UE and UE Method

Abstract

The embodiments of the present disclosure relate to a communication method, an apparatus, and a computer-readable medium. A terminal device receives lower layer signaling from a first network device, indicating a cell change or addition to a cell of a second network device and indicating a TCI state of the cell. The terminal device determines an RS associated with the TCI state, and performs an RA procedure for the cell change or addition based on the RS. This can reduce the delay of the mobility procedure based on L1 / L2.

Description

[Technical field]

[0001] TECHNICAL FIELD Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to a method, apparatus, and computer storage medium for communication based on lower layer signaling. [Background technology]

[0002] When a User Equipment (UE) moves from the coverage area of ​​one cell to the coverage area of ​​another cell, a serving cell change, addition, or release needs to be performed. Currently, the serving cell change, addition, or release is triggered by Layer 3 (L3) measurements and performed by Radio Resource Control (RRC) signaling that triggers reconfiguration with synchronization for Primary Cell (PCell) and Primary Secondary Cell (PSCell) changes. In all cases, Layer 2 (L2) and Layer 1 (L1) are fully reset, resulting in higher latency, higher overhead, and longer interruption times compared to beam-switched mobility.

[0003] To address the above challenges, several solutions based on lower layer signaling, such as Layer 1 (L1) and Layer 2 (L2) signaling, have been proposed. In one solution, data transmission is performed by changing the serving cell upon receipt of lower layer signaling, also known as L1 / L2-based mobility, which can reduce delay, overhead, and downtime. However, there is still a lack of development on the implementation details of L1 / L2-based mobility procedures. Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, embodiments of the present disclosure relate to a method, apparatus, and computer storage medium for communication based on lower layer signaling. [Means for solving the problem]

[0005] A first aspect provides a method of communication, comprising: receiving, in a terminal device, lower layer signaling from a first network device indicating a change or addition of a cell to a cell of a second network device and indicating a transmission configuration indicator state of the cell, determining a reference signal associated with the transmission configuration indicator state, and performing a random access procedure for the change or addition of the cell based on the reference signal.

[0006] A second aspect provides a method of communication, the method including: receiving, in a terminal device, lower layer signaling from a first network device, indicating a cell change or addition to a cell of a second network device and indicating a transmission configuration indicator state of the cell, performing a random access procedure for the cell change or addition, and determining, after the random access procedure is completed, that a demodulation reference signal antenna port for receiving a physical downlink control channel is quasi co-located with a reference signal associated with the transmission configuration indicator state.

[0007] A third aspect provides a method of communication, the method including: receiving, in a terminal device, a random access configuration from a network device, the random access configuration being dedicated to changing or adding a cell based on lower layer signaling; and, in response to receiving the lower layer signaling, changing or adding the cell based on the random access configuration.

[0008] A fourth aspect provides a method of communication, the method including: determining, in a terminal device, whether a radio link failure report is triggered by a failure of a lower layer signaling based handover, and sending, according to a determination that the radio link failure report is triggered by a failure of the lower layer signaling based handover, to a network device, a radio link failure report including an indication that a final handover is the lower layer signaling based handover.

[0009] A fifth aspect provides a method of communication, the method including: transmitting, in a first network device, lower layer signaling to a terminal device, indicating a change or addition of a cell to a cell of a second network device and indicating a transmission configuration indicator state of the cell, determining a reference signal associated with the transmission configuration indicator state, and performing a random access procedure for the change or addition of the cell based on the reference signal.

[0010] A sixth aspect provides a method of communication, the method including: transmitting, in a first network device, lower layer signaling to a terminal device, indicating a change or addition of a cell to a cell of a second network device and indicating a transmission configuration indicator state of the cell, performing a random access procedure for the change or addition of the cell, and determining, after the random access procedure is completed, that a demodulation reference signal antenna port for a physical downlink control channel transmission is quasi-co-located with a reference signal associated with the transmission configuration indicator state.

[0011] A seventh aspect provides a method of communication, the method including: generating, in a first network device, a random access configuration dedicated to changing or adding a cell based on lower layer signaling; and transmitting the random access configuration to a terminal device.

[0012] An eighth aspect provides a method of communication, the method including: receiving, in a network device, a radio link failure report from a terminal device, the radio link failure report including an indication that a final handover is a lower layer signaling based handover; and adjusting parameters of the lower layer signaling based handover.

[0013] A ninth aspect provides a terminal device, the terminal device including a processor configured to execute the method according to any one of the first to fourth aspects of the present disclosure.

[0014] A tenth aspect provides a network device, comprising a processor configured to execute the method according to any one of the fifth to eighth aspects of the present disclosure.

[0015] An eleventh aspect provides a computer-readable medium having stored thereon instructions that, when executed by at least one processor, cause the at least one processor to perform a method according to any of the first to fourth aspects of the present disclosure.

[0016] A twelfth aspect provides a computer-readable medium having stored thereon instructions that, when executed by at least one processor, cause the at least one processor to perform a method according to any of the fifth to eighth aspects of the present disclosure.

[0017] Other features of the present disclosure will be more readily understood from the following detailed description. [Brief description of the drawings]

[0018] The above and other objects, features and advantages of the present disclosure will become more apparent through detailed description of several embodiments with reference to the accompanying drawings.

[0019] [Figure 1A] FIG. 1 illustrates an example of a communications network in which some embodiments of the present disclosure may be implemented.

[0020] [Figure 1B] FIG. 2 is a schematic diagram illustrating network protocol layer entities that may be established for a user plane (UP) protocol stack in an apparatus according to some embodiments of the present disclosure.

[0021] [Figure 1C] FIG. 2 is a schematic diagram illustrating network protocol layer entities that may be established for a control plane (CP) protocol stack in an apparatus according to some embodiments of the present disclosure.

[0022] [Figure 1D] FIG. 1 is a schematic diagram illustrating a central unit (CU) / distributed unit (DU) architecture in which some embodiments of the present disclosure may be implemented.

[0023] [Figure 1E] FIG. 2 is a schematic diagram illustrating a process of L1 / L2 based mobility in which some embodiments of the present disclosure may be implemented.

[0024] [Diagram 2] FIG. 2 is a schematic diagram illustrating a process of performing an RA procedure in L1 / L2-based mobility according to an embodiment of the present disclosure.

[0025] [Diagram 3] FIG. 13 is a schematic diagram illustrating another process for performing an RA procedure in L1 / L2-based mobility according to an embodiment of the present disclosure.

[0026] [Figure 4] FIG. 2 is a schematic diagram illustrating a process of performing an L1 / L2 based mobility procedure according to an embodiment of the present disclosure.

[0027] [Diagram 5] FIG. 2 is a schematic diagram illustrating a process of Radio Link Failure (RLF) reporting for L1 / L2-based handover according to an embodiment of the present disclosure.

[0028] [Figure 6] FIG. 2 illustrates an example of a communication method performed in a terminal device according to some embodiments of the present disclosure.

[0029] [Figure 7] FIG. 1 illustrates another example of a communication method performed in a terminal device according to some embodiments of the present disclosure.

[0030] [Figure 8] FIG. 13 illustrates yet another example of a communication method performed in a terminal device according to some embodiments of the present disclosure.

[0031] [Figure 9] FIG. 13 illustrates yet another example of a communication method performed in a terminal device, according to some embodiments of the present disclosure.

[0032] [Figure 10] FIG. 2 illustrates an example of a communication method performed in a network device according to some embodiments of the present disclosure.

[0033] [Figure 11] FIG. 2 illustrates another example of a communication method performed in a network device according to some embodiments of the present disclosure.

[0034] [Figure 12] FIG. 1 illustrates yet another example of a communication method performed in a network device, according to some embodiments of the present disclosure.

[0035] [Figure 13] FIG. 1 illustrates yet another example of a communication method performed in a network device, according to some embodiments of the present disclosure.

