User equipment initiated cell handover

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The invention relates to an apparatus and method for UE initiated cell handover. A method for operating a user equipment (UE) includes receiving configuration information of a reference signal associated with measurements of one or more candidate cells, receiving configuration information of a transmission configuration indicator (TCI) state list associated with the one or more candidate cells, performing measurements on the reference signal, determining a measurement report based on the measurements, and transmitting the measurement report to the UE. And sending the measurement report.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communication systems, and more particularly, to user equipment (UE) initiated cell handover. Background Art

[0002] The demand for wireless data traffic is increasing rapidly due to the growing popularity of smartphones and other mobile data devices (such as tablets, "notepad" computers, netbooks, e-book readers and machine-type devices) among consumers and enterprises. To meet the high growth in mobile data traffic and support new applications and deployments, improvements in radio interface efficiency and coverage are critical.

[0003] Fifth generation (5G) or New Radio (NR) mobile communications are gathering increasing momentum recently, with all global technical activities from industry and academia on various candidate technologies. Candidate enablers for 5G / NR mobile communications include massive antenna technology from traditional cellular bands up to high frequencies to provide beamforming gain and support increased capacity, new waveforms (e.g., new radio access technologies (RATs)) that flexibly accommodate various services / applications with different requirements, new multiple access schemes that support massive connectivity, etc.

[0004] 5G mobile communication technology defines a wide frequency band so that high transmission rates and new services are possible, and can be realized not only in "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands called millimeter waves including 28 GHz and 39 GHz. In addition, it has been considered to implement 6G mobile communication technology (called super 5G system) in terahertz frequency bands (for example, 95 GHz to 3 THz frequency bands) in order to achieve a transmission rate fifty times faster than 5G mobile communication technology and an ultra-low latency one-tenth of 5G mobile communication technology.

[0005] At the beginning of the development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine type communication (mMTC), there has been ongoing standardization on beamforming and massive MIMO for mitigating radio wave path loss in mmWave and increasing radio wave transmission distance, dynamic operation of parameter sets (e.g., operating multiple subcarrier spacings) and slot formats to support efficient use of mmWave resources, initial access technology for supporting multi-beam transmission and broadband, definition and operation of BWP (bandwidth part), new channel coding methods such as LDPC (low-density parity check) codes for large-volume data transmission and polar codes for highly reliable transmission of control information, L2 preprocessing, and network slicing for providing dedicated networks tailored for specific services.

[0006] Currently, there are ongoing discussions on the improvement and performance enhancement of initial 5G mobile communication technologies in view of the services to be supported by 5G mobile communication technologies, and there has been physical layer standardization on technologies such as: V2X (Vehicle-to-Everything) for assisting driving decisions of autonomous vehicles based on information on the position and status of vehicles transmitted by vehicles and for enhancing user convenience, NR-U (Unlicensed New Radio) for system operation that is intended to comply with various regulatory-related requirements within unlicensed frequency bands, NR UE energy saving, non-terrestrial networks (NTN) as UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is not possible, and positioning.

[0007] In addition, in the air interface architecture / protocol, there is already ongoing standardization of technologies such as the Industrial Internet of Things (IIoT) that supports new services through interconnection and convergence with other industries, IAB (Integrated Access and Backhaul) that provides nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access (two-step RACH for NR) for simplifying the random access procedure. In terms of system architecture / services, standardization is also ongoing on the 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0008] As 5G mobile communication systems are commercialized, the number of connected devices, which has been growing exponentially, will be connected to the communication network, and it is expected that enhanced functions and performance of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled on extended reality (XR) for effectively supporting AR (augmented reality), VR (virtual reality), MR (mixed reality), etc., 5G performance improvement and complexity reduction by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

[0009] Furthermore, such development of 5G mobile communication systems will serve as the basis for developing not only new waveforms for providing terahertz band coverage for 6G mobile communication technology, multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas, metamaterial-based lenses and antennas for improving terahertz band signal coverage, high-dimensional spatial multiplexing technology using OAM (orbital angular momentum), and RIS (reconfigurable smart surfaces), but also full-duplex technology for improving the frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technology for achieving system optimization by utilizing satellites and AI (artificial intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for realizing services at a complexity level that exceeds the limits of UE operating capabilities by utilizing ultra-high-performance communication and computing resources.

[0010] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with respect to the present disclosure. Summary of the invention

[0011] Technical issues

[0012] The present disclosure relates to an apparatus and method for UE-initiated cell switching.

[0013] Solution to the problem

[0014] In one embodiment, a user equipment (UE) is provided. The UE includes a transceiver configured to receive configuration information of a reference signal associated with measurement of one or more candidate cells, and receive configuration information of a transmission configuration indicator (TCI) state list associated with one or more candidate cells. The UE also includes a processor operably coupled to the transceiver, the processor configured to perform measurements on the reference signal and determine a measurement report based on the measurements. The transceiver is also configured to send a measurement report. The measurement report includes L×M measurements. L is the number of cells included in the measurement report, and M is the number of measurements reported for each of the multiple cells in the measurement report. The measurement report includes a reference signal ID and a corresponding measured L1-reference signal received power (L1-RSRP). The measurement report is included in uplink control information (UCI) and sent on a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH).

[0015] In another embodiment, a base station (BS) is provided. The BS includes a transceiver configured to send configuration information of a reference signal associated with measurement of one or more candidate cells, send configuration information of a TCI state list associated with one or more candidate cells, and receive a measurement report. The measurement report includes L×M measurements. L is the number of cells included in the measurement report, and M is the number of measurements reported for each of the multiple cells in the measurement report. The measurement report includes a reference signal ID and a corresponding measured L1-RSRP. The measurement report is included in the UCI and is received on the PUCCH or PUSCH.

[0016] In yet another embodiment, a method of operating a UE is provided. The method includes receiving configuration information of a reference signal associated with measurement of one or more candidate cells, receiving configuration information of a TCI state list associated with one or more candidate cells, performing measurements on the reference signal, determining a measurement report based on the measurements, and sending a measurement report. The measurement report includes L×M measurements. L is the number of cells included in the measurement report, and M is the number of measurements reported for each of the multiple cells in the measurement report. The measurement report includes a reference signal ID and a corresponding measured L1-RSRP. The measurement report is included in the UCI and sent on the PUCCH or PUSCH.

[0017] Other technical features may be apparent to those skilled in the art from the following drawings, descriptions and claims.

[0018] Before the following detailed description, it may be advantageous to set forth the definitions of certain words and phrases used throughout this patent document. The term "coupling" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not these elements are in physical contact with each other. The terms "send", "receive" and "communication" and their derivatives cover both direct and indirect communication. The terms "include" and "comprise" and their derivatives mean including but not limited to. The term "or" is inclusive, meaning and / or. The phrase "associated with ... " and its derivatives mean including, included in ..., interconnected with ..., including, included in ..., connected to or with ..., coupled to or with ..., can communicate with ..., collaborate with ..., interlace, juxtapose, approach, bind to or with ..., have, have the nature of ..., have to or with ..., etc. The term "controller" means any device, system or part thereof that controls at least one operation. Such a controller can be implemented in hardware or a combination of hardware and software and / or firmware. The function associated with any particular controller can be centralized or distributed, whether local or remote. The phrase "at least one of" when used with a list of items means that different combinations of one or more of the listed items can be used, and that only one of the items in the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0019] In addition, the various functions described below may be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data, or a portion thereof, suitable for implementation in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disk (DVD), or any other type of memory. "Non-transitory" computer-readable media excludes wired, wireless, optical, or other communication links that transmit temporary electrical or other signals. Non-transitory computer-readable media include media in which data can be permanently stored and media in which data can be stored and later rewritten, such as rewritable optical disks or erasable memory devices.

[0020] Definitions for certain other words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

[0021] Advantageous Effects of the Invention

[0022] The present disclosure may provide an apparatus and method for UE-initiated cell switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0024] FIG1 illustrates an example wireless network according to an embodiment of the present disclosure;

[0025] FIG. 2A illustrates an example wireless transmission path according to an embodiment of the present disclosure.

[0026] FIG. 2B illustrates an example wireless receive path according to an embodiment of the present disclosure.

[0027] FIG3A illustrates an example gNodeB (gNB) according to an embodiment of the present disclosure;

[0028] FIG3B shows an example UE according to an embodiment of the present disclosure;

[0029] FIG4A illustrates an example beam in a wireless system according to the present disclosure;

[0030] FIG4B shows an example of multi-beam in a wireless system according to the present disclosure;

[0031] FIG5 illustrates an example antenna block or array according to an embodiment of the present disclosure;

[0032] FIG6 shows an example of beam changing from a TRP of a serving cell to a TRP of a cell having a PCI different from the PCI of the serving cell according to the present disclosure;

[0033] FIG. 7 shows an example of a UE configuration according to the present disclosure;

[0034] FIG8 illustrates an example method of switching based on TCI status indication according to the present disclosure;

[0035] FIG. 9 illustrates an example method of switching to a target (or candidate) cell after a beam application delay according to the present disclosure;

[0036] FIG10 illustrates an example method of switching based on TCI status indication according to the present disclosure;

[0037] FIG11 illustrates an example method of switching to a target (or candidate) cell after a cell switching application delay according to the present disclosure;

[0038] FIG12 illustrates an example method based on UE-initiated handover according to the present disclosure;

[0039] FIG. 13 illustrates an example method of switching to a target (or candidate) cell after a cell switching time according to the present disclosure;

[0040] FIG14 illustrates an example method based on UE-initiated handover according to the present disclosure;

[0041] Figure 15 shows an example method based on UE-initiated handover. According to the present disclosure;

[0042] FIG16 illustrates an example method based on UE-initiated handover according to the present disclosure;

[0043] FIG. 17 illustrates an example method for switching to a target (or candidate) cell after a cell switching time according to the present disclosure; and

[0044] FIG. 18 shows an example method of UE-initiated cell switching according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0045] FIG. 1 through FIG. 18 discussed below and the various embodiments used to describe the principles of the present disclosure in this patent document are illustrative only and should not be construed in any way to limit the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure can be implemented in any suitably arranged wireless communication system.

[0046] The following documents and standard descriptions are hereby incorporated into the present disclosure as if fully set forth herein: 3GPP TS 38.211 v17.2.0, “NR; Physical channels and modulation”; 3GPP TS 38.212 v17.2.0, “NR; Multiplexing and Channel coding”; 3GPP TS 38.213 v17.2.0, “NR; Physical Layer Procedures for Control”; 3GPP TS 38.214 v17.1.0, “NR; Physical Layer Procedures for Data”; 3GPP TS 38.321 v17.1.0, “NR; Medium Access Control (MAC) protocol specification”; 3GPP TS 38.331 v17.1.0, “NR; Radio Resource Control (RRC) Protocol Specification”, and 3GPP RP-213565, “Further NR Mobility Enhancements”.

[0047] In order to meet the demand for wireless data services that has increased since the deployment of 4G communication systems and to realize various vertical applications, 5G / NR communication systems have been developed and are currently being deployed. 5G / NR communication systems are considered to be implemented in higher frequency (millimeter wave) bands (e.g., 28 GHz or 60 GHz bands) to achieve higher data rates, or in lower frequency bands (such as 6 GHz) to achieve robust coverage and mobility support. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed in 5G / NR communication systems.

[0048] In addition, in the 5G / NR communication system, system network improvements are being developed based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communications, coordinated multi-point (CoMP), receiving-end interference cancellation, etc.

[0049] The discussion of 5G systems and frequency bands associated therewith is for reference, as certain embodiments of the present disclosure may be implemented in 5G systems. However, the present disclosure is not limited to 5G systems or frequency bands associated therewith, and embodiments of the present disclosure may be used in conjunction with any frequency band. For example, aspects of the present disclosure may also be applied to the deployment of 5G communication systems, 6G, or even later versions that may use terahertz (THz) frequency bands.

[0050] The following Figures 1-3 describe various embodiments implemented in a wireless communication system and using orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication technology. The description of Figures 1-3 is not meant to imply physical or architectural limitations on the manner in which different embodiments may be implemented. Different embodiments of the present disclosure may be implemented in any appropriately arranged communication system.

[0051] FIG1 illustrates an example wireless network according to an embodiment of the present disclosure. The embodiment of the wireless network shown in FIG1 is for illustration only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present disclosure.

[0052] As shown in Figure 1, the wireless network includes gNB 101 (e.g., base station, BS), gNB 102, and gNB 103. gNB 101 communicates with gNB 102 and gNB 103. gNB 101 also communicates with at least one network 130 such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0053] gNB 102 provides wireless broadband access to network 130 for a first plurality of user equipment (UE) within coverage area 120 of gNB 102. The first plurality of UEs includes UE 111, which may be located in a small business; UE 112, which may be located in an enterprise; UE 113, which may be a WiFi hotspot; UE 114, which may be located in a first residence; UE 115, which may be located in a second residence; and UE 116, which may be a mobile device such as a cellular phone, a wireless laptop, a wireless PDA, etc. gNB 103 provides wireless broadband access to network 130 for a second plurality of UEs within coverage area 125 of gNB 103. The second plurality of UEs includes UE 115 and UE 116. In some embodiments, one or more of gNBs 101-103 may communicate with each other and with UEs 111-116 using 5G / NR, Long Term Evolution (LTE), Long Term Evolution-Advanced (LTE-A), WiMAX, WiFi, or other wireless communication technologies.

[0054] Depending on the network type, the term "base station" or "BS" may refer to any component (or collection of components) configured to provide wireless access to a network, such as a transmission point (TP), a transmission-reception point (TRP), an enhanced base station (eNodeB or eNB), a 5G / NR base station (gNB), a macro cell, a femto cell, a WiFi access point (AP), or other wireless enabling devices. The base station may provide wireless access according to one or more wireless communication protocols (e.g., 5G / NR Third Generation Partnership Project (3GPP) NR, Long Term Evolution (LTE), LTE Advanced (LTE-A), High Speed ​​Packet Access (HSPA), Wi-Fi 802.11 a / b / g / n / ac, etc.). For convenience, the terms "BS" and "TRP" are used interchangeably in this patent document to refer to a network infrastructure component that provides wireless access to a remote terminal. In addition, depending on the network type, the term "user equipment" or "UE" may refer to any component, such as a "mobile station", "subscriber station", "remote terminal", "wireless terminal", "reception point", or "user equipment". For convenience, the terms "user equipment" and "UE" are used in this patent document to refer to a remote wireless device that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile phone or smartphone) or is generally considered a fixed device (such as a desktop computer or vending machine).

[0055] Dashed lines illustrate the approximate extents of coverage areas 120 and 125, which are shown as approximately circular for purposes of illustration and explanation only. It should be clearly understood that coverage areas associated with gNBs, such as coverage areas 120 and 125, may have other shapes, including irregular shapes, depending on the configuration of the gNB and variations in the radio environment associated with natural and man-made obstacles.

[0056] As described in more detail below, one or more of the UEs 111-116 include circuitry, programming, or a combination thereof for UE-initiated cell switching. In certain embodiments, one or more of the gNBs 101-103 include circuitry, programming, or a combination thereof to support UE-initiated cell switching in a wireless communication system.

[0057] Although FIG. 1 shows one example of a wireless network, various changes may be made to FIG. 1. For example, the wireless network may include any number of gNBs and any number of UEs in any suitable arrangement. In addition, gNB 101 may communicate directly with any number of UEs and provide those UEs with wireless broadband access to network 130. Similarly, each gNB 102-103 may communicate directly with network 130 and provide the UEs with direct wireless broadband access to network 130. In addition, gNBs 101, 102, and / or 103 may provide access to other or additional external networks, such as an external telephone network or other type of data network.

