Physical downlink control channel with code domain multiplexed discrete Fourier transform precoding

Abstract

A wireless transmit / receive unit (WTRU) is configured to: report WTRU capabilities for physical downlink control channel (PDCCH) decoding to a network, including the number and size of supported discrete Fourier transform (DFT) modules; and receiving the PDCCH configuration from the network as a search space and control resource set (CORESET) configuration, the search space and control resource set (CORESET) configuration having a spreading factor or orthogonal code length, a number of frequency resource groups (FRG) and an associated size, an indication of code domain multiplexing, and a CORESET format. The WTRU determines a resource group (RG) size and a number of RGs per control channel element (CCE) based on a configured spreading factor and an FRG size, and determines an association between the RGs and an orthogonal cover code (OCC) per FRG and an orthogonal frequency division multiplexing (OFDM) symbol based on the configured spreading factor or the like.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 399,813, filed on Aug. 22, 2022, the entire contents of which are incorporated herein by reference. Background of the Invention

[0003] Power amplifiers (PAs) are considered to be one of the units with the highest power consumption at a wireless transmit / receive unit (WTRU). There is an inverse relationship between PA efficiency (e.g., power - added efficiency (PAE) or power efficiency (PE)) and PA saturation power (P sat ) at the operating frequency. At higher frequency bands, especially when operating at carrier frequencies above 100 GHz and approaching the THz range, it will result in lower PA efficiency and lower saturation power at the output of the PA. For input signals that exhibit non - constant envelope characteristics (i.e., input signals with high peak - to - average power ratio (PAPR)), this problem is further exacerbated because the PA needs to back off from operating at the most efficient point at the maximum output power (i.e., PA saturation power).

[0004] Discrete Fourier transform (DFT) - spread orthogonal frequency - division multiplexing (DFT - s - OFDM) is a waveform adopted by 3GPP for the uplink of 4G LTE and 5G NR due to its single - carrier nature, characterized by a reduced PAPR compared to cyclic - prefix (CP) OFDM (collectively referred to as CP - OFDM), while retaining the advantages of its simple frequency - domain equalization and simple inter - symbol interference (ISI) mitigation. In the case of operating in a frequency range above the current 5G NR frequency range, the DFT - s - OFDM waveform is adopted for the downlink beyond 5G NR, which may be desirable for addressing challenges associated with coverage and energy / power efficiency at these frequency bands. Summary of the Invention

[0005] A WTRU is defined according to a configuration that reports to a network the WTRU capabilities for physical downlink control channel (PDCCH) decoding, including the number and size of supported discrete Fourier transform (DFT) modules; and receives from the network a PDCCH configuration as a search space and control resource set (CORESET) configuration, the search space and control resource set (CORESET) configuration having a spreading factor or orthogonal code length, number and associated size of frequency resource groups (FRGs), indication of code domain multiplexing, and CORESET format. The WTRU is configured to: determine a resource group (RG) size and number of RGs per control channel element (CCE) based on one or more of the configured spreading factor and FRG size; determine an association between an RG and an orthogonal cover code (OCC) per FRG and orthogonal frequency division multiplexing (OFDM) symbol based on the configured spreading factor, a preconfigured OCC list, and a preconfigured mapping (e.g., of the RG size to the OOC); and determine an RG allocation pattern (i.e., across OFDM symbols and FRGs) and CCE index corresponding to each PDCCH candidate based on an aggregation level, the spreading factor, the CORESET format, and a preconfigured hash function.

[0006] The WTRU capability report may further include a maximum supported number of PDCCH candidates and a maximum number of non-overlapping CCEs supported per serving cell per time slot. The WTRU may also be configured to: receive a CCE size, and wherein the determination of the RG size is also based on the CCE size; and determine the RG size of a CCE as a ratio between the configured FRG size and the configured spreading factor. Additionally, the WTRU may determine the number of RGs per CCE as a ratio between the configured CCE size and the determined RG size. The configuration may also determine a code domain multiplexing (CDM) RG set size and / or determine the aggregation level according to a maximum aggregation level indicated in the configured search space and a preconfigured hash function, wherein the preconfigured hash function is determined based on an equation.

[0007] The WTRU configuration may also include a CORESET format that indicates one or more of the number of OFDM symbols for DCI, the number of OFDM symbols for demodulation reference signals (DMRS), the total number of OFDM symbols for DCI and DMRS, the OFDM symbol index for DCI, and the OFDM symbol index for DMRS. The configuration may determine the CDM RG set size based on the spreading factor of the configuration, the CCE size, the FRG size, and the number of RGs per CCE. Additionally, the WTRU may determine the number of OCC-FRGs for each CDM RG set based on the RG size, spreading factor, FRG size, system bandwidth, and subcarrier spacing; determine the number of time resource element (TRE) blocks within each FRG based on the number of CDM RG sets per FRG and OFDM symbol and the CORESET format; and determine the number of TREs associated with each CDM RG set in the FRG as the product of the RG size, the spreading factor, and the ratio between the size of the inverse fast Fourier transform (IFFT) module and the size of the DFT module, where the DFT module size corresponds to the FRG size and the IFFT module size corresponds to the number of subcarriers in an OFDM system with the system bandwidth and subcarrier spacing.

[0008] An operation method of a WTRU or a configuration of the WTRU may be provided for receiving, processing, and decoding a DFT-s-OFDM-based PDCCH, including the WTRU identifying an IDFT, a CDM RG of a PDCCH candidate, and despreading the RG based on network configuration and PDCCH processing parameters derived by the WTRU. The method may also include performing channel frequency selective diversity processing on the PDCCH through DFT despreading, code domain despreading, and / or frequency domain deinterleaving.

[0009] An operation method of a WTRU or a configuration of the WTRU may also be provided for determining a configuration for properly decoding a PDCCH candidate, where code domain multiplexing for a given CCE size, spreading factor, number and associated size of DFTs, time domain configuration for DCI and DMRS, frequency domain configuration, and time domain / frequency domain interleaving configuration is considered. The WTRU may also include using the number of resource groups per CCE, the number and associated size of DFTs, the time domain configuration for DCI and DMRS, the frequency domain configuration, and the time domain / frequency domain interleaving configuration.

[0010] A wireless transmit / receive unit (WTRU) may be configured to perform an operational method, wherein the WTRU receives first configuration information that indicates a control channel element (CCE) size, a spreading factor, and an indication of code domain multiplexing (CDM). The WTRU determines second configuration information based on the received first configuration information. The second configuration information may include a resource group (RG) size and a correspondence between the RG size of a CDM RG set and one or more orthogonal cover codes (OCCs). The WTRU may determine a CDM RG set allocation pattern across one or more orthogonal frequency division multiplexing (OFDM) symbols (such as discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols) and one or more frequency resource groups (FRGs) based on the second configuration information. The WTRU may receive a PDCCH transmission and perform an inverse discrete Fourier transform (IDFT) on a plurality of FRGs and the OFDM / DFT-s-OFDM symbols associated with the PDCCH transmission. The IDFT may be based on the CDM RG set allocation pattern and / or other parameters. The WTRU despreads the RG set corresponding to the PDCCH transmission. The despreading process may be based on the correspondence between the RG and the OCC per CDM RG set and / or other parameters. The WTRU further decodes downlink control information (DCI) in the PDCCH transmission based on the despread RG set. The first configuration information is contemplated to be static, or at least semi-static. The second configuration information may include a dynamic adaptation of the configuration for decoding the DCI in the PDCCH transmission.

[0011] The WTRU may also be configured to demodulate the OFDM / DFT-s-OFDM symbols received via one or more RGs associated with the PDCCH transmission to determine DL resource scheduling information. The WTRU may also receive a physical downlink shared channel (PDSCH) transmission based on the DL resource scheduling information. The first configuration information may include a search space configuration or a control resource set (CORESET) format. The first configuration information may include the number and size of one or more frequency resource groups (FRGs). The one or more FRGs may be associated with a single DFT module. The second configuration information may include the number of RGs per control channel element (CCE) and a plurality of CDM RG sets. The WTRU may further determine the second configuration information based on the correspondence between the RG and the OCC per CDM RG set, a preconfigured OCC list, and a preconfigured mapping of the RG size to the OCC. The RG per CDM RG set may be associated with DFT-s-OFDM symbols spanning the FRG.

[0012] The WTRU may also be configured to determine a CCE index for each PDCCH candidate for the PDCCH transmission based on an aggregation level and a preconfigured hashing function. The WTRU may also perform an IDFT on the plurality of FRGs and the OFDM / DFT-s-OFDM symbols associated with the PDCCH transmission based on the determined CCE index, the number of RGs per CCE, and the CDM RG set allocation pattern. The WTRU may also be configured to demodulate the OFDM / DFT-s-OFDM symbols received over all the RGs associated with the PDCCH transmission; detect a DCI format associated with the PDCCH transmission; and decode the DCI based on the detected DCI format. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1A is a system diagram illustrating an example communication system in which one or more of the disclosed embodiments may be implemented.

[0014] Figure 1B is an illustration of an example wireless transmit / receive unit (WTRU) that may be used within the Figure 1A illustrated communication system, according to an embodiment.

[0015] Figure 1C is an illustration of an example radio access network (RAN) and an example core network (CN) that may be used within the Figure 1A illustrated communication system, according to an embodiment.

[0016] Figure 1D is an illustration of another example RAN and another example CN that may be used within the Figure 1A illustrated communication system, according to an embodiment.

[0017] Figure 2 is a table showing a list of DCI formats supported in NR.

[0018] Figure 3A illustrates an example of a 2-symbol CORESET with CCEs and REGs.

[0019] Figure 3B illustrates examples of non-interleaved REG to CCE mapping and interleaved REG to CCE mapping.

[0020] Figure 3C illustrates examples of PDCCH candidates with aggregation levels (AL) 4, 8, and 16 in a 16-CCE CORESET for a non-interleaved configuration.

[0021] Figure 3DShows the EREG-to-RE mapping for the case of the normal cyclic prefix length in a frequency division duplex (FDD) system.

[0022] Figure 3E Shows an example of the symbols assigned to the DMRS for PUCCH format 3 and format 4 for the assigned symbols ∈ {10, 11, 12}.

[0023] Figure 3F Shows an example of the architecture for generating PUCCH format 3 and format 4.

[0024] Figure 3G Shows an example of the relationship between the 3G peak power added efficiency and frequency of a power amplifier using silicon transistors (top) and GaN and GaA transistors (bottom).

[0025] Figure 3H Shows an example of the relationship between the saturated output power and frequency.

[0026] Figure 4 Is a table showing the DM-RS positions for PUCCH format 3 and format 4.

[0027] Figure 5A Shows an example of a CORESET with dedicated DMRS symbols.

[0028] Figure 5B Shows an example of the physical layer processing of the PDCCH for DFT pre-coding with dedicated DMRS symbols.

[0029] Figure 5C Shows an example of the DMRS mapping in a 6-symbol CORESET with different starting symbols, length according to the number of consecutive DMRS symbols, number of additional DMRS symbols, and frequency domain allocation configuration.

[0030] Figure 5D Shows an example of the configuration with different CCE sizes and allocation patterns (short / long).

[0031] Figure 5E Shows an example of DFT pre-coding using one or more DFT pre-coders.

[0032] Figure 5F Shows an example of CCE multiplexing based on the number of PRBs assigned in an OFDM symbol and the CCE size.

[0033] Figure 5G Shows an example of CCE multiplexing in both the time domain and the frequency domain.

[0034] Figure 5H Shows an example of CCE multiplexing in the code domain.

[0035] Figure 5I Shows an example of the RG to CCE mapping based on the DFT size and the CCE multiplexing pattern.

[0036] Figure 5J Shows an example of RG interleaving in the time domain / frequency domain.

[0037] Figure 5K Shows an example of a 2-symbol CORESET with continuous and discontinuous PRB allocations.

[0038] Figure 5L Shows examples of 2-symbol and 4-symbol CORESETS with discontinuous PRB allocations and different types of RG interleaving.

[0039] Figure 5M Shows an example of an RG mapping using code domain multiplexing with a time domain interleaving configuration.

[0040] Figure 5N Shows an example of an RG mapping using code domain multiplexing with a frequency domain interleaving configuration.

[0041] Figure 5O Shows an example of an RG mapping using code domain multiplexing with time domain and frequency domain interleaving configurations.

[0042] Figure 6 Is a flowchart exemplifying an example of WTRU actions for determining a configuration for proper decoding of PDCCH candidates considering code domain multiplexing (CDM).

[0043] Figure 7 Is a flowchart exemplifying another example of WTRU actions for determining a configuration for proper decoding of PDCCH candidates considering code domain multiplexing (CDM).

[0044] Figure 8 Is a flowchart exemplifying the technical implementation of WTRU actions for determining a configuration for proper decoding of PDCCH candidates considering code domain multiplexing (CDM).

[0045] Figure 9 Is a flowchart exemplifying an example of WTRU actions for determining a configuration for proper decoding of PDCCH candidates considering code domain multiplexing (CDM).

[0046] Figure 10 Is a flowchart exemplifying another example of WTRU actions for determining a configuration for proper decoding of PDCCH candidates considering code domain multiplexing (CDM).

[0047] Figure 11It is a flowchart exemplifying another example of a WTRU action for determining a configuration for appropriately decoding PDCCH candidates considering code domain multiplexing (CDM).

[0048] Figure 12 It is a flowchart exemplifying WTRU actions for assisting dynamic adaptation of a configuration for appropriately decoding PDCCH candidates. Detailed implementation

[0049] Figure 1A It is a diagram exemplifying an example communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content such as voice, data, video, messaging, broadcasting, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multicarrier (FBMC), etc.

[0050] As Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104 / 113, a core network (CN) 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any one of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include user equipment (WTRU), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop computer, 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 device, 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 automation processing chain environment), a consumer electronic device, and a device operating on a commercial and / or industrial wireless network, etc. Any one of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0051] The communication system 100 may further include base stations 114a and / or base stations 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 communication networks such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be transceiver base stations (BTSs), Node Bs, evolved Node Bs, home Node Bs, home evolved Node Bs, gNBs, NR Node Bs, site controllers, access points (APs), and wireless routers, etc. Although each of the base stations 114a, 114b is depicted as a single element, it should be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0052] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of wireless services to a specific geographical area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0053] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) may be used to establish air interface 116.

[0054] More specifically, as noted above, communication system 100 may be a multi-access system and may employ 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, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish 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).

[0055] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as evolved UMTS terrestrial radio access (E-UTRA), which may use long term evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-A Pro to establish the air interface 116.

[0056] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may use new radio (NR) to establish the air interface 116.

[0057] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together using, for example, the dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions to / from multiple types of base stations (e.g., eNBs and gNBs).

[0058] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., wireless fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0059] Figure 1AThe base station 114b therein can be, for example, a wireless router, a home Node B, a home evolved Node B, or an access point, and can utilize any suitable RAT to facilitate wireless connections in local areas such as commercial premises, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for drones), and roads. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d can utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As Figure 1A shown, the base station 114b can have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0060] The RAN 104 / 113 can communicate with the CN 106 / 115, which can be any type of network configured to provide voice, data, applications, and / or voice over Internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data can have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements, etc. The CN 106 / 115 can provide call control, billing services, mobile location-based services, prepaid calls, Internet connections, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in Figure 1A it, it should be understood that the RAN 104 / 113 and / or the CN 106 / 115 can communicate directly or indirectly with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113 that can utilize NR radio technology, the CN 106 / 115 can also communicate with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0061] CN 106 / 115 may also act as a gateway for WTRU 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) in the TCP / IP Internet protocol suite. The network 112 may include a wired communication network and / or a wireless communication network owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, and the one or more RANs may employ the same RAT or a different RAT as the RAN 104 / 113.

[0062] Some or all of the WTRUs in the communication system 100, such as WTRU 102a, 102b, 102c, 102d, may include multi-mode capabilities (e.g., WTRU 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, Figure 1A the illustrated WTRU 102c may be configured to communicate with a base station 114a that may employ a cellular-based radio technology and with a base station 114b that may employ IEEE 802 radio technology.

[0063] Figure 1B is a system diagram illustrating an example WTRU 102. As Figure 1B shown, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138, among others. It should be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0064] The processor 118 can be a general - purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application - specific integrated circuit (ASIC), a field - programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), and a state machine, etc. The processor 118 can perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to a transceiver 120, and the transceiver can be coupled to a transmit / receive element 122. Although Figure 1B the processor 118 and the transceiver 120 are depicted as separate components, it should be understood that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0065] The transmit / receive element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via an air interface 116. For example, in one embodiment, the transmit / receive element 122 can be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 can be a transmitter / detector configured to transmit and / or receive signals such as IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 can be configured to transmit and / or receive both RF signals and optical signals. It should be understood that the transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0066] Although the transmit / receive element 122 is depicted as a single element in Figure 1B the WTRU 102 can include any number of transmit / receive elements 122. More specifically, the WTRU 102 can employ MIMO technology. Thus, in one embodiment, the WTRU 102 can include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via the air interface 116.

[0067] The transceiver 120 can be configured to modulate the signals to be transmitted by the transmit / receive element 122 and demodulate the signals received by the transmit / receive element 122. As noted above, the WTRU 102 can have multi - mode capabilities. For example, thus, the transceiver 120 can include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs (such as NR and IEEE 802.11).

[0068] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit) and may receive user input data therefrom. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information from any type of suitable memory (such as non-removable memory 130 and / or removable memory 132) and store data in any such type of suitable memory. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, and a secure digital (SD) memory card, among others. In other embodiments, the processor 118 may access information from a memory that is not physically located on the WTRU 102 (such as on a server or a home computer (not shown)) and store data in that memory.

