Measurement event configuration for enabling L1 / 2 mobility and measurement reporting using MAC CE

Abstract

A wireless transmit / receive unit (WTRU) is configured to receive a radio resource control (RRC) message, the radio resource control (RRC) message including an indication of channel configuration information of one or more candidate cells associated with inter-cell mobility, and a wireless transmit / receive unit (WTRU) configured to receive the RRC message, the RRC message including an indication of channel configuration information of the one or more candidate cells associated with inter-cell mobility, performing a measurement on each of the candidate cells within the subset of the one or more candidate cells; determining whether each candidate cell of the candidate cells within the subset of the one or more candidate cells satisfies an event trigger criterion; and transmitting a second L1 / L2 control message, the second L1 / L2 control message including an indication of whether each of the candidate cells within the subset of the one or more candidate cells satisfies the event trigger criterion and an associated measurement for each of the candidate cells within the subset.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 395,240, filed on August 4, 2022, the entire contents of which are incorporated herein by reference. Background Art

[0003] Mobility based on L1 / L2 indications may be achieved by a WTRU transmitting RRC measurement reports and a CU making mobility decisions and notifying the DU to transmit corresponding L1 / L2 indications. However, this implementation may not achieve equal latency reduction. Therefore, what is needed is a mechanism that enables the network to trigger L1 / L2 mobility without involving RRC measurements and reporting to the CU. The present disclosure relates to devices, methods and systems for implementing measurement event configuration for L1 / 2 mobility and measurement reporting. Summary of the invention

[0004] The WTRU may be configured with an enhanced measurement and reporting configuration to allow relative signal level comparisons between serving cells, including relative signal level comparisons between an SCell and a SpCell, two SCells, and multiple SCells and a PCell. A wireless transmit / receive unit (WTRU) may include a processor. The processor may be configured to receive a radio resource control (RRC) message including an indication of channel configuration information of one or more candidate cells associated with inter-cell mobility, an index for identifying the one or more candidate cells, and an event triggering criterion for performing measurement evaluation of the one or more candidate cells. The processor may also be configured to receive a first layer 1 or layer 2 (L1 / L2) control message including an indication that the WTRU will activate measurement of a subset of the one or more candidate cells. The processor may also be configured to perform the measurement on each of the candidate cells in the subset of the one or more candidate cells, the measurement providing an associated measurement value for each of the candidate cells in the subset of the one or more candidate cells. The processor may be further configured to determine whether each of the candidate cells in the subset of the one or more candidate cells meets the event triggering criteria based on the associated measurement value of each of the candidate cells in the one or more candidate cells. The processor may be further configured to transmit a second L1 / L2 control message including an indication of whether each of the candidate cells in the subset of the one or more candidate cells meets the event triggering criteria and the associated measurement value of each of the candidate cells in the subset of the one or more candidate cells that meet the event triggering criteria.

[0005] The event triggering criteria may include a minimum radio quality threshold. The minimum radio quality threshold may be an absolute value compared to a specific cell (SpCell) within the subset of the one or more candidate cells, or a relative value compared to a specific cell (SpCell) within the subset of the one or more candidate cells.

[0006] The event triggering criteria may include a comparison between the associated measurement value of the candidate cell selected from the subset of the one or more candidate cells and an associated measurement value of a specific cell (SpCell) within the subset of the one or more candidate cells.

[0007] The event triggering criteria may include a comparison of an associated measurement value of the serving cell with an associated measurement value of a specific cell (SpCell) within the subset of the one or more candidate cells.

[0008] The associated measurement value of each of the candidate cells within the subset of the one or more candidate cells may include an offset compared to the associated measurement value of a particular cell (SpCell) within the subset of one or more candidate cells.

[0009] The first L1 / L2 control message and the second L1 / L2 control message may include a Medium Access Control Element (MAC CE).

[0010] The second L1 / L2 control message may include a bitmap indicating whether each candidate cell in the subset of the one or more candidate cells satisfies the event triggering criterion. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0012] Figure 1B is an example of a method that can be used according to an embodiment of the present invention. Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an illustrated communication system.

[0013] Figure 1C is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of an example Radio Access Network (RAN) and an example Core Network (CN) for use within the illustrated communication system.

[0014] Figure 1D is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of another example RAN and another example CN for use within the illustrated communication system.

[0015] Figure 2is a process diagram illustrating an example New Radio (NR) handover scenario.

[0016] Figure 3 is a process diagram illustrating an example CHO configuration and execution.

[0017] Figure 4 is a functional model illustrating example L1 / L2 inter-cell mobility operations using CA.

[0018] Figure 5A An example MAC CE structure for transmitting measurement reports is illustrated.

[0019] Figure 5B An example mapping for absolute power measurement reporting is illustrated.

[0020] Fig. 6A A further example MAC CE structure for transmitting measurement reports is illustrated.

[0021] Figure 6B An example mapping for absolute power measurement reporting is illustrated.

[0022] Figure 6C An example mapping for relative power measurement reporting is illustrated.

[0023] Figure 7 Another example MAC CE structure for conveying an example measurement report is illustrated.

[0024] Figure 8 is a process diagram illustrating an example message sequence.

[0025] Fig. 9 is a flow chart illustrating example WTRU procedures for CHO configuration and execution. DETAILED DESCRIPTION

[0026] Figure 1A 1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multi-carrier (FBMC), etc.

[0027] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the UE 102a, 102b, 102c, 102d (any of which WTRUs may be referred to as “stations” and / or “STAs”) may be configured to send and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smart phones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated process chain environments), consumer electronic devices, and devices operating on commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, 102d may be interchangeably referred to as WTRUs.

[0028] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device that is configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0029] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSC), radio network controllers (RNC), relay nodes, etc. Base station 114a and / or base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of a licensed spectrum and an unlicensed spectrum. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0030] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0031] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0032] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA) that may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-APro).

