Method and device 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 August 5, 2020, U.S. Provisional Patent Application No. 63 / 168,080, filed March 30, 2021, and U.S. Provisional Patent Application No. 63 / 185,878, filed May 7, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] The New Radio (NR) technology, defined by 3GPP, is designed to provide high flexibility for both control and data channels. For control channels, NR supports different monitoring patterns and different physical downlink control channel (PDCCH) locations within a slot. For data channels, NR supports variable transmission durations, starting symbols within a slot, and flexible hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback timing. Using the concept of bandwidth portions, carriers can support wireless transmit receive units (WTRUs) with different bandwidth capabilities, such as narrowband and wideband devices. Additionally, different carrier spacings can be used simultaneously on the same carrier. For example, a large bandwidth portion can be configured with a large subcarrier spacing (SCS), while a small bandwidth portion is configured with a smaller SCS, allowing different WTRUs with different capabilities to coexist on the same spectrum.

[0003] NR is proposed to share spectrum with Long Term Evolution (LTE). Sharing spectrum with LTE requires semi-static reservation of physical resources at least for the LTE control region. This may reduce the NR primary cell (PCell) capacity transmitting downlink control signaling and may also reduce the available resources for data in a slot because the control region should precede the data region. Supporting NR secondary cell (SCell) scheduling for the NR PCell would result in reliability issues for downlink control information. Also, by supporting the control channel on the SCell scheduling data on the PCell, the WTRU may not be able to simultaneously receive or monitor the control channels on both cells, resulting in increased blind decoding effort. Therefore, a method is needed for NR to efficiently share spectrum with LTE. Summary of the Invention

[0004] A wireless transmit / receive unit (WTRU) may be configured to monitor physical downlink control channel (PDCCH) candidates for a primary cell (PCell) and a secondary cell (SCell). The WTRU may be configured to determine a duration for a PDCCH candidate budget for a set of symbols based on a subcarrier spacing associated with the PCell and a subcarrier spacing associated with the SCell. The WTRU may be configured to determine a maximum number of PDCCH candidates to allocate to search space monitoring opportunities for the PCell and search space monitoring opportunities for 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 search space monitoring opportunities for the PCell and search space monitoring opportunities for the SCell 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 set of symbols, and may be configured to determine the maximum number of PDCCH candidates to allocate, provided there are overlapping search space monitoring opportunities. The per-cell ratio may be determined based on the number of configured PDCCH candidates on the PCell (N1) and the number of configured downlink control channel candidates on the SCell (N2). The maximum number of PDCCH candidates for the PCell may be based on the number of configured PDCCH candidates for the PCell (N1) as a percentage of the total number of configured PDCCH candidates for the PCell and SCell (N1+N2). The maximum number of PDCCH candidates for the SCell may be based on the number of configured PDCCH candidates for the SCell (N2) as a percentage of the total number of configured PDCCH candidates for the 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 drawings]

[0006] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which like reference numerals indicate similar elements and in which: [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram illustrating an exemplary wireless transmit / receive unit (WTRU) that may be used within the communications system shown in FIG. 1A, according to one embodiment. [Figure 1C] 1B is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 1D] 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 2] 1 illustrates an exemplary method for switching between monitoring patterns. [Figure 3] 1 illustrates an exemplary method for switching between monitoring patterns. [Figure 4] 1 illustrates an example of a WTRU switching between a first monitoring pattern, a transition time, and a second monitoring pattern. [Figure 5] 1 illustrates an exemplary method for control channel switching. [Figure 6] 1 illustrates an exemplary method for monitoring PDCCH candidates for a PCell and an SCell for scheduling a PCell. [Figure 7] FIG. 10 is a diagram illustrating the maximum number of PDCCH BDs / non-overlapping CCEs for PCell scheduling. [Figure 8] 10 is an example illustrating dynamic determination of maximum PDCCH candidates per scheduling cell. [Figure 9] 10 illustrates an exemplary search space prioritization using search space priorities. [Figure 10] 1 illustrates an exemplary search space prioritization using a search space index. DETAILED DESCRIPTION OF THE INVENTION

[0007] 1A illustrates an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. Communication system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communication system 100 may 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 filtered OFDM, filter bank multicarrier (FBMC), etc.

[0008] 1A, communications system 100 may include wireless 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, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a station (STA), may be configured to transmit and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a mobile phone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and application (e.g., remote surgery), an industrial device and application (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), a consumer electronic device, a device operating in a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

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

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

[0011] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0012] More specifically, as noted above, the communications system 100 may be a multiple-access system and may use one or more channel access schemes, such as, for example, CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a of the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the 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 (DL) Packet Access (HSDPA) and / or High-Speed Uplink (UL) Packet Access (HSUPA).

[0013] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the 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 the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using NR.

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

[0016] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity, WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access, WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0017] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a local area such as a location such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 through the CN 106.

[0018] The RAN 104 may communicate with the CN 106, which may be any type of network configured to provide voice, data, application, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as different throughput, latency, error tolerance, reliability, data throughput, mobility, etc. The CN 106 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in FIG. 1A , it will be understood that the RAN 104 and / or CN 106 may communicate directly or indirectly with other RANs that use the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may utilize NR radio technology, the CN 106 may also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0019] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a public switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP Internet protocol suite. The networks 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, which may use the same RAT as the RAN 104 or a different RAT.

[0020] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links.) For example, the WTRU 102c 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 an IEEE 802 wireless technology.

[0021] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0022] The processor 118 may be a general-purpose processor, a special-purpose 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 the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the 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) over 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 IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0024] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may use MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0025] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, 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 WTRU 102 may be coupled to and may receive user-entered data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Furthermore, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. 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, etc. In other embodiments, the processor 118 may access information and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0027] The processor 118 may receive power from the power source 134, but may be configured to distribute and / or control the power to other components in the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, 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) regarding the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may obtain location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0029] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or 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, etc. The peripherals 138 may include one or more sensors. The sensor may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor, and the like.