[0069] The processor 118 may receive power from a power supply 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 may be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry cell battery packs (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, and fuel cells, among others.

[0070] 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 the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) via an air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be understood that the WTRU 102 may obtain location information by any suitable location determination method while remaining consistent with the embodiments.

[0071] The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connections. For example, the peripheral devices 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, Modules, FM radio units, digital music players, media players, video game player modules, Internet browsers, virtual reality and / or augmented reality (VR / AR) devices, 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; geographical location sensors; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0072] The WTRU 102 may include a full-duplex radio, for which the transmission and reception of some or all signals (e.g., associated with a specific subframe for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference via signal processing performed by hardware (e.g., chokes) or via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio, for which the transmission and reception of some or all signals (e.g., associated with a specific subframe for UL (e.g., for transmission) or downlink (e.g., for reception)).

[0073] Figure 1C FIG. is a system diagram of the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may communicate with the WTRU 102a, 102b, 102c via the air interface 116 using E-UTRA radio technology. The RAN 104 may also communicate with the CN 106.

[0074] The RAN 104 may include evolved Node Bs 160a, 160b, 160c, but it should be understood that the RAN 104 may include any number of evolved Node Bs while remaining consistent with the embodiment. Each of the evolved Node Bs 160a, 160b, 160c may include one or more transceivers for communicating with the WTRU 102a, 102b, 102c via the air interface 116. In one embodiment, the evolved Node Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0075] Each of evolved Node Bs 160a, 160b, 160c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, and scheduling of users in UL and / or DL, etc. As Figure 1C shown, the evolved Node Bs 160a, 160b, 160c may communicate with each other via the X2 interface.

[0076] 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. Although each of the foregoing elements is depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0077] The MME 162 may be connected to each of the evolved Node Bs 162a, 162b, 162c in the RAN 104 via the S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a specific serving gateway during the initial attachment of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide control plane functions for handover between the RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0078] The SGW 164 may be connected to each of the evolved Node Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions such as anchoring the user plane during handover between evolved Node Bs, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0079] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to a packet switched network such as the Internet 110 to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0080] CN 106 can facilitate communication with other networks. For example, CN 106 can provide the WTRUs 102a, 102b, 102c with access to a circuit-switched network, such as the PSTN 108, to facilitate communication between the WTRUs 102a, 102b, 102c and traditional landline communication devices. For example, CN 106 can include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 106 and the PSTN 108, or can communicate with such an IP gateway. Additionally, CN 106 can provide the WTRUs 102a, 102b, 102c with access to other networks 112, which can include other wired and / or wireless networks owned and / or operated by other service providers.

[0081] Although the WTRU is described in Figures 1A to 1D as a wireless terminal, it is contemplated that in some representative embodiments, such a terminal may (e.g., temporarily or permanently) use a wired communication interface with the communication network.

[0082] In a representative embodiment, the other network 112 can be a WLAN.

[0083] A WLAN in infrastructure basic service set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can have access to or an interface with a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or from the BSS. Traffic originating outside the BSS and destined for an STA can reach the AP and can be delivered to the STA. Traffic originating from an STA and destined for a target outside the BSS can be transmitted to the AP for delivery to the corresponding target. Traffic between STAs within the BSS can be transmitted through the AP. For example, where the source STA can transmit traffic to the AP, and the AP can deliver the traffic to the target STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be transmitted between a source STA and a target STA (e.g., directly between them) using direct link setup (DLS). In some representative embodiments, DLS can use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using independent BSS (IBSS) mode may not have an AP, and STAs within the IBSS or using the IBSS (e.g., all STAs in the IBSS) can communicate directly with each other. The IBSS communication mode may sometimes be referred to as an "ad hoc" communication mode in this document.

[0084] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP can send beacons on a fixed channel (such as the primary channel). The primary channel can be of a fixed width (e.g., 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 the STA to establish a connection with the AP. In some representative embodiments, for example, Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) can be implemented in the 802.11 system. For CSMA / CA, the STA (e.g., each STA) (including the AP) can listen to the primary channel. If the primary channel is listened to / detected and / or determined to be busy by a particular STA, that particular STA can back off. One STA (e.g., only one station) can transmit at any given time in a given BSS.

[0085] High Throughput (HT) STAs can communicate using a 40 MHz wide channel (e.g., via a combination of the primary 20 MHz channel and an adjacent or non - adjacent 20 MHz channel) to form a 40 MHz wide channel.

[0086] Very High Throughput (VHT) STAs can support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. The 40 MHz channel and / or 80 MHz channel can be formed by combining consecutive 20 MHz channels. The 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non - consecutive 80 MHz channels (which can be referred to as the 80 + 80 configuration). For the 80 + 80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. The Inverse Fast Fourier Transform (IFFT) processing and time - domain processing can be performed separately on each stream. These streams can be mapped to two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations for the 80 + 80 configuration described above can be reversed, and the combined data can be delivered to the Media Access Control (MAC).

[0087] 802.11af and 802.11ah support operation modes below 1 GHz. Compared to those used in 802.11n and 802.11ac, the channel operation bandwidth and carriers are reduced in 802.11af and 802.11ah. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV white space (TVWS) spectrum, and 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 may support meter type control / machine type communication, such as MTC devices in a macro coverage area. The MTC devices may have certain capabilities, such as limited capabilities, including supporting (e.g., only supporting) certain bandwidths and / or limited bandwidths. The MTC devices may include a battery with a battery life higher than a threshold (e.g., to maintain a very long battery life).

[0088] A WLAN system that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) includes channels that can be designated as a primary channel. The primary channel may have a bandwidth equal to the maximum common operation bandwidth supported by all STAs in a BSS. The bandwidth of the primary channel may be set and / or restricted by an STA (which supports the minimum bandwidth operation mode) from all STAs operating in the BSS. In an example of 802.11ah, for an STA that supports (e.g., only supports) the 1 MHz mode (e.g., an MTC type device), the primary channel may be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because an STA (only supporting the 1 MHz operation mode) is sending to the AP, the entire available frequency band may be considered busy even if most of the band remains idle and may be available.

[0089] In the United States, the available frequency band for 802.11ah is 902 MHz to 928 MHz. In Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz, depending on the country code.

[0090] Figure 1DFIG. 0 is a system diagram of RAN 113 and CN 115 according to an embodiment. As noted above, RAN 113 may employ NR radio technology to communicate with WTRU 102a, 102b, 102c via air interface 116. RAN 113 may also communicate with CN 115.

[0091] RAN 113 may include gNBs 180a, 180b, 180c, but it should be understood that while consistent with the embodiment, RAN 113 may include any number of gNBs. Each of gNBs 180a, 180b, 180c may include one or more transceivers for communicating with WTRU 102a, 102b, 102c via air interface 116. In one embodiment, gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, 180c. Thus, gNB 180a, for example, may use multiple antennas to transmit wireless signals to WTRU102a and / or receive wireless signals from that WTRU. In an embodiment, gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0092] WTRU 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with scalable parameter sets. For example, the OFDM symbol interval and / or the OFDM subcarrier interval may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRU 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of various lengths or scalable lengths (e.g., containing different numbers of OFDM symbols and / or having an absolute time length that continuously varies).

[0093] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in a stand-alone configuration and / or a non-stand-alone configuration. In the stand-alone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., such as evolved Node Bs 160a, 160b, and 160c). In the stand-alone configuration, WTRUs 102a, 102b, and 102c can use one or more of gNBs 180a, 180b, and 180c as a mobility anchor point. In the stand-alone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in an unlicensed band. In the non-stand-alone configuration, WTRUs 102a, 102b, and 102c can communicate / connect with gNBs 180a, 180b, and 180c while also communicating / connecting with another RAN (such as evolved Node Bs 160a, 160b, and 160c). For example, WTRUs 102a, 102b, and 102c can implement the DC principle to communicate with one or more gNBs 180a, 180b, and 180c and one or more evolved Node Bs 160a, 160b, and 160c substantially simultaneously. In the non-stand-alone configuration, evolved Node Bs 160a, 160b, and 160c can act as the mobility anchor for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0094] 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, scheduling of users in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, and routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, etc. As Figure 1D shown, gNBs 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0095] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possibly data networks (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0096] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selection of a particular SMF 183a, 183b, management of the registration area, termination of non-access stratum (NAS) signaling, and mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service utilized by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services that rely on ultra-reliable low latency (URLLC) access, services that rely on enhanced mobile broadband (eMBB) access, and / or services for machine type communication (MTC) access, etc. The AMF 162 may provide control plane functions for handover between the RAN 113 and other RANs (not shown) that employ other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0097] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, and Ethernet-based, etc.

[0098] UPF 184a and 184b can be connected to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N3 interface, and the one or more of them can provide access to a packet-switched network (such as the Internet 110) to the WTRUs 102a, 102b, and 102c to facilitate communication between the WTRUs 102a, 102b, and 102c and IP-enabled devices. UPF 184a and 184b can perform other functions, such as routing and forwarding packets, implementing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring, etc.

[0099] CN 115 can facilitate communication with other networks. For example, CN 115 can include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 115 and the PSTN 108, or can communicate with the IP gateway. Additionally, CN 115 can provide access to other networks 112 to the WTRUs 102a, 102b, and 102c, and the other networks can include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, and 102c can be connected to the DNs 185a and 185b via the N3 interface to the UPFs 184a and 184b and the N6 interface between the UPFs 184a and 184b and the local data networks (DNs) 185a and 185b.

[0100] In view of Figures 1A to 1D and Figures 1A to 1D In view of the corresponding descriptions, one or more functions or all functions of the functions described herein with respect to one or more of the following: WTRUs 102a - 102d, base stations 114a - 114b, evolved Node Bs 160a - 160c, MME 162, SGW 164, PGW 166, gNBs 180a - 180c, AMFs 182a - 182b, UPFs 184a - 184b, SMFs 183a - 183b, DNs 185a - 185b, and / or any other devices described herein can be performed by one or more emulation devices (not shown). The emulation device(s) can be one or more devices configured to mimic one or more functions or all functions of the functions described herein. For example, the emulation device(s) can be used to test other devices and / or simulate network and / or WTRU functions.

[0101] The simulation device can be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices can perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices can perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to another device for testing purposes and / or can perform tests using over-the-air wireless communication.

[0102] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test laboratory and / or in a test scenario in a non-deployed (e.g., test) wired and / or wireless communication network to implement tests of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via an RF circuit (e.g., which can include one or more antennas) can be used by the simulation device to transmit and / or receive data.

[0103] The downlink control information (DCI) for a WTRU in 3GPP NR can be carried by the physical downlink control channel (PDCCH). This corresponds to physical layer signaling from layer 1. Multiple DCIs with different formats can be configured for different purposes. Figure 2 A list of DCI formats supported in New Radio (NR) is shown.

[0104] The PDCCH carrying the DCI for a WTRU can be transmitted using resource elements belonging to a control resource set (CORESET). The CORESET defines the time-frequency region within the active bandwidth part of the WTRU where the WTRU can expect to receive its DCI. The WTRU can be configured with one or more CORESETs on its active bandwidth part. The CORESET can be a set of consecutive physical resource blocks (PRBs) or non-consecutive physical resource blocks (PRBs) configured with 6-PRB granularity, within which the WTRU attempts to perform blind decoding of its DCI. In the time domain, the CORESET spans 1, 2, or 3 consecutive OFDM symbols, and the exact duration can be configured for the WTRU via higher layer signaling such as SI or WTRU-specific RRC depending on whether the CORESET is a common CORESET or a WTRU-specific CORESET. Compared with the LTE PDCCH, the configurability of the CORESET enables efficient resource sharing between the DL control channel and the shared channel, thus achieving efficient layer 1 signaling overhead management.

[0105] The resource elements of the PDCCH can be defined according to control channel elements (CCEs). A CCE can be equivalent to six resource element groups (REGs), and these resource element groups can be equivalent to 72 resource elements. The PDCCH can use one or more CCEs. The number of CCEs allocated to the PDCCH can be defined by the aggregation level. A WTRU experiencing poor coverage is typically allocated a higher aggregation level to allow for increased channel decoding gain, i.e., a higher amount of redundancy.

[0106] The resource elements belonging to a CORESET can be organized into REGs. Six REGs can be used to generate a CCE. Within each REG, three resource elements can be allocated to the DMRS. Figure 3A An example of a CORESET format with CCE and REG allocations for two symbols is shown.

[0107] The REGs within a CORESET can be numbered in ascending order in a time-first manner, starting from 0 for the first OFDM symbol and the lowest-numbered resource block in the CORESET. In addition to having one or more frequency-continuous segments for the CORESET configuration itself, the PDCCH can also be mapped to the CORESET resources either continuously or discontinuously in frequency through an interleaved mapping of REGs to CCEs. Both non-interleaved (centralized) CCE-to-REG mapping and interleaved (distributed) CCE-to-REG mapping are possible. Each CORESET can be associated with a CCE-to-REG mapping. The interleaved CCE-to-REG mapping or non-interleaved CCE-to-REG mapping for a CORESET can be configured by higher-layer signaling, where the interleaving is in units of REG bundles. Figure 3B Examples of non-interleaved mapping and interleaved mapping are shown. In the non-interleaved mapping 300, a CCE can be generated from a bundle of six consecutively numbered REGs. The interleaved examples 302, 304 can provide frequency diversity since the REGs allocated to a CCE can be distributed across the CORESET. When using interleaved mapping, REG bundles (specified by reg-BundleSize) can be generated from two, three, or six REGs. For a 1- or 2-symbol CORESET format, REG bundle sizes 2 and 6 can be allowed; and for a 3-symbol CORESET format, REG bundle sizes 3 and 6 can be allowed. CCEs can be generated by grouping REG bundles. The interleaver depth (specified by interleaverSize) can be configured to determine the number of segments into which the CORESET bandwidth can be divided when interleaving is applied. The shift index (specified by shiftIndex) information element can be used to apply a cyclic shift to the interleaving pattern. The cyclic shift moves the CCE pattern upward, wrapping around from top to bottom.

[0108] PDCCH and DMRS may be transmitted using a single antenna port (p=2000). The WTRU may use DMRS to estimate the composite effect of both precoding and propagation channel. Depending on the higher layer configuration for each CORESET, the WTRU may assume that the same precoding in the frequency domain is used within a REG bundle (e.g., when precoderGranularity equals sameAsREG-bundle) or across all REGs within a set of contiguous resource blocks in a CORESET (e.g., when precoderGranularity equals allContiguousRBs).

[0109] In order to receive the DCI, the WTRU needs to perform blind decoding because it may not know the exact location of the PDCCH candidates used by the network. The PDCCH candidates that need to be monitored by the WTRU may be configured using a set of search spaces (SSs), where each SS is associated with a CORESET. In NR, there may be two types of search spaces: 1) a common search space (CSS) set, which is used to transmit DCI that is monitored by a group of WTRUs together; and 2) a WTRU-specific search space, such as a user-specific search space (USS), which is used to transmit DCI that is monitored by a specific WTRU.

[0110] The search space configuration indicates the WTRU time index in the form of symbols / slots to monitor to receive its DCI.Each search space may be configured with supported aggregation levels and the number of candidate PDCCH transmissions for each supported aggregation level. Figure 3C An example of PDCCH candidates with AL 4 (306), AL 8 (308) and AL 16 (310) in a CORESET consisting of 16 CCEs (for a non-interleaved configuration) is shown in FIG.

[0111] To decode the DCI, the WTRU performs blind decoding since it does not have explicit information about the DCI size, AL, and PDCCH candidates.The number of blind decodes (BD) may be a function of the number of ALs, the number of PDCCH candidates that need to be monitored for each AL, etc.

[0112] For the search space set associated with CORESET p, the search space set corresponding to the carrier indicator field value n is CI Time slot of active DL BWP of serving cell PDCCH candidates in the search space set The corresponding CCE index of aggregation level L is given by:

[0113]

[0114] For any common search space (CSS), For the USS, Y p,-1 = n RNTI ≠ 0, for p mod 3 = 0, A p = 39827, for p mod 3 = 1, A p = 39829, for p mod 3 = 2, A p = 39839, and D = 65537. i = 0,..., L-1. N CCE,p may be the number of CCEs in the CORESET p, numbered from 0 to N CCE,p -1. If the WTRU is configured with a carrier indicator field by the CrossCarrierSchedulingConfig of the serving cell on which it monitors the PDCCH, then n CI may be the carrier indicator field value; otherwise, including for any CSS, n CI = 0. Where may be the number of PDCCH candidates of the aggregation level L of the search space set s for which the WTRU is configured to monitor the serving cell corresponding to n CI For any CSS, For the USS, may be the maximum value of all configured n CI values of the CCE aggregation level L of the search space set s The RNTI used for n RNTI may be the C-RNTI.

[0115] To limit WTRU complexity and power consumption, there may be limits on the maximum number of PDCCH candidates per time slot and per serving cell and the maximum number of CCEs requiring channel estimation per time slot and per serving cell. These limits may be defined as a function of the subcarrier spacing.

[0116] The WTRU may be assigned / configured with different RNTIs. These RNTIs may be used to scramble the CRC bits that may be attached to the DCI payload during physical layer processing. For example, the SI-RNTI may be used / configured for a DCI containing information about system information (re)acquisition, the P-RNTI may be used for a DCI containing information about (e.g., scheduling) a paging message (e.g., reception), the C-RNTI may be used for a DCI containing information about (e.g., scheduling) WTRU-specific DL and UL data transmissions, etc. The WTRU may use the configured RNTI to descramble the CRC bits of the DCI to determine whether the DCI is intended for the WTRU.

