Method and apparatus for dynamic spectrum sharing

Abstract

To provide a method of sharing spectrum with LTE by a new wireless technology.SOLUTION: A wireless transmit / receive unit (WTRU) is configured to monitor physical downlink control channel (PDCCH) candidates for a primary cell (PCell) and a secondary cell (SCell), to determine a duration for a PDCCH candidate budget for a set of symbols on the basis of a subcarrier spacing associated with the PCell and a subcarrier spacing associated with the SCell, and to determine a maximum number of PDCCH candidates to allocate for search space monitoring opportunities for the PCell and the SCell. The maximum number of PDCCH candidates may be based on a per-cell ratio. The WTRU may be configured to allocate PDCCH candidates for the search space monitoring opportunities for the PCell and the SCell on the basis of the determined maximum number of PDCCH candidates, and to decode the allocated PDCCH candidates.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 061,611, filed Aug. 5, 2020; U.S. Provisional Patent Application No. 63 / 168,080, filed Mar. 30, 2021; and U.S. Provisional Patent Application No. 63 / ...

Background Art

[0002] The new Radio (NR) technology is defined by 3GPP and is designed to provide high flexibility for both control channels and data channels. For control channels, NR supports different monitoring patterns and different physical downlink control channel (PDCCH) locations within a slot....

[0003] In NR, it has been proposed to share the spectrum with Long Term Evolution (LTE). Sharing the spectrum with LTE would require semi-statically reserving physical resources, at least for the LTE control region. This could reduce the capacity of NR primary cells (PCells) transmitting downlink control signaling, and also reduce the available resources for data within a slot, as the control region should precede the data region. Supporting NR secondary cell (SCell) scheduling for NR PCells would introduce reliability issues for downlink control information. Furthermore, supporting control channels on SCell scheduling data on PCells could prevent WTRUs from simultaneously receiving or monitoring control channels on both cells due to increased blind decoding effort. Therefore, a method is needed for NR to efficiently share the spectrum with LTE. [Overview of the project]

[0004] A wireless transmit / receive unit (WTRU) may be configured to monitor physical downlink control channel (PDCCH) candidates for primary cells (PCell) and secondary cells (SCell). The WTRU may be configured to determine the duration for the PDCCH candidate budget for a set of symbols based on the subcarrier interval associated with the PCell and the subcarrier interval associated with the SCell. The WTRU may be configured to determine the maximum number of PDCCH candidates to allocate to the PCell and SCell search space monitoring opportunities. The maximum number of PDCCH candidates may be based on a per-cell ratio. The WTRU may be configured to allocate PDCCH candidates for the PCell and SCell search space monitoring opportunities based on the determined maximum number of PDCCH candidates. The WTRU may be configured to decode the allocated PDCCH candidates.

[0005] The WTRU may be configured to determine whether there are overlapping PCell and SCell search space monitoring opportunities in the symbol set, and may be configured to determine the maximum number of PDCCH candidates to allocate, provided that there are overlapping search space monitoring opportunities. The ratio per cell may be determined based on the number of configured PDCCH candidates on PCell (N1) and the number of configured downlink control channel candidates on SCell (N2). The maximum number of PDCCH candidates for PCell may be based on the number of configured PDCCH candidates for PCell (N1) as a percentage of the total number of configured PDCCH candidates for PCell and SCell (N1+N2). The maximum number of PDCCH candidates for SCell may be based on the number of configured PDCCH candidates for SCell (N2) as a percentage of the total number of configured PDCCH candidates for PCell and SCell (N1+N2). The WTRU may be configured to prioritize the search spaces to monitor based on search space priority or search space index. [Brief explanation of the drawing]

[0006] A more detailed understanding can be obtained from the following description, which is given as an example in conjunction with the attached drawings, where similar reference numbers in the drawings indicate similar elements. [Figure 1A] This is a system diagram showing an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] This is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) that may be used in the communication system shown in Figure 1A, according to one embodiment. [Figure 1C] This is a system diagram showing an exemplary radio access network (RAN) and an exemplary core network (CN) that may be used in the communication system shown in Figure 1A according to one embodiment. [Figure 1D] This is a system diagram showing further exemplary RAN and further exemplary CN that may be used in the communication system shown in Figure 1A according to one embodiment. [Figure 2] This section illustrates an example of switching between monitoring patterns. [Figure 3] This section illustrates an example of switching between monitoring patterns. [Figure 4] An example of the WTRU switching between the first monitoring pattern, the transition time, and the second monitoring pattern is shown. [Figure 5] An exemplary method for switching control channels is shown. [Figure 6] This document provides an exemplary method for monitoring PDCCH candidates for PCell and SCell in order to schedule PCell. [Figure 7] This figure shows the maximum number of PDCCH BDs / non-overlapping CCEs for PCell scheduling. [Figure 8] This is an example demonstrating the dynamic determination of the maximum PDCCH candidate for each scheduling cell. [Figure 9] This example demonstrates search space prioritization using search space priority. [Figure 10] This example demonstrates search space prioritization using search space indices. [Modes for carrying out the invention]

[0007] Figure 1A shows an exemplary 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, message transmission, and broadcast to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may use 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 discrete Fourier transform spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filter OFDM, and filter bank multicarrier (FBMC).

[0008] As shown in Figure 1A, the communication system 100 may include radio transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the internet 110, and other networks 112, but it will be understood that the disclosed embodiments intend any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d may be any type of device configured to operate and / or communicate in a radio environment. For example, WTRU102a, 102b, 102c, and 102d, all of which may be referred to as stations (STA), may be configured to transmit and / or receive radio signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscriber-based units, pagers, mobile phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, 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 an industrial and / or automated processing chain context), consumer electronic devices, and devices operating on commercial and / or industrial wireless networks. Any of WTRU102a, 102b, 102c, and 102d may interchangeably be referred to as UE.

[0009] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of the base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks such as CN 106, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be next-generation node B such as base transceiver station (BTS), node B, eNode B (eNB), home node B, home eNode B, gNode B (gNB), new radio (NR) node B, site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are shown as single elements, it will be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0010] Base station 114a may be part of RAN 104, which may also include other base stations such as a base station controller (BSC), a radio network controller (RNC), relay nodes, and / or network elements (not shown). Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies which may be referred to as cells (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. Cells may provide coverage of radio services to a particular geographic area which may be relatively fixed or change over time. Cells may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver per sector of the cell. In one embodiment, the base station 114a may use multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0011] Base stations 114a and 114b may communicate with one or more WTRUs 102a, 102b, 102c, and 102d via an air interface 116, which may be any suitable radio 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).

[0012] More specifically, as described above, the communication system 100 may be a multiple access system and may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base stations 114a of RAN 104 and WTRU 102a, 102b, 102c may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish an air interface 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (HSUPA).

[0013] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c may implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish an air interface 116 using Long-Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0014] In one embodiment, the base station 114a and WTRUs 102a, 102b, and 102c may implement radio technologies such as NR radio access, which may establish an air interface 116 using NR.

[0015] In one embodiment, base station 114a and WTRU 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRU 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Thus, the air interface utilized by WTRU 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to and from multiple types of base stations (e.g., eNB and gNB).

[0016] In other embodiments, base stations 114a and WTRUs 102a, 102b, and 102c may implement wireless 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, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0017] The base station 114b in FIG. 1A can be, for example, a wireless router, a home node B, a home e-node B, or an access point, and can utilize any suitable RAT to facilitate wireless connections in a local area such as an office, a home, a vehicle, a campus, an industrial facility, an aerial corridor (for use by drones, for example), a location such as a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless 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 can utilize a cellular-based RAT (such as WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As shown in FIG. 1A, the base station 114b can have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106.

[0018] RAN104 may communicate with CN106, 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 WTRU102a, 102b, 102c, and 102d. The data may have various quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. CN106 may provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video distribution, etc., and / or high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN104 and / or CN106 may communicate directly or indirectly with other RANs using the same RAT or different RAT as RAN104. For example, in addition to being connected to RAN104 which may utilize NR radio technology, CN106 may also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0019] CN106 may also function as a gateway for WTRU102a, 102b, 102c, 102d to access the PSTN108, the Internet 110, and / or other networks 112. The PSTN108 may include a public switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, and these networks and devices use a common communication protocol such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs that may use the same or a different RAT as the RAN 104.

[0020] Some or all of the WTRU102a, 102b, 102c, 102d in the communication system 100 may include multimode capabilities (e.g., the WTRU102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, the WTRU102c shown in FIG. 1A may be configured to communicate with a base station 114a that may use a cellular-based wireless technology and a base station 114b that may use IEEE802 wireless technology.

[0021] Figure 1B is a system diagram showing an exemplary WTRU102. As shown in Figure 1B, the WTRU102 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 supply 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU102 may include any partial combination of the aforementioned elements while maintaining consistency with one embodiment.

[0022] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple 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), any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, 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 a transceiver 120 which may be coupled to a transmit / receive element 122. Figure 1B shows the processor 118 and transceiver 120 as separate components, but it will be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0023] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of radio signals.

[0024] Although the transmit / receive element 122 is shown as a single element in Figure 1B, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize 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 radio signals via the air interface 116.