[0030] The WTRU 102 may include a full-duplex radio for transmitting and receiving some or all of the signals (e.g., associated with a particular subframe on both the UL (e.g., for transmission) and DL (e.g., for reception)) simultaneously and / or together. The full-duplex radio may include an interference management unit for reducing and or substantially eliminating self-interference through hardware (e.g., chokes) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for transmitting and receiving some or all of the signals (e.g., associated with a particular subframe on either the UL (e.g., for transmission) or DL (e.g., for reception)).

[0031] 1C is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As mentioned above, the RAN 104 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using E-UTRA radio technology. The RAN 104 may also communicate with the CN 106.

[0032] The RAN 104 may include eNodeBs 160a, 160b, and 160c, although it will be understood that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In an embodiment, the eNodeBs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNodeB 160a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0033] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling, etc. in the UL and / or DL. As shown in FIG. 1C, the eNodeBs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0034] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although the foregoing elements are shown as part of the CN 106, it will be understood that any of these elements may also be owned and / or operated by an entity other than the CN operator.

[0035] The MME 162 may be connected to each of the eNodeBs 162a, 162b, 162c in the RAN 104 via an S1 interface and may function as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies such as GSM and / or WCDMA.

[0036] The SGW 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-eNode-B handovers, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0037] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0038] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional landline communications devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. Furthermore, the CN 106 may provide the WTRUs 102a, 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.

[0039] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments, such a terminal may use a wired communication interface (e.g., temporarily or permanently) with the communication network.

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

[0041] A WLAN in infrastructure Basic Service Set (BSS) mode may have an access point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or interface with a distribution system (DS) or another type of wired / wireless network that carries traffic within and / or outside the BSS. Traffic originating from outside the BSS to a STA may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP and transmitted to the respective destination. Traffic between STAs within the BSS may be transmitted, for example, through the AP; the source STA may send traffic to the AP, which 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 (e.g., directly between them) in 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 an Independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as an "ad hoc" communication mode.

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

[0043] High Throughput (HT) STAs may use 40 MHz wide channels 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] A Very High Throughput (VHT) STA may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. The 40 MHz and / or 80 MHz wide channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data may pass through a segment parser that may split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing may be performed separately on each stream. The streams may be mapped to two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed and the combined data may be transmitted to the Medium Access Control (MAC).

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

[0046] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as a primary channel. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be configured and / or limited by the STAs among all STAs operating in the BSS that support the minimum bandwidth operating mode. In an 802.11ah example, the primary channel can be 1 MHz wide for STAs (e.g., MTC-type devices) that support (e.g., only) the 1 MHz mode, even if the AP and other STAs in the 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) configuration can depend on the condition of the primary channel. For example, if the primary channel is busy, a STA transmitting to the AP (that only supports 1 MHz mode of operation) may cause all of the available frequency bands to be considered busy, even if most of the available frequency bands are 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] 1D is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As mentioned above, the RAN 104 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using NR radio technology. The RAN 104 may also communicate with the CN 106.

[0049] The RAN 104 may include gNBs 180a, 180b, and 180c, although it will be understood that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to transmit and / or receive signals to the gNBs 180a, 180b, and 180c. Thus, the gNB 180a may, for example, transmit wireless signals to and / or receive wireless signals from the WTRU 102a using multiple antennas. In one embodiment, the gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, and the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0050] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., including varying numbers of OFDM symbols and / or varying lengths of absolute time).

[0051] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNodeBs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate with and connect to gNBs 180a, 180b, 180c while also communicating with and connecting to another RAN, such as eNodeBs 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeBs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, while the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

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

[0053] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While the foregoing elements are shown as part of the CN 106, it will be understood that any of these elements may also be owned and / or operated by an entity other than the CN operator.

[0054] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may function as a control node. For example, the AMF 182a, 182b may be responsible for user authentication of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selection of the SMF 183a, 183b for registration, management of registration areas, termination of non-access stratum (NAS) signaling, mobility management, etc. The network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service utilizing the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, etc. The AMFs 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0055] The SMFs 183a and 183b may be connected to the AMFs 182a and 182b in the CN 106 via an N11 interface. The SMFs 183a and 183b may also be connected to the UPFs 184a and 184b in the CN 106 via an N4 interface. The SMFs 183a and 183b may select and control the UPFs 184a and 184b and configure the routing of traffic through the UPFs 184a and 184b. The SMFs 183a and 183b may perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0056] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks such as the Internet 110 to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions such as packet routing and forwarding, user plane policy enforcement, support for multi-homed PDU sessions, handling user plane QoS, DL packet buffering, mobility anchoring, etc.

[0057] The CN 106 may facilitate communication with other networks. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. Furthermore, the CN 106 may provide the WTRUs 102a, 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, the WTRUs 102a, 102b, 102c may be connected to the local DNs 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0058] 1A-1D and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNodeBs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or simulate network and / or WTRU functions.

[0059] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or an 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 communication network to test other devices in the communication 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 communication network. The emulation devices may be directly coupled to another device for testing and / or conducting tests using over-the-air wireless communication.

[0060] One or more emulation devices may perform one or more functions, inclusive, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network 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 (which may include, e.g., one or more antennas) may be used by the emulation devices 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 (relies on cyclic prefix) Traditional OFDM CQI Channel Quality Indicator CRC Cyclic Redundancy Check CSI Channel State Information CW Contention Window CWS Contention Window Size CO 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 (e.g., Long Term Evolution) after 3GPP LTE R8 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 Radio 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 self-contained subframes) 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 provide higher data rates, much lower latency, and several new features compared to LTE. To enable a smooth transition from LTE to NR, spectrum sharing may be used to allow both radio access technologies (RATs) to share the same frequency resources. The spectrum sharing function 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 is expected that the number of NR WTRUs may exceed the number of LTE WTRUs, which motivates the need to redesign and extend the spectrum sharing function to enable a more efficient way to share spectrum between the networks of the two RATs.