[0036] [Figure 14] FIG. 1 is a simplified block diagram of an apparatus suitable for practicing embodiments of the present disclosure.

[0037] In the figures, the same or similar reference numbers represent the same or similar elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] The present disclosure will be described below with reference to some embodiments. These embodiments are merely for illustrative purposes, and are intended to assist those skilled in the art in understanding and implementing the invention, and are not intended to limit the scope of the present disclosure. The present disclosure can be implemented in various ways other than those described below.

[0039] In the following description and claims, unless otherwise defined, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0040] In this specification, the term "terminal device" refers to any device having wireless or wired communication capabilities. Examples of terminal devices include User Equipment (UE), personal computers, desktops, mobile phones, mobile phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, vehicle-mounted devices for V2X communications (where X stands for pedestrians, vehicles, or infrastructure / networks), High Altitude Platforms (HAPs) including Unmanned Aircraft Systems (UASs) and spacecraft or aircraft in Non-terrestrial networks (NTNs) including satellites, and Extended Reality (XR) including different types of reality such as Augmented Reality (AR), Mixed Reality (MR), and Virtual Reality (VR). Examples of such devices include, but are not limited to, mobile reality devices, unmanned aerial vehicles (UAVs), commonly known as drones, which are aircraft that do not require a human pilot, devices on high speed trains (HSTs), imaging devices such as digital cameras, sensors, gaming devices, music storage and playback devices, or Internet devices that enable wireless or wired Internet access and browsing.The "Terminal Equipment" may further have multicast / broadcast capabilities to support public safety, mission critical, V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, wireless software distribution, group communication, and IoT applications. It may also incorporate one or more Subscriber Identity Modules (SIMs), known as multi-SIMs. The term "Terminal Equipment" may be used interchangeably with UE, mobile station, subscriber equipment, mobile terminal, user terminal, or wireless device.

[0041] As used herein, the term "network device" refers to a device capable of providing or hosting a cell or coverage through which terminal devices can communicate. Examples of network devices include, but are not limited to, a Node B (NodeB or NB), an Evolved Node B (eNodeB or eNB), a next generation Node B (gNB), a transmission reception point (TRP), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS), etc.

[0042] A terminal device or a network device may have an artificial intelligence (AI) or machine learning function, which generally includes a model that can be used to learn from a large amount of data collected for a specific function and predict some information.

[0043] The terminal device or network device may function in multiple frequency ranges, e.g., FR1 (410 MHz-7125 MHz), FR2 (24.25 GHz-71 GHz), higher than 100 GHz, Terahertz (THz), etc. Furthermore, it can function in licensed / unlicensed / shared spectrum. The terminal device may have multiple connections with the network device in Multi-Radio Dual Connectivity (MR-DC) application scenarios. The terminal device or network device can function in full duplex, flexible duplex, and cross-division duplex modes.

[0044] Embodiments of the present disclosure may be implemented in test equipment, such as, for example, a signal generator, a signal analyzer, a spectrum analyzer, a network analyzer, a test terminal equipment, a test network equipment, a channel emulator, and the like.

[0045] In one embodiment, the terminal device may be connected to a first network device and a second network device. One of the first network device and the second network device may be a master node, and the other may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs). In one embodiment, the first network device may be a first RAT device, and the second network device may be a second RAT device. In one embodiment, the first RAT device is an eNB, and the second RAT device is a gNB. Information related to the different RATs may be transmitted to the terminal device from at least one of the first network device and the second network device. In one embodiment, the first information may be transmitted to the terminal device from the first network device, and the second information may be transmitted to the terminal device from the second network device directly or via the first network device. In one embodiment, information related to the configuration of the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information relating to the reconfiguration of the terminal device configured by the second network device may be transmitted to the terminal device directly from the second network device or via the first network device.

[0046] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. The term "comprises" and variations thereof are intended to be open ended, meaning "including, but not limited to." The term "based on" is intended to mean "based at least in part on." The terms "one embodiment" and "embodiment" are intended to mean "at least one embodiment." The term "another embodiment" is intended to mean "at least one other embodiment." Terms such as "first," "second," and the like may refer to different objects or the same object. The following content may include other definitions, both explicit and implicit.

[0047] In some instances, values, processes or devices are referred to as "optimum," "lowest," "highest," "minimum," "maximum," etc. It will be understood that such descriptions are intended to indicate choices among multiple functional alternatives that may be used, and that such choices are not necessarily better, smaller, higher, or more preferred than other choices.

[0048] In the context of this disclosure, the term "cell change or addition" may be used interchangeably with "reconfiguration with synchronization of a Secondary Cell Group (SCG) or a Master Cell Group (MCG)". The term "PSCell" refers to an SpCell of an SCG, the term "PCell" refers to an SpCell of an MCG, and the term "SpCell" refers to a primary cell of an SCG or an MCG. The term "SCell" refers to a secondary cell. The term "L1 / L2-based mobility" may be used interchangeably with "L1 / L2-based mobility procedure", "lower layer signaling-based cell change or addition", or "L1 / L2-based handover". The term "lower layer signaling" may be used interchangeably with "L1 / L2 signaling". The term "RRC reconfiguration" may be used interchangeably with "RRC reconfiguration message". The term "data transmission" refers to the transmission and reception of data.

[0049] Currently, it is proposed to specify mechanisms and procedures for L1 / L2 based mobility to reduce mobility delay in the following aspects: - Configuration and maintenance for multiple candidate cells enabling rapid application of configuration for candidate cells -Dynamic switching mechanism between candidate serving cells (including SpCell and SCell) for potential applicable scenarios based on L1 / L2 signaling - L1 extensions for inter-cell beam management, including L1 measurements and reporting, and beam indication -Timing Advance (TA) Management -CU-DU interface signaling to support L1 / L2 mobility if required.

[0050] The L1 / L2 based mobility procedures are applicable to the following scenarios: -Standalone, carrier aggregation (CA), and New Radio (NR) dual connectivity (DC) cases with serving cell change within one cell group (CG) -Intra-DU case and intra-CU inter-DU case (applicable to standalone and CA: no new RAN interfaces expected) - Both intra- and inter-frequency -Both Frequency Range 1 (FR1) and Frequency Range 2 (FR2) The source and target cells may or may not be synchronized.

[0051] SUMMARY OF THE DISCLOSURE Embodiments of the present disclosure provide a solution for improving communications for L1 / L2 based mobility to achieve reduced mobility latency and other potential benefits.

[0052] In one aspect, the RA procedure is performed for a beam associated with a transmission configuration indicator (TCI) state indicated in the L1 / L2 signaling, which can reduce communication delays since the network does not need to send separate L1 / L2 signaling to activate the TCI state.

[0053] In another aspect, the TCI state indicated in the L1 / L2 signaling is used for receiving the physical downlink control channel (PDCCH) after the RA procedure is completed, in this way the network does not need to send another L1 / L2 signaling to activate the TCI state, and communication delays can be reduced accordingly.

[0054] In yet another aspect, a dedicated RA configuration is used for L1 / L2 based mobility, thus improving the performance of the RA procedure for L1 / L2 based mobility.

[0055] In yet another aspect, if the RLF report is triggered by an L1 / L2-based handover, an indication regarding L1 / L2-based mobility is added to the RLF report, in this way the network can recognize the failure due to too early or too late L1 / L2-based handover and further adjust the parameters of the L1 / L2-based handover.

[0056] The principles and implementations of the present disclosure will be described in detail below with reference to the drawings. Communication network example

[0057] 1A is a diagram illustrating an example communication network 100A in which some embodiments of the present disclosure may be implemented. As shown in FIG. 1A, the communication network 100A includes a terminal device 110 and a plurality of network devices 120 and 130 (also simply referred to as network device 120 and network device 130 in this disclosure). The network devices 120 and 130 provide respective cells 121 and 131 that serve the terminal device.

