Method, device and system for supporting L1 / L2-based inter-cell mobility

Abstract

The present disclosure describes methods, systems, and devices for configuring inter-cell mobility supporting Layer 1 or Layer 2 signaling (L1 / L2). A method includes a first network node supporting mobility triggering of 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 to be handed over for the UE. Another method comprises: a third network node supporting mobility triggering of a UE from a first network node to a second network node by receiving, by the third network node, a first message for the UE from the first network node, the first message comprising mobility information indicating a list of candidate cells to be handed over for the UE.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications. In particular, the present disclosure relates to methods, devices, and systems for supporting inter-cell mobility based on layer 1 or layer 2 signaling (L1 / L2). Background Art

[0002] Wireless communication technology is driving the world towards an increasingly interconnected and networked society. High-speed and low-latency wireless communications rely on efficient network resource management and allocation between user devices and radio access network nodes (including but not limited to base stations). The next-generation network is expected to provide high-speed, low-latency and ultra-reliable communication capabilities and meet the needs of different industries and users.

[0003] Mobility is one of the important aspects of the rapid development of cellular mobile communication systems. When a user equipment (UE) moves from one cell border to another, it will encounter many problems / difficulties related to cell change. These problems / difficulties may include extended latency, higher signaling overhead and / or long interruption time.

[0004] The present disclosure describes various embodiments that support inter-cell mobility based on layer 1 or layer 2 signaling (L1 / L2), solving at least one of the problems / difficulties discussed above. Various embodiments in the present disclosure can achieve low latency, low overhead, and short interruption time, thereby improving the efficiency and / or performance of wireless communications. Summary of the invention

[0005] The present invention relates to methods, systems and devices for wireless communication, and more specifically, to methods, systems and devices for supporting inter-cell mobility based on layer 1 or layer 2 signaling (L1 / L2). Various embodiments of the present invention can improve resource utilization efficiency, improve latency performance of wireless communication, and / or save energy consumption of user equipment.

[0006] In one embodiment, the present disclosure describes a method for wireless communication. The method includes: a first network node supports mobility triggering of a UE from the first network node to a second network node in the following manner: the first network node sends a first message for the UE to a third network node, the first message including mobility information indicating a list of candidate cells to be handed over to the UE.

[0007] In one embodiment, the present disclosure describes a method for wireless communication. The method includes: a third network node supports a mobility trigger of a UE from a first network node to a second network node in the following manner: the third network node receives a first message for the UE from the first network node, the first message including mobility information indicating a list of candidate cells to be handed over for the UE.

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

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

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

[0011] The above and other aspects and embodiments thereof are described in more detail in the drawings, the description and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0013] Figure 1B shows a schematic diagram of a base station;

[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 flow chart of a wireless communication method is shown;

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

[0018] Figure 5 A flow chart illustrating an exemplary embodiment of wireless communication;

[0019] Figure 6 A flow chart illustrating an exemplary embodiment of wireless communication;

[0020] Figure 7 A flow chart illustrating an exemplary embodiment of wireless communication;

[0021] Figure 8 A flow chart of an exemplary embodiment of wireless communications is shown. DETAILED DESCRIPTION

[0022] The present disclosure will now be described in detail below with reference to the accompanying drawings, which are a part of the present disclosure and show specific examples of embodiments by way of illustration. However, it should be noted that the present disclosure can be implemented in various different forms, and therefore, the subject matter covered or claimed is intended to be interpreted as not being limited to any embodiment set forth below.

[0023] Throughout the specification and claims, terms may have nuanced meanings that are suggested or implied by the context, not just the explicitly stated meanings. Likewise, 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. 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 all or part of embodiments.