[0063] A common deployment for NR is to have an LTE cell and an NR primary cell (PCell) sharing the same spectrum in the lower frequency region, and to provide an NR WTRU with a secondary cell (SCell) operating in the higher frequency region so that high data rates can be achieved.

[0064] A WTRU may be configured with control channels on both the PCell and the SCell that can schedule data in the PCell. Embodiments are presented herein regarding how a WTRU can monitor control channels across different cells to schedule data in the PCell. While the focus is on scheduling data on the PCell, the embodiments presented herein may also apply to other scenarios, such as a control channel on an SCell and a PCell scheduling data on the SCell, and a control channel on a different SCell scheduling data on the SCell.

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

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

[0067] In one embodiment, the WTRU may be configured to monitor the entire search space in the SCell for scheduling the PCell. This may result in WTRU reachability issues. For example, if radio conditions deteriorate on the SCell, the WTRU may not be reachable even if the PCell radio link is good.

[0068] In one embodiment, the WTRU may trigger monitoring of a configured search space on the PCell, which may be considered a fallback mechanism. For example, the 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 issue). In this embodiment, the WTRU may autonomously activate or start monitoring the search space. The WTRU may do so after, for example, measurements, the absence of DCI for a configured time period, or a number of PDCCH opportunities (e.g., ≧1) in a configured period.

[0069] In one embodiment, the WTRU may perform radio 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 send a switch indication to a network entity, e.g., a gNB. The indication may be, for example: a transmission on a specific or any PRACH resource, initiation of a RACH procedure, an SR transmission, a special resource for switch indication, an SRS transmission, or triggering or inclusion of a MAC CE to indicate the SCell RLM state of the SCell. The MAC CE may be restricted for transmission on the PCell.

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

[0071] The properties of the data contained in a transport block (TB) may refer to any parameters configuring the logical channel or radio bearer for which the data may be contained in the TB, such as at least one of the following: logical channel priority, prioritized bit rate, logical channel group, or RLC mode.

[0072] The properties of the grant or allocation may refer to the properties of the data contained in the corresponding TB. The indication by the DCI may include an explicit indication. The explicit indication may be, for example, by a DCI field or by an RNTI used to mask the CRC of the PDCCH. The indication by the DCI may include an implicit indication. The implicit indication may be, for example, by properties such as the DCI format, the DCI size, the control resource set (CORESET) or search space, the aggregation level, or the identity of the first control channel resource for the DCI (e.g., the index of the first CCE). The mapping between properties and values may be signaled, for example, by RRC or MAC.

[0073] In one embodiment, a WTRU may be configured with a control resource set (CORESET) and / or search space set that may be defined across a cell (i.e., the search space set and / or CORESET may have resources in both the PCell and the SCell). In one example, the CORESET may have interleaved resources having a first set of frequency resources in the PCell and a second set of frequency resources in the SCell. In one example, the search space may be configured within a CORESET that may have physical resources in both the PCell and the SCell. In one example, the search space set may be configured to have resources on two CORESETs in different cells (e.g., one CORESET on the PCell and another CORESET on the 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 the scheduling cell may include parameters indicating one or more scheduled target cells. For example, the RRC configuration of the search space may include a target cell ID as part of the search space configuration. A set of search space indices on the scheduling cell may be reserved or dedicated for scheduling on the scheduled cells. For example, a search space with ID=0 (or with an ID within a certain range or value) in the SCell may be reserved for scheduling on the PCell.

[0075] In one embodiment, the WTRU may use a control channel selection procedure. The control channel selection procedure may be used to determine a serving cell, a bandwidth portion (BWP), a search space, and / or a CORESET over which the PDCCH is monitored for reception of downlink control and / or scheduling information corresponding to a particular cell (e.g., a 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 reception of downlink control and / or scheduling information corresponding to a particular cell (e.g., PCell) based on at least one of the following: reception of WTRU common signaling, reception of WTRU-specific signaling, receiving a number of DL signals, activation of a particular DRX cycle, as a function of a DRX state or timer, as a function of a configured time domain pattern, upon activation or deactivation of the serving cell, upon activation of a BWP, upon detection of beam failure, upon declaration of a Radio Link Failure (RLF), or upon detection of a consistent UL LBT failure.

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

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

[0079] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on the serving cell, BWP, search space, and / or CORESET for reception of downlink control information and / or scheduling information corresponding to a particular cell based on reception of a number of 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 one example, the WTRU may switch, activate, or deactivate PDCCH monitoring if the number of DL signals is below or above a threshold during a particular time period.

[0080] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on the serving cell, BWP, search space, and / or CORESET for reception of downlink control information and / or scheduling information corresponding to a particular cell based on activation of the DRX cycle. After transitioning to a DRX cycle or a particular DRX cycle (e.g., short DRX or long DRX), the WTRU may switch, activate, or deactivate PDCCH monitoring on the serving cell, BWP, search space, and / or CORESET for reception of downlink control information and / or scheduling information for another serving cell. In one example, the WTRU may monitor the PDCCH on the PCell during the on duration of the long DRX cycle. Upon receiving DCI or scheduling information during the particular on duration or activating the short DRX cycle, the WTRU may activate PDCCH monitoring on the SCell for scheduling 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 for reception of downlink control information and / or scheduling information corresponding to a particular cell based on a function of the DRX state or timer. The WTRU may be configured or predefined to monitor the PDCCH for scheduling a PCell on a particular cell, search space, BWP, and / or CORESET depending on whether a DRX timer (e.g., a drx inactivity timer, a drx-HARQ RTT timer, a data inactivity timer, and / or a drx retransmission timer) is running. In one example, the WTRU may monitor an SCell for PCell scheduling if the drx inactivity timer is running.