[0058] It should be understood that the number of devices shown in FIG. 1A is for illustration purposes and is not intended to limit the present disclosure. Communications network 100A may include any suitable number of network devices and / or terminal devices adapted to perform implementations of the present disclosure. Network devices 120 and 130 may also each provide more cells for terminal device 110.

[0059] As shown in FIG. 1A, terminal device 110 may communicate with network device 120 or 130 via a channel, such as a wireless communication channel. Communications in communication network 100A may conform to any suitable standard, including, but not limited to, Global System for Mobile Communications (GSM), Long Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), New Radio (NR), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), Machine Type Communication (MTC), and the like. Embodiments of the present disclosure may be performed according to any generation of communication protocols now known or developed in the future. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth generation (6G) networks.

[0060] Communications in the direction from terminal device 110 to network device 120 or 130 are referred to as uplink (UL) communications, and communications in the opposite direction from network device 120 or 130 to terminal device 110 are referred to as downlink (DL) communications. Terminal device 110 may move between cells of network devices 120, 130, and possibly other network devices. In UL communications, terminal device 110 may transmit UL data and control information to network device 120 or 130 over a UL channel. In DL communications, network device 120 or 130 may transmit DL data and control information to terminal device 110 over a DL channel.

[0061] The communication in the communication network 100A may be performed according to the UP and CP protocol stacks. Generally speaking, for a communication device (e.g., a terminal device or a network device), there may be multiple entities of multiple network protocol layers in the protocol stack, and these entities may be configured to perform corresponding processes on data or signaling sent from and received by the communication device. FIG. 1B is a schematic diagram 100B showing network protocol layer entities that may be established for a UP protocol stack in an apparatus according to some embodiments of the present disclosure. In the following, for convenience, the communication between the terminal device 110 and the network device 120 is taken as an example for description. It should be understood that the following description is also suitable for the communication between the terminal device 110 and the network device 130.

[0062] In some embodiments, network devices 120 and 130 may be different network devices. In some embodiments, network devices 120 and 130 may be the same network device.

[0063] As shown in FIG. 1B, in the UP, each of the terminal device 110 and the network device 120 may include an L1 layer entity, i.e., a physical (PHY) layer entity (also referred to as a PHY entity), and one or more entities of upper layers (L2 layer and Layer 3 (L3) layer, or higher layers), including a media access control (MAC) layer entity (also referred to as a MAC entity), a radio link control (RLC) layer entity (also referred to as an RLC entity), a packet data convergence protocol (PDCP) layer entity (also referred to as a PDCP entity), and a service data application protocol (SDAP) layer entity (also referred to as an SDAP entity, which will be established in 5G and subsequent generation networks). In some cases, the PHY, MAC, RLC, PDCP, and SDAP entities are in a stack structure.

[0064] FIG. 1C is a schematic diagram 100C showing network protocol layer entities that may be established for a CP protocol stack in an apparatus according to some embodiments of the present disclosure. As shown in FIG. 1C, in a CP, each of the terminal device 110 and the network device 120 may include an L1 layer entity, i.e., a PHY layer entity (also referred to as a PHY entity), and one or more entities of upper layers (L2 layer and L3 layer), including a MAC layer entity (also referred to as a MAC entity), an RLC layer entity (also referred to as an RLC entity), a PDCP layer entity (also referred to as a PDCP entity), and a radio resource control (RRC) layer entity (also referred to as an RRC entity). The RRC layer may also be referred to as an access stratum (AS) layer, and therefore the RRC entity may further be referred to as an AS entity. As shown in FIG. 1C, the terminal device 110 may further include a non-access stratum (NAS) layer entity (also referred to as a NAS entity). The NAS layer on the network side is located in a core network (CN, not shown), not in a network device. In some cases, these entities are organized into a stack.

[0065] In the context of this disclosure, L1 refers to the PHY layer, L2 refers to the MAC or RLC or PDCP or SDAP layer, and L3 refers to the RRC layer. In the context of this disclosure, L1 or L2 may be collectively referred to as lower layers, and L3 may be referred to as higher layers. Thus, L1 or L2 signaling may be referred to as lower layer signaling, and L3 signaling may be referred to as higher layer signaling.

[0066] Generally, communication channels are divided into logical channels, transmission channels, and physical channels. A physical channel is a channel through which a PHY layer actually transmits information. For example, the physical channel may include a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a physical random-access channel (PRACH), a PDCCH, a physical downlink shared channel (PDSCH), and a physical broadcast channel (PBCH).

[0067] The transmission channel is a channel between the PHY layer and the MAC layer. For example, the transmission channel may include a broadcast channel (BCH), a downlink shared channel (DL-SCH), a paging channel (PCH), an uplink shared channel (UL-SCH), and a random access channel (RACH).

[0068] A logical channel is a channel between the MAC layer and the RLC layer. For example, the logical channel may include a dedicated control channel (DCCH), a common control channel (CCCH), a paging control channel (PCCH), a broadcast control channel (BCCH), and a dedicated traffic channel (DTCH).

[0069] Generally, a channel between the RRC layer and the PDCP layer is referred to as a radio bearer. The terminal device 110 may be configured with at least one data radio bearer (DRB) for carrying data plane data and at least one signaling radio bearer (SRB) for carrying control plane data. In the RRC layer, four types of SRBs may be defined, namely SRB0, SRB1, SRB2, and SRB3. SRB0 uses CCCH for establishing or re-establishing an RRC connection. SRB1 uses DCCH and is established when an RRC connection is established. SRB2 uses DCCH and is established during RRC re-configuration and after initial security activation. SRB3 uses DCCH and is established between the terminal device 110 and the SN when a dual connection is established.

[0070] 1D is a schematic diagram 100D illustrating a CU / DU architecture in which some embodiments of the present disclosure may be implemented. The CU / DU architecture may be established in a network device.

[0071] As shown in FIG. 1D, a CU 141 is shown. It should be understood that more CUs may be included in a UP. The CU 141 may communicate with multiple DUs. Here, two DUs 151 and 152 are shown for illustration. More DUs may be provided for the implementation of the embodiment of the present disclosure. Although not shown, the CU 141 may be responsible for achieving the functions of an SDAP entity and a PDCP entity, and the DUs 151 or 152 may be responsible for achieving the functions of an RLC entity, a MAC entity, and a PHY entity.

[0072] The DU 151 may communicate with transmission / reception points (TRPs) 161, 162, and 163. The DU 152 may communicate with TRPs 164, 165, and 166. Within each TRP, one or more cells may be supported. It should be understood that this is only one example and any more or fewer TRPs are possible. The terminal device 110 may communicate with any of these TRPs.

[0073] In some embodiments, the terminal device 110 may switch from one TRP to another TRP under the control of the same CU and the same DU. For example, the terminal device 110 may be handed over from one cell of TRP161 to another cell of TRP162. This is referred to as an intra-CU intra-DU serving cell change. In some embodiments, the terminal device 110 may switch from one TRP to another TRP under the control of the same CU and a different DU. For example, the terminal device 110 may be handed over from one cell of TRP162 to another cell of TRP164. In this case, a cell change occurs from one cell of DU151 to another cell of DU152. This is referred to as an intra-CU inter-DU serving cell change. In another example, the terminal device 110 may be handed over from a cell of one TRP to a cell of another TRP under the control of a different CU. In this case, a handover occurs from a CU to another CU. This is referred to as an inter-CU handover.

[0074] The network device 120 and the network device 130 may correspond to one or two devices in the same CU. In some embodiments, the network device 120 and the network device 130 may correspond to different TRPs in the same DU. In some embodiments, the network device 120 and the network device 130 may correspond to different TRPs in different DUs.

