustness) in the event of changes or additions to the secondary node (SN), a Conditional PSCell Addition / Change (CPAC) can be proposed. Similar to a CHO, a CPAC is defined as having configured CPAC execution conditions that determine when / whether to execute the corresponding PSCell Addition / Change command. Once the CPAC configuration is received, the UE begins evaluating the conditions and executes the CPAC command only if the conditions are met.

[0036] In some implementations, a handover process based on the Dual Active Protocol Stack (DAPS) can be proposed to reduce mobility disruptions. During a DAPS-based handover, the UE maintains simultaneous connections with both the source and target cells until it releases the source cell after successfully accessing the target cell.

[0037] Figure 2An example of an electronic device 200 implementing a network base station is shown. The exemplary electronic device 200 may include wireless transmit / receive (Tx / Rx) circuitry 208 for transmitting / receiving communications with a UE and / or other base stations. The electronic device 200 may also include network interface circuitry 209 for enabling the base station to communicate with other base stations and / or the core network via, for example, optical or wired interconnects, Ethernet, and / or other data transmission media / protocols. The electronic device 200 may optionally include an input / output (I / O) interface 206 for communicating with an operator, etc.

[0038] Electronic device 200 may also include system circuitry 204. System circuitry 204 may include processor 221 and / or memory 222. Memory 222 may include operating system 224, instructions 226, and parameters 228. Instructions 226 may be configured for one or more processors in processor 124 to perform the functions of a network node. Parameters 228 may include parameters that support the execution of instructions 226. For example, parameters may include network protocol settings, bandwidth parameters, radio frequency mapping allocation, and / or other parameters.

[0039] Figure 3An example of an electronic device implementing a terminal device 300 (e.g., a UE) is shown. The UE 300 may be a mobile device, such as a smartphone or a mobile communication module located in a vehicle. The UE 300 may include a communication interface 302, system circuitry 304, I / O interface 306, display circuitry 308, and storage device 309. The display circuitry may include a user interface 310. The system circuitry 304 may include any combination of hardware, software, firmware, or other logic / circuit. The system circuitry 304 may be implemented using, for example, one or more systems on a chip (SoC), application-specific integrated circuits (ASICs), discrete analog and digital circuits, and other circuits. The system circuitry 304 may be part of an implementation of any desired functionality in the UE 300. In this regard, system circuitry 304 may include logic that facilitates, for example, decoding and playing music and video (e.g., MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback); running applications; accepting user input; saving and retrieving application data; establishing, maintaining, and terminating cellular phone calls or data connections, such as internet connections; establishing, maintaining, and terminating wireless network connections, Bluetooth connections, or other connections; and displaying relevant information on user interface 310. User interface 310 and I / O interface 306 may include a graphical user interface, a touch-sensitive display, haptic feedback or other haptic outputs, voice or facial recognition inputs, buttons, switches, speakers, and other user interface elements. Other examples of I / O interface 306 may include a microphone, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headset and microphone input / output jacks, Universal Serial Bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors), and other types of inputs.

[0040] refer to Figure 3The communication interface 302 may include radio frequency (RF) transmit (Tx) and receive (Rx) circuitry 316, which processes the transmission and reception of signals via one or more antennas 314. The communication interface 302 may include one or more transceivers. The transceiver may be a wireless transceiver, including modulation / demodulation circuitry, a digital-to-analog converter (DAC), a shaping table, an analog-to-digital converter (ADC), filters, waveform shapers, filters, preamplifiers, power amplifiers, and / or other logic for transmission and reception via one or more antennas or (for some devices) via a physical (e.g., wired) medium. The transmitted and received signals may conform to any of a variety of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), frequency channels, bit rates, and encodings. As a specific example, communication interface 302 may include a transceiver supporting transmission and reception under 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High-Speed ​​Packet Access (HSPA)+, 4G / Long Term Evolution (LTE), 5G standards, and / or 6G standards. However, the techniques described below are applicable to other wireless communication technologies, whether originating from the 3rd Generation Partnership Project (3GPP), the GSM Association, 3GPP2, IEEE, or other partners or standards bodies.

[0041] refer to Figure 3 System circuitry 304 may include one or more processors 321 and memory 322. Memory 322 stores, for example, an operating system 324, instructions 326, and parameters 328. Processor 321 is configured to execute instructions 326 to implement the desired functions of UE 300. Parameters 328 can provide and specify configuration and operational options for instructions 326. Memory 322 may also store any BT, WiFi, 3G, 4G, 5G, 6G, or other data that UE 300 will send or has received via communication interface 302. In various embodiments, system power for UE 300 may be provided by power storage devices such as batteries or transformers.

