Methods for Physical Downlink Control Channel (PDCCH) Candidate Determination

Abstract

The Wireless Transmit / Receive Unit (WTRU) determines PDCCH candidates. For a time slot, the WTRU determines the number of valid PDCCH candidates associated with at least one search space based on the following: the number of designated search spaces associated with the WTRU in the time slot, the type of the search space, the priority associated with the search space, the number of required CCE channel estimates associated with the search space, the maximum number of PDCCH candidates in the time slot, and the number of control resource sets (CORESETs) associated with the time slot. The WTRU can then attempt to decode the CCEs in the at least one search space to recover the PDCCH associated with the WTRU. When the number of PDCCHs exceeds the maximum value, the WTRU can discard PDCCH candidates from the search space.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201880084873.1, filed on November 14, 2018, entitled “Method for Physical Downlink Control Channel (PDCCH) Candidate Determination,” which is incorporated herein by reference as if it were fully set forth herein.

[0002] Cross-references to related applications

[0003] This application claims the benefits of U.S. Provisional Application No. 62 / 585,992, filed November 14, 2017, and U.S. Provisional Application No. 62 / 615,787, filed January 10, 2018, which are incorporated herein by reference as if they were fully set forth herein. Background Technology

[0004] A Radio Access Network (RAN) is part of a mobile telecommunications system that provides Radio Transmitter / Receiver Units (WTRUs) with access to the Core Network (CN). In fifth-generation (5G) or next-generation (NG) radio systems, the RAN may be referred to as New Radio (NR) or Next-Generation RAN. NR is designed to support high flexibility. This flexibility ensures that WTRUs with varying capabilities can simultaneously serve different types of services. The different capabilities of NR are variable and can be categorized as Extreme Mobile Broadband (eMBB), Ultra-Reliable and Low-Latency Communication (URLLC), and Massive Machine-Type Communication (mMTC). Furthermore, NR needs to support transmissions in higher frequency bands, such as centimeter (cm) wave frequencies and millimeter (mm) wave frequencies. To support all these capabilities and transmission methods, the WTRU may need to monitor multiple Physical Downlink Control Channel (PDCCH) candidates and determine when they are scheduled to receive data transmissions. Therefore, the WTRU will need to examine all possible PDCCH candidates, which can necessarily increase blind detection complexity. Therefore, it is desirable to limit this blind detection complexity by determining which PDCCH candidates need to be monitored at any given time. Summary of the Invention

[0005] The Wireless Transmit / Receive Unit (WTRU) determines PDCCH candidates. For a time slot, the WTRU determines the number of valid PDCCH candidates associated with at least one search space based on the following: the number of designated search spaces associated with the WTRU in the time slot, the type of the search space, the priority associated with the search space, the number of required CCE channel estimates associated with the search space, the maximum number of PDCCH candidates in the time slot, and the number of control resource sets (CORESETs) associated with the time slot. The WTRU can then attempt to decode the CCEs in the at least one search space to recover the PDCCH associated with the WTRU. When the number of PDCCHs exceeds the maximum value, the WTRU can discard PDCCH candidates from the search space. Attached Figure Description

[0006] The invention can be understood in more detail from the following description given by way of example in conjunction with the accompanying drawings, wherein like reference numerals denote like elements, and wherein:

[0007] Figure 1A This is a system schematic diagram illustrating an exemplary communication system that can implement one or more of the disclosed embodiments;

[0008] Figure 1B It is shown that, according to the embodiment, it is possible to Figure 1A A schematic diagram of an exemplary wireless transmit / receive unit (WTRU) used within a communication system.

[0009] Figure 1C It is shown that, according to the embodiment, it is possible to Figure 1A The diagram shows an exemplary radio access network (RAN) and an exemplary core network (CN) used within the communication system.

[0010] Figure 1D It is shown that, according to the embodiment, it is possible to Figure 1A The diagram shows another exemplary RAN and another exemplary CN used within the communication system.

[0011] Figure 2 This is a schematic diagram illustrating an example physical downlink control channel (PDCCH) candidate allocation within a variable number of control resource sets (CORESET) in each time slot;

[0012] Figure 3 This is a schematic diagram illustrating example PDCCH candidate allocation for different discontinuous reception (DRX) states;

[0013] Figure 4This is a flowchart illustrating the algorithm for discarding PDCCH candidates from the search space; and

[0014] Figure 5 This is a flowchart illustrating a method for determining a PDCCH candidate according to an embodiment described herein. Detailed Implementation

[0015] Figure 1A This is a schematic diagram illustrating an exemplary communication system 100 that can implement one or more of the disclosed embodiments. The communication system 100 can be a multiple access system providing content such as voice, data, video, messaging, and broadcasting to multiple wireless users. The communication system 100 enables multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, the communication system 100 can 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 DFT-Extended OFDM (ZT UW DTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtering OFDM, and Filter Bank Multicarrier (FBMC), etc.

[0016] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110, and other networks 112. However, it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network components. Each of WTRUs 102a, 102b, 102c, and 102d can be any type of device configured to operate and / or communicate in a wireless environment. For example, any of WTRUs 102a, 102b, 102c, and 102d can be referred to as a “station” and / or “STA”, and can be configured to transmit and / or receive wireless signals. They can include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronics, and devices operating on commercial and / or industrial wireless networks, etc. Any of WTRUs 102a, 102b, 102c, and 102d can be interchangeably referred to as a UE.

[0017] The communication system 100 may further include base station 114a and / or base station 114b. Each of base stations 114a and 114b may be any type of device configured to enable access to one or more communication networks (e.g., CN 106 / 115, Internet 110, and / or other networks 112) by wirelessly interfacing with at least one of WTRUs 102a, 102b, 102c, and 102d. For example, base stations 114a and 114b may be base transceiver stations (BTS), node B, e-node B, home node B, home e-node B, gNB, new radio (NR) node B, site controller, access point (AP), and wireless routers, etc. Although each of base stations 114a and 114b is described as a single component, it should be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network components.

[0018] Base station 114a may be part of RAN 104 / 113, and the RAN may also include other base stations and / or network components (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies called cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide radio service coverage for a specific geographic area that is relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., each transceiver corresponds to one sector of the cell. In embodiments, base station 114a may use multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. For example, by using beamforming, signals can be transmitted and / or received in a desired spatial direction.

[0019] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116, wherein the air interface can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 can be established using any suitable radio access technology (RAT).

[0020] More specifically, as described above, the communication system 100 can be a multiple access system and can use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA, etc. For example, base station 114a in RAN 104 / 113 and WTRUs 102a, 102b, and 102c can implement a certain radio technology, such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), wherein the technology can use Wideband CDMA (WCDMA) to establish air interfaces 115 / 116 / 117. WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

[0021] In an embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement a certain radio technology, such as Evolved UMTS Terrestrial Radio Access (E-UTRA), wherein the technology may use Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro) to establish air interface 116.

[0022] In an embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement a radio technology that can establish an air interface 116 using a new radio (NR), such as NR radio access.

[0023] In this embodiment, base station 114a and WTRUs 102a, 102b, and 102c can implement various radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can jointly implement LTE radio access and NR radio access (e.g., using the dual connectivity (DC) principle). Therefore, the air interface used by WTRUs 102a, 102b, and 102c can be characterized by various types of radio access technologies and / or transmissions sent to / from various types of base stations (e.g., eNBs and gNBs).