[0075] 1A , in some embodiments, terminal device 110 may be located within the coverage of cell 121 of network device 120, and terminal device 110 may communicate with network device 120 based on a network configuration. In this case, cell 121 may be referred to as a serving cell of terminal device 110.

[0076] In some embodiments, terminal device 110 may establish a dual connection (i.e., a simultaneous connection) with network device 120 and another network device (not shown). In some embodiments, network device 120 may serve as a master node (MN). In these embodiments, terminal device 110 may communicate with network device 120 via a set of serving cells. The set of serving cells constitutes an MCG, and a primary cell in the MCG is referred to as a PCell. In some scenarios, the PCell may be changed from cell 121 to cell 131. This is referred to as a handover. In some embodiments, network device 120 may function as a secondary node (SN). In these embodiments, the set of serving cells provided by network device 120 forms an SCG, and a primary cell in the SCG is referred to as a PSCell. In some scenarios, the PSCell may be changed from cell 121 to cell 131. This is referred to as a PScell ​​change.

[0077] In some scenarios, the terminal device 110 may receive L1 or L2 signaling indicating the addition, modification, or release of a serving cell from the network device 120. Upon the addition, modification, or release of the serving cell, the terminal device 110 may perform data transmission involving the addition, modification, or change of the serving cell. This procedure is referred to as L1 / L2-based mobility.

[0078] FIG. 1E is a schematic diagram illustrating a process 100E of L1 / L2-based mobility capable of implementing some embodiments of the present disclosure. For illustrative purposes, the process 100E is described with reference to FIG. 1A. The process 100E may involve the terminal device 110 and the network device 120 shown in FIG. 1A. The network device 120 may be an MN or an SN serving the terminal device 110. In this example, the network device 120 provides a serving cell for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0079] 1E, the network device 120 may transmit an RRC reconfiguration including a set of RRC configurations corresponding to a set of candidate cells enabling L1 / L2 based mobility to the terminal device 110 (170). The network device 120 may also transmit beam configurations (e.g., synchronization signal physical broadcast channel block (SSB) or channel state information-reference signal (CSI-RS)) of the candidate cells for L1 measurements to the terminal device 110 (171).

[0080] The terminal device 110 may perform L1 measurements based on the configuration (172). If a condition is met by the beam, e.g., if the quality of the beam is above a threshold quality, the terminal device 110 may report an indication of the beam (e.g., an identity (ID) associated with the beam) to the network device 120 (173).

[0081] The network device 120 may send L1 / L2 signaling (e.g., downlink control information (DCI) or medium access control (MAC) control element (CE)) to the terminal device 110 (174), indicating that the TCI state for a cell among the candidate cells has been activated due to the change or addition of the cell.

[0082] Upon receiving the L1 / L2 signaling, the terminal device 110 may perform a cell change or addition (175). For example, a lower layer (e.g., PHY or MAC layer) of the terminal device 110 indicates cell change or addition information, such as an ID associated with the target cell, to the RRC layer of the terminal device 110. Upon receiving the indication, the RRC layer applies an RRC configuration corresponding to the target cell to perform the cell change or addition. The target cell may be a PCell, a PSCell, or a SCell of the terminal device 110. The terminal device 110 may start data transmission with the target cell using a preconfigured UE dedicated channel and an activated TCI state.

[0083] The embodiments of the present disclosure provide an improved solution for L1 / L2 based mobility procedures, the details of which are described with reference to Figures 2-5. Example of fixed beam implementation in RA procedure

[0084] In a conventional synchronized reconfiguration (handover or PSCell change), if the UE is provided with multiple TCI state configurations via RRC signaling, before the network sends a MAC CE to activate one TCI state in the control resource set (CORESET) after the RA procedure, the UE shall assume that the Demodulation-Reference Signal (DM-RS) antenna port associated with the PDCCH reception is quasi-collocated with the beam (SSB or CSI-RS) identified by the UE during the RA procedure.

[0085] In case of L1 / L2 based mobility, L1 / L2 signaling (e.g. MAC CE) may indicate TCI state and cell change / addition. However, during the RA procedure, the UE may select a beam different from the one associated with the indicated TCI state. Thus, if the UE follows its current behavior and uses the beam selected during the RA procedure, the TCI state activated by the mobility triggering L1 / L2 signaling may not be available after the RA procedure and the network needs to send a MAC CE if it wants to continue using the TCI state.

[0086] In view of this, embodiments of the present disclosure provide a solution for performing an RA procedure using a fixed beam to address these and other potential issues, which is described below with reference to FIG.

[0087] FIG. 2 is a schematic diagram illustrating a process 200 for performing an RA procedure in L1 / L2-based mobility according to an embodiment of the present disclosure. For illustrative purposes, the process 200 is described with reference to FIG. 1A. The process 200 may involve the terminal device 110 and the network device 120 shown in FIG. 1A. The network device 120 may be an MN or an SN serving the terminal device 110. In this example, the network device 120 provides a serving cell for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0088] As shown in FIG. 2, the network device 120 sends (210) lower layer signaling (i.e., L1 / L2 signaling) to the terminal device 110 indicating a cell modification or addition for a cell of the network device 130 (i.e., a target cell). The lower layer signaling may further indicate a TCI status for the cell. In some embodiments, the cell modification or addition may be a PCell modification or addition. In some embodiments, the cell modification or addition may be a PSCell modification or addition. In some embodiments, the cell modification or addition may be a SCell modification or addition.

[0089] For example, the lower layer signaling may indicate a cell change from a serving cell of the network device 120 to a cell of the network device 130. As another example, the lower layer signaling may indicate the addition of a cell of the network device 130. This cell may be a PCell or a PSCell of the terminal device 110. In some embodiments, the lower layer signaling may be carried within a DCI. In some embodiments, the lower layer signaling may be carried within a MAC CE. Of course, any other suitable format is also possible.

[0090] Upon receiving the lower layer signaling, the terminal device 110 determines (220) a Reference Signal (RS) indicated in the lower layer signaling. In some embodiments, the RS may be a synchronization signal and a physical broadcast channel block (SSB). In some embodiments, the RS may be a channel state information reference signal (CSI-RS). It goes without saying that the RS may adopt other suitable formats. The terminal device 110 performs an RA procedure based on the RS. In other words, the terminal device 110 selects an RS during RA resource selection.

[0091] In some embodiments, the terminal device 110 receives L1 / L2-based signaling indicating a cell change or addition and indicating a TCI state (e.g., a TCI state ID) of the target cell, and the terminal device 110 selects an RS associated with the TCI state indicated in the L1 / L2-based signaling during RA resource selection. For example, if an RA procedure is initiated due to L1 / L2-based mobility, the terminal device 110 selects an SSB or CSI-RS associated with the TCI state indicated in the L1 / L2-based signaling (e.g., MAC CE).

[0092] In some embodiments, multiple RSs may be associated with the TCI state. In these embodiments, the terminal device 110 selects an RS (also referred to as a first RS in the present disclosure) having a Quasi-Colocation (QCL) type of Type D from among the multiple RSs, and determines the first RS as an RS associated with the TCI state. In other words, if the TCI state indicated in the lower layer signaling is associated with two RSs, the terminal device 110 may select an RS whose QCL type is Type D. Note that other suitable methods are also possible.

[0093] Upon determining the RS associated with the TCI state, the terminal device 110 performs 230 an RA procedure in the cell based on the RS.

[0094] In some embodiments, process 200 is applied only if a CORESET with an index of zero is set.

[0095] The process 200 performs an RA procedure for L1 / L2 based mobility in a fixed beam associated with a TCI state indicated by L1 / L2 signaling, so the network does not need to send separate L1 / L2 signaling to activate the TCI state, reducing communication delay and overhead. Example of implementation of beam use after RA procedure

[0096] In view of the above problems, an embodiment of the present invention provides another method for beam usage after a RA procedure, which will be described below with reference to FIG.