[0025] The transceiver 120 may be configured to modulate the signal transmitted by the transmit / receive element 122 and demodulate the signal received by the transmit / receive element 122. As described above, the WTRU 102 may have multimode capability. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0026] The processor 118 of the WTRU102 may be coupled to 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) and may receive user input from these. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Furthermore, the processor 118 may access information from any type of suitable memory, such as non-removable memory 130 and / or removable memory 132, and store data in such memory. The non-removable memory 130 may include random-access memory (RAM), 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, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown), and store data in such memory.

[0027] The processor 118 may receive power from the power supply 134, but may also be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 may be any suitable device for supplying power to the WTRU 102. For example, the power supply 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.), a solar cell, a fuel cell, etc.

[0028] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to or instead of the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via 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 understood that the WTRU 102 may acquire location information by any preferred location determination method while maintaining consistency with one embodiment.

[0029] The processor 118 may be further coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. Peripherals 138 may include one or more sensors. The sensor 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, barometer, gesture sensor, biometric sensor, humidity sensor, etc.

[0030] WTRU102 may include a full-duplex radio in which the transmission and reception of some or all of a signal (for example, associated with specific subframes of both UL (for example, for transmission) and DL (for example, for reception) may occur simultaneously and / or together. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via hardware (e.g., chokes) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, WTRU102 may include a half-duplex radio for the transmission and reception of some or all of a signal (for example, associated with specific subframes of either UL (for example, for transmission) or DL ​​(for example, for reception)).

[0031] Figure 1C is a system diagram illustrating RAN104 and CN106 according to one embodiment. As described above, RAN104 can communicate with WTRU102a, 102b, and 102c via the air interface 116 using E-UTRA wireless technology. RAN104 can also communicate with CN106.

[0032] RAN104 may include e-nodes B160a, 160b, and 160c, but it will be understood that RAN104 may include any number of e-nodes B while maintaining consistency with one embodiment. Each of e-nodes B160a, 160b, and 160c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, e-nodes B160a, 160b, and 160c may implement MIMO technology. Thus, e-node B160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU102a.

[0033] Each of the e-nodes B160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling, etc., in UL and / or DL. As shown in Figure 1C, the e-nodes B160a, 160b, and 160c may communicate with each other via the X2 interface.

[0034] The CN106 shown in Figure 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although these elements are shown as part of CN106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0035] The MME162 can be connected to each of the e-nodes B162a, 162b, and 162c in RAN104 via the S1 interface and can function as a control node. For example, the MME162 may perform roles such as authenticating users of WTRU102a, 102b, and 102c, activating / deactivating bearers, and selecting gateways for specific services during the initial attachment of WTRU102a, 102b, and 102c. The MME162 may provide control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0036] The SGW164 can be connected to each of the e-nodes-B160a, 160b, and 160c in RAN104 via the S1 interface. The SGW164 can generally route and forward user data packets to and from WTRU102a, 102b, and 102c. The SGW164 can perform other functions, such as anchoring the user plane during e-node-B handovers, triggering paging when DL data is available to WTRU102a, 102b, and 102c, and managing and remembering the context of WTRU102a, 102b, and 102c.

[0037] SGW164 may be connected to PGW166, which may provide WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0038] CN106 can facilitate communication with other networks. For example, CN106 can provide WTRU102a, 102b, and 102c with access to a circuit-switched network such as PSTN108 to facilitate communication between WTRU102a, 102b, and 102c and conventional terrestrial line communication devices. For example, CN106 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that acts as an interface between CN106 and PSTN108. Furthermore, CN106 may provide WTRU102a, 102b, and 102c with access to another network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0039] Although the WTRU is shown as a wireless terminal in Figures 1A to 1D, in certain representative embodiments, such a terminal is intended to be able to use a wired communication interface with a communication network (e.g., temporarily or permanently).

[0040] In a typical embodiment, the other network 112 may be a WLAN.

[0041] A WLAN in Basic Service Set (BSS) mode may have access points (APs) of the BSS and one or more stations (STAs) associated with the APs. APs may have access to or interfaces with a Distribution System (DS) or another type of wired / wireless network that carries traffic within and / or outside the BSS. Traffic originating outside the BSS and destined for an STA may reach and be delivered to the STA via an AP. Traffic originating from an STA to a destination outside the BSS may be sent to an AP and then delivered to its respective destination. Traffic between STAs within the BSS may be transmitted, for example, via an AP; a source STA may send traffic to an AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be transmitted between a source STA and a destination STA (for example, directly between them) via a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have APs, and STAs within or using IBSS (e.g., all STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as “ad hoc” communication mode.

[0042] When using the 802.11ac infrastructure operating mode or a similar operating mode, an AP may transmit beacons on a fixed channel, such as the primary channel. The primary channel may be of a fixed width (e.g., a 20 MHz bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain typical embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. In the case of CSMA / CA, the STA, including the AP (e.g., all STAs), may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that STA may be backed off. A single STA (e.g., only one station) may transmit at any given time on a given BSS.

[0043] High-throughput (HT) STAs may use a 40 MHz wide channel for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0044] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. The 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. In the 80+80 configuration, after channel coding, the data can pass through a segment parser that can split the data into two streams. Inverse Fast Fourier Transform (IFFT) and time-domain processing can be performed separately for each stream. The streams may be mapped to two 80 MHz channels, and the data can be transmitted by a transmitting STA. At the receiver of a receiving STA, the operation described above for the 80+80 configuration may be reversed, and the combined data may be transmitted to Medium Access Control (MAC).

[0045] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, while 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using the non-TVWS spectrum. According to a typical embodiment, 802.11ah may support meter-type control / machine-type communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, including support for specific and / or limited bandwidths (e.g., support only for that). MTC devices may include batteries with battery life exceeding a threshold (e.g., to maintain very long battery life).

[0046] A WLAN system capable of supporting multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes a channel that can be designated as the primary channel. 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 an STA from among all STAs operating in a BSS that support the minimum bandwidth operating mode. In the 802.11ah example, the primary channel may be 1 MHz wide for an STA (e.g., an MTC type device) that supports (e.g., only) the 1 MHz mode, even if other STAs in the AP and BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, 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. For example, if the primary channel is busy, an STA (which only supports 1MHz operating mode) sending to the AP may consider the entire available frequency band to be busy, even if most of the available frequency band is idle.

[0047] In the United States, the available frequency band that can be used by 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.

[0048] Figure 1D is a system diagram showing RAN104 and CN106 according to one embodiment. As described above, RAN104 can communicate with WTRU102a, 102b, and 102c via the air interface 116 using NR radio technology. RAN104 can also communicate with CN106.

[0049] RAN104 may include gNB180a, 180b, and 180c, but it will be understood that RAN104 may include any number of gNBs while maintaining consistency with one embodiment. Each of gNB180a, 180b, and 180c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, gNB180a, 180b, and 180c may implement MIMO technology. For example, gNB180a and 180b may use beamforming to transmit and / or receive signals to gNB180a, 180b, and 180c. Thus, gNB180a may, for example, use multiple antennas to transmit and / or receive radio signals from WTRU102a. In one embodiment, gNB180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB180a may transmit multiple component carriers to WTRU102a (not shown). A subset of these component carriers may be on the unauthorized spectrum, and the remaining component carriers may be on the authorized spectrum. In one embodiment, gNB180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU102a may receive coordinated transmissions from gNB180a and gNB180b (and / or gNB180c).

[0050] WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using transmissions associated with an expandable numerology. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of varying or expandable lengths (e.g., varying numbers of OFDM symbols and / or varying durations of absolute time).

[0051] gNB180a, 180b, and 180c can be configured to communicate with WTRU102a, 102b, and 102c in standalone and / or non-standalone configurations. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c without accessing other RANs (e.g., e-nodes B160a, 160b, and 160c). In a standalone configuration, WTRU102a, 102b, and 102c can utilize one or more of gNB180a, 180b, and 180c as mobility anchor points. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using signals in unlicensed bands. In a non-standalone configuration, WTRU102a, 102b, and 102c can communicate with and connect to gNB180a, 180b, and 180c, while also communicating with and connecting to other RANs such as enodes B160a, 160b, and 160c. For example, WTRU102a, 102b, and 102c can implement DC principles for substantially simultaneous communication with one or more gNB180a, 180b, and 180c and one or more enodes B160a, 160b, and 160c. In a non-standalone configuration, enodes B160a, 160b, and 160c can function as mobility anchors for WTRU102a, 102b, and 102c, while gNB180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRU102a, 102b, and 102c.

[0052] Each of the gNB180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slice support, interaction between DC, NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a and 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a and 182b, and so on. As shown in Figure 1D, the gNB180a, 180b, and 180c may communicate with each other via the Xn interface.