[0058] 2A and 2B illustrate example wireless transmit and receive paths according to embodiments of the present disclosure. In the following description, transmit path 200 may be described as being implemented in a gNB (such as gNB 102) and receive path 250 may be described as being implemented in a UE (such as UE 116). However, it should be understood that receive path 250 may be implemented in a gNB and transmit path 200 may be implemented in a UE. In some embodiments, receive path 250 is configured to support UE-initiated cell handover in a wireless communication system as described in embodiments of the present disclosure.

[0059] The transmit path 200 includes a channel coding and modulation block 205, a serial to parallel (S to P) block 210, an inverse fast Fourier transform (IFFT) block of size N 215, a parallel to serial (P to S) block 220, an add cyclic prefix block 225, and an upconverter (UC) 230. The receive path 250 includes a downconverter (DC) 255, a remove cyclic prefix block 260, a serial to parallel (S to P) block 265, a fast Fourier transform (FFT) block of size N 270, a parallel to serial (P to S) block 275, and a channel decoding and demodulation block 280.

[0060] Although Figures 2A and 2B show one example of wireless transmission and reception paths, various changes may be made to Figures 2A and 2B. For example, the blocks may be arranged in a different order or arranged to operate simultaneously, additional blocks may be added, some blocks may be omitted, etc.

[0061] FIG3A shows an example gNB 102 according to an embodiment of the present disclosure. The embodiment of the gNB 102 shown in FIG3A is for illustration only, and the gNBs 101 and 103 of FIG1 may have the same or similar configurations. However, gNBs have a wide variety of configurations, and FIG3A does not limit the scope of the present disclosure to any particular implementation of the gNB.

[0062] As shown in Figure 3A, the gNB 102 includes multiple antennas 205a-205n, multiple transceivers 210a-210n, a controller / processor 225, a memory 230, and a backhaul or network interface 235.

[0063] The transceivers 210a-210n receive incoming RF signals from the antennas 205a-205n, such as signals transmitted by UEs in the network 100. The transceivers 210a-210n downconvert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are processed by receive (RX) processing circuits in the transceivers 210a-210n and / or the controller / processor 225, which generate processed baseband signals by filtering, decoding, and / or digitizing the baseband or IF signals. The controller / processor 225 may further process the baseband signals.

[0064] Transmit (TX) processing circuitry in the transceivers 310a-310n and / or the controller / processor 325 receives analog or digital data (such as voice data, web data, email, or interactive video game data) from the controller / processor 325. The TX processing circuitry encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The transceivers 310a-310n up-convert the baseband or IF signal to an RF signal that is transmitted via the antennas 305a-305n.

[0065] The controller / processor 325 may include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller / processor 325 may control the reception of UL channels or signals and the transmission of DL channels or signals by the transceivers 310a-310n in accordance with well-known principles. The controller / processor 325 may also support additional functionality, such as more advanced wireless communication functionality. For example, the controller / processor 325 may support beamforming or directional routing operations, in which outgoing / incoming signals from / to multiple antennas 305a-305n are weighted differently to effectively direct the outgoing signals in a desired direction. The controller / processor 325 may support any of a variety of other functions in the gNB 102.

[0066] The controller / processor 325 is also capable of executing programs and other processes resident in the memory 330, such as an OS and processes for supporting UE-initiated cell handovers, for example, as discussed in more detail below. The controller / processor 325 can move data into or out of the memory 330 as required by the executing process.

[0067] The controller / processor 325 is also coupled to the backhaul or network interface 235. The backhaul or network interface 335 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 335 can support communication over any suitable wired or wireless connection. For example, when the gNB 102 is implemented as part of a cellular communication system (such as a cellular communication system supporting 5G / NR, LTE, or LTE-A), the interface 335 can allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 335 can allow the gNB 102 to communicate with a larger network (such as the Internet) over a wired or wireless local area network or over a wired or wireless connection. The interface 335 includes any suitable structure that supports communication over a wired or wireless connection, such as Ethernet or a transceiver.

[0068] Memory 330 is coupled to controller / processor 325. A portion of memory 330 may include RAM, and another portion of memory 330 may include flash memory or other ROM.

[0069] Although FIG3A shows one example of a gNB 102, various changes may be made to FIG3A. For example, the gNB 102 may include any number of each of the components shown in FIG3A. Furthermore, various components in FIG3A may be combined, further subdivided, or omitted, and additional components may be added as required.

[0070] FIG3B shows an example UE 116 according to an embodiment of the present disclosure. The embodiment of UE 116 shown in FIG3B is for illustration only, and UEs 111-115 of FIG1 may have the same or similar configurations. However, UEs have a variety of configurations, and FIG3B does not limit the scope of the present disclosure to any particular implementation of the UE.

[0071] 3B , UE 116 includes antenna 306, transceiver 311, and microphone 320. UE 116 also includes speaker 331, processor 340, input / output (I / O) interface (IF) 345, input 350, display 355, and memory 360. Memory 360 includes operating system (OS) 361 and one or more applications 362.

[0072] Transceiver 311 receives incoming RF signals from antenna 306 transmitted by a gNB of network 100. Transceiver 311 downconverts the incoming RF signals to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is processed by RX processing circuitry in transceiver 311 and / or processor 340, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuitry sends the processed baseband signal to speaker 331 (such as for voice data) or is processed by processor 340 (such as for web browsing data).

[0073] The TX processing circuit in the transceiver 311 and / or the processor 340 receives analog or digital voice data from the microphone 320, or receives other outgoing baseband data (such as web data, email, or interactive video game data) from the processor 340. The TX processing circuit encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The transceiver 311 up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna 306.

[0074] The processor 340 may include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 to control the overall operation of the UE 116. For example, the processor 340 may control the transceiver 311 to receive DL channels or signals and to transmit UL channels or signals according to well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[0075] The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as processes for UE-initiated cell handovers, as discussed in more detail below. The processor 340 can move data into or out of the memory 360 as needed for the executing process. In some embodiments, the processor 340 is configured to execute applications 362 based on the OS 361 or in response to signals received from the gNB or operator. The processor 340 is also coupled to the I / O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptops and handheld computers. The I / O interface 345 is the communication path between these accessories and the processor 340.

[0076] Processor 340 is also coupled to input 350, including, for example, a touch screen, a keypad, etc., and display 355. An operator of UE 116 may use input 350 to enter data into UE 116. Display 355 may be a liquid crystal display, a light emitting diode display, or other display capable of presenting text and / or at least limited graphics, such as from a website.

[0077] Memory 360 is coupled to processor 340. A portion of memory 360 may include random access memory (RAM), and another portion of memory 360 may include flash memory or other read-only memory (ROM).

[0078] Although FIG. 3B shows an example of UE 116, various changes may be made to FIG. 3B. For example, various components in FIG. 3B may be combined, further subdivided, or omitted, and additional components may be added according to specific needs. As a specific example, processor 340 may be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). In another example, transceiver 311 may include any number of transceivers and signal processing chains, and may be connected to any number of antennas. In addition, although FIG. 3B shows UE 116 configured as a mobile phone or smart phone, the UE may be configured to operate as other types of mobile or fixed devices.

[0079] In the present disclosure, a beam may be determined by any of the following:

[0080] - Transmission Configuration Indication (TCI) state to establish a Quasi Co-location (QCL) relationship,

[0081] - the spatial relationship between source reference signals (e.g., synchronization signal blocks (SS / PBCH blocks or SSBs)),

[0082] - Channel State Information Reference Signal (CSI-RS) and Target Reference Signal,

[0083] - Spatial relationship information to establish association with source reference signals (such as SSB, CSI-RS), or

[0084] - Sounding Reference Signal (SRS). In either case, the ID of the source reference signal identifies the beam.

[0085] The TCI status and / or spatial relation reference RS may determine the spatial Rx filter for reception of a downlink channel at the UE, or the spatial Tx filter for transmission of an uplink channel from the UE. The TCI status and / or spatial relation reference RS may determine the spatial Tx filter for transmission of a signal or a downlink channel from the gNB, or the spatial Rx filter for reception of a signal or an uplink channel at the gNB.

[0086] FIG4A illustrates an example beam in a wireless system according to the present disclosure. The embodiment of the beam shown in FIG4A is for illustration only. Other embodiments of the beam may be used without departing from the scope of the present disclosure.

[0087] As shown in FIG4A , in a wireless system, a beam (401) for a device (404) can be characterized by a beam direction (402) and a beam width (403). For example, the device (404) transmits radio frequency (RF) energy in the beam direction and within the beam width. The device (404) receives RF energy in the beam direction and within the beam width. As shown in FIG4A , a device at point A (405) can receive from and transmit to the device (404) when point A is within the beam width and direction of the beam from the device (404). As shown in FIG4A , a device at point B (406) cannot receive from and transmit to the device (404) because point B is outside the beam width and direction of the beam from the device (404). Although FIG. 4A shows a two-dimensional (2D) beam for illustrative purposes, it will be apparent to one skilled in the art that the beam may be three-dimensional (3D), where the beam direction and beam width are defined in space. Although FIG. 4A shows one example of a wireless beam, various changes may be made to FIG. 4A. For example, the beam direction and beam width may be changed.

[0088] FIG4B shows an example of multiple beams in a wireless system according to the present disclosure. The embodiment of the beams shown in FIG4B is for illustration only. Other embodiments of the beams may be used without departing from the scope of the present disclosure.

[0089] As shown in FIG4B , in a wireless system, a device may transmit and / or receive on multiple beams. This is referred to as “multi-beam operation” and is shown in FIG4B . Although FIG4B shows the beams as 2D for illustrative purposes, it is apparent to one skilled in the art that the beams may be 3D, where the beams may be sent to or received from any direction in space.

[0090] Although FIG4B shows an example of multiple beams in a wireless system, various changes may be made to FIG4B. For example, the number of beams, beam directions, and beam directions may be changed.

[0091] FIG5 shows an example antenna block or array 500 according to an embodiment of the present disclosure. The embodiment of the antenna block or array 500 shown in FIG5 is for illustration only. Different embodiments of the antenna block or array 500 may be used without departing from the scope of the present disclosure.

[0092] The unit used for DL ​​signaling or UL signaling on a cell is called a slot and may include one or more symbols. The bandwidth (BW) unit is called a resource block (RB). One RB includes multiple subcarriers (SC). For example, a slot may have a duration of one millisecond, and a RB may have a bandwidth of 180kHz and include 12 SCs with an inter-SC spacing of 15kHz. A slot may be a full DL slot, or a full UL slot, or a mixed slot similar to a special subframe in a time division duplex (TDD) system.

[0093] DL signals include data signals conveying information content, control signals conveying DL control information (DCI), and reference signals (RS) also known as pilot signals. The gNB transmits data information or DCI through the corresponding physical DL shared channel (PDSCH) or physical DL control channel (PDCCH). PDSCH or PDCCH can be transmitted on a variable number of time slot symbols including one time slot symbol. The spatial setting for PDCCH reception can be indicated to the UE based on the configuration of the value of the transmission configuration indication state (TCI state) of the control resource set (CORESET) of the UE to receive the PDCCH. The UE can be indicated by the spatial setting of PDSCH reception based on the configuration of a higher layer or based on the activation or indication of the MACCE or based on the indication of the DCI format of the PDSCH reception based on the value of the scheduling TCI state. The gNB can configure the UE to receive signals on a cell within the DL bandwidth part (BWP) of the cell DL BW.

[0094] The gNB transmits one or more of multiple types of RS including channel state information RS (CSI-RS) and demodulation RS (DMRS). CSI-RS is mainly used for UE to perform measurements and provide channel state information (CSI) to the gNB. For channel measurement, non-zero power CSI-RS (NZP CSI-RS) resources are used. For interference measurement report (IMR), CSI interference measurement (CSI-IM) resources associated with zero power CSI-RS (ZPCSI-RS) configuration are used. The CSI process consists of NZP CSI-RS and CSI-IM resources. The UE can determine the CSI-RS transmission parameters through DL control signaling or higher layer signaling (such as RRC signaling from the gNB). The transmission instance of CSI-RS can be indicated by DL control signaling or configured by high layer signaling. DMRS is transmitted only in the BW of the corresponding PDCCH or PDSCH, and the UE can use DMRS to demodulate data or control information.

[0095] The UL signal also includes a data signal conveying information content, a control signal conveying UL control information (UCI), a DMRS associated with data or UCI demodulation, a sounding RS (SRS) enabling the gNB to perform UL channel measurement, and a random access (RA) preamble enabling the UE to perform random access. The UE transmits data information or UCI through the corresponding physical UL shared channel (PUSCH) or physical UL control channel (PUCCH). The PUSCH or PUCCH can be transmitted on a variable number of time slot symbols including one time slot symbol. The gNB can configure the UE to transmit the signal on a cell within the UL BWP of the cell UL BW.

[0096] UCI includes hybrid automatic repeat request acknowledgement (HARQ-ACK) information indicating correct or incorrect detection of a data transport block (TB) in the PDSCH, a scheduling request (SR) indicating whether the UE has data in the UE's buffer, and a CSI report that enables the gNB to select appropriate parameters for PDSCH or PDCCH transmission to the UE. The HARQ-ACK information can be configured with a smaller granularity than per TB and can be per data code block (CB) or per data CB group, where a data TB includes multiple data.

[0097] The CSI report from the UE may include a channel quality indicator (CQI) that informs the gNB of the maximum modulation and coding scheme (MCS) for the UE to detect a data TB with a predetermined block error rate (BLER) such as 10% BLER, a precoding matrix indicator (PMI) that informs the gNB how to combine signals from multiple transmitter antennas according to the multiple input multiple output (MIMO) transmission principle, and a rank indicator (RI) that indicates the transmission rank of the PDSCH. The UL RS includes DMRS and SRS. DMRS is transmitted only in the BW of the corresponding PUSCH or PUCCH transmission. The gNB can use DMRS to demodulate the information in the corresponding PUSCH or PUCCH. SRS is sent by the UE to provide UL CSI to the gNB, and for TDD systems, SRS transmission may also provide PMI for DL ​​transmission. In addition, in order to establish synchronization or an initial higher layer connection with the gNB, the UE may send a physical random access channel (PRACH).

[0098] Rel-14 LTE and Rel-15 NR support up to 32 CSI-RS antenna ports, which enables an eNB or gNB to be equipped with a large number of antenna elements (such as 64 or 128). Multiple antenna elements can then be mapped to one CSI-RS port. For mmWave bands, although the number of antenna elements may be larger for a given form factor, the number of CSI-RS ports that may correspond to the number of digital precoding ports may be limited due to hardware constraints (such as the feasibility of installing a large number of ADCs / DACs at mmWave frequencies), as shown in Figure 5. One CSI-RS port can then be mapped to a large number of antenna elements that can be controlled by a set of analog phase shifters 501. One CSI-RS port can then correspond to one subarray that produces a narrow analog beam through analog beamforming 505. The analog beam can be configured to scan a wider range of angles (520) by changing the phase shifter set between symbols or time slots / subframes. The number of subarrays (equal to the number of RF chains) is proportional to the number of CSI-RS ports. The digital beamforming unit 510 is the same as The analog beams are linearly combined to further increase the precoding gain. While the analog beams are wideband (and therefore not frequency selective), the digital precoding can vary across frequency subbands or resource blocks. Receiver operation can be similarly envisioned.