[0024] Typically, terms can be understood at least in part based on their use in context. For example, terms such as "and", "or" or "and / or" used herein can include multiple meanings, which can depend at least in part on the context in which the terms are used. Typically, "or" if used in an association list, such as A, B or C, means A, B and C, which are used here for inclusion, and A, B or C, which are used here for exclusion. In addition, the terms "one or more" or "at least one" used herein, at least in part depending on the context, can be used to describe any feature, structure or characteristic in a singular sense, or can be used to describe a combination of features, structures or characteristics in a plural sense. Similarly, terms such as "one", "a kind of" or "the" can be understood to express singular or plural usage, at least in part depending on the context. In addition, the term "based on" or "determined by..." can be understood to not necessarily be intended to express a set of exclusive factors, but can allow the presence of additional factors that are not necessarily explicitly described, which also depends at least in part on the context.

[0025] The present disclosure describes various embodiments that support inter-cell mobility based on layer 1 or layer 2 signaling (L1 / L2).

[0026] Wireless communication technology is driving the world towards an increasingly interconnected and networked society. High-speed and low-latency wireless communications rely on efficient network resource management and allocation between user equipment and radio access network nodes (including but not limited to base stations). The next-generation network is expected to provide high-speed, low-latency and ultra-reliable communication capabilities and meet the needs of different industries and users. Mobility is one of the important aspects of the rapid development of cellular mobile communication systems. When a UE moves from one cell boundary to another, it will encounter many problems / difficulties related to cell changes. These problems / difficulties may include extended latency, higher signaling overhead and / or long interruption time.

[0027] For example, in some embodiments, the serving cell change may be triggered by Layer 3 (L3) measurements and may be accomplished by a reconfiguration triggered by Radio Resource Control (RRC) signaling, wherein the primary cell (PCell) and the primary secondary cell (PSCell) are changed synchronously, and the secondary cell (SCell) is released and added synchronously when applicable. These embodiments may include a full L2 (and / or L1) reset, resulting in longer latency, greater signaling overhead, and / or longer interruption time compared to beam switching mobility. In some embodiments, during the L1 / L2 mobility triggering phase of the intra-CU inter-DU scenario, when the source DU determines the candidate cell to be activated / switched to (e.g., based on the L1 measurement report), it may not be able to notify the CU of the L1 / L2 mobility trigger.

[0028] Various embodiments of the present disclosure include, for intra-CU inter-DU scenarios, when the DU determines the L1 / L2 mobility trigger, a process and signaling for the source DU to notify the CU about the L1 / L2 mobility trigger. Various embodiments of the present disclosure can achieve low latency, low overhead, and short interruption time, thereby improving the efficiency and / or performance of wireless communication.

[0029] Figure 1A An exemplary cellular wireless communication network 100 (also referred to 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 a plurality of base stations 122 and 124. Base station 122 and one or more UE 130 communicate with each other via Over the Air (OTA) wireless communication resources 140. Wireless communication network 100 may be implemented as, for example, a 2G, 3G, 4G / LTE, 5G or 6G cellular communication network. Correspondingly, base stations 122 and 124 may be implemented as 2G base stations, 3G nodeBs, LTE eNBs or 5G New Radio (NR) gNBs. UE 130 may be implemented as a mobile or fixed communication device for accessing wireless communication network 100. One or more UE 130 may 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 assistant equipment and desktop computers. As an alternative to a cellular wireless network environment, RAN 120 and the principles described below may 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 of FIG. 1 , one or more UEs 130 may connect to a base station 122 via an OTA interface 140 and establish a communication session. The communication session between the UE 130 and the base station 122 may 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 some cases, such as when the base station 122 is unavailable or when the UE 130 moves into the coverage of the base station 124, one or more UEs 130 may 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 (DU) 171 and / or 172. The 5G Core Network (5GC) may communicate with the gNB via the NG interface between the 5GC and the gNB. The gNB and another gNB may communicate via the Xn-C interface. The gNB-CU may communicate with one or more gNB-DUs via the F1 interface.

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

[0034] In some embodiments, in order to reduce the handover interruption time and improve mobility reliability (i.e., mobility robustness), conditional handover (CHO) may be proposed. CHO is defined as a handover performed by the UE when an execution condition is met. The UE starts evaluating the execution condition upon receiving the CHO configuration, and stops evaluating the execution condition once the handover is triggered. The CHO configuration includes a candidate PCell configuration generated by a candidate target node and the corresponding execution condition of the candidate cell.