[0097] 3 is a schematic diagram illustrating another process 300 for performing an RA procedure in L1 / L2-based mobility according to an embodiment of the present disclosure. For illustrative purposes, the process 300 is described with reference to FIG. 1A. The process 300 may involve the terminal device 110 and the network device 120 shown in FIG. 1A. The network device 120 may be an MN or an SN serving the terminal device 110. In this example, the network device 120 provides a serving cell for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0098] As shown in Figure 3, the network device 120 sends (310) lower layer signaling (i.e., L1 / L2 signaling) to the terminal device 110 indicating a cell modification or addition for a cell of the network device 130 (i.e., a target cell). The lower layer signaling further indicates a TCI status for the cell. In some embodiments, the cell modification or addition may be a PCell modification or addition. In some embodiments, the cell modification or addition may be a PSCell modification or addition. In some embodiments, the cell modification or addition may be a SCell modification or addition.

[0099] For example, the lower layer signaling may indicate a cell change from a serving cell of the network device 120 to a cell of the network device 130. As another example, the lower layer signaling may indicate the addition of a cell of the network device 130. This cell may be a PCell or a PSCell of the terminal device 110. In some embodiments, the lower layer signaling may be carried within a DCI. In some embodiments, the lower layer signaling may be carried within a MAC CE. Of course, any other suitable format is also possible.

[0100] Upon receiving the lower layer signaling, the terminal device 110 performs an RA procedure for cell change or addition (320). In other words, the terminal device 110 follows conventional behavior for RS selection in RA resource selection.

[0101] After the RA procedure is completed, the terminal device 110 determines (330) that the DM-RS antenna port for PDCCH reception is quasi-co-located with the RS associated with the TCI state. In other words, the terminal device 110 uses the activated TCI state for PDCCH reception in L1 / L2 signaling after the RA procedure. In some embodiments, the RS may be an SSB. In some embodiments, the RS may be a CSI-RS. It will be appreciated that the RS may adopt other suitable formats.

[0102] For example, after an RA procedure triggered by L1 / L2 signaling based mobility, the UE assumes that the DM-RS antenna port for PDCCH reception is quasi-co-located with the SS / PBCH block or CSI-RS resource of the TCI state indicated in the L1 / L2 signaling (e.g., MAC CE or DCI) that triggers the L1 / L2 signaling based mobility.

[0103] In some embodiments, process 300 is applied only if a CORESET with an index of zero is set.

[0104] In some embodiments, an RRC reconfiguration for a candidate cell does not configure a CORESET with zero index for use in PDCCH reception, and in some embodiments, for a CORESET with a non-zero index, one TCI state is configured for the UE.

[0105] In the process 300, the TCI state indicated in the L1 / L2 signaling is used after the RA procedure is completed, so the network does not need to send another L1 / L2 signaling to activate the TCI state, reducing communication delay and overhead. Example of RA Partition Implementation for L1 / L2 Based Mobility

[0106] Since L1 / L2-based mobility targets low latency, shorter times are expected. For example, the failure detection timer for reconfiguration with synchronization (T304) may be set to a very small value. If traditional RA resources and parameters for RRC-based mobility are reused for L1 / L2-based mobility, the performance of L1 / L2-based mobility may not be guaranteed.

[0107] In view of the above problems, an embodiment of the present invention provides a solution to support RA partition for L1 / L2 based mobility, which is described below with reference to FIG.

[0108] FIG. 4 is a schematic diagram illustrating a process 400 for performing an L1 / L2 based mobility procedure according to an embodiment of the present disclosure. For illustrative purposes, the process 400 is described with reference to FIG. 1A. The process 400 may involve the terminal device 110 and the network device 120 shown in FIG. 1A. The network device 120 may be an MN or an SN serving the terminal device 110. In this example, the network device 120 provides a serving cell for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0109] As shown in FIG. 4, the network device 120 transmits 410 an RA configuration dedicated to the cell change or addition to the terminal device 110 based on lower layer signaling (i.e., L1 / L2 based mobility). In some embodiments, the network device 120 may transmit the RA configuration in system information. For example, the network device 120 transmits the RA configuration in system information block 1 (SIB1). It should be understood that this is merely an example and other suitable methods are possible.

[0110] In some embodiments, the RA configuration may include RA resources and parameters. For example, the RA configuration may include at least one of a preamble configuration, an RA occasion configuration, a PUSCH configuration for 2-step RA, a Reference Signal Receive Power (RSRP) threshold for RS selection, a transport block (TB) size threshold in bits that, when exceeded, causes the UE to use a contention-based RA preamble for group A, or a maximum number of message A transmissions when random access resources for both 4-step and 2-step RA types are configured. It should be understood that these are merely examples and other suitable methods are possible.

[0111] In some embodiments, the network device 120 may configure cell change or addition based on lower layer signaling as a feature associated with the RA partition. That is, the network device 120 may configure L1 / L2 based mobility as one auxiliary feature associated with the RA partition (i.e., an example of a feature combination preamble). For example, the feature combination may be configured as follows: TIFF2025514767000002.tif110168

[0112] Continuing to refer to FIG. 4, the network device 120 transmits (420) lower layer signaling (i.e., L1 / L2 signaling) to the terminal device 110 indicating a cell modification or addition to a cell of the network device 130 (i.e., the target cell). The lower layer signaling further indicates the TCI status of the cell. In some embodiments, the cell modification or addition may be a PCell modification or addition. In some embodiments, the cell modification or addition may be a PSCell modification or addition. In some embodiments, the cell modification may be a SCell modification or addition.

[0113] For example, the lower layer signaling may indicate a cell change from a serving cell of the network device 120 to a cell of the network device 130. In another example, the lower layer signaling may indicate an addition of a cell of the network device 130. This cell may be a PCell or a PSCell of the terminal device 110. In some embodiments, the lower layer signaling may be carried within a DCI. In some embodiments, the lower layer signaling may be carried within a MAC CE. Of course, any other suitable format is also possible.

[0114] Upon receiving the lower layer signaling, the terminal device 110 performs an RA procedure based on the L1 / L2-based mobility-specific RA configuration received from the system information (430).

[0115] The process 400 may improve the performance of the RA procedure for L1 / L2 based mobility. Example implementation of RLF reporting for L1 / L2 based handover

[0116] In general, RLF reports can be used to record information about handover failures and radio link failures. When a failure occurs, the information is stored and reported to the network to help the network identify the cause of the failure and further adjust the handover configuration. The configuration of L1 / L2 based handover is different from other types of handover (e.g., normal handover (HO), conditional handover (CHO), and Dual Active Protocol Stack (DAPS) HO). Therefore, it is necessary to distinguish L1 / L2 based handover from other types of failures.

[0117] In view of the above problems, an embodiment of the present disclosure provides a solution for RLF reporting for L1 / L2 based mobility, which is described below with reference to FIG.

[0118] 5 is a schematic diagram illustrating a process 500 of RLF reporting for L1 / L2-based handover according to an embodiment of the present disclosure. For illustrative purposes, the process 500 is described with reference to FIG. 1A. The process 500 may involve the terminal device 110 and the network device 120 shown in FIG. 1A. The network device 120 may be a MN or SN serving the terminal device 110. In this example, the network device 120 provides a serving cell for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0119] 5, the terminal device 110 determines whether the RLF report was triggered by a lower layer signaling-based handover failure (510). If the RLF report was triggered by a lower layer signaling-based handover failure, the terminal device 110 transmits an RLF report to the network device 120 including an indication that the final handover was a lower layer signaling-based handover (520).