[0033] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0034] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, for example using the dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0035] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0036] Figure 1AThe base station 114b in may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial venues, homes, vehicles, campuses, industrial facilities, sky corridors (e.g., for use by drones), and roads. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology (such as IEEE 802.11) to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology (such as IEEE 802.15) to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0037] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the text and video, the CN 106 / 115 may be configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Figure 1A Although not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0038] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0039] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0040] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0041] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC) and state machine, etc. The processor 118 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0042] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from a base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV, or visible light signal. In another embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0043] Although the transmit / receive element 122 Figure 1B Although depicted as a single element in the figure, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0044] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0045] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, and a secure digital (SD) memory card, among others. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0046] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0047] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0048] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, module, FM radio unit, digital music player, media player, video game player module, Internet browser, virtual reality and / or augmented reality (VR / AR) device and activity tracker, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor; geolocation sensor; altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor and / or humidity sensor.

[0049] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference via hardware (e.g., a choke) or via signal processing performed by a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0050] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0051] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0052] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, and scheduling of users in the UL and / or DL, among other things. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0053] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0054] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0055] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during an inter-evolved Node-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0056] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0057] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0058] Although the WTRU Figures 1A to 1D Although described as wireless terminals, it is contemplated that in certain representative embodiments, such terminals may (eg, temporarily or permanently) use a wired communications interface with a communications network.

[0059] In a representative embodiment, the other network 112 may be a WLAN.

[0060] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and destined for the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and destined for a target outside the BSS may be transmitted to the AP to be delivered to the corresponding target. Traffic between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit traffic to the AP, and the AP may deliver traffic to the target STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic may be transmitted between the source STA and the target STA (e.g., directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (eg, all STAs in the STA) may communicate directly with each other. This IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0061] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP may send a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may listen to the primary channel. If the primary channel is listened / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0062] A high throughput (HT) STA may communicate using a 40 MHz wide channel (eg, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels) to form a 40 MHz wide channel.

[0063] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and the data can be sent by sending STA. At the receiver of the receiving STA, the above-mentioned operation for 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0064] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support instrument type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0065] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only a 1MHz operating mode) is transmitting to the AP, the entire available band may be considered busy even if most of the band remains idle and may be available.

[0066] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0067] Figure 1D1 is a system diagram illustrating the RAN 113 and the CN 115 in accordance with an embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0068] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0069] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with parameter sets that may be scalable. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing different numbers of OFDM symbols and / or varying absolute time lengths over time).

[0070] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeB 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0071] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b and routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0072] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0073] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, and / or services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0074] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0075] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring, etc.

[0076] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and the N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0077] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein for one or more of the following items may be performed by one or more simulation devices (not shown): WTRU102a-102d, base station 114a-114b, evolved Node B 160a-160c, MME 162, SGW 164, PGW 166, gNB 180a-180c, AMF 182a-182ab, UPF 184a-184b, SMF 183a-183b, DN 185a-185b and / or any other device described herein. The simulation device may be one or more devices configured to mimic one or more or all of the functions described herein. For example, the simulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0078] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0079] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which can include one or more antennas) can be used by the simulation device to send and / or receive data.

[0080] Figure 2 is a process diagram 200 illustrating an example NR handover scenario. At 202, an access and mobility function (AMF) may provide mobility control information. For a WTRU within a source gNB, the provided mobility control information may include information about roaming and / or access restrictions. The information about roaming and / or access restrictions may be provided to the WTRU at connection establishment and / or timing advance (TA) update.

[0081] At 204, the source gNB may configure the WTRU measurement control and reporting process, and / or the WTRU may report the measurement results according to the measurement configuration.

[0082] At 206, the source gNB may decide to hand over the WTRU based on the reported measurement results.

[0083] At 208, the source gNB may issue a handover request message to the target gNB. For example, the source gNB may issue the handover request message by passing a transparent RRC container with necessary information to prepare for the handover on the target side. The necessary information may include at least the target cell ID, KgNB*, the C-RNTI of the WTRU in the source gNB 204, the RRM configuration including the WTRU inactive time, the basic AS configuration including antenna information and DL carrier frequency, the current QoS flow to DRB mapping rules applied to the WTRU, SIB1 from the source gNB, WTRU capabilities for different RATs, PDU session related information, and / or WTRU reported measurement information including beam related information (if available).

[0084] At 210, the target gNB may perform admission control. If the WTRU is admitted, the target gNB may prepare for handover with L1 / L2.

[0085] The target gNB may transmit a Handover Request Confirm message to the source gNB at 212. The Handover Request Confirm message may include a transparent container that will be transmitted to the WTRU as an RRC message to perform the handover.

[0086] At 214, the source gNB may trigger a Uu handover at the WTRU. For example, the source gNB may transmit an RRCReconfiguration message to the WTRU to initiate the Uu handover. The RRCReconfiguration message may contain information required to access the target cell. For example, the RRCReconfiguration message may include at least a target cell ID, a new C-RNTI, and / or a target gNB security algorithm identifier for a selected security algorithm. The RRCReconfiguration message may also include a set of dedicated RACH resources, an association between RACH resources and SSBs, an association between RACH resources and WTRU-specific CSI-RS configurations, common RACH resources, and system information of the target cell.

[0087] The source gNB may transmit an SN status transfer message to the target gNB at 216. The SN status transfer message to the target gNB may convey an uplink PDCP SN receiver status and / or a downlink PDCP SN transmitter status for the DRBs to which PDCP status preservation (e.g., for RLC AM) is applied.

[0088] At 218, the WTRU may detach from the old cell (e.g., source gNB) and synchronize to the target cell (e.g., target gNB).

[0089] At 220, the WTRU may complete the RRC handover by transmitting an RRCReconfigurationComplete message to the target gNB.

[0090] At 222, the target gNB may transmit a path switch request message to the AMF to trigger the 5GC. The path switch request message may be transmitted to trigger the 5GC to switch the DL data path towards the target gNB and / or establish an NG-C interface instance towards the target gNB.

[0091] At 224, the 5GC may switch the DL data path toward the target gNB.

[0092] At 226, the UPF may transmit one or more "end marker" packets to the source gNB on the old path for each PDU session / tunnel and / or release any U-Plane / TNL resources towards the source gNB.