[0117] In 3GPP LTE Release 11, an enhanced physical downlink control channel (EPDCCH) design can be considered to improve the capacity of the control channel by leveraging frequency-selective channel diversity, beamforming, and spatial reuse transmission techniques. One or more enhanced CCEs (ECCEs) can be used to transmit the EPDCCH, where an ECCE consists of 4 or 8 enhanced REGs (EREGs). A PRB pair can carry 16 EREGs, and each EREG consists of 9 REs. The 16 EREGs can be mapped to the REs in the PRB pair in a frequency-first and then time manner, ignoring the REs allocated to the DMRS. Then, the EREGs can be formed into REs corresponding to the index of the EREG, as Figure 3D shown. This mapping allows the resources of the EREGs to be evenly distributed over the time and frequency resources of the PRB pair. For different WTRU devices, the same or different sets of PRB pairs can be allocated for the EPDCCH, so the network can flexibly allocate the total amount of EPDCCH resources based on the load [9]. The position of the PRB pair in the frequency domain for the EPDCCH can be configured in a WTRU-specific manner via RRC signaling. Since the EPDCCH resources occupy a subset of the PDSCH resources, the network can utilize the same CSI when scheduling the EPDCCH and select favorable subbands and favorable precoders to achieve frequency-selective and beamforming gains.

[0118] Generally, EPDCCH multiplexing can be based on the form of frequency-domain or spatial-domain multiplexing. In addition, the EPDCCH must span the total duration of the subframe. Frequency-selective channel diversity can be achieved in the EPDCCH through the selection of the channel state of the PRB pair via centralized transmission, or through the distributed transmission of the EREGs of the ECCEs that constitute the EPDCCH.

[0119] In the NR uplink control channel, both the CP-OFDM waveform and the DFT-s-OFDM waveform can be used. CP-OFDM can be considered for downlink (DL) transmission, while both waveforms can be considered for uplink (UL) transmission to provide flexibility to the WTRU to improve its coverage in limited coverage scenarios.

[0120] In NR, transform precoding (e.g., DFT-based precoding) can be enabled by a set of data and / or reference symbols for each OFDM symbol to generate a DFT-s-OFDM waveform to generate a set of complex-valued symbols This set of complex-valued symbols can then be transmitted using the CP-OFDM waveform, where Indicates the number of subcarriers allocated for transmitting the set of data and / or reference symbols in a given OFDM symbol of a physical channel specified by the pc. The transform precoding operation can be defined as:

[0121]

[0122] And Can be defined according to the number of resource blocks (RBs) And the number of subcarriers per RB Where the number of RBs allocated for any uplink transmission using transform precoding should satisfy the following constraints:

[0123]

[0124] And α 2 , α 3 , α 5 Is a set of non - negative integers.

[0125] In NR, uplink control information (UCI) can be carried by a physical uplink control channel (PUCCH), and the physical uplink control channel (PUCCH) can use either the CP - OFDM waveform or the DFT - s - OFDM waveform based on the UCI format. For example, considering the CP - OFDM waveform, UCI format 0 and format 1 can be carried by the PUCCH and can have a payload size of 1 bit or 2 bits, while considering the DFT - s - OFDM waveform, UCI format 3 and format 4 can be carried by the PUCCH and can have a payload size greater than 2 bits. UCI format 2 can be carried by the CP - OFDM waveform and can have a payload size greater than 2 bits.

[0126] The UCI types reported in the PUCCH may include HARQ-ACK information, scheduling requests (SR), and channel state information (CSI). The WTRU may transmit one or two PUCCHs on the serving cell in different symbols within a time slot. The WTRU may have a dedicated PUCCH resource configuration provided by a PUCCH-ResourceSet in PUCCH-Config, or a common PUCCH resource configuration provided by an index to a table of resource sets preconfigured by pucch-ResourceCommon. PUCCH format 3 and format 4 may be transmitted on one or more PUCCH resources provided to the WTRU by a higher layer via a dedicated PUCCH resource configuration. The PUCCH resources may include any combination of the following parameters. The PUCCH resources may include a PUCCH resource index provided by pucch-ResourceId. The PUCCH resources may include the index of the first PRB before frequency hopping, or the index of the starting PRB in the case of no frequency hopping (e.g., if the WTRU is not provided by useInterlace PUCCH-PUSCH in BWP-UplinkDedicated). The PUCCH resources may include the index of the first PRB after frequency hopping, secondHopPRB (e.g., if the WTRU is not provided by useInterlace PUCCH-PUSCH in BWP-UplinkDedicated). The PUCCH resources may include an indication of in-slot frequency hopping, intraSlotFrequencyHopping (e.g., if the WTRU is not provided by useInterlace PUCCH-PUSCH in BWP-UplinkDedicated). The PUCCH resources may include the index of the first interlace, interlace0 (e.g., if the WTRU is provided by useInterlace PUCCH-PUSCH in BWP-UplinkDedicated). The PUCCH resources may include the index of the second interlace, interlace1 (e.g., if the WTRU is provided by useInterlace PUCCH-PUSCH in BWP-UplinkDedicated). The PUCCH resources may include the index of the RB set, rb-SetIndex (e.g., if the WTRU is provided by useInterlace PUCCH-PUSCH in BWP-UplinkDedicated). The PUCCH resources may include a configuration for the PUCCH format provided according to the format.

[0127] For PUCCH format 3, the PUCCH resource also includes the number of PRBs (provided by nrofPRBs), the number of symbols for PUCCH transmission (provided by nrofSymbols), and the first symbol for PUCCH transmission (provided by startingSymbolIndex). If the WTRU is provided by useInterlacePUCCH-PUSCH in BWP-UplinkDedicated and PUCCH-ResourceExt is provided, the PUCCH resource also includes the index of the second interlace, interlace1 (if provided); otherwise, if interlace1 is not provided, the PUCCH resource also includes the orthogonal cover code length occ-Length and the orthogonal cover code index occ-Index (if provided).

[0128] For PUCCH format 4, the PUCCH resource also includes the number of symbols for PUCCH transmission (provided by nrofSymbols), the orthogonal cover code length (provided by occ-Length), the orthogonal cover code index (provided by occ-Index), and the first symbol for PUCCH transmission (provided by startingSymbolIndex). For PUCCH transmission in FR2-2, the PUCCH resource may also include the number of PRBs (provided by nrofPRBs). Otherwise,

[0129] For a given PUCCH resource configuration, PUCCH formats 3 and 4 have a long transmission duration that can span from 4 to 14 OFDM symbols. PUCCH format 3 can support a maximum PUCCH payload size of 1706 bits, and if the WTRU is provided by useInterlacePUCCH-PUSCH and two interlaces can be configured, this PUCCH format can be configured with 1 to 16 RBs or 20 RBs. PUCCH format 4 can only be configured with multiple RBs in FR2-2; otherwise, it can only be configured with a single RB. If interleaved mapping is configured and only a single interlace is configured, for PUCCH format 3, block-by-block spreading using a spreading factor ∈ {1, 2, 4} determined by the higher layer parameter occ-Length should be applied. For PUCCH format 4, block-by-block spreading using a spreading factor ∈ {2, 4} determined by the higher layer parameter occ-Length should always be applied.

[0130] Both PUCCH format 3 and format 4 carry UCI symbols and demodulation reference signals (DMRS) to assist in demodulating the UCI symbols and can be transmitted on antenna port p = 2000. Dedicated OFDM symbols can be allocated for the DMRS, and for the cases with and without in-slot hopping and with and without additional DM-RS, Figure 4 shows the DMRS mapping / position for PUCCH format 3 and format 4. For PUCCH format 3 and format 4 with multiple allocated OFDM symbols ∈ {10, 11, 12}, Figure 3E shows an example allocation of resources for the PUCCH and the DMRS for the PUCCH. To further improve coverage and reliability, both PUCCH format 3 and format 4 can support cross-slot repetition commands {2, 4, 8}. Figure 3F shows an exemplary architecture for generating PUCCH format 3 or format 4.

[0131] Power amplifiers (PA) are generally considered to be the units with the highest power consumption at the transmitter. Therefore, PA efficiency can be an important metric, which is illustrated in Figure 3G as the relationship between the power added efficiency (PAE) of PAs fabricated using silicon transistors (e.g., SiGe) and semiconductor transistors (GaA and GaN) and the operating frequency [4]. It can be seen that the efficiency depends on the operating frequency and may show a downward trend as the operating frequency increases, i.e., the higher the frequency, the lower the PA efficiency. PAE can be defined as:

[0132]

[0133] where P out represents the output power delivered by the amplifier, P in represents the input power that can be handled by the amplifier (the maximum input power that can be handled by the PA can be determined based on the saturated output power of the PA), and P dc represents the DC power supplied to the amplifier. The PA output power can be much higher than the input power, i.e., the PA gain is very high, and PAE can be simplified to power efficiency (PE), which is defined as:

[0134]

[0135] According to the above equations (D) and (E), to maximize the average PA efficiency, the PA should operate at the maximum output power (i.e., the saturated power P sat) is driven. However, this may depend on the characteristics of the drive input signal, where signals with (near) constant envelope will be preferred. For signals that do not exhibit constant envelope characteristics, the PA operating point (e.g., the average power of the input signal) should be backed off, or (e.g., for a target average output power) the PA should be selected to have a saturation power (P sat ), which can be higher than the average power of the input signal by a certain value, and this value can be related to the PAPR of the input signal. However, in Figure 3H , where the relationship between the saturation power of the PA and the frequency for different technologies is shown, P sat may have an inverse relationship with the operating frequency, i.e., increasing the operating frequency will result in a decrease in the supported saturation power of the PA. Therefore, operating at a higher frequency band will result in a decrease in the saturation power of the PA, which in turn will lead to a decrease in the average output power of the PA, and the PAPR of the input signal may further exacerbate this situation.

[0136] The PAPR can be defined for discrete (e.g., OFDM) signals as the ratio of the maximum instantaneous (e.g., peak) power s(n) of the time-domain sequence to its average power, as follows:

[0137]

[0138] where represents the expected value or average value of the signal sequence. As discussed above, the PAPR of the signal waveform can be an important metric, for which a smaller value means more efficient operation of the power amplifier used to transmit the signal. In this sense, a signal exhibiting 0 dB PAPR may be optimal, which may be a characteristic of a constant envelope signal. Additionally, this metric may be particularly important at higher frequency bands, where power amplifier efficiency and saturation power may be crucial, as discussed.

[0139] DFT-s-OFDM can be a single-carrier waveform adopted by 3GPP for the uplink of 4G LTE and 5G NR wireless cellular standards. Due to its single-carrier nature, DFT-s-OFDM is characterized by a reduced peak-to-average power ratio (PAPR) compared to multi-carrier waveforms (such as CP-OFDM) that can be adopted for the downlink of 4G LTE and 5G NR wireless cellular standards. DFT-s-OFDM still retains the advantages of CP-OFDM, such as simple frequency-domain equalization and simple inter-symbol interference (ISI) mitigation. Adopting the DFT-s-OFDM waveform for the downlink beyond 5G NR at high frequencies may increase the complexity of the WTRU, but may be necessary for addressing challenges associated with coverage and energy / power efficiency at these frequency bands. Additionally, at high frequencies, BS coverage may be expected to be limited, and thus a higher BS deployment density may be expected, and the design complexity and cost requirements of the BS and WTRU may be comparable.

[0140] The efficiency of the power amplifier (PA) and the saturation power at the output of the PA can be considered. The PA is again considered to be one of the units with the highest power consumption at the transmitter, and the PA efficiency (e.g., power-added efficiency (PAE) or power efficiency (PE)) and the PA saturation power (P sat ) have a high dependence on the operating frequency. Since the PAE / PE / P sat may have a downward trend (i.e., an inverse relationship) with the operating frequency, operating at higher frequency bands is likely to result in lower PA efficiency and lower saturation power at the output of the PA. For input signals exhibiting non-constant envelope characteristics (i.e., input signals with high peak PAPR), this problem may be further exacerbated, as the PA needs to back off from operating at the optimal point with the highest efficiency at the maximum output power (i.e., the PA saturation power).

[0141] DFT-s-OFDM is a waveform adopted by 3GPP for the uplink of 4G LTE and 5G NR due to its single-carrier nature, characterized by a reduced PAPR compared to CP-OFDM while retaining the advantages of its simple frequency-domain equalization and simple inter-symbol interference (ISI) mitigation. In the case of operating in a frequency range higher than the current 5GNR frequency range, adopting the DFT-s-OFDM waveform for the downlink beyond 5G NR may be necessary for addressing challenges associated with coverage and energy / power efficiency at these frequency bands.

[0142] DFT-s-OFDM (e.g., transform precoding) can generate single-carrier waveform characteristics (i.e., in the time domain) only if subcarriers can be mapped to consecutive frequency positions, which limits the flexibility of DFT-s-OFDM to multiplex control information and data information in the frequency domain. For this reason, control channels and data channels in 5G NR may not be multiplexed in frequency, but are assigned different DFT-s-OFDM symbols so that the single-carrier property can be retained. This may also apply to some 5G NR reference signals (RS), such as DMRS, which do not allow multiplexing of data information in the same symbol.

[0143] CP-OFDM-based downlink control channel designs have been used in 4G LTE and 5G NR systems and have provided mechanisms for delivering control using multiple features (i.e., aggregation level, interleaving, time-frequency diversity utilization, simultaneous transmission of DMRS, and control of the same T-F resources at the resolution of PRB and OFDM symbols, etc.). The shift to higher frequencies has driven research on data and control transmission towards single-carrier waveforms.

[0144] Downlink control channels based on DFT-s-OFDM waveforms can have advantages similar to single-carrier waveforms, e.g., in terms of PA efficiency, and the flexibility provided by CP-OFDM-based downlink control channels in terms of frequency diversity, coverage, blocking probability, precoding, etc. In this regard, KPI requirements predicted for "beyond 5G NR" (e.g., in terms of spectral efficiency, network energy efficiency, and device power consumption) can also be considered.

[0145] For the purposes of the embodiments discussed herein, the following acronyms may be defined as follows. DFT-precoded DL control channel design, DFT-s-OFDM-based DL control channel design, DFT-s-OFDM waveform-based DL control channel design, and DFT-spread DL control channel design may be used interchangeably herein. DFT precoding, transform precoding may be used interchangeably herein. DFT, DFT module, and DFT precoder may be used interchangeably herein. gNB, eNB, network, and BS may be used interchangeably herein. PRB and RB may be used interchangeably. Modulated symbol and modulated data symbol may be used interchangeably herein. Symbol and OFDM symbol may be used interchangeably herein.

[0146] To maintain the single-carrier nature of DFT-s-OFDM signals with reduced PAPR characteristics compared to CP-OFDM, it is preferable to avoid or at least minimize the frequency-domain multiplexing of multiple signals. Therefore, in the design of DFT-precoded DL control channels, it may be desirable to use resource elements on dedicated OFDM symbols to transmit demodulation reference signals (DMRS). For example, the REs containing the DMRS of the PDCCH may be present in an OFDM symbol that may be different from the OFDM symbol containing the associated DL control information (DCI). Additionally, multi-symbol (e.g., more than 1 OFDM symbol) CORESET formats may include one or more symbols dedicated to DMRS transmission. For CORESET, different types of DMRS mapping may be configured, where the position of the OFDM symbol containing the DMRS symbol may be different (e.g., for the same number of OFDM symbols allocated for PDCCH and DMRS). Furthermore, one or more DMRS symbols may be allocated in front of the symbol containing control data (e.g., pre-loaded DMRS symbol) to start channel estimation as early as possible.

[0147] Figure 5A Some examples of DMRS mapping of DCI with associated DFT precoding on different OFDM symbols are given. For the common search space, any of the Figure 5B patterns / examples shown in may be used. Variations of these patterns / examples may be repeated one or more times within the continuous duration of one or more OFDM symbols, time slots, or subframes. Each pattern / example instance in the pattern / example instances may be associated with a different set of transmission beams / directions, where one set constitutes one or more beams / directions. Additionally, these pattern / example instances may be separated by one or more OFDM symbols, e.g., to leave time for beam switching. This method may also be applied to the overlapping dedicated search spaces of one or more WTRUs / devices.

[0148] Figure 5B An illustrative architecture for generating a DFT-precoded PDCCH with dedicated DMRS symbols is shown. In this architecture, the WTRU alternates between PDCCH and DMRS based on the CORESET configuration for PDCCH transmission on consecutive DFT-s-OFDM symbols. The example shown is for a 5-symbol CORESET dedicated to DMRS and 2 DFT-s-OFDM symbols.

[0149] For CORESET configuration, the WTRU may be configured with a DMRS configuration that includes one or more parameters. For example, a time domain allocation parameter that can be used to derive the position of the DMRS OFDM symbol within the CORESET. The CORESET may include one or more OFDM symbols that contain the DMRS. One or more allocation mappings may be configured taking into account the number of OFDM symbols in the CORESET and / or the respective positions of the DMRS symbols. The DM-RS configuration for the CORESET may vary with the number of symbols allocated for the PDCCH. The configuration parameters may include, for example, the symbol index of the symbol that contains the DMRS, where the symbol index may be relative to the starting symbol of the time slot that contains the associated CORESET, or relative to the starting symbol of the associated CORESET within the time slot. Alternatively, the symbol index of the first symbol that contains the DMRS has a plurality of additional positions (e.g., OFDM symbols), where the positions of the additional symbols relative to the first symbol may be pre-configured for the WTRU. The length may be configured according to the number of consecutive symbols that contain the DMRS (e.g., 2 symbols / 3 symbols, etc.).