[0042] This disclosure describes various embodiments supporting inter-cell mobility based on Layer 1 or Layer 2 signaling (L1 / L2), which may be partially or wholly based on… Figures 2 to 3Implemented on the network base stations and / or user equipment described herein.

[0043] refer to Figure 4A This disclosure describes various embodiments of a method 400 for wireless communication. Method 400 may include step 410, in which a first network node supports mobility triggering of a UE from the first network node to a second network node by sending a first message for the UE to a third network node, the first message including mobility information indicating a list of candidate cells for handover to the UE.

[0044] refer to Figure 4B This disclosure describes various embodiments of a method 450 for wireless communication. Method 450 may include step 460, in which a third network node supports mobility triggering of a UE from a first network node to a second network node by receiving a first message for the UE from the first network node, the first message including mobility information indicating a list of candidate cells for handover to the UE.

[0045] In various embodiments and / or implementations of this disclosure, a network node may be referred to as a network element.

[0046] In some implementations, the first network node includes a source distributed unit (gNB-DU) of the base station; the second network node includes a candidate gNB-DU; and the third network node includes a control unit (gNB-CU) of the base station.

[0047] In some implementations, mobility triggering includes mobility (L1 / L2 mobility) triggering based on Layer 1 or Layer 2 signaling; and mobility triggering pertains to inter-DU and intra-CU handovers of the UE. Inter-DU handovers may include situations where the UE moves from one or more cells in a gNB-DU to one or more cells in another gNB-DU within the same gNB-CU. Intra-DU handovers may include situations where the UE moves from one or more cells to one or more cells in the same gNB-DU within the same gNB-CU.

[0048] In some implementations, the first message belongs to the F1 interface message.

[0049] In some implementations, the F1 interface message includes at least one of the following: a UE context modification request message or an access success message.

[0050] In some implementations, mobility information includes L1 / L2 mobility information; and / or L1 / L2 mobility information includes at least one of the following: L1 / L2 mobility indicators, a list of candidate cells for handover, an NR Physical Cell Identifier (PCI), an NR Cell Global Identifier (CGI), or an NR frequency. In some implementations, when the UE has already handed over to multiple cells, the L1 / L2 mobility information may include multiple PCIs, multiple CGIs, and multiple frequencies.

[0051] In some implementations, method 400 / 450 may further include: a first network node receiving a measurement report from the UE; the first network node determining a list of candidate cells to be handed over based on the measurement report; and / or the first network node sending a command to the UE indicating the list of candidate cells to be handed over.

[0052] In some implementations, the measurement report includes an L1 measurement report; and / or the command includes an L1 / L2 command that includes a list of cell IDs to be handed over.

[0053] In some implementations, in response to receiving a command, the UE begins to switch to the list of candidate cells to be handed over.

[0054] In some implementations, the UE begins handover to a list of candidate cells by initiating a random access procedure using the list of candidate cells.

[0055] In some implementations, the first message includes a downlink data delivery status frame; and / or the first network node receives a first acknowledgment message from the third network node, wherein, in response to receiving the first message, the third network node sends the first acknowledgment message to the first network node.

[0056] In some implementations, the first message is a UE context modification request message; the first confirmation message is a UE context modification confirmation message; and / or a downlink data delivery status frame indicating that the UE has failed to transmit data.

[0057] In some implementations, the first message includes a downlink data delivery status frame; and / or the first message does not require an acknowledgment message from a third network node.

[0058] In some implementations, the first message is an access success message; and / or a downlink data delivery status frame indicating that the UE has failed to transmit data.

[0059] In some implementations, the first network node receives a first acknowledgment message from the third network node, wherein, in response to receiving the first message, the third network node sends the first acknowledgment message to the second network node; and / or the first network node sends one of the following to the third network node: a downlink data delivery status frame, or a second message including a downlink data delivery status frame.

[0060] In some implementations, the first message is a UE context modification request message; the first confirmation message is a UE context modification confirmation message; and / or a downlink data delivery status indicating that the UE has failed to transmit data.

[0061] In some implementations, the first message does not require an acknowledgment message from the third network node; and / or the first network node sends one of the following to the third network node: a downlink data delivery status frame, and / or a second message including the downlink data delivery status frame.

[0062] In some implementations, the first message is an access success message; and / or a downlink data delivery status indicating that the UE has failed to transmit data.