[0093] At 228, the AMF may acknowledge the Path Switch Request message with a Path Switch Request Acknowledge message.

[0094] At 230, upon receiving the Path Switch Request Ack message from the AMF, the target gNB may transmit a UE Context Release message to notify the source gNB of the handover success. The source gNB may release the radio and C-plane related resources associated with the WTRU context. Any ongoing data forwarding may continue.

[0095] NR introduces the concepts of Conditional Handover (CHO) and Conditional PSCell Addition / Change (CPA / CPC, or collectively referred to as CPAC) to help reduce the likelihood of Radio Link Failure (RLF) and Handover Failure (HOF).

[0096] Legacy LTE / NR handovers are typically triggered by measurement reports. However, the network may transmit a HO command without the WTRU needing to receive a measurement report. For example, when the radio signal level / quality (RSRP, RSRQ, etc.) of a neighboring cell becomes better than the primary serving cell (PCell), the WTRU may be configured with event A3 that triggers the measurement report to be transmitted. In the case of dual connectivity (DC), event A3 may trigger a measurement report when the RSRP of a neighboring cell becomes better than the primary secondary serving cell (PSCell). The WTRU may monitor the serving cell and neighboring cells and transmit measurement reports when conditions are met. When such a report is received, the network (e.g., the current serving node / cell) may prepare a HO command (e.g., an RRC reconfiguration message with reconfigurationWithSync) and transmit the HO command to the WTRU. The WTRU may immediately execute the HO command to connect the WTRU to the target cell.

[0097] In some operational aspects, CHO may be different from the old-style handover. For example, in the old-style handover, only one handover target is prepared. In CHO, multiple handover targets may be prepared.

[0098] As another example, in a legacy handover, the handover is performed immediately. In CHO, the handover may not be performed immediately. In contrast, in CHO, the WTRU may be configured with trigger conditions, which may include a set of radio conditions. When one or more of the trigger conditions are met, the WTRU may perform a handover toward one of the targets.

[0099] The CHO command may be transmitted when the radio conditions for the current serving cell are favorable, thereby reducing certain failure points present in legacy handovers. Failure points may include a failure to transmit a measurement report (e.g., if the link quality to the current serving cell falls below an acceptable level when the measurement report is triggered in a legacy handover). Failure points may include a failure to receive a handover command (e.g., if the link quality to the current serving cell falls below an acceptable level after the WTRU transmits the measurement report but before the WTRU receives the HO command).

[0100] Figure 3 300 is a process diagram illustrating an example CHO configuration and execution. At 302, a source node may send a CHO request message to a potential target node. At 304, the target node may send a CHO request confirmation message to the source node. For example, the CHO request confirmation message may be an RRC reconfiguration message.

[0101] At 306, the source node may send a CHO configuration message to the WTRU. For example, the CHO configuration message may include a trigger condition within an RRC reconfiguration message. The trigger condition may include an Event A3 and / or Event A5 trigger condition. The trigger condition for CHO may be based on the radio quality of the serving cell and / or neighboring cells, similar to the conditions used in legacy NR / LTE for triggering measurement reports. For example, the WTRU may be configured with CHO with a trigger condition similar to Event A3 and / or an associated HO command.

[0102] The WTRU may monitor the CHO conditions for the target cell candidates at 308. For example, the WTRU may monitor the current cell and the serving cell.

[0103] If it is determined that the trigger condition is met, the WTRU may perform a HO command at 310. For example, when the Event A3 trigger condition is met, the WTRU may perform a HO command and switch its connection to the target cell without transmitting a measurement report.

[0104] At 312, the WTRU may send a CHO confirmation to the target node.

[0105] At 314, the target node may perform a path switch and WTRU context release.

[0106] In an embodiment, CHO may prevent unnecessary re-establishment in the event of a radio link failure. For example, for a WTRU configured with multiple CHO targets and the WTRU experiences RLF before the triggering conditions with any target cell are met, the legacy handover operation will cause an RRC re-establishment procedure. This procedure may result in a significant outage time for the WTRU's bearers. Alternatively, after detecting an RLF, a WTRU configured with CHO may directly execute a HO command associated with a target cell that already has an associated CHO (e.g., the target cell is ready for handover), rather than continuing with the full re-establishment procedure.

[0107] In an embodiment, CPC and CPA may be extensions of CHO in a DC scenario. For example, a WTRU may be configured with a trigger condition for a PSCell change or addition. When the trigger condition is met, the WTRU may directly execute the associated PSCell change or PSCell addition command.

[0108] In an embodiment, the WTRU may be configured for inter-cell L1 / L2 mobility. In 3GPP's NR Release 16 (R16), the WTRU may be configured to use inter-cell L1 / L2 mobility to manage one or more beams in the case of carrier aggregation (CA). However, in 3GPP's NR Release 17 (R17), cell changes or cell additions are not supported.

[0109] In 3GPP's NR Release 18 (R18), one of the goals of the WI "Further Enhancements to NR Mobility" in RP-213565 is to specify mechanisms and procedures for L1 / L2-based inter-cell mobility with reduced mobility delay. For example, in order to specify mechanisms and procedures for L1 / L2-based inter-cell mobility with reduced mobility, multiple candidate cells may be configured and maintained to allow for rapid application of the configuration of the candidate cells. As another example, candidate serving cells (e.g., SpCells and SCells) may include dynamic switching mechanisms for potential applicable scenarios based on L1 / L2 signaling [RAN2, RAN1]. As another example, in order to specify mechanisms and procedures for L1 / L2-based inter-cell mobility with reduced mobility, L1 enhancements for inter-cell beam management are provided, including L1 measurements and reporting and beam indications [RAN1, RAN2]. Early RAN2 involvement may be necessary, including further clarification of the possibility of interaction between L1 enhancements for inter-cell beam management and dynamic switching mechanisms between candidate serving cells. As another example, timing advance management may be provided to specify mechanisms and procedures for L1 / L2 based inter-cell mobility with reduced mobility [RAN1, RAN2]. Further, in order to specify mechanisms and procedures for L1 / L2 based inter-cell mobility with reduced mobility, CU-DU interface signaling supporting L1 / L2 mobility may be provided.