[0024] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c may implement the following radio technologies, such as IEEE 802.11 (i.e., WiFi), IEEE 802.16 (i.e., WiMAX), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate for GSM Evolution (EDGE), and GSM EDGE (GERAN), etc.

[0025] Figure 1ABase station 114b can be, for example, a wireless router, home node B, home e node B, or access point, and can use any suitable RAT to facilitate wireless connectivity in a local area, such as a business premises, residence, vehicle, campus, industrial facility, air corridor (e.g., for use by drones), and road, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can establish a wireless local area network (WLAN) by implementing radio technology such as IEEE 802.11. In another embodiment, base station 114b and WTRUs 102c, 102d can establish a wireless personal area network (WPAN) by implementing radio technology such as IEEE 802.15. In yet another embodiment, base station 114b and WTRUs 102c, 102d can establish a picocell or femtocell by using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). Figure 1A As shown, base station 114b can be directly connected to the Internet 110. Therefore, base station 114b does not need to access the Internet 110 via CN 106 / 115.

[0026] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRU 102a, 102b, 102c, and 102d. This data can have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements, etc. CN 106 / 115 can provide call control, billing services, location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or can perform advanced security functions such as user authentication. Although in Figure 1A While not shown, it should be understood that RAN104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that use the same RAT or a different RAT as RAN 104 / 113. For example, in addition to connecting to RAN 104 / 113 which uses NR radio technology, CN 106 / 115 can also communicate with other RANs (not shown) that use GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technologies.

[0027] CN 106 / 115 can also act as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Simple Old-Style Telephone Service (POTS). The Internet 110 may include a global interconnected computer network equipment system using common communication protocols (e.g., TCP, UDP, and / or IP from the Transmission Control Protocol / Internet Protocol (TCP / IP) suite). Network 112 may include wired or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, wherein the one or more RANs may use the same RAT or a different RAT as RAN 104 / 113.

[0028] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multi-mode capability (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers communicating with different wireless networks on different wireless links). For example, Figure 1A The WTRU 102c shown can be configured to communicate with base station 114a using cellular-based radio technology, and with base station 114b using IEEE 802 radio technology.

[0029] Figure 1B This is a system schematic diagram illustrating an exemplary WTRU 102. (See attached diagram.) Figure 1B As shown, WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive unit 122, a speaker / microphone 124, a numeric keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or peripheral devices 138. It should be understood that, while remaining consistent with the embodiments, WTRU 102 may also include any sub-combination of the foregoing components.

[0030] Processor 118 can 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) circuit, any other type of integrated circuit (IC), and a state machine, etc. Processor 118 can perform signal encoding, data processing, power control, input / output processing, and / or any other function that enables WTRU 102 to operate in a wireless environment. Processor 118 can be coupled to transceiver 120, and transceiver 120 can be coupled to transmitting / receiving unit 122. Although Figure 1B While the processor 118 and transceiver 120 are described as separate components, it should be understood that the processor 118 and transceiver 120 may also be integrated together in a single electronic component or chip.

[0031] Transmit / receive component 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) via air interface 116. For example, in one embodiment, transmit / receive component 122 may be an antenna configured to transmit and / or receive RF signals. As an example, in another embodiment, transmit / receive component 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, transmit / receive component 122 may be configured to transmit and / or receive RF and optical signals. It should be understood that transmit / receive component 122 may be configured to transmit and / or receive any combination of wireless signals.

[0032] Although Figure 1B While the transmit / receive component 122 is described as a single component, the WTRU 102 may include any number of transmit / receive components 122. More specifically, the WTRU 102 may use MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive components 122 (e.g., multiple antennas) that transmit and receive wireless signals via the air interface 116.

[0033] Transceiver 120 can be configured to modulate signals to be transmitted by transmitter / receiver 122 and demodulate signals received by transmitter / receiver 122. As described above, WTRU 102 can have multimode capability. Therefore, transceiver 120 can include multiple transceivers that allow WTRU 102 to communicate using various RATs (e.g., NR and IEEE 802.11).

[0034] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a numeric keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit), and can receive user input data from these components. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 can access and store information from any suitable memory, such as non-removable memory 130 and / or removable memory 132. Non-removable memory 130 can include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 can include a subscriber identity module (SIM) card, memory stick, secure digital card (SD) memory card, etc. In other embodiments, the processor 118 can access and store information from memory that is not actually located in WTRU 102; for example, such memory could be located in a server or home computer (not shown).

[0035] The processor 118 can receive power from the power supply 134 and can be configured to distribute and / or control power for other components in the WTRU 102. The power supply 134 can be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry cell battery packs (such as nickel-cadmium (Ni-Cd), nickel-zinc (Ni-Zn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, and fuel cells, etc.

[0036] 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) related to the current location of the WTRU 102. As a supplement or replacement to the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the air interface 116, and / or determine its location based on signal timing received from two or more nearby base stations. It should be understood that, while remaining consistent with the embodiments, the WTRU 102 may acquire location information using any suitable positioning method.

[0037] The processor 118 can also be coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wired or wireless connectivity. For example, the peripheral device 138 may include an accelerometer, electronic compass, satellite transceiver, digital camera (for photos and / or video), Universal Serial Bus (USB) port, vibration device, television transceiver, hands-free headset, etc. Modules, FM radio units, digital music players, media players, video game console modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, and activity trackers, etc. The peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors, geolocation sensors, altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors, etc.

[0038] WTRU 102 may include a full-duplex wireless device, wherein the reception or transmission of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous for the wireless device. The full-duplex wireless device may include an interference management unit 139 that reduces and / or substantially eliminates self-interference by means of hardware (e.g., choke coils) or by means of a processor (e.g., a separate processor (not shown) or by means of processor 118) for signal processing. In embodiments, WTRU 102 may include a half-duplex wireless device that transmits and receives some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception).

[0039] Figure 1C This diagram illustrates a system schematic of RAN 104 and CN 106 according to an embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0040] RAN 104 may include eNodeBs 160a, 160b, and 160c; however, it should be understood that RAN 104 may include any number of eNodeBs while remaining consistent with the embodiments. Each of eNodeBs 160a, 160b, and 160c may include one or more transceivers communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, eNodeBs 160a, 160b, and 160c may implement MIMO technology. Thus, for example, eNodeB 160a may use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a.

[0041] Each of the eNodeB 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. For example... Figure 1C As shown, nodes B160a, 160b, and 160c can communicate with each other via the X2 interface.

[0042] Figure 1C The CN 106 shown may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. While each of the foregoing components is described as part of the CN 106, it should be understood that any of these components may be owned and / or operated by an entity other than the CN operator.

[0043] The MME 162 can connect to each of the eNodeBs 162a, 162b, and 162c in RAN 104 via the S1 interface and can act as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, performing bearer activation / deactivation processes, and selecting a specific serving gateway during the initial attach process of WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) using other radio technologies (such as GSM and / or WCDMA).