[0053] The CN106 shown in Figure 1D may include at least one AMF182a, 182b, at least one UPF184a, 184b, at least one Session Management Function (SMF)183a, 183b, and possibly a Data Network (DN)185a, 185b. Although the aforementioned elements are shown as part of CN106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0054] AMF182a and 182b can be connected to one or more of gNB180a, 180b, and 180c in RAN104 via the N2 interface and can function as control nodes. For example, AMF182a and 182b may play roles such as user authentication for WTRU102a, 102b, and 102c, support for network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selection of SMF183a and 183b for registration, management of registration areas, termination of non-access stratum (NAS) signals, and mobility management. Network slicing can be used by AMF182a and 182b to customize CN support for WTRU102a, 102b, and 102c based on the type of service utilizing WTRU102a, 102b, and 102c. For example, different network slices may be established for different use cases, such as services that rely on ultra-reliable low latency (URLLC) access, services that rely on enhanced massive mobile broadband (eMBB) access, and services for MTC access. AMF182a, 182b may provide control plane functionality for switching between RAN104 and other RANs (not shown) using other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0055] SMF183a and 183b may be connected to AMF182a and 182b in CN106 via the N11 interface. SMF183a and 183b may also be connected to UPF184a and 184b in CN106 via the N4 interface. SMF183a and 183b may select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a and 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing DL data notifications. PDU session types may be IP-based, non-IP-based, Ethernet-based, etc.

[0056] UPF184a and 184b may be connected via the N3 interface to one or more gNB180a, 180b, and 180c within RAN104, thereby providing WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices. UPF184 and 184b may perform other functions such as packet routing and forwarding, enforcement of user plane policies, support for multi-homed PDU sessions, processing of user plane QoS, buffering of DL packets, and mobility anchoring.

[0057] CN106 can facilitate communication with other networks. For example, CN106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that functions as an interface between CN106 and PSTN108. Furthermore, CN106 may provide WTRU102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRU102a, 102b, 102c may be connected to local DN185a, 185b via UPF184a, 184b through an N3 interface to UPF184a, 184b and an N6 interface between UPF184a, 184b and DN185a, 185b.

[0058] With regard to Figures 1A-1D and the corresponding descriptions in Figures 1A-1D, one or more of the functions described herein with respect to one or more of the WTRU102a-d, base stations 114a-b, e-nodes B160a-c, MME162, SGW164, PGW166, gNB180a-c, AMF182a-b, UPF184a-b, SMF183a-b, DN185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). An emulation device may be one or more devices configured to emulate one or more of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0059] Emulation devices may be designed to implement testing of one or more other devices in a laboratory and / or operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless network to test other devices in a communications network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless network. Emulation devices may be directly coupled to another device for the purpose of testing and / or performing testing using over-the-air wireless communication.

[0060] One or more emulation devices may perform one or more functions, including all of the above, while not implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device may be used in a test laboratory test scenario, and / or in a wired and / or wireless communication network that is not deployed (e.g., for testing purposes), to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation device to transmit and / or receive data.

[0061] The following abbreviations and acronyms may be referenced. CG: Configured grant or cell group DG (Dynamic Grant) CAPC Channel Access Priority Class DFI Downlink Feedback Information HARQ PID: HARQ Process ID eLAA (Enhanced Licensed Assisted Access) FeLAA Further Enhanced Licensed Assisted Access MAC CE MAC control element ACK (Acknowledgement) BLER Block Error Rate BWP (Bandwidth Part) CAP Channel Access Priority CCA Clear Channel Assessment CP Cyclic Prefix CP-OFDM (cyclic prefix dependent) is a conventional OFDM. CQI (Channel Quality Indicator) CRC Cyclic Redundancy Check CSI Channel State Information CW (Contention Window) CWS Contention Window Size CO stands for Channel Occupancy. DAI Downlink Assignment Index DCI Downlink Control Information DL Downlink DM-RS Demodulation Reference Signal DRB (Data Radio Bearer) HARQ Hybrid Automatic Repeat Request LAA License Assisted Access LBT (Listen-Before-Talk) LTE, for example, Long Term Evolution from 3GPP LTE R8 onwards. NACK (Negative ACK) MCS Modulation and Coding Scheme MIMO Multiple Input Multiple Output NR (New Radio) OFDM (Orthogonal Frequency-Division Multiplexing) PHY Physical Layer PRACH (Physical Random Access Channel) PSS Primary Synchronization Signal RACH Random Access Channel (or Random Access Procedure) RAR (Random Access Response) RCU: Radio access network Central Unit RF Wireless Front End RLF (Radio Link Failure) RLM (Radio Link Monitoring) RNTI (Radio Network Identifier) RRC (Radio Resource Control) RRM (Radio Resource Management) RS Reference Signal RSRP Reference Signal Received Power RSSI Received Signal Strength Indicator SDU (Service Data Unit) SRS Sounding Reference Signal SS Synchronization Signal SSS Secondary Synchronization Signal SWG (Switching Gap in a Self-Contained Subframe) SPS (Semi-persistent scheduling) SUL Supplemental Uplink TB Transport Block TBS Transport Block Size TRP Transmission / Reception Point TSC (Time-sensitive communications) TSN (Time-sensitive networking) UL Uplink URLLC (Ultra-Reliable and Low Latency Communications) WBWP (Wide Bandwidth Part) WLAN (Wireless Local Area Network) and related technologies (IEEE 802.xx domain)

[0062] New Radio (NR) is designed to offer higher data rates, very low latency, and several new features compared to LTE. To enable a smooth transition from LTE to NR, spectrum sharing can be used to allow both of these radio access technologies (RATs) to share the same frequency resources. The spectrum sharing feature was designed for the initial deployment of NR, which anticipated a larger number of LTE WTRUs compared to NR WTRUs. After the initial deployment of NR, it was anticipated that the number of NR WTRUs might exceed the number of LTE WTRUs, which motivated the need to redesign and expand the frequency sharing feature to enable a more efficient way of sharing spectrum between the two RAT networks.

[0063] A common deployment for NR is to have LTE cells and NR primary cells (PCells) that share the same spectrum in the lower frequency range, and to provide NR WTRUs with secondary cells (SCells) that operate in the higher frequency range so that higher data rates can be achieved.

[0064] A WTRU may be configured using control channels on both a PCell and a SCell, which can schedule data within a PCell. This specification presents embodiments of how a WTRU may monitor control channels across different cells to schedule data within a PCell. While the focus is on scheduling data on a PCell, the embodiments presented herein may also apply to other scenarios, such as control channels on a SCell and a PCell scheduling data on a SCell, as well as control channels on different SCells scheduling data on a SCell.

[0065] A scheduled cell is one on which a physical downlink shared channel (PDSCH) can be received and / or a physical uplink shared channel (PUSCH) can be transmitted. For example, a PCell can be a scheduled cell. A scheduling cell can be a cell that can schedule a scheduled cell. For example, an SCell can schedule a PCell. In another example, a scheduled PCell can schedule itself to become a scheduling cell.

[0066] In one embodiment, the WTRU may be semi-statically configured with a set of search spaces on both the PCell and SCell to schedule data on the PCell. Some search spaces, e.g., a common search space, may exist only on the PCell. It is proposed to have dynamic signaling to switch or turn off some search spaces to avoid increased effort in blind decoding while enabling dynamic load balancing. The WTRU may dynamically determine which set of search spaces and / or control channel resources to monitor. The decision of which set of search spaces and / or control channel resources to monitor may be based, for example, on monitoring WTRU-specific signaling, WTRU common signaling, patterns and scheduling activity (e.g., the WTRU may monitor a control channel on the PCell for only a certain duration, and the duration may be extended if the control channel is scheduled by the PCell), cell activation / deactivation, DRX cycles, and active BWP.

[0067] In one embodiment, the WTRU may be configured to monitor the entire search space within the SCell in order to schedule the PCell. This can lead to WTRU reachability issues. For example, if the wireless conditions on the SCell deteriorate, the WTRU may not be reachable even if the PCell wireless link is good.

[0068] In one embodiment, a WTRU can trigger monitoring of a configured search space on the PCell, which may be considered a fallback mechanism. For example, a WTRU may have a common search space for monitoring system information and other common signaling on the PCell, but this search space may not be suitable for scheduling all WTRUs (blocking probability problem). In this embodiment, a WTRU can autonomously activate the search space or begin monitoring the search space. A WTRU can autonomously activate the search space or begin monitoring the search space after, for example, a measurement, the absence of a DCI over a set time period, or a number of PDCCH opportunities (e.g., ≥1) over a set period.

[0069] In one embodiment, the WTRU may perform wireless link monitoring on the SCell. If the link quality is poor, the WTRU may switch to monitoring the control channel on the PCell and indicate or transmit a switching instruction to a network entity, such as a gNB. The instruction may include, for example,: a transmission on a specific or arbitrary PRACH resource, initiation of a RACH procedure, SR transmission, a special resource for switching instructions, SRS transmission, or triggering or inclusion of a MAC CE to indicate the SCell RLM status of the SCell. The MAC CE may be restricted to transmissions on the PCell.

[0070] Scheduling information may be an uplink grant or a downlink assignment. Properties of scheduling information may include, for example, frequency allocation, time allocation mode such as duration, priority, modulation and coding scheme, transport block size, number of spatial layers, number of transport blocks carried, TCI status, SRI, number of iterations, whether the grant is a configured grant type 1, type 2, or dynamic grant, whether the iteration scheme is type A or type B, a configured grant index or semi-persistent assignment index, periodicity of the configured grant or assignment, channel access priority class (CAPC), or any parameters provided by MAC or RRC in DCI for scheduling grants or assignments.

[0071] The properties of the data contained in a transport block (TB) can refer to any parameters that constitute a logical channel or radio bearer in which the data may be contained within the TB. For example, at least one of the following: logical channel priority, priority bitrate, logical channel group, or RLC mode.