[0099] Since the above-described systems utilize multiple simulated beams for transmission and reception (where one or a small number of simulated beams are selected from a large number of simulated beams, for example, after a training duration that is performed occasionally or periodically), the term "multi-beam operation" is used to refer to the entire system aspect. For the purpose of description, this includes indicating an assigned DL or UL transmit (TX) beam (also referred to as "beam indication"), measuring at least one reference signal used to calculate and perform beam reporting (also referred to as "beam measurement" and "beam reporting", respectively), and receiving DL or UL transmissions via selection of a corresponding receive (RX) beam.

[0100] The above system is also applicable to higher frequency bands, such as >52.6 GHz. In this case, the system can use only analog beams. Due to the O2 absorption loss near 60 GHz (~10 dB additional loss per 100 m distance), more and narrower analog beams (and therefore more radiators in the array) are needed to compensate for the additional path loss.

[0101] Rel-17 introduces a unified TCI framework, where a unified or primary or main or indicated TCI state is signaled or indicated to the UE. The unified or primary or main or indicated TCI state can be one of the following:

[0102] 1. In case of joint TCI state indication, where the same beam is used for DL ​​and UL channels, the joint TCI state may be used for at least UE-specific DL channels and UE-specific UL channels.

[0103] 2. In case of separate TCI state indication, where different beams are used for DL ​​and UL channels, the DL TCI state may be used at least for the UE-dedicated DL channel.

[0104] 3. In case of separate TCI state indication, where different beams are used for DL ​​and UL channels, the UL TCI state may be used at least for the UE-specific UL channel.

[0105] The unified (primary or primary or indicated) TCI state is the DL or joint TCI state for UE-specific reception on PDSCH / PDCCH and the CSI-RS to which the indicated TCI state is applied and / or the UL or joint TCI state for PUSCH, PUCCH based on dynamic grant / configured grant, and the SRS to which the indicated TCI state is applied.

[0106] The unified TCI framework is applicable to intra-cell beam management, where the TCI state has a source RS that is directly or indirectly associated with the SSB of the serving cell through a quasi-co-location relationship (e.g., a spatial relationship) (e.g., the TCI state is associated with the TRP of the serving cell). The unified TCI state framework is also applicable to inter-cell beam management, where the TCI state may have a source RS that is directly or indirectly associated with the SSB of a cell having a physical cell identifier (PCI) different from the PCI of the serving cell through a quasi-co-location relationship (e.g., a spatial relationship) (e.g., the TCI state is associated with the TRP of a cell having a PCI different from the PCI of the serving cell). In Rel-17, UE-dedicated channels may be received and / or sent using a TCI state associated with a cell having a PCI different from the PCI of the serving cell. Whereas common channels may be received and / or transmitted using a TCI state associated with the serving cell (e.g., not associated with a cell having a PCI different from the PCI of the serving cell). In one example, the common channel may include a channel carrying system information (eg, System Information Block 1 (SIB1)), where DL assignments are carried by DCI in a PDCCH with a CRC scrambled by the SI-RNTI and sent in a Type0-PDCCH CSS set.

[0107] In another example, common channels may include channels that carry other system information, where DL assignments are carried by DCI in a PDCCH with a CRC scrambled by the SI-RNTI and sent in a Type0A-PDCCH CSS set.

[0108] In another example, the common channel may include a channel carrying paging or short messages, where the DL assignment is carried by DCI in a PDCCH with a CRC scrambled by the P-RNTI and sent in a Type2-PDCCH CSS set.

[0109] In another example, the common channel may include a channel carrying RACH related channels, where DL assignments or UL grants are carried by DCI in a PDCCH with a CRC scrambled by the RA-RNTI or TC-RNTI and sent in a Type 1-PDCCH CSS set.

[0110] A DL-related DCI format (e.g., DCI format 1_1 or DCI format 1_2) with or without DL allocation may indicate a TCI state code point to the UE via the field "Transmit Configuration Indication", where the TCI state code point may be one of the following: (1) DL TCI state; (2) UL TCI state; (3) joint TCI state; or (4) a pair of DL TCI state and UL TCI state. The TCI state code point may be activated by media access control-control element (MAC CE) signaling.

[0111] A quasi-co-located (QCL) relationship may be quasi-located with respect to one or more of the following relationships [38.214 - Section 5.1.5]:

[0112] - Type A, {Doppler shift, Doppler spread, average delay, delay spread}

[0113] - Type B, {Doppler shift, Doppler spread}

[0114] - Type C, {Doppler shift, average delay}

[0115] -Type D, {Spatial Rx Parameters}

[0116] In addition, the quasi-co-location relationship can also provide a spatial relationship for the UL channels, for example, the DL source reference signal provides information about the spatial domain filter to be used for the UL transmission, or the UL source reference signal provides the spatial domain filter to be used for the UL transmission, for example, the same spatial domain filter is used for the UL source reference signal and the UL transmission.

[0117] The unified (primary or primary or indicated) TCI state applies to at least UE-specific DL and UL channels. The unified (primary or primary or indicated) TCI state may also apply to other DL and / or UL channels and / or signals, such as non-UE-specific channels and sounding reference signals (SRS).

[0118] In Rel-18, new work items have been agreed to further enhance mobility in NR. "When a UE moves from the coverage area of ​​one cell to another, at some point a serving cell change needs to be performed. Currently, serving cell changes are triggered by L3 measurements and are done through a reconfiguration triggered by RRC signaling with synchronization for the change of PCell and PSCell, and release-addition for SCell when applicable. All cases involve a full L2 (and L1) reset, resulting in longer latency, greater overhead, and longer outage time than beam switch mobility. The goal of L1 / L2 mobility enhancements is to enable serving cell changes via L1 / L2 signaling to reduce latency, overhead, and outage time." Allowing the serving cell to be changed seamlessly using L1 / L2 mechanisms reduces handover latency and results in more robust operation (fewer dropped calls). In this disclosure, we look at mechanisms for handovers triggered by beam switching from the beam of one cell to the beam of another cell.

[0119] FIG6 shows an example of beam changing 600 from a TRP of a serving cell to a TRP of a cell having a PCI different from the PCI of the serving cell according to the present disclosure. The embodiment of beam changing shown in FIG6 is for illustration only. Other embodiments of beam changing may be used without departing from the present disclosure.

[0120] In Rel-17, a unified TCI state framework has been introduced to simplify the beam management process by reducing the delay and overhead associated with beam changes. Rel-17 also introduces inter-cell beam management, where at least UE dedicated channels can be received on a beam associated with a TRP that is associated with a PCI that is different from the PCI of the serving cell. In Rel-17, when the beam is changed from the TRP of the serving cell to the TRP of a cell with a PCI different from the PCI of the serving cell, the serving cell is not changed, as shown in Figure 6. Common channels continue to be received and transmitted on the beam associated with the serving cell.

[0121] In Rel-17, a unified or primary or main or indicated TCI state is signaled to the UE to indicate the beam to be used by the UE. RRC signaling configures the Rel-17 TCI state, where the TCI state can be configured as a DL or joint TCI state using the information element (DLorJoint-TCIState), or a UL TCI state using the information element (UL-TCIState). MAC signaling can activate one or more TCI code points. When the MAC CE activates one TCI state code point, the UE applies the TCI state associated with the activated code point after the beam application time. When the MAC CE activates more than one TCI code point, further DCI signaling may be used to indicate the TCI state code point to the UE. The unified TCI state may be signaled by a DCI format with DL allocation (e.g., a DL-related DCI format (e.g., DCI format 1_1 or DCI format 1_2)) or a DL-related DCI format without DL allocation (e.g., DCI format 1_1 or DCI format 1_2)).

[0122] To further enhance mobility, the UE may initiate a handover from a source cell to a target (or candidate) cell. The UE may notify the network (e.g., the source cell and / or the target (or candidate) cell) of the handover initiation, and the network may respond by completing the handover procedure. In this disclosure, we consider methods for the UE to notify the network of a UE-initiated handover and for the network to respond to UE-initiated handover requests and completion of dynamic cell handovers.

[0123] FIG7 shows an example of a UE configuration 700 according to the present disclosure. The embodiment of the UE configuration shown in FIG7 is for illustration only. Other embodiments of the UE configuration may be used without departing from the scope of the present disclosure.

[0124] In the following example, as shown in FIG7 , the UE is configured / updated by higher layer RRC signaling a set of TCI states with N elements. In one example, the DL and joint TCI states may be configured by a higher layer parameter DLorJoint-TCIState, where the number of DL and joint TCI states is · The UL TCI state may be configured by a higher layer parameter UL-TCIState, where the number of UL TCI states is The total number of configured TCI states can be given by: . In one example, the TCI state may be configured for a source serving cell and one or more target serving cells. DLorJoint-TCIState may include a DL or joint-TCI state belonging to a serving cell, for example, a source RS of the TCI state is associated with the serving cell (PCI of the serving cell). In addition, the DL or joint-TCI state may be associated with a cell having a PCI different from the PCI of the serving cell, for example, a source RS of the TCI state is associated with a cell having a PCI different from the PCI of the serving cell. UL-TCIState may include a UL TCI state belonging to a serving cell, for example, a source RS of the TCI state may be associated with the serving cell (PCI of the serving cell). In addition, the UL TCI state may be associated with a cell having a PCI different from the PCI of the serving cell, for example, a source RS of the TCI state may be associated with a cell having a PCI different from the PCI of the serving cell.

[0125] MAC CE signaling may include M from a set of N TCI states ( ) TCI states or a subset of TCI state code points, where the code point is signaled in the "Transmit Configuration Indication" field of the DCI for indication of the TCI state. The code point may contain one TCI state (e.g., DL TCI state or UL TCI state or joint (DL and UL) TCI state). Alternatively, the code point may contain two TCI states (e.g., DL TCI state and UL TCI state). L1 control signaling (i.e., downlink control information (DCI)) may update the TCI state of the UE, where the DCI may contain, for example, a "Transmit Configuration Indication" (beam indication) field with m bits (such that ), the TCI state may correspond to a code point signaled by the MAC CE. The DCI for indicating the TCI state may be a DL-related DCI format (eg, DCI format 1_1 or DCI format 1_2), with or without DL allocation.

[0126] The TCI state may be associated with an SSB or reference signal of a serving cell via a QCL relationship, or an SSB or reference signal associated with a PCI different from the PCI of the serving cell. A QCL relationship with an SSB may be a direct QCL relationship, where the source RS of the QCL state (e.g., for a QCL type D relationship or a spatial relationship) is the SSB. A QCL relationship with an SSB may be an indirect QCL relationship, where the source RS (e.g., for a QCL type D relationship or a spatial relationship) may be a reference signal, and the reference signal has an SSB as its source (e.g., for a QCL type D relationship or a spatial relationship). An indirect QCL relationship with an SSB may involve a chain of QCL or spatial relationships of more than one reference signal.

[0127] In one embodiment, the dynamic switching of the serving cell is based on the TCI status indication, as shown in FIG8 .

[0128] FIG8 shows an example method 800 for switching based on TCI state indication according to the present disclosure. The embodiment of the switching method shown in FIG8 is for illustration only. One or more components shown in FIG8 may be implemented in a dedicated circuit configured to perform the functions, or one or more components may be implemented by one or more processors that execute instructions to perform the functions. Other embodiments of the switching method may be used without departing from the scope of the present disclosure.

[0129] In step 810 of FIG. 8 , handover preparation occurs between a source cell 801 and a target (or candidate) cell 802. The source cell 801 may be a serving cell associated with a physical cell identity (PCI). The target (or candidate) cell 802 may be a second cell associated with a PCI different from the PCI of the serving cell (source cell). There may be one or more target (or candidate) cells, each of which may have its own PCI. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI different from the PCIs of other target (or candidate) cells. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have the same PCI as the PCIs of other target (or candidate) cells. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have the same PCI as the PCIs of other target (or candidate) cells. In one example, if there are more than one target (or candidate) cell, each subset of the target (or candidate) cells may have the same PCI as the PCIs of other target (or candidate) cells in the same subset, and other subsets of the target (or candidate) cells may have different PCIs.

[0130] In one example, handover preparation may include the exchange of reference signals between cells involved in a potential handover. For example, the reference signal may be a measurement reference signal, where the measurement reference signal is used for measurement reporting from the UE. The measurement signal may be used, for example, to identify a new candidate beam in a serving (e.g., source cell) or target (or candidate) cell. The measurement signal may be used, for example, to determine whether a handover from the source cell to the target (or candidate) cell should be triggered or performed. The measurement metric regarding the measurement reference signal may be L1-reference signal received power (L1-RSRP), a signal to interference and noise ratio (SINR) derived based on the measurement reference signal, a block error rate (BLER), a channel quality indicator (CQI), L3-RSRP (where L3-RSRP is a long-term average (e.g., exponential average) of L1-RSRP), or some other quality metric determined based on the measurement reference signal. The measurement reference signal may include a DL measurement reference signal sent from a network (e.g., a gNB or TRP of a source cell or target (or candidate) cell), where the measurement may be performed in the UE and reported to the network in a measurement report. The measurement reference signal may include an UL measurement reference signal (e.g., SRS) sent by the UE, where the measurement is performed in the network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). In one example, the measurement reference signal may be used as a source reference signal.

[0131] In another example, the reference signal may be a source reference signal, where the source reference signal may be used to determine the source of a quasi co-location (QCL) in a TCI state (e.g., a source RS of QCL-TypeA or QCL-TypeB or QCL-TypeC or QCL-TypeD); or determine the source of a spatial relationship (e.g., determining a spatial relationship receive filter or a spatial relationship transmit filter). The source reference signal may include a DL reference signal sent from a network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). The source reference signal may include a UL reference signal (e.g., an SRS) sent by a UE. In one example, the source reference signal may be used as a measurement reference signal.

[0132] In one example, a reference signal (e.g., a measurement reference signal or a source reference signal) may be a synchronization signal block (SSB) (synchronization signal / physical broadcast channel (PBCH) block), where the SSB may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the association may be performed by including the PCI in a configuration of an SSB resource or an information element (IE) including the SSB resource. In another example, the association may be performed by configuration of the SSB resource as part of a configuration of a cell associated with the PCI.

[0133] In another example, the reference signal may be a channel state information reference signal (CSI-RS). The CSI-RS may be, for example, a CSI-RS for mobility (e.g., for handover), or a CSI-RS for beam management, or a CSI-RS for tracking, or a CSI-RS for CSI acquisition. The CSI-RS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of the serving cell (e.g., a target (or candidate) cell). In one example, the association may be through a QCL relationship with an SSB, or a CSI-RS associated with a PCI of a cell. In another example, the association may be performed by including the PCI in the configuration of the CSI-RS resources or in an information element (IE) including the CSI-RS resources. In another example, the association may be performed by configuration of the CSI-RS resources as part of the configuration of the cell associated with the PCI.

[0134] In another example, the reference signal may be a sounding reference signal (SRS), where the SRS is sent by the UE. In one example, the SRS may be an SRS resource for beam management. In another example, the SRS may be an SRS resource for a codebook. In another example, the SRS may be an SRS resource for a non-codebook. In another example, the SRS may be an SRS resource for antenna switching. In another example, the SRS may be an SRS resource for mobility (e.g., for switching). In one example, the SRS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the SRS may not be associated with the PCI of a cell (e.g., the SRS may be sent by a UE and may be received by any cell). In one example, the association may be through a QCL relationship or spatial relationship with an SSB or CSI-RS or SRS associated with the PCI of the cell. In another example, the association may be performed by including the PCI in the configuration of the SRS resource or in an information element (IE) including the SRS resource. In another example, the association may be made through configuration of SRS resources as part of the configuration of the cell associated with the PCI.