[0150] Another parameter for CORESET configuration may include a frequency domain allocation parameter, which can be used to derive the position of the DMRS RE on the OFDM symbol that contains the DMRS in the frequency domain. One or more allocation mappings can be configured based on the number of REs / PRBs (e.g., density) and their positions in the allocated bandwidth (e.g., PRBs) of the CORESET. The configuration parameters can include, for example, the RE index and PRB index in one or more OFDM symbols that contain the DMRS. The same or different frequency domain mappings can be configured for different OFDM symbols within the CORESET. All the REs in the REs of each PRB associated with the allocated bandwidth of the CORESET can be used for DMRS mapping. A subset of the REs of each PRB associated with the allocated bandwidth of the CORESET can be used for DMRS mapping. In such cases, the other REs that may not be used for DMRS can be used for other purposes (e.g., data or control information). In one example, the RE index that contains the DMRS can be given in the configuration. Alternatively, different configuration mappings can be pre-configured with different fixed sets of REs in each PRB allocated for DMRS for a given CORESET configuration. For example, configuration type 1 can have 6 REs that use every other RE in each PRB allocated to the CORESET; configuration type 2 can have 4 REs in each PRB allocated to the CORESET (e.g., RE0, RE1, RE5, RE9, or RE0, RE3, RE6, RE9); configuration type 3 can have all the REs in each PRB allocated to the CORESET. Other configurations with different numbers of REs and positions can be configured. A subset of the PRBs within the bandwidth of the CORESET can be configured for DM-RS. In such cases, the PRB index can be given in the configuration. In the case where multiple symbols are allocated for DM-RS, the same frequency domain mapping pattern can be configured for all the symbols. Different types of frequency domain mapping patterns can be configured on different symbols. In this case, the DM-RS configuration can include the frequency domain mapping configuration applied to each DM-RS symbol.

[0151] Further parameters for CORESET configuration may include DMRS sequence design parameters, including any one of sequence type, initialization seed, cyclic shift, base sequence number, etc. Some of these parameters can be signaled explicitly or determined implicitly based on any one of the OFDM symbol number, slot number, number of allocated frequency resources, spreading sequence for the configuration of PDCCH, etc.

[0152] Other parameters for CORESET configuration may include modulation type, spreading factor and corresponding orthogonal sequence index, pre-coding configuration, number of DFT modules per CORESET, etc.

[0153] Figure 5C Several illustrative examples of DMRS mapping in a 6-symbol CORESET with different starting symbols, length according to the number of consecutive DMRS symbols, number of additional DMRS symbols, and frequency-domain allocation configuration are shown. Higher layer signaling (e.g., RRC or system information (e.g., MIB, SIB 1)) can be used to provide the DMRS configuration to the WTRU within a CORESET configuration (e.g., a part of ControlResourceSet or / and ControlResourceSetzero).

[0154] The CCE size can affect the DMRS mapping on dedicated OFDM symbols. The time-frequency resources of a CORESET can be organized into one or more CCEs containing DCI. In NR, in the case of an OFDM-based DL control channel design, a CCE can consist of 6 REGs (e.g., one REG can be equivalent to 12 REs, e.g., a total of 72 REs for one CCE), where in each REG, 3 REs can be allocated for DMRS and the remaining 54 REs are for DCI data. For a DFT-s-OFDM-based DL control channel design for allocating DMRS on dedicated OFDM symbols, one or more of the following can be used for the number of REs / PRBs allocated to a CCE. New terms / definitions can be used to replace CCE to distinguish it from the 3GPP Release 15 CCE that contains DMRS in the frequency domain. The same term "CCE" can be used in this document, but other terms can also be used. The expected number of modulated symbols carried by a DFT-s-OFDM-based CCE can be different from the number of modulated symbols carried by an existing OFDM-based CCE. Based on these potential differences, it may be appropriate to maintain the number of REs per CCE and the corresponding number of modulated symbols (e.g., a CCE consists of 54 REs). Additionally, reducing the number of REs per CCE and the corresponding number of modulated symbols (e.g., a CCE consists of 48 REs, equivalent to 4 RBs) may be applicable. Further, increasing the number of REs per CCE and the corresponding number of modulated symbols (e.g., a CCE consists of 60 REs, equivalent to 5 RBs) is possible.

[0155] The above-described embodiments for determining the number of REs per CCE can depend on several factors discussed below, including any constraints on the number of modulated symbols to be conveyed via the PDCCH, the reliability of the PDCCH, and the PDCCH multiplexing ability within any CORESET.

[0156] In the first option, in order to maintain the number of REs per CCE and the corresponding number of modulated symbols, a single CCE may require a fraction of the number of RBs (e.g., equivalent to 4.5 RBs). Thus, CCE multiplexing can be considered as part of determining the number of REs. For example, multiple CCEs (e.g., 2 aggregated / multiplexed CCEs) can occupy multiple frequency resources and OFDM symbols (e.g., 108 REs), which can be equivalent to an integer number of RBs (e.g., 9 RBs), corresponding to a fraction of the effective number of RBs per CCE (e.g., 9 / 2 = 4.5 RBs). The actual number of RBs can depend on the pattern of symbols allocated to the PDCCH and the number of multiplexed CCEs. For example, it can be considered to allocate 3 RBs and 4 OFDM symbols (e.g., including one OFDM symbol dedicated for DMRS for the PDCCH) to multiplex 2 CCEs.

[0157] The second option is to reduce the number of REs per CCE and the corresponding number of modulated symbols, which can correspond to a lower PDCCH capacity (i.e., reducing the number of unique information bits that can be conveyed via the PDCCH) or lower reliability (e.g., by considering a higher code rate or the availability of fewer resources for rate matching). The exact impact on the PDCCH capacity and / or reliability can depend on the degree of reduction of the allocated REs, and this impact can be mitigated by other techniques such as CCE aggregation.

[0158] The third option is to increase the number of REs per CCE and the corresponding number of modulated symbols, which can correspond to a higher PDCCH capacity (i.e., increasing the number of unique information bits that can be conveyed via the PDCCH) or higher reliability (e.g., by considering a lower code rate or the availability of more resources for rate matching). However, this may come at the cost of higher resource utilization and / or lower PDCCH multiplexing ability, which may be acceptable for the case where it is expected that at any given time a limited number (e.g., one or more) of WTRUs are served per beam for narrow beams at high frequencies. Thus, the pattern of symbols allocated for the PDCCH may need to be repeated in a timely manner to support beam switching (e.g., for the common search space), as discussed in the section of this document regarding demodulation reference signal (DMRS) multiplexing. At high frequencies, it is expected that the subcarrier spacing is greater than the currently supported value, resulting in a smaller OFDM symbol duration and subsequently a limited impact on the PDCCH decoding latency.

[0159] Another design consideration that may be considered for dedicating symbols to DMRS for PDCCH can be the pattern of symbols allocated to the PDCCH and the DMRS for the PDCCH, as discussed again regarding DMRS multiplexing. The allocation pattern can be classified as a short allocation pattern or a long allocation pattern. The short allocation pattern can be a case where a small number of OFDM symbols (e.g., 2 OFDM symbols) are allocated to the PDCCH and the DMRS for the PDCCH. This option can correspond to a high DMRS overhead (e.g., for the 2 OFDM symbol case, the overhead is 50%). The long allocation pattern can be a case where a relatively large number of OFDM symbols (e.g., 3 or more OFDM symbols) are allocated to the PDCCH and the DMRS for the PDCCH. This option can correspond to a low or high DMRS overhead based on the configuration of additional DMRS (e.g., for the 3 OFDM symbol case (where a single OFDM symbol is dedicated to DMRS), the overhead is ~33%).

[0160] In one example, the same (e.g., fixed) value of the CCE size or / and the allocation pattern can be used on all CORESETs of the WTRU. The WTRU can be pre-configured with the CCE size. Different CCE size values or / and allocation patterns can be configured for different CORESETs. In each CORESET configuration provided to the WTRU via, for example, RRC or SI signaling, the WTRU can be configured with the associated CCE size and allocation pattern.

[0161] Figure 5D Several examples with different configurations in terms of CCE size and short / long allocation pattern are shown. Figure 5D Part (a) of shows an example of the long allocation pattern, where 3 OFDM symbols are allocated for the CORESET, and one symbol (the second symbol) is dedicated to DMRS. In Figure 5D Part (a) of, 3 CCEs are multiplexed with each CCE of size 4 PRBs (48 REs) in the time domain (e.g., on different OFDM symbols), which can be an example of a reduced number of REs per CCE compared to the existing OFDM-based CCE design. Figure 5D Part (b) of shows an example of the short allocation pattern with a CCE size of 5 PRBs (e.g., where 2 OFDM symbols are allocated for the CORESET, and one symbol (the second symbol) is dedicated to DMRS), which can be an example of an increased number of REs per CCE compared to the existing OFDM-based CCE design. Figure 5DPart (c) shows another example of the short allocation mode (e.g., where 2 OFDM symbols are allocated for the CORESET, and one symbol (the second symbol) is dedicated to the DMRS), where two CCEs are multiplexed in the same OFDM symbol, and the size of each CCE is equivalent to 4.5 PRBs, which can be an example of maintaining the same number of REs per CCE compared to existing OFDM-based CCE designs.

[0162] CCE allocation and multiplexing may affect DFT pre-coding. For the CORESET, one or more DFTs may be used to apply transform pre-coding to a set of PDCCH modulated symbols, and (e.g., using consecutive or non-consecutive frequency resource allocation) map the output samples of the DFT pre-coding to the set of allocated REs, where the set of allocated REs is located on the set of OFDM symbols associated with the CORESET and is allocated for carrying DCI data. One or more DFTs may have a size (e.g., the number of DFT samples, which may be equal to the number of REs on which the samples of the DFT pre-coding can be mapped), and this size may be provided as a configuration parameter that indicates the same or different sizes of each DFT used in the same OFDM symbol and associated with the same CORESET. Figure 5E Examples of using multiple DFT pre-coders and a single DFT pre-coder on OFDM symbols associated with the same CORESET are shown. For a given number of PRBs, compared to a lower number (e.g., with a larger size) of DFTs as shown in part (b) of Figure 5D for example, Figure 5D a configuration with a higher number (e.g., with a smaller size) of DFTs as shown in part (a) of Figure 5D may have a higher PAPR. The configuration with a separate DFT pre-coder within an OFDM symbol as shown in part (a) of Figure 5D is referred to as a distributed DFT configuration, and the configuration with a single DFT pre-coder within an OFDM symbol on non-consecutive PRBs as shown in part (b) of

[0163] is referred to as a clustered DFT configuration in this document. The modulated symbols of one or more CCEs may belong to one or more PDCCHs addressed to one or more WTRUs.

[0164] Configuration information may be explicitly provided as a sequence of integers indicating the size of one or more DFTs, where the number of DFTs may be determined according to the length of the sequence. The number of DFTs may be explicitly provided as an integer, and the size applicable to all DFTs may be explicitly provided as another integer. Alternatively, the number and size of the DFTs may be implicitly derived based on a sequence of integers indicating the number of CCEs multiplexed within a subset of the frequency resources allocated in a CORESET and an OFDM symbol allocation pattern, where the size of each subset may also be determined according to the number of CCEs multiplexed for the indicated OFDM symbol allocation pattern and the size of each CCE.

[0165] The order of the subsets of frequency resources may be preconfigured or signaled to the WTRU as part of the CORESET configuration. The WTRU may assume that the first DFT precoder given in a list containing one or more DFT precoders may be used on a first set of REs allocated for the associated CORESET (e.g., starting from the lowest-indexed RE in the frequency domain), where the number of REs in the first set is equal to the DFT size of the first DFT precoder, and the second DFT precoder may be used on a second set of REs (e.g., starting from the first RE allocated to the CORESET, which is the last RE in the first set of REs determined for the first DFT precoder), where the number of REs in the second set is equal to the DFT size of the second DFT precoder, and so on.

[0166] The WTRU may be configured with the (e.g., default / fixed) size of the DFTs of one or more DFT precoders to be used on the OFDM symbols associated with a CORESET. The WTRU may determine the number of DFT precoders applied on an OFDM symbol by using the number of PRBs (e.g., REs) and the DFT size. For each DFT precoder, the WTRU may use the DFT size and the CCE size to determine the number of CCEs multiplexed in the time domain.

[0167] Subsequently, different CCE multiplexing schemes (e.g., time-domain multiplexing, frequency-domain multiplexing, and / or code-domain multiplexing) can be considered in the CORESET based on the configuration. The WTRU can be configured to consider only time-division multiplexing (e.g., using a single DFT over the allocated CORESET bandwidth), only frequency-division multiplexing (e.g., each CCE can be independently transformed and precoded), only code-division multiplexing (e.g., using a single DFT over the allocated CORESET bandwidth with an indication of code-division multiplexing and / or orthogonal code length), or a combination thereof. The multiplexing scheme considered can be explicitly and / or implicitly configured within the CORESET for one or more associated CCEs. The multiplexing pattern can be derived based on any one or more of the following: the number of DFTs, the CCE size, the DFT size, the number of PRBs allocated within the OFDM symbol, and / or the OFDM symbol allocation pattern (i.e., the number of OFDM symbols allocated for DCI data). The multiplexed CCEs can form one or more PDCCHs carrying one or more DCIs, which are intended for a single WTRU or more than one WTRU.

[0168] The WTRU can be provided with a list of one or more configurations, each associated with, for example, a DFT module or a subset of the allocated frequency resources associated with a single DFT module, where the size of the list can be used to indicate frequency-domain multiplexing. For example, if more than one configuration can be provided, and each configuration includes a parameter indicating whether time-division multiplexing or code-division multiplexing can be used for the subset of frequency resources associated with the corresponding DFT module. The WTRU can determine frequency-division multiplexing based on the received indication of the number of DFTs considered in the CORESET, and the WTRU can be provided with a global multiplexing option for all DFT modules within the CORESET as a single CORESET configuration parameter. The WTRU may have to blindly determine the time-division multiplexing and / or code-division multiplexing options associated with each DFT module in the configured CORESET. The WTRU can determine the number of CCEs multiplexed over the OFDM symbol in the time domain or code domain based on any one of the CCE size, the DFT size for the DFT precoder, and the OFDM symbol allocation pattern.

[0169] In the case of code-domain multiplexing, the WTRU can be configured with an orthogonal cover code (OCC) length. The orthogonal cover code length can depend on the number of multiplexed CCEs, and each CCE can be extended by one code from a preconfigured set of codes based on the determined length. Alternatively, (e.g., within the same time and frequency resources) the number of multiplexed CCEs can depend on the OCC length. The WTRU can be preconfigured or configured with a set of orthogonal cover codes, and the WTRU can use the set of orthogonal cover codes to extract the CCEs multiplexed in the code domain.

[0170] Figure 5F An example of time-domain CCE multiplexing in an OFDM symbol is shown, where the number of CCEs (e.g., the number of CCEs shown ∈ {3, 2, 1}) can be based on the number of PRBs allocated for the CORESET (e.g., an example with the number of RBs ∈ {15, 10, 5} shown), the CCE size (e.g., a size of 5 RBs per CCE is shown), and the OFDM symbol allocation pattern (e.g., two OFDM symbols are allocated, where one OFDM symbol is dedicated to DMRS for PDCCH). Figure 5G More examples are shown, where a combination of time-domain multiplexing and frequency-domain multiplexing (e.g., using different DFT precoders) can be considered. These examples consider the number of DFTs as 2, the CCE size of 5 RBs, the total number of 10 RBs per CORESET, and an OFDM symbol allocation pattern with 2 OFDM symbols ( Figure 5G part a) or 3 OFDM symbols ( Figure 5G part b) and one OFDM symbol dedicated to DMRS for PDCCH).

[0171] In the case of a multi-symbol CORESET, when more than one OFDM symbol can be allocated to transmit DCI data within the CORESET, the same or different configurations can be used in terms of the number of DFT precoders or / and the DFT size. In the case of different configurations on one or more OFDM symbols associated with the CORESET, one or more configurations associated with the one or more OFDM symbols can be provided to the WTRU.

[0172] Figure 5H Two examples of code-domain CCE multiplexing are shown. In Figure 5H part (a), two CCEs are multiplexed on the same time resource and frequency resource using an OCC length of 2 (e.g., the spreading factor or the number of OCC codes), while in Figure 5H part (b), four CCEs are multiplexed on the same time resource and frequency resource using an OCC length of 4. Each CCE can be extended by one code from a set of OCC codes of a given length. A larger OCC length increases the multiplexing capacity, but reduces the capacity available for each individual CCE (e.g., in terms of the number of modulated symbols that can be mapped). As shown in Figure 5H parts (a) and (b) of

[0173] The CCE composition can be defined according to one or more resource groups (RGs), where the term "RG" is used to distinguish from the term "REG" (e.g., in 3GPP 5G NR), and where DMRS can be multiplexed in the frequency domain. Additionally, the definition of a time resource element (TRE) can be introduced, where each TRE represents an IFFT output sample, and based on the relationship between the size of the DFT module and the size of the IFFT module, each DFT input sample can correspond to one or more TREs. Additionally, due to DFT pre-coding, each modulated symbol in the time domain can be spread across all the frequency resources (e.g., sub-carriers or REs) that can be assigned to a single DFT module. Thus, it can be assumed that each DFT module is associated with a single frequency resource group (FRG) spanning one or more sub-carriers (e.g., the FRG consists of consecutive or non-consecutive sub-carriers and one TRE). However, other terms can also be used to represent the definitions of RG, TRE, and / or FRG.