[0044] The SGW 164 can connect to each of the eNodeBs 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 typically routes and forwards user data packets to / from WTRUs 102a, 102b, and 102c. Furthermore, the SGW 164 can perform other functions, such as anchoring the user plane during handover between eNBs, triggering paging processes when DL data is available to WTRUs 102a, 102b, and 102c, and managing and storing the context of WTRUs 102a, 102b, and 102c, etc.

[0045] SGW 164 can be connected to PGW 146, which can provide packet-switched network (e.g., Internet 110) access for WTRUs 102a, 102b, and 102c to facilitate communication between WTRUs 102a, 102b, and 102c and IP-enabled devices.

[0046] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRUs 102a, 102b, and 102c with access to a circuit-switched network (e.g., PSTN 108) to facilitate communication between WTRUs 102a, 102b, and 102c and conventional landline communication equipment. For example, CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server), and the IP gateway may act as an interface between CN 106 and PSTN 108. Furthermore, CN 106 can provide WTRUs 102a, 102b, and 102c with access to the other network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0047] Although Figure 1A-1D The WTRU is described as a wireless terminal; however, it should be understood that in some representative embodiments, such a terminal may use a wired communication interface (e.g., temporary or permanent) with the communication network.

[0048] In a representative embodiment, the other network 112 may be a WLAN.

[0049] A WLAN employing an Infrastructure Basic Services Set (BSS) model may have an Access Point (AP) for the BSS and one or more Stations (STAs) associated with the AP. The AP may access or interface with a Distributed System (DS) or other types of wired / wireless networks that send traffic into and / or out of the BSS. Traffic originating outside the BSS and destined for a STA can be delivered to the STA via the AP. Traffic originating from a STA and destined for a destination outside the BSS can be sent to the AP for delivery to the appropriate destination. Traffic between STAs within the BSS can be sent via the AP, for example, where a source STA can send traffic to the AP and the AP can deliver traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic can be sent between the source and destination STAs (e.g., directly therebetween) using Direct Link Establishment (DLS). In some representative embodiments, the DLS may use 802.11e DLS or 802.11z Channelized DLS (TDLS). For example, a WLAN using the Standalone BSS (IBSS) mode does not have an access point (AP) and is located within the IBSS or the STAs using the IBSS (e.g., all STAs) can communicate directly with each other. Here, the IBSS communication mode is sometimes referred to as an "ad-hoc" communication mode.

[0050] When operating in 802.11ac infrastructure mode or a similar mode, the AP can transmit beacons on a fixed channel (e.g., the primary channel). The primary channel can have a fixed width (e.g., a 20 MHz bandwidth) or a width dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by STAs to establish connections with the AP. In some representative embodiments, carrier-sense multiple access with collision avoidance (CSMA / CA) can be implemented (e.g., in an 802.11 system). For CSMA / CA, STAs, including the AP (e.g., each STA), can sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, then that particular STA can back off. In a given BSS, at any given time, there is only one STA (e.g., only one station) transmitting.

[0051] High-throughput (HT) STAs can communicate using a 40MHz wide channel (e.g., by combining a 20MHz wide main channel with adjacent or non-adjacent 20MHz wide channels to form a 40MHz wide channel).

[0052] Very High Throughput (VHT) STAs can support channels with widths of 20MHz, 40MHz, 80MHz, and / or 160MHz. 40MHz and / or 80MHz channels can be formed by combining consecutive 20MHz channels. A 160MHz channel can be formed by combining eight consecutive 20MHz channels or by combining two non-consecutive 80MHz channels (this combination may be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, data is transmitted and passed through a segmented parser that splits the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing can be performed individually on each stream. The streams can be mapped onto two 80MHz channels, and the data can be transmitted by the STA performing the transmission. On the receiver of the STA performing the reception, the above operations for the 80+80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC).

[0053] 802.11af and 802.11ah support sub-1 GHz operating modes. Compared to 802.11n and 802.11ac, 802.11af and 802.11ah utilize reduced channel bandwidth and carriers. 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 a representative embodiment, 802.11ah can support instrument-type control / machine-type communication (MTC) (e.g., MTC devices in macro coverage areas). MTC devices may have certain capabilities, such as limited capabilities including support (e.g., only support) certain and / or limited bandwidths. MTC devices may include a battery with a battery life exceeding a threshold (e.g., for maintaining a very long battery life).

[0054] For WLAN systems that can support multiple channels and channel bandwidths (e.g., 802.11n, 802.11ac, 802.11af, and 802.11ah), these systems include a channel that can be designated as the primary channel. The bandwidth of the primary channel can be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by a single STA, which is derived from all STAs operating in the BSS supporting the minimum bandwidth operating mode. In the example of 802.11ah, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes, the width of the primary channel can be 1MHz for STAs that support (e.g., only support) the 1MHz mode (e.g., MTC type devices). Carrier sensing and / or Network Allocation Vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy (e.g., because an STA (which only supports the 1MHz operating mode) is transmitting to the AP), then the entire available band can be considered busy even if most of the available band remains idle and available.

[0055] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. Depending on the country code, the total bandwidth available for 802.11ah is 6MHz to 26MHz.

[0056] Figure 1D This diagram illustrates a system schematic of RAN 113 and CN 115 according to an embodiment. As described above, RAN 113 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0057] RAN 113 may include gNBs 180a, 180b, and 180c; however, it should be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiments. Each of gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may use beamforming to transmit and / or receive signals to and / or from gNBs 180a, 180b, and 180c. Thus, for example, gNB 180a may use multiple antennas to transmit radio signals to and receive radio signals from WTRU 102a. In embodiments, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In embodiments, gNBs 180a, 180b, and 180c may implement Cooperative Multipoint (CoMP) technology. For example, WTRU 102a can receive cooperative transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0058] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable digital configurations. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing can be different for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., containing different numbers of OFDM symbols and / or varying absolute durations).

[0059] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNodeBs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can use one or more of gNBs 180a, 180b, and 180c as mobile anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can use signals in unlicensed frequency bands to communicate with gNBs 180a, 180b, and 180c. In a non-standalone configuration, WTRUs 102a, 102b, and 102c communicate / connect with gNBs 180a, 180b, and 180c simultaneously with other RANs (e.g., eNodeBs 160a, 160b, and 160c). For example, WTRUs 102a, 102b, and 102c can communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c, as well as one or more eNodeBs 160a, 160b, and 160c, by implementing DC principles. In a non-standalone configuration, eNodeBs 160a, 160b, and 160c can act as mobile anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRUs 102a, 102b, and 102c.

[0060] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support network slicing, dual connectivity, implement interoperability processing between NR and E-UTRA, route user plane data to User Plane Functions (UPF) 184a and 184b, and route control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, etc. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0061] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and may include data network (DN) 185a, 185b. While each of the foregoing components is described as part of CN 115, it should be understood that any of these components may be owned and / or operated by an entity other than a CN operator.

[0062] AMF 182a and 182b can connect to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can act as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different needs), selecting specific SMFs 183a and 183b, managing registration areas, terminating NAS signaling, and mobility management, etc. AMF 182a and 182b can use network slicing to customize the CN support provided to WTRU 102a, 102b, and 102c based on the service types used by WTRU 102a, 102b, and 102c. As an example, different network slices can 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, and / or services for Machine-Type Communication (MTC) access, etc. AMF 182 can provide control plane functions for switching between RAN 113 and other RANs (not shown) using other radio technologies (e.g., LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi).