[0120] In some embodiments, if the RLF report is triggered by a radio link failure, terminal device 110 may determine whether the handover before the radio link failure was a lower-layer signaling-based handover. If the handover before the radio link failure was a lower-layer signaling-based handover, terminal device 110 may determine that the RLF report was triggered by a lower-layer signaling-based handover failure. Terminal device 110 may then also send an RLF report to network device 120 that includes an indication that the last handover was a lower-layer signaling-based handover. In this case, the failure may be due to a premature L1 / L2 signaling-based handover.

[0121] Through the process 500, a network receiving the RLF report can recognize that the failure is due to improper L1 / L2 signaling based handover and can further adjust parameters of the L1 / L2 based handover. Example implementation of the method

[0122] Accordingly, embodiments of the present disclosure provide communication methods implemented in a terminal device and a network device, which will now be described with reference to Figures 6 to 13.

[0123] FIG. 6 illustrates an example communication method 600 performed in a terminal device according to some embodiments of the present disclosure. For example, the method 600 can be performed in the terminal device 110 illustrated in FIG. 1A. Hereinafter, the method 600 will be described with reference to FIG. 1A for illustrative purposes. The method 600 may include additional blocks not illustrated and / or some illustrated blocks omitted, but it should be understood that the scope of the present disclosure is not limited thereto. It is assumed that the network device 120 may be a MN or SN serving the terminal device 110. The network device 120 provides a serving cell (e.g., cell 121) for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0124] In block 610, the terminal device 110 receives lower layer signaling from a first network device (e.g., network device 120) indicating a cell change or addition to a cell (e.g., cell 131) of a second network device (e.g., network device 130) and indicating the TCI status of that cell.

[0125] In block 620, the terminal device 110 determines an RS associated with the TCI state. In some embodiments, if a set of RSs is associated with the TCI state, the terminal device 110 determines a first RS in the set of RSs that has a quasi-co-location type of type D as the RS. In some embodiments, the RS may be an SSB. In some embodiments, the RS may be a CSI-RS.

[0126] In block 630, the terminal device 110 performs an RA procedure for cell change or addition based on the RS.

[0127] According to the method 600, an RA procedure for L1 / L2 based mobility is performed in a fixed beam associated with a TCI state indicated by L1 / L2 signaling, so the network does not need to send separate L1 / L2 signaling to activate the TCI state, reducing communication delay and overhead.

[0128] FIG. 7 illustrates another example method 700 of communication performed in a terminal device according to some embodiments of the present disclosure. For example, the method 700 can be performed in the terminal device 110 shown in FIG. 1A. Hereinafter, the method 700 will be described with reference to FIG. 1A for illustrative purposes. The method 700 may include additional blocks not shown and / or some blocks shown may be omitted, but it should be understood that the scope of the present disclosure is not limited in this respect. It is assumed that the network device 120 may be a MN or SN serving the terminal device 110. The network device 120 provides a serving cell (e.g., cell 121) for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0129] In block 710, the terminal device 110 receives lower layer signaling from a first network device (e.g., network device 120) indicating a cell change or addition to a cell (e.g., cell 131) of a second network device (e.g., network device 130) and indicating the TCI status of that cell.

[0130] In block 720, the terminal device 110 performs an RA procedure for a cell change or addition.

[0131] In block 730, the terminal device 110 determines that the DM-RS antenna port for PDCCH reception is quasi-co-located with the RS associated with the TCI state after the RA procedure is completed. In some embodiments, the RS may be an SSB. In some embodiments, the RS may be a CSI-RS.

[0132] In the method 700, the TCI state indicated in the L1 / L2 signaling is used after the RA procedure is completed, so the network does not need to send another L1 / L2 signaling to activate the TCI state, reducing communication delays and overhead.

[0133] FIG. 8 illustrates another example method 800 of communication performed in a terminal device according to some embodiments of the present disclosure. For example, the method 800 can be performed in the terminal device 110 shown in FIG. 1A. Hereinafter, the method 800 will be described with reference to FIG. 1A for illustrative purposes. The method 800 may include additional blocks not shown and / or some blocks shown may be omitted, but it should be understood that the scope of the present disclosure is not limited in this respect. It is assumed that the network device 120 may be a MN or SN serving the terminal device 110. The network device 120 provides a serving cell (e.g., cell 121) for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0134] In block 810, the terminal device 110 receives an RA configuration dedicated to the change or addition of a cell based on lower layer signaling from a first network device (e.g., the network device 120). In some embodiments, the change or addition of a cell based on lower layer signaling may be configured as a function associated with a random access partition.

[0135] At block 820, terminal device 110 determines whether it has received lower layer signaling from network device 120. The lower layer signaling may indicate a cell change or addition to a cell (e.g., cell 131) of a second network device (e.g., network device 130). If lower layer signaling is received, method 800 proceeds to block 830.

[0136] In block 830, the terminal device 110 performs a cell change or addition based on the RA configuration.

[0137] The method 800 may improve performance of RA procedures for L1 / L2 based mobility.

[0138] FIG. 9 illustrates yet another example method 900 of communication performed in a terminal device, according to some embodiments of the present disclosure. For example, the method 900 can be performed in the terminal device 110 shown in FIG. 1A. Hereinafter, the method 900 will be described with reference to FIG. 1A for illustrative purposes. The method 900 may include additional blocks not shown and / or some blocks shown may be omitted, but it should be understood that the scope of the present disclosure is not limited in this respect. It is assumed that the network device 120 may be a MN or SN serving the terminal device 110. The network device 120 provides a serving cell (e.g., cell 121) for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0139] In block 910, terminal device 110 determines whether the RLF reporting was triggered due to a lower layer signaling based handover failure. If the RLF reporting was triggered due to a lower layer signaling based handover failure, method 900 proceeds to block 920.

[0140] In block 920, terminal device 110 sends an RLF report to network device 120 that includes an indication that the final handover was a lower layer signaling-based handover.

[0141] In some embodiments, if the RLF report is triggered by a radio link failure, terminal device 110 may determine whether the handover before the radio link failure was a lower layer signaling-based handover. If the handover before the radio link failure was a lower layer signaling-based handover, terminal device 110 may determine that the radio link failure report was triggered by a failure of the lower layer signaling-based handover.

[0142] Method 900 may allow failures due to premature or late L1 / L2 signaling based handover to be reported to the network.

[0143] FIG. 10 illustrates an example communication method 1000 performed in a network device according to some embodiments of the present disclosure. For example, the method 1000 can be performed by the network device 120 or 130 illustrated in FIG. 1A. Hereinafter, the method 1000 will be described with reference to FIG. 1A for illustrative purposes. The method 1000 may include additional blocks not illustrated and / or omit some illustrated blocks, but it should be understood that the scope of the present disclosure is not limited in this respect. It is assumed that the network device 120 may be a MN or SN serving the terminal device 110. The network device 120 provides a serving cell (e.g., cell 121) for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0144] As shown in FIG. 10, in block 1010, a first network device (e.g., network device 120) transmits lower layer signaling to terminal device 110 indicating a cell change or addition to a cell of a second network device (e.g., network device 130) and indicating the TCI status of the cell.

[0145] At block 1020, the network device 120 determines an RS associated with the TCI state. In some embodiments, if a set of RSs is associated with the TCI state, the network device 120 determines a first RS in the set of RSs that has a quasi-co-location type of type D as the RS. In some embodiments, the RS may be an SSB. In some embodiments, the RS may be a CSI-RS.

[0146] At block 1030, the network device 120 performs an RA procedure for changing or adding a cell based on the RS.

[0147] According to the method 1000, an RA procedure for L1 / L2 based mobility is performed in a fixed beam associated with a TCI state indicated by L1 / L2 signaling, so the network does not need to send separate L1 / L2 signaling to activate the TCI state, reducing communication delay and overhead.