[0072] Grant or allocation properties may refer to properties of data contained in the corresponding TB. DCI indications may include explicit indications. Explicit indications may be, for example, by DCI fields or by RNTI used to mask the CRC of PDCCH. DCI indications may include implicit indications. Implicit indications may be, for example, by properties such as DCI format, DCI size, CORESET (control resource set) or search space, aggregation level, or identification information of the first control channel resource for DCI (e.g., the index of the first CCE). Mapping between properties and values ​​may be signaled, for example, by RRC or MAC.

[0073] In one embodiment, a WTRU may be configured using a control resource set (CORESET) and / or a search space set, which may be defined across cells (i.e., the search space set and / or CORESET may have resources in both PCell and SCell). In one example, a CORESET may have interleaved resources, having a first set of frequency resources in PCell and a second set of frequency resources in SCell. In one example, a search space may be configured within a CORESET, which may have physical resources in both PCell and SCell. In one example, a search space set may be configured to have resources on two CORESETs in different cells (e.g., one CORESET on PCell and another CORESET on SCell). For example, the search space set configuration may include a parameter indicating a list of CORESETs to which the search space set belongs.

[0074] The search space configuration on a scheduling cell may include parameters that indicate one or more target cells to be scheduled. For example, the RRC configuration of the search space may include target cell IDs as part of the search space configuration. The set of search space indices on a scheduling cell may be reserved or dedicated for scheduling on the cells to be scheduled. For example, a search space with ID=0 (or IDs within a range or value) in a SCell may be reserved for scheduling on a PCell.

[0075] In one embodiment, the WTRU may use a control channel selection procedure. The control channel selection procedure may be used to determine the serving cell, bandwidth portion (BWP), search space, and / or coreset on which the PDCCH is monitored for receiving downlink control and / or scheduling information corresponding to a particular cell (e.g., PCell). Upon activation of PDCCH monitoring on a particular cell, search space, BWP, and / or coreset for scheduling a PCell, the WTRU may or may not deactivate PDCCH monitoring on the active cell, search space, BWP, and / or coreset on which the PCell is scheduled. The WTRU may be triggered to initiate the control channel selection procedure.

[0076] The WTRU may switch to, activate, or deactivate PDCCH monitoring on the serving cell, BWP, search space, and / or CORESET for receiving downlink control and / or scheduling information corresponding to a particular cell (e.g., PCell) based on at least one of the following: receiving WTRU common signaling, receiving WTRU specific signaling, receiving the number of DL signals, activating a particular DRX cycle, activating or deactivating a serving cell, activating a BWP, detecting a beam fault, declaring a radio link fault (RLF), or detecting a consistent UL LBT fault, as a function of the DRX state or timer, or as a function of a configured time domain pattern.

[0077] In one embodiment, a WTRU may, based on the reception of WTRU common signaling, switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET to receive downlink control and / or scheduling information corresponding to a particular cell. A WTRU may monitor one or more WTRU common search spaces configured on a serving cell. A WTRU may receive information on a WTRU common search space to instruct the WTRU to switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET to receive downlink control and / or scheduling information for another serving cell. The information may be an instruction, and may be explicit or implicit. The information may be received via DCI. The information may be from the properties of scheduling information. When it is determined that a certain amount of time has elapsed, the WTRU may return to monitoring a particular cell (e.g., PCell). The WTRU may start or restart a timer upon receiving information. Once the timer expires, the WTRU can return to monitoring the specific cell.

[0078] In one embodiment, a WTRU may, based on the reception of WTRU-specific signaling, switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET to receive downlink control and / or scheduling information corresponding to a particular cell. A WTRU may monitor one or more dedicated or WTRU-specific search spaces configured on a serving cell. A WTRU may receive information on a dedicated or WTRU-specific search space to instruct the WTRU to switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET to receive downlink control and / or scheduling information for another serving cell. The information may be an instruction, and may be explicit or implicit. The information may be received via DCI. The information may be from the properties of scheduling information. When it is determined that a certain amount of time has elapsed, the WTRU may return to monitoring a particular cell (e.g., PCell). The WTRU may start or restart a timer upon receiving information. Once the timer expires, the WTRU can return to monitoring the specific cell.

[0079] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control information and / or scheduling information corresponding to a particular cell, based on the reception of several DL signals compared to a threshold. The DL signals may include DCI, PDSCH, and / or PDCCH. The threshold may be predetermined or dynamically indicated. In one example, the WTRU may switch, activate, or deactivate PDCCH monitoring if the number of DL signals is below or above a threshold. In another example, the WTRU may switch, activate, or deactivate PDCCH monitoring if the number of DL signals is below or above a threshold during a specific time period.

[0080] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control information and / or scheduling information corresponding to a particular cell, based on the activation of a DRX cycle. The WTRU may switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control information and / or scheduling information relating to another serving cell after transitioning to a DRX cycle or a particular DRX cycle (e.g., a short DRX or a long DRX). In one example, the WTRU may monitor PDCCH on a PCell during the on-duration of a long DRX cycle. Upon receiving DCI or scheduling information during a particular on-duration, or upon activating a short DRX cycle, the WTRU may activate PDCCH monitoring on a SCell to schedule the PCell.

[0081] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET to receive downlink control information and / or scheduling information corresponding to a particular cell, based on the DRX state or a timer function. The WTRU may be configured or predefined to monitor PDCCH to schedule PCells on a particular cell, search space, BWP, and / or CORESET, depending on whether a DRX timer (e.g., drx inactivity timer, drx-HARQ RTT timer, data inactivity timer, and / or drx retransmission timer) is operating. In one example, the WTRU may monitor SCell for PCell scheduling if the drx inactivity timer is operating.

[0082] In one embodiment, the WTRU can switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control information and / or scheduling information corresponding to a particular cell, based on a configured time domain pattern. The WTRU can be configured as a pattern of monitoring PDCCH to schedule PCells on a particular cell, search space, BWP, and / or CORESET, as a function of time.

[0083] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control information and / or scheduling information corresponding to a particular cell, based on the activation or deactivation of a serving cell. The WTRU may start or stop monitoring a PDCCH resource associated with scheduling a particular cell when a PDCCH resource is activated or deactivated (for example, after receiving a MAC CE deactivation or activation, or after the SCell deactivation timer expires). The WTRU may stop monitoring a PDCCH resource associated with PCell scheduling if the cell on which the PDCCH resource resides is deactivated. The WTRU may start monitoring PDCCH on different SCells in order to schedule a PCell or the PCell itself.

[0084] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control information and / or scheduling information corresponding to a particular cell, based on the activation or deactivation of a BWP. The WTRU may start or stop monitoring PDCCH resources associated with the scheduling of a particular cell when a BWP in that cell is activated or deactivated (e.g., after receiving a (de)activate BWP switch command or after the BWP non-activity timer expires). The WTRU may stop monitoring PDCCH resources associated with the scheduling of a PCell if the SCell BWP on which a PDCCH resource resides is deactivated. The WTRU may start monitoring the PDCCH of a different SCell BWP (e.g., a newly active BWP on the same SCell, or a different BWP on a different active serving SCell) or the PCell itself in order to schedule the PCell. In one embodiment, the WTRU can monitor the PDCCH on the SCell for PCell scheduling if the active BWP of the UL and / or DL ​​on the PCell is from a configured subset of BWPs, the default BWP, the initial BWP, or a non-default BWP.

[0085] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control information and / or scheduling information corresponding to a particular cell, based on the detection of a beam fault. When a beam fault is detected in the cell to which a PDCCH resource belongs or on a PCell, the WTRU may start or stop monitoring the PDCCH resource associated with the scheduling of a particular cell. When a beam fault is detected on a SCell that schedules a PCell, the WTRU may start monitoring the PDCCH on a different SCell in order to schedule the PCell.

[0086] In one embodiment, a WTRU may, based on a declaration of a radio link fault (RLF), switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control and / or scheduling information corresponding to a specific cell. When an RLF is detected in a cell to which a PDCCH resource belongs or on a PCell, the WTRU may start or stop monitoring the PDCCH resource associated with the scheduling of that particular cell. When a WTRU declares an RLF on a SCell that schedules a PCell, it may start monitoring the PDCCH on a different SCell in order to schedule the PCell.

[0087] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on serving cells, BWPs, search spaces, and / or CORESETs to receive downlink control information and / or scheduling information corresponding to a particular cell, based on the detection of consistent UL listen-before-talk (LBT) failures. When a consistent UL LBT failure is detected in the cell to which the PDCCH resource belongs or on a PCell, the WTRU may start or stop monitoring the PDCCH resource associated with the scheduling of a particular cell. When a consistent UL LBT failure is detected on a SCell that schedules a PCell, the WTRU may start monitoring the PDCCH on a different SCell to schedule the PCell.

[0088] In one embodiment, the WTRU can be configured to select which downlink control channel to monitor from among the available control channels for scheduling data on the PCell. The WTRU can initiate a control channel selection procedure after being triggered by one or more of the triggers described herein.

[0089] In one embodiment, the WTRU can select one or more CORESETs to monitor. For example, the WTRU can select a CORESET within a PCell to monitor whether the number of received DL PDSCHs within the PCell falls below a set threshold for a set period of time.