[0063] This disclosure describes various embodiments with non-limiting examples of inter-cell mobility supporting Layer 1 or Layer 2 signaling (L1 / L2). For non-limiting examples, the source DU may send L1 / L2 mobility information to the CU via an F1 interface message (e.g., a UE context modification request message, access success message, or other message) to inform the CU about candidate cells to be activated / handover. The L1 / L2 mobility information may include one or more of the following: L1 / L2 mobility indicator, list of activated / handover cells, NR PCI, NR CGI, NR frequency (e.g., NR frequency information IE). In some implementations, the source DU may also send a downlink data delivery status frame via the same (or another) F1 interface message to notify the CU of downlink data that was not successfully transmitted to the UE.

[0064] Figure 5 An exemplary embodiment supporting L1 / L2-based inter-DU inter-cell mobility is illustrated, wherein UE 591 can move from a cell operated by a source gNB-DU 592 to another cell operated by a candidate gNB-DU 593. In some embodiments, the source gNB-DU and the candidate gNB-DU can communicate with the same gNB-CU 594, which may be referred to as intra-CU inter-DU inter-cell mobility. The exemplary embodiment may include some or all of the following steps. The steps are labeled with step numbers, which are used to identify steps and do not impose any restrictions on the order / sequence of the steps.

[0065] Referring to step 501, the UE sends an L1 measurement report to the source gNB-DU (or "source DU").

[0066] Referring to step 502, the source DU determines, for example, the candidate cells to be activated / handed over based on the L1 measurement report.

[0067] Referring to step 503, the source DU sends an L1 / L2 command to indicate to the UE the candidate cell to be activated / handed over.

[0068] Referring to step 504, the source DU sends an F1 interface message to the gNB-CU (or "CU"). The F1 interface message may include L1 / L2 mobility information and a downlink data delivery status frame. In some implementations, the source DU may send two F1 interface messages to the gNB-CU instead of a single F1 interface message as shown in step 504: the first F1 interface message may include L1 / L2 mobility information; and the second F1 interface message may include a downlink data delivery status frame. In some implementations, the source DU may send the downlink data delivery status frame directly to the CU without including it in the F1 interface message; and / or in response to directly receiving the downlink data delivery status frame, the CU may not need to send a response in response to the received downlink data delivery status frame.

[0069] In some implementations, the F1 interface message may be a UE context modification request message. A UE context modification request message may belong to Category 1 messages, which may require a response from the message receiver to the message sender.

[0070] L1 / L2 mobility information is used to inform the CU about candidate cells to be activated / handed over. L1 / L2 mobility information may include at least one of the following: L1 / L2 mobility indicator, list of activated / handed-over cells, NR PCI, NR CGI, NR frequency (e.g., NR frequency information IE). Downlink data delivery status frames are used to notify the CU of downlink data that was not successfully transmitted to the UE.

[0071] The benefits of the source DU notifying the gNB-CU of L1 / L2 mobility information include that the CU knows that the L1 / L2 mobility trigger determined by the DU can effectively avoid conflicts between L1 / L2 mobility and traditional mobility (i.e., triggered by L3 measurement and served cell change completed by RRC signaling).

[0072] Referring to step 505, in response to receiving the UE context modification request message (as a category 1 message), the CU responds to the source DU with a UE context modification confirmation message.

[0073] Referring to step 506, the UE activates / accesses the target cell, for example, via a random access procedure.

[0074] Figure 6 Another exemplary embodiment supporting L1 / L2-based inter-DU inter-cell mobility is illustrated, wherein UE 691 can move from a cell operated by a source gNB-DU 692 to another cell operated by a candidate gNB-DU 693. In some embodiments, the source gNB-DU and the candidate gNB-DU can communicate with the same gNB-CU 694, which may be referred to as intra-CU inter-DU inter-cell mobility. Exemplary embodiments may include some or all of the following steps. These steps are labeled with step numbers, which are used to identify steps and do not impose any restrictions on the order / sequence of the steps.

[0075] Referring to step 601, the UE sends an L1 measurement report to the source gNB-DU (or "source DU").

[0076] Referring to step 602, the source DU determines, for example, the candidate cells to be activated / handed over based on the L1 measurement report.

[0077] Referring to step 603, the source DU sends an L1 / L2 command to indicate to the UE the candidate cell to be activated / handed over.