[0135] In one example, handover preparation may include exchanging transmission configuration indication (TCI) states between cells involved in a potential handover. For example, the TCI state may include a DL or Joint-TCI state (DLorJoint-TCIState), which includes, for example, one or more of the following: (1) TCI state ID; (2) first QCL information; (3) second QCL information; (4) UL power control ID; (5) path loss reference signal ID; and (6) associated PCI (or, the associated PCI may be included in the QCL information). QCL-Info may include (1) serving cell index; (2) BWP ID; (3) reference signal ID (e.g., CSI-RS resource ID or SSB index); (4) QCL type (e.g., type A, type B, type C, or type D); and (5) PCI index, or, the PCI index may be part of the reference signal ID.

[0136] In another example, the TCI state may include a UL TCI state (UL-TCIState), which includes, for example, one or more of the following: (1) a TCI state ID; (2) a serving cell index; (3) a reference signal ID (e.g., a CSI-RS resource ID or an SSB index or an SRS resource ID); (4) a PCI index, or the PCI index may be part of the reference signal ID; (5) a UL power control ID; and (6) a path loss reference signal ID.

[0137] At step 820 of FIG. 8 , the network performs RRC (re) configuration to UE 803. For example, the reconfiguration message may include information related to one or more target (or candidate) cells. For example, the information may include one or more of a reference signal (e.g., a measurement reference signal or a source reference signal as described above) of the target (or candidate) cell or a TCI state of the target (or candidate) cell, as described above.

[0138] At step 830 of FIG. 8 , UE 803 responds with RRC (re)configuration complete.

[0139] At step 840 of FIG. 8 , UE 803 performs measurements on the configured measurement reference signals of the source cell 801 and one or more target (or candidate) cells. The UE may provide a measurement report to the source cell. The measurement report may include one or more pairs of: (1) a measurement reference signal ID (e.g., a measurement reference signal ID of the source cell or the target (or candidate) cell); (2) a quality metric (e.g., L1-RSRP, SINR, BLER, CQI, L3-RSRP, etc. as described above). The measurement report may include measurements only from the source cell, or only from the target (or candidate) cell, or from the source cell and the target (or candidate) cell, or from one or more target (or candidate) cells, or from the source cell and one or more target (or candidate) cells. The number of cells in the measurement report may be limited (e.g., by system specification and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). The number of measurement pairs (e.g., measurement pairs per cell) in a measurement report may be limited (e.g., by system specification and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). The L1 control signaling may be a DL Control Information (DCI) signal. When multiple measurement pairs are reported, differential signaling (reporting) may be used. For example, the metric for a first pair (e.g., the first pair in the measurement report or the first pair associated with a cell in the measurement report) may be an absolute value, which is the pair with the best beam metric (e.g., in the measurement report or for each cell in the measurement report). Other pairs in the same report (e.g., across all cells or per cell) may have, for example, relative to the metric of the first pair (e.g., the first pair in the measurement report or the first pair associated with a cell in the measurement report) (or, alternatively, the metric of the previous pair). The second pair (if any) can have a lower metric than the first pair. dB is the measure of The third pair (if present) may have a lower metric than the first pair (or optionally the second pair) dB is the measure of Being signaled, and so on.

[0140] In one example, the measurement report may be configured periodically. In one example, the measurement report may be configured semi-persistently using a dynamic signal (e.g., via MAC CE or L1 control) to activate or deactivate the transmission of the measurement report. In one example, the measurement report may be triggered aperiodically using a dynamic signal (e.g., via MAC CE or L1 control). In one example, the measurement report may be UE initiated; for example, the UE may send a scheduling request for UL resources to send the measurement report, or the UE may send the measurement report in a configured grant (a grant configured in type 1 or type 2) resource, or the UE may send the measurement report using a random access procedure (e.g., a type 1 random access procedure or a type 2 random access procedure).

[0141] In one example, the measurement report may be reported in uplink control information (UCI) in a physical uplink control channel (PUCCH). In one example, if the PUCCH overlaps with a physical uplink shared channel (PUSCH), the PUCCH may not be sent and the UCI may be multiplexed into the PUSCH. In one example, the measurement report may be reported in the UCI in the PUSCH. In one example, the measurement report may be reported in a MAC CE. In one example, the measurement report may be reported in a single-stage UCI. In another example, the measurement report may be reported in a two-stage UCI. For example, the first stage may include information about the number of measurement pairs (e.g., measurement pairs for each cell) or the number of cells with reported measurements, and the measurement pairs may be reported in the second stage of the UCI.

[0142] At step 850 of Figure 8, the source cell 801 determines which TCI states to activate. For example, the TCI state to be activated may belong to the source cell or to one or more target (or candidate) cells. In one example, the number of cells with an activated TCI state may be limited (e.g., by system specifications and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). In one example, the activated TCI state may be on the source cell and additional target (or candidate) cells. In one example, the activated TCI state may be indicated by MAC CE signaling, where the MAC CE signaling activates the TCI state code point, as mentioned above. In one example, some or all of the activated TCI state code points may belong to the target (or candidate) cell. In one example, a single code point may be activated and therefore applied after a beam application delay.

[0143] At step 860 of Figure 8, the source cell 801 makes a decision about handover to the target (or candidate) cell 802 based on the measurement report from the UE 803 (step 840). In order to trigger the handover to the target (or candidate) cell, the network may indicate to the UE 803 the beam associated with the target (or candidate) cell 802 (TCI state).

[0144] At step 870 of Figure 8, a TCI status code point is indicated to UE 803. The TCI status code point may be indicated by a DL-related DCI format, where the DL-related DCI format may be one of DCI format 1_1 or DCI format 1_2. The DCI format may include a "transmission configuration indication" field to indicate the code point of the TCI status code point activated by the MAC CE. In one example, the DCI format may include a DL allocation, and in another example, the DCI format may not include a DL allocation. In one example, the indicated TCI status code point is associated with a target (or candidate) cell. In one example, the TCI status code point may be indicated in the MAC CE, as shown in Figure 8. This may trigger a handover to the target (or candidate) cell after a beam application delay, as shown in Figure 9.

[0145] FIG9 illustrates an example method 900 for switching to a target (or candidate) cell after a beam application delay according to the present disclosure. The embodiment of the switching method shown in FIG9 is for illustration only. Other embodiments of the switching method may be used without departing from the scope of the present disclosure.

[0146] Although Figure 9 shows one example of a method 900 for switching to a target (or candidate) cell after a beam application delay, various changes may be made to Figure 9. For example, although shown as a series of steps, the various steps in Figure 9 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0147] At step 870a of FIG. 8 , information is exchanged between the source cell 801 and the target (or candidate) cell 802 to complete the handover at the beam application time.

[0148] Although Figure 8 shows one example of a switching method 800 based on TCI status indication, various changes may be made to Figure 8. For example, although shown as a series of steps, the various steps in Figure 8 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0149] In one embodiment, the dynamic switching of the serving cell is based on the TCI status indication and the dynamic cell switching signal is shown in FIG. 10 .

[0150] FIG. 10 shows an example method 1000 for switching based on TCI state indication according to the present disclosure. The embodiment of the switching method shown in FIG. 10 is for illustration only. One or more components shown in FIG. 10 may be implemented in a dedicated circuit configured to perform the functions, or one or more components may be implemented by one or more processors that execute instructions to perform the functions. Other embodiments of the switching method may be used without departing from the scope of the present disclosure.

[0151] At step 1010 of FIG. 10 , handover preparation occurs between a source cell 1001 and a target (or candidate) cell 1002. The source cell 1001 may be a serving cell associated with a physical cell identity (PCI). The target (or candidate) cell 1002 may be a second cell associated with a PCI different from the PCI of the serving cell (source cell). There may be one or more target (or candidate) cells, each of which may have its own PCI. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI different from the PCI of the other target (or candidate) cells. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI that is the same as the PCI of the other target (or candidate) cells. In one example, if there is more than one target (or candidate) cell, each subset of target (or candidate) cells may have the same PCI as the PCIs of other target (or candidate) cells in the same subset, and other subsets of target (or candidate) cells may have different PCIs.

[0152] In one example, handover preparation may include the exchange of reference signals between cells involved in a potential handover. For example, the reference signal may be a measurement reference signal, where the measurement reference signal is used for measurement reporting from the UE. The measurement signal may be used, for example, to identify a new candidate beam in a serving (e.g., source cell) or target (or candidate) cell. The measurement signal may be used, for example, to determine whether a handover from the source cell to the target (or candidate) cell should be triggered or performed. The measurement metric regarding the measurement reference signal may be L1-reference signal received power (L1-RSRP), a signal to interference and noise ratio (SINR) derived based on the measurement reference signal, a block error rate (BLER), a channel quality indicator (CQI), L3-RSRP (where L3-RSRP is a long-term average (e.g., exponential average) of L1-RSRP), or some other quality metric determined based on the measurement reference signal. The measurement reference signal may include a DL measurement reference signal sent from a network (e.g., a gNB or TRP of a source cell or target (or candidate) cell), where the measurement may be performed in the UE and reported to the network in a measurement report. The measurement reference signal may include an UL measurement reference signal (e.g., SRS) sent by the UE, where the measurement is performed in the network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). In one example, the measurement reference signal may be used as a source reference signal.

[0153] In another example, the reference signal may be a source reference signal, where the source reference signal may be used to determine the source of quasi co-location (QCL) in the TCI state (e.g., the source RS of QCL-TypeA or QCL-TypeB or QCL-TypeC or QCL-TypeD); or determine the source of the spatial relationship (e.g., determine the spatial relationship receiving filter or the spatial relationship transmitting filter). The source reference signal may include a DL reference signal sent from the network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). The source reference signal may include a UL reference signal (e.g., SRS) sent by the UE. In one example, the source reference signal may be used as a measurement reference signal.

[0154] In one example, a reference signal (e.g., a measurement reference signal or a source reference signal) may be a synchronization signal block (SSB) (synchronization signal / physical broadcast channel (PBCH) block), where the SSB may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the association may be performed by including the PCI in a configuration of an SSB resource or an information element (IE) including the SSB resource. In another example, the association may be performed by configuration of the SSB resource as part of a configuration of a cell associated with the PCI.

[0155] In another example, the reference signal may be a channel state information reference signal (CSI-RS). The CSI-RS may be, for example, a CSI-RS for mobility (e.g., for handover), or a CSI-RS for beam management, or a CSI-RS for tracking, or a CSI-RS for CSI acquisition. The CSI-RS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of the serving cell (e.g., a target (or candidate) cell). In one example, the association may be through a QCL relationship with an SSB, or a CSI-RS associated with a PCI of a cell. In another example, the association may be performed by including the PCI in the configuration of the CSI-RS resources or in an information element (IE) including the CSI-RS resources. In another example, the association may be performed by configuration of the CSI-RS resources as part of the configuration of the cell associated with the PCI.

[0156] In another example, the reference signal may be a sounding reference signal (SRS), where the SRS is sent by the UE. In one example, the SRS may be an SRS resource for beam management. In another example, the SRS may be an SRS resource for a codebook. In another example, the SRS may be an SRS resource for a non-codebook. In another example, the SRS may be an SRS resource for antenna switching. In another example, the SRS may be an SRS resource for mobility (e.g., for switching). In one example, the SRS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the SRS may not be associated with the PCI of a cell (e.g., the SRS may be sent by a UE and may be received by any cell). In one example, the association may be through a QCL relationship or spatial relationship with an SSB or CSI-RS or SRS associated with the PCI of the cell. In another example, the association may be performed by including the PCI in the configuration of the SRS resource or in an information element (IE) including the SRS resource. In another example, the association may be made through configuration of SRS resources as part of the configuration of the cell associated with the PCI.

[0157] In one example, handover preparation may include the exchange of transmission configuration indication (TCI) states between cells involved in a potential handover. For example, the TCI state may include a DL or Joint-TCI state (DLorJoint-TCIState), which includes, for example, one or more of the following: (1) TCI state ID; (2) first QCL information; (3) second QCL information; (4) UL power control ID; (5) path loss reference signal ID; and (6) associated PCI (or, the associated PCI may be included in the QCL information). QCL-Info may include (1) serving cell index; (2) BWP ID; (3) reference signal ID (e.g., CSI-RS resource ID or SSB index); (4) QCL type (e.g., type A, type B, type C, or type D); and (5) PCI index, or, the PCI index may be part of the reference signal ID.

[0158] In another example, the TCI state may include a UL TCI state (UL-TCIState), which includes, for example, one or more of the following: (1) a TCI state ID; (2) a serving cell index; (3) a reference signal ID (e.g., a CSI-RS resource ID or an SSB index or an SRS resource ID); (4) a PCI index, or the PCI index may be part of the reference signal ID; (5) a UL power control ID; and (6) a path loss reference signal ID.

[0159] At step 1020 of FIG. 10 , the network performs RRC (re) configuration to UE 1003. For example, the reconfiguration message may include information related to one or more target (or candidate) cells. For example, the information may include one or more of a reference signal (e.g., a measurement reference signal or a source reference signal as described above) of the target (or candidate) cell or a TCI state of the target (or candidate) cell, as described above.

[0160] At step 1030 of FIG. 10 , UE 1003 responds with RRC (re)configuration complete.

[0161] In step 1040 of FIG. 10 , UE 1003 performs measurements on the configured measurement reference signals of the source cell and one or more target (or candidate) cells. UE 1003 may provide a measurement report to the source cell. The measurement report may include one or more pairs of: (1) a measurement reference signal ID (e.g., a measurement reference signal ID of the source cell or the target (or candidate) cell); (2) a quality metric (e.g., L1-RSRP, SINR, BLER, CQI, L3-RSRP as described above). The measurement report may include measurements from only the source cell, or only the target (or candidate) cell, or from the source cell and the target (or candidate) cell, or from one or more target (or candidate) cells, or from the source cell and one or more target (or candidate) cells. The number of cells in the measurement report may be limited (e.g., by system specification and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). The number of measurement pairs (e.g., measurement pairs per cell) in a measurement report may be limited (e.g., by system specification and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). The L1 control signaling may be a DL Control Information (DCI) signal. When multiple measurement pairs are reported, differential signaling (reporting) may be used. For example, the metric for a first pair (e.g., the first pair in the measurement report or the first pair associated with a cell in the measurement report) may be an absolute value. This may be the pair with the best beam metric (e.g., in the measurement report or for each cell in the measurement report). In another example, other pairs in the same report (e.g., across all cells or per cell) may have, for example, a metric relative to the metric of the first pair (e.g., the first pair in the measurement report or the first pair associated with a cell in the measurement report) (or, alternatively, the metric of the previous pair). dB step size. The second pair (if present) may have a lower metric than the first pair dB is the measure of The third pair (if present) may have a lower metric than the first pair (or optionally the second pair) dB is the measure of Being signaled, and so on.

[0162] In one example, the measurement report may be configured periodically. In one example, the measurement report may be configured semi-persistently using a dynamic signal (e.g., via MAC CE or L1 control) to activate or deactivate the transmission of the measurement report. In one example, the measurement report may be triggered aperiodically using a dynamic signal (e.g., via MAC CE or L1 control). In one example, the measurement report may be UE initiated; for example, the UE may send a scheduling request for UL resources to send the measurement report, or the UE may send the measurement report in a configured grant (a grant configured in type 1 or type 2) resource, or the UE may send the measurement report using a random access procedure (e.g., a type 1 random access procedure or a type 2 random access procedure).