[0082] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET for reception of downlink control information and / or scheduling information corresponding to a particular cell based on a function of a configured time-domain pattern. The WTRU may be configured with a pattern for monitoring the PDCCH for scheduling a PCell 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 the serving cell, BWP, search space, and / or CORESET for receiving downlink control information and / or scheduling information corresponding to a particular cell based on activation or deactivation of the serving cell. The WTRU may start or stop monitoring PDCCH resources associated with scheduling a particular cell upon activation or deactivation of the PDCCH resources (e.g., after receiving MAC CE deactivation or activation, or after expiration of an SCell deactivation timer). The WTRU may stop monitoring PDCCH resources associated with scheduling a PCell if the cell on which the PDCCH resources reside is deactivated. The WTRU may start monitoring the PDCCH on a different SCell for scheduling the PCell or the PCell itself.

[0084] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET for receiving downlink control information and / or scheduling information corresponding to a particular cell based on the activation or deactivation of the BWP. The WTRU may start or stop monitoring PDCCH resources associated with scheduling of a particular cell upon activation or deactivation of the BWP in that cell (e.g., after receiving a (de)activation BWP switching command or after expiration of a BWP inactivity timer). The WTRU may stop monitoring PDCCH resources associated with scheduling of a PCell if the SCell BWP on which the PDCCH resources reside is deactivated. The WTRU may start monitoring the PDCCH of a different SCell BWP (e.g., either a newly active BWP on the same SCell or a different BWP on a different active serving SCell) or the PCell itself for scheduling the PCell. In one embodiment, the WTRU may monitor the PDCCH on the SCell for PCell scheduling if the active UL and / or DL BWPs on the PCell are from a configured subset of BWPs, a default BWP, an initial BWP, or a non-default BWP.

[0085] In one embodiment, the WTRU may switch, activate, or deactivate PDCCH monitoring on the serving cell, BWP, search space, and / or CORESET for receiving downlink control information and / or scheduling information corresponding to a particular cell based on the detection of beam failure. The WTRU may start or stop monitoring PDCCH resources associated with scheduling of a particular cell when beam failure is detected in the cell to which the PDCCH resources belong or on the PCell. The WTRU may start monitoring the PDCCH on a different SCell for scheduling the PCell when beam failure is detected on the SCell that schedules the PCell.

[0086] In one embodiment, a WTRU may switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET for receiving downlink control information and / or scheduling information corresponding to a particular cell based on a declaration of a radio link failure (RLF). The WTRU may start or stop monitoring PDCCH resources associated with scheduling of a particular cell upon detection of an RLF in the cell to which the PDCCH resources belong or on the PCell. Upon declaring an RLF on an SCell that schedules a PCell, the WTRU may start monitoring the PDCCH on a different SCell for scheduling the PCell.

[0087] In one embodiment, a WTRU may switch, activate, or deactivate PDCCH monitoring on a serving cell, BWP, search space, and / or CORESET for receiving downlink control information and / or scheduling information corresponding to a particular cell based on detection of a consistent UL Listen-Before-Talk (LBT) failure. The WTRU may start or stop monitoring PDCCH resources associated with scheduling of a particular cell upon detection of a consistent UL LBT failure in the cell to which the PDCCH resources belong or on the PCell. Upon detection of a consistent UL LBT failure on an SCell scheduling the PCell, the WTRU may start monitoring the PDCCH on a different SCell for scheduling the PCell.

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

[0089] In one embodiment, the WTRU may select one or more CORESETs to monitor. In one example, the WTRU may select a CORESET in a PCell to monitor whether the number of received DL PDSCHs in the PCell is below a configured threshold for a configured period of time.

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

[0091] In one embodiment, the WTRU may adjust the parameters of CORESET. The WTRU may adjust the parameters of CORESET 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 adjusted CORESET parameters may be one or more of the following: DM-RS scrambling sequence initialization, precoder granularity, number of consecutive symbols (i.e., CORESET duration), or CCE to REG mapping.

[0092] In one embodiment, the WTRU may adjust parameters of the search space set. The WTRU may adjust the parameters of the search space set based on one or more of the triggers described herein. For example, the WTRU may 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 the monitoring pattern, number of PDCCH candidates per CCE aggregation level, or number of aggregation levels.

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

[0094] In one embodiment, a WTRU may be configured with two search space set monitoring patterns. In one example, a first monitoring pattern may be for monitoring physical resources of the search space set on both the SCell and the PCell for the first symbol in a slot, and for monitoring physical resources of the search space set on only the SCell in the second and third symbols of the slot. A second monitoring pattern may be for monitoring physical resources of the search space set on both the SCell and the PCell for the first symbol in a slot, and for monitoring physical resources of the search space set on only the PCell in the second and third symbols of the slot. FIG. 2 shows a method of switching between monitoring patterns (200). The WTRU may monitor a control channel (e.g., a PDCCH) with the first search space set monitoring pattern (210), e.g., as a default. The WTRU may be triggered to switch monitoring patterns (220). For example, the WTRU may receive DCI on the PCell scheduling data on the PCell. The WTRU may switch to the second monitoring pattern based on a triggering (e.g., a received DCI) (230). The WTRU may use the second monitoring pattern for a configured 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. Upon expiration of the timer or upon determining that the configured time period has elapsed, the WTRU may switch back to the first monitoring pattern (240).