[0078] Referring to step 604, the source DU sends an F1 interface message to the gNB-CU (or "CU"). The F1 interface message may include L1 / L2 mobility information and a downlink data delivery status frame. In some implementations, the source DU may send two F1 interface messages to the gNB-CU instead of a single F1 interface message as shown in step 604: the first F1 interface message may include L1 / L2 mobility information; and the second F1 interface message may include a downlink data delivery status frame. In some implementations, the source DU may send the downlink data delivery status frame directly to the CU without including it in the F1 interface message; and / or in response to directly receiving the downlink data delivery status frame, the CU may not need to send a response in response to the received downlink data delivery status frame.

[0079] In some implementations, the F1 interface message can be an access success message. An access success message can belong to category 2 messages, which do not require a response from the message receiver to the message sender.

[0080] Upon receiving an access success message (as a Class 2 message), the CU does not send any response message to the source DU.

[0081] L1 / L2 mobility information is used to inform the CU about candidate cells to be activated / handed over. L1 / L2 mobility-related information may include L1 / L2 mobility indicators, a list of activated / handed-over cells, NR PCI, NR CGI, and NR frequencies (e.g., NR frequency information IE). Downlink data delivery status frames are used to notify the CU of downlink data that was not successfully transmitted to the UE.

[0082] Referring to step 605, the UE activates / accesses the target cell, for example, via a random access procedure.

[0083] Figure 7 Another exemplary embodiment supporting L1 / L2-based inter-DU inter-cell mobility is illustrated, wherein UE 791 can move from a cell operated by a source gNB-DU 792 to another cell operated by a candidate gNB-DU 793. In some embodiments, the source gNB-DU and the candidate gNB-DU can communicate with the same gNB-CU 794, which may be referred to as intra-CU inter-DU inter-cell mobility. Exemplary embodiments may include some or all of the following steps. These steps are labeled with step numbers, which are used to identify steps and do not impose any restrictions on the order / sequence of the steps.

[0084] Referring to step 701, the UE sends an L1 measurement report to the source gNB-DU (or "source DU").

[0085] Referring to step 702, the source DU determines, for example, the candidate cell to be activated / handed over based on the L1 measurement report.

[0086] Referring to step 703, the source DU sends an L1 / L2 command to indicate to the UE the candidate cell to be activated / handed over.

[0087] Referring to step 704, the source DU sends a first F1 interface message to the gNB-CU (or "CU"). The first F1 interface message may include L1 / L2 mobility information. In some implementations, the first F1 interface message may be a UE context modification request message. A UE context modification request message may be a Category 1 message, which may require a response from the message receiver to the message sender. The L1 / L2 mobility information is used to inform the CU about candidate cells to be activated / handover. The L1 / L2 mobility information may include at least one of the following: L1 / L2 mobility indicator, list of activated / handover cells, NR PCI, NRCGI, NR frequency (e.g., NR frequency information IE).

[0088] Referring to step 705, in response to receiving a UE context modification request message (as a category 1 message), the CU responds to the source DU by sending a UE context modification confirmation message.

[0089] Referring to step 706, the source DU sends a second F1 interface message to the gNB-CU (or "CU"). The second F1 interface message may include a downlink data delivery status frame. In some implementations, the second F1 interface message may be an access success message. An access success message may belong to category 2 messages, which do not require a response from the message receiver to the message sender. The downlink data delivery status frame is used to notify the CU of downlink data that was not successfully transmitted to the UE. In some implementations, the source DU may send the downlink data delivery status frame directly to the CU without including it in the F1 interface message; and / or in response to directly receiving the downlink data delivery status frame, the CU may not need to send a response in response to the received downlink data delivery status frame.

[0090] Referring to step 707, the UE activates / accesses the target cell, for example, via a random access procedure.

[0091] Figure 8 Another exemplary embodiment supporting L1 / L2-based inter-DU inter-cell mobility is illustrated, wherein UE 891 can move from a cell operated by source gNB-DU 892 to another cell operated by candidate gNB-DU 893. In some embodiments, the source gNB-DU and candidate gNB-DU can communicate with the same gNB-CU 894, which may be referred to as intra-CU inter-DU inter-cell mobility. Exemplary embodiments may include some or all of the following steps. These steps are labeled with step numbers, which are used to identify steps and do not impose any restrictions on the order / sequence of the steps.

[0092] Referring to step 801, the UE sends an L1 measurement report to the source gNB-DU (or "source DU").

[0093] Referring to step 802, the source DU determines, for example, the candidate cells to be activated / handed over based on the L1 measurement report.

[0094] Referring to step 803, the source DU sends an L1 / L2 command to indicate to the UE the candidate cell to be activated / handed over.