[0090] In one embodiment, the WTRU can select one or more search space sets to monitor its scheduling data on the PCell. For example, the WTRU can monitor a search space set on the PCell if the SCell that schedules data on the PCell is deactivated.

[0091] In one embodiment, the WTRU can adjust the CORESET parameters. The WTRU can adjust the CORESET parameters based on one or more of the triggers described herein. For example, the WTRU may receive a DCI that triggers the WTRU to adjust one or more CORESET parameters. The CORESET parameters to be adjusted may be one or more of the following: DM-RS scrambling sequence initialization, precoder granularity, number of consecutive symbols (i.e., CORESET duration), or mapping from CCE to REG.

[0092] In one embodiment, the WTRU can adjust the parameters of the search space set. The WTRU can adjust the parameters of the search space set based on one or more triggers described herein. For example, the WTRU can receive a DCI (e.g., a common DCI) that changes the monitoring pattern of the search space set. The search space set parameters to be adjusted may be one or more of the following: monitoring periodicity, monitoring pattern within a slot, duration of monitoring pattern, number of PDCCH candidates per CCE aggregation level, or number of aggregation levels.

[0093] In one embodiment, the WTRU may be configured using a CORESET having frequency domain resources in both PCell and SCell, and a search space set associated with this CORESET. The search space set may have monitoring patterns applicable to all PDCCH / CCE resource combinations with PCell and SCell. The monitoring patterns may be configured as time domain patterns and / or frequency domain patterns (e.g., matrices where rows represent CCEs of the CORESET and columns represent symbols). The WTRU may be configured using multiple monitoring patterns for the search space set and may switch between monitoring patterns based on one or more triggers described herein.

[0094] In one embodiment, the WTRU can consist of two search space set monitoring patterns. For example, the first monitoring pattern may be for monitoring the physical resources of the search space set on both SCell and PCell for the first symbol in the slot, and for monitoring the physical resources of the search space set on SCell only for the second and third symbols in the slot. The second monitoring pattern may be for monitoring the physical resources of the search space set on both SCell and PCell for the first symbol in the slot, and for monitoring the physical resources of the search space set on PCell only for the second and third symbols in the slot. Figure 2 shows a method for switching between monitoring patterns (200). The WTRU may, for example, by default, monitor a control channel (e.g., PDCCH) with the first search space set monitoring pattern (210). The WTRU can be triggered to switch monitoring patterns (220). For example, the WTRU may receive a DCI on PCell that schedules data on PCell. The WTRU may switch to a second monitoring pattern based on a trigger (e.g., a received DCI) (230). The WTRU may use the second monitoring pattern for a set period of time. The WTRU may start a timer in response to switching to the second monitoring period. The WTRU may reset the timer when a new DCI that schedules data on the PCell is detected on the PCell. When the timer expires, or when it determines that a set period of time has elapsed, the WTRU may switch back to the first monitoring pattern (240).

[0095] In one embodiment, the WTRU can be configured using three monitoring patterns, one of which can be applied during a switching or transition time. Figure 3 shows a method for switching monitoring patterns (300). The WTRU may monitor a control channel (PDCCH) with a first monitoring pattern (310). The first monitoring pattern may be the default monitoring pattern. The WTRU may be triggered to switch monitoring patterns (320). After being triggered to change monitoring patterns, the WTRU may switch to and use a second monitoring pattern during the transition time (330). The WTRU may use a third monitoring pattern after the transition (340). The pattern configuration may include flexible symbols that may be assumed during the switching or transition time. The WTRU may be configured using monitoring behavior in the flexible symbols when triggered to switch monitoring patterns. For example, the WTRU may be configured to monitor control resources on PCell only, SCell only, or both SCell and PCell during the flexible symbols.

[0096] Figure 4 shows an example of a WTRU switching between a first monitoring pattern, a transition time, and a second monitoring pattern. The WTRU can be configured on both SCell and PCell using the first monitoring pattern. The WTRU can monitor the control channel in the first monitoring pattern in CORESET on both SCell and PCell. The WTRU can be triggered to switch the control channel. The WTRU can monitor the control channel in a transition monitoring pattern on both SCell and PCell. After monitoring in the transition monitoring pattern, the WTRU can monitor the control channel in a second monitoring pattern on both PCell and SCell.

[0097] In one embodiment, a WTRU can receive two DCIs scheduling the same data on a PCell within different control domains (e.g., one DCI in the PCell and another in the SCell). For example, during a transition from one monitoring pattern to another, a gNB can send a DCI on the PCell and another DCI on the SCell to schedule a WTRU on the PCell. This can improve the reliability of control signaling during the transition time. The WTRU can prioritize the received DCIs. The WTRU can prioritize the first DCI received. For example, when transitioning from one monitoring pattern to another, if the WTRU detects a first DCI for a particular monitoring opportunity, the WTRU can stop monitoring other PDCCH candidates during the transition time. The WTRU can prioritize the last DCI received. For example, the WTRU can receive a first DCI for a first monitoring opportunity and continue monitoring other monitoring opportunities during the transition period. If the WTRU detects a second DCI, it can prioritize that second DCI. Prioritization can help the WTRU determine which uplink control channel to use when performing uplink control channel selection.

[0098] In one embodiment, the WTRU may be configured to monitor search space sets that have several blind decoding attempts exceeding its capacity. The WTRU may prioritize or skip some search space set monitoring opportunities based on the configured maximum number of blind decodings per carrier. In one example, the WTRU may be configured using the maximum number of blind decodings per scheduled cell (i.e., the maximum number of blind decodings associated with all search space sets scheduling the cell, regardless of where the search space set is located).

[0099] In one embodiment, the WTRU may select an uplink control channel. The WTRU may be configured using an uplink control channel on the SCell (i.e., a PUCCH resource). In one example, the WTRU can use the SCell's uplink control channel when a DCI that schedules data or triggers a PCell CSI report is received in the SCell control area. For example, the WTRU may receive a scheduling DCI on the SCell that assigns a PDSCH transmission on the PCell. After decoding the PDCSH transmission on the PCell, the WTRU may report HARQ ACK / NACK feedback on the PUCCH on the SCell. In one example, the WTRU may report HARQ ACK / NACK feedback on the PUCCH on the PCell for a scheduling DCI received on the PCell. In one example, the WTRU may be configured to transmit a non-periodic CSI report on the PCell on the PUCCH on the SCell when a trigger DCI is received on the SCell. In one example, the WTRU may be configured to receive an explicit bit field in the DCI indicating which cell to use for the PUCCH transmission.

[0100] In one embodiment, the WTRU may determine which uplink control channel to use (e.g., PUCCH on SCell or PUCCH on PCell) based on the monitoring opportunity in which a scheduling DCI or trigger DCI is received. For example, the WTRU may be configured to use PUCCH on SCell for HARQ feedback / aperiodic CSI reporting if the DCI is received during a transition period from one monitoring pattern to another. The WTRU may use PUCCH on PCell during the transition period. The WTRU may use the PUCCH cell that was last used before the transition period (e.g., PUCCH on SCell or PCell).

[0101] The WTRU can switch control channel monitoring based on radio link monitoring. In one embodiment, the WTRU may monitor one or more WTRU-specific control channels on the SCell and not monitor one or more WTRU-specific control channels on the PCell. The WTRU can determine the channel quality on the SCell and, if certain conditions are met, switch to monitoring a WTRU-specific set of search spaces on the PCell. In one embodiment, the WTRU may monitor the control channels on the SCell and not monitor any control channels on the PCell, including common search spaces. The WTRU can determine the channel quality on the SCell and, if certain conditions are met, switch to monitoring control channels on the PCell.

[0102] The WTRU can determine whether to monitor a control channel on the PCell. Figure 5 shows a method for switching control channels (500). In one embodiment, the WTRU may be configured with one or more sets of search spaces on the PCell that can be monitored under certain conditions. The WTRU may monitor the configured sets of search spaces on the PCell in response to an event occurring (510).

[0103] The WTRU can begin monitoring a configured set of search spaces on a PCell if it does not receive a DCI on the SCell scheduling downlink and / or uplink data for a PCell or SCell within a set time. For example, the WTRU may be configured with a timer that can be reset when a DCI scheduling data on a PCell or SCell is received. If no DCI is received and the timer expires, the WTRU can begin monitoring one of the configured set of search spaces on the PCell. For example, the WTRU can monitor a configured set of search spaces on a PCell if it does not receive an uplink grant after sending a scheduling request (SR) or buffer status report (BSR). The WTRU can start a timer after sending an SR or BSR. If the timer expires and no UL grant is received, the WTRU can begin monitoring a configured set of search spaces on the PCell.

[0104] The WTRU can begin monitoring the configured search space set on the PCell if no downlink HARQ feedback instruction (DFI) is present for uplink transmission. For example, the WTRU can monitor for HARQ DFIs in the search space set within the SCell. If the WTRU fails to detect HARQ DFIs, it can begin monitoring the configured search space set on the PCell.

[0105] The WTRU can begin monitoring a configured search space set on the PCell if a measured value of the downlink reference signal falls below a set threshold for a set period of time. Such reference signals may reside on the PCell and / or SCell and may be composed of higher layers. For example, the WTRU can measure a downlink reference signal, and if the RSRP or detected energy falls below a set threshold, the WTRU can increment a counter. When the counter reaches a set value, the WTRU can begin monitoring a configured search space set on the PCell. The WTRU can reset the counter if at least one of the measured RSRP or detected energy exceeds a set threshold. The downlink reference signal may be one or more of the following: DMRS, CSI RS, SSB, or Positioning Reference Signal (PRS) for the control channel / data channel.