[0174] Each RG can carry a part or all of the modulated data symbols in the CCE, denoted as N symb . Each RG can consist of a part (ρ) of the time resource elements (TREs) in an OFDM symbol and span the frequency resource elements associated with a single DFT module. For a single DFT module, the total number of sub-carriers (e.g., frequency resources) allocated for the DFT can be equal to the DFT size (e.g., the number of samples in the frequency domain (i.e., after the DFT)), while the total number of time resources (TREs) associated with a single DFT can be equal to the number of samples in the time domain (i.e., before the DFT) multiplied by the ratio of the size of the IFFT module to the size of the DFT module. The total time-frequency resources allocated to the RG associated with the CCE will correspond to the CCE size and can be defined according to the number of TREs and FRGs, i.e., the CCE can be associated with frequency resource groups and time resource elements of resource groups, such that each RG is allocated (e.g., assuming equal DFT sizes and / or equal RG sizes) time-frequency resources. The smallest unit of time-frequency resources is 1 FRG and 1 TRE.

[0175] Considering a CCE size of 54 REs (e.g., 54 modulated symbols) and two DFT modules, i.e., where each DFT is associated with a frequency resource group of size , and N IFFT is the IFFT module size, the total number of time-frequency resources required for a single CCE can be determined according to Obtained (e.g., each modulated symbol requires 4 IFFT samples). Then, for the number of resource groups per CCE The number of time-frequency resources per RG is where each RG is allocated Each of these RGs is associated with a DFT module, and each RG can carry a number of REs or modulated symbols. Typically, the TREs allocated for a CCE can span one or more OFDM symbols or a part ρ of an OFDM symbol.

[0176] The size of the RG and the number of RGs associated with a CCE can depend on the DFT size (in the frequency domain / time domain / code domain) CCE multiplexing pattern, the number of frequency resource groups allocated for a CCE and the number of TREs allocated for a CCE any one of them. Depending on the DFT size and the CCE multiplexing pattern, the RGs belonging to a CCE can have different or the same size.

[0177] Figure 5I Examples of two different scenarios of the number of RGs per CCE based on the CCE multiplexing pattern are shown. In this example, the CCE size is 60 REs (e.g., modulated symbols), and the DFT size is 120 (e.g., ). In part a of FIG. I, since only two RGs / CCEs can be multiplexed in the time domain within each DFT operation (e.g., ), the number of TREs per RG / CCE per FRG (e.g., DFT module) is i.e., each RG / CCE is allocated half of the TREs per OFDM symbol per FRG. Note that half of the TREs in the TREs can carry 60 modulated symbols (i.e., thus resulting in ). Therefore, based on the pre-configured / signaled CCE size, only a single RG is required per CCE (i.e., ).

[0178] In Figure 5I part b, since four CCEs can be multiplexed in the time domain within each DFT operation (e.g., ), the number of TREs per RG / CCE per FRG (e.g., DFT module) is That is, each RG / CCE is allocated one quarter of the TREs in each FRG per OFDM symbol. Note that one quarter of the TREs in the TRE can carry only 30 modulated symbols (i.e., which results in ), and thus, based on the pre-configured / signaled CCE size, two RGs may be required per CCE (i.e., ). The two RGs of each CCE are allocated different frequency positions (e.g., FRGs) with different DFT precoding blocks, as Figure 5I shown.

[0179] The RGs of the CCE can be interleaved in the time domain or / and the frequency domain. Figure 5J Some examples of different RG to CCE interleaving scenarios in the time domain, the frequency domain, or both domains are shown. The first example (e.g., Figure 5J parts a and b) shows a 2-symbol CORESET with 4 CCEs multiplexed using 2 FRGs (i.e., DFTs), each FRG being 10 PRBs in size, and one OFDM symbol being allocated for the PDCCH, where each CCE can be allocated a size of 5 PRBs and can be divided into 2 RGs. Two interleaving cases can be shown in this example. The first case has frequency domain interleaving (e.g., Figure 5J part a), and the second case has time domain interleaving (e.g., Figure 5J part b). In the first case, each of the 4 CCEs can be distributed across two FRGs (i.e., across the frequency domain on two different DFTs, where the CORESET frequency allocation can be continuous or non-continuous) via the 2 RGs allocated to each CCE. In the second case, each pair of CCEs is dedicated to a single FRG (i.e., DFT module), and the corresponding RGs can be interleaved in time.

[0180] The second example (e.g., Figure 5J parts c and d) shows a 3-symbol CORESET with 8 CCEs multiplexed using 2 FRGs (i.e., DFTs), each FRG being 10 PRBs in size, and two OFDM symbols being allocated for the PDCCH, where each CCE can be allocated a size of 5 PRBs and can be divided into 2 RGs. Two interleaving cases can be shown in this example. The first case has time domain interleaving (e.g., Figure 5J part c), and the second case has a combination of time domain and frequency domain interleaving (e.g., Figure 5J part d). In the first case (e.g., Figure 5JFor part c), each of the 8 CCEs can be dedicated to a single FRG (e.g., 4 CCEs can be time-domain multiplexed within a single FRG), and 2 corresponding RGs can be assigned to different OFDM symbols. In the second case (e.g., Figure 5J For part d), 2 RGs corresponding to a single CCE can be assigned different FRGs and OFDM symbols (e.g., assigned to different DFT modules and at different times). For example, the first RG (e.g., RG 0) of the first CCE (e.g., CCE0) can be assigned to the first FRG (e.g., FRG 0) at the first OFDM symbol (i.e., assigned for PDCCH), while the second RG (e.g., RG 1) of the first CCE can be assigned to the second FRG (e.g., FRG 1) at the second OFDM symbol (i.e., assigned for PDCCH).

[0181] Due to the possible additional overhead on control channel detection at the WTRU (e.g., in terms of processing complexity and / or processing latency) due to the use of the DFT-s-OFDM waveform, the WTRU may have to report either its hardware capabilities and / or processing requirements (e.g., complexity, power consumption, latency, etc.). Then, the reported WTRU capabilities can include multiple parameters such as CORESET configuration, search space configuration, and other design aspects.

[0182] For example, during registration or as part of the WTRU capabilities indication, the WTRU can indicate to the base station / network its ability to monitor the PDCCH, which can include any of the following. The WTRU can indicate to the base station / network the maximum (e.g., supported) number of DFT modules (transform precoders) per symbol or / and per time slot or / and per serving cell. For example, the WTRU can indicate an integer that indicates the number N of supported FRGs (e.g., DFTs) that can be monitored by the WTRU FRG . The WTRU can indicate one or more DFT module sizes supported by the WTRU. For example, the WTRU can indicate an integer that indicates the maximum DFT / FRG size supported, e.g., in terms of subcarriers or resource blocks (e.g., ). For a given set of parameters and one or more DFT sizes supported by the WTRU, the WTRU can indicate the maximum number of PDCCH candidates per symbol or / and per time slot or / and per serving cell that can be decoded by the WTRU, e.g., indicating the maximum number of PDCCH candidates that can be supported in a time slot as one or more integers that are associated with one or more DFT module sizes at the specified set of parameters.

[0183] The WTRU may indicate the maximum number of PDCCH candidates per symbol or / and per time slot or / and per serving cell that can be decoded by one or more numbers of DFT modules supported by the WTRU per symbol / slot. For one or more DFT sizes supported by the WTRU, the WTRU may indicate the maximum number of non-overlapping CCEs per symbol or / and per time slot or / and per serving cell in the time domain, frequency domain, and / or both domains. For one or more numbers of DFT modules supported by the WTRU per symbol / slot, the WTRU may indicate the maximum number of non-overlapping CCEs per symbol and / or per time slot and / or per serving cell in the time domain, frequency domain, and / or both domains. The WTRU may indicate one or more of the (e.g., per symbol / slot or across multiple symbols / slots supported) PDCCH monitoring spans / groups combinations (X,Y) supported by the WTRU for one or more DFT sizes or / and numbers of DFT modules, where X is the minimum separation (e.g., in terms of the number of symbols) between the first symbols of two consecutive spans of a PDCCH monitoring occasion (including across time slots), and Y is the number of symbols of the span. In some examples, the span may start at the first symbol at which the PDCCH monitoring occasion starts and end at the last symbol at which the PDCCH monitoring occasion ends, where the number of symbols of the span is up to. Then, the network may limit the number of PDCCH candidates to be monitored (e.g., blindly detected) and / or configure based on the received WTRU capabilities.

[0184] For example, the WTRU may receive a CORESET configuration as part of ControlResourceSetZero and / or ControlResourceSet from a base station using higher layer signaling (e.g., RRC or system information). The CORESET configuration may include any one or more of a CORESET index, a time domain configuration, a frequency domain configuration, a configuration of DMRS for the PDCCH, a CCE structure, a pre-coder granularity, and / or an indication of the CCE aggregation level and the number of PDCCH candidates for each indicated aggregation level.

[0185] The CORESET configuration may include a time-domain configuration, which may indicate any short format or long format of the pattern of OFDM symbols for allocation. The CORESET configuration may indicate the number of allocated OFDM symbols that may be indicated explicitly or implicitly. The CORESET configuration may include an indication of, for example, short format 1, which may be used to indicate that 2 OFDM symbols are allocated to the PDCCH and the DMRS for the PDCCH, while an indication of, for example, short format 2 may be used to indicate that 3 OFDM symbols are allocated to the PDCCH and the DMRS for the PDCCH, and so on. An indication of, for example, long format 1 may be used to indicate that 4 OFDM symbols are allocated to the PDCCH and the DMRS for the PDCCH, while an indication of, for example, long format 2 may be used to indicate that 5 OFDM symbols are allocated to the PDCCH and the DMRS for the PDCCH, and so on. The CORESET configuration may also indicate the index of the OFDM symbol within the time slot that may be dedicated to the PDCCH and the DMRS for the PDCCH. The OFDM symbol index may be used to indicate the starting symbol of the CORESET within the time slot.

[0186] The CORESET configuration may indicate a frequency-domain configuration. For example, the CORESET configuration may indicate an RB offset from, for example, the first resource block (RB) allocated to the CORESET to the first RB of the bandwidth part (BWP). The CORESET configuration may include the frequency-domain resources allocated for the CORESET, which may correspond to contiguous or non-contiguous resource allocation (e.g., the resources may be indicated according to RBs, RB groups, or FRGs).

[0187] The CORESET configuration may indicate the configuration of DMRS for PDCCH. For example, the CORESET configuration may include an indication of an additional DMRS configuration, the mapping / position of the PFDM symbols assigned to the DMRS for PDCCH, an indication of the frequency resources, an indication of the DMRS sequence parameters, and / or an indication of the DMSR modulation type, spreading factor, and / or orthogonal sequence index. The mapping / position of the OFDM symbols assigned to the DMRS for PDCCH may be indicated explicitly and / or implicitly. The OFDM symbol position may be explicitly indicated as a set of indices relative to, for example, the first OFDM in the slot containing the CORESET or the first OFDM symbol in the CORESET. Alternatively, the position of the OFDM symbol may be explicitly indicated as the index of the OFDM symbol and the number of consecutive OFDM symbols assigned to the DMRS for PDCCH. The position of the OFDM symbol may be implicitly indicated based on a set of preconfigured patterns, which may depend on, for example, the time domain configuration of the CORESET and the additional DMRS indication. When a subset of REs or / and RBs within the bandwidth of the CORESET can be configured for DMRS, the frequency resources (e.g., RE / RB) considered for transmission of DMRS within any of the dedicated OFDM symbols in the dedicated OFDM symbols may be indicated. The frequency domain configuration of the resources selected for transmitting DMRS (e.g., associated with the CORESET) may be implicitly indicated based on a set of preconfigured patterns, which may depend on, for example, the RE index (within the RB), the RB index within the BWP selected for transmitting DMRS (e.g., associated with the CORESET). The indication of the DMRS sequence parameters may include, for example, sequence type, initialization seed, cyclic shift, base sequence, etc.

[0188] The CORESET configuration may indicate the CCE structure, interleaving, and / or multiplexing configuration. The CORESET configuration may indicate the CCE size, for example, according to the number of modulated symbols or the equivalent number of RE / RBs. The CCE size may be fixed (e.g., pre-configured at the network / WTRU) or configurable. The configurable CCE size may be explicitly signaled as part of the CORESET configuration or derived / determined based on other CORESET parameters (e.g., frequency domain and multiplexing configuration). The number of RGs per CCE may be indicated together with the corresponding RG size. The RG size per CCE may be explicitly signaled / indicated to the WTRU or derived / determined based on other CORESET configuration parameters (e.g., CCE size, number of RGs per CCE, multiplexing configuration, etc.). The number of FRGs (e.g., the number of DFTs per CORESET) and the size of each FRG may be indicated according to the number of subcarriers. In addition, an indication of interleaving, the interleaving size in the time domain and / or frequency domain, cyclic shift, and RG / CCE ordering indication, e.g., RGs / CCEs that are interleaved first in time and then in frequency, or RGs / CCEs that are interleaved first in frequency and then in time. An indication of either the time domain multiplexing option or the code domain multiplexing option may be indicated for each FRG and OFDM symbol. The CORESET configuration may also indicate the number of multiplexed RGs / CCEs per FRG, where the multiplexing may be performed over one or more OFDM symbols. When code domain multiplexing is indicated, an indication of the orthogonal (e.g., covering) code and the corresponding length, e.g., spreading factor, may be indicated.

[0189] The CORESET configuration may indicate the precoder granularity. The precoder granularity may be configured as sameAsFRG or allContiguousRBs. The precoder granularity may be configured as sameAsFRG when the same precoding weights can be applied to all RBs associated with an FRG (e.g., different precoding weights may be applied to RBs belonging to different FRGs). The precoder granularity may be configured as allContiguousRBs when the same precoding weights can be applied to all RBs belonging to contiguous RBs.

[0190] For example, a WTRU may use higher layer signaling (e.g., RRC or system information) to receive a search space configuration from a base station as part of SearchSpaceZero and / or SearchSpace. The search space configuration may include any one or more parameters. One parameter may be a CORESET index that indicates the associated CORESET. A PDCCH monitoring period and offset (expressed as an integer number of slots) may be provided. A PDCCH monitoring pattern within a slot may be provided that indicates one or more first symbols of the CORESET within one or more slots for PDCCH monitoring. In addition, a duration may be provided that indicates the number of (e.g., consecutive) slots for which the search space exists. An indication may be provided for the CCE aggregation level and the number of PDCCH candidates for each indicated aggregation level. Other options include a search space type parameter that may be set to common or WTRU-specific depending on the category of the search space and an indication of the DCI format that may use the search space being configured to carry. A frequency monitoring location may be provided to define the association of the search space with multiple monitoring locations in the frequency domain and to indicate whether the pattern configured in the associated CORESET may be replicated to a specific RB or FRG set. Each bit in the bitmap corresponds to an RB or FRG set, and the leftmost (most significant) bit corresponds to RB / FRG set 0 in the BWP. A bit set to 1 indicates that the frequency domain resource allocation replicated from the pattern configured in the associated CORESET may be mapped to the RB / FRG set.

[0191] For a given time-frequency allocation / configuration of a CORESET, other design considerations may be derived / used, including different CCE structures, interleaving, and multiplexing configurations (i.e., depending on the number of FRGs / DFTs, FRG / DFT size, number of CCEs multiplexed in the time domain / code domain per FRG / DFT within an OFDM symbol, RG interleaving pattern, etc.). The CCE structure, interleaving, and / or multiplexing configuration may be derived based on any one of the following criteria / factors. These criteria / factors may include any combination of network (e.g., BS) energy efficiency, CCE aggregation, frequency domain diversity, time domain diversity, pre-coding, WTRU complexity / capability, and / or control channel congestion.

[0192] For network energy efficiency, for a given bandwidth allocation (e.g., contiguous or non - contiguous PRBs), the PAPR can be inversely proportional to the DFT size and directly proportional to the number of DFT precoders. Compared with a smaller number of DFT precoders (e.g., with a larger DFT size, higher BS energy efficiency), a configuration with a higher number of DFT precoders (e.g., with a smaller DFT size) applied to the allocated PRBs in an OFDM symbol can have a higher PAPR (e.g., lower BS energy efficiency). A lower PAPR can be beneficial for improving the coverage of the network.

[0193] CCE aggregation can be defined, where a WTRU can be allocated multiple CCEs (e.g., CCE aggregation level > 1) to improve coverage. Aggregation can be performed in the time domain (e.g., within an OFDM symbol or / and over multiple OFDM symbols), e.g., in a noise - limited scenario (or a relatively fast - fading channel scenario); or aggregation can be performed in the frequency domain (e.g., within an OFDM symbol or / and over multiple OFDM symbols), e.g., in the case of frequency - selective fading occurring over the allocated bandwidth of the CORESET.

[0194] Frequency - domain diversity can be useful in the case of frequency - selective fading. The CCEs allocated to a WTRU or the RGs associated with the WTRU's CCEs can be interleaved within an OFDM symbol or / and over multiple OFDM symbols in the frequency domain to achieve frequency diversity. The CCEs allocated to a WTRU or the RGs associated with the WTRU's CCEs can be interleaved and / or aggregated in the frequency domain using distributed (e.g., different / separate) DFT precoders or clustered DFT precoders.

[0195] Time - domain diversity can be useful in the case of a fast - fading channel (e.g., a channel coherence time on the order of the OFDM symbol length). The CCEs allocated to a WTRU or the RGs associated with the WTRU's CCEs can be interleaved and / or aggregated within an OFDM symbol and / or over multiple OFDM symbols in the time domain to achieve time diversity.