[0063] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and can configure traffic routing through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating WTRU or UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications, etc. PDU session types can be IP-based, non-IP-based, and Ethernet-based, etc.

[0064] UPF 184a and 184b can connect to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N3 interface, thus providing WTRU 102a, 102b, and 102c with access to a packet-switched network (e.g., Internet 110) to facilitate communication between WTRU 102a, 102b, and 102c and IP-enabled devices. UPF 184 and 184b can perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multihomed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring, etc.

[0065] CN 115 can facilitate communication with other networks. For example, CN 115 may include or can communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 115 and PSTN 108. Furthermore, CN 115 can provide WTRUs 102a, 102b, and 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, WTRUs 102a, 102b, and 102c can be connected to DNs 185a and 185b via the N3 interface connected to UPFs 184a and 184b and the N6 interface between UPFs 184a and 184b and local data networks (DNs) 185a and 185b.

[0066] In view of Figure 1A-1D And about Figure 1A-1D The corresponding descriptions herein refer to one or more of the following functions, which can be performed by one or more emulation devices (not shown): WTRU 102a-d, Base Station 114a-b, eNodeB 160a-c, MME 162, SGW164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN185a-b, and / or one or more other devices described herein. These emulation devices can be one or more devices configured to simulate one or more of the functions described herein. For example, these emulation devices can be used to test other devices and / or simulate network and / or WTRU functions.

[0067] The simulation device can be designed to perform one or more tests on other devices in a laboratory environment and / or a carrier network environment. For example, the one or more simulation devices can perform one or more functions while being implemented and / or deployed, wholly or partially, as part of a wired and / or wireless communication network, to test other devices within the communication network. The one or more simulation devices can perform one or more functions while being implemented or deployed temporarily as part of a wired and / or wireless communication network. The simulation device can be directly coupled to other devices to perform tests, and / or can use over-the-air wireless communication to perform tests.

[0068] One or more simulation devices can perform one or more functions, including all functionalities, without being implemented or deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test laboratory and / or a test scenario where a wired and / or wireless communication network is not deployed (e.g., under test) to perform tests on one or more components. The one or more simulation devices can be test equipment. The simulation device can transmit and / or receive data using direct RF coupling and / or wireless communication via RF circuitry (e.g., the circuitry may include one or more antennas).

[0069] To enable a range of devices with varying capabilities and requirements to effectively utilize the spectrum, control signaling has been made forward compatible in NR. For downlink (DL) or uplink (UL) scheduling, among other reasons, the WTRU can monitor PDCCH candidates in the search space located within a control resource set (CORESET). The WTRU can be configured with multiple CORESETs in a given carrier, for example, in different frequency portions of the carrier or in different symbols of a time slot. PDCCH candidates can be defined as a set of New Radio Control Channel Elements (NR-CCEs), which is itself a set of New Radio Resource Element Groups (NR-REGs). An NR-REG can be defined as a resource block (RB) during an OFDM symbol or a radio frame. NR-PDCCHs can be mapped continuously or discontinuously in frequency. The terms NR-PDCCH and PDCCH are used interchangeably here.

[0070] A WTRU can attempt to detect and decode (i.e., by using blind detection) the downlink control information (DCI) intended for that WTRU within PDCCH candidates. PDCCH candidates comprise a set of NR-CCEs. Such PDCCH candidates can reside within a search space configured for a specific WTRU. This search space can refer to the set of NR-CCE locations within which the WTRU can find its PDCCH. The search space can be shared by all WTRUs in a Transmit / Receive Point (TRP) or cell, shared by a group of WTRUs in a TRP / cell, or specific to the WTRU. Conversely, the search space configured for a WTRU can reside within multiple control resource sets (CORESETs) configured for that WTRU. The search space and / or CORESETs can be associated with a monitoring period.

[0071] To ensure that the WTRU can determine whether any of its PDCCH candidates has a DCI, there may be a limit to how many PDCCH candidates the WTRU must monitor at any given time. For example, the WTRU may have a maximum number of PDCCH candidates in a time slot. In another example, the WTRU may have a maximum number of NR-CCEs to which all PDCCH candidates in a time slot can be mapped. The maximum number of NR-CCEs to which all PDCCH candidates in a time slot can be mapped can be a function of the CORESET precoder granularity parameter provided by higher-layer signaling.

[0072] The PDCCH candidate set can be associated with at least one of the following: search space, CORSET, time element, aggregation level, DCI format, component carrier (CC), and / or bandwidth portion (BWP). When the PDCCH candidate set is associated with a search space, the maximum number of PDCCH candidates can further depend on the search space type (e.g., public, group-public, or WTRU-specific search space). When the candidate set is associated with a time element, the WTRU can monitor up to a maximum number of PDCCH candidates per symbol (or symbol group), or per slot (or slot group), or per subframe (or subframe group), or per TTI. This time element can depend on the subcarrier size (SCS) or can be defined relative to the default SCS. In one example, the WTRU can monitor up to a maximum number of PDCCH candidates for each absolute time period.

[0073] In the following text, the set of PDCCH candidates associated with the single parameter mentioned above may be referred to as the PDCCH candidate group, and the parameter mentioned above may be referred to as the grouping parameter.

[0074] The number of PDCCH candidates can be configured. A WTRU can be configured with a maximum number of PDCCH candidates per group. The maximum number of PDCCH candidates per group can depend on the WTRU's capabilities and can be fixed or configurable. This configuration can be implemented via DCI, MAC control element (CE), and / or higher-level signaling. The configuration can be WTRU-specific, group-common, or common to all WTRUs. For common configurations, the maximum number of PDCCH candidates can be included in the system information.

[0075] In one embodiment, the WTRU can be configured to operate with fewer than the maximum number of PDCCH candidates per group. In this case, the number of PDCCH candidates per group can be configured via DCI, MAC CE, and / or higher-level signaling. In another case, the number of PDCCH candidates per group is configured in a WTRU-specific manner.

[0076] The grouping parameters for applying the maximum number of PDCCH candidates can differ from those for applying a WTRU-specific number of PDCCH candidates. For example, the maximum number of PDCCH candidates can be applied to a time slot, while a WTRU-specific number of PDCCH candidates can be configured according to a CORESET. Thus, each of the n CORESETs located within a time slot can have a WTRU-specific number of PDCCH candidates. As described above, the configuration of each group's (maximum) number of PDCCH candidates can be done explicitly. Alternatively, this configuration can be done implicitly through a function that depends on another WTRU configuration. This function can depend on at least one of the following: the number of configured CORESETs, the number of configured search spaces, the number of configured or activated CCs, the number of configured or activated BWPs, operation BWs (which may be aggregated on all CCs and / or BWPs), or SCSs. For example, the number of PDCCH candidates in a CC or BWP can depend on the SCS. In another example, the number of PDCCH candidates in a time slot can depend on the number of different SCSs that the WTRU can monitor in that time slot. In another example, the function used to determine the number of PDCCH candidates may depend on the number of CCEs to which the aggregate set of all PDCCH candidates is mapped.