[0106] The WTRU can begin monitoring a configured set of search spaces on the PCell if a common signal is present or absent on the SCell. For example, the WTRU may be configured with a common search space set on the SCell to monitor, for instance, slot format instructions, preemption instructions, cancellation instructions, or new instructions for this purpose (e.g., using a new DCI format). If the WTRU does not detect any common control messages within a set period, it may switch to monitoring a configured set of search spaces on the PCell.

[0107] A WTRU can send instructions to a gNB to indicate a preference for PDCCH monitoring on different serving cells for scheduling PCells. A WTRU can await permission from the gNB to change control channels. A WTRU can send an instruction and immediately switch to monitoring the desired control channel. A WTRU can send an instruction, wait for a certain period of time or for a certain event, and then switch to monitoring the desired control channel. For example, a WTRU may switch at the end of a certain period of time, or upon receipt of an acknowledgment, or upon receipt of a DCI instruction from the gNB. This period of time or event may depend on the priority of the expected type of search space / service to be scheduled.

[0108] The WTRU may transmit instructions to the gNB to indicate (520) a request or preference for PDCCH monitoring on a different serving cell for scheduling a PCell, a radio link problem on the cell scheduling the PCell, and / or notification that the WTRU has switched PDCCH monitoring for scheduling the PCell to a different cell (and possibly the PCell itself). Such instructions may be provided by the WTRU by some of the methods described herein.

[0109] A WTRU can provide instructions by sending a scheduling request (SR). A WTRU may trigger a new SR and send that SR to the gNB to provide instructions. Such triggered SRs may be sent by the WTRU with a subset of PUCCH resources and / or a specific SR configuration. The RRC can configure the WTRU with the SR configuration that the WTRU may use and select when sending an SR for this purpose.

[0110] A WTRU can provide instructions by transmitting instructions or uplink control information (UCI) over the uplink channel. To provide instructions, the WTRU may include UCI in either PUCCH or PUSCH. The number of bits may be 1 (i.e., used only if the WTRU prefers to fall back to PDCCH monitoring on the PCell), or it may be proportional to the number of SCells applicable to scheduling the PCell (e.g., log2(number of cells that can schedule the PCell)).

[0111] A WTRU may provide instructions by transmitting or by including a MAC CE in a PUSCH. A WTRU may provide instructions that may include a SCell index experiencing a radio link problem by triggering a new MAC CE. If a WTRU does not have available PUSCH resources to transmit such a MAC CE, it may trigger a new SR. Such MAC CEs may be restricted to transmission on a subset of grant types and / or a subset of serving cells (e.g., PCell). Such restrictions may allow a WTRU to trigger an SR even if it has grants that do not meet the grant compliance criteria. Such SRs may be transmitted on a subset of PUSCH resources and / or a specific SR configuration. The RRC may configure a WTRU with an SR configuration that may be used and selected by the WTRU when transmitting an SR for this purpose.

[0112] A WTRU can provide instructions by sending a PRACH. A WTRU can provide instructions by initiating a new random access (RA) procedure and sending a preamble to the gNB. Such a preamble may be sent by the WTRU on a subset of PRACH resources and may be a preferred RACH procedure. The RRC can configure a WTRU with PRACH resources (e.g., a subset of preambles and / or RACH opportunities) that can be used and selected by the WTRU when sending msg1 or msgA for this purpose.

[0113] WTRUs can provide instructions by transmitting SRS. Transmissions may occur on a configured subset of resources.

[0114] The WTRU may monitor acknowledgments from the gNB before switching to monitor the control channel in the PCell (530). In one embodiment, the WTRU may monitor acknowledgments from the gNB while switching to monitor the control channel in the PCell or after switching. The WTRU may receive an affirmative or negative acknowledgment of a switch request (540). If the gNB sends a negative command and / or the gNB does not respond for a set period of time, the WTRU may switch back to monitor the control channel on the SCell (550). If the WTRU receives an affirmative acknowledgment of a switch request, the WTRU may switch to the requested cell or (if it has already switched) continue monitoring on the requested cell.

[0115] A WTRU may be configured to receive one or more DCIs that carry explicit confirmation of a switching request. A DCI may carry a bit field having a value indicating an affirmative confirmation and another value indicating a negative confirmation. Such DCIs may be in a new format or may be reused from an existing format.

[0116] A WTRU can receive one or more DCIs scheduling DL or UL data as confirmation of a switchover request. For example, a WTRU can send a switchover request and begin monitoring both the PCell and SCell. If a WTRU receives DL or UL scheduling on the PCell using the control channel on the PCell, the WTRU can interpret the scheduling as confirmation of the switchover request and stop monitoring the control channel on the SCell. In one example, a WTRU can receive a DL scheduling DCI or a UL scheduling DCI using the control channel on the SCell. The WTRU can interpret the scheduling as an instruction to stop the control channel switchover, and the WTRU can continue monitoring the control channel on the SCell.

[0117] A WTRU may be configured to receive a trigger for an aperiodic CSI report as confirmation of a switch request after a set period of time has passed since the request for a control channel switch. For example, a WTRU may receive an aperiodic CSI report request after sending a control channel switch request. The WTRU can stop monitoring the control channel on the PCell and continue monitoring the SCell for the control channel. The WTRU can continue monitoring the control channel on both cells (i.e., SCell and PCell) until the WTRU receives instructions from the gNB to change its configuration. This may allow the network to receive the channel quality of the SCell before reconfiguring the downlink control channel.

[0118] A WTRU may be configured to receive SCell activation or deactivation commands as confirmation of a switching request. For example, a WTRU may receive a DCI or MAC CE that deactivates a SCell after a configured period of time for sending a control channel switching request. The SCell deactivation command may be interpreted as confirmation to monitor only the control channel on the PCell. For example, a WTRU may receive a DCI or MAC CE that activates a SCell even if the SCell may already be activated. In this case, the activation command may be interpreted as a negative confirmation of a control channel switching request.

[0119] The active BWP of a scheduling cell and the cell being scheduled may have the same subcarrier interval. The maximum number of PDDCH candidates that a WTRU can process during a time slot, symbol set, or duration may be referred to as the maximum number of PDCCH candidates. The maximum number of non-overlapping CCEs that a WTRU can process during a time slot, symbol set, or duration may be referred to as the maximum number of non-overlapping CCEs. The maximum number of PDCCH candidates or the maximum number of non-overlapping CCEs may be determined based on WTRU capabilities or may be predefined in the specification.

[0120] In one embodiment, the WTRU can support a maximum number of PDCCH candidates or non-overlapping CCEs for each scheduled cell, and this maximum number of PDCCH candidates or non-overlapping CCEs can be divided or distributed across the scheduling cells of the scheduled cell. For example, if a PCell is scheduled by both a PCell and a SCell, the maximum number of PDCCH candidates or non-overlapping CCEs can be divided or distributed across the PCell and the SCell.

[0121] Figure 6 shows an exemplary method for monitoring PDCCH candidates for PCell and SCell in order to schedule PCells. The WTRU may determine the duration for the PDCCH candidate budget for a set of symbols based on the subcarrier interval associated with the PCell and the subcarrier interval associated with the SCell (610). The WTRU may determine the maximum number of PDCCH candidates to allocate to the PCell and SCell search space monitoring opportunities (620). The maximum number of PDCCH candidates is based on the cell-to-cell ratio. The WTRU may allocate the PDCCH candidates for the PCell and SCell search space monitoring opportunities based on the determined maximum number of PDCCH candidates (630). The WTRU may decode the allocated PDCCH candidates (640).

[0122] In one embodiment, the maximum number of PDCCH candidates or non-overlapping CCEs can be equally distributed across the scheduling cells (i.e., PCell and SCell) of the scheduling cell (i.e., PCell). The WTRU may support a maximum number (M) of PDCCH candidates and a maximum number (C) of non-overlapping CCEs for scheduling on PCell. If the WTRU is configured with SCell and PCell for scheduling on PCell, the WTRU may assume a maximum of M / 2 PDCCH candidates and a maximum of C / 2 non-overlapping CCEs on PCell, and a maximum of M / 2 PDCCH candidates and a maximum of C / 2 non-overlapping CCEs on SCell.

[0123] In one embodiment, the WTRU may consist of a portion or proportion of the maximum number of PDCCH candidates or the maximum number of non-overlapping CCEs that should be assumed for each scheduling cell of the scheduled cells, for example using RRC signaling. The WTRU may be configured to determine the proportion of the maximum number of PDCCH candidates or non-overlapping CCEs assumed for each scheduling cell of the scheduled cells, based on the monitoring configuration of the search space set. At the start of a set of slots or symbols, the WTRU may exclude scheduling cells in the set of slots or symbols for the scheduled cells that do not have a search space monitoring opportunity.