[0095] In one embodiment, a WTRU may be configured with three monitoring patterns, and one monitoring pattern may be applied during a switching or transition time. FIG. 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 a default monitoring pattern. The WTRU may be triggered to switch monitoring patterns (320). After being triggered to change the monitoring pattern, 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 with monitoring behavior during flexible symbols when triggered to switch monitoring patterns. For example, the WTRU may be configured to monitor control resources on only the PCell, only the SCell, or both the SCell and the PCell during the flexible symbols.

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

[0097] In one embodiment, a WTRU may receive two DCIs scheduling the same data on a PCell in different control regions (e.g., one DCI in the PCell and another DCI in the SCell). For example, during a transition time from one monitoring pattern to another, the gNB may transmit a DCI on the PCell and a DCI on the SCell to schedule the WTRU on the PCell. This may increase the reliability of control signaling during the switching time. The WTRU may prioritize among the received DCIs. The WTRU may give priority to the DCI received first. In one example, when transitioning from one monitoring pattern to another, if the WTRU detects a first DCI at a particular monitoring occasion, the WTRU may stop monitoring other PDCCH candidates during the transition time. The WTRU may give priority to the DCI received last. For example, the WTRU may receive the first DCI at the first monitoring occasion and continue to monitor other monitoring occasions during the transition period. If the WTRU detects a second DCI, the WTRU may prioritize the second DCI. Prioritization may help the WTRU determine which uplink control channel to use when performing uplink control channel selection.

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

[0099] In one embodiment, the WTRU may select an uplink control channel. The WTRU may be configured with an uplink control channel (i.e., PUCCH resource) on an SCell. In one example, the WTRU may use the uplink control channel of an SCell if a DCI scheduling data or triggering a CSI report for the PCell is received in the SCell control region. For example, the WTRU may receive a scheduling DCI on an SCell that assigns a PDSCH transmission on the PCell. After decoding the PDSCH 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 aperiodic CSI reports for the PCell on the PUCCH on the SCell if a triggering 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 PUCCH transmission.

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

[0101] The WTRU can switch control channel monitoring based on radio link monitoring. In one embodiment, the WTRU can 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 search space set on the PCell. In one embodiment, the WTRU can monitor the control channels on the SCell and not monitor any control channels on the PCell that include a common search space. The WTRU can determine the channel quality on the SCell and, if certain conditions are met, switch to monitoring the control channels on the PCell.

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

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

[0104] The WTRU may start monitoring a configured search space set on a PCell when there is no downlink HARQ feedback indication (DFI) for an uplink transmission. For example, the WTRU may monitor a HARQ DFI in a search space set in an SCell. If the WTRU fails to detect a HARQ DFI, the WTRU may start monitoring a configured search space set on a PCell.

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

[0106] The WTRU may start monitoring a configured search space set on the PCell in the presence or absence of a common signal on the SCell. For example, the WTRU may be configured with a common search space set on the SCell to monitor, for example, a slot format indication, a preemption indication, a cancellation indication, or a new indication for this purpose (e.g., using a new DCI format). If the WTRU does not detect any common control messages for a configured period of time, the WTRU may switch to monitoring the configured search space set on the PCell.

[0107] The WTRU may send an indication to the gNB to indicate a preference for monitoring the PDCCH on a different serving cell for scheduling the PCell. The WTRU may wait for permission from the gNB to change the control channel. The WTRU may send the indication and immediately switch to monitoring the desired control channel. The WTRU may send the indication, wait for a time period or for an event, and then switch to monitoring the desired control channel. For example, the WTRU may switch upon expiration of a time period, or upon receipt of an acknowledgment, or upon receipt of a DCI indication from the gNB. This time period or event may depend on the priority of the expected type of search space / service to be scheduled.

[0108] The WTRU may send an indication to the gNB (520) to indicate a request or preference for PDCCH monitoring on a different serving cell for scheduling the 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 (possibly the PCell itself). Such an indication may be provided by the WTRU by several methods described herein.

[0109] The WTRU may provide the indication by transmitting a scheduling request (SR). The WTRU may trigger a new SR and transmit the SR to the gNB to provide the indication. Such a triggered SR may be transmitted by the WTRU on a subset of PUCCH resources and / or a specific SR configuration. The RRC may configure the WTRU with an SR configuration that can be used and selected by the WTRU when transmitting an SR for this purpose.

[0110] The WTRU may provide the indication by transmitting an indication or uplink control information (UCI) on an uplink channel. The WTRU may include UCI in either the PUCCH or the PUSCH to provide the indication. 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 may be proportional to the number of SCells applicable for scheduling the PCell (e.g., log2(number of possible cells to schedule the PCell)).

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

[0112] The WTRU may provide the indication by transmitting a PRACH. The WTRU may initiate a new random access (RA) procedure and send a preamble to the gNB to provide the indication. Such a preamble may be transmitted by the WTRU on a subset of PRACH resources and may be a prioritized RACH procedure. The RRC may configure the WTRU with PRACH resources (e.g., a subset of preambles and / or RACH opportunities) that may be used and selected by the WTRU when transmitting msg1 or msgA for this purpose.

[0113] The WTRU may provide the indication by transmitting an SRS, which may occur on a configured subset of resources.

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

[0115] The WTRU may be configured to receive one or more DCIs that carry explicit confirmation of the switching request. The DCIs may carry a bit field with one value indicating a positive 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] The WTRU may receive one or more DCIs scheduling DL or UL data as confirmation of the switch request. For example, the WTRU may send a switch request and start monitoring both the PCell and the SCell. If the WTRU receives DL or UL scheduling on the PCell using a control channel on the PCell, the WTRU may interpret the scheduling as confirmation of the switch request and stop monitoring the control channel on the SCell. In one example, the WTRU may receive a DL scheduling DCI or an UL scheduling DCI using a control channel on the SCell. The WTRU may interpret the scheduling as an instruction to stop control channel switching, and the WTRU may continue to monitor the control channel on the SCell.