[0077] When configured with one or more values ​​for the number of PDCCH candidates per group, there may be situations where all values ​​are not aligned. For example, a WTRU can be configured to have X PDCCH candidates per slot and Y PDCCH candidates per CORESET. In a slot, there can be n CORESETs, and it is possible for Y to be n times greater than X (i.e., nY > X). In this case, prioritization and scaling are required.

[0078] The WTRU can receive a priority list of grouping parameters. In this case, the number of PDCCH candidates in the first group with the highest priority can lead to scaling the actual number of PDCCH candidates in the second group with lower priority. For example, the number of PDCCH candidates per slot can have the highest priority, and the number of any other PDCCH candidates may need to be scaled to ensure that the WTRU does not need to monitor more PDCCH candidates per slot than configured. In the CORESET example above, the WTRU can be configured to have up to X PDCCH candidates per slot and up to Y PDCCH candidates per CORESET. When the WTRU has n CORESETs in a slot and n times Y is greater than X (i.e., nY > X), the WTRU can scale the number of PDCCH candidates per CORESET.

[0079] In embodiments where the WTRU is configured with a single value for PDCCH candidates (i.e., for a single grouping parameter), the WTRU can then distribute the PDCCH candidates across a separate set of grouping parameters. For example, the WTRU may have a number of PDCCH candidates per slot and may receive explicit instructions on how to extend those candidates to the CORESET present within the slot.

[0080] In one embodiment, the WTRU can implicitly determine the distribution of PDCCH candidates based on a set of grouping parameters. It should be noted that this distribution need not be uniform. The distribution of PDCCH candidates can be a function of at least one of the following: time instance, duration, number of monitored cores in a time unit, number of core symbol numbers, type of core in the time unit, number of PRBs for the core, period of the core within the time slot, number of search spaces, search space type, aggregation level, number of active or configured CCs, number of active or configured BWPs, BW size of CCs / BWPs / sum of BWs of multiple (e.g., active) CCs / BWPs, SCS of CCs / BWPs, DCI type, service type, and / or DRX status. When the distribution of PDCCH candidates is a function of time instance, the WTRU can determine the number of PDCCH candidates depending on the time slot index. When the distribution of PDCCH candidates is a function of time duration, the WTRU can determine the number of PDCCH candidates depending on the time slot duration. When the distribution of PDCCH candidates is a function of the number of CORESETs monitored in a time unit, the number of PDCCH candidates per CORESET can depend on the number of CORESETs in the time slot. This can be for each CC or BWP, or for all CCs or BWPs. When the distribution of PDCCH candidates is a function of the number of symbols in a CORESET, the number of symbols in a CORESET can determine the number of PDCCH candidates within that CORESET.

[0081] When the distribution of PDCCH candidates is a function of the CORESET type in a time unit, the number of PDCCH candidates for each CORESET can depend on the parameters of that CORESET and the parameters of other CORESETs within the time slot. In this case, the parameters can be Quasi-Co-Location with Reference Signal (QCL). Therefore, depending on the RS QCL with respect to the CORESET and any other CORESET within the time slot, the WTRU can determine the number of PDCCH candidates. This allows for the allocation of a different number of PDCCH candidates for each beam that the WTRU may be monitoring. In this case, transmissions on a beam can be tied to a specific CORESET, and depending on the number of beams that can be supported in the time slot, the WTRU can determine the number of PDCCH candidates for each beam (i.e., each CORESET), which may vary.

[0082] When the distribution of PDCCH candidates is a function of the number of PRBs used for a CORESET, a CORESET spanning more PRBs can be assigned more PDCCH candidates. When the distribution of PDCCH candidates is a function of the period of a CORESET within a time slot, a CORESET for non-time slot scheduling can exist in multiple instances within a time slot. The number of instances can determine (e.g., the number of PDCCH candidates per instance). When the distribution of PDCCH candidates is a function of the number of search spaces, the number of search spaces within a CORESET can determine the number of PDCCH candidates within that CORESET. When the distribution of PDCCH candidates is a function of the search space type, a common search space can have fewer candidates than a group common search space or a WTRU-specific search space. When the distribution of PDCCH candidates is a function of the aggregation level, a search space can have only candidates in a subset of the aggregation level, and this subset can determine the number of PDCCH candidates. When the distribution of PDCCH candidates is a function of the number of active or configured CCs, each CC within a time slot can have a subset of all available PDCCH candidates, depending on the number of active CCs. The distribution of PDCCH candidates within CC can follow the rules described in this paper.

[0083] When the distribution of PDCCH candidates is a function of the number of active or configured BWPs, each BWP within a time slot may have a subset of all available PDCCH candidates, depending on the number of active BWPs. The distribution of PDCCH candidates within a BWP may follow the rules described herein. When the distribution of PDCCH candidates is a function of the BW size of a BWP or CC, or the sum of the BWs of multiple (e.g., active) CCs or BWPs, a larger CC can serve more WTRUs, and more PDCCH candidates can be assigned to that CC to mitigate the probability of blocking. When the distribution of PDCCH candidates is a function of the SCS of a CC or BWP, a larger SCS may result in fewer PDCCH candidates being assigned to that CC or BWP. In one example, a WTRU configured with multiple CCs / BWPs having different SCSs can determine the total number of PDCCH candidates per CC / BWP based on a reference SCS. In another example, a WTRU with multiple CC / BWPs configured with different SCSs can assume that the PDCCH candidates are distributed in such a way that they are a function of the SCS of each CC / BWP and / or a function of the entire set of SCSs configured for that WTRU.

[0084] When the distribution of PDCCH candidates is a function of the DCI type, some DCI transmissions can be repeated (e.g., in slots within one or more search spaces, or in one or more CORESETs). This can increase the reliability of PDCCH reception. In this case, the detection of such DCIs may require a combination of multiple PDCCH blind detections. Therefore, supporting this DCI type may affect the number of PDCCH candidates within a slot. When the distribution of PDCCH candidates is a function of the service type, PDCCH candidates can be associated with the service type. In one example, the number of PDCCH candidates associated with a slot, CORESET, or search space can be affected depending on whether it is available for eMBB and / or URLLC. When the distribution of PDCCH candidates is a function of the DRX state, the DRX state can affect the number of PDCCH candidates per group or per group parameter. For example, the DRX state can be bound to a limit on the number of PDCCH candidates for a particular aggregation level while ensuring a fixed number of PDCCH candidates for another aggregation level.

[0085] The distribution of PDCCH candidates can be a function of the CCE mapping. For example, the total number of PDCCH candidates can depend on the total number of CCEs used for all PDCCH candidates. In this case, the overlap of CCEs for different candidates, or the use of candidates with fewer CCEs, can result in a larger total number of PDCCH candidates.

[0086] When there is an uneven distribution of PDCCH candidates across a set of packet parameters, priorities can be assigned. For example, a CORESET can have a higher priority (e.g., if it is associated with a higher priority transmission) and therefore can be assigned a larger number of PDCCH candidates than a CORESET associated with a lower priority. In another example, a search space within a CORESET can have a higher priority than another search space within the same CORESET and therefore can be assigned more PDCCH candidates.