[0124] For example, a WTRU may consist of a first search space monitoring pattern within the PCell and a second search space monitoring pattern within the SCell for PCell scheduling. At the start of a set of slots or symbols, the WTRU may determine that the PCell has no monitoring opportunities within the set of slots or symbols for PCell scheduling, and that the maximum number of PDCCH candidates or non-overlapping CCEs are all within the SCell. The WTRU may use an RRC configuration of the set of search spaces monitoring scheduling on the PCell to determine the maximum number of PDCCH candidates for scheduling.

[0125] WTRU can assume that while RRC is idle or in an inactive mode or state, the maximum number of PDCCH candidates or non-overlapping CCEs per scheduled cell is equally distributed across the scheduling cells.

[0126] The active BWP of a scheduling cell and the cell being scheduled may have different subcarrier intervals. When the cell being scheduled and the scheduling cell have different subcarrier intervals, the maximum number of PDDCH candidates and the maximum number of non-overlapping CCEs that the WTRU can process may be defined over the duration. Such a duration may be the smallest time slot of the different subcarrier intervals (i.e., the time slot of the highest subcarrier interval). For example, if the WTRU consists of subcarrier intervals of 15 kHz, 30 kHz, and 60 kHz, the duration may be the time slot of the 60 kHz subcarrier interval.

[0127] In one embodiment, the maximum number of PDCCH candidates or non-overlapping CCEs per scheduled cell can be equally distributed across the scheduling cells of the scheduled cells for each duration. The maximum number of PDCCH candidates or non-overlapping CCEs can be distributed across the scheduling cells of the scheduled cells based on the subcarrier interval of the scheduling cell. In one example, a lower subcarrier interval may be configured with a lower maximum number of PDCCH candidates or non-overlapping CCEs per duration, while in another example, a lower subcarrier interval may be configured with a higher maximum number of PDCCH candidates or non-overlapping CCEs per duration.

[0128] Figure 7 shows the maximum number (M) of PDCCH blind decoder (BD) candidates and the maximum number (C) of non-overlapping CCEs for PCell scheduling. In Figure 7, Mx,i represents the maximum number of PDCCH candidates, where x=1 represents a PCell, x=2 represents an SCell, and i represents the duration. As shown in Figure 7, a PCell consists of 15kHz subcarrier intervals and is composed of M1,1>M2,1 and C1,1>C2,1 per first duration. The maximum number of PDCCH candidates for scheduling on a PCell per duration is M=M1,1+M2,1=M2,2. The maximum number of non-overlapping CCE candidates for scheduling on a PCell per duration is C=C1,1+C2,1=C2,2.

[0129] In one embodiment, the maximum number of PDCCH candidates (M) or the maximum number of non-overlapping CCEs (C) per scheduled cell can be distributed across the scheduling cells of the scheduled cell based on the time slot number or subframe number of the scheduling cell (i.e., M may be a function of time slot M(t) and C may be a function of time slot C(t)). The maximum number of PDCCH candidates or non-overlapping CCEs may be higher in some time slots or subframes and lower in some time slots or subframes. For example, in Figure 7, SCell and PCell are scheduling cells for PCell, where SCell is configured with a 30KHz subcarrier interval and PCell is configured with a 15KHz subcarrier interval. In the first time slot of SCell, the maximum number of PDCCH candidates is M2,1 and the maximum number of non-overlapping CCEs is C2,1. In the second time slot of SCell, the maximum number of PDCCH candidates is M2,2, and the maximum number of non-overlapping CCEs is C2,2, where M2,2 > M2,1 and C2,2 > C2,1.

[0130] In one embodiment, the WTRU may be configured using a PCell and a SCell to schedule PDSCH / PUSCH on a PCell. The WTRU can dynamically determine the maximum number of PDCCH candidates and / or non-overlapping CCEs for each scheduling cell. In Figure 8, there are eight durations (i). At the start of duration i, the WTRU can determine the maximum number of PDCCH candidates on the PCell for PCell scheduling, M1,i, and the maximum number of PDCCH candidates on the SCell for PCell scheduling, M2,i.

[0131] WTRU can distribute or allocate the maximum number of PDCCH candidates or non-overlapping CCEs per scheduled cell across the scheduling cells of the scheduled cells. Distribution or allocation may refer to the processing capacity for the scheduling cells, or how many PDCCH candidates can be processed per slot. The maximum number of PDCCH candidates or non-overlapping CCEs may be based on the configured PDCCH candidates.

[0132] In one embodiment, the WTRU may decide to allocate a portion or percentage (i.e., less than the maximum) of the number of PDCCH candidates or non-overlapping CCEs per scheduled cell to the scheduling cells. At the start of a duration or time slot or set of symbols, the WTRU may determine a portion of the maximum number of PDCCH candidates or non-overlapping CCEs for the scheduling cells based on the number of configured PDCCH candidates or non-overlapping CCEs on the search space set on the scheduling cells relative to the total number of configured PDCCH / non-overlapping CCEs for the scheduling cells. For example, the WTRU may be configured using a PCell and a SCell to schedule PDSCH / PUSCH on a PCell. At the start of the duration, the WTRU may consist of N1 PDCCH candidates on the PCell for PCell scheduling and N2 PDCCH candidates on the SCell for PCell scheduling. WTRU can determine that a portion or proportion of the maximum number of PDCCH candidates for PCell scheduling on a PCell is equal to N1 / (N1+N2), and a portion or proportion of the maximum number of PDCCH candidates for PCell scheduling on a SCell is equal to N2 / (N1+N2). WTRU can assume that the maximum number of PDCCH candidates per set of duration / time slot / symbol is MxN2 / (N1+N2) on a PCell and MxN1 / (N1+N2) on a SCell, where M is the maximum number of PDCCH candidates for PCell scheduling using all scheduling cells. WTRU does not need to monitor the remaining N1-M×N1 / (N1+N2) candidates on a PCell and the remaining N2-M×N2 / (N1+N2) candidates on a SCell. Similarly, with respect to the number of non-overlapping CCEs, WTRU can assume a maximum number of non-overlapping CCEs of CxK1 / (K1+K2) on PCell and CxK1 / (K1+K2) on SCell, where C is the maximum number of non-overlapping CCEs for PCell scheduling using all scheduling cells, and K1 and K2 are the configured number of non-overlapping CCEs per PCell and SCell, respectively.

[0133] In one embodiment, the WTRU can be configured to determine a portion or percentage of the maximum number of PDCCH candidates or non-overlapping CCEs for a scheduling cell based on the frequency bandwidth configured for the CORESET on the scheduling cell to schedule on the scheduling cell, across the total frequency bandwidth configured for all CORESETs on different scheduling cells to schedule on the scheduling cell. In one embodiment, the WTRU can determine a portion or percentage of the maximum number of PDCCH candidates or non-overlapping CCEs for a scheduling cell based on the frequency bandwidth of the active bandwidth portion of the scheduling cell across the total frequency bandwidth of the active bandwidth portion configured to schedule on the scheduling cell.

[0134] In one embodiment, the WTRU can be assumed to be that the maximum number of PDCCH candidates or non-overlapping CCEs for a scheduling cell per set of duration, time slot, or symbol is equal to the number of PDCCH candidates / non-overlapping CCEs configured on the search space set on the scheduling cell per set of duration / time slot / symbol. For example, the WTRU may be configured using a PCell and a SCell to schedule PDSCH / PUSCH on a PCell. The WTRU may be configured using a search space set on a PCell having N1 PDCCH candidates and K1 non-overlapping CCEs for scheduling on a PCell. The WTRU may be configured using a search space set on a SCell having N2 PDCCH candidates and K2 non-overlapping CCEs for scheduling on a PCell. The WTRU can be assumed to be that the maximum number of PDCCH candidates is equal to N2 on the SCell and M-N2 on the PCell for each set of duration / time slot / symbol, where M is the maximum number of PDCCH candidates for PCell scheduling using all scheduling cells. The UE does not have to drop or monitor N1-(M-N2) PDCCH candidates on the PCell. For non-overlapping CCEs, the WTRU can assume that the maximum number of non-overlapping CCEs is equal to K2 on the SCell and C-K2 on the PCell for each set of duration / time slot / symbol, where C is the maximum number of non-overlapping CCEs for PCell scheduling using all scheduling cells.

[0135] In one embodiment, for a scheduled cell, the WTRU may consist of a set of search spaces having a total number of PDCCH candidates / non-overlapping CCEs that exceeds the maximum number of PDDCH candidates / non-overlapping CCEs per scheduled cell. The WTRU can prioritize the configured PDCCH candidates / non-overlapping CCEs and / or search spaces, and can monitor only a subset of the configured PDCCH candidates / non-overlapping CCEs and / or search spaces. In one embodiment, the WTRU can prioritize search spaces on different scheduled cells for a scheduled cell. At the start of a time slot / set of symbols / duration, the WTRU can prioritize search spaces by at least search space priority or search space index.

[0136] Figures 9 and 10 show examples of search space prioritization based on search space priority and search space index, respectively.

[0137] In one embodiment, the WTRU can prioritize search spaces based on search space priority. A set of search spaces configured across different scheduling cells for scheduling cells may be configured using priority parameters. For example, for scheduling on PCell, a set of search spaces may be configured on PCell and SCell, and each search space may be associated with a priority. At the start of a time slot / symbol set / duration, the WTRU can select search spaces in order of priority (e.g., ascending priority) until it reaches the maximum number of PDCCH candidates / number of non-overlapping CCEs per time slot / symbol set / duration. The WTRU can monitor the selected search spaces. As shown in Figure 9, the order or monitors (p1, p2, p3, and p4) are PCell search space 0, PCell search space 1, SCell search space 0, and SCell search space 1.