[0035] In some embodiments, in order to improve mobility reliability (i.e., mobility robustness) in the case of a Secondary Node (SN) change or addition of an SN, a Conditional PSCell Addition / Change (CPAC) may be proposed. Similar to CHO, CPAC is defined as having configured CPAC execution conditions that determine when / whether to execute the corresponding PSCell add / change command. Once the CPAC configuration is received, the UE starts evaluating the conditions and executes the CPAC command only when the conditions are met.

[0036] In some implementations, in order to reduce mobility interruption, a handover process based on a dual active protocol stack (DAPS) may be proposed. In a handover process based on DAPS, the UE remains connected to both the source cell and the target cell until the source cell is released after successfully randomly 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 a wireless transmission / reception (Transmitting / Receiving, Tx / Rx) circuit 208 for sending / receiving communications with UE and / or other base stations. The electronic device 200 may also include a network interface circuit 209 for enabling the base station to communicate with other base stations and / or a core network via, for example, optical or wired interconnection, Ethernet and / or other data transmission media / protocols. The electronic device 200 may optionally include an input / output (Input / Output, I / O) interface 206 for communicating with an operator or the like.

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

[0039] Figure 3An example of an electronic device implementing a terminal device 300 (e.g., UE) is shown. UE 300 may be a mobile device, such as a smart phone or a mobile communication module provided in a vehicle. UE 300 may include a communication interface 302, a system circuit 304, an I / O interface 306, a display circuit 308, and a storage device 309. The display circuit may include a user interface 310. System circuit 304 may include any combination of hardware, software, firmware, or other logic / circuits. System circuit 304 may be implemented, for example, with one or more systems on a chip (Systems on a Chip, SoC), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), discrete analog and digital circuits, and other circuits. System circuit 304 may be part of an implementation of any desired function in UE 300. In this regard, the system circuit 304 may include logic that facilitates, for example, decoding and playing music and videos (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 the user interface 310. The user interface 310 and the I / O interface 306 may include a graphical user interface, a touch-sensitive display, tactile feedback or other tactile output, voice or facial recognition input, buttons, switches, speakers, and other user interface elements. Other examples of the I / O interface 306 may include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headphone 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 3, the communication interface 302 may include radio frequency (RF) transmission (Tx) and reception (Rx) circuits 316 that handle the transmission and reception of signals through one or more antennas 314. The communication interface 302 may include one or more transceivers. The transceiver may be a wireless transceiver that includes modulation / demodulation circuits, digital to analog converters (DAC), shaping tables, analog to digital converters (ADC), filters, waveform shapers, filters, preamplifiers, power amplifiers, and / or other logic for transmitting and receiving through one or more antennas or (for some devices) through a physical (e.g., wired) medium. The signals transmitted and received may follow 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, the communication interface 302 may include a transceiver that supports 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 from the 3rd Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE or other partners or standards bodies.

[0041] refer to Figure 3 , the system circuit 304 may include one or more processors 321 and a memory 322. The memory 322 stores, for example, an operating system 324, instructions 326, and parameters 328. The processor 321 is configured to execute the instructions 326 to implement the desired functions of the UE 300. The parameters 328 may provide and specify configuration and operating options for the instructions 326. The memory 322 may also store any BT, WiFi, 3G, 4G, 5G, 6G, or other data that the UE 300 will send or has received through the communication interface 302. In various embodiments, the system power of the UE 300 may be provided by a power storage device such as a battery or a transformer.

[0042] The present disclosure describes various embodiments that support inter-cell mobility based on layer 1 or layer 2 signaling (L1 / L2), which may be implemented in part or in whole in Figures 2 to 3The method is implemented on a network base station and / or user equipment described in the embodiment.