[0110] The procedures for L1 / L2 based inter-cell mobility are applicable to multiple scenarios, including standalone, CA and NR-DC cases with serving cell change within one CG; intra-DU case and intra-CU inter-DU case (e.g. applicable to standalone and CA: no new RAN interface is expected), both intra-frequency and inter-frequency, FR1 and FR2, and synchronized or unsynchronized source and target cells. For L1 / L2 based inter-cell mobility procedures, inter-CU may be included. FR2 specific enhancements are not excluded.

[0111] R17 includes L1 / L2-based mobility and inter-cell beam management in addressed intra-DU and intra-frequency scenarios. In these scenarios, the serving cell remains unchanged (e.g., it is not possible to change the serving cell using L1 / L2-based mobility). In FR2 deployments, CA is typically used to take advantage of the available bandwidth, such as aggregating multiple CCs in one band. These CCs are typically transmitted with the same analog beam pair (e.g., gNB beam and UE beam). The WTRU may be configured with TCI states for receiving PDCCH and PDSCH. For example, the WTRU may be configured with a relatively large number (e.g., 64) of TCI states. Each TCI state may include an RS or SSB that the WTRU can use to set its beam.

[0112] In R17, an SSB may be associated with a non-serving PCI. MAC signaling (e.g., "TCI state indication for WTRU-specific PDCCH MAC CE") may activate the TCI state for Coreset / PDCCH. Reception of PDCCH from non-serving cells is supported by indicating a MAC CE for the TCI state associated with the non-serving PCI. MAC signaling (e.g., "TCI state activation / deactivation for WTRU-specific PDSCH") may activate a subset of (e.g., up to) 8 TCI states for PDSCH reception. The DCI may indicate which of the 8 TCI states are activated. R17 supports "unified TCI states" with different update mechanisms (e.g., DCI-based) but without multiple TRPs. R18 supports unified TCI states with multiple TRPs.

[0113] The overall goal of L1 / L2 inter-cell mobility may be to improve handover latency. In a normal or conditional L3 handover, the WTRU typically first transmits a measurement report using RRC signaling. In response to the measurement report, the network may provide additional measurement configurations and potential conditional handover configurations.

[0114] In a regular L3 handover, the network may provide the configuration for the target cell after the WTRU reports using RRC signaling to indicate that the cell meets the configured radio quality criteria. In a conditional L3 handover, the network may provide the target cell configuration and the measurement criteria that determine when the WTRU should trigger the CHO configuration. These criteria may be provided in advance to help reduce the handover failure rate due to delays in transmitting measurement reports and / or receiving RRC reconfiguration. However, a regular or conditional L3 handover may incur some delays due to the transmission of measurement reports and the reception of the target configuration, especially in the case of a regular (non-conditional) handover.

[0115] A specific purpose of L1 / L2 based inter-cell mobility configuration may be to allow fast application of configuration for candidate cells, including dynamic switching between SCells and switching of PCells (e.g., switching roles between SCells and PCells), without performing RRC signaling. However, this mobility configuration may not be applicable to inter-CU handovers, as these handovers may require relocation of the PDCP anchor point. Therefore, an RRC based approach may still be needed to support inter-CU handovers.

[0116] In the old L3 handover mechanism, any currently active SCell is released before the WTRU completes the handover to the target cell in the coverage area of ​​the new site. The released SCell may be added back only after a successful handover, causing a decrease in throughput during the handover. Therefore, one of the purposes of L1 / L2 is to enable CA operation immediately upon serving cell change.

[0117] Figure 4 408 is a functional model 400 illustrating example L1 / L2 inter-cell mobility operations using CA. As shown in the functional model 400, as the WTRU 402 physically traverses cell 1 (e.g., 3.5 GHz) 404, cell 2 (e.g., 2.1 GHz) 406, cell 3 (e.g., 26 GHz) 408, and cell 4 (e.g., 26 GHz) 410, the WTRU may switch between candidate cells. At a first position 412, using CA, the WTRU 402 may initially be configured with cell 1 404 as a primary cell (e.g., PCell 1) and cell 2 408 as a secondary cell (e.g., SCell 2). At this position 412, RRC measurements and reports may have configured cells 1-4 404, 406, 408, 410 as candidate cells. Once configured, cell 1 404 may be activated as a primary cell and cell 2 406 may be activated as a secondary cell. At a second position 414, the WTRU 402 may dynamically switch its secondary cell to cell 3 408 (e.g., SCell 3). At a third position 416, the WTRU 402 may dynamically switch its secondary cell to cell 2 406 (e.g., SCell 2). At a fourth position 418, the WTRU 402 may dynamically switch its primary cell to cell 2 406 (e.g., PCell 2) and its secondary cell to cell 4 410 (e.g., SCell 4). The candidate cell group within the functional model 400 may be configured through RRC messages, and dynamic switching of PCells and SCells may be implemented using L1 / L2 signaling.

[0118] In order to achieve fast switching between cells (e.g., SpCell (PCell and / or PSCell)), candidate cells may be pre-configured at the RRC level so that these configurations can be applied when an indication is received from an L1 / L2 message. The candidate cell may have a configuration for one or more candidate cells (e.g., at least one of SpCell or SCell), which may be dynamically applied based on an indication at a lower layer (e.g., L1 / L2).

[0119] Mobility decisions (e.g., mobility decisions related to SCell addition / removal, SCell change, SpCell change, and CHO configuration) may be configured based on measurement reports (e.g., events) completed at the RRC level. For example, if the WTRU reports event A2 (e.g., service becomes worse than a threshold), CHO may be configured. As another example, a SpCell change (e.g., HO) may be initiated based on the WTRU transmitting a measurement report triggered by the completion of event A3 (e.g., neighbor becomes better than SpCell offset) or event A5 (e.g., SpCell becomes worse than a first threshold and neighbor becomes better than a second threshold). As another example, if the WTRU transmits a measurement report triggered by the completion of event A4 (e.g., neighbor cell becomes better than a threshold), SCell addition may be performed. As another example, a SCell change may be performed based on the completion of event A6 (e.g., neighbor cell becomes better than SCell offset).