[0138] In one embodiment, the WTRU can prioritize search spaces based on the search space index, as shown in Figure 10. For scheduling on PCell, the set of search spaces may consist of PCell and SCell. At the start of a time slot / symbol set / duration, the WTRU can select PCell search spaces in ascending order of search space index. After selecting all search spaces within PCell and not reaching the maximum number of PDCCH candidates / non-overlapping CCEs, the WTRU can select SCell search spaces in ascending order of search space index until it reaches the maximum number of PDCCH candidates / non-overlapping CCEs per time slot / symbol set / duration. The WTRU can monitor the selected search spaces. As shown in Figure 10, the order or monitors (p1, p2, p3, and p4) are PCell search space 0, SCell search space 0, PCell search space 1, and SCell search space 1.

[0139] In one embodiment, at the start of a time slot / symbol set / duration, the WTRU may select a search space with a lower search space index from the PCell and a search space with a lower search space index from the SCell. If the maximum number of PDCCH candidates / non-overlapping CCEs has not been reached, the WTRU may select the next search space index from the PCell and the next search space index from the SCell.

[0140] For example, a WTRU may consist of two search spaces on a PCell (i.e., search space 0 and search space 1) and two search spaces on an SCell (i.e., search space 0 and search space 1). The WTRU can select search space 0 on the PCell, and if the maximum number of PDCCH candidates / non-overlapping CCEs has not been reached, the WTRU can select search space 0 on the SCell. If the maximum number of PDCCH candidates / non-overlapping CCEs has not been reached, the WTRU can select search space 1 on the PCell. If the maximum number of PDCCH candidates / non-overlapping CCEs has not been reached, the UE can select search space 1 on the SCell (as shown in Figure 5B, p1 / p2 / p3 / p4 are the priority levels for monitoring the search spaces).

[0141] Since there are several remaining PDCCH candidates / non-overlapping CCEs that WTRU can process, if the search space is selected to be monitored, WTRU may drop or not monitor some PDCCH candidates / CCEs in the search space, but the overall number of PDCCH candidates / CCEs configured for that search space will result in exceeding the maximum number of PDCCH candidates / non-overlapping CCEs per slot / set of symbols / duration.

[0142] The WTRU may drop or not monitor PDCCH candidates at a certain aggregation level (AL). For example, the WTRU may be configured not to monitor higher aggregation levels such as AL=16 and AL=8. In one example, the WTRU may be configured not to monitor lower aggregation levels such as AL=1, AL=2, and AL=4. In one example, the WTRU may be configured to choose to monitor CCEs with lower indices if the configured CCEs for the search space could result in a number exceeding the maximum number of PDCCH candidates / number of non-overlapping CCEs.

[0143] While features and elements are described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. Furthermore, the methods described herein can be implemented in computer programs, software, or firmware embedded in computer-readable media for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor associated with software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU) comprising a processor and memory, wherein the processor and memory are A radio resource control (RRC) message is received, and the RRC message includes control information indicating that a transmission performed using a primary cell (PCell) can be scheduled via the PCell or a secondary cell (SCell), and the RRC message includes first search space configuration information associated with the PCell and second search space configuration information associated with the SCell. Determine the maximum number of candidate physical downlink control channels (PDCCHs) to monitor within a slot for scheduling the transmission performed using the PCell. Determine the maximum number of non-overlapping control channel elements (CCEs) to monitor within the slot for scheduling the transmission performed using the PCell, It is determined that for the first slot, a first ratio of the maximum number of PDCCH candidates can be applied to PDCCH monitoring in PCell, and for the first slot, a second ratio of the maximum number of PDCCH candidates can be applied to PDCCH monitoring in SCell. It is determined that for the first slot, the first ratio of the maximum number of non-overlapping CCEs can be applied to PDCCH monitoring in PCell, and for the first slot, the second ratio of the maximum number of non-overlapping CCEs can be applied to PDCCH monitoring in SCell. The first PDCCH transmission is decoded via the SCell, and the first PDCCH transmission is decoded via the SCell, which schedules the first physical downlink shared channel (PDSCH) transmission received via the PCell. Upon receiving a media access control (MAC) control element (CE) indicating the deactivation of the aforementioned SCell, Based on the fact that SCell is deactivated in the second slot for scheduling the transmission which is performed using PCell, it is determined that the maximum number of PDCCH candidates is applicable to PDCCH monitoring in PCell for the second slot. Based on the fact that the SCell is deactivated in the second slot, it is determined that the maximum number of non-overlapping CCEs can be applied to PDCCH monitoring in the PCell for the second slot. The second PDCCH transmission is decoded via the PCell, and the second PDCCH transmission is decoded via the PCell which schedules the second PDSCH transmission received via the PCell. It receives downlink control information (DCI) which includes a bit field indicating which cell to use for physical uplink control channel (PUCCH) transmission. WTRU was configured in this way.

2. The aforementioned processor and memory are The PCell is monitored using the first ratio of the maximum number of PDCCH candidates applicable to PDCCH monitoring in the PCell, The SCell is monitored using the second ratio of the maximum number of PDCCH candidates applicable to PDCCH monitoring in the SCell. The WTRU according to claim 1, configured as described above.

3. The aforementioned processor and memory are Send a Hybrid Automated Resend Request (HARQ) Acknowledgment (ACK) or Negative Response (NACK) feedback report. The WTRU according to claim 1, configured as described above.

4. The aforementioned processor and memory are Reserve or allocate a set of search space indices for a scheduled cell on a scheduled cell. The WTRU according to claim 1, further configured as follows.

5. The WTRU according to claim 1, wherein the configuration information indicates the first ratio of the maximum number of PDCCH candidates applicable to PDCCH monitoring in the PCell.

6. The WTRU according to claim 5, wherein the configuration information indicates that the first ratio of the maximum number of non-overlapping CCEs is applicable to PDCCH monitoring in the PCell.

7. The aforementioned processor and memory are The search space is selected in order of priority until the maximum number of non-duplicate CCEs is reached. The WTRU according to claim 1, further configured as follows.

8. A method carried out by a wireless transmit / receive unit (WTRU), wherein the method is: Receiving a Radio Resource Control (RRC) message, wherein the RRC message includes control information indicating that a transmission performed using a primary cell (PCell) can be scheduled via the PCell or a secondary cell (SCell), and the RRC message includes first search space configuration information associated with the PCell and second search space configuration information associated with the SCell. To determine the maximum number of candidate physical downlink control channels (PDCCHs) to monitor within a slot for scheduling the transmission performed using the PCell, Determining the maximum number of non-overlapping control channel elements (CCEs) to monitor within the slot for scheduling the transmission performed using the PCell, It is determined that for the first slot, a first ratio of the maximum number of PDCCH candidates can be applied to PDCCH monitoring in PCell, and a second ratio of the maximum number of PDCCH candidates can be applied to PDCCH monitoring in SCell for the first slot, It is determined that for the first slot, the first ratio of the maximum number of non-overlapping CCEs can be applied to PDCCH monitoring in PCell, and for the first slot, the second ratio of the maximum number of non-overlapping CCEs can be applied to PDCCH monitoring in SCell, The first PDCCH transmission is decoded via the SCell, wherein the first PDCCH transmission is decoded via the SCell which schedules a first physical downlink shared channel (PDSCH) transmission received via the PCell. Receiving a media access control (MAC) control element (CE) indicating the deactivation of the aforementioned SCell, Based on the fact that SCell is deactivated in the second slot for scheduling the transmission which is performed using PCell, it is determined that the maximum number of PDCCH candidates is applicable to PDCCH monitoring in PCell for the second slot, Based on the fact that the SCell is deactivated in the second slot, it is determined that the maximum number of non-overlapping CCEs can be applied to PDCCH monitoring in the PCell for the second slot, The method involves decoding a second PDCCH transmission via the PCell, wherein the second PDCCH transmission is decoded via the PCell which schedules a second PDSCH transmission received via the PCell. Receiving Downlink Control Information (DCI) which includes a bit field indicating which cell to use for physical uplink control channel (PUCCH) transmission, Methods that include...

9. The PCell is monitored using the first ratio of the maximum number of PDCCH candidates applicable to PDCCH monitoring in the PCell, Monitoring the SCell using the second ratio of the maximum number of PDCCH candidates applicable to PDCCH monitoring in the SCell, The method according to claim 8, further comprising:

10. Sending a Hybrid Automated Resend Request (HARQ) Acknowledgment (ACK) or Negative Response (NACK) Feedback Report, The method according to claim 8, further comprising:

11. Reserving or allocating a set of search space indices for a scheduled cell on a scheduled cell, The method according to claim 8, further comprising:

12. The method according to claim 8, wherein the configuration information indicates the first ratio of the maximum number of PDCCH candidates applicable to PDCCH monitoring in PCell.

13. The method according to claim 12, wherein the configuration information indicates that the first ratio of the maximum number of non-overlapping CCEs is applicable to PDCCH monitoring in the PCell.

14. Select the search space in order of priority until the maximum number of non-duplicate CCEs is reached. The method according to claim 8, further comprising:

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