[0095] Referring to step 804, the source DU sends a first F1 interface message to the gNB-CU (or "CU"). The first F1 interface message may include L1 / L2 mobility information. In some implementations, the first F1 interface message may be an access success message. Access success messages may belong to category 2 messages, which do not require a response from the message receiver to the message sender.

[0096] Upon receiving an access success message (as a Class 2 message), the CU does not send any response message to the source DU.

[0097] L1 / L2 mobility information is used to inform the CU about candidate cells to be activated / handover. L1 / L2 mobility-related information may include L1 / L2 mobility indicators, a list of activated / handover cells, NR PCI, NR CGI, and NR frequencies (e.g., NR frequency information IE).

[0098] Referring to step 805, the source DU sends a second F1 interface message to the gNB-CU (or "CU"). The second F1 interface message may include a downlink data delivery status frame. In some implementations, the first F1 interface message may be an access success message. The downlink data delivery status frame is used to notify the CU that downlink data was not successfully transmitted to the UE. In some implementations, the source DU may send the downlink data delivery status frame directly to the CU without including it in the F1 interface message; and / or in response to directly receiving the downlink data delivery status frame, the CU may not need to send a response in response to the received downlink data delivery status frame.

[0099] Referring to step 806, the UE activates / accesses the target cell, for example, via a random access procedure.

[0100] This disclosure describes methods, apparatus, and computer-readable media for wireless communication. This disclosure addresses the problem of supporting L1 / L2-based inter-cell mobility. The methods, apparatus, and computer-readable media described in this disclosure can improve the performance of wireless communication by supporting L1 / L2-based inter-cell mobility, thereby improving efficiency and overall performance. The methods, apparatus, and computer-readable media described in this disclosure can improve the overall efficiency of wireless communication systems.

[0101] Throughout this specification, references to features, advantages, or similar language do not imply that all features and advantages achievable with this solution are included or should be included in any single implementation thereof. Rather, language relating to features and advantages should be understood to mean that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of this solution. Therefore, throughout this specification, discussions of features and advantages, as well as similar language, may, but do not necessarily, refer to the same embodiment.

[0102] Furthermore, in one or more embodiments, the described features, advantages, and characteristics of this solution can be combined in any suitable manner. Based on the description herein, those skilled in the art will recognize that this solution can be practiced without one or more specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of this solution.

Claims

1. A method for wireless communication, comprising: The first network node supports mobility triggering of the user equipment (UE) from the first network node to the second network node in the following ways: The first network node sends a first message to the third network node for the UE. The first message includes mobility information indicating the list of candidate cells to be handed over to the UE, wherein: the mobility information includes L1 / L2 mobility information; and the L1 / L2 mobility information includes at least one of the following: L1 / L2 mobility indicator, the list of candidate cells to be handed over, new radio NR physical cell identifier (PCI), NR cell global identifier (CGI), or NR frequency.

2. The method according to claim 1, wherein: The first network node includes the source distributed unit gNB-DU of the base station; The second network node includes candidate gNB-DU; and The third network node includes the control unit gNB-CU of the base station.

3. The method according to claim 1, wherein: The mobility triggering includes mobility (L1 / L2 mobility) triggering based on Layer 1 or Layer 2 signaling; and The mobility triggering pertains to the UE's inter-DU and intra-CU handover.

4. The method according to claim 1, wherein: The first message belongs to the F1 interface message.

5. The method according to claim 4, wherein: The F1 interface message includes at least one of the following: UE context modification request message or access success message.

6. The method according to claim 1, further comprising: The first network node receives a measurement report from the UE; The first network node determines the list of candidate cells to be handed over based on the measurement report; as well as The first network node sends a command to the UE, the command indicating the list of candidate cells to be handed over.

7. The method according to claim 6, wherein: The measurement report includes the L1 measurement report; and The commands include L1 / L2 commands, which include a list of cell IDs to be switched over.

8. The method according to claim 6, wherein: In response to receiving the command, the UE begins to switch to the list of candidate cells to be handed over.

9. The method according to claim 8, wherein: The UE begins handover to the candidate cell list in the following manner: The random access procedure is initiated using the list of candidate cells to be handed over.

10. The method according to claim 1, wherein: The first message includes a downlink data delivery status frame; and The first network node receives a first acknowledgment message from the third network node in response to the first message.

11. The method of claim 10, wherein: The first message is a UE context modification request message; The first confirmation message is a UE context modification confirmation message; and The downlink data delivery status frame indicates that the UE has failed to transmit data.