[0117] The WTRU may be configured to receive a trigger for aperiodic CSI reporting as confirmation of the switch request after a configured period of time requesting a control channel switch. For example, the WTRU may receive the aperiodic CSI reporting request after sending a control channel switch request. The WTRU may stop monitoring the control channel on the PCell and continue to monitor the SCell for the control channel. The WTRU may continue to monitor the control channels on two cells (i.e., the SCell and the PCell) until the WTRU receives an instruction from the gNB to change the configuration. This may allow the network to receive the channel quality of the SCell before reconfiguring the downlink control channel.

[0118] The WTRU may be configured to receive an SCell activation or deactivation command as confirmation of the switch request. In one example, the WTRU may receive a DCI or MAC CE to deactivate the SCell after a configured period of time for sending a control channel switch request. The SCell deactivation command may be interpreted as confirmation to monitor only the control channel on the PCell. In one example, the WTRU may receive a DCI or MAC CE to activate the SCell even if the SCell may already be activated. In this case, the activation command may be interpreted as a negative confirmation of the control channel switch request.

[0119] The active BWP of the scheduling cell and the scheduled cell may have the same subcarrier spacing. The maximum number of PDDCH candidates that a WTRU can process during a timeslot, a set of symbols, or a 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 timeslot, a set of symbols, or a 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 a specification.

[0120] In one embodiment, the WTRU may support a maximum number of PDCCH candidates or non-overlapping CCEs per scheduled cell, and the maximum number of PDCCH candidates or non-overlapping CCEs may be divided or distributed across the scheduling cells of the scheduled cell. For example, in the case where a PCell is scheduled by both a PCell and an SCell, the maximum number of PDCCH candidates or non-overlapping CCEs may be divided or distributed across the PCell and the SCell.

[0121] FIG. 6 shows an example method for monitoring PDCCH candidates for a PCell and an SCell to schedule a PCell. The WTRU may determine 610 a duration for a PDCCH candidate budget for a set of symbols based on a subcarrier spacing associated with the PCell and a subcarrier spacing associated with the SCell. The WTRU may determine 620 a maximum number of PDCCH candidates to allocate to PCell search space monitoring opportunities and SCell search space monitoring opportunities. The maximum number of PDCCH candidates is based on a per-cell ratio. The WTRU may allocate PDCCH candidates for PCell search space monitoring opportunities 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 may be distributed equally across scheduling cells (i.e., PCell and SCells) of the scheduled cell (i.e., PCell). A WTRU may support a maximum number (M) of PDCCH candidates and a maximum number (C) of non-overlapping CCEs for scheduling on the PCell. If a WTRU is configured with an SCell and a PCell for scheduling on the PCell, the WTRU may assume a maximum number of M / 2 PDCCH candidates and a maximum number of C / 2 non-overlapping CCEs on the PCell, and a maximum number of M / 2 PDCCH candidates and a maximum number of C / 2 non-overlapping CCEs on the SCell.

[0123] In one embodiment, the WTRU may be configured, for example using RRC signaling, with a fraction or percentage of the maximum number of PDCCH candidates or a percentage of the maximum number of non-overlapping CCEs to be considered per scheduling cell of the scheduled cell. The WTRU may be configured to determine the percentage of the maximum number of PDCCH candidates or non-overlapping CCEs to be considered per scheduling cell of the scheduled cell based on a search space set monitoring configuration. At the beginning of a set of slots or symbols, the WTRU may filter out scheduling cells that do not have a search space monitoring opportunity in the set of slots or symbols for the scheduled cell.

[0124] For example, the WTRU may be configured with a first search space monitoring pattern in the PCell and a second search space monitoring pattern in the SCell for PCell scheduling. At the beginning of a set of slots or symbols, the WTRU may determine that the PCell does not have any monitoring opportunities within the set of slots or symbols for PCell scheduling and may assume that the maximum number of PDCCH candidates or non-overlapping CCEs are all within the SCell. The WTRU may use the RRC configuration of the set of search spaces to monitor for scheduling on the PCell to determine the maximum number of PDCCH candidates for scheduling.

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

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

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

[0128] Figure 7 shows the maximum number (M) of PDCCH blind decoding (BD) candidates and the maximum number (C) of non-overlapping CCEs for PCell scheduling. In Figure 7, Mx,i denotes the maximum number of PDCCH candidates, where x = 1 denotes the PCell, x = 2 denotes the SCell, and i denotes the duration. As shown in Figure 7, the PCell is configured with 15 kHz subcarrier spacing, with M1,1 > M2,1 and C1,1 > C2,1 per first duration. The maximum number of PDCCH candidates for scheduling on the PCell per duration is M = M1,1 + M2,1 = M2,2. The maximum number of non-overlapping CCE candidates for scheduling on the 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 may 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 for some time slots or subframes. For example, in FIG. 7, SCell and PCell are scheduling cells for the PCell, where the SCell is configured with 30 KHz subcarrier spacing and the PCell is configured with 15 KHz subcarrier spacing. During the first time slot of the SCell, the maximum number of PDCCH candidates is M2,1 and the maximum number of non-overlapping CCEs is C2,1. During the second timeslot of the 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 with the PCell and SCell to schedule PDSCH / PUSCH on the PCell. The WTRU may 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 may determine the maximum number M1,i of PDCCH candidates on the PCell for PCell scheduling and the maximum number M2,i of PDCCH candidates on the SCell for PCell scheduling.