[0043] refer to Figure 4A , the present disclosure describes various embodiments of a method 400 for wireless communication. The method 400 may include step 410, where a first network node supports mobility triggering of a UE from the first network node to a second network node in the following manner: the first network node sends a first message for the UE to a third network node, the first message including mobility information indicating a list of candidate cells to be handed over for the UE.

[0044] refer to Figure 4B , the present disclosure describes various embodiments of a method 450 for wireless communication. The method 450 may include step 460, where a third network node supports mobility triggering of a UE from a first network node to a second network node in the following manner: the third network node receives a first message for the UE from the first network node, the first message including mobility information indicating a list of candidate cells to be handed over for the UE.

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

[0046] In some embodiments, 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 embodiments, the mobility trigger includes a mobility trigger based on layer 1 or layer 2 signaling (L1 / L2 mobility); and the mobility trigger pertains to inter-DU and intra-CU handovers of the UE. Inter-DU handovers may include when the UE moves from one or more cells in a gNB-DU to another one or more cells in another gNB-DU within the same gNB-CU. Intra-DU handovers may include when the UE moves from one or more cells to another one or more cells in the same gNB-DU within the same gNB-CU.

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

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

[0050] In some embodiments, the mobility information includes L1 / L2 mobility information; and / or the L1 / L2 mobility information includes at least one of the following: an L1 / L2 mobility indicator, a list of candidate cells to be switched, an NR physical cell identifier (PCI), an NR cell global identifier (CGI), or an NR frequency. In some embodiments, when the UE has switched to multiple cells, the L1 / L2 mobility information may include multiple PCIs, multiple CGIs, and multiple frequencies.

[0051] In some embodiments, method 400 / 450 may further include: the first network node receives a measurement report from the UE; the first network node determines a list of candidate cells to be switched based on the measurement report; and / or the first network node sends a command to the UE, the command indicating the list of candidate cells to be switched.

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

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

[0054] In some implementations, the UE starts switching to the candidate cell list for switching in the following manner: starting a random access procedure using the candidate cell list for switching.

[0055] In some embodiments, the first message includes a downlink data delivery status frame; and / or the first network node receives a first confirmation message from a third network node, wherein, in response to receiving the first message, the third network node sends the first confirmation 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 the downlink data delivery status frame indicates unsuccessful transmission data of the UE.

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

[0058] In some implementations, the first message is an access success message; and / or a downlink data delivery status frame indicates unsuccessful transmission data of the UE.

[0059] In some embodiments, the first network node receives a first confirmation message from the third network node, wherein, in response to receiving the first message, the third network node sends the first confirmation 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 the downlink data delivery status indicates unsuccessful transmission data of the UE.

[0061] In some embodiments, the first message does not require a confirmation 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 a downlink data delivery status frame.

[0062] In some implementations, the first message is an access success message; and / or the downlink data delivery status indicates unsuccessful transmission data of the UE.

[0063] The present disclosure describes various embodiments with non-limiting examples of supporting inter-cell mobility based on layer 1 or layer 2 signaling (L1 / L2). For non-limiting examples, the source DU may send L1 / L2 mobility information to the CU to notify the CU about the candidate cells to be activated / switched via an F1 interface message (e.g., a UE context modification request message, or an access success message, or other message). The L1 / L2 mobility information may include one or more of the following: L1 / L2 mobility indicator, activation / switching cell list, NR PCI, NR CGI, NR frequency (e.g., NR frequency information IE). In some embodiments, 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 shown, where a 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 can be referred to as intra-CU inter-DU inter-cell mobility. The exemplary embodiment can include some or all of the following steps. The following steps are labeled with step numbers, which are used to label the 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 referred to as "source DU").

[0066] Referring to step 502, the source DU determines a candidate cell to be activated / switched to, for example, based on an L1 measurement report.

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

[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 embodiments, 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 embodiments, the source DU may send a 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 Required message. The UE Context Modification Required message may belong to a Category 1 message, which may require a message receiver to respond to a message sender.