12. The method according to claim 1, wherein: The first message includes a downlink data delivery status frame; and The first message does not require an acknowledgment message from the third network node.

13. The method according to claim 12, wherein: The first message is a successful access message; and The downlink data delivery status frame indicates that the UE has failed to transmit data.

14. The method according to claim 1, wherein: The first network node receives from the third network node a first acknowledgment message sent by the third network node in response to the first message; and The first network node sends one of the following to the third network node: Downlink data delivery status frame, or The second message includes the downlink data delivery status frame.

15. The method of claim 14, wherein: The first message is a UE context modification request message; The first confirmation message is a UE context modification confirmation message; and The downlink data delivery status indicates that the UE has failed to transmit data.

16. The method according to claim 1, wherein: The first message does not require an acknowledgment message from the third network node; and The first network node sends one of the following to the third network node: Downlink data delivery status frame, or The second message includes the downlink data delivery status frame.

17. The method of claim 16, wherein: The first message is a successful access message; and The downlink data delivery status indicates that the UE has failed to transmit data.

18. A method for wireless communication, comprising: The third network node supports user equipment (UE) mobility triggering from the first network node to the second network node in the following ways: The third network node receives a first message for the UE from the first network node. The first message includes mobility information indicating a list of candidate cells for handover of the UE, wherein: the mobility information includes L1 / L2 mobility information; and the L1 / L2 mobility information includes at least one of the following: L1 / L2 mobility indicator, the list of candidate cells for handover, new radio NR physical cell identifier (PCI), NR cell global identifier (CGI), or NR frequency.

19. The method of claim 18, wherein: The first network node includes the source distributed unit gNB-DU of the base station; The second network node includes candidate gNB-DU; and The third network node includes the control unit gNB-CU of the base station.

20. The method of claim 18, wherein: The mobility triggering includes mobility (L1 / L2 mobility) triggering based on Layer 1 or Layer 2 signaling; and The mobility triggering pertains to the UE's inter-DU and intra-CU handover.

21. The method according to claim 18, wherein: The first message belongs to the F1 interface message.

22. The method according to claim 21, wherein: The F1 interface message includes at least one of the following: UE context modification request message or access success message.

23. The method of claim 18, wherein: The list of candidate cells to be handed over is determined by the first network node based on the measurement report received from the UE, and The list of candidate cells to be handed over is also included in the command sent by the first network node to the UE.

24. The method according to claim 23, wherein: The measurement report includes the L1 measurement report; and The commands include L1 / L2 commands, which include a list of cell IDs to be switched over.

25. The method according to claim 23, wherein: In response to receiving the command, the UE begins to switch to the list of candidate cells to be handed over.

26. The method of claim 25, wherein: The UE begins handover to the candidate cell list in the following manner: The random access procedure is initiated using the list of candidate cells to be handed over.

27. The method according to claim 18, wherein: The first message includes a downlink data delivery status frame; and In response to receiving the first message, the third network node sends a first confirmation message to the first network node.

28. The method of claim 27, wherein: The first message is a UE context modification request message; The first confirmation message is a UE context modification confirmation message; and The downlink data delivery status frame indicates that the UE has failed to transmit data.

29. The method according to claim 18, wherein: The first message includes a downlink data delivery status frame; and The first message does not require an acknowledgment message from the third network node.

30. The method according to claim 29, wherein: The first message is a successful access message; and The downlink data delivery status frame indicates that the UE has failed to transmit data.

31. The method according to claim 18, wherein: In response to receiving the first message, the third network node sends a first confirmation message to the first network node; and The third network node receives one of the following from the first network node: Downlink data delivery status frame, or The second message includes the downlink data delivery status frame.

32. The method according to claim 31, wherein: The first message is a UE context modification request message; The first confirmation message is a UE context modification confirmation message; and The downlink data delivery status indicates that the UE has failed to transmit data.

33. The method according to claim 18, wherein: The first message does not require an acknowledgment message from the third network node; and The third network node receives one of the following from the first network node: Downlink data delivery status frame, or The second message includes the downlink data delivery status frame.

34. The method according to claim 33, wherein: The first message is a successful access message; and The downlink data delivery status indicates that the UE has failed to transmit data.

35. A wireless communication device, comprising a processor and a memory, wherein, The processor is configured to read code from the memory and execute the method according to any one of claims 1 to 34.

36. A computer program product comprising computer-readable program medium code stored therein, the computer-readable program medium code, when executed by a processor, causing the processor to perform the method according to any one of claims 1 to 34.

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