[0196] From the perspective of (e.g., transmitter) precoding, there may be limitations. It may be necessary to apply the same precoding to all data within an OFDM symbol mapped using a DFT precoder. After DFT precoding within an OFDM symbol, it may be necessary to apply the same precoding weights to all CCEs / RGs multiplexed in the time / coding domain. These CCEs / RGs can belong to one or more WTRUs.

[0197] The WTRU may have different complexities / capabilities in terms of the number of supported DFT pre - decoders and the corresponding DFT sizes per serving cell per OFDM symbol / slot. Blind decoding generates a significant processing load at the WTRU. Performing DFT decoding at the WTRU side to extract the WTRU's PDCCH may result in additional WTRU processing time / overhead. The maximum number of PDCCH candidates per serving cell per time slot of the PDCCH with DFT pre - coding and / or the maximum number of CCEs that require channel estimation (e.g., according to the sub - carrier spacing) may be defined.

[0198] The control channel congestion parameter can be generated by a moderate CCE aggregation level (and / or higher - granularity pre - coding) with frequency diversity (e.g., using distributed or clustered DFT pre - coding within an OFDM symbol and / or over multiple OFDM symbols), and this frequency diversity can be selected at the cost of lower network (e.g., gNB) energy efficiency (e.g., due to higher PAPR) to reduce the control channel blocking probability. A higher aggregation level (and / or lower - granularity pre - coding) with time - domain multiplexing via larger DFT pre - coding (e.g., assuming this configuration has lower frequency diversity compared to a previous configuration and / or lower CCE decoding performance due to squeezing the CCE - modulated symbols over a shorter time period) can be used to achieve higher network energy efficiency (e.g., lower PAPR) at the cost of a higher blocking probability.

[0199] Figure 5K An illustrative example of a 2 - symbol CORESET with 24 PRBs is shown, with both continuous and non - continuous PRB allocations. In the case of non - continuous allocation, a single DFT (clustered DFT[8]) or separate DFT pre - decoders can be applied. Among these three different scenarios, scenario (a) will have the lowest PAPR. In scenarios (b) and (c), scenario (b) will have better PAPR performance.

[0200] Figure 5L An illustrative example of a CORESET configuration with non - continuous PRB allocation with different RG interleaving scenarios is shown. Figure 5L Part (a) shows a 2 - symbol CORESET without RG interleaving, Figure 5L Part (b) shows a 2 - symbol CORESET with frequency - domain RG interleaving to achieve better frequency diversity, and Figure 5L Part (c) shows a 4 - symbol CORESET with time - domain interleaving across different OFDM symbols to achieve better time diversity.

[0201] The WTRU process related to determining DL control channel configuration may be defined as receiving a PDCCH containing downlink control information. For each DL BWP configured for the WTRU in a serving cell, the WTRU may determine a time domain configuration according to configuration parameters, which indicates the starting symbol index, time slot index, or / and frame index to be monitored for receiving the PDCCH. The configuration parameters include any one of the PDCCH monitoring period and offset, PDCCH monitoring mode, and duration provided in the associated search space configuration, as discussed herein in the section related to "WTRU capabilities, CORESET configuration, search space configuration, and design".

[0202] Given a frame, time slot, and starting symbol, the WTRU may determine a time domain configuration according to the time domain configuration provided in the associated CORESET, which indicates the number of (e.g., consecutive) OFDM symbols containing the PDCCH and DMRS. For a given time domain span (e.g., consecutive OFDM symbols) associated with the CORESET, the WTRU may determine the time domain pattern / mapping of (e.g., DCI) data and DMRS symbols according to configuration parameters, which include the position of the OFDM symbols assigned to the DMRS or any one of the pattern indices selected from a set of pre-configured patterns provided in the associated CORESET configuration, indication of additional DMRS configuration.

[0203] For each DL BWP configured for the WTRU in a serving cell, the WTRU may determine a frequency domain configuration according to the frequency domain configuration provided in the associated CORESET or / and the frequency monitoring position provided in the associated search space, which indicates a set of (e.g., consecutive or / and non-consecutive) RBs to be monitored for receiving the PDCCH (i.e., associated with the OFDM symbols assigned for transmitting DCI data).

[0204] The WTRU can determine the frequency-domain configuration based on an explicit indication of the frequency resources allocated for the DMRS or a pattern index selected from a set of pre-configured patterns provided in the associated CORESET configuration. The frequency-domain configuration indicates the set of RBs allocated on the OFDM symbols containing the DMRS and to be monitored for proper decoding of the PDCCH for channel estimation purposes, and the set of REs within each indicated RB. For channel estimation purposes, the WTRU can determine the DMRS sequence based on a configuration parameter, which includes any one of the sequence type, initialization seed, cyclic shift, and base sequence provided in the associated CORESET configuration. For channel estimation purposes, the WTRU can determine the frequency selectivity of the precoding applied by the network based on the precoding granularity provided in the associated CORESET configuration.

[0205] The WTRU can determine the CCE allocation pattern indicating the association / mapping between the CCE index and the time-frequency resources (e.g., OFDM symbols, FRG) of a given CORESET containing DCI data based on a configuration parameter, which indicates the CCE structure, interleaving, and multiplexing configuration provided in the CORESET configuration.

[0206] The WTRU can be provided with a configuration parameter as part of the CORESET configuration, which includes an indication of code-domain multiplexing, OFDM symbol-level time-domain multiplexing, spreading factor (or orthogonal cover code length, L occ ), orthogonal cover code (e.g., extended sequence), CCE size, number of FRGs (e.g., DFT), and the associated FRG / DFT size at least one of an indication of time-domain interleaving and the associated interleaving size, and an indication of frequency-domain interleaving and the associated interleaving size. With this configuration setting, the WTRU can perform the following steps.

[0207] In a first step, the WTRU can determine the RG size (N Symb ) associated with each FRG / DFT, in which case each RG will be allocated the entire OFDM symbol, where L occ number of RGs use different orthogonal cover codes for multiplexing in the code domain. The number of modulated symbols associated with each RG can be reduced according to a factor L occ corresponding to the spreading factor. In a second step, the WTRU can determine the number of RGs per CCE In a third step, the WTRU can determine the CDM RG set size, i.e., the number of RGs multiplexed in the code domain per OFDM symbol per FRG, which is equal to L occ。For each FRG and OFDM symbol, an associated OCC can be assigned an index. For example, in the case of 4 OCCs (L occ = 4), the indices OCC 0, OCC 1, OCC 2, and OCC 3 are assigned to the 4 OCCs. In a fourth step, the WTRU can determine an RG interleaving / assignment pattern within an OFDM symbol, across OFDM symbols and FRGs, using different OCCs based on the OCC length, time domain interleaving size, and frequency domain interleaving size.

[0208] For code domain multiplexing that indicates only the interleaver size M (≥1) for time domain interleaving and not for frequency domain interleaving or indicates the interleaver size N (=1) for frequency domain interleaving, the RG associated with the CCE can be mapped to the time domain, frequency domain, and code domain by first moving in the time domain, second moving in the frequency domain (e.g., when the number of FRGs > 1), and then moving in the code domain. For each DFT module, the total number of OFDM symbols (dedicated to DCI data transmission) can be divided into M parts. Starting from the lowest CCE index (e.g., CCE 0), the RG associated with the CCE (starting from the first RG of the CCE) can be first mapped to the OFDM symbols in the time domain by rotating around the M parts in increasing order of the OFDM symbol indices within the first FRG using the first OCC, and then moved up in the frequency domain in the same manner to be mapped to the OFDM symbols associated with the second FRG, and so on. Once all OFDM symbols and FRGs can be assigned using the first OCC, the remaining RGs can be mapped in the same manner, starting from the first OFDM symbol, first FRG, in increasing order of the CCE index, but using the second OCC, and so on.

[0209] Figure 5MAn example of an RG mapping with time domain interleaving and code domain multiplexing configuration is shown for a 5-symbol CORESET with CCE size = 120, OCC length = 2, number of DFTs with the same DFT size 60 = 2, M = 2, and N = 1. One symbol (the second symbol) is allocated for DMRS. Given the number of OFDM symbols, number of DFTs, DFT size, CCE size, OCC length (e.g., number of OCCs), the WTRU can determine that 4 CCEs can be multiplexed within a given CORESET. In this example, since there may be 4 OFDM symbols dedicated to DCI data transmission and the value of M = 2, two parts can be considered in the time domain, where the first part consists of the first OFDM symbol and the third OFDM symbol, and the second part consists of the fourth OFDM symbol and the fifth OFDM symbol. The mapping of the RG can be performed by first using the first OCC and then rotating over the two parts to utilize the OFDM symbols of the first FRG. After utilizing the first FRG, the OFDM symbols associated with the second FRG can be utilized in the same manner as continuing to use the first OCC. Once all the OFDM symbols of the second FRG are available, the mapping can be continued by first shifting back the OFDM symbols of the first FRG, then shifting back the OFDM symbols of the second FRG but utilizing the second OCC.

[0210] For code domain multiplexing that indicates only interleaving in the frequency domain for the interleaver size N (≥1) and does not indicate interleaving in the time domain or indicates interleaving in the time domain for the interleaver size M (=1), the RG associated with the CCE can be mapped to the time domain, frequency domain, and code domain by first moving in the frequency domain, second moving in the time domain (e.g., when the number of OFDM symbols dedicated to DCI transmission > 1), and then moving in the code domain. For each OFDM symbol, the total number of FRGs can be divided into N parts. Starting from the lowest CCE index (e.g., CCE 0), the RG associated with the CCE (starting from the first RG of the CCE) can be first mapped in the frequency domain by rotating around the N parts in increasing order of FRG index on the first OFDM symbol using the first OCC, and then shifted to the right in the time domain in the same manner to be mapped to the second OFDM symbol, and so on. Once the first OCC can be used to allocate all the FRGs and OFDM symbols, the remaining RGs can be mapped in the same manner, starting from the first OFDM symbol, first FRG, in increasing order of RG and CCE index, but using the second OCC, and so on.

[0211] Figure 5NAn example of RG mapping with frequency domain interleaving and code domain multiplexing configuration is shown, which is used for a 3-symbol CORESET with CCE size = 120, OCC length = 2, number of DFTs with the same DFT size 60 = 4, N = 2, and M = 1. One symbol (the second symbol) is allocated for DMRS. Given the number of OFDM symbols, number of DFTs, DFT size, CCE size, OCC length, the WTRU can determine that 4 CCEs can be multiplexed. In this example, since there may be 4 FRGs and the value of N = 2, two parts can be considered in the frequency domain, where the first part consists of the first FRG and the second FRG, and the second part consists of the third FRG and the fourth FRG. The mapping of the RG can be performed by first using the first OCC and then rotating on the two parts to utilize the FRG of the first OFDM symbol. After utilizing the first OFDM symbol, the FRG associated with the second OFDM symbol can be utilized in the same way as continuing to use the first OCC. Once all the FRGs of the second OFDM symbol can be used, the mapping can be continued by first moving back the FRG of the first OFDM symbol and then moving back the second OFDM symbol but utilizing the second OCC.

[0212] For code domain multiplexing that indicates the interleaver size M (≥1) by interleaving in both the time domain and the frequency domain and indicates the interleaver size N (≥1) by interleaving in the frequency domain, the RG associated with the CCE can be mapped to the time-frequency resources by moving in both the time domain (e.g., when the number of OFDM symbols dedicated to DCI transmission > 1) and the frequency domain (e.g., when the number of FRGs > 1) and utilizing the OCC configured in the code domain. For each FRG, the total number of OFDM symbols (e.g., dedicated to DCI data transmission) can be divided into M parts. For each OFDM symbol, the total number of FRGs can be divided into N parts. Starting from the lowest CCE index (e.g., CCE 0), the RG associated with the CCE (starting from the first RG of the CCE) can be mapped by rotating around the M parts in the increasing order of the OFDM symbol index and rotating around the N parts in the increasing order of the FRG index, while using the OCCs arranged in the increasing order of the OCC index.

[0213] Figure 5OAn example of an RG mapping with time-domain and frequency-domain interleaving configurations with code-domain multiplexing is shown, where CCE size = 120, OCC length = 2, number of DFTs with the same DFT size 60 = 4, M = 2 and N = 2. Given the number of OFDM symbols, number of DFTs, DFT size, CCE size, OCC length, the WTRU can determine that 8 CCEs can be multiplexed within a given CORESET. In this example, since there may be 4 OFDM symbols dedicated to DCI data and there may be 4 FRGs, where the values of M and N are equal to 2, the mapping of the RG can be rotated simultaneously on 2 parts of the OFDM symbols (the first part consists of the first OFDM symbol and the third OFDM symbol, and the second part consists of the fourth OFDM symbol and the fifth OFDM symbol) and 2 parts of the FRGs (the first part consists of the first FRG and the second FRG, and the second part consists of the third FRG and the fourth FRG) by first using the first OCC and then the second OCC, and so on. Starting from the lowest index, the RG of each CCE can first use the mapping to the next available OFDM symbol (with the lowest FRG), and then move to the next OFDM symbol and FRG after rotation, where M = N = 2. The first OCC can be used first to perform the mapping of the RG on all OFDM symbols and FRGs. Once all OFDM symbols and FRGs are available, the second OCC can be used in the same way to map the remaining RGs (e.g., starting from the lowest OFDM symbol and FRG).

[0214] In a fifth step, the WTRU can determine, for example, according to equation (D) herein, the CCE indices for aggregation level L indicated in the search space corresponding to each PDCCH candidate.

[0215] Then, the WTRU can receive the PDCCH and decode the DCI via the PDCCH candidate based on the received and determined configurations. Receiving the PDCCH can also include performing an IDFT on the FRG and OFDM symbol associated with the PDCCH candidate based on the determined CCE indices, the number of RGs per CCE, and the CDM RG set allocation pattern. This can also include extracting and despreading the RGs corresponding to the PDCCH candidate based on the determined correspondence between the RGs and the OCC per CDM RG set. Additionally, this can include demodulating the symbols received via all the RGs associated with the PDCCH candidate, detecting the DCI format, and decoding the DCI.

[0216] The WTRU can be provided with configuration parameters as part of the CORESET configuration, the configuration parameters including an indication of code-domain multiplexing, CCE size, number of RGs per CCE Orthogonal covering codes (e.g., spreading sequences), the number of FRGs (e.g., DFTs), and the associated FRG / DFT sizes At least one of an indication of time domain interleaving and an associated interleaving size, and an indication of frequency domain interleaving and an associated interleaving size. With this configuration setting, the WTRU can perform the following steps:

[0217] In a first step, the WTRU can determine the RG size (N Symb ) associated with each FRG / DFT, In a second step, the WTRU can determine the OCC length (number of OCCs) for code domain multiplexing per OFDM symbol per FRG, In additional steps (e.g., third to sixth steps), the WTRU can be the same as that given in the previous implementation of code domain multiplexing.

[0218] The WTRU can be provided with configuration parameters as part of the CORESET configuration, and the configuration parameters include an indication of code domain multiplexing, a spreading factor (or orthogonal covering code length, L occ ), the number of RGs per CCE Orthogonal covering codes (e.g., spreading sequences), the number of FRGs (e.g., DFTs), and the associated FRG / DFT sizes At least one of an indication of time domain interleaving and an associated interleaving size, and an indication of frequency domain interleaving and an associated interleaving size. With this configuration setting, the WTRU can perform any combination of the following steps. In a first step, the WTRU can determine the RG size (N Symb ) associated with each FRG / DFT, In a second step, the WTRU can determine the CCE size, In additional steps (e.g., third to sixth steps), the WTRU can be the same as that given in the previous implementation of code domain multiplexing.

[0219] The WTRU can be provided with configuration parameters as part of the CORESET configuration, and the configuration parameters include an indication of code domain multiplexing, code domain multiplexing with TRE block-level time domain multiplexing, a spreading factor (or orthogonal covering code length, L occ ), the CCE size, the number of RGs per CCE Orthogonal covering codes (e.g., spreading sequences), the number of FRGs (e.g., DFTs), and the associated FRG / DFT sizes At least one of an indication of time domain interleaving and an associated interleaving size and / or an indication of frequency domain interleaving and an associated interleaving size. With this configuration setting, the WTRU can perform any combination of the following steps.

[0220] In a first step, the WTRU may determine the RG size (N Symb ) associated with each FRG / DFT In a second step, the WTRU may determine the CDM RG set size, i.e., the number of RGs multiplexed in the code domain per OFDM symbol per FRG, which is equal to L occ . In a third step, the WTRU may determine the number of CDM RG sets multiplexed in the time domain for each FRG In this case, each CDM RG set may be allocated a portion of the symbols in the time domain, where L occ RGs are multiplexed in the code domain using different orthogonal cover codes

[0221] In a fourth step, the WTRU may determine the number of TREs per TRE block (i.e., associated with each CDM RG set) as L OCC ×N Symb multiplied by the ratio between the size of the IFFT module and the size of the DFT module, where the IFFT module size may be preconfigured or signaled via higher layer signaling (e.g., RRC) or SI. In a fifth step, the WTRU may determine the number of TRE blocks within each FRG as the product of the determined and the number of OFDM symbols allocated for DCI. For each FRG, each TRE block may be assigned an index according to the process described earlier in this section. In a sixth step, the WTRU may determine the RG interleaving / assignment pattern within the OFDM symbol, across OFDM symbols and FRGs, using different OCCs according to the OCC length, time domain interleaving size, and frequency domain interleaving size

[0222] For code domain multiplexing that indicates the interleaver size M (≥1) only in the time domain and does not indicate interleaving in the frequency domain or indicates the interleaver size N (=1) for interleaving in the frequency domain, the RG associated with the CCE can be mapped to the time domain, frequency domain, and code domain by first moving in the time domain, then moving in the frequency domain (e.g., when the number of FRGs > 1), and then moving in the code domain. For each DFT module, the total number of TRE blocks available on the OFDM symbol containing the DCI data can be divided into M parts. Starting from the lowest CCE index (e.g., CCE 0), the RG associated with the CCE (starting from the first RG of the CCE) can be mapped to the TRE blocks first in the time domain by rotating around the M parts in ascending order of the TRE block indices within the first FRG using the first OCC, and then moving upward in the frequency domain in the same way to map to the TRE blocks associated with the second FRG, and so on. Once all the OFDM symbols and FRGs can be allocated using the first OCC, the remaining RGs can be mapped in the same way in ascending order of the CCE index, starting from the first OFDM symbol and the first FRG, but using the second OCC, and so on.