[0148] FIG. 11 illustrates another example method 1100 of communication performed in a network device according to some embodiments of the present disclosure. For example, the method 1100 can be performed by the network device 120 or 130 illustrated in FIG. 1A. Hereinafter, the method 1100 will be described with reference to FIG. 1A for the purpose of explanation. It should be understood that the method 1100 may include additional blocks not illustrated and / or omit some illustrated blocks, and the scope of the present disclosure is not limited in this respect. It is assumed that the network device 120 may be a MN or SN serving the terminal device 110. The network device 120 provides a serving cell (e.g., cell 121) for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0149] As shown in FIG. 11, in block 1110, a first network device (e.g., network device 120) transmits lower layer signaling to terminal device 110 indicating a cell change or addition to a cell of a second network device (e.g., network device 130) and indicating the TCI status of the cell.

[0150] At block 1120, the network device 120 performs an RA procedure for the cell change or addition.

[0151] In block 1130, the network device 120 determines that the DM-RS antenna port for PDCCH transmission is quasi-co-located with the RS associated with the TCI state after the RA procedure is completed. In some embodiments, the RS may be an SSB. In some embodiments, the RS may be a CSI-RS.

[0152] According to the method 1100, the TCI state indicated in the L1 / L2 signaling is used after the RA procedure is completed, so the network does not need to send another L1 / L2 signaling to activate the TCI state, reducing communication delay and overhead.

[0153] FIG. 12 illustrates yet another example method 1200 of communication performed in a network device according to some embodiments of the present disclosure. For example, the method 1200 can be performed by the network device 120 or 130 illustrated in FIG. 1A. Hereinafter, the method 1200 will be described with reference to FIG. 1A for the purpose of explanation. It should be understood that the method 1200 may include additional blocks not illustrated and / or omit some illustrated blocks, and the scope of the present disclosure is not limited in this respect. It is assumed that the network device 120 may be a MN or SN serving the terminal device 110. The network device 120 provides a serving cell (e.g., cell 121) for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0154] 12, in block 1210, a first network device (e.g., network device 120) generates an RA configuration dedicated to the change or addition of a cell based on lower layer signaling. In some embodiments, the change or addition of a cell based on lower layer signaling may be configured as a function associated with a random access partition.

[0155] In block 1220 , the network device 120 transmits the RA configuration to the terminal device 110 .

[0156] The method 1200 may allow a dedicated RA configuration to be configured to improve the performance of RA procedures for L1 / L2 based mobility.

[0157] FIG. 13 illustrates yet another example method 1300 of communication performed in a network device, according to some embodiments of the present disclosure. For example, the method 1300 can be performed by the network device 120 or 130 illustrated in FIG. 1A. Hereinafter, the method 1300 will be described with reference to FIG. 1A for the purpose of explanation. It should be understood that the method 1300 may include additional blocks not illustrated and / or omit some illustrated blocks, and the scope of the present disclosure is not limited in this respect. It is assumed that the network device 120 may be a MN or SN serving the terminal device 110. The network device 120 provides a serving cell (e.g., cell 121) for the terminal device 110. The network device 130 does not provide a serving cell for the terminal device 110.

[0158] As shown in FIG. 13, in block 1310, a first network device (eg, network device 120) receives an RLF report from terminal device 110 that includes an indication that the final handover is a handover based on lower layer signaling.

[0159] At block 1320, the network device 120 adjusts parameters of the handover based on the lower layer signaling.

[0160] The method 1300 allows the network to recognize failures due to too early or too late L1 / L2 signaling based handover and further adjust parameters of the L1 / L2 signaling based handover.

[0161] It should be noted that the operations of the methods 600-1300 are similar to those described with reference to FIGS. 2-5, and other details will not be repeated here for the sake of brevity. Device and equipment implementation examples

[0162] 14 is a simplified block diagram of an apparatus 1400 suitable for carrying out embodiments of the present disclosure. The apparatus 1400 may be considered as a further example of the terminal apparatus 110, the network apparatus 120, or the network apparatus 130 shown in FIG. 1A. Thus, the apparatus 1400 may be implemented in, or as at least a part of, the terminal apparatus 110, the network apparatus 120, or the network apparatus 130.

[0163] As shown, the apparatus 1400 comprises a processor 1410, a memory 1420 coupled to the processor 1410, a suitable transmitter (TX) and receiver (RX) 1440 coupled to the processor 1410, and a communication interface coupled to the TX / RX 1440. The memory 1410 stores at least a portion of a program 1430. The TX / RX 1440 is used for bidirectional communication. The TX / RX 1440 has at least one antenna to facilitate communication, although the access nodes referred to herein may in practice have multiple antennas. The communication interface may represent any interface required for communication with other network elements, such as the X2 interface for bidirectional communication between eNB / gNB, the S1 / NG interface for communication between a Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and a gNB / eNB, the Un interface for communication between a gNB / eNB and a relay node (RN), and the Uu interface for communication between a gNB / eNB and a terminal device.

[0164] The program 1430 is assumed to include program instructions that, when executed by the associated processor 1410, enable the device 1400 to operate according to embodiments of the present disclosure, as described herein with reference to Figures 1A-13. The embodiments of the present disclosure may be implemented by computer software executable by the processor 1410 of the device 1400, or by hardware, or by a combination of software and hardware. The processor 1410 may be configured to implement various embodiments of the present disclosure. Furthermore, the combination of the processor 1410 and the memory 1420 may form a processing means 1450 suitable for implementing various embodiments of the present disclosure.

[0165] The memory 1420 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, such as, by way of non-limiting example, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. Although only one memory 1420 is shown in the device 1400, there may be several physically different memory modules in the device 1400. The processor 1410 may be of any type suitable for a local technology network and may include, by way of non-limiting example, one or more of a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP) and a processor based on a multi-core processor architecture. The device 1400 may have multiple processors, for example application specific integrated circuit chips time-slaved to a clock that synchronizes the main processor.

[0166] In some embodiments, a terminal device comprises circuitry configured to receive lower layer signaling from a first network device indicating a cell change or addition to a cell of a second network device and indicating a transmission configuration indicator state of the cell, determine a reference signal associated with the transmission configuration indicator state, and perform a random access procedure for the cell change or addition based on the reference signal.

[0167] In some embodiments, the circuitry may be configured to determine the reference signal according to a determination that the set of reference signals is associated with a transmission configuration indicator state by determining as the reference signal a first reference signal in the set of reference signals having a quasi-colocation of type D.

[0168] In some embodiments, a terminal device comprises circuitry configured to receive, from a first network device, lower layer signaling indicating a change or addition of a cell to a cell of a second network device and indicating a transmission configuration indicator state of the cell, perform a random access procedure for the change or addition of the cell, and determine, after the random access procedure is completed, that a demodulation reference signal antenna port for receiving a physical downlink control channel is quasi-co-located with a reference signal associated with the transmission configuration indicator state. In some embodiments, the reference signal is an SSB or a CSI-RS.

[0169] In some embodiments, the terminal device includes circuitry configured to receive from the network device a random access configuration dedicated to changing or adding a cell based on lower layer signaling, and to change or add a cell based on the random access configuration in response to receiving the lower layer signaling.

[0170] In some embodiments, the modification or addition of cells based on lower layer signaling is configured as a function associated with a random access partition.

[0171] In some embodiments, the terminal device includes circuitry configured to determine whether the radio link failure report was triggered due to a failure of a handover based on lower layer signaling, and, in accordance with a determination that the radio link failure report was triggered due to a failure of a handover based on lower layer signaling, send a radio link failure report to a network device, the radio link failure report including an indication that the last handover was a handover based on lower layer signaling.