[0163] In one example, the measurement report may be reported in uplink control information (UCI) in a physical uplink control channel (PUCCH). In one example, if the PUCCH overlaps with a physical uplink shared channel (PUSCH), the PUCCH may not be sent and the UCI may be multiplexed into the PUSCH. In one example, the measurement report may be reported in the UCI in the PUSCH. In one example, the measurement report may be reported in a MAC CE. In one example, the measurement report may be reported in a single-stage UCI. In another example, the measurement report may be reported in a two-stage UCI. For example, the first stage may include information about the number of measurement pairs (e.g., measurement pairs for each cell) or the number of cells with reported measurements, and the measurement pairs are reported in the second stage of the UCI.

[0164] At step 1050 of Figure 10, the source cell 1001 determines which TCI states are activated. For example, the TCI state to be activated may belong to the source cell or to one or more target (or candidate) cells. In one example, the number of cells with an activated TCI state may be limited (e.g., by system specifications and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). In one example, the activated TCI state may be on the source cell and additional target (or candidate) cells. In one example, the activated TCI state may be indicated by MAC CE signaling, where the MAC CE signaling activates the TCI state code point, as mentioned above. In one example, some or all of the activated TCI state code points may belong to the target (or candidate) cell. In one example, a single code point may be activated and therefore applied after a beam application delay.

[0165] At step 1060 of Figure 10, a TCI status code point is indicated to UE 1003. The TCI status code point may be indicated by a DL-related DCI format, where the DL-related DCI format may be one of DCI format 1_1 or DCI format 1_2. The DCI format includes a "Transmission Configuration Indication" field to indicate the code point of the TCI status code point activated by the MAC CE. In one example, the DCI format includes a DL allocation, and in another example, the DCI format does not include a DL allocation. In one example, the indicated TCI status code point belongs to a cell having a PCI different from the PCI of the serving cell, which may be a target (or candidate) cell. In one example, the TCI status code point may be indicated in the MAC CE, as shown in Figure 10.

[0166] In step 1070 of FIG. 10 , the source cell 1001 makes a decision about handover to the target (or candidate) cell 1002 based on the measurement report from the UE 1003 (step 1040). In order to trigger the handover to the target (or candidate) cell 1002, the network may send a dynamic signal (e.g., using MAC CE and / or L1 control) to the UE 1003 to perform the handover. In one example, the signal for handover may be sent to the UE 1003 after the TCI state of the target (or candidate) cell 1002 has been indicated to the UE 1003 or has been applied by the UE 1003.

[0167] At step 1080 of FIG. 10 , the source cell 1001 indicates that the UE 1003 switches from the source cell 1001 to the target (or candidate) cell 1002. The indication of switching from the source cell 1001 to the target (or candidate) cell 1002 may be RRC signaling and / or MACCE signaling and / or L1 control signaling. In one example, switching to the target (or candidate) cell after the cell switching application delay may be as shown in FIG. 11 .

[0168] FIG11 illustrates an example method 1100 of switching to a target (or candidate) cell after a cell switching application delay according to the present disclosure. The embodiment of the switching method shown in FIG11 is for illustration only. Other embodiments of the switching method may be used without departing from the scope of the present disclosure.

[0169] In one example, step 1160 of FIG. 11 may correspond to step 1060 of FIG. 10 , and step 1180 of FIG. 11 may correspond to step 1080 of FIG. 10 .

[0170] Although Figure 11 shows an example of a method 1100 for switching to a target (or candidate) cell after a cell switching application delay, various changes may be made to Figure 16. For example, although shown as a series of steps, the various steps in Figure 16 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0171] In step 1080a of FIG. 10 , information is exchanged between the source cell 1001 and the target (or candidate) cell 1002 to complete the handover at the cell handover time.

[0172] Although Figure 10 shows one example of a switching method 1000 based on TCI status indication, various changes may be made to Figure 10. For example, although shown as a series of steps, the various steps in Figure 10 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0173] In one embodiment, the dynamic switching of the serving cell is initiated based on the UE.

[0174] FIG. 12 shows an example method 1200 for UE-initiated handover according to the present disclosure. The embodiment of the method shown in FIG. 12 is for illustration only. One or more components shown in FIG. 12 may be implemented in a dedicated circuit configured to perform the functions, or one or more components may be implemented by one or more processors that execute instructions to perform the functions. Other embodiments of the handover method may be used without departing from the scope of the present disclosure.

[0175] At step 1210 of FIG. 12 , handover preparation occurs between a source cell 1201 and a target (or candidate) cell 1202. The source cell 1201 may be a serving cell associated with a physical cell identity (PCI). The target (or candidate) cell 1202 may be a second cell associated with a PCI different from the PCI of the serving cell (source cell). There may be one or more target (or candidate) cells, and each target (or candidate) cell may have its own PCI. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI different from the PCI of the other target (or candidate) cells. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI that is the same as the PCI of the other target (or candidate) cells. In one example, if there is more than one target (or candidate) cell, each subset of target (or candidate) cells may have the same PCI as the PCIs of other target (or candidate) cells in the same subset, and other subsets of target (or candidate) cells may have different PCIs.

[0176] In one example, handover preparation may include the exchange of reference signals between cells involved in a potential handover. For example, the reference signal may be a measurement reference signal, where the measurement reference signal is used for measurement reporting from the UE. The measurement signal may be used, for example, to identify a new candidate beam in a serving (e.g., source cell) or target (or candidate) cell. The measurement signal may be used, for example, to determine whether a handover from the source cell to the target (or candidate) cell should be triggered or performed. The measurement metric regarding the measurement reference signal may be L1-reference signal received power (L1-RSRP), a signal to interference and noise ratio (SINR) derived based on the measurement reference signal, a block error rate (BLER), a channel quality indicator (CQI), L3-RSRP (where L3-RSRP is a long-term average (e.g., exponential average) of L1-RSRP), or some other quality metric determined based on the measurement reference signal. The measurement reference signal may include a DL measurement reference signal sent from a network (e.g., a gNB or TRP of a source cell or target (or candidate) cell), where the measurement may be performed in the UE and reported to the network in a measurement report. The measurement reference signal may include an UL measurement reference signal (e.g., SRS) sent by the UE, where the measurement is performed in the network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). In one example, the measurement reference signal is used as a source reference signal.

[0177] In another example, the reference signal may be a source reference signal, where the source reference signal may be used to determine the source of a quasi co-location (QCL) in a TCI state (e.g., a source RS of QCL-TypeA or QCL-TypeB or QCL-TypeC or QCL-TypeD); or determine the source of a spatial relationship (e.g., determining a spatial relationship receive filter or a spatial relationship transmit filter). The source reference signal may include a DL reference signal sent from a network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). The source reference signal may include a UL reference signal (e.g., an SRS) sent by a UE. In one example, the source reference signal may be used as a measurement reference signal.

[0178] In one example, a reference signal (e.g., a measurement reference signal or a source reference signal) may be a synchronization signal block (SSB) (synchronization signal / physical broadcast channel (PBCH) block), where the SSB may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the association may be performed by including the PCI in a configuration of an SSB resource or an information element (IE) including the SSB resource. In another example, the association may be performed by configuration of the SSB resource as part of a configuration of a cell associated with the PCI.

[0179] In another example, the reference signal may be a channel state information reference signal (CSI-RS). The CSI-RS may be, for example, a CSI-RS for mobility (e.g., for handover), or a CSI-RS for beam management, or a CSI-RS for tracking, or a CSI-RS for CSI acquisition. The CSI-RS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of the serving cell (e.g., a target (or candidate) cell). In one example, the association may be through a QCL relationship with an SSB, or a CSI-RS associated with a PCI of a cell. In another example, the association may be performed by including the PCI in the configuration of the CSI-RS resources or in an information element (IE) including the CSI-RS resources. In another example, the association may be performed by configuration of the CSI-RS resources as part of the configuration of the cell associated with the PCI.

[0180] In another example, the reference signal may be a sounding reference signal (SRS), where the SRS is sent by the UE. In one example, the SRS may be an SRS resource for beam management. In another example, the SRS may be an SRS resource for a codebook. In another example, the SRS may be an SRS resource for a non-codebook. In another example, the SRS may be an SRS resource for antenna switching. In another example, the SRS may be an SRS resource for mobility (e.g., for switching). In one example, the SRS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the SRS may not be associated with the PCI of a cell (e.g., the SRS may be sent by a UE and may be received by any cell). In one example, the association may be through a QCL relationship or spatial relationship with an SSB or CSI-RS or SRS associated with the PCI of the cell. In another example, the association may be performed by including the PCI in the configuration of the SRS resource or in an information element (IE) including the SRS resource. In another example, the association may be made through configuration of SRS resources as part of the configuration of the cell associated with the PCI.

[0181] In one example, handover preparation may include exchanging transmission configuration indication (TCI) states between cells involved in a potential handover. For example, the TCI state may include a DL or Joint-TCI state (DLorJoint-TCIState), which includes, for example, one or more of the following: (1) TCI state ID; (2) first QCL information; (3) second QCL information; (4) UL power control ID; (5) path loss reference signal ID; and (6) associated PCI (or, the associated PCI may be included in the QCL information). QCL-Info may include (1) serving cell index; (2) BWP ID; (3) reference signal ID (e.g., CSI-RS resource ID or SSB index); (4) QCL type (e.g., type A, type B, type C, or type D); and (5) PCI index, or, the PCI index may be part of the reference signal ID.

[0182] In another example, the TCI state may include a UL TCI state (UL-TCIState), which includes, for example, one or more of the following: (1) a TCI state ID; (2) a serving cell index; (3) a reference signal ID (e.g., a CSI-RS resource ID or an SSB index or an SRS resource ID); (4) a PCI index, or the PCI index may be part of the reference signal ID; (5) a UL power control ID; and (6) a path loss reference signal ID.

[0183] At step 1220 of FIG. 12 , the network performs RRC (re) configuration to UE 1203. For example, the reconfiguration message may include information related to one or more target (or candidate) cells. For example, the information may include one or more of a reference signal (e.g., a measurement reference signal or a source reference signal as described above) of the target (or candidate) cell or a TCI state of the target (or candidate) cell, as described above.

[0184] At step 1230 of FIG. 12 , UE 1203 responds with RRC (re)configuration complete.

[0185] In step 1240 of FIG. 12 , UE 1203 performs measurements on the configured measurement reference signals of the source cell 1201 and one or more target (or candidate) cells. UE 1203 provides a measurement report to the source cell. The measurement report may include one or more pairs of: (1) a measurement reference signal ID (e.g., a measurement reference signal ID of the source cell or the target (or candidate) cell); (2) a quality metric (e.g., L1-RSRP, SINR, BLER, CQI, L3-RSRP as described above). The measurement report may include measurements from only the source cell, or only the target (or candidate) cell, or from the source cell and the target (or candidate) cell, or from one or more target (or candidate) cells, or from the source cell and one or more target (or candidate) cells. The number of cells in the measurement report may be limited (e.g., by system specifications and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). The number of measurement pairs (e.g., measurement pairs per cell) in a measurement report may be limited (e.g., by system specification and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). The L1 control signaling may be a DL Control Information (DCI) signal. When multiple measurement pairs are reported, differential signaling (reporting) may be used, e.g., the metric for the first pair (e.g., the first pair in the measurement report or the first pair associated with a cell in the measurement report) may be an absolute value. This may be the pair with the best beam metric (e.g., in the measurement report or for each cell in the measurement report). Other pairs in the same report (e.g., across all cells or per cell) may have, e.g., relative metrics of the first pair (e.g., the first pair in the measurement report or the first pair associated with a cell in the measurement report) (or, alternatively, the metrics of the previous pair). The second pair (if any) can have a lower metric than the first pair. dB is the measure of The third pair (if present) may have a lower metric than the first pair (or optionally the second pair) dB is the measure of Being signaled, and so on.

[0186] In one example, the measurement report may be configured periodically. In one example, the measurement report may be configured semi-persistently using a dynamic signal (e.g., via MAC CE or L1 control) to activate or deactivate the transmission of the measurement report. In one example, the measurement report may be triggered aperiodically using a dynamic signal (e.g., via MAC CE or L1 control). In one example, the measurement report may be UE initiated; for example, the UE may send a scheduling request for UL resources to send the measurement report, or the UE may send the measurement report in a configured grant (a grant configured in type 1 or type 2) resource, or the UE may send the measurement report using a random access procedure (e.g., a type 1 random access procedure or a type 2 random access procedure).

[0187] In one example, the measurement report may be reported in uplink control information (UCI) in a physical uplink control channel (PUCCH). In one example, if the PUCCH overlaps with a physical uplink shared channel (PUSCH), the PUCCH may not be sent and the UCI is multiplexed into the PUSCH. In one example, the measurement report may be reported in the UCI in the PUSCH. In one example, the measurement report may be reported in a MAC CE. In one example, the measurement report may be reported in a single-stage UCI. In another example, the measurement report may be reported in a two-stage UCI. For example, the first stage may include information about the number of measurement pairs (e.g., measurement pairs for each cell) or the number of cells with reported measurements, and the measurement pairs are reported in the second stage of the UCI.

[0188] At step 1250 of Figure 12, the source cell 1201 determines which TCI states are activated. For example, the TCI state to be activated may belong to the source cell or to one or more target (or candidate) cells. In one example, the number of cells with an activated TCI state may be limited (e.g., by system specifications and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). In one example, the activated TCI state may be on the source cell and additional target (or candidate) cells. In one example, the activated TCI state may be indicated by MAC CE signaling, where the MAC CE signaling activates the TCI state code point, as mentioned above. In one example, some or all of the activated TCI state code points may belong to the target (or candidate) cell. In one example, a single code point may be activated and therefore applied after a beam application delay.

[0189] At step 1260 of Figure 12, UE 1203 may initiate a handover, or may make a decision about the handover based on measurements performed at the UE using measurement reference signals from the source cell 1201 and one or more target (or candidate) cells. In one example, the UE initiating the handover may be event triggered. In one example, the UE initiating the handover may not be event based. In one example, if one or more activated TCI state code points belong to the target (or candidate) cell, the UE may make a decision to perform or trigger or initiate a handover to the target (or candidate) cell. In one example, if the UE has been indicated a TCI state and the TCI state is associated with the target (or candidate) cell, the UE may make a decision to perform or trigger or initiate a handover to the target (or candidate) cell. In one example, the target (or candidate) cell may be a cell associated with the most recently indicated TCI state. In one example, the target (or candidate) cell may be a cell associated with an activated TCI state (e.g., in addition to a serving cell). In one example, the target (or candidate) cell may be a cell associated with a most recently applied TCI state. The TCI state code point may be indicated by a DL-related DCI format, wherein the DL-related DCI format may be one of DCI format 1_1 or DCI format 1_2. The DCI format may include a "Transmission Configuration Indication" field to indicate the code point of the TCI state code point activated by the MAC CE. In one example, the DCI format may include a DL allocation. In another example, the DCI format may not include a DL allocation.

[0190] In step 1270 of FIG. 12 , in order to request or perform or trigger or initiate a handover, the UE 1203 provides a message to the network (which is shown as a measurement report in FIG. 12 ). In one example, the message may be a measurement report, and the measurement report may include a flag or information element (IE) indicating that the UE is requesting or is triggering or is initiating a handover to a target (or candidate) cell. The IE may include a target (or candidate) cell index, or the target (or candidate) cell may be implicitly determined (e.g., a cell with an indicated TCI state or a cell with an activated TCI state (other than the source cell)).