[0087] In one embodiment, a set of PDCCH candidates associated with grouping parameters can be assigned to the WTRU, but the WTRU may have to reduce the number of PDCCH candidates (e.g., due to conflicts of multiple grouping parameters within an allowed time period). For example, the WTRU may be configured with a number of PDCCH candidates per search space and a maximum number of PDCCH candidates per time slot. In the case of multiple search spaces conflicting in a time slot, the WTRU may have to reduce the number of PDCCH candidates in at least one search space. Each PDCCH candidate within a group may have an index. For cases where the WTRU can attempt blind detection of m PDCCH candidates within a group, the m candidates with the highest (or lowest) index can be used. Valid PDCCH candidates can be determined as a function of at least one of the following: group size, the value m, cell (or TRP) ID, WTRUID, SCS, BWPID, CC ID, and / or a factor of the grouping parameters (e.g., for search space grouping parameters, this factor may be the aggregation level).

[0088] The WTRU can determine the maximum number of PDCCH candidates for all groups that accommodate the first grouping parameter. Then, given the maximum number of PDCCH candidates based on the second grouping parameter, the WTRU can use a pruning function to reduce the number of PDCCH candidates in the groups associated with the first grouping parameter. For example, the WTRU can have n CORESETs in a time slot, each CORESET can be configured with Y PDCCH candidates, while a time slot can have a maximum of X PDCCH candidates. If n multiplied by y is greater than X (i.e., nY > X), the WTRU can use the pruning function to reduce the number of candidates per CORESET.

[0089] In another example, the WTRU can be configured with n CORESETs in a time slot. Each CORESET can be configured with Y PDCCH candidates. A time slot can have a maximum number of CCEs to which a PDCCH candidate can be mapped. PDCCH candidates can be mapped to such CCEs (e.g., where the maximum number of such CCEs can be used to reduce channel estimation complexity). If the sum of all CCEs for the nY PDCCH candidates exceeds the maximum configuration value, the WTRU can use a pruning function to reduce the number of candidates for at least one CORESET.

[0090] In another example, PDCCH candidates can be pruned to achieve a maximum number of PDCCH candidates per slot and a maximum number of CCEs used per PDCCH candidate per slot. This pruning algorithm can consider all search spaces existing in the slot and prune PDCCH candidates from one or more of these search spaces. The pruning algorithm can stop when the remaining number of candidates is less than the maximum value. For example, the pruning algorithm can stop when the sum of all PDCCH candidates that have not yet been pruned equals a certain value. Alternatively, the pruning algorithm can stop when the total number of required CCE estimates for the remaining PDCCH candidates is less than the maximum value. Note that the stopping criteria can be modified as needed without affecting the details of the pruning function. In this example, a randomized cyclic approach is used to remove some PDCCH candidates from each group (in this case, per search space or per CORESET). This randomized cyclic approach helps reduce the probability of PDCCH blocking by ensuring that the same candidates are not always pruned in every slot.

[0091] A WTRU configured with multiple PDCCH monitoring opportunities in a single time slot can determine a subset of PDCCH candidates for each search space. So that and and in It is a PDCCH candidate identifier. Y is the maximum number of PDCCH candidates that the WTRU is configured to monitor for CORESET p and aggregation level L, and X is the maximum number of blind decoding attempts. The WTRU can also trim the number of PDCCH candidates per search space such that the total number of CCEs for all PDCCH candidates within a time slot is less than or equal to Y. The value of Y can depend on the CORESET precoder granularity. For example, the value of Y can correspond to or be proportional to the product between the maximum number of CCEs Z (assuming the same precoder) and the CORESET precoder granularity (which, if the CORESET precoder granularity is in REG units, might be divided by the number of REGs per CCE). This method ensures that the channel estimation work undertaken by the WTRU remains within reasonable limits. The sum of CCEs used for all PDCCH candidates can be quantified to determine the required number of channel estimates. The WTRU can determine this number based on the CCEs used for PDCCH candidates and the CORESET precoder granularity.

[0092] WTRU can prune PDCCH candidates in a time slot by first setting up all monitored p and L. Then it loops through the monitored p and L, and in each iteration... The value is decreased by 1. The order of the loop is determined based on the following:

[0093]

[0094] Where Q = {q0, q1, ... q} Q Q is the set of all monitored resource sets (i.e., Q is a subset of P).

[0095] At the end of each pruning step within each loop, WTRU can determine whether criteria X and Y have been met. If so, pruning can be terminated, and the set of monitored PDCCH candidates can be determined.

[0096] refer to Figure 4 This illustrates method 400 of the pruning algorithm described herein. Method 400 begins at step 410, where the order of the WTRU search space is randomized, and an index is assigned to each search space. For the search space of the first index (step 420), at step 430, it is determined whether the total number of PDCCHs is higher than a threshold. Alternatively, step 430 may include determining whether the total number of CCE estimates is higher than a threshold. If, in either case, the threshold of step 430 is not exceeded, the pruning process stops at step 440. If the threshold is exceeded at step 430 (in other words, the total number of PDCCH candidates is higher than the threshold, or the total number of CCE estimates is higher than the threshold), then at step 450, a PDCCH candidate is removed from the set of PDCCH candidates in the search space of that index. At step 460, the process proceeds to the search space of the next index, and step 430 is repeated.

[0097] To further randomize the pruning function, we can first randomize it. The elements within may be randomized based on at least one of the following: WTRU ID, RNTI, slot number, cell ID, carrier ID, SCS, or BWP ID.

[0098] In another example, the criteria associated with the maximum number of CCEs that all PDCCH candidates can map to can have a higher priority. In this case, the order of pruning at the aggregation level L can be determined to first reduce candidates with larger CCE footprints (e.g., WTRU can first prune candidates with higher aggregation levels).

[0099] Figure 2An example physical downlink control channel (PDCCH) candidate allocation is illustrated within a variable number of control resource sets (CORESETs) or search spaces per time slot. In this example, the WTRU can be configured with a maximum number of PDCCH candidates per time slot. The WTRU can be configured to have multiple CORESETs or search spaces, each with different monitoring times (possibly enabling time slot and non-time slot scheduling). The number of CORESETs or search spaces per time slot can vary. For the case of n CORESETs or search spaces within a time slot, the WTRU can assume that each CORESET or search space has floor(X / n) PDCCH candidates (assuming X PDCCH candidates per time slot). Alternatively or additionally, the number of PDCCH candidates per CORESET or search space may not be uniform and may depend on the type of CORESET or search space (e.g., based on the beam associated with that CORESET).

[0100] like Figure 2 As shown, the WTRU can monitor a variable number of CORESETs or search spaces per time slot (i.e., the monitoring period for each CORESET or search space is different). In this example, the WTRU can have a fixed number of PDCCH candidates per time slot. In this case, it might be necessary to allocate a fixed number of PDCCH candidates per time slot based on the number of CORESETs or search spaces in the time slot (and the possible types of CORESETs or search spaces). Figure 2 In the example shown, there are a maximum of 44 PDCCH candidates per time slot configured using one of the methods described above. In time slot n, 44 PDCCH candidates can be allocated such that the common search space (CSS) has a higher priority than the UE-specific search space (UESS 1), and UESS 1 has a higher priority than UESS 2. Therefore, in this example, in time slot n (and n+6), the WTRU determines that the total number of PDCCH candidates accommodating all monitored search spaces will exceed the maximum value. Thus, the WTRU discards some (e.g., all) PDCCH candidates from UESS2.