[0070] The L1 / L2 mobility information is used to inform the CU about the candidate cells to be activated / switched. The L1 / L2 mobility information may include at least one of the following: L1 / L2 mobility indicator, activation / switching cell list, NR PCI, NR CGI, NR frequency (e.g., NR frequency information IE). The downlink data delivery status frame is 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 the conflict between L1 / L2 mobility and traditional mobility (i.e., triggered by L3 measurement and the serving cell change completed by RRC signaling).

[0072] Referring to step 505, in response to receiving the UE CONTEXT MODIFY REQUIRED message (as a Category 1 message), the CU responds to the source DU with a UE CONTEXT MODIFY CONFIRM 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 shown, where a 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 can be referred to as intra-CU inter-DU inter-cell mobility. The exemplary embodiment can include some or all of the following steps. The following steps are labeled with step numbers, which are used to label the 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 referred to as "source DU").

[0076] Referring to step 602, the source DU determines a candidate cell to be activated / switched to, for example, based on an L1 measurement report.

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

[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 embodiments, 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 embodiments, the source DU may send a 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 may be an access success message. The access success message may belong to a category 2 message, which does not require the message receiver to respond to the message sender.

[0080] In response to receiving the access success message (as a Category 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 the candidate cells to be activated / switched. L1 / L2 mobility related information may include L1 / L2 mobility indicator, activation / switching cell list, NR PCI, NR CGI, NR frequency (e.g. NR frequency information IE). Downlink data delivery status frame is 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 shown, where a 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 can be referred to as intra-CU inter-DU inter-cell mobility. The exemplary embodiment can include some or all of the following steps. The following steps are labeled with step numbers, which are used to label the 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 referred to as "source DU").

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

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

[0087] Referring to step 704, the source DU sends a first F1 interface message to the gNB-CU (or referred to as "CU"). The first F1 interface message may include L1 / L2 mobility information. In some embodiments, the first F1 interface message may be a UE context modification required message. The UE context modification required message may belong to a category 1 message, which may require the message recipient to respond to the message sender. The L1 / L2 mobility information is used to notify the CU about information about candidate cells to be activated / switched. The L1 / L2 mobility information may include at least one of the following: L1 / L2 mobility indicator, activation / switching cell list, NR PCI, NRCGI, NR frequency (e.g., NR frequency information IE).

[0088] Referring to step 705, in response to receiving the UE CONTEXT MODIFICATION NEEDED 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 referred to as "CU"). The second F1 interface message may include a downlink data delivery status frame. In some embodiments, the second F1 interface message may be an access success message. The access success message may belong to a category 2 message, which does not require the message recipient to respond 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 embodiments, the source DU may send a 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 shown, where a UE 891 can move from a cell operated by a source gNB-DU 892 to another cell operated by a candidate gNB-DU 893. In some embodiments, the source gNB-DU and the candidate gNB-DU can communicate with the same gNB-CU 894, which can be referred to as intra-CU inter-DU inter-cell mobility. The exemplary embodiment can include some or all of the following steps. The following steps are labeled with step numbers, which are used to label the 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 referred to as "source DU").

[0093] Referring to step 802, the source DU determines a candidate cell to be activated / switched to, for example, based on an L1 measurement report.

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

[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 embodiments, the first F1 interface message may be an access success message. The access success message may belong to a category 2 message, which does not require the message receiver to respond to the message sender.

[0096] In response to receiving the access success message (as a Category 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 the candidate cells to be activated / switched. L1 / L2 mobility related information may include L1 / L2 mobility indicator, activation / switching cell list, NR PCI, NR CGI, NR frequency (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 referred to as "CU"). The second F1 interface message may include a downlink data delivery status frame. In some embodiments, the first F1 interface message may be an access success message. 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 embodiments, the source DU may send a 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] The present disclosure describes methods, apparatus, and computer-readable media for wireless communications. The present disclosure addresses the problem of supporting L1 / L2-based inter-cell mobility. The methods, devices, and computer-readable media described in the present disclosure can facilitate the performance of wireless communications by supporting L1 / L2-based inter-cell mobility, thereby improving efficiency and overall performance. The methods, devices, and computer-readable media described in the present disclosure can improve the overall efficiency of wireless communication systems.