[0172] In some embodiments, the circuitry may be configured to determine whether the radio link failure report was triggered due to a failure of a lower layer signaling based handover by: determining whether the handover before the radio link failure was a lower layer signaling based handover in accordance with a determination that the radio link failure report was triggered due to a radio link failure; and determining that the radio link failure report was triggered due to a failure of a lower layer signaling based handover in accordance with a determination that the handover before the radio link failure was a lower layer signaling based handover.

[0173] In some embodiments, the first network device comprises circuitry configured to: transmit lower layer signaling to a terminal device indicating a cell change or addition to a cell of a second network device and indicating a transmission configuration indicator state of the cell; determine a reference signal associated with the transmission configuration indicator state; and perform a random access procedure for the cell change or addition based on the reference signal.

[0174] In some embodiments, the circuitry may be configured to determine the reference signal according to a determination that the set of reference signals is associated with a transmission configuration indicator state by determining as the reference signal a first reference signal in the set of reference signals having a quasi-colocation of type D.

[0175] In some embodiments, the first network device comprises circuitry configured to: transmit lower layer signaling to a terminal device indicating a cell change or addition to a cell of a second network device and indicating a transmission configuration indicator state of the cell; perform a random access procedure for the cell change or addition; and determine, after the random access procedure is completed, that a demodulation reference signal antenna port for a physical downlink control channel transmission is quasi-co-located with a reference signal associated with the transmission configuration indicator state.

[0176] In some embodiments, the reference signal is an SSB or a CSI-RS.

[0177] In some embodiments, the first network device includes circuitry configured to generate a random access configuration dedicated to changing or adding a cell based on lower layer signaling and to transmit the random access configuration to a terminal device.

[0178] In some embodiments, the modification or addition of cells based on lower layer signaling is configured as a function associated with a random access partition.

[0179] In some embodiments, the network device comprises circuitry configured to receive a radio link failure report from the terminal device including an indication that the last handover was a handover based on lower layer signaling, and to adjust parameters of the handover based on lower layer signaling.

[0180] The term "circuitry" as used herein may refer to hardware circuits and / or a combination of hardware circuits and software. For example, a circuit may be a combination of analog and / or digital hardware circuits and software / firmware. As a further example, a circuit may be any portion of a hardware processor with software, such as a digital signal processor, software, and memory that work together to perform various functions on a device, such as a terminal device or a network device. In yet another example, a circuit may be a hardware circuit and / or processor, such as a microprocessor or a portion of a microprocessor, that requires software / firmware for operation, but the software may not be present when not required for operation. As used herein, the term circuitry also encompasses merely a hardware circuit or processor, or a portion of a hardware circuit or processor, and its (or their) accompanying software and / or firmware implementations.

[0181] Overall, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure have been illustrated and described using block diagrams, flow charts, or some other pictorial representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented, by way of non-limiting examples, in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or any combination thereof.

[0182] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in a program module, that execute in a device on a target real or virtual processor to perform a process or method as described above with reference to Figures 1A-13. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split between program modules as appropriate. The machine-executable instructions of the program modules may be executed in local or distributed devices. In a distributed device, the program modules may be located in both local and remote storage media.

[0183] The program codes for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, a special purpose computer, or other programmable data processing equipment, and when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may run entirely on the machine, partially on the machine, as a separate software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0184] The above program code may be embodied on a machine-readable medium, which may be any tangible medium that contains or stores a program used by or in conjunction with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable-programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0185] It should be understood that although operations have been described in a particular order, it is not required that such operations be performed in the particular order or sequence shown, or that all of the operations shown be performed, in order to achieve desired results. In some situations, multitasking and parallel processing may be advantageous. Similarly, although the above discussion includes details of some specific embodiments, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to certain embodiments. Some features that are described in the context of individual embodiments may be implemented in combination in an embodiment. Conversely, various features that are described in the context of an embodiment may be implemented in multiple embodiments separately or in any suitable subcombination.

[0186] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the present disclosure, as defined by the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. receiving, at the terminal device, lower layer signaling from a first network device indicating a change or addition of a cell to a cell of a second network device and indicating a transmission configuration indicator state of the cell; determining a reference signal associated with the transmission configuration indicator state; and performing a random access procedure for changing or adding the cell based on the reference signal.

2. Determining the reference signal comprises:

2. The method of claim 1, comprising: determining, in accordance with a determination that a set of reference signals is associated with the transmission configuration indicator state, a first reference signal in the set of reference signals having a quasi-colocation of type D as the reference signal.

3. receiving, at the terminal device, lower layer signaling from a first network device indicating a change or addition of a cell to a cell of a second network device and indicating a transmission configuration indicator state of the cell; performing a random access procedure for changing or adding the cell; determining, after the random access procedure is completed, that a demodulation reference signal antenna port for receiving a physical downlink control channel is quasi-collocated with a reference signal associated with the transmission configuration indicator state.

4. The method according to any one of claims 1 to 3, wherein the reference signal is a synchronization signal and a physical broadcast channel block (SSB), or a channel state information reference signal (CSI-RS).

5. In the terminal device, receiving from a network device a random access configuration dedicated to changing or adding a cell based on lower layer signaling; and changing or adding the cell based on the random access configuration in response to receiving the lower layer signaling.

6. The method of claim 5 , wherein the change or addition of a cell based on the lower layer signaling is configured as a function associated with a random access partition.

7. determining, in the terminal device, whether a radio link failure report is triggered by a handover failure based on lower layer signaling; and transmitting, in accordance with a determination that the radio link failure report was triggered due to a failure of the lower layer signaling based handover, a radio link failure report to a network device, the radio link failure report including an indication that a final handover is a lower layer signaling based handover.

8. Determining whether the radio link failure report is triggered by a failure of the lower layer signaling based handover comprises: determining whether a handover before the radio link failure is a lower layer signaling based handover according to determining that the radio link failure report is triggered by a radio link failure; and determining, in accordance with a determination that the handover prior to the radio link failure was the lower layer signaling based handover, that the radio link failure report was triggered by a failure of the lower layer signaling based handover.

9. transmitting, in a first network device, lower layer signaling to a terminal device, indicating a change or addition of a cell to a cell of a second network device and indicating a transmission configuration indicator state of the cell; determining a reference signal associated with the transmission configuration indicator state; and performing a random access procedure for changing or adding the cell based on the reference signal.

10. Determining the reference signal comprises:

10. The method of claim 9, comprising: determining, in accordance with a determination that a set of reference signals is associated with the transmission configuration indicator state, a first reference signal in the set of reference signals having a quasi-colocation of type D as the reference signal.

11. transmitting, in a first network device, lower layer signaling to a terminal device, indicating a change or addition of a cell to a cell of a second network device and indicating a transmission configuration indicator state of the cell; performing a random access procedure for changing or adding the cell; determining, after the random access procedure is completed, that a demodulation reference signal antenna port for a physical downlink control channel transmission is quasi-collocated with a reference signal associated with the transmission configuration indicator state.

12. The method according to any one of claims 9 to 11, wherein the reference signal is a synchronization signal and a physical broadcast channel block (SSB), or a channel state information reference signal (CSI-RS).

13. In a first network device, generating a random access configuration dedicated to changing or adding a cell based on lower layer signaling; and transmitting the random access configuration to a terminal device.

14. The method of claim 13 , wherein the change or addition of a cell based on the lower layer signaling is configured as a function associated with a random access partition.

15. receiving, at the network device, a radio link failure report from the terminal device, the radio link failure report including an indication that the final handover was a lower layer signaling based handover; and adjusting a parameter of the handover based on the lower layer signaling.

16. A terminal device, A terminal device comprising a processor configured to cause the terminal device to perform a method according to any one of claims 1-2, any one of claims 3-4, any one of claims 5-6 or any one of claims 7-8.

17. A network device, A network device comprising a processor configured to cause said network device to perform a method according to any one of claims 9 to 10, any one of claims 11 to 12, any one of claims 13 to 14 or 15.

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