[0101] In other time slots, such as time slots n+1 and n+2, the total number of PDCCH candidates accommodating the monitored search space does not exceed the maximum value, and therefore the WTRU monitors all assigned PDCCH candidates. The exact number of PDCCH candidates per CORESET or search space can be determined as a function of: priority, the total number of PDCCH candidates to be shared, the number of CORESETs or search space types, the maximum number of PDCCH candidates per CORESET or search space (or per CORESET or search space type), etc., as described above. The selection of PDCCH candidates within a CORESET or search space can depend on the time slot number, WTRU ID, CORESET or search space type, or any other parameter as described herein.

[0102] In one embodiment, the WTRU can be configured to have a maximum number (e.g., X) of PDCCH candidates per time slot per carrier. Furthermore, the WTRU can be configured to have a number (e.g., Y) of PDCCH candidates per CORESET. For a time slot with n CORESETs, the number of PDCCH candidates per CORESET is Y, provided that n multiplied by Y is less than or equal to X (i.e., nY ≤ X); otherwise, it is floor(X / n).

[0103] In another embodiment, the WTRU may have a configured or fixed number of PDCCH candidates per time slot, and multiple active BWPs may be configured in that time slot. The PDCCH candidate distribution may be a function of the total number of BWPs, the BWP index, the BWP size, and the SCS of the BWPs. For example, the total number of PDCCH candidates may be unevenly divided into X, such that larger BWPs have more PDCCH candidates than smaller BWPs. Alternatively, the number of PDCCH candidates configured per time slot may be based on a reference SCS time slot size. Thus, a BWP with a larger SCS may have fewer PDCCH candidates for each time slot duration than another BWP with a smaller SCS.

[0104] In another embodiment, the WTRU may have a configured or fixed number of PDCCH candidates per time slot, and multiple CORESETs may be configured within a time slot. The PDCCH candidates may be assigned to the CORESETs present in the time slot in a uniform manner. The WTRU may also have a DRX mode operating at the sub-time slot level. For example, in a DRX state, the WTRU may monitor only a subset of all CORESETs in the time slot. In this case, the number of PDCCH candidates per CORESET may depend on the DRX state.

[0105] Figure 3Example PDCCH candidate allocations are shown for different discontinuous reception (DRX) states. Figure 3 As shown, WTRU can operate with a fixed number of PDCCH candidates per time slot. Figure 3 In the example shown, there are 44 PDCCH candidates per time slot. The WTRU can operate in different DRX states in each time slot, and each DRX state can reduce the number of CORESETs (or search spaces) that the WTRU monitors in a given time slot. Figure 3 In the example scenario shown, for slots in DRX state 1, the WTRU has 4 cores to monitor per slot, and therefore can be assumed to have 11 PDCCH candidates per core. The WTRU monitors 11 PDCCH candidates per slot because there are 4 cores, and therefore 44 PDCCH candidates are evenly distributed across the 4 cores. For slots in DRX state 2, the WTRU has 2 cores to monitor per slot, and therefore can determine 22 PDCCH candidates to monitor per core. For slots in DRX state 3, some slots have a single core, and the WTRU can subsequently determine to monitor all 44 PDCCH candidates in that core. In this DRX state, other slots have zero cores. However, given the constraint of a maximum of 44 PDCCH candidates per slot, these candidates may not be reassigned from slots without cores to slots with cores. However, in the case of multiple BWPs or CCs, it is possible for other BWPs or CCs to utilize unused PDCCH candidates in these time slots.

[0106] The WTRU can determine the number of PDCCH candidates based on previously received DCIs. The WTRU can detect and decode a first DCI, which can affect the number of PDCCH candidates for upcoming resource sets. For example, the WTRU can detect and decode a first DCI for data transmission in a time slot, and the WTRU can then adjust the number of PDCCH candidates it can blindly detect over the duration of that time slot.

[0107] In one implementation, the WTRU can be configured for both time-slot scheduling and non-time-slot scheduling. The WTRU can detect a DCI in a first PDCCH candidate location for transmission in a time slot (possibly the same time slot as the one transmitting the DCI). The scheduled data transmission may overlap with transmissions of other PDCCH candidates (e.g., temporally). In this case, the WTRU can reduce the number of PDCCH candidates used for blind detection, thereby eliminating PDCCH candidates overlapping with previously scheduled transmissions. This can reduce the complexity associated with simultaneous data reception and blind detection of other PDCCH candidates. An example of this is that the WTRU is configured with multiple CORESETs in a time slot and in different time instances. The WTRU can detect and decode a DCI in a first CORESET for transmission that temporally overlaps with a second CORESET. The WTRU can attempt blind detection of a reduced number of PDCCH candidates in the second CORESET (e.g., if the CORESET is in a frequency resource orthogonal to the data transmission).

[0108] In one embodiment, a WTRU can be scheduled for transmission on a subset of symbols in a time slot (possibly based on DCIs transmitted in the same time slot or DCIs transmitted in previous time slots). For any other PDCCH candidate packet parameters in a time slot with scheduled transmissions, the WTRU can reduce the number of PDCCH candidates. For example, a WTRU is scheduled for transmission on the first symbol set in a time slot, and the WTRU is also configured with more CORESETs within that time slot. In this case, the WTRU can reduce the number of PDCCH candidates in the remaining CORESETs of that time slot. This can reduce the complexity associated with simultaneous data processing and blind detection of other PDCCH candidates.

[0109] In these examples, if each CORESET has up to Y PDCCH candidates, when scheduled in the first CORESET (where data transmission occurs simultaneously with or in the same time slot as reception in the second CORESET), the WTRU can attempt blind detection on Z PDCCH candidates in the second CORESET, where Z < Y. This example can be extended to cases where the first DCI (e.g., by using time slot aggregation) schedules the WTRU across multiple time slots. In this case, the WTRU can change the number of PDCCH candidates in the valid set of time slots assigned by the scheduling.

[0110] In one implementation, the WTRU can detect and decode the DCI in the first PDCCH candidate, which indicates a slot-based scheduling assignment. The WTRU may not expect other DCIs to be used for non-slot-based transmissions occurring within the slots of the assigned assignment on that CC and / or BWP. The WTRU can therefore increase the number of PDCCH candidates for non-slot-based scheduling on any CC and / or BWP where no slot-based scheduling assignment exists.

[0111] The time between the DCI of the scheduled transmission and the transmission itself can also determine the number of other PDCCH candidates that the WTRU can attempt to blindly detect for that CC and / or BWP, or for other CCs and / or BWPs.

[0112] refer to Figure 5 A flowchart 500 of a method according to several aspects described herein is shown. Beginning at step 510, the WTRU considers all search spaces to be monitored in the time slot. At step 520, the WTRU ranks the search spaces by search space type. At step 530, the WTRU ranks the search spaces within the search space type by a configured priority order. Then, at step 540, the WTRU selects the highest priority search space. Then, at step 550, for the selected search space, it is determined whether the total number of PDCCHs exceeds a threshold. Alternatively, step 550 may include determining whether the total number of CCE estimates exceeds a threshold. If in either case the threshold of step 550 is exceeded, at least one PDCCH candidate is discarded from the search space at step 560. In one case, all potential PDCCH candidates may be discarded from the search space. If the threshold of step 550 is not exceeded, all remaining PDCCH candidates are retained in the search space at step 570. In step 580, the second-highest priority search space is selected, and in step 550, the process is repeated using the PDCCH candidates of the currently considered search space and the sum of all previously held PDCCH candidates of the previously considered (i.e., higher priority) search space.