[0131] The WTRU may distribute or allocate the maximum number of PDCCH candidates or non-overlapping CCEs for each scheduled cell across the scheduling cells of the scheduled cell. Distribution or allocation may refer to the processing capacity for the scheduling cell 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 determine to allocate to the scheduling cell a fraction or percentage (i.e., less than a maximum value) of the number of PDCCH candidates or non-overlapping CCEs per scheduled cell. At the beginning of a duration or a set of timeslots or symbols, the WTRU may determine a fraction of the maximum number of PDCCH candidates or non-overlapping CCEs for the scheduling cell based on the number of configured PDCCH candidates or non-overlapping CCEs on the search space set on the scheduling cell relative to the total number of configured PDCCHs / non-overlapping CCEs for the scheduled cell. For example, the WTRU may be configured with a PCell and an SCell to schedule a PDSCH / PUSCH on the PCell. At the beginning of the duration, the WTRU may be configured with N1 PDCCH candidates on the PCell for PCell scheduling and N2 PDCCH candidates on the SCell for PCell scheduling. The WTRU may determine that a portion or percentage of the maximum number of PDCCH candidates for PCell scheduling on a PCell is equal to N1 / (N1+N2), and that a portion or percentage of the maximum number of PDCCH candidates for PCell scheduling on an SCell is equal to N2 / (N1+N2). The WTRU may assume the maximum number of PDCCH candidates to be MxN2 / (N1+N2) on the PCell and MxN1 / (N1+N2) on the SCell for each duration / timeslot / symbol set, where M is the maximum number of PDCCH candidates for PCell scheduling using all scheduling cells. The WTRU may not monitor the remaining N1-MxN1 / (N1+N2) candidates on the PCell and the remaining N2-MxN2 / (N1+N2) candidates on the SCell. Similarly, for the number of non-overlapping CCEs, the WTRU may assume a maximum number of non-overlapping CCEs of CxK1 / (K1+K2) on the PCell and CxK1 / (K1+K2) on the 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 may be configured to determine a fraction or percentage of the maximum number of PDCCH candidates or non-overlapping CCEs for the scheduling cell based on the frequency bandwidth configured for a CORESET on the scheduling cell for scheduling on the scheduled cell over the total frequency bandwidth configured for all CORESETs on different scheduling cells for scheduling on the scheduled cell. In one embodiment, the WTRU may determine a fraction or percentage of the maximum number of PDCCH candidates or non-overlapping CCEs for the scheduling cell based on the frequency bandwidth of the active bandwidth portion of the scheduling cell over the total frequency bandwidth of the active bandwidth portion configured for scheduling on the scheduled cell.

[0134] In one embodiment, the WTRU may assume that the maximum number of PDCCH candidates or non-overlapping CCEs for a scheduling cell per set of durations or timeslots or symbols is equal to the number of PDCCH candidates / non-overlapping CCEs configured on the search space set on the scheduling cell per set of durations / timeslots / symbols. For example, a WTRU may be configured with a PCell and an SCell to schedule a PDSCH / PUSCH on the PCell. The WTRU may be configured with a search space set on the PCell with N PDCCH candidates and K non-overlapping CCEs for scheduling on the PCell. The WTRU may be configured with a search space set on the SCell with N PDCCH candidates and K non-overlapping CCEs for scheduling on the PCell. The WTRU may assume that the maximum number of PDCCH candidates is equal to N on the SCell and M-N on the PCell, per set of durations / timeslots / symbols, where M is the maximum number of PDCCH candidates for PCell scheduling using all scheduling cells. The UE may not drop or monitor N1-(M-N2) PDCCH candidates on the PCell. For non-overlapping CCEs, the WTRU may assume that the maximum number of non-overlapping CCEs is equal to K2 on the SCell and C-K2 on the PCell per set of duration / timeslot / 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 be configured with a set of search spaces with a total number of PDCCH candidates / non-overlapping CCEs that exceeds the maximum number of PDCCH candidates / non-overlapping CCEs per scheduled cell. The WTRU may prioritize the configured PDCCH candidates / non-overlapping CCEs and / or search spaces and may monitor only a subset of the configured PDCCH candidates / non-overlapping CCEs and / or search spaces. In one embodiment, the WTRU may prioritize between search spaces on different scheduling cells for a scheduled cell. At the start of a timeslot / set of symbols / duration, the WTRU may prioritize the search spaces by at least search space priority or search space index.

[0136] 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 may 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 a priority parameter. For example, for scheduling on a PCell, a set of search spaces may be configured on the PCell and SCell, and each search space may be associated with a priority. At the beginning of a timeslot / symbol set / duration, the WTRU may select search spaces in order of priority (e.g., ascending order of priority) until the maximum number of PDCCH candidates / number of non-overlapping CCEs per timeslot / symbol set / duration is reached. The WTRU may monitor the selected search spaces. As shown in FIG. 9, the order or monitoring (p1, p2, p3, and p4) is PCell search space 0, PCell search space 1, SCell search space 0, and SCell search space 1.

[0138] In one embodiment, the WTRU may prioritize search spaces based on search space index, as shown in FIG. 10. For scheduling on a PCell, a set of search spaces may be configured on the PCell and the SCell. At the start of a timeslot / symbol set / duration, the WTRU may select search spaces on the PCell in ascending order of search space index; after selecting all search spaces in the PCell and if the maximum number of PDCCH candidates / non-overlapping CCEs has not been reached, the WTRU may select search spaces on the SCell in ascending order of search space index until the maximum number of PDCCH candidates / non-overlapping CCEs per timeslot / symbol set / duration is reached. The WTRU may monitor the selected search spaces. As shown in FIG. 10, the order or monitoring (p1, p2, p3, and p4) is PCell search space 0, SCell search space 0, PCell search space 1, and SCell search space 1.

[0139] In one embodiment, at the beginning of a timeslot / symbol set / duration, the WTRU may select the search space with the lower search space index from the PCell and the search space with the 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 be configured with two search spaces on the PCell (i.e., search space 0 and search space 1) and two search spaces on the SCell (i.e., search space 0 and search space 1). The WTRU may select search space 0 on the PCell, and if the maximum number of PDCCH candidates / non-overlapping CCEs has not been reached, the WTRU may select search space 0 on the SCell. If the maximum number of PDCCH candidates / non-overlapping CCEs has not been reached, the WTRU may select search space 1 on the PCell. If the maximum number of PDCCH candidates / non-overlapping CCEs has not been reached, the UE may select search space 1 on the SCell (p1 / p2 / p3 / p4 are the priorities for monitoring the search spaces, as shown in FIG. 5B).