[0120] In legacy NR operation, if a CU-DU split architecture is adopted, L1 measurement results are reported to the DU (e.g., CQI report), which is suitable for scheduling purposes. Since any cell change or reconfiguration requires a lot of processing, cell changes or reconfigurations should not be performed too frequently based on L1 signaling. In addition, cell changes or reconfigurations should be performed when stable measurement results are used to determine reconfiguration decisions. L3 measurement results (e.g., measurements filtered at L3 to filter out short-term fluctuating measurements) are therefore used to make mobility decisions. The L3 measurement results are transmitted to the CU, where the RRC is terminated. Based on the L3 measurement results, the RRC of the CU may transmit a reconfiguration message instructing the WTRU to perform mobility operations (e.g., HO command for immediate mobility, CHO for mobility when certain conditions are met, etc.).

[0121] One way to implement L1 / L2 indication based mobility may be that the WTRU transmits RRC measurement reports, the CU makes a mobility decision, and the CU notifies the DU to transmit the corresponding L1 / L2 indication. However, such an implementation may conflict with one of the main goals of L1 / L2 mobility (e.g., latency reduction). Therefore, a mechanism may be needed to enable the network to trigger L1 / L2 mobility without involving RRC level signaling (e.g., at the MAC / PHY level; at the DU in case of a CU-DU split architecture).

[0122] In an embodiment, the WTRU may be configured to implement low latency L1 / L2 mobility that does not involve RRC level signaling for both UL and DL. The WTRU may be configured with an enhanced measurement report / event configuration that may perform relative signal level comparisons between serving cells. For example, the WTRU may be configured with an enhanced measurement report / event configuration that may perform relative signal level comparisons between serving cells. Relative signal level comparisons may be performed between various cell types and configurations (e.g., SCell to SpCell, two SCells, several SCells to PCell, all SCells to PCell, etc.).

[0123] In an embodiment, the WTRU may be configured to implement L1 / L2 handover from SCell to SpCell or vice versa. The WTRU may be configured to transmit concise L3 layer measurements at the MAC layer (e.g., MAC CE). The WTRU may be configured to enable MAC layer HO decisions at the network (e.g., without involving the CU).

[0124] The WTRU may be configured to perform some mobility decisions at the DU to help reduce latency when using L1 / L2 mobility. For example, for intra-DU PCell changes, the DU may make mobility decisions. Therefore, latency may be significantly improved by reporting measurements to the DU rather than the CU (e.g., similar to measurements made at L3) so that the DU can manage intra-DU handovers. While reporting measurements to the DU, some L3 measurements may be reported to the CU (e.g., via RRC measurement reports) so that the CU can manage inter-DU or inter-CU handovers. Reporting measurements at the RRC implies increased latency due to factors such as MAC and RLC retransmissions and transmitting reports over multiple TTIs. Therefore, it may be advantageous to define a more dynamic way of reporting measurements.

[0125] The L3 measurement event may not contain all the necessary evaluation methods required to perform some L1 / L2 triggered reconfiguration procedures. The L3 measurement report may be configured with a measurement identifier associated with the measurement object (e.g., identifying the carrier to be measured and the attributes of the carrier) and a reporting criteria (e.g., the conditions to be monitored / evaluated). The defined measurement events are configured so that the WTRU compares the configured measurement object (i.e., the neighboring cell) with the serving cell. In an L1 / 2 triggered reconfiguration, the ability to change the role of the serving cell (e.g., from SCell to PCell, or vice versa) provides for comparison of serving cells with each other. In an embodiment, the WTRU may be configured to compare candidate cells (e.g., which may not be configured as a serving cell at this time) with the serving cell, and to compare neighboring cells with candidate cells.

[0126] In an embodiment, the WTRU may use a measurement reporting method.In addition, the WTRU may be configured to utilize a new set of measurement events to evaluate the criteria for performing L1 / L2 triggered reconfiguration.

[0127] In an embodiment, the WTRU may be configured with a new measurement event.A measurement event may be triggered based on the WTRU comparing a serving cell (or a set of serving cells) with the current SpCell.

[0128] A measurement event may be associated with an SCell and a threshold level. For example, when the SCell becomes superior to the SpCell by more than a configured threshold, the WTRU may trigger a measurement report.

[0129] A measurement event may be associated with multiple SCells and a threshold level. For example, when one or more SCells become superior to the SpCell by more than a configured threshold, the WTRU may trigger a measurement report.

[0130] A measurement event may be associated with multiple SCells and a threshold level. For example, when all SCells become superior to the SpCell beyond a configured threshold, the WTRU may trigger a measurement report.

[0131] A measurement event may be associated with a number of SCells and a threshold level. For example, when a certain number of SCells becomes superior to a SpCell beyond a configured threshold, the WTRU may trigger a measurement report. A specific number of SCells may be associated with an event.

[0132] A measurement event may be associated with a plurality of SCells and a threshold level. For example, when a certain percentage of SCells (eg, configured within the event) become superior to the SpCell by more than a threshold level, the WTRU may trigger a measurement report.

[0133] A measurement event may include a combination of one or more configurations of measurement reports, and the threshold level may be unique or different for each SCell.

[0134] In an embodiment, the measurement event configuration may include absolute threshold levels associated with the SpCell, serving cell, and / or candidate cell. For example, a measurement event may be associated with an SCell and a threshold level. When the SCell becomes better than a threshold level, the WTRU may trigger a measurement report.

[0135] A measurement event may be associated with multiple SCells and a threshold level. For example, when one or more of the SCells becomes better than a threshold level, the WTRU may trigger a measurement report.

[0136] A measurement event may be associated with multiple SCells and a threshold level. For example, when all SCells become better than a threshold level, the WTRU may trigger a measurement report.