[0113] Although the features and elements described above are in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. Furthermore, the methods described herein can be implemented in computer programs, software, or firmware embedded in a computer-readable medium and executed 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, buffer memory, semiconductor storage devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM discs and digital multipurpose discs (DVDs). The processor associated with the software can be used to implement a radio frequency transceiver used in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: Receive configuration information indicating multiple search spaces, the configuration information indicating a corresponding number of physical downlink control channel (PDCCH) candidates associated with each corresponding search space in the multiple search spaces, wherein the configuration information indicates that a first search space in the multiple search spaces is associated with a set of PDCCH candidates; Determine the maximum number of PDCCH candidates to be monitored in a time slot; Based on the following, a subset of the PDCCH candidate set is determined to be used for monitoring in the first search space within the time slot: The total number of configured PDCCH candidates associated with the search space in which the WTRU is configured for PDCCH monitoring in the time slot exceeds the maximum number of PDCCH candidates to be monitored in the time slot; as well as The first search space corresponds to the first type of search space; as well as At least one subset of the PDCCH candidates associated with the first search space is used to monitor at least one PDCCH transmission in the time slot.

2. The method according to claim 1, wherein, The maximum number of PDCCH candidates to be monitored in the time slot is determined based on the subcarrier size (SCS).

3. The method according to claim 1, wherein the first type of search space corresponds to a WTRU-specific search space.

4. The method according to claim 1, wherein, The subset of PDCCH candidates to be monitored is determined based on the priority associated with the first search space.

5. The method of claim 1, further comprising: The PDCCH candidate index is used to determine which PDCCH candidates in the PDCCH candidate set should be monitored in the time slot.

6. The method of claim 1, wherein the method further comprises: The at least one PDCCH transmission is received via at least one PDCCH candidate from the search space associated with the WTRU configured for PDCCH monitoring in the time slot.

7. The method according to claim 1, wherein, The first type of search space corresponds to the common search space.

8. A wireless transmit / receive unit (WTRU) including a processor and a memory, the processor and memory being configured to: Receive configuration information indicating multiple search spaces, the configuration information indicating a corresponding number of physical downlink control channel (PDCCH) candidates associated with each corresponding search space in the multiple search spaces, wherein the configuration information indicates that a first search space in the multiple search spaces is associated with a set of PDCCH candidates; Determine the maximum number of PDCCH candidates to be monitored in a time slot; Based on the following, a subset of the PDCCH candidate set is determined to be used for monitoring in the first search space within the time slot: The total number of configured PDCCH candidates associated with the search space in which the WTRU is configured for PDCCH monitoring in the time slot exceeds the maximum number of PDCCH candidates to be monitored in the time slot; as well as The first search space corresponds to the first type of search space; as well as At least one subset of the PDCCH candidates associated with the first search space is used to monitor at least one PDCCH transmission in the time slot.

9. The WTRU of claim 8, wherein the maximum number of PDCCH candidates to be monitored in the time slot is determined based on the subcarrier size (SCS).

10. The WTRU of claim 8, wherein the first type of search space corresponds to a WTRU-specific search space.

11. The WTRU of claim 8, wherein the processor and memory are configured to determine, based on a priority associated with the first search space, to use the first search space in the time slot to monitor a subset of the PDCCH candidate set.

12. The WTRU of claim 8, wherein the processor and memory are configured to determine, based on the PDCCH candidate index, which PDCCH candidates in the PDCCH candidate set are monitored in the time slot.

13. The WTRU of claim 8, wherein the processor and memory are further configured to: The at least one PDCCH transmission is received via at least one PDCCH candidate from the search space associated with the WTRU configured for PDCCH monitoring in the time slot.

14. The WTRU of claim 8, wherein the first type of search space corresponds to a common search space.

15. A wireless transmit / receive unit (WTRU) including a processor and a memory, the processor and memory being configured to: Receive configuration information indicating multiple search spaces, wherein the configuration information indicates that a first search space among the multiple search spaces is associated with a first number of PDCCH candidates, and a second search space among the multiple search spaces is associated with a second number of PDCCH candidates; Determine the maximum number of PDCCH candidates to be monitored in a time slot; Based on the fact that the total number of PDCCH candidates configured in the time slot exceeds the maximum number of PDCCH candidates to be monitored in the time slot, it is determined that the first search space will be used in the time slot to monitor the first number of PDCCH candidates, and the second search space will be used in the time slot to monitor the third number of PDCCH candidates, wherein the second number of PDCCH candidates is reduced to the third number of PDCCH candidates in the second search space in the time slot based on the second search space corresponding to the first type of search space; as well as At least one PDCCH transmission in the time slot is monitored via at least one search space in the search space monitored in the time slot.

16. The WTRU of claim 15, wherein the set of PDCCH candidates indicated in the configuration information is monitored based on the first search space corresponding to the second type of search space.

17. The WTRU of claim 15, wherein the maximum number of PDCCH candidates to be monitored in the time slot is determined based on the subcarrier size (SCS).

18. The WTRU of claim 15, wherein one of the first type of search space or the second type of search space corresponds to a common search space, and the other of the first type of search space or the second type of search space corresponds to a WTRU-specific search space.

19. The WTRU of claim 15, wherein the second number of PDCCH candidates associated with the second search space is further reduced to the third number of PDCCH candidates based on the priority associated with the second search space.

20. The WTRU of claim 15, wherein the processor and memory are configured to determine, based on the PDCCH candidate index, which PDCCH candidates correspond to the third number of PDCCH candidates.

21. A wireless transmit / receive unit (WTRU) including a processor and a memory, the processor and memory being configured to: When operating in the first discontinuous reception (DRX) state, a first number of control resource sets (CORESET) are monitored, wherein each CORESET has a different monitoring period; When operating in the second DRX state, a second number of CORESETs are monitored, each CORESET having a different monitoring period, wherein the second number of CORESETs is greater than the first number of CORESETs; Determine a fixed number of physical downlink control channel (PDCCH) candidates for each time slot; as well as Based on the number of CORESETs in the time slot, a fixed number of PDCCH candidates are assigned to each time slot.

22. The WTRU of claim 21, wherein the fixed number of PDCCH candidates is based on one or any combination of the following: priority, the total number of PDCCH candidates to be shared, the number of CORESET types, the number of search space types, or the maximum number of PDCCH candidates per CORESET search space.

23. The WTRU of claim 21, wherein the processor is further configured to: It operates under different discontinuous reception states in each time slot.

24. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: Receive configuration information indicating multiple search spaces, wherein the configuration information indicates a first number of search spaces to be monitored when operating in a first discontinuous reception (DRX) state and a second number of search spaces to be monitored when operating in a second DRX state. Identify and monitor one or more PDCCH candidates; At least one or more PDCCH candidates are used to monitor at least one PDCCH transmission.

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