[0223] For code domain multiplexing that indicates the interleaver size N (≥1) only in the frequency domain and does not indicate interleaving in the time domain or indicates the interleaver size M (=1) for interleaving in the time domain, the RG associated with the CCE can be mapped to the time domain, frequency domain, and code domain by first moving in the frequency domain, then moving in the time domain (e.g., when the number of TRE blocks > 1), and then moving in the code domain. For each TRE block, the total number of FRGs can be divided into N parts. Starting from the lowest CCE index (e.g., CCE 0), the RG associated with the CCE (starting from the first RG of the CCE) can be mapped first in the frequency domain by rotating around the N parts in ascending order of the FRG indices on the first TRE block using the first OCC, and then moving to the right in the time domain in the same way to map to the TRE of the second TRE block of the FRG, and so on. Once all the FRGs and OFDM symbols can be allocated using the first OCC, the remaining RGs can be mapped in the same way in ascending order of the RG and CCE indices, starting from the first TRE block and the first FRG, but using the second OCC, and so on.

[0224] For code domain multiplexing that interleaves the indication of interleaver size M (≥1) in both the time domain and the frequency domain and interleaves the indication of interleaver size N (≥1) in the frequency domain, the RG associated with the CCE can be mapped to time-frequency resources by moving in both the time domain (e.g., when the number of TRE blocks > 1) and the frequency domain (e.g., when the number of FRGs > 1) and by using the OCC configured in the code domain. For each FRG, the total number of TRE blocks available on the OFDM symbols dedicated to DCI data can be divided into M parts. For each TRE block, the total number of FRGs can be divided into N parts. Starting from the lowest CCE index (e.g., CCE 0), the RG associated with the CCE (starting from the first RG of the CCE) can be mapped in such a way that it rotates around the M parts in increasing order of TRE block index and rotates around the N parts in increasing order of FRG index, while using the OCC arranged in increasing order of OCC index.

[0225] In the seventh step, the WTRU can determine, for example, according to equation (D) here, the CCE index for aggregation level L indicated in the search space corresponding to each PDCCH candidate.

[0226] The WTRU process related to determining and updating the DL control channel configuration can consider the adaptation of the configuration based on any one of the WTRU complexity / capability (e.g., including power saving requirements), network energy efficiency, channel characteristics, and / or control channel congestion. The WTRU can receive the configuration of the search space and / or CORESET to monitor the PDCCH. The WTRU can determine, for example, the power consumption overhead caused by the need to utilize multiple IDFT modules based on the received configuration, which may be intolerable within a specific time period.

[0227] The WTRU may be seeking coverage extension, or the channel characteristics may be significantly changed due to blockage or orientation change, etc. The network can, for example, trade off its energy efficiency by reducing the CCE aggregation level to accommodate more control channels but using multiple smaller DFTs to achieve a higher pre-coding granularity, thereby reducing control channel congestion. The DL control channel configuration adaptation can be based on either the measurement report from the WTRU or the indication of the preferred configuration (e.g., from a list of signaled and / or predefined configurations).

[0228] The WTRU may use a first configuration of a search space and / or a CORESET received, for example, in either an RRC and system information message to monitor the PDCCH and receive DCI. The WTRU may perform channel measurements including any one of received signal strength, coherence bandwidth, coherence time, delay spread, and Doppler spread. The WTRU may determine either a first condition regarding the measurement and a second condition regarding power consumption. The WTRU may send an indication of a preferred second configuration of the search space and / or CORESET. The WTRU may receive a third configuration of the search space and / or CORESET to monitor the PDCCH and receive DCI.

[0229] The first configuration of the search space and / or CORESET may be a default configuration independent of either the capabilities of the WTRU and existing and / or previous channel conditions. For example, the first configuration may be determined based on the received pdcch-ConfigSIB1 in the MIB (e.g., determining the common search space and CORESET #0) or the PDCCH-ConfigCommon received in BWP-DownlinkCommon in SIB1. In a second implementation, the first configuration of the search space and / or CORESET may be received in response to the WTRU reporting its capabilities. For example, the first configuration may be determined based on the PDCCH-Config received in BWP-DownlinkDedicated in either an RRCSetup, RRCResume, or RRCReconfiguration (e.g., configured WTRU-specific PDCCH parameters such as controlResourceSet).

[0230] WTRU capability information may include any one or more of the parameters described herein. These parameters may be explicitly indicated to the network or as an index to a set / tuple of known values at both the WTRU and the network. One or more parameters may also be indicated to the network as a set of one or more indexes, each index corresponding to a set / tuple of known values. For example, the WTRU may explicitly report a set of tuples to the network in the following format, e.g., {(1,120,10),(2,60,10),…}. Alternatively, the WTRU may report a set of indexes, e.g., {s 1 ,s 2 ,…}, where the first index s 1 may be used to indicate a first tuple of values, e.g., and the second index s 2 may be used to indicate a second tuple of values, e.g., And so on, and the mapping between the index values and the tuples is known a priori at both the WTRU and the network.

[0231] The first configuration of the search space and / or CORESET may depend on one or more parameters indicating the channel state between the WTRU and the network, and the one or more parameters may be signaled by the WTRU to the network in one or more previous measurement reports. The channel state parameters may include / explicitly or implicitly indicate any one of received signal strength measurement, coherence bandwidth, coherence time, delay spread, and Doppler spread.

[0232] The first configuration further includes a configuration of measurements to be performed by the WTRU for evaluating the search space and / or CORESET configuration adaptation conditions. Alternatively, the measurement configuration may be received in a separate RRC message (e.g., RRCReconfiguration or RRCResume message). When the WTRU is in the RRC idle / inactive state, the measurement configuration may be provided as part of the system information, e.g., as part of SIB2 or SIB11. The measurement configuration may also include one or more indications of any of the evaluation conditions and corresponding thresholds (e.g., adaptation indication criteria). Alternatively, the evaluation conditions and / or corresponding thresholds (e.g., adaptation indication criteria) may be preconfigured (e.g., known a priori) at the WTRU.

[0233] The WTRU may receive an indication of activation / deactivation (e.g., enable / disable) of the search space and / or CORESET configuration adaptation in either an L1 message (e.g., DCI) or an RRC message (e.g., RRCReconfiguration message). For example, the WTRU may receive a DCI indicating deactivation (e.g., disable) of the search space and / or CORESET adaptation. For example, the WTRU may receive an RRCReconfiguration message indicating activation of the search space and / or CORESET adaptation. The RRCReconfiguartion message may also include an update of the measurement configuration and / or adaptation indication criteria.

[0234] The first condition regarding measurement evaluates the measurement of the received signal strength relative to either a first threshold or a second threshold. In one example, the WTRU determines a received signal strength below the first threshold and sends an indication of a second configuration that enables precoding with a finer granularity. The WTRU determines a received signal strength above the second threshold and sends an indication of a second configuration that enables precoding with a coarser granularity. In an alternative, the first condition regarding measurement evaluates the measurement of the channel coherence bandwidth (e.g., or delay spread) relative to a third threshold. In one example, the WTRU determines a coherence bandwidth above the third threshold and sends an indication of a second configuration of a long CORESET format, e.g., to support higher mobility.

[0235] Based on the determined high coherence bandwidth, the WTRU may not benefit from the frequency diversity provided by DFT spreading and may thus decide to select a different CORESET format (e.g., long format) with more time resources than frequency, such that the WTRU can benefit from time-domain diversity (e.g., due to shorter coherence time), especially at high mobility. The first condition regarding measurement (e.g., jointly) evaluates the measurement of the received signal strength and the measurement of the channel coherence bandwidth (e.g., or delay spread). In one example, sending an indication of the second configuration of the long CORESET format may depend on determining a received signal strength below the first threshold and a coherence bandwidth above the third threshold. For all alternatives, any one or more of the thresholds may be preconfigured at the WTRU or signaled in any one of the L1, MAC-CE, RRC, and system information messages.

[0236] One or more of the alternatives of the first condition may be considered together with a second condition regarding the power state of the WTRU (e.g., power consumption and / or battery state and / or power saving preference). The second condition evaluates the power state of the WTRU relative to one or more thresholds. In one example, the WTRU determines a total power consumption above the first threshold and sends an indication of a second configuration of a smaller CORESET size (e.g., according to the number of allocated frequency resources), a smaller number of DFTs, and / or a smaller number of PDCCH candidates. This condition evaluates the battery state relative to a second threshold. In an alternative, the second condition may be considered independently of the first condition and may be used to activate / deactivate the DFT-s-OFDM-based PDCCH, e.g., revert to the OFDM-based design of the PDCCH. For all alternatives, any one or more of the thresholds may be preconfigured at the WTRU or signaled in any one of the L1, MAC-CE, RRC, and system information messages.

[0237] The indication of the preferred second configuration includes explicit signaling of one or more updated parameters of the first configuration. In an alternative, the indication can be an index to a configuration from one or more configurations that are a priori known (e.g., pre-configured) at both the WTRU and the network. The indication can be an index to a configuration from one or more configurations that are signaled from the network to the WTRU in either an RRC or a system information message. For all alternatives, the indication of the preferred second configuration can be transmitted by the WTRU in any of L1 (e.g., UL control information via either PUCCH and PUSCH), UL MAC-CE, UL RRC message.

[0238] The third configuration can be received in either a DCI and an RRC message (e.g., RRCReconfiguration) to be applied to monitoring subsequent PDCCH occasions (e.g., in subsequent time slots, sub-frames, frames, or DRX cycles). In a tenth implementation, the received third configuration can be the same as the indicated second configuration. In an alternative, the received third configuration includes a portion of the indicated second configuration (e.g., values of one or more parameters).

[0239] In some examples, the WTRU can use a first configuration of a search space and / or CORESET received, for example, in either an RRC and a system information message to monitor the PDCCH and receive DCI. The WTRU can perform channel measurements including any of received signal strength, coherence bandwidth, coherence time, delay spread, and Doppler spread. The WTRU can send a measurement report including any of channel state information and power state. The WTRU can receive a second configuration of a search space and / or CORESET to monitor the PDCCH and receive DCI.

[0240] The WTRU performs measurements based on a measurement configuration received in either an RRC (e.g., measConfig in RRCReconfiguration or RRCResume, and MeasIdleConfig in RRCRelease) and system information (e.g., MeasIdleConfigSIB in SIB11) message. The measurement configuration can include parameters that configure a measurement of any of received signal strength measurement, coherence bandwidth, coherence time, delay spread, and Doppler spread to be reported as part of the channel state information.

[0241] Based on the received measurement configuration, measurement report transmission can be periodic. In an alternative, measurement report transmission can be triggered by an event that can be configured as part of the received measurement configuration. The triggering event can be determined by the WTRU as either a first condition regarding the measurement and a second condition regarding the power state, as in previous embodiments. Measurement report transmission can be triggered by a request received from the network in either L1 (e.g., DCI) or MAC-CE signaling. For all alternatives, the measurement report can be sent by the WTRU in either L1 (e.g., UL control information via either PUCCH and PUSCH), UL MAC-CE, or UL RRC message.

[0242] A second configuration (e.g., determined based on the transmitted measurement report) can be received in either an L1 signal (e.g., DCI) and an RRC message (e.g., RRCReconfiguration) to be applied to monitoring subsequent PDCCH occasions (e.g., in subsequent time slots, subframes, frames, or DRX cycles).

[0243] The search space and CORESET configuration can include any of the parameters presented herein for WTRU capabilities, CORESET configuration, search space configuration, and related design considerations, and the DL control channel configuration can be determined according to any of the embodiments presented herein for determining the DL control channel configuration.

[0244] The WTRU may be configured to perform an operational method, wherein the WTRU receives first configuration information that indicates a control channel element (CCE) size, a spreading factor, and an indication of code domain multiplexing (CDM). The WTRU determines second configuration information based on the received first configuration information. The second configuration information may include a resource group (RG) size and a correspondence between the RG size of a CDM RG set and one or more orthogonal cover codes (OCCs). The WTRU may determine a CDM RG set allocation pattern across one or more orthogonal frequency division multiplexing (OFDM) symbols (such as discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols) and one or more frequency resource groups (FRGs) based on the second configuration information. The WTRU may receive a PDCCH transmission and perform an inverse discrete Fourier transform (IDFT) on a plurality of FRGs and the OFDM / DFT-s-OFDM symbols associated with the PDCCH transmission based on the CDM RG set allocation pattern. The WTRU despreads the RG set corresponding to the received PDCCH transmission based on the correspondence of RG to OCC per CDM RG set. The WTRU may decode downlink control information (DCI) in the received PDCCH transmission based on the despread RG set. The first configuration information is contemplated to be static, or at least semi-static. The second configuration information may include a dynamic adaptation of the configuration for decoding the DCI in the PDCCH transmission.

[0245] The WTRU may be configured to: demodulate the OFDM / DFT-s-OFDM symbols received via one or more RGs associated with the PDCCH transmission to determine DL resource scheduling information. The WTRU may also receive a physical downlink shared channel (PDSCH) transmission based on the DL resource scheduling information. The first configuration information may include a search space configuration or a control resource set (CORESET) format. The first configuration information may include the number and size of one or more frequency resource groups (FRGs). The second configuration information may include the number of RGs per control channel element (CCE) and a plurality of CDM RG sets. The WTRU may further determine the second configuration information based on the correspondence of RG to OCC per set, a pre-configured OCC list, and a pre-configured mapping of the RG size to OCC. As indicated, one or more of the FRGs may be associated with a single DFT module.

[0246] The WTRU may be configured to determine, based on an aggregation level and a preconfigured hash function, a CCE index for each PDCCH candidate for the PDCCH transmission. The WTRU may perform an IDFT on the plurality of FRGs and the OFDM / DFT-s-OFDM symbols associated with the PDCCH transmission based on the determined CCE index, the number of RGs per CCE, and the CDMRG set allocation pattern. The WTRU may be configured to demodulate the OFDM / DFT-s-OFDM symbols received over all the RGs associated with the PDCCH transmission; detect a DCI format associated with the PDCCH transmission; and decode the DCI based on the detected DCI format.

[0247] DL control channel configurations may include code domain multiplexed RGs / CCEs. As Figure 6 shown, the WTRU may determine a configuration for proper decoding of PDCCH candidates taking into account code domain multiplexing. At 602, the WTRU may report capabilities for PDCCH decoding, including the number and size of supported DFT modules. At 604, the WTRU may receive PDCCH configurations as search space and CORESET configurations. The search space and CORESET configurations may include any combination of CCE size, spreading factor (or orthogonal code length), number and associated size of FRGs (e.g., DFTs), an indication of code domain multiplexing, and / or CORESET format. At 606, the WTRU may determine RG size and the number of RGs per CCE based on the configured spreading factor, CCE size, and / or FRG size. At 608, the WTRU may determine the CDM RG set size and the association between the RGs and the orthogonal coverage codes (OCCs) per FRG and OFDM symbol based on the configured spreading factor, a preconfigured OCC list, and a preconfigured or known mapping of RG size to OOC. At 610, the WTRU may determine an RG allocation pattern (e.g., across OFDM symbols and FRGs) and a CCE index corresponding to each PDCCH candidate based on the aggregation level, spreading factor, CORESET format, and / or a preconfigured hash function.

[0248] The WTRU may also include a maximum supported number of PDCCH candidates and a maximum number of non-overlapping CCEs supported per serving cell per time slot. The WTRU may determine the RG size of a CCE as a ratio between a configured FRG size and a configured spreading factor. The WTRU may determine the number of RGs per CCE as a ratio between a configured CCE size and the determined RG size. The WTRU may also determine an aggregation level based on a maximum aggregation level indicated in a configured search space and a pre-configured hash function (such as the hash function defined in Equation (D)). The CORESET configuration may also include a CORESET format that indicates any one of the number of OFDM symbols for DCI, the number of OFDM symbols for DMRS, the total number of OFDM symbols for DCI and DMRS, the OFDM symbol index for DCI, and the OFDM symbol index for DMRS. The CORESET format may include a frequency domain configuration that indicates an RE / RB mapping pattern for DMRS and DMRS sequence parameters. The CORESET format may also include an indication of any one of time domain interleaving, frequency domain interleaving, time domain interleaving size, and frequency domain interleaving size. In an embodiment, the CORESET format may include a pre-coding granularity as either FRG-level granularity or CORESET-level granularity. The WTRU may also determine an RG interleaving pattern (i.e., across OFDM symbols and FRGs) based on any one of the number of RGs of code domain multiplexing per FRG, the number of OFDM symbols for DCI, the number of FRGs, time domain interleaving size, and frequency domain interleaving size.