[0137] A measurement event may be associated with a number of SCells and a threshold level. For example, when a certain number of SCells becomes better than a threshold level, the WTRU may trigger a measurement report. A certain number of SCells may be associated with an event.

[0138] A measurement event may be associated with a plurality of SCells and a threshold level. For example, when a certain percentage of SCells becomes better than a threshold level, the WTRU may trigger a measurement report. A certain percentage of SCells may be associated with a measurement event.

[0139] The measurement may include a combination of one or more configurations of measurement reports, and the threshold level may be unique or different for each SCell.

[0140] In an embodiment, the measurement event configuration may be associated with periodic reporting. For example, for a relative threshold, the WTRU may periodically trigger a measurement report to indicate which of the SCells are better than the SpCells by exceeding the configured absolute relative threshold. For an absolute threshold, the WTRU may periodically trigger a measurement report to indicate which of the SCells are better than the configured absolute threshold.

[0141] The WTRU may be configured to perform periodic reporting where the WTRU indicates the best N serving cells (eg, SpCell and N-1 best SCells, best N cells regardless of whether the cell is a SpCell or a SCell, and similar combinations).

[0142] In an embodiment, the WTRU may be configured to transmit a measurement report indicating the best N serving cells that meet a certain absolute threshold (e.g., SpCell and N-1 best SCells, best N cells regardless of whether the cell is a SpCell or a SCell, and similar combinations).

[0143] The WTRU may be configured to transmit measurement reports periodically or when the WTRU detects that N cells satisfy a condition. The WTRU may be configured to perform periodic reporting indicating the best N cells that satisfy a certain relative threshold compared to the SpCell (e.g., SpCell and N-1 best SCells, best N cells regardless of whether the cell is a SpCell or a SCell, and similar combinations). The WTRU may be configured to transmit measurement reports periodically or when the WTRU detects that N cells satisfy a condition.

[0144] In an embodiment, one or more measurement event solutions may be applied to a SCell, a candidate cell, or a set of candidate cells.

[0145] In an embodiment, the WTRU may be configured to use MAC CE for measurement reporting. The WTRU may be configured to use regular RRC measurement reporting to transmit measurement reports triggered based on event configuration. Alternatively or additionally, the WTRU may be configured to use MAC CE (e.g., using any of the example solutions discussed below) to transmit measurement reports triggered based on event / report configuration.

[0146] Figure 5A An example MAC CE bitmap 500A for transmitting a measurement report is illustrated. The bitmap 500A may be configured to indicate which candidate cells and / or serving cells are being reported. In an embodiment, each bit 502 of the bitmap 500A may correspond to an index configured in the RRC, including, for example, servingCellIndex, SCellIndex, or a new index such as candidateCellIndex.

[0147] The "1" bit 502 may indicate that the measurement result for the cell is included. For example, the "1" bit 502 may indicate that this cell measurement result is above an absolute threshold associated with the event configuration. The threshold may be configured by RRC or may be predefined. The "1" bit 502 may further indicate that the cell measurement result is above a relative threshold (e.g., the cell measurement result is within X dB of SpCell). The "1" bit 502 may further indicate that the cell has triggered a specific measurement event.

[0148] In an embodiment, the WTRU may be configured to report up to the N best cells (e.g., a "1" may be signaled for the best ranked N cells based on the cell measurement results) 504. Similarly, the WTRU may be configured to report up to the N best cells above a threshold (e.g., a "1" may be signaled for up to N cells).

[0149] In an embodiment, the MAC CE may contain a simple bitmap or identifier (e.g., an index) that communicates which cells meet certain criteria (e.g., to minimize reporting overhead). Alternatively or additionally, measurement results may be included in the MAC CE for some or all of the cells indicated in the bitmap (e.g., to improve reporting accuracy). For example, the WTRU may include measurement results for each cell indicated as "1" in the bitmap.

[0150] Figure 5BAn example mapping 500B for absolute power measurement reporting is illustrated. The example mapping 500B may include an absolute RSRP value (e.g., a measurement result) 506 and a corresponding power report value 508. For example, the measurement result 506 itself may be in a simplified form 508, such as may be defined as one of 64 values ​​corresponding to a power level. The WTRU may report a value corresponding to the highest power value supported by the cell measurement. For example, if there are values ​​of -90 dB and -95 dB and the WTRU measures -92 dB, the WTRU may report a value corresponding to -95 dB.

[0151] In an embodiment, the order of the measurement results may correspond to the order of the cell indices within the MAC CE bitmap that have been indicated with a "1." In such a configuration, SpCell measurements may be included so that the network can compare the candidate cell results with the SpCell.

[0152] Fig. 6A Another example MAC CE bitmap 600A for transmitting measurement reports is illustrated. The bitmap 600A may be configured with SpCell measurements 602 reported as absolute power, while measurements 604 of other cells may be reported as relative power (e.g., offset from the SpCell measurements). The bitmap 600A configuration may enable reporting of more cells using fewer bits.

[0153] In an embodiment, the WTRU may use one bit 614 (eg, the "S" bit) to indicate whether the offset is positive or negative compared to the SpCell 602, and the remaining 3 bits in this report may correspond to 7 values, for example.

[0154] Figure 6B An example mapping 600B for absolute power measurement reporting is illustrated. The example mapping 600B may include an absolute RSRP value (e.g., a measurement result) 606 and a corresponding power report value 608. For example, the measurement result 606 itself may be in a simplified form 608, such as being defined as one of 64 values ​​corresponding to a power level.

[0155] Figure 6C An example mapping 600C for relative power measurement reporting is illustrated. The example mapping 600C may include RSRP offset values ​​610 and corresponding power offset reporting values ​​612. For example, relative power 610 may be conveyed with a smaller range of possible reporting values ​​612, and thus report more cells using fewer bits.

[0156] Figure 7Another example MAC CE mapping 700 for transmitting an example measurement report is illustrated. In an embodiment, the WTRU may indicate a "1" for all cells that meet a predefined criterion, such as an absolute power threshold. The WTRU may include results for only the best N cells. The WTRU may be configured to include a measurement event identifier.