[0191] In another example, the message may be a measurement report, and the measurement report may include only measurement pairs associated with the target (or candidate) cell. The measurement report may include a flag indicating that the UE is requesting or is triggering or is initiating a handover to the target (or candidate) cell. Alternatively, there may be no flag, and the handover to the target (or candidate) cell may be determined implicitly.

[0192] In another example, the message may be a measurement report, and the measurement report may include measurement pairs associated with multiple cells. The first measurement pair (i.e., the measurement pair with the best metric) may be associated with the target (or candidate) cell. The measurement report may include a flag indicating that the UE is requesting or is triggering or is initiating a handover to the target (or candidate) cell. Alternatively, the flag may not be present, and the handover to the target (or candidate) cell may be implicitly determined.

[0193] In another example, the message may be an information element including a target (or candidate) cell to which the UE is requesting or is triggering or initiating a handover.

[0194] In step 1270 of Figure 12, the message provided by UE 1203 to request or perform or trigger or initiate handover may be sent to source cell 1201 (as shown in Figure 12) or target (or candidate) cell 1202. The cell to which the message is sent may be determined by the TCI state most recently indicated to the UE.

[0195] In one example, the message provided by UE 1203 to request or perform or trigger or initiate a handover may be periodically configured. In one example, the message may be semi-persistently configured, using a dynamic signal (e.g., controlled by MAC CE or L1) to activate or deactivate the transmission of the message. In one example, the message may be triggered aperiodically using a dynamic signal (e.g., controlled by MAC CE or L1). In one example, the message may be UE-initiated; for example, the UE may send a scheduling request for UL resources to send the message, or the UE may send the message in a configured grant (a grant configured in type 1 or type 2) resource, or the UE may send the message using a random access procedure (e.g., a type 1 random access procedure or a type 2 random access procedure).

[0196] In one example, the message provided by UE 1203 to request or perform or trigger or initiate a handover may be reported in uplink control information (UCI) in a physical uplink control channel (PUCCH). In one example, if the PUCCH overlaps with a physical uplink shared channel (PUSCH), the PUCCH may not be sent and the UCI may be multiplexed into the PUSCH. In one example, the message provided by the UE to request or perform or trigger or initiate a handover may be reported in the UCI in the PUSCH. In one example, the message provided by the UE to request or perform or trigger or initiate a handover may be reported in a MAC CE. In one example, the message provided by the UE to request or perform or trigger or initiate a handover may be reported in a MAC CE. In one example, the message may be reported in a single-stage UCI. In another example, the message may be reported in a two-stage UCI.

[0197] In one example, a message from the UE may trigger a handover to a target (or candidate) cell after a cell switching time (delay), as shown in FIG. 13 .

[0198] FIG13 shows an example method 1300 for switching to a target (or candidate) cell after a cell switching time according to the present disclosure. The embodiment of the switching method shown in FIG13 is for illustration only. Other embodiments of the switching method may be used without departing from the scope of the present disclosure.

[0199] In one example (Example 2 in Figure 13), the cell switching time (delay) may come from a message from the UE indicating or requesting or triggering or initiating a switch (this may be on the PUCCH or PUSCH (UCI or MAC CE) as previously described). The cell switching time may come from the end of the message (Example 2 in Figure 13) or from the beginning of the message. In another example (Example 1 in Figure 13), the cell switching time (delay) may come from an acknowledgment of a UE message indicating or requesting or triggering or initiating a switch. The cell switching time may come from the end of an ACK message (Example 1 in Figure 13) or from the beginning of an ACK message. In one example, the ACK message may be a DCI format on a PDCCH sent by the network in response to a message from the UE. In another example, the ACK message may be a DL transmission (e.g., PDCCH+PDSCH or MAC CE) sent by the network in response to a message from the UE.

[0200] In one example, if the UE requests / triggers / initiates / indicates a handover to the network and the most recently indicated beam is not on the target (or candidate) cell (e.g., the most recently indicated beam is on the source cell), the network may apply the beam on the target (or candidate) cell before or simultaneously with the cell handover.

[0201] In one example, the network may determine the TCI state of the target (or candidate) cell based on the measurement report and indicate the TCI state to the UE (e.g., as described in FIG. 8). Cell switching may occur when the TCI state of the target (or candidate) cell is applied (e.g., as shown in FIG. 9).

[0202] In one example, the TCI state of the target (or candidate) cell may be determined by the UE and indicated in a message from the UE requesting / triggering / initiating / indicating handover. The TCI state indicated by the UE may be applied at the time of cell handover, for example, as shown in FIG. 13.

[0203] In one example, the TCI state of the target (or candidate) cell may be determined by the UE in a measurement report. The TCI state associated with the strongest measurement pair from the target (or candidate) cell may be used. In one example, the TCI state based on, for example, the strongest pair in the measurement report may be indicated to the UE, and the cell switching time may follow Figures 8 and 9. In one example, the TCI state may be implicitly determined based on the strongest pair associated with the target (or candidate) cell in the measurement report from the UE without further signaling from the network, and the corresponding TCI state may be applied at the cell switching time, for example, as shown in Figure 13.

[0204] Although Figure 13 shows an example of a method 1300 for switching to a target (or candidate) cell after a cell switching time, various changes may be made to Figure 13. For example, although shown as a series of steps, the various steps in Figure 13 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0205] At step 1270a of FIG. 12 , information is exchanged between the source cell 1201 and the target (or candidate) cell 1202 to complete the handover at the cell switching time.

[0206] Although Figure 12 shows an example of a method 1200 based on UE-initiated handover, various changes may be made to Figure 12. For example, although shown as a series of steps, the various steps in Figure 12 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0207] In one embodiment, the dynamic switching of the serving cell is initiated based on the UE.

[0208] FIG. 14 shows an example method 1400 for UE-initiated handover according to the present disclosure. The embodiment of the method shown in FIG. 14 is for illustration only. One or more components shown in FIG. 14 may be implemented in a dedicated circuit configured to perform the functions, or one or more components may be implemented by one or more processors that execute instructions to perform the functions. Other embodiments of the handover method may be used without departing from the scope of the present disclosure.

[0209] At step 1410 of FIG. 14 , handover preparation occurs between a source cell 1401 and a target (or candidate) cell 1402. The source cell 1401 may be a serving cell associated with a physical cell identity (PCI). The target (or candidate) cell 1402 may be a second cell associated with a PCI different from the PCI of the serving cell (source cell). There may be one or more target (or candidate) cells, and each target (or candidate) cell may have its own PCI. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI different from the PCI of the other target (or candidate) cells. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI that is the same as the PCI of the other target (or candidate) cells. In one example, if there is more than one target (or candidate) cell, each subset of target (or candidate) cells may have the same PCI as the PCIs of other target (or candidate) cells in the same subset, while other subsets of target (or candidate) cells may have different PCIs.

[0210] In one example, handover preparation may include the exchange of reference signals between cells involved in a potential handover. For example, the reference signal may be a measurement reference signal, where the measurement reference signal is used for measurement reporting from the UE. The measurement signal may be used, for example, to identify a new candidate beam in a serving (e.g., source cell) or target (or candidate) cell. The measurement signal may be used, for example, to determine whether a handover from the source cell to the target (or candidate) cell should be triggered or performed. The measurement metric regarding the measurement reference signal may be L1-reference signal received power (L1-RSRP), a signal to interference and noise ratio (SINR) derived based on the measurement reference signal, a block error rate (BLER), a channel quality indicator (CQI), L3-RSRP (where L3-RSRP is a long-term average (e.g., exponential average) of L1-RSRP), or some other quality metric determined based on the measurement reference signal. The measurement reference signal may include a DL measurement reference signal sent from a network (e.g., a gNB or TRP of a source cell or target (or candidate) cell), where the measurement may be performed in the UE and reported to the network in a measurement report. The measurement reference signal may include an UL measurement reference signal (e.g., SRS) sent by the UE, where the measurement is performed in the network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). In one example, the measurement reference signal is used as a source reference signal.

[0211] In another example, the reference signal may be a source reference signal, where the source reference signal may be used to determine the source of a quasi co-location (QCL) in a TCI state (e.g., a source RS of QCL-TypeA or QCL-TypeB or QCL-TypeC or QCL-TypeD); or determine the source of a spatial relationship (e.g., determining a spatial relationship receive filter or a spatial relationship transmit filter). The source reference signal may include a DL reference signal sent from a network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). The source reference signal may include a UL reference signal (e.g., an SRS) sent by a UE. In one example, the source reference signal is used as a measurement reference signal.

[0212] In one example, a reference signal (e.g., a measurement reference signal or a source reference signal) may be a synchronization signal block (SSB) (synchronization signal / physical broadcast channel (PBCH) block), where the SSB may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the association may be performed by including the PCI in a configuration of an SSB resource or an information element (IE) including the SSB resource. In another example, the association may be performed by configuration of the SSB resource as part of a configuration of a cell associated with the PCI.

[0213] In another example, the reference signal may be a channel state information reference signal (CSI-RS). The CSI-RS may be, for example, a CSI-RS for mobility (e.g., for handover), or a CSI-RS for beam management, or a CSI-RS for tracking, or a CSI-RS for CSI acquisition. The CSI-RS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of the serving cell (e.g., a target (or candidate) cell). In one example, the association may be through a QCL relationship with an SSB, or a CSI-RS associated with a PCI of a cell. In another example, the association may be performed by including the PCI in the configuration of the CSI-RS resources or in an information element (IE) including the CSI-RS resources. In another example, the association may be performed by configuration of the CSI-RS resources as part of the configuration of the cell associated with the PCI.

[0214] In another example, the reference signal may be a sounding reference signal (SRS), where the SRS is sent by the UE. In one example, the SRS may be an SRS resource for beam management. In another example, the SRS may be an SRS resource for a codebook. In another example, the SRS may be an SRS resource for a non-codebook. In another example, the SRS may be an SRS resource for antenna switching. In another example, the SRS may be an SRS resource for mobility (e.g., for switching). In one example, the SRS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the SRS is not associated with the PCI of the cell (e.g., the SRS may be sent by the UE and may be received by any cell). In one example, the association may be through a QCL relationship or spatial relationship with an SSB or CSI-RS or SRS associated with the PCI of the cell. In another example, the association may be performed by including the PCI in the configuration of the SRS resource or in an information element (IE) including the SRS resource. In another example, the association may be made through configuration of SRS resources as part of the configuration of the cell associated with the PCI.

[0215] In one example, handover preparation may include exchanging transmission configuration indication (TCI) states between cells involved in a potential handover. For example, the TCI state may include a DL or Joint-TCI state (DLorJoint-TCIState), which includes, for example, one or more of the following: (1) TCI state ID; (2) first QCL information; (3) second QCL information; (4) UL power control ID; (5) path loss reference signal ID; and (6) associated PCI (or, the associated PCI may be included in the QCL information). QCL-Info may include (1) serving cell index; (2) BWP ID; (3) reference signal ID (e.g., CSI-RS resource ID or SSB index); (4) QCL type (e.g., type A, type B, type C, or type D); and (5) PCI index, or, the PCI index may be part of the reference signal ID.

[0216] In another example, the TCI state may include a UL TCI state (UL-TCIState), which includes, for example, one or more of the following: (1) a TCI state ID; (2) a serving cell index; (3) a reference signal ID (e.g., a CSI-RS resource ID or an SSB index or an SRS resource ID); (4) a PCI index, or the PCI index may be part of the reference signal ID; (5) a UL power control ID; and (6) a path loss reference signal ID.

[0217] In one example, handover preparation may include association of a measurement reference signal of a target (or candidate) cell with a scheduling request resource of the target (or candidate) cell. For example, RS0 may be associated with SR0, and RS1 may be associated with SR1. When the UE determines RS0 as the preferred measurement RS on the target (or candidate) cell, it may send a scheduling request in the associated SR resource.

[0218] At step 1420 of FIG. 14 , the network performs RRC (re)configuration to UE 1403. For example, the reconfiguration message may include information related to one or more target (or candidate) cells. In one example, the information may include a reference signal of the target (or candidate) cell; for example, a measurement reference signal or a source reference signal as described above. In another example, the information may include a TCI state of the target (or candidate) cell as mentioned above. In another example, the information may include an association of a measurement RS with a scheduling request resource of the target (or candidate) cell as described above.

[0219] At step 1430 of FIG. 14 , UE 1403 responds with RRC (re)configuration complete.

[0220] At step 1440 of FIG. 14 , UE 1403 may initiate a handover, or may make a decision about the handover based on measurements performed at the UE using measurement reference signals from a source cell and one or more target (or candidate) cells. In one example, the UE initiating a handover may be event triggered. In one example, the UE initiating a handover may not be event based.

[0221] At step 1450 of Figure 14, UE 1403 sends a scheduling request (SR) to the target (or candidate) cell 1402, the SR being associated with the preferred measurement RS of the target (or candidate) cell. The resource of the SR may be an implicit indication of the preferred beam to be used from the target (or candidate) cell.

[0222] At step 1460 of Figure 14, the network may optionally indicate the TCI state based on the preferred beam associated with the SR from the UE. The indication may come from a target (or candidate) cell that uses a beam indicated for DCI use following the preferred beam of the SR resource. Alternatively, the indication may come from a source cell using the most recently indicated TCI state. In one example, the indication of the TCI state may be via a MAC CE from the target cell. In one example, the indication of the TCI state may be via a MAC CE from the source cell. The network may optionally not indicate the TCI state. Alternatively, the TCI state may be implicitly determined as the TCI state associated with the SR resource used by the UE. The corresponding beam application time may be after a processing delay from the end (or alternatively the start) of the SR resource. At step 1460b, the network may send an uplink grant for the UE to report a beam measurement report. In one example, the UL grant may be in a MAC CE (e.g., from a source cell or a target cell). In one example, the UL grant may be in the same MAC CE as the MAC CE used to indicate the TCI state.

[0223] At step 1470 of FIG. 14 , a measurement report is sent from UE 1403 to the network, for example using resources provided by the UL grant of step 1460b. In one example, the UE may send the measurement report and a confirmed handover from the source cell to the target (or candidate) cell may occur without additional signaling. In another example, the network may signal the UE to handover the target (or candidate) cell, as shown in FIGS. 10 and 11 .

[0224] Although Figure 14 shows an example of a method 1400 based on UE-initiated handover, various changes may be made to Figure 14. For example, although shown as a series of steps, the various steps in Figure 14 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0225] In one embodiment, the dynamic switching of the serving cell is initiated based on the UE.

[0226] FIG. 15 shows an example method 1500 for UE-initiated handover. According to the present disclosure. The embodiment of the method shown in FIG. 15 is for illustration only. One or more of the components shown in FIG. 15 may be implemented in a dedicated circuit configured to perform the functions, or one or more of the components may be implemented by one or more processors that execute instructions to perform the functions. Other embodiments of the handover method may be used without departing from the scope of the present disclosure.

[0227] In step 1510 of FIG. 15 , handover preparation occurs between a source cell 1501 and a target (or candidate) cell 1502. The source cell 1502 may be a serving cell associated with a physical cell identity (PCI). The target (or candidate) cell 1502 may be a second cell associated with a PCI different from the PCI of the serving cell 1501 (source cell). There may be one or more target (or candidate) cells, and each target (or candidate) cell may have its own PCI. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI different from the PCI of the other target (or candidate) cells. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI that is the same as the PCI of the other target (or candidate) cells. In one example, if there is more than one target (or candidate) cell, each subset of target (or candidate) cells may have the same PCI as the PCIs of other target (or candidate) cells in the same subset, while other subsets of target (or candidate) cells may have different PCIs.