[0249] In an embodiment, such as Figure 7As illustrated, the WTRU determines a configuration for proper decoding of PDCCH candidates considering code domain multiplexing. At 702, the WTRU may receive search space and CORESET configurations. The search space and CORESET configurations may include CCE size, spreading factor, number / size of FRGs, indication of CDM, and / or CORESET format. At 704, the WTRU may determine the RG size, the corresponding number of RGs per CCE, the CDM RG set, and / or the correspondence of RGs to OCCs per set based on the received configuration, a preconfigured OCC list, and a preconfigured or known mapping of RG size to OOC. At 706, the WTRU may determine the CDM RG set allocation pattern across OFDM symbols and FRGs based on the CORESET format and the determined configuration. The WTRU may determine the CCE index for each PDCCH candidate based on the aggregation level and a preconfigured hash function. At 708, the WTRU may receive the PDCCH and decode the DCI via the PDCCH candidates based on the received and determined configurations. At 710, the WTRU may determine the DCI content. The WTRU may perform the corresponding action.

[0250] Receiving the PDCCH may further include: performing IDFT on the FRGs and OFDM symbols associated with the PDCCH candidate based on the determined CCE index, the number of RGs per CCE, and the CDM RG set allocation pattern; extracting / demodulating the RGs corresponding to the PDCCH candidate based on the determined correspondence of RGs to OCCs per CDM RG set, and demodulating the symbols received via all RGs associated with the PDCCH candidate, detecting the DCI format, and decoding the DCI. The DCI content may be downlink resource scheduling information, and the corresponding action may be to receive the PDSCH based on the assigned downlink resources determined according to the scheduling information. The DCI content may be an uplink grant or resource scheduling information, and the corresponding action may be to transmit the PUSCH on the assigned uplink resources determined according to the grant or scheduling information. Additionally, the DCI content may be an indication of the slot format, and the corresponding action may be to determine the slot format.

[0251] As Figure 8As illustrated, the WTRU may determine a configuration for proper decoding of PDCCH candidates considering code domain multiplexing. At 802, the WTRU may receive a search space and CORESET configuration, including CCE size, spreading factor, number / size of FRGs, indication of CDM, and / or CORESET format. At 804, the WTRU may determine the RG size, corresponding number of RGs per CCE, CDM RG set, and corresponding relationship of RGs to OCCs per set based on the received configuration, pre-configured OCC list, and / or pre-configured or known mapping of RG size to OOC. At 806, the WTRU may determine a CDM RG set allocation pattern across OFDM symbols and FRGs based on the CORESET format and the determined configuration. The WTRU may determine a CCE index for each PDCCH candidate based on the aggregation level and a pre-configured hash function. At 808, the WTRU may perform IDFT on the FRGs and OFDM symbols associated with the PDCCH candidate based on the determined CCE index, number of RGs per CCE, and / or CDM RG set allocation pattern. At 810, the WTRU may extract and despread the RGs corresponding to the PDCCH candidate based on the determined corresponding relationship of RGs to OCCs per CDM RG set. At 812, the WTRU may demodulate the symbols received through all RGs associated with the PDCCH candidate, detect the DCI format, and / or decode the DCI. At 814, the WTRU may determine DL resource scheduling information and receive the PDSCH.

[0252] As Figure 9As illustrated, by reporting the WTRU capabilities for PDCCH decoding, the WTRU can determine a configuration for proper decoding of PDCCH candidates considering code domain multiplexing. PDCCH decoding can include the number and size of supported DFT modules. At 902, the WTRU can report the WTRU capabilities for PDCCH decoding. At 904, the WTRU can receive PDCCH configuration as search space and CORESET configuration. The search space and CORESET configuration can include CCE size, number of RGs per CCE, number and associated size of FRGs (e.g., DFTs), indication of code domain multiplexing, and / or CORESET format. At 906, the WTRU can determine the RG size and spreading factor based on the configured CCE size, number of RGs per CCE, and / or FRG size. At 908, the WTRU can determine the number of multiplexed RGs and the association between the RGs and orthogonal cover codes (OCCs) per FRG and OFDM symbol based on the determined spreading factor, pre-configured OCC list, and / or pre-configured or known mapping of RG size to OOC. At 910, the WTRU can determine the RG allocation pattern (e.g., across OFDM symbols and FRGs) and the CCE index corresponding to each PDCCH candidate based on the aggregation level, spreading factor, CORESET format, and / or pre-configured hash function.

[0253] The WTRU can determine the RG size of a CCE as the ratio between the configured CCE size and the configured number of RGs per CCE. Additionally, the WTRU can determine the spreading factor defining code domain multiplexing per FRG and OFDM symbol as the ratio between the configured FRG size and the determined RG size.

[0254] As Figure 10As illustrated, the WTRU may determine a configuration for proper decoding of PDCCH candidates considering code domain multiplexing. At 1002, the WTRU may report WTRU capabilities for PDCCH decoding, which may include the number and size of supported DFT modules. At 1004, the WTRU may receive PDCCH configurations as search space and CORESET configurations. The search space and CORESET configurations may include a spreading factor, the number of RGs per CCE, the number and associated size of FRGs (e.g., DFTs), an indication of code domain multiplexing, and / or CORESET format. At 1006, the WTRU may determine the RG size and CCE size based on one or more of the configured spreading factor, the number of RGs per CCE, and / or FRG size. At 1008, the WTRU may determine the number of multiplexed RGs and the association between the RGs and orthogonal cover codes (OCCs) per FRG and OFDM symbol based on the configured spreading factor, a preconfigured OCC list, and / or a preconfigured or known mapping of RG size to OOC. At 1010, the WTRU may determine the RG allocation pattern (e.g., across OFDM symbols and FRGs) and the CCE index corresponding to each PDCCH candidate based on the aggregation level, spreading factor, CORESET format, and / or a preconfigured hash function.

[0255] The WTRU may determine the RG size of a CCE as the ratio between the configured FRG size and the configured spreading factor. Additionally, the WTRU may determine the CCE size as the product of the configured number of RGs per CCE and the determined RG size.

[0256] As Figure 11As illustrated, the WTRU may determine a configuration for proper decoding of PDCCH candidates considering code domain multiplexing. At 1102, the WTRU may report WTRU capabilities for PDCCH decoding, including the number and size of supported DFT modules. At 1104, the WTRU may receive PDCCH configurations as search space and CORESET configurations. The search space and CORESET configurations may include CCE size, spreading factor (e.g., or orthogonal code length), number of RGs per CCE, number and associated size of FRGs (e.g., DFTs), indication of code domain multiplexing, and / or CORESET format. At 1106, the WTRU may determine RG size and CDM RG set size based on the configured spreading factor, CCE size, and / or number of RGs per CCE. At 1108, the WTRU may determine the number of CDM RG sets for multiplexing per FRG and OFDM symbol based on the determined RG size, configured spreading factor, and / or FRG size. At 1110, the WTRU may determine the number of TREs (e.g., TRE block size) per CDM RG set within each FRG based on RG size, spreading factor, FRG size, system bandwidth, and / or subcarrier spacing. At 1112, the WTRU may determine the number of TRE blocks within each FRG based on the number of CDM RG sets per FRG and OFDM symbol and the CORESET format. At 1114, the WTRU may determine the RG allocation pattern (e.g., across OFDM symbols and FRGs) and CCE indices corresponding to each PDCCH candidate based on aggregation level, spreading factor, CORESET format, and / or preconfigured hash function.

[0257] The WTRU may determine the number of CDM RG sets multiplexed in the time domain per FRG and OFDM symbol as the ratio between the FRG size and the product of the spreading factor and RG size. The WTRU may determine the number of TREs associated with each CDM RG set in the FRG as the product of the RG size, spreading factor, and the ratio of the IFFT module size to the DFT module size, where the DFT module size corresponds to the FRG size and the IFFT module size corresponds to the number of subcarriers in an OFDM system with a specific system bandwidth and specific subcarrier spacing. The WTRU may also determine the number of TRE blocks within each FRG as the product of the determined number of CDM RG sets per FRG and OFDM symbol and the number of OFDM symbols allocated for DCI determined according to the CORESET format. Additionally, the WTRU may determine the RG interleaving pattern (i.e., across TRE blocks and FRGs) based on any one of the number of RGs for code domain multiplexing per FRG, number of OFDM symbols for DCI, number of FRGs, time domain interleaving size, and frequency domain interleaving size.

[0258] The DL control channel configuration may include WTRU-assisted CORESET configuration adaptation. Referring to the discussion above, in an embodiment such as Figure 12 shown, the WTRU may dynamically determine the configuration for proper decoding of PDCCH candidates (including, for example, DCI in the PDCCH). The dynamic determination may include considering code domain multiplexing. At 1202, the WTRU may report the WTRU capabilities for PDCCH decoding, for example, including the number and size of supported DFT modules. At 1204, the WTRU may receive the PDCCH configuration as a search space and CORESET configuration. The search space and CORESET configuration may include CCE size, spreading factor (or orthogonal code length), number and associated size of FRGs (e.g., DFTs), indication of code domain multiplexing, and / or CORESET format. At 1206, the WTRU may determine the RG size and the number of RGs per CCE based on one or more of the configured spreading factor, CCE size, and / or FRG size. At 1208, the WTRU may determine the CDM RG set size and the association between the RG and the orthogonal cover code (OCC) per FRG and OFDM symbol based on the configured spreading factor, pre-configured OCC list, and pre-configured or known mapping of RG size to OOC; and (c) determine the RG allocation pattern (i.e., across OFDM symbols and FRGs) and the CCE index corresponding to each PDCCH candidate based on the aggregation level, spreading factor, CORESET format, and pre-configured hash function. At 1210, if the set conditions are not met, the WTRU may perform channel measurements again, such as at 1206. If the conditions are met or the measurement period has ended, at 1214, the WTRU may send a measurement report that includes either channel state information or power state. At 1216, the WTRU may receive a second configuration of the search space and / or CORESET to monitor the PDCCH and received DCI based on one or more sent measurement reports. Once the second configuration is received, the WTRU may perform channel measurements again, such as at 1206.

[0259] The WTRU capabilities may also include the maximum number of PDCCH candidates supported and the maximum number of non-overlapping CCEs supported per serving cell per time slot. The WTRU may determine the RG size of a CCE as the ratio between the configured FRG size and the configured spreading factor. The WTRU may also determine the number of RGs per CCE as the ratio between the configured CCE size and the determined RG size. Additionally, the WTRU may determine the aggregation level based on the maximum aggregation level indicated in the configured search space, and the pre-configured hash function may be defined according to equation (D) herein. The CORESET configuration may include a CORESET format that indicates any one of the number of OFDM symbols for DCI, the number of OFDM symbols for DMRS, the total number of OFDM symbols for DCI and DMRS, the OFDM symbol index for DCI, and the OFDM symbol index for DMRS. The CORESET format may also include a frequency domain configuration that indicates the RE / RB mapping pattern for DMRS and the DMRS sequence parameters. Additionally, the CORESET format may include an indication of any one of time domain interleaving, frequency domain interleaving, time domain interleaving size, and frequency domain interleaving size. The CORESET format may also include a pre-coding granularity as either FRG-level granularity or CORESET-level granularity. The WTRU may determine the RG interleaving pattern (i.e., across OFDM symbols and FRGs) based on any one of the number of RGs of code domain multiplexing per FRG, the number of OFDM symbols for DCI, the number of FRGs, time domain interleaving size, and frequency domain interleaving size.

Claims

1. A wireless transmit / receive unit (WTRU), the wireless transmit / receive unit (WTRU) comprises: a processor configured to: receive first configuration information indicating a control channel element (CCE) size, a spreading factor, and an indication of code domain multiplexing (CDM); determine second configuration information based on at least one of the factors in the received first configuration information, wherein the second configuration information includes a resource group (RG) size and a correspondence between the RG size of a CDM RG set and one or more orthogonal cover codes (OCCs); determine a CDM RG set allocation pattern across one or more discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) symbols and frequency resource groups (FRGs) based on the determined second configuration information; receive a PDCCH transmission; perform an inverse discrete Fourier transform (IDFT) on a plurality of FRGs and DFT-s-OFDM symbols associated with the PDCCH transmission based on the CDM RG set allocation pattern; despread an RG set corresponding to the PDCCH transmission based on the correspondence between the RG and one or more OCCs per CDM RG set; and decode downlink control information (DCI) in the PDCCH transmission based on the despread RG set.

2. The WTRU according to claim 1, wherein the first configuration information is static or semi-static, and wherein the second configuration information includes a dynamic adaptation of a configuration for decoding the DCI in the PDCCH transmission.

3. The WTRU according to claim 1, wherein the processor is further configured to: demodulate the DFT-s-OFDM symbols received through one or more RGs associated with the PDCCH transmission to determine DL resource scheduling information; and receive a physical downlink shared channel (PDSCH) transmission based on the DL resource scheduling information.

4. The WTRU according to claim 1, wherein the first configuration information includes a search space configuration or a control resource set (CORESET) format.

5. The WTRU according to claim 1, wherein the first configuration information includes the number and size of one or more frequency resource groups (FRGs).

6. The WTRU according to claim 5, wherein the one or more FRGs are associated with a single DFT module.

7. The WTRU according to claim 1, wherein the second configuration information further includes the number of RGs per control channel element (CCE) and a plurality of CDM RG sets.

8. The WTRU according to claim 1, wherein the processor is configured to further determine the second configuration information based on the correspondence between the RG and the OCC per CDM RG set, a pre-configured OCC list, and a pre-configured mapping of the RG size to the OOC.

9. The WTRU according to claim 1, wherein the processor is configured to: Determine a CCE index for each PDCCH candidate for the PDCCH transmission based on an aggregation level and a pre-configured hash function; and Perform the IDFT on the plurality of FRGs and the DFT-s-OFDM symbols associated with the PDCCH transmission based on the determined CCE index, the number of RGs per CCE, and the CDM RG set allocation pattern.

10. The WTRU according to claim 1, wherein the processor is configured to: Demodulate the DFT-s-OFDM symbols received over all RGs associated with the PDCCH transmission; Detect a DCI format associated with the PDCCH transmission; and Decode the DCI based on the detected DCI format.

11. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: Receiving first configuration information indicating a control channel element (CCE) size, a spreading factor, and an indication of code domain multiplexing (CDM); Determining second configuration information based on at least one of the received first configuration information, wherein the second configuration information includes an RG size and a correspondence between the RG size of a CDM RG set and one or more orthogonal cover codes (OCCs); Determining a CDM RG set allocation pattern across one or more discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) symbols and frequency resource groups (FRGs) based on the determined second configuration information; Receiving a PDCCH transmission; Performing an inverse discrete Fourier transform (IDFT) on the plurality of FRGs and DFT-s-OFDM symbols associated with the PDCCH transmission based on the CDM RG set allocation pattern; Despreading a set of RGs corresponding to the PDCCH transmission based on the correspondence between the RG per CDM RG set and one or more OCCs; and Decoding downlink control information (DCI) in the PDCCH transmission based on the despread set of RGs.

12. The method according to claim 11, wherein the first configuration information is static or semi-static, and wherein the second configuration information includes a dynamic adaptation of a configuration for decoding the DCI in the PDCCH transmission.

13. The method according to claim 11, the method further comprising: Demodulating the DFT-s-OFDM symbols received over one or more RGs associated with the PDCCH transmission to determine DL resource scheduling information; and Receiving a physical downlink shared channel (PDSCH) transmission based on the DL resource scheduling information.

14. The method according to claim 11, wherein the first configuration information includes a search space configuration or a control resource set (CORESET) format.

15. The method according to claim 11, wherein the second configuration information further includes the number of RGs per control channel element (CCE) and a plurality of CDM RG sets.

16. The method according to claim 11, the method further comprises: determining the second configuration information based on the correspondence between the RG and the OCC of each CDM RG set, a pre-configured OCC list, and a pre-configured mapping from the RG size to the OOC.

17. The method according to claim 11, the method further comprises: determining a CCE index for each PDCCH candidate for the PDCCH transmission based on an aggregation level and a pre-configured hash function; and performing an IDFT on the plurality of FRGs and the DFT-s-OFDM symbols associated with the PDCCH transmission based on the determined CCE index, the number of RGs per CCE, and the CDM RG set allocation pattern.

18. The method according to claim 11, the method further comprises: demodulating the DFT-s-OFDM symbols received through all the RGs associated with the PDCCH transmission; detecting a DCI format associated with the PDCCH transmission; and decoding the DCI based on the detected DCI format.

19. A method performed by a wireless transmit / receive unit (WTRU), the method comprises: receiving first configuration information indicating a control channel element (CCE) size, a spreading factor, and an indication of code domain multiplexing (CDM); determining second configuration information based on at least one of the factors in the received first configuration information, wherein the second configuration information includes an RG size and a correspondence between the RG size of a CDM RG set and one or more orthogonal cover codes (OCC); determining a CDM RG set allocation pattern across one or more orthogonal frequency division multiplexing (OFDM) symbols and frequency resource groups (FRG) based on the determined second configuration information; receiving a PDCCH transmission; performing an inverse discrete Fourier transform (IDFT) on the plurality of FRGs and the OFDM symbols associated with the PDCCH transmission based on the CDM RG set allocation pattern; despreading an RG set corresponding to the PDCCH transmission based on the correspondence between the RG of each CDM RG set and one or more OCC; and decoding downlink control information (DCI) in the PDCCH transmission based on the despread RG set.

20. The method according to claim 19, wherein the first configuration information is static or semi-static, and wherein the second configuration information includes a dynamic adaptation of a configuration for decoding the DCI in the PDCCH transmission.

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