[0157] like Figure 7 As shown, the MAC CE mapping 700 may include a cell index 702 and a power value 704. The MAC CE may include an identifier corresponding to a measurement identification or measurement event ID 706. For example, measurement event A3 may be configured for a specific candidate cell. A measurement event may be triggered when a candidate cell becomes better than the SpCell. The measurement event ID 706 may identify the candidate cell that triggered the event, or may include additional indicators to identify which specific cells triggered the event. Along with an indication that the event has been triggered, the WTRU may include measurement results for one or more of the PCell 708, the cell that triggered the event 704, and the next N best cells 710.

[0158] In L1 / L2 triggered mobility, the WTRU may be configured to change the role between SpCell and SCell. In an embodiment, a new type of measurement event may be required to compare serving cells (e.g., SCell and SpCell). For example, a measurement event may be triggered when the SCell becomes superior to the SpCell or the SCell becomes superior to the SpCell offset. In the current RRC measurement event, the WTRU may be configured to compare the neighboring cell with the serving cell. In some cases, the WTRU may not compare serving cells with each other.

[0159] In an embodiment, the WTRU may receive a DL MAC CE that activates measurements for a specific set of cells or requests reports for a specific set of cells. In response, the WTRU may perform measurements and transmit reports using one or more formats, referencing the index of the set of cells indicated in the DL MAC CE. For example, the DL MAC CE may indicate a subset of cells (e.g., 8) from a list of all (e.g., 32) candidate cells. The WTRU may transmit results in the uplink corresponding to the cells indicated in the DL (e.g., for a subset of cells; 8 cells).

[0160] In an embodiment, the measurement report in the MAC CE may correspond to the cell configuration. For example, the report may include the SpCell identifier. In addition, the report may include the SpCell identifier based on whether the cell is the best cell or based on whether the cell has triggered a specific event.

[0161] In an embodiment, the report may include one or more SCell identities. For example, the report may include one or more SCell identities based on the cells being the next N best cells or based on the cells satisfying a second or another criterion.

[0162] In an embodiment, the network may respond with an acknowledgment in the downlink. For example, as an acknowledgment in the downlink of a MAC CE "activates" the WTRU's proposed configuration. Thus, based on the configured criteria, the WTRU may select which cells should be activated as serving cells and what the roles of these cells should be.

[0163] In an embodiment, after reporting to the network which cells should be activated, the network may confirm using a truncated MAC CE activation command or provide an alternative configuration in a more explicit MAC CE command. For example, the network may select a serving cell configuration different from the configuration reported by the WTRU, the network selection being based on one or more factors (e.g., load, interference, etc.).

[0164] Figure 8 is a process diagram 800 illustrating an example message sequence.

[0165] The network may configure the candidate cell set and measurement report identifier for MAC-based measurement reporting and MAC-triggered reconfiguration. Candidate cell establishment and measurement control may be configured using separate messages. Candidate cell establishment and measurement control may be performed in a single configuration message. Measurement may be enabled based on RRC configuration only. MAC CE may be used to further activate or request measurements.

[0166] like Figure 8 As shown, the NW may provide the WTRU with an RRC configuration at 802. In an embodiment, the RRC configuration information may indicate a list of one or more candidate cells.

[0167] At 804, the NW may provide measurement control to the WTRU. The measurement control may include candidate cell measurements. The WTRU may perform measurements and evaluations based on the configured criteria defined in the provided measurement control. When the configured criteria are met, the WTRU may trigger a MAC CE measurement report. For example, the WTRU may determine that the configured criteria are met when a specific measurement event is triggered, measurement results become available, or in response to a request.

[0168] The WTRU may report the MAC CE measurement results to the NW at 806. For example, the WTRU may report cell 2 as the best cell (or preferred PCell) and cells 0 and 3 as the next best cells (or preferred SCells).

[0169] The NW may confirm or activate the configuration based on the WTRU report at 808. For example, the NW may provide a MAC CE cell activation command to the WTRU, and the NW may activate cell 2 as PCell and cells 0 and 3 as SCells.

[0170] In an embodiment, the NW may advantageously split mobility decisions between the DU and the CU. The DU may manage cell changes in the DU (i.e., intra-DU) based on measurements reported at the MAC layer. The DU may activate RRC reconfiguration for cell changes using commands transmitted at the MAC layer. At the same time, the CU may manage mobility across different DUs (inter-DU) using conventional RRC measurement reporting and reconfiguration. Alternatively or additionally, the DU may report MAC measurements to the CU for the CU to perform mobility management similar to L3 mobility performed during conventional handovers.

[0171] The embodiments disclosed herein provide a method for reporting fast measurement events and cell measurement results so that the network can make handover and cell reconfiguration decisions. The embodiments discussed herein support fast triggering of candidate cell role changes in downlink.

[0172] Fig. 9 is a flow chart 900 illustrating an example WTRU process for CHO configuration and execution. At 902, the WTRU receives configuration information using a first signaling method. For example, the first signaling method may be RRC messaging.

[0173] In an embodiment, the configuration information may include channel configuration information for one or more candidate cells for performing L1 / L2 mobility. The configuration information may also include an index for identifying one or more candidate cells. The configuration information may also include event triggering criteria for performing measurement evaluation on one or more candidate cells. The event triggering criteria may include a single event triggering criteria applied to all one or more candidate cells. Alternatively or additionally, the event triggering criteria may include individual triggering event criteria defined for each of the one or more candidate cells.

[0174] The WTRU receives a first layer 1 or layer 2 (L1 / L2) control message at 904. The control message may include an indication that the WTRU is to activate measurements on a subset of one or more candidate cells.

[0175] The WTRU performs measurements on each of the candidate cells in the subset of one or more candidate cells at 906. The measurements of the candidate cells provide associated measurement values ​​for each of the candidate cells in the subset of one or more candidate cells.

[0176] The WTRU determines whether each of the candidate cells in the subset of the one or more candidate cells satisfies the event triggering criteria at 908. The determination may be based on associated measurement values ​​of each of the candidate cells in the one or more candidate cells.