[0228] In one example, handover preparation may include the exchange of reference signals between cells involved in a potential handover. For example, the reference signal may be a measurement reference signal, where the measurement reference signal is used for measurement reporting from the UE. The measurement signal may be used, for example, to identify a new candidate beam in a serving (e.g., source cell) or target (or candidate) cell. The measurement signal may be used, for example, to determine whether a handover from the source cell to the target (or candidate) cell should be triggered or performed. The measurement metric regarding the measurement reference signal may be L1-reference signal received power (L1-RSRP), a signal to interference and noise ratio (SINR) derived based on the measurement reference signal, a block error rate (BLER), a channel quality indicator (CQI), L3-RSRP (where L3-RSRP is a long-term average (e.g., exponential average) of L1-RSRP), or some other quality metric determined based on the measurement reference signal. The measurement reference signal may include a DL measurement reference signal sent from a network (e.g., a gNB or TRP of a source cell or target (or candidate) cell), where the measurement may be performed in the UE and reported to the network in a measurement report. The measurement reference signal may include an UL measurement reference signal (e.g., SRS) sent by the UE, where the measurement is performed in the network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). In one example, the measurement reference signal may be used as a source reference signal.

[0229] In another example, the reference signal may be a source reference signal, where the source reference signal may be used to determine the source of quasi co-location (QCL) in the TCI state (e.g., the source RS of QCL-TypeA or QCL-TypeB or QCL-TypeC or QCL-TypeD); or determine the source of the spatial relationship (e.g., determine the spatial relationship receiving filter or the spatial relationship transmitting filter). The source reference signal may include a DL reference signal sent from the network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). The source reference signal may include a UL reference signal (e.g., SRS) sent by the UE.

[0230] The reference signal (e.g., a measurement reference signal or a source reference signal) may be a synchronization signal block (SSB) (synchronization signal / physical broadcast channel (PBCH) block), wherein the SSB may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the association may be performed by including the PCI in the configuration of the SSB resource or in an information element (IE) including the SSB resource. In another example, the association may be performed by configuration of the SSB resource as part of the configuration of the cell associated with the PCI.

[0231] In another example, the reference signal may be a channel state information reference signal (CSI-RS). The CSI-RS may be, for example, a CSI-RS for mobility (e.g., for handover), or a CSI-RS for beam management, or a CSI-RS for tracking, or a CSI-RS for CSI acquisition. The CSI-RS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of the serving cell (e.g., a target (or candidate) cell). In one example, the association may be through a QCL relationship with an SSB, or a CSI-RS associated with a PCI of a cell. In another example, the association may be performed by including the PCI in the configuration of the CSI-RS resources or in an information element (IE) including the CSI-RS resources. In another example, the association may be performed by configuration of the CSI-RS resources as part of the configuration of the cell associated with the PCI.

[0232] In another example, the reference signal may be a sounding reference signal (SRS), where the SRS is sent by the UE. In one example, the SRS may be an SRS resource for beam management. In another example, the SRS may be an SRS resource for a codebook. In another example, the SRS may be an SRS resource for a non-codebook. In another example, the SRS may be an SRS resource for antenna switching. In another example, the SRS may be an SRS resource for mobility (e.g., for switching). In one example, the SRS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the SRS may not be associated with the PCI of a cell (e.g., the SRS may be sent by a UE and may be received by any cell). In one example, the association may be through a QCL relationship or spatial relationship with an SSB or CSI-RS or SRS associated with the PCI of the cell. In another example, the association may be performed by including the PCI in the configuration of the SRS resource or in an information element (IE) including the SRS resource. In another example, the association may be made through configuration of SRS resources as part of the configuration of the cell associated with the PCI.

[0233] In one example, handover preparation may include exchanging transmission configuration indication (TCI) states between cells involved in a potential handover. For example, the TCI state may include a DL or Joint-TCI state (DLorJoint-TCIState), which includes, for example, one or more of the following: (1) TCI state ID; (2) first QCL information; (3) second QCL information; (4) UL power control ID; (5) path loss reference signal ID; and (6) associated PCI (or, the associated PCI may be included in the QCL information). QCL-Info may include (1) serving cell index; (2) BWP ID; (3) reference signal ID (e.g., CSI-RS resource ID or SSB index); (4) QCL type (e.g., type A, type B, type C, or type D); and (5) PCI index, or, the PCI index may be part of the reference signal ID.

[0234] In another example, the TCI state may include a UL TCI state (UL-TCIState), which includes, for example, one or more of the following: (1) a TCI state ID; (2) a serving cell index; (3) a reference signal ID (e.g., a CSI-RS resource ID or an SSB index or an SRS resource ID); (4) a PCI index, or the PCI index may be part of the reference signal ID; (5) a UL power control ID; and (6) a path loss reference signal ID.

[0235] In one example, handover preparation may include association of a measurement reference signal of a target (or candidate) cell with a dedicated preamble resource of the target (or candidate) cell. For example, RS0 may be associated with preamble 0, and RS1 may be associated with preamble 1. When the UE determines RS0 as the preferred measurement RS on the target (or candidate) cell, it may initiate a random access procedure using the associated preamble.

[0236] At step 1520 of Figure 15, the network performs RRC (re) configuration towards UE 1503. For example, the reconfiguration message may include information related to one or more target (or candidate) cells. In one example, the information may include a reference signal of the target (or candidate) cell; for example, a measurement reference signal or a source reference signal as described above. In another example, the information may include a TCI state of the target (or candidate) cell as mentioned above. In another example, the information may include an association of the measurement RS with the preamble resources of the target (or candidate) cell as described above.

[0237] At step 1530 of FIG. 15 , UE 1503 responds with RRC (re)configuration complete.

[0238] At step 1540 of Figure 15, UE 1503 may initiate a handover, or may make a decision about the handover based on measurements performed at the UE using measurement reference signals from a source cell and one or more target (or candidate) cells. In one example, the UE initiating a handover may be event triggered. In one example, the UE initiating a handover may not be event based.

[0239] At step 1540 of Figure 15, UE 1503 triggers a random access procedure. In one example, the triggered random access procedure may be a type 1 random access procedure (e.g., 4-step RACH). In another example, the triggered random access procedure may be a type 2 random access procedure (e.g., 2-step RACH). In another example, the random access procedure may be a contention-based random access procedure. In another example, the random access procedure may be a contention-free random access procedure, for example, the UE may use a dedicated preamble, wherein the preamble may be associated with a measurement RS as described above. The UE may send a preamble to a target (or candidate) cell, the preamble being associated with a preferred measurement RS of the target (or candidate) cell. The preamble may be an implicit indication of a preferred beam to be used from the target (or candidate) cell. In one example, during the RACH procedure, the UE may communicate a beam measurement report.

[0240] After the random access procedure, the handover procedure from the source cell 1501 to the target (or candidate) cell 1503 is completed. In one example, after the random access procedure is completed, the handover from the source cell to the target (or candidate) cell may occur without additional signaling. In another example, the network may signal the handover target (or candidate) cell to the UE, as shown in Figures 10 and 11.

[0241] Although Figure 15 shows an example of a method 1500 based on UE-initiated handover, various changes may be made to Figure 15. For example, although shown as a series of steps, the various steps in Figure 15 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0242] In one embodiment, the dynamic switching of the serving cell is initiated based on the UE.

[0243] FIG. 16 shows an example method 1600 for UE-initiated handover according to the present disclosure. The embodiment of the method shown in FIG. 16 is for illustration only. One or more of the components shown in FIG. 16 may be implemented in a dedicated circuit configured to perform the functions, or one or more of the components may be implemented by one or more processors that execute instructions to perform the functions. Other embodiments of the handover method may be used without departing from the scope of the present disclosure.

[0244] At step 1610 of Figure 16, handover preparation occurs between the source cell 1601 and the target (or candidate) cell 1602. The source cell 1601 may be a serving cell associated with a physical cell identity (PCI). The target (or candidate) cell 1602 may be a second cell associated with a PCI different from the PCI of the serving cell 1601 (source cell). There may be one or more target (or candidate) cells, and each target (or candidate) cell may have its own PCI. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI different from the PCI of the other target (or candidate) cells. In one example, if there are more than one target (or candidate) cell, each target (or candidate) cell may have a PCI that is the same as the PCI of the other target (or candidate) cells. In one example, if there is more than one target (or candidate) cell, each subset of target (or candidate) cells may have the same PCI as the PCIs of other target (or candidate) cells in the same subset, while other subsets of target (or candidate) cells may have different PCIs.

[0245] In one example, handover preparation may include the exchange of reference signals between cells involved in a potential handover. For example, the reference signal may be a measurement reference signal, where the measurement reference signal is used for measurement reporting from the UE. The measurement signal may be used, for example, to identify a new candidate beam in a serving (e.g., source cell) or target (or candidate) cell. The measurement signal may be used, for example, to determine whether a handover from the source cell to the target (or candidate) cell should be triggered or performed. The measurement metric regarding the measurement reference signal may be L1-reference signal received power (L1-RSRP), a signal to interference and noise ratio (SINR) derived based on the measurement reference signal, a block error rate (BLER), a channel quality indicator (CQI), L3-RSRP (where L3-RSRP is a long-term average (e.g., exponential average) of L1-RSRP), or some other quality metric determined based on the measurement reference signal. The measurement reference signal may include a DL measurement reference signal sent from a network (e.g., a gNB or TRP of a source cell or target (or candidate) cell), where the measurement may be performed in the UE and reported to the network in a measurement report. The measurement reference signal may include an UL measurement reference signal (e.g., SRS) sent by the UE, where the measurement is performed in the network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). In one example, the measurement reference signal may be used as a source reference signal.

[0246] In another example, the reference signal may be a source reference signal, where the source reference signal may be used to determine the source of a quasi co-location (QCL) in a TCI state (e.g., a source RS of QCL-TypeA or QCL-TypeB or QCL-TypeC or QCL-TypeD); or determine the source of a spatial relationship (e.g., determining a spatial relationship receive filter or a spatial relationship transmit filter). The source reference signal may include a DL reference signal sent from a network (e.g., a gNB or TRP of a source cell or a target (or candidate) cell). The source reference signal may include a UL reference signal (e.g., an SRS) sent by a UE. In one example, the source reference signal may be used as a measurement reference signal.

[0247] In one example, a reference signal (e.g., a measurement reference signal or a source reference signal) may be a synchronization signal block (SSB) (synchronization signal / physical broadcast channel (PBCH) block), where the SSB may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the association may be performed by including the PCI in a configuration of an SSB resource or an information element (IE) including the SSB resource. In another example, the association may be performed by configuration of the SSB resource as part of a configuration of a cell associated with the PCI.

[0248] In another example, the reference signal may be a channel state information reference signal (CSI-RS). The CSI-RS may be, for example, a CSI-RS for mobility (e.g., for handover), or a CSI-RS for beam management, or a CSI-RS for tracking, or a CSI-RS for CSI acquisition. The CSI-RS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of the serving cell (e.g., a target (or candidate) cell). In one example, the association may be through a QCL relationship with an SSB, or a CSI-RS associated with a PCI of a cell. In another example, the association may be performed by including the PCI in the configuration of the CSI-RS resources or in an information element (IE) including the CSI-RS resources. In another example, the association may be performed by configuration of the CSI-RS resources as part of the configuration of the cell associated with the PCI.

[0249] In another example, the reference signal may be a sounding reference signal (SRS), where the SRS is sent by the UE. In one example, the SRS may be an SRS resource for beam management. In another example, the SRS may be an SRS resource for a codebook. In another example, the SRS may be an SRS resource for a non-codebook. In another example, the SRS may be an SRS resource for antenna switching. In another example, the SRS may be an SRS resource for mobility (e.g., for switching). In one example, the SRS may be associated with a PCI of a serving cell (e.g., a source cell) or a PCI of a cell different from the PCI of a serving cell (e.g., a target (or candidate) cell). In one example, the SRS is not associated with the PCI of the cell (e.g., the SRS may be sent by the UE and may be received by any cell). In one example, the association may be through a QCL relationship or spatial relationship with an SSB or CSI-RS or SRS associated with the PCI of the cell. In another example, the association may be performed by including the PCI in the configuration of the SRS resource or in an information element (IE) including the SRS resource. In another example, the association may be made through configuration of SRS resources as part of the configuration of the cell associated with the PCI.

[0250] In one example, handover preparation may include exchanging transmission configuration indication (TCI) states between cells involved in a potential handover. For example, the TCI state may include a DL or Joint-TCI state (DLorJoint-TCIState), which includes, for example, one or more of the following: (1) TCI state ID; (2) first QCL information; (3) second QCL information; (4) UL power control ID; (5) path loss reference signal ID; and (6) associated PCI (or, the associated PCI may be included in the QCL information). QCL-Info may include (1) serving cell index; (2) BWP ID; (3) reference signal ID (e.g., CSI-RS resource ID or SSB index); (4) QCL type (e.g., type A, type B, type C, or type D); and (5) PCI index, or, the PCI index may be part of the reference signal ID.

[0251] In another example, the TCI state may include a UL TCI state (UL-TCIState), which includes, for example, one or more of the following: (1) a TCI state ID; (2) a serving cell index; (3) a reference signal ID (e.g., a CSI-RS resource ID or an SSB index or an SRS resource ID); (4) a PCI index, or the PCI index may be part of the reference signal ID; (5) a UL power control ID; and (6) a path loss reference signal ID.

[0252] At step 1620 of FIG. 16 , the network performs RRC (re) configuration to UE 1603. For example, the reconfiguration message may include information related to one or more target (or candidate) cells. For example, the information may include one or more of a reference signal (e.g., a measurement reference signal or a source reference signal as described above) of the target (or candidate) cell or a TCI state of the target (or candidate) cell, as described above.

[0253] At step 1630 of FIG. 16 , UE 1603 responds with RRC (re)configuration complete.

[0254] In step 1640 of FIG. 16 , UE 1603 performs measurements on the configured measurement reference signals of the source cell and one or more target (or candidate) cells. UE 1620 may provide a measurement report to the source cell. The measurement report may include one or more pairs of: (1) a measurement reference signal ID (e.g., a measurement reference signal ID of the source cell or the target (or candidate) cell); (2) a quality metric (e.g., L1-RSRP, SINR, BLER, CQI, L3-RSRP as described above). The measurement report may include measurements from only the source cell, or only the target (or candidate) cell, or from the source cell and the target (or candidate) cell, or from one or more target (or candidate) cells, or from the source cell and one or more target (or candidate) cells. The number of cells in the measurement report may be limited (e.g., by system specification and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). The number of measurement pairs (e.g., measurement pairs per cell) in a measurement report may be limited (e.g., by system specification and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). The L1 control signaling may be a DL Control Information (DCI) signal. When multiple measurement pairs are reported, differential signaling (reporting) may be used, e.g., the metric of the first pair (e.g., the first pair in the measurement report or the first pair associated with a cell in the measurement report) is an absolute value, then this is the pair with the best beam metric (e.g., in the measurement report or for each cell in the measurement report), and the other pairs in the same report (e.g., across all cells or for each cell) have, for example, a metric relative to the first pair (e.g., the first pair in the measurement report or the first pair associated with a cell in the measurement report) (or optionally, the metric of the previous pair). The second pair (if any) can have a lower metric than the first pair. dB is the measure of The third pair (if present) may have a lower metric than the first pair (or optionally the second pair) dB is the measure of Being signaled, and so on.

[0255] In one example, the measurement report may be configured periodically. In one example, the measurement report may be configured semi-persistently using a dynamic signal (e.g., via MAC CE or L1 control) to activate or deactivate the transmission of the measurement report. In one example, the measurement report may be triggered aperiodically using a dynamic signal (e.g., via MAC CE or L1 control). In one example, the measurement report may be UE initiated; for example, the UE may send a scheduling request for UL resources to send the measurement report, or the UE may send the measurement report in a configured grant (a grant configured in type 1 or type 2) resource, or the UE may send the measurement report using a random access procedure (e.g., a type 1 random access procedure or a type 2 random access procedure).

[0256] In one example, the measurement report may be reported in uplink control information (UCI) in a physical uplink control channel (PUCCH). In one example, if the PUCCH overlaps with a physical uplink shared channel (PUSCH), the PUCCH may not be sent and the UCI is multiplexed into the PUSCH. In one example, the measurement report may be reported in the UCI in the PUSCH. In one example, the measurement report may be reported in a MAC CE. In one example, the measurement report may be reported in a single-stage UCI. In another example, the measurement report may be reported in a two-stage UCI. For example, the first stage may include information about the number of measurement pairs (e.g., measurement pairs for each cell) or the number of cells with reported measurements, and the measurement pairs may be reported in the second stage of the UCI.

[0257] At step 1650 of Figure 16, the source cell 1601 may determine which TCI states to activate. For example, the TCI state to be activated may belong to the source cell or to one or more target (or candidate) cells. In one example, the number of cells with an activated TCI state may be limited (e.g., by system specifications and / or by RRC configuration and / or MAC CE signaling and / or L1 control signaling). In one example, the activated TCI state may be on the source cell and additional target (or candidate) cells. In one example, the activated TCI state is indicated by MAC CE signaling, where the MAC CE signaling activates the TCI state code point as described above. In one example, some or all of the activated TCI state code points belong to the target (or candidate) cell. In one example, a single code point is activated and is therefore applied after a beam application delay.

[0258] At step 1660 of Figure 16, a TCI status code point is indicated to UE 1603. The TCI status code point may be indicated by a DL-related DCI format, where the DL-related DCI format may be one of DCI format 1_1 or DCI format 1_2. The DCI format may include a "transmission configuration indication" field to indicate the code point of the TCI status code point activated by the MAC CE. In one example, the DCI format may include a DL allocation. In another example, the DCI format may not include a DL allocation. In one example, the indicated TCI status code point may belong to a cell having a PCI different from the PCI of the serving cell. This may be a target (or candidate) cell. In one example, the TCI status code point may be indicated in the MAC CE, as shown in Figure 16. In one example, multiple TCI status code points may be indicated.

[0259] In one example, as shown in FIG. 16 , two TCI states may be indicated to the UE 1603, one for the source cell and one for the target (or candidate) cell (M=2, N=2). The network may determine the TCI state of the target (or candidate) cell based on the measurement report from the UE. M is the number of DL TCI states indicated to the UE, and N is the number of UL TCI states indicated to the UE. The UE selects one of the UL or joint TCI states for UL transmission of the measurement report to the network (source cell or target (or candidate) cell) (step 8 of FIG. 16 ). If the measurement report is sent to the target (or candidate) cell, the TCI state of the target (or candidate) cell may be used to perform subsequent DL reception and UL transmission. The handover may be determined by the UE (step 7 of FIG. 16 ) (sending the measurement report to the target), or by the target (or candidate) cell, and an indicator (DCI or MAC CE) is sent from the target (or candidate) cell to the UE for the handover.

[0260] In one example, the UE may be indicated two UL TCI states, one for the source cell and one for the target (or candidate) cell (M=1, N=2). M is the number of DL TCI states indicated to the UE, and N is the number of UL TCI states indicated to the UE. The UE selects one of the UL TCI states for UL transmission of measurement reports to the network (source cell or target (or candidate) cell). If the measurement report is sent to the target (or candidate) cell, the target (or candidate) cell may decide whether to perform a handover. The handover command (MAC CE or DCI) to the UE is sent from the source cell. The handover command may indicate the TCI state of the target (or candidate) cell (as shown in Figures 8 and 9).

[0261] In one example, the UE may select one of the activated UL TCI states for UL transmission of measurement reports to the target (or candidate) cell. When the measurement report is sent to the target (or candidate) cell, the target (or candidate) cell may decide whether to perform a handover. A handover command (MAC CE or DCI) to the UE is sent from the source cell. The handover command may indicate the TCI state of the target (or candidate) cell (as shown in Figures 8 and 9).

[0262] At step 1670 of Figure 16, UE 1603 may initiate a handover, or may make a decision about the handover based on measurements performed at the UE using measurement reference signals from a source cell and one or more target (or candidate) cells. In one example, the UE initiating a handover may be event triggered. In one example, the UE initiating a handover may not be event based.

[0263] At step 1680 of FIG. 16 , in order to request or perform or trigger or initiate a handover, the UE 1620 provides a message to the network (which is shown as a measurement report in FIG. 16 ). In one example, the message may be a measurement report, and the measurement report may include a flag or information element (IE) indicating that the UE requests or is triggering or is initiating a handover to a target (or candidate) cell. The IE may include a target (or candidate) cell index, or the target (or candidate) cell may be implicitly determined (e.g., a cell with an indicated TCI state or a cell with an activated TCI state (other than the source cell)). In another example, the message may be a measurement report, and the measurement report may include only measurement pairs associated with the target (or candidate) cell. The measurement report may include a flag indicating that the UE requests or is triggering or is initiating a handover to a target (or candidate) cell. Alternatively, there may be no flag, and the handover to the target (or candidate) cell is implicitly determined. In another example, the message is a measurement report, and the measurement report may include measurement pairs associated from multiple cells. The first measurement pair (i.e., the measurement pair with the best metric) may be associated with the target (or candidate) cell. The measurement report may include a flag indicating that the UE requests or is triggering or is initiating a handover to the target (or candidate) cell. Alternatively, there may be no flag and the handover to the target (or candidate) cell is implicitly determined. In another example, the message may include an information element of the target (or candidate) cell to which the UE requests or is triggering or is initiating a handover.

[0264] At step 1680 of Figure 16, the message provided by UE 1603 to request or perform or trigger or initiate handover may be sent to the target (or candidate) cell. In one example, the message provided by the UE to request or perform or trigger or initiate handover may be periodically configured. In one example, the message may be semi-persistently configured, using a dynamic signal (e.g., controlled by MAC CE or L1) to activate or deactivate the transmission of the message. In one example, the message may be triggered aperiodically using a dynamic signal (e.g., controlled by MAC CE or L1). In one example, the message may be UE-initiated; for example, the UE may send a scheduling request for UL resources to send the message, or the UE may send the message in a configured grant (a grant configured by type 1 or type 2) resource, or the UE may send the message using a random access procedure (e.g., a type 1 random access procedure or a type 2 random access procedure).

[0265] In one example, a message provided by the UE to request or perform or trigger or initiate a handover may be reported in uplink control information (UCI) in a physical uplink control channel (PUCCH). In one example, if the PUCCH overlaps with a physical uplink shared channel (PUSCH), the PUCCH may not be sent and the UCI may be multiplexed into the PUSCH. In one example, a message provided by the UE to request or perform or trigger or initiate a handover may be reported in UCI in the PUSCH. In one example, a message provided by the UE to request or perform or trigger or initiate a handover may be reported in a MAC CE. In one example, the message may be reported in a single-stage UCI. In another example, the message may be reported in a two-stage UCI.

[0266] In one example, a message (eg, a measurement report) from the UE triggers a handover to a target (or candidate) cell after a cell switching time (delay), as shown in FIG. 17 .

[0267] FIG17 shows an example method 1700 for switching to a target (or candidate) cell after a cell switching time according to the present disclosure. The example method of switching shown in FIG17 is for illustration only. Other embodiments of the switching method may be used without departing from the scope of the present disclosure.

[0268] Although Figure 17 shows one example of a method 1700 for switching to a target (or candidate) cell after a cell switching time, various changes may be made to Figure 17. For example, although shown as a series of steps, the various steps in Figure 17 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0269] In one example (Example 2 in FIG. 17), the cell switching time (delay) may come from a message from the UE indicating or requesting or triggering or initiating a switch (this may be on the PUCCH or PUSCH (UCI or MAC CE) as previously described). The cell switching time may come from the end of the message (Example 2 in FIG. 17) or from the beginning of the message. In another example (Example 1 in FIG. 17), the cell switching time (delay) may come from an acknowledgment of a UE message indicating or requesting or triggering or initiating a switch. The cell switching time may come from the end of an ACK message (Example 1 in FIG. 17) or from the beginning of an ACK message. In one example, the ACK message may be a DCI format on a PDCCH sent by the network in response to a message from the UE (e.g., a measurement report). In another example, the ACK message may be a DL transmission (e.g., PDCCH+PDSCH or MAC CE) sent by the network in response to a message from the UE.

[0270] At step 1690 of FIG. 16 , information is exchanged between the source cell 1601 and the target (or candidate) cell 1602 to complete the handover at the cell switching time.

[0271] Although Figure 16 shows an example of a method 1600 based on UE-initiated handover, various changes may be made to Figure 16. For example, although shown as a series of steps, the various steps in Figure 16 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0272] FIG. 18 shows an example method 1800 for UE-initiated cell switching according to an embodiment of the present disclosure. The embodiment of the method shown in FIG. 18 is for illustration only. One or more of the components shown in FIG. 18 may be implemented in a dedicated circuit configured to perform the functions, or one or more of the components may be implemented by one or more processors that execute instructions to perform the functions. Other embodiments of UE-initiated cell switching may be used without departing from the scope of the present disclosure.

[0273] As shown in FIG. 18 , method 1800 starts from step 1810. At step 1810, the UE receives configuration information of a reference signal associated with measurement of one or more candidate cells. At step 1820, the UE receives configuration information of a transmission configuration indicator (TCI) state list associated with one or more candidate cells. At step 1830, the UE performs measurement on the reference signal. At step 1840, the UE determines a measurement report based on the measurement.

[0274] At step 1850, the UE sends a measurement report. In one embodiment, the measurement report may include L×M measurements. L may refer to the number of cells included in the measurement report. M may refer to the number of measurements reported for each of the multiple cells in the measurement report. In another embodiment, the measurement report may include a reference signal ID and a corresponding measured L1-reference signal received power (L1-RSRP). In yet another embodiment, the measurement report is included in uplink control information (UCI) and sent on a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH).

[0275] Although Figure 18 shows an example of a method 1800 for UE-initiated cell switching, various changes may be made to Figure 18. For example, although shown as a series of steps, the various steps in Figure 18 may overlap, occur in parallel, occur in a different order, or occur any number of times.

[0276] Nothing in the description in this application should be read as implying that any particular element, step, or function is an essential element that must be included in the claims scope. The scope of the patented subject matter is limited solely by the claims.

Claims

1. A user equipment (UE), comprising: Transceiver; as well as a processor coupled to the transceiver and configured to: receiving configuration information of a reference signal associated with measurement of one or more candidate cells; receiving configuration information of a transmission configuration indicator (TCI) state list associated with the one or more candidate cells; performing measurements on a reference signal; determining a measurement report based on the measurement; as well as Send measurement reports, in: The measurement report includes L×M measurements, L is the number of cells included in the measurement report, M is the number of measurements reported for each of the multiple cells in the measurement report, The measurement report includes the reference signal ID and the corresponding measured L1-reference signal received power (L1-RSRP), and The measurement report is included in uplink control information (UCI) sent on the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH).

2. The UE according to claim 1, wherein: The reference signal includes a synchronization signal / physical broadcast channel (SS / PBCH) block of the one or more candidate cells.

3. The UE according to claim 1, wherein: The cell among the plurality of cells in the measurement report is a serving cell.

4. The UE according to claim 1, wherein: The processor is also configured to receive a medium access control-control element MAC CE from the candidate cell to activate the TCI state of the target cell.

5. The UE according to claim 1, wherein: The processor is also configured to: receiving a channel indicating a TCI status of a target cell; and The cell switching is performed after the beam application time from the end time of the reception of the HARQ-ACK of the channel indicating the TCI state of the target cell.

6. The UE according to claim 1, wherein: The processor is further configured to send a message including a request to perform a cell handover to a target cell.

7. The UE according to claim 6, wherein: The processor is also configured to: receiving an acknowledgement of the message; and The cell switching is performed after the beam application time from the confirmed end time.

8. A base station (BS), comprising: Transceiver; as well as a processor coupled to the transceiver and configured to: sending configuration information of a reference signal associated with measurement of one or more candidate cells, sending configuration information of a transmission configuration indicator (TCI) state list associated with the one or more candidate cells, and Receive measurement reports, in: The measurement report includes L×M measurements, L is the number of cells included in the measurement report, M is the number of measurements reported for each of the multiple cells in the measurement report, The measurement report includes the reference signal ID and the corresponding measured L1-reference signal received power (L1-RSRP), and The measurement report is included in uplink control information (UCI) received on the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH).

9. The BS according to claim 8, wherein: The reference signal includes a synchronization signal / physical broadcast channel (SS / PBCH) block of the one or more candidate cells.

10. The BS according to claim 8, wherein: A cell among the multiple cells in the measurement report is a serving cell.

11. The BS according to claim 8, wherein: The processor is also configured to: determining the TCI status of the target cell from the candidate cells to be activated; and A Medium Access Control-Control Element (MAC CE) is sent indicating an activated TCI state.

12. The BS according to claim 8, wherein: The processor is also configured to: Determine the TCI status of the target cell from the candidate cells; Send a channel indicating the TCI status; and The cell switching is performed after the beam application time from the end time of the reception of the HARQ-ACK of the channel indicating the TCI state of the target cell.

13. The BS according to claim 8, wherein: The processor is also configured to: receiving a message including a request to perform a cell handover to a target cell; Sending an acknowledgment of the message; and The cell switching is performed after the beam application time from the confirmed end time.

14. A method performed by a user equipment (UE), the method comprising: receiving configuration information of a reference signal associated with measurement of one or more candidate cells; receiving configuration information of a transmission configuration indicator (TCI) state list associated with the one or more candidate cells; performing measurements on a reference signal; determining a measurement report based on the measurement; as well as Send measurement reports, in: The measurement report includes L×M measurements, L is the number of cells included in the measurement report, M is the number of measurements reported for each of the multiple cells in the measurement report, The measurement report includes the reference signal ID and the corresponding measured L1-reference signal received power (L1-RSRP), and The measurement report is included in the Uplink Control Information (UCI) which is sent on the Physical Uplink Control Channel (PUCCH) or the Physical Uplink Shared Channel (PUSCH).

15. A method performed by a base station, the method comprising: sending configuration information of a reference signal associated with measurement of one or more candidate cells, sending configuration information of a transmission configuration indicator (TCI) state list associated with the one or more candidate cells, and Receive measurement reports, in: The measurement report includes L×M measurements, L is the number of cells included in the measurement report, M is the number of measurements reported for each of the multiple cells in the measurement report, The measurement report includes the reference signal ID and the corresponding measured L1-reference signal received power (L1-RSRP), and The measurement report is included in uplink control information (UCI) received on the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH).

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