[0141] If a search space is selected to be monitored, there will be some remaining PDCCH candidates / non-overlapping CCEs that the WTRU can process, so the WTRU may drop or not monitor some PDCCH candidates / CCEs in the search space, but the overall PDCCH candidates / CCEs configured for that search space would 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 of 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, if the configured CCEs for the search space would result in exceeding the maximum number of PDCCH candidates / number of non-overlapping CCEs, the WTRU may be configured to select CCEs with lower indices to monitor.

[0143] Although features and elements are described above in particular combinations, those skilled in the art will understand that each feature or element may be used alone or in any combination with the other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium 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 in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. 1. A method implemented by a wireless transmit / receive unit (WTRU) configured to monitor physical downlink control channel (PDCCH) candidates of a primary cell (PCell) and a secondary cell (SCell), comprising: determining a duration for a PDCCH candidate budget for a set of symbols based on a subcarrier spacing associated with the PCell and a subcarrier spacing associated with the SCell; determining a maximum number of PDCCH candidates to allocate to search space monitoring opportunities for the PCell and search space monitoring opportunities for the SCell, where the maximum number of PDCCH candidates is based on a per-cell ratio; allocating PDCCH candidates for the search space monitoring opportunities of the PCell and the search space monitoring opportunities of the SCell based on the determined maximum number of PDCCH candidates; and decoding the allocated PDCCH candidates.

2. determining whether there are overlapping PCell and SCell search space monitoring opportunities within the set of symbols; The maximum number of PDCCH candidates to be allocated is determined on the condition that there are overlapping search space monitoring opportunities. The method of claim 1.

3. 2. The method of claim 1, wherein the decoding comprises receiving scheduling information associated with a physical downlink shared channel (PDSCH) or a physical uplink shared channel (PUSCH) of the PCell.

4. The method of claim 3 , wherein the scheduling information is received in downlink control information (DCI).

5. The method of claim 1 , wherein the subcarrier spacing associated with the PCell and the subcarrier spacing associated with the SCell are different.

6. The method of claim 1 , wherein the determined duration is a minimum time slot associated with the subcarrier spacing of the PCell and the subcarrier spacing of the SCell.

7. 2. The method of claim 1, wherein the per-cell ratio is determined based on a number of configured PDCCH candidates (N1) on the PCell and a number of configured downlink control channel candidates (N2) on the SCell.

8. 8. The method of claim 7, wherein the maximum number of PDCCH candidates for the PCell is based on the number (N1) of configured PDCCH candidates for the PCell as a percentage of the total number (N1+N2) of configured PDCCH candidates for the PCell and the SCell.

9. 8. The method of claim 7, wherein the maximum number of PDCCH candidates for the SCell is based on the number (N2) of configured PDCCH candidates for the SCell as a percentage of the total number (N1 + N2) of configured PDCCH candidates for the PCell and the SCell.

10. The method of claim 1 , further comprising prioritizing the search spaces to monitor based on search space priority or search space index.

11. 1. A wireless transmit / receive unit (WTRU) configured to monitor physical downlink control channel (PDCCH) candidates of a primary cell (PCell) and a secondary cell (SCell), the WTRU comprising: a processor, the processor comprising: determining a duration for a PDCCH candidate budget for a set of symbols based on a subcarrier spacing associated with the PCell and a subcarrier spacing associated with the SCell; determining a maximum number of PDCCH candidates to allocate to search space monitoring opportunities of the PCell and search space monitoring opportunities of the SCell, where the maximum number of PDCCH candidates is based on a per-cell ratio; Allocating PDCCH candidates for the search space monitoring opportunities of the PCell and the search space monitoring opportunities of the SCell based on the determined maximum number of PDCCH candidates; and The WTRU is configured to decode the allocated PDCCH candidates.

12. 12. The WTRU of claim 11, wherein the processor is further configured to determine whether there are overlapping PCell and SCell search space monitoring opportunities in the set of symbols, and wherein the maximum number of PDCCH candidates to allocate is determined on the condition that there are overlapping search space monitoring opportunities.

13. The WTRU of claim 11 , wherein the decoded PDCCH includes scheduling information associated with a physical downlink shared channel (PDSCH) or a physical uplink shared channel (PUSCH) of the PCell.

14. The WTRU of claim 13 , wherein the scheduling information is in downlink control information (DCI).

15. The WTRU of claim 11 , wherein the subcarrier spacing associated with the PCell and the subcarrier spacing associated with the SCell are different.

16. The WTRU of claim 11 , wherein the determined duration is a minimum time slot associated with the subcarrier spacing of the PCell and the subcarrier spacing of the SCell.

17. The WTRU of claim 11 , wherein the per-cell ratio is determined based on a number of configured PDCCH candidates on the PCell (N1) and a number of configured PDCCH candidates on the SCell (N2).

18. 18. The WTRU of claim 17, wherein the maximum number of PDCCH candidates for the PCell is based on the number (N1) of configured PDCCH candidates for the PCell as a percentage of the total number (N1 + N2) of configured PDCCH candidates for the PCell and the SCell.

19. 18. The WTRU of claim 17, wherein the maximum number of PDCCH candidates for the SCell is based on the number (N2) of configured PDCCH candidates for the SCell as a percentage of the total number (N1 + N2) of configured PDCCH candidates for the PCell and the SCell.

20. The WTRU of claim 11 , wherein the processor is further configured to prioritize the search spaces to monitor based on a search space priority or a search space index.

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