[0177] The WTRU transmits a second L1 / L2 control message at 910. The control message includes an indication of whether each of the candidate cells in the subset of one or more candidate cells meets the event triggering criteria and an associated measurement value for each of the candidate cells in the subset of one or more candidate cells that meets the event triggering criteria.

Claims

1. A wireless transmit / receive unit (WTRU), the wireless transmit / receive unit (WTRU) comprising: A processor, the processor being configured to: receiving a radio resource control (RRC) message including an indication of channel configuration information of one or more candidate cells associated with inter-cell mobility, an index for identifying the one or more candidate cells, and an event triggering criterion for performing measurement evaluation of the one or more candidate cells; receiving a first layer 1 or layer 2 (L1 / L2) control message including an indication that the WTRU is to activate measurement of a subset of the one or more candidate cells; performing the measuring for each of the candidate cells within the subset of the one or more candidate cells, the measuring providing an associated measurement value for each of the candidate cells within the subset of the one or more candidate cells; determining, based on the associated measurement value of each of the candidate cells in the one or more candidate cells, whether each of the candidate cells in the subset of the one or more candidate cells satisfies the event triggering criterion; as well as transmitting a second L1 / L2 control message including an indication of whether each of the candidate cells within the subset of the one or more candidate cells meets the event triggering criteria and the associated measurement value of each of the candidate cells within the subset of the one or more candidate cells that meets the event triggering criteria.

2. The WTRU of claim 1 , wherein the event triggering criteria comprises a minimum radio quality threshold.

3. The WTRU according to claim 2, wherein the minimum radio quality threshold is an absolute value compared to a specific cell (SpCell) within the subset of the one or more candidate cells, or a relative value compared to a specific cell (SpCell) within the subset of the one or more candidate cells.

4. A WTRU according to claim 1, wherein the event triggering criterion includes a comparison between an associated measurement value of a candidate cell selected from the subset of the one or more candidate cells and an associated measurement value of a specific cell (SpCell) within the subset of the one or more candidate cells.

5. The WTRU of claim 1 , wherein the processor is further configured to: performing measurements of a serving cell, the measurements providing associated measurement values ​​of the serving cell; and Whether the event triggering criteria are met is determined by comparing the associated measurement value of the serving cell with the associated measurement value of a specific cell (SpCell) within the subset of one or more candidate cells.

6. The WTRU of claim 1 , wherein the processor is further configured to: performing measurements of a plurality of serving cells, the measurements providing associated measurement values ​​for each of the plurality of serving cells; and Whether the event triggering criteria are met is determined by comparing the associated measurement value of each of the plurality of serving cells with the associated measurement value of a specific cell (SpCell) within the subset of one or more candidate cells.

7. A WTRU according to claim 1, wherein the associated measurement value of each candidate cell in the subset of the one or more candidate cells includes an offset relative to the associated measurement value of a specific cell (SpCell) within the subset of the one or more candidate cells.

8. The WTRU of claim 1, wherein the first L1 / L2 control message and the second L1 / L2 control message comprise a medium access control element (MAC CE).

9. The WTRU of claim 8, wherein the second L1 / L2 control message comprises a bitmap indicating whether each of the candidate cells within the subset of the one or more candidate cells satisfies the event triggering criteria.

10. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: receiving a radio resource control (RRC) message including an indication of channel configuration information of one or more candidate cells associated with inter-cell mobility, an index for identifying the one or more candidate cells, and an event triggering criterion for performing measurement evaluation of the one or more candidate cells; receiving a first layer 1 or layer 2 (L1 / L2) control message including an indication that the WTRU is to activate measurement of a subset of the one or more candidate cells; performing the measuring for each of the candidate cells within the subset of the one or more candidate cells, the measuring providing an associated measurement value for each of the candidate cells within the subset of the one or more candidate cells; determining, based on the associated measurement value of each of the candidate cells in the one or more candidate cells, whether each of the candidate cells in the subset of the one or more candidate cells satisfies the event triggering criterion; as well as transmitting a second L1 / L2 control message including an indication of whether each of the candidate cells within the subset of the one or more candidate cells meets the event triggering criteria and an associated measurement value for each of the candidate cells within the subset of the one or more candidate cells that meets the event triggering criteria. The method of claim 11 , wherein the event triggering criteria comprises a minimum radio quality threshold.

12. The method according to claim 12, wherein the minimum radio quality threshold is an absolute value compared to a specific cell (SpCell) within the subset of the one or more candidate cells, or a relative value compared to a specific cell (SpCell) within the subset of the one or more candidate cells.

13. The method of claim 11, wherein the event triggering criteria comprises a comparison between an associated measurement value of a candidate cell selected from the subset of the one or more candidate cells and an associated measurement value of a specific cell (SpCell) within the subset of the one or more candidate cells.

14. The method according to claim 11, further comprising: performing measurements of a serving cell, the measurements providing associated measurement values ​​of the serving cell; as well as Whether the event triggering criteria are met is determined by comparing the associated measurement value of the serving cell with the associated measurement value of a specific cell (SpCell) within the subset of one or more candidate cells.

15. The method according to claim 11, further comprising: performing measurements of a plurality of serving cells, the measurements providing associated measurement values ​​for each of the plurality of serving cells; as well as Whether the event triggering criteria are met is determined by comparing the associated measurement value of each of the plurality of serving cells with the associated measurement value of a specific cell (SpCell) within the subset of one or more candidate cells.

16. The method of claim 11, wherein the associated measurement value of each of the candidate cells within the subset of the one or more candidate cells comprises an offset relative to the measurement value of a specific cell (SpCell) within the subset of the one or more candidate cells.

17. The method of claim 11, wherein the first L1 / L2 control message and the second L1 / L2 control message are medium access control elements (MAC CEs).

18. The method of claim 17, wherein the second L1 / L2 control message comprises a bitmap indicating whether each of the candidate cells within the subset of the one or more candidate cells satisfies the event triggering criteria.

Images