[0101] Throughout the specification, references to features, advantages, or similar language do not mean that all features and advantages that can be achieved with the solution are or should be included in any single implementation thereof. Instead, language referring to features and advantages should be understood to mean that a particular feature, advantage, or characteristic described in conjunction with an embodiment is included in at least one embodiment of the solution. Therefore, throughout the specification, discussions of features and advantages and 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 the present solution may be combined in any suitable manner. Based on the description herein, one of ordinary skill in the relevant art will recognize that the present solution may be practiced without one or more specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the present solution.

Claims

1. A method for wireless communication, comprising: The first network node supports mobility triggering of a user equipment UE from the first network node to a second network node in the following manner: The first network node sends a first message for the UE to a third network node, where the first message includes mobility information and indicates a list of candidate cells to be switched for the UE.

2. A method for wireless communication, comprising: The third network node supports mobility triggering of the user equipment UE from the first network node to the second network node in the following manner: The third network node receives a first message for the UE from the first network node, where the first message includes mobility information and indicates a list of candidate cells to be handed over of the UE.

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

4. The method according to any one of claims 1 to 2, wherein: The mobility trigger comprises a mobility trigger based on layer 1 or layer 2 signaling (L1 / L2 mobility); and The mobility triggers inter-DU and intra-CU handovers belonging to the UE.

5. The method according to any one of claims 1 to 2, wherein: The first message belongs to an F1 interface message.

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

7. The method according to any one of claims 1 to 2, wherein: The mobility information includes L1 / L2 mobility information; and The L1 / L2 mobility information includes at least one of the following: an L1 / L2 mobility indicator, the list of candidate cells to be switched, a new wireless NR physical cell identifier PCI, an NR cell global identifier CGI or an NR frequency.

8. The method according to any one of claims 1 to 2, 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 switched according to the measurement report; as well as The first network node sends a command to the UE, where the command indicates the list of candidate cells to be switched.

9. The method according to claim 8, wherein: The measurement report comprises an L1 measurement report; and The command includes an L1 / L2 command, and the L1 / L2 command includes a list of IDs of cells to be switched.

10. The method according to claim 8, wherein: In response to receiving the command, the UE starts switching to the list of candidate cells to be switched.

11. The method according to claim 10, wherein: The UE starts switching to the candidate cell list to be switched in the following manner: The random access process is started using the list of candidate cells to be switched.

12. The method according to any one of claims 1 to 2, wherein: The first message includes a downlink data delivery status frame; and The first network node receives a first confirmation message from the third network node, wherein the third network node sends the first confirmation message to the first network node in response to receiving the first message.

13. The method according to claim 12, 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 unsuccessful transmission data of the UE.

14. The method according to any one of claims 1 to 2, wherein: The first message includes a downlink data delivery status frame; and The first message does not require an acknowledgement message from the third network node.

15. The method according to claim 14, wherein: The first message is an access success message; and The downlink data delivery status frame indicates unsuccessful transmission data of the UE.

16. The method according to any one of claims 1 to 2, wherein: The first network node receives a first confirmation message from the third network node, wherein in response to receiving the first message, the third network node sends the first confirmation message to the second network node; and The first network node sends one of the following to the third network node: Downlink data delivery status frame, or A second message including the downlink data delivery status frame.

17. The method of claim 16, 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 unsuccessful transmission data of the UE.

18. The method according to any one of claims 1 to 2, wherein: The first message does not require an acknowledgement 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 A second message including the downlink data delivery status frame.

19. The method of claim 18, wherein: The first message is an access success message; and The downlink data delivery status indicates unsuccessful transmission data of the UE.

20. 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 19.

21. A computer program product comprising computer readable program medium code stored therein, which, when executed by a processor, causes the processor to perform the method according to any one of claims 